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乙烯自由基
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  ethylene radicals
     A Density Functional Theory(DFT) Study on the Reaction of Ozone with Ethylene Radicals
     乙烯自由基与臭氧反应的DFT计算研究
短句来源
  vinyl radical
     Rotational Analysis of the ~2A″(v′=0)←~2A′(v″=0) Band of the Vinyl Radical
     乙烯自由基~2A″(v′=0)←~2A′(v″=0)带的转动分析
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  “乙烯自由基”译为未确定词的双语例句
     ABSTRACT The mechanism of short chain branching in ethylene high-pressure free-radical polymerization has been studied using density functional theory (DFT) and ab initio methods at B3LYP/6-31G (d) and HF/6-31G(d) levels respectively.
     应用量子化学的密度泛函(DFT)方法和从头算方法分别在B3LYP/6-31G(d)和HF/6-31G(d)水平上对在高压条件下乙烯自由基聚合反应中各短支链的支化反应的反应机理进行了研究。
短句来源
     A THEORETICAL STUDY ON THE INTRAMOLECULAR PROTON TRANSFER OF 2-HYDROXYETHENYL-1-OXYL
     2-羟基-1-氧基乙烯自由基(C_2H_3O_2)的分子内质子转移反应的理论研究(英文)
短句来源
     Study on radical polymerization of VAc initiated by naphthalene lithium complex
     萘锂络合物引发醋酸乙烯自由基聚合的研究
短句来源
     Theoretical Study on the Mechanisms of Reactions of Isocyanic Acid (HNCO) and Isothiocyanic Acid (HNCS) with Ethylene Radical and Halogenated Ethylene Radical
     异氰酸及异硫氰酸与乙烯自由基及其衍生物间反应机理的理论研究
短句来源
     In this section, we study the following three reaction systems:
     2.异氰酸及异硫氰酸与氟代乙烯自由基间的反应;
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  相似匹配句对
     The Macrokinetics of the Free—radical Solution Copolymerization of Vinyl Acetate With Maleic Acid
     醋酸乙烯——马来酸自由基溶液共聚合宏观动力学
短句来源
     A Density Functional Theory(DFT) Study on the Reaction of Ozone with Ethylene Radicals
     乙烯自由基与臭氧反应的DFT计算研究
短句来源
     FREE RADICAL'S SCAVENGING
     自由基的清除
短句来源
     2 radicals.
     2 自由基活性
短句来源
     The Synthesis of Vinylpyridines
     乙烯吡啶的合成
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  vinyl radicals
Experimental evidence on the electronic configuration adopted by vinyl radicals is contrasting.
      
Ab initio study of α- and β- silyl substituent effects on vinyl radicals
      
The geometries of α- and β-silyl substituted vinyl radicals and of α, β-disilylvinyl radical have been optimised with the STO-3G and the STO-3G * basis sets.
      
The stabilisation of vinyl radicals through α-silyl substitution is larger than that due to corresponding alkyl groups.
      
Overall, the silyl substituent effect at vinyl radicals is very different from that computed earlier for the vinyl cations, but qualitatively similar to that found in carbanions.
      
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  vinyl radical
The method is applied to the conformational study of the vinyl radical.
      
Extended Hückel molecular orbital calculations have been performed on the vinyl radical (C2H3·) for a variety of geometries.
      
An initiation mechanism involving the formation of substituted vinyl radical and subsequent oxidation to the corresponding cations is proposed.
      
The presence of an α-silyl group also leads to a tendency towards linearisation of the vinyl radical centre and a corresponding reduction in the inversion barrier.
      
Vinyl radical adds to propylene effectively while hydrogen atom abstraction does not occur.
      
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Vinylidene fluoride has been successfully telomerized with carbon tetrachloride and perfluoro-t-butyl iodide as telogens; various new telomerization products and new compounds derived therefrom have been identified by NMR, IR, elemental analyses and chemical transformations. In agreement with our view that polar factors play an important part in deciding the orientation of free radical additions to vinylidene fluoride, it has been shown that the elcotrophilic radicals·CCl_3 and (CF_3)_3C·add to the methylene...

Vinylidene fluoride has been successfully telomerized with carbon tetrachloride and perfluoro-t-butyl iodide as telogens; various new telomerization products and new compounds derived therefrom have been identified by NMR, IR, elemental analyses and chemical transformations. In agreement with our view that polar factors play an important part in deciding the orientation of free radical additions to vinylidene fluoride, it has been shown that the elcotrophilic radicals·CCl_3 and (CF_3)_3C·add to the methylene end of the alkene.Triethylamine has been used as the dehydrohalogenating agent in the following three reactions: (1) from CCl_3CH_2CF_2Cl (1) to the known compound CCl_12 = CHCF_2Cl (5); (2) from CCl_3CH_2CF_2CH_2CF_2Cl (6) to a mixture of CCl_2=CHCF_2CH_2CF_2Cl (7) and CCl_3 CH_2CF_2CH = CF_2 (8) ; and (3) from (CF_3)_3CCH_2CF_2I (3) to (CF_3)_3CCH = CF_2 (9).The reaction of diethylamine with the iodide 3 and (CF_3)_2CFCH_2CF_2I afforded the amides (CF_3)_3CCH_2CON (C_2H_5)_2 (10) and (CF_3)_2C=CH—CON (C_2H_5)_2 respectively. Dehydroiodination of 3 by KOH followed by hydrolysis yielded the perfluoro-t- butyl substituted acetic acid, (CF_3)_3CCH_2CO_2H(11).The exchange reaction of CCl_3CH_2CF_2Cl (1) with antimony fluorides was found to be able to proceed at relatively low temperature, fielding a mixture of CF_3CH_2CF_2Cl (18) and CF_2ClCH_2CF_2Cl (12). An unrearranged product, CCl_2=CHCF_3 (14) was obtained when the same reaction was applied to the alkene CCl_2 = CHCF_2Cl (5).The telomerization products Cl (CF_2CH_2)_nCCl_3 have been hydrolyzed in the strong acid medium to the corresponding carboxylic acids, Cl (CF_2CH_2)_nCOOH (n = 1~6).The alkaline salts of these acids Cl(CF_2CH_2)_nCOOM (n=3~5) have been proved to be good surfactants for emulsion polymerization of fluoro-olefins.

偏氟乙烯能够分别与四氯化碳和全氟叔丁基碘进行自由基的调聚反应,得到新型的调聚物CCl_3(CH_2CF_2)_nCl(n=1~6)和(CF_3)_3C(CH_2CF_2)_nI(n=1,2)。调聚物的结构由核磁共振谱、红外光谱、元素分析和化学转化所证实。反应中亲电自由基·CCl_3与·C(CF_3)_3主要进攻偏氟乙烯上无氟碳原子,亦即在偏氟乙烯的自由基加成中,极性因素对加成方向起决定性作用。调聚产物CCl_3CH_2CF_2Cl、CCl_3CH_2CF_2CH_2CF_2Cl和(CF_3)_3CCH_2CF_2I用三乙胺脱卤化氢,得到烯烃CCl_2=CHCF_2Cl、CCl_2=CHCF_2CH_2CF_2Cl和(CF_3)_3CCH=CF_2·化合物(CF_3)_3CCH_2CF_2I和(CF_3)_2CFCH_2CF_2I先后用乙二胺和水处理,得到含氟酰胺,(CF_3)_3CCH_2CON(C_2H_5)_2和(CF_3)_2C=CHCON(C_2H_5)_2。(CF_3)_3CCH_2CF_2I先后用氢氧化钾和水处理,得到新的含氟羧酸(CF_3)_3CCH_2COOH,在较低温度下,用氟氯化锑处理CC...

偏氟乙烯能够分别与四氯化碳和全氟叔丁基碘进行自由基的调聚反应,得到新型的调聚物CCl_3(CH_2CF_2)_nCl(n=1~6)和(CF_3)_3C(CH_2CF_2)_nI(n=1,2)。调聚物的结构由核磁共振谱、红外光谱、元素分析和化学转化所证实。反应中亲电自由基·CCl_3与·C(CF_3)_3主要进攻偏氟乙烯上无氟碳原子,亦即在偏氟乙烯的自由基加成中,极性因素对加成方向起决定性作用。调聚产物CCl_3CH_2CF_2Cl、CCl_3CH_2CF_2CH_2CF_2Cl和(CF_3)_3CCH_2CF_2I用三乙胺脱卤化氢,得到烯烃CCl_2=CHCF_2Cl、CCl_2=CHCF_2CH_2CF_2Cl和(CF_3)_3CCH=CF_2·化合物(CF_3)_3CCH_2CF_2I和(CF_3)_2CFCH_2CF_2I先后用乙二胺和水处理,得到含氟酰胺,(CF_3)_3CCH_2CON(C_2H_5)_2和(CF_3)_2C=CHCON(C_2H_5)_2。(CF_3)_3CCH_2CF_2I先后用氢氧化钾和水处理,得到新的含氟羧酸(CF_3)_3CCH_2COOH,在较低温度下,用氟氯化锑处理CCl_2=CHCF_2Cl,只得到氟化产物CCl_2=CH_2CF_3,而没有得到重排产物。调聚物Cl(CF_2CH_2)_nCCl_3(n=1~6)在强酸介质中,能水解成相应的羧酸Cl(CF_2CH_2)_nCOOH,这些酸的碱金属盐Cl(CF_2CH_2)_nCOOM(n=3~5)是良好的表面活性剂,可作为含氟烯烃聚合的乳化剂。

Ab initio quantum chemical method has been used to study the proton transfer of the L-form of 2-hydroxyethenyl-1-oxy(C_2H_3O_2) radical. The geometries of the C_2H_3O_2 radical as well as the transition State of proton transfer have been optimized at the level of UHF/3-21G. Vibrational analysis has been made of tnese two configurations to obtain the vibrational frequencies, by means of which the entropy of activation of the proton transfer reaction of C_2H_3O_2 radical has been evaluated.In order to get better...

Ab initio quantum chemical method has been used to study the proton transfer of the L-form of 2-hydroxyethenyl-1-oxy(C_2H_3O_2) radical. The geometries of the C_2H_3O_2 radical as well as the transition State of proton transfer have been optimized at the level of UHF/3-21G. Vibrational analysis has been made of tnese two configurations to obtain the vibrational frequencies, by means of which the entropy of activation of the proton transfer reaction of C_2H_3O_2 radical has been evaluated.In order to get better energetics, the energies of some points on the Intrinsic Reaction Coordinate (based on the geometries of UHF/3-21G) have been recalculated at the level of UMP2/3-21G~+ (Diffusion function has been added to the H atom participating the transfer). Potential energy profile and tunnel effect correction were obtained by using this sophisticated energy profile. The rate constant of this proton transfer reaction was calculated to be 7.4×10~(11) s(-1).The intramolecular hydrogen bond stabilization energy and Hbond length H(1)O(5) obtained at the optimized geometries of UMP2/3-21G~+ are 19.2 kJ mol~(-1) and 2.057A respectively.

用量子化学从头计算方法研究了2-羟基-1-氧基乙烯自由基的质子转移反应。首先,在UHF/3-21G的水平上,采用能量梯度法优化了反应物和过渡态的几何构型,然后利用这两个优化的构型做了振动分析,找出相应的振动频率和模式,从而得到质子转移反应的活化熵值。此外,又做了内禀反应坐标途径(IRC)。为了求得比较准确的反应势能剖面,以便进行隧道效应校正,用多体微扰法(二级微扰)同时在参加转移的氢原子上附加了扩散函数p(UMP_2/3-21G~+)在IRC的各点上进行能量校正。根据从以上计算结果拟合的抛物线势,求出质子转移的隧道效应校正系数为19.9,然后由过渡状态理论计算了此反应的比速常数为7.4×10~(11)s~(-1)。此外,还得到了该自由基的分子内氢键键能和键长分别为19.2 kJ mol~(-1)和2.057(UMP_2/3-21G~+结果)。

According to the former research,we elaborate in this paper the effect and mechanism which C 2H 4、O ·- i and C 2+ a exert to the flower senescence.We also indicate that the flower senescence is the result which the balance of senescence factors is broken and C 2H 4 likely is the linker among the senescence factors.

本文根据前人关于花衰老的研究,阐述了乙烯、自由基和G2+a对花的衰老的影响及作用机理,指出花的衰老是内部衰老因子相互作用的动态平衡被破坏的结果,乙烯可能是衰老因子之间相互作用的联系者。

 
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