统计估算法在可能最大降水研究中的应用

本文提出一种改进的PMP统计估算法—K_m值法.指出K_m是Φ_M的一致性估计量.分析了适用K_m值法的约束条件.提出样本均值抽样误差的"可能最大"校正的概念.最后通过一个算例介绍了K_m值法的计算步骤.     

可能最大暴雨的一个数值试验研究

本文应用局地细网格降水数值模式,对汉江上游石泉以上流域的可能最大暴雨(PMP)的计算作了数值检验.检验结果表明:用对水汽场进行放大的水汽输送法,所得流域的降水反而减小;即使考虑极端情况,使水汽全部饱和,其他地区的降水虽得到放大,但此流域的降水仍稍有减小.这说明,对计算PMP的现有简化作法用降水动力模式进行一些检验和修正,是必要的.作者並提出,直接应用降水动力模式计算PMP,应是一个值都注意的方向.     

分时段地形增强因子法在山区PMP估算中的应用

在山区可能最大降水研究中,关键是如何估算地形对暴雨的影响.本文首次提出一种定量估算地形对暴雨影响的方法.该法基于天气-气候分析和实测降雨的统计分析,利用二维差分近似估算出特定流域地形对暴雨影响的大小及其时、空变化过程.通过海南岛昌化江流域山地PMP估算的实例,发现地形对暴雨影响的大小及其空间分布是随着历时而变化的.应用此法不仅能估算出山岳区的PMP数值,而且能绘出符合成因分析的PMP等雨量线的时、空变化情况.本文还结合实例分析,指出了"分时段地形增强因子法"在暴雨移置研究中的应用前景.     

可能最大降水估算中气象因子放大的数值实验

本文针对可能最大降水(PMP)估算中常用的气象因子放大方法,应用五层原始方程模式对不同的风场和湿度场配置作数值实验,以检验对降水的影响程度,结果表明:湿度场扰动对降水的作用比风场扰动更为显著.     

位移电压法的改进与仿真分析

位移电压法是间接测量对地电容方法中的一种,但该方法在计算对地电容时,个别结果会出现较大误差.针对这一问题,本文提出了先估算谐振点电感值L,然后以2倍的L值与2.5倍的L值分别调节电感,再使用位移电压法计算对地电容的方法.并利用Matlab仿真平台,建立了中性点经消弧线圈接地的电网模型.在此模型基础上,对改进前后的位移电压法进行了仿真比较,实验结果表明,使用改进后的位移电压法计算出的对地电容更为准确,误差小于1%.     

SD法在西藏贡觉县阿中I号矿区的应用

本文详细研究国内外相关储量计算方法,以西藏贡觉县阿中矿区的资源量估算课题为背景,选用SD法作为储量计算工具来计算矿区资源量。SD法通过对传统法和样条函数法的改进以及与地质统计学法和距离幂次反比法等方法的结合使其在储量估算领域内具有一定的先进性,SD法能根据地质工作阶段划分的要求,正确掌握取样的有限性,确定工程控制程度。     

估算烷烃类有机物同分异构体正常沸点的新方法

元素与化学键贡献法对有机物正常沸点的估算与基团贡献法相比较,其估算精度更高,但该方法的缺点是对同一类的同分异构体则不能区分。本文针对有机物同分异构体的特点提出了用于估算的5种数学模型,将计算值与文献的实验值比较。     

基于MATLAB编程的沉积物粒度计算方法与结果对比研究

以Folk-Ward图解法和Mc Manus矩值法公式为基础,利用MATLAB软件编程编出一套完整的计算粒度参数程序.然后以海州湾潮滩岩芯沉积物为例,分别计算其图解法和矩值法粒度参数并进行粒度含量和参数结果的比较.结果表明,海州湾潮滩岩芯HZ01沉积物样品以粉砂为主,含量平均值为84.7%.其次是黏土,含量为14.6%,砂含量最少,约为0.6%.图解法计算得到平均粒径范围介于7.14Φ~7.71Φ之间,分选系数范围为1.29~1.51,偏态值范围为-0.01~0.11,峰态值介于1.04~1.18之间;矩值法计算得到平均粒径范围为7.24Φ~7.81Φ,分选系数范围为1.29~1.6,偏态值介于0.12~0.98之间,峰态值介于1.71~2.3之间.相关性分析表明两种方法计算的平均粒径与分选系数具有很高的相关性,相关系数分别为0.99和0.94,通过了95%的显著性检验,可以相互替代.而偏态值和峰态值则不具有相关性,相差较大,不可转换.     

近年来我国可能最大暴雨的估算

本文阐述我国暴雨的地域性和季节特征,并介绍几次特大暴雨的实况及其成因。我国河流洪水绝大多数来自强烈暴雨。暴雨洪水离差系数特大,加以实测资料短,用频率分析法推求稀遇洪水时不得不作大幅度外延,因而会造成不确定性并给设计的工程带来危险。因此,由水文气象途径估算PMP是必要的,有可能提高洪水估算的可靠程度。本文根据著者实践经验,综合了我国目前较为实用的三类估算PMP的水文气象学方法,即:暴雨物理因子放大;暴雨移置;暴雨组合。文中还提出了这些方法在工程设计上的应用。     

氢化物HnA中A-H键振动频率规律性的探讨

振动频率是分子结构中的一个重要参数,它的大小反映出化学键的强弱和分子的稳定性。由于测定的实验值为数有限,建立直观而简单的准确估算方法具有重要的理论意义和实用意义。为了计算方便,本文总结出一个新的计算所有常见的氢化物中A-H键振动频率υA-H与价层轨道平均能、键长的关系方程υA-H=1462.45Φ1 1.25Φ-2536.16。该公式简单,参数少,使用起来相当方便。用该公式计算了17个氢化物中A-H键振动频率υA-H,结果与实验数据一致。     

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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