酯

The results show that: 27 compounds were identified at 600℃, and most of them were alkenes, alkanes, acids, alcohols and phenolic substances; geraniol was identified, and its relative content was 3.6, which shows that geranyl 8-methoxycoumarin-3-carboxylic acid ester can release a certain amount of geraniol at smoke temperature; geranyl 8-methoxycoumarin-3-carboxylic acid ester can improve and modify the flavor, enhance the notes of sweet aroma and bean aroma, and reduce the biting taste of cigarette smoke.

结果表明，600℃时，8-甲氧基－香豆素－3-甲酸香叶酯的热解产物中共鉴定出27种成分，主要为烯类、烷类、酸类、醇类、酚类；鉴定出香叶醇，且相对峰面积3.6，说明8-甲氧基－香豆素－3-甲酸香叶酯能在卷烟燃吸温度下释放出一定量的香叶醇；8-甲氧基－香豆素－3-甲酸香叶酯具有改善和修饰卷烟香气，增加甜韵和豆香香韵，减轻刺激性的作用。

Secondly, triacylglycerol was obtained via lipase-catalyzed esterification of PUFA-rich fatty acid with glycerol. The TAG contents in the glyceride fraction reached 96 wt% with a degree of esterification of 94% after 6 h.

其次，将富含PUFA之脂肪酸与甘油在酵素催化反应下得到三酸甘油酯；反应6小时后产物甘油酯中TAG含达96 wt%，酯化程达94%。

Cephalotaxine ester of 2-oxo-6-methylheptanoic acid was treated with lithium diisopropylamide and Me O-(1-methoxyisopropyl)glycolate to give a mixture of homoisoharringtonine and its stereoisomers with 56% yield. The four stereoisomers separated by TLC showed identical mass spectra and almost superimposed IR but with different 1H NMR spectra. The configuration of the 2'-C and 3'-C of the four isomers were postulated based upon their 1H NMR spectra as compared with the 1H NMR spectra of isoharringtonine and its stereoisomers.

2-氧代-6-甲基庚酰基三尖杉碱(3)与0-(1-甲氧基异丙基)羟基乙酸甲酯(4)在强碱性试剂二异丙胺锂存在下，起亲核加成反应，反应中间体5在室温用酸性丙酮水解，得到一种新的三尖杉酯类生物碱一一高异三尖杉酯碱(6c)及其立体异构体(6a、6b、6d)的混合物，产率56%、通过制备薄层层析分得这四个立体异构体，它们的1H NMR和异三尖杉酯碱及其立体异构体的1H NMR类似，推定了它们的绝对构型。

Simultaneously, how the gum acacia affects the hydrolysis rate constants of fatty acid esters in 38.6% ethanol solution, and the combination behavior between gum acacia and fatty acid esters have been found. And the way to determine the combination costants between them quantitatively is also found. In addition, the validated quantitative mathematic expression between hydrolysis rate constants of ester and the concentration of gum acacia: k=k'/(1+AM) is verified.

同时研究了38%乙醇溶液中阿拉伯胶与脂肪酸酯之间的缔合行为，并建立了定量确定缔合常数的方法，推导并验证了定量表达酯水解速率常数k与GA浓度关系的数学表达式：k'=k/(1+AM)，得出了GA对脂肪酸酯水解起禁阻作用的结论。

OBJECTIVE: Three sesquiterpene lactones 1-O-acetylbritannilactone, isoalantolactone and britannilactone were isolated from the roots of Inula helenium and the flowers of Inula japonica. The antitumor activities of the three sesquiterpenoids in the cell lines of HeLa, HEC-1, SHIN3, HOC-21 and HAC-2 were measured, and the relationship between structure and activity and the possible mechanisms were explored.

目的： 观察菊科植物中分离出的3种倍半萜化合物异土木香内酯、1-氧-乙酰大花旋覆花内酯和大花旋覆花内酯对体外培养的人子宫颈癌HeLa细胞、人子宫内膜癌HEC-1细胞、人卵巢透明细胞癌SHIN3及HOC-21细胞和人卵巢囊腺癌HAC-2细胞增殖的影响，研究这3种倍半萜化合物的体外抑制肿瘤细胞增殖作用及其结构与活性之间的构效关系，进而探讨3种倍半萜化合物的体外抑制肿瘤细胞增殖的可能机制。

The same compounds can be characteristic compounds of Curculionidae and were 1,2- Benzenedicarboxylic acid, decyl hexyl ester, n-Eicosane and 1,2,4-Benzenetricarboxylic acid, 4-dodecyl dimethyl ester.

两种害虫蜡层和护蜡层共有成分分别是：1，2-苯二甲酸-1，2-（2-甲基-1）-丁醇二酯、正二十烷和1，2，4-苯三甲酸-（4-正十二醇酯）-1，2-甲二酯，它们可能具有象虫属的特征。

On the NiO/SiO〓 catalyst prepared by IM, the main hydrogenation product of MA was SA, the activity and selectivity were almost no relation with the nickel content and nickel species 3. Summarizing the characterization and activity evaluation of the catalysts, we concluded: On nickel based catalyst, when NiO was crystallite, and the Ni〓 that was prepared by reducing, hydrogenation of the MA could lead to SA but not to γ-BL; when NiO was cluster and had a properly interaction with the support, the Ni〓 prepared by reducing, could hydrogenate MA to SA then to γ-BL. When NiO cluster and crystallite were both existed on the catalyst, the hydrogenation products were mixture of SA and γ-BL, and the amounts of SA and γ-BL were related with the ratio of cluster and crystallite.

综合催化剂的表征和活性评价得出：当镍基催化剂上氧化镍以结晶态存在，经氢还原后的零价镍可使顺丁烯二酸酐加氢得到丁二酸酐，丁二酸酐难以进一步加氢为γ-丁内酯；当镍基催化剂上氧化镍以簇团形式存在，与载体之间有适当的相互作用时，经氢还原后的零价镍可使顺丁烯二酸酐加氢得到的丁二酸酐进一步加氢为γ-丁内酯；若催化剂上氧化镍既有结晶态又有簇团形式时，随二者含量比例不同而得到丁二酸酐和γ-丁内酯的混合物。

Meanwhile cyclodextrin can simulate ester hydrolase,which also may have an impact on itself.Up to now,there is no research focused on the stability of cyclodextrin ester.

同时环糊精本身就可以模拟酯解酶，也有可能对自身酯键产生影响，目前还没有专门真对环糊精酯键稳定性的相关研究。

Second, plasticizers industry trends: the main production of plasticizer tends to continuous large-scale production, and special plasticizers tend to many varieties, small batch intermittent production; products, traditional, low-cost, security risk phthalate plasticizers are being new, safe but relatively high prices of citric acid ester plasticizers, trimellitic acid plasticizer replaced this trend performance in foreign markets significantly, and domestic prices because of factors, phthalate plasticizers will be substantial use.

二、增塑剂行业发展趋势：生产方面主增塑剂趋于连续化大生产，而特殊增塑剂趋于多品种、小批量间歇生产；产品方面，传统的、廉价的、安全风险大的邻苯二甲酸酯类增塑剂正在被新型的、安全的但价格相对较高的柠檬酸酯增塑剂、偏苯三酸类增塑剂所取代，这一趋势在国外市场表现显著，而国内由于价格因素，邻苯二甲酸酯类增塑剂仍将被大量使用。

In order to study on the QSRR of fatty esters, 100 fatty esters were optimized by semiempirical calculations AM1, then calculated them by quantum chemistry algorithnl and the technique of molecule graphics and AM1 to acquire the Kier index and Kappa shape index.

为了研究脂肪酯的构效关系，应用半经验量子化学AM1法得到了100种脂肪酯分子的优势构象，利用量子化学算法和分子图形学技术获得Kier指数和Kappa形状指数，再在分子拓扑理论的基础上，提出了一个修正的拓扑染色指数mL，用多元回归技术建立了脂肪酯化合物的结构与色谱保留值的相关性模型。

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。