一种复合材料尖劈和接头端部安全性评估的新模型

笔者从尖劈尖端的弱式控制方程出发导出虚功原理 ,然后通过非协调元离散 ,得到一个基于位移的、分析尖劈尖端奇异性问题的特征方程。该方法与过去原有求解裂纹尖端近似场的有限元特征分析方法导出公式的出发点不同 ,并且采用的单元形式为非协调元 ,尖劈尖端邻域内的位移场假定没有采用奇异变换技术。通过求解特征方程获得奇性应力指数 ,并以此判断尖劈和接头的安全性 ,运用该方法对若干尖劈和接头进行安全性评估。所有的计算结果表明 ,笔者方法较原有方法使用的单元少而且精度高。     

我国应急体系建设中的问题探讨与对策

近年来,紧急突发公共事件在国内外频频发生,如何应对紧急突发事件是目前急需解决的问题.我国在这方面已经进行了一些研究,建立了初步的应急体制,取得了阶段性的成果.但普遍存在危机意识薄弱、预案编制存在漏洞、专业人才缺乏、应急协调机制不健全等问题.为了进一步健全应急管理,加强应急管理工作制度建设,必须强化应急教育和培训、加强应急管理人才队伍建设、建立通畅灵敏的应急管理信息系统等几项措施,从而切实提高我国的应急体系建设水平.     

关于危险废物处置项目投资营运模式的探讨

探讨了我国危险废物处置项目投资及营运模式，提出政府、企业共同出资建设，采用现代企业制度和市场化营运模式符合我国现阶段的国情。     

“绿水青山就是金山银山”理念实践模式与路径探析

“绿水青山就是金山银山”理念是习近平生态文明思想的重要内容，为推动经济高质量发展和生态环境高水平保护提供了根本遵循。本文在评估“绿水青山就是金山银山”理念实践进展与成效的基础上，从护美绿水青山和做大金山银山两个维度，研究提出11种实践典型模式，并基于不同经济发展水平和生态环境条件差异，提出4类区域转化路径。最后，提出推广“绿水青山就是金山银山”理念实践模式、优化“绿水青山就是金山银山”理念转化路径、完善“绿水青山就是金山银山”理念评价机制与技术能力、强化政策支持和引导等建议。     

城乡垃圾无害化资源化处理的探讨

本文针对我国城乡垃圾污染问题，以辽宁省盘山县为城乡代表，对城乡垃圾无害化、资源化处理进行了探讨。根据县城、场、乡、镇、农村排放垃圾的不同，因地制宜地提出了相应的处理模式，并对城乡垃圾无害化、资源化处理进行了效益分析。     

重塑经营者的激励机制

对于现代企业来说,如何激励经营者,充分发挥其潜能,为企业和股东创造出最大经济价值,成了债权人、股东、经营者等利益集团十分关心的问题。国家应建立和完善经营者的激励机制,企业应结合自身发展战略,重新设计经营者的薪酬计划,有效地推动经营者个人的行为表现,带领企业朝着整体战略目标迈进。     

Tour Level Mode Choice Analysis of Madison Area in Wisconsin

This study is to investigate what factors and how they affect tours （trip chains） behavior. The key issue is the understanding and definition of tour and tour level mode. Also, these definitions should fit for the data. A semi-home based tour definition is stated, and a competing mode based tour mode is defined. Based on the definition, this study used Madison Area Data from National Household Survey to estimate a MNL structured model. It is found that travel distance could be a positive factor for car mode. Meanwhile, the number of trips is also a positive factor for choosing car.     

Microbial phytotoxins as potential herbicides

Abstract

Microbes are sources of a diverse array of phytotoxic compounds. These compounds are generally structurally different from commercial herbicides, targeting different molecular sites of action within the plant. These novel structures and sites can be excellent leads for the discovery and development of safer synthetic herbicides. Microbial phytotoxins are often more environmentally benign than synthetic herbicides. Examples of phytotoxins from fungi (AAL‐toxin, cornexistin, cyperin, and tentoxin) with novel structures and sites of action are discussed. AAL‐toxin is toxic to a wide variety of weeds at very low dose rates. AAL‐toxin and many of its analogues kill plants by inhibiting a ceramide synthase‐like enzyme, causing rapid accumulation of free sphingoid bases that disrupt membranes. Cornexistin appears to be metabolically cnverted to an inhibitor of certain aspartate amino transferase isoenzymes. Its activity can be reversed by feeding aspartate and glutamate or with tricarboxylic acid cycle intermediates. Its activity is much like that of (aminooxy)acetate. Cyperin is a diphenylether phytotoxin that inhibits protoporphyrinogen oxidase, but does not kill plants by this mechanism. It appears to have other effects on porphyrin metabolism. Tentoxin is toxic by two mechanisms. It disrupts chloroplast development by inhibiting the processing of a nuclear‐coded plastid protein, and it also inhibits photophosphorylation by acting as an energy transfer inhibitor of coupling factor 1 ATPase. Other examples of phytotoxins from microbes with promise as herbicides will be mentioned.     

有机化合物动态定量结构——生物降解关系(QSBR)模型研究

本文通过分析一般ＱＳＢＲ模型应用的特点、不足和影响有机物生物降解的基本因素，指出ＱＳＢＲ模型应综合反映影响有机物生物降解的四个方面（以氯代芳香化合物为例）：氯代苯系物的摄入、氯代苯系物的诱导作用、毒性物质的形成和基础酶的缺乏。在此基础之上给出了动态ＱＳＢＲ的概念模式及方法学基础。     

清初“摊丁入亩”政策对环境的影响

清初“摊丁入亩”政策对清社会经济的恢复发展确实起到了促进作用,但同时对环境也构成了巨大威胁,引发了地表植被遭严重玻坏、自然灾害频繁、珍稀野生动植物大量灭绝等一系列环境问题。剖璞见玉,对今有史鉴作用。