Set Packing问题起源于分割问题的应用,是在强约束条件对元素进行划分。在复杂性理论中,此问题是一类重要的NP难问题,被广泛应用于调度、代码优化和生物信息学等领域。特别是在参数计算理论产生后。此问题再次成为研究的热点问题。依据...Set Packing问题起源于分割问题的应用,是在强约束条件对元素进行划分。在复杂性理论中,此问题是一类重要的NP难问题,被广泛应用于调度、代码优化和生物信息学等领域。特别是在参数计算理论产生后。此问题再次成为研究的热点问题。依据所研究问题的差异,本文将Set Packing问题分成5类,并给出了具体的定义。在此基础上,分别介绍了求解这5类问题的相关算法,着重分析和比较了参数算法中所运用的各项技术,并提出了该问题算法研究的一些发展方向。展开更多
Rodin and Sullivan （1987） proved Thurston＇s conjecture that a scheme based on the Circle Packing Theorem converges to the Riemann mapping, thereby proved a refreshing geometric view of the Riemann Mapping Theorem. ...Rodin and Sullivan （1987） proved Thurston＇s conjecture that a scheme based on the Circle Packing Theorem converges to the Riemann mapping, thereby proved a refreshing geometric view of the Riemann Mapping Theorem. Naturally, we consider to use the ellipses to pack the bounded simply connected domain and obtain similarly a sequence simplicial homeomorphism between the ellipse packing and the circle packing. In this paper, we prove that these simplicial homeomorphism approximate a quasiconformal mapping from the bounded simply connected domain onto the unit disk with the modulus of their complex dilatations tending to 1 almost everywhere in the domain when the ratio of the longer axis and shorter axis of the ellipse tending to ∞.展开更多
A new mononuclear Cu（Ⅱ） dithiocarbamate complex CuI（prdtc）（phen） 1 （prdtc = N-pyrrolidinyldithiocarbamate, phen = 1,10-phenanthroline） was synthesized and characterized by elemental analysis, IR spectrum, and...A new mononuclear Cu（Ⅱ） dithiocarbamate complex CuI（prdtc）（phen） 1 （prdtc = N-pyrrolidinyldithiocarbamate, phen = 1,10-phenanthroline） was synthesized and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 8.7110（9）, b = 14.7143（14）, c = 14.8507（15） A, β = 109.721（6）°, V = 1791.9（3） A3, Z = 4, Dc = 1.916 g/cm3, CI7H16CulN3S2, Mr = 516.89, λ（MoKa） = 0.71073A,μ = 3.178 mm^-1, F（000） = 1012, the final R = 0.0369 and wR = 0.0987. A total of 4082 unique reflections were collected, of which 2916 with I 〉 2σ（I） were observed. The Cu（Ⅱ） atom is five-coordinated in a distorted square-pyramidal geometry by one I atom in the apical position, two S atoms from a prdtc ligand and two N atoms from a phen ligand in the basal plane. There exist face-to-face aromatic π-π stacking interactions between adjacent phen ligands stabilizing the structure and making the complex assemble into a 1D structure along the a axis. It can be concluded that the difference of the dtc flexibility and reaction conditions result in the structural difference between complex 1 and CuI（dmdtc）（phen） （dmdtc = N, N-dimethyldithiocarbamate）.展开更多
基金supported by the National Natural Science Foundation of China(10701084)Chongqing Natural Science Foundation (2008BB0151)
文摘Rodin and Sullivan （1987） proved Thurston＇s conjecture that a scheme based on the Circle Packing Theorem converges to the Riemann mapping, thereby proved a refreshing geometric view of the Riemann Mapping Theorem. Naturally, we consider to use the ellipses to pack the bounded simply connected domain and obtain similarly a sequence simplicial homeomorphism between the ellipse packing and the circle packing. In this paper, we prove that these simplicial homeomorphism approximate a quasiconformal mapping from the bounded simply connected domain onto the unit disk with the modulus of their complex dilatations tending to 1 almost everywhere in the domain when the ratio of the longer axis and shorter axis of the ellipse tending to ∞.
基金supported by the National Natural Science Foundation of China (Nos. 50572030 and 50372022)the Research Fund of Huaqiao University (No. 06BS216)the Young Talent Program of Fujian Province (No. 2007F3060)
文摘A new mononuclear Cu（Ⅱ） dithiocarbamate complex CuI（prdtc）（phen） 1 （prdtc = N-pyrrolidinyldithiocarbamate, phen = 1,10-phenanthroline） was synthesized and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 8.7110（9）, b = 14.7143（14）, c = 14.8507（15） A, β = 109.721（6）°, V = 1791.9（3） A3, Z = 4, Dc = 1.916 g/cm3, CI7H16CulN3S2, Mr = 516.89, λ（MoKa） = 0.71073A,μ = 3.178 mm^-1, F（000） = 1012, the final R = 0.0369 and wR = 0.0987. A total of 4082 unique reflections were collected, of which 2916 with I 〉 2σ（I） were observed. The Cu（Ⅱ） atom is five-coordinated in a distorted square-pyramidal geometry by one I atom in the apical position, two S atoms from a prdtc ligand and two N atoms from a phen ligand in the basal plane. There exist face-to-face aromatic π-π stacking interactions between adjacent phen ligands stabilizing the structure and making the complex assemble into a 1D structure along the a axis. It can be concluded that the difference of the dtc flexibility and reaction conditions result in the structural difference between complex 1 and CuI（dmdtc）（phen） （dmdtc = N, N-dimethyldithiocarbamate）.
