二层供应链网络均衡模型的研究

利用均衡理论和二层规划理论来研究供应链网络均衡问题。针对供应链网络中上下层成员之间具有的Stackelberg博弈特征以及同层成员之间具有的非合作博弈特征,构建了二层供应链网络的均衡模型,该模型实际上一个均衡约束的二层规划问题。此外,为了使得供应链网络在整体上实现最优,本文还在模型中引入回收契约以协调供应链网络。最后,利用罚函数法对模型进行了求解,算例分析说明了模型的合理性和有效性。     

A New Method of Constructing the Functional Integral Directly from Hamiltonian in N (> 2)-Dimensional State space

Using the new method of constructing the functional path integral in state space, we accomplished the construction of the functional path integral in N(> 2)-dimensional state space, and illustrated it with the example of n = 3 dimensional case that leads to the same results with others.     

Effects of interactions and disorder on the compressibility of two-dimensional electron and hole systems

The compressibility χ of dilute two-dimensional electron and hole gases in GaAs semiconductor structures has been studied in the ranges of the interaction parameter r_s=1–2.5 and r_s=10–30 for the electron and hole system, respectively. Nonmonotonic dependence of χ^-1 with an upturn at low carrier densities is observed. Despite the large difference in r_s the behavior of χ^-1 in both systems can be accurately described by the theory of nonlinear screening of disorder by the carriers.     

石荠苧不同药用部位总黄酮及微量元素含量的测定

采用分光光度法测定了石荠芋不同药用部位总黄酮的含量,采用电感耦合等离子发射光谱法测定了其中微量元素的含量。结果表明,叶中总黄酮含量最高,根次之,茎最少;根、茎、叶中均含有Cu、Fe、Mn、Zn、Co等多种人体必需的微量元素,其中Fe含量最高,且叶中明显高于根、茎;3个部位均未检出有害重金属As,而Hg、Pb含量均未超标。该结果可为石荠芋不同药用部位的利用和药材的开发提供科学依据。     

Efficient hydrogenation of biomass-derived cyclic di-esters to 1,2-diols

The unprecedented homogeneous hydrogenation of cyclic di-esters, in particular biomass-derived glycolide and lactide, to the corresponding 1,2-diols is catalyzed by Ru(II) PNN (1) and Ru(II) CNN (2) pincer complexes under mild hydrogen pressure and (in the case of 1) neutral conditions. No racemization was observed when a chiral di-ester was used.     

The unique mechanism of analcime dissolution by hydrogen ion attack

Acidization is the process of injecting acid into porous oil bearing formations to dissolve minerals in the pore space and is a common technique to increase oil production. Analcime is a zeolite which is one of the minerals found in oil reservoirs in the Gulf of Mexico. This mineral is particularly troublesome during the injection of hydrochloric acid during stimulation of the well reservoir because of the precipitation of silicate and analcime dissolution products. To better understand the dissolution/precipitation process, a fundamental investigation of dissolution of analcime was carried out. Experiments establish that silicate precipitates completely from solution during analcime dissolution in hydrochloric acid and that the precipitation does not influence the dissolution kinetics. Comparison of Si and Al initial dissolution rates demonstrates that Al is selectively removed from the zeolite. The selective removal rate parameter is defined as the ratio of the measured Si dissolution rate to the stoichiometric Si dissolution rate. A new concept is introduced of using the selective removal rate parameter to delineate the mechanism of particle dissolution by demonstrating the influence of the Si-to-Al ratio. The mechanism comprises the removal of Si facilitated by the selective removal of Al, leading to the formation of undissolvable silicate particles. Consequently, the unique mechanism of analcime dissolution has general implications pertaining to how microporous materials dissolve.     

Scale inhibition study by turbidity measurement

The concept of a critical supersaturation ratio (CSSR) has been used to characterize the effectiveness of different types of scale inhibitors, inhibitor concentration, and precipitating solution pH in order to prevent the formation of barium sulfate scale. The scale inhibitors used in this work were aminotrimethylene phosphonic acid (ATMP), diethylenetriaminepentamethylene phosphonic acid (DTPMP), and phosphinopolycarboxylic acid polymer (PPCA). The CSSR at which barium sulfate precipitates was obtained as a function of time for different precipitation conditions and was used as an index to evaluate the effect of the precipitation conditions. The results showed that the CSSRs decrease with increasing elapsed time after mixing the precipitating solutions, but increases with increasing scale inhibitor concentration and solution pH. The CSSR varies linearly with the log of the scale inhibitor concentration and with the precipitating solution pH. A SEM analysis showed that the higher the scale inhibitor concentration and solution pH, the smaller and more spherical the BaSO4 precipitates. Analysis of the particle size distribution revealed that increasing the elapsed time, the scale inhibitor concentration, and precipitating solution pH, all produce a broader particle size distribution and a smaller mean diameter of the BaSO4 precipitates. DTPMP and PPCA were the most effective BaSO4 scale inhibitors per ionizable proton and the most effective on a concentration basis, respectively.     

Josephson effect without superconductivity: realization in quantum Hall bilayers

We show that a quantum Hall bilayer with the total filling nu = 1 should exhibit a dynamical regime similar to the flux flow in large Josephson junctions. This analogy may explain a conspicuous peak in the interlayer tunneling conductance [Phys. Rev. Lett. 84, 5808 (2000)]. The flux flow is likely to be spatiotemporally chaotic at low-bias voltage, which will manifest itself through broadband noise. The peak position can be controlled by an in-plane magnetic field.