助手标题  
全文文献 工具书 数字 学术定义 翻译助手 学术趋势 更多
查询帮助
意见反馈
   spin spin coupling 的翻译结果: 查询用时:0.014秒
图标索引 在分类学科中查询
所有学科
物理学
更多类别查询

图标索引 历史查询
 

spin spin coupling
相关语句
  自旋偶合
     The Study of the Nuclear Spin-Spin Coupling Constants between Directly Bonded Atoms by Natural Hybrid Orbitals Ⅱ. ~(13)C-~(13)C Nuclear Spin Spin Coupling Constants ~1/~(13)c-~(13)c
     直接键连原子间的NMR偶合常数的自然杂化轨道研究——Ⅱ.C—C核自旋偶合常数~1J_(~(13)C—~(13)C)
短句来源
     Maximum Overlap Symmetry Molecular Orbital Calculation Under INDO Approximation * Ⅱ Application to Calcutation of the Nuclear Spin Spin Coupling Constants of C H and C C Bonds
     INDO级别下的最大重迭对称性分子轨道Ⅱ.在核自旋偶合常数研究中应用(英文)
短句来源
     THE STUDY OF THE NUCLEAR SPIN SPIN COUPLING CONSTANTS BETWEEN DIRECTLY BONDED ATOMS BY NATURAL HYBRID ORBITALS
     直接键连原子间的NMR偶合常数的自然杂化轨道研究V.~(13)C-~(13)C和~(13)C-~(31)P核自旋偶合常数~1J_(CC)和~1J_(CP)
短句来源
     The generalized relationship which involves the contributions of not only the calculated s character of NHO,but also the net atomic charges,have been applied to obtain relationships for calculation of the nuclear spin spin coupling constants of various 13 C H and 13 C 13 C bonds.
     采用STO 3G基组 ,利用Lowdin正交化原子轨道基组下的密度矩阵 ,得到了分子中各原子的杂化轨道、净电荷与13 C H、13 C 13 C键自旋偶合常数1JCH和1JCC之间关系式。
短句来源
     Based on ab initio HF/6 31G\+* calculations and the subsequent natural bond orbital analysis, a generalized semiempirical relationship has been tested to calculate C H nuclear spin spin coupling constants. It is demonstrated that the generalized relationship satisfactorily reproduces experimental \{\}\+1 J C H values for both cyclic and non cyclic molecules.
     用一种计算直接键链原子核自旋偶合常数1 JA B的统一的半经验关系式 ,研究了各种代表性的环状分子及非环状分子的1 JC H的核自旋偶合常数 ,计算值与实验值吻合的较好 ,说明该统一的半经验关系式既可适用于非环状分子又可适用于环状分子化合物体系的直接键链原子的核自旋偶合常数1 JC H计算
短句来源
  相似匹配句对
     The concept of spin orbit coupling is reviewed.
     本文较系统地但并非全面地讨论粒子的自旋轨道耦合。
短句来源
     A Calculation of the Spin-orbit Coupling Energy
     自旋-轨道耦合能的计算
短句来源
     ON THE ELECTRONIC SPIN
     关于电子自旋两则
短句来源
     biochemical coupling;
     生化偶联 ;
短句来源
     Spin Control
     旋转控制
短句来源
查询“spin spin coupling”译词为用户自定义的双语例句

    我想查看译文中含有:的双语例句
例句
为了更好的帮助您理解掌握查询词或其译词在地道英语中的实际用法,我们为您准备了出自英文原文的大量英语例句,供您参考。
  spin spin coupling
The spin-spin coupling is thus more effective for the syn-periplanar than for the anti-periplanar arrangement of the coupled nuclei.
      
The reason these interactions mimic spin-spin coupling is that they split the = 0 and 1 components in a similar manner as the direct spin-spin terms.
      
The theory of scalar spin-spin coupling constants Magnetic phenomena are included consistently in the Dirac relativistic equation.
      
The spectra are complicated by extensive spin-spin coupling due to the high concentration oflabel.
      
The decrease of the intensity of ESR spectra with increase of vanadia loading in the catalyst samples is attributed to spin-spin coupling.
      
更多          


An improved new method for the synthesis of α, β, β-trifluorostyrene(TFS) was used in the synthesis of six substituted TFS, together with α- and β-trifluoroethenylnaphthal enes. It involves the use of aromatic Grignard reagents with tetrafluoroethylene in THF, as shown in eq. 1(cf. Chinese text for equations, tables and figures). The yield of TFS in THF is the highest among the four solvents tried(i. e. THF, ether, DME and dioxane, Table 1). The structure of all products were establsihed by elemental analysis,...

An improved new method for the synthesis of α, β, β-trifluorostyrene(TFS) was used in the synthesis of six substituted TFS, together with α- and β-trifluoroethenylnaphthal enes. It involves the use of aromatic Grignard reagents with tetrafluoroethylene in THF, as shown in eq. 1(cf. Chinese text for equations, tables and figures). The yield of TFS in THF is the highest among the four solvents tried(i. e. THF, ether, DME and dioxane, Table 1). The structure of all products were establsihed by elemental analysis, IR and ~(19)F NMR, and their yields are listed in Table 2.The UV λ_(max) values of the substituted TFS and styrenes are given in Table 3. The substituent effects on the wave-length shifts of the λ_(max) values are expressed in terms of λ_Y-λ_H values(see Table 3). Obviously, this effect is smaller in the TFS series. The smaller effect is probably caused by the steric interference of the coplanarity of the molecule by the cis-F atom and the phenyl ring.According to the simple model of"distorted π-electron clouds", in compounds of type 3, mutually dependent p-π repulsive effects and the electronic effects of the substituents combine to polarize a double bond. The p-π repulsive forces of F~2 atom and F~3 atom cancell out. If the repulsive force of the substituent Z is smaller than that of the F~1 atom, the π-electron will be pushed to the right(C~1 to C~2), as well as downward from F~1 to F~2. This crude model is useful in the discussion of structure-property relationships of fluoroolefins, e. g., it easily predicts that δ(F~2) be larger than δ(F~1). This model also anticipates that there may be a linear relationship between the substituent parameters of Z and the chemical shift differences of F~1 atom and F~3 atom, △δ_(3-1)(or △δ_(3-2)). To test these ideas, we selected substituted TFS for our study, because with these compounds straight forward comparisons of electronic effects can be made without complications from other factors. The chemical shifts δ(F), spin-spin coupling constants J_(12), and the chemical shift differences △δ of substituted TFS are presented in Table 4. Indeed as expected, four linear relationships were obtained between σ and the following parameters, viz. δ(F~1), δ(F~2), J_(12) and △δ_(3-1)(or △δ_(3-1)).Karplus and Das stated that fluorine chemical shifts were dominated by the second order paramagnetic term and hence by the nature of the fluorine bonding. In Fig. 1 the chemical shifts of F~1 and F~2 move regularly to lower fields in the series p-CH_3O, p-CH_3, m-CH_3, H, p-Cl, m-Cl and m-CF_3, implicating the decrease of electron density of the C~1-F~1 bond and C~1-F~2 bond in the series.As shown in Fig. 3, the J_(12) value decreases with an increase of σ value. This probably can be ascribed to the change of electron density in the region of F~1-C~1-F~2. A reduction of electron density in this region corresponds to a reduction of the availability of electrons which transmits coupling information.A comparison of the π-bond polarity in trifluoroolefins is necessary in the discussion of their properties. We suggest that △δ_(3-1)(or △δ_(3-2)) value be used as a quantitative indicator of the polarity of π-bond in the trifluoroolefin molecule. A higher △δ(3-1) value implies a higher degree of polarization of the π-bond in question.With this criterion the chemical behavior manifested as the yields in the synthesis of TFEN can be rationalized. As shown in Table 5, △δ_(3-1) value of α-TFEN is by 20ppm smaller than that of β-TFEN, the yield of α-TFEN is by 30% larger than that of β-TFEN, whilst the yield of α-TFEN disubstituted product, C_(10)H_7CF:CFC_(10)H_7, is smaller. The rationale is: as indicated by its larger △δ_(3-1) value, the more polarized double bond of β-TFEN is more easily further attacked by another nucleophilic Grignard reagent, thus the monosubstituted product is consumed, in the meantime of course, more of the disubstituted product is formed.The difference of the π-bond polarity between α-TFEN and β-TFEN is probably a consequence of steric factors. In α-TFEN molecule, steric interaction of the F~3 atom and peri-hydrogen atom must have rendered the maintenance of the coplanarity of naphthalene ring and the olefin double-bond difficult, this in turn reduces conjugation of the system and the polarization of the double bond. In short, in the absence of other complicating factors, the larger the △δ_(3-1) value, the more easily is the π-bond attacked by a nucleophilic reagent. Thus by means of arranging a △δ_(3-1) value scale of trifluoroolefins, a quantitative comparision of their reactivity is now possible.

利用各种芳基格氏试剂与四氟乙烯在四氢呋喃中的反应,合成了六个取代三氟苯乙烯,其中取代基分别为:p-CH_3O,p-CH_3,m-CH_3,p-Cl,m-Cl和m-CF_3,还合成了α-与β-三氟萘乙烯. 研究了在已合成的取代三氟苯乙烯化合物(1)中取代基的电子效应对~(19)F NMR参数的影响.建立了取代基的Hammett常数σ分别与下列~(19)F NMR参数间的线性相关关系;化学位移δ(F~1)-δ(F~2)、偶合常数J_12及化学位移之差Δδ_(3-1)=δ(F~3)-δ(F~1)(或者Δδ_(3-2),证实了过去的预计.建议以Δδ_(3-1)值作为衡量三氟乙烯类化合物中π键极化程度的尺度.并把这一定量的“歪电子云”概念与有关的化学事实联系起来.

The chemical shifts and the spin-spin coupling constants of high-resolution NMR spectra of some three-, four-spin cases are caculated by using the trial-and-error method of the Euclidean Norm of Hamiltonian matrix. In this method., the experimental energy levels are used as the zero-order approximation of the Hamiltonian matrix so that the trouble of selecting primary chemical shifts and spin-spin coupling constants is avoided and only one resolution can be obtained

本文应用哈密顿矩阵范数逼近方法,利用计算机计算了三自旋、四自旋系统高分辨核磁共振谱的化学位移和偶合常数。与一般迭代程序相比,简化了计算过程,提高了计算精度,并保证了解的唯一性。选择实验能级值作为哈密顿矩阵零级近似,避免了选取初始δ,J值的麻烦。本方法在图谱定量分析中取得了较好效果。

A New density operator formalism for describing high-spin nuclei systems-angular momentum product operator and Z operator was proposed. The product operator and {Z} operator evolution formulae were derived under the effect of spin-spin couplings and radio frequency pulses. The theory dercription can be used to analyse NMR multi-pulse experiments for high-spin nuclei systems. Re-focused INEPT, DEPT and Homonuclear Cosy for high-spin nuclei systems were calculated by using the...

A New density operator formalism for describing high-spin nuclei systems-angular momentum product operator and Z operator was proposed. The product operator and {Z} operator evolution formulae were derived under the effect of spin-spin couplings and radio frequency pulses. The theory dercription can be used to analyse NMR multi-pulse experiments for high-spin nuclei systems. Re-focused INEPT, DEPT and Homonuclear Cosy for high-spin nuclei systems were calculated by using the new density operator. The Caculation method is discussed.

本文提出了Z算符与角动量积算符相结合的广义积算符,用于描述高自旋弱耦合系统NMR实验谱。给出了高自旋系统在自旋耦合作用下的演变公式,Z算符在脉冲作用下的变化公式。以氘(D)为例,计算了重聚INEPT,DEPT和同核COSY实验谱,并对计算方法作了讨论。

 
<< 更多相关文摘    
图标索引 相关查询

 


 
CNKI小工具
在英文学术搜索中查有关spin spin coupling的内容
在知识搜索中查有关spin spin coupling的内容
在数字搜索中查有关spin spin coupling的内容
在概念知识元中查有关spin spin coupling的内容
在学术趋势中查有关spin spin coupling的内容
 
 

CNKI主页设CNKI翻译助手为主页 | 收藏CNKI翻译助手 | 广告服务 | 英文学术搜索
版权图标  2008 CNKI-中国知网
京ICP证040431号 互联网出版许可证 新出网证(京)字008号
北京市公安局海淀分局 备案号:110 1081725
版权图标 2008中国知网(cnki) 中国学术期刊(光盘版)电子杂志社