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Tytuł:
ENDOGENOUS INSTITUTIONS AND ECONOMIC GROWTH: EVIDENCE FROM CHINA
Instytucje endogeniczne a wzrost gospodarczy na przykładzie Chin
Autorzy:
Li, Zhao
Chu, Yujing
Powiązania:
https://bibliotekanauki.pl/articles/947423.pdf
Data publikacji:
2020
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
economic institutions
ownership discrimination
capital allocation
economic growth
instytucje gospodarcze
dyskryminacja własności
alokacja kapitału
wzrost gospodarczy
Opis:
W artykule zbadano wpływ instytucji gospodarczych na akumulację kapitału w sektorze prywatnym przez sektor finansowy, a także cele działalności gospodarczej firm o zróżnicowanej strukturze własności w ramach socjalistycznej gospodarki rynkowej na przykładzie Chin w odniesieniu do neoklasycznej metody wzrostu gospodarczego. Autor stwierdził, że instytucje gospodarcze były głównym czynnikiem wpływającym na efektywność alokacji kapitału pomiędzy sektorem prywatnym a państwowym. Badania sugerują, że prywatne firmy starają się zatrudniać specjalistyczną kadrę w celu ulepszenia instytucji gospodarczych, aby zastąpić kapitał polityczny. Biorąc pod uwagę, że strategia reformy chińskich instytucji gospodarczych miała skalę ogólnokrajową po przeprowadzonym regionalnym projekcie pilotażowym, autor stwierdza, że reforma instytucji gospodarczych w regionach miała istotny wpływ na wzrost gospodarczy.
Źródło:
Financial Sciences. Nauki o Finansach; 2020, 25, 1; 54-77
2080-5993
2449-9811
Pojawia się w:
Financial Sciences. Nauki o Finansach
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic interactions stability analysis of hybrid renewable energy system with SSSC
Autorzy:
He, Ping
Qi, Pan
Ji, Yuqi
Li, Zhao
Powiązania:
https://bibliotekanauki.pl/articles/1841302.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
damping characteristics
dynamic interaction analysis
eigenvalue analysis
hybrid renewable energy system
SSSC
charakterystyka tłumienia
dynamiczna analiza interakcji
analiza wartości własnej
hybrydowy system energii odnawialnej
Opis:
The static series synchronous compensator (SSSC) has demonstrated its capability in providing voltage support and improving power system stability. The objective of this paper is to analyze the dynamic interaction stability mechanism of a hybrid renewable energy system connected with doubly-fed induction generators (DFIGs) and solid oxide fuel cell (SOFC) energy with the SSSC. For this purpose, a linearized mathematical model of this modified hybrid single-machine infinite-bus (SMIB) power system is developed to analyze the physical mechanism of the SSSC in suppressing oscillations and the influence on the dynamic stability characteristics of synchronization. Typical impacting factors such as the series compensation level, the SOFC penetration and tie-line power are considered in the SMIB and two-area systems. The impact of dynamic interactions on enhancing damping characteristics and improving transient performance of the studied systems is demonstrated using eigenvalue analysis and dynamic time-domain simulations, which validates the validity of the proposed physical mechanism simultaneously.
Źródło:
Archives of Electrical Engineering; 2021, 70, 2; 445-462
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of damping characteristics and index evaluation of a wind-PV-thermal-bundled power transmission system by combining PSS and SSSC
Autorzy:
He, Ping
Wu, Xinxin
Li, Congshan
Zheng, Mingming
Li, Zhao
Powiązania:
https://bibliotekanauki.pl/articles/140453.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
damping characteristics
eigenvalue analysis
power system stabilizer
wind-PV-thermal-bundled power system
Opis:
The grid integration of large-scale wind and solar energy affects the power flow of wind-PV-thermal-bundled power transmission systems and may introduce an unpredicted threat to the power system’s small signal stability. Meanwhile, a power system stabilizer (PSS) and static synchronous series compensator (SSSC) play an important role in improving the static and dynamic stability of the system. Based on this scenario and in view of the actual engineering requirements, the framework of wind-PV-thermal-bundled power transmitted by an AC/DC system with the PSS and SSSC is established considering the fluctuation of wind and photovoltaic power output and the characteristics of the PSS and SSSC. Afterwards, the situation model is constructed in the IEEE 2-area 4-unit system, and the influence of the PSS and SSSC on the system stability under different operating conditions is analyzed in detail through eigenvalue analysis and time-domain simulation. Finally, an index named the gain rate is defined to describe the improvement of the stability limitations of various wind-PV-thermal operating conditions with the PSS and SSSC. The results indicate (K) that the damping characteristics, dynamic stability and stability limitations for various wind-PV-thermal operating conditions of the wind-PV-thermal-bundled power transmission system can be significantly improved by the interaction of the PSS and SSSC.
Źródło:
Archives of Electrical Engineering; 2020, 69, 3; 705-721
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromechanical transient modeling of energy storage based on virtual synchronous machine technology
Autorzy:
Cui, Juntao
Li, Zhao
He, Ping
Gong, Zhijie
Dong, Jie
Powiązania:
https://bibliotekanauki.pl/articles/2135738.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
battery energy storage system
electromechanical transient model
virtual synchronous machine
Opis:
This paper proposes an electromechanical transient method to build a battery energy storage system-based virtual synchronous generator model, suitable for a large-scale grid. This model consists of virtual synchronous generator control, system limitation and the model interface. The equations of a second-order synchronous machine, the characteristics of charging/discharging power, state of charge, operating efficiency, dead band and inverter limits are also considered. By equipping the energy storage converter into an approximate synchronous voltage source with an excitation system and speed regulation system, the necessary inertia and damping characteristics are provided for the renewable energy power system with low inertia and weak damping. Based on the node current injection method by the power system analysis software package (PSASP), the control model is built to study the influence of different energy storage systems. A study on the impact of renewable energy unit fluctuation on frequency and the active power of the IEEE 4-machine 2-area system is selected for simulation verification. Through reasonable control and flexible allocation of energy storage plants, a stable and friendly frequency environment can be created for power systems with high-penetration renewable energy.
Źródło:
Archives of Electrical Engineering; 2022, 71, 3; 581--599
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the mechanism of a mixed collector onto magnesite surface to improve the flotation separation of magnesite from hornblende
Autorzy:
Wang, Enlei
Li, Xiaoan
Dai, Shujuan
Li, Zhao
Zhao, Tonglin
Song, Baoxu
Han, Baisui
Powiązania:
https://bibliotekanauki.pl/articles/1445774.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
magnesite
hornblende
mixed collector
flotation separation
Opis:
Low-grade magnesite is not effectively used mainly due to high silicon content, especially the separation of magnesite and hornblende. In this research, a novel mixture of sodium oleate and dodecyl phosphate collector was used to increase the flotation difference between magnesite and hornblende. Artificially mixed mineral concentrates grade 47.10% (MgO content) concentrate recovery of 84.45% was obtained by micro flotation test, the results showed that the mixed collector of sodium oleate and dodecyl phosphate played a better selective promotion role in the flotation of magnesite. The interaction mechanism of this mixed collector with hornblende and magnesite surfaces was investigated using Fourier transform infrared spectroscopy (FTIR), zeta potential, and X-ray photoelectron spectroscopy (XPS), which showed that the mixed collector in terms of magnesium selection was mainly adsorbed on these magnesium sites of magnesite, and the surface of magnesite thus became hydrophobic, allowing magnesite to float and separate from hornblende.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 125-138
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nature Cellulose Fibre Extracted from Different Cotton Stalk Sections by Degumming
Naturalne włókna celulozowe ekstrahowane z różnych części łodyg bawełny za pomocą odgumowywania
Autorzy:
Li, L.
Zhao, L.
Powiązania:
https://bibliotekanauki.pl/articles/233460.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
fibre extraction
cotton stalk
residue gum content
morphology
ekstrakcja włókna
bawełniana łodyga
odgumowanie
włókna łykowe
morfologia
Opis:
Bast fibres are important because they have biodegradable and eco-friendly characteristics. In this paper, natural cellulose fibre extracted from cotton stalk by degumming was investigated. On the basis on the chemical propertiess of cotton stalk bark, a cotton stalk was divided into three sections before fibres were extracted. Through an orthogonal experiment, the extracting conditions of fibres from different sections were obtained. The flexibility and linear density of the fibres extracted were then tested, and the morphology of the fibres was observed by SEM. It was shown that the flexibility and fineness of fibres from the different sections were various. The singular unit fibrel morphology of fibres from different sections had a visible difference.
Włókna łykowe odgrywają istotną rolę ponieważ są biodegradowalne i przyjazne środowisku. Badano naturalne celulozowe włókna ekstrahowane z łodyg bawełny poprzez odgumowywanie. Na podstawie właściwości chemicznych łodygę bawełny dzielono na trzy części przed przeprowadzeniem ekstrakcji. Doświadczalnie określono warunki ekstrakcji dla poszczególnych wyodrębnionych sekcji. Badano elastyczność i masę liniową, oraz za pomocą SEM morfologię. Stwierdzono, że zarówno elastyczność jak i masa liniowa włókien jest różna dla różnych sekcji łodygi. Morfologia jednostkowych włókien wyekstrahowanych różniła się widocznie dla wszystkich trzech części łodygi.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 6 (114); 37-40
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation influenced by the rheological properties of diaspore-pyrite mixed pulp
Autorzy:
Zhao, Yongqing
Li, Xianhai
Powiązania:
https://bibliotekanauki.pl/articles/27323666.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bauxite
diaspore
pyrite
flotation
rheological property
viscosity
Opis:
The effects of pyrite and diaspore with different particle sizes on the rheological properties of pulp with butyl xanthate added as a collector were studied, and the mechanism for rheological pyrite separation from diaspore by flotation was probed. The apparent viscosity of the diaspore pulp with different particle sizes was higher than that of pyrite, especially for -30 μm diaspore. Microfine diaspore was an important component affecting the apparent viscosity and yield stress of the diaspore-pyrite mixed pulp, and the pulp became a non-Newtonian fluid when the mass fraction of fine-grained diaspore in the mixed pulp was high. In this study, sodium hexametaphosphate (SHMP) was used to control the rheology of the mixed pulp and improve the pyrite flotation, and the S (sulfur) recovery rate first increased and then decreased with increasing SHMP concentration. The apparent viscosity of the pulp decreased by 3.01% and the S recovery rate increased by 34.83% when the amount of added SHMP was 0.05 mg/kg. The apparent viscosity with 0.50 mg/kg SHMP was 21.76% lower than that seen with the addition of 0.05 mg/kg SHMP, but the S recovery rate was also reduced by 14.94%. Further research showed that the increased SHMP concentration led to increases in the electronegativities of the particle surface and the repulsive force between particles, which prevented agglomeration of the particles, reduced the apparent viscosity and yield stress of the mixed pulp, promoted collisions between the pyrite particles and the bubbles, and reduced the resistance of the air bubbles to flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174305
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Influencing Factors of the Acoustic Performance of the Muffler Considering Acoustic-structural Coupling
Autorzy:
Zhao, Bo
Li, He
Powiązania:
https://bibliotekanauki.pl/articles/31339942.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
acoustic performance
muffler
acoustic-structural coupling
transmission loss
mode
optimisation
Opis:
In the calculation of the acoustic performance of mufflers, the walls of mufflers are usually treated rigidly without considering the acoustic-structural coupling, but the results so calculated differ significantly from the actual situation. Based on the basic equations, the article derives the finite element equations of the muffler system while considering the acoustic-structural coupling effect and theoretically analyses the connection between the acoustic-structural coupling system and the structural and acoustic modes. The structural and acoustic modes of the muffler are calculated and the reasons for the mutation of the transmission loss curve of the muffler when the acoustic-structural coupling is considered are analysed. The results show that the acoustic-structural coupling is the result of the interaction between the structure and the air inside the expansion chamber under acoustic excitation, which manifests mutations in the sound pressure inside the muffler in some frequency bands. Then, using a single-chamber muffler as an example, the transmission loss is used to characterise the performance of the muffler. The effects of different factors such as shell thickness, structure, porous media material lining, and restraint method on the acoustic-structural coupling effect of the muffler are analysed, and the structure of a double-chamber muffler is successfully optimised according to the conclusions.
Źródło:
Archives of Acoustics; 2022, 47, 4; 479-490
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal conductivity of a Brown Earth soil as affected by biochars derived at different temperatures: Experiment and prediction with the Campbell model
Autorzy:
Zhao, B.
Li, L.
Zhao, Y.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/2082959.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
biochar
bulk density
thermal conductivity
Brown Earth soil
Campbell model
Opis:
Thermal conductivity is a significant heat transfer property of soil. However, the influence of biochar on this property is not well known. In this research, the influence of corn straw biochars prepared at 300, 500 and 700oC on the thermal conductivity of a Brown Earth (Hapli-Udic Cambisol, FAO) soil and its prediction using a Campbell model was examined. The outcomes revealed that the bulk densities of the soil markedly decreased with increases in the biochar amendment rates of 1, 3, and 5% in linear patterns. The reduction in bulk density was mainly attributed to an increase in soil porosity and organic carbon content. With increasing volumetric water contents (10, 20, 30 and 40%), the thermal conductivity of the soils significantly increased, whereas those of soils with biochar amendment were obviously less than that of the CK and the differences increased with the biochar application rates. The pyrolysis temperature of biochar exhibited a negligible effect on the bulk density and thermal conductivity of soils at large. Combining the linear reduction of bulk density with the biochar amendment rate into the Campbell model, well-fitting results for the variation inthermal conductivity versus volumetric water content were obtained and accurate values could be predicted.
Źródło:
International Agrophysics; 2020, 34, 4; 433-439
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery of Fe and V via selective reduction–magnetic separation of vanadium-titanium magnetite concentrate
Autorzy:
Liu, Liwei
Li, Guofeng
Zhao, Libing
Li, Jinpeng
Li, Yanfeng
Powiązania:
https://bibliotekanauki.pl/articles/2146847.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium-titanium magnetite concentrate
selective reduction
magnetic separation
Fe separation
V separation
Opis:
With the aim of separating Fe and V, a vanadium-titanium magnetite concentrate was selectively reduced, followed by magnetic separation. The processes accompanying reduction of the vanadium-titanium magnetite concentrate were investigated using thermodynamic simulation, experiments, scanning electron microscopy, and electron probe microanalysis. Appropriate reduction conditions and controlling the amount of CaCO3 promoted the reduction of Fe-containing minerals to metallic Fe. V was released from magnetite, ilmenite, and titanomagnetite, and was inhibited to reduce to metallic V, leading to V enrichment in the non-magnetic products in the form of oxides. Moreover, the Fe particles wrapped the slag phase when the amount of CaCO3 exceeded 8%, which is unfavourable for the magnetic separation of Fe and V. Magnetic products with an Fe content of 87.19%, Fe recovery of 82.62%, V content of 0.09% and non-magnetic products with a V content of 1.00% and a V recovery of 85.49% were obtained when the vanadium-titanium magnetite concentrate was reduced for 100 min at 1623 K with a C/O molar ratio of 2.5 and 8% CaCO3, followed by separating at a magnetic field strength of 85 mT.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 1; 50--62
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Cultural Aspects of 20th Century Chinese Xiangjin Brocade
Autorzy:
Wenji, Zhao
Rongrong, Cui
Li, Niu
Powiązania:
https://bibliotekanauki.pl/articles/2172002.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
Xiangjin brocade
design feature
oriental art feature
weaving technique
pattern schema
Opis:
As one of the representative silk-woven artworks of the 20th century in China, Chinese Xiangjin brocade, well-known as "the flower of Oriental art", draws on the essence of Sichuan brocade, Yun brocade, Song brocade, so as to form its own unique artistic style. It also takes the lead in the innovation of traditional brocade in key processes such as craftsmanship, design and jacquard, whose drawing technique is the exact core skill making it intangible cultural heritage. So far, there have been few studies on crafts and textile design in China before the 20th century or even after the reform and opening up, and rather fewer studies on the structure of Xiangjin brocade in the 20th century. This paper attempts to record and classify 1008 pieces of Xiangjin brocade in the Suzhou Silk Archive, China, as well as to find out their design features, oriental flavour, and unique weaving techniques. In addition, the cultural connotation of Xiangjin brocade as the painting medium was also put forward by analysing those brocades’ historical texts, images, and style.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 3 (151); 116--129
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reactive power convex optimization of active distribution network based on Improved GreyWolf Optimizer
Autorzy:
Li, Yuancheng
Yang, Rongyan
Zhao, Xiaoyu
Powiązania:
https://bibliotekanauki.pl/articles/140678.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active distribution network (ADN)
Improved Grey Wolf Optimizer (IGWO)
reactive power optimization
second-order cone relaxed convex model
Opis:
The smart grid concept is predicated upon the pervasive With the construction and development of distribution automation, distributed power supply needs to be comprehensively considered in reactive power optimization as a supplement to reactive power. The traditional reactive power optimization of a distribution network cannot meet the requirements of an active distribution network (ADN), so the Improved Grey Wolf Optimizer (IGWO) is proposed to solve the reactive power optimization problem of the ADN, which can improve the convergence speed of the conventional GWO by changing the level of exploration and development. In addition, a weighted distance strategy is employed in the proposed IGWO to overcome the shortcomings of the conventional GWO. Aiming at the problem that reactive power optimization of an ADN is non-linear and non-convex optimization, a convex model of reactive power optimization of the ADN is proposed, and tested on IEEE33 nodes and IEEE69 nodes, which verifies the effectiveness of the proposed model. Finally, the experimental results verify that the proposed IGWO runs faster and converges more accurately than the GWO.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 117-131
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical Studies on Marine Accidents Happened on the Bohai Sea
Autorzy:
Wu, Z.
Zhao, J.
Li, G.
Powiązania:
https://bibliotekanauki.pl/articles/116959.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Marine Accidents
Ship Accidents
Marine Traffic Accidents
Chinese Navigable Waterways
Weather Condition
Decision Making Process
Human Factor
Statistical Study
Opis:
a statistical study is carried out on the basis of information of marine traffic accidents occurred from 1996 to 2005 on the Bohai Sea. The time distribution and geographic distribution of the marine traffic accidents, as well as the relationships between the accidents and weather condition, type of accidents area, accident category, size of ships are analyzed, which provide references for adopting safety decision-making and take relative precautionary measures to avoid and decrease occurrence of accidents.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2008, 2, 2; 183-186
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the states of polarization of random electromagnetic beams in atmospheric turbulence
Autorzy:
Li, J.
Zhao, K.
Lai, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174110.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
non-Kolmogorov atmospheric turbulence
random electromagnetic beams
degree of polarization
orientation angle
degree of ellipticity
Opis:
Taking the random electromagnetic cosh-Gaussian beam as a typical example of random electromagnetic beams, the analytical expressions for the cross-spectral density matrix element of random electromagnetic cosh-Gaussian beams propagating through non-Kolmogorov atmospheric turbulence are derived, and used to study the changes in the states of polarization (degree of polarization, orientation angle and degree of ellipticity) of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence. It is shown that the states of polarization of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence are different from those in free space. The degree of polarization decreases, and the orientation angle and degree of ellipticity increase with increasing structure constant. The on-axis degree of polarization and the degree of ellipticity appear to have an oscillatory behavior and the orientation angle has a rapid transition for the larger cosh-part parameter of random electromagnetic cosh-Gaussian beams in atmospheric turbulence.
Źródło:
Optica Applicata; 2017, 47, 1; 51-62
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Yarn Fineness and Stitch Length of Polyester Knitted Fabric on the Dielectric Constant
Wpływ grubości przędzy i długości oczka dzianiny poliestrowej na stałą dielektryczną
Autorzy:
Liu, Yuanjun
Li, Wenyue
Zhao, Xiaoming
Powiązania:
https://bibliotekanauki.pl/articles/233148.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
polyester knitted fabric
yarn fineness
stitch length
dielectric constant
absorbing properties
dzianina poliestrowa
grubość przędzy
długość ściegu
stała dielektryczna
właściwości pochłaniające
Opis:
The influence of the yarn fineness and stitch length of polyester knitted fabrics on the dielectric constant was investigated by the single factor test method. As a result of the investigation, polyester knitted fabric parameters were chosen so as to obtain a polyester knitted fabric with the maximum real part and imaginary part of the dielectric constant. The results show that when the yarn fineness is 59 tex and the mark of the stitch length is 75, the polyester knitted fabric displayed the maximum real part and imaginary part of the dielectric constant. Finally, the polyester knitted fabric with these parameters had good microwave absorbing properties.
W pracy, metodą testu jednoczynnikowego, badano wpływ grubości przędzy i długości oczka dzianin poliestrowych na stałą dielektryczną. W wyniku badań dobrano parametry dzianiny poliestrowej, tak aby uzyskać dzianinę o maksymalnej stałej dielektrycznej. Wyniki pokazały, że przy grubości przędzy wynoszącej 59 tex i długości oczka 75, dzianina poliestrowa charakteryzowała się najwyższą stałą dielektryczną i miała dobre właściwości pochłaniania mikrofal.
Źródło:
Fibres & Textiles in Eastern Europe; 2019, 6 (138); 63-66
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analytic Investigation of "Hot-Spot" Formation in Compressible Energetic Materials
Autorzy:
Li, X.
Zhao, F.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/358425.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
analytic model
bulk compressibility
pore collapse
"hot-spot" formation
Opis:
In this paper, the formation of the shock-induced “hot-spot” in compressible energetic materials has been analyzed. By applying the compressible elastic-viscoplastic material model to a hollow sphere, and solving the governing equations with the initial and boundary conditions, this paper proposes an analytic pore collapse model that is able to simulate the viscoplastic deformation which determines the formation of a “hot-spot”. In this new model there are three mechanisms, of which instantaneous deformation and the subsequent quasi-static incompressible deformation dominate “hot-spot” formation, while quasi-static compressible deformation is of little effect. In comparison with the incompressible solution, this model demonstrates that the bulk compressibility has a great influence on “hot-spot” formation, as the degree of the “hot-spot” reaction is a positive quasi-linear function of Poisson’s ratio ν. An error in Kim’s original pore collapse model has also been discussed.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 806-820
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability modeling of fault tolerant control systems
Autorzy:
Li, H.
Zhao, Q.
Yang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/929822.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie tolerujące uszkodzenia
ocena niezawodności
procesy semimarkowskie
fault tolerant control
reliability evaluation
semi-Markov processes
Opis:
This paper proposes a novel approach to reliability evaluation for active Fault Tolerant Control Systems (FTCSs). By introducing a reliability index based on the control performance and hard deadline, a semi-Markov process model is proposed to describe system operation for reliability evaluation. The degraded performance of FTCSs in the presence of imperfect Fault Detection and Isolation (FDI) is reflected by semi-Markov states. The semi-Markov kernel, the key parameter of the process, is determined by four probabilistic parameters based on the Markovian model of FTCSs. Computed from the transition probabilities of the semi-Markov process, the reliability index incorporates control objectives, hard deadline, and the effects of imperfect FDI, a suitable quantitative measure of the overall performance.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 4; 491-504
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pyrite oxidation inhibition by hydrophobic films for acid mine drainage control at the source
Autorzy:
Wang, Shuncai
Zhao, Yue
Li, Shuang
Powiązania:
https://bibliotekanauki.pl/articles/110200.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydrophobic film
pyrite
suppression
linoleic acid
acid mine drainage
Opis:
Acid mine drainage (AMD), which is also known as acid rock drainage (ARD), can cause serious environmental pollution, especially for surrounding aquatic and terrestrial ecosystems due toits low pH, high metal and sulfate concentration. Acid mine drainage is an urgent environmental problem for the worldwide ore mining industry. In this paper, we demonstrated that hydrophobic films can inhibit the oxidation of pyrite-bearing tailings to achieve the control of at-source AMD. The results of chemical leaching testing showed that the hydrophobic films formed by linoleic acid can suppress the oxidation of pyrite-bearing tailings and reduce the AMD production. In addition, the presence of hydrophobic films of linoleic acid on the surface of pyrite-bearing tailings was confirmed by the results from Fourier transform infrared (FTIR) analyses and scanning electron microscopy with energy dispersive spectrometry (SEM / EDS).
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 5; 1132-1140
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations and Comparisons of Active Q-Switching Laser Performances of Composite and Conventional Nd:$YVO_4$ Crystals with Electro-Optic Modulator
Autorzy:
Li, Shixia
Li, Yufei
Zhao, Shengzhi
Li, Guiqiu
Wang, Xiaomei
Yang, Kejian
Li, Tao
Li, Dechun
Powiązania:
https://bibliotekanauki.pl/articles/1398735.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Xi
42.60.Gd
Opis:
Actively Q-switched laser performances of composite and conventional Nd:$YVO_4$ crystals were investigated and compared with different Nd-doped concentrations of laser media and different repetition rates of electro-optic modulator. Both continuous-wave and actively Q-switched operations were realized experimentally. At an incident pump power of 7.69 W, the shortest pulse duration of 6.5 ns was obtained by the composite Nd(0.1 at.%):$YVO_4$/Nd(0.3 at.%):$YVO_4$/Nd(0.8 at.%):$YVO_4$ crystal at the repetition rate f=2 kHz. However, the composite Nd(0.1 at.%):$YVO_4$/Nd(0.5 at.%):$YVO_4$/Nd(1.0 at.%):$YVO_4$ laser achieved the maximum average output power of 687 mW at f=10 kHz and the largest single pulse energy of 144 μ J at f=2 kHz. Power saturation of the conventional Nd:$YVO_4$ crystal was shown during experiment, while no power saturation was observed on the composite Nd:$YVO_4$crystals, showing good thermo-mechanical performances.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 711-714
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calibration of backward-in-time model using drifting buoys in the East China Sea
Autorzy:
Yu, F.
Li, J.
Zhao, Y.
Li, Q.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/47533.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
crude oil
marine environment
marine pollution
oil spill
China Sea
random walk
wind field
calibration
Opis:
In the process of oil exploitation and transportation, large amounts of crude oil are often spilled, resulting in serious pollution of the marine environment. Forecasting oil spill reverse trajectories to determine the exact oil spill sources is crucial for taking proactive and effective emergency measures. In this study, the backward-in-time model (BTM) is proposed for identifying sources of oil spills in the East China Sea. The wind, current and random walk are three major factors in the simulation of oil spill sources. The wind drag coefficient varies along with the uncertainty of the wind field, and the random walk is sensitive to various traits of different regions, these factors are taken as constants in most of the state-of-the-art studies. In this paper, a self-adaptive modification mechanism for drift factors is proposed, which depends on a data set derived from the drifter buoys deployed over the East China Sea shelf. It can be well adapted to the regional characteristics of different sea areas. The correlation factor between predicted positions and actual locations of the drifters is used to estimate optimal coefficients of the BTM. A comparison between the BTM and the traditional method is also made in this study. The results presented in this paper indicate that our method can be used to predict the actual specific spillage locations.
Źródło:
Oceanologia; 2017, 59, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal performances and optical property of poly(L-lactic acid) under the influence of N,N’-dodecanedioic bis(3-phenylpropionic acid) dihydrazide as a crystallization promoter
Wpływ dihydrazydu kwasu bis(3-fenylopropiono) N,N’-dodekanodiowego jako promotora krystalizacji na właściwości termiczne i optyczne poli(kwasu L-mlekowego)
Autorzy:
Yang, Xiao-Yu
Zhao, Li-Sha
Cai, Yan-Hua
Zhao, Jie
Wang, Lin
Ma, Xiao-Li
Powiązania:
https://bibliotekanauki.pl/articles/945767.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
poly(L-lactide)
dodecanedioic acid dihydrazide
nucleating agent
crystallization
poli(L-laktyd)
dihydrazyd kwasu dodekanodiowego
środek zarodkujący
krystalizacja
Opis:
Poly(L-lactic acid) (PLLA) as an important biodegradable polymer suffers from slow crystallization rate and poor heat resistance. An organic compound N,N’-dodecanedioic bis(3-phenylpropionic acid) dihydrazide (BHADD) was synthesized to evaluate its general influences on the physical properties of PLLA. The melt-crystallization process indicated that BHADD could serve as a heterogeneous nucleating agent for improving the crystallization of PLLA, and PLLA/1%BHADD exhibited the sharpest melt-crystallization peak located at the highest temperature, as well as an increase of cooling rate weakened the crystallization ability of BHADD-nucleated PLLA. And the final melting temperature also displayed the significant effect on the crystallization process of PLLA. For the cold-crystallization process, both BHADD concentration and heating rate affected the cold-crystallization behavior of PLLA/BHADD, the increasing of BHADD concentration caused the cold-crystallization peak to shift to the lower temperature; in contrast, a higher heating rate during heating leaded to the peak’s shift toward the higher temperature because of the thermal inertia. The melting behavior of PLLA/BHADD depended on the crystallization temperatures and heating rates, and the double melting peaks were attributed to the melting-recrystallization. Thermal decomposition experiment showed all PLLA/BHADD samples as the pure PLLA only exhibited one thermal decomposition stage, but PLLA/BHADD had a lower thermal stability than the pure PLLA. Additionally, the addition of BHADD seriously decreased the light transmittance of PLLA.
Poli(kwas L-mlekowy) (PLLA) to ważny biodegradowalny polimer charakteryzujący się małą szybkością krystalizacji i słabą odpornością na ciepło. Dihydrazyd kwasu bis(3-fenylopropiono) N,N'-dodekanodiowego (BHADD) zsyntetyzowano w celu oceny jego wpływu na właściwości fizyczne PLLA. Przebieg procesu krystalizacji ze stopu świadczy o tym, że BHADD może służyć jako heterogeniczny środek zarodkujący zwiększający szybkość krystalizacji PLLA. Mieszanina PLLA/1% mas. BHADD wykazywała najostrzejszy pik krystalizacji ze stopu zlokalizowany w zakresie najwyższej temperatury, a jednocześnie większą szybkość chłodzenia osłabiającą zdolność krystalizacji PLLA zarodkowanej BHADD. Również końcowa temperatura topnienia w istotnym stopniu wpływała na proces krystalizacji PLLA. W procesie krystalizacji na zimno zarówno stężenie BHADD, jak i szybkość ogrzewania oddziaływały na zachowanie PLLA/BHADD podczas krystalizacji, zwiększenie stężenia BHADD powodowało przesunięcie piku krystalizacji na zimno w kierunku niższej temperatury, natomiast większa szybkość ogrzewania prowadziła do, spowodowanego bezwładnością cieplną, przesunięcia piku krystalizacji na zimno w kierunku wyższej temperatury. Zachowanie PLLA/BHADD podczas topnienia zależało od temperatury krystalizacji i szybkości ogrzewania, a drugi pik topnienia przypisano procesowi rekrystalizacji. Badany przebieg rozkładu termicznego świadczy, że wszystkie próbki PLLA/BHADD, tak jak czysty PLLA, wykazywały tylko jeden etap rozkładu termicznego, mieszanina PLLA/BHADD charakteryzowała się jednak mniejszą stabilnością termiczną niż czysty PLLA. Dodatek BHADD w znacznym stopniu zmniejszył przepuszczalność światła PLLA.
Źródło:
Polimery; 2020, 65, 7-8; 523-532
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phylogenetic Analyses on the Tintinnid Ciliates (Protozoa, Ciliophora) Based on Multigene Sequence Data
Autorzy:
Zhao, Yan
Gao, Feng
Li, Jiqiu
Yi, Zhenzhen
Powiązania:
https://bibliotekanauki.pl/articles/763453.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Phylogeny, Ciliophora, choreotrichs, Tintinnida, SSU rDNA, ITS1-5.8S-ITS2 region, ITS2 secondary structure
Opis:
In order to better understand phylogenetic relationships among tintinnid ciliated protozoa, we sequenced and analyzed the SSU rDNA and ITS1-5.8S-ITS2 regions of 10 species belonging to five genera in the order Tintinnida. The secondary structures of the ITS2 region were compared among 8 closely related genera, revealing two stable helices of the palm. In addition, we identified a bulge absence in position II of the ITS2 putative secondary structures of species in basal positions in phylogenetic trees, suggesting the absence bulge might be an ancestral character in the order Tintinnida. Phylogenetic analyses based on SSU rDNA and ITS1-5.8S-ITS2 regions sequence show 1) divergences within the family Tintinnidae are higher than that among other four families (Codonellidae, Ptychocylididae, Metacylididae and Codonellopsidae), suggesting the subdivision of the this family; 2) the family Ptychocylididae is polyphyletic; 3) the subdivision of Tintinnopsis are suggested, because the Tintinnopsis spp. scatter into different clades; 4) species with agglutinated loricae are not clearly separated from that with hyaline ones.
Źródło:
Acta Protozoologica; 2012, 51, 4
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Renewable warranty policy for multiple-failure-mode product considering different maintenance options
Polityka odnawiania gwarancji dla produktówo mnogich przyczynach uszkodzeń uwzględniająca różne opcje obsługi
Autorzy:
Li, X.
Jia, Y.
Wang, P.
Zhao, J.
Powiązania:
https://bibliotekanauki.pl/articles/301949.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
multiple failure modes
renewing warranty
preventive maintenance
warranty cost
product availability
upgrading maintenance
mnogie przyczyny uszkodzeń
odnowienie gwarancji
obsługa profilaktyczna
koszty gwarancji
gotowość produktu
konserwacja modernizacyjna
Opis:
Along with the advancement of manufacturing techniques, the quality of the spares for product is likely to be improved during the warranty period. There can be two types of spares, i.e. low-quality spares and high-quality spares for replacement maintenance. And the manufacturers (customers) may have to decide whether or not to provide (buy) the warranty considering upgrading maintenance. This paper presents a renewing warranty policy considering three maintenance options for products with multiple failure modes. The cost and availability models of these maintenance options are proposed. Of these options, upgrading maintenance is taken into account with the assumption that the warrantied item will be upgraded one time during the warranty cycle. After upgrading maintenance, the high-quality spares are used to replace the failed item. By minimizing the ratio between cost and availability of the product, the optimal upgrading opportunity is obtained. In the numerical example, the results of these options are presented. Monte Carlo simulation results are compared with the analytical results to demonstrate the correctness and efficiency of the proposed models considering upgrading maintenance. The renewing warranty policy considering upgrading maintenance policy is compared with the one without considering upgrading maintenance. The results show that the former is better than the latter in some cases. The sensitivity of the cost model and availability model to different parameters is analyzed at last.
Wraz z postępem techniki produkcji, wzrasta prawdopodobieństwo, że jakość części zamiennych do produktu ulegnie poprawie w przeciągu okresu gwarancyjnego. Istnieją dwa rodzaje części zamiennych: części zamienne niskiej i wysokiej jakości. Producenci (klienci) mogą być zmuszeni podjąć decyzję czy objąć produkt gwarancją (wykupić gwarancję) zapewniającą konserwację modernizacyjną. W artykule przedstawiono politykę odnawiania gwarancji z uwzględnieniem trzech różnych opcji obsługi produktów narażonych na mnogie przyczyny uszkodzeń. Zaproponowano modele kosztów i gotowości dla omawianych opcji obsługi. Spośród badanych opcji, do dalszej analizy wybrano konserwację modernizacyjną zakładającą, że element podlegający gwarancji zostanie poddany jednokrotnej modernizacji podczas cyklu gwarancyjnego. Po wykonaniu konserwacji modernizacyjnej, uszkodzony element zastępuje się częściami zamiennymi wysokiej jakości. Minimalizując stosunek kosztów do gotowości produktu, uzyskuje się optymalną możliwość modernizacji Przykład numeryczny przedstawia wyniki uzyskane dla omawianych opcji. Wyniki symulacji Monte Carlo porównano z wynikami analitycznymi w celu wykazania prawidłowości i efektywności proponowanych modeli uwzględniających konserwację modernizacyjną. Politykę odnawiania gwarancji uwzględniającą konserwację modernizacyjną porównano z polityką, która takiej konserwacji nie uwzględnia. Wyniki pokazują, że pierwsza z tych opcji jest w niektórych przypadkach korzystniejsza od drugiej. Badania wieńczy analiza czułości modelu kosztów i modelu gotowości na różne parametry.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 4; 551-560
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and optimisation of vacuum collection system for cruise ship kitchen garbage
Autorzy:
Du, Jun
Li, Ruonan
Wu, Xin
Zhao, Hang
Powiązania:
https://bibliotekanauki.pl/articles/259756.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
kitchen waste vacuum collection
System modeling
Sorting algorithm
Model experiment
Opis:
Pollution of the marine environment by ship garbage is an urgent problem to be solved at home and abroad. The ship kitchen garbage vacuum collection system is a new environmental protection scheme for garbage disposal. It has many advantages, such as using a pipeline instead of manual operation, creating high-level sanitary conditions, realising completely closed garbage collection and transportation, eliminating cross-pollution, saving space and so on. In this paper, the system is modelled, and the calculation of pipeline pressure loss, the vacuum degree of the vacuum tank and the energy consumption of the system are briefly introduced. In order to reduce the energy consumption, an algorithm for the emptying and discharging port is presented. In order to solve the problem of optimising relevant parameters, the vacuum transport mechanism of garbage is studied based on an optimisation model of the pipe network, and the experimental platform of a simulation device is set up. In engineering, this is of great significance to the design of cruise ship garbage collection and treatment systems and the development of supporting technology.
Źródło:
Polish Maritime Research; 2020, 1; 152-161
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The direct and indirect effect of fire on radial growth of Pinus koraiensis trees in a northern temperate forest of China
Autorzy:
Gao, Lushuang
Zhang, Chunyu
Zhao, Xiuhai
Zhang, Li
Powiązania:
https://bibliotekanauki.pl/articles/956863.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
burned trees
growth pattern
competition
climate
korean pine
Opis:
The long-term effects of fire on the radial growth of Korean pines (Pinus koraiensis) in Changbai Mountain is poorly understood. In order to quantify the impact of fire on the radial growth of Korean pines, we measured ring widths and developed two tree-ring chronologies from 21 burned Korean pine trees that were damaged by fire in 1857 as well as 30 control trees in the Changbai Mountain Nature Reserve, China. As expected, the growth rates of the burned trees were slower than those of the control trees in the first five years following the fire. However, beginning six years after the fire, the growth of the burned trees increased considerably, and this period of increased growth lasted 13 years, with moderate growth occurring throughout the 1866 to 1871 period. A difference in growth rates between burned and control tress was also observed for the 20 years since temperatures began markedly increasing in 1980. Burned trees tended to respond negatively to monthly minimum temperature, precipitation, and vapor pressure deficits (VPD), whereas the positive relationship between those factors and radial growth of control trees became stronger. In addition, the significantly negative effect of competition on radial growth was only observed among burned trees. These results demonstrated that the negative and direct effect of damage to physiological plant processes by fire only affected the years shortly after a fire occurred and then became obscured by its indirect effects, such as differential responses to climate and competition, which did persist for a long time. The indirect effect on radial growth over time could be explained by the variability in the relative strength of climatic responses and competition caused by fire.
Źródło:
Dendrobiology; 2017, 78; 111-123
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and theoretical research on large-diameter rock-socketed pile embedded depth
Autorzy:
Li, Yanfeng
Zhao, Jihe
Xiong, Ying
Wang, Qinghe
Powiązania:
https://bibliotekanauki.pl/articles/1852536.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
badanie obciążeniowe
obciążenie poziome
model elementów skończonych
przenoszenie obciążenia
nośność graniczna
głębokość
gniazdo skalne
pal fundamentowy
pal wielkośrednicowy
horizontal load
loading test
finite element model
load transfer
ultimate bearing capacity
rock socket
depth
foundation pile
large diameter pile
Opis:
A theoretical formula for large-diameter rock-socket depth is developed to support pail embedding in a large bridge pile foundation project. There is a horizontal additional stress concentration at the place where the soil around the rock-socketed pile meets the soil layer under the horizontal load. When the rock-socketed tip stress and bending moment of the pile are relatively small, the pile shows favourable embedment effect and the pile foundation can be considered safe. The function curve of soil resistance around the pile under the action of horizontal force was obtained by finite element analysis. The force characteristics reveal the depth of the largediameter rock-socketed pile under the horizontal load. As the rock-socketed pile rotates under the action of horizontal force, the rock mass resistance around the pile changes according to the cosine. The distribution of pileside soil resistance is proportional to the displacement and distributed according to the sine. A comprehensive correction coefficient of pile shaft resistance β is introduced to deduce the theoretical formula of the depth hr of the large-diameter rock-socketed pile embedded in the bedrock. It is verified through both experiments and numerical analysis.
Źródło:
Archives of Civil Engineering; 2021, 67, 2; 537-550
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nano-sized micelles formed by self-assembling of polylactide(ethylene glycol) block copolymers in aqueous solutions
Autorzy:
Yang, L.
Zhao, Z.
Wei, J.
Li, S.
Powiązania:
https://bibliotekanauki.pl/articles/284952.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
kopolimery
copolymers
Źródło:
Engineering of Biomaterials; 2007, 10, no. 63-64; 16-18
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation kinetics and separation selectivity of coal size fractions
Autorzy:
Li, Y.
Zhao, W.
Gui, X.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/110676.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal
flotation rate
combustible matter recovery
ash
particle size
Opis:
Flotation recovery and kinetics for three size fractions of coal were investigated. Flotation of combustible matter recovery was approximated with the first order kinetic equation while flotation of the ash forming minerals with the second order equation. Next, the equations for each size fraction were combined and a formula was obtained which was used for approximation of the experimental results using the so-called Fuerstenau upgrading curve, which relates the recovery of combustible matter recovery and recovery of ash forming minerals, both in concentrate. The Fuerstenau upgrading plot showed that the best selectivity was obtained for the middle size fraction of 0.25–0.075 mm, while the flotation selectivity of larger 0.5–0.25 mm and smaller –0.075 mm particles was diminished. This finding agrees with many other investigations.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 2; 387-395
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fillet effect on the bending crashworthiness of thin-walled square tubes
Autorzy:
Xie, Zhongyou
Zhao, Zhixian
Zhou, Xiuneng
Li, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/2086940.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
thin-walled square tubes
bending crashworthiness
fillet effect
three-point bending
finite element analysis
Opis:
Filleting four corners of square tubes is suggested to reduce the peak force and improve energy absorbing performance. Three-point bending tests are conducted to investigate fillet radius effects employing an ABAQUS explicit code. Three cases characterized by the ratio of width to thickness are considered. Fillet greatly reduces the maximum forces compared with square cross-sections, and the normalized maximum forces decrease with increasing wall thickness when the fillet radius is larger. Additionally, the fillet dramatically improves SEA (Specific Energy Absorption). The normalized CFE (Crash Load Efficiency) significantly exceeds that of the square ones, and the normalized CLEs are almost identical with the increasing fillet radius.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 103--111
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Collapse modes of concrete reinforced square bridge piers under vehicle collision
Autorzy:
Zhou, Xiuneng
Xie, Zhongyou
Zhao, Zhixian
Li, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/2086980.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
RC square pier
collapse mode
vehicle collision
numerical simulation
Opis:
In the field of engineering protection, there is a structural disaster named heavy vehicles impacting column structures. When a heavy truck collides with a reinforced concrete (RC) column at a high velocity, a large impact force generated makes perhaps the column fail and even collapse. Therefore, it is necessary to study the dynamic characteristics during such a disaster, which can provide some reference for structural design, optimization and protection. The RC column impacted by a vehicle could be simplified as a beam fixed at the bottom loaded by a concentrated force, whose deformation is controlled by shearing and bending. In the present work, the ultimate static forces corresponding to shearing and bending collapse are proposed based on theoretical analyses. The model validation is performed using the finite element approach and the theoretical analytical results are in good agreement with the finite element simulation results, which validates the present analytical model. Three cases are simulated by utilizing finite element code ABAQUS, which reveals that the approximate plateau collapse force keeps a long stage beyond the peak failure one. In addition, three collapse modes are observed based on the static force and deformation analysis, validating the present framework which can be used for routine pier design. The work can be extended to estimate collapse modes of building columns under a vehicle collision.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 375--384
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific emitter identification using geometric features of frequency drift curve
Autorzy:
Zhao, Y.
Wui, L.
Zhang, J.
Li, Y.
Powiązania:
https://bibliotekanauki.pl/articles/200575.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
specific emitter identification
geometric features
frequency drift
adaptive fractional spectrogram
support vector machine
emiter
cechy geometryczne
dryf częstotliwości
spektrogram
Opis:
Specific emitter identification (SEI) is a technique for recognizing different emitters of the same type which have the same modulation parameters. Using only the classic modulation parameters for recognition, one cannot distinguish different emitters of a same type. To solve the problem, new features urgently need to be developed for recognition. This paper focuses on the common phenomenon of frequency drift, defines geometric features of frequency drift curve and, finally, proposes a practical algorithm of specific emitter identification using the geometric features. The proposed algorithm consists of three processes: instantaneous frequency estimation based on the adaptive fractional spectrogram, feature extraction of frequency drift curve based on geometric methods for describing a curve and recognition process based on support vector machine. Simulation results show that the identification rate is generally more than 98% above –5 dB of signal to noise ratio (SNR), and real data experiment verifies the practical performance of the proposed algorithm.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 99-108
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-dimensional simulation of the fracture system distribution in formation rock based on fractal method
Trójwymiarowe symulacje rozkładu spękań w skałach z wykorzystaniem metody fraktali
Autorzy:
Li, W.
Zhao, H.
Liu, M.
Li, S.
Sun, W.
Wang, L.
Powiązania:
https://bibliotekanauki.pl/articles/219509.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
szczelinowanie hydrauliczne
wymiary fraktali
naturalne spękania
spękania powstałe wskutek szczelinowania
symulacje numeryczne
hydraulic fracturing
fractal dimension
natural fracture
fracturing fracture
numerical simulation
Opis:
During exploitation process of fractured reservoir, the complex distribution of natural fracture system may lead to a series of accidents, such as sand plug and multi fracture extension in hydraulic fracturing operation. Considering the difficulties of numerical analysis on formation rock mass fracture system distribution, three-dimensional geometry model of a single fracture formation is proposed in this paper, and fractal geometry method is introduced to build the three-dimensional fractal description model of formation fracture system distribution. On this basis, the effects of fractal parameters on natural fracture porosity, permeability and other properties are analyzed. The results show that: First, the number and propagation of natural fracture are controlled by the fractal dimension, the number of groups and the initial quantity. Second, the fractal dimension of natural fracture distribution has an obvious effect on natural fracture porosity and permeability. Third, porosity and permeability of natural fracture distribution both experience exponential growth as fractal dimension increases. Fourth, when the fractal dimension remains constant, the porosity and permeability of natural fractures both increase with the fracture scale.
W trakcie eksploatacji złoża zalęgającego w spękanych warstwach i pokładach złożony system naturalnych spękań prowadzić może do licznych incydentów, np. powstawania zatorów piaskowych lub nadmiernego rozszerzenia spękań w trakcie szczelinowania hydraulicznego. Z uwagi na trudności związane z analizą numeryczną rozkładu spękań skał macierzystych, w pracy zaproponowano trójwymiarowy model geometryczny pojedynczego pęknięcia z wykorzystaniem metod geometrii fraktalnej do opracowania trójwymiarowego modelu opisującego powstawanie układu spękań i ich rozkład. Na tej podstawie przeanalizowano wpływ parametrów fraktalnych na naturalną porowatość pękniętych skał, ich przepuszczalność oraz pozostałe właściwości. Wyniki badań wskazują że, po pierwsze, liczba i tempo propagacji naturalnych spękań uzależnione są od wymiarów fraktalnych, liczby grup i wielkości początkowej. Po drugie, wymiary fraktalne naturalnego systemu spękań skał mają zdecydowany wpływ na porowatość i przepuszczalność. Po trzecie, porowatość i przepuszczalność naturalnych systemów pęknięć wykazują wzrost w miarę wzrastania wymiarów fraktalnych. Po czwarte, gdy wymiary fraktalne pozostają niezmienne, zarówno porowatość i przepuszczalność naturalnych spękań rosną wraz ze skalą fraktali.
Źródło:
Archives of Mining Sciences; 2018, 63, 2; 425-436
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The 3-Rainbow Index of a Graph
Autorzy:
Chen, Lily
Li, Xueliang
Yang, Kang
Zhao, Yan
Powiązania:
https://bibliotekanauki.pl/articles/31339122.pdf
Data publikacji:
2015-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow tree
S-tree
k-rainbow index
Opis:
Let $G$ be a nontrivial connected graph with an edge-coloring $c : E(G) → {1, 2, . . ., q}, q ∈ ℕ$, where adjacent edges may be colored the same. A tree $T$ in $G$ is a rainbow tree if no two edges of $T$ receive the same color. For a vertex subset $S ⊆ V (G)$, a tree that connects $S$ in $G$ is called an $S$-tree. The minimum number of colors that are needed in an edge-coloring of $G$ such that there is a rainbow $S$-tree for each $k$-subset $S$ of $V(G)$ is called the $k$-rainbow index of $G$, denoted by $rx_k(G)$. In this paper, we first determine the graphs of size $m$ whose 3-rainbow index equals $m$, $m − 1$, $m − 2$ or $2$. We also obtain the exact values of $rx_3(G)$ when $G$ is a regular multipartite complete graph or a wheel. Finally, we give a sharp upper bound for $rx_3(G)$ when $G$ is 2-connected and 2-edge connected. Graphs $G$ for which $rx_3(G)$ attains this upper bound are determined.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 1; 81-94
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs with 3-Rainbow Index n − 1 and n − 2
Autorzy:
Li, Xueliang
Schiermeyer, Ingo
Yang, Kang
Zhao, Yan
Powiązania:
https://bibliotekanauki.pl/articles/31339126.pdf
Data publikacji:
2015-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow S-tree
k-rainbow index
Opis:
Let $G = (V(G),E(G))$ be a nontrivial connected graph of order $n$ with an edge-coloring $c : E(G) → {1, 2, . . ., q}, q ∈ \mathbb{N}$, where adjacent edges may be colored the same. A tree $T$ in $G$ is a rainbow tree if no two edges of $T$ receive the same color. For a vertex set $S ⊆ V (G)$, a tree connecting $S$ in $G$ is called an $S$-tree. The minimum number of colors that are needed in an edge-coloring of $G$ such that there is a rainbow $S$-tree for each $k$-subset $S$ of $V(G)$ is called the $k$-rainbow index of $G$, denoted by $rx_k(G)$, where $k$ is an integer such that $2 ≤ k ≤ n$. Chartrand et al. got that the $k$-rainbow index of a tree is $n−1$ and the $k$-rainbow index of a unicyclic graph is $n−1$ or $n−2$. So there is an intriguing problem: Characterize graphs with the $k$-rainbow index $n − 1$ and $n − 2$. In this paper, we focus on $k = 3$, and characterize the graphs whose $3$-rainbow index is $n − 1$ and $n − 2$, respectively.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 1; 105-120
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on disturbance rejection control strategy of vehicle drive axle loading test bench
Autorzy:
Yu, Hui
Wang, Hui
Li, Nanqi
Zhao, Guochao
Powiązania:
https://bibliotekanauki.pl/articles/2086968.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
loading test-bed
disturbance
adaptive backstepping sliding mode control
overshoot
sinusoidal tracking error
Opis:
Aiming at the problems of parameter disturbance and coupling disturbance in a vehicle drive axle loading test-bed, this paper used the adaptive backstepping sliding mode control (ABSMC) strategy to design the controller for the speed and torque system. The effectiveness of the controller has been verified by simulation and an experiment. The results show that the equivalent moment of inertia is increased by 5 times, and the step response overshoot of the speed system is 4.1%. By adding a random disturbance, the sinusoidal tracking errors of the speed and torque systems are 0.05 r/min and 0.09Nm, respectively.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 2; 227--238
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Matched-field Source Localization with a Mobile Short Horizontal Linear Array in Offshore Shallow Water
Autorzy:
Zhao, D.
Huang, Z.
Su, S.
Li, T.
Powiązania:
https://bibliotekanauki.pl/articles/177986.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
passive source localization
matched-field processing
inter-position processing
short horizontal array
shallow water
Opis:
Passive source localization in shallow water has always been an important and challenging problem. Implementing scientific research, surveying, and monitoring using a short, less than ten meter long, horizontal linear array has received considerable attention in the recent years. The short array can be conveniently placed on autonomous underwater vehicles and deployed for adaptive spatial sampling. However, it is usually difficult to obtain a sufficient spatial gain for localizing long-range sources due to its limited physical size. To address this problem, a localization approach is proposed which is based on matched-field processing of the likelihood of the passive source localization in shallow water, as well as inter-position processing for the improved localization performance and the enhanced stability of the estimation process. The ability of the proposed approach is examined through the two-dimensional synthetic test cases which involves ocean environmental mismatch and position errors of the short array. The presented results illustrate the localization performance for various source locations at different signal- to-noise ratios and demonstrate the build up over time of the positional parameters of the estimated source as the short array moves at a low speed along a straight line at a certain depth.
Źródło:
Archives of Acoustics; 2013, 38, 1; 105-113
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of antibacterial polyurethane film and its properties
Autorzy:
Lin, Zhao
Yunyun, Li
Bin, Cheng
Yu, Chen
Powiązania:
https://bibliotekanauki.pl/articles/779374.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
polyurethane
Ag nanoparticles
antibacterial
composite film
Opis:
Polyurethane (PU) is a polymer widely used in the biomedical field with excellent mechanical properties and good biocompatibility. However, it usually exhibits poor antibacterial properties for practical applications. Efforts are needed to improve the antibacterial activities of PU films for broader application prospect and added application values. In the present work, two PU films, TDI-P(E-co-T) and TDI-N-100-P(E-co-T), were prepared. Silver nanoparticles (AgNPs) were composited into the TDI-N-100-P(E-co-T) film for better mechanical properties and antibacterial activities, and resultant PU/AgNPs composite film was systematically characterized and studied. The as-prepared PU/AgNPs composite film exhibits much better antibacterial properties than the traditional PU membrane, exhibiting broader application prospect.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 2; 50-55
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of colloidal montmorillonite particles on froth flotation of graphite, galena and fluorite
Autorzy:
Chen, T.
Zhao, Y.
Li, H.
Song, S.
Powiązania:
https://bibliotekanauki.pl/articles/110589.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
montmorillonite
graphite
galena
fluorite
slime coating
entrainment
Opis:
The effect of colloidal montmorillonite (MMT) on froth flotation of graphite, galena and fluorite was investigated in this work. The results showed that the presence of sufficient amount of colloidal MMT particles in the mineral slurry would be detrimental of flotation by reducing the recovery of minerals. This observation was attributed to slime coating of MMT on the coarse valuable mineral particles and entrainment of MMT particles in the froth product together with water in the triangle froth zones. The former would reduce the recovery of the valuable minerals because of hydrophilic MMT coating. The latter would decrease the concentrate grade. The degree of slime coating depended on slurry pH, while the degree of entrainment was closely related to water recovery. It was also found that slime coating was a dominant factor in mineral flotation in acidic pH regions in the presence of colloidal MMT particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 699-713
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Static Unbalance Analysis and Its Measurement System For Gimbals Axes of an Inertial Stabilization Platform
Autorzy:
Yang, H.
Zhao, Y.
Li, M.
Wu, F.
Powiązania:
https://bibliotekanauki.pl/articles/221513.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inertial stabilization platform
mass eccentricity
angular position turntable
dynamical model
least-square fitting
Opis:
To reduce the influence of the static unbalance on an infrared missile guidance system, a new static unbalance measure system for the gimbals axes has been developed. Considering the coupling effects caused by a mass eccentricity, the static balance condition and measure sequence for each gimbal axis are obtained. A novel static unbalance test approach is proposed after analyzing the dynamic model of the measured gimbal axis. This approach is to drive the measured gimbal axis to do sinusoidal reciprocating motion in a small angle and collect its drive currents in real time. Then the static unbalance of the measured gimbal axis can be obtained by the current multi-cycle integration. Also a measuring system using the proposed approach has been developed. A balanced simulator is used to verify the proposed approach by the load and repeatability tests. The results show the proposed approach enhances the efficiency of the static unbalance measurement, and the developed measuring system is able to achieve a high precision with a greater stability.
Źródło:
Metrology and Measurement Systems; 2015, 22, 1; 51-68
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs with 4-Rainbow Index 3 and n − 1
Autorzy:
Li, Xueliang
Schiermeyer, Ingo
Yang, Kang
Zhao, Yan
Powiązania:
https://bibliotekanauki.pl/articles/31339468.pdf
Data publikacji:
2015-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow S-tree
k-rainbow index
Opis:
Let $G$ be a nontrivial connected graph with an edge-coloring $ c : E(G) \rightarrow $ $ {1, 2, . . ., q}, $ $q \in \mathbb{N} $, where adjacent edges may be colored the same. A tree $T$ in $G$ is called a rainbow tree if no two edges of $T$ receive the same color. For a vertex set $ S \subseteq V (G) $, a tree that connects $S$ in $G$ is called an $S$-tree. The minimum number of colors that are needed in an edge-coloring of $G$ such that there is a rainbow $S$-tree for every set $S$ of $k$ vertices of $V (G)$ is called the $k$-rainbow index of $G$, denoted by $ r x_k (G) $. Notice that a lower bound and an upper bound of the $k$-rainbow index of a graph with order $n$ is $k − 1$ and $n − 1$, respectively. Chartrand et al. got that the $k$-rainbow index of a tree with order $n$ is $n − 1$ and the $k$-rainbow index of a unicyclic graph with order $n$ is $n − 1$ or $n − 2$. Li and Sun raised the open problem of characterizing the graphs of order $n$ with $r x_k (G) = n − 1$ for $ k \ge 3 $. In early papers we characterized the graphs of order $n$ with 3-rainbow index 2 and $n − 1$. In this paper, we focus on $k = 4$, and characterize the graphs of order $n$ with 4-rainbow index 3 and $n − 1$, respectively.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 2; 387-398
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bearing capacity and seismic performance of Y-shaped reinforced concrete bridge piers in a freeze-thaw environment
Autorzy:
Li, Yanfeng
Li, Jialong
Guo, Tianyu
Zhao, Tongfeng
Bao, Longsheng
Sun, Xinglong
Powiązania:
https://bibliotekanauki.pl/articles/2203435.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
A quantitative study is performed to determine the performance degradation of Y-shaped reinforced concrete bridge piers owing to long-term freeze-thaw damage. The piers are discretized into spatial solid elements using the ANSYS Workbench finite element analysis software, and a spatial model is established. The analysis addresses the mechanical performance of the piers under monotonic loading, and their seismic performance under low-cycle repeated loading. The influence of the number of freeze-thaw cycles, axial compression ratio, and loading direction on the pier bearing capacity index and seismic performance index is investigated. The results show that freeze-thaw damage has an adverse effect on the ultimate bearing capacity and seismic performance of Y-shaped bridge piers in the transverse and longitudinal directions. The pier peak load and displacement ductility coefficient decrease with increasing number of freeze-thaw cycles. The axial compression ratio is an important factor that affects the pier ultimate bearing capacity and seismic performance. Upon increasing the axial compression ratio, the pier peak load increases and the displacement ductility coefficient decreases, the effects of which are more significant in the longitudinal direction.
Źródło:
Archives of Civil Engineering; 2023, 69, 1; 367--384
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of Clothing Tactile Comfort Based on Electro-neurophysiology
Eksperymentalne badanie komfortu dotykowego odzieży na podstawie elektroneuro fizjologii
Autorzy:
Wang, Y
Zhao, M M
Yu, M
Li, J
Powiązania:
https://bibliotekanauki.pl/articles/231787.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
tactile
clothing
electromyography
electroencephalography
dotykowy comfort odzieży
elektromiografia
elektroencefalografia
Opis:
Electromyography (EMG) and electroencephalography (EEG) methods were used to evaluate the reaction of human skin to tactile stimuli evoked by textiles. The peak value of the EMG and energy percentage of the weave of the EEG when the subjects came into contact with 9 kinds of fabrics were selected for tests and next clothing was made on their basis. They were utilized as two important evaluating indexes. Statistical analysis was carried out to verify the correlation between the data obtained from objective measurements and the subjective measurements. The results showed that when the subjects came into contact with thicker, heavier and stiffer fabrics, the peak values of the myoelectric potential induced were higher. When clothing with a higher mass density was worn, energy percentages of the weave at both the left and right occipitalia were higher.
Dla oceny reakcji ludzkiej skóry na dotykowe stymulacje materiałami włóknistymi stosowano elektromiografię (EMG) i elektroencefalografie (EEG). Wartość szczytowa przebiegu EMG oraz procent energii fali EEG w czasie kiedy badane osoby znajdowały się w kontakcie z 9 rodzajami materiałów włókienniczych posłużyła do ich selekcji dla stosowanych testów. Na tej podstawie wykonano odzież przeznaczona dla osób testowanych. Przeprowadzono analizę statystyczna dla zweryfikowania korelacji pomiędzy wynikami uzyskanymi z obiektywnych pomiarów oraz subiektywnych testów. Wyniki wykazały, że kiedy osoby badane znajdowały się w kontakcie z grubszymi i cięższymi i sztywniejszymi materiałami to wartość piku EMG była wyższa. Kiedy ubranie wykonane było z udziałem przędz o wyższej masie liniowej procent energii fali lewej i prawej połówki potylicy był wyższy.
Źródło:
Fibres & Textiles in Eastern Europe; 2014, 4 (106); 102-106
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on speed control of high speed trains based on hybrid modeling
Autorzy:
Hou, Tao
Tang, Li.
Niu, Hong-xia
Zhao, Tingyang
Powiązania:
https://bibliotekanauki.pl/articles/27311802.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
high-speed train
hybrid modeling
speed control
error compensation
pociąg ekspresowy
modelowanie hybrydowe
kontrola prędkości
kompensacja błędów
Opis:
With the continuous improvement of train speed, the automatic driving of trains instead of driver driving has become the development direction of rail transit in order to realize traffic automation. The application of single modeling methods for speed control in the automatic operation of high-speed trains lacks exploration of the combination of train operation data information and physical model, resulting in low system modeling accuracy, which impacts the effectiveness of speed control and the operation of high-speed trains. To further increase the dynamic modeling accuracy of high-speed train operation and the high-speed train's speed control effect, a high-speed train speed control method based on hybrid modeling of mechanism and data drive is put forward. Firstly, a model of the high-speed train's mechanism was created by analyzing the train's dynamics. Secondly, the improved kernel-principal component regression algorithm was used to create a data-driven model using the actual operation data of the CRH3 (China Railway High-speed 3) high-speed train from Huashan North Railway Station to Xi'an North Railway Station of "Zhengxi High-speed Railway," completing the mechanism model compensation and the error correction of the speed of the actual operation process of the high-speed train, and realizing the hybrid modeling of mechanism and data-driven. Finally, the prediction Fuzzy PID control algorithm was developed based on the natural line and train characteristics to complete the train speed control simulation under the hybrid model and the mechanism model, respectively. In addition, analysis and comparison analysis were conducted. The results indicate that, compared to the high-speed train speed control based on the mechanism model, the high-speed train speed control based on hybrid modeling is more accurate, with an average speed control error reduced by 69.42%. This can effectively reduce the speed control error, improve the speed control effect and operation efficiency, and demonstrate the efficacy of the hybrid modeling and algorithm. The research results can provide a new ideal of multi-model fusion modeling for the dynamic modeling of high-speed train operation, further improve control objectives such as safety, comfort, and efficiency of high-speed train operation, and provide a reference for automatic driving and intelligent driving of high-speed trains.
Źródło:
Archives of Transport; 2023, 66, 2; 77--82
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Welding Heat Input on Microstructure and Corrosion Characterization in CGHAZ of X80 Pipeline Steel
Autorzy:
Wang, Xue-Mei
Zhao, Wei
Chen, Kai
Li, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/28099607.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
X80 pipeline steel
coarse grain heat-affected zone
heat input
corrosion
Opis:
The coarse-grained heat-affected zone specimens of X80 pipeline steel were produced by welding thermal simulation under different heat inputs of 10, 30, and 55 kJ/cm to study the effects of heat input on microstructure evolution and corrosion characterization. The corrosion resistance of coarse-grained heat-affected zones was poorer than that of base metal due to less homogenous in the former. For 10 kJ/cm coarse-grained heat-affected zone, the corrosion resistance was poorer than the others due to the more adsorption hydrogen around the needle-like martensite/austenite constituents and greater galvanic driving force between the needle-like martensite/austenite constituents and ferrite. In carbonate/bicarbonate solution, better corrosion resistance for coarse-grained heat-affected zones was obtained when the heat input is 30 kJ/cm, which can be attributed to the severe coarse martensite/austenite constituents for 55 kJ/cm coarse-grained heat-affected zone. In the H2S environment, the better corrosion resistance for coarse-grained heat-affected zone was obtained when the heat input is 55 kJ/cm, which can be attributed to the protective effect of corrosion products. In addition, the high content of M/A constituents for 30 kJ/cm CGHAZ was good for hydrogen adsorption, which was adverse to the corrosion resistance in acid environments.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 659--671
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital watermarking algorithm based on 4-level discrete wavelet transform and discrete fractional angular transform
Autorzy:
Li, Jing-You
Zhao, Chun-Hui
Zhang, Guang-Da
Powiązania:
https://bibliotekanauki.pl/articles/2033921.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital watermarking algorithm
mix optical bistability
Harris feature point detection
discrete wavelet transform
discrete fractional angular transform
singular value decomposition
Opis:
Nowadays, there are many watermarking algorithms based on wavelet transform. The simple one is to insert directly the watermark into the wavelet transform coefficients. However, most of the existing watermarking schemes can only resist traditional signal processing attacks, such as image compression, noise and filtering. When the watermarked image is subject to geometric transformations, especially rotation attack, it is hard to detect the watermark successfully. In this paper, a digital watermarking algorithm is proposed based on 4-level discrete wavelet transform and discrete fractional angular transform. To enhance the security of the algorithm, the watermark is scrambled with the simplicity of Arnold transform and chaos-based mix optical bistability model, since the chaos is pseudorandom and sensitive to the initial values. And the watermark is embedded into the medium frequency sub-band of the 1-level wavelet decomposition according to the Harris feature point detection. Simulation results show that the proposed digital watermarking algorithm by combining 4-level discrete wavelet transform with discrete fractional angular transform could resist rotation attack and other common attacks.
Źródło:
Optica Applicata; 2021, 51, 4; 605-619
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic stability of a stepped drillstring conveying drilling fluid
Autorzy:
Zhao, G.-H.
Tang, S.
Liang, Z.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/280899.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
drill string
stepped fluid-conveying pipe
complex frequency
stability
FEM
Opis:
Taking into account differences between a drill pipe (DP) and a drill collar (DC), the drillstring in a vertical well is modeled as a stepped pipe conveying a drilling fluid downwards to the bottom inside the string and then upwards to the ground from the annulus. An analytical model that describes lateral vibration of the drillstring and involves the drillstring gravity, weight on bit (WOB), hydrodynamic force and damping force of the drilling fluid is established. By analysis of complex frequencies, the influences of WOB, borehole diameter, DP length, velocity and density of the drilling fluid on the stability of the system are discussed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 4; 1409-1422
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
H2 and syngas production from catalytic cracking of pig manure and compost pyrolysis vapor over Ni-based catalysts
Autorzy:
Li, W.
Ren, J.
Zhao, X.-Y.
Takarada, T.
Powiązania:
https://bibliotekanauki.pl/articles/778243.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Catalytic gasification
Pig manure
Compost
Ni-based catalyst
Opis:
Catalytic cracking of volatiles derived from wet pig manure (WPM), dried pig manure and their compost was investigated over Ni/Al2O3  and Ni-loaded on lignite char (Ni/C). Non-catalytic pyrolysis of WPM resulted in a carbon conversion of 43.3% and 18.5% in heavy tar and light tar, respectively. No tar was formed when Ni/Al2O3  was introduced for WPM gasification and the gas yield significantly reached to a high value of 64.4 mmol/g at 650°C. When Ni/C was employed, 5.9% of carbon in the light tar was found at 650°C, revealing that the Ni/C is not active enough for cracking of tarry materials. The pyrolysis vapor was cracked completely and gave a H2-rich tar free syngas in high yield. High water amount of WPM promotes steam gasification of char support, causing the deactivation of Ni/C. Such a study may be beneficial to the development of livestock manure catalytic gasification technology.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 3; 8-14
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural filling and systematic roof control technology for gob-side entry retaining in steep coal seams
Naturalne podsadzanie stropu i metoda systemowego prowadzenia stropu przy utrzymaniu chodników przewozowych od strony zrobów w nachylonych pokładach węgla
Autorzy:
Yang, H.
Cao, S.
Zhou, G.
Zhao, Y.
Li, G.
Li, Y.
Fan, Y.
Powiązania:
https://bibliotekanauki.pl/articles/220162.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
utrzymanie chodnika przewozowego
nachylone pokłady węgla
naturalne podsadzanie
projekt systemowy
gob-side entry retaining
steep coal seams
natural filling
systematic project
Opis:
The technology for gob-side entry retaining in steep coal seams is still in the development stage. The analysis results of the caving structure of main roof, low influence of gateway’s stability because of long filling distance and weak dynamic effect of the gateway, and the low stress redistribution environment indicate that using this technology in steep coal seams has significant advantages. Moreover, to reinforce the waste rock and the soft floor and to better guard against the impact of the waste rock during natural filling, a rock blocking device and grouting reinforcement method were invented, and theoretical calculations result show that the blocking device has high safety factor. In addition, we also developed a set of hydraulic support devices for use in the strengthening support zone. Furthermore, because the retaining gateway was a systematic project, the selection of the size and shape of the gateway cross section and its support method during the initial driving stage is a key step. Thus, first, a section the size of bottom width and roof height of a new gateway was determined to meet any related requirements. Then, according to the cross sections of 75 statistical gateways and the support technique, it chosen a trapezoidal cross section when the dip of the coal seam is […], a special and an inclined arch cross section when […]. Eventually, a support system of bolts and cables combined with steel mesh and steel belts was provided. The support system used optimized material and improved parameters, can enhanced the self-bearing ability of the surrounding coal and rock masses.
Technologia utrzymywania chodników w obszarze zrobów w nachylonych pokładach węgla jest nadal rozwijana i udoskonalana. Jej zastosowanie prowadzi do zawału głównego stropu, który jednak w nieznacznym tylko stopniu wpływa na stabilność chodników z uwagi na odległość obszaru podsadzania, podczas gdy oddziaływania dynamiczne na chodniki przewozowe będą niewielkie. Powstały rozkład naprężeń wskazuje, że zastosowanie tej technologii w stromych pokładach przyniesie znaczne korzyści. Ponadto, w celu wzmocnienia warstw skał płonnych i miękkich warstw spągowych, a także dla lepszego zabezpieczenia przed skutkami ruchów skał płonnych w trakcie podsadzania, opracowano urządzenia blokujące ruch skał wraz ze wzmocnieniem cementowym. Obliczenia teoretyczne wskazują że zastosowana blokada ruchów skał charakteryzuje się wysokim wskaźnikiem bezpieczeństwa. Ponadto, opracowano także zestaw wsporników hydraulicznych dla dodatkowego wzmocnienia strefy podsadzania. Z uwagi na to, że zachowanie chodnika przewozowego jest działaniem stałym i systematycznym, dobór wymiarów i kształtu przekroju chodnika oraz metody jego stabilizacji jest sprawą kluczową już na etapie drążenia chodnika. W kroku pierwszym określono więc szerokość chodnika w jego dolnej części oraz wysokość stropu zgodnie z odpowiednimi wymogami. Następnie w oparciu o wymiary przekrojów 75 statystycznych chodników oraz uwzględniając dostępne techniki stabilizacji stropu wybrano przekrój trapezoidalny gdy nachylenie pokładu węgla mieści się w przedziale […], zaś dla kątów nachylenia w przedziale […] wybrano nachylony profil łukowy. W etapie końcowym zastosowano układ stabilizujący oparty na kotwach i kablach połączonych siatka stalową i stalowymi taśmami. W systemie stabilizującym wykorzystano zoptymalizowane materiały zapewniając lepsze parametry pracy, co korzystanie wpłynie na nośność warstw górotworu w otoczeniu pokładu węgla.
Źródło:
Archives of Mining Sciences; 2018, 63, 3; 599-616
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on triboelectrostatic beneficiation of wet fly ash using Microwave Heating
Autorzy:
Li, H.
Chen, Y.
Zhang, X.
Zhao, Y.
Tao, Y.
Li, C.
He, X.
Powiązania:
https://bibliotekanauki.pl/articles/110399.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wet fly ash
triboelectrostatic beneficiation
microwave heating
efficiency
Opis:
Triboelectrostatic beneficiation, as a physical method, of fly ash cannot only meet the technical requirements of fly ash application but also recycle of an unburned carbon as a useful energy source. The aim of this study was to investigate the feasibility of improving efficiency of triboelectrostatic beneficiation of wet fly ash using microwave heating. The wet fly ash with different moisture contents had an average loss-on-ignition of 12.56%. The fly ash samples were heated in a microwave oven before the experiments. The experimental conditions were electric field voltage of 40 kV and air flux ranging from 12 to 30 m3/h. The influence of the microwave heating on the wet fly ash triboelectrostatic beneficiation was discussed under the conditions of different microwave intensity and irradiation time. The results indicated that the removal rate and recycle rate of the unburned carbon showed a significant increase performance as the wet fly ash was processed by the microwave heating which was attributed to changes of moisture contents and dielectric constants caused by the microwave heating. The feasibility had been verified according to the experimental study on fly ash with different moisture contents. It can be concluded that the microwave heating process was efficiently applied for the wet fly ash triboelectrostatic beneficiation.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 328-341
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 134

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