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Review of terahertz semiconductor sources

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Journal of Semiconductors 2012年第3期33卷 1-4页

作者：冯伟 Department of Physics Jiangsu University

Terahertz（THz） technology can be used in information science,biology,medicine,astronomy,and environmental *** sources are the key devices in THz *** author gives a brief review of THz semiconductor sources,such as GaAs_（1-x）N_x Gunn-like diodes,quantum wells（QWs） negative-effective-mass （NEM） THz oscillators,and the THz quantum cascade lasers（QCLs）.THz current self-oscillation in doped GaAs_（1-x）N_x diodes driven by a DC electric field was *** current self-oscillation is associated with the negative differential velocity effect in the highly nonparabolic conduction band of this unique material system. The current self-oscillations and spatiotemporal current patterns in QW NEM p~＋pp~＋ diodes was studied by considering scattering contributions from impurities,acoustic phonons,and optic *** is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-oscillating *** NEM p~＋pp~＋ diode may be used as an electrically tunable THz ***,by using the Monte Carlo method, the device parameters of resonant-phonon THz QCLs were *** results show that the calculated gain is more sensitive to the injection barrier width,the doping concentration,and the phonon extraction level separation, which is consistent with the experiments.

关键词： THz semiconductor sources GaAs_(1-x)N_x Gunn-like diode negative-effective-mass THz oscillator THz quantum cascade laser

Nonlinear dynamics in wurtzite InN diodes under terahertz radiation

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Chinese Physics B 2012年第3期21卷 411-415页

作者：冯伟 Department of Physics Jiangsu University

We carry out a theoretical study of nonlinear dynamics in terahertz-driven n＋nn＋ wurtzite InN diodes by using time-dependent drift diffusion equations. A cooperative nonlinear oscillatory mode appears due to the negative differential mobility effect, which is the unique feature of wurtzite InN aroused by its strong nonparabolicity of the I＂1 valley. The appearance of different nonlinear oscillatory modes, including periodic and chaotic states, is attributed to the competition between the self-sustained oscillation and the external driving oscillation. The transitions between the periodic and chaotic states are carefully investigated using chaos-detecting methods, such as the bifurcation diagram, the Fourier spectrum and the first return map. The resulting bifurcation diagram displays an interesting and complex transition picture with the driving amplitude as the control parameter.

关键词： nonlinear dynamics terahertz radiation wurtzite InN

Microstructure and texture evolution during recrystallization of low-carbon steel sheets

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Journal of Iron and Steel Research International 2017年第1期24卷 84-90页

作者： Dong-dong Zhuang Lei-gang Wang Yao Huang Xiao-min Li Hua-yang Zhang De-wei Ren School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina School of Material Science and Engineering Shandong UniversityJinan 250061ShandongChina Metallurgical Corporation of China Group Shanghai 201900China

Aluminum killed low-carbon steel sheets were cold rolled at different reduction ratios and annealed using different temperatures and holding *** Vickers hardness was *** results show that when cold rolling reduction ratios increase from 40% to 81%,recrystallization temperatures decrease from 602℃ to 572℃ during 4hisochronal annealing,as well recrystallization holding time decreases from 117 min to 5min during isothermal annealing at 610℃.All recrystallization temperatures and holding time can be calculated using the annealing experiment *** was examined through electron backscattered diffraction（EBSD）.The results show that as rolling direction preferentially grows,equiaxed grains grow into cake-type during ***-type grains are more beneficial to obtaining ideal〈111〉//ND（normal direcrtion）orientation texture.{111}orientation grains nucleate and grow up *** grains of{111}〈110〉orientations grow into new recrystallization grains of{111}〈123〉and{111}〈112〉during *** formation can be explained by directional nucleation.

关键词： Aluminum killed low-carbon steel sheet Recrystallization Annealing Vickers hardness Texture

Numerical simulation of effect of bionic V-riblet non-smooth surface on tire anti-hydroplaning

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Journal of Central South university 2015年第10期22卷 3900-3908页

作者：周海超王国林杨建薛开鑫 School of Automotive and Traffic Engineering Jiangsu University

Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydroplaning performance was investigated by using computational fluid dynamics(CFD). The physical model of the object(model of V-riblet surface distribution, hydroplaning model) and SST k-ω turbulence model were established for numerical analysis of tire hydroplaning. With the help of a orthogonal table L16(45), the parameters of V-riblet structure design compared to the smooth structure were analyzed, and obtained the priority level of the experimental factors as well as the best combination within the scope of the experiment. The simulation results show that V-riblet structure can reduce water flow resistance by disturbing the eddy movement in boundary layers. Then, the preferred type of V-riblet non-smooth structure was arranged on the bottom of tire grooves for hydroplaning performance analysis. The results show that bionic V-riblet non-smooth structure can effectively increase hydroplaning velocity and improve tire anti-hydroplaning performance. Bionic design of tire tread pattern grooves is a good way to promote anti-hydroplaning performance without increasing additional groove space, so that tire grip performance and roll noise are avoided due to grooves space enlargement.

关键词： tire anti-hydroplaning bionic non-smooth surfaces(BNSS) numerical simulation

3-D Thermo-Stress Field in Laminated Cylindrical Shells

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Computer Modeling in Engineering & Sciences 2019年第10期121卷 215-247页

作者： Hai Qian Sai-Huen Lo Ding Zhou Yang Yang Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang212013China Department of Civil Engineering University of Hong KongHong KongChina College of Civil Engineering Nanjing Tech UniversityNanjing210009China.

The temperature and the stress distribution in simply-supported laminated cylindrical shells undergo thermal loads on the surface have been *** solutions of physical quantities including temperature,heat flux,thermal displacement and stress are developed for the cylindrical laminated *** shells are partitioned into more thin *** cylindrical coordinate,analytical expressions for physical quantities inside each layer are *** into account the compatibility of physical quantities at the interfaces,the relations between the outer and the inner layer of the laminated shell can be described with a transfer *** undetermined parameters from the solutions of each layer can be obtained with boundary *** convergence of the solutions to the number of Fourier series terms has been *** accuracy and feasibility of the present method is verified by comparing theoretical results with numerical outcomes due to Finite Element Method(FEM).Finally,the influences of surface temperature,geometrical size and material properties with respects to temperature,thermal stresses and displacement of layered cylindrical shell are worked out in details in a parameter study.

关键词： Laminated cylindrical shells thermo-elasticity analytical solutions transfer matrix

Bioinspired Activation of N_(2) on Asymmetrical Coordinated Fe Grafted 1T MoS_(2) at Room Temperature

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Chinese Journal of Chemistry 2021年第7期39卷 1898-1904页

作者： Jiaojiao Guo Maoyu Wang Liang Xu Xiaomin Li Asma Iqbal George ESterbinsky Hao Yang Miao Xie Jiantao Zai Zhenxing Feng Tao Cheng Xuefeng Qian School of Chemistry and Chemical Engineering and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai200240 China School of Chemical Biologicaland Environmental EngineeringOregon State UniversityCorvallisOR97331 USA Institute of Functional Nano and Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhouJiangsu215123 China advanced Photon Source Argonne National LaboratoryArgonneIL60431 USA Instrumental Analysis Center Shanghai Jiao Tong UniversityShanghai200240 China

Main observation and conclusion Inspired by the nitrogen fixation process on MoFe nitrogenase,asymmetrical coordinated Fe grafted onto 1T MoS_(2) were successfully *** unique electron-rich structure with asymmetrical coordination made the 1T Fe_(0.1)Mo_(0.9)S_(2) layered material actively react with water and dinitrogen at room temperature and atmosphere pressure.

关键词： Monolayers Redox chemistry Electron transfer Nitrogen fixation 1T MoS_(2)

Enriched electrophilic oxygen species facilitate acidic oxygen evolution on Ru-Mo binary oxide catalysts

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Nano Research 2024年第3期17卷 1165-1172页

作者： Yaya Wang Yunzhou Wen Yumeng Cheng Xinhong Chen Mengjiao Zhuansun Tongbao Wang Jun Li Debora Meira Huarui Sun Jun Wei Jia Zhou Yuhang Wang Sisi He Shenzhen Key Laboratory of Flexible Printed Electronics Technology Harbin Institute of Technology(Shenzhen)University TownShenzhen 518055China School of Science Harbin Institute of Technology(Shenzhen)University TownShenzhen 518055China Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory of Advanced Negative Carbon TechnologiesSoochow UniversitySuzhou 215123China Frontiers Science Center for Transformative Molecules Shanghai Jiao Tong UniversityShanghai 200240China Science Division Canadian Light SourceSaskatoonSKS7N 2V3Canada Photon Science Division Argonne National LaboratoryLemontIL60439USA School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)University TownShenzhen 518055China

The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly active,and durable electrocatalysts to replace Ir is a critical step in reducing the cost of green hydrogen *** we develop a Ru5Mo4Ox binary oxide catalyst that exhibits high activity and stability in acidic *** electron-withdrawing property of Mo enriches the electrophilic surface oxygen species,which promotes acidic OER to proceed via the adsorbate evolution *** a result,we achieve a 189 mV overpotential at 10 mA·cm^(-2) and a Tafel slope of 48.8 mV·dec^(-1).Our catalyst demonstrates a substantial 18-fold increase in intrinsic activity,as evaluated by turnover frequency,compared to commercially available RuO_(2) and IrO_(2) ***,we report a stable OER operation at 10 mA·cm^(-2) for 100 h with a low degradation rate of 2.05 mV·h^(-1).

关键词： electrocatalysis oxygen evolution reaction(OER) ruthenium(Ru)-based oxide molybdenum electrophilic oxygen