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Wyszukujesz frazę "Li, Kun" wg kryterium: Autor


Tytuł:
First-principles calculations of electronic structure of rhodochrosite with impurity
Autorzy:
He, Guichun
Li, Kun
Guo, Tengbo
Li, Shaoping
Huang, Chaojun
Zeng, Qinghua
Tematy:
rhodochrosite
first principles calculations
electronic structure
density of states
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/1449610.pdf  Link otwiera się w nowym oknie
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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of a water hammer and cavitation on vibration transients in a reservoir-pipe-valve system
Autorzy:
Miao, Yang
Qiu, Zaihui
Zhang, Xiaolu
Jiang, Yuncheng
Pan, Jun
Liu, Yi
Zhang, Li
Li, Kun
Tematy:
reservoir-pipe-valve system (RPV system)
water hammer
vibration
cavitation
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/2055065.pdf  Link otwiera się w nowym oknie
Opis:
An extraordinary phenomenon with violent oscillation, accompanied by an abnormal “click” sound is observed during the valve closing in a fuel feeding pipe system. A fluctuation model with flow cavitation, in which time-varying stiffness, time-varying damping coefficients and flow cavitation are comprehensively considered, is proposed. On this basis, a dynamic vibration equation is established and an expression of flow pressure at the valve port is derived. The critical displacement of the flow cavitation system is defined. When the vibration amplitude reaches the critical displacement, cavitation occurs. Based on this model, simulation of vibration displacement and flow pressure is given. The simulated transient process shows the phenomena of vibration fluctuation with cavitation. The results are compared with the experimental data measured by a pressure sensor. Under our experimental conditions, the critical displacement of vibration is 1.41mm, and the average relative pressure peak error is 0.022. The comparison between the simulation and experimental results shows that they are in an acceptable agreement.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration transients of reservoir-pipe-valve system caused by water hammer
Autorzy:
Miao, Yang
Jiang, Yuncheng
Qiu, Zaihui
Pan, Jun
Wang, Lu
Han, Zhenrong
Li, Kun
Zhang, Li
Zhang, Xiaolu
Tematy:
reservoir-pipe-valve system (RPV system)
water hammer
vibration
transients
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/1839616.pdf  Link otwiera się w nowym oknie
Opis:
A severe oscillation, accompanied with an abnormal “click” sound, of a fuel feeding pipe system during valve closing, when the feeding flowrate reaches a certain value, is observed experimentally. A fluctuation model in which stiffness and damping coefficients of the vibration system are time varying is proposed. Each coefficient is composed of two parts, one of which is constant and the other is time varying. Based on this model, simulation transients of the vibration displacement, velocity and pressure in the pipe are presented. Simulations of the pressure transients are compared with experimental data detected by pressure transducer, which shows that both have fluctuations in the transient process at a large flowrate.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manoeuvring prediction of KVLCC2 with hydrodynamic derivatives generated by a virtual captive model test
Autorzy:
Dai, Kun
Li, Yunbo
Tematy:
MMG model
KVLCC2
CFD
manoeuvring prediction
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Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/258850.pdf  Link otwiera się w nowym oknie
Opis:
This paper describes the application of computational fluid dynamics rather than a towing tank test for the prediction of hydrodynamic derivatives using a RANS-based solver. Virtual captive model tests are conducted, including an oblique towing test and circular motion test for a bare model scale KVLCC2 hull, to obtain linear and nonlinear hydrodynamic derivatives in the 3rd-order MMG model. A static drift test is used in a convergence study to verify the numerical accuracy. The computed hydrodynamic forces and derivatives are compared with the available captive model test data, showing good agreement overall. Simulations of standard turning and zigzag manoeuvres are carried out with the computed hydrodynamic derivatives and are compared with available experimental data. The results show an acceptable level of prediction accuracy, indicating that the proposed method is capable of predicting manoeuvring motions.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pelvis and thoracolumbar spine response in simulated under-body blast impacts and protective seat cushion design
Autorzy:
Luo, Wei
Niu, Kun
Mo, Fuhao
Li, Guibing
Tematy:
under-body blast
thoracolumbar spine
biomechanical modelling
protective cushion
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/55622226.pdf  Link otwiera się w nowym oknie
Opis:
The aim of this study is to investigate the dynamic and biomechanical response of the pelvis and thoracolumbar spine in simulated under-body blast (UBB) impacts and design of protective seat cushion for thoracolumbar spine injuries. Methods: A wholebody FE (finite element) human body model in the anthropometry of Chinese 50th% adult male (named as C-HBM) was validated against existing PHMS (Postmortem Human Subjects) test data and employed to understand the dynamic and biomechanical response of the pelvis and thoracolumbar spine from FE simulations of UBB impacts. Then, the protective capability of different seat cushion designs for UBB pelvis and thoracolumbar injury risk was compared based on the predictions of the C-HBM. Results: The predicted spinal accelerations from the C-HUM are almost within the PHMS corridors. UBB impact combined with the effects from physiological curve of the human thoracolumbar spine and torso inertia leads to thoracolumbar spine anterior bending and axial compression, which results in stress concentration in the segments of T4–T8, T12–L1 and L4–L5. Foam seat cushion can effectively reduce the risk of thoracolumbar spine injury of armored vehicle occupants in UBB impacts, and the DO3 foam has better protective performance than ordinary foam, the 60 mm thick DO3 foam could reduce pelvic acceleration peak and DRIz value by 52.8% and 17.2%, respectively. Conclusions: UBB spinal injury risk is sensitive to the input load level, but reducing the pelvic acceleration peak only is not enough for protection of spinal UBB injury risk, control of torso inertia effect would be much helpful.
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
Tematy:
light-emitting diode
surface plasmon
grating
quantum well
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/2033893.pdf  Link otwiera się w nowym oknie
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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of a nonlinear tuned mass damper by using the multi-scale method
Autorzy:
Liu, Junfeng
Yao, Ji
Huang, Kun
Zhang, Qing
Ze, Li
Tematy:
nonlinear characteristics
complex average method
multi-scale method
nonlinear design
control performance
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/2104766.pdf  Link otwiera się w nowym oknie
Opis:
A tuned mass damper is a kind of vibration damping device which has been widely used in tall buildings, machinery, bridges, aerospace engineering and other fields. In practical engineering applications, due to large deformation caused by large displacement, errors in engineering constructions and the existence of limit devices, the structure and tuned mass dampers inevitably produce some nonlinear characteristics, but these nonlinearities are often ignored. The results of this study confirm that the nonlinearity of the structure and the mass damper should be considered in the process of optimal frequency design, otherwise there will be a large deviation between the design optimal frequency of the mass damper and the actual optimal frequency. In this paper, nonlinear characteristics of the tuned mass damper and the main structure are considered. The first-order differential equations are obtained by using the complex average method, and the nonlinear equations of the tuned mass damper system are derived by using the multi-scale method. On this basis, the parameters are determined. The numerical results show that the error of the approximate solution method is small in the given example. The nonlinear tuned mass damper with nonlinear design exhibits a better control performance.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Impacts of Crustacean Zooplankton on a Natural Ciliate Community: a Short-term Incubation Experiment
Autorzy:
Li, Jing
Yang, Kun
Chen, Feizhou
Lu, Wenxuan
Fang, Ting
Zhao, Xiuxia
Li, Haiyang
Cui, Kai
Tematy:
ciliates
small-bodied cladocerans
pseudodiaptomid copepods
suppression impacts
functional groups
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Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Powiązania:
https://bibliotekanauki.pl/articles/52401895.pdf  Link otwiera się w nowym oknie
Opis:
Direct and indirect effects of crustacean zooplankton (cladocerans and copepods) are important regulators of ciliate communities, especially in eutrophic systems. However, it is not clear whether pseudodiaptomids (e.g., Schmackeria), one of the dominant calanoid copepods in Chinese lakes, effectively impacts natural ciliate communities. The impacts of small-bodied cladocerans (e.g., Bosmina) on ciliates are also controversial. We performed an incubation experiment using winter lake water from Lake Chaohu to assess the structuring effects that crustacean zooplankton have on natural ciliate populations. The presence and absence of cladocerans (Bosmina sp.) and copepods (Schmackeria inopinus) were alternated in four treatments. Both Bosmina sp. and Schmackeria inopinus had substantial impacts on ciliate abundance, biomass, and community structure. The response of ciliates was different in the presence of Bosmina sp. compared with Schmackeria inopinus and varied among categories such as the ciliate population, relative body size and functional feeding group. Our results also highlight the importance of interference and exploitative competition among metazooplankton groups.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Permeability of N, P, K-fertilizer nutrient and water vapor through PLA, PLA/PS, and PLA/HA membranes
Autorzy:
Deng, Xiaonan
Ye, Sihong
Liu, Kun
Li, Changfeng
Liu, Fangzhi
Yan, Xiaoming
Tematy:
Permeability
polymer-coated fertilizer
mathematical model
poly lactic acid
membrane
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Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:
https://bibliotekanauki.pl/articles/777994.pdf  Link otwiera się w nowym oknie
Opis:
To collect permeability data and establish its database of fertilizer nutrients and water vapor through different polymer membranes for the development of polymer-coated fertilizer, the permeabilities of N-, P-, and K-nutrient from saturated aqueous of urea, NaH2PO4 and KCl solution and the permeability of water vapor through the membranes of poly lactic acid (PLA), its blends with polystyrene (PS), and its composites with humic acid (HA) particles were determined experimentally at the temperatures of 288, 298, and 308 K, respectively. The effects of the addition of PS and HA particles, temperature, and coating thickness on the permeability of fertilizer nutrient and water vapor were investigated. It was found that the addition of PS and HA increased the permeability for both the fertilizer nutrients and water vapor. The increase in temperature raised the permeability of N-, P-, and K-nutrient while decrease the permeability of water vapor in the range studied.
Dostawca treści:
Biblioteka Nauki
Artykuł

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