叉指式硅微加速度计的结构设计

为了满足对中等精度的微机械加速度计的需求,讨论了一种硅片溶解法制造的平面叉指式加速度计,其敏感轴平行于检测质量平面。为了分析该种加速度计的分辨率和固有频率,分析了其机械模型和数值解,并且用有限元方法对几种设计尺寸进行了仿真。着重研究了几个关键尺寸,如检测质量厚度和梁的宽度的改变对分辨率和固有频率的影响,并且给出了此种结构在当前条件下的所能得到的测量分辨率极限。最后,给出了两种尺寸的设计,其大小约为１．５ｍｍ×１．５ｍｍ,检测质量厚１０μｍ和１５μｍ,相对于当地重力加速度,分辨率分别为５×１０－３和３×１０－３。     

院校新闻

近日,北京维信诺公司与清华大学共同研制成功一款全彩色有机发光显示屏,尺寸为1.28英寸,显示色彩为26万色,分辨率为64×3×64。该显示屏在研制     

矢量量化及其硬件实现

介绍了矢量量化的基本原理。采用矢量量化方法对分辨率为512×512的数字图像进行了计算机模拟,使由原图像的8 bit/像素降到了0.5bit/像素,同时用硬件实现了矢量量化编码.在硬件实现中,其主要部件采用74S器件,用绝对值减法器作为失真运算器以及编码器.与计算机的数据交换采用DMA方式,大大降低了编码时间.完成一幅分辨率为512×512的数字图像的16:1压缩仅需9s时间。     

基于隧道效应的nm级三维轮廓仪的研究

介绍两种不同结构形式的基于电子隧道效应的ｎｍ级三维轮廓仪。其纵向分辨率可达０．０２ｎｍ，横向分辨率可达０．２ｎｍ，扫描范围分别达到４０μｍ×４０μｍ和１４０μｍ×１４０μｍ。     

60阶单群的一个简证

本文通过对正多面体回转分类的研究,简化前人对多面体回转群阶数和结构的讨论,并用以简捷地证出正十二面体(二十面体)回转群为60阶单群。 [定理1]正多面体回转群的阶数为uv,其中u为正多面体的面数,v为每一面的正多边形的边数。(因此,正四面体回转群之阶数为4×3=12,正六面体回转群的阶数为6×4=24,正八面体回群之阶数为8×3=24正十二面体回转群之阶数为12×5=60,正二十面体回转群之阶数为20×3=60)。     

石龙子rADVR突触结构的定量分析

用实物及计算机投影系统对石龙子前背侧室嵴嘴外侧区突触的电镜图像进行放大处理和统计分析,测量结果:突触前膜平均厚度为70.3×10-10m,后膜平均厚度为117.7×10-10m,突触间隙平均宽度为147×10-10m,突触界面曲率为:平均值±标准差=(1.123±0.389)×10-10m,突触活性带长度为:平均值±标准差=(3 514.93±982.75)×10-10m,空心小泡直径为:平均值±标准差=(477.3±38.45)×10-10m(n=58),实心小泡直径为:平均值±标准差=(892±55.83)×10-10m(n=28).     

多级雪崩室的性能研究

試制了一个有效面积为100×100mm~2的多级雪崩室。文章简述了这种室的工作原理、结构和性能,并给出了测試结果。     

W51巨分子云及其高密度区的结构: CO(J=1-0)和HCO+(J=1-0)谱线的成图观测

给出了W51巨分子云的大尺度的CO(J=1-0)成图, 大小为15′×15′, 覆盖了W51巨分子云区域中恒星形成最活跃的部分, 同时还给出了W51巨分子云区域内以W51IRS1为中心的小范围(2′×2′)的高空间分辨率8.″7×6.″1的HCO⁺ (J=1-0)成图. 从观测结果分析得到了W51巨分子云的结构模型, 认为分子云内有许多小的云核结构, 它们各自向着自己的中心塌缩, 这些小的分子云核结构是由于W51巨分子云与速度为60~73 km·s^−1的前景云发生碰撞而形成的. 通过对HCO⁺ (J=1-0)成图观测新发现了16个分子云核.     

碘海醇注射液的热分解反应动力学

测定了碘海醇注射液在60°C、80°C下因受热分解而产生的碘离子浓度随时间的变化,研究了碘海醇注射液的热分解反应动力学。结果表明:碘海醇注射液的热分解反应为一级反应,在60°C和80°C时,热分解速度常数分别为5.9×10-6d-1和7.2×10-5d-1,碘海醇的分解活化能Ea=122.1kJ/mol,热分解速度常数与温度的关系为k=3.51×1013e-14716/T。     

485型涡流室式柴油机起动性能的研究与改进

柴油机燃烧室的结构对发动机的动力性、经济性以及起动性等有着决定性的影响。本文主要介绍通过改进485型柴油机涡流室式燃烧室的结构来改善起动性。由新设计的涡流室镶块所构成的球锥形平底涡流室称QZ型涡流室式燃烧室。它的容积比V_k/V_c=38.5％;压缩比ε=20.5;通道面积比f_k/F=0.96％,通道倾斜角α=40°;涡流比Ω_c≈47;漏斗形起动孔30°×φ2mm,倾斜角β=60°;镶块的球锥母线半径R=30.5mm。实验证明,QZ型涡流室冷机起动性能较好,在气温10℃时,不用预热即可顺利起动,显然优于原机涡流室和D型涡流室;在负荷特性上,在标定功率37PS时测得燃油消耗率g_e为198.58/(PS·h),比原机降低6.4g/(PS·h),在标定转速2000r.p.m.时测得功率N_e为41.3PS,比原机增加1PS。     

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.     

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