查询词典 bond energy

Density functional theory calculations have been carried on the molecular knot at the RB3LYP/6-31G levels. Based on the optimized geometry, the vibrational spectra, natural bond orbital and orbital energy level analysis for C30 carbyne trefoil knot have been calculated at the same level, and compared with the cyclo-C30 carbyne molecule.

本文用密度泛函方法[DFT/RB3LYP/6-31G]对分子结构和光谱性质进行了研究，在优化构型的基础上通过自然键轨道方法和轨道能级研究了它的共轭性、成键情况和稳定性，并与平面型C30卡宾环分子进行了比较。

In this thesis,the AM1,MNDO,MINDO/3(mainly AM1)and INDO/S-CI semiempirical MO methods were used toinvestigate the excited-state intramolecular protontransfer reactions of salicylic acid derivatives—salicylic acid,methyl salicylate,salicylaldehyde,o-hydroxyaceto-phenone,salicylamide and 3-hydroxy-picolinamide (6 conformers and 2-3 anion species);2-(2'-hydroxy-5' methylphenyl) benzotriazole(4 conformers),2-(2' hydroxyphenyl) benzimidazole (3 conformers and 3anion species),Bis-2,5-(2-benzoxazolyl)hydroquinone(3 conformers),2-(2'-hydroxyphenyl)benzothiazole(2conformers) and 7-azaindole dimer (2 conformers).Theinvestigations were described as follows.Geometry optimization,relative stability andhydrogen bonding energy First,for sylicylic acid derivative molecules,the AM1,MNDO and MINDO/3 methods were used toinvestigate ground-state geometry optimization,energies,relative stabilities and hydrogen-bondingenergies on the five kinds of the molecules(designing 6 conformers and 2-3 anion species).Comparing with experimental data,the optimizedgeometry,the order of stability,the hydrogen-bonding energies and the distances between O-O in O-H..O hydrogen bonds by AM1 method were in agreementwith the experimental data,however,the C-C bondlengths optimized by MNDO and MINDO/3 were longer,C-O and O-H bond lengths were shorter;for C-N bondlengths,the results opitimized by MNDO method werethe same as those by AM1 method,nevertheless the C-Nbond lengths given by MINDO/3 method were muchshorter.For some sylicylic acid derivatives(e.g.methyl salicylate,salicylamide),the order ofstabilities on the conformers given by MNDO andMINDO/3 methods were not in agreement with theexisting conformers deduced by experimental methods,and the hydrogen bonding energies calculated by MNDO.and MINDO/3 methods were smaller.Second,the studyon the other systems found that the optimizedgeometry of the proton-transfered product with INDOmethod could not be obtained,only could theoptimized geometry of reactant be obtained,and thecalculated hydrogen bonding energies were greater.Many results of calculation indicated that the studyon the excited-state intramolecular proton transferreaction system using AM1 method was suitable andreliable.

本论文用AM1、MNDO、MINDO/3（主要是AM1）和INDO/S-CI半经验分子轨道方法对水杨酸衍生物系列——水杨酸、水杨酸甲酯、水杨醛、O-羟基乙酰苯酮、水杨酰胺和3-羟基吡啶酰胺（6种异构体和2-3种阴离子）；2-（2'-羟基-5'-甲基苯基）苯并三〓唑（4种异构体）；2-（2'-羟基苯基）苯并咪唑（3种异构体和3种阴离子）；2，5-二间氮杂氧茚氢醌（3种异构体）；2-（2'-羟基苯基）间〓杂硫茚（2种异构体）和7-〓吲哚二体（2种异构体）的激发态分子内质子转移反应在以下几个方面进行了较系统的理论研究：几何构型优化和相对稳定性及氢键能首先以水杨酸衍生物系列分子为例，用AM1、MNDO和MINDO/3方法考察了5种分子（每种分子设计6种异构体和2-3种阴离子）的基态几何构型优化，能量、相对稳定性和氢键能计算，通过和实验数据进行比较，AM1方法给出的优化几何构型、稳定性次序、氢键能和O—H。。。O氢键的0—0距离与实验数据吻合最好，MNDO和MINDO/3方法优化的C-C键长偏长，C-O键和O-H键长偏短；对于C-N键长，MNDO和AM1优化结果差别不大，而MINDO/3给出了过短的C-N键长，MNDO和MINDO/3方法给出的有些水杨酸衍生物分子（如水杨酸甲酯和水杨酰胺）异构体的稳定性次序和实验上推测的可存在异构体结果不一致，MNDO和MINDO/3方法给出的氢键能偏低，对其他体系的研究发现INDO方法常常不能得到质子转移产物的优化几何构型，只能得到反应物的优化构型，并且估算的氢键能偏高，大量的计算结果表明AM1方法对本论文研究的激发态分子内质子转移反应体系是适宜和可靠的。

Next HOMO or HOMO-1 for the radical cations calculated by the ab initio 3-21+G^* method, and the atom-pair interaction energy determined by NMDO calculation, it is shown that when n is equal to or largey than 3 in the bridge chain (CH2)n for bicyclo diamine radical cations, the bridgehead nitrogen atoms form a weak N, N'-three-electron σ-bond through space.

通过比较这些阳离子几何构型，HOMO和NHOMO(即NextHOMO和HOMO-1)，和由MNDO计算确定的原子对作用能，表明当二氮双环游离基阳离子的桥链(CH2)n的n≥3时，桥头氮原子通过空间相互用用形成了一个弱的N，N'-三电子σ键。

Au nanoparticles which were prepared by sodium citrate reduction of chloroauric acids were taken as the energy acceptors. Au nanoparticles were linked to 3'-SH—DNA by Au—S bond.

采用柠檬酸钠还原氯金酸法制取的Au纳米粒子作为能量受体，通过Au—S键将单链DNA连接到表面。

At the same time, the K, G, Vp, and Vs of forsterite decreased too because of density decrease 3.0% caused by H atoms replacing Mg atoms in the crystal. Water also increases the total energy of the forsterite system, i. e. the crystal stability and the power of bond were reduced at high pressure and temperature.

在常温常压下，2个氢原子置换1个镁原子会使镁橄榄石的密度降低3.0%，是波速及弹性模量减小的原因，同时使镁橄榄石体系的基态总能增加，降低矿物的稳定性和键之间的强度。

Endo\|1,4\|β\|xylanases(E.C.3.2.1.8),hydrolyzing specifically β\|1,4 glucosidic bond of xylan,have wide commercial applications in industrial processes,such as pulp and paper,foodstuff,textile,feedstuff and energy.

木聚糖酶专一性水解木聚糖分子中β 1 4 糖苷键，在制浆造纸、食品、纺织、饲料、能源工业中具有广阔的应用前景。

Foreign atoms were placed over the sheet at several symmetrical positions, namely, over a carbon atom, over a C-C bond, over the center of a pentagonal, hexagonal, and heptagonal ring. The following conclusions have been drawn: The cohesive energy of adsorbate and perfect sheet at all three adsorption sites is always lower than that on a sheet with a Stone-Wales defect embedded at all five sites.

得到的主要结论如下：所有外来原子在含有Stone-Wales缺陷的石墨烯片上不同位置上吸附的结合能都大于在其在完整石墨烯片上不同位置上的结合能，因此在碳管中引入Stone-Wales缺陷能够提高原子在碳管上的吸附能力，同时提供了很多稳定的吸附位置。

Whereas, at the second stage H-transfer from indole to malonate occurs with the formation of the new C—H bond, the energy barriers calculated for this step are 99.2 and 115.1 kJ/mol for the R - and S -configuration product, respectively.

其中第一阶段由复合物经过渡态TS1生成中间体IM，是C—C键的形成阶段，该阶段的活化能垒较后一阶段要大，是该反应的决速步骤；第二阶段由IM经过渡态TS2生成产物，完成H迁移和C—H键的形成。

The EE of metallics of Ti—Al system is studied in riew of bond structures and cleave energy, then the natural means and practical technology to improve EE are proposed.

也从键结构及解理能对Ti—Al系金属间化合物的环境脆性进行了探讨，提出了解决EE的根本途径及实际工艺。

CMTC crystal belongs to metallorganic complex compounds and growth units are in the form of complex anions. Therefore, there are probably some unsaturated electrovalent bonds on the growth face, which undergoes a "restruction" process by bond linkages until a stable state with least surface energy is reached.

2CMTC晶体是配合物型晶体，以配位阴离子基团形式向生长界面堆积生长，因此在界面上很可能会存在着一些不饱和的离子悬键，悬键之间可能相互连接进行&重构&以达到表面自由能最小的稳定状态。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。