A review on some classes of algebraic systems

ABSTRACT

In this paper, we review some algebraic control system. Precisely, linear and bilinear systems on Euclidean spaces and invariant and linear systems on Lie groups. The fourth classes of systems have a common issue: to any class, there exists an associated subgroup. From this object, we survey the controllability property. Especially, from those coming from our contribution to the theory.     

宁夏宁东供水工程主机设备形式参数选择与国际招标

宁东供水工程供水水泵共有卧式和立式离心泵2种方案可供选择,也是工程论证时争论的焦点,经综合比较及主机设备的国际招标,最终确定了奥地利安德里兹公司的卧式双吸中开式离心泵为宁东供水工程的供水水泵。     

电子表格EXCEL5.0在选煤线性规划问题中的应用

采用电子表格软件ＥＸＣＥＬ５．０可以方便地解决许多选煤生产中的线性规划问题。本文通过选煤过程线性规划实例介绍ＥＸＣＥＬ５．０在此领域的应用方法。     

灰铸铁石墨形态的研究

文本研究了化学成份与冷却速度及孕育处理对灰铸铁石、墨形态的影响．并对形成的地B、C、D、E、F等六种衣铸铁石墨形态的形成条件作了讨论．     

粘土矿物对低渗透储层性质的影响——以鄂尔多斯盆地三叠系低渗透储层为例

粘土矿物是低渗砂岩储层的主要胶结物，对储层物性及开发过程中储层物性变化趋势有着重要的影响和控制作用。另外，粘土矿物也蕴含着大量沉积环境介质的物理化学信息，认识其自然规律，可以有效地指导预测有利储层，认识和改造油层。以鄂尔多斯盆地砂岩储层中的粘土矿物为研究对象，探讨分析粘土矿物对低渗储层性质的影响，该研究对含油气盆地低渗储层有效开发具有一定的参考价值。     

冲切成槽法在薄壁砼防渗墙施工中的应用

冲切成槽法施工薄壁砼防渗墙,是一种新型防渗墙施工方法,它是利用特制的扁钻头对风化基岩或卵石层进行冲切成槽的施工方法,在工艺上有着较强的优越性.     

曲面的第Φ_r-形式在广义Ⅱ-等距下的公式

给出曲面的第Φr 形式在广义Ⅱ 等距下的公式的概念.借助混变张量,得到曲面的第Φr 形式在广义Ⅱ 等距下的公式.     

Constructing a short form of the Smoking Consequences Questionnaire with adolescents and young adults.

The goal of the present studies was to construct and validate a short form of the 50-item Smoking Consequences Questionnaire (SCQ; T. H. Brandon & T. B. Baker, 1991), a measure of smoking outcome expectancies. In Study 1, a 21-item short form (S-SCQ) was derived from a sample of 107 young adults previously treated for substance abuse. In Study 2, the measure was cross-validated on 125 adolescents in treatment for substance abuse. Confirmatory factor analyses revealed good model fit and factorial invariance for the 4 S-SCQ subscales across both samples. Validation analyses on each sample found that subscale scores generally correlated significantly with smoking-related variables. The present studies provide initial evidence for the utility of the S-SCQ when used with young adults and adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

某跨线桥施工支架方案设计

结合某大桥的概况,根据梁体施工工艺要求、现场实地勘察情况确定跨线施工方案,支架采用布架灵活、搭拆方便、承载力大的WDJ碗扣式多功能钢支架,部分预应力现浇连续箱梁采用支墩加纵梁预留门洞的支架现浇,取得良好效果。