一个新的数论函数及其均值性质

对于给定的自然数q,我们利用最小公倍数定义一个新的数论函数g(n)=[q,n]/q.本文的主要目的是研究δm(g(n))的均值性质,并利用解析方法得到这个函数的几个渐近公式.     

植物导水模型初探

目前世界上对于植物长距离水分运输的微观机理假说存在争论。据此本文初步讨论了植物的导水模型。从流体力学角度讨论了水分在植物体内的运动状态,得出导管中的水分流动是在层流的状态下进行,且必须考虑粘性的作用;通过分析流体的层流运动,建立了导管中一维的流体模型,并简化导管以连续的梯形圆柱排列;分析受力,列出N-S方程,并求解出了一维导管模型的半径与压力梯度和各节管长的关系表达式。研究结果表明,模型中每一节导管的水受力都是平衡的,且各节之间相互独立。     

Effect of Sputtering Parameters on Film Composition,Crystal Structure,and Coercivity of SmCo Based Films Deposited on Si （100） Substrates

The sputtering parameter mediated composition （SPMC） effect of 3.0-μm-thick SmCo-based films is experimentally and theoretically studied. The experimental results give a clear indication that the Sm concentration increases with the decreasing sputtering power or with the increasing Ar gas pressure, which are in agreement with the calculated values when the preferential sputtering effect is disregarded. The SPMC effect provides an opportunity for the same composite target to fabricate films with an Sm concentration varying from 13.8at.% to 17.3at.%, which is reasonable for the magnetic phase transformation （Sm2Co17→SmCo7→SmCo5） and the enhanced coercivity.     

无损贮存及涨罐饱和相热力学模型研究

在低温液体无损贮存及涨罐研究方面,经常采用一种假设容器内气、液相均为饱和相的热力学模型.这种模型比较符合实际,并能够大大简化容器内的热力学状态,是一种比较常用的热力学模型.文中利用一个5m3低温贮罐进行的液氮无损贮存及涨罐试验,对该热力学模型进行了对比研究,讨论了饱和相热力学模型误差产生的原因,对于无损贮存和涨罐研究具...     

New microscopic wave function of ��-condensation

We explain how to treat a microscopic wave function of ??-condensation taking a 3??-nucleus as a typical example. The wave function has been originally proposed ten years before by Horiuchi, R?pke, Schuck and the present author (Phys. Rev. Lett., 2001, 87: 192501). The microscopic model, which fully takes into account the Pauli principle between all the constituent nucleons, effective internucleon forces and the Coulomb force, can play an important role in reproducing an ??-gas nature thanks to ??-condensation as an excited state of ??-like nuclei. An essential point of the wave function is to describe their ground state simultaneously. We study its typical features by giving an analytical formula of the norm kernel and the kernel concerning the one-body operator for 3??-condensation.     

数学与系统科学方法在宏观经济管理和公共政策分析中的应用专辑 序言

宏观经济管理和公共政策分析是两个非常重要的学科领域,大量使用统计学模型、计量模型、优化模型、对策论模型和其他数学与系统科学分析工具.高度关联状态下世界经济的脆弱性和社会系统的复杂性,给宏观经济管理和公共政策分析带来了若干全新的     

基于可计算一般均衡模型的出口退税政策效应分析

使用Chinagem模型计算了我国2010年6月份出口退税率下调对我国经济以及各行业的影响.研究表明,此次调整导致我国GDP实际减小0.016%,投资、出口与进口分别下降0.075%、0.041%与0.116%,居民消费和政府消费上升0.005%,就业下降0.016%,两高一资行业受挫较大.同时,各个行业实施出口退税时,对该行业的影响表现为:将直接导致行业出口价格上升,出口量下降,从而国内销售部分增加;由于国内供给增加,进口有所减少;而总产出的变化则由于行业不同而呈现出不同的变化.与此同时,各个行业出口退税率的变化将导致上游行业产出下降,下游行业产出增长.     

基于等额本息按揭贷款的脉冲增加还款模型

利用一阶线性差分方程建立了每隔半年增加还款一次的按揭贷款数学模型,并通过实例说明了其在经济生活中的具体应用.     

THE EFFECT OF BILINEAR BEHAVIOUR ON THE DIRECTION AND MAGNITUDE OF THE PEELING MOMENT IN A BI-MATERIAL BEAM

In this work a bi-material beam exhibiting partly bilinear behaviour under a uniform temperature change is analyzed. The essence of solution is based on the approach of Timoshenko’s mechanics of materials. The main aim of the present analysis is to understand the effect of the bilinear behaviour on the peeling moment. This theoretical mechanics model mentioned here can give us useful insights to improve the resistance against the delamination.     

THE COMPACTION OF TIME-DEPENDENT VISCOUS GRANULAR MATERIALS CONSIDERING INERTIAL FORCES

In the present paper, compactions of time-dependent viscous granular materials are simulated step by step using the automatic adaptive mesh generation schemes. Inertial forces of the viscous incompressible aggregates are taken into account. The corresponding conservation equations, the weighted-integral formulations, and penalty finite element model are investigated. The fully discrete finite element equations for the simulation are derived. Polygonal particles of aggregates are simplified as mixed three-node and four-node elements. The automatic adaptive mesh generation schemes include contact detection algorithms, and mesh upgrade schemes. Solutions of the numerical simulation are in good agreement with some results from literatures. With minor modification, the proposed numerical model can be applied in several industries, including the pharmaceutical, ceramic, food, and household product manufacturing.