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Preparation of Ligand Free Au NPs/PPV Composites with High Stability and Photo-electric Response

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Chinese Journal of Polymer Science 2015年第2期33卷 215-223页

作者： Fei Zhai Hao-tong Wei Su-mei Zhan Gan Jin Bai Yang 孙海珠黄宗浩 College of Chemistry Northeast Normal University state Key Laboratory of Supramolecular Structure & Materials College of Chemistry Jilin University

A novel kind of ligand free aurum nanoparticles（Au NPs）/poly（p-phenylene-vinylene）（PPV） composites was prepared via a simple approach. Although there were no ligands coating on the surface of the Au NPs, the Au NPs/PPV precursor composite exhibited excellent stability that no obvious variance was found as long as 6 months at -4 ℃ in aqueous and alcohol mixed solutions. This was attributed to the strong interaction between Au NPs and PPV precursor, which was further strengthened after heat transformation. Fourier transform infrared（FTIR） and Raman spectra showed the interaction between benzene ring in PPV and Au NPs led to the part transformation of the sp2 hybrid orbital into the sp3 one during the composite formation. As a result, the photoluminescence（PL） life time of PPV in the composite was longer than that of pure PPV. The Au NPs/PPV composite exhibited good photo-electric response, indicating their potential application in the area of the photoelectric conversion devices.

关键词： Au Nanoparticle PPV Composite Photo-electric

High temperature electrochemical discharge performance of LaFeO3 coated with C/Ni as anode material for NiMH batteries

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Progress in Natural Science:Materials International 2022年第6期32卷 684-692页

作者： Kailiang Ren Jiajia Miao Wenzhuo Shen Huanhuan Su Yunpeng Pan Jiajin Zhao Xiangyu Pan Yuan Li Yaokun Fu Lu Zhang Shumin Han state Key Laboratory of Metastable Materials Science and Technology Yanshan University School of Environmental and Chemical Engineering Yanshan University

Perovskite LaFeO3is considered as a promising new anode material for nickel/metal hydride batteries due to its low cost,environmental friendliness and high temperature ***,the poor conductivity of LaFeO3material restricts the discharge ability,which is problematic for its future widespread *** solve the above issue,in this study,we prepared C/Ni-coated LaFeO3composite in view of the excellent electrical conductivity of carbon and nickel *** show that the C/Ni-coated LaFeO3composite delivers remarkably increased discharge capacity of ～345 mAh g-1at 60℃ in contrast to ～267 mAh g-1for pure ***,the carbon and nickel not only increase the electrical conductivity of the LaFeO3but also reduces the agglomeration of the LaFeO3,therefore,the C/Ni-coated LaFeO3composite serves superior long cycle-life,which maintains 60.9% after 100 cycles(52.9% for the LaFeO3sample).In overall,the electrochemical behavior of the C/Ni-coated LaFeO3composite confirms its high potential as nickel/metal hydride batteries for energy storage applications.

关键词： Energy storage Perovskite-type oxide Nickel metal hydride batteries LaFeO 3 Electrochemical performance

Performance Analysis of Spatial Modulation Aided UAV Communication Systems in Cooperative Relay Networks

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Chinese Journal of Electronics 2024年第6期33卷 1492-1503页

作者： Xiangbin YU Mingfeng XIE Ning LI Cuimin PAN College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics state Key Laboratory of Millimeter Waves Southeast University

In this paper, by introducing the spatial modulation(SM) scheme into the unmanned aerial vehicle(UAV) relaying system, an SM-aided UAV(SM-UAV) cooperative relay network is presented. The performance of the SM-UAV relay network is investigated over Nakagami-m fading channels, where the UAV remains stationary over a given area. According to the performance analysis, using the amplify-and-forward(AF) protocol, the effective signal-to-noise ratio(SNR) and the corresponding probability density function and moment generating function are,respectively, derived. With these results, the average bit error rate(BER) is further deduced, and resultant approximate closed-form expression is achieved. Based on the approximate BER, we derive the asymptotic BER to characterize the error performance of the system at high SNR. With this asymptotic BER, the diversity gain of the system is derived, and the resulting diversity order is attained. Simulation results illustrate the effectiveness of the performance analysis. Namely, approximate BER has the value close to the simulated one, and asymptotic BER can match the corresponding simulation well at high SNR. Thus, the BER performance of the system can be effectively assessed in theory, and conventional simulation will be avoided. Besides, the impacts of the antenna number, modulation order,fading parameter, and UAV position on the system performance are also analyzed. The results indicate that the BER performance is increased with the increases of Nakagami parameter m and/or receive antenna and/or the decrease of modulation order.

关键词： Fading channels System performance Bit error rate Modulation Receiving antennas Relay networks Diversity methods Autonomous aerial vehicles Performance analysis Signal to noise ratio

Review of magnetocaloric effect in perovskite-type oxides

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Chinese Physics B 2013年第5期22卷 24-34页

作者：钟伟区泽棠都有为 National Laboratory of Solid state Microstructures and School of Physics Nanjing University Chemistry Department Hong Kong Baptist University

We survey the magnetocaloric effect in perovskite-type oxides （including doped ABO3-type manganese oxides, A3B2OT-type two-layered perovskite oxides, and A2B＇B＇＇O6-type ordered double-perovskite oxides）. Magnetic entropy changes larger than those of gadolinium can be observed in polycrystalline La1-xCaxMnO3 and alkali-metal （Na or K） doped La0.8Ca0.2MnO3 perovskite-type manganese oxides. The large magnetic entropy change produced by an abrupt reduction of magnetization is attributed to the anomalous thermal expansion at the Curie temperature. Considerable mag- netic entropy changes can also be observed in two-layered perovskites Lal.6Cal.4Mn207 and La2.5-xK0.5＋xMn2O7＋6 （0 〈 x 〈 0.5）, and double-perovskite Ba2Fe1＋xMol-xO6 （0 〈 x 〈 0.3） near their respective Curie temperatures. Com- pared with rare earth metals and their alloys, the perovskite-type oxides are lower in cost, and they exhibit higher chemical stability and higher electrical resistivity, which together favor lower eddy-current heating. They are potential magnetic refrigerants at high temperatures, especially near room temperature.

关键词： perovskite-type oxides magnetocaloric effect magnetic entropy change magnetic phase transi-tion

An Improved Coupling of Numerical and Physical Models for Simulating Wave Propagation

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China Ocean Engineering 2014年第1期28卷 1-16页

作者：阳志文柳淑学李金宣 state Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Department of Mechanical Engineering Technical University of Denmark

An improved coupling of numerical and physical models for simulating 2D wave propagation is developed in this paper. In the proposed model, an unstructured finite element model （FEM） based Boussinesq equations is applied for the numerical wave simulation, and a 2D piston-type wavemaker is used for the physical wave generation. An innovative scheme combining fourth-order Lagrange interpolation and Runge-Kutta scheme is described for solving the coupling equation. A Transfer function modulation method is presented to minimize the errors induced from the hydrodynamic invalidity of the coupling model and/or the mechanical capability of the wavemaker in area where nonlinearities or dispersion predominate. The overall performance and applicability of the coupling model has been experimentally validated by accounting for both regular and irregular waves and varying bathymetry. Experimental results show that the proposed numerical scheme and transfer function modulation method are efficient for the data transfer from the numerical model to the physical model up to a deterministic level.

关键词： coupling numerical model physical model wave propagation transfer function modulation

Electronic relaxation of deep bulk trap and interface state in ZnO ceramics

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Chinese Physics B 2011年第2期20卷 332-339页

作者：杨雁李盛涛丁璨成鹏飞 state Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University School of Science Xi'an Polytechnic University

This paper investigates the electronic relaxation of deep bulk trap and interface state in ZnO ceramics based on dielectric spectra measured in a wide range of temperature, frequency and bias, in addition to the steady state response. It discusses the nature of net current flowing over the barrier affected by interface state, and then obtains temperature-dependent barrier height by approximate calculation from steady I-V （current-voltage） characteristics. Additional conductance and capacitance arising from deep bulk trap relaxation are calculated based on the displacement of the cross point between deep bulk trap and Fermi level under small AC signal. From the resonances due to deep bulk trap relaxation on dielectric spectra, the activation energies are obtained as 0.22 eV and 0.35 eV, which are consistent with the electronic levels of the main defect interstitial Zn and vacancy oxygen in the depletion layer. Under moderate bias, another resonance due to interface relaxation is shown on the dielectric spectra. The DC-like conductance is also observed in high temperature region on dielectric spectra, and the activation energy is much smaller than the barrier height in steady state condition, which is attributed to the displacement current coming from the shallow bulk trap relaxation or other factors.

关键词： ZnO deep bulk trap interface state relaxation

Response of anaerobes to methyl fluoride,2-bromoethanesulfonate and hydrogen during acetate degradation

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Journal of Environmental Sciences 2013年第5期25卷 857-864页

作者： Liping Hao Fan L Lei Li Liming Shao Pinjing He state Key Laboratory of Pollution Control and Resource Reuse Tongji University Institute of Waste Treatment and Reclamation Tongji University

To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradation of acetate,to the addition of methyl fluoride（CH3F）,2-bromoethanesulfonate（BES）and hydrogen were investigated in a thermophilic batch *** the methanogenic inhibitors,i.e.,CH3F and BES,showed their effectiveness on inhibiting CH4 production,whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES,as reflected by the fluctuated acetate *** acetate oxidation was thermodynamically blocked by hydrogen（H2）,while H2-utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly *** of PCR-DGGE fingerprinting showed that,CH3F did not influence the microbial populations ***,the BES and hydrogen notably altered the bacterial community structures and increased the *** gradually changed the methanogenic community structure by affecting the existence of different populations to different levels,whilst H2 greatly changed the abundance of different methanogenic populations,and induced growth of new species.

关键词： methanogenic inhibitor hydrogen thermophilic anaerobic digestion microbial diversity denaturing gradient gel electrophoresis(DGGE)

Ablation mechanism of TaC coating fabricated by chemical vapor deposition on carbon-carbon composites

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中国有色金属学会会刊：英文版 2009年第S3期19卷 689-695页

作者：李国栋熊翔黄可龙 state Key Laboratory of Powder Metallurgy Central South University School of Chemistry and Chemical Engineering Central South University

Ablation characteristics and mechanism at high temperature for TaC coatings on carbon-carbon composites were investigated by ablation experiments with low power laser and oxyacetylene flame. The results show that the TaC coating is decomposed at the initial stage of laser ablation in atmosphere, and free carbon diffused to the surface, then oxidized to the melt including carbon, oxygen and tantalum. With the increase of ablation time, the melt is oxidized to low valent tantalum-oxide and Ta2O5 is formed finally. During the melt cooling, needle-like crystals of Ta2O5 are precipitated. Between the melt and TaC coating, there exists a diffusion transition layer with thickness of 1-2 μm. The transition layer consists of fine crystals and pores including carbon, oxygen and tantalum. The oxyacetylene flame ablation at 2 300 ℃ results in the rapid oxidation of TaC and formation of protective liquid films of tantalum oxide on the coating surface, where the liquid film can fill up the cracks and cover the coating. In such case, the oxidation mechanism of TaC is converted to the oxygen solution and diffusion control mechanism.

关键词： TaC coating oxidation ablation mechanism carbon-carbon composites

Innovation Analysis Approach to Design Parameters of High Speed Train Carriage and Their Intrinsic Complexity Relationships

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1091-1100页

作者： Shou-Ne Xiao Ming-Meng Wang Guang-Zhong Hu Guang-Wu Yang state Key Laboratory of Traction Power Southwest Jiaotong University School of Mechanical Engineering Sichuan University of Science & Engineering

In view of the problem that it＇s difficult to accurately grasp the influence range and transmission path of the vehicle top design requirements on the underlying design parameters. Applying directed-weighted complex network to product parameter model is an important method that can clarify the relationships between product parameters and establish the top-down design of a product. The relationships of the product parameters of each node are calculated via a simple path searching algorithm, and the main design parameters are extracted by analysis and comparison. A uniform definition of the index formula for out-in degree can be provided based on the analysis of out- in-degree width and depth and control strength of train carriage body parameters. Vehicle gauge, axle load, crosswind and other parameters with higher values of the out-degree index are the most important boundary condi- tions; the most considerable performance indices are the parameters that have higher values of the out-in-degree index including torsional stiffness, maximum testing speed, service life of the vehicle, and so on; the main design parameters contain train carriage body weight, train weight per extended metre, train height and other parameters with higher values of the in-degree index. The network not only provides theoretical guidance for exploring the relationship of design parameters, but also further enriches the appli- cation of forward design method to high-speed trains.

关键词： Train carriage body parameters Complexnetwork Width influence Depth influence Parametercontrol strength