查询词典 retarding agent

To explore new synthetic methods, we set out a careful investigation of the reaction of benzimidazolium salt with many nucleophilic agents, including the active aromatic compounds and heteratom nucleophilic agents, and found that the quaternary C=N is not so active; when benzimidazolium salt is reacted with big nitrogen nucleophilic agent? phthalimide, it does not give the expected addition product, instead, produces N-alkyl phthalimide through alkyl-transfermation from benzimidazolium salt to phthalimide.

为了开发新的合成方法，研究了苯并咪唑盐与各种亲核试剂（活泼芳环与杂原子亲核试剂）的反应，发现苯并咪唑盐不与活泼芳环及杂原子亲核试剂发生2位加成反应；在与体积较大的位阻型N亲核试剂邻苯二甲酚亚胺反应时，未得到亲核试剂与极化的C＝N的加成产物，而是得到N烷基化的邻苯二甲酰亚胺，进一步研究表明，苯并咪唑盐将1（3）位N上的烷基转移给了邻苯二甲酰亚胺，并讨论了其反应机理和取代基，溶剂效应。

Seven of them have not been reported.Their structures were confirmed by IR,~1HNMR,MS,and element analysis. 4.Meanwhile,the green methylation procedure of imides was developed by using dimethyl carbonate as methylation reagent.A series of imides,for example,phthalimide,3,4-dibromo-maleimide and succincide were used for substrates.The effects of DABCO(1,4-diazabicyclo [2.2.2]octane)and DBU(1,8-diazabicyclo[5.4.0]undec-7-ene)as a catalyst in this kind of reactions were investigated.2-Bromo-3-(1-methylindolyl-3-yl)-1-methyl-1H-pyrrole-2,5-dione was prepared by using dimethyl carbonate,which further expanded the use of dimethyl carbonate,as a green agent in organic synthesis.

在以硫酸二甲酯为甲基化试剂对3，4-二溴马来酰亚胺进行N-甲基化反应合成3，4-二溴-N-甲基马来酰亚胺的同时，以碳酸二甲酯为甲基化试剂，对3，4-二溴马来酰亚胺、邻苯二甲酰亚胺、琥珀酰亚胺等酰亚胺类化合物的N-甲基化反应进行了研究；考察了1，4-二氮杂双环[2.2.2]辛烷，1，8-二氮杂双环[5.4.0]十一碳-7-烯、碳酸钾和四丁基溴化铵等作为催化剂对碳酸二甲酯N-甲基化反应的反应时间和收率等的影响，并应用碳酸二甲酯为甲基化试剂，合成了N-甲基-3-溴-4-(1-甲基-吲哚-3)-马来酰亚胺。

The synthetic route starts from penicillin G, peroxyacetic acid(8.5%) as Oxidizing Agent to get penicillin G sulfoxide; esterifided with p-nitrobenzyl bromine to synthesize penicillin G sulfoxide ester; we synthesize 3-exomethylenecepham sulfoxide ester with phthalimide potassium and 4A molecular sieve as acid scavenger to open the ring, SnCl_4 as catalyzation to close the ring. The yield is over 60%.

本研究采用的合成路线为：以青霉素G钾盐为原料，选用工业过氧化氢制备的过氧乙酸(22.3%)稀释至8.5%为氧化剂，氧化得青霉素亚砜；采用对硝基溴苄为酯化试剂，制备青霉素亚砜酯；以NCP(N-氯代邻苯二甲酰亚胺)为开环试剂，酞酰亚胺钾和4A型分子筛为酸清除剂，顺利开环；再经无水SnCl_4催化闭环得3-环外亚甲基头孢亚砜酯，最终产率在60%以上。

We also studied their inhibition on H2O2,UV-induced hemolysis of RBC. Sodium paeonol sulfonate was used as keep-freshing agent in tomato storage and vitamin C content, brix, acidity, weight loss, membrane permeability, soluble protein content, SOD andPOD activity was determined. The results were as follows: Paeonol and sodiumpaeonol sulfonate had remarkably inhibitory effects on Xanthmonas oryzaepv.oryzicda,Pseudomonas solanacearum Smith, Phyllosticta mali Pril.et Delac.and Rhizoctonia solani Kuhn.

在生物学活性方面，检测了丹皮酚及丹皮酚磺酸钠对植物病原菌的抑制作用，测定了其清除超氧阴离子自由基(O_2~-)、羟自由基的活性及对过氧化氢(H_2O_2)和紫外线诱导红细胞溶血的影响，并用丹皮酚磺酸钠对樱桃番茄进行了保鲜研究，测定贮藏期间番茄的维生素C含量、糖度、酸度、失重率、膜透性、可溶性蛋白含量、超氧化物歧化物及过氧化物活性等。

Therefore, the crude toxin of Phytophthora capsici can be used as selective agent in the following study.

由此表明，可用辣椒疫病病原菌粗毒素来进行辣椒抗疫病体细胞突变体筛选的研究。

On the basic of visual index and proportion of the eggs with eggwhite sticking shell and rotten heed, the stability of the pidan made by utilizing zine, copper,zine-copper mixture and nucleus material of pidan pickle agent was compared.

采用GB9694 -88标准比较了用锌法、铜法、铜锌合剂法、皮蛋腌制剂核心料法生产皮蛋的稳定性，以及皮蛋腌制剂核心料在不同季节，不同添加量按感观指标和粘壳、融头蛋产生的比例检验其稳定性。

X-ray diffraction showed that the hydroxy-chromium oligocations can be used as a stable pillaring agent after aging at 70 ℃ for four days, and a pillared composite with high crystallinity can be obtain...

与原料2H-MoS2相比，柱撑材料的层间距增大，晶粒变小，比表面积增加并且热稳定性提高。对催化苯饱和加氢反应表明，柱撑材料Cr-MoS2的催化活性明显优于未柱撑的2H-MoS2和RaneyNi催化剂，且结晶度较好的柱撑材料更具有较高的催化活性和较好的可重复性。

The dilute hydrochloric acid concentration, Ti/clay ratio, H/Ti ratio, the pillaring reaction temperature, the aging time of pillaring agent and the initial concentration of clay greatly affect the formation of Ti-PILC.

结果表明，盐酸的浓度、Ti／土比、H／Ti比、交联温度、交联剂老化时间和粘土悬浮液浓度等制备条件对钛交联蒙脱石的物化性能有较大的影响。

First, organic pillared montmorillonite were prepared in which three kinds of organic quaternary ammonium salts were used as pillaring agent. Physiochemical properties of organic pillared montmorillonites were characterized by XRD, FT-IR, TG-DTA. Furthermore their characters that have been testified are excellence.

首先用三种有机季胺盐作为柱撑剂制各出有机柱撑蒙脱石，并通过XRD、FT-ZR、TG-DTA等测试手段对其进行了表征，并且对制备的有机柱撑蒙脱石进行了性能测试，证明其性能优良，说明利用干法制备有机柱撑蒙脱石是切实可行的。

Ti-PILCs were also obtained with pillaring agent prepared from Ti(n-C4H9O)4 and HC1 by Sol-Gel, using purified Na-montmorillonite in Hubei as the starting clay.

以鄂东钙基膨润土经提纯钠化后所得的精制钠基蒙脱石d_(001=1.28nm为基质粘土，以钛酸正丁酯[Ti(n-C_4H_9O)_4]为钛源，采用溶胶—凝胶法制备了一系列钛交联蒙脱石纳米复合材料；并对Ti／土比、H／Ti摩尔比和盐酸浓度等主要合成条件进行了讨论。

You can do some assertiveness training.

你可以进行一些自信训练。

We were well on the path to making a rear-wheel-drive global platform," says Mays."

我们正致力于建立一个后轮驱动的平台，"Mays这样说道。"