Antifungal activity of phenolic monoterpenes and structure-related compounds against plant pathogenic fungi

The aim of this work is to explore the possibility of using the phenolic monoterpenes (PMs) as leading compounds with antifungal activity against plant disease. The in vitro antifungal activities of carvacrol and thymol against seven kinds of plant pathogenic fungi were evaluated on mycelium growth rate method, and the results showed that carvacrol and thymol exhibited broad spectrum antifungal activity. Structure requirement for the antifungal activity of PMs was also investigated. The preliminary conclusion was that phenolic hydroxyl and monoterpene were basic structures for the antifungal activity of PMs, and the position of phenolic hydroxyl showed less effect. Ester derivatives of carvacrol and thymol were more effective than carvacrol and thymol against plant pathogenic fungi. We suggested that carvacrol, thymol and their ester derivatives could potentially be used as new fungicide leading compounds.     

离轴微粒场全息术中记录介质分辨率要求

本文从离轴微粒场全息记录光路的一般模型出发,导出了离轴微粒场全息术中记录介质分辨率要求的普遍公式。讨论了三种典型形状微粒对记录介质的分辨率要求。结果表明,除了参考光的倾角外,微粒的尺寸和参、物光的波前曲率差及微粒重心偏离光轴的距离也都是影响记录介质分辨率要求的主要因素。     

管理信息本体需求的谓词演算有限集构造

由于管理信息需求的不确定性、多样性和动态性,管理信息系统（包括ERP）的开发一直被认为是一项高风险的投资项目．通过管理信息本体的研究,构建基于本体需求的管理信息本体描述框架及其谓词演算集,无疑可以进一步降低管理信息系统的开发成本,缩短开发周期,提高开发效率,并且易于维护,从而延长管理信息系统的生命周期．     

昆虫飞行的高升力机理

对近年来关于昆虫产生非定常高升力的研究进行了综述和归纳.这方面的工作对生物学研究和微型飞行器等微型机械的仿生设计有重要意义.研究表明:果蝇等昆虫翅膀的拍动运动可产生很大的非定常升力,其平均值是定常值的2~3倍,足够平衡昆虫的重量,并有较大的富余用于机动飞行;产生高升力有三个因素:一是拍动开始阶段翅的快速加速运动,二是拍动中的不失速机制,三是拍动结束阶段翅的快速上仰运动.人们从能耗的角度考察了这些非定常高升力机制的正确性和可行性.当作悬停飞行的果蝇用以上机制产生平衡其重量的升力时,其比功率(支持单位身体质量所需的功率)约为29W/kg, 生化/机械效率约为17%. 这些值与人们基于对昆虫肌肉力学特性的研究所预估的值接近.果蝇前飞时,其比功率随速度变化的曲线是一J形曲线,而不是象飞机或鸟的那样是一U形曲线;这与人们基于昆虫新陈代谢率的测量数据所推断的结果一致.对于蜻蜒等(功能上)有前、后两对翅膀的昆虫,有以下初步结果:翅的下拍主要产生升力,上挥主要产生推力;下拍时的平均升力系数可达2~3,十分大,上挥时的平均推力系数可达1~2, 也很大,它们主要由非定常效应产生;前、后翅的相互干扰并未起增大升力和推力的作用,反而有一定的不利作用.      

The Solvency II square-root formula for systematic biometric risk

In this paper, we develop a model supporting the so-called square-root formula used in Solvency II to aggregate the modular life SCR. Describing the insurance policy by a Markov jump process, we can obtain expressions similar to the square-root formula in Solvency II by means of limited expansions around the best estimate. Numerical illustrations are given, based on German population data. Even if the square-root formula can be supported by theoretical considerations, it is shown that the QIS correlation matrix is highly questionable.     

中国硒研究历史回顾（上）

过去50年中,中国微量元素科学和营养科学中最重要的发现,就是认识了硒对人体健康的重要性。在诸多微量元素中,没有哪一个元素能像硒那样对人类产生如此深刻而又广泛的影响。从硒的生物必需性、硒的生物效应两面性、硒的抗癌性、硒的延寿作用及富硒产品开发五个方面回顾了中国的硒研究历程。     

基于状态空间的武器装备作战需求模型

以武器装备作战需求为分析对象,构建了数量与战技性能的状态空间和一般作战流程,描述了基于跳跃强度和状态概率的作战需求表达式,解决了作战任务与武器装备之间的映射规则问题。     

一种应用于量子数据压缩的幺正变换生成方法

提出了一种两类正交基矢按照特定要求相互转换的幺正变换生成方法. 特定要求为第一类基矢中特定的四种典型基矢经幺正变换后, 第三个量子比特特定为|0>, 而四种非典型基矢经幺正变换后, 第三个量子比特为|1>. 将该幺正变换应用于量子数据压缩, 准确度达到0.942. 该方法的提出为量子压缩和解压缩的实现提供了基础, 对于其他要求特定对应关系的幺正变换的生成具有借鉴意义. 关键词： 幺正变换 正交基矢 特定要求 量子压缩     

Area requirement of graph drawings with few crossings per edge

In this paper we study how to compute compact straight-line drawings of planar graphs with a limited number of crossings per edge. We prove that every outerplanar graph can be drawn in $O(n\log n)$ area using a sub-linear number of crossings per edge, and that for any given number $\epsilon >0$, every outerplanar graph admits an $O(n^{1+\epsilon })$ area drawing with $O(n^{1?\epsilon })$ crossing per edge. The drawing algorithms run in linear time and can be also generalized to another meaningful sub-family of series–parallel graphs with bounded vertex-degree.     

家庭化学小实验的设计及实验策略

巧妙地设计家庭化学小实验,并指导学生记录实验日记、组织实验沙龙,对激发学生学习化学的兴趣、提高实验教学效果有着积极的作用。