四个幂等矩阵线性组合的幂等性

给出了当P1,P2,P3,P4 是四个不同的非零的两两可交换的n×n 幂等矩阵并且c1, c2, c3,c4 是非零复数时, 线性组合c1P1+c2P2+c3P3+c4P4在两两乘积等于零与两两乘积等于其中一个的条件下仍是幂等矩阵的一些充要条件.     

幼儿创造性养成:反思和重构

当今社会需要创造性的人才,而人才的培养要从幼儿期开始,本文从培养幼儿创造性的意义,当前存在的问题以及对策方面进行了初步的阐述.     

A combination of leaf rust resistance gene Lr34 and lesion mimic gene lm significantly enhances adult plant resistance to Puccinia triticina in wheat

Leaf rust caused by Puccinia triticina is an economically-important disease in wheat worldwide.A combination of different types of resistance genes may significantly enhance rust resistance under rust-favorable conditions.To investigate the interactions between the rust resistance gene Lr34 and the lesion mimic gene lm on 1BL in Ning 7840,a segregating F8-10 population of 180 recombinant inbred lines was developed from Ning 7840/Chokwang and evaluated for both lesion mimic expression and leaf rust response at the adult plant stage in a greenhouse.A major quantitative trait locus(QTL),derived from Sumai 3,was co-localized with Lr34 on chromosome 7D and explained 41.5% of phenotypic variations for rust severity and 22.1% for leaf tip necrosis(LTN).The presence of Lr34 was confirmed by Lr34-specific markers cssfr1 and cssfr2 in Ning 7840 and Sumai 3.Unlike Lr34,lm conditioned a spontaneous lesion mimic phenotype and had a significant effect on reducing uredinial size,and a smaller effect on severity.Additive effects were observed between lm and Lr34 for severity and LTN,and an epistatic effect was observed for infection type.Single marker analysis also identified several other QTL with minor effects on severity,infection type,or LTN.     

专家-模糊PID算法在孵化机温控系统的应用

蛋类孵化对温度控制的要求较高,为了提高孵化机温控系统的控制效果,基于专家-模糊PID算法理论,通过MATLAB仿真和实验,验证了文中所阐述的方法与常用的PID控制相比,能使孵化机温控系统根据热负荷变化在线修改控制参数,并具有更好的控制效果和鲁棒性。     

防潮母料的制备工艺及性能研究

文章以氧化钙为主体材料制备具有吸湿消泡功能的防潮母料,研究了母料的工艺配方.测定了各项物理性能.结果表明,该母料具有良好的吸湿消泡性和物理稳定性,优于同类产品,可以有效提高生产率,降低生产成本.     

走出“科技”误区——对科学与技术的区分和理解

人们在使用"科学技术"概念时,往往忽略了"科学"与"技术"二者的区别.生物化学家邹承鲁曾指出,"科技"一词主要指科学和技术,有时则完全指技术,而很少指科学:在一些场合,政府领导提到"科技"时,一成不变地意指"技术";即使在提到基础研究的场合,"科技"实际上也仅指技术科学的基础部分[1].把科学与技术混同起来,把科学评价标准与技术评价标准混同起来,内行搞不清楚,外行更是雾里看花.     

大口径塑料管的性能及应用概述

文章对各种大口径塑料管道的发展动态、种类、工艺性能、特点及应用进行了分析和探讨.     

柑橘上施保克及其降解产物的GC快速检测

阐述了GC－ECD检测柑橘上施保克及其降解产物残留的快速分析方法，这种方法可以同时处理多个样品且不需大量的玻璃器皿和试剂，药品，比现有的方法更简捷，快速，该方法的检测限为0．002mg/kg，回收率的范围为81．5－96．0％，并用该方法测定了实际样品的动态消解曲线和相关系数。     

基于ISO 9001标准趋动的独立学院教育质量体系改进实践探讨

在高等教育领域引入ISO 9001质量管理体系是保障和提高高校教育质量的一种长期而有效的途径.通过对ISO 9001质量管理体系在提高独立学院教育质量的应用与实践过程中存在的关键问题进行探讨.以统一思想和行动.保证质量管理体系的顺利运行和教育质量的持续改进.     

Secure and efficient elliptic curve cryptography resists side-channel attacks

An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem (ECC), an efficient fractional width-w NAF (FWNAF) algorithm is proposed to secure ECC scalar multiplication from these attacks. This algorithm adopts the fractional window method and probabilistic SPA scheme to recondigure the pre-computed table, and it allows designers to make a dynamic configuration on pre-computed table. And then, it is enhanced to resist SPA, DPA, RPA and ZPA attacks by using the random masking method. Compared with the WBRIP and EBRIP methods, our proposals has the lowest total computation cost and reduce the shake phenomenon due to sharp fluctuation on computation performance.