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Influence of sintering time on microstructure and properties of hot oscillatory pressing sintered W–Cu refractory alloys

第三届教学管理与课程建设学术会议

作者： xiaoming shi 1 , wei qian 2.1 school of mechanical engineering,{2., shanghai, China 2.school of mechanical engineering,{2., shanghai, China

Cultivating the sense of innovation in university students is one of the aims for institutions of higher education in China. We attempt to explore a system of cultivating extracurricular scientific and technological innovation in the University of shanghai for Science and Technology. The exploration is made from both the macro perspective and the micro procedures, in combination with taking advantage of the considerable teaching resources if necessary. General principles, specific methods and particular activities in this system are discussed in detail. The research serves to be supplementary work concerning the cultivation of the sense of innovation among university students given the success we have achieved.

关键词： Education Model University Students Innovation Cultivating System

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Tungsten 2024年第2期6卷 323-332页

作者： Zi-qian Wu wei Zhao Ka Gao {2.-Hao Du Qing-Quan Kong De-Jian Sun Yang Gao school of Materials Science and engineering Zhengzhou University of AeronauticsZhengzhou 450015China school of mechanical {2. University of Shanghai for Science and TechnologyShanghai 200093China Department of General Medicine Changhai HospitalShanghai 200000China Hubei Key Laboratory of mechanical Transmission and Manufacturing engineering Wuhan University of Science and TechnologyWuhan 430081China Sichuan Province engineering Technology Research Center of Powder Metallurgy Chengdu UniversityChengdu 610106China

W–Cu refractory alloys are widely used in aerospace,aviation,electronics,power,and other fi ***,because of its large melting point diff erence between alloy elements,the conventional powder metallurgy method required a long time of high temperature sintering is very likely to cause low density and abnormal grain size ***,90W-10Cu refractory alloys were successfully prepared by hot oscillatory pressing(HOP)under diff erent sintering time in this *** the infl uence of sintering time on the microstructure,grain size,density,Vickers hardness,room-tensile property,and electrical conductivity of the W–Cu refractory alloy was systematically *** results showed that during the short sintering time(30–90 min),the density,Vickers hardness,tensile strength,and electrical conductivity of the W–Cu refractory alloy increased signifi cantly to 98.7%,163.2. HV 30,507.3 MPa,and 14.2.International Annealed Copper Standard with the sintering time increasing,respectively,while its grain size showed no obvious *** the sintering time further increased to 12. min,the density was basically consistent with the sintering time of 90 ***,the prolonged high temperature sintering resulted in the grain growth of the samples,which caused the deterioration of the Vickers hardness,room-tensile strength,and conductivity properties of the W–Cu refractory *** the same sintering time,the density,Vickers hardness,and electrical conductivity of the HOP sintered W–Cu refractory alloy were signifi cantly higher than those of the HP sintered *** was indicated that high density,fi ne-grain,and excellent properties W–Cu refractory alloys could be prepared by hot oscillatory pressing under appropriate sintering time.

关键词： W–Cu refractory alloy Hot oscillatory pressing Sintering time Microstructure Property

The Adjustment Analysis Method of the Active Surface Antenna Based on Convolutional Neural Network

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Research in Astronomy and Astrophysics 2024年第6期24卷 294-306页

作者： You Ban Shang shi Na Wang qian Xu Shufei Feng school of mechanical {2. Xinjiang UniversityUrumqi 830017China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China school of mechanical {2. Dongguan University of TechnologyDongguan 523808China

Active surface technique is one of the key technologies to ensure the reflector accuracy of the millimeter/submillimeter wave large reflector *** antenna is complex,large-scale,and high-precision equipment,and its active surfaces are affected by various factors that are difficult to comprehensively deal *** this paper,based on the advantage of the deep learning method that can be improved through data learning,we propose the active adjustment value analysis method of large reflector antenna based on deep *** method constructs a neural network model for antenna active adjustment analysis in view of the fact that a large reflector antenna consists of multiple panels spliced *** on the constraint that a single actuator has to support multiple panels(usually 4),an autonomously learned neural network emphasis layer module is designed to enhance the adaptability of the active adjustment neural network *** classical 8-meter antenna is used as a case study,the actuators have a mean adjustment error of 0.002.2.mm,and the corresponding antenna surface error is0.0052. *** active adjustment result shows the effectiveness of the method in this paper.

关键词： techniques:radar astronomy telescopes methods:analytical methods:numerical

Thermal Comfort in Waiting Room at Railway Station in Cold Region in China

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湖南大学学报（自然科学版） 2009年第S1期36卷 66-70页

作者： MA wei-wu,CHEN qian-zhou,ZHOU Jie-min,{2. Xiang-nan,LI Li-qing,WANG Chao,CHEN Zhi-ya(1.school of Energy Science and {2.,Central South University,Changsha,Hunan 410083,China 2.Department of mechanical {2.,Purdue University,Calumet,Hammond 4632.,USA 3.school of Traffic and Transportation {2.,Central South University,Changsha,Hunan 410083,China) school of Energy Science and engineering Central South University Changsha 410083 China Department of mechanical engineering Purdue University Calumet Hammond 46323 United States school of Traffic and Transportation engineering Central South University Changsha 410083 China

A field study and analysis about the thermal comfort was carried out in the waiting room at Beijing West Rail Station in Chinese cold ***' TSV(thermal sense vote)was obtained using statistical method on the basis of more than 1 2.0 *** linear regression between TSV and indoor temperature indicates that thermal neutral temperature is 2..2.℃.According to the percentage of satisfaction among all passengers under different indoor temperatures,the acceptable temperature range in the waiting room is 2..2.30.2..It is also found that passengers' temporary stay should be taken into consideration for the thermal comfort ***' TSV is not a constant value after they enter the waiting *** fact,ΔTSV increases as passengers are waiting for the train,and the growing rate is dependent on indoor-outdoor temperature *** greater the temperature difference,the faster ΔTSV *** last,a linear regression between indoor comfortable temperature and outdoor temperature was generated as the adaptive comfort model.

关键词： waiting room thermal comfort adaptive comfort model

Advancements in machine learning for material design and process optimization in the field of additive manufacturing

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China Foundry 2024年第2期21卷 101-115页

作者： Hao-ran Zhou Hao Yang Huai-qian Li Ying-chun Ma Sen Yu Jian shi Jing-chang Cheng Peng Gao Bo Yu Zhi-quan Miao Yan-peng {2. National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of mechanical engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China school of Materials Science and engineering Nanyang Technological University639798Singapore

Additive manufacturing technology is highly regarded due to its advantages,such as high precision and the ability to address complex geometric ***,the development of additive manufacturing process is constrained by issues like unclear fundamental principles,complex experimental cycles,and high *** learning,as a novel artificial intelligence technology,has the potential to deeply engage in the development of additive manufacturing process,assisting engineers in learning and developing new *** paper provides a comprehensive overview of the research and applications of machine learning in the field of additive manufacturing,particularly in model design and process ***,it introduces the background and significance of machine learning-assisted design in additive manufacturing *** then further delves into the application of machine learning in additive manufacturing,focusing on model design and process ***,it concludes by summarizing and forecasting the development trends of machine learning technology in the field of additive manufacturing.

关键词： additive manufacturing machine learning material design process optimization intersection of disciplines embedded machine learning

VMMAO-YOLO:an ultra-lightweight and scale-aware detector for real-time defect detection of avionics thermistor wire solder joints

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Frontiers of mechanical engineering 2024年第3期19卷 77-92页

作者： Xiaoqi YANG Xingyue LIU qian WU Guojun WEN Shuang MEI Guanglan LIAO Tielin shi school of mechanical {2. and Electronic Information China University of GeosciencesWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The quality of the exposed avionics solder joints has a significant impact on the stable operation of the inorbit ***,the previously reported inspection methods for multi-scale solder joint defects generally suffer low accuracy and slow detection ***,a novel real-time detector VMMAO-YOLO is demonstrated based on variable multi-scale concurrency and multi-depth aggregation network(VMMANet)backbone and“one-stop”global information gather-distribute(OS-GD)*** with infrared thermography technology,it can achieve fast and high-precision detection of both internal and external solder joint ***,VMMANet is designed for efficient multi-scale feature extraction,which mainly comprises variable multi-scale feature concurrency(VMC)and multi-depth feature aggregation-alignment(MAA)*** can extract multi-scale features via multiple fix-sized and deformable convolutions,while MAA can aggregate and align multi-depth features on the same order for feature *** allows the low-level features with more spatial details to be transmitted in depth-wise,enabling the deeper network to selectively utilize the preceding inference *** VMMANet replaces inefficient highdensity deep convolution by increasing the width of intermediate feature levels,leading to a salient decline in *** OS-GD is developed for efficacious feature extraction,aggregation and distribution,further enhancing the global information gather and deployment capability of the *** a self-made solder joint image data set,the VMMAOYOLO achieves a mean average precision mAP@0.5 of 91.6%,surpassing all the mainstream YOLO-series ***,the VMMAO-YOLO has a body size of merely 19.3 MB and a detection speed up to 119 frame per second,far superior to the prevalent YOLO-series detectors.

关键词： defect detection of solder joints VMMAO-YOLO ultra-lightweight and high-performance multiscale feature extraction VMC and MAA modules OS-GD

无压渗透法制备SiC颗粒增强铝基复合材料的研究

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天津大学学报（自然科学与工程技术版） 2003年第4期36卷 418-423页

作者：石锋钱端芬吴顺华天津大学电子信息工程学院天津300072 湖南大学材料科学与工程学院长沙410082

利用无压渗透法制备出SiCp/Al复合材料,研究了SiCp/Al系统的界面微观结构及复合材料的机械性能.研究表明:SiCp/Al系统的界面处存在着界面反应,生成Si、Al2.3和Al3C4等产物,在界面处存在着Si和Mg元素的富集;复合材料的机械性能受界面反应... 详细信息

利用无压渗透法制备出SiCp/Al复合材料,研究了SiCp/Al系统的界面微观结构及复合材料的机械性能.研究表明:SiCp/Al系统的界面处存在着界面反应,生成Si、Al2.3和Al3C4等产物,在界面处存在着Si和Mg元素的富集;复合材料的机械性能受界面反应和Si元素富集的影响,其中界面反应是最重要的影响因素.当界面反应控制在一定程度时,在基体与增强相的界面处形成比较充分的"机械绞合",才会使复合材料的机械性能有较大提高.界面上Si元素的富集对机械性能的影响较为复杂,一方面它可以控制界面反应的过度发生,另一方面又会产生晶格畴变,这两方面效应的叠加,使之对复合材料机械性能的影响减弱,远小于界面反应对机械性能的影响.

关键词： SiC颗粒增强铝基复合材料无压渗透法微观结构机械性能界面反应 Si元素富集

Blackening failure of poly-α-olefin impregnated porous polymide due to the splitting of lubrication oil catalyzed by iron

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Friction 2024年第9期12卷 1969-1979页

作者： Pengfei shi Yang YIN Shaohua ZHANG Diankai ZHANG Yuanyuan JIANG Yang WANG Ningning ZHOU Tao QING Jintao WU Linmao qian Jiyang ZHANG Lei CHEN Tribology Research Institute State Key Laboratory of Rail Transit Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100094China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Lubrication failure accompanying with blackening phenomenon significantly reduces the long-running operational reliability of porous polymide(PPI)lubricated with poly-α-olefin(PAO)***,the effects of lubrication condition and counter-surface chemistry on the blackening failure of PAO impregnated PPI were studied through the comparison of the tribological tests against GCr15 steel ball and Al_(2.O_(3)ceramic ball with and without PAO oil *** products were found to be formed on the PAO impregnated PPI surface slid against steel ball or Al_(2.O_(3)ball added with iron nano-particles,but be absent under the conditions without iron or PAO *** analysis indicated that the iron-catalyzed splitting of PAO oil into small molecule alkanes and following the formation of black organic matter should be mainly responsible for the blackening *** dynamic(MD)simulations demonstrated that the iron facilitated the separation of hydrogen atom and the following broken of C–C bonds in PAO molecules,final resulting in the splitting of PAO oil.

关键词： porous polyimide poly-α-olefin oil friction-induced blackening phenomenon tribological performance ReaxFF MD simulation

Flexible wide-range multidimensional force sensors inspired by bones embedded in muscle

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Microsystems & Nanoengineering 2024年第3期10卷 49-61页

作者： Jie Zhang Xiaojuan Hou Shuo qian Jiabing Huo Mengjiao Yuan Zhigang Duan Xiaoguang Song HuiWu Shuzheng shi Wenping Geng Jiliang Mu Jian He Xiujian Chou Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China school of Software North University of ChinaTaiyuan 030051China school of mechanical {2. Hebei University of ArchitectureZhangjiakou 075000China HBIS Group Co.Ltd. Shijiazhuang 050023China

Flexible sensors have been widely studied for use in motion monitoring,human‒machine interactions(HMIs),personalized medicine,and soft intelligent ***,their practical application is limited by their low output performance,narrow measuring range,and unidirectional force ***,to achieve flexibility and high performance simultaneously,we developed a flexible wide-range multidimensional force sensor(FWMFS)similar to bones embedded in muscle *** adjustable magnetic field endows the FWMFS with multidimensional perception for detecting forces in different *** multilayer stacked coils significantly improved the output from theμV to the mV level while ensuring FWMFS *** optimized FWMFS exhibited a high voltage sensitivity of 0.2.7 mV/N(0.5–8.4 N)and 0.047 mV/N(8.4–60 N)in response to normal forces ranging from 0.5 N to 60 N and could detect lateral forces ranging from 0.2.1.1 N and voltage sensitivities of 1.039 mV/N(0.2.0.5 N)and 0.194 mV/N(0.5–1.1 N).In terms of normal force measurements,the FWMFS can monitor finger pressure and sliding trajectories in response to finger taps,as well as measure plantar pressure for assessing human *** plantar pressure signals of five human movements collected by the FWMFS were analyzed using the k-nearest neighbors classification algorithm,which achieved a recognition accuracy of 92..Additionally,an artificial intelligence biometric authentication system is being developed that classifies and recognizes user *** on the lateral force measurement ability of the FWMFS,the direction of ball movement can be distinguished,and communication systems such as Morse Code can be *** research has significant potential in intelligent sensing and personalized spatial recognition.

关键词： password Morse force

中高温及低温作用后超高韧性水泥基复合材料的力学性能

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复合材料学报 2024年第4期41卷 2014-2030页

作者：钱维民苏骏史庆轩李扬嵇威西安建筑科技大学土木工程学院西安710055 湖北工业大学土木建筑与环境学院武汉430068

为研究超高韧性水泥基复合材料(UHTCC)在2.0~−100℃温度作用后的力学性能,设计了不同纤维体积掺量的UHTCC,经中高温和低温作用后进行基本力学性能试验,通过UHTCC强度和变形等参数评价了中高温和低温作用后UHTCC的力学性能。结果表明:纤... 详细信息

为研究超高韧性水泥基复合材料(UHTCC)在2.0~−100℃温度作用后的力学性能,设计了不同纤维体积掺量的UHTCC,经中高温和低温作用后进行基本力学性能试验,通过UHTCC强度和变形等参数评价了中高温和低温作用后UHTCC的力学性能。结果表明:纤维的掺入能有效改善基体的脆性,提升材料的韧性;同时温度作用导致材料内部出现初始缺陷,对UHTCC的力学性能有明显的影响,且低温作用的影响要明显高于高温作用,当温度降低至−100℃时,UHTCC强度最大降低约75%,变形最大降低约92.,但温度作用未对UHTCC的泊松比产生明显影响。在此基础上提出了中高温及低温作用后UHTCC轴压和轴拉应力-应变关系回归模型,为UHTCC材料在极端温度环境下的性能设计和工程应用提供参考。

关键词：超高韧性水泥基复合材料中高温低温力学性能本构模型