共查询到20条相似文献,搜索用时 375 毫秒
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本文采用超声法制备了柚皮素(NAR)与β-环糊精(βCD)的包合物.粉末-X射线衍射(XRD)和红外吸收光谱(IR)测定均表明形成的包合物具有不同于主客体的新的结构性质.1H NMR与ROESY核磁共振(NMR)实验表明NAR以苯环端从βCD的宽口端进入,并形成稳定的超分子包合物.量子化学计算分析NAR/βCD包合物的形成过程表明,驱动力源于焓驱动与氢键弱相互作用力;能隙和结合能分析得到的最优包合模式与NMR研究结果一致;ONIOM分层计算验证了上述结果.分子对接模拟出的最优包合模式也与量子化学计算、NMR的分析结果吻合.本文获取了清晰的NAR/βCD包合物构型及其形成机理,为该超分子药物的定量构效关系研究提供了理论参考. 相似文献
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榄香烯及其衍生物的计算化学研究I β-榄香烯13C NMR化学位移的理论计算 总被引:1,自引:1,他引:0
报道了抗癌新药β-榄香烯的13C NMR化学位移的量子化学计算.在分子力学MMX和量子化学RHF/6-31G*或B3LYP/6-31G*优化结构的基础上进行了两种规范变换方法GIAO和CSGT的Hartree-Fock和B3LYP (6-31G*基组)的化学位移计算.并对计算结果进行了误差分析和线性相关分析.所有的这些结果中,采用GIAO规范变换方法都好于CSGT,而以GIAO-B3LYP/6-31G*//B3LYP/6-31G*计算的结果最好,RMS为4.3ppm,相关系数R2为0.998,SD为2.42 ppm.而GIAO-B3LYP/6-31G*//MMX是一种能兼顾计算时间和计算精度的方法,其RMS、R2和SD分别为4.9、0.996和3.0 4 ppm. 相似文献
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榄香烯及其衍生物的计算化学研究I β-榄香烯13C NMR化学位移的理论计算 总被引:2,自引:2,他引:0
报道了抗癌新药β-榄香烯的13C NMR化学位移的量子化学计算.在分子力学MMX和量子化学RHF/6-31G*或B3LYP/6-31G*优化结构的基础上进行了两种规范变换方法GIAO和CSGT的Hartree-Fock和B3LYP (6-31G*基组)的化学位移计算.并对计算结果进行了误差分析和线性相关分析.所有的这些结果中,采用GIAO规范变换方法都好于CSGT,而以GIAO-B3LYP/6-31G*//B3LYP/6-31G*计算的结果最好,RMS为4.3ppm,相关系数R2为0.998,SD为2.42 ppm.而GIAO-B3LYP/6-31G*//MMX是一种能兼顾计算时间和计算精度的方法,其RMS、R2和SD分别为4.9、0.996和3.0 4 ppm. 相似文献
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Yuki Kurashige 《Molecular physics》2014,112(11):1485-1494
Recent advances in quantum chemical density matrix renormalisation group (DMRG) theory are presented. The DMRG, originally devised as an alternative to the exact diagonalisation in condensed matter physics, has become a powerful quantum chemical method for molecular systems that exhibit a multireference character, e.g., excited states, π-conjugated systems, transition metal complexes, and in particular for large systems by combining it with conventional multireference electron correlation methods. The capability of the current quantum chemical DMRG is demonstrated for an application involving the potential energy curve of the chromium dimer, which is one of the most demanding multireference systems and thus requires the best electronic structure treatment for non-dynamical and dynamical correlation as well as large basis sets. 相似文献
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Abdullah Chandra Sekhar Talari Marcela A. Garcia Martinez Zanyar Movasaghi Shazza Rehman 《应用光谱学评论》2017,52(5):456-506
This article reviews some of the recent advances on FTIR spectroscopy in areas related to natural tissues and cell biology. It is an update on our previously published review on the applications of spectroscopic methods employed for the analysis of biological molecules, and summarizes some of the most widely used peak frequencies and their assignments. The aim of this review is to update and consolidate our previously published spectral database, which will help researchers in defining the chemical structure of the biological tissues introducing most of the important peaks present in the natural tissues more precisely and accurately. In spite of applying different methods, there seems to be a considerable similarity in defining the peaks of identical areas of the FTIR spectra. As a result, it is believed that preparing a unique collection of the frequencies encountered in FTIR spectroscopic studies can provide substantial help for future studies. In this article, we have included recent studies that have been reported since previous publication that will be of considerable assistance and added value to those who are focusing their research on defining chemical pathway to the progression of different diseases. 相似文献
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近年来超导量子计算的研究方兴未艾,随着谷歌宣布首次实现“量子优势”,这一领域的研究受到了人们进一步的广泛关注.超导量子比特是具有量子化能级、量子态叠加和量子态纠缠等典型量子特性的宏观器件,通过电磁脉冲信号控制磁通量、电荷或具有非线性电感和无能量耗散的约瑟夫森结上的位相差,可对量子态进行精确调控,从而实现量子计算和量子信息处理.超导量子比特有着诸多方面的优势,很有希望成为普适量子计算的核心组成部分.以铌或其他硬金属(如钽等)为首层大面积材料制备的超导量子比特及辅助器件(简称铌基器件)拥有其独特的优点以及进一步发展的空间,目前已引起越来越多的兴趣.本文将介绍常见的多种超导量子比特的基本构成和工作原理,进而按照器件加工的一般顺序,从基片选择和预处理、薄膜生长、图形转移、刻蚀和约瑟夫森结的制备等方面详细介绍铌基超导量子比特及其辅助器件的多种制备工艺,为超导量子比特的制备提供一个可借鉴的清晰的工艺过程.最后,介绍若干制备铌基超导量子比特与辅助器件的具体例子,并对器件制备的工艺与方法的优化做展望. 相似文献
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扫描隧道显微镜原子操纵技术是指利用扫描探针在特定材料表面以晶格为步长搬运单个原子或分子的技术.它是纳米尺度量子物理与器件研究领域一种独特而有力的研究手段.利用这种手段,人们能够以原子或分子为单元构筑某些常规生长或微加工方法难以制备的人工量子结构,通过对格点原子、晶格尺寸、对称性、周期性的高度控制,实现对局域电子态、自旋序、以及能带拓扑特性等量子效应的设计与调控.原子操纵技术与超快测量及自动控制技术的结合,使得人们能够进一步研究原子级精准的量子器件,因而该技术成为探索未来器件新机理、新工艺的重要工具.本文首先简介原子操纵方法的发展过程和技术要点,然后分别介绍人工电子晶格、半导体表面人工量子点、磁性人工量子结构、人工结构中的信息存储与逻辑运算、单原子精度原型器件等方面的最新研究进展,以及单原子刻蚀和自动原子操纵等方面的技术进展,最后总结并展望原子操纵技术的应用前景和发展趋势. 相似文献
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Three-dimensional topological insulators are a new class of quantum matter which has interesting connections to nearly all main branches of condensed matter physics. In this article, we briefly review the advances in the field effect control of chemical potential in three-dimensional topological insulators. It is essential to the observation of many exotic quantum phenomena predicted to emerge from the topological insulators and their hybrid structures with other materials. We also describe various methods for probing the surface state transport. Some challenges in experimental study of electron transport in topological insulators will also be briefly discussed. 相似文献
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Alexander Wilce 《International Journal of Theoretical Physics》1990,29(8):805-814
Since its first use, there has been widespread dissatisfaction with the Hilbert-space tensor product as a device for coupling the Hilbert-space models of two separated quantum mechanical systems. The Hilbert-space model is paraphrased manual-theoretically by the assertion that quantum mechanical entities are represented by frame manuals. There is a natural, heuristically straightforward tensor product for (unital) manuals, and it is natural therefore to ask whether the tensor product of frame manuals might serve as an alternative model of separated quantum mechanical systems. It is shown that the states on a tensor product of complex frame manuals give rise uniquely to sesquilinear forms on the tensor product of the underlying Hibert spaces. In certain cases, these in turn give rise to operators, which, however, are not generally positive, and which, even if compact, need not be trace-class. 相似文献
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非对易几何、弦论和圈量子引力理论的发展,使非对易空间受到越来越多的关注.非对易量子理论不同于平常的量子理论,它是弦尺度下的特殊的物理效应,处理非对易量子力学问题需要特殊方法.本文首先介绍了Moyal方程与Wigner函数,利用Moyal-Weyl乘法与Bopp变换将H(x,p)变换成^H(^x,^p),考虑坐标—坐标、动量—动量的非对易性,实现对非对易相空间中星乘本征方程的求解.并利用非对易相空间量子力学的代数关系,讨论了非对易相空间中狄拉克振子的Wigner函数和能级,研究结果发现非对易相空间中狄拉克振子的能级明显依赖于非对易参数. 相似文献
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Gerhard Gerlich 《International Journal of Theoretical Physics》1992,31(7):1103-1129
The first three of these axioms describe quantum theory and classical mechanics as statistical theories from the very beginning. With these, it can be shown in which sense a more general than the conventional measure theoretic probability theory is used in quantum theory. One gets this generalization defining transition probabilities on pairs of events (not sets of pairs) as a fundamental, not derived, concept. A comparison with standard theories of stochastic processes gives a very general formulation of the non existence of quantum theories with hidden variables. The Cartesian product of probability spaces can be given a natural algebraic structure, the structure of an orthocomplemented, orthomodular, quasi-modular, not modular, not distributive lattice, which can be compared with the quantum logic (lattice of all closed subspaces of an infinite dimensional Hubert space). It is shown how our given system of axioms suggests generalized quantum theories, especially Schrödinger equations, for phase space amplitudes. 相似文献