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661.
G. Bertholon R. Perrin R. Lamartine A. Thozet M. Perrin J. Caillet 《Molecular Crystals and Liquid Crystals》2013,570(1):285-292
It is shown that the charge transfer is negligible in the ground state for organic charge transfer complexes between phenols and quinones. Our objective Is to determine the origin of the stability of the complexes. The geometric, electronic and energetic properties of these complexes were examined by three techniques, crystal structure determination by X-ray diffraction, spectrum and charge transfer calculation by quantum chemical methods, and lattice energy computation. 相似文献
662.
E. F. Sheka V. S. Makarova T. A. Krivenko E. F. Sheka 《Molecular Crystals and Liquid Crystals》2013,570(3-4):251-322
The 1978 Bibliography continues the series of annual issues of Bibliographies Spectroscopy of Molecular Crystals. The full list of these issues from 1957–1968 may be found in Molecular Crystals and Liquid Crystals, 6, 175, 1969. The issues for 1969, 1970, 197 1, 1972, 1973, 1974, 1975, 1976, and 1977 are published ibid, 14, 329 (1971), 17, 55 (1972), 19, 331 (1973), 26, 87 (1974), 30, 239 (1975), 33, 261 (1976), 39, 259 (1977), 46, 25 (1978) and 54, 59 (1979). 相似文献
663.
664.
本文在对FP&S和H&M的创新能力分析框架进行修正的基础上,从创新环境、创新资源、创新成果和创新品牌四个维度建立基于企业层面的区域创新能力分析框架,以此为理论依据建立了基于企业层面的区域创新能力评价指标体系,并引入全局的思想构建全局熵值法模型,在此基础上对京津冀地区、东北地区、长三角地区和南部沿海地区2009~2012年企业层面的创新能力进行了动态评价与分析,研究结果对于认识我国各经济区的企业创新能力提供了重要的参考依据。 相似文献
665.
基于DEA的大学人才培养系统的综合评价 总被引:5,自引:0,他引:5
大学的人才培养系统是国家创新系统的重要组成部分,其投入产出的效果直接关系到创新型国家的建设,因此,对大学人才培养系统有效性进行综合评价十分必要。本文根据相关统计数据,采用DEA方法,对我国教育部直属的72所大学的人才培养综合效率进行了测算,得出如下结论:在2004年的大学规模下,部分大学人才培养系统通常具有较高的总体效率;其余的大学人才培养系统总体效率则较低;而且25所大学规模收益不变,18所大学规模收益递减,29所大学规模收益递增。这为完善大学人才培养体系奠定了基础。 相似文献
666.
A technique based on the repetition of the interference fringe pattern for the automated marking of the PZT phase shifting interference system is described. A closed-loop control is used to circumvent the inherent hysteresis and nonlinear characteristics of PZT. The whole interference system integrated under LabVIEW graphic programming environment provides users a friendly and ease-of-maintenance interface. An application of the algorithm is used to demonstrate the promotion of the Zygo GPI-LC model interferometer to upgrade its phase resolution ability. 相似文献
667.
《Liquid crystals》2012,39(15):2201-2212
ABSTRACTFour compounds from 3FmHPhF homologous series of chiral smectogenic fluorinated compounds (m = 2, 4, 5, 6) were studied by frequency domain dielectric spectroscopy, electro-optic measurements, X-ray diffraction and differential scanning calorimetry. Values of the relaxation time and dielectric increment of relaxation processes versus temperature and bias field were determined. The temperature-dependent tilt angles, spontaneous polarisations, switching times, rotational viscosities, and average intermolecular distances and correlation lengths within smectic layers were obtained. Experimental results were supplemented by density functional theory calculations of isolated 3FmHPhF molecular geometries, and the relationship between the molecular structures and the transverse component of their dipole moments was studied for the mesogens with m = 2, 4, 5, 6, 7. The results are discussed in terms of the length of the CmH2m flexible carbon chain of the homologues. 相似文献
668.
Halogen‐Bond‐Mediated Assembly of a Single‐Component Supramolecular Triangle and an Enantiomeric Pair of Double Helices from 2‐(Iodoethynyl)pyridine Derivatives 下载免费PDF全文
Dr. Chun‐Fai Ng Prof. Hak‐Fun Chow Prof. Thomas C. W. Mak 《Angewandte Chemie (International ed. in English)》2018,57(18):4986-4990
Construction of single‐component supramolecular triangle and unprecedented spontaneous resolution of pairs of intertwined supramolecular 31‐ and 32‐double helices by the self‐assembly of achiral 2‐(iodoethynyl)pyridine and its derivatives have been achieved through intermolecular ethynyl C?I????N halogen bonds in the crystalline state. Fine‐tuning of the molecular structure of the achiral monomer and choice of solvents for crystallization have a dominant effect on the resultant supramolecular architectures. 相似文献
669.
Jing Wang L.W. Guo H.Q. Jia Z.G. Xing Y. Wang J.F. Yan N.S. Yu H. Chen J.M. Zhou 《Journal of Crystal Growth》2006,290(2):398-404
The new developed maskless lateral-epitaxial-overgrowth technique, in which the striped substrates are patterned by wet chemical etching, is systematically investigated using scanning electron microscopy, X-ray diffraction, and atomic force microscopy (AFM). Wing tilt is measured for the GaN films on patterned substrates with a range of “fill factor” (ratio of groove width to stripe period) and for the GaN in different growth time. It is found that changes in these parameters have a significant effect on the extent and distribution of wing tilt in the laterally overgrown regions relative to the GaN directly on the sapphire substrate. Increasing the thickness of GaN films is benefit to reduce wing tilt. The tilt is avoided in the GaN films with 4.5 μm thickness and fill factor for 0.46. The full-width at half-maximum of X-ray rocking curves of the asymmetric diffraction peaks and the image of AFM both show that the threading dislocations in the developed lateral epitaxial overgrowth of GaN films are reduced sharply. The GaN template could be used as an excellent substrate to fabricate high-performance optoelectronic devices. 相似文献
670.
采用格子Boltzmann方法(LBM)和改进的插值格子Boltzmann方法(GILBM)研究了45°斜方腔的顶盖驱动流和Roach通道内的流动特性,并与基准解进行了对比。结果表明,对于45°斜方腔的顶盖驱动流,当雷诺数较小时,两种方法的计算结果与基准解吻合较好;但当雷诺数较大时,采用LBM的计算结果准确性降低,而基于GILBM方法得到的结果准确度升高,且计算稳定性好。对于Roach通道内的流体流动而言,两种方法的计算精度和复杂边界的复杂程度与雷诺数大小有关。根据流场边界形状的复杂程度,网格划分与计算精确度的不同要求,两种方法各有利弊。 相似文献