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High temperature polyimide nanocomposites containing twodimensional nanofillers for improved thermal stability and capacitive energy storage performance

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Nano Research 2024年第8期17卷 7746-7755页

作者： Ding Ai Yuting Han Zongliang xie xi Pang Yuan Chang He Li Chenglong Wu Yonghong Cheng Guanglei Wu state key laboratory of Electrical Insulation and power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China Institute of Materials for Energy and Environment State Key Laboratory of Bio-Fibers and Eco-TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China

Future electronic devices toward high integration and miniaturization demand reliable operation of dielectric materials at high electric fields and elevated ***,the electrical deterioration caused by Joule heat generation remains a persistent challenge to ***,the solution-processed polyimide(PI)nanocomposites with unique two-dimensional(2D)alumina nanoplates are *** improvements in the breakdown strength,charge–discharge efficiency and discharged energy density at elevated temperatures have been demonstrated in the composites,owing to simultaneously suppressed conduction loss and increased thermal conductivity upon the incorporation of 2D Al_(2)O_(3) nanofillers possessing excellent dielectric insulation and thermophysical *** predominance of Al_(2)O_(3) nanoplates in enhancing thermal stability and high-temperature capacitive performance over nanoparticles and nanowires is validated experimentally and is further rationalized via finite element ***,the Al_(2)O_(3) nanoplates filled PI nanocomposite exhibits a hightemperature capability up to 200℃ and remarkable efficiency(e.g.≥95% at 200 MV/m)over a wide temperature range,which outperforms commercial dielectric polymers and rivals the state-of-the-art polyimide nanocomposites.

关键词： capacitors polymer nanocomposites high temperature energy storage thermal stability

flow visualization of silicon-based micro pulsating heat pipes

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Science china(Technological Sciences) 2010年第4期53卷 984-990页

作者： QU Jian & WU HuiYing key laboratory for power Machinery and engineering of Ministry of Education,School of Mechanical engineering,Shanghai jiaotong university,Shanghai 200240,china 1. key laboratory for power Machinery and engineering of Ministry of Education School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200240 China

Two sets of silicon-based micro pulsating heat pipes(SMPHPs) with trapezoidal cross section having hydraulic diameters of 352 μm(#1) and 394 μm(#2) respectively were fabricated for the first time using MEMS *** FC-72 as the working fluid,the start-up,steady operation state,as well as flow patterns were investigated using a CCD *** was found that the start-up process of these two SMPHPs was rather *** the start-up period,no nucleation was observed,and the vapor plugs at the evaporator U-bends were formed mainly due to the breakup of liquid *** the steady operation state,self-sustained oscillation with large amplitudes dominated the flow behavior when the inclination angle varied from 10° to 90°,but the nucleate boiling and bulk circulation were observed only in SMPHP #*** bubbly,slug/plug,annular/semi-annular,and wavy-annular flows were observed in both two SMPHPs,the injection flow only appeared in SMPHP #2.

关键词： micro pulsating heat pipe flow visualization start-up flow pattern injection flow

The influence of the sand-dust environment on air-gap breakdown discharge characteristics of the plate-to-plate electrode

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 458-464页

作者： HE Bo1, ZHANG Gang1, CHEN BangFa1, GAO NaiKui1, LI YaoZhong2, PENG ZongRen1 & JIN HaiYun1 1 state key laboratory of Electrical Insulation and power Equipment, xi’an jiaotong university, xi’an 710049, china 2 xinjiang Electric power Research Institute, Urumqi 830011, china 1. state key laboratory of Electrical Insulation and power Equipment Xi’an Jiaotong University Xi’an 710049 China2. Xinjiang Electric Power Research Institute Urumqi 830011 China

The experiments of plane-plane gap discharge was carried out in an environment of artificial sandstorm. By comparing and analyzing the differences in gap breakdown voltage between the sand & dust environment and clean air, some problems were investigated, such as effects of wind speed and particle concentration on the breakdown voltage, differences of gap discharge characteristics between the dust & sand medium and the clean air medium. The results showed that compared with the clean air environment, the dust & sand environment had a decreased gap breakdown voltage. The longer the gap distance, the greater the voltage drop; the breakdown voltage decreased with the increase of particle concentration in flow. With the increase of wind speed, the breakdown voltage decreased at the beginning and rose afterwards. The results of the paper may helpful for further research regarding the unidentified flashover and external insulation characteristics of the HV power grid in the dust & sand environment.

关键词： external insulation air-gap breakdown sand-dust flow simulation experiment

EFFECTS　OF　PRESTRAIN　ON　FATIGUE　THRESHOLD　AND　INITIAL　YIELD　STRESS　OF　NORMALIZED　1035　STEEL

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Acta Metallurgica Sinica(English Letters) 1996年第4期9卷 247-250页

作者： J.X Luo and Y.X. Tan (state key Lab. for Mechanical Behavior of Materials xi′an jiaotong university, xi’an 710049, china )

The relationships between fatigue threshold △Kth and the initial yield .strength σ0 of normalized 1035 steel after various prestrain (at fist, second and third hardening stages respectively) were investigated through the analysis of theσ-εcurves and transmission electron microscope (TEM). After prestraining at first or second hardening stage, there is a marked drop in the values of △Kth and σ0. This is in correspondence with the depinning of the solute atoms from the dislocation lines in the Cottrell *** the third hardening stage of prestrain the fatigue threshold increases rapidly and △Kth is even 1.6 times as large as the original value. This is because at this stage no dislocation-cell free areas can be found and the refinement of the dislocation cells occurs with the increase in the prestrain level.

关键词： deformation hardening fatigue threshold initial yield strength,dislocation array,1035 steel

MIXED CONVECTIVE HEAT TRANSFER IN A HORIZONTAL CURVED TUBE UNDER SUPERCRITICAL PRESSURE

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MIXED CONVECTIVE HEAT TRANSFER IN A HORIZONTAL CURVED TUBE U...

Crystallization Growth of Single Crystal Cu by Continuous Casting

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作者： Feng Xu Liejin Guo Bofeng Baistate key laboratory of multiphase flow in power engineering xi’an jiaotong university xi’an 710049 china

＜正＞ In the present work, a numerical simulation was performed to investigate the developing mixed laminar flow and heat transfer characteristics of supercritical pressure water in a horizontal curved pipe. The flow and heat transfer have been studied in the range of curvature 5=0.01-0.1, inlet temperature Tin=600-700K, inlet Dean number Dein=200-500, inlet Grashof number Grin= 1×105-1×107 and pressure P=23MPa-30MPa. The velocity field and temperature field are given, the influence of all these different parameters on flow and heat transfer have been investigated in detail, and comparison has been made between the result of curved pipe and that of straight pipe.

关键词： supercritical mixed convection secondary flow heat transfer

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Journal of Materials Science & Technology 2000年第3期16卷 345-347页

作者： Zhenming XU and Jianguo LI (School of Materials Science and engineering, Shanghai jiaotong university, Shanghai 200030, china) Hengzhi FU (state key laboratory of Solidification Processing, Northwestern Polytechnical university, xi’an 710072, china) School of Materials Science and engineering Shanghai Jiaotong University Shanghai 200030 China state key laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China

Crystallization growth of single-crystal Cu by continuous casting has been investigated using self-designed horizontal continuous casting equipment and XRD. Experimental results showed that the crystallization plane of (311), (220) and (ill) were eliminated sequentially in evolutionary process. The final growth plane of crystal was (200), the direction of crystallization was [100], the growth direction of both sides of the rod inclined to axis, and the degree of deviation of direction [100] from the crystal axis was less than 10°. In order to produce high quality single crystal, the solid-liquid interface morphology must be smooth, even be planar.

关键词： Crystallization Growth of Single Crystal Cu by Continuous Casting Cu

EFFECT OF SPECIMEN SIZE ON J_R RESISTANCE CURVE

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Acta Metallurgica Sinica(English Letters) 1996年第5期9卷 350-354页

作者： H.P. Chen and Z.J. Deng (state key Lab. for Mechanical Behavior of Materials, xi’an jiaotong university, xi’an 710049, china)

The effect of specimen thinkness on JR resistance curve has been investigated using low and middle strength steels. As the J dominance regime is reached, the initial J-integral values, J(i), are definite even if the elastic component Ji(e) and plastic component Ji(p)vary with the thinkness of specimen. The wider the specimen width, the larger the Ji(e)/Ji and the smaller the Ji(p)/Ji. The crack propagation resistance, dJR/da and dJp/da, decreases, while dJe/da increases linearly with increasing specimen *** on the above experimental results, an empirical formula dJ/da = α+β. B is given, which can be used to evaluate the safety of practical structural components.A modified J-integral is presented, upon which a new view is Put forward that the increase in crack growth resistance is induced mainly by the increase in the plastic J-integral component with the crack propagation,

关键词： fracture mechanics J-R curve modified J elastic-plastic fracture

Synthesis of biodiesel from soybean oil and methanol catalyzed by cationic ion-exchange resin in a ultrasonic reactor

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Synthesis of biodiesel from soybean oil and methanol catalyz...

engineering design and numerical design for chemical looping combustion reactor: A review

The 4th Joint china/Japan Chemical engineering Symposium

作者： YUAN Hong YANG Bolun* and SHU QingDepartment of Chemical engineering state key laboratory of multiphase flow in power engineering xi’an jiaotong university xi’an Shaanxi 710049 china

To improve the efficiency of the production of biodiesel （Fatty Acid Methyl Ester, FAME）, a new production methodfor FAME is developed. The transesterification was carried out in a ultrasonic reactor using solid acid catalysts （cation-exchangeresin or zeolite beta） under the atmospheric condition;the average pore size for these catalysts were determined by nitrogenadsorption experiments, the FAME content in the reaction mixture were quantified by a potassium hydroxide saponification method,and the product was investigated by FTIR imaging for further structural analysis. Experimental results showed that cation-exchangeresin NKC-9 exhibited higher catalytic activity than zeolite beta, which may be correlated to the larger pore size of the NKC-9produced stronger cavitations effect. When the methanol/ soybean oil molar ratio was 20, reaction temperature at 333K, reactiontime 6 hours and catalyst/soybean oil mass ratio of 1.08wt%, the conversion of triglyceride 68.1 wt% was obtained from thisoptimal reaction condition.

关键词： biodiesel soybean oil cation-exchange resin transesterification ultrasound

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Energy Reviews 2024年第3期3卷 129-150页

作者： xi Chen Rongchao Li Ye Tao Yongqi Tong Ao Li Daofeng Mei Haibo Zhao state key laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan430074China Instituto de Carboquímica(ICB-CSIC) Miguel Luesma Castan450018ZaragozaSpain

Chemical looping combustion(CLC)has emerged as a cost-effective technology for carbon capture at the combustion *** reactor,being central to the implementation of CLC,primarily adheres to two technological pathways:the dual fluidized bed reactor and the packed bed ***,the intricate interaction between gas-solid reaction flow and heat/mass transfer processes in these reactors gives rise to diverse operational principles at both macroscopic and microscopic levels across various reactor forms and scales,making performance prediction ***,the rational design of CLC reactors poses a significant challenge in advancing this technology to commercial *** article offers an extensive review of the prevailing reactor designs in CLC,delving into reactor characteristics,pivotal aspects of the design process,methodologies,and representative studies in the *** predominant reactor design approaches are categorized into engineering and numerical *** former encompasses phenomenological and similarity analysis methods,whereas the latter consists of macroscopic and computational fluid dynamics simulation *** method possesses its theoretical framework,distinctive characteristics,appropriate applications,and respective advantages and *** practical applications,integrating these aspects is *** instance,the engineering design,which is less costly but also less precise,is effective for quickly screening numerous potential design *** contrast,the numerical design,despite its higher computational demand and greater model complexity,offers improved predictive accuracy and is optimal for validating and refining engineering design solutions.

关键词： Carbon capture Chemical looping combustion Reactor design engineering design Numerical design