作用中心

Methods: Stomatological department and its medical staff in medical institutions in Chaoyang District were studied by questionnaire.

目的：了解北京市朝阳区医疗机构口腔科及其医务人员基本情况，明确社区卫生服务中心在牙防工作中的作用。

The grafting is believed to take place principally through the active centers which are formed on the cellulose substract by the action of eerie ion.

可以认为，接聚反应的发生主要是通过铈离子与纤维素作用在纤维素上生成活性中心。

The copper center was situated in a distorted square pyramidal (4+1) CuN3X2 coordination geometry with terpyridine acting as an equatorial tridentate ligand.

在配合物中，中心铜原子的配位环境为变形四为锥，并通过分子内和分子间的C-H…C1和C-H…O氢键作用形成三维梯状结构。

Compared with the catalytic behaviors of the reference catalysts, CpTiCl〓 and n-CpTiCl〓, we could identify that the pendant ethereal group played an important role in this selective trimerization process.

将它们的催化性能与CpTiCl〓、n-CpTiCl〓比较，可以确定，氧对钛活性中心的配位对乙烯三聚反应起重要作用。

By comparing the catalytic behavior of S3/MAO and S8/MAO, a conclusion could be drawn that the coordination of the sulfur atom to the titanium center of the active species was essential for ethylene trimerization.

通过比较S3与S8不同的催化性能，可以认为，硫原子对钛活性中心可能存在配位，而这一配位对乙烯三聚反应起重要作用。

HTERT is expressed in cancer cell lines despite promoter DNA methylation by preservation of unmethylated DNA and active chromatin around the transcription start site.

人端粒酶逆转录酶是一种核糖核蛋白酶，由端粒RNA和端粒酶蛋白组成的一种特殊逆转录酶，在激活端粒酶的过程中起限速作用，能以自身RNA为模板合成端粒序列以稳定端粒长度使细胞获得永生，也是人类端粒酶的活性中心，其表达是端粒酶活化的必须前题［2～4］。

Mount Tai plays a very important role in the case and makes the positive and minus extremes of vertical velocity in the upslope and lee, respectively. Meanwhile it affects the distribution of rain water and cloud water.

地形在此回流暴雪过程中，通过其强迫的、分别位于迎风坡和背风坡的正负垂直速度中心，对降雪起明显的增幅作用，同时对雨水和云水分布产生影响。

By the study of the relationship between vegetation and spatial characteristics of UHI, the mainly spatial characteristics of UHI has been analyzed and it was:(1) The terrain of the suburbs is higher than the urban region, the gradient of the terrain height is small, and this geomorphological featrue is conducive to assemble of the heat, the UHI phenomenon of Changsha is obvious especially in the summer night;(2) The UHI distribution is similar to the outline of the urban construction. The LST of urban is 3-5℃ higher than the flat low areas close around the city, and 6-8℃ higher than further areas. The region which has the most obvious UHI phenomenon is the region surrounded by the second city ring road, and the UHI phenomenon gradually weakened from the city centre to suburb;(3) The impact of geomorphological character to UHI is notable, the relationship between vegetation index and UHI is Anti-related, it was indicated that the improvement of the vegetational status is very important to the elimination of UHI phenomenon, the implementation of the urban green land planning can reduce UHI effect.

通过分析长沙城市地区的土地覆盖、植被绿地状况与热岛空间分布状况的关系，揭示出研究区域UHI主要特征为：(1)从研究区域地表覆盖图发现，长沙市城区四周均有相对地势较高的山地，但地形梯度不大，接近四面环山的地貌特征，容易造成城区的热量聚集，有利于城市热岛效应的形成，使得长沙城区存在明显的热岛分布；(2)UHI分布与城市结构的轮廓相一致，长沙城区与地势相对平坦的近郊区的地表温度差异为3~5℃，与地势较高的周边远郊区的地表温度差异为6~8℃，长沙城区热岛效应与城市规划呈对应关系，热岛效应最显著的区域为二环线内，并从中心沿三环逐渐向郊区减弱；(3)地表覆盖类型对UHI的效应明显，长沙地区植被绿地状况与UHI呈现明显反相关分布，揭示出植被绿地对降低UHI具有重要的作用，大范围的绿地建设能有效降低UHI。

In the reasonable drug molecular design,analyzing the conformations of the substrate without three-dimension structure and confirming its active conformation are very important to illustrate the spatial shape and active site of target enzyme. The active conformation of protoporphyrinogen IX substrate of protoporphyrinogen oxidase has been established using the Distance Comparisons DISCO method. In this paper, four different conformational molecules of Protogen IX and crystal molecule of diphenylethersAF are analyzed by comparing their geometry parameters. The results show the lower energy active conformation from the DISCO model is more reasonable.

在合理药物设计方法中，当靶标酶的三维结构未知时，对其底物进行构象分析，特别是确定其活性构象，对阐明靶标酶活性中心的空间形状和作用位点具有十分重要的意义我们曾利用距离比较法确定了原卟啉原氧化酶的底物—原卟啉原IX的活性构象，本文从构象分析的角度对4种不同构象的原卟啉原IX分子与二苯醚类分子的晶体学构象进行了几何参数的比较和分析，结果进一步证实了距离比较法所确定的活性构象更为可靠

Logistics is the headspring of the third profits, so how to scoop out the logistics potential

物流配送中心现代商品流通中的作用极大，它通过对商品的运输、保管

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。