羟基

Crystal structural analysis reveals that, because water molecules bond to Cu atoms, the dhbd ligand can only adopt a hydroxyl oxygen atom to bridge two reversed U-shaped subunits into a novel centrosymmetric dual-U-shaped tetranuclear Cu structure. Each U-shaped frame consists of two crystallographically distinct Cu atoms, two dpphen ligands and one coordinated water molecule.

晶体结构分析表明，由于水的配位阻断， 2，3-二羟基丁二酸根仅通过单羟基氧桥联两个U形双核亚单元形成具有一个对称中心的双U形四核结构，其中U型亚单元包含晶体学上不对称的2个Cu原子、1个2，3-二羟基丁二酸根、2个4，7-二苯基-1，10-邻菲咯啉和1个配位H2O分子。

A method for the preparation of microcellular elastomeric polyurethane foams from a reaction mixture comprising a polyisocyanate component containing at least 85% by weight of 4,4'-diphenylmethane diisocyanate or a variant thereof, a polyol composition comprising at least one polyoxyalkylene polyol having an average nominal hydroxyl functionality of from 2 to 6, an average hydroxyl equivalent weight of at least 1300 and an average oxyethylene content of between 50 and 85% by weight, water, a chain extender having an average hydroxyl equivalent weight of from 15 to 250 and optionally a crosslinking agent, the hardblock-content being more than 45% by weight.

本发明是有关一种制备微孔弹性聚氨基甲酸酯泡沫体的方法，其反应混合物包括：一种含至少85重量％的4，4′－二苯甲烷二异氰酸酯或其变体的聚异氰酸酯组分，一种多元醇组合物，其包含至少一种平均标称羟基官能度从2至6、平均羟基当量至少1300且平均氧乙烯含量介于50至85重量％之间的聚氧亚烷基多元醇，水，一种平均羟基当量为15至250之增链剂，以及视需要使用的交联剂，该硬性嵌段－含量（hardblock-content）大于45重量％。

Ib was synthesized by condensation of phthalic anhydride with 2-methylresorcinol in fused AlCl〓/NaCl (5∶1), followed by selective acetylation, methylation, NBS bromination and condensation with sodium ethoxide.

邻苯二甲酸酐在熔融的三氯化铝-氯化钠(5：1)中和-2，6-二羟基甲苯环合得1，3-二羟基-2-甲基蒽醌〓后经选择性乙酰化、甲基化、NBS溴化、乙醇钠缩合得1-甲氧基-2-乙氧甲基-3-羟基蒽醌。

Hydroxyacetic acid was synthesized by glycolonitrile in the presence of H2SO4 , and it was separated by applying extraction based on chemical complexation and solvent method.

以羟基乙腈为原料，在酸性条件下水解合成羟基乙酸，并采用络合萃取法和溶剂溶解法分离羟基乙酸。

The review highlights the technical developments in the identification,quantification and separation of α-hydroxyacetic acid,especially solvent extraction and synergistic extraction.

文章比较了各种羟基乙酸定性及定量分析方法，综述了羟基乙酸分离方法，特别是溶剂萃取和协同萃取效应。最后，分析了羟基乙酸的开发前景。

The advantages of α-hydroxyacetic acid biosynthesis over traditional chemical conversion are wide range of reaction condition,high conversion ratio and green process.

化学法生产羟基乙酸存在原料消耗大、产品收率低、环境污染严重等缺点；生物法合成羟基乙酸条件温和、底物转化率高，为绿色合成羟基乙酸提供强有力的技术支持。

This indicates that the interpolymer complexation resulting from thestrong specific interactions has overcome the surface segregation effect caused by thedifferences in the surface free energies.

羟基和吡啶基之间的氢键概率随着羟基含量的增加而迅速增加，在高羟基含量(49 mol％)的情况下，几乎达到1.0，这也从另一个方面说明了在络合物中，链段配对的趋势很强。

The SERS spectra of isoquinoline and its six derivates 3 -isoquinolinecarboxylic hydrate (Ⅱ, 1-isoquinolinecarboxylic acid, methyl 3-isoquinolinecarboxylate, isocarbostyril, 5-hydroxy-isoquinoline and 1, 5-isoquinolinediol were obtained by mixing the chemicals with silver colloid.

应用SERS技术，我们获得了异喹啉及其六种衍生物3-羧基异喹啉(Ⅱ，1-基异喹啉，甲基-3-羧基异喹啉酸酯，1-羟基异喹啉，5-羟基异喹啉和1，5-二羟基异喹啉的喇曼光谱。

Prophenoloxidase is a key enzyme for mediating melanotic encapsulation of oocysts,which may be transformed into active phenoloxidase by limiting proteolysis.

而前酚氧化酶(Prophenoloxidase，PPO)是介导卵囊黑化包被反应的一种关键酶，活化后可催化酪氨酸羟基化为二羟基苯基丙氨酸，二羟基苯基丙氨酸和多巴胺可进一步氧化为具有活性的苯醌活性，苯醌即可介导蛋白交联并聚合成黑色素层固定、隔离或杀死入侵的病原体。

Then, we studied the pathway of bacterial metabolism of Bpa and identified three kinds of metabolon of p-Hydroxy benzoic acid , p-Hydroxy benzaldehyde and p-Hydroxy acetophenone.

其次，利用现代分析化学技术研究Pseudonomas sp.W2对Bpa的代谢途径，发现对羟基苯甲酸、对羟基苯甲醛、对羟基苯乙酮为三种中间代谢产物。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。