硝基置换

In this study, new benzo[l,2,3]thiadiazole derivatives were designed according to relationship of structure and efficacy. The 9 novel compounds were synsthesized with following reactions. The chlorine atom in 2-chloro-3,5-dinitro-benzoic acid as beginning raw material was substituted by 2-methylpropane-2-thiol, esterified then with bromoethane, reduced by iron powder and cyclized to obtain ethyl benzo[l,2,3]thiadiazole-7 after diazonation reation.

本论文根据苯并噻二唑诱导剂的构效关系设计了新的苯并噻二唑的结构，并合成了9个未见文献报道的化合物，合成步骤如下：采用2-氯-3，5-二硝基苯甲酸为起始原料，苯环上的氯原子被叔丁基硫醇置换，羧酸由溴乙烷酯化，硝基由铁粉还原，随后经重氮化关环生成苯并[1，2，3]噻二唑-7-羧酸乙酯。

Although scientists have not previously identified the precise connection between oxidation and neurodegenerative diseases, researchers from the US department of energy's Pacific Northwest National Laboratory and UCLA's David Geffen school of medicine have found that damage is due to a byproduct of oxidisation called nitration.

尽管科学家们之前并未确定氧化和神经退化疾病的精确联系，美国能源部太平洋西北国家实验室和加州大学洛杉机分校David Geffen医学院的研究人员们已经发现细胞破坏源于一种氧化作用的副产品硝基置换。

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。