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991.
Zi‐Yi Yu Han Lai Wen‐Juan Zhao Rui Wu Xue‐Sen Liu Li‐Hua Gan 《International journal of quantum chemistry》2017,117(19)
To elucidate the structure of a compound is a necessary step for its practical applications. To study the structure and properties of metal sulfide fullerene Sc2S@C88 detected by mass spectrometry, 11 194 isomers of C88 and 33 isomers of Sc2S@C88 were systematically examined by density functional theory calculations. The calculations show that the two lowest‐energy isomers are Sc2S@C88:81 738 (IPR‐35) and Sc2S@C88:81 735 (IPR‐32), followed by Sc2S@C88:81 729 (IPR‐26), Sc2S@C88:81 712 (IPR‐9), and Sc2S@C88:81 733 (IPR‐30). Structural analysis shows that the first two energetically favored isomers are bridged by the third and fifth energetically favored isomers, which can transfer into each other via direct Stone–Wales rotation. The calculations of temperature effect show that the first two favored isomers become dominant forms of Sc2S@C88 with decreasing temperature and may coexist in the soot. This structural convertibility among favored isomers of Sc2S@C88 suggest a hidden rule that birds of a feather flock together in metal sulfide fullerenes. This rule may decrease the range of candidate cages for the structural identification of a metal sulfide fullerene. IR spectra are simulated for helping the future experimental identification of Sc2S@C88. 相似文献
992.
We present general analytical expression for two and three-dimensional cases of static energy transfer kinetics in doped nanoparticles (of round, spherical and cylindrical shape). A series of numerical experiments has been performed using Monte-Carlo simulation. The analytical expressions have shown very good coincidence with the computer simulation. 相似文献
993.
A degradable atom transfer radical polymerization inimer: Synthesis,polymerization, and cleavage of the resulting polymer products 下载免费PDF全文
Marios Elladiou Costas S. Patrickios 《Journal of polymer science. Part A, Polymer chemistry》2017,55(17):2831-2839
A novel degradable inimer for atom transfer radical polymerization (ATRP), 2‐(6‐(2‐((2‐bromo‐2‐methylpropanoyl)oxy)ethyl)pyridin‐2‐yl)ethyl methacrylate (PyDEBrMΑ), was synthesized by the two‐step esterification of 2,6‐pyridinediethanol, first with α‐bromoisobutyryl bromide in order to introduce the initiator moiety, and then with methacryloyl chloride in order to introduce the monomer moiety. PyDEBrMA was subsequently used to initiate the self‐condensing ATRP of methyl methacrylate (MMA) to obtain a hyperbranched MMA homopolymer which could be cleaved at the PyDEBrMA residue either by treatment under mildly alkaline hydrolysis conditions (sodium deuteroxide in d6‐DMSO at room temperature) or thermolysis at 150 °C. The lability of the PyDEBrMA residue arises from the presence in its structure of two 2‐(pyridin‐2‐yl)ethyl ester moieties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2831–2839 相似文献
994.
995.
Mohammad M. Khani Zaid M. Abbas Brian C. Benicewicz 《Journal of polymer science. Part A, Polymer chemistry》2017,55(9):1493-1501
The preparation of well‐defined polyisoprene‐grafted silica nanoparticles (PIP‐g‐SiO2 NPs) was investigated. Surface initiated reversible addition fragmentation chain transfer (SI‐RAFT) polymerization was used to polymerize isoprene from the surface of 15 nm silica NPs. A high temperature stable trithiocarbonate RAFT agent was anchored onto the surface of particles with controllable graft densities. The polymerization of isoprene mediated by silica anchored RAFT with different densities were investigated and compared to the polymerization mediated by free RAFT agents. The effects of different temperatures, initiators, and monomer feed ratios on the kinetics of the SI‐RAFT polymerization were also investigated. Using this technique, block copolymers of polyisoprene and polystyrene on the surface of silica particles were also prepared. The well‐defined synthesized PIP‐g‐SiO2 NPs were then mixed with a polyisoprene matrix which showed a good level of dispersion throughout the matrix. These tunable grafted particles have potential applications in the field of rubber nanocomposites. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1493–1501 相似文献
996.
Leonid G. Sokoletsky Olga V. Nikolaeva Leonid P. Bass Victor S. Kuznetsov 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(13):1132-5779
Several numerical and analytical solutions of the radiative transfer equation (RTE) were compared for plane albedo in a problem of solar light reflection by sea water. The study incorporated the simplest case—a semi-infinite one-dimensional plane—parallel absorbing and scattering homogeneous layer illuminated by a monodirectional light beam. Inelastic processes (such as Raman scattering and fluorescence), polarization and air-water surface refraction-reflection effects, were not considered. Algorithms were based on the invariant imbedding method and two different variants of the discrete ordinate method (DOM). Calculations were performed using parameters across all possible ranges (single-scattering albedo ω0 and refracted solar zenith angle θ1), but with a special emphasis on natural waters. All computations were made for two scattering phase functions, which included an almost isotropic Rayleigh phase function and strongly anisotropic double-peaked Fournier-Forand-Mobley phase function. Models were validated using quasi-single-scattering (QSSA) and exponential approximations, which represent the extreme cases of ω0→0 and ω0→1, respectively. All methods yielded relative differences within 1.8% for modeled natural waters. An analysis of plane albedo behavior resulted in the development of a new extended QSSA approximation, which when applied in conjunction with the extended Hapke approximation developed earlier, resulted in a maximum relative error of 2.7%. The study results demonstrated that for practical applications, the estimation of inherent optical properties from observed reflectance can best be achieved using an extended Hapke approximation. 相似文献
997.
998.
Vladan Mlinar 《Annalen der Physik》2015,527(3-4):187-204
In the light of recent developments in computer technology, a promising and efficient way to design a material with a desired property would be to solve the inverse problem: use a physical property to predict structure. Here, we discuss the basic idea and mathematical foundation of the inverse approach, and proposed strategies for its utilization in the design of materials over nano‐ to macro‐scales. At the nano‐scale, analyzed strategies include scanning of a high‐dimensional space of chemical compounds for those compounds that have a targeted property, and identification of correlations in large databases of materials. However, unlike utilization of inverse approach at nano‐scale where full structural information ‐ atoms and their positions‐ is linked to targeted properties, at the meso‐ and macro‐scale, only partial structural information, manifested via structural motifs or representative volume elements, is available. We discuss the role of partial structural information in the inverse approach to the design of materials at those scales. Risks and limitations of the inverse approach are analyzed and dependence of the approach on factors such as structure parametrization, approximations in theoretical models, and feedback from structural characterization, is addressed.
999.
In this paper, we determine the structures of the transfer ideal and its radical ideal for the ring of polynomials F p[x, y] under the action of dihedral group D2 p in the modular case. We mainly use Transfer variety, p order elements, and Hilbert’s Nullstellensatz Theorem. 相似文献
1000.