类并

The reaction of polyfluoroalkyl iodides with 4-pentenoic acids initiated by sodium dithionite was realized to give polyfluoroalkyl substituted lactones.

我们研究了多氟烷基碘代烷与4-戊烯酸类化合物等在连二亚硫酸钠引发下的反应，得到了氟烷基取代的内酯化合物，我们将该反应称为氟烷基化内酯化反应；并建立了一个利用该反应合成含氟内酯的新方法，首次利用氟烷基化内酯化反应进行高立体选择性双环含氟内酯及手性含氟内酯等的合成，已合成含氟内酯新化合物50余种。

The dollar sign within the class is just a simple dollar sign and contains no special meaning within it.

美元类内签署的只是一个简单的美元符号，并包含内部没有特别的意义。

Furthermore, the Matrix Dominating Set problem and some research directions on dominating problem were also introduced.

文中对VDS和EDS问题进行了分类，给出了每类问题的具体定义及其相关算法介绍，此外还对矩阵支配集问题进行了简单介绍，并提出了支配问题研究中值得关注的几个方面。

In chapter 2, the contents of loureirins in the roots, stems and leaves of Dracaena cochinchinenis were analyzed by HPLC. On the other hand, using the preparation chromatography technology, five compounds were isolated from the leaves of Dracaena cochinchinenis, their structures were identified by means of spectral and chemical methods. They are steroidal saponins.

第二章主要是利用HPLC技术对剑叶龙血树根、茎、叶中龙血素成分的分析与探讨，并利用制备色谱等技术对剑叶龙血树叶子组成成分进行了分析、研究，得到化合物5个，经波谱鉴定，这5个化合物均是幽体皂贰类化合物。

Apparently, they couldn't formally enroll me until the next summer, because I had to go to summer camp before I could enter ROTC classes, but signing a letter of intent was enough for the draft board to waive my induction date and give me a 1-D Reservist classification.

显然，在下个暑假前，他们还不能正式录取我，因为在参加后备役军官训练军团前我得去参加夏令营。但签署一封意向书就足以让征兵委员会同意取消我的新兵报到，并把我列为预备役1-D类。

Such medicines are kept in drawers and are dispensed by the druggist, even aspirin.

这类药物存放在抽屉里，并配发的药剂师，甚至阿司匹林。

As to how to avoid weaknesses of these two operators, scholars have made unremitting efforts. One of the most famous is the French mathematician Sablonniere P, who introduced and studied a kind of new quasi-Bernstein interpolation operators in 1992. This kind of operators have given dual attention to the Lagrange operator and the Bernstein operator merit, and have avoided the twos deficiency.

对于这两种算子如何扬长避短，学者们做了不懈努力，其中最为著名的是法国数学家Sablonniere P，他于1992年引入并研究了一种新的拟Bernstein插值算子B上标(k 下标 n，，这是一类介于Lagrange算子与Bernstein算子之间的拟插值算子，这类算子兼顾了Lagrange算子与Bernstein算子的优点，克服了二者的不足。

We compared this two model and found that the two model is coincident when dual relation was symmetric.

接着我们又用前继邻域代替等价类建立了另一个准一般关系下模糊粗糙集模型，并把两种模型进行比较，指出当二元关系满足对称性时两种模型是一致的。

One-time fertilization at present rate did not have effects on nitrogen nutrient in water nor duckweed productivity.

以目前剂量施肥一次对水中氮类营养及浮萍生产力并无效应。

Dumont publishes daily newspapers and magazines, literature and non-fiction books; it's art department is regarded as one of the best in Europe since most of the art books and catalogues are created and produced in close collaboration and ongoing consultations with the artists.

DuMont出版社发行日报，杂志，文学及专业类书籍，其艺术书籍部门是欧洲同类部门中最优秀的。在那里，绝大部分的艺术图书及画册都是在与艺术家进行密切沟通后设计并制作的，有些则更是同艺术家直接共同工作的结果。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。