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Thermoelectric properties of Bi0.5Sb1.4-xNaxIn0.1Te3 alloys

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Rare Metals 2019年第12期38卷 1187-1192页

作者： Yue-zhen jiang Xing-Kai Duan School of Electronic Engineering Jiujiang UniversityJiujiang 332005China School of Mechanical and Materials Engineering Jiujiang UniversityJiujiang 332005China

The Bi(0.5)Sb(1.4-x)NaxIn(0.1)Te3(x=0.02-0.20)alloys were fabricated by high vacuum melting and hotpressing *** phase structures and morphology of the bulk samples were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM),*** of In and Na co-doping on the electrical and thermal transport properties were studied from room temperature to 500 *** coefficient of the Bi(0.5)Sb(1.5)Te3 can be enhanced by substituting Sb with In and Na at near room *** electrical conductivity of the In and Na co-doped samples is lower than that of the Bi(0.5)Sb(1.5)Te3 alloy from room temperature to 500 *** and Na co-doping of appropriate percentage optimizes the thermal conductivity of the Bi(0.5)Sb(1.5)Te3 *** minimum value of thermal conductivity of Bi(0.5)Sb(1.36)Na(0.04)In(0.1)Te3 alloy is 0.45 W·m^(-1) K^(-1) at 323 *** leads to a great improvement in the thermoelectric figure of merit(zT).The maximum zT value reaches 1.42 at 323 K.

关键词： Microstructure Co-doping Thermal conductivity Electrical properties

Component fault diagnosis for nonlinear systems

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Journal of Systems Engineering and Electronics 2016年第6期27卷 1283-1290页

作者： Junjie Huang zhen jiang Junwei Zhao School of Mechanical and Power Engineering Henan Polytechnic University School of Mechatronics Engineering and Automation Shanghai University

In the field of fault diagnosis, the state equation of nonlinear system, including the actuator and the component, has been established. When the faults in the system appear, it is difficult to observe the fault isolation between the actuator and the component. In order to diagnose the component fault in the nonlinear systems, a novel strategy is proposed. The nonlinear state equation with only the component system is built on mathematical equations. The nonlinearity of the component equation is expanded and estimated with Taylor series. If the actuator is perfect, the anomaly of the state equations reflects the component fault. The fault feature index is defined to detect the component fault and the initial fault. The numerical examples of the component faults are simulated for multiple-input multiple-output(MIMO)nonlinear systems. The results show that the component faults,as well as the incipient faults, can be detected. Furthermore, the effectiveness of the proposed strategy is verified. This method can also provide a foundation for the component fault reconfiguration control.

关键词： multiple-input multiple-output(MIMO) nonlinear systems component faults fault feature index fault diagnosis

Effects of Sequence Distribution and Physical Aging on Physical Properties of PES/PEES Random, Block, and Alternative Copolymers

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Chemical Research in Chinese Universities 2006年第6期22卷 787-791页

作者： ZHOU Xiao-ming jiang zhen-hua Alan G. MacDiarmid Lab College of Chemistry Jilin University Changchun 130012 P. R. China

The random, block, and alternative copolymers of poly ether sulfone（PES） and poly ether ether sulfone（PEES） were synthesized v/a three kinds of methods. The chemical structures of the three kinds of copolymers were characterized by ^13C NMR. Three kinds of PES/PEES copolymers（ Tg =215 ℃ ）, which were almost identical in composition but different in sequence distribution, were used. Their physical aging process was studied by differential scanning calorimetry（DSC） at three aging temperatures ranging between Tg -15 ℃ and Tg -25℃. The experimental results reveal that the alternative copolymer shows a lower enthalpy relaxation time 〈T〉 and apparent activation energy when compared with the random and block copolymers. The result of the electron-microscopy investigation of the three copolymers that were treated at 200 ℃ for 96 h indicates that the molecular aggregation of the copolymers changed from a randomly coiled amorphous phase to an ordered phase, and the ordered structure of the alternative copolymer was more distinct than that of the random phase. The experimental results of this study suggest that the motion of the sagments is affected by the different molecular-chain sequence distribution.

关键词： Physical aging Apparent activation energy Sequence distribution

Implicit high-order discontinuous Galerkin method with HWENO type limiters for steady viscous flow simulations

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Acta Mechanica Sinica 2013年第4期29卷 526-533页

作者： zhen-Hua jiang Chao Yan Jian Yu College of Aeronautics Science and Engineering Beijing University of Aeronautics and Astronautics

Two types of implicit algorithms have been im- proved for high order discontinuous Galerkin （DG） method to solve compressible Navier-Stokes （NS） equations on tri- angular grids. A block lower-upper symmetric Gauss- Seidel （BLU-SGS） approach is implemented as a nonlin- ear iterative scheme. And a modified LU-SGS （LLU-SGS） approach is suggested to reduce the memory requirements while retain the good convergence performance of the origi- nal LU-SGS approach. Both implicit schemes have the sig- nificant advantage that only the diagonal block matrix is stored. The resulting implicit high-order DG methods are applied, in combination with Hermite weighted essentially non-oscillatory （HWENO） limiters, to solve viscous flow problems. Numerical results demonstrate that the present implicit methods are able to achieve significant efficiency improvements over explicit counterparts and for viscous flows with shocks, and the HWENO limiters can be used to achieve the desired essentially non-oscillatory shock tran- sition and the designed high-order accuracy simultaneously.

关键词： Discontinuous Galerkin (DG) scheme ~ Implicitmethod ~ HWENO ~ High order ~ Unstructured grids

Aerodynamic Characteristics of Isolated Loaded Tires with Different Tread Patterns: Experiment and Simulation

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 107-122页

作者： Haichao Zhou zhen jiang Guolin Wang Shupei Zhang School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang 212013China

The current research of tire aerodynamics mainly focus on the isolated and simplified tread *** with the real complex pattern tire,the tread pattern structure and deformed profile of a loaded tire has a greatly influence on tire aerodynamic ***,the mechanisms of the isolated loaded tires with different tread patterns effects on the aerodynamic drag are subjects worthy of *** purpose of this study is to experimentally and compu-tationally investigate the aerodynamic characteristics of three tires 185/65 R14 with different patterns under loaded.A wind tunnel test model was first established using three-dimensional(3D)printing with a ratio of 1:1,and the pres-sure coefficients C_(p) of the three tires with different patterns are *** paper then conducted computational fluid dynamics(CFD)simulations for analyzing the pressure and flow *** accuracy of CFD simulation is verified by comparing the simulation results with the test results of pressure coefficients C_(p),and they are of good ***,the general analysis of pressure coefficients C_(p) results of the three tires indicates high-pressure area on the windward surface,and occurrence of low-pressure area on the leeward surface,the pressure coefficients C_(p) of all three tires decreased firstly and then increased along in the air flow *** authors finally analyzed the effect of tread patterns on the flow field around the tire and revealed the differences between flow characteristics and aerodynamic *** results show that,angle of tire lateral groove has great effect on the flow field characteristics such that;the more the angle of lateral groove agrees with the air flow direction,the less the flow separation and flow vortices,and a minimum observable aerodynamic *** research provides a guidance for the design of low aerodynamic drag tires,and helps to illustrate the impact of tire aerodynamics on the car body in the future.

关键词： Tire aerodynamic Wind tunnel test Numerical simulation Flow analysis

Morphology and Compatibility of Compatibilized Polyethersulfone and Polycarbonate Blends

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Chemical Research in Chinese Universities 2005年第5期21卷 611-614页

作者： SUN Xiao-bo jiang Dong WU Wei-chun jiang zhen-hua Research Center for Super Engineering Plastics of Ministry of Education College of Chemistry Jilin University Changchun 130021 P. R. China

A PES-PC （polyethersulfone-polycarbonate） multi block random copolymer was synthesized with two oligomers, polyethersulfone and polycarbonate. The effects of the copolymer, as a compatibilizer, on the morphology and compatibility of the PES-PC blends were investigated. It was found that the addition of this copolymer to the PES-PC blends could improve their compatibility.

关键词： Polyethersulfone Polycarbonate Blend Compatibilizer

A Novel Synthesis of Dimethyl Malonate by Carbonylation of Methyl Chloroacetate Catalyzed by Cobalt Complex

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Chinese Chemical Letters 2001年第3期12卷 207-210页

作者： Wei Hong SONG Xuan zhen jiang Department of Chemistry Zhejiang UniversityHangzhou 310027

A novel method of preparing dimethyl malonate by carbonylation of methyl chloroacetate catalyzed by Na[Co(CO)(4)] was proposed. Na[Co(CO)(4)] was synthesized in situ in the presence of Na2S2O3 and iron powder. The effects of some reaction parameters such as temperature. CO pressure and the concentrations of catalyst on the yields of dimethyl malonate were discussed. The kinetic data were studied and a possible reaction mechanism was proposed.

关键词： Dimethyl malonate cobalt complex carbonylation reaction mechanism

Novel Catalytic Hydrodechlorination of CCl_2F_2 over Supported PdCl_2-(n-C_4H_9)_4N^+Cl^- Molten salts

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Chinese Chemical Letters 2001年第6期12卷 533-536页

作者： Yu Cai CAO Xuan zhen jiang Department of Chemistry Zhejiang UniversityHangzhou 310027

A novel supported liquid phase film catalyst: Supported PdCl2-(n-C4H9),N+Cl- molten salts was found to be an effective catalyst with good stability for selective hydrodechlorination of CCl2F2 (CFC-12) to its alternatives CH2F2 and CHClF2. Addition of CoCl2, GaCl3 and CuCl2 to PdCl2-(n-C4H9),N+Cl- modifies the catalytic performance of supported molten salts.

关键词： Liquid film catalyst palladium chloride tetrabutylammonium chloride molten salts CFC-12 hydrodechlorination HFC-32 HCFC-22

K-Factors and Hamilton Cycles in Graphs

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Acta Mathematica Sinica,English Series 2007年第2期23卷 309-312页

作者： Zhi Guo WANG zhen jiang ZHAO College of Mathematics and Information Sciences He'nan University Kaifeng 475001 China P. O. Box 5122 No. 21 Beijin9 100094 China

We discuss k-factors and Hamiltonian Graphs in graph theory. We prove a general version of the conjecture by R. Haggkvist; as a result, we prove two extended versions of two well-known theorems due to O. Ore and B. Ja... 详细信息

关键词： k-factor 2-connected graph Hamilton cycle