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具有贯穿结构的铜/铝复合材料的强化及热导率

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Transactions of Nonferrous Metals Society of China 2024年第1期34卷 236-245页

作者：陈孝凌陈志青胡波严龙王静雅应韬曾小勤上海交通大学材料科学与工程学院轻合金精密成型国家工程研究中心上海200240 中国航空无线电电子研究所上海200233

为了在提高铝合金强度的同时避免降低其热导率,设计了一种具有单向贯穿结构的新型铜/铝双金属复合材料,并采用增材制造结合挤压铸造的工艺实现制备成形。该复合材料表现出较好的强度(约340 MPa)和热导率(200 W/(m·K))匹配性,综合性能... 详细信息

为了在提高铝合金强度的同时避免降低其热导率,设计了一种具有单向贯穿结构的新型铜/铝双金属复合材料,并采用增材制造结合挤压铸造的工艺实现制备成形。该复合材料表现出较好的强度(约340 MPa)和热导率(200 W/(m·K))匹配性,综合性能超过传统铝合金。这种良好的导热性能归因于单向贯穿的Cu骨架增强体结构能够为电子传导提供快速通道。同时,界面处生成Al2Cu共晶相,实现良好的界面冶金结合,有效改善复合材料的力学性能。

关键词： Cu/Al复合材料抗压强度挤压铸造技术热导率

一种提高镁合金零部件抗火焰蔓延性的尺寸设计类判据

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Transactions of Nonferrous Metals Society of China 2024年第4期34卷 1123-1135页

作者：胡波韩嘉璇李德江李子昕曾小勤丁文江林占宏金晨赵寿上海交通大学材料科学与工程学院轻合金精密成型国家工程研究中心&金属基复合材料国家重点实验室上海200240 青海盐湖特立镁有限公司西宁810000

基于能量守恒定律提出了一种用于预测棒状镁合金样品火焰蔓延时间的判据,该判据表明火焰蔓延时间主要受合金材料和样品尺寸影响。控制体的初始温度和起燃温度以及样品的S/l_c比值(样品横截面面积/横截面周长)是火焰蔓延时间的决定性因... 详细信息

基于能量守恒定律提出了一种用于预测棒状镁合金样品火焰蔓延时间的判据,该判据表明火焰蔓延时间主要受合金材料和样品尺寸影响。控制体的初始温度和起燃温度以及样品的S/l_c比值(样品横截面面积/横截面周长)是火焰蔓延时间的决定性因素。火焰蔓延时间正比于ΔH(将单位质量的样品从初始温度加热到起燃温度所需的能量)和S/l_c比值,这在Mg-8.5Al-0.5Zn-0.2Mn、Mg-2.7Nd-0.4Zn-0.6Zr和Mg-4.0Y-3.3Nd-0.5Zr镁合金中得到验证。对于尺寸相同的样品,Mg-8.5Al-0.5Zn-0.2Mn合金样品有着最大的ΔH以及最长的火焰蔓延时间;对于材质、长度和横截面面积相同的样品,圆形横截面样品的S/lc比值最大,其抗火焰蔓延性能也最佳。

关键词：镁合金零部件抗火焰蔓延性显微组织尺寸设计判据

Effect of double aging on mechanical properties and microstructure of EV31A alloy

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Transactions of Nonferrous Metals Society of China 2021年第9期31卷 2606-2614页

作者： Kan GU xiao-qin zeng Bin CHEN Ying-xin WANG School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240China

To improve the ductility of a commercial Mg−rare earth alloy EV31A(Mg−3Nd−1.5Gd−0.3Zn−0.5Zr),a heat treatment method called double aging is explored,and its effect on mechanical properties and microstructure of the alloy is *** strength and elongation of the alloy can be increased to 288 MPa and 6.6%by the optimum double aging process,compared to 273 MPa and 4.9%after single *** consumption of the aging process is also significantly decreased from 16 h(single aging)to 2 ***-STEM characterization shows that the primary precipitate isβ'phase,which is similar toβ'phase in Mg−Nd binary *** double aging,theβ'phase is finer and more densely distributed compared with single aging,with approximately double density and half size,which explains the improvement in strength and ductility.

关键词： magnesium alloy EV31A double aging mechanical properties β'phase

Atomic relaxation,stability and electronic properties of Mg2Sn(100)surfaces from ab-initio calculations

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Journal of Magnesium and Alloys 2016年第1期4卷 62-67页

作者： Hui Ren Wen-Cheng Hu De-Jiang Li xiao-qin zeng Xue Yang xiao-Shu zeng Xiang-Jie Yang Bolong Huang Yong Liu Key Laboratory of Near Net Forming of Jiangxi Province Nanchang UniversityNanchang 330031China National Engineering Research Center of Light Alloys Net Forming Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratories of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240China Department of Physics and Materials Science City University of Hong KongKowloonHong Kong

Mg2Sn(100)surfaces were investigated using ab-initio method based on density functional theory in order to explore the surface *** is found that both the eleven-layers for Mg-termination surfaces and the nine-layers for Sn-termination surfaces are all converged very *** effects of relaxation mainly occurred within the three outermost atomic layers for both Mg and Sn terminations during the surface ***-termination surfaces are more stable than Sn-termination surfaces according to the analysis of surface *** density of states reveals the metallic property of both Mg-termination and Sn-termination *** bonding exists in Mg2Sn(100)surfaces according to the analysis of partial density of states.

关键词： Magnesium alloy Ab-initio calculation Surface energy Surface stability Electronic properties

Effects of Ce content on the modification of Mg_(2)Si phase in Mg-5Al-2Si alloy

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镁合金学报(英文) 2023年第7期11卷 2299-2311页

作者： Bo Hu Wen-Jie Zhu Zi-Xin Li Seul Bi Lee De-Jiang Li xiao-qin zeng Yoon Suk Choi National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Pusan National UniversityBusan 46241Republic of Korea The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China

The effect of Ce content(0–1.6 wt.%)on the modification of Mg_(2)Si phase in the as-cast Mg-5Al-2Si alloy was *** original Chinese script type Mg_(2)Si phase was refined distinctly and transformed to dispersive block shape gradually by adding Ce *** length of Chinese script type Mg_(2)Si phase was reduced from 110 to 50μm with increasing Ce content to 1.6 wt.%.The results calculated by Pandat software indicated that the added Ce element first combined with Si to form CeSi_(2)phase,which could serve as the heterogeneous nucleation of Mg_(2)Si phase due to the small lattice mismatch of 7.97%.The modification of Mg_(2)Si phase was mainly attributed to the facts that Ce changed the growth steps of Mg_(2)Si phase and CeSi_(2)promoted the nucleation of Mg_(2)Si *** increasing Ce content from 0 wt.%to 1.6 wt.%,the YS,UTS and EL at 150℃were improved from 67.7 MPa,91.2 MPa and 1.6%to 84.2 MPa,128 MPa and 7.5%,respectively.

关键词： Mg-Al-Si alloys Mg_(2)Si modification Heterogeneous nucleation Mechanical properties

Cluster analysis reveals a homogeneous subgroup of PCOS women with metabolic disturbance associated with adverse reproductive outcomes

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Chinese Medical Journal 2024年第5期137卷 604-612页

作者： Hanxiao Chen Rujun zeng Xun zeng Lang qin The Reproductive Medical Center Department of Obstetrics and GynecologyWest China Second University HospitalSichuan UniversityChengduSichuan 610041China Key Laboratory of Birth Defects and Related of Women and Children of Ministry of Education West China Second University HospitalSichuan UniversityChengduSichuan 610041China

Background:Polycystic ovarian syndrome(PCOS)is a heterogeneous and complex reproductive endocrinological disease that could lead to *** were many attempts to classify PCOS but it remains unclear whether there is a specific subgroup of PCOS that is associated with the best or worst reproductive outcomes of assisted reproductive techniques(ART).Methods:Infertile PCOS patients who underwent their first cycle of in vitro fertilization(IVF)in West China Second University Hospital,Sichuan University from January 2019 to December 2021 were *** clinical and laboratory information of each individual were *** cluster analysis was *** ovarian stimulation parameters and reproductive outcomes were collected and compared between the different clusters of ***:Our analysis clustered women with PCOS into"reproductive","metabolic",and"balanced"clusters based on nine *** group was characterized by high levels of testosterone(T),sex hormone-binding globulin(SHBG),follicular stimulation hormone(FSH),luteinizing hormone(LH),and anti-Müllerian hormone(AMH).Metabolic group was characterized by high levels of body mass index(BMI),fasting insulin,and fasting *** group was characterized by low levels of the aforementioned reproductive and metabolic parameters,except for *** with PCOS patients in reproductive and balanced clusters,those in metabolic cluster had lower rates of good quality day 3 embryo and blastocyst ***,PCOS patients in the reproductive cluster had greater fresh embryo transfer(ET)cancelation rate and clinical pregnancy rate after fresh ET than metabolic cluster(odds ratio[OR]=3.37,95%confidence interval[CI]:1.77-6.44,and OR=6.19,95%CI:1.58-24.24,respectively).And compared with PCOS of metabolic cluster,PCOS of balanced cluster also had higher chance for fresh ET cancelation(OR=2.83,95%CI:1.26-6.35).Conclusion:Our study suggested that PCOS patients in met

关键词： Polycystic ovarian syndrome Assisted reproductive techniques Clustering analysis Metabolic disturbance Clinical pregnancy

ANovel Non-Isolated Cubic DC-DC Converter with High Voltage Gain for Renewable Energy Power Generation System

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Energy Engineering 2024年第1期121卷 221-241页

作者： qin Yao Yida zeng qingui Jia School of Electrical Engineering Southwest Jiaotong UniversityChengdu610036China

In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device *** address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC ***,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power ***,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain ***,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic ***,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are *** theoretical analysis’s correctness is verified through simulation and experimental *** proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power *** proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy *** provides an effective solution to the issue of low output voltage in renewable energy power generation systems.

关键词： Cubic DC-DC converter high voltage gain low device stress high efficiency renewable energy

A new type of lipophilic hydrophobic self-repairing cellulose insulating paper developed with ST-110/FAS/PTFE ternary system as coating substrate

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High Voltage 2024年第2期9卷 474-483页

作者： Zhenglin zeng Jinshan qin Zuhao Wang Weimin Tan Chao Tang College of Engineering and Technology Southwest UniversityChongqingChina International R&D Center for New Technologies of Smart Grid and Equipment ChongqingChina

The moisture generated by the ageing of the oil-paper insulating system can easily lead to the deterioration of the performance of the insulating *** order to alleviate the impact of moisture on the performance of the insulating paper,we developed a kind of lipophilic hydrophobic self-repairing cellulose insulating paper(new insulating paper)based on the ternary system of polytetrafluoroethylene,fluorocarbon surfactant and fluorinated alkyl silane,and accelerated thermal ageing test for 45 days at 130°C was carried *** experimental results show that the new insulating paper with excellent lipophilic property can realise hydrophobic self-repairing through heat treatment after physical *** tensile strength and elongation at break of the new insulating paper increased by 5%–8%and 6.25%–27%respectively compared with the original cellulose insulating *** the end of ageing,the relative dielectric constant and dielectric loss factor of new insulating paper are 10.4%and 9.9%lower than that of the original cel-lulose insulating paper,while the breakdown voltage is 6.8%*** acid and moisture content produced during the ageing process of the insulating oil impregnated with new insulating paper are also less,indicating that the coating can delay the ageing of the insulating paper.

关键词： coating moisture cellulose

Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji xiao-song Zhang Chen-jun Yang xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces