硫酸

Crystallized sulfuric salt of SAM was obtained by centrifuging the precipitant at 3000 rpm after adding six times the volume of absolute methanol to the decolorant liquid with a final step of freezing evaporation.

确定了分离纯化SAM的最优条件是：在pH值5.0时，含SAM浓度为3.0 g/L的上柱液，以6 L/h的流速，过装填D152树脂的离子交换柱(φ50 mm×1500 mm)后以去离子水和醋酸洗脱除杂，再用9 L到15 L浓度为50 mmol/L的硫酸以6 L/h的流速洗脱，可以分离得到纯度较高的SAM粗品。

The industry magnesia mainly uses in making the ceramics, the enamel, the fire-proof material and so on; In the polishing compound, the adhesive, in the paint manufacture takes the stopping; In the artificial fiber, the rubber (chloroprene rubber, fluorine rubber) make the promoter and the catalyst; Makes the antacid on the medicine in the laxative, uses in treating the hyperacidity, the stomach and duodenum ulcer; May take the hard sugar purification is the decolorant in the food processing, the ice cream pH value conditioner and so on; In the construction profession, the magnesia may the manufacturing contain the magnesium special cement and the heat preservation board and so on; The biggest use is serves as the fertilizer and domestic animal's feed in the agriculture, causes the plant and in the animal metabolism process principal element, when serves as cow's feed, may prevent because to lack nervous system function being out of balance which the magnesium causes, namely the so-called forage grass convulsion gets sick; Uses in the chemical industry making the metal magnesium and the magnesium chemical, like magnesium sulfate, magnesium chloride as well as other chemicals; Moreover also uses in the water treatment, the detergent which the flue was mad uses in the glass, the dye, the electric cable, the silcon steel industry, the uranium processing, the electronics industry, the insulation material industry, as well as uses in professions and so on petroleum chemical additive, casting, phenolic plastic.

工业氧化镁主要用于制造陶瓷、搪瓷、耐火材料等；在抛光剂、黏合剂、油漆的制造中作为填充料；在人造纤维、橡胶中作促进剂和催化剂；在医药上作抗酸剂于轻泻剂，用于治疗胃酸过多、胃和十二指肠溃疡病；在食品加工上可作为砂糖精制是的脱色剂，冰淇淋的pH值调节剂等；在建筑行业中，氧化镁可生产制造含镁特种水泥和保温板等；在农业上最大用途是用作肥料和牲畜的饲料，使植物和动物代谢过程中的主要元素，用作奶牛的饲料时，可防止因缺镁而引起的神经系统机能失调，即所谓牧草性痉挛病；在化学工业中用于制造金属镁和镁化学品，如硫酸镁、氯化镁以及其他化学品；另外也用于水处理，烟道气的洗涤剂用于玻璃、染料、电缆、硅钢工业、铀加工、电子工业、绝缘材料工业，以及用于石油添加剂、铸造、酚醛塑料等行业。

Of the 4 soil enzymes studied, alkaline phosphatase and dehydrogenase were higher than urase and arylsulfatase in activity.

在所测定的4种土壤酶中，碱性磷酸酶和脱氢酶的活性高於脉酶和芳基硫酸酯酶的活性。

To better understand the principles of enzymatic unhairing, changes of contents of protein, hydro-proline and glucose in depilatory liquors were determined in Lowery method, DMBA method and Sulfuric Acid-Anthrone method, respectively, during bath dehairing procedure of 2709 proteinase and A.

为更好地理解酶脱毛的机理，本文用Lowery法、对二甲胺基苯甲醛法和硫酸－蒽酮法分别测定了2709酶和A.S1398酶有温有浴酶脱毛过程溶液中的总蛋白、羟脯氨酸及糖含量的变化。

The properties of this surfactant were examined by numbers, including surface tension, foaming power, wetting power, emulsification, detergence, dispersion ability, stability in hard water and thermal stability.

对产物双十二烷基乙氧基二硫酸酯钠进行系统的性能研究，包括表面张力、泡沫力、润湿力、乳化力、去污力、分散力、在硬水中的稳定性和热稳定性等。

So for the material resistance to corrosion by sulfuric acid dew point is very important to study the theoretical significance of the actual value, its future development prospects will very broad.

因此对于金属材料抗硫酸露点腐蚀的研究有着非常重要的理论意义各实际应用价值，其未来的发展前景必然十分的广阔。

This paper deals with the preparation and application of the cationic diamide softening agent ,which is synthesized by using cattle oil,Diethylenetriamine and dimethyl sulfate.

以牛油、二乙烯三胺和硫酸二甲酯为主要原料合成了一种新型阳离子双酰胺类纸张柔软剂。

They had suppressed the cathodic process of carbon steel electrode. Their inhibition performance was also related with their molecule stereo conformation and electron configuration. Four of bis-(1, 1'-benzotriazoly)-α,β-diamide compounds linked via-CO 〓CO-chain were synthesized and certified by IR and 〓H-NMR. The minimum energy conformations of these compounds were obtained by MM2 forcefield program. The two benzotriazole moiety in BBT1 was more planar than in other compounds. This was beneficial in increasing the inhibition effects of BBT1. In 0.5M H〓SO〓 solution, BBT1 suppressed anodic corrosion reaction. In 3%NaCl solution, BBT1 suppressed both cathodic and anodic corrosion reactions. 1- [ (1'-imidazolly)-methyl] benzotriazole was synthesized by Mannich reaction.

合成了四个通过-CO〓CO-连接的双（1，1'-苯并三唑）-α，ω-二酰胺化合物，采用MM2分子力学程序优化了它们的分子结构，双（1，1'-苯并三唑）-α，ω-二酰胺化合物的缓蚀作用与其分子内两个苯并三唑单元的空间取向有关系，良好的平面性有利于苯并三唑二聚体的吸附和缓蚀作用，苯并三唑二聚体BBT1分子内两个苯并三唑单元近似平行，所以显示出较好的缓蚀效果。0.5M硫酸中BBT1主要抑制铜的阳极溶解的电化学反应；3％NaCl溶液中，BBT1对铜的阳极溶解和氧的阴极还原过程均有抑制作用，相比较而言对阴极过程的抑制作用更大一些。

The obtained Dichondra Repens forst polysaccharides were determined by spectrophotometry at wavelength 490nm with phenolsulfuric acid as a color reagent.

多糖经苯酚－硫酸显色后在490hm处用紫外－可见分光光度计进行比色测定。

Potassium dichromate was replaced by ceric sulfate as oxidant to determine the COD in this study.

采用硫酸高铈作为氧化剂来测定难降解垃圾渗滤液的COD，测定结果与重铬酸钾法进行比较。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷