Equilibrium contract selection strategy in chain-to-chain competition with demand uncertainty

This paper investigates the equilibrium contract selection problem for the dominant suppliers in two competing supply chains with stochastic and price-sensitive demand. The two suppliers, acting as the Stackelberg leaders, produce substitutable products and distribute them through each exclusive retailer, and can provide either a consignment contract or a wholesale-price contract. The equilibrium behaviours of the suppliers and retailers are investigated in three different scenarios: (1) the consignment contract scenario; (2) the wholesale-price contract scenario; and (3) the hybrid contract scenario. We prove that the equilibrium contracting strategy is of the threshold type: when the cost-share rates of the two retailers are above certain thresholds, both suppliers select consignment contracts; when the cost-share rates of the two retailers are lower than certain thresholds, both suppliers select wholesale-price contracts; when one retailer’s cost-share rate is above a certain threshold and the other is lower than a certain threshold, the supplier with large retailer’s cost-share rate selects the consignment contract and the other supplier with small retailer’s cost-share rate selects the wholesale-price contract. Furthermore, these thresholds depend on price sensitivities.     

新型一维链状配位聚合物{[Cu2(dhbd)(bipy)2]·10H2O}n的研究

采用水热法合成了标题配位聚合物{[Cu2(dhbd)(bipy)2]·10H2O}n(H4dhbd=2,3-二羟基丁二酸,bipy=2,2'-联吡啶),通过元素分析、红外光谱、热分析、X射线单晶衍射等技术对其进行了表征.配合物属单斜晶系,空间群C2/c,a=2.1965(4)nm,b=1.0671(2)nm,c=1.3662(3)nm,β=93.50(3)°,Z=4,R=0.0388.晶体的基本构建基元包含10个结晶H2O分子和由两个Cu(Ⅱ)原子、一个采用双二齿螯合配位的2,3-二羟基丁二酸根、两个2,2'-联吡啶形成具有C2旋转轴的U形双核单元,相邻的两个方向相反的U形双核单元通过双羧基O桥联形成沿c轴延伸的一维链;链间籍C-H…O和O-H…O氢键扩展为三维结构.配合物中呈现了一种2,3-二羟基丁二酸与过渡金属配位的新方式.     

事件空间中单面非Chetaev型非完整约束系统的Mei守恒量

研究事件空间中单面非Chetaev型非完整系统的Mei对称性和Mei守恒量.建立系统的运动微分方程,给出系统Mei对称性、弱Mei对称性、强Mei对称性的定义和判据,得到系统Mei守恒量的存在条件以及Mei守恒量的表达式.举例说明结论的应用.     

Novel 3-D Supramolecular Architectures Constructed from Zn^2＋ ions, Oxybis（4-benzoate） and Di（2-pyridyl）amine Ligands

Using the V-shaped oba dianions as bridging ligands and dpa molecules as terminal ligands, a new 1D helical coordination-polymeric chain, [Zn（oba）（dpa）]n [oba=oxybis（4-benzoate）, dpa=di（2-pyridyl）amine], was synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, UV-Vis and IR spectra, and TGA analysis. X-ray structural analysis revealed that, oba and dpa ligands played an important role in the self-assembly of the helical chains by providing potential supramolecular recognition sites for π-π aromatic stacking and hydrogen-bond interactions, resulting in the self-assembly of the （4,4） networks to give a 3-D supramolecular framework. The photoluminescence properties of the title compound were also investigated, showing intense blue photoluminescence properties at room temperature.     

Substituted metal carbonyls: [{{(p-MeOC6H4)2Te}M(CO)4}]2 (M = Mn or Re) in the presence of an O-atom transfer reagent

Two novel telluroether-disubstituted metal carbonyls, [(R₂Te)M(CO)₄]₂(M = Mn or Re; R = p-MeOC₆H₄), were prepared from [M₂(CO)₁₀] by an oxygen atom transfer. The axial CO is replaced by the telluroether when [M₂(CO)₁₀] reacts with a new kind of oxygen transfer reagent, R₂TeO, under mild conditions. The products were characterized by elemental analysis, i.r., ¹H- and ¹³C-n.m.r., and FAB-mass spectra. The configuration of the substituted carbonyl is unique, i.e. the 1, l-diax isomer.     

Kinetics and mechanism of the displacement of CO from Co4(CO)12 by phosphite ligands

Detailed kinetic data are reported for the monosubstitutions of Co₄(CO)₁₂ with phosphite ligands: P(OMe)₂Ph, P(OMe)Ph₂, P(OPr-i)₃ and P(OPh)₃, studied by conventional methods in CHCl₃ as solvent. The reaction rates suggest parallel pathways of dissociation (k ₁) and association (k ₂) and show predominantly an association pathway, the low values of H and negative S adding further support to the proposed mechanism. It is also confirmed that the reaction rates are retarded due to hydrogen-bonding between the H atom of CHC1₃ and the O atoms of the ligands [J. Wang et al., J. Coord. Chem., 23, 345 (1991)]. The results of the reactions of Co₄(CO)₁₂ with P(OMe)₃, P(OMe)₂Ph and P(OMe)Ph₂ in this paper suggest that no quantitative relation exists between the O atoms in the ligand and the reaction rate.     

基于2,3-二羟基丁二酸新配位方式构建的新颖双U形四核铜配合物[Cu4(dhbd)2(dpphen)4•2H2O]•8H2O

利用水热法合成了标题配合物Cu₄(dhbd)₂(dpphen)₄•2H₂O]•8H₂O(H4dhbd＝2,3-二羟基丁二酸, dpphen＝4,7-二苯基-1,10-邻菲咯啉), 通过元素分析、红外光谱、热分析、X射线单晶衍射等技术对其进行了表征. 晶体结构分析表明, 由于水的配位阻断, 2,3-二羟基丁二酸根仅通过单羟基氧桥联两个U形双核亚单元形成具有一个对称中心的双U形四核结构, 其中U型亚单元包含晶体学上不对称的2个Cu(II)原子、1个2,3-二羟基丁二酸根(dhbd)、2个4,7-二苯基-1,10-邻菲咯啉(dpphen)和1个配位H₂O分子. 毗邻的四核单元通过配位H2O分子和配位羟基O原子形成的R₂²(8)型环形氢键桥的连接, 沿a轴方向构建了四核单元交替相连的一维超分子链; 链间籍苯环的π-π堆积作用和晶格水分子氢键链的连接进一步扩展为具有隧道的三维结构. 配合物中呈现了一种2,3-二羟基丁二酸与过渡金属配位的新方式. 变温磁化率研究表明标题配合物具有弱的反铁磁耦合作用.     

PTCR纳米陶瓷粉及其烧结体的制备

The PTCR(positive temperature coefficient of resistance) nanosized ceramic powder was prepared by Sol-Gel process and characterized by XRD, DSC, SEM and BET techniques. The results showed that the nanopowder has an average crystallite size of 35nm with sphere-shaped, whose specific surface area is 27.80m²·g^-1 and the crystal structure is abnormal cubical perovskite phase at room temperature. In addition, the nanopowder was pressed into pellets and then sintered according to improved technique which was built based on the data of thermal analysis of the PTCR green-compact to yield PTCR ceramic materials with peculiar microstructure and higher properties, which has a resistivity at room temperature of ～20Ω·cm, a temperature coefficient of resistivity of ～19%·℃^-1, a withstand voltage intensity of >160V·mm^-1 and a resistivity jump of >10⁵.     

变质量Chetaev型非完整系统Appell方程Mei对称性的共形不变性与守恒量

研究了变质量Chetaev型非完整系统Appell方程Mei对称性的共形不变性和守恒量.在群的无限小变换下,定义了变质量Chetaev型非完整系统Appell方程Mei对称性和共形不变性,给出了该系统Mei对称性的共形不变性确定方程,并推导出系统相应的守恒量表达式.最后,给出了应用算例.     

基于刚性配体的一种铜(Ⅱ)配合物的合成、表征、晶体结构及DFT计算

利用二价铜盐和刚性多齿配体Hdpdapt合成了一种配位化合物[Cu(dpdapt)(cro)].CH3OH(1)(Hdpdapt=N,N′-di(2-pyridyl)-2,4-diamino-6-pheny-1,3,5-triazine,Hcro=CH2=C(Me)COOH)。用X-射线单晶衍射测定了该配合物的晶体结构:配合物属单斜晶系,P21/n空间群,通过反向平行的二聚体进一步组装成一维超分子链。此外,还测定了该配合物的热重性质。使用密度泛函理论(DFT)中的B3LYP方法对配合物1的几何参数进行优化,并解释其配位性质。通过B3LYP理论中NBO对配合物1和配体Hdpdapt的电子结构的分析,证实了配合物中的协同效应。