果蝇唾腺染色体观察实验教学的改革与探索

果蝇唾液腺染色体观察实验中,传统的方法因为种种原因效果较差。根据长期的教学实践,对该实验作了一些改革与探索。实践证明,改革后实验材料易获得,步骤简洁,所制装片清晰,取得较好的效果。     

中国北方草原区城市呼和浩特市域野生种子植物多样性编目

依据１９９６ 年夏季采集的标本，经鉴定确认：呼和浩特市域现有野生种子植物计１７２种，隶属１２３ 属、３７ 科．按生物多样性编目的要求分种进行了描述，为植物区系和群系（Ｆｌｏｒａａｎｄ Ｆｏｒｍ ａｔｉｏｎ）的分析奠定了基础．     

热处理对PLLA/PDLLA共混物冷结晶行为的影响

采用差示扫描量热法(DSC)和原子力显微镜(AFM)研究了热处理对左旋聚乳酸(PLLA)及其与消旋聚乳酸(PDLLA)1∶1共混物冷结晶行为的影响。结果表明,热处理后PLLA结晶速率的加快是通过增强成核过程来实现的;冷却速率越慢,成核效应越显著,PLLA的结晶速率则越快。相比于PLLA,PLLA/PDLLA共混物的成核效应却表现出对冷却速率不敏感,与非结晶性PDLLA阻碍了热处理过程中局部有序结构的形成有关。     

扎龙水禽栖息地生态脆弱性评价

根据扎龙珍稀水禽栖息地生态环境的特点,以生物指标、环境指标、景观结构指标和人类活动指标作为评价指标。利用层次分析法分配各指标权重,通过模糊综合评判模型运算和隶属度分析,将扎龙水禽栖息地生态脆弱性分为极度脆弱、高度脆弱、中度脆弱、一般脆弱和不脆弱5个等级,研究结果为该区域生态环境可持续发展提供科学依据。图1,参18。     

A classification of aquatic plant communities within the Nothern Rocky Mountains

A synecological study of aquatic macrophyte plant communities was conducted across northern Idaho and western Montana during the summers of 1997, 1998, and 1999. A total of 111 natural and man-made water bodies were sampled based on a stratification of environmental variables thought to influence plant species distribution (i.e., elevation, landform, geology, and water body size). Plant species foliar cover data were used to develop a hierarchical, floristic-based community type classification with TWINSPAN and DECORANA software. Six planmergent (conspicuous portion of vegetative plant body on the water surface) and 24 submergent (vegetative plant body found primarily underwater) community types were identified. Multivariate analysis indicated that all community types displayed significant differences in plant species composition, and the Sorensons floristic similarity between communities averaged 10% for planmergent and 8% for submergent types. Canonical correspondence analysis was used to inspect relationships between abiotic factors and plant species abundance. Results of this analysis indicated some relationships between species distributions and abiotic factors; however, chance introduction of plant species to water bodies is a process considered to be equally important to the presence of the community types described.     

金属眼镜架镍析出量检测技术研究

眼镜作为一种日用消费品,具有一定的视力矫正和保护作用,被越来越多的人所使用。镍是一种对人体有害的重金属元素,被广泛应用于金属眼镜架的生产制造工艺。介绍了金属眼镜架中镍元素的危害,分析了国内外金属眼镜架镍析出量相关标准及法规的现状。阐述了金属眼镜架镍析出量检测的基本原理和方法,重点介绍了眼镜架磨损试验和人工汗液腐蚀试验过程。最后对金属眼镜架镍析出量检测技术的主要发展趋势和方向做出了预测。     

BL Lac天体的X射线辐射机制测试

以Sambruna选取的52个BL Lac天体为测试样本,对HBLs和LBLs的αx,fx/fr,αox和复合谱指数间的关系作了初步分析,结果表明两个子类有不同的特性,支持其具有不同X射线辐射机制的假说.