等环的

Low melting point, low viscosity of the mixtures with alicyclic epoxy resins, long applicable period, high heat-resistance of the cured material and excellent electrical properties at high temperature, MHHPA is widely used for impregnating electrical coils, casting electricity components and sealing semiconductors, e.g.

MHHPA是炮炼凝固型酸酐类凝固剂，关键用于电气及电子方面，它拥有熔点低、与脂环族环氧松脂合成的默契物粘度低、适用期长、凝固物的耐热性高、高温电机能好等长处，可用于电气设备线圈的浸渍及电气元件的浇铸和半导体的密封，如户外绝缘子、电容器、反光二极管等、数码管等。

In 1977, Nicholson introduced the concept of clean rings as follows: A ring R is said to be clean ring if every element of R is the sum of an idempotent element and an invertible element.

Nicholson引入了一种新的环类，即所谓的clean环：一个环$R$被称为clean环，如果$R$中的任意一个元素均可以表示成R中一个幂等元和一个单位和的形式。

We focused the study on the synthesis methods of quinoxaline, nitration of its aromatic ring and chlorination of its heterocycle. In this paper, we thought about environmental protection, the cost of material, the feasibility of industrialization, workup easily, and obtained 2,3(1H,4H)-quinoxalinedion, 6-nitro-2,3(1H,4H)-quinoxalinedion, 6,7-dinitro-2,3(1H,4H)–quinoxalinedion, 2,3-dichlo- roquinoxaline, 6–nitro-2,3-dichloroquinoxaline,and 6,7- initro-2,3-dichloro-quinoxaline. A more reasonable, easily, efficient and simple reactive route to synthesize above-mentioned compounds was developed by systematically investigating the yield, the purity and physical character of intermediates.

本文针对喹喔啉及其芳环硝化、杂环氯代的合成进行研究，主要考虑了环保性、原料成本、产业化的可行性、反应操作的简便性等问题，获得了2，3(1H，4H)-喹喔啉二酮、6-硝基-2，3(1H，4H)-喹喔啉二酮、6，7-二硝基-2，3(1H，4H)-喹喔啉二酮、2，3-二氯喹喔啉、6-硝基-2，3-二氯喹喔啉和6，7-二硝基-2，3-二氯喹喔啉等六个中间体，考察了反应产物的产率、纯度和性状等因素，得到了更为合理、方便、实用、简洁的可供产业化的合成路线。

Cytochrome P450 BM-3 (CYP102) from Bacillus megaterium catalyzes the subterminal hydroxylation of long-chain fatty acids (C12 to C20) at the positions ω-1,ω-2,ω-3 and the epoxidation of unsaturated fatty acids. Artificial mutants of P450 BM-3 also hydroxylate substrates like short-chain fatty acids (C8 to C10), alkanes, cycloalkanes, heteroarenes and polycyclic aromatic hydrocarbons, which offers potential applications in the pharmaceutical industry, environmental measurement and bioremediation and chemical industry.

细胞色素P450BM-3来源于Bacillus megaterium，能催化长链脂肪酸C_(12-C_(20)的次末端(ω-1，ω-2，ω-3)羟化及不饱和脂肪酸的环氧化，其突变体催化的底物拓展到中链的脂肪酸C_8-C_(10、烷烃、环烷烃、杂环烃、多环芳烃等，因此在医药工业、环境检测和修复及化学工业具有广阔的前景。

The main characteristics include: the quiet Sun corona has a rapid response to the flare heating, within 2 second the corona temperature increases nearly one order of magnitude, but later such increase becomes very slowly; the downward velocity at early stage of impulsive phase is too small to be negnected; chromospheric evaporation made by conduction shows some intensely, the maximum evaporated velocity may be as large as 1000 km/s; the chromospheric condensation appears just when the chromospheric evaporation takes place and its place always coincide with that of transition region in the early stage; the maximum of chromospheric condensation occurs also in the early stage of impulsive phase, at which the density in condensation may be larger two order of magnitude than that of surround and the downward velocity may be as large as 100 km/s; after the maximum of chromospheric condensation, its strongth decreases gradually but its width becomes greater with time and have a tendency to transport into deep chromosphere; the front of chromospheric condensation heats atmosphere obviously and the temperature in the chromospheric condensation is higher than the original case; the downware velocity of transition region may be greater than 100 km/s at the early stage; when the evaporated material collide at the top of loop, the densityand the presure there increase rapidly, which result in the formation of a shock wave; and so on.

在改善色球辐射损失和精确分辨过渡区的基础上，通过联立求解连续性方程、动量方程和能量方程，构造了一维磁限制性耀斑环在热沉积作用下的大气动力学模型，获得了耀斑热模型下脉冲相早期较为细致的大气演化理论图象，其主要特征是：耀斑对宁静日冕的加热相当迅速，仅2秒钟日冕温度增加即达一个量级，之后日冕温度增加缓慢；脉冲相早期日冕向下速度很小，几乎可以忽略，热传导驱动色球蒸发，其过程较为激烈，蒸发极大速度可达到1000km/s；色球压缩区与色球蒸发几乎同时形成，且在早期其位置总是与过渡区位置重合；色球压缩极大发生在脉冲相早期，其时密度可高于周围约2个量级，向下速度可超过100km/s；色球压缩极大后，其强度逐渐减弱，但宽度明显增大，且渐渐脱离过渡区往色球传播；压缩区内物质温度要高于原先的大气温度；过渡区下降在脉冲相早期相当迅速，可超过100km/s；当蒸发物质在环顶高速相碰时，环顶的密度、压力迅速增大，且温度也有所增加，导致形成激波，其波面以每秒上百公里的速度自环顶向下传播；在脉冲相前期，日冕软x辐射对色球的加热作用可以忽略；等。

Butadiene was polymerized to some extent in the presence of binary catalyst system NdCl33iPrOHAlEt3 in toluene and the allylchloride was then added to the solution in order to cyclize the formed polybutadiene and cyclopolymerize the unreacted butadiene monomers.

采用NdCl3·3i－PrOH－AlEt3稀土催化剂进行丁二烯的顺式聚合，在聚合过程中引入烯丙基氯，进行分子内环化反应以及单体的环聚反应。考察了稀土催化剂用量、n／n（AlEt3）、环化时间、反应温度、单体浓度等对环化反应的影响，并对产物进行了红外光谱、核磁共振光谱的表

In this dissertation, two series of rare earth initiators: rare earth tri (2, 6-di-tert-butyl4-methylphenolate) and rare earth calixarene complex have been developed to ring-opening polymerize 2, 2-dimethyltrimethylene carbonate, trimethylene carbonate and ε-caprolactone at mild conditions. Both the polymerization features and mechanisms are discussed in details.

本论文为环碳酸酯、内酯的开环聚合开发了两类新型低毒性稀土催化剂：三(2，6-二叔丁基-4-甲基苯氧基)稀土配合物和对叔丁基杯芳烃稀土配合物，都可以在温和的反应条件下单组分引发2，2-二甲基三亚甲基环碳酸酯、三亚甲基环碳酸酯和ε-己内酯聚合，合成各种分子量的均聚和共聚材料，考察了催化剂结构、聚合条件等对聚合的影响，深入研究了聚合机理。

Current products are: Mat O ring seal suction cups water polo Washers Washers piece lamp set of silicone rubber ear pads nail dust cover jacket sealing rings ring.

现生产的产品有：脚垫 O环水球密封圈吸盘华司垫圈矽胶片灯头套胶钉垫片耳塞防尘套护套套环止水环等。

Results The main structure of the left ventricle in canine was composed of the mitral complex、aortic valve、falsetendons and so on,among them the mitral complex was included in the mitral ring and valve,chordae tendinease and papillary muscles;the circle of mitral ring was 49.16±10.00mm,the average heights of inside and outside valves were 14.28±3.14mm,9.27±1.99mm,respectively,the breadth were 25.74±5.21mm、21.50±6.33mm;the average number of chordae tendineass was 16.72±2.76;the average number of left ventricular false tendon was 4.69±3.38:the circle of aortic valve ring was 34.55±8.00mm,the average heights of left、right and back aortic valves were 6.85±1.76mm、7.19±1.75mm and 7.52±1.79mm.

结果：犬心左心室主要结构有二尖瓣复合体、主动脉瓣、假腱索等，其中二尖瓣复合体由瓣环、瓣膜、腱索、乳头肌构成；二尖瓣瓣环周径为49.16±10.00mm，内侧瓣、外侧瓣的高度分别为14.28±3.24mm、9.27±1.99mm，其宽度分别为25.74±5.21mm、21.50±6.33mm；腱索总数平均为16.72±2.76条；假腱索总数平均为4.69±3.38条；主动脉瓣瓣环周径为34.55±8.00mm，左瓣高度、右瓣高度和后瓣高度分别为6.85±1.76mm、7.19±1.75mm和7.52±1.79mm。

This paper introduces a kind of wind power ring for cleaning contamination on insulator surface in power system, which consists of a insulation ring, the bowls moved by wind, brush ring and scraper.

介绍一种用于电力系统清扫绝缘子表面污垢的风力清扫环，它由一个绝缘环和风力推动碗、毛刷环、刮板等组成。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。