选择反应

Twenty-six eyes which appeared rejection after allograft penetrating keratoplasty between April 2003 and April 2004 in Shandong Shi'erming Eye Hospital were collected, including 16 males and 10 females, 9 cases were repeated relapsing viral keratitis, 8 cases were traumatic posterior corneal leucoma, 5 cases were corneal decompensation caused by various intraocular surgery, 2 cases were congenital leucoma, and 2 cases had other symptom. The rejection occurred at 2 month to 2.5 years after operation. Among them 19 cases were transferred to our hospital and asked adding traditional Chinese therapy because western medicine was ineffective in other hospital.

选择山东施尔明眼科医院2003-04/2008-04接诊的同种异体穿透性角膜移植后发生排斥反应病例26例，男16例，女10例，反复发作病毒性角膜炎9例，创伤性后角膜白斑8例，各种内眼手术引起角膜失代偿5例，先天性角膜白斑2例，其他2例，上皮型免疫排斥反应、基质型免疫排斥反应、内皮型免疫排斥反应均有，排斥反应发生在术后2个月～2.5年，其中19例是外院西药治疗无效而转入山东施尔明眼科医院要求加用中医治疗。

Then it summarizes the literatures under the structure. The content includes:(1) the regulation issues in the process of information disclosure, including the explanations of information disclosure control, research of the accounting systems, the mechanism of regulation and legal responsibility;(2) supply of information disclosure, composing accounting policy research and unconstraint disclosure research;(3) research of information intermediaries, including auditors and financial analysts;(4) research on the results of information disclosure, mainly on the reaction of constraint and unconstraint information disclosure.

然后，按照此框架，对信息披露的研究文献进行综述，包括：①信息披露中的监管问题，包括信息披露管制解释、会计制度选择研究、监管体系及法律责任研究；②信息披露的供给问题，包括会计政策选择研究、自愿性披露研究等；⑧信息中介的研究，包括审计师、财务分析师等信息中介研究；④信息披露后果研究，包括强制披露的市场反应研究和自愿性披露的市场反应研究。

The E-TOF will also be feasible and practical to assist chemists in screening the optimal reaction condition or evaluating the overall efficiency of different catalytic systems for a specific asymmetric reaction.4.For the first time,we explored chiralγ-hydroxy-α,β-acetylenic esters,which were prepared via asymmetric alkynylation,as key intermediates to the synthesis of chiralγ-butyrolactones. This convergent and enantioselective approach to chiralγ-butyrolactones is practical and easily handled with protecting group free.

这一概念包括反应产率、对映选择性、配体用量以及反应时间四个重要反应参数，不仅适用同一反应不同催化体系的横向综合性评价，而且适用于某一特定反应催化体系的优化过程，有助于研究人员选择最佳的反应条件。4、我们发展了以手性γ-羟基-α，β-炔酸酯为关键中间体完成了手性γ-丁内酯类天然产物的对映立体选择性全合成，该关键中间体能够以我们的催化体系方便的对映选择性合成，之后的官能团转换方法成熟，易于操作，无需进行繁琐的官能团保护和脱保护过程，绿色经济。

The key advantages of the Suzuki cross-coupling are the mild reaction conditions and the commercial availability of the diverse boronic acids that are environmentally safer than the other organometallic reagents.

催化剂是suzuki偶联反应当中一个重要的因素，选择合适的催化剂不仅能够使反应条件变得比较温和而且能够提高反应产率，甚至能使原本不能发生的反应变为可能。Suzuki偶联反应的催化剂通常由两部分组成：钯源和配体。

To be different from the already chloromethylation catalyst, it has a certain amount of moisture wet, which will not produce huge amounts of doughtic cancerogenic chloromethyl methyl ether during and after the reaction.4,4\'-bisbiphenyl, 1,4-bisbenzene, 1,4-bis(chloro- methyl)-2,5-dimethylbenzene, 1,5-bis-2,4-dimethylbenzene, 4-(chlor- omethyl)-1,2-dimethylbenzene, 1,2-bis-4,5-dimethylbenzene, 5,8-bis-1,2,3,4-tetrahydronaphthalene, 3,3\',5-tris-4,4\'-bisbiphenyl and 3,3\', 5,5\'-tetrakis-4,4\'-bisbiphenyl were synth- esized by using this new catalyst. Results indicated that when the reaction temperature was 55～60℃, the reaction time was 12h, the catalyst which consists of the concentration of 80%H_2SO_4, HAc and Lewis acid, the amount of Lewis acid 0.15 mol(nLewis:nbiphenyl=1.5:1), yield of biphenyl chloromethylation product 4,4\'-bis(chrolomethylbiphenyl can reach a maximum 85%.

采用这种催化体系完成了4，4′-二氯甲基联苯、对二氯甲基苯、1，4-二氯甲基-2，5-二甲基苯、1，5-二氯甲基-2，4-二甲基苯、4-氯甲基-1，2-二甲基苯、1，2-二氯甲基-4，5-二甲基苯、5，8-二氯甲基-四氢萘、3，3'，5-三氯甲基-4，4'-二甲基苯和3，3'，5，5'-四氯甲基-4，4'-二甲基苯的合成，结果表明：在反应条件为：反应温度55～60℃，反应时间12h，选择80%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.15mol(和原料比为1.5：1)，反应效果最好，联苯氯甲基化产物(4，4′-二氯甲基联苯)收率为85%；在反应条件为：反应温度70℃，反应时间8h，80%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，苯的氯甲基化产物收(来源：ABd0C论文eded网www.abclunwen.com)率为75%；在反应条件为：在反应条件为：反应温度40℃，反应时间10h，60%H_2SO_4和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，对二甲苯氯甲基化产物(1，4-二氯甲基-2，5-二甲基苯)收率为78.5%；在反应条件为：反应温度35℃，反应时间10h，60%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，间二甲苯氯甲基化产物(1，5-二氯甲基-2，4-二甲基苯)收率为81.5%。

Firstly, a series of organic molecules which use phthalimido group as electron acceptor, N as electron donor, COO~- as eletrofugal group were synthesized based on SET-promoted photocyclization processes. These compounds were irradiated by 500 W ultraviolet under nitrogen atmosphere in room temperature. After filtration of the photochemical character of these molecules, substrate S1 and S2 were selected as appropriate model reactants. Secondly, the monosubstituted derivatives at the 6-position ofβ-cyclodextrin were synthesized as chiral template of photocyclization.

首先，以单电子转移机理为指导，设计了一系列以邻苯二甲酰亚胺基为电子受体、N为电子给体、羧基为离去基团的光环合反应底物，这些化合物在氮气保护下以500瓦紫外光室温下进行光照反应，对这一系列的分子的反应情况进行了研究与筛选，最终选择底物S1和S2作为研究光环合反应中立体控制方法的模型底物；其次，又合成了一系列6-位单取代β-环糊精，以此作为光环合反应的手性模板。

By use of titration analysis, the thesis investigated various factors such as isocyanate, PE molecular weight, reacting substance molecular ratio, reacting temperature and time etc. influencing upon prepolymerization step. It was found that 2, 4-tolulene diisocyanate and 4, 4'diphenylmethane diisocyanate is more rapidly reacted with PE600 than HDI. With PE molecular weight increasing, the reacting temperature or time should be raised or extended relevantly. Thus PE2000+2HDI pre-polymerization should be better carried out under some catalyst, for example, Triethylene diamine , Dibutyltin dilaurate and Tin octoate were used.

首先采用滴定分析方法对WRPU预聚反应的影响因素进行了研究：芳香族二异氰酸酯TDI、MDI比脂肪族二异氰酸酯HDI反应活性高，其中TDI在反应初始阶段的反应速率比MDI快，不过随着反应的进行，MDI比TDI反应速率加快，这主要是因为TDI分子中的两个-NCO反应活性差异大所致；二元醇分子量越大，反应速度越慢；聚醚二元醇比聚酯二元醇的反应速度快；当分子量超过2000的二元醇与HDI进行预聚反应时，需借助适当的催化剂来加快反应速度，从而使预聚反应能够顺利进行，分别选择DABCO、TOA和DBDTL三种催化剂进行催化反应，发现不同的催化剂，其催化效果相差较大。

The optimum technical parameters were obtained as follows:bromating temperature is 15℃,solvent is methyl arcohol, bromating agent is BrCl,the molar ratio of 4-hydroxy-benzaldehyde to BrCl is 1:1.15,reaction time is 2.5 hours.

其工艺参数优化如下：溴化时反应温度选择15℃，溶剂选择甲醇+乙酸甲酯，溴化剂选择氯化溴，对羟基苯甲醛与氯化溴之比为1∶1.15，反应时间选择2.5个小时，滴溴时间约半个小时。

To the product yield is mainly studied in the brominating process, and the best synthesizing process conditions is obtained; the effect of the selection, quantity of the solvent, the reaction temperature, reaction time, and the catalyzer to the product yield is researched in the process of ketalization and the relative preferable process conditions has been got.

在脱溴反应中，主要研究了溶剂的用量、溶剂配比、物料配比、反应时间和反应温度等对目标产物得率的影响；在选择性溴化反应中，主要研究了溶剂和溴化剂的选择、物料配比、溶剂的用量等参数对产物质量和得率的影响，最终得到了合成的最佳工艺条件；在缩酮化反应中，主要研究了溶剂的选择、溶剂的用量、反应温度、反应时间和催化剂的选择等参数对产物得率的影响，并得到合成的较佳工艺条件。

The aim of this study was to reveal the host-choice mechanism of the seed beetle, Callosobruchus maculatus , under a condition when different hosts are provided.

本文主要探讨四纹豆象在面临不同种类之寄主时，其产卵的寄主选择反应为何？

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

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如果有任何问题，你可以随时联系我。