环

One was HF/pyridine diazotization reaction at the 4-position of fluorene ring, and the other was Grignard reaction on the 9-position with Grignard reagent of pentafluorochlorobenzene.

使用HF/吡啶法在芴环的4位引入了氟原子，使用五氟氯苯格氏试剂在芴环的9位引入了全氟苯，合成了五个氟取代三联(9，9-二苯基)芴化合物。

The analysis method for determination of trace ethylene dichloride was established in PrimaδB process mass spectrometer.

乙烯氧化制环氧乙烷生产过程是在银催化剂作用下，乙烯催化氧化生成环氧乙烷反应。

Insufficient adjuster torque will not support the ring gear correctly and can cause excessive differential case free-play and ring gear noise.

调整器扭力不足将不能正确地支撑环齿轮并会导致过度的差速箱游隙和环齿轮噪音。

The result shows that both of the two C-C double bond are exist as a trans configuration. The dihedral angle between benzene ring was 24.6°and 37.5°respectively.

发现均二苯乙烯荧光团的两个双键都是以反式结构存在，并且分子中的苯环并非完全共平面，相邻苯环之间的夹角分别为24.6°和37.5°。

The influences of the amount of 1,2-diaminoethane, temperature, molar ratio of epichlorohydrin and dimethylamine, and time on the viscosity and cationic degree of polyamine flocculants were investigated.

以环氧氯丙烷和二甲胺为原料，乙二胺为交联剂，制备有机阳离子聚合物，研究乙二胺加入量、反应温度、环氧氯丙烷和二甲胺的摩尔比、聚合时间等对聚合物粘度和阳离子度的影响。

The Fresnel lens, also known as the dioptric lens, consists of a central glass disk and concentric glass rings or a central glass band surrounded by parallel glass rings.

一个在中心的玻璃圆片和与之同圆心的层层玻璃圆环，或者中间是一个玻璃带，两边是与之平行的玻璃带状环。

The method of liquid phase synthesis of dioxane from the cyclodehydration of diethylene glycol catalyzed by ASP-type solid acidic catalysts was studied.

研究了ASP型固体酸催化剂一缩乙二醇环化脱水合成1，4-二氧六环的液相反应。

The circular dichroism spectra of soluble CSL in the presence of dioxane showed that dioxane made the αhelicity of the CSL increase.

CSL在二氧六环介质中的CD谱的变化表明：二氧六环使CSL分子中的α-螺旋含量有所增加。

Dioxane is a byproduct of a petrochemical process called ethyoxylation, which involves using ethylene oxide to process other chemicals in order to make them less harsh.

1，4二氧六环的副产品是一个石化过程被称为ethyoxylation ，其中包括利用环氧乙烷，其他化学品，以使它们显得温和。

In the study of by-product dioxane in polymerization reaction of EO,it is found that the effect of solvent is very small.And so do the catalyst BF_3-H_2O complex and catalyst H~+.

计算结果也解释了BF_3-H_2O催化环氧乙烷聚合产物分子量达到某一极限值后不再增加，消耗的单体都生成了二氧六环的原因。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。