羟基

Their structures were identified by physico-chemical properties and spectral analysis. RESULTS Seven compounds were isolated as kaempferol,quercetin,astragalin,isoquercitrin,kaempferol-3-O-β-D-glucuronic acid methyl ester,4-hydroxybenzonic acid,hentriacontane.

结果分离得到7个已知化合物，分别为山柰酚、槲皮素、山柰酚-3-O-β-D-吡喃葡萄糖苷、槲皮素-3-O-β-D-吡喃葡萄糖苷、山柰酚-3-O-β-D-吡喃葡萄糖醛酸甲酯、对羟基苯甲酸、三十一烷。

The procedure can be simply described as follows: heteroatoms source such as AlCl3 or TiCl4 is added into the reaction system together with silica source and surfactant and heteroatom species will uniformly dispersed in the form of ions.

调节pH值的目的在于使杂原子物种不再以离子形式而以酸根形式存在从而可以与孔壁上的硅羟基通过缩合结合在一起从而进入介孔骨架。

Not only the hydrogen atom of hydroxyl but also the hydrogen atom of the methyl group can transfer to the N atom of heterocycle.

不但甲醇分子羟基上的H可以作为供体质子，而且甲基上的H也可以作为供体质子而转移到芳香环的杂原子N上。

The synthesis methods of nipagin esters catalyzed by sulfuric acid , p- toluene sulfonic acid , ferric sul-fate hydrate, ferric chloride hexahydrate, aluminium chloride hexahydrate, rare earth compound, solid super acid and heteropoly acid were reviewed.

评述了采用硫酸、甲苯磺酸、合硫酸铁、水合三氯化铁、水合三氯化铝、土化合物、体超强酸和杂多酸等催化剂催化合成对羟基苯甲酸酯的方法。

Using Hexamethylenetetramine as the catalyst and P-Hydroxyanisole as the inhibitor, glycidyl methacrylate were prepared by two-step method successfully.

本论文以六次甲基四胺为催化剂，对羟基苯甲醚为阻聚剂，采用酯化闭环两步法制备出甲基丙烯酸缩水甘油酯。

In the crystal structure of the title compound,the independent p-hydroxybenzoic acid and hexamethylenetetramine molecules are arranged alternately and constructed the three-dimensional hydrogen-b.

在标题化合物的晶体结构中独立的对羟基苯甲酸分子和六次甲基四胺分子组交错排列，借助多种氢键形式形成三维氢键网络结构，其中弱氢键扮演着重要的角色

The activity of pyruvate formate-lyase and pyruvate dehydrogenase accounts for the observed production of formate, acetate, ethanol and acetoin. In 1978, Hillman isolated one of the mutants of Streptococcus mutans which lack the enzyme activity of dehydrogenase.

当外源性糖丰富的时候，果糖-1，6-二磷酸增加，使LDH活化，90%以上的葡萄糖被转化为乳酸；外源性糖供应不足时，通过丙酮酸甲酸裂解酶和丙酮酸脱氢酶作用产生甲酸、乙酸、3-羟基丁酮和乙醇。

The 5 type of HA have different values of E465/E665, ranging from 3 to 5. They belong to the category of HA with a large number of molecules. Among them, the Forest Soil HA from Jingyun Mountain has the maximum amount of E465/E665, which means that it has the minimum extent of humification, benzene derivative in HA and molecule complexity.

红外光谱分析表明：供试5种不同土壤腐殖酸红外光谱均出现相似的吸收峰，反映出它们具有相似结构，均含有苯环和酚羟基官能团；但不同腐殖酸的红外光谱也有一定差异，2900cm~(-1)，1720cm~(-1)、1(来源：bcABb1C论文网www.abclunwen.com)520cm~(-1)、1366cm~(-1)。

This is exactly opposite to the order of E465/E665 in HA and the order ofΔ~ K. It shows that the larger the extent of humification, the larger the effect for reducing the rate of Phoxim hydrolysis, because the extent of HA humification is closely related to the extent of benzene in HA and the amount of carbonyl, aryl, phenolic hydroxide.

因腐殖酸腐殖化程度与腐殖酸芳构化程度、羧基、羰基和酚羟基的含量等相关，因此用腐殖酸腐殖化程度反映腐殖酸对农药水解作用大小比仅用腐殖酸中有机碳含量等因素反映更为合理。

This FCA labeled DNA probe is used to hybridize with the sample DNA sequence accumulated on the surface of a graphite electrode.

系统讨论了生物体内产生羟基自由基必不可少的Fe〓和H〓O〓的浓度对DNA损伤作用的影响，以及保温时间对DNA损伤作用的影响。

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。