介电常数呈阶跃型分布的一维光子晶体带结构

借助加速器概念和矩阵转移方法对介电常数呈阶跃型分布的一维光子晶体进行了研究,自动呈现出了光子晶体的带结构,禁带宽度由公式△ω=c/ηx0[π-2/[1＋l/（2x0）]^1/2]给出.结果表明,禁带宽度与宽度比l/x0有关.宽度比l/x0越大,禁带越宽.     

Pythagorean三角形的结构

本文给出Pythagorean三角形(x,y,z)的一般形态,即x、y、z呈形x=k/4{[(2a_0 d) c_02~(1/2)](1 2~(1/2))~(2n) [(2a_0 d)-c_02~(1/2)](1-2~(1/2))~(2n)-2d}y=k/4{[(2a_0 d) c_02~(1/2)](1 2~(1/2)) [(2a_0十d)-c_02~(1/2)](1-2~(1/2)~(2n) 2d}z=k2~(1/2)/4{[(2a_0 d) c_02~(1/2)](1 2~(1/2))~(2n)-[(2a_0 d)-c_02~(1/2)](1-2~(1/2))~(2n)}其中a_0 、c_0、d、k∈N,n∈N~ =NU{0}且(a_0,a_0 d,c_0)∈M_d.     

压电晶体在水溶液中的振频特性

晶体停振温度、频移及接地效应与溶液电解质浓度有线性关系,接地可显著降低停振温度与浸入深度的影响.     

槽型减摇水仓特性参数的理论估算和试验方法

国外有关研究认为:槽型减摇水舱由于缺乏足够的理论计算方法,因此减摇效果预报只能依靠试验。上海交大船池对槽型水舱进行了专门的试验研究。本文根据渡边惠弘、Goodrich、Lewison、Webster 等理论方法的特点,发展了槽型水舱的综合模型,求得了适用于各种尺度比例的周期公式,井初步建立了估算阻尼的理论方法:通过能量方程积分实现分布参数系统向集中参数系统的转换,从而确立阻尼系数和水舱几何尺度的数学关系。本文并力图给出完全的舱船系统简化横摇运动方程组(?)周期系数λ=(1 2r(s-b)(π/4 l/b)(π/B))~(1/2)阻尼系数W=(l r)/(2h_0)(π/(λcos(ω_0l)/(c_0))·(2r/B))~2[2(2.23b/r 1)1g(s/b 1/2)~2 1.5(s/b)~2]力矩系数M_t=2ρg(l r)[2rs(c_0)/(ω_0)(tg(ω_0l)/(c_0) yg(ω_0r)/(c_0)) b(Hh_0-(h_0~2)/2)cos(ω_0r)/(c_0)]为测定水舱特性参数,特别设计了强迫摇摆装置和动力衰减试验方法。试验结果和理论计算结果吻合。看来应用理论方法设计最佳槽型水舱并预报其减摇效果是完全可能的。     

无宏观缺陷水泥基复合材料的介电性能

在 1 0 2 ～ 1 0 7Hz频率范围内测定了酚醛树脂 -高铝水泥基无宏观缺陷 (MDF)材料的介电常数和介电损耗随材料组成及环境湿度的变化曲线 .结果表明 ,MDF材料的介电常数和损耗皆与测试频率有关 ,介电损耗由载流子屏蔽跳跃引起 .当材料内酚醛树脂的数量增加时 ,介电常数下降而损耗略有上升 ,添加硅灰能显著改善材料介电性能 ;在低相对湿度下 ,湿度对介电性能影响不大 ,在高相对湿度下 ,介电常数和损耗都有较大的增加     

科特(Couette)数Pr=1的环隙科特紊流

本文论述了科特数Pr=1的这种流动的研究成果。实验是在剪切流已充分发展,泰勒涡充分抑制的始发条件下在η=R_2/R_1=1.022的设备中进行的。第1次取得了覆盖整个不可压缩流范围(V_0=4.96～80m/s)的这种流动的定常的二维流场数据。实验证明:贴近动壁存在一厚度为δ/h=10/Re c_(f1)~(1/2),流速为1-μδ/V_0=(Reδ)~(1/2)·(c_(f1)~(1/2)=10 (c_(f1))~(1/2)的线性层,文中还提出了动壁面的阻力系数为c_(f1)=0.01/Re~(0.15)与断面平均流速公式v/V_0=0.89/Re~(0.214),以及经过修正后的对数圆周切线速度模型u/V_(max)=■/V_0In(h-αδ)/(y-αδ)。这个模型能准确地通过线性层端点(δ/h,uδ/V_0),平均流速点(y/h=0.368,■/V_0)与最大流速点(y/h=1,V_(max)/V_0=1)的坐标。     

方程(Ⅱ)_(l=0)的无环结构稳定的全局结构与分支

本文讨论了方程(Ⅱ)_l=2在具有P_1P_2S_1S_2 FPS型奇点时无环结构稳定的全局相图及分支曲面,得到了:在条件0>27a>4m~3下,当δ≥0时,恰有三种拓扑结构(W_8,W_(11),W_(12)[2]),且恰有c_1,c_3两种分支,c3曲面方程可写为a=a(m,δ)及m=m(a,δ)的形式,而a(m,δ)是一个无理函数,c_1分支可写为δ=δ(a,m)的形式;当δ<0时,恰有W_5,W_6,W_8,W_(11),W_(12)及[3]中的表1.1(这种结构以下简称为史表1.1)六种拓扑结构,在参数空间存在c_1,c_2,c_2~*,鞍结分支,c_3,c_6六种分支。其中鞍结分支是一条直线;c_3,c_6可用无理式表为a=a(m,δ);c_3还可表为m=m(a,δ)δ=δ(a,m);c_1,c_2是单叶的。最后我们用了一种新的方法证证了c_2~*曲面单叶性。δ,m的一一对应性等。另外,我们还顺便得到了当0>27a>4m~3,a相似文献   

带滞量微分方程解的表达式的一个推广

利用复函数方法讨论了方程a_nx~(n)(t)+a_(n-1)x~(n-1)(t)+…+a_0x(t)+bx(t-τ)=(t~k+c_(k-1)t~(k-1)+…+c_1t+c_0)e~(αt)cosβt a_nx~(n)(t)+a_(n-1)x~(n-1)(t)+…+a_0x(t)+bx(t-τ)=(t~k+c_(k-1)t~(k-1)+…+c_1t+c_0)e~(αt)sinβt解的一些表达式,获得了更一般的结果,推广了最近文献中的有关结果     

一维光子晶体的光子带隙研究

通过改变一维光子晶体的周期排列常数、两种介质的折射率比观察了电磁波在光子晶体中的光子带隙(PBG)行为.当两种介质的排列周期常数a:b=1:1和1:2时,发现光子晶体在可见光区存在一个很宽的频率截止带,即光子带隙区.另外,当两种介质的介电常数比εα:εb小于1:5,在可见光区无光子带隙存在;而当该比率大于1:5时则出现一个很宽的光子带隙.说明两种介质的介电常数比对光子带隙的影响很大,该比例越大,越容易获得光子带隙.     

电离层中标准电波的Doppler频移

指出了电离层的结构对电波传播过程的影响：使标准电波产生DOPPLER频移，并给出了标准电波的频移△f与标准电波的频率f之间的定性关系：（1）当电离层的层状结构随高度变化很小时：△f∝f，这时的频移主要是由反射高度的变化引起的；（2）当折射指数μ变化很小，并且忽略电子碰撞和地磁影响时，△f∝1/f，这时的频移主要是由群路径上μ的变化（即大气浓度的变化）引起的，标准电波的频移主要是由两个方面的因素引起的，从积分路径上看，频移与群路径本身的变化有关，即与反射高度的变化有关；从积分变量上看，频移与路径上折射率指数的变化有关，而折射率指数的变化主要体现在电离层中电子浓度的变化，正因为电波的频移与电离层之间的关系如此密切，对电波频移的探测就显得尤为重要，由此可以预测到电离层的许多突发性事件。     

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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