Skocz do pozycji: 1.

Tytuł:

Automatic Measurement System of Hydrated Sodium Silicate Composition Analysis

Autorzy:

Wang, Huafang
Wang, Quanrun
Zhang, Wu
Gao, Xiang
Lu, Jijun

Powiązania:

https://bibliotekanauki.pl/articles/1837674.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

hydrated sodium silicate
composition analysis
potentiometr
titration
uwodniony krzemian sodu
analiza składu
potencjometr
miareczkowanie

Opis:

Sodium silicate is one of the most successful inorganic binder. Along with the broad application of sodium silicate for domestic and industrial purposes, the composition analysis, include modulus (m), ratio of SiO2:Na2O, Na2O%, SiO2%, and solid-containing content, is important for the products strength and service life. However, it is perplexing to operate, inefficient and low precision for traditional standard testing method of these parameters. In this study, an automatic measurement system of sodium silicate composition analysis, with the potential electrode for potentiometer titration, micro-controller, PCB, heater, stirrer, printer and micro peristaltic pump, was developed according to the determine method principle. The end-points of pH value in the two titrating steps, first was 4.3 and second was 6.0, were set in the micro-controller to control the reaction in the processing of the sodium silicate composition analysis. And all the potential signals of the pH electrode were transited in the special PCB for the micro-controller.

Źródło:

Archives of Foundry Engineering; 2021, 21, 2; 5-8
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

Tytuł:

Theoretical Studies of the Spin Hamiltonian Parameters and Local Structures for the Two Tetragonal $Cu^{2+}$ Centers in $Ca(OH)_2$

Autorzy:

Zhang, H.
Wu, S.
Zhang, Z.

Powiązania:

https://bibliotekanauki.pl/articles/1493658.pdf

Data publikacji:

2011-09

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

76.30.Fc

Opis:

The spin Hamiltonian parameters (g factors $g_{∥ },$ $g_{⊥}$ and the hyperfine structure constants $A_{∥ },$ $A_{⊥}$) and the local structures for the two tetragonal $Cu^{2+}$ centers I and II in $Ca(OH)_2$ are theoretically studied from the perturbation formulae of these parameters for a $3d^9$ ion under tetragonally elongated octahedra. The $[Cu(OH)_6]^{4-}$ clusters on the substitutional $Ca^{2+}$ site are found to suffer the relative elongations by about 0.083 Å and 0.065 Å for centers I and II, respectively, along the $C_4$ axis due to the Jahn-Teller effect. The above tetragonal elongations may entirely depress the original trigonal distortion of the host $Ca^{2+}$ site in $Ca(OH)_2$. The calculated spin Hamiltonian parameters based on the above Jahn-Teller elongations show good agreement with the experimental results. The EPR spectra and the local structures for the two centers are compared with one another.

Źródło:

Acta Physica Polonica A; 2011, 120, 3; 507-511
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Per-Spectral Characterizations Of Some Bipartite Graphs

Autorzy:

Wu, Tingzeng
Zhang, Heping

Powiązania:

https://bibliotekanauki.pl/articles/31341599.pdf

Data publikacji:

2017-11-27

Wydawca:

Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii

Tematy:

permanent
permanental polynomial
per-spectrum
cospectral

Opis:

A graph is said to be characterized by its permanental spectrum if there is no other non-isomorphic graph with the same permanental spectrum. In this paper, we investigate when a complete bipartite graph K_p,p with some edges deleted is determined by its permanental spectrum. We first prove that a graph obtained from K_p,p by deleting all edges of a star K_1,l, provided l < p, is determined by its permanental spectrum. Furthermore, we show that all graphs with a perfect matching obtained from K_p,p by removing five or fewer edges are determined by their permanental spectra.

Źródło:

Discussiones Mathematicae Graph Theory; 2017, 37, 4; 935-951
2083-5892

Pojawia się w:

Discussiones Mathematicae Graph Theory

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

Experimental and optimization design of offshore drilling seal

Autorzy:

Zhang, Y.
Zhang, X.
Chang, X.
Wu, Q.

Powiązania:

https://bibliotekanauki.pl/articles/260627.pdf

Data publikacji:

2017

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

offshore drilling
design optimization
seals
finite element analysis
MATLAB

Opis:

Three-cone bit is the key equipment in the exploration of the oil in offshore drilling and exploration, the bearing system and the seal system are the critical components for the bit. Especially in the offshore drilling environment, the seal design need to be carefully considered. A multi-objective optimization design including orthogonal design method and F-test with finite element analysis for a three-cone bit seal is proposed. Firstly, the calculation method of optimization targets are given, including the minimization of maximum contact pressure and leakage rate analyzed by ANSYS and MATLAB respectively, to maximize seal life and reliability. Then, an orthogonal experiment approach is used to investigate the effects of the eleven parameters on the seal performance, and the influence degrees of the seal factors on the optimization targets have been confirmed by F-test, and the reasonable factors can be determined by the trend of the targets. Finally, in order to validate the analysis results, a new seal was designed and tested on a seal tester compared to the previous seal. In this test, the seal maximum interface temperature that reflects the position of maximum contact pressure can be obtained by using three high precision thermocouples. Both the experiment results and the numerical analyses proved that the maximum contact pressure and leakage rate of the improved seal have been reduced compared to the previous.

Źródło:

Polish Maritime Research; 2017, S 3; 72-78
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

The Critical Conditions and Kinetics Required for Dynamic Recrystallization in a High-Carbon Tool Steel

Autorzy:

Zhang, Yong-Ji
Wu, Guang-Lian
Wu, Shang-Wen

Powiązania:

https://bibliotekanauki.pl/articles/2049419.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

high-carbon steel
critical conditions
dynamic recrystallization
work-hardening
kinetics model

Opis:

A hot compression test was conducted on a Gleeble-3500 thermo-simulation machine to study the critical conditions and kinetics of dynamic recrystallization in a high-carbon tool steel. The critical conditions for the initiation of dynamic recrystallization were determined using the working-hardening theory. The quantitative relationship between the critical characteristics of dynamic recrystallization and the hot deformation parameters were elucidated based on two different methods: the apparent method and physically based method. It was found that the two methods both have high applicability for the investigated steel, but the physically-based method needs less parameters and makes it possible to study the effect of different factors. A dynamic recrystallization kinetics model was used to calculate the recrystallization volume fraction under different conditions. The calculation results matched well with the data obtained from the flow curves.

Źródło:

Archives of Metallurgy and Materials; 2021, 66, 1; 119-125
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

Building a non-homogeneous thermal environment for energy savings in the face of deep mines

Autorzy:

Li, Xian
Wu, Yaru
Zhang, Yunfei

Powiązania:

https://bibliotekanauki.pl/articles/2073873.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

kopalnia
chłodzenie kopalni
klimatyzacja w kopalni
mine face
cooling strategy
non-homogeneous environment
air cooler
necessary cooling space

Opis:

Heat exhaustion of mining environments can cause a significant threat to human health. The existing cooling strategies for the mine face aim to cool the whole face. However, the necessary cooling space for the face is small, with a considerable amount of energy for cooling being wasted. Necessary cooling space is a space occupied by the workers in the face. This study proposed to build a non-homogeneous thermal environment for cost-effective energy savings in the face. An inlet air cooler was laid out in the intake airway to cool the whole face to some extent, and the tracking air cooler was designed to track the worker who constantly moved to improve the thermal environment. The cooling load and air distribution for this cooling strategy were investigated. In addition, the airflow in the face was solved numerically to estimate the cooling effect. The results revealed that an average energy saving of approximately 35% could be achieved. The thermal environment of the necessary cooling space within at least 10 m was significantly improved. This cooling strategy should be taken into account in mine cooling.

Źródło:

Archives of Mining Sciences; 2021, 66, 3; 457--474
0860-7001

Pojawia się w:

Archives of Mining Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

A novel deep penetrating eddy current probe based on phase shifted fields and its application to inspection of defects

Autorzy:

Wu, Meixian
Zhang, Dongli
Wang, Chuanglong

Powiązania:

https://bibliotekanauki.pl/articles/221582.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

skin effect
penetration depth
austenitic stainless steel
eddy current probe
phase shifted fields

Opis:

Due to the skin effect of eddy currents, the depth of cracks which can be detected by the traditional eddy current probe is very limited. In order to improve the ability of eddy current probes to inspect deep cracks in metal thick-walled structures, a new eddy current probe using an excitation system with phase shifted fields was proposed. Its feasibility for detecting deep cracks was verified by simulation and experiments. The results showed that the penetration depth of eddy currents in austenitic stainless steel is effectively enhanced by using the new probe.

Źródło:

Metrology and Measurement Systems; 2020, 27, 2; 275-287
0860-8229

Pojawia się w:

Metrology and Measurement Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Non-fragile event-triggered control of positive switched systems with random nonlinearities and controller perturbations

Autorzy:

Wu, Yanqi
Zhang, Junfeng
Fu, Shizhou

Powiązania:

https://bibliotekanauki.pl/articles/2086895.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

positive switched systems
non-fragile event-triggered control
random nonlinearities
random controller perturbations
systemy przełączane dodatnio
kontrola niedelikatna wyzwalana zdarzeniami
nieliniowość losowa
perturbacja kontrolera losowa

Opis:

This paper investigates the non-fragile event-triggered control of positive switched systems with random nonlinearities and controller perturbations. The random nonlinearities and controller perturbations are assumed to obey Bernoulli and Binomial sequence, respectively. A class of linear event-triggering conditions is introduced. A switched linear co-positive Lyapunov function is constructed for the systems. For the same probability with respect to nonlinearities and controller perturbations in each subsystem, a non-fragile controller of positive switched systems is designed in terms of linear programming. Then, the different probability case is considered and the corresponding non-fragile event-triggered control is explored. Finally, the effectiveness of theoretical findings is verified via two examples.

Źródło:

Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 5; e138566, 1--12
0239-7528

Pojawia się w:

Bulletin of the Polish Academy of Sciences. Technical Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

Extremal Matching Energy of Complements of Trees

Autorzy:

Wu, Tingzeng
Yan, Weigen
Zhang, Heping

Powiązania:

https://bibliotekanauki.pl/articles/31340889.pdf

Data publikacji:

2016-08-01

Wydawca:

Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii

Tematy:

matching polynomial
matching energy
Hosoya index
energy

Opis:

Gutman and Wagner proposed the concept of the matching energy which is defined as the sum of the absolute values of the zeros of the matching polynomial of a graph. And they pointed out that the chemical applications of matching energy go back to the 1970s. Let $T$ be a tree with n vertices. In this paper, we characterize the trees whose complements have the maximal, second-maximal and minimal matching energy. Furthermore, we determine the trees with edge-independence number p whose complements have the minimum matching energy for $ p = 1, 2, . . ., \floor{ n/2 } $. When we restrict our consideration to all trees with a perfect matching, we determine the trees whose complements have the second-maximal matching energy.

Źródło:

Discussiones Mathematicae Graph Theory; 2016, 36, 3; 505-521
2083-5892

Pojawia się w:

Discussiones Mathematicae Graph Theory

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

The Existence Of P_≥3-Factor Covered Graphs

Autorzy:

Zhou, Sizhong
Wu, Jiancheng
Zhang, Tao

Powiązania:

https://bibliotekanauki.pl/articles/31341575.pdf

Data publikacji:

2017-11-27

Wydawca:

Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii

Tematy:

P≥3-factor
P≥3-factor covered graph
toughness
isolated toughness
regular graph

Opis:

A spanning subgraph F of a graph G is called a P_≥3-factor of G if every component of F is a path of order at least 3. A graph G is called a P_≥3-factor covered graph if G has a P_≥3-factor including e for any e ∈ E(G). In this paper, we obtain three sufficient conditions for graphs to be P_≥3-factor covered graphs. Furthermore, it is shown that the results are sharp.

Źródło:

Discussiones Mathematicae Graph Theory; 2017, 37, 4; 1055-1065
2083-5892

Pojawia się w:

Discussiones Mathematicae Graph Theory

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Theoretical Study of Energy Levels and Transition Probabilities of Boron Atom

Autorzy:

Tian-yi, Zhang
Neng-wu, Zheng

Powiązania:

https://bibliotekanauki.pl/articles/1807769.pdf

Data publikacji:

2009-08

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

01.55.+b
31.15.-p

Opis:

Though the electrons configuration for boron atom is simple and boron atom has long been of interest for many researchers, the theoretical studies for properties of BI are not systematic, there are only few results reported on energy levels of high excited states of boron, and transition measurements are generally restricted to transitions involving ground states and low excited states without considering fine structure effects, provided only multiplet results, values for transitions between high excited states are seldom performed. In this article, by using the scheme of the weakest bound electron potential model theory calculations for energy levels of five series are performed and with the same method we give the transition probabilities between excited states with considering fine structure effects. The comprehensive set of calculations attempted in this paper could be of some value to workers in the field because of the lack of published calculations for the BI systems. The perturbations coming from foreign perturbers are taken into account in studying the energy levels. Good agreement between our results and the accepted values taken from NIST has been obtained. We also reported some values of energy levels and transition probabilities not existing on the NIST data bases.

Źródło:

Acta Physica Polonica A; 2009, 116, 2; 141-153
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Performance optimization of organic Rankine cycles for waste heat recovery for a large diesel engine

Autorzy:

Ma, Z.
Wu, J.
Zhang, Y.

Powiązania:

https://bibliotekanauki.pl/articles/240064.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

low grade waste heat
organic rankine cycle
thermodynamic optimization
thermoeconomic optimization
intelligent marine diesel engine
organiczny obieg Rankine'a
optymalizacja termodynamiczna
optymalizacja termoekonomiczna

Opis:

In order to recover the low grade waste heat and increase system fuel economy for main engine 10S90ME-C9.2-TII(part load, exhaust gas bypass) installed on a 10000 TEU container ship, a non-cogeneration and single-pressure type of waste heat recovery system based on organic Rankine cycle is proposed. Organic compound candidates appropriate to the system are analyzed and selected. Thermodynamic model of the whole system and thermoeconomic optimization are performed. The saturated organic compound vapor mass flow rate, net electric power output, pinch point, thermal efficiency and exergy efficiency varied with different evaporating temperature are thermodynamically analyzed. The results of thermodynamic and thermoeconomic optimization indicate that the most appropriate organic compound candidate is R141b due to its highest exergy efficiency, biggest unit cost benefit and shortest payback time.

Źródło:

Archives of Thermodynamics; 2018, 39, 1; 3-23
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Mathematical Model of Embedded Temperature Sensing Fabric Heat Transmission
Matematyczny model przepływu ciepła w tkaninie z umieszczonym w niej czujniku temperatury

Autorzy:

Zhang, R.
Deng, N.
Cheng, B.
Zhang, S.
Wu, Y.

Powiązania:

https://bibliotekanauki.pl/articles/949451.pdf

Data publikacji:

2016

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych

Tematy:

temperature sensing fabric
mathematical model
surface contact thermal resistance
testing system
temperature value
tkanina
czujnik temperatury
model matematyczny
oporność termiczna
system testowania
wartość temperatury

Opis:

In order to explore effect factors in the measurement of temperature sensing fabric, a heat transmission mathematical model of temperature sensing fabric was established. The concept of surface contact thermal resistance associated with the material thermal conductivity, fabric layer number and yarn linear density between the fabric and sensor was proposed in the model, whose surface contact thermal resistance was produced in the process of fabric heat transmission. Some test samples were woven to prove the rationality of the model. The results demonstrated that the value measured would be influenced by the performances of surface contact thermal resistance, which was consistent with the derivation of the theoretical model. The raw material, fabric layer number and yarn linear density of temperature sensing fabric had a great effect on the measurement value. The correlation coefficient reached more than 0.988 among the experimental and theoretical values, respectively, which proved that the heat transmission mathematical model of temperature sensing fabric could be applied in the research of this fabric.
Opracowano matematyczny model przepływu ciepła przez tkaninę zawierającą wbudowane czujniki temperatury w celu określenia wpływu poszczególnych czynników na przebieg pomiarów. Brano pod uwagę oporność termiczną styku czujników z tkaniną związaną z przewodnością termiczną materiału, ilość warstw i masę liniową przędz w obrębie tkaniny i czujników. Uzyskane współczynniki korelacji pomiędzy wartościami eksperymentalnymi i teoretycznymi przekraczały 0,988 co potwierdza, że opracowany przez nas matematyczny model przepływu ciepła w tkaninie pomiarowej można zastosować w tego typu badaniach.

Źródło:

Fibres & Textiles in Eastern Europe; 2016, 5 (119); 73-79
1230-3666
2300-7354

Pojawia się w:

Fibres & Textiles in Eastern Europe

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Research on beam supply control strategy based on sliding mode control

Autorzy:

Zhang, Hao
Dong, Haiying
Zhang, Baoping
Wu, Tong
Chen, Changwen

Powiązania:

https://bibliotekanauki.pl/articles/141014.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

beam supply
DC/DC converter
robustness
sliding mode control

Opis:

In the hybrid multiple H-bridge topology of beam supply, the load change of a DC/DC full-bridge converter can greatly affect the output voltage during onsite operation. An improved sliding mode control (SMC) strategy is thus proposed in this paper, where the rate of switching control is added to the law of system equivalent control to create a law that can realize a complete sliding mode control. Considering the special operating conditions of the load can have an influence on the performance of the controller, the impact of uncertainty existing in onsite conditions is suppressed with the proposed strategy utilized. The validity of the proposed strategy, finally, is verified by simulation, which proves the outperformance of the system in both robustness and dynamics.

Źródło:

Archives of Electrical Engineering; 2020, 69, 2; 349-364
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Emergency management of maritime accidents in the yangtze river: problems, practice and prospects

Autorzy:

Yan, X.P.
Wu, B.
Zhang, D.
Zhang, J. F.

Powiązania:

https://bibliotekanauki.pl/articles/117335.pdf

Data publikacji:

2017

Wydawca:

Uniwersytet Morski w Gdyni. Wydział Nawigacyjny

Tematy:

inland navigation
emergency management
Yangtze River
maritime accidents
artificial societies
Computational Experiments and Parallel Execution (ACP)
eastern star
inland shipping
oil spill

Opis:

Maritime accidents have received considerable attentions due to the enormous property damage, casualties and serious environmental pollution. This paper first makes statistical analysis of the different types of maritime accidents in the period of 2012 to 2014 in the Yangtze River. Second, the problems of emergency management of maritime accidents are also proposed from the analysis of the major accident “Eastern Star”.. Afterwards, four practice cases, including decision support for maritime accidents, emergency resource allocation, emergency simulation system and effectiveness of emergency management, are introduced to present the insights gained from these practices. Last, in order to address these problems, this paper proposes that an artificial societies, Computational experiments, and Parallel execution (ACP) approach should be introduced to establish an improved management system for maritime accidents in the future, and an ACP based maritime accident emergency management framework is proposed.

Źródło:

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2017, 11, 1; 111-118
2083-6473
2083-6481

Pojawia się w:

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Oxygen-containing Tetrazole Salts of 3-Hydrazino-4-amino-1,2,4-triazole (HATr): Nitrogen-rich Ionic Materials with High Thermal Stability

Autorzy:

Wu, J.-T.
Zhang, J.-G.
Yin, X.
Li, T.
Wu, L.
Zhang, Z.-B.

Powiązania:

https://bibliotekanauki.pl/articles/358927.pdf

Data publikacji:

2017

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

energetic salts
thermal stability
oxygen-containing tetrazoles
3-hydrazino-4-amino-1,2,4-triazole

Opis:

Energetic salts of doubly-protonated 3-hydrazino-4-amino-1,2,4-triazole (2-4), and mono-protonated 3-hydrazino-4-amino-1,2,4-triazole (5-7), have been prepared in high yields from the corresponding oxygen-containing tetrazoles by (i) reaction of free acids and neutral 3-hydrazino-4-amino-1,2,4-triazole, or (ii) metathesis reactions of 3-hydrazinium-4-amino-1H-1,2,4-triazolium di-chloride with the silver salts of the corresponding oxygen-containing tetrazoles. All of these energetic salts were fully characterized by single-crystal X-ray diffraction, FT-IR and DSC measurements. All of the structures are dominated by extensive hydrogen bonds due to amino groups, hydrazino groups and oxygen atoms in the molecules. These salts exhibit good thermal stability, especially the salt 3-hydrazinium-4-amino-1H-1,2,4-triazolium 1H,1’H-5,5’-bitetrazole-1,1’-diolate (4), which exhibits a measured onset of decomposition temperature of 237 °C. Quantum chemical calculations, carried out using the Gaussian 03 suite of programs and based on the experimental densities were used to calculate the detonation pressures and velocities of all of the salts.

Źródło:

Central European Journal of Energetic Materials; 2017, 14, 1; 217-232
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Effect of provenance and water stress on biomass and polyphyllin content in the medicinal plant Paris polyphylla Smith var. yunnanensis

Autorzy:

Wu, X.
Zuo, .
Zhang, Q.
Wang, Y.

Powiązania:

https://bibliotekanauki.pl/articles/12304075.pdf

Data publikacji:

2019

Wydawca:

Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie

Tematy:

plant cultivation
Paris polyphylla
medicinal plant
herbal plant
water stress
biomass
polyphyllin content

Opis:

Water stress and provenance could affect the secondary metabolites synthesis and accumulation in herbs. Thus, this study explored the effect of soil water moisture and provenance on the growth of Paris polyphylla Smith var. yunnanensis (PPY). Three provenances (Jinping, Luquan and Weixi in Yunnan, China) of PPY samples were grown in different soil water moisture conditions [0.80, 0.70 and 0.50 field capacity (FC)] during Dec. 2015 to Sep. 2017. Results showed that the highest biomass weight was presented in 0.70 FC for Luquan and Weixi samples. Biomass weight for Jinping provenance presented a decreasing tendency with the decreased soil water moisture and the highest biomass were shown in 0.80 FC. However, quantitative analysis revealed that the total content of polyphyllin increased with decreasing the soil water moisture for Jinping and Weixi samples. The highest total content of polyphyllin in rhizome was inclined to show in Jinping samples, while the stem and leaf tissues were shown in Weixi samples. Additionally, results of ANOVA combined with PCA indicated that the difference among these three provenances were significant. Correlation analysis results revealed that 0.50 FC induced the competitive relationship occurrence for polyphyllin distribution. Thus, 0.70 FC was the most suitable soil-water condition for PPY growth. Besides, provenance collected from Jinping could consider as a good quality germplasm. Consequently, this study might provide a preliminary foundation for irrigation project formulated and provenance screened for PPY cultivation.

Źródło:

Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 2; 171-191
1644-0692

Pojawia się w:

Acta Scientiarum Polonorum. Hortorum Cultus

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Energetic Nitrogen-rich Salts

Autorzy:

Wu, J.-W.
Zhang, J.-G.
Zhang, T.-L.
Yang, L.

Powiązania:

https://bibliotekanauki.pl/articles/358479.pdf

Data publikacji:

2015

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

energetic salts
synthesis
characterization
crystal structure
review

Opis:

Energetic salts as a unique class of energetic materials have recently been investigated widely, since they possess advantages over their atomically similar nonionic analogues – they tend to exhibit lower vapor pressures, higher densities and better thermal stabilities. Furthermore, these salts are readily improved upon by the appropriate combination of different cations and anions. Over the last twenty years, our group has continued to synthesize and study novel ionic energetic materials. Here, we have summarized all of the series of nitrogen-rich energetic salts. This review gives an overview of the various studies dealing with synthetic aspects and some of the physicochemical properties of ionic compounds that are based on ammonia, guanidine, semicarbazide, carbohydrazide, tetrazine, tetrazole, triazole and imidazole. In addition, their potential applications in the fields of explosives and propellants are discussed. We hope these investigations will be helpful in providing a wider insight for future research in the area of energetic salts.

Źródło:

Central European Journal of Energetic Materials; 2015, 12, 3; 417-437
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

Usefulness of nonlinear interpolation and particle filter in Zigbee indoor positioning
Wykorzystanie nieliniowej interpolacji oraz filtru cząsteczkowego w pozycjonowaniu wewnątrz pomieszczeń przy użyciu technologii Zigbee

Autorzy:

Zhang, X.
Guo, H.
Wu, H.
Uradziński, M.

Powiązania:

https://bibliotekanauki.pl/articles/145368.pdf

Data publikacji:

2014

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

technologia ZigBee
kalibracja obszaru lokalizacji
algorytm pozycjonowania
fingerprint positioning algorithm
RSSI
ZigBee sensor networks
polynomial interpolation
particle filter

Opis:

The key to fingerprint positioning algorithm is establishing effective fingerprint information database based on different reference nodes of received signal strength indicator (RSSI). Traditional method is to set the location area calibration multiple information sampling points, and collection of a large number sample data what is very time consuming. With Zigbee sensor networks as platform, considering the influence of positioning signal interference, we proposed an improved algorithm of getting virtual database based on polynomial interpolation, while the pre-estimated result was disposed by particle filter. Experimental result shows that this method can generate a quick, simple fine-grained localization information database, and improve the positioning accuracy at the same time.
Kluczem do algorytmu pozycjonowania wykorzystującego metodę fingerprinting jest ustanowienie skutecznej bazy danych na podstawie informacji z radiowych nadajników referencyjnych przy wykorzystaniu wskaźnika mocy odbieranego sygnału (RSSI). Tradycyjna metoda oparta jest na przeprowadzeniu kalibracji obszaru lokalizacji na podstawie wielu punktów pomiarowych i otrzymaniu dużej liczby próbek, co jest bardzo czasochłonne.

Źródło:

Geodesy and Cartography; 2014, 63, 2; 219-233
2080-6736
2300-2581

Pojawia się w:

Geodesy and Cartography

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Influence of surface texture parameters on friction characteristics under starved lubrication

Autorzy:

Wu, Shen
Zhang, Pan
Wei, Haijun
Chen, Lei

Powiązania:

https://bibliotekanauki.pl/articles/259916.pdf

Data publikacji:

2020

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

marine diesel engine
cylinder liner and piston ring
friction reduction
starved lubrication
laser texturing

Opis:

A cylinder liner and piston ring running under starved lubrication near the top dead centre (TDC) and bottom dead centre (BDC) cause abnormal friction and wear during operation of a marine diesel engine. The method of laser texturing is proposed to improve the surface friction property under this condition. Spherical crown pits with different parameters were formed on the surface of samples by femtosecond laser processing. The BDC and TDC conditions of oil starvation were simulated in a reciprocating friction and wear experiment, and a numerical model of Surface texture lubrication based on the Reynolds equation was established. The influence of the distribution density, diameter, and depth parameters of the texture on the surface properties was studied. In the BDC condition, compared with the untextured surface, the average coefficient of friction (COF) can be reduced by up to 24% and the average friction force can be reduced by up to 18%. In the TDC condition, the COF can be reduced by up to 19%, and the average friction force can be reduced by up to 18%. Therefore, the textures with various parameters should be arranged in different positions on the cylinder liner; more attention should be paid to the optimisation of diameter in the texture of the cylinder liner near the BDC, whereas more attention should be paid to the optimisation of distribution density in the texture of the cylinder liner near the TDC

Źródło:

Polish Maritime Research; 2020, 2; 96-106
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Method of Structure Design and Heat Treatment of an Integrated Consolidation Sensor and Embedded Temperature Sensing Fabric
Metoda projektowania struktury zintegrowanego czujnika temperatury wbudowanego w tkaninę

Autorzy:

Zhang, R.
Deng, N.
Cheng, B.
Wu, Y.

Powiązania:

https://bibliotekanauki.pl/articles/949452.pdf

Data publikacji:

2016

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych

Tematy:

temperature sensing fabric
structure design
partial heat treatment
fabric testing
temperature value
tkanina
czujnik temperatury
częściowa obróbka cieplna
testy tkanin
wartość temperatury

Opis:

In order to solve the problem of temperature sensors easily slipping and improve the precision of temperature measurement in temperature sensing fabric, a specially designed fabric was developed. In this paper, the fabric comprised plain and multi-layered fabric. Sensors were embedded into the multi-layered fabric. The multi-layered fabric was treated by partial heat treatment to make the temperature sensors be fixed to the fabric. The temperature sensing fabrics were measured before and after the partial heat treatment. The results showed that during the heat treatment, the number of fabric layers and fabric organization had an effect on temperature measurement, and the values measured after partial heat treatment were closer to the true value than without treatment. In addition, with an increase in the number of fabric layesr, the values measured were closer to the real value. And the measurement results were closer to the true value when the multi-layered fabric’s organizational structure was plain.
Dla uzyskania hybrydowego elementu pomiarowego opracowano taką strukturę tkaniny aby móc umieścić w niej czujniki temperatury. Wielowarstwową tkaninę poddano odpowiedniej obróbce termicznej umożliwiającej zamocowanie czujników w tkaninie. Stwierdzono, że ilość warstw tkaniny i ich rozmieszczenie ma wyraźny wpływ na uzyskiwaną dokładność pomiaru temperatury. Przy zwiększeniu ilości warstw wzrastała dokładność pomiaru.

Źródło:

Fibres & Textiles in Eastern Europe; 2016, 5 (119); 68-72
1230-3666
2300-7354

Pojawia się w:

Fibres & Textiles in Eastern Europe

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Energy consumed by valves in conventional water systems and the application of a power-decentralization system

Autorzy:

Fu, Y.
Cai, Y.
Zhang, Z.
Wu, K.

Powiązania:

https://bibliotekanauki.pl/articles/1955328.pdf

Data publikacji:

2006

Wydawca:

Politechnika Gdańska

Tematy:

power-centralized system
power-decentralized system
valves' power consumption
valve

Opis:

The power consumption by valves of a conventional (i.e. power-centralized) water system is analyzed on the example of a water heating system in order to evaluate the extent of energy savings achievable in a power-decentralized system. The configuration and appli-cation of a power-decentralized system is briefly discussed.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 3; 311-320
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Time-dependent reliability analysis of corroded RC beams based on the phase-type fitting method

Autorzy:

Li, Junxiang
Chen, Jianqiao
Zhang, Xinxin
Wu, Zijun

Powiązania:

https://bibliotekanauki.pl/articles/27320977.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

chloride penetration
uncertainties
time-dependent reliability analysis
PH fitting method
corroded reinforced concretebeams

Opis:

It remains an important challenge to quantitatively describe the corrosion of reinforced concrete (RC) structures under chloride penetration. When considering the uncertainties encountered throughout the life cycle of RC structures exposed to a corrosive environment and evaluating their safety and reliability, the complexity of the problem intensifies. To address these issues, this paper focuses on the time-dependent reliability analysis of corroded RC beams, utilizing the phase-type (PH) fitting method. Initially, a model for the time-dependent reliability of corroded RC beams is established, incorporating the time-dependent chloride diffusion coefficient. Subsequently, a novel PH fitting method is proposed. The effectiveness of this new method is demonstrated through numerical examples. Furthermore, the time-dependent reliability analysis of corroded RC beams is compared using both the PH fitting method and the Monte Carlo simulation. The results reveal that the proposed method can accurately and efficiently deal with time-dependent reliability problems.

Źródło:

Eksploatacja i Niezawodność; 2023, 25, 4; art. no. 172442
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Contribution on fluid inclusion abundance to activation of quartz flotation

Autorzy:

Yuan, Y.
Zhang, L.
Guan, J.
Zhang, C.
Wu, J.
Chen, Z.

Powiązania:

https://bibliotekanauki.pl/articles/110067.pdf

Data publikacji:

2018

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

recovery
flotation
mineralogy
fluid Inclusions
fluid inclusion abundance

Opis:

In this study, comparative experiments were conducted on the recovery of quartz using flotation with different fluid inclusion abundances. A large number of fluid inclusions with various sizes have been found in natural quartz. Micrographs, inductively coupled plasma, electron probe microanalysis, homogenization temperature, Raman spectra, zeta potentials, X-ray photoelectron spectroscopy, scanning electron microscope, and energy dispersive spectrometer were used to characterize the fluid inclusions and quartz, as well as the adsorption tests and single mineral flotation experiments to investigate its floatability. The results demonstrated that it was more likely for quartz with higher fluid inclusion abundance to connect with Fe3+ sufficiently to achieve a high level of flotation recovery, due to the powerful collecting ability by sodium dodecyl sulphonate to Fe3+. Furthermore, the mechanism indicated that the adsorption between quartz and Fe3+ was a process of chemisorption.

Źródło:

Physicochemical Problems of Mineral Processing; 2018, 54, 3; 981-991
1643-1049
2084-4735

Pojawia się w:

Physicochemical Problems of Mineral Processing

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Carrollite Leaching in H2SO4-NaClO3 Media at Atmospheric Pressure

Autorzy:

Dong, Bo
Wu, Jian-Hui
Wu, Jun
Zhang, Xian-Peng
Zhai, Jing-Jun

Powiązania:

https://bibliotekanauki.pl/articles/352763.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

CuCo2S4
atmospheric leaching
H2SO4-NaClO3 media

Opis:

A new extraction process suitable for treating refractory CuCo₂S₄ under atmospheric pressure acidic leaching conditions was investigated. The effect of variables such as oxidant species, liquid-to-solid ratio, leaching time, oxidizing agent and mineral quality ratio, H₂SO₄ concentration, temperature and sodium chloride concentration on the extraction efficiency of Co, Cu and Fe from CuCo₂S₄ were investigated. Under optimal conditions including P₈₀-P₉₀ of the sample was d < 0.0074 mm, stirring speed of 400 rpm, leaching time of 8 h with sodium chlorate (NaClO₃) and mineral quality ratio of 0.5, 2 mol/L H₂SO₄, liquid-to-solid ratio of 7, leaching temperature of 90°C and 4 mol/L sodium chloride. The leaching efficiency of Co, Cu, and Fe were nearly 97.08%, 100%, and 92.45%, respectively. Furthermore, the contents of cobalt and copper in leaching residue were all less than 0.4 wt.%, which satisfies the requirements of industrial production.

Źródło:

Archives of Metallurgy and Materials; 2020, 65, 1; 313-319
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Cascading failures and maintenance optimization of urban transportation networks

Autorzy:

Dui, Hongyan
Zhang, Yulu
Chen, Liwei
Wu, Shaomin

Powiązania:

https://bibliotekanauki.pl/articles/27312781.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

reliability
maintenance optimization
cascading failures
transportation networks

Opis:

A convenient urban transportation network facilitates a high-quality life and a high-growth economy. Due to cascading failures being a ticklish question triggering continuous road congestion, the maintenance plan is momentous to restore the urban transportation network. Considering fault edges are removed and cars slowly drive out of these edges to ease traffic congestion, a traffic distribution model is proposed to analyze the cascading failures process. To resume the transportation network, this paper proposes a maintenance optimization with minimizing maintenance time. It recovers the cascading failures from two perspectives: the intra-area maintenance model and the inter-area maintenance model. At last, a transportation network of a city in China is regarded as a case study to illuminate the feasibility of the proposed models. The results show that on the premise of dividing traffic areas, it is reasonable to adopt the intra-area maintenance plan for cascading failures. Compared with the previous travel data, the inter-area maintenance plan saves more time.

Źródło:

Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 168826
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Wavelength-sensitive-function-based spectral reconstruction using segmented principal component analysis

Autorzy:

Wu, G.
Shen, X.
Liu, Z.
Zhang, J.

Powiązania:

https://bibliotekanauki.pl/articles/174199.pdf

Data publikacji:

2016

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

spectral reconstruction
wavelength-sensitive function
segmented principal component analysis

Opis:

Spectral images provide richer information than colorimetric images. A high-dimensional spectral data presents a challenge for efficient spectral reconstruction. In conventional reconstruction methods it is very difficult to obtain good spectral and colorimetric accuracy simultaneously. In this paper, a segmented principal component analysis (SPCA) method and a weighted segmented principal component analysis (wSPCA) method are proposed for efficient reconstruction of spectral color information. The methods require, firstly, partitioning the complete spectrum of wavelengths into two subgroups, considering the sensitivity of human visual system. Then the classical principal component analysis (PCA) carried out each subgroup of data separately. The results indicated that the spectral and colorimetric accuracy of the SPCA and wSPCA outperformed the PCA and weighted PCA, and wSPCA clearly retained more color visual information.

Źródło:

Optica Applicata; 2016, 46, 3; 365-374
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Variation of strata pressure and axial bolt load at a coal mine face under the effect of a fault
Zmienność ciśnienia górotworu i obciążenia osiowe działające na segmenty obudowy w rejonie przodka spowodowane obecnością uskoków

Autorzy:

Shi, Hao
Zhang, Houquan
Song, Lei
Wu, Yu

Powiązania:

https://bibliotekanauki.pl/articles/218749.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

symulacje numeryczne FLAC 3D
naprężenia osiowe działające na obudowę
zachowanie górotworu
górnictwo
efekt uskoku
model odprężania
FLAC3D numerical simulation
axial bolt load
strata behavior
mining and fault effect
strain-softening model

Opis:

The cohesion and internal friction angle were characterized as quadratic functions of strain and were assumed to follow the Mohr-Coulomb criterion after the yield of peak strength. These mechanical parameters and their variations in post-peak softening stage can be exactly ascertained through the si-multaneous solution based on the data points of stress-strain curves of triaxial compression tests. Taking the influence of the fault into account, the variation of strata pressure and roadway convergence with coal advancement, the temporal and spatial distribution of axial bolt load were numerically simulated by FLAC3D (Fast Lagrangian Analysis of Continua) using the ascertained post-peak mechanical parameters according to the cohesion weakening and friction strengthening model. The change mechanism of axial load of single rock bolt as abutment pressure changes was analyzed, through the comparison analysis with the results of axial bolt load by field measurements at a coal mine face. The research results show that the simulated results such as the period of main roof weighting, temporal and spatial distribution of axial bolt load are in accordance with field measurement results, so the validity of the numerical model is testified. In front of the working face, the front abutment pressure increases first and then decreases, finally tends to be stable. A corresponding correlation exists between the variation of axial bolt load and rock deformation along the bolt body. When encountered by a fault, the maximum abutment pressure, the influential range of mining disturbance and the roadway convergence between roof and floor before the working face are all increased. In the roadways along the gob, axial bolt loads on the side of the working face decrease, while the other side one increases after the collapse of the roof. As superficial surrounding rock mass is damaged, the anchoring force of rock bolts will transfer to inner rock mass for balancing the tensile load of the bolts.
Zwięzłość skał oraz kąt tarcia wewnętrznego zdefiniowano jako kwadratowe funkcje naprężenia, następnie przyjęto że ich rozkład po osiągnięciu naprężenia granicznego opisany jest wzorem Mohra-Coulomba. Wymienione parametry mechaniczne i ich zmienność po osiągnięciu naprężenia granicznego obliczyć można dokładnie poprzez jednoczesne rozwiązanie oparte o analizę punktów na krzywej wykresu rozciągania uzyskanych w testach ściskania trójosiowego. Uwzględniając wpływ obecności uskoku, zmienność ciśnienia w górotworze i konwergencji chodnika wraz z postępem przodka, rozkłady naprę-żeń i obciążeń działających na segmenty obudowy i ich zmienność w czasie i przestrzeni modelowano w oparciu o pakiet FLAC3D (Fast Lagrangian Analysis of Continua), wykorzystując uprzednio obliczone wielkości parametrów mechanicznych dla stanu po osiągnięciu naprężenia granicznego, zgodnie z mo-delem słabnącej zwięzłości i wzmocnionego tarcia. Mechanizm zmiany naprężeń osiowych działających na pojedynczy segment obudowy analizowano w odniesieniu do ciśnienia warstw sąsiadujących, poprzez analizę porównawczą wyników pomiarów obciążeń segmentów obudowy w rejonie przodka. Wykazano, że wyniki symulacji: okresy obciążenia stropu, rozkłady naprężeń i obciążeń działających na elementy obudowy i ich zmienność w czasie i przestrzeni zgodne są z wynikami pomiarów w miejscu, w ten sposób potwierdzając wiarygodność modelu numerycznego. W rejonie przodka ciśnienie warstw sąsiadujących w górotworze najpierw rośnie, następnie maleje, a w końcu stabilizuje się. Istnieje odpowiednia korelacja pomiędzy zmiennością rozkładu naprężeń i obciążeń działających na elementy obudowy a odkształceniem warstw skalnym wzdłuż konstrukcji obudowy. W przypadku wystąpienia uskoku, występuje maksymalne ciśnienie warstw otaczających- poważny czynnik powodujący wszelkiego rodzaju zaburzenia a także nasilenie konwergencji chodnika pomiędzy stropem a podłożem w rejonie przed przodkiem. W chodnikach wzdłuż zrobów, obciążenia osiowe obudowy działające z jednej strony maleją, po drugiej zaś stronie rejonu przodkowego rosną po zawale stropu. Płytka warstwa otaczającego górotworu ulega zniszczeniu, siła podtrzymująca obudowę przeniesiona zostanie wewnątrz górotworu, tak by zrównoważyć naprężenia rozciągające działające na obudowę.

Źródło:

Archives of Mining Sciences; 2019, 64, 2; 351-374
0860-7001

Pojawia się w:

Archives of Mining Sciences

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 29.

Tytuł:

Analysis of the dynamic response of offshore floating wind power platforms in waves

Autorzy:

Li, Junlai
Xie, Yonghe
Wu, Weiguo
Zhang, Chi

Powiązania:

https://bibliotekanauki.pl/articles/1573800.pdf

Data publikacji:

2020

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

floating wind power platform
dynamic response
inherent laws
numerical calculation
tank test

Opis:

Floating wind power platforms are in constant motion due to waves when deployed at sea. This motion directly affects the stability and safety of the platform. Therefore, it is very important to study the laws governing the platform’s dynamic response. In this paper, the dynamic characteristics of an offshore floating wind power platform were analysed under nine different sets of operating conditions using a numerical calculation method. Following this, a scaled 1:50 platform model was tested in a tank. Model tests were carried out with different wave conditions, and dynamic response data for the platform were measured and analysed. The hydrodynamic variation rules of floating wind power generation platform in waves were obtained. Some effective measures for maintain the stability and safety of wind power platforms are put forward that can provide a reference for dynamic stability research and the design of floating wind power platforms in the future.

Źródło:

Polish Maritime Research; 2020, 4; 17-25
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Investigations on the Anisotropic g Factors of the $Ni^{3+}$ Site in $La_2Ni_{0.5}Li_{0.5}O_4$

Autorzy:

Kuang, M.
Wu, S.
Zhang, Z.
Song, B.

Powiązania:

https://bibliotekanauki.pl/articles/1400149.pdf

Data publikacji:

2013-04

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

76.30.Fc
71.70.Ch
75.10.Dg

Opis:

The anisotropic g factors $g_{∥}$ and $g_{⊥}$ of $La_2Ni_{0.5}Li_{0.5}O_4$ are theoretically investigated using the perturbation formulae of the g factors for a low spin $(S=1//2) 3d^7$ ion in tetragonally elongated octahedra. The studied $Ni^{3+} (3d^7)$ center arises from the original $Ni^{2+}$ capturing one hole by $Li^{+}$ doping. The positive anisotropy $\Delta g (= g_{⊥}-g_{∥})$ can be ascribed to the lowest $\text{}^2 A_{1g}$ state due to the obvious (about 0.14 Å) tetragonal elongation of the oxygen octahedron around the $Ni^{3+}$ site via the Jahn-Teller effect, and the effective magnetic moment is also interpreted in a uniform way. The calculated results show good agreement with the experimental data, and the imperfection of the previous studies based on various adjusted tetragonal energy splittings without correlating to the local structure of the magnetic center is thus overcome in this work.

Źródło:

Acta Physica Polonica A; 2013, 123, 4; 734-736
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

A delay reliability estimation method for Avionics Full Duplex Switched Ethernet based on stochastic network calculus
Oparta na stochastycznym rachunku sieciowym metoda estymacji niezawodności czasu transmisji dla przełączanej pokładowej sieci ethernetowej typu AFDX umożliwiającej równoczesną transmisję dwukierunkową

Autorzy:

Wu, Z.
Huang, N.
Li, R.
Zhang, Y.

Powiązania:

https://bibliotekanauki.pl/articles/301884.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

reliability estimation
delay upper bound
stochastic network calculus
traffic envelope function
ocena niezawodności
górna granica opóźnienia
stochastyczny rachunek sieciowy
funkcja obwiedni ruchu telekomunikacyjnego

Opis:

The delay reliability estimation is required in order to guarantee the real-time communication for avionics full duplex switched Ethernet (AFDX). Stochastic network calculus (SNC) can be applied to estimate the reliability with a delay upper bound. However, only linear deterministic traffic envelope function is used to bound its traffic, which cannot represent the traffic randomness and is far from practice. In this paper, a stochastic traffic envelope function, which randomizes the input of SNC, is proposed to solve the problem. A new probabilistic algorithm is derived to estimate the delay reliability based on stochastic envelope functions. A test was conducted to demonstrate our method on an AFDX testbed, and the test results verify that the estimation of delay reliability via our algorithm is much closer to the empirical estimation.
Ocena niezawodności czasu transmisji (czasu opóźnienia) jest niezbędną procedurą gwarantującą komunikację w czasie rzeczywistym za pośrednictwem przełączanej pokładowej sieci ethernetowej typu AFDX (Avionics Full Duplex Switched Ethernet), która umożliwia równoczesną transmisję dwukierunkową. Stochastyczny rachunek sieciowy (SNC) można stosować do oceny niezawodności przy zadanej górnej granicy opóźnienia. Do tej pory jednak, do ograniczania ruchu telekomunikacyjnego stosowano tylko liniową deterministyczną funkcję obwiedni (traffic envelope), która nie oddaje losowości ruchu telekomunikacyjnego i odbiega dalece od rzeczywistości. W niniejszej pracy zaproponowano rozwiązanie tego problemu wykorzystujące stochastyczną funkcję obwiedni ruchu telekomunikacyjnego. Wyprowadzono nowy algorytm probabilistyczny, który pozwala ocenić niezawodność czasu transmisji na podstawie funkcji obwiedni. Przeprowadzono badanie, w ramach którego testowano zaproponowaną metodę w środowisku testowym AFDX; wyniki testu pokazują, że ocena niezawodności czasu transmisji z wykorzystaniem zaproponowanego przez nas algorytmu jest znacznie bardziej zbliżona do estymacji empirycznej.

Źródło:

Eksploatacja i Niezawodność; 2015, 17, 2; 288-296
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

Study on striking ship with loading impact on the performance of the double hull oil tanker collision

Autorzy:

Wu, W.
Yang, Y.
Zhang, J.
Lu, J.

Powiązania:

https://bibliotekanauki.pl/articles/258890.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

ship collision
fluid-structure interaction
impact parameters
numerical simulation

Opis:

Due to the great danger of the collision of oil tankers, lots of research on the collision of oil tankers has been carried out. But, at present, the research on the collision of oil tankers mainly focuses on the loading condition of the struck ship, ignores the impact on the loading condition of the striking ship. However, during the actual oil tanker collision, the striking ship is generally in the state of loading. Therefore, it is necessary to carry out the analysis of the impact of the loading condition of the striking ship on the collision damage of the oil tanker. In this paper, the effect of striking ship with loading on the impact performance of the side structure during the collision of the cargo double hull oil tanker has been investigated. The ship collision model was established by using the finite element software ANSYS/ LS-DYNA which is based on 7000 tons of double hull oil tankers. Based on the analysis of the collision force, impact of striking speed changes, impact of striking deep changes and structural energy absorption during the collision process, the influence of the striking ship with loading on the damage mechanism and the impact performance of the double shell oil ship side structure was expounded. The results show that the influence of the striking ship with loading can be great to the damage to side hull during the research of the collision performance of the oil tanker.

Źródło:

Polish Maritime Research; 2018, S 2; 42-48
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Numerical study on compression properties of semi-reentrant filled tubular structures

Autorzy:

Wu, Dongquan
Li, Dinghe
Zhang, Zhiqiang
Chen, Jianguo

Powiązania:

https://bibliotekanauki.pl/articles/2200883.pdf

Data publikacji:

2023

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

semi-reentrant (SR) structure
tubular fillers
out-of-plane
in-plane compression

Opis:

In this study, a semi-reentrant structure (SR) filled with different tubular structures, includ- ing tube, triangular and rectangle structures were designed. The tubular structures were perfectly assembled into semi-reentrant cells to avoid swaying in the semi-reentrant cell. The geometric relations and relative density for these structures were established. For the out-of-plane and in-plane compressions, SR filled tubular structures exhibited different de- formation patterns compared to those of SR or pure fillers. A constraint effect was found between the filler tubular and container SR. With fillers contained inside the SR structures, the plateau stresses for three conditions were all promoted compared to those of SR. The best out-of-plane compression resistance occurred in the SR filled rectangle which might be caused by larger interaction areas between the SR and rectangular structures. The (specific) energy absorption of the SR filled tube compressed out-of-plane was the largest. The peak and plateau stress of the SR filled triangle was the largest compared to other structures when compressed in plane due to stability of the triangle. It was found that the plateau stress, energy absorption and specific energy absorption of SR filled triangle was the largest, while that of SR filled rectangle was the lowest.

Źródło:

Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 233--244
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

A fault diagnosis method for substation grounding grid based on the square-wave frequency domain model

Autorzy:

Zhang, P.-H.
He, J.-J.
Zhang, D.-D.
Wu, L.-M.

Powiązania:

https://bibliotekanauki.pl/articles/221635.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

square-wave
frequency characteristics
grounding grid
fault diagnosis

Opis:

Current methods of fault diagnosis for the grounding grid using DC or AC are limited in accuracy and cannot be used to identify the locations of the faults. In this study, a new method of fault diagnosis for substation grounding grids is proposed using a square-wave. A frequency model of the grounding system is constructed by analyzing the frequency characteristics of the soil and the grounding conductors into which two different frequency square-wave sources are injected. By analyzing and comparing the corresponding information of the surface potentials of the output signals, the faults of the grounding grid can be diagnosed and located. Our method is verified by software simulation, scale model experiments and field experiments.

Źródło:

Metrology and Measurement Systems; 2012, 19, 1; 63-71
0860-8229

Pojawia się w:

Metrology and Measurement Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Fatigue reliability analysis of the brake pads considering strength degradation

Autorzy:

Zhang, Nan
Jiang, Guang-Jun
Wu, Dong-Wei
Chen, Hong-Xia
Wu, Jian-Xin

Powiązania:

https://bibliotekanauki.pl/articles/1841941.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

stress-strength interference model
dynamic reliability
strength degradation
impact load

Opis:

Reliability prediction of the brake pads is indispensable to guarantee their safety. In the paper, the fatigue reliability of brake pads is analyzed by dynamic stress-strength interference (SSI) model considering strength degradation. Firstly, reliability model of the brake pads was established based on stress-strength interference model considering the influence of impact load. Then reliability of the brake pads was predicted under different impact load frequency and initial strength. Finally, the influence of random degradation strength on reliability was studied by contrast. The analysis results show that random strength degradation, impact load and initial strength have great influence on reliability prediction for the brake pads. Therefore, the reliability prediction of the brake pads fatigue strength considering strength degradation is more in line with the actual situation and the calculation accuracy is higher.

Źródło:

Eksploatacja i Niezawodność; 2020, 22, 4; 620-626
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Feasibility study of RANS in predicting propeller cavitation in behind-hull conditions

Autorzy:

Zhang, Yuxin
Wu, Xiao-ping
Lai, Ming-yan
Zhou, Guo-ping
Zhang, Jie

Powiązania:

https://bibliotekanauki.pl/articles/1573849.pdf

Data publikacji:

2020

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

RANS
Computational Fluid Dynamics (CFD)
propeller cavitation
turbulence model
grid sensitivity

Opis:

The propeller cavitation not only affects the propulsive efficiency of a ship but also can cause vibration and noise. Accurate predictions of propeller cavitation are crucial at the design stage. This paper investigates the feasibility of the Reynolds-averaged Navier–Stokes (RANS) method in predicting propeller cavitation in behind-hull conditions, focusing on four aspects: (i) grid sensitivity; (ii) the time step effect; (iii) the turbulence model effect; and (iv) ability to rank two slightly different propellers. The Schnerr-Sauer model is adopted as the cavitation model. A model test is conducted to validate the numerical results. Good agreement on the cavitation pattern is obtained between the model test and computational fluid dynamics. Two propellers are computed, which have similar geometry but slightly different pitch ratios. The results show that RANS is capable of correctly differentiating the cavitation patterns between the two propellers in terms of the occurrence of face cavitation and the extent of sheet cavitation; moreover, time step size is found to slightly affect sheet cavitation and has a significant impact on the survival of the tip vortex cavitation. It is also observed that grid refinement is crucial for capturing tip vortex cavitation and the two-equation turbulence models used – realizable k-ε and shear stress transport (SST) k-ω – yield similar cavitation results.

Źródło:

Polish Maritime Research; 2020, 4; 26-35
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Preparation, Structure and Kinetic Analysis of the Thermal Behavior of Some Energetic Salts of 3-Hydrazino-4-amino-1,2,4-triazole

Autorzy:

Wu, J. T.
Zhang, J. G.
Sun, M.
Yin, X.
Zhang, T. L.

Powiązania:

https://bibliotekanauki.pl/articles/358073.pdf

Data publikacji:

2013

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

synthesis
crystal structure
thermal analysis
3-hydrazino-4-amino-1,2,4-triazole
energetic salts

Opis:

As a key research objective for low melting explosives and propellants, energetic salts have received worldwide attention. 3-Hydrazino-4-amino-1,2,4triazole (HATr) is an important high-nitrogen compound (73.65% N) with good stability. This paper focuses on the energetic salts which were formed between HATr and picric acid (PA) or 2,4,6-trinitroresorcinol (TNR). Single crystals of HATr·PA and HATr·TNR·H2O were grown and their crystal structures determined at low temperature. They both belong to the monoclinic system, P21/n space group. The thermal characteristics of the two target salts were investigated using DSC and TG-DTG. In addition, the non-isothermal decomposition kinetics, heats of combustion and sensitivity have also been investigated. The detonation pressures (P) and detonation velocities (D) of the salts have been calculated using the K-J equations. The results indicated that both salts have certain potential applications as gunpowder and propellant materials.

Źródło:

Central European Journal of Energetic Materials; 2013, 10, 4; 481-493
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Modification Mechanism and Growth Process of Al₃(Sc, Zr) Particles in As-cast Al-Si-Mg-Cu-Zr-Sc Alloy

Autorzy:

Li, Y.
Du, X.
Fu, J.
Zhang, Y.
Zhang, Z.
Zhou, S.
Wu, Y.

Powiązania:

https://bibliotekanauki.pl/articles/382672.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

solidification process
Al3(Sc, Zr)
three-dimensional morphology
eutectic growth
krzepnięcie stopu
morfologia trójwymiarowa
wzrost eutektyczny

Opis:

In this study, the modification mechanism and growth process of Al₃(Sc, Zr) particles in as-cast Al-Si-Mg-Cu based alloy with addition of Sc and Zr were systematically investigated. It was found that 0.57 wt-%Sc addition caused a significant refinement in the average grain size of the investigated alloy, which brought about a remarkable transformation in as-cast microstructure, from thick dendritic shape to fine equiaxed structure. A large amount of primary Al₃(Sc, Zr) particles with the dimension of around 5-6 μm were also observed within the equiaxed grain. Due to the identical orientation and similar crystal structure between primary Al₃(Sc, Zr) particles and α-Al matrix, the primary particles always served as heterogeneous nucleus for the α-Al matrix. In addition, these cusped cubic primary Al₃(Sc, Zr) particles showed triangle, star, rhomboid morphologies are generated from sectioning the particle in (111), (100) and (110) planes, respectively. Particularly, the typical eutectic structure which contained odd number-layer (Al₃(Sc, Zr)+α-Al+ ... +Al₃(Sc, Zr)) was observed within the investigated particles.

Źródło:

Archives of Foundry Engineering; 2018, 18, 2; 51-56
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Study on optimization simulation of SCR denitration system for marine diesel engine

Autorzy:

Du, J.
Li, R. N.
Wu, X.
Zhang, Y.

Powiązania:

https://bibliotekanauki.pl/articles/259646.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

marine diesel engine
SCR system
flue gas
flow deflector

Opis:

With the rapid development of shipbuilding industry exhaust world is also very harmful one kind of environmental issues, and the ship marine diesel engine exhaust gas is mainly produced, so in recent years it has developed a diesel engine SCR system. SCR system can control emissions of nitrogen oxides in the exhaust of vessel, furthermore air pollution can be reduced. The main goal of article was using fluent software to correct SCR system selection and flue gas flow under different size best deflector arrangement is simulated. Next goal is further optimize the structure of the SCR system.

Źródło:

Polish Maritime Research; 2018, S 3; 13-21
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Concave and convex effects of ESG performance on corporate sustainable development: Evidence from China

Autorzy:

Zhang, XueHui
Miao, Le
Mu, Guoying
Wu, Kun-Shan

Powiązania:

https://bibliotekanauki.pl/articles/39992737.pdf

Data publikacji:

2024

Wydawca:

Instytut Badań Gospodarczych

Tematy:

ESG
corporate sustainable development
quantile regression
double-edged effect

Opis:

Research background: Corporate sustainable development (CSD) is essential to a company's success and survival. Environmental, social, and governance (ESG) are regarded as major factors in measuring the impact of CSD. Companies that perform well in terms of ESG can maintain a competitive advantage and achieve sustainable development. Poor management of ESG performance and involvement in controversial activity can harm a company's credibility and reputation in the market, as well as negatively impact sustainable development. Purpose of the article: Drawing on the stakeholder and signaling theories, this paper investigates the curvilinear nexus between ESG performance and CSD. Methods: Empirical studies were conducted on a sample of 697 Chinese listed manufacturing firms that disclosed ESG information from 2010 to 2020, with a total of 5699 firm-year observations. Quantile regression analysis and the U-test were used to examine the curvilinear ESG-CSD relationship. This technique was supplemented by conducting instrumental variables tests and propensity score matching to address concerns relating to the potential existence of endogeneity problems. Findings & value added: The results of the quantile regression estimation confirm the concave-convex (inverted U-shaped and U-shaped) ESG-CSD relationship via the U-test. The relationships between the environmental and social components and CSD follow an inverted U-shaped or half-inverted U-shaped pattern, while the relationship between the governance component and CSD exhibits a concave-convex pattern. A concave ESG-CSD nexus is evident in environmentally sensitive industries, whereas a half concave-convex ESG-CSD nexus is confirmed in non-environmentally sensitive industries. This study improves scholars’ understanding of ESG performance and provides a comprehensive perspective on the double-edged effects (positive and negative consequences) of ESG practices. The instrumentalization of ESG practices for management to seek personal gain has a negative impact on CSD, while ESG practices that add value for stakeholders have a positive impact. These findings provide empirical evidence for Chinese publicly listed manufacturing firms to effectively conduct ESG practices.

Źródło:

Oeconomia Copernicana; 2024, 15, 2; 595-636
2083-1277

Pojawia się w:

Oeconomia Copernicana

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

A comprehensive cycloid pin-wheel precision reducer test platform integrated with a new dynamic measurement method of lost motion

Autorzy:

Yue, Huijun
Wu, Xiangkai
Shi, Zhaoyao
Zhang, Yue
Ye, Yong
Zhang, Lintao
Fu, Ying

Powiązania:

https://bibliotekanauki.pl/articles/2052087.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

cycloid pin-wheel precision reducer
RV reducer
test platform
comprehensive performance
dynamic measurement of lost motion
decomposition test method

Opis:

While cycloid pin-wheel precision reducers (referred to as RV reducers) are widely used in industrial robots, a widely accepted design standard or verification method of their test platforms is not available. In this study, a comprehensive sliding-separation test platform of RV reducers was developed. The test platform can test various measurement items such as transmission error, static measurement of lost motion, dynamic measurement of lost motion, torsional rigidity, no-load running torque, starting torque, backdriving torque, and transmission efficiency of the RV reducer for robots. The principle and method of dynamic measurement of lost motion tests based on the two-way transmission error method were studied and this test function was successfully integrated with the comprehensive test platform in order to increase the test items of the dynamic performance parameters of RV reducers. The measurement results of the no-load running torque of the RV reducer were consistent with the Stribeck curve. Based on the concept of optimal measurement speed, a decomposition test method of the geometric component of the dynamic measurement of lost motion and the elastic component of the dynamic measurement of lost motion was proposed in the dynamic measurement test of lost motion. Through precision calibration, function test and repeatability test, the results were compared with the data of enterprise’s samples. The consistent results have proved that the test platform met engineering requirements and measurement accuracy requirements. Based on the new test principle, the developed platform can test more parameters of RV reducers with high precision and display the comprehensive test performance.

Źródło:

Metrology and Measurement Systems; 2022, 29, 1; 207-229
0860-8229

Pojawia się w:

Metrology and Measurement Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

Influence of Wave-Absorbing Functional Particles on the Electromagnetic Properties and Mechanical Properties of Coated Composites for Nickel Powders
Wpływ absorbujących fale cząstek funkcyjnych na właściwości elektromagnetyczne i mechaniczne kompozytów powlekanych żywicą poliuretanową zawierającą proszek niklu

Autorzy:

Liu, Yuanjun
Wang, Yi
Wu, Xiang
Zhang, Lulu
Niu, Jiarong

Powiązania:

https://bibliotekanauki.pl/articles/233612.pdf

Data publikacji:

2020

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych

Tematy:

nickel powder
single-layer coating
electromagnetic shielding
dielectric properties
proszek niklowy
powłoka jednowarstwowa
ekranowanie elektromagnetyczne
właściwości dielektryczne

Opis:

In this subject, a single-layer coated composite for nickel powders was prepared using PU2540 polyurethane as the matrix, nickel powder as the wave-absorbing functional particle, and coating technology on plain cotton fabric. The influence of wave-absorbing functional particles on the dielectric, shielding effectiveness and mechanical properties of the single-layer coated composite for nickel powders was mainly analysed and compared. Results showed that the real and imaginary parts and loss tangent of the dielectric constant were all the largest when the iron powder was mixed with the nickel powder, and its polarizing ability, loss ability and attenuation ability with respect to electromagnetic waves were all the maximum. When the graphene was mixed with the nickel powder, the shielding attenuation ability with respect to electromagnetic waves was the best.
W ramach pracy przygotowano jednowarstwowy kompozyt powlekany żywicą poliuretanową zawierającą proszek niklu. Do przygotowania kompozytów użyto poliuretanu PU2540 jako matrycy i proszku niklu jako absorbującej fale cząstki funkcjonalnej oraz zastosowano technologię powlekania na gładkiej tkaninie bawełnianej. Przeanalizowano i porównano głównie wpływ absorbujących fale funkcjonalnych cząstek na dielektryk, skuteczność ekranowania i właściwości mechaniczne jednowarstwowego powlekanego kompozytu. Wyniki pokazały, że rzeczywiste i urojone części oraz styczna strat stałej dielektrycznej były największe, gdy proszek żelaza został zmieszany z proszkiem niklu, a jego zdolność polaryzacyjna, zdolność do strat i zdolność tłumienia fal elektromagnetycznych były maksymalne. Gdy grafen został zmieszany z proszkiem niklu, zdolność tłumienia ekranowania fal elektromagnetycznych była najlepsza.

Źródło:

Fibres & Textiles in Eastern Europe; 2020, 5 (143); 75-81
1230-3666
2300-7354

Pojawia się w:

Fibres & Textiles in Eastern Europe

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Speech Enhancement Based on the Multi-Scales and Multi-Thresholds of the Auditory Perception Wavelet Transform

Autorzy:

Tao, Z.
Zhao, H. M.
Zhang, X-J.
Wu, D.

Powiązania:

https://bibliotekanauki.pl/articles/177021.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

speech enhancement
low SNR
auditory perception wavelet transform
unvoiced enhancement
masking effect

Opis:

This paper proposes a speech enhancement method using the multi-scales and multi-thresholds of the auditory perception wavelet transform, which is suitable for a low SNR (signal to noise ratio) environment. This method achieves the goal of noise reduction according to the threshold processing of the human ear’s auditory masking effect on the auditory perception wavelet transform parameters of a speech signal. At the same time, in order to prevent high frequency loss during the process of noise suppression, we first make a voicing decision based on the speech signals. Afterwards, we process the unvoiced sound segment and the voiced sound segment according to the different thresholds and different judgments. Lastly, we perform objective and subjective tests on the enhanced speech. The results show that, compared to other spectral subtractions, our method keeps the components of unvoiced sound intact, while it suppresses the residual noise and the background noise. Thus, the enhanced speech has better clarity and intelligibility.

Źródło:

Archives of Acoustics; 2011, 36, 3; 519-532
0137-5075

Pojawia się w:

Archives of Acoustics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 44.

Tytuł:

Laser Power Transmission and Its Application in Laser-Powered Electrical Motor Drive: A Review

Autorzy:

Liu, Hongzuo
Zhang, Yixuan
Hu, Yihua
Tse, Zion
Wu, Jing

Powiązania:

https://bibliotekanauki.pl/articles/1955981.pdf

Data publikacji:

2021

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

laser power transmission
photovoltaic material
laser diode
optical fibre power transmission
atmosphere transmission

Opis:

Laser power transmission (LPT) is considered a potentially efficient way for power delivery, especially in long-distance wireless applications and harsh hazardous environmental conditions. In contrast to other wireless power transmission (WPT) methods, LPT has many advantages such as lower device size, focused transmitting direction and high power density. With the development of technology, LPT has been widely adopted in several fields. In conservative industries, the utilisation of LPT can resolve the limitation problem in a wired connection. The adverse influence of electromagnetic interference (EMI) concerning application and high-temperature fields can be reduced. This paper will give a simple review of LPT and demonstrate the basic concept of a photoelectric emitter, transmission channel and receiver material. Based on the recent research about diode laser beam combining technology and high-efficiency multi-junction photovoltaics (PV) materials, the advised LPT devices for simple application as laser power motor will be simply discussed.

Źródło:

Power Electronics and Drives; 2021, 6, 41; 167-184
2451-0262
2543-4292

Pojawia się w:

Power Electronics and Drives

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 45.

Tytuł:

Compressive deformation characteristics of crushed sandstone based on multiple experimental factors

Autorzy:

Sun, Yanan
Zhang, Peisen
Yan, Wei
Yan, Fenqian
Wu, Junda

Powiązania:

https://bibliotekanauki.pl/articles/219794.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

mechanika skał
skały kruche
odkształcenie
rock mechanics
saturated graded crushed rock
compressive deformation
cyclic loading
cyclic unloading

Opis:

In this study, the compressive deformation of crushed sandstone was tested using a crushed rock deformation-seepage test system, and the effects of various factors, including crushed rock grade, grade combination, water saturation status, and stress loading method (i.e., continuous loading or cyclic loading and unloading), on the compressive deformation of crushed sandstone was analyzed from four perspectives including stress-strain, bulking coefficient, deformation mechanism and energy dissipation. The results indicate that the stress-strain relations of crushed sandstone are closely associated with all factors considered, and are well represented by exponential functions. The strain observed for a given applied stress increased with increasing crushed rock grade throughout the loading period. Crushed sandstone grades were combined according to a grading index (n), where the proportion of large-grade rocks in the sample increased with increasing n. The bearing capacity of a water-saturated crushed sandstone sample with n = 0.2 was less than that of an equivalent dry sample for a given applied stress. The stress-strain curve of a water-saturated crushed sandstone sample with n = 0.2 under cyclic loading and unloading was similar to that obtained under continuous loading. Observation and discovery, the deformation mechanism of crushed sandstone was mainly divided into four stages, including crushing, rupture, corner detachment and corner wear. And 20% of the work done by testing machine is used for friction between the crushed sandstone with the inner wall of the test chamber, and 80% is used for the closing of the void between the crushed sandstone, friction sliding, crushing damage.

Źródło:

Archives of Mining Sciences; 2020, 65, 1; 129-146
0860-7001

Pojawia się w:

Archives of Mining Sciences

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 46.

Tytuł:

High drilling methane drainage in fracturing zones formed by water injection into boreholes
Odprowadzania metanu metodą odwiertów dokonywanych w strefie szczelin powstałych wskutek wprowadzania wody do otworów

Autorzy:

Wang, G.
Huang, W.
Sun, L.
Wu, M.
Zhang, X.

Powiązania:

https://bibliotekanauki.pl/articles/220166.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

odwierty
odprowadzenie metanu
wtrysk wody
szczelinowanie
odkształcenia
high drilling
methane drainage
water injection
fracturing zones
strain

Opis:

Methane drainage method should be used before coal mining of many modern collieries because venti lation air methane is in sufficient to keep methane level within regulation values. The technology of high drilling methane drainage (HDMD) has been used for methane drainage although its effect is not very stable due to parameter design. The height of the fracturing zones is determined mostly according to empirical formula, on-site observation and numerical simulation analysis. In this paper, a method was introduced for determining the height of the air f ract uring zones (AFZs) based on its high similarity to the characteristics of Fracturing zones and the relationship between the height of Fracturing zones and the strain of overl ying rock strata. The application of water injection in both Shuangdingshan and Dongrong collieries found that the theoretically calculated the height of the Fracturing zones was approximately equal to the measured one in field tests within a permissible error of less than 5%, proving that the method is feasible. Based on the designed drainage parameters, the u tilization of HDMD technology in the collieries mentioned above found that the methane concentrations in both tail gate and upper corner were controlled in the ranges of 0.17% to 0.32% and 0.26% to 0.84%, respectively. These results showed that the water injection verified HDMD in Fracturing zones could effectively solve the problem of metha ne overrun and also verified the accuracy and reliability of its related theory.
Przed rozpoczęciem wydobycia węgla w wielu obecnie eksploatowanych kopalniach wskazane jest odprowadzenie metanu, ponieważ stosowane systemy wentylacji powietrza są niewystarczające aby utrzymać stężenia metanu na dopuszczalnym poziomie. Technologia odprowadzania metanu metodą odwiertów prowadzonych na różnej wysokości (HDMD) wykorzystywana jest w tym celu, choć jej wyniki nie zawsze są stabilne ze względu na konieczność doboru parametrów obliczeniowych. Wysokość strefy szczelinowania określa się zazwyczaj empirycznie, na podstawie obserwacji w terenie oraz drogą symulacji numerycznych. W pracy tej określono wysokość strefy wykonania szczelin w oparciu o podobieństwo do charakterystyk Strefy szczelinowania oraz o analizę odkształceń warstw nadkładu. Zastosowano wtrysk wody w kopalniach Shuangdingshan i Dongrong i stwierdzono, że teoretycznie obliczona wysokość stref szczelinowania była w przybliżeniu równa wysokości zmierzonej empirycznie w trakcie badań terenowych, z dopuszczalnym poziomem błędu poniżej 5%, co wskazuje na możliwość zastosowania metody. W oparciu o parametry obliczeniowe stwierdzono, że zastosowanie metody HDMD w wyżej wymienionych kopalniach spowodowało, że stężenia metanu rejestrowane w chodniku nadścianowym i górnych narożach utrzymywały się odpowiednio na poziomie 0.17%, 0.32% i 0.26%-0.84%. Wyniki te pokazują, że wtrysk wody w strefie szczelin pomaga skutecznie rozwiązać problem obecności zbyt wysokich ilości metanu, ponadto potwierdza dokładność i wiarygodność teorii na której metoda jest oparta.

Źródło:

Archives of Mining Sciences; 2016, 61, 1; 137-156
0860-7001

Pojawia się w:

Archives of Mining Sciences

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 47.

Tytuł:

Dissolution kinetics of hemimorphite in methane sulfonic acid

Autorzy:

Zhang, Qian
Wen, Shuming
Feng, Qicheng
Nie, Wenlin
Wu, Dandan

Powiązania:

https://bibliotekanauki.pl/articles/110482.pdf

Data publikacji:

2019

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

hemimorphite
methane sulfonic acid
dissolution
kinetics

Opis:

Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.

Źródło:

Physicochemical Problems of Mineral Processing; 2019, 55, 1; 1-9
1643-1049
2084-4735

Pojawia się w:

Physicochemical Problems of Mineral Processing

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 48.

Tytuł:

Virtual synchronous generator frequency response study of energy computing and storage devices

Autorzy:

Zhang, Baoge
Ping, Shanyan
Long, Yi
Jiao, Yuemin
Wu, Boxiang

Powiązania:

https://bibliotekanauki.pl/articles/2172798.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

damping coefficient
energy storage capacit
inertia coefficient
virtual synchronous machine

Opis:

Renewable energy sources are connected to the grid through inverters, resulting in reduced grid inertia and poor stability. Traditional grid-connected inverters do not have the function of voltage and frequency regulation and can no longer adapt to the new development. The virtual synchronous generator (VSG) has the function of voltage and frequency regulation and has more outstanding advantages than the traditional inverter. Based on the principle of the VSG, the relationship between energy storage capacity, frequency response and output power of the VSG is derived, and the relationship between the virtual inertia coefficient, damping coefficient and frequency characteristics of the VSG and output power is revealed. The mathematical model is established and modeled using the Matlab/Simulink simulation software, and the simulation results verify the relationship between energy storage capacity and frequency response and the output power of the VSG.

Źródło:

Archives of Electrical Engineering; 2022, 71, 4; 895--907
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 49.

Tytuł:

Research on topology of a novel three-phase four-leg fault-tolerant NPC inverter

Autorzy:

Zhang, Baoge
Ping, Shanyan
Long, Yyi
Jiao, Yyuemin
Wu, Bboxiang

Powiązania:

https://bibliotekanauki.pl/articles/2086722.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

fault tolerant operation
midpoint potential equilibrium
NPC inverter
topology reconstruction

Opis:

Diode neutral point clamped (NPC) three-level converters have been widely used in recent years. Aiming at the problems of the high device failure rate and unstable neutral point potential of NPC three-level converters, an NPC three-level circuit with fourth bridge arm redundancy is proposed based on the traditional NPC three-level converter. The redundant fourth bridge arm is used to realize the function of stabilizing voltage when there is no fault and replacing the fault half-bridge arm to maintain the continuous operation of the converter when there is a fault. By analyzing the working principle of space vector pulse width modulation (SVPWM) and the power loss of the switch, it is of particular significance to the design and control of NPC three-level converters in the future. Matlab/Simulink verifies the feasibility of the fault-tolerant circuit structure.

Źródło:

Archives of Electrical Engineering; 2022, 71, 2; 489--506
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 50.

Tytuł:

Purification and Characterization of a Low Molecular Weight Neutral Non-Starch Polysaccharide from Panax ginseng by Enzymatic Hydrolysis

Autorzy:

Ying, Ying
Ma, Chao
Zhang, Yajie
Li, Xiaoping
Wu, Hongxin

Powiązania:

https://bibliotekanauki.pl/articles/16538536.pdf

Data publikacji:

2023-02-21

Wydawca:

Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie

Tematy:

ginseng polysaccharide
chromatographic separation
monosaccharide composition
structure analysis

Opis:

In this study, a novel neutral non-starch polysaccharide (GP1A) was extracted using hot water from ginseng roots. Chemical characteristics, monosaccharide compositions and structure of GP1A were investigated using scanning electron microscopy, gel permeation chromatography, X-ray diffraction, Fourier transform infrared spectroscopy, gas chromatography with mass spectrometer, one-dimensional and two-dimensional nuclear magnetic resonance. The results indicated that the lyophilized GP1A was a homogeneous polysaccharide with a low molecular weight of 1.03 kDa. The dominating monosaccharides of GP1A were D-glucose, D-galactose, D-mannose, D-xylose and D-arabinose. The structure analysis indicated the main chain residues sequence of GP1A was α-D-Glcp-(6→3)-α-D-Galp-(1→1)-α-D-Glcp-(3→4)-β-D-Manp-(2→2)-β-D-Arap with branch chains of α-D-Glcp substituted at α-D-Galp and β-D-Xylp substituted at β-D-Manp.

Źródło:

Polish Journal of Food and Nutrition Sciences; 2023, 73, 1; 70-79
1230-0322
2083-6007

Pojawia się w:

Polish Journal of Food and Nutrition Sciences

Dostawca treści:

Biblioteka Nauki

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