甲烷

Though the result was not so good, a general understanding of the problems lying in the manufacture process of the device was gotten.We found the symmetry was destroyed or decreased in the crystal structure of symmetrical star-shaped molecules, such as tetra(4-cyanophenoxymethyl-methane, tetra(N-pyrrolemethyl)methane, and a center of charility was self-formed.

本文发现，原本高度对称的星状分子，在晶体结构中，分子对称性破坏或降低，表现为手性分子；以四(4-氰基苯氧基甲基)甲烷为例，从分子间氢键作用的角度，解释了该现象形成的原因。

We found the symmetry was destroyed or decreased in the crystal structure of symmetrical star-shaped molecules, such as tetra (4-cyanophenoxy methyl -methane, tetra (N-pyrrolemethyl) methane, and a center of charility was self-formed. The phenomena was discussed by analyzing the intermolecular hydrogen-bonding interactions of tetra (4-cyanophenoxy methyl -methane.

本文发现，原本高度对称的星状分子，在晶体结构中，分子对称性破坏或降低，表现为手性分子；以四（4-氰基苯氧基甲基）甲烷为例，从分子间氢键作用的角度，解释了该现象形成的原因。

The single mechanical seals of five PHP pumps, nine PLA pumps, two THD pumps and nine ZA pumps in the acetic acid plant were changed into dual mechanical seals based on not changing main parts such as casing, impeller, shaft, bearings house etc. to solve the leakage problems of flammable, explosive, poisonous, harmful substances, such as acetic acid, methyl iodide, hydroiodic acid, and propionic acid etc.

通过对醋酸装置中所选用的5台PHP型、9台PLA型、2台THD型及9台ZA型单级卧式脚支撑化工离心泵，在不改变泵壳、叶轮、轴、轴承箱等主要部件的基础上，将原来的单端面机械密封改造为双端面机械密封或串联式机械密封，以此来防止所输送的易燃、易爆、有毒、有害高危介质（如醋酸、碘甲烷、碘化氢、丙酸等）外漏。

Deep beneath the seafloor, methane is in a slushy, crystalline form.

在海床下面，甲烷是以泥泞状的晶体形态而存在的。

Character: Yellowish or yellow crystalline powder,smell-less; Assay: 98.0%—102.0%; Specific Optical Rotation:+63.0°to +69.0°; Ph:3.0 to 5.0;Clarity of Solution complies with the standard. Related Substance:(Single impurities≤0.5%; total impurities≤1.5%);Methanol:≤0.3%;Dichlormethane≤0.06%Acetone≤0.5%;walter:7.0%—9.5%; Residue on Ignintion:≤0.1%; Heavy Metals:≤0.0002% Identification:Most absorb at the wavelength 220nm,256nm,370nm; The infrared spectrogram according to the comparison; positive reflection

特征及特性：淡黄色或黄色结晶性粉末，无臭；含量98.0%—102.0%；鉴别：1）在220nm、256nm、370nm的波长处有最大吸收；2）供试品溶液在主峰的保留时间与对照品溶液主峰的保留时间一致；3）供试品红外光吸收图谱与对照品的图谱一致；4）呈正反映；比旋度：+63.0°至+69.0°；酸度：3.0—5.0；溶液颜色符合规定；有关物质：（单个杂质≤0.5%；总杂质≤1.5%）甲醇：≤0.3%；二氯甲烷：≤0.06%；丙酮：≤0.5%；水分：7.0%—9.5%；炽灼残渣：≤0.1%；重金属：≤0.0002

After the solution was kept in the dark for five minutes,chloroform was added into it to adsorb selenium formed by previous reaction,then iodine separated out was determined by sodium hyposulfite titration using starch as the indicator,at last the content of selenium dioxide in the sample was foun.

在溶有二氧化硒的0.4～0.5mol/L盐酸介质中，加入过量的碘化钾，于暗处放置5min后，加入三氧甲烷吸附反应生成的硒，以淀粉为指示剂，用硫代硫酸钠标准溶液滴定析出的碘，测得二氧化硒的含量。

Objective: We detected the content of methylene chloride and diethylene oxide in Ceftizoxime Sodium using head-space GC method.

目的：建立一种气相色谱法测定原料药头孢唑肟钠中二氯甲烷和四氢呋喃有机溶剂残留量的方法。

Methane ; Oxidative coupling ; Sodium tungstate ; Manganese oxide ; Supported catalyst ; Redox mechanism

甲烷；氧化偶联；钨酸钠；氧化锰；负载型催化剂；氧化还原机理

We find that solubility of gases in crude oil increase with the increase of pressure.

天然气、甲烷和CO〓的溶解度随温度的升高而减小，N〓的溶解度随温度的升高而增加。

We find that solubility of the gases in crude oil increase with the increasing of pressure.

各气体在原油中的溶解度随着压力的增加而增大，但天然气、甲烷和N2 增加的幅度越来越小，而CO2 增加的幅度越来越大。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。