差分式微电容加速度计的数学模型及应用

介绍了一种基于MEMS和表面微加工工艺的差分式微电容加速度计,并通过分析,构建了该加速度计的数学模型,并简要介绍了该加速度计的一些简单应用.     

二阶变系数线性微分方程的求解

二阶线性齐次微分方程在微分方程理论中占有重要位置,但二阶变系数线性微分方程却没有一般的求解方法,给出了几种通过变量变换将二阶变系数线性微分方程化为二阶常系数的线性微分方程的充分条件.     

利用微分方法计算一类积分问题

一类形如∫f（x）e^ax sinβxdx,∫f（x）e^ax cosβxdx等的积分运算问题利用微分算子方法可以化为微分运算，且使运算简便、快捷．     

弯管流量计在高温工作环境下的误差分析

本文从弯管流量计在高温工作环境和理论设计环境的条件变化出发，分析了温差存在条件下的误差产生原因，并提出了有针对性解决的方法。     

Differential Performance of Items in Mathematics Assessment Materials For 7-Year-Old Pupils in English-Medium and Welsh-Medium Versions

This paper draws on data from the development of annual national mathematics assessment materials for 7-year-old pupils in Wales for use during the period 2000–2002. The materials were developed in both English and Welsh and were designed to be matched. The paper reports on item analyses which sought items that exhibited differential performance in relation to whether the materials were English medium or Welsh medium. The items that exhibited consistent differential item functioning in relation to language during pre-testing are reviewed in order to discuss the linguistic factors that could affect such behaviour.     

Using the United States Census Data to Introduce Differential Equations

Abstract

This article describes a method for using the United States Census data to open a differential equations course. The question of finding a model for the United States population data gives students a first experience with creating a model using differential equations, and also understanding derivatives, what they mean, and how to calculate them in the context of real data. This model-building start motivates further exploration in many of the standard differential equations topics: the method of separation of variables, slope fields, autonomous equations, equilibria, and stability.     

临界状态下一阶中立型时滞微分方程的线性化振动性

在临界状态下建立了一阶非线性中立型时滞微分方程(x(t)-cx(t-τ))’ ∑pix(t-τi) f(t，x(t-σ1(t))，…，x(t-σn(t))=0与一个相关的二阶常微分方程振动性等价定理，进而给出了一阶非线性中立型微分方程(x(t)-cx(t-τ))’ ∑pif(x(t-τi))=0与相应的线性方程振动性等价的充分条件，从而推广了[1]的相应结果。     

营销新思维：利润差异化营销

面对竞争纷呈和消费需求的变化，企业只有也必须转换营销思路，才能异军突起。利润差异化营销方式不仅蕴涵了历史经验中最好的营销方法，而且兼顾了有效妥协于现状的营销概念。它既是对传统营销模式的修正，也是一种营销新思维，不失为一种最佳的营销策略。     

关于二阶微分方程的周期解

着重研究二阶微分方程x··=a0 0 +a1 0 x+a0 1 x·+a2 0 x2 +a1 1 x·x·+a0 2 ·x·2 +… +aa0 xn+… +a0a(x·) n 借助于中介函数变换U(t) =U(t,x(t) ) ,将其解与一定的黎卡堤方程dudt=α0 +α1 u +α2 u2 发生关系 ,从而通过黎卡堤方程来研究二阶方程。     

浅谈微分中值定理证明中的辅助函数

三大微分中值定理的证明是高等数学教学中的重要内容,文章利用函数叠加的方法给出了一种新的证明方法。