微摩擦测试的微力传感器设计

论述了一种新的应用于微摩擦测试的微力传感器,这种微力传感器能同时测定微小摩擦力及相应正压力的大小,其独特的悬臂结构消除了多维力传感器普遍关注的耦合问题．正压力和摩擦力的测力原理分别基于应变片法和位移法．标定及静态特性的分析表明,该微力传感器具有较高的测力精度和分辨力,适合于mN级的摩擦测试．摩擦测试实验表明,该微力传感器完全能进行各种润滑膜的微摩擦性能评估测试,从而为微摩擦研究提供了一种有效的实验工具．     

现代机床设计中液压泵及电动机的选择方法

<正>现代机床的组成系统大致分为机械系统、液压系统、电气系统。其中液压泵及电动机分别是液压系统、电气系统的主要组成元件,二者的选择至关重要。选择液压泵时要满足主机工况、功率大小和系统对工作性能的要求;电动机的选择必须符合节能要求,考虑运行可靠性。1液压泵的选择液压泵是向液压系统提供一定流量和压力油液的动力元件,它是每个液压系统不可缺少的核心元件,合理的选择液压泵     

甲壳糖—聚硅氧烷复合材料的制备,表生和性能研究

利用亲，疏水性不同的甲壳糖和聚奎氧烷，通过共混，交联制备出复合膜材。该材料记下抗张强度最高达１３．３ＭＰａ，此时断裂伸长经为９８％，ＤＳＣ分析结果表明在－４０℃至１９０℃之间热稳定性好。结构形态测试证实该材料具有微相分离结构，微区大小在２μｍ－２０μｍ之间。     

螺旋吸气式增氧机的结构设计

根据旋转体在水中高速旋转时形成的负压，吸入空气，在涡流剪切力作用下，产生微小气泡，组成气水混合体的原理，选型设计了螺旋吸气式增氧机。其主要结构由螺旋器，扩散器，空心轴，电动机等部件组成。其设计技术参数为：增氧动力效率０．６１ｋｇ／ｋｗ．ｈ；混合速度７００ｍ＾２ｍ／ｋｗ．ｈ；吸气量３０ｍ＾３／ｈ；工作噪音６０ｄＢ；电机功率０．７５－２．２ｋｗ；单机负荷水面５３０－１６６６．７ｍ＾２。经生产单位试用，     

毫米级微型机器人提高输出力矩和定位精度的方法

为提高毫米级全方位微机器人的输出力矩和定位精度，提高其个体能力，利用虚拟绕组的概念，通过提高微机器人驱动器——电磁型微电动机的高输出力矩和定位精度，克服微型电动机加工工艺的限制性，实现微型机器人的高精度定位。结果表明，微机器人在结构不变的前提下，功能得到改善，进一步拓展了其应用领域。     

一种新型基于热力学法的水泵效率数学模型及应用研究

泵进出口微小温差的测量是热力学法测试水泵效率的关键所在.提出了一种新型的基于热力学法、可简便、精确测试水泵效率的数学模型.该模型通过用水泵进出口压力与压差模拟进出口温差的方法,有效解决了微温差测量的难题,从而使测试系统更简单、测试结果更可靠.实践证明该模型精度完全满足工程实践需要,是推广应用热力学法测试水泵效率的有效途径.     

变频感应电动机测试系统的研究

描述了变频器－电动机测试系统的数学模型,对基于数字滤波的软件同步采样法进行了改进。在微机、高速采样卡、虚拟仪器软件构成的平台上,实现了对变频器供电的电动机的测试,通过修改软件,可满足不同的测试需要。在测量传输功率较大的变频电动机的功率时,采用了损耗总和法进行计算。所研究的测试系统获得了满意的精度要求。     

微小型电动无人机动力系统试验台的设计与实现

本文针对某型微小型无人机的动力系统设计了一套自动测试系统。该系统通过调节遥控器油门大小控制电机的实际输出功率,实时记录和测量电动机的扭矩、拉力、电压、电流和转速等信号,完成动力系统各功能部件的特性试验。经过实际的测试,本试验系统达到设计要求,对于微小型无人机动力系统的研究具有一定的工程应用价值。     

可用于呼吸监测的刺绣型压力传感器的研制

采用刺绣的方法制备压力传感装置,根据呼吸时皮肤扩张产生的压力大小监测人体静止状态下的呼吸状况.基于接触电阻压力感应原理,通过增加接触点的数目,提高接触电阻的灵敏度.在接触点处涂覆硅胶,以减少信号的偏移,提高信号的重复性.最后通过实验验证了该传感器能够感应微小压力的变化.将所制传感器附着于弹性腰带中,能够实现对人体呼吸率的测量.     

温度变化对压力表检测失准的影响

介绍了弹簧管式一般压力表分别在环境温度与检定温度下,温度变化对其的影响。压力表的工作原理是:基于能够产生弹性变形的元件,在其受到压力的作用下产生变形,通过计量变形的程度来测量压力。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has