羟基

1H-NMR and UV analysis show that, after reaction, benzene ring in the structure unit of the alkali lignin is steady, carboxyl, carbonyl and methoxyl all have reduced in different extent, while aliphatic and phenol hydroxyl have increased.

1H-NMR和UV光谱分析显示反应后碱木质素的结构单元中苯环结构稳定，羰基、羧基、甲氧基有所减少，醇羟基和酚羟基的量增加了。

The relative stabilities and probable proton transfer in isolated and monohydrated 2-hydroxyimidazole molecules have been studied in gas phase using ab initio (MP2/6-31＋G *) method.

采用从头算方法在MP2/6-31＋G*水平上研究了2-羟基咪唑分子在孤立分子和一水合物的异构体的相对稳定性和可能的质子迁移反应，分析了一个水分子的参与对2-羟基咪唑分子异构体的相对稳定性和质子迁移速率的影响，采用Monte Carlo模拟方法研究了反应体系在水溶液中反应的溶剂化效应。

Silica gel column and reversed-phase C-18 column were employed to purify and separate monohydroxy intermediates.

此外，对DKR催化双羰基底物还原得到的3R，5S-双羟基产物进行纯化，再通过羟基保护和保护基的去除，以用于他汀类药物的手性侧链制备。

N,N '- ditertbutyl nitroxyl radical, 2, 2,6,6- tetramethyl-4 - hydroxyl piperdinehy droxylamine and its nitroxyl radical, as inhibitors of the BPO- initiated copolymerization of styrene (M 1 ) with acrylonitrile (M2 ), at 60℃,has been studied.

研究了二叔丁基羟胺，二叔丁基氮氧自由基，2，2，6，6－四甲基－4－羟基哌啶羟胺和2，2，6，6－四甲基－4－羟基哌啶－1－氧自由基对过氧化苯甲酰60℃引发的苯乙烯（M1）－丙烯腈（M2）共聚合的阻聚行为。

The measurement of nicotine and its major metabolites cotinine and trans-3 -hydroxicotinine together with other minor metabolites (e.g., cotinine N-oxide, cotinine, and trans-3 -hydroxicotinine glucuronides) in conventional and nonconventional biological matrices has been used as a biomarker to assess the exposure to environmental tobacco smoke during childhood.

常规和非常规性生物基质内尼古丁、尼古丁主要代谢产物可替宁和反式-3-羟基可替宁及其他代谢产物（可替宁N-氧化物，可替宁和反式-3 –羟基可替宁葡萄糖苷酸）的检测可作为评价儿童期环境烟草烟雾暴露的一个生物标志物。

In pH=2.0 sulfuric acid solution, 2,2′bipyridine, an almost nonluminescent compound was transformed into a highly fluorescent compound (λex=340 nm,λem=430 nm) when attacked by ·OH generated by Fenton reaction.

在酸性介质中，Fenton反应产生的羟基自由基能将几乎无荧光的2，2′-联吡啶氧化成强荧光物质，羟基化产物的最大激发和发射波长分别是340 nm和430 nm。

In the hydroxylation of phenol with H〓O〓 in the presence of Ti-ZSM-5, water is best solvent. It produces catechol and hydroquinone simultaneously, and catechol/hydroquinone ratio is approximately 0.85. The results show H〓O〓 utilization ratio increase 14%, when nonoxidizable weak acid HAc is added into the reaction system. Under the conditions of Ti-ZSM-5 as catalyst, phenol/H〓O〓 ratio being 10, a little HAc, temperature 75℃, reaction time 6h, H〓O〓 utilization ratio reaches 74. 6mo1% in the reaction.

对Ti-ZSM-5催化苯酚羟基化的研究结果表明，水是最好的溶剂，羟基化有邻、对苯二酚两种产物，并且邻苯二酚/对苯二酚摩尔比可维持在～0.85左右；向反应体系中加入非氧化性弱酸性助剂HAc时，H〓O〓有效利用率较未加入助剂时可提高14mol%；当催化剂用量为8g/100g苯酚、苯酚/H〓O〓比为10、反应温度75℃、添加少量HAc的条件下，反应6h后，H〓O〓有效利用率可达74.6mol%。

Firstly, 2-Hydroxy-4-octyloxybenzophenone was synthesized from 2,4-dihydroxybenzophenone and octyl chloride in the presence of N-octyl-diethanolamine borate as ion liquid, and 2-Hydroxy-4-methyloxybenzo phenone was synthesized from 2,4-dihydroxybenzophenone and dimehylsulfate in the presence of N-octyl-diethanolamine borate as catalysis.

首先作为离子液体催化合成了2-羟基-4正辛氧基二苯甲酮和作为相转移催化剂合成了2-羟基-4甲氧基二苯甲酮。

MAIN OUTCOME MEASURES: In vivo degradation performance and ossific capability of PHBV copolymer as well as energy-dispersive X-ray analysis and elemental quantitative assay in bone defect regions.

主要观察指标：①聚羟基丁酸/羟基戊酸共聚酯的体内降解性能和成骨能力。②骨缺损区X射线能谱分析及元素定量测定。

The scavenging effects of different solvent extracts on hydroxyl radicals produced by the system were compared by phenanthroline oxidation method, and change conditions of scavenging rate of hydroxyl radicals with the prolonging of time were studied.

方法］采用超声波提取法，分别以蒸馏水、50%乙醇和95%乙醇为溶剂，在40℃条件下提取30 min，获得了薄荷的不同溶剂提取物，并以邻二氮菲氧化法比较了不同溶剂提取物时体系产生的羟基自由基的清除作用，并研究随时间延长羟基自由基清除速率的变化情况。

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。