查询词典 methyl

The excited-state intramolecular proton transfer tautomerism reaction of 6-methyl-4-hydroxy pyri-midine monomers and dimmers was investigated by the ab initio method with the self-consistent reaction field with Tomas's polarized continuum mode and CIS theories at HF level on the basis of 6-311+G* and 6-31G basis set. By studying the potential energy surface, it was found that the monomer's ground-state proton transfer process together with the excited-state proton transfer process is a molecular system of four energy level, but dimmers were not, which can be used to explain the fact that UV-visible absorption and fluorescence spectra of monomer and dimers all corresponded to quinoid.

采用 ab initio HF理论的组态相关CIS方法和连续溶剂模型PCM，分别在6-311+G*和6-31G水平上研究了6-甲基-4-羟基嘧啶单体及二聚体激发态质子转移的异构化反应；对其反应势能面的研究发现，单体基态和激发态的异构化反应一起可以形成四能级的分子电子体系，而二聚体的却不能，由此解释了单体和二聚体的紫外吸收光谱和荧光发射光谱均对应于酮式构型的原因。

The mechanism of synthesizing methyl quinoxaline di-N-oxide has been put forward and the side reaction causes suggested.

讨论了合成条件，并且用红外光谱、元素分析、质谱和HNMR对40种目标化合物的结构进行了分析和表征。

Methyl quinoxaline roast nut,roast corn,coffee

5-甲基喹喔啉烘烤坚果，烘烤玉米，咖啡

We examined the association between intakes of the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5,-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine,2-amino-3,4,8-trimethylimidazo[4,5,-f] quinoxaline, and meat-deried mutagenicity and risk of distal colon adenoma using a cooking method questionnaire administered in 1996 in the Health Professionals Follow-up Study cohort.

我们卫生保健跟踪调查组采取烹调方法调查表的形式在1996年调查了摄入杂环胺2－氨基－3，8丙烷[4，5，-f] 喹噁啉，2－氨基－1甲基1－6－苯基亚氨基[4，5-b] 吡啶，2－氨基3，4，8－trimethylimidazo[4，5，-f] 喹噁啉和肉类衍生致突变物与患末端结肠腺瘤危险性的关系。

We examined the association between intakes of the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5,-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine,2-amino-3,4,8-trimethylimidazo[4,5,-f] quinoxaline, and meat-derived mutagenicity and risk of distal colon adenoma using a cooking method questionnaire administered in 1996 in the Health Professionals Follow-up Study cohort.

我们卫生保健跟踪调查组采取烹调方法调查表的形式在1996年调查了摄入杂环胺2－氨基－3，8丙烷[4，5，-f] 喹噁啉，2－氨基－1甲基1－6－苯基亚氨基[4，5-b] 吡啶，2－氨基3，4，8－trimethylimidazo[4，5，-f] 喹噁啉和肉类衍生致突变物与患末端结肠腺瘤危险性的关系。

Benzyloxy benzoyldimethylsulfoxide was prepared by the reaction of ethyl 4-benzyloxybenzoate and dimethyl sulfoxide in the presence of sodium hydride, followed by Pummerer reaction with concentrated hydrochloric acid to afford eo-hydroxy-co-thio-methyl-(4/-benzyloxy) acetophenone, which reacted with urea, thiosemicarbazide, semicarbazide hydrochloride and o-phenylenediamine to give imidazolidine-2,4-dione, l,2,4-triazine-3- one and quinoxaline derivatives, respectively.

本文用4-苄氧基苯甲酸乙酯和二甲亚砜为原料，在氢化钠存在下反应，合成了(4′-苄氧基)-苯甲酰基-二甲亚砜。研究了该亚砜在浓盐酸的存在下发生的Pummerer重排反应，用重排产物ω-羟基-ω-甲硫基-(4′-苄氧基)-苯乙酮分别与尿素、氨基脲、氨基硫脲和邻苯二胺反应合成了2，4-咪唑啉-二酮、1，2，4-三嗪-3-酮、喹喔啉等含氮杂环化合物。

Methyl quinoxaline toasted,coffee

2-甲基喹喔啉烤面包，咖啡

Objective To analyze the components of organic acids in the Radix Ranunculi Ternati from different methods. Methods With using 10%H2SO4-CH3OH as methyl esterification solvent, the analysis for organic acids were carried by using GC-MS . Results 46 components were determined.

目的 分析不同提取法提取的猫爪草有机酸部位的成分方法采用离子交换法提取分离水提液和醇提液中的有机酸，以10%硫酸甲醇溶液甲酯化试剂进行甲酯化，用气相色谱-质谱联用技术分析。

MSM is a natural sulfur-containing compound produced by kelp in the ocean. Sulfur is stored in almost every cell in the body. The highest concentrations are found in joints, hair, skin, and nails. MSM is claimed to be an antioxidant, cell rejuvenator, and joint healer.

MSM 是methyl-sulfonyl-methane的简称，它是一种自然有机的硫磺，硫磺是身体内第四大主要成份，而且在身体内的每个细胞内都可找到硫磺的成份，在食物中也可以找到硫磺的成份，但是因为清洗烹煮而会使硫磺成份流失，身体会藉用MSM来制造健康的新细胞，和增进身体的健康，同时MSM亦被视为是一种天然的止痛和抗肿成份。

By employing such a method, 5 series of elastomers, including natural rubbers, elastomeric polyester fibers and ethylene-octene, ethylene-methyl acrylate as well as SIS triblock copolymers, were investigated with the purpose of studying elongation induced phase structure and mobility changes of the samples. For NR samples, it was demonstrated that there exists a small amount of crystals at RT even for unelongated samples. For both NR and the soft segment of PEE, with the increase of elongation ratio, the elongation-induced crystallinity increases almost linearly in a certain region of R, in accord with the increase of the lamellar thickness of the crystals; The behavior of ethylene copolymers, in terms of elongation induced morphorpholgy changes, are quite different from NR and PEE. The crystals are found to be gradually destroyed with the increase of R, with accord with the decrease of the lamellar thickness; The motional behavior of the soft segment of SIS, changes from "liquid" to "solid", in terms of 13C NMR spin-lattice relaxation.For many of the aformented samples, the dependence of 13C spin-lattice relaxtion time T1 on R are different for different groups, indicating that the changes of mobility at MHz frequency region with elongation are different for different groups.

通过对天然橡胶、聚醚酯嵌段共聚物、乙烯-辛烯共聚物、乙烯-丙烯酸甲酯共聚物、SIS等高分子弹性体样品聚集态结构和分子运动的研究，获得了一些新的实验结果，如：给出了确切的实验证据，证明了室温下未拉伸的天然橡胶样品中存在着微量的结晶；发现随着拉伸比增加，天然橡胶及聚醚酯样品的软段部分会出现拉伸诱导的结晶，且结晶度在一定范围内呈现近似线性的增加，所形成晶片的厚度也随之逐渐增加；而乙烯共聚物随着拉伸比的增加，原有的结晶会被逐渐破坏，晶片厚度逐渐变薄，结晶中的缺陷逐渐增加；随着拉伸比的增加，SIS中PI软段部分的核磁共振弛豫行为会出现从液态到固态的转变等；在对上述多个体系的研究中，还发现不同基团的自旋-晶格弛豫时间随着拉伸比呈现不同的变化趋势，表明不同基团的高频运动随拉伸比增加有不同的变化规律。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。