查询词典 conformer

Molecular conformation calculations were made for two possible conformers(eclipsed and staggered with respect to the methyl group)of the compound Calculated results show that:the stable conformer of pyruvic acid is the eclipsed one;The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the normal vibrational modes.

结果表明：在丙酮酸分子的两种构象中，重叠式比较稳定*B3LYP计算得到的构型参数与实验结果比较一致；在振动频率的计算中，BLYP未标度力场所计算的非CH3伸缩振动基频预测值和实验值的平均绝对偏差为10.4cm-1；而HF标度力场的平均绝对偏差为17.9cm-1。

Many-body analysis was also carried out to obtain relaxation energy and many-body interaction energy (two, three, and four-body), and the most stable conformer has the basis set superposition error corrected interaction energy of －102.61 kJ/mol.

多体相互作用分析表明，最稳定的氢键结构经基组重叠误差校正后总相互作用能为-102.61 kJ/mol，驰豫能，两体与三体相互作用能对总相互作用能的贡献较大，四体相互作用能对总相互作用能有很小的贡献。

In this dissertation, systematic and extensive conformational search has been performed for asparagine and aspartic acid in gas phase and solution and the properties of the stable conformers are studied using DFT based first-principles calculation. The concerned properties include geometry structure, IR spectra, conformer distributions, intramolecular interactions, ionization energies and electron affinities, protonation and deprotonation processes.

在本论文中，我们对天冬酰胺和天冬氨酸在气相和溶液中的稳定构型进行了系统而全面的寻找，并研究了其稳定构型的几何结构、红外光谱、构型分布、分子内相互作用、电离能、电子亲合能、质子化和去质子化过程等相关性质。

In chapter 4,taking the CCSD results as references,the performances of five DFT(BHandHLYP,MPWB1K,B3LYP,B3PW91 and SVWN) and two WFT(HF and MP2) methods for describing relative conformer energies,vertical electron detachment energies,deprotonation energies,and proton affinities of 22 amino acids were determined.

第4章中以高精度的耦合簇方法的计算结果为基准，测试了五种密度泛函方法(BHandHLYP，MPWB1K，B3LYP，B3PW91和SVWN)和两种波函方法(HF和MP2)对描述22种氨基酸体系的构型相对能量，垂直电离能，质子化和去质子化能这四种能量性质的能力。

Structures of Na~+-AD ion-complexes with 1 or 2 H2O molecules were obtained. It was found that H2O can bond with Na~+ in the structure of Na~+-AD to form Na-O van der Waals bond. H2O molecule can also bond with N or O atoms in AD moiety to form H-bonds as N-H…Ow or O…Hw-Ow. The former process takes place more easily. The most stable structures of Na~+-AD ion-complexes with 1 and 2 H2O molecules are W-C7AB and 2W-C7AB, respectively.αB conformer of Na~+-AD can not exist in the presence of 2 H2O molecules.

研究发现水分子可以结合在Na~+-AD络合离子中的Na~+附近形成Na-OW范德华键，也可以与Na~+-AD络合离子骨架结构中电负性较强的N或O原子结合形成N-H…OW或O…HW-OW氢键，相对而言，水分子更容易结合在Na~+-AD络合离子中的Na~+位置，Na~+-AD最稳定的带1个或2个水分子的结构分别为W-C7AB和2W-C7AB，Na~+-AD络合离子的αB构象在2分子水存在的情况下完全消失。

1H NMR spectroscopic analysis of aromatic protons combined with theoretical analysis of molecular structures proved the existence of two rotational isomers at 300 K, as well as a rapid interconversion equilibrium at 330 K for both compounds Ⅰ and Ⅱ. However, only one conformer exists for compound Ⅲ and puerarin containing 7-phenolic hydroxyl instead of propyl in A-ring as the case of compounds Ⅰ and Ⅱ. Based on UV-Visible absorption data of neutral and basic solutions, and on the density function calculations, the 7-phenolic hydroxyl group in A-ring was found to be more acidic than the 4'-phenolic hydroxyl group in B-ring. The mechanism of derivation reaction and the structure-reactivity relationship of puerarin as an antioxidant were further discussed.

其中7-丙基葛根素Ⅱ属于新型取代衍生物；变温1H NMR和理论计算结果表明，在300 K时，葛根素和4'-丙基葛根素以单一构型存在；而7，4'-二丙基葛根素和7-丙基葛根素则存在两种核磁可分辨的旋转异构体，当温度升至330 K时，两种异构体可以相互转化；通过对比分析葛根素及其衍生物脱质子产物的紫外可见吸收光谱并结合理论计算，确定了A环上7位酚羟基比B环上4'位酚羟基先脱去质子，并由此进一步阐明了葛根素衍生化反应机理以及在抗氧化作用中可能的活性位点和结构活性关系。

In mitosis, a Mad1-Mad2 core complex recruits cytosolic Mad2 to kinetochores through Mad2 dimerization and converts Mad2 to a conformer amenable to Cdc20 binding, thereby facilitating checkpoint activation.

在减数分裂中，Mad1-Mad2核心复合物通过Mad2二聚化募集胞质Mad2至动粒，并转变Mad2成为能被Cdc20结合的形态，因此促进检验点的活化。

The total inter-action energy of the most stable conformer has the basis set superposition error corrected total interaction energy 99.53 kJ/mol, and many-body analysis shows that two-and three-body energies have significant contribution to the total interaction energy whereas the relaxation energies and four-body energies are small.

对8个稳定氢键结构进行多体相互作用分析表明，最稳定的氢键结构经基组重叠误差校正后总相互作用能为－99.53kJ/mol，两体与三体相互作用能对总相互作用能的贡献较大，驰豫能与四体相互作用能对总相互作用能有很小的贡献。

The influences of the inclusion of Na~+ into each conformer (C7AB, C7"AB, C7eqB, C5A, C7axB orα"B) of AD molecule on the Ramachandran angles of molecular backbone and the hydrogen bonds in AD moiety were discussed in detail. It was found that in the forming process of bidentate structures of Na~+-AD ion-complexes, the original H-bonds in AD molecule were fully broken down, accompanying with the new formation of the two Na-O bonds.

论文中详细探讨了Na~+-AD络合离子六种构象的空间构型，分析了丙氨酸二肽与Na~+作用过程中AD分子骨架Ramachandran角及分子内N(1)–H(1)…O(2)、N(2)–H(2)…O(1)、N(1)–H(1)…N(2)和N(2)–H(2)…N(1)氢键的变化，研究发现Na~+与AD分子形成双齿结构时，AD骨架中原先的氢键全部被破坏，继而形成了两个新的Na-O键；Na~+与AD分子形成单齿络合离子时，AD骨架中原先的氢键或者得到增强或者断裂之后出现新的强度更大的氢键。

We thorough search the stable conformers of aromatic amino acids and arginine and examine the properties of the stable conformers using ab initio and DFT methods. The properties examined include the characteristics of intramolecular interactions, IR and UV spectra, temperature dependent conformer distributions, electron attachment and ionization energies, protonation/deprotonation processes.

木论文对芳香型氨基酸和精氨酸进行了理论研究，研究的性质包括几何结构、电子结构、构刑分布、电离能和电子亲和势、质子化过程、红外谱、紫外谱以及分子内相互作用等方面。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。