含N、S官能基聚硅烷*

综述了近年来含N、S官能基聚硅烷的研究进展。介绍了吡啶、联吡啶、吡咯等含N官能基与噻吩、硫代官能团等含S官能基取代聚硅烷的制备和光电性能表征,概括了含N,S官能团聚硅烷的分子设计、物理性能与应用领域。最后展望了含N、S官能团聚硅烷研究的发展方向与应用前景。     

Development of density functionals for thermochemical kinetics

A density functional theory exchange-correlation functional for the exploration of reaction mechanisms is proposed. This functional, denoted BMK (Boese-Martin for Kinetics), has an accuracy in the 2 kcal/mol range for transition state barriers but, unlike previous attempts at such a functional, this improved accuracy does not come at the expense of equilibrium properties. This makes it a general-purpose functional whose domain of applicability has been extended to transition states, rather than a specialized functional for kinetics. The improvement in BMK rests on the inclusion of the kinetic energy density together with a large value of the exact exchange mixing coefficient. For this functional, the kinetic energy density appears to correct "back" the excess exact exchange mixing for ground-state properties, possibly simulating variable exchange.     

Thomas–Fermi theory from a perturbative treatment of the hydrogenic limit energy density functional: A possible link to local density functional theory

A perturbation expansion which connects the hydrogenic limit energy density functional to the Thomas–Fermi functional is discussed. This perturbation series, where the Coulomb energy density functional is treated as the perturbation to the hydrogenic limit functional, is, in fact, the q = (N/Z) expansion of Thomas–Fermi theory. A truncated form of the first-order correction to the functional provides further insight into the model which treats the ground state energy as a local functional of the electron density.     

Symbolic algebra in functional derivative potential calculations

This article gives the details of the methodology used in constructing a symbolic algebra program designed for evaluating potentials as the functional derivatives of so-called functional generators in molecular density-functional theory. The derived formulae are used in illustrative examples involving partial functional integration, the comparison of the exchange potential arising from different mathematical representations of the electron density for a given functional generator, and the evaluation and comparison of the potential for different functional generators with a given density. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 300–307, 1998     

功能性鸡蛋

功能性鸡蛋是指除营养和味美外，还具有调节人体生理活动功能的鸡蛋。通过调节微量元素、维生素、不饱和脂肪酸等功能性物质在蛋鸡饲粮中的添加数量及饲喂时间，可获得比正常值高的富集功能性物质和鸡蛋。本文对生产功能性鸡蛋的添加剂、添加技术及其在蛋中的转化率等作了综述。同时也介绍了功能性鸡蛋的食疗效果。     

Adsorption of water in finite length carbon slit pore: comparison between computer simulation and experiment

The effects of surface dimensions and topology on the adsorption of water on a graphite surface at 298 K were investigated using the grand canonical Monte Carlo (GCMC) simulation. Regarding the surface topology, we specifically considered the functional group and its position on the surface. The hydroxyl group (OH) is used as a model for the functional group. For describing the interaction of water, we used the potential model proposed by Muller et al., and the simulated isotherms of water in slit pores are found to depend on the position and concentration of the functional group. The onset of adsorption shifts to lower pressure when the concentration of functional group increases or when the functional group is positioned at the center of the graphene surface. The configuration of a group of functional groups also affects the adsorption isotherm. In all cases investigated, we have found that the hysteresis loop always exists, and the loop size depends on the concentration of the functional group and its position. Finally, we tested the molecular model of water adsorption on a functional graphite pore against the experimental data of a commercial activated carbon. The agreement is found to be satisfactory when the model porous solid is composed of pores having width in the range between 10 and 20 A and functional groups positioned at the center of the graphitic wall.     

An orthogonal approach to multifunctional molecularly imprinted polymers

[structure: see text] An "orthogonal" approach to molecularly imprinted polymers has been demonstrated using a crown ether derived monomer that does not exhibit cross-reactivity with other functional monomers. This strategy provides multiple functional groups in the binding site of molecularly imprinted polymers (MIPs) without unproductive interactions between functional monomers. The orthogonal functional group system was shown to act cooperatively in MIPs to bind a template with higher selectivity than any of the individual functional monomers alone.     

烙印分子刚性对分子烙印手性固定相手性拆分能力的影响

采用丙烯酸胺+2-乙烯基吡啶复合功能单体烙印了刚性较小的苯甲氧羰基-L-丝氨酸、苯甲氧羰基-L-丙氨酸和具有一定刚性的苯甲氧羰基-L-脯氨酸,发现丙烯酸胺+2-乙烯基吡啶体系对于分子刚性较小的分子也具有很好的烙印效果,表明不是烙印分子的刚性而是带有的与功能单体作用的化学功能基团才是实现分子烙印的关键.     

Density functional for spectroscopy: no long-range self-interaction error, good performance for Rydberg and charge-transfer states, and better performance on average than B3LYP for ground states

We present a new density functional called M06-HF. The new functional has full Hartree-Fock exchange, and therefore it eliminates self-exchange interactions at long range. This leads to good performance in TDDFT calculations of both Rydberg and charge-transfer states. In addition, the functional satisfies the uniform electron gas limit, and it is better than the popular B3LYP functional, on average, for ground-electronic-state energetics.     

Communication: a new hybrid exchange correlation functional for band-gap calculations using a short-range Gaussian attenuation (Gaussian-Perdue-Burke-Ernzerhof)

We have developed a new hybrid functional [Gaussian-Perdue-Burke-Ernzerhof (Gau-PBE)] that is suitable for the calculation of solid state bandgaps using a periodic boundary condition. The characteristic of this functional is the use of a Gaussian attenuation scheme (Gau) to include a short-range Hartree-Fock (HF) exchange. This new functional can perform barrier height calculations with an accuracy comparable to the middle-range hybrid functional and bandgap calculations with an accuracy comparable to the Heyd-Scuseria-Ernzerhof (HSE) functional. However, the point is that the performance can be achieved using a Gaussian HF exchange, while the HISS functional calculates twice HF-exchange integrations using an error function to obtain both performances. In addition, Gau-PBE functional can decrease the time cost of bandgap calculations by an average of 40% compared to the HSE functional.     

生物特异性功能高分子

模仿天然生物活性高分子关键作用点的化学组成，在高分子链上接上各种官能团或化学残基，制备具有与该天然高分子相似生物活性的高分子，即生物特异性功能高分子。本文主要介绍拟肝素高分子和似粘连 蛋白高分子两种生物特异性功能高分子。     

含硅功能化聚烯烃:合成及应用

聚烯烃功能化改性是获得高性价比新材料的有效途径。含硅功能化聚烯烃(SFPO)是聚烯烃分子结构中含有机硅功能基团或有机硅聚合物链段的一类功能化聚烯烃的统称。由于有机硅功能基团及有机硅聚合物特殊的理化性质,SFPO通常具有丰富反应性或优异性能,成为一类有代表性的功能化聚烯烃。SFPO可以作为反应性中间体,用于制备具有复杂拓扑结构的功能化聚烯烃(如星型聚合物、梳型聚合物、接枝共聚物)或聚烯烃共价键接枝改性纳米材料;SFPO还可作为功能性添加剂(如增容剂、加工助剂,表面改性剂),用于开发聚烯烃新材料。近年来,研究人员在含硅功能化聚烯烃研究领域取得了系列进展,本文旨在对相关工作进行系统总结,以期引起同行注意并促进相关研究深入发展。     

STUDY ON THE NON-COVALENT INTERACTION OF APIGENIN MOLECULARLY IMPRINTED POLYMERS BY SPECTROMETRY

The non-covalent interaction between aPigenin （API） and different functional monomers （α-methylacrylic acid （MAA）, acrylamide （AM）, 2-vinylpyridine （2-Vpy） and combined functional monomers （AM/2-Vpy）） was determined by UV spectrometry, and a series of apigenin molecularly imprinted polymers （API-MIPs） was synthesized with different functional monomers through molecular imprinting technology. The relationship between the non-covalent interaction of template/functional monomer and absorption of MIPs also was studied. The results showed that the order of the strength of the non-covalent interaction between API and different functional monomers in tetrahydrofuran （THF） is as follows： 2-Vpy〉 AM/2-Vpy〉AM〉MAA, which is positive correlation to the absorption capability of corresponding MIPs, and 2-Vpy is the optimum functional monomer among the used monomer for preparing API- MIPs.     

Current-dependent extension of the Perdew-Burke-Ernzerhof exchange-correlation functional

The probability current density is used in addition to the electron density and its gradient as a variable in the construction of an exchange-correlation functional. Starting from the Perdew-Burke-Ernzerhof generalized gradient approximation, we employ exact conditions to build a nonempirical exchange functional. Matching the correlation functional to that for exchange yields a current-dependent approximation for correlation. The resulting functional is given in a simple closed form. Application of this approximation to open shell atoms eliminates the artificial level splitting of formally degenerate states observed with generalized gradient approximations.     

Levy Constrained Search in Fock Space: An Alternative Approach to Noninteger Electron NumberSCI北大核心CSCD

By extending the Levy wavefunction constrained search to Fock Space,one can define a wavefunction constrained search for electron densities in systems having noninteger number of electrons.For pure-state v-representable densities,the results are equivalent to what one would obtain with the zero-temperature grand canonical ensemble.In other cases,the wavefunction constrained search in Fock space presents an upper bound to the grand canonical ensemble functional.One advantage of the Fock-space wavefunction constrained search functional over the zero-temperature grand-canonical ensemble constrained search functional is that certain specific excited states(i.e.,those that are not ground-statev-representable) are the stationary points of the Fock-space functional.However,a potential disadvantage of the Fock-space constrained search functional is that it is not convex.     

A universal bridge functional for infinitely diluted solutions: A case study for Lennard-Jones spheres of different diameters

We propose a universal bridge functional for closure of the Ornstein-Zernike (OZ) equation for infinitely diluted solutions of Lennard-Jones spheres of different sizes in a Lennard-Jones fluid. The bridge functional is parameterized using data from molecular dynamics (MD) simulations. We show that for all of the investigated systems, the bridge functional can be efficiently parameterized with an exponential function that depends only on the ratio of the sizes of solute and solvent atoms. To check the parameterization, we solve the OZ equation with a closure that includes the parametrized functional, and with a closure without the bridge functional (a hypernetted chain closure). We show that introducing the bridge functional allows us to obtain radial distribution functions (RDFs) close to the MD results, and to improve substantially predictions of the location and height of the first peak of an RDF.     

Benchmarking the performance of time-dependent density functional methods

The performance of 24 density functionals, including 14 meta-generalized gradient approximation (mGGA) functionals, is assessed for the calculation of vertical excitation energies against an experimental benchmark set comprising 14 small- to medium-sized compounds with 101 total excited states. The experimental benchmark set consists of singlet, triplet, valence, and Rydberg excited states. The global-hybrid (GH) version of the Perdew-Burke-Ernzerhoff GGA density functional (PBE0) is found to offer the best overall performance with a mean absolute error (MAE) of 0.28 eV. The GH-mGGA Minnesota 2006 density functional with 54% Hartree-Fock exchange (M06-2X) gives a lower MAE of 0.26 eV, but this functional encounters some convergence problems in the ground state. The local density approximation functional consisting of the Slater exchange and Volk-Wilk-Nusair correlation functional (SVWN) outperformed all non-GH GGAs tested. The best pure density functional performance is obtained with the local version of the Minnesota 2006 mGGA density functional (M06-L) with an MAE of 0.41 eV.     

Benchmark calculations for reduced density-matrix functional theory

Reduced density-matrix functional theory (RDMFT) is a promising alternative approach to the problem of electron correlation. Like standard density functional theory, it contains an unknown exchange-correlation functional, for which several approximations have been proposed in the last years. In this article, we benchmark some of these functionals in an extended set of molecules with respect to total and atomization energies. Our results show that the most recent RDMFT functionals give very satisfactory results compared to standard quantum chemistry and density functional approaches.     

A self-contained and portable density functional theory library for use in Ab Initio quantum chemistry programs

A major unresolved problem of density functional theory is the yet unknown exchange-correlation functional, which leads to a proliferation of its less or more successful approximations. A practical implementation of these numerous functionals can present a substantial challenge particularly if the higher order functional derivatives are required. We present a systematic method of functional implementation. The method allows a clean handling of a large number of functionals in a mutually independent way. We developed an extensive set of automatic test routines to facilitate functional and derivative testing with respect to the implementation correctness and numerical stability. An integral part of the presented solution is a program for automatic code generation from analytical formulas that uses only freely available tools. Code for evaluation of functionals and their first, second, third, and fourth derivatives can be generated, which accelerates the development, implementation, and testing of new functionals.     

Method of local-scaling transformations and density functional theory in quantum chemistry. III. The energy density functional: Spin-restricted approach

The rigorous derivation of the energy density functional is proposed within the framework of the spinfree, or spin-restricted formulation of the energy density functional theory. It is shown particularly that the kinetic energy density functional is given by a sum of the Weizsacker term and the so-called “modified” Thomas–Fermi one. The variational principle is formulated for the energy density functional theory in terms of the Euler–Lagrange equation, and the virial theorem is proposed.