超声参差宽带阵优化指向特性的计算机模拟

应用声压迭加原理，得到了参差调谐超声宽带基阵换能器的声压响应函数及声压指向特性，并应用波束等价的方法对波束分布的指向特性进行了优化模拟研究．通过对较优波束指向特性进行模拟，可以得到一个具有较优指向特性、布阵合理、阵元频率可参差调谐的宽带阵列换能器的布阵方案，为超声基阵换能器的设计提供了一个新途径．     

新型线列CCD热钢坯长度在线测量系统

提出一种新型线列ＣＣＤ热钢坯长度在线测量系统。该系统采用三块线列ＣＣＤ图像传感器，侧向斜视热钢坯，在有效视场内，对于钢坯±４００ｍｍ的中心偏移和±１５°以内的偏转角，能进行有效的测量，相对测长误差≤±０．６３％，采取适当措施，测量系统能在恶劣的现场条件下可靠地工作。     

圆环形宽带阵列换能器波束优化模拟研究

根据波束等价和采样合成定理，对由若干同心圆环构成的二维非线性参差调谐宽带阵列换能器，进行波束优化计算机模拟．结果表明，给定一个期望的波束分布，通过计算机模拟运算，可获得环形参差阵的一组结构参数，其波束分布与给定的波束分布在误差范围内一致     

精密OTA—C有源移相器的设计

本提出了一种由跨导运算放大器和电容实现的精密移相器。它能使正弦信号在中心频率Ｆ０处，产生－９０°相移，增益为１／２。在ｆ０±１０％范围内，最大相移偏差为±０．１３°，增益最大偏差为±０．００８。移相器的中心频率ｆ０可由ＯＴＡ外控电流调节。由于电路中无电元件，特别适合于单片集成。本详细地分析了ＯＴＡ性能参数对移相器性能的影响，电路的计算机模拟结果与理论分析完全相符。     

精密OTA－C有源移相器的设计

本文提出了一种由跨导运算放大器（ＯＴＡ）和电容（Ｃ）实现的精密移相器。它能使正弦信号在中心频率ｆ０处，产生－９０°相移，增益为１／２。在ｆ０±１０％范围内，最大相移偏差为±０．１３°，增益最大偏差为±０．００８。移相器的中心频率ｆ０可由ＯＴＡ外控电流调节。由于电路中无电阻元件，特别适合于单片集成。本文详细地分析了ＯＴＡ性能参数对移相器性能的影响，电路的计算机模拟结果与理论分析完全相符。     

X线头影测量分析及计算机处理在正颌外科的应用

根据正颌外科的临床需要，采用自然头颅位拍摄Ｘ线头影测量片，以通过鼻点的真正垂直线为基准平面，充分反映颌面部畸形部位和有助于正颌手术设计的１６个角度及１０个距离为测量项目，对２０名广东籍面容端正、咬正常成年女性的Ｘ线头影测量片统计分析，获得了一系列可运用于临床使用的正常标准值，其中：ＳＮ／ＶＰ（８４．５±３．６）°、ＮＡ／ＶＴ（５．５±２．１）°ＮＢ／ＶＰ（５．３±１．１）、ＮＰ／ＶＰ（４．０±２．１）°、ＥＬ／ＶＰ（１８．８±３．８）°。并建立了一套新的具有颅颌面畸形分析、设计模似手术及术后面型预测等功能的正颌外科计算机处理系统。     

层间混杂薄壁圆筒抗弯扭特性的实验研究

对碳纤维与玻璃纤维环氧树脂复合材料，具有０°、±４５°层间混杂铺层的薄壁圆筒在弯一担作用下的力学特性进行了实验研究；解决了试件及其实验专用夹具和测试装置设计与制作的技术问题．本文的方法和结论可为其工程设计与实验测试提供有价值的参考．     

圆环形宽带阵列换能器波束优化模拟研究

根据波束等价和采样合成定理，对由若干同心圆环构成的二维非线性参差调谐宽带阵列换能器，进行波束优化计算机模拟，结果表明，给定一个期望的波束分布，通过计算机模拟运算，可获得环形参差阵的一组结构参数，其波束分布与给定的波束分布在误差范围内一致。     

六层斜压有地形的全球海洋环流数值模拟 一

本研究的第一部分即模式设计部分．为研究大尺度海气相互作用，气候及气候变化，我们参考国外有关区域模式，设计和建立了一个有海底地形的六层斜压全球海洋环流模式．分辨率为５°经度×４°纬度，积分区域为７０°Ｓ和７０°Ｎ之间的全球海区，最大深度３７５０ｍ．模式方程为静力近似和Ｂｏｕｓｓｉｎｅｓｑ近似下的原始方程，模拟海流，温度和盐度．以年平均风应力，年平均海表热通量和盐通量作为强迫条件，从静止状态开始积分，时间足够长以后获得稳定的海流．温、盐分布．另一文将叙述模拟及试验结果．     

波致混合对热带太平洋海气耦合模式中冷舌模拟的改进

非通量调整的大气海洋环流耦合数值模式所模拟的赤道太平洋表层海温（SST）的冷舌偏冷并且过于西伸是一个共性问题．文中在全球大气-海洋环流耦合数值模式FGCM-0中考虑了波致混合的作用后，赤道太平洋地区的SST模拟结果有了显著的改善，在（160—180°E，0—3°N）海域内SST升高在0.8℃以上且最大可达1.2℃．这有效地抑制了冷舌西伸，即赤道太平洋冷舌过于西伸的问题有所改善，26.0℃等温线在赤道附近的顶点从165°E东移至180°E以东，大约向东移动了1650km，这样所模拟的SST更接近于观测．对模拟结果分析表明：耦合模式中SST、近海面大气环流、海洋表层水平环流、海洋表层上升流等要素的距平场是相互间动力协调的，对于改善赤道冷舌模拟偏冷问题是正反馈，而耦合模式中海气热通量距平对改善赤道冷舌模拟偏冷问题是一种负反馈．     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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

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