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91.
92.
Atsuomi Shundo Abul K. Mallik Toshihiko Sakurai Makoto Takafuji Shoji Nagaoka Hirotaka Ihara 《Journal of chromatography. A》2009,1216(34):6170-6176
Poly(l-alanine)-grafted porous silica (Sil-Ala22) was prepared by polymerization of N-carboxyanhydride of l-alanine initiated by 3-aminopropylated silica. The retention behaviors of the column packed with Sil-Ala22 were investigated by using alkylbenzenes and polycyclic aromatic hydrocarbons as injection samples in liquid chromatography. The Ala22 phase was in a rigid β-form structure and thus provided specific interaction sites, which were derived from the highly ordered carbonyl and methyl groups. These interaction sites bring unique molecular-shape discriminations: molecular-length and non-planarity selectivity, which are controllable by altering organic solvent used as a part of mobile phase. 相似文献
93.
We present the theoretical investigation of spontaneous magnetization of a coupled 2×2 πring array. It is indicated by free energy calculation that the system has the lowest energy when the four π rings have the full antiparallel configuration. Furthermore, the numerical evaluation results show that the system which favours full antiparallel spontaneous magnetization is a quantum effect deriving from the phase cohering of the superconducting quantum wavefunctions in the four superconducting rings through the shared Josephson junctions. 相似文献
94.
95.
YANGLan-Fei LUXiao-Fu 《理论物理通讯》2002,37(5):589-592
In the GCM we study some properties of π meson as the Goldstone bosons in a nuclear matter with finite density.Using the effective action in a nuclear matter,we calculate the decay constant and π mass as functions of the chemical potential.The relation between the chemical potential and the density of a nuclear matter is firstly given here.We find that fπ and mπ monotonously decrease as nuclear matter density increases.The result is consistent with the usual assumption that the chiral symmetry is gradually restored as the density of a nuclear matter increases. 相似文献
96.
HUANG Fei ZHANG Zong-Ye YU You-Wen 《理论物理通讯》2005,44(4):665-669
The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters are taken to be the values fitted by the energies of the baryon ground states and the kaon-nucleon elastic scattering phase shifts of different partial waves. As a preliminary study the s-channel qq^- annihilation interactions are not included since they only act in the very short range and are subsequently assumed to be unimportant in the low-energy domain. The numerical results are in qualitative agreement with the experimental data. 相似文献
97.
A new metal-organic coordination polymer [Pb(mfpdc)(CH3OH)]n (1, mfpdc=2,6-dimethyl-4-(2-furanyl) pyridine-3,5-dicarboxylate) was synthesized and characterized by single-crystal X-ray analyses. The crystal is orthorhombic, space group Pbca, a=15.6297(18), b=9.4803(11), c=18.598(2), V=2755.8(6)3 , Z=8, Mr=498.44, Dc=2.403 Mg/m3 , F(000)=1872, the final R=0.0275 and wR=0.0726 (I>2 (I)). There are interesting polynuclear zigzag (PbO5 ) n chains in the structure of 1, and there have interesting axially chiral S-and R-unit Pb4L units constructed from prochiral organic ligands through C-H···O bonding. The (R/S)-Pb4L units by sharing Pb centers generate a 2-D coordination network, in which there exist rare π65 ···Pb(3.2610 ) interactions. The solid-state photoluminescent emission of compound 1 appears at 487 nm. 相似文献
98.
《Journal of Coordination Chemistry》2012,65(3-4):415-426
Abstract In this paper the π-acceptor character of an isoelectronic series of ligands is analyzed quantitatively using ab-initio MO calculations and some criteria of MO theory that are widely known among inorganic chemists. The study describes a numerical scale in which the species can be ordered according to their donor/acceptor character and their chemical stability, as well as the possibility of making predictions about the behavior of hypothetical ligands. The results from MO calculations for ionized ligands can easily model the dynamics of the acceptor/donor character during a chemical process. We also emphasize the quickness of the calculations and the simplicity of the theoretical basis behind the analysis. 相似文献
99.
使用PCDTBT作为发光层材料,制备了发光波长为705 nm的红色有机电致发光器件,其结构为ITO/PEDOT:PSS/PCDTBT/BCP/LiF/Al.器件启亮电压为2 V,在9 V时器件达到最高亮度,为29000 cd/m2,最大电流效率为3.5 cd/A.还研究了不同退火温度对器件发光性能的影响.实验结果表明,退火温度为50?C时器件的性能最佳,其原因是此时既有利于溶剂挥发,又保持了分子结构的稳定性,而高温退火降低了PCDTBT的π-π堆积的有序性,从而使得器件性能下降. 相似文献
100.
The crystal structure of cholesteryl 5-[4-(4-n-heptylphenylethynyl)phenoxy]- pentanoate (C53H76O3) was determined by direct methods using single crystal X-ray diffraction data. It crystallises in the triclinic system with space group P1 and Z?=?2. The unit cell parameters are: a?=?10.6791(5), b?=?13.0903(7), c?=?18.6430(9)Å, α?=?94.413(3), β?=?98.222(3), γ?=?112.987(3)°. The final reliability factor was R?=?0.0510 for 7284 observed reflections and the goodness of fit was equal to 1.062. The asymmetric unit cell of the compound was found to contain two symmetry-independent molecules, A and B. In both molecules, the six-membered rings of the cholesterol moiety are conformationally very similar. However, pronounced differences were observed in the conformation of the five-membered ring, which is a half-chair in molecule A and assumes an envelope conformation in molecule B. In both molecules, the phenyl rings are planar. The dihedral angle between the two phenyl rings is 43.4(2) and 42.7(2)° for molecules A and B, respectively. The packing of molecules in the crystalline state was found to be a precursor to the smectic A phase structure. The crystal structure is stabilised by inter-molecular C–H…O and C?H…π interactions. 相似文献