二聚的

The results showed that POD activity increased at first and then decreased in the skin and flesh of root. The peak occurred at 40 d and 60 d in the skin and flesh, respectively. POD activity in the skin was higher than that in the flesh at 30 d and then contrary results were observed. The higher POD activity was, the more POD isoenzyme was. The pattern of POD isoenzymes was different between skin and flesh at different vegetative growth stages. POD isoenzymes in the skin were composed of five monomers and four dimers while five dimers or two monomers, two dimers and one tetramer in the flesh. POD isoenzymes in the root were mainly acidic. POD localized mainly in the cell walls of periderm, cambium, xylem ray, xylem vessels and primary xylem.

结果显示，心里美萝卜营养生长期肉质根的皮和肉中POD活性均先升高后降低，分别在播种后第40 d和60 d出现峰值，30 d时皮中POD活性高于肉，之后则相反，酶活性最高时同工酶数目也最多，不同时期，皮和肉中同工酶种类不同；皮中POD同工酶由5个单体和4个二聚体组成，而肉中由5个二聚体或2个单体、2个二聚体和1个四聚体组成，均以酸性同工酶为主；组化定位显示POD主要分布在肉质根的周皮、形成层、木射线、木质部导管和肉的初生木质部等的细胞壁附近。

The tryptophan residues play important roles in DNA photoreactivation catalyzed by CPD photolyases. We have investigated the action mechanism concerning Trp in DNA photoreactivation, and obtained the results as follows: 1 We proposed a mechanism of photosensitized splitting of CPDs by Trp and Trp-containing peptides. 2 Quantum yields of splitting of the model compounds that a Trp linked covalently a CPD were obtained under 290 nm light in various solvents, these values changing with solvent, range from 0.01 to 0.5. 3 Utilizing pulse radiolysis technique, splitting processes were observed in aqueous solution of the CPDs with hydrated electron and some oxidative species (such as hydroxyl radical, bromic radical and azide radical), and obtained their rate constants. In the case of interaction between CPD and hydrated electron, splitting of the CPD anion, and pyrimidine anion transfer an electron to FAD or Rf, were observed. The process rate was slower one order more than that in photolyase. Minor, but highly mutagenic UV-light-induced lesions are (6-4) photoproducts, which are repaired by (6-4) photolyases. These enzymes, discovered in 1993, are not well characterized and their mechanism is still under investigation.

我们研究它的作用机理，获得以下结果：1）建立了色氨酸及其肽对嘧啶二聚体光敏化裂解的直接修复作用机理模型；2）获得了色氨酸共价键连接于嘧啶二聚体的化合物在多种溶剂中290nm光辐照裂解的量子效率，其值随溶剂而变化，范围在0.01-0.5；3）运用脉冲辐解观察到嘧啶二聚体与水合电子和一些氧化性的自由基作用裂解过程，得到相应速率常数；对二聚体与水合电子作用发生裂解以及向FAD返还电子的过程进行了体外模拟；4）（6-4）光解酶的作用机理中一个关键假定是氧杂环丁烷中间体在接受电子后能自发裂解，恢复二嘧啶的结构。

The results show that isobutene oligomerization is fast liquid-solid reaction. Under the temperature of 80 ℃～120 ℃ and pressure of 2.0 MPa, the products of oligomerization are mainly dimers and trimers of isobutene. The yield of trimers is higher than that of dimers and the mass fraction of trimers decreases with reaction temperature increasing. The yield of tetramers is much lower than that of dimmers and trimers. The tetramers are formed by reaction of isooctenes and C8 carbonium ion.

结果表明，异丁烯齐聚反应为快速液固相催化反应，在80 ℃～120 ℃，2.0 MPa的实验条件下，反应产物主要是异丁烯的二聚物和三聚物，且三聚物的收率远高于二聚物，两者的浓度比值随反应温度的升高而下降；少量四聚物的生成主要源于碳八烯烃与碳八正碳离子的反应。

The reactions involved in the co-curing are: cyclodimerization and cyclotrimerization of cyanates, polyetherfication of epoxy groups and cyclotrimerization of cyclic dimers, as well as the formation of oxazolidinone rings.

反应历程首先是氰酸酯发生自聚反应形成二聚体或三聚体，然后二聚体可进一步共聚形成三嗪环，此过程伴随着环氧基的聚醚反应，最后是三嗪环与剩余的环氧基反应形成NFDA1唑烷酮。

In order to decrease copolymerization loss of isoprene during thermal dimerization of cyclopentadiene in C5-fraction,the effect of three inhibitors,diethylhydroxylamine,p-tert-butylcatechol and o-nitrophenol,on dienes' polymerization in the process was investigated by experiment with sealed glasstube.

为减少C5馏分环戊二烯热二聚过程中异戊二烯的聚合损失，采用封管实验方法考察了添加阻聚剂二乙基羟胺、对叔丁基邻苯二酚、邻硝基苯酚对热二聚过程中各二烯烃组分聚合程度的影响。

The synthesization technics of MPEG- MAA was studied in this paper,which is an important intermediate used for preparation of polycarboxylate superplasticizer.

本文对制备聚羧酸系减水剂的重要中间体——甲基丙烯酸聚乙二醇单甲醚酯的合成工艺进行了研究，考察了反应时间、催化剂对甲苯磺酸的用量、阻聚剂对苯二酚的用量、反应温度及甲基丙烯酸与聚乙二醇单甲醚的用量比对酯化率的影响。

The dimer acid and polyamide resin synthesis technology which use Sichuan bentonite as primarily catalyst by our company researched and developed greatly surpassed the domestic same industry on product quality and product yield (dimer acid colour:≤7#, viscosity: 5000~10000 cp/250C can control at will, the yield is higher than the same industry 8~10%). Serialized product plan: dimer acid, monomer acid, co-soluble polyamide resin, alcohol soluble polyamide resin, liquid polyamide resin and polyamide hotmelt adhesive, let the enterprise can adjust the product mix nimbly and can respond to market easily in the intense market competition.

公司研发的以四川膨润土为主催化剂的二聚酸合成技术，在产品质量和产品收率上均大大优于国内同行业（二聚酸色泽≤7#，粘度在5000～10000cp/250C之间可调，收率高于同行业8~10%）；系列化的产品方案：二聚酸、单体酸、共溶聚酰胺树脂、醇溶聚酰胺树脂、液体聚酰胺树脂及聚酰胺热溶胶，让企业在激烈的市场竞争中，可灵活调整产品结构，做到应对市场游刃有余。

Calcium dimer acids and zinc dimer acids were prepared by double decomposition reaction,and their structures were identified by IR.Their effects on heat stability of PVC were tested by way of Congo Red Method and Heating Method.Calcium dimmer acids and zinc dimmer acids were compared with traditional calcium stearate and zinc stearate.

通过复分解法制备了二聚酸钙和二聚酸锌，并通过红外检测证明了其结构；采用刚果红法、热烘法研究了二聚酸钙和二聚酸锌对PVC的热稳定作用，并与传统的硬脂酸钙、硬脂酸锌热稳定剂作了比较。

The catalyst for IB dimerization, reactive site, reactive mechanism and dynamics research date was reviewed in this paper and try to explain the mechanism of selectivity enhancing by adding Tertiary butyl alcohol during IB dimerization and provide reference for the study of dimerization afterwards.

本文对异丁烯二聚催化剂、反应活性位、机理及动力学研究成果进行了综述，试图解释在异丁烯二聚时，加入的叔丁醇对二聚反应选择性提高的作用机理，为今后二聚反应的研究提供参考。

The optimum conditions for this reaction were confirmed: the mole ratios of the Lewis base and AlCl〓 with the electron-rich aromatic monomer are 1. 2 and 3. 4, respectively; 1, 2-dichloride ethane is the most suitable solvent in this reaction; The solution of the two reactants must be added slowly to a large amount of solvent containing catalyst under pseudo-high dilution conditions; The Lewis base, such as NMP, DMF are applicable in this reaction system.

在此理论的指导下，通过对单体结构的模拟，高选择性地合成了一种新型结构的芳香环状聚硫酯二聚体，对其结构进行了精确的表征，在不同溶剂中得到了该环状二聚体的单晶，单晶X-ray衍射表明该二聚体为环张力极小的大环化合物。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。