Solving the continuous space p-centre problem: planning application issues

^** 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.     

加载电磁带隙结构的平切圆锥等角螺旋天线

 加载电磁带隙的平切圆锥等角螺旋（EAS-EBG)天线可以在很宽的频带范围内提高辐射增益。建立了平切等角螺旋锥体（EAS）天线的基本模型,并用HFSS对其进行了仿真。研究了一种加载电磁带隙结构的平切圆锥等角螺旋锥体天线。该天线是在保持原平切等角螺旋锥体天线外形不变的情况下,加载了小型化的电磁带隙结构,以提高增益并保持共形化。仿真结果表明:加载电磁带隙结构的模型增益在5～12 GHz带宽下可以提高1～3 dB,并且轴比特性基本不变。     

Paxiphyllines A and B, new alkaloids from Daphniphyllum paxianum

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.     

一步法合成(±)-圆柚酮的简便方法

以巴伦西亚烯 1为原料 ,采用 H2 O2 /(H3 C) 3 COH/Na Cl O氧化体系来制备圆柚酮 2。得到的粗产品经进一步分离提纯后得高纯度的圆柚酮产品 2。其结构经 IR、MS、1H NMR和 13 C NMR证实。该合成路线简单 ,后处理方便 ,环境污染小 ,总收率为 70 .6 % ,是一个比较理想的合成方法     

亮黄-曲通X-100体系共振瑞利散射法测定蛋白质

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。     

Oldhamine A, a novel alkaloid from Daphniphyllum oldhami

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.     

动力学荧光法测定药物、水果、蔬菜中的维生素C

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。