NPP distribution related to the terrains along the North-South Transect of Eastern China

Vegetation net primary productivity (NPP) is defined as the accumulative amount of organic matters per unit area and time, which is calculated from the difference between accumulative photosynthesis and accumulative autotrophic respiration by green plants. Since the NPP reflects the physiological and ecological characteristics of the plants and the interactive results of the environmental factors, it is an important index to evaluate a structure of ecological system, functional features and …     

Simulation of meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

The South China Sea (SCS) is the largest marginal sea in the northwestern Pacific. Several important water gateways exist around the SCS, such as Luzon Strait, Taiwan Strait, etc., that lie in the northeastern SCS, and others like Kalimantan Strait, Balawan Strait, etc., lie in the south. Luzon Strait connects the SCS and Pacific via the Philippine Sea, and its water exchange has significant impact on the interior circulations of the SCS[1]. Since direct observation data about the …     

《中图法》与中国特色

《中图法》是一部具有中国特色的、符合中国国情的学科发展简史。它的指导思想和中国的社会制度及执政党的理念有密切联系。它的学科分类和历次修订都是在这一框架下完成的。探讨这一特点,对今后修订《中图法》有一定的借鉴作用。     

改善西部生态环境 促进西部经济发展

恶劣的生态环境已成为21世纪制约西部经济发展的重要因素。阐述了良好的生态环境对西部经济发展的重要性，分析了西部生态环境的现状，并提出改善西部生态环境的对策和建议。     

我国与发达国家大学图书馆信息素质教育的比较

论述了信息素质和信息素质教育的内涵，分析和比较了美国、日本等国家与我国大学图书馆信息素质教育的现状，介绍了美国《高等教育信息素质能力标准》的主要内容，评价了它的作用和影响。在借鉴美国信息素质教育经验的基础上提出了我国大学图书馆信息素质教育发展的对策。     

我国土地利用研究现状分析

本文分析了目前我国在土地利用领域的研究现状 .认为 :当前我国在土地利用 /覆被变化研究是土地利用研究领域的重点 ,不仅在研究内容上注重土地利用变化的动态过程、强调其驱动机制的分析及其生态环境效应的反映 ,而且在研究方法上不断探索 ;同时 ,土地利用结构的合理化及土地的可持续利用为核心内容的土地利用优化配置 ,也成为部分学者土地利用变化研究的重要内容 .     

清代东北天花的预防及其嬗变

天花流行对清朝的统治造成极大危害,东北虽处边塞但仍未能幸免。清代东北天花的预防经历了逃疫、局部种人痘、大面积种牛痘三个阶段的变化,随着医疗技术的提高,天花逐渐被遏制。清代东北的天花预防工作及其嬗变过程,见证了东北地区的医疗近代化。     

“健康中国2030”的机遇与挑战

 健康中国已上升为国家战略。介绍了《"健康中国2030"规划纲要》的主要内容,剖析了影响健康中国建设的主要问题,并提出了相应的应对措施。指出健康中国的建设关键在落实,在于政府主导、多部门合作、全社会参与的合作机制的建立。     

中国杉木害虫名录（二）（昆虫纲：鞘翅目）

通过调查和查阅文献资料，整理了危害我国杉木的害虫名录（二），主要包括昆虫纲（ Isecta）鞘翅目（ Co-Leoptera）害虫18科101属142种。并列出每种害虫的中名、学名和分布省份，为杉木的鞘翅目害虫的监测与综合治理提供依据。     

Effect of Ce addition on hot tearing behavior of AZ91 alloy

A small amount of cerium (below 1.0 wt%) addition to AZ91 alloy have been investigated on the hot tearing susceptibility (HTS) at a cooling rate of 1.5Ks^?1. The HTS increased to a maximum value with a cerium addition of 0.6 wt% and then decreased to a stable status as cerium was gradually added. Due to high chemical activity, cerium into the melts can react with aluminum to form an Al₁₁Ce₃ intermetallic compound. X–ray diffraction results also confirmed the existence of Al₁₁Ce₃. The Al₁₁Ce₃ increased with the presence of the needle-like and block morphology. As cerium levels increased, the amount of Mg₁₇Al₁₂ decreased. The variations between Mg₁₇Al₁₂ and Al₁₁Ce₃ resulted in a similar normal distribution of the HTS in AZ91 alloy. The findings were further verified through the microstructure evolution and the surface morphology of fracture.