转环

In a DMF solution of CuCl〓-ethanolamine-acetic acid (1: 2: 2), 27 formed a highly oxidized heterocyclic compound 2-hydroxymethyl-naphtho [1, 2-a] oxazole (30) by the carbon-nitrogen coupling and carbon-oxygen coupling with the ligand of ethanolamine, which brings a chance to develop a novel approach to this heterocyclic compound via one-pot reaction of phenols under mild condition.

在氯化铜—乙醇胺—乙酸（1：2：2）的DMF溶液中，27与配体乙醇胺发生碳氮偶合与碳氧偶合，生成深度氧化的杂环化合物：2-羟甲基-萘并[1，2-a]〓唑（30）。这可望为酚类一锅化直接转化为30及其类似物提供一种简便的新合成路线。

In order to check the corresponding compound at 31P NMR –45.4 ppm, stable pentacoordinate spirobicyclic 2-phenoxy-1,3-phenylene-dioxo-1,3,2-iminoacetoxyphosphoranes were synthesized through a new and efficient method whereby phosphorus pentachloride was displaced stepwise by catechol, N,O-bisamino acid and phenol, or catechol, phenol and N,O-bisamino acid, their 31P NMR chemical shifts are at about 31P NMR –45.0 ppm, the results showed that the compound 4 at 31P NMR –45.4 ppm was pentacoordinate phosphorane containing amino acid residue.

采用磷谱跟踪来研究上述成肽反应机理。例如在氮气保护下，0.1mmol O，O-亚苯基磷酰氯（1）和0.15mmol N，O-二苯丙氨酸（2）苯溶液加入0.6ml核磁管中，混合均匀，反应过程用磷谱检测。反应1分钟后，起始原料1(δp=19ppm)很快转变成N-磷酰苯丙氨酸的三甲基硅基酯（3）(δp=19.8ppm)，在8分钟内，3完全转变成苯丙氨酸磷烷4(δp =-45.4ppm)，同时出现环磷三酯（6）(δp=3.5ppm)。随着反应的进行，对应于化合物4的峰逐渐变小，而6逐渐变大。

On the view of the result of experiment, the motor started stably and quickly with small toque pulsant and had wide scope of speed adjustment. It can content all of the request of the compressor of refrigeratory.

本控制系统是针对冰箱压缩机电机研制的，从试验的测试结果来看，电机起动稳定快速、转矩脉动小，具有较宽的闭环调速范围，完全满足冰箱压缩机电机各项性能指标要求。

The development of the research on slubby yarn is introduced and four types of spinning principles of weaving slubby yarn are compared.

介绍了竹节纱研究的发展趋势，比较了四种纺纱原理，并重点论述了环锭纺竹节纱和转杯纺竹节纱的方法，和对纺制竹节纱的工艺和质量控制作了探讨

The article focuses on the aberrant expression and significances of proto-oncogenes, tumor suppressor genes and genes associated with the proliferation process of gastric cells such as telomerase, transcription factor and cyclooxygenase, etc. These genes, alone or synergically, participate in gastric cancer cell proliferation, resulting in an uncontrolled growth characterized by over-proliferation of decreased apoptosis of gastric cancer cells.

本文着重阐述了与胃癌细胞增殖过程密切相关的端粒酶、核转录因子、环氧化酶等基因以及参与细胞周期调控的原癌基因、抑癌基因的异常表达及临床意义，这些基因或单独作用，或相互协同，参与胃癌细胞的增殖，使肿瘤细胞生长以增殖过多、凋亡过少的失控性生长为特征。

Tang X, Gao J, Wang Y, et al. Effective protection of Terminalia catappa L.leaves from damage-induced by carbon tetrachloride in liver mitochondria［J］.

本实验观察到环磷酰胺低、中剂量组的小鼠肝脏线粒体中VDAC的转录水平较对照组有所下降，而高剂量组则略高于正常对照组。

At first,the prin ciple of BLDCM is analyzed and the model is built;then a test is performed on a tining system of close loops of speed and current;torque ripple components are r educed by controlling switching andles of the PWM.

文中首先建立永磁无刷直流电机的数学模型，以此进行转速和电流双闭环调速系统控制；并通过调节 PWM发生器的开关频率来减少转矩脉动。

Biogenic amines are basic nitrogenous compounds formed mainly by decarboxylation of amino acids or by amination and transamination of aldehydes and ketones.

生物胺是一类含氮的脂肪族、芳香族或杂环类低分子化合物，主要是通过氨基酸的脱羧或醛和酮的胺化和转氨基作用形成的。

Rotating machining tools, round rods, circular knives circular saws, countersinking tools, turning tips, guide gibs, knive blades.

可转位加工工具、圆棒、环刀、圆盘形锯、钻孔工具、车刀、导向槽、刀片。

RKF RKS Rotating machining tools, round rods, circular knives circular saws, countersinking tools, turning tips, guide gibs, knive blades.

可转位加工工具、圆棒、环刀、圆盘形锯、钻孔工具、车刀、导向槽、刀片。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。