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Tytuł:
Effects of U-shaped two-step throttling groove parameters on cavitation erosion characteristics
Autorzy:
Jia, Wenhua
Liu, Yanyan
Yin, Chenbo
Li, Guo
Zhu, Dasheng
Ding, Shen
Powiązania:
https://bibliotekanauki.pl/articles/2055063.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
avitation erosion
throttling groove
distribution coefficient
Opis:
Throttling usually occurs when a fluid passes through an orifice, sometimes even severe cav- itation erosion may occur. In this study, the equation for the cavitation index of a throttling valve was proposed and the cavitation erosion area in the throttle valve was found to change its position with the orifice opening (X). Cavitation features of singular and two-port se- ries throttling grooves were characterized by defining cavitation indexes σ1and σ2, because the cavitation index-σ can determine the occurrence and intensity of cavitation. Then the indexes σ1 and σ2 included internal geometric parameters and external pressure boundaries were obtained, and cavitation indexes curves σ1-X and σ2-X were also plotted. From the curves of the cavitation index, it was observed that cavitation concentration section also would transfer with opening X changes in the U-shaped groove. The depth of the U-shaped groove had a more evident impact on cavitation, whereas the effect of width on cavitation erosion was not so obvious. The intensity of cavitation erosion when the fluid flowed into the orifice section of the U-shaped groove was always larger than that when the fluid flowed away.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 4; 529--538
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-Principles Calculations for Structural, Elastic, Electronic and Thermodynamic Properties of $HfZn_{2}$ under Pressure
Autorzy:
Li, Guo-Jun
Shi, Lan-Ting
Hu, Cui-E
Cheng, Yan
Ji, Guang-Fu
Powiązania:
https://bibliotekanauki.pl/articles/1398192.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
C15 Laves-phase
elastic properties
electronic structure
vibrational properties
quasi-harmonic approximation
Opis:
By using density functional theory within the Perdew-Burke-Ernzerhof generalized gradient approximation implemented in the VASP code, we study the structural, elastic, electronic, and thermodynamic properties of C15 Laves-phase compound $HfZn_{2}$. Comparing the lattice constants calculated from the Perdew-Burke-Ernzerhof generalized gradient approximation and local density approximation, we find that the former is in better agreement with the experimental data. The elastic constants of $HfZn_{2}$ calculated by strain-stress method indicate that they keep stable up to 100 GPa. The bonding characteristics are discussed by analyzing the energy band structure, charge density distribution and charge density difference. Phonon dispersion curves and phonon density of states of HfZn_{2} at the different pressure are predicted for the first time. In addition, there is no imaginary frequency in the phonon band at different pressure, which also shows that $HfZn_{2}$ is stable up to 100 GPa. Vibrational models are also illustrated based on phonon and group theory. The thermodynamic properties under high temperature and high pressure are calculated by different thermodynamic models. The heat capacity at constant pressure and low temperature calculated by quasi-harmonic approximation is more close to the measurement than that calculated by quasi-harmonic Debye models.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1299-1306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Counterion effects on the alkali dissolution mechanism of quartz
Autorzy:
Yao, Yu-yun
Tang, Yun
Yang, Yong
Li, Guo-hui
Wu, Bo
Dai, Wen-zhi
Powiązania:
https://bibliotekanauki.pl/articles/2200337.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz
counterion
quantum chemistry
hydrolysis
mechanism
Opis:
In gold ore, quartz plays an important role in mineral formation by acting as the follower. Understanding counterion release, transport, and deposition in alkali solution is a prerequisite for evaluating the potential role of gold separate from quartz deposits in pretreatment. In this work, the aggregation, retention, and release of counterion in alkali solution media were investigated by kinetic research and pure mineral experiments, the correlation and mechanism of these processes were revealed by combining geochemical theory, interaction energy calculation, and quantum chemistry. The results showed that the retention and release of counterion were closely related to the dissolution and corrosion rate of quartz. The NH4+ and Fe2+ with higher mineral affinity reduced the quartz stability, and the dispersion stability and mobility of the quartz were greatly improved by an alkaline substance due to the enhancement of steric hindrance effects. Quantum chemical calculation results show that ammonium ion promotes the dissolution of quartz stronger than ferrous ion, which is mainly reflected in reducing the activation energy required for the formation of transition state (TS1), which can be verified by kinetic calculation. These findings provide essential insight into the extraction of gold coated by quartz as well as a vital reference for the experiment of gold-loaded quartz leaching in mineral processing.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 160038
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A modified model of residual strength prediction for metal plates with through-thickness cracks
Autorzy:
Li, Yanping
Wang, Jianjun
Guo, Weiguo
Guo, Jin
Powiązania:
https://bibliotekanauki.pl/articles/281643.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
residual strength
damage degree factor
crack
multiple site damage
Opis:
A new model, accurate and easy-to-apply, has been proposed to predict the residual strength for metal plates intact or with different damage degrees. In this model, we introduced the damage degree factor (DDF) to quantify the initial damage condition of a plate. The middle crack tension (M(T)) tests and multiple site damage (MSD) tension tests were performed on plate specimens in aluminum alloy LY12-CZ and 2524-T3, respectively. For various damage degrees, the predicted results of this new model showed an improved correlation with test results compared to the net section yield criterion, K-apparent criterion and Duong’s method.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 537-547
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Performance of CL-20-based Ultraviolet-curable High-explosive Ink and Its Application in Rigid Explosive Networks by Direct Ink Writing
Autorzy:
Li, Rui
Li, Weibing
Guo, Xiaode
Liang, Li
Wang, Yajun
Li, Weibin
Powiązania:
https://bibliotekanauki.pl/articles/27787838.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
multi-point initiation explosive network
UV-curability highexplosive ink
direct ink writing/printing
initiation synchronicity error
precise press-loading charge
Opis:
To improve the groove charge consistency and density and to reduce the initiation synchronicity error of a rigid multi-point initiation explosive network, a CL-20-based ultraviolet (UV)-curable high-explosive ink, comprising 42 wt.% sub-micron CL-20, a 55.4 wt.% binder system (including 2.0 wt.% NC and 53.4 wt.% butyl acetate), and 2.6 wt.% UV-curable resin, based on direct ink writing (DIW) technology, was prepared. The properties of the composite sample deposited via DIW were characterized. The results indicated that the sample had good uniformity, with few defects, and a critical detonation size of around 1.5×0.283 mm. A six-point initiation explosive network was designed for the integration of DIW technology and precise press-loading of the charge. The network featured six pre-pressed booster pellets with the same charge density (ρ0 = 1.89 g·cm−3, 95.8% of theoretical maximum density) as the output end charges, and a groove channel charged by DIW and press-loading. This procedure increased the density of the booster charge in the groove channels to 1.890 g·cm−3, effectively improved the consistency of the charge density between the groove channels and the output ends and lowered the initiation synchronicity error of the network to 62 ns. The network can initiate a jetting projectile charge (JPC) with good shape and small lateral offset, implying that the network initiation capability and synchronization meet the operational requirements of JPC shaped charges.
Źródło:
Central European Journal of Energetic Materials; 2021, 18, 1; 86--111
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on emergency DC power support coordinated control for hybrid multi-infeed HVDC system
Autorzy:
Li, Congshan
Li, Yikai
Guo, Jian
He, Ping
Powiązania:
https://bibliotekanauki.pl/articles/140422.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
additional controllers
coordinated control
EDCPS
hybrid multi-infeed HVDC system
HVDC
Opis:
Based on the respective characteristics of line-commutated converter highvoltage direct current (LCC-HVDC) and voltage-source converter high voltage direct current (VSC-HVDC), two additional emergency DC power support (EDCPS) controllers are designed, respectively. In addition a coordinated control strategy based on a hybrid multi-infeed HVDC system for EDCPS is proposed. Considering the difference in system recovery between LCC-HVDC and VSC-HVDC in EDCPS, according to the magnitude of the amount of potential power loss, the LCC-HVDC and VSC-HVDC priority issues of boosting power for EDCPS are discussed in detail. Finally, a hybrid three-infeed HVDC that consists of two parallel LCC-HVDCs and one VSC-HVDC that is built in PSCAD/EMTDC are simulated. The effectiveness of the proposed approach is verified based on this hybrid three-infeed HVDC system.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 5-21
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of out-of-plane free vibration of single damaged curved beam based on precise algorithm of structural mechanics
Autorzy:
Li, Xiaofei
Pan, Zhouyang
Guo, Hainan
Powiązania:
https://bibliotekanauki.pl/articles/2200899.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
out-of-plane curved beam
damaged
stiffness matrix
free vibration
Opis:
Based on a dynamic discrete model of an out-of-plane curved beam with a constant cur- vature, eigen-properties of the spatial curved beam structure in undamaged and damaged configurations are considered in this paper. In the literature, based on the equivalent sec- tion reduction method, a distributed damage modeling method is proposed. Accoding to Euler-Bernoulli beam theory, the stiffness matrix of shear, bending and torsion coupling is derived. Combined with the lumped mass matrix and the characteristic equation of the multi degree of freedom system, natural frequencies of the undamaged and damaged structures are calculated.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 407--414
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The synergistic effect of boric acid and ammonium polyphosphate on the thermal degradation and flammability of pine-needles
Autorzy:
Li, L.
Hu, H.
Guo, C.
Powiązania:
https://bibliotekanauki.pl/articles/52633.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
synergistic effect
boric acid
ammonium polyphosphate
thermal degradation
flammability
pine needle
needle
pyrolysis
temperature
flame retardant
Opis:
The synergistic effect of ammonium polyphosphate (APP) and boric acid (BA) on the flame retardancy and thermal degradation of pine needles was investigated. Thermogravimetric analysis (TGA) showed that the presence of an ammoniumpolyphosphate and boric acid system increased the char residue and decreased the pyrolysis temperature of the pine needles. The derivative thermogravimetric analysis (DTG) showed that the ammonium polyphosphate and boric acid had shifted the degradation peaks of the pine needles to lower temperatures. The cone calorimetry test results showed that the values of HRR, THR, SPR, TSP and the mass loss (%) of the pine needles treated with ammonium polyphosphate and boric acid (APP/BA = 3/2)were significantly lower than the other samples. Therefore, the APP and BA system had a better effect on the pine needles overall than the APP alone.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2014, 57, 193
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomechanical and fluid flowing characteristics of intervertebral disc of lumbar spine predicted by poroelastic finite element method
Autorzy:
Guo, L.-X
Li, R.
Zhang, M.
Powiązania:
https://bibliotekanauki.pl/articles/307246.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kręgosłup lędźwiowy
poroelastyczność
FEM
lumbar spine
poroelastic finite element model
intermittent compressive load
permeability of cartilage endplate
Opis:
Purpose: This study is to reveal the deformation of intervertebral disc (IVD), the stress distribution of solid phase and liquid phase, the variation of fluid flux and flow velocity in lumbar spine and the influence of different permeability parameters on them under intermittent compressive loading. Methods: A poroelastic FEM of L4-L5 is assigned with different permeability parameters to analyze the deformation, stress distribution and fluid convection under intermittent compressive loads. Results: The results show that the pore pressure of IVD decreases with time, but the effective stress increases under intermittent compressive loads. The axial and radial strain will increase and fluid loss will recover at a more rapid rate if the permeability of endplate increases during unloading period. The velocity vectors show that most of the liquid in the disc flows into vertebrae through endplates and only a small quantity of liquid flows through the annulus fibrosus at the loading step, however, at the unloading step, almost all the liquid flowing into IVD is through the endplates. Conclusions: The changing rate of pore pressure and effective stresses of nucleus pulposus and annulus fibrosus with higher permeability is smaller than that with smaller permeability. The degenerated endplate (with low permeability) yields high flow velocity decreasing gradient, which might impede liquid inflowing/outflowing smoothly through the endplates. The fluid flowing velocity in loading phase is faster than that in unloading phase, so a short resting time can relieve fatigue, but could not recover to the original liquid condition in IVDs.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 2; 19-29
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of a new type of Flettner rotor in merchant ships
Autorzy:
Li, Boyang
Zhang, Rui
Li, Yajing
Zhang, Baoshou
Guo, Chao
Powiązania:
https://bibliotekanauki.pl/articles/1573694.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship propulsion
flettner rotor
wind energy
rotating cylinder
numerical simulation
Opis:
Wind energy is a clean and renewable source of energy. This study seeks to explore the potential for utilising wind power for merchant ships. A new type of Flettner rotor (rotating cylinder) mounted on the superstructure of a ship is proposed and numerically simulated. The construction and installation of the rotating cylinder is designed and a numerical simulation of the ship-mounted cylinder is carried out, using the commercially available CFD code Ansys Fluent to obtain parameters such as lift and drag coefficient of the cylinder in different conditions. Specifically, it is found that the cylinder type superstructure can play a certain role in reducing the effect of friction by comparing traditional and cylindrical superstructures; the rotating cylinder can generate auxiliary thrust for the ship. After analysis, the wind speed around the cylinder and spin ratio will have a direct influence on its thrust effect; there is an inflection point in the lift coefficient with the increase of α; the thrust coefficient (8.63) reaches the maximum environmental wind speed at 10 m/s and spin ratio is 2.5. For the rotating cylinder, the greater the environmental wind, the greater the thrust contribution generated under the same spin ratio conditions. The maximum thrust can reach 750,000 N; the cylinder’s auxiliary propulsion contribution shows a better advantage in α = 2.0. The effective power generated by the cylinder reaches a maximum of 2,240 kW for environmental wind speed = 20 m/s and α = 1.0.
Źródło:
Polish Maritime Research; 2021, 1; 28-41
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Adjustable Thermal Insulations of Tibetan Clothing by Manikin Testing
Ocena możliwości zmian izolacji cieplnej ubiorów tybetańskich przy wykorzystaniu manekina
Autorzy:
Guo, X F
Wang, Y Y
Li, J
Powiązania:
https://bibliotekanauki.pl/articles/232266.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
Tibetan clothing
style
thermal insulation
clothing area factor
thermal manikin
ubiór tybetański
styl
izolacja cieplna
przewodzenie ciepła
manekin termiczny
Opis:
The thermal insulation of clothing needs to be easily adjusted in an unsteady environment, but this is extremely difficult for most clothing. To reveal the effect of different styles of Tibetan clothing on their thermal property, the total thermal insulations of Tibetan clothing in three typical styles were measured using a thermal manikin. The clothing area factors (fcl) of the Tibetan clothing and body surface area covered by a Tibetan robe were tested with a photographic method. The results showed the following: 1) For similar insulation, fcl of Tibetan clothing is about 0.23 bigger than that of western clothing, estimated from ISO 11079; 2)the style of Tibetan clothing significantly affects the fcl (p < 0.05, fcl = 1.229 + 0.007 BSAC) and the intrinsic thermal insulation (p < 0.05, Icl = 0.166 + 0.016 BSAC); 3)the adjustable thermal insulation of Tibetan clothing proved its adaptability to the large air temperature difference environment on the Tibetan plateau ,which should be valuable for the product development of clothing used in a unsteady environment.
Odzież powinna umożliwiać zmianę jej przewodności cieplnej w niestabilnym środowisku, jednak dla większości odzieży jest to niezwykle trudne. W celu określenia wpływu różnych stylów ubiorów tybetańskich na ich właściwości termiczne określono całkowitą izolację termiczna dla trzech typowych stylów odzieży tybetańskiej przy zastosowaniu manekina termicznego. Wpływ konfiguracji ubioru sprawdzono metodą fotograficzną za pomocą termowizji, określając jednocześnie powierzchniowy współczynnik okrycia ciała fcl. Wykazano, że 1) przy podobnej izolacji fcl ubiorów tybetańskich jest o 0.23 większy od ubiorów zachodnich (ISO11079); 2) styl ubiorów tybetańskich znacząco wpływa na fcl jak i wewnętrzną izolacje cieplną; 3) możliwość regulacji izolacji termicznej tybetańskiego ubioru zapewnia zdolność przystosowania się do dużych różnic temperatury otoczenia na płaskowyżu tybetańskim. Wyniki badań mogą znaleźć zastosowanie w projektowaniu odzieży noszonej w niestabilnym środowisku.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 1 (97); 87-91
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of force in single cable plane prestressed concrete polygonal line tower cable-stayed bridge based on minimum bending energy
Autorzy:
Li, Yanfeng
Guo, Tianyu
Bao, Longsheng
Wang, Fuchun
Powiązania:
https://bibliotekanauki.pl/articles/1852393.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The cable force of a cable-stayed bridge plays a vital role in its internal force state. Different cable forces on both sides of the main tower make the force characteristics of the polygonal-line tower quite different from those of the straight-line tower. Therefore, the determination of the cable force of the polygonal-line tower cable-stayed bridge is a crucial aspect of any evaluation of its mechanical characteristics. A single-cable plane prestressed concrete broken-line tower cable-stayed bridge is taken as a case study to conduct a model test and theoretical cable force determination. The reasonable cable force of the bridge is determined by the minimum bending energy method combined with false load and internal force balance methods. analysis includes a comparison between cable force calculation results, model test results, and the design value of the actual bridge. The distribution law of the dead load cable force of the completed bridge is determined accordingly.
Źródło:
Archives of Civil Engineering; 2021, 67, 3; 565-579
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution and sources of n-alkanes in surface sediments of Taihu Lake, China
Autorzy:
Yu, Y.
Li, Y.
Guo, Z.
Zou, H.
Powiązania:
https://bibliotekanauki.pl/articles/205298.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
n-alkanes
surface sediments
Taihu Lake
Opis:
The last study on n-alkanes in surface sediments of Taihu Lake was in 2000, only 13 surface sediment samples were analysed, in order to have a comprehensive and up-to-date understanding of n-alkanes in the surface sediments of Taihu Lake, 41 surface sediment samples were analyzed by GC-MS. C10 to C37 were detected, the total concentrations of n-alkanes ranged from 2109 ng g−1 to 9096 ng gg−1 (dry weight). There was strong odd carbon predominance in long chain n-alkanes and even carbon predominance in short chain n-alkanes. When this finding was combined with the analysis results of wax n-alkanes (WaxCn), carbon preference index (CPI), unresolved complex mixture (UCM), hopanes and steranes, it was considered that the long chain n-alkanes were mainly from terrigenous higher plants, and that the short chain n-alkanes mainly originated from bacteria and algae in the lake, compared with previous studies, there were no obvious anthropogenic petrogenic inputs. Terrestrial and aquatic hydrocarbons ratio (TAR) and C21−/C25+ indicated that terrigenous input was higher than aquatic sources and the nearshore n-alkanes were mainly from land-derived sources. Moreover, the distribution of short chain n-alkanes presented a relatively uniform pattern, while the long chain n-alkanes presented a trend that concentrations dropped from nearshore places to the middle of lake.
Źródło:
Archives of Environmental Protection; 2016, 42, 1; 49-55
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experiment of the monitoring prestress loss of prestressed concrete beams with damages under static loading
Autorzy:
Wang, Jinbo
Li, Guodong
Lan, Chunguang
Guo, Nan
Powiązania:
https://bibliotekanauki.pl/articles/2203451.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
In this paper, based on the feasible method and sensors for the full-scale prestressed monitor, the novel optical fiber sensors and the traditional monitoring sensors will be set up into two prestressed concrete beams with the same geometrical dimensions, material properties, and construction conditions, etc. to investigate the working state of the novel sensors and obtain the evolution law of prestress loss of the prestressed feature component under the static load. The results show that the evolution law of prestress loss of the loaded beam under the condition of no damage state and initial crack is the same as the non-loaded one; however, the prestress loss increases with the increase of time under the situation with the limit crack. The total loss of the prestressed beam with the limit crack is 36.4% without damage. The prestress loss of the prestressed beam under the static load increase with the development of the crack (injury).
Źródło:
Archives of Civil Engineering; 2023, 69, 1; 437--451
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Emission-intensity-enhanced GaN-based LED based on multilayer grating structures
Autorzy:
Li, Xin
Sun, Dejie
Han, Kun
Cao, Lijun
Guo, Shiliang
Li, Zhiquan
Powiązania:
https://bibliotekanauki.pl/articles/2033893.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
light-emitting diode
surface plasmon
grating
quantum well
Opis:
A novel surface-plasmon-enhanced GaN-LED is proposed to improve the emission efficiency of the traditional LED. The SiO2 film, Ag triangular structure and ITO film were coated on the rectangularly-patterned p-GaN layer sequentially, which can form the quasi-symmetrical waveguide structure to enhance the internal quantum efficiency and the light extraction efficiency. The COMSOL software is used to simulate the LED structure. The radiated powers, absorbed powers and distribution of electric field are obtained and analyzed. The results reveal that emission efficiency of the proposed GaN-LED can be greatly improved.
Źródło:
Optica Applicata; 2021, 51, 4; 529-540
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly accurate calibration system for electronic instrument transformers
Autorzy:
Tong, Y.
Ye, G.
Guo, K.
Li, H.
Powiązania:
https://bibliotekanauki.pl/articles/220441.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electronic instrument transformers
digital output
calibration system
virtual instrument
Fourthorder Convolution Window
Opis:
A high accurate electronic instrument transformer calibration system is introduced in this paper. The system uses the fourth-order convolution window algorithm for the error calculation method. Compared with Fast Fourier Transform, which is recommended by standard IEC-60044-8 (Electronic current transformers), it has higher accuracy. The relative measuring errors caused by asynchronous sampling could be reduced effectively without any special hardware technique adopted. The results show that the ratio error caused by asynchronous sampling can be reduced to 10-4, and the phase error can be reduced to 10-3 degrees when the deviation of frequency is within š0.5 Hz. The present method of measurement processing is achieved by a high-accuracy USB multifunction data acquisition (DAQ) card and virtual measurement devices, with low cost, short exploitation period and high stability.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 315-322
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of fuel combustion and emission characteristics of marine diesel engines using advanced fuels
Autorzy:
Changxiong, Li
Hu, Yihuai
Yang, Zy
Guo, Hao
Powiązania:
https://bibliotekanauki.pl/articles/34615637.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine diesel engine
PODE
combustion characteristics
emission performance
Opis:
In order to explore the potential application of oxygenated fuels, polyoxymethylene dimethyl ethers (PODE), as an alternative fuel for marine diesel engines, the fuel combustion performance and gas emission characteristics of pure diesel oil, diesel-blended PODE, and pure PODE were tested on a marine diesel engine under different running conditions. The experimental results indicate that oxygen consumption can be reduced by diesel-blended PODE and pure PODE. The in-cylinder pressure and exothermic curve were consistent with the trend of diesel oil. Also, the ignition delay of diesel-blended PODE and pure PODE decreased, and the diffusion rate was accelerated, which helped to improve the combustion performance of diesel engines. Diesel blended PODE and pure PODE reduced the particulate matter (PM) emissions by up to 56.9% and 86.8%, respectively, and CO emissions by up to 51.1% and 56.3%, respectively. NOx emissions were gradually decreased with engine load. CO2 emissions were slightly increased, and the effective fuel consumption was increased up to 48% and 132%, respectively. It was shown that PODE could provide comparable power in a marine diesel engine and improve the fuel combustion and gas emission of the engine as a clean alternative fuel for marine diesel engines.
Źródło:
Polish Maritime Research; 2023, 3; 48-58
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-principles calculations of electronic structure of rhodochrosite with impurity
Autorzy:
He, Guichun
Li, Kun
Guo, Tengbo
Li, Shaoping
Huang, Chaojun
Zeng, Qinghua
Powiązania:
https://bibliotekanauki.pl/articles/1449610.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rhodochrosite
first principles calculations
electronic structure
density of states
Opis:
The electronic structure of rhodochrosite containing impurity defects is studied by using the first principles density functional theory. The energy band structure, density of states and electronic distribution are calculated for rhodochrosite crystal models with various impurities (e.g., Cu, Ca, Mg, Zn, Fe). This paper discusses the effects of such defects on the electronic structure of rhodochrosite. The calculation results show that the impurity defects have a great impact on the surface electrical properties of rhodochrosite. For example, Ca and Mg impurities reduce the semiconductor width of rhodochrosite. Both Ca and Mg atoms in orbital bonding act as electron donors in which Ca3p and Mg2p orbits provide electrons while O2p orbits receive electrons. Moreover, the more number of valence electrons of Mn is the weaker covalent interaction between Mn and O atoms will be. Meanwhile, decrease of the total energy of rhodochrosite, makes the structure more stable. When Fe, Zn and Cu impurities are contained, the forbidden gap becomes narrower, which improves the conductivity of rhodochrosite. In addition, impurity bands will be formed in the 3d orbits of rhodochrosite as shown in its density of states, and the number of electrons in 3d orbits will increase. This weakens the covalence of O atoms, decreases the population values of O-Mn, increases the bond length, and enhances the ionicity of O-Mn bonds. The impurity of all defects considered in this study have shown an improved conductivity of rhodochrosite, and increased hole concentration of Mn atoms, which will be of great benefit to the adsorption of anionic collectors and enhance the electrochemical properties for rhodochrosite flotation process.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 195-203
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
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:
A flotation combined extraction process for improving the whiteness of phosphogypsum
Autorzy:
Li, Jiangli
Guo, Yongjie
Fan, Peiqiang
Li, Haibin
Chen, Ciyun
Xu, Shuai
Du, Lingpan
Powiązania:
https://bibliotekanauki.pl/articles/24085918.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
phosphogypsum
whiteness
desilication
high-value utilization
floatation
extraction
Opis:
Every year, the production of industrial phosphoric acid generates more than 100 Tg of phosphogypsum (PG), leading to significant environmental damage and the occupation of a vast amount of land space. The urgent need to explore applications for PG has become increasingly apparent. However, impurities such as organic substances, slime, phosphorite, and SiO2 reduce the whiteness of PG, making it difficult to utilize for high-value applications. To address this issue, this study employed a two-stage flotation process to remove the majority of impurities, including SiO2, organic substances, and fine slime adhered to the surface of PG particles. The raw PG sample was first sieved to remove some SiO2 particles. After flotation, sulfuric acid and tributyl phosphate were introduced to decompose the PG particles and remove the impurities wrapped inside. Following this flotation combined extraction process, the whiteness of the PG sample improved from 54.1% to 92.9%, meeting the requirements for building walls and filters.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 3; art. no. 170043
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity enhancement of a wavelength interrogation-based optical fiber surface plasmon resonance sensor for hemoglobin concentration using barium titanate
Autorzy:
Shi, Zhen-Jiang
Guo, Shi-Liang
Li, Xin
Li, Zhi-Quan
Meng, Shu-Han
Li, Chong-Zhen
Powiązania:
https://bibliotekanauki.pl/articles/27310091.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
surface plasmon resonance
wavelength interrogation
barium titanate
sensitivity enhancement
hemoglobin concentration
Opis:
In this paper, the performances of a wavelength interrogation-based optical fiber surface plasmon resonance sensor for hemoglobin (Hb) concentration is investigated by theoretical simulation. The proposed configuration incorporates optical fiber, 70 nm silver, 18 nm barium titanate (BaTiO3), and 2 nm zinc oxide. Simulation results show the sensor exhibits refractive index sensitivity of 4023 nm/RIU and concentration sensitivity of 10.0873 nm/(g∙dL), along with Hb concentration varying from 0 to 14 g/dL. This paper especially focuses on the influence of BaTiO3 on the performances of the proposed sensor with light wavelength ranging from 350 to 1000 nm. Comparison analysis indicates sandwiching 18 nm BaTiO3 between sensing layers not only enhances the concentration sensitivity by 30.14% but also decreases the nonlinear error of the sensor from 0.68% to 0.63%. For a wavelength accuracy of 0.1 nm, the proposed sensor can provide a resolution of 0.0099 g/dL for Hb concentration detection.
Źródło:
Optica Applicata; 2023, 53, 2; 167--184
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear degradation modeling and maintenance policy for a two-stage degradation system based on cumulative damage model
System charakteryzujący się dwuetapowym procesem degradacji: nieliniowe modelowanie degradacji oraz wyznaczanie strategii eksploatacji systemu na podstawie modelu sumowania uszkodzeń
Autorzy:
Ni, X.
Zhao, J.
Song, W.
Guo, C.
Li, H.
Powiązania:
https://bibliotekanauki.pl/articles/301523.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
two-stage
nonlinear
degradation modeling
cumulative damage model
maintenance policy
dwu-etapowy
nieliniowy
modelowanie degradacji
model sumowania uszkodzeń
strategia eksploatacji
Opis:
This paper attempts to take into account a two-stage degradation system which degradation rate is non-stationary and change over time. The system degradation is thought to be caused by shocks, and system degradation model is established based on cumulative damage model. The nonlinear degradation process is expressed by different shock damage and shock counting. And shock damage and shock counting are assumed to be Gamma distribution and non-homogeneous Poisson process, respectively. On the basis of these, system reliability model and nonlinear degradation model are given. In order to optimal maintenance policy for considered system, adaptive maintenance policy and time-dependent maintenance policy are studied, and mean maintenance cost rate is established to evaluate the maintenance policies. Numerical examples are given to analyze the influences of degradation model parameters and find optimal maintenance policy for considered system.
W przedstawionym artykule badano system, w którym proces degradacji zachodzi dwuetapowo, a szybkość degradacji jest zmienna w czasie. Przyjęto, że do degradacji systemu dochodzi w wyniku wstrząsów. Model degradacji systemu oparto na modelu sumowania uszkodzeń. Nieliniowy proces degradacji określono jako taki, w którym uszkodzenie powodowane wstrząsem oraz częstotliwość wstrząsów są wartościami zmiennymi. Przyjęto, że uszkodzenie powodowane wstrząsem ma rozkład gamma a częstotliwość wstrząsów jest niejednorodnym procesem Poissona. Na tej podstawie utworzono model niezawodności systemu oraz model degradacji nieliniowej. W celu opracowania optymalnej strategii eksploatacji dla rozpatrywanego systemu, rozważono dwa typy strategii utrzymania ruchu: strategię adaptacyjną oraz strategię czasowo-zależną. Strategie te oceniano określając średni poziom kosztów eksploatacji. Przykłady numeryczne posłużyły do analizy wpływu parametrów modelu degradacji oraz pozwoliły określić optymalną strategię utrzymania dla rozpatrywanego systemu.
Źródło:
Eksploatacja i Niezawodność; 2016, 18, 2; 171-180
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression and characterisation of cucumber fruit flesh thickness-related gene CSA2M058670.1
Autorzy:
Wang, W.
Wang, S.
Guo, Y.
Li, M.
Hou, L.
Powiązania:
https://bibliotekanauki.pl/articles/12709293.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
Bulked segregant analysis combined with specific length amplified fragment sequencing techniques have been applied to determine the fine genetic mapping of fruit flesh thickness-related genes in cucumber. Herein, the Csa2M058670.1 gene was subjected to real time fluorescence quantitative PCR (qRT-PCR) and sequence analysis, indicating a strong correlation with cucumber fruit flesh thickness. Expression and characterisation of the Csa2M058670.1 gene were performed based on previous studies. The results of the fluorescence-based quantitative PCR showed that Csa2M058670.1 was expressed in all organs, but levels were highest in fruit peel, fruit flesh, and female flowers. Furthermore, Csa2M058670.1 expression was induced by abiotic stresses including drought, low temperature, and high salt. Domain analysis revealed that the protein encoded by Csa2M058670.1 possesses an SET (Su(var), Enhancern of zeste CE(z), and Trithorax) domain that may control cell division and differentiation. Therefore, we speculated that Csa2M058670.1 might affect fruit flesh thickness in cucumbers by influencing cell division.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 2; 25-33
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time requirements in closed and open batch distillation arrangements for separation of a binary mixture
Autorzy:
Zhao, Shuo
Bai, Peng
Guo, Xianghai
Tang, Ke
Li, Guangzhong
Powiązania:
https://bibliotekanauki.pl/articles/778400.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
time requirements
closed operation
multivessel column
binary mixture
Opis:
Batch time requirements are provided for the separation of binary zeotropic mixtures in two different multivessel columns (with and without vapor bypass), a non-cyclic two-vessel column and a regular batch column based on dynamic simulations. The first three columns are operated as closed (total reflux) systems and the regular batch column is operated as an open (partial reflux) system. We analyze the effects of feed composition, relative volatility and product specification on the time requirements. The multivessel arrangements perform better than the regular batch column, which requires from 4.00 to 34.67% more time to complete a given separation. The elimination of the vapor bypass in the multivessel column is impractical though it has a positive effect on the batch time requirements. Thus, the multivessel column, with the vapor stream bypassing the intermediate vessel, is proposed as the best candidate for a binary zeotropic mixture with low concentration of light component, low relative volatility and high product purity demand. Furthermore, an experimental multivessel column with vapor bypass is built and the corresponding experiments verify the simulations.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 4; 66-74
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic-accumulative operation policy of continuous distillation for the purification of anisole
Autorzy:
Wang, Z.
Li, S.
Wang, C.
Guo, X.
Bai, P.
Powiązania:
https://bibliotekanauki.pl/articles/779622.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
anisole recycling
dynamic-accumulative operation policy
continuous distillation
simulation
Opis:
In the B10 isotope enrichment industry, the purification of anisole mixture makes great sense. A dynamic-accumulative operation policy of continuous distillation (DACD) with repeated filling and dumping of the still is proposed for the separation of trace heavy impurities in the recycled anisole. To simulate and optimize the purification process of anisole, a mathematical model of DACD is derived, and the computer codes are developed in the MATLAB environment. Moreover, the experiment is performed in a pilot-scale distillation column. The results show that the experimental date agrees well with simulation results. DACD could solve the difficulty of flow rate control when the bottom flow rate is very small in continuous distillation. The size of the still in this operation mode is also smaller than that in batch distillation. And the yield of anisole is raised to 99.91%. In a word, DACD is especially suitable for separating trace heavy impurities from the recycled anisole.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 1; 33-39
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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