Δ3-1,2,4—噻二唑类化合物的量子化学及构效关系研究

Δ3-1,2,4—噻二唑类化合物具有抑制黄瓜霜霉病毒的杀菌活性。本文用半经验PM3方法对25个该类化合物进行了量子化学计算,并依据原子的净电荷、前沿轨道能级、轨道主要成分及原子在前沿轨道中所占比重等计算结果和多重回归分析讨论了该类化合物的活性部位,为该类化合物结构与活性的研究奠定了理论基础。     

一种基于信任关系的网构软件安全模型及其应用研究

作为一种新的软件架构概念和技术,网构软件成为当前软件工程研究领域的焦点之一。然而新的架构技术和运行环境也使得网构软件技术面临着一些新的问题,其中包括网构软件的信息安全性问题。为了实现对网构软件的信息安全保护,本文提出了一种基于信任关系的网构软件安全保护模型,它通过建立网构软件中各软件主体之间的信任关系,达到对网构软件中信息的安全保护目的。     

Innovations in Individual Feature History Management—The Significance of Feature-based Temporal Model

A feature relies on three dimensions (space, theme, and time) for its representation. Even though spatiotemporal models have been proposed, they have principally focused on the spatial changes of a feature. In this paper, a feature-based temporal model is proposed to represent the changes of both space and theme independently. The proposed model modifies the ISO’s temporal schema and adds new explicit temporal relationship structure that stores temporal topological relationship with the ISO’s temporal primitives of a feature in order to keep track feature history. The explicit temporal relationship can enhance query performance on feature history by removing topological comparison during query process. Further, a prototype system has been developed to test a proposed feature-based temporal model by querying land parcel history in Athens, Georgia. The result of temporal query on individual feature history shows the efficiency of the explicit temporal relationship structure.

植物病害I—S关系——logistic衍生模型的研究

以logistic模型为基础 ,以时间因子为媒介 ,推导出一个能准确描述植物病害I-S的logistic衍生模型。通过对油松落针病、花生锈病、烟草黄瓜花叶病和小麦赤霉病等多组I-S关系数据的实例验证与比较分析 ,显示出这一模型具有较强的数据拟合能力和广泛的适用性。Logistic衍生模型尚可应用于林木胸径与材积(D -V)关系、径与树高(D -H)关系以及生物量预估等项研究。此外 ,还提出一个具有普遍指导意义的通用模型     

少数民族流动人口研究综述——以2008年以来CNKI数据库分析为例

近年来关于少数民族流动人口研究颇多,侧重点集中在少数民族流动人口现状、特点的总体分析、城市适应问题、子女教育问题、民族差异引发的社会问题、社会保障与权益保护问题、对城市民族关系的影响等方面。总结、归纳、分析、概括以上多方面的研究成果,对研究存在的问题及空白点加以剖析,以求从全局的角度关注此研究。     

三唑类化合物分子结构与防治小麦锈病活性关系的研究

本文用多元线性回归分析、逐步线性回归分析、主成分回归分析和偏最小二乘分析方法研究了三唑类化合物结构与防治小麦锈病活性的关系，并建立了构效关系式。对该系列化合物结构的变化对其生物性的影响作了一定的探讨。提出了设计高活性化合物的可能结构要求，并将研究结果用于实际化合物的设计中，取得了初步结果。     

Fracture mechanics of air-entrained concrete subjected to compression

Air voids are entrained in concrete for protection of constructed elements, especially highway pavements, against freeze-thaw damage. Entrained air void systems inadvertently reduce the compressive strength of the concrete. The present study describes development of an analytical model for evaluation of the effects of entrained air void system on the compressive strength of concrete. The model developed here will assist in predicting the compressive strength of concrete for specified mix designs. The constitutive relationships for air-entrained concrete were established by considering a micro cracked porous material with randomly distributed circular air voids and uniformly oriented cracks from the air voids. Linear elastic fracture mechanics was employed to explain the evolution of damage due to the individual voids and cracks that emanate from such voids. The damage model considers the interactions among the voids and cracks during various stages of loading. The analytical results from this study were evaluated through an experimental program for comparison of the computed and measured compressive strengths. A wide range of samples were examined that included concretes with air contents ranging from 2% to 13% air by volume of concrete. The experiments involved microscopic determination of air content and spacing factors as well as compressive strength tests for all the concrete samples.     

一种基于关联矩阵的时态关联规则挖掘算法

提出一种新的有别于将时间直接代入关联规则挖掘过程的方法。该方法分别针对确定的有效时间与不确定的有效时间两种情况,通过计算时态数据库中同一对象的元组中指定属性的有效时间之间的同时关系,将所有两两之间具有同时关系的归为一组,从而可以略去元组中的时间因素,并将时态数据库转化为事务数据库,然后即可利用传统挖掘算法进行挖掘。     

以客户为中心，建立紧密客户关系

从武汉钢铁股份有限公司对客户认识上的三次飞跃入手，从公司赢得客户的具体做法、与客户接触、处理客户的投诉、改进与客户的关系等四个方面论述了武汉钢铁股份有限公司以客户为中心，不断更新认识观念、改进服务技术、提高服务能力，从而赢得客户，与客户建立紧密的相互关系。     

Reciprocal Associations Between Adolescent Sexual Activity and Quality of Youth-Parent Interactions.

The authors examined differences in adolescents' relationships with their parents before and after adolescent first sexual activity. Participants were 13,570 members of the core sample of the National Longitudinal Survey of Adolescent Health (Add Health) Waves 1 and 2. Path analyses examined changes in parent-adolescent closeness, shared activities, and problem-focused interactions associated with changes in sexual activity separately for sons and daughters and for mothers and fathers. Race, religion, age, urbanicity, and parents' education were controls. Results confirm that increased problem-focused interactions and decreased parental closeness and shared activities both precede and follow adolescent sexual activity. Maintaining positive parental relations after adolescent first sexual activity is discussed as a means to reduce risks associated with sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)