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** Email: wei.97{at}osu.edu*** Email: murray.308{at}osu.edu**** Email: xiao.37{at}osu.edu The Voronoi diagram heuristic has been proposed for solvingthe p-centre problem in continuous space. However, importantassumptions underlie this heuristic and may be problematic forpractical applications. These simplifying assumptions includeuniformly distributed demand, representing a region as a rectangle;analysis of a simple Voronoi polygon in solving associated one-centreproblems and no restrictions on potential facility locations.In this paper, we explore the complexity of solving the continuousspace p-centre problem in location planning. Considering theissue of solution space feasibility, we present a spatiallyrestricted version of this problem and propose methods for solvingit heuristically. Theoretical and empirical results are provided. 相似文献
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Yu Zhang Hongping He Yingtong Di Shuzhen Mu Yuehu Wang Junsong Wang Chunshun Li Ningchuan Kong Suo Gao Xiaojiang Hao 《Tetrahedron letters》2007,48(52):9104-9107
Two new Daphniphyllum alkaloids with daphnicyclidin-type skeleton, paxiphyllines A (1) and B (2) were isolated from the twigs and the leaves of Daphniphyllum paxianum. Paxiphylline A (1) has an unprecedented additional carbon from a biogenetic perspective. The structures and relative configurations were elucidated on the basis of spectroscopic data. 相似文献
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亮黄-曲通X-100体系共振瑞利散射法测定蛋白质 总被引:15,自引:0,他引:15
基于在TrtionX-100存在下,蛋白质对有机染料亮黄瑞利光散射的增强作用。拟定了测定蛋白质的瑞利光散射光,由于添加了TritonX-100,对不同的蛋白质,测定的灵敏度提高了5-11.8倍,线性范围在0-5.0mg/L之间,最低检测限为10.2μg/L。 相似文献
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动力学荧光法测定药物、水果、蔬菜中的维生素C 总被引:7,自引:1,他引:7
提出了动力学荧光法测定维生素C的新方法。该法基于脱氢抗坏血酸(DAsA)对还原型罗丹明B在钒(Ⅴ)催化下自动氧化的活化作用。在pH为3.7的HAc-NaAc缓冲溶液中,还原型罗丹明B在钒(Ⅴ)催化下的氧化反应速度与DAsA的浓度成正比,采用固定时间法,测定在λ_(ex)=554 nm,λ_(em)=580 nm时的荧光强度。DAsA的线性范围为0~4.0×10~(-7)mol/L, 检测限4.0×10~(-9)mol/L。用该法测定药物、水果、蔬菜中维生素C含量,回收率在93%~108%之间。 相似文献
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Chengjian Tan Yingtong Di Ye Wang Suo Gao Ningchuan Kong Jianxin Zhang Chunshun Li Xiaojiang Hao 《Tetrahedron letters》2008,49(21):3376-3379
Oldhamine A, a novel alkaloid with an unusual cyclopentadienyl anion in the fused-pentacyclic skeleton was isolated from the twigs of Daphniphyllum oldhami. The structure of oldhamine A was elucidated based on the spectroscopic data and the single-crystal X-ray diffraction crystallography. It is the first X-ray diffraction of the Daphniphyllum alkaloids with nitrogen-containing two pentacyclic rings. The inter-conversion between cyclopentadienyl anion and conjugated enolic unit was also conducted. 相似文献
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