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排序方式: 共有3398条查询结果,搜索用时 15 毫秒
981.
SONG Weiqun LUO Yueji CHI Song JI Xunming LING Feng ZHAO Lun WANG Maobin SHI Jiannong 《自然科学进展(英文版)》2006,16(10):1045-1050
The visual spatial attention mechanism in the brain was studied in 16 young subjects through the visual search paradigm of precue-target by the event-related potential (ERP) technique, with the attentive ranges cued by different scales of Chinese character and region cues. The results showed that the response time for Chinese character cues was much longer than that for region cues especially for small region cues. With the exterior interferences, the target stimuli recognition under region cues was much quicker than that under Chinese character cues. Compared with that under region cues, targets under Chinese character cues could lead to increase of the posterior P1, decrease of the N1 and increase of the P2. It should also be noted that the differences between region cues and Chinese character cues were affected by the interference types. Under exterior interferences, no significant difference was found between region cues and Chinese character cues; however, it was not the case under the interior interferences. Considering the difference between the exterior interferences and the interior interferences, we could conclude that with the increase of difficulty in target recognition there was obvious difference in the consumption of anterior frontal resources by target stimuli under the two kinds of cues. 相似文献
982.
几种基于基因组DNA的真菌分类技术研究进展 总被引:6,自引:0,他引:6
基于基因组DNA的真菌分类技术发展迅速。综述了DNA分子杂交技术,真菌线粒体DNA限制性片段长度多态性(m t RFLP)分析,随机扩增多态性DNA(RAPD)分析,rDNA序列分析,扩增片断长度多态性(amp lifiedfragm ent length polymorph ism,AFLP)在真菌分类和系统发育中的应用。 相似文献
983.
This paper puts forward a new variable step size LMS adaptive algorithm based on variable region. The step size p(k) in the algorithm varies with the variation of the region of deviation e (k) to ensure the optimization of the three performance objectives including initial convergent speed, trace ability of the time-varying system and steady disregulation. The paper demonstrates the convergence of the algorithm accompanied by random noise, 相似文献
984.
985.
In situ observation of C60(C(COOH)2)2 interacting with living cells using fluorescence microscopy 总被引:1,自引:0,他引:1
YE Chang CHEN Chunying CHEN Zhen MENG Huan XING Li JIANG Yaxin YUAN Hui XING Gengmei ZHAO Feng ZHAO Yuliang CHAI Zhifang FANG Xiaohong HAN Dong CHEN Long WANG Chen WEI Taotao 《科学通报(英文版)》2006,51(9):1060-1064
1 Introduction In recent years, studies on biological effects of thenanoscale materials have become the cornerstone of rapidly developed nanomedical and nanobiological technologies. Moreover, studies on the bio-effects when the different kinds of nanoscal… 相似文献
986.
PDF417纠错码原理及实现 总被引:2,自引:0,他引:2
为了促进PDF417这种高效率低成本的条形码在中国的深入研究和推广,介绍了Reed-Solomon纠错码原理和它在PDF417二维条形码中的应用方法.推导了在迦罗华域GF(929)内编译码方法,并通过实例具体说明.提出了一种适用于PDF417纠错编码和译码的查表方法,可以简单确定任意码字在GF(929)内所对应的本原元的幂次.运用该方法可以快速而准确地计算出纠错码生成多项式的系数列以及差错伴随式. 相似文献
987.
采用PCR技术从小鼠cDNA文库中扩增出编码caveolin-1和flotillin-1基因片断,通过TOPO载体将基因克隆到表达载体pEGFP,转化至大肠杆菌DH5α中,抽提、纯化后将重组质粒转入PC12细胞中表达,用TIRFM观察高K 刺激下胞内标记蛋白的动态分布情况.实验结果显示重组质粒caveolin-1-pEGFP和flotil-lin-1-pEGFP在PC12细胞中具有一定的功能,而且caveolin-1和flotillin-1在发挥功能时可能有一个向膜转运的过程. 相似文献
988.
Landslides and Slope Aspect in the Three Gorges Reservoir Area Based on GIS and Information Value Model 总被引:1,自引:0,他引:1
WU Caiyan QIAO Jianping WANG Meng 《武汉大学学报:自然科学英文版》2006,11(4):773-779
Slope aspect is one of the indispensable internal factors besides lithology, relative elevation and slope degree. In this paper authors use information value model with Geo graphical Information System (GIS) technology to study how slope aspect contributes to landslide growth from Yunyang to Wushan segment in the Three Gorges Reservoir area, and the relationship between aspect and landslide growth is quantified. Through the research on 205 landslides examples, it is found that the slope contributes most whose aspect is towards south,southeast and southwest aspect contribute moderately, and other five aspects contribute little. The research result inosculates preferably with the fact. The result of this paper can provide potent gist to the construction of Three Gorges Reservoir area in future. 相似文献
989.
滇藏民间商贸交流发展机制研究 总被引:1,自引:0,他引:1
周智生 《中央民族学院学报》2006,33(4):18-24
当代滇藏民间贸易发展的驱动机制、滇藏民间贸易面临的主要问题、滇藏民间贸易的发展前景、如何进一步构建促进其发展的机制等问题。需要认真分析和研究。研究表明。滇藏民间贸易不仅是促进云南和康藏地区区际经济联系的重要载体和发展动力,而且也是滇、藏、川、青等中国西部相邻民族省份间互动发展、共同促进对外开放的重要途径。 相似文献
990.