出口企业计价货币选择研究——从固定价格和生产要素部分进口的角度

在规模报酬不变的出口企业生产函数中引入工具货币计价生产要素假设.在局部均衡的框架下建立了出口计价货币选择的固定价格模型,分析出口企业计价货币选择的影响因素.研究表明,对于贸易对象为非工具货币国的出口企业来说,出口计价货币选择不仅受到本国与工具货币国之间汇率的波动性、本国与进口国之间的汇率波动性以及汇率间的相关性的影响,而且在很大程度上受到以工具货币计价的生产要素在总成本中占比的影响.     

电网电压波动下储能变流器控制策略研究

研究接入点电网电压波动下风电机组储能变流器的控制策略,以提高其应对接入点电网电压波动情况下的应变能力．根据三相电路瞬时功率理论实现储能变换器的有功和无功功率的解耦控制．仿真和实验结果表明,在电网电压发生波动时,储能变流器能给电网提供无功支撑,支持其快速恢复．     

周期性安德森模型的电子结构与自旋涨落性质

采用泛函积分与相干势近似相结合的方法 ,对周期性安德森模型在顺磁相的电子结构和自旋涨落性质进行研究 .结果表明 ,随着温度的降低 ,自旋涨落减弱 .另外 ,体系的磁化率也随温度的降低而下降 .磁化率主要由自旋涨落的性质决定 ,与单电子图像不符     

高能多粒子产生中的随机级联α模型及其C语言实现

介绍了高能碰撞中线性动力学起伏的随机级联α模型，并用Ｃ语言程序实现了这一模型，通过几个典型例子直观地给出了非线性动力学起伏的特征。     

自贡市房价走势分析——基于马尔可夫转换波动和改进的小波神经网络

本文应用马尔可夫转换波动和改进的小波神经网络理论及软件,对自贡市房地产价格走势问题进行分析,建立房地产价格波动模型。得到影响房地产价格的实际利率变动率、人口增长指数、建安成本指数和人均支配收入四大主要因素,对自贡市房地产价格走势进行预测。具有较强的实践性。     

基于色关联高斯噪声理论下捕食者-被捕食者模型中被捕食者的平均灭绝时间

在经典的捕食者—被捕食者模型中,引入分析猎物演化趋势的平均灭绝时间,利用最快下降法,通过理论计算推导得到该模型的平均首次通过时间的解析表达式,对噪声强度及其关联对被捕食者(猎物)和系统的平均灭绝时间之间的影响进行分析.理论计算结果的数值分析研究表明：(1)被捕食者的平均灭绝时间T＋(x－→xu)随加性噪声强度D的变化趋势呈现出单调递减函数图像.(2)平均灭绝时间T－(x＋→xu)随着D的增加而迅速减小,即T－(x＋→xu)关于D呈现出单调减函数的关系图.(3)随着乘性噪声强度Q的增加,T(x±→xu)出现一个迅速增加并达到峰值的过程,然后迅速减小.(4)噪声间关联强度λ对平均灭绝时间T－(x＋→xu)和T＋(x－→xu)呈现出完全不同的影响方式.上述结果可以从统计物理学的角度为濒危物种、稀有珍贵物种保护提供一定理论指导,以确保生物多样性保护更有力地开展.     

基于ARM功率谱分析的喷动流化床压力波动频率特性

在300 mm×30 mm×2 000 mm的喷动流化床煤部分气化试验装置上,采用现代自回归模型(ARM)功率谱分析的方法,系统地考察了喷动气流速、流化气流率、静止床层高度对喷动流化床床层不同位置压力波动主频的影响.结果表明:床层不同位置压力波动的主频随喷动气流速的增大而增大,随静止床高的增大而减小;V型布风板以上床层压力波动主频随流化气流率的增大先增大(Qf/Qmf≤1.0)后减小(Qf/Qmf>1.0),布风板区域内压力波动主频随流化气流率的增大而增大.结合数码CCD图像对结果进行分析,揭示了压力波动主频与床内流动结构的关系,这对于发展喷动流化床技术提供了新的研究方法.     

Synthesis, structure and function of poly-α-amino acids – the simplest of protein models

During the 1950s, linear and multichain poly-α-amino acids were synthesized by polymerization of the corresponding N-carboxyamino acid anhydrides in solution in the presence of suitable catalysts. The resulting homo- and heteropolymers have since been widely employed as simple protein models. Under appropriate conditions, poly-α-amino acids, in the solid state and in solution, were found to acquire conformations of an α-helix and of β-parallel and antiparallel pleated sheets, or to exist as random coils. Their use in experimental and theoretical investigations of helix-coil transitions helped to shed new light on the mechanisms involved in protein denaturation. Conformational fluctuations of peptides in solution were analysed theoretically and studied experimentally by nonradiative energy-transfer techniques. Poly-α-amino acids played an important role in the deciphering of the genetic code. In addition, analysis of the antigenicity of poly-α-amino acids led to the elucidation of the factors determining the antigenicity of proteins and peptides. The synthetic procedures developed made possible the preparation of immobilized enzymes which were shown to be of considerable use as heterogeneous biocatalysts in the chemical and pharmaceutical industry. Interest in the biological and physicochemical characteristics of poly-α-amino acids was recently renewed because of the reported novel findings that some copolymers of amino acids are effective as drugs in multiple sclerosis, and that glutamine repeats and reiteration of other amino acids occur in inherited neurodegenerative diseases.     

渤海沿岸全新世海面升降与半干旱湖区演化的对比研究

全新世时,渤海沿岸海面升降变化与半干旱区湖泊的演化具有明显的同步性。形成的主要原因是与全球性气候变化有关。在弄清不同时间尺度自然变化规律,并考虑到人为因素的影响,可对未来环境演化趋势进行预测。     

Vegetation evolution and millennial-scale climatic fluctuations since Last Glacial Maximum in pollen record from northern South China Sea

A large number of paleoclimate records reveal subMilankovitch climatic fluctuations on the millennial-scalesuperimposing on the Earth orbital cycles[1], such as theHeinrich ice draft events in the Atlantic (each intervalabout 7000–10000 a)[2,3], the Dansgaard/Oeschger (D-O)events (millennial-scale) in Greenland Ice Cores and theBond cycle composed of a Heinrcih event after severalD-O events[4]. At present, most recent work on millennial-scale climatic fluctuations focuses on the high lat…