酯

Keywords ketene;isopropenyl acetate;esterification;strong acidic cation-exchange resin;fine chemical intermediates

乙烯酮；乙酸异丙烯酯；酯化反应；强酸性离子交换树脂；精细化工中间体

The comparisons of biochemistry between OP and OR rats The differences between OP and OR rats included not only body weight, but lipids metabolism and insulin sensitivity as well, characterized with insulin resistance, increasing in serum free fatty acids and ketone body, and hepatic TC and TG in OP rats. However, no significant differences were observed in serum TG, TC, LDL, HDL and fasting glucose between OP and OR rats.⑶Comparisons of metabolites in serum, urine and liver tissue between OP and OR rats①There were significant differences in amino acids concentration between OP and OR rats,especially in liver tissue, such as high concentrations in ketogenic and glucogenic amino acids in OP rats, suggesting differences in amino acids metabolism;② The different metabolites between OP and OR rats included increasing of various saturated fatty acids and decreasing of polyunsaturated fatty acids in OP rats;③The urinary metabolites analysis indicated that different structure or metabolism of gut microflora might exist between the two phenotypes, which probably influenced the regulation of body weight gain;④The end-products of catecholamines in urine and intermediates of krebs cycle in serum in OP rats were all up-regulated, suggesting that the activity of sympatheic nervous system and energy metabolism was higher in OP rats than OR rats.

胰岛素耐受实验和胰岛素敏感指数表明OP动物的胰岛素敏感性较OR动物下降，而OP大鼠血清中游离脂肪酸、酮体、肝脏总胆固醇和甘油三酯水平显著升高；但是，OP与OR大鼠血清中总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白和空腹血糖等的水平并无显著性差异；⑶肥胖易感与肥胖抵抗大鼠血清、尿液和肝脏组织提取物中代谢物的比较研究表明：①OP与OR大鼠的血清、尿液和肝组织提取物中多种氨基酸的含量存在显著差异，并以肝组织中的差异氨基酸数量为最多，包括各种生酮和生糖氨基酸水平在OP组的升高，说明氨基酸代谢的差异是两种体重表型大鼠之间存在的重要差异特征之一；②OP与OR动物肝脏和血清差异代谢物中包含多种饱和长链脂肪酸的升高如十四烷酸、十六烷酸、硬脂酸等和多不饱和脂肪酸的下降如亚油酸和花生四烯酸，说明两种体重表型动物的肝脏脂肪酸代谢存在明显差异；③长期高脂饮食喂养后，动物的尿液代谢物分析表明OP与OR动物体内的肠道菌群结构存在差异，这些菌群上的差别可能在动物体重增长的调节上产生影响；④与OR动物相比，OP动物尿液代谢物中儿茶酚胺类递质的代谢终产物如高香草酸、扁桃酸和4-羟基苯乙酸明显升高。

The reactive time and reactive temperature are two important parameters for yield of lactide.

反应时间和反应温度是制备丙交酯的两个重要的工艺参数，直接影响丙交酯的产率。

When lactide was purified byethyl acetate for 4 times, it was pure enough to polymerize to be PLA.

以乙酸乙酯作为重结晶溶剂，当重结晶次数达到四次后，其纯度已达到丙交酯聚合的基本要求。

Firstly, through analysis for the synthetic mechanism of lactide and according to improve the condition of synthetic process the factors related were studied in detail.

首先，从改善合成丙交酯反应的条件入手，通过对丙交酯合成反应的机理分析，对反应过程中催化剂用量、种类、脱水温度、时间、压力、解聚温度、时间、压力等做了详细的研究，得出最佳的合成条件和工艺过程。

An indirect spectrophotometric method was used to determine the content of lactide. The factors on the determination, such as the type of solvent, acid and alkali dosage, the time of aminolysis reaction and so on, were discussed.

采用间接光度法测定粗丙交酯中丙交酯的含量，讨论了溶剂类型、胺解反应时间、酸碱用量等因素对测定结果的影响。

The lactide was characterized by IR, 1H-NMR, MS, elemental analysis and Ultraviolet spectrophotometry.

考察了蒸馏工艺、催化剂种类对乳酸脱水效率的影响；用IR、1HNMR、MS、元素分析、紫外光谱分析对丙交酯进行了表征；并考察了丙交酯在不同溶剂中的溶解性。

OBJECTIVE:To explore the mechanism of epilepsy evoked by coriaria lactone,we studied the effects of CL on glutamate release and uptake.

目的：研究致痫剂马桑内酯对谷氨酸摄取和释放功能的影响，以探讨马桑内酯致痫的可能机制。

We will synthesize NO2A, PhNO2A and its dimer structure, and study the stability constants for lanthanides complexes and kinetics in hydrolyzing BNPP. And we also want to understand their differences in catalytic mechanism.

由前人的研究可得知，改变配位子的特性，或许可提高金属错合物对於磷酸酯键的水解效力，因此我们将比较NO2A 及 PhNO2A 对於镧系金属稳定常数，及其镧系金属错合物水解磷酸酯键的影响。

A preferred form of the invention is a process comprising adding to a quantity of sodium which is covered with a hydrocarbon solvent boiling above 100°C., at least a chemically equivalent proportion of methyl, ethyl or a propyl alcohol, subsequently adding an approximately equivalent proportion of a dialkyl carbonate and of an alkyl phenylacetate, the alkyl groups in these two last-mentioned compounds being preferably the same as the alkyl radical of the above-mentioned lower aliphatic alcohol, heating the mixture to induce reaction and continually distilling out the alcohol formed from the reaction zone.

本发明的理想形式包括下面的工艺过程：把至少处于化学平衡的甲醇，乙醇或丙醇添加到覆盖着沸点超过一百摄氏度的碳氢化合物溶剂中，接着加入大约相同当量的二烷基碳酸酯和烷基乙酸苯酯，在刚才提到的化合物中，其烷基集团最好是和刚才提到的低级别脂肪族醇相同，然后加热反应混合物从而引导反应的进行，在反应区域通过连续蒸馏移除形成的醇类。

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。