豚鼠耳蜗基底膜的振动特性

为探讨豚鼠耳蜗基底膜的听觉机制,利用多普勒激光测振技术进行了声音在28只成年健康豚鼠耳中传递的测试实验.将豚鼠麻醉后切断头取出听泡,采用电钻暴露其耳蜗基底膜,利用多普勒激光测振仪在给定的声压级、频率的纯音激励条件下测量豚鼠外耳道耳蜗基底膜的振动速度,并测量了中耳镫骨的振动速度.结果表明,豚鼠外耳道基底膜具有频率选择特性,而且其基底膜的振动具有行波特性.     

基于激光自混合干涉法的微振动测量

激光自混合干涉法由于其测量精度高、光路简单、准直性好等优点,十分适合于微小振动的测量.然而在测量微振动时,由于被测目标振幅微小且大多情况下其表面反射系数很低,造成测量信号的幅值较小以及光反馈导致的信号波形倾斜不明显,给测量信号解调带来了很大难度.在自混合干涉光路中添加一个预反馈镜,构成带预反馈的干涉光路系统,可将测量信号增强2~4倍.同时,推导"基频-极值点判定算法"的频率幅值解调公式,建立了模型算法,实现自混合干涉信号的解调.理论分析和实验表明,频率测量的误差小于2.5%,振幅测量的误差小于5%.      

高频振动外差激光干涉仪研究

光外差激光干涉测量技术具有非接触、超高灵敏度的优点,用于微小振动的测量有独特的优势。采用外差激光干涉技术,结合正交正弦逼近法,在国家高频基准振动台上实现了纳米级的振动位移和相位测量。     

平直条带流致振动特性实验及其数值模拟研究

核反应堆内燃料组件受到高流速冷却剂的冲刷会产生流致振动现象,而燃料棒包壳和格架条带的振动将会导致燃料组件受到磨损,从而影响核电厂运行的安全性.为了研究格架条带流致振动的特性及分析方法,采用不带结构的不锈钢平直条带进行流致振动实验,并使用激光多普勒测振仪测量其在水流动条件下的振动特性.实验结果表明:当涡激振动频率在接近固有频率时会发生"锁定"现象;在特定流速区间内,涡激振动频率与流速呈线性关系;通过湿模态模拟方法可以较好地预测平直条带在水中的固有频率.     

用激光李萨如图形测量振动物体频率及 能量衰减规律

介绍了李萨如图形的形成原理,利用激光李萨如图形测量出振动物体的频率,并作出振动能量衰减规律曲线.     

基于激光自混合散斑干涉的微小流量检测

为实现对激光自混合散斑干涉的微小流量的检测,提出了一种基于激光自混合散斑干涉检测方法。 通过检测得到自混合散斑干涉信号,并对信号进行频谱分析得到流体的平均频率,利用平均频率与流速的拟合 直线进一步获得流量与平均频率的关系,从而精确求解流体微小流量。理论分析和实验表明,该方法可以简单 高效测量微小流量,测量相对误差小于1． 13%。     

应用激光多普勒测振仪的岩块体累计损伤评价试验研究

岩块体崩塌破坏的突发性使其成为最难预防的地质灾害,严重威胁人类的生命财产安全.边坡岩块体崩塌破坏多是系统不稳定导致的动力破坏,而用振动特征参数来进行安全监测和损伤评价更为有效.本文应用激光多普勒测振技术,通过固有振动频率对危岩块体主控结构面的黏结力损伤进行定量分析.通过改进后的极限平衡模型,得出结构面不断劣化块体的安全系数由原来的1.17下降到1.04,与实际破坏结果相符.试验结果表明:固有振动频率一方面可对危岩块体累积损伤进行有效识别,另一方面可以为黏结力参数的合理确定提供客观的数据支持.因此,基于固有振动频率分析的激光多普勒测振技术可实现边坡岩块体的累计损伤评价,并将在未来的工程应用中发挥巨大的作用.     

微结构振动特性的自由衰减测试方法

为准确快速地对微结构的谐振频率和阻尼比进行测试和分析，组建了以激光多普勒测振仪为核心的微结构瞬态离面运动特性测试系统．附有压电驱动的微悬臂梁和微振动薄膜在斜波脉冲激励信号作用下产生自由衰减振动，通过激光多普勒测振仪将瞬态运动速度转换为模拟信号，经数据采集卡数字化后送入计算机，对其振动特性进行分析．实验测得MPA-41200-10型微悬臂梁谐振频率为48．676kHz，阻尼比为0．0029，微薄膜谐振频率为25．446kHz，阻尼比为0．042．实验结果与采用频率扫描方法测试的结果进行了对比，证实自由衰减振动法对微结构振动特性的快速测试是可行、有效的．     

光栅多普勒效应新型地震检波器

传统地震检波器为“永磁-动圈”式电磁检波器，在信号捡取过程中易受电磁干扰，存在非线性、动态范围小等问题．提出一种基于激光光栅多普勒效应的全新地震检波方法，依据谐波特性分析信号频谱，消除了光电接收器和电路噪声、环境波动等因素的影响，由差拍信号转折点的电压得到小于计数当量值的振幅值．实现了频率范围0．8Hz～500Hz，振幅20nm～2．0mm，相对误差小于1％，其动态范围大于100dB．光栅多普勒地震检波器的信号质量好，消除了光源、运动速度及接收器之间的角度影响，提高了微小振动位移的测量精度、分辨率和动态范围。     

测量爆炸冲击过程多普勒信号拾取技术

采用优化后的外差式纵向激光多普勒进行了光路测量,利用短时傅里叶变换最大主值频率法和小波变换模极大值法分析处理多普勒信号,有效地抑制了爆炸信号的噪声.系统测量距离4.5 m,测量速度范围-10 m/s~20 m/s,相对误差小于100/.试验证明,该方法能有效地拾取反映爆炸过程动态特性的多普勒信号,实现对爆炸容器高速动态形变参数的精确测量.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

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~~