Co-Si多层膜的透射电镜研究

国家自然科学基金

Al_xGa_(1-x)As_ySb_(1-y)/GaSb的LPE生长与性质研究

其它基金

Environmental geochemistry and health of fluorine in Chinese coals

IEECAS SKLLQG

长白山生物圈保护区旅游的环境影响研究

生态旅游可以简单地定义为发生在那些具有独特的风景、特殊的生态学价值和具有纯粹自然性的受保护区域的旅游活动，也可以被理解为广义旅游的一部分，即可为自然和文化资源保护提供经济支持的一种旅游。根据生态旅游协会的定义（１９９１），生态旅游是一种前往自然区域以...

不同轮作施肥对土壤有机氮分解特征的影响

在各长期轮作施肥系统中,耕层土壤矿化培养过程的pH及剖面矿化势的变化,说明了长期不同的轮作和施肥方式引起土壤有机氮数量和性质的变化。pH变化具有一共同特征,在0~4 周,各处理间差异显著;而后期变化趋势趋于一致,向微碱性环境发展。各处理的剖面矿化势的变化反映了有机氮可矿化数量的改变。小麦连作施肥和苜蓿连作施肥均说明施用有机肥对土壤有机氮水平有较好的提高作用。粮豆轮作3 a对土壤供氮能力的提高作用大于粮饲轮作4 a和裸地处理。

Molecular characterization of beef liver catalase by scanning tunneling microscopy

Beef liver catalase molecules can stick tenaciously to the highly oriented pyrolytic graphite (HOPG) surface which has been activated by electrochemical anodization. The immobilized sample is stable enough for high resolution scanning tunneling microscope (STM) imaging. When the anodized conditions are controlled properly, the HOPG surface will be covered with a very thin oxide layer which can bind the protein molecules. Individual molecules of native beef liver catalase are directly observed in detail by STM, which shows an oval-shape structure with a waist. The dimensions of one catalase molecule in this study are estimated as 9.0 x 6.0x 2.0 nm(3), which are in good agreement with the known data obtained from X-ray analysis, except the height can not be exactly determined from STM. Electrochemical results confirm that the freshly adsorbed catalase molecules maintain their native structures with biological activities. However, the partly unfolding structure of catalase molecules is observed after the sample is stored for 15 days, this may be caused by the long-term interaction between catalase molecules and the anodized HOPG surface.