排序方式: 共有28条查询结果,搜索用时 15 毫秒
1.
2.
A successful separation of prostaglandius E2 , F2a,15 (R) -15Me-F2a, and 15 (S) -15Me-F2a as p-nitrophenacyl bromide esters was attained by high performance liquid chromatography (HPLC) by using a micro column packed with Waters μ-Porasil. The esters were prepared by derivatization. All separations were accomplished with acetonitrile: dichloromethane (4 :1, v/v) . Significant results were obtained in the selected conditions. 相似文献
3.
DNS-Cl与蛋白质或多肽的α-氨基反应后,用酸水解,生成有萤光的DNS-氨基酸,其检出灵敏度比FDNB法(Fluoro dinitrobenzene)高100倍。但此法是在105°~110℃下用5.7NHCl水解,因此不能区别Gln与Glu,Asn与Asp,并且水解时Trp被破坏。另外在用聚酰胺薄膜鉴定DNS-氨基酸时杂点比较多,有时难以鉴别。现在采用的DABITC法测末端比DNS法优越。 (2)材料: dansyl—chloride;2.5mg DNS——Cl溶于1ml丙酮中。 0.1M NaHCO_3双蒸水溶液. DNS-玻璃管(5×0.5cm直径),于500℃处理. 干燥器,45℃热板和105℃烘箱及油泵. 相似文献
4.
天然檀香是人们喜爱的一种高级香料。其香气甜润而富有传统的东方香型特色。由于天然檀香的产量少,价格昂贵,而且提炼天然檀香的檀香木来源日益减 相似文献
5.
6.
In this article, we study the large time behavior of the 3-D isentropic compressible Navier-Stokes equation in the partial space-periodic domains, and simultaneously show that the related profile systems can be described by like Navier-Stokes equations with suitable"pressure" functions in lower dimensions. Our proofs are based on the energy methods together with some delicate analysis on the corresponding linearized problems. 相似文献
7.
控制反应条件,热分解三苯氧基膦臭氧加成物(Ⅱ)产生单线态分子氧,其产率由70%提高到98%,同单线态氧的探针化合物α-蒎烯反应,得到单一的“ene”型产物,松香芹醇(pinocarveol)。同6-羟基-1,4-顺,顺-环辛二烯(Ⅰ)反应占优势的过程也是“ene”反应,分离出还原产物5,8-二羟基-1,3-顺,顺-环辛二烯(Ⅲ),以及(Ⅲ)的热重排产物6-羟基-4-顺-环辛烯酮(Ⅳ),这同用光敏氧化的方法氧化(Ⅰ)得到的结果相一致。通过构型分析,说明了化合物(Ⅰ)同单线态氧作用,通过协同的“ene”反应进行,使分子轨道相互作用不利的[π4s+π2s]加成过程被抑制。 相似文献
8.
9.
10.
基态SiCO体系的分析势能函数 总被引:6,自引:3,他引:3
在从头计算的基础上,对基态SiCO体系的全势能表面用多体项展式方法进行优化,确定了分析势能函数.该势能函数准确再现了基态SiCO(X3Σ-)和SiOC( X3Σ-)的线性结构和能量,正确反映了SiCO(X3Σ-)和SiOC(X3Σ- )异构体的离解通道. 相似文献