硅四端型膜片式压力传感器的优化设计与分析

本文从理论上分析了硅剪切压阻系数的择优取向,以及在矩形、方形和圆形弹性膜片上欲获得较大剪应力,电阻条的布局原则。利用本文提供的方法,对某些膜片上的四端应变电阻所进行的布局分析与Kanda用有限差分法计算出来的布局结果基本一致。文中还提出了膜片上一些新的布局,供设计者选用。     

热激励谐振式硅微结构压力传感器

针对一种以矩形硅膜片为一次敏感元件、硅梁谐振子为二次敏感元件采用电阻热激励、压敏电阻拾振的谐振式压力微传感器 ,简述了其工作机理 ;从谐振式硅微传感器整体优化设计、闭环系统优化设计、微弱信号检测、敏感元件工艺实践、开环特性测试等方面介绍了该传感器研究与研制过程中近期取得的阶段性研究结果     

计算机辅助硅膜片的应变与应力分析

膜片式半导体压力传感器是一种以形变引起硅材料电阻率发生变化为原理而制成的器件,因此正确认识硅弹性形变膜片上的应力和应变分布情况是合理布局应变电阻条的前提。根据硅的晶体结构并利用各向异性腐蚀剂,可以较方便地获得周边固定的矩形和方形形变膜片。本文用计算机模拟出应变和应力在这些膜面上的变化规律。     

硅压力传感器基座受力变形时的输出性能

为分析硅压力传感器基座受力变形对传感器输出性能的影响,首先利用弹性力学理论和板壳理论分析推导了压力传感器方形膜片应力分布,为力敏电阻在应变膜上的布置提供依据;再利用ANSYS进行分析模拟,探究了传感器基座结构变形对应变膜应力差的影响;然后针对减小基座受力变形对芯片受力的影响,对基座结构进行适当优化,并对比仿真分析的结果;最后通过实验测得优化前后的传感器输出数据.结果表明,传感器基座结构优化后,传感器硅芯片中心最大变形量从2.172μm降低到1.819μm,输出误差从0.95%下降到0.60%.     

绝缘体上硅高温压力传感器研究

采用有限元分析工具ANSYS完成了一种矩形弹性膜绝缘体上硅(SOI)高温压力传感器的优化设计，制作出样品，并与相同结构、工艺的多晶硅压力传感器进行了对比测试。结果表明：1：2的膜片宽长比可以使SOI压力传感器的灵敏度达到220mV／MPa，远大于多晶硅压力传感器的灵敏度(约50mV／MPa)。此外，该传感器能够工作在200℃的高温环境中，有良好的长期稳定性，30d内的零点时间漂移为0．12％。     

非定向氧化锌纳米线阵列的场发射

使用热蒸发的方法在硅基底上制备了非定向氧化锌（ZnO）单晶纳米线阵列。经过热蒸发之后,在硅基底上形成一层均匀分布的 ZnO 点。在这些 ZnO 点上生长出非定向的 ZnO 纳米线阵列,其中的纳米线直径大约在 10 到 20nm 之间。考虑到实用,在制备样品的过程中硅基底的温度始终保持在 500℃ 以下。然后测量了这些非定向 ZnO 纳米线阵列的场发射特性。在 5.5V·μm^-1 场强下得到了 10μA·cm^-2 的场发射电流密度;同时使用透明阳极技术观察了其场发射中心的分布。     

基于压阻反馈信号纳米梁非线性振动控制

研究了基于硅压阻效应纳米梁非线性振动控制方法。在纳米梁固定端上表面粘贴硅压阻膜片,压阻膜片的电阻值随着纳米梁的振动发生变化。利用惠斯通电桥电路提取振动信号作为电压反馈控制信号,控制纳米梁的非线性振动。用多尺度法求解方程,得到系统主共振的幅频响应方程。由幅频响应方程分析系统非线性振动方程解的稳定性,研究了交流激励电压幅值、阻尼、反馈增益参数对系统稳定性和振幅的影响规律。研究结果表明:激励电压由0.25 V减小至0.1 V时,最大振幅衰减60%。无量纲阻尼由0.058 5增加至0.087 8时,最大振幅衰减40%。增大阻尼和反馈增益参数可以减弱甚至消除纳米梁振动的非线性特性。该研究成果为纳米梁非线性振动控制及信号提取提供了一种理论方法。     

基于E型圆膜片的复合差动谐振式敏感元件

对以E型圆膜片为一次敏感元件、一对对称的硅梁谐振子为二次敏感元件的复合差动敏感元件的力学特性进行了分析。给出了其敏感压力、差压、集中力与加速度时,梁谐振子固有频率随被测量变化的解析计算模型。     

新型多晶硅压力传感器

论述了一种新型多晶压力传感器。它采用矩形双岛硅膜结构，多晶硅作应变电阻，二氧化硅介质膜作隔离，用集成电路工艺和微机械加工技术制作 ，因而，传感器具有灵敏度高和高等特点，利用有限元法对双岛结构的应力分布进行了模拟计算，实验结果与理论分析一致。     

一种小量程应变式压力传感器结构设计

提出了一种新型的梁膜结构,其体积较小、应力集中效应明显,特别适合作小量程应变式压力传感器。通过有限元分析发现,当膜片厚度与梁厚度为某一比值时,膜片中心应力值最大,而位移量较小,即传感器灵敏度较大,而非线性较小。设计的传感器样品的灵敏度达0.5 mV/V,总精度优于0.1%F.S。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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-