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外科重症监护室医务人员手部接触行为观察与分析 预览
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作者 吴前胜 周雁荣 《护理学杂志》 CSCD 北大核心 2019年第11期54-56,共3页
目的了解ICU医务人员手部与患者及其周围物表接触行为,为加强院感防控工作提供参考。方法将IPad分布于外科ICU不同方位,通过视频拍摄采集医务人员手部与患者及其周围物表接触行为的发生及目的等信息。结果拍摄视频15份,共计19.02h,每份(... 目的了解ICU医务人员手部与患者及其周围物表接触行为,为加强院感防控工作提供参考。方法将IPad分布于外科ICU不同方位,通过视频拍摄采集医务人员手部与患者及其周围物表接触行为的发生及目的等信息。结果拍摄视频15份,共计19.02h,每份(1.27±0.18)h。采集接触行为292人次,平均15.35人次/h。接触总频次463次,其中物表接触286次,发生率61.77%,平均15.03次/h;患者接触177次,发生率38.23%,平均9.31次/h。在各类人员中,护士接触人次最多(150人次),其他依次为助理护士(92人次)、医生(42人次)及其他人员(8人次);非必要接触行为共发生144人次,医生、护士、助理护士及其他人员分别为15人次、85人次、41人次和3人次,各类人群之间必要与非必要接触比例比较,差异有统计学意义(P<0.05)。结论应加强医务人员对接触行为的重视,尽量降低与患者的接触频率,减少医院感染的发生。 展开更多
关键词 外科ICU 医务人员 手部 接触 非必要接触 接触传播 医院感染 手卫生
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Analysis of nickel distribution by synchrotron radiation X-ray fluorescence in nickel-induced early- and late-phase allergic contact dermatitis in Hartley guinea pigs
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作者 Shan-Qun Jiang Xiang-Yu Wu +11 位作者 Jin-Lyu Sun Guang Chen Rui Tang Zhi Li Ruo-Yao Wei Lan Liang Xian-Jie Zhou Dong-Liang Chen Jun Li Hong Gao Jing Zhang Zuo-Tao Zhao 《中华医学杂志:英文版》 SCIE CAS CSCD 2019年第16期1959-1964,共6页
Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process an... Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy. Methods: Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10%(sensitization-challenge;late phase group);10% NiSO4-group, 10% to 10%(sensitization-challenge;early-phase group);and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES). Results: In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (>200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni^2+ aqueous ionic state but in the nickel-binding protein. Conclusions: This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni^2+ aqueous ionic state but 展开更多
关键词 Synchrotron radiation micro X-RAY fluorescence SPECTROSCOPY Micro X-RAY absorption near-edge SPECTROSCOPY Dermatitis ALLERGIC CONTACT Nickel-induced ALLERGIC CONTACT DERMATITIS Dermatology
Modeling and Experiment on Contact Stiffness and Accuracy Analysis of Ball Linear Guide Feed Unit 预览
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作者 Wei Zhang Min Wang Bingbing Le 《哈尔滨工业大学学报:英文版》 EI CAS 2019年第1期30-41,共12页
The contact stiffness and the error analysis have an important effect on the manufacture and the optimization of Ball Linear Guide Feed Unit (BLGFU). In order to analyze the contact stiffness and linear errors or angl... The contact stiffness and the error analysis have an important effect on the manufacture and the optimization of Ball Linear Guide Feed Unit (BLGFU). In order to analyze the contact stiffness and linear errors or angle errors of BLGFU, in this paper, the contact stress and deformation mechanics between the ball and rail is analyzed. Based on Hertz theory of contact and theory of the multi-body system, a model of the contact stiffness considering the changes in contact angle is established. With the increasing of the external load, the varying trend of the contact deformation can be obtained. Therefore, the motion accuracy degradation of the BLGFU can be analyzed. By using a special experimental device and test system of the rolling linear guide worktable, the horizontal contact stiffness and the vertical linear stiffness are obtained, respectively. By comparing the contact stiffness of the experiment dates and the simulation results, the variation tendency of two curves is consisted and the difference between the measured values and the theoretical values is less than 18%. It is obvious that the model of the contact stiffness considering changes of contact angle has accuracy and feasibility. Thus, while external force point locating at different positions;the contact stiffness and the accuracy analysis of the BLGFU are proved validity by simulations. 展开更多
关键词 BALL linear guide FEED UNIT HERTZ CONTACT theory CONTACT STIFFNESS accuracy analysis
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VECTOR FIELDS FOR CONTACT PAIRS 预览
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作者 何跃 赫海龙 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第4期1081-1088,共8页
Let M be a(2 k + 2 l + 2)-dimensional smooth manifold. For such M, Bande and Hadjar introduce a new geometric structure called contact pair which roughly is a couple of 1-forms of constant classes with complementary k... Let M be a(2 k + 2 l + 2)-dimensional smooth manifold. For such M, Bande and Hadjar introduce a new geometric structure called contact pair which roughly is a couple of 1-forms of constant classes with complementary kernels and foliations. We show the relationship between a pair of vector fields for a contact pair and a quadruple of functions on M. This is a generalization of the classical result for contact manifolds. 展开更多
关键词 CONTACT GEOMETRY Reeb VECTOR FIELD CONTACT PAIR
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Microhabitat Segregation of Parapatric Frogs in the Qinling Mountains
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作者 Shengnan YANG Jianping JIANG +4 位作者 Zhenhua LUO Xin YANG Xiaoyi WANG Wenbo LIAO Junhua HU 《亚洲两栖爬行动物研究:英文版》 SCIE CSCD 2019年第1期48-55,共8页
Coexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distributio... Coexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distribution range as well as facilitate partitioning resource utilization in ecological similar species. Understanding niche segregation and differences in microhabitat utilization can contribute to identifying coexistence mechanisms between parapatric species. Feirana quadranus and F. taihangnica are two closely related frog species with parapatric geographic ranges and an elongated contact zone within the Qinling Mountains, which is an important watershed for East Asia. Here, we analysed the difference in microhabitat utilization between the two frog species and explored the key ecological factors that induced their microhabitat differentiation based on quadrats sampled in the contact zone. Our comparison of twenty environmental variables showed that both species used microhabitats with alkalescent warm water and gentle slope conditions. The principal component analysis indicated that climate-related variables, vegetation conditions, and river width were the important factors for microhabitat utilization of these species. These findings contribute to our understanding on the coexistence mechanisms of these two related and parapatric Asian mountain frog species. This study can also be helpful for identifying target habitats to conduct conservation actions and management strategies effectively in the face of environmental changes. 展开更多
关键词 COEXISTENCE contact zone MICROHABITAT utilization NICHE SEGREGATION Feirana QINLING Mountains
Release and uptake mechanisms of vesicular Ca^2+stores
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作者 Junsheng Yang Zhuangzhuang Zhao +2 位作者 Mingxue Gu Xinghua Feng Haoxing Xu 《蛋白质与细胞:英文版》 SCIE CAS CSCD 2019年第1期8-19,共12页
Cells utilize calcium ions(Ca^2+)to signal almost all aspects of cellular life,ranging from cell proliferation to cell death,in a spatially and temporally regulated manner.A key aspect of this regulation is the compar... Cells utilize calcium ions(Ca^2+)to signal almost all aspects of cellular life,ranging from cell proliferation to cell death,in a spatially and temporally regulated manner.A key aspect of this regulation is the compartmen-talization of Ca^2+in various cytoplasmic organelles that act as intracellular Ca^2+stores.Whereas Ca^2+release from the large-volume Ca^2+stores,such as the endoplasmic reticulum(ER)and Golgi apparatus,are preferred for signal transduction,Ca^2+release from the small-volume individual vesicular stores that are dispersed throughout the cell,such as lysosomes,may be more useful in local regulation,such as membrane fusion and individualized vesicular movements.Conceivably,these two types of Ca^2+stores may be established,maintained or refilled via distinct mechanisms.ER stores are refilled through sustained Ca^2+influx at ER-plasma membrane(PM)membrane contact sites(MCSs).In this review,we discuss the release and refilling mechanisms of intracellular small vesicular Ca^2+stores,with a special focus on lysosomes.Recent imaging studies of Ca2+release and organelle MCSs suggest that Ca^2+exchange may occur between two types of stores,such that the small stores acquire Ca^2+from the large stores via ER-vesicle MCSs.Hence vesicular stores like lysosomes may be viewed as secondary Ca^2+stores in the cell. 展开更多
关键词 Ca^2+stores LYSOSOMES vesicles REFILLING ORGANELLE membrane contact sites(MCSs)
Investigation of the performance of a pilot-scale barrel atmospheric plasma system for plasma activation of polymer particles 预览
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作者 Hisham M.Abourayana Peter J.Dobbyn +1 位作者 Pat Whyte Denis P.Dowling 《纳米技术与精密工程(英文)》 CAS CSCD 2019年第1期1-7,共7页
This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles.The polymer particles treated included acrylon... This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles.The polymer particles treated included acrylonitrile butadiene styrene(ABS)and polypropylene(PP).These particles had diameters in the range of 3–5mm.The initial studies were carried out using a laboratory-scale barrel reactor designed to treat polymer particle batch sizes of 20 g.A pilot-scale reactor that could treat 500 g particle batch sizes was then developed to facilitate pre-industrial-scale treatments.The effect of operating pulse density modulation(PDM)in the range 10%– 100%and plasma treatment time on the level of activation of the treated polymers were then investigated.ABS revealed a larger decrease inwater contact angle compared with PP after plasma treatment under the same conditions.The optimal treatment time of ABS(400 g of polymer particles)in the pilot-scale reactorwas 15 min.The plasma-activated polymer particles were used to fabricate dog-bone polymer parts through injection molding.Mechanical testing of the resulting dog-bone polymer parts revealed a 10.5%increase in tensile strength compared with those fabricated using non-activated polymer particles. 展开更多
关键词 Atmospheric pressure PLASMA BARREL PLASMA REACTOR Polymer particles Water contact angle X-ray PHOTOELECTRON spectroscopy Injection MOULDING
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Enhancement of surface wettability via micro-and nanostructures by single point diamond turning 预览
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作者 Nicolás Cabezudo Jining Sun +5 位作者 Behnam Andi Fei Ding Ding Wang Wenlong Chang Xichun Luo Ben B.Xu 《纳米技术与精密工程(英文)》 CAS CSCD 2019年第1期8-14,共7页
Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes.One of the strategies to tune surface wettability is modifying surface topograp... Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes.One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales.In this research,periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability.This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers,including polyvinyl chloride(PVC),polyethylene 1000(PE1000),polypropylene copolymer(PP)and polytetrafluoroethylene(PFTE),which cannot be processed by conventional semiconductor-based manufacturing processes.Materials exhibiting commonwettability properties(θ≈90°)changed to exhibit“superhydrophobic”behavior(θ?150°).Comparedwith the size of the structures,the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability. 展开更多
关键词 Contact angle WETTABILITY Single-point DIAMOND TURNING STRUCTURED surface HYDROPHOBICITY
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一种滚动轴承滚子接触力分布测量新方法 预览
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作者 季晔 张旦闻 《机床与液压》 北大核心 2019年第3期116-120,134共6页
提出了一套基于数字散斑相关法(DSCM)的轴承滚子接触力测量方法,为轴承滚子修形提供了依据。研究了滚子定位及加载系统,设计了一套简单、合理的定位装置;借助MATLAB开发环境,编写了基于DSCM算法的测量软件。为了验证测量系统的有效性,... 提出了一套基于数字散斑相关法(DSCM)的轴承滚子接触力测量方法,为轴承滚子修形提供了依据。研究了滚子定位及加载系统,设计了一套简单、合理的定位装置;借助MATLAB开发环境,编写了基于DSCM算法的测量软件。为了验证测量系统的有效性,对无修形滚子进行了测量,接触应变分布与有限元法计算结果和已掌握的工程经验吻合;选取4个某型号轴承滚子为测量对象,分别进行了不同载荷条件下、同一载荷条件而两次独立加载条件下、含杂质条件下的典型测量,得到了应变分布趋势。试验结果表明:测量系统满足对滚子接触力测量试验要求,系统测量结果具有良好的重复性,微尺度变化会显著影响接触力分布。 展开更多
关键词 轴承滚子 接触 数字散斑相关方法 应变分析
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Plastic Effect on the Sliding Inception Bet ween a Cylinder and a Rigid Flat
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作者 S.Zhang J.Huan +2 位作者 H.Song X.Liu Y.G.Wei 《固体力学学报:英文版》 SCIE EI CSCD 2019年第1期1-16,共16页
The effec ts of mat erial plasticity and local slip on the sliding inception of asperity are studied in the present work.Firstly,a semi-analytical solution is derived under the full-stick condition to analyze the effe... The effec ts of mat erial plasticity and local slip on the sliding inception of asperity are studied in the present work.Firstly,a semi-analytical solution is derived under the full-stick condition to analyze the effect of material plasticity on sliding friction.Then,a friction model with contact stiffness criterion is proposed to study the cases from partial-slip condition to full-stick condition.Finite element simulations with the provided model are used to present the friction map.The friction coefficient of full-s tick interface converges at a st able value,approxima tely 0.3.Plasticity saturation appears as the normalized contact interference u*is larger than 3.A transition mechanism from slip-dominated to yield-dominated takes place in the sliding process.The simulation results are compared with the semi-analytical solution. 展开更多
关键词 Mat erial YIELDING Local SLIP Contact STIFFNESS criterion Finite element simulation
Mechanism of Spine Motion About Contact Time in Quadruped Running
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作者 Qi Liu Yannian Bao +3 位作者 Wei Yu Jianming Zhang Chao Li Xinru Xie 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期53-60,共8页
The current research of quadruped robot focuses on the quadruped robot with spine motion. Contact time is a very important part of system performance. However, the mechanism of spine motion about contact time has not ... The current research of quadruped robot focuses on the quadruped robot with spine motion. Contact time is a very important part of system performance. However, the mechanism of spine motion about contact time has not been clearly elucidated. In this paper, the e ect of spine motion on contact time is studied deeply from dynamic view.Firstly, a simplified model of the quadruped robot with spine joint is set up, its dynamic equations are derivated, and a method that can generate passive periodic locomotion is proposed. Secondly, according to the vertical spring oscillator model, the two-dimension planar locomotion of the simplified model is regarded as a special vibration in the vertical direction, and the approximate formula of calculating contact time is obtained. Finally, the approximate formula of calculating contact time is verified by the simulation results of passive periodic locomotion, and the e ect of spine motion on contact time is deeply discussed based on the approximate formula of calculating contact time. The discussion proves that spine motion indeed has little e ect on contact time, but spine motion can slightly reduce body pith movement and regulate the leg sti ness in leg contact phase. This research proposes an e ective research method which can be used to study the motion mechanism of the quadruped robot with spine motion,and the mechanism of spine motion about contact time is clearly elucidated which is helpful to set the parameters of mechanical structure and study control algorithm about the quadruped robot with spine motion. 展开更多
关键词 QUADRUPED robot SPINE MOTION PASSIVE locomotion Contact time LEG STI ness
金属环尺寸对重力式扩展风机基础影响研究 预览
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作者 张林杰 张翼虎 梁培新 《江苏建筑》 2019年第2期88-91,共4页
文章应用相关力学知识和接触理论,分析了风机基础中金属环与混凝土的相互作用。以某风电基础设计为背景,利用Ansys软件建立了风机基础的有限元模型,研究了关键部位金属环端部对风机基础力学性能的影响。结论表明,适当的环端高度和埋深... 文章应用相关力学知识和接触理论,分析了风机基础中金属环与混凝土的相互作用。以某风电基础设计为背景,利用Ansys软件建立了风机基础的有限元模型,研究了关键部位金属环端部对风机基础力学性能的影响。结论表明,适当的环端高度和埋深比对基础起有利作用,为风机基础金属环结构设计提供了科学的优化意见。 展开更多
关键词 风机基础 金属环 接触 埋深比
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Impacts of Wettability on Immiscible Fluid Flow Pattern-Microfluidic Chip Experiment 预览
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作者 Zheng Xianglei Jang Jaewon 《中国炼油与石油化工:英文版》 SCIE CAS 2019年第1期80-89,共10页
Immiscible fluid flow is frequently found in resource recovery or soil remediation. The flow pattern in the porous media is affected by the wettability of pore surface. In this study, quartz substrates and microfluidi... Immiscible fluid flow is frequently found in resource recovery or soil remediation. The flow pattern in the porous media is affected by the wettability of pore surface. In this study, quartz substrates and microfluidic chips are treated by silica nanoparticles(SNP) and triethoxy(octyl)silane(TES) to fabricate the water-wet and oil-wet surfaces. The wettability of the treated-surface is measured in term of contact angle for several combinations of surrounding fluid and a liquid droplet. The effect of the wettability on the fluid flow pattern is explored by injecting oil and water alternately into the surface-treated microfluidic chips. The results reveal that the SNP-coated quartz substrate shows strong water-wet property and the TES coating makes water-repellent/oil-wet surfaces. In addition, it is found that the maximum and minimum oil and water saturation during alternate injection of oil and water depends on the surface wettability of the microfluidic chips. The characteristics of the pore-scale fluid flow pattern are also described. 展开更多
关键词 WETTABILITY contact angle nanoparticle coating HYDROPHILIC HYDROPHOBIC microfluidic chip
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Heuristic Computing Methods for Contact Plan Design in the Spatial-Node-Based Internet of Everything 预览
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作者 Cuiqin Dai Qingyang Song 《中国通信:英文版》 SCIE CSCD 2019年第3期53-68,共16页
To satisfy the increasing demands of high-speed transmission,high-efficiency computing,and real-time communications in the high-dynamic and heterogeneous networks,the Contact Plan Design(CPD)has attracted continuous a... To satisfy the increasing demands of high-speed transmission,high-efficiency computing,and real-time communications in the high-dynamic and heterogeneous networks,the Contact Plan Design(CPD)has attracted continuous attention in recent years,especially for the spatial-node-based Internet of Everything(IoE).In this paper,we study the NP-hardness of contact scheduling and the attenuation of atmospheric precipitation in the spatial-node-based IoE.Two heuristic computing methods for contact plan design are proposed by comprehensively considering the time-varying topology,the intermittent connectivity,and the adaptive transmission in different weather conditions,which are named Contact Plan Design-Particle Swarm Optimization(CPD-PSO)and Contact Plan Design-Greedy algorithm with the Minimum Delivery Time(CPD-GMDT)separately.For the population-based algorithm,CPD-PSO not only solves the CPD problem with a limited-resource condition,but also dynamically adjusts the search scope to ensure the continuous searching capability of the algorithm.For the CPD-GMDT that makes CP decisions based on the current state,the algorithm uses the idea of greedy algorithm to schedule Satellite-Platform Links(SPLs)and Inter Satellite Links(ISLs)respectively using the strategies of optimal matching and load balancing.The simulation results show that the proposed CPD-PSO outperforms Contact Plan Design-Genetic Algorithm(CPD-GA)in terms of fitness and delivery time,and CPD-GMDT presents better overall delay than Fair Contact Plan(FCP). 展开更多
关键词 INTERNET of Everything HEURISTIC computing CONTACT plan design particle SWARM optimization GREEDY algorithms
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Pressure-mediated contact quality improvement between monolayer MoS2 and graphite
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作者 廖梦舟 杜罗军 +5 位作者 张婷婷 谷林 姚裕贵 杨蓉 时东霞 张广宇 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期178-182,共5页
Two-dimensional(2D) materials and their heterostructures have attracted a lot of attention due to their unique electronic and optical properties. MoS2 as the most typical 2D semiconductors has great application potent... Two-dimensional(2D) materials and their heterostructures have attracted a lot of attention due to their unique electronic and optical properties. MoS2 as the most typical 2D semiconductors has great application potential in thin film transistors, photodetector, hydrogen evolution reaction, memory device, etc. However, the performance of MoS2 devices is limited by the contact resistance and the improvement of its contact quality is important. In this work, we report the experimental investigation of pressure-enhanced contact quality between monolayer MoS2 and graphite by conductive atom force microscope(C-AFM). It was found that at high pressure, the contact quality between graphite and MoS2 is significantly improved. This pressure-mediated contact quality improvement between MoS2 and graphite comes from the enhanced charge transfer between MoS2 and graphite when MoS2 is stretched. Our results provide a new way to enhance the contact quality between MoS2 and graphite for further applications. 展开更多
关键词 MoS2/graphite HETEROJUNCTION C-AFM PRESSURE CONTACT quality
Mathematical Model of Drag Torque with Surface Tension in Single-Plate Wet Clutch
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作者 Zengxiong Peng Shihua Yuan 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期93-99,共7页
Reduction of drag torque in disengaged wet clutches is essential for transmission research because it is one of the potentials of e ciency improvement. Aeration of oil film between two closely rotating plates promotes... Reduction of drag torque in disengaged wet clutches is essential for transmission research because it is one of the potentials of e ciency improvement. Aeration of oil film between two closely rotating plates promotes the decrease of drag torque at high speed region. The e ects of surface tension and static contact angles during aeration are nonnegligible showed by test results. The traditional lubrication model does not adequately predict the experimental results with di erent surface tension and contact angles during aeration. Hence, in this present paper, contact angles between Aluminum and Teflon materials were firstly measured, and the drag torques under two di erent contact angles were examined experimentally. An improved lubrication model of drag torque based on Navier–Stokes equations at the gas-liquid interface was built. The lubrication boundary condition was modified to introduce the e ects of surface tension and contact angle. The model shows that the e ects at the beginning of aeration of oil film are significant. These e ects almost occur at stationary plate due to low Reynolds number and Weber number. The model shows that an increase in the surface tension promotes aeration, but does not a ect the peak drag torque. Increasing contact angle also promotes the aeration, and accelerates the decrease of drag torque. The larger contact angle is, the smaller the peak drag torque will be. A computational fluid dynamics(CFD) model based on volume of fluid(VOF) method was presented to validate the interface shape when aeration occurs. The model prediction has a good agreement with experimental observations for Aluminum plates and Teflon plates. The modified lubrication model of drag torque gives a convenient description of the e ects of surface tension and contact angel, and lays down a frame to understand the beginning of aeration. 展开更多
关键词 Drag TORQUE WET CLUTCH Surface tension Contact ANGLE
Use of improved cold-finger technique to assess effects of basicity on heat transfer through solidified mold flux
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作者 Karina Lara Santos Assis Petrus Christiaan Pistorius 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第4期393-402,共10页
Cold-finger measurements were used to estimate the contact resistance and average thermal conductivity of mold flux films solidified on a water-cooled copper probe.Five industrial mold fluxes,with basicities from low ... Cold-finger measurements were used to estimate the contact resistance and average thermal conductivity of mold flux films solidified on a water-cooled copper probe.Five industrial mold fluxes,with basicities from low to high,were tested.The steady-state rate of convective heat transfer between the solid film and liquid flux was compared with calculations based on natural convection correlations;the comparison indicates that the surface of the solid film(in contact with molten flux)is approximately at its solidus temperature.The roughness of the mold flux film in contact with copper was larger for films grown from higher-temperature mold flux and for higher-basicity mold fluxes.The glassy(low-basicity)film had an estimated thermal conductivity of 1.1 W/(m K).The crystalline or partially crystalline films had higher estimated thermal conductivities of 2.2-3.2 W/(m K).The measured values of thermal resistance were extrapolated to typical mold flux film thicknesses for industrial conditions;the extrapolations confirmed that the high contact resistance of higher-basicity mold fluxes can yield higher thermal resistances than the low-basicity flux.The morphology of the rough interface of higherbasicity mold flux films that gives the higher contact resistance is consistent with that observed in previous work and appears not to be directly related to crystallization. 展开更多
关键词 MOLD flux Heat transfer Conduction Contact resistance-Cold-finger TECHNIQUE
全海深载人潜水器厚观察窗结构的强度研究 预览
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作者 杜青海 高睿 崔维成 《中国造船》 EI CSCD 北大核心 2019年第2期1-12,共12页
全海深载人潜水器是当前海洋技术领域最有挑战性的深海装备之一,而锥台型观察窗的设计是全海深载人潜水器的技术难点.为了研究锥台型观察窗的结构参数和倒角对于应力和位移的影响,首先利用ABAQUS对文献记述的试验进行仿真,验证有限元模... 全海深载人潜水器是当前海洋技术领域最有挑战性的深海装备之一,而锥台型观察窗的设计是全海深载人潜水器的技术难点.为了研究锥台型观察窗的结构参数和倒角对于应力和位移的影响,首先利用ABAQUS对文献记述的试验进行仿真,验证有限元模型的可靠性.然后建立带有两种边界条件的有限元模型,对比分析位移和应力的差异.最后研究锥角α、厚度直径比t/Di、摩擦系数μ和倒角对锥台型观察窗的位移和应力的影响.数值分析结果表明:有限元仿真数据比文献试验数据稍大,偏保守;自由边界时的轴向位移比固定边界时的大,更符合实际工程应用;3个设计参数与应力和位移均成反比,给出了锥角和厚度直径比的合理优化区间;在锥台型观察窗内侧面边缘处建立倒角有利于减小应力集中. 展开更多
关键词 HOV 锥台型观察窗 有限元分析 接触
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Patterning catalyst via inkjet printing to grow single-walled carbon nanotubes
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作者 Zeyao Zhang Yitan Li +6 位作者 Sheng Zhu Xiyan Liu Xiulan Zhao Meihui Li Haoyu Li Feng Yang Yan Li 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第2期505-508,共4页
Controlled growth of patterned single-walled carbon nanotubes (SWNTs) is an important issue in many applications. Herein, we demonstrated a method to pattern catalyst via inkjet printing for the growth of SWNTs, using... Controlled growth of patterned single-walled carbon nanotubes (SWNTs) is an important issue in many applications. Herein, we demonstrated a method to pattern catalyst via inkjet printing for the growth of SWNTs, using metal salt solutions as the inks and an ordinary office-use printer. We printed water solutions of cobalt acetate on hydrophilic Si substrates and grew high quality SWNT films. The composition of the precursor solutions and the hydrophilicity of the substrates were crucial factors to the patterning. 展开更多
关键词 SINGLE-WALLED carbon NANOTUBES INKJET printing PATTERNING Contact angle Chemical vapor deposition
关于梁与刚体接触问题的讨论 预览
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作者 吴晓 《工程与试验》 2019年第1期9-10,共2页
讨论了梁与刚体接触的问题,推导出了悬臂梁与刚体接触的压力公式。研究结果表明,梁与刚体接触问题本质上是非线性问题。计算梁自由端的挠度时,可以对非线性项进行线性简化;计算梁与刚体接触处之间梁段接触压力时,对非线性项进行线性简... 讨论了梁与刚体接触的问题,推导出了悬臂梁与刚体接触的压力公式。研究结果表明,梁与刚体接触问题本质上是非线性问题。计算梁自由端的挠度时,可以对非线性项进行线性简化;计算梁与刚体接触处之间梁段接触压力时,对非线性项进行线性简化是不合适的。 展开更多
关键词 接触 压力 非线性
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