一元一次不等式（组）的应用

一元一次不等式(组)不仅是初中代数的一个重要内容，而且是解决数学问题的一种非常有用的工具．同学们学了一元一次不等式(组)的解法之后，有必要了解它在解题中的广泛应用。     

钢制压力容器分析设计中应力的分类及比较

钢制压力容器的分析设计中,依据JB4732-95《钢制压力容器——分析设计标准》,按＂等安全裕度原则＂应力分为三类：一次应力、二次应力、峰值应力。一次应力没有自限性,必须满足外载和静力平衡关系,按沿厚度分布情况又分为一次薄膜应力与一次弯曲应力;二次应力具有自限性,由同一元件上不同部位材料或相邻元件间的总变形协调条件导得;峰值应力的明显特点是局部性和自限性,是局部结构不连续处总应力去除一次应力和二次应力后的剩余应力。     

一元一次不等式（组）复习指导

一、复习要点 1.基础知识 (1)不等式;(2)一元一次不等式:(3)不等式的解集;(4)一元一次不等式组的解集;(5)不等式的基本性质. 2.基本方法 (1)一元一次不等式的解法:①去分母;②去括号;③移项;④合并同类项;⑤系数化为1. (2)一元一次不等式组的解法:①求出不等式组中每个不等式的解集;②求出这些不等式的解集的公共部分,即为不等式组的解集.     

关于一元二次不等式解法的一种思路

本文介绍把解一元二次不等式转化为解一元一次不等式（组）．     

三个“一次”问题

本文所说的三个“一次”是指一次函数、一次方程和一元一次不等式，一次方程又包括一元一次方程和二元一次方程．这三个“一次”之间有着本质的区别，又存在着内在的联系．     

中考数学中不等式（组）的应用技巧

有关一元一次不等式(组)的解法，以及运用一元一次不等式(组)的知识解决有关数学问题，是中考命题必考的知识点之一，为了帮助同学们搞好复习，现就这类题型举例如下，供参考。     

一次不等式（组）常见问题及纠错训练

在解答一次小等式(组)时。需要掌握有关不等式的基本概念和基本运算方法。并熟练掌握一些解题技巧。同时，还可利用极易出现错误的典型例题，引导学生吸取反面的教训，从而加强对概念的深刻理解，以达到准确灵活解题的目的。下面，就一次不等式和不等式组中常出现的问题给予总结。     

第十一节不等式问题

（1）一元一次不等式：只含有一个未知数,且含有未知数的最高次数是1的不等式叫做一元一次不等式．     

由D触发器改进的边沿JK触发器

由于主从JK触发器对解决一次变化并不太理想，使用方面受到一些限制，而维持阻塞D触发器完全解决了一次变化问题。本文在维持阻塞D触发器组成电路的基础上，增加了三个基本逻辑门构成的JK触发器圆满地解决一次变化。改进后的触发器，具有保持、置0、置1、翻转四种功能，是一种很理想的电路。     

解一元一次不等式组应注意的问题举隅

一元一次不等式（组）是初中数学中的重要基础知识．教科书中主要介绍了不等式的概念、性质和一元一次不等式（组）的解法等．中考时考查的知识点有：一元一次不等式的解法、一元一次不等式组的解法、求一元一次不等式（组）的整数解、确定不等式组中字母的取值范围和不等式型应用题。其中利用不等式知识解决实际问题的考题越来越多，请同学们予以关注．     

单位分数的一个简单性质的应用

介绍了单位分数的一个简单性质,并以129为例,给出了单位分数化循环小数的方法。     

单位分数的一个算术性质

运用数论函数和原根与指数理论证明了：单位分数1／α=0．α1．α2…αr,α1,α2…αr,是循环部分,r是偶数;而且1／α=0．α1．α2…αr,的充要条件是α是一个奇素数,而且10是模α的原根,从而解决了有关单位分数的一个难题。     

有理函数分解成部分分式的几种方法

本文介绍了将有理函数分解成部分分式的实根代入法、复根代入法、极限法、求导法等几种简单方法,简捷有效地解决了有理函数的积分问题。     

有理真分式裂项的快速方法

本文给出了有理真分式裂项的一种简便方法。     

连分数与二次无理数浅析

利用连分数的概念讨论了连分数的一些性质,并探讨了二次无理数与循环连分数的关系及二次无理数的连分数展开式的规律.     

Volumetric fraction measurement in oil-water-gas multiphase flow with dual energy gamma-ray system

INTRODUCTION Oil-water-gas multiphase mixed transport in oil pipe is extensively used in ocean oil industries. How to measure the volumetric fractions of oil-water-gas multiphase flow is an important subject of study in the oil industry. Related research work was started in the 1980s. The measurement of component ratios in multiphase flows using γ-ray attenuation was first suggested by Abouelwafa and Kendall (1980), and the technique has been used in many current com- mercial multiphase…     

Drawing on a Theoretical Model to Study Students’ Understandings of Fractions

Teaching and learning fractions has traditionally been one of the most problematic areas in primary school mathematics. Several studies have suggested that one of the main factors contributing to this complexity is that fractions comprise a multifaceted notion encompassing five interrelated subconstructs (i.e., part-whole, ratio, operator, quotient, and measure). Kieren was the first to establish that the concept of fractions is not a single construct, but consists of several interrelated subconstructs. Later on, in the early 1980s, Behr et al. built on Kieren’s conceptualization and suggested a theoretical model linking the five subconstructs of fractions to the operations of fractions, fraction equivalence, and problem solving. In the present study we used this theoretical model as a reference point to investigate students’ constructions of the different subconstructs of fractions. In particular, using structural equation modeling techniques to analyze data of 646 fifth and sixth graders’ performance on fractions, we examined the associations among the different subconstructs of fractions as well as the extent to which these subconstructs explain students’ performance on fraction operations and fraction equivalence. To a great extent, the data provided support to the associations included in the model, although, they also suggested some additional associations between the notions of the model. We discuss these findings taking into consideration the context in which the study was conducted and we provide implications for the teaching of fractions and suggestions for further research.     

Children’s mental representation when comparing fractions with common numerators

Researchers debate whether one represents the magnitude of a fraction according to its real numerical value or just the discrete numerosity of its numerator or denominator. The present study examined three effects based on the notion that people possess a mental number line to explore how children represent fractions when they compare fractions with common numerators. Specifically, the effect of the spatial numerical association of response codes (SNARC), the distance effect and the size effect in representing fractions were examined in a sample of 72 sixth graders, who successfully solved the fraction comparison task with a real number (.2) or a fraction (1/5) as the reference. Results showed that in the fraction-reference group (1/5 as the reference), there was a significant reverse SNARC effect and a distance effect between the denominators of the target fractions and the reference fraction; in the real number-reference group, the three effects were also observed. These results revealed that both groups used the mental number line to represent fractions and did not represent their real numerical values but rather the discrete numerosities of denominators when comparing fractions with common numerators. It seems that the way people represent fractions may depend on their strategy choices.     

不尽根数与连分数

本文给出了不尽根数的一种近似计算方法 :连分数 ,并证明二次不尽根数必为循环连分数的结论     

两类有理分式的高阶导数

讨论两类有理分式的高阶导数的求法,得到了两组导数公式。用公式求相应的有理分式的高阶导数。能起到较好的简化作用。