查询词典 isomer

The optimum reaction conditions were: at present of acetic anhydride, a stoichiometric quantity of nitric acid, at room temperature for 40 minutes. Nitration of chlorobenzene gave a,50% yield of mononitro compounds, and an ortho-para isomer ratio 0.20 in product distribution of chlorobenzene mononitration.

结果表明：硅钨酸催化性能较好，催化剂载体以纳米二氧化硅最好，反应条件中醋酸酐用量是主要影响因素；SiW_(12)O_(40)~(4-)／纳米SiO_2催化剂具有强对位选择性：在醋酸酐存在下，氯苯与等当量的硝酸室温下反应40分钟，氯苯一硝化产物中邻／对硝基氯苯异构体的质量比达0.2，产率可达50％。

The results indicate that the imprinted polymers synthesized by methacrylic acid as functional monomer exhibite the best regioselectivity, yielding up to 49.6% pare and 44.1% ortho isomer of nitrotoluene.

结果显示分子印迹聚合物提高了甲苯的对位选择性硝化能力，并且以甲基丙烯酸为功能单体的分子印迹聚合物的对位选择性最好，邻对比为0.89。

FT-Raman and surface enhanced Raman spectra of leucine and isoleucine, the only isomer in proteinic amino acids, on the silver colloidal substrate are recorded.

报道了在蛋白质氨基酸中唯一一对异构体氨基酸——亮氨酸和异亮氨酸的FT-拉曼光谱和在银胶基底上的表面增强拉曼光谱。

Resolution of racemic drugs by lipase catalysis offers an excellent technology for the preparation of single-isomer chiral drugs in organic solvent.

在有机相中，脂肪酶催化消旋体的拆分，为制备单异构体手性药物提供了重要的技术手段。

With the need of pure isomer of racemic mixture increasing, more and more attentions have been paid to the chiral resolution membrane technology, which has been known as an energy-saving technology and considered as an easily scale-up chiral resolution technique.

手性拆分膜技术作为一种低能耗和易于工业放大的手性拆分技术，近年来随着单一手性物质需求的日益增长得到了广泛的关注。

The results show high selectivity when the temperature is controlled at 50 CC , and the nitrated reaction time is 90 mm, toluene is nitrated by using 95% nitric acid as nitrating reagent at the presence of acetic anhydride, 1.0g silicotungstic acid catalyst is calcinated at 300℃ for 1.5h. The o/p (ratio of ortho to paro isomer of toluene nitration) ratio is 0.89 in product distribution of toluene nitration, lower than 1.67 using sulfonitric acid as catalyst. The yield of products is 91.6%.

结果表明，在醋酐存在条件下，以CCl4为溶剂，以质量分数为95%的硝酸为硝化剂，反应温度控制在50℃，反应60 min， 1.0g经300℃焙烧1.5h后的硅钨酸催化剂，对甲苯表现出强的区城选择性，甲苯硝化产物o/p值（甲苯硝化产物邻位和对位异构体的质量比）达0.89，较硝硫混酸的1.67显著降低，产物收率达到91.6%。

The present invention concerns a compound having the formula a N-oxide form, a stereochemical isomer, racemic mixture, salt prodrug, ester or metabolite thereof.

本发明涉及具有式的化合物、其N-氧化物形式、立体化学异构体、外消旋混合物、盐、前体药物、酯或代谢物。

Comparisons between the experimental and computational IR spectra clarify the difference of the open- and closed-ring isomers, which indicate that it is possible to identify the tautomeric form of this diarylethene derivative using a highly selective infrared absorption band and the strong absorption at 1 705 cm-1 of the ring-closed isomer can be used in non-destructive readout by IR light.

通过红外吸收光谱表征了该光致变色二芳基乙烯衍生物在溶液中开、关环前后结构的变化，并采用理论化学计算方法研究了该化合物开、关环异构体的红外吸收振动特性。光致变色异构化过程可以通过红外吸收光谱的变化而识别。关环异构体在1 705 cm

Following resolution, the following steps are performed: reduce the isomer to an alcohol, react the alcohol with triphenylmethyl chloride, ozonalyze the resulting reaction product, reduce the ozonalyzed product to yield a diol and react the diol with a methane sulfonyl compound to form-3-2-{(methylsulfonyloxy}ethoxy-4--1-butanol methane sulfonate.

拆分后，进行下一步：将异构体还原为醇，使醇与三苯基甲基氯反应，臭氧化所得反应产物，还原臭氧化产物以得到一种二醇并使所述二醇与甲烷磺酰基化合物反应以形成-3-2-{(甲基磺酰基氧}乙氧基-4--1-丁醇甲烷磺酸酯。

Diltiazem is an important coronary vasodilating drug and contains two chiral centers while only the (2S, 3S)-isomer has the desired activity.

地尔硫卓是重要的心血管药物，在其分子结构中含有2个手性中心，可产生4个立体异构体，其中只有(2S， 3S)－异构体具有药理活性，因此其立体选择性合成具有很大的挑战性。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。