环

The features to evaluate the tooth contact quality such as the location of the contact point on the tooth surface, clearance between the meshing tooth surfaces, curve of the transmission error and the path of the contact point are investigated. The accurate geometric representation with non-uniform rational B spline of the worm and the wheel tooth surface is presented then the corresponding program is developed.

根据平面包络环面蜗杆传动的创成方法，建立了包含加工误差的蜗杆和蜗轮的齿面方程，分析了平面包络环面蜗杆传动和平面二次包络环面蜗杆传动的刚性啮合特性如误差对接触点的位置、齿面间隙、传动误差曲线和接触点在齿面上的轨迹的影响。

Abrasive disk for accurately grinding TI worm,as well as grinding method similar to that for globoid worm or planer enveloping hourglass worm,is used to machine hourglass worm,making the TI worm match with the worm wheel which has the same tooth surface shape as that of abrasive disk,and thus forming a new-style worm gearing .

采用精确磨削TI蜗杆的砂轮，用类似直廓环面蜗杆或平面包络环面蜗杆的磨削方法加工环面蜗杆，使该蜗杆和齿面形状与砂轮曲面相同的蜗轮相配合，形成一种新型蜗杆传动，给出了这种传动蜗杆副齿面的数学模型，并通过计算机仿真得出了这种传动蜗轮齿面上接触线的形状及分布特征，初步分析了其啮合特点。

0 G of cyclopentyl bromide and 19.4 g of magnesium are reacted in ether or THF to give a cyclopentyl Grignard reagent.

一百十九点零克的环戊基溴或溴环戊烷和十九点四克的镁在乙醚或四氢呋喃中产生反应，形成一个环戊格氏试剂。

In some special situation, Anti-static foot grounder will take place of anti-static wrist strap, and it is more economical than anti-static shoes.

防静电脚步环在某些需要机动性的场合里，防静电鞋或脚环成为同功能手腕带的替代品，而接地脚环又比防静电鞋更为经济。

Sample of companies in the third quarter net profit growth ring than the number of companies is only 497, 158, Central than the growth rate more than 50%, more than 101 ring for more than 100% growth rate.

样本公司在第三季度的净利润比增长的公司数目只有497环，158环比增长速度超过50％，超过101环超过100％的增长率。

In the present paper, we determined the mitochondrial DNA sequence 539bp of the high variable I D-loop regions(mtDNA HVS-I) for 243 domestic fowls 19 were Wugu (or black-bone chicken and 8 non-wugu breeds/races and 38 red jungle fowls (Gallus. Gallus. spadiceus and Gallus. Gallus. jabouillei). We also sequenced 289bp mitochondrial DNA of Cyt-b for 5 red jungle fowls; D-loop region (mtDNA HVS-I)for 19 individuals Guinea fowl and 18 individuals mule chickens (Guinea fowl $ x Wugu chickens^ ) respectively; mtDNA HVS- II of D-loop region for 34 individuals of domestic fowls and red jungle fowls in 690bp and the MC1R code gene in 945 bp.

本文共测定了19个乌骨鸡品种及8个非乌骨鸡品种的243个家鸡和38个原鸡个体(属于Gallus.gallus.spadiceus和Gallus.gallus.jabouillee亚种)的线粒体D-环高变区(mtDNA HVS-Ⅰ)539bp的部分序列，另外还测定了5个红原鸡个体线粒体细胞色素b的289 bp序列、19个珍珠鸡个体、18个骡鸡个体的线粒体D环高变区序列、30个家鸡个体线粒体D环非高变区的690bp序列以及34个家鸡及原鸡个体的MC1R基因编码区的945bp。

The reaction of an azetidine with chloroformate can give either the dealkylated heterocycle or the ring-opened product.

与氯的反应氮杂环丁能给要么dealkylated杂环或环打开产品。

In this report, a series of nitrogen heterocycle porphyrin compounds were obtained by introducing a pyrazole heterocyclic ring with high fluorescent quantum yield to the parent porphyrin.

本文通过将具有较高荧光量子产率的吡唑杂环化合物连到卟啉环的中位而得到一类新型的含氮杂环卟啉。

For distinctly understanding the mutual influence between the structural units, a series of compounds from five and six-membered C-N heterocycle substituting the tetrazine ring are designed. These several types of compounds are studied by means of the quantum chemistry calcualtions and discussed the influence of the structural units upon the main performance (heat of formation, density, velocity and pressure of detonation) and found out the best combination of performance.

为了更清楚的了解结构单元之间的相互影响，设计了六元氮杂环和五元氮杂环取代1，2，4，5-四嗪得到了一系列化合物，采用量子化学计算方法对它们进行了详细的理论研究，讨论了各种氮杂环的改变对四嗪类化合物性能(包括生成热、密度以及爆速和爆压等)的影响，并找出爆轰性能较好的结构单元组合。

With the single-crystal X-ray studies, the nanoscale rigid cavity of the aromatic macrocycle was approved, and nature of the heteromorphism of aromatic macrocyclic oligomer was also explained with the study of two kinds of single crystal with different steric structures.

并利用单晶X光衍射技术研究了三种不同结构的环状齐聚物的单晶结构，第一次通过大环分子与其对应线性齐聚物键长、键角和二面角的变化解释了聚芳醚酮类刚性大环分子环张力产生的原因。

I can not make it blossom and suits me

我不能让树为我开花

When temperatures are above approximately 80 °C discolouration of the raceways or rolling elements is a frequent feature.

当温度高于 80 °C 左右时，滚道或滚动元件褪色是很常见的特征。