Competitive facility location on decentralized supply chains

This paper addresses a novel competitive facility location problem about a firm that intends to enter an existing decentralized supply chain comprised of three tiers of players with competition: manufacturers, retailers and consumers. It first proposes a variational inequality for the supply chain network equilibrium model with production capacity constraints, and then employs the logarithmic-quadratic proximal prediction–correction method as a solution algorithm. Based on this model, this paper develops a generic mathematical program with equilibrium constraints for the competitive facility location problem, which can simultaneously determine facility locations of the entering firm and the production levels of these facilities so as to optimize an objective. Subsequently, a hybrid genetic algorithm that incorporates with the logarithmic-quadratic proximal prediction–correction method is developed for solving the proposed mathematical program with an equilibrium constraint. Finally, this paper carries out some numerical examples to evaluate proposed models and solution algorithms.     

Locating a minisum circle in the plane

We consider the problem of locating a circle with respect to existing facilities in the plane such that the sum of weighted distances between the circle and the facilities is minimized, i.e., we approximate a set of given points by a circle regarding the sum of weighted distances. If the radius of the circle is a variable we show that there always exists an optimal circle passing through two of the existing facilities. For the case of a fixed radius we provide characterizations of optimal circles in special cases. Solution procedures are suggested.     

三乙烯四胺修饰啤酒废酵母吸附Hg（Ⅱ）的性能

将三乙烯四胺修饰到戊二醛交联的啤酒废酵母菌表面,合成了一种新的生物吸附剂。 研究了它吸附Hg(Ⅱ)的性能及影响吸附行为的因素。 结果表明,修饰啤酒废酵母菌吸附Hg(Ⅱ)的适宜条件是:2.5 ℃,吸附溶液的pH=2.8,吸附平衡时间20 min,对汞的吸附容量为132.6 mg/g,是未修饰菌的6.3倍。 该法静态处理含汞模拟废水(4.9~17.5 mg/L),汞去除率可达100%。 吸附动力学用准二级方程拟合,相关系数R2=0.999 9。 判定Langmuir模型更适合描述吸附Hg(Ⅱ)的过程,表明是单分子层吸附。     

主通道位置不固定的设施布局问题多目标优化模型及算法

以物流中心设施布局问题为对象,提出了考虑出入口及主通道位置不固定情况下的设施布局问题的多目标优化模型并设计了其改进的遗传算法。首先,以物料搬运成本最小、活动关系密切度最大和面积利用率最大为目标,构建了考虑出入口位置不固定条件下的具有I型主通道的设施布局多目标优化数学模型。然后,设计了一种改进的遗传算法,包括:改进的编码、解码方法,追加了解码修正操作,基于惩罚函数策略的适应度函数等。实例测试表明,本算法的执行效率高而且结果稳定,优化效果好,布局结果紧凑适用。     

带有惩罚和软容量约束的下界设施选址问题的双标准近似算法研究

研究带惩罚和软容量约束的下界设施选址问题. 扩展Guha等(Guha S, Meyerson A, Munagala K. Hierarchical placement and network design problems [C]//Proceedings of Foundations of Computer Science, 2000: 892328, DOI: 10.1109/SFCS.2000.892328)和Karger等(Karger D R,Minkoff M. Building steiner trees with incomplete global knowledge [C]//Proceedings of Foundations of Computer Science, 2000: 892329, DOI: 10.1109/SFCS.2000.892329)的工作到带有惩罚的下界约束设施选址问题,提出了一个新的双标准近似算法,得到了同样的近似比ρ(1+α)/(1-α). 进一步考虑带惩罚和软容量约束的下界设施选址问题,得到了近似比为2ρ(1+α)/(1-α)的双标准近似算法.     

FeCuNbSiB非晶粉体/IIR复合薄膜的拉伸及压缩应力阻抗效应

以FeCuNbSiB非晶粉体/IIR复合薄膜材料为研究对象,分别研究了该材料在固定测试频率为1KHz下的拉伸和压缩应力阻抗效应。其中压缩速度为0.01mm/s,压缩最大应力为1MPa;拉伸速度为0.05mm/s,拉伸最大应力为2.4MPa。同时,将2种测试过程在每隔50s时间,计算一个等效的拟合点,并将这些等效拟合点进行曲线拟合,获得相应的拟合曲线。接着我们又对拉伸应力阻抗及压缩应力阻抗等效拟合曲线经行求导处理,得出相应的能够表征应力阻抗的敏感性的函数Z’(σ)。试验结果表明:拉伸过程阻抗随着应力增大而降低,压缩过程阻抗随着应力增大而增大。由于该复合薄膜的基体是丁基橡胶,适合于微小应力敏感的测试。而压缩应力阻抗方面,其耐压强度相对耐拉强度大很多,论文中只讨论了压应力范围为0~1MPa的压应力阻抗效应。在微应力条件下,压应力阻抗敏感性能不及拉伸应力阻抗。而在大应力下其应力敏感特性较好。     

双水杨醛缩乙二胺合铜(Ⅱ)席夫碱金属配合物的合成及应用

合成了双水杨醛缩乙二胺合铜(Ⅱ)[Cu(Ⅱ)-EDBSAD]席夫碱金属配合物,并以该配合物为中性载体制备PVC膜电极,该电极对SCN-具有优良的电位响应特性,在pH=5.5磷酸盐缓冲溶液中,SCN-浓度在1.0×10-1～1.0×10-7 mol/L之间具有能斯特响应,校准曲线方程为Ｅ(mV)＝-51.75lg cSCN--255.29,检测下限为5.6×10-8 mol/L。 将电极用于废水中硫氰酸盐含量的测定,结果与高效液相色谱法基本一致。     

Synthesis and Crystal Structure of 1D Cd-amine Coordination Polymer and Its Luminescent Properties

A novel one dimension（1D） cadmium coordination polymer {[Cd（mpda）3]·2（NO3）}n（1） was synthesized via refluxing a mixture of tetradentate Schiff base ligand N,N＇-bis（2-pyridinylethylidene）phenylene-1,3-diamine（L） and Cd（NO3）2 in acetonitrile, whose structure was characterized by means of single crystal X-ray diffraction, FTIR spectroscopy, elemental analysis and proton nuclear magnetic resonance（1H NMR）. Center metal Cd（II） ion is six-coordinated by six nitrogen atoms from six different m-phenylenediamine（mpda）, giving rise to a [CdN6] octahe- dral coordination environment. The two adjacent cadmium centers are linked by three mpda molecules leading to the construction of 1D chain structure. The crystal structure is stabilized by N-H…O hydrogen bonds to form three-dimension supramolecule. Compound 1 exhibits intense yellow luminescence in solid state at 298 K（λem=554 nm）, which shows a blue shift at 77 K（ca. 147 nm）. Additionally, fluorescence characteristics of compound 1 were investigated in different solvents（polarity： DMSO〉CH3CN〉CH3OH〉CHC13〉toluene） at 298 and 77 K. The results show that the emission peak of compound 1 in solvent exhibits a slight bathochromic shift. However, the emission peaks of compound 1 in CH3OH and CHC13 are red shift compared with that in CH3CN. It is revealed that the lumi- nescence behavior of compound 1 depends on not only the polarity of solvent but also the hydrogen bonding proper- ties between solvent and solute. In addition, the emission peak of compound 1 in solution shows a red shift obviously at 77 K than that at 298 K（ca. 144-159 nm）, with the fluorescence lifetime increased at 77 K. The lifetime in DMSO at 77 K（r=12.470μs） was the longest one. The quantum yield of compoud 1 increases with increasing the polarity of solvent within a range of 1.8%-8.3 %.     

磁驱动准等熵平面压缩和超高速飞片发射实验技术原理、装置及应用

利用脉冲大电流产生随时间平滑上升的磁压,实现对样品的准等熵平面压缩和超高速飞片发射,是近十年来发展和完善起来的一种新型的强动态斜波加载技术(ramp wave loading).本文简述了其原理、加载装置及数据处理方法等方面的研究进展,同时着重评述利用该技术和方法开展高压物态方程、材料动力学响应方面的研究进展,并对该技术在冲击动力学、天体物理和高能量密度物理等方面的应用前景进行了展望.      

Synthesis,Crystal Structures and Catalysis of Dinuclear Cd(Ⅱ) Complexes Bridged by Unusual (N,O,O′)-Coordinated α-Amino Acids

Four dinuclear amino acid cadmium(Ⅱ) complexes [Cd₂(tren)₂(dl-alaninato)](ClO₄)₃·H₂O(Ⅰ), [Cd₂(tren)₂·(l-alaninato)](ClO₄)₃·H₂O(Ⅱ), [Cd₂(tren)₂(dl-phenylalaninato)](ClO₄)₃(Ⅲ) and [Cd₂(tren)₂(l-phenylalaninato)]· (ClO₄)₃(Ⅳ), constructed from mixed ligands of tris(2-aminoethyl)amine(tren) and racemic or natural amino acids( amino acids=dl- or l-alanine, and dl- or l-phenylalanine), have been synthesized and characterized by X-ray crystallography. The structural analysis of complexes Ⅰ and Ⅲ reveals that the cadmium centers are coordinated by one tren ligand and one amino acid molecule with the unusual (N,O,O′)-bridged mode, resulting in asymmetric chromophores of CdN₄O and CdN₅O in complex Ⅰ, CdN₄O₂ and CdN₅O in complex Ⅲ, respectively. The utility of the four complexes as efficient water-compatible Lewis acid catalysts for the direct aldol reaction in water was examined. The reaction proceeded smoothly to afford the corresponding β-hydroxy ketones in up to 99% yield. Moreover, the diastereoselectivity of the reaction favors the formation of the syn-isomers.