酯

And thus, either one of the two geometrical isomers can be obtainedat will in high yield with high stercoselectivity,Two different stereoselectivities are displayed in thereactions of arsonium and telluronium benzylides with α,β-unsaturated esters and amides.

发现了苄基胂、碲叶立德在与α，β-不饱和酯、酰胺的环丙烷化反应中表现出不同的立体选择性，肉桂基胂、碲叶立德与α，β-不饱和酯反应时亦是如此。

Two kinds of ashless and non-phosphorus additives, hydroxyl-containing dithiocarbamate derivatives were prepared.

合成了2-乙羟基-吗啡啉二硫代氨基甲酸酯和2-乙羟基-二正丁胺基二硫代氨基甲酸酯两种添加剂。

The investigation also showed that, the antioxidants with same action mechanism, for example, as both radical scavengers, phenol and amine antioxidants are synergistic; but the synergistic effects between two antioxidants with different action mechanism, such as radical scavenging phenol and amine antioxidants, and hydroperoxide decomposing ashless dithiocarbamate, are much stronger, and the heterosynergism between dithiocarbamate and alkylated diphenylamine is outstanding, which can serve as high temperature ashless high performance antioxidant combination; the heterosynergism among three antioxidants with three different action mechanisms, for example, the tri-component combination of alkylated diphenylamine, zinc dithiocarbamate and organic molybdate ester, can achieve excellent antioxidation performance.

研究还表明，具有相同抗氧机理的不同抗氧剂，如酚类和胺类抗氧剂，具有协同作用；不同作用机理的两抗氧剂之间，如自由基清除剂和氢过氧化物分解剂，具有更好的抗氧化协同效果，其中，无灰氨基甲酸酯与烷基化二苯胺抗氧剂具有最佳的抗氧协同效能，可成为高温无灰抗氧剂应用的一个很好选择；不同抗氧机理的三种抗氧剂复合，如烷基化二苯胺，氨基甲酸锌和有机钼酸酯组成的三元复合抗氧剂，具有更为优秀的抗氧化性能。

Objective To evaluate the biocompatibility of poly (lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol) tri-block copolymer in vitro.

目的 对自主研制的三嵌段骨基质材料－聚丙交酯／乙交酯／天冬氨酸－聚乙二醇的体外生物相容性进行评价。

Objectives: To investigate the effects of adhesion and proliferation of bone mesenchymal stem cells in the surface of lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol PLGA- tri-block polymer scaffolds, try to find a new biomaterial to induce seed cells in vitro for bone tissue engineering.

目的：探讨大鼠骨髓间充质干细胞BMSCs在聚丙交酯/乙交酯/天冬氨酸-聚乙二醇三嵌段多元共聚物 PLGA-表面粘附、增殖的情况，为组织工程学体外诱导种子细胞生长提供新的生物材料。

C.fatigans to Deltamethrin had a high resistance level in different regions of Jiangxi Province;The resistance to DDVP and Acetophenate showed apparent; The resistance to Bassa were not obvious.

摘 要 目的：探讨我省不同地区致乏库蚊对化学杀虫剂的抗药性现状。方法：采用浸渍法测定致乏库蚊幼虫的LC50。结果：不同地区致乏库蚊对溴氰菊酯均达到相当高的抗性水平；对敌敌畏和三氯杀虫酯的抗药性明显；对仲丁威的抗药性尚不明显。

The photoproducts of CCU in organic solvents have also been identified with HPLC- and GC-MS. The photoproducts identified in methanol are isocyanato bezene, 4-chlorophenyl isocyanate, 2-chloro benzamide, chlorobenzene, 4-chlorophenyl urea, N-phenyl methylcarbamate, N-(4chlorophenyl) methylcarbamate, and 2-chloro-N-(4-chlorophenyl) benzamide.

对灭幼脲在各种有机溶剂中的光解产物作HPLC/UV和GC-MS鉴定，发现其在甲醇中的光解产物含有：异氰酸苯酯、对氯苯基异氰酸酯、邻氯苯甲酰胺、氯苯、对氯苯基脲、N-苯基氨基甲酸甲酯、N-氨基甲酸甲酯、以及N-邻氯苯甲酰胺等。

Replacement of one benzimidazole fragment with benzothiazole or benzoxazole and optimization of the structure to create the new frame of the compounds were also carried out with the exception to find more potent compounds. The purpose of design and synthesis of these compounds is to investigate the QSAR of this class of compounds with the inhibition of HCV NS3/NS4A protease and eventually to develop more potent inhibitors.

本文首次采用了丙二酰胺与邻芳二胺在微波辐射下制备对称性双芳并唑甲烷化合物、用芳并唑-2-乙酸乙酯与邻芳二胺在微波辐射下制备非对称性双芳并唑甲烷化合物、用4-取代噻唑-2-乙酸乙酯与邻芳二胺在微波辐射下制备非对称性(4-取代-噻唑-2-基)(1H-芳并咪唑-2-基)甲烷化合物等合成路线，共合成了48个目标化合物，其中41个为新化合物，用~1HNMR，ESI-MS，FT-IR，元素分析对这些化合物进行了全面表征，确定了这些化合物的结构，并对部分化合物进行了~(13)CNMR分析。

Betulin and betulinic acid are remarkable natural products. They are obtained from a variety of botanical sources.

白桦酯醇和白桦酯酸是非常有价值的天然产物，它们可以从丰富的植物资源中获得。

Betulin, betulinic acid and many of their derivatives exhibit great promise as bioactive agents for the treatment of HIV infection and cancer.

白桦酯醇、白桦酯酸及其衍生物作为生物制剂在HIV和癌症治疗方面表现出了巨大的潜能。

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。