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Atomic switches of metallic point contacts by plasmonic heating

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Light(Science & Applications) 2019年第1期8卷 893-900页

作者： Weiqiang Zhang Hongshuang Liu Jinsheng Lu lifa ni Haitao Liu Qiang Li Min Qiu Bingqian Xu Takhee Lee Zhikai Zhao Xianghui Wang Maoning Wang Tao Wang Andreas Offenhausser Dirk Mayer Wang-Taek Hwang Dong Xiang Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Key Laboratory of Optical Information Science and TechnologyInstitute of Modern OpticsCollege of Electronic Information and Optical EngineeringNankai University300350 TianjinChina State Key Laboratory of Modern Optical Instrumentation College of Optical Science and EngineeringZhejiang University310027 HangzhouChina College of Engineering University of GeorgiaAthensGA 30602USA Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul 08826Korea Institute of Materials Research and Engineering A*STAR2 Fusionopolis WayInnovisSingapore 138634Singapore Institute of Complex Systems ICS-8BioelectronicsResearch Center Juelich and JARA Fundamentals of Future Information TechnologyJülich 52425Germany

Electronic switches with nanoscale dimensions satisfy an urgent demand for further device miniaturization.A recent heavily investigated approach for nanoswitches is the use of molecular junctions that employ photochromic molecules that toggle between two distinct *** contrast to the reports on this approach,we demonstrate that the conductance switch behavior can be realized with only a bare metallic contact without any molecules under light *** demonstrate that the conductance of bare metallic quantum contacts can be reversibly switched over eight orders of magnitude,which substantially exceeds the performance of molecular *** the switch process,the gap size between two electrodes can be precisely adjusted with subangstrom accuracy by controlling the light intensity or *** by simulations,we reveal a more general and straightforward mechanism for nanoswitching behavior,i.e.,atomic switches can be realized by the expansion of nanoelectrodes due to plasmonic heating.

关键词： metallic behavior illumination

High efficiency of heavy metal removal in mine water by limestone

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Chinese Journal Of Geochemistry 2009年第3期28卷 293-298页

作者： YAO Zhigang ZHOU lifa BAO Zhengyu GAO Pu SUN Xingwang Key Laboratory of Continental Dynamics Ministry of Education/Department of Geology Northwest University Xi＇an 710069 China School of Petroleum Resources Xi＇an Shiyou University Xi＇an 710065 China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China Chuankou Oilfield Yanchang OilfieldAdministration Bureau Shaanxi Yan＇an 768001 China

The removal of Cd, Cu, ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.

关键词：重金属石灰石高效率矿水地质资料砾状灰岩实验室规模去除率

A thermal conductivity switch via the reversible 2H–1T′phase transition in monolayer MoTe_(2)

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Chinese Physics B 2023年第5期32卷 1-6页

作者：张定波任卫君王珂陈帅张力发倪宇翔张刚 School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031China Institute of High Performance Computing A*STAR 138632Singapore Center for Phononics and Thermal Energy Science China-EU Joint Laboratory for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China School of Automation Xi’an University of Posts and TelecommunicationsShaanxi 710121China NNU-SULI Thermal Energy Research Center and Center for Quantum Transport and Thermal Energy Science(CQTES)School of Physics and TechnologyNanjing Normal UniversityNanjing 210023China

The two-dimensional(2D)material-based thermal switch is attracting attention due to its novel applications,such as energy conversion and thermal management,in nanoscale *** this paper,we observed that the reversible 2H–1T′phase transition in MoTe_(2)is associated with about a fourfold/tenfold change in thermal conductivity along the X/Y direction by using first-principles *** phenomenon can be profoundly understood by comparing the Mo–Te bonding strength between the two *** 2H-MoTe_(2)has one stronger bonding type,while 1T′-MoTe_(2)has three weaker types of bonds,suggesting bonding inhomogeneity in 1T′-MoTe_(2).Meanwhile,the bonding inhomogeneity can induce more scattering of vibration *** weaker bonding indicates a softer structure,resulting in lower phonon group velocity,a shorter phonon relaxation lifetime and larger Gr¨uneisen *** impact caused by the 2H to 1T′phase transition in MoTe_(2)hinders the propagation of phonons,thereby reducing thermal *** study describes the possibility for the provision of the MoTe_(2)-based controllable and reversible thermal switch device.

关键词： thermal switch MoTe_(2) phase transition thermal conductivity mechanism

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电容脉冲焊补设备参数的仿真优化研究

热加工工艺 2021年第3期50卷 137-140,144页

作者：封礼发阳能军袁晓静姚春江火箭军工程大学304教研室陕西西安710038

推导了电阻点焊中接触电阻的计算模型,结合COMSOL仿真软件模拟了电容脉冲焊补设备对厚度为0.2mm 1Cr18ni9Ti不锈钢的点焊。分析了不同电极压力下对应的熔核及设备参数,得到在该厚度下不锈钢最佳的焊补电极压力为50 N,分析了不同电压下... 详细信息

推导了电阻点焊中接触电阻的计算模型,结合COMSOL仿真软件模拟了电容脉冲焊补设备对厚度为0.2mm 1Cr18ni9Ti不锈钢的点焊。分析了不同电极压力下对应的熔核及设备参数,得到在该厚度下不锈钢最佳的焊补电极压力为50 N,分析了不同电压下对应的熔极及设备参数,得到该厚度不锈钢的焊补电压为10 V,放电压差为3 V。模拟了上述参数下熔核边缘温度的冷却过程,得到的冷却时间为15 ms,对应放电控制开关的频率范围为1~65 Hz。

关键词：接触电阻脉冲焊补仿真 COMSOL

基于多线程的VSAT卫星通信系统的网控中心的设计与实现

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通信学报 1998年第11期19卷 92-96页

作者：倪桂强吴礼发胡谷雨谢希仁通信工程学院计算机教研室

网控中心（ＮｅｔｗｏｒｋＣｏｎｔｒｏｌＣｅｎｔｅｒ）是ＶＳＡＴ卫星通信系统的核心。本文讨论网控中心的设计与实现。论文首先简要介绍了一种容错的网控中心结构模型，该模型采用的主要策略是冗余备份。然后，进一步讨论了网控中心... 详细信息

网控中心（ＮｅｔｗｏｒｋＣｏｎｔｒｏｌＣｅｎｔｅｒ）是ＶＳＡＴ卫星通信系统的核心。本文讨论网控中心的设计与实现。论文首先简要介绍了一种容错的网控中心结构模型，该模型采用的主要策略是冗余备份。然后，进一步讨论了网控中心的可靠性设计。最后，介绍了一种基于多线程的网控中心的实现。通过利用多线程和多级容错措施等方法，我们实现的网控中心具有可靠性好，高性能，容易使用等特点。

关键词： VSAT 网控中心可靠性卫星通信系统

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电磁超声横波换能器中线圈的优化设计

应用声学 2019年第3期38卷 428-433页

作者：阳能军封礼发唐旭明张宪宇姚春江火箭军工程大学304教研室

为改善电磁超声换能器在1Cr18ni9Ti不锈钢材料中激发横波的特性,提出一种基于正交试验的优化方法,并利用有限元仿真软件 COMSOL Multiphysics建立了电磁超声横波换能器的有限元模型,应用正交试验和极差分析法,分析了线圈各参数对电磁超... 详细信息

为改善电磁超声换能器在1Cr18ni9Ti不锈钢材料中激发横波的特性,提出一种基于正交试验的优化方法,并利用有限元仿真软件 COMSOL Multiphysics建立了电磁超声横波换能器的有限元模型,应用正交试验和极差分析法,分析了线圈各参数对电磁超声横波的近场长度和半扩散角的影响,比较了线圈各参数影响程度的大小。结果表明,激励电流的频率和线圈的尺寸对横波的传播特性有着明显影响,提高频率会使得横波的近场长度增大及半扩散角减小;其次,减小导线的宽度及间距,以缩小线圈尺寸能有效改善横波的传播特性。

关键词：电磁超声横波换能器线圈有限元模型

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基于COMSOL的电容储能焊补仿真研究

热加工工艺 2021年第5期50卷 155-159页

作者：封礼发阳能军姚春江袁晓静王旭平火箭军工程大学304教研室陕西西安710038

结合COMSOL软件中的薄层阻抗接口,采用提出的接触电阻计算模型模拟了焊补设备对1Cr18ni9Ti不锈钢的电容储能点焊过程,得到的焊点熔核半径为148.9μm,基体部位熔核高15.5μm,该结果与实测得到的熔核半径153μm、基体熔核高16.6μm相差较... 详细信息

结合COMSOL软件中的薄层阻抗接口,采用提出的接触电阻计算模型模拟了焊补设备对1Cr18ni9Ti不锈钢的电容储能点焊过程,得到的焊点熔核半径为148.9μm,基体部位熔核高15.5μm,该结果与实测得到的熔核半径153μm、基体熔核高16.6μm相差较小,证明了仿真方法的正确性。分析了动态电阻和接触电阻率的变化。动态电阻的变化因电容储能电源的放电特性可分为三个不同阶段。对于接触电阻率,在电极/补层接触区域熔核半径119μm处会发生突变,表现为绝缘,在熔核区域则因熔点温度下屈服强度较小导致接触电阻率变化不明显。研究了动态电阻对模拟结果的影响,发现若不考虑动态电阻对电容放电的影响,熔核尺寸明显减小,得出了在电容储能电源仿真中不能因时间较短就将动态电阻设为定值的结论。本研究可为接触电阻的处理提供一种解决办法,对电容储能焊补设备的仿真提供借鉴。

关键词：点焊接触电阻仿真电容储能焊补

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北京采矿废弃地植物修复重金属去除率研究

城市地质 2016年第4期11卷 7-14页

作者：孙楠闫广新王立发张言邢宇鑫王金艳北京市地质工程设计研究院北京101500 芬兰阿尔托大学赫尔辛基fi00076 北京科技大学北京100083

结合北京市采矿废弃地土壤地质环境情况,选取密云区西坨古金矿尾矿土、密云区冯家峪铁矿尾矿土和门头沟区桑峪煤矸石堆为研究对象,进行植物修复研究。共开展4种类型的修复试验,即选用高羊茅、紫花苜蓿和三叶草3种修复植物分别进行修复,... 详细信息

结合北京市采矿废弃地土壤地质环境情况,选取密云区西坨古金矿尾矿土、密云区冯家峪铁矿尾矿土和门头沟区桑峪煤矸石堆为研究对象,进行植物修复研究。共开展4种类型的修复试验,即选用高羊茅、紫花苜蓿和三叶草3种修复植物分别进行修复,同时与板蓝根、桔梗、波斯菊和薄荷等中草药进行混合种植修复,在植物生命周期的不同阶段采集样品分析测试。结果表明:在4种修复类型中,高羊茅对金矿尾矿土中Pb、Zn、Cr、Cd去除效果最好,最大去除率达到18.10%、14.57%、13.81%、18.12%;混合种植对铁矿尾矿土中Cr、ni、As、Hg去除率达到4种修复类型的最大值,分别为14.81%、9.80%、37.25%、50%。三叶草对煤矸石修复效果最好,对Cr、Pb、Zn、Cd的去除率分别为5.65%、37.15%、15.15%、20%,是4种修复模式去除率的最大值。在生命周期的不同阶段,对比4种修复模式对采矿废弃地土壤中8种重金属的去除效果,均发现有去除率先升后降的现象,因此可对修复植物的进行定期收割,为提高植物吸附土壤重金属的效率,提供一定科学依据。

关键词：采矿废弃地植物修复去除率修复模式生命周期