环

Sodium cyclohexanoloxyacetate was synthesized by 1mol︰1.15mol of cyclohexyl sodium alcoholate to sodium chloroacetate at 135145℃.The reaction time was 2.5h and the yield was about 81%.The sodium cyclohexanoloxyacetate was acidified by HCl to get the intermediate product,2-cyclohexanoloxyacetic acid.

以摩尔比为1︰1.15的环己醇钠和氯乙酸钠为原料，在135145℃下反应合成了环己氧基乙酸钠，反应时间为2.5h，收率约为81%，再将环己氧基乙酸钠用盐酸酸化制得中间体环己氧基乙酸。

Our results are complementary to the earlier work by Law and co-workers. The photosensitivity is enhanced for the pigments with larger anilide ring.

首次考察了偶合基酰胺芳环共轭环扩大时光敏性的变化规律，发现酰胺芳环共轭环扩大时有所提高。

The electron- withdrawing groups in the anilide ring of the coupler moiety enhance the photosensitivity. Remarkable increase of photosensitivity was observed with Azo9, suggesting that conjugation effects drastically influence the photoconductive properties.

值得注意的是萘环上扩大一个咔唑环（Azo9，使偶氮染料的光敏性提高了几十倍，表明在萘环上扩大共轭环是提高偶氮染料光敏性的一个良好途径。

A novel endocyclic enamine cyclopentenone annulation was discovered and rationalized as an unusual Nazarov-type electrocyclization, which would have broad applications in the synthesis of natural alkaloids and other heterocycles.

我们在合成路线一、路线二中用的6-6元环系到7-5元环系的还原重排反应，在温和的酸性还原条件下即能发生，这说明在三尖杉碱的生物合成中6-6元环到7-5元环的还原重排步骤是非常有可能发生的；因此，我们的合成路线二中可认为是生物合成过程。

For the synthesis of NHC precursors, there are also several routes: condensation of glyoxal, amines and paraformaldehyde; alkylation of imidazole or monosubstituted imidazole with alkyl halide; annulation of ortho esters and 1,2-diamines; ring closure of hydrazines or amides with acetic anhydride; reduction of thiones with Na/K in THF.

关于N-杂环卡宾前体的合成途径主要有：乙二醛、伯胺和多聚甲醛的缩合反应；卤代烷与咪唑及其取代咪唑的烷基化反应；原甲酸酯与1，2-二胺的成环反应；肼或酰胺与酸酐的环化反应；用Na/K对环硫脲化合物的还原反应。

However, despite such categorical pronouncements as "…the above shows that the ring is not the fundamental system for associative algebra of double composition "found in [Vandiver,1939], semirings never became popular and the interest in them among algebraists gradually petered out, although it never died completely.

这些年来，半环被各类研究者所探究或者是在他们的本身及尝试从半群理论和环论中拓展研究方法，或者联系于各种应用。然而，尽管这种范畴的看法"…上面表明环不是最基本的系统对于双复合结合代数"（这句话出自[Vandiver ，1939]）。半环没有受到他们的欢迎和引起他们的兴趣进而逐渐淡化，尽管没有彻底的消亡。

The paper discusses the position relationship between the litter circles of torus and the section circle of sphere figured out the intersection of torus and sphere when the central axis of torus and sphere center in XOZ coordinate plane through coordinate transformation.

利用坐标变换使圆环中心轴与球心同在XOZ平面内，讨论了在该平面内圆环截圆与球圆的位置不相交、相切和相交时圆环面和球面的相交情况，并给出了判别圆环面、球面相交情况的流程图以及圆环面和球面相交实例。

To achieve high-performance PMSM position servo system, advanced control scheme, which is static precision, transient responses and self-adaptation and anti-disturbances, is needed in practice. Based on the analysis on the features and control principles of PMSM, this thesis established its math model using id=0 vector control method. Three close loops control system, which includes current loop, velocity loop and position loop, was built up. For position loop, the main feedback loop, we chose a new adapted-fuzzy CMAC intelligent controller, which includes self-learn ability of neural net and quick response merit of fuzzy controller. Finally, the author simulates PMSM position servo system by the simulink of matlab, an advanced computer simulation tool.

本文对PMSM的控制机理和特性作了较为深入的分析；建立了PMSM的数学模型，并采用了id=0的矢量控制策略；对控制系统组成及控制方式作了分析和比较，在此基础上建立了电流环、速度环和位置环的三闭环控制系统，对作为反馈主回路的位置环采用了模糊CMAC神经网络控制方法，该方法兼具模糊控制器的快速性和神经网络的自学习能力；构建了针对PMSM位置伺服系统的模糊CMAC控制器结构及其相应的算法；利用先进的计算机仿真工具（Matlab下的Simulink）对所提出的控制策略进行了数字仿真和分析；仿真和实验结果表明本文所提出的控制策略对PMSM位置伺服系统进行控制具有良好的鲁棒性能和快速性。

When the system starts, the speed outer ring saturats non-functional, the current inner ring plays a major role to regulate the starting current to maintain the maximum so that the speed linear change, to reach a given value; when it operates steadily, the speed negative feedback from the outer ring plays a major role ,to let the speed changes with the given speed voltage , at the same time the current inner ring regulates the armature current of motor adjustment to balance the load current.

该系统起动时，转速外环饱和不起作用，电流内环起主要作用，调节起动电流保持最大值，使转速线性变化，迅速达到给定值；稳态运行时，转速负反馈外环起主要作用，使转速随转速给定电压的变化而变化，电流内环跟随转速外环调节电机的电枢电流以平衡负载电流。

By using properties of scalar matrices over semirings,we generalize algebraic properties for the automorphisms of matrix algebras over commutative rings and obtain some algebraic properties for the automorphisms of matrix algebras over commutative semirings.

在这一章中，我们首先利用半环上常量矩阵的性质把环上矩阵代数的性质拓广到半环上，获得了交换半环上矩阵代数自同构的一些代数性质，接下来采用积和式的方法证明任意非负交换半环上n阶矩阵代数Tn的自同构的n次幂必为内自同构。

Shop assistant: Please check at the door.

店员：请您到门口柜台交费。

In the end, transportation of PAHs in the environmental matrix was preliminarily investigated and discussed according to PAHs data of soils and sediments from a certain region in Shanghai. The result indicated that there are two or more pathways on PAHs transportation in the environmental matrix.

最后，对上海特定地区内PAHs在环境介质中的迁移径途进行了分析讨论，结果表明上海市土壤和沉积物等环境介质中PAHs的迁移存在多种途径。