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Annular electromagnetic stirring——a new method for the production of semi-solid A357 aluminum alloy slurry

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Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 408-414页

作者： Guanglei ZHU jun XU zhifeng zhang Yuelong BAI likai shi National Engineering ＆ Technology Research Center for Non-ferrous Metal Matrix Composites General Research Institute for Non-ferrous Metals Beijing 100088 China

A new method for producing semisolid slurry, annular electromagnetic stirring （AEMS）, to refine and spheroidize grains was exploited. Experimental work was undertaken to investigate the effects of cooling rate, stirring power and stirring time on the solidification behavior of A357 alloy using A-EMS. It was found that increasing the cooling rate and stirring power gave rise to substantial grain refinement, which could be attributed to the increase of effective nucleation rate caused by the extremely uniform temperature and composition fields in the bulk liquid during the initial stage of solidification. Results showed that a fully grain refined spherical structure could be obtained using proper processing conditions within 10 s.

关键词： Semisolid Annular electromagnetic stirring A357

Break-up Process of Perturbed Molten Metal Jet and Preparation of Lead-Free Solder Balls

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Journal of Rare Earths 2004年第Z2期22卷 174-177页

作者： He Lijun zhang Shuguang zhang Shaoming Xu jun shi likai National Engineering Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous MetalsBeijing 100088China

Solder balls, which are used in advanced electronics packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) to substitute the leads and realize the electrical and mechanical connections between substrate and chip,have severe specifications in diameter tolerance, roundness and surface quality, and therefore challenge the traditional technologies for fabrication of metallic particles and powders. The present work made a survey of perturbed molten metal jet break-up process, observed the formation and growth of capillary wave of tin-lead melt jet by way of rapid solidification, and on the basis of the above research, successfully obtained tin-lead eutectic and Sn-4.0Ag-0.5Cu lead free solder balls with tight distribution and good sphericity of particles through optimization of processing parameters, forming a solid base for cost effectively producing solder balls.

关键词： solder balls jet break-up capillary wave perturbation

Numerical simulation on electromagnetic field,flow field and temperature field in semisolid slurry preparation by A-EMS

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Rare Metals 2010年第6期29卷 635-641页

作者： zhang zhifeng,CHEN Xingrun,XU jun,and shi likai National Engineering & Technology Research Center for Nonferrous Metal Matrix Composites,General Research Institute for Nonferrous Metals,Beijing 100088,China National Engineering & Technology Research Center for Nonferrous Metal Matrix Composites General Research Institute for Nonferrous Metals Beijing China

A two-dimensional computational model coupling an annular electromagnetic stirring（A-EMS） with a macroscopic heat and fluid flow analysis in Al-alloys semisolid slurry preparation was *** dynamic evolutions of the electromagnetic field,flow field,and temperature field were presented successfully by commercial software ANSYS 10.0 with corresponding experimental verification.A horizontally rotational electromagnetic field and,thereby,a more intensive velocity field were uniformly distributed in the stirred melt even at commercial frequency,and thus,a lower temperature difference in the stirred melt and subsequent uniformly fine microstructures were obtained compared with the normal electromagnetic *** simulation results were in good agreement with experimental ones.

关键词： metal forming electromagnetic stirring numerical analysis semisolid slurry

Effect of operating parameters on the performance of thermally regenerative ammonia-based battery for low-temperature waste heat recovery

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Chinese Journal of Chemical Engineering 2021年第4期34卷 335-340页

作者： Yu shi Liang zhang jun Li Qian Fu xun Zhu Qiang Liao Yongsheng zhang Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of EducationChongqing 400030China

This study investigated the important factors that affect the operating parameters of thermally regenerative ammoniabased batteries(TRABs),including the metal electrode type,membrane type,electrode surface area,electrode distance,electrolyte concentration,and ammonia *** experimental results showed that the maximum power density of TRABs with a Cu electrode was 40.0 W·m^(2),which was considerably higher than that with Ni(0.34 W·m^(2))and Co(0.14 W·m^(2))*** with an anion exchange membrane had a 28.6%higher maximum power density than those with a cation exchange *** increased electrode surface resulted in an increased maximum power but a decreased maximum power *** a certain range,TRAB performance was enhanced with decreased electrode distance and increased electrolyte *** increased ammonia concentration resulted in enhanced ammonia transfer and improved the TRAB performance.

关键词： Electrochemistry Thermally regenerative ammonia-based battery Recovery Renewable energy

Structural evolution of non dendritic AlSi7Mg alloy during reheating

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中国有色金属学会会刊：英文版 1999年第3期9卷 553-556页

作者： zhang Kui(张奎) zhang Yongzhong(张永忠) Liu Guojun(刘国均) Xu jun(徐骏) zhang Jingxin(张景新) Fan Jianzhong(樊建中) shi likai(石力开) Gen Res Inst NonFerrous Met Beijing 100088 Peoples R China

The structural evolution of non dendritic AlSi7Mg alloy during reheating in resistance furnace was studied. The alloy ingots were produced by electromagnetic stirring during solidification. It was found that, the Si phase in eutectic dissolves in a way of diffusion toward α phase, its appearance changes from flake to dot like, and tends to be fine and spheroidal with increasing reheating temperature. The thinner the flake, the lower the temperature for the occurrence of this process, and the higher the transforming speed. The eutectic melts partially when Si phase dissolves to some extent, and the morphology and size of primary α phase begin to change. The dendrite and rosette α phases tends to sphericize. The size of the former becomes larger, while the size of the latter reduces to be 1/2～1/4 of the original size. The spheroidal primary α phase has a tendency of grain growth.

关键词： aluminum alloys reheating non dentritic structure transformationDocument code: A

Graphene oxide modified membrane for alleviated ammonia crossover and improved electricity generation in thermally regenerative batteries

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Chinese Chemical Letters 2023年第2期34卷 485-488页

作者： Yongsheng zhang Yu shi Liang zhang jun Li Qian Fu xun Zhu Qiang Liao Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing UniversityMinistry of EducationChongqing 400030China Institute of Engineering Thermophysics School of Energy and Power EngineeringChongqing UniversityChongqing 400030China

Thermally regenerative batteries(TRBs) are promising for harvesting low-grade waste heat into electrical power. However, the ammonia crossover from anode to cathode causes self-discharge and then leads to the decay of capacity. To alleviate the ammonia crossover and improve electricity generation, a stable graphene oxide(GO) modified anion exchange membrane(AEM) was proposed. Compared with the original AEM, the GO modified AEM with a 39.5% lower ammonia permeability induces a 24.3% higher maximal power output and 20.2% higher energy density in TRBs. Together with the visualization result,it was demonstrated the ammonia crossover was effectively alleviated by GO modifying the AEM not at a cost of the reduced battery performance, indicating the promising application in future TRBs.

关键词： Thermally regenerative batteries Ammonia crossover Surface modification Graphene oxide Electrophoretic deposition

Effects of deformation parameters on microstructure and mechanical properties of magnesium alloy AZ31B

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Rare Metals 2006年第z2期25卷 105-110页

作者： zhang Shaoming YANG Bicheng XU jun shi likai CHEN Guoliang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China General Research Institute for Non-Ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Plastic deformation and dynamic recrystallization (DRX) behaviors of magnesium alloy AZ31B during thermal compression and extrusion processes were studied. In addition, effects of deformation temperature and rates on the microstructure and mechanical properties were investigated. The results show that the DRX grains nucleate initially at the primary grain boundaries and the twin boundaries, and the twinning plays an important role in the grain refinement. The DRX grain size depends on the deformation temperature and strain rate The average grain size is only 1 μm when the strain rate is 5 s-1 and temperature is 250 ℃. It is also found that the DRX grain can grow up quickly at the elevated temperature. The microstructure of extruded rods was consisted of tiny equal-axis DRX grains and some elongated grains. The rods extruded slowly have tiny grains and exhibit good mechanical properties.

关键词： magnesium alloy thermal simulation extrusion dynamic recystallization

Plasmakinetic enucleation of prostate versus 160-W laser photoselective vaporization for the treatment of benign prostatic hyperplasia

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Asian Journal of Andrology 2017年第1期19卷 15-19页

作者： Si-jun Wang Xiao-Nan Mu Ji Chen xun-Bo Jin shi-Bao zhang Long-Yang zhang Department of Urology Jinan Central Hospital Affiliated to Shandong University Jinan 250013 P.R. China Department of Concerning Foreign Affairs Jinan Central Hospital Affiliated to Shandong University Jinan 250013 P.R. China Department of Minimally Invasive Urology Provincial Hospital Affiliated to Shandong UniversityJinan 250021 P.R. China.

To evaluate the safety and efficacy of plasmakinetic enucleation of the prostate （PKEP） for the treatment of symptomatic benign prostatic hyperplasia （BPH） compared with 160-W lithium triboride laser photoselective vaporization of the prostate （PVP）. From February 2011 to July 2012, a prospective nonrandomized study was performed. One-hundred one patients underwent PKEP, and 110 underwent PVP. No severe intraoperative complications were recorded, and none of the patients in either group required a blood transfusion. Shorter catheterization time （38.14 ± 23.64 h vs 72.54 ± 28.38 h, P 〈 0.001） and hospitalization （2.32 ± 1.25 days vs 4.07±1.23 days, P 〈 0.001） were recorded in the PVP group. At 12-month postoperatively, the PKEP group had a maintained and statistically improvement in International Prostate Symptom Score （IPSS）（4.07 ±2.07 vs 5.00 ±2.10; P〈 0.001）, quality of life （QoL）（1.08 ± 0.72 vs 1.35 ± 0.72; P= 0.007）, maximal urinary flow rate （Qmax）（24.75±5.87 ml s^-1 vs 22.03 ±5.04 ml s^-1; P 〈 0.001）, postvoid residual urine volume （PVR）（14,29 ± 6,97 ml vs 17.00±6.11 ml; P = 0,001）, and prostate-specific antigen （PSA） value （0.78 ±0.57 ng ml^-1 vs 1.27 ±1.07 ng ml^-1; P 〈 0.001）. Both PKEP and PVP relieve low urinary tract symptoms （LUTS） due to BPH with low complication rates. PKEP can completely remove prostatic adenoma while the total amount of tissue removed by PVP is less than that can be removed by PKER Based on our study of the follow-up, PKEP provides better postoperative outcomes than PVP.

关键词： electrosurgery laser therapy prostate prostatic hyperplasia transurethral resection of prostate

Thermoelectric properties of heavily Co-doped β-FeSi_(2)

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Journal of Materials Science & Technology 2024年第20期187卷 248-257页

作者： jun Cheng Lu Gan c Jiawei zhang Jinyang Xi Lili Xi Jiong Yang Tingting Deng Pengfei Qiu xun shi Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Materials Genome Institute Shanghai UniversityShanghai 200444China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

Element doping is a widely employed strategy to enhance the thermoelectric(TE)properties of various materials.β-FeSi_(2)is a promising low-cost high-temperature TE material with exceptional thermal stabil-ity;however,the doping limit ofβ-FeSi_(2)is usually very low,which limits the tunability of electrical and thermal ***,a high doping content of 0.16 inβ-FeSi_(2)has been achieved by the introduc-tion of iridium(Ir),leading to the highest reported figure of merit(zT)of 0.6 inβ-FeSi_(2).Motivated by the successful heavy doping with Ir,this work aims to explore element heavy doping inβ-FeSi_(2)with cobalt(Co),a cheaper,more readily available dopant with a smaller atomic radius and closer electronegativity to iron(Fe).In this study,we successfully obtained a record-high doping content of 0.24 in Co-dopedβ-FeSi_(2)through a prolonged annealing *** the absence of a substantial enhancement in the zT of Co-dopedβ-FeSi_(2)at high doping levels,with a maximum zT of 0.3 at 900 K in Fe_(0.92)Co_(0.08)Si_(2),we observed a transition in the carrier transport mechanism as a function of Co doping content,attributed to changes in the band *** a low Co doping content(x≤0.12),Fe1-x Cox Si_(2)demonstrates dominant carrier transport via impurity levels within the band gap,exhibiting hopping *** the Co dop-ing content increases(x>0.16),the impurity levels overlap and form an impurity band,and the carrier transport turns into the impurity band *** observed band conduction behavior of Fe1-x Cox Si_(2)(x>0.16)mirrors that of Ir-dopedβ-FeSi_(2),but Fe1-x Cox Si_(2)shows much lower mobility,which can be at-tributed to the localized feature of the impurity band introduced by the Co ***,this study provides insights into the heavy Co doping and its influence on the TE properties and carrier conduction mechanisms inβ-FeSi_(2),helpful for the further development of this TE system.

关键词： β-FeSi_(2) Heavy doping Hopping Band conduction