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Trap Characteristics and Their Temperature-dependence of Silicone Gel for Encapsulation in IGBT Power Modules

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CSEE Journal of Power and Energy Systems 2021年第3期7卷 614-621页

作者： Jiayu Xu Xuebao li xiang Cui Zhibin Zhao Shenyang Mo bing Ji State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China School of Engineering University of LeicesterLeicester LE17RHUK

Silicone gel is a prevailing material for encapsulation in insulated gate bipolar transistor(IGBT)power *** space charge transport behavior in silicone gel is significant to evaluate the electrical insulation *** paper focuses on the trap characteristics and electrical properties of the silicone gel,which were rarely studied *** experiments are performed on the surface potential decay of silicone gel after the charge ***,the energy distributions of electron or hole traps are determined by a double-trap energy level model,which can be fitted by the Gaussian *** addition,the mobilities of positive and negative charges are determined,which are 1.38×10^(-12) m^(2)·V^(-1)·s^(-1) and 1.74×10^(12) m^(2)·V^(-1)·s^(-1),***,considering the heat as a byproduct resulting in thermal issues,the temperature-dependence of surface potential decay characteristics are also studied in this *** temperature rises,the decay rate of surface potential increases,especially when the temperature is higher than 80℃.Finally,the contrastive analysis illustrates that the trap characteristics of silicone gel are between the trap characteristics in liquid-state material and solid-state material,which supports the phenomenon that silicone gel is more resistive to the sharp edges in power *** work can provide a useful reference for the design of encapsulation in high-voltage IGBT power modules.

关键词： Charge mobility IGBT power modules silicone gel temperature-dependence trap characteristic

Self-propelled swimming of a flexible fllament driven by coupled plunging and pitching motions

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Journal of Hydrodynamics 2021年第1期33卷 157-169页

作者： bing-lin li Yi-wei Wang Bo Yin xiang Zhang Xing Zhang The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

This paper numerically investigates the self-propelled swimming of a flexible filament driven by coupled pitching and plunging motions at the leading *** influences of bending rigidity and some actuation parameters(including the phase offset between pitching and plunging,and the amplitudes of pitching and plunging motions)on the swimming performance are *** is found that with increasing rigidity,the swimming style gradually transits from the undulatory mode to the oscillatory *** plunging-pitching actuation is found to be superior to the plunging-only actuation,in the sense that it prevents the decrease of speed at high rigidity and achieves a higher efficiency across a wide range of *** comparison of the body kinematics with those of animal swimmers,and the classification of the wake structures are *** results of this study provide some novel insights for the bio-inspired design of autonomous underwater vehicles.

关键词： Self-propelled swimming flexible filament fluid-structure interaction(FSI) vortex structures immersed boundary method

An experimental study on RH vacuum chamber with a weir

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Journal of Iron and Steel Research International 2023年第10期30卷 1929-1938页

作者： Qing He Tong-lu Yao liu liu xiang-chen li bing Ni Long-fei li Metallurgical Technology Research Department Central Iron and Steel Research Institute Co.Ltd.Beijing 100081China

A new Ruhrstahl-Heraeus(RH)equipment with a weir added to the vacuum chamber was designed to help improve refining efficiency of low-carbon steel *** flow characteristics of the new RH equipment and a traditional RH equipment were evaluated and compared through water modeling experiments and an optimized calculation *** the water experiments,the mixing time,the residence time and the circulation flow rates were measured,and the flow simulating molten steel in the vacuum was *** results show that the decarburization efficiency in the new RH equipment is much *** mixing time is equal to or less than that of the latter when the gas flow rate is higher than 2.33 m^(3)/*** proportion of the piston flow increases by at least 40%,and the proportion of the well-mixed flow decreases from greater than 40%to less than 20%.The effective flow rate of the new RH equipment increases greatly in the piston flow zone and the total lag flow zone based on the residence time distribution *** conclusion,when a weir is added to a RH vacuum chamber,the effective circulation flow increases significantly,and the decarburization rate KC of molten steel at low-carbon stage is improved.

关键词： Ruhrstahl-Heraeus Weir Water modeling Residence time distribution Decarburization

Tracing environmental lead sources on the Ao mountain of China using lead isotopic composition and biomonitoring

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Journal of Mountain Science 2017年第7期14卷 1358-1372页

作者： xiang Zhong-xiang bing Hai-jian WU Yan-hong ZHOU Jun li Rui HE Xiao-li The Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Atmospheric lead （Pb） and other trace metals can transport over long distance and deposit on remote alpine ecosystems. In this work, the soil profiles, litter and dominant mosses along a large altitude were collected on Ao Mountain, Central China, to obtain the spatial distributions of Pb in these materials, decipher the possible factors controlling the distribution, and quantitatively distinguish the natural versus anthropogenic sources of Pb through the Pb isotopic tracing and biomonitoring. The results show that soil Pb concentrations （mg/kg） decreased significantly with depth, and they were markedly higher in the 0 （42.6 ＋ 2.7） and A （36.4 ＋ 2.2） horizons than in the litter （7.20 ~ 1.9） and mosses （28.o ~ 3-9）- The Pb enrichment in the surface soils （0 and A horizons）, litter and mosses existed in the relatively high altitudes, which was attributed to the influences from atmospheric wet deposition, plants, soil Dhvsicochemical DroDerties and human activitv. ThePb isotopic ratios identified the Pb sources as originating mainly from Chinese coal combustion, mining and smelting. Atmospheric Pb from southeastern, southwestern and northwestern regions could be deposited in the alpine ecosystem by long distance atmospheric transport. The anthropogenic Pb reached over 50% in the 0 and A horizons, and over 70% in the litter and mosses, which corresponded to the concentrations of 26.9, 17.7, 5.92 and 21.2 mg/kg, respectively. The results indicate that the mutual effects of climate and regional human activity could increase the Pb accumulation in remote alpine ecosystems.

关键词： Source identification Pb isotope Biomonitoring Mountain soils Qinling region

Is total laparoscopic pancreaticoduodenectomy superior to open procedure? A meta-analysis

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World Journal of Gastroenterology 2019年第37期25卷 5711-5731页

作者： Hua Zhang xiang Lan bing Peng Bo li Department of liver Surgery and liver Transplantation Center West China Hospital of Sichuan UniversityChengdu 610041Sichuan ProvinceChina Department of Pancreatic Surgery West China Hospital of Sichuan UniversityChengdu 610041Sichuan ProvinceChina

BACKGROUND Laparoscopy has been widely used in general surgical procedures,but total laparoscopic pancreaticoduodenectomy(TLPD)is still a complex and challenging surgery that is only performed in a small number of patients at a few large academic medical *** the safety and feasibility of TLPD have been established,few studies have compared it with open pancreaticoduodenectomy(OPD)with regard to perioperative and oncological ***,we carried out a meta-analysis to evaluate whether TLPD is superior to *** To compare the treatment outcomes of TLPD and OPD in order to assess the safety and feasibility of *** We conducted a systematic search of studies comparing TLPD with OPD that were published in the PubMed,EMBASE,and Cochrane library databases through December 31,*** studies comparing TLPD and OPD with at least one of the outcomes we were interested in and with more than 10 cases in each group were included in this *** Newcastle-Ottawa scale was used to assess the quality of the nonrandomized controlled trials and the Jadad scale was used to assess the randomized controlled *** data,postoperative complications,and oncologic outcomes were *** metaanalysis was performed using Review Manager Software version *** or fixed-effects meta-analyses were undertaken to measure the pooled *** A total of 4790 articles were initially identified for our *** screening,4762 articles were excluded and 28 studies representing 39771 patients(3543 undergoing TLPD and 36228 undergoing OPD)were eventually *** who underwent TLPD had less intraoperative blood loss[weighted mean difference(WMD)=-260.08 mL,95%confidence interval(CI):(-336.02,-184.14)mL,P<0.00001],a lower blood transfusion rate[odds ratio(OR)=0.51,95%CI:0.36-0.72,P=0.0001],a lower perioperative overall morbidity(OR=0.82,95%CI:0.73-0.92,P=0.0008),a lower wound infection rate(OR=0.48,95%CI:0.34-0.67,P<0.0001)

关键词： Total laparoscopic pancreaticoduodenectomy Open pancreaticoduodenectomy Safety Feasibility Meta-analysis

Effect of Nitrogen Content on Primary Recrystallization Behavior and Magnetic Property of Hi-B Steel

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Journal of Iron and Steel Research International 2016年第10期23卷 1080-1085页

作者： Hai-jun WANG bing FU li xiang Zhe RONG Sheng-tao QIU National Engineering Research Center of Continuous Casting Technology Central Iron and Steel Research Institute School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The effect of nitrogen content on primary recrystallization microstructure,texture and magnetic property of Hi-B steel was studied by means of optical microscopy（OM）,scanning electron microscopy（SEM）,and electron backscatter diffraction（EBSD）.When nitrogen content increased gradually from 0.005 5% to 0.031 0%,the primary grain size and variation coefficient of nitrided sheet reduced from 26.85μm,0.590 to 18.87μm,0.525-0.565,***,the primary recrystallization texture style of nitrided sheet was nearly identical to the texture style of decarburized sheet before nitriding treatment,but exhibiting a certain change on texture *** variation of average magnetic induction value（B8）and core loss value（P17/50）were manifested to be Mshaped and W-shaped curves,*** nitrogen content reached 0.016 0%,the best value of the average magnetic property of the final product was obtained as follows：the B8 and P17/50 were 1.921 Tand 0.968W/kg,***,the best performance,B8 and P17/50,of single sheet was 1.964 Tand 0.854 W/kg.

关键词： nitriding decarburization primary recrystallization magnelic property texture Hi-B steel

Characterizing microstructure and texture after recrystallization annealing of Hi-B steel with simutaneous decarburization and nitriding

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Journal of Iron and Steel Research International 2017年第12期24卷 1215-1222页

作者： li xiang Zhe Rong bing Fu Hai-jun Wang Sheng-tao Qiu National Engineering Research Center of Continuous Casting Technology China Iron and Steel Research Institute Group School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

How to manufacture the high magnetic induction grain-oriented silicon steel（Hi-B steel）by the process featured with the primary recrystallization annealing was demonstrated,during which nitriding and decarburizing were simultaneously realized in *** the techniques of optical microscope,scanning electronic microscope and electron backscattered diffraction,both the microstructure and the texture in the samples were *** samples had been subjected to nitriding to different nitrogen contents at two specified temperatures using the two defined microstructural parameters：the grain size inhomogeneity factorσ＊and the texture factor *** former is the ratio of the mean value to standard deviation of grain sizes;the latter is the ratio of the total volume fraction of the harmful textures to that of beneficial textures including {110}〈001〉.When the N content increased from 0.0055%to 0.0330%after the annealing at both 835 and 875°C,the resultant recrystallized grain size decreased butσ＊changed little;whilst the rise of annealing temperature from 835 to 875°C resulted in the increase in both grain size andσ＊.Moreover,either the injected N content or temperature had insignificant influence on the components of primary recrystallization texture developed during ***,the increase of temperature led to the decreases in both intensity and volume fraction of{001}〈120〉and{110}〈001〉textures but increases in the{114}〈481〉andγfiber textures and the resultant decrease of AR.

关键词： Hi-B steel Simultaneous nitriding and decarburizing annealing Primary recrystallization Microstructure Texture

HOXA11-AS aggravates microglia-induced neuroinflammation after traumatic brain injury

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Neural Regeneration Research 2022年第5期17卷 1096-1105页

作者： xiang-Long li Bin Wang Fu-bing Yang li-Gang Chen Jian You Department of Neurosurgery the Affiliated Hospital of Southwest Medical UniversityLuzhouSichuan ProvinceChina Neurosurgical Clinical Research Center and Academician(Expert)Workstation of Sichuan Province LuzhouSichuan ProvinceChina Laboratory of Neurological Diseases and Brain Functions the Affiliated Hospital of Southwest Medical UniversityLuzhouSichuan ProvinceChina

Long noncoding RNAs(lnc RNAs)participate in many pathophysiological processes after traumatic brain injury by mediating neuroinflammation and *** A11 antisense RNA(HOXA11-AS)is a member of the lnc RNA family that has been reported to participate in many inflammatory reactions;however,its role in traumatic brain injury remains *** this study,we established rat models of traumatic brain injury using a weight-drop hitting device and injected LV-HOXA11-AS into the right lateral ventricle 2 weeks before *** results revealed that overexpression of HOXA11-AS aggravated neurological deficits in traumatic brain injury rats,increased brain edema and apoptosis,promoted the secretion of proinflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factorα,and promoted the activation of astrocytes and *** were treated with 100 ng/m L lipopolysaccharide for 24 hours to establish in vitro cell models,and then transfected with pc DNA-HOXA11-AS,mi R-124-3 p mimic,or *** results revealed that HOXA11-AS inhibited mi R-124-3 p expression and boosted MDK expression and TLR4-nuclear factor-κB pathway ***,lipopolysaccharide enhanced potent microglia-induced inflammatory responses in *** overexpression of mi R-124-3 p or downregulating MDK repressed microglial activation and the inflammatory response of ***,the mi R-124-3 p-mediated anti-inflammatory effects were reversed by *** findings suggest that HOXA11-AS can aggravate neuroinflammation after traumatic brain injury by modulating the mi R-124-3 p-MDK *** study was approved by the Animal Protection and Use Committee of Southwest Medical University(approval ***-2019-042)on February 4,2019.

关键词： astrocyte competitive endogenous RNA HOXA11-AS microglia midkine miR-124-3p neuroinflammation traumatic brain injury

纳米微晶Fe_(69.5)(CuCrV)_(9.5)Si_(13)B_8超铁磁性研究

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物理学报 1995年第7期44卷 1158-1163页

作者：杨燮龙胡炳元李香菁吴正金慧娟许桂琴张延忠华东师范大学物理系上海200062 上海钢铁研究所上海200940

经813K温度退火后的纳米微晶Fe_(?)(CuCrV)_(9.5)Si_(13)B_8由α-Fe(Si)晶粒和晶界两种磁相组成,温度从10—8l3K的穆斯堡尔研究显示晶粒的超精细场随着温度的变化曲线上有一个转折.用超铁磁性模型进行拟合,结果表明晶界和晶粒间存在强... 详细信息

经813K温度退火后的纳米微晶Fe_(?)(CuCrV)_(9.5)Si_(13)B_8由α-Fe(Si)晶粒和晶界两种磁相组成,温度从10—8l3K的穆斯堡尔研究显示晶粒的超精细场随着温度的变化曲线上有一个转折.用超铁磁性模型进行拟合,结果表明晶界和晶粒间存在强的交换耦合作用,使晶粒的有效磁各向异性常数减小为原来的六分之一.

关键词：微晶合金铁铜硅硼合金超铁磁性