碱金属元素

It is demonstrated that the chiral quaternary ammonium salts catalysts exhibit promising catalytic properties for the substrate. Part III: The synthesis and the characterizing of the macroporous aminomethyl resin-supported cinchona alkaloid complexes and the study on its catalytic properties The part consists of two subsections. the macroporous aminomethyl resin -supported cinchona alkaloid complexes were synthesized by the stuff (cinchonine, quinine and macroporous aminomethyl resin). Their structures were characterized by means of elemental analysis, XPS, TG/DTA; the chiral polymer-supported complexes were first used as catalysts for the reduction of ketones. Their catalytic properties for the reduction processes were investigated. The comparison of the products e.e., the conversion of the substrate among different reduction processes was employed with determined by HPLC. The effects of the time, the temperature, the ratio of catalyst to substrate, reaction solvent as well as the recycle times were also discussed.

第三章聚-4-氨甲基苯乙烯负载金鸡纳碱金属络合物的合成与表征及其不对称催化性能研究本章分为两节，以辛可宁和奎宁及聚-4-氨甲基苯乙烯为原料，合成了4种聚-4-氨甲基苯乙烯负载金鸡纳碱络合物催化剂，并对它们的结构用元素分析、X-射线光电子能谱、TG/DTA等几种测试手段进行了表征；首次将所合成的手性高分子负载的金属络合物用于催化芳香酮不对称还原反应，详细研究了所得的手性高分子负载的金属络合物对不同底物的催化性能，用HPLC等分析手段定量检测了还原过程的底物转化率及其产物对映异构体选择性，并考察了反应时间、反应温度、催化剂和底物投料比、反应溶剂和循环次数对催化性能的影响。

The immediate product of the radioactive decay of an element.

一种碱金属属的放射性元素，是锕瓦解的产物。

The elements such as copper, sliver and gold, the so-called coinage metals, are sometimes treated with the alkalis

诸如元素铜、银和金等所谓的货币金属，有时被与碱金属一同看待。

According to the change of the kinds of elements content in slag, F in slag volatilizes in the form of KF and NaF, KF volatilizes much more easily than NaF, KF plays a leading role in the F volatilization, theoretical analysis shows that the saturation vapour pressure of KF in the test slag is 31. 4 times of NaF; when F content is far more than K, KF volatilization is first order grade reaction, it is dominated by K content, the apparent activate energy is 275. 30KJ/mol.

4依据对含氟熔渣中高温条件下（1450℃、1505℃）的各种元素含量的变化情况，发现氟在熔渣中是以碱金属氟化物挥发，并且，KF比NaF具有更好的挥发性，在氟的挥发中占主导地位，理论研究也证明，在1505℃试验组成的熔渣中，KF的饱和蒸气压是NaF的31.4倍；在含氟量远大于钾含量的情况下，KF挥发为一级反应，受钾浓度控制，其表观活化能为275.30KJ／mol。

PTFE referred to F4, because of its excellent dielectric properties and corrosion-resistant chemical (high temperature of the molten fluoride elements and the state of alkali metal), non-absorbent, non-stick, not conductive, low coefficient of friction and not Ageing properties, and is widely used in chemical, petroleum, textile pharmaceutical, metallurgy, machinery, electronics, electrical appliances, electricity, food and aviation, military and scientific research in all walks of life, I plant the development of metal bellows, compensation , PTFE bellows F4 tetrafluoroethane compensator, F4 metal composite compensation, anti-corrosion steel liner tetrafluoroethane pipe, steel-lined tetrafluoroethane three links, elbow, Stone, the reaction tower, tower chloride, lining tetrafluoroethane valve Doors, tetrafluoroethane pads and steel-lined polypropylene pipes and accessories, and earnestly solve the user in the production process by the various anti-corrosion problems.

聚四氟乙烯简称F4，由于其优异的介电性能与耐化学腐蚀性(高温下的氟元素和熔融状态下的碱金属外)，不吸水、不粘、不导电、摩擦系数低及不老化等性能，而被广泛应用于化工、石油、轻纺制药、冶金、机械、电子、电器、电力、食品及航空、军用与科研等各行各业中，我厂开发的金属波纹管、补偿器，四氟波纹管F4四氟补偿器、F4金属复合补偿器，钢衬四氟防腐管件，钢衬四氟三通、弯头、四通、反应塔、氯化塔、衬四氟阀门，四氟垫片以及钢衬聚丙稀管道及配件，切实解决了用户在生产过程中所遇到的各种防腐问题。

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。