应用高温计测量氩等离子体温度

应用多通道辐射高温计测量了冲击产生的氩等离子体的温度,并与理论计算结果进行了比较.测量结果与Saha方程加Debye-Huckel修正模型的计算结果符合较好.     

Al2O3陶瓷复合靶抗长杆弹侵彻性能和机理实验研究

用DOP(depthofpenetration)实验研究了质量分数为 90 %的Al2 O3 陶瓷复合靶抗长杆弹侵彻性能。实验表明 :随陶瓷厚度的增加 ,以差分效益系数和靶平均阻力表征的陶瓷复合靶的抗长杆弹侵彻性能降低 ;盖板能增强陶瓷复合靶抗侵彻性能。对回收陶瓷和盖板的破坏特征分析表明 :长杆弹对陶瓷复合靶侵彻过程大致可分为初期侵彻和稳定侵彻两个阶段 ,但对薄靶和厚靶 ,两个阶段在整个侵彻过程中所占比重不同。     

Effect of the solvent nature on the course of quaternization of 3,5-diethoxycarbonyl-2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine

The effect of the solvent nature and temperature on the quaternization of 3,5-diethoxycarbonyl-2,6-di- methyl-4-(3-pyridyl)-1,4-dihydropyridine by lipophilic alkyl bromides has been investigated. By comparison of the solvent effect (acetone, acetonitrile, and 2-butanone) on the alkylation of the pyridine fragment of 3,5-diethoxycarbonyl-2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine it was established that conducting the reaction in acetonitrile at 81 °C is the most optimal.     

复形上一类混合约束的多目标规划问题

探讨了ｎ维复形上一类具有混合约束的多目标规划问题，并运用代数拓扑方法得出这类规划问题的有效解。     

Convex Polygons are Cover-Decomposable

We show that for any open convex polygon P, there is a constant k(P) such that any k(P)-fold covering of the plane with translates of P can be decomposed into two coverings.     

Saturating Sperner Families

A family ${\mathcal{F} \subseteq 2^{[n]}}$ saturates the monotone decreasing property ${\mathcal{P}}$ if ${\mathcal{F}}$ satisfies ${\mathcal{P}}$ and one cannot add any set to ${\mathcal{F}}$ such that property ${\mathcal{P}}$ is still satisfied by the resulting family. We address the problem of finding the minimum size of a family saturating the k-Sperner property and the minimum size of a family that saturates the Sperner property and that consists only of l-sets and (l + 1)-sets.     

电容去离子脱盐装置构型的研究进展

电容去离子(CDI)技术是一种新型的海水淡化技术,因其具有环境友好、操作简单和能耗低等优势而受到广大研究者的关注。在CDI技术中,电吸附的性能与装置的构型有着密切的联系。本文综述了目前常见的几种CDI装置,包括膜电容去离子(MCDI)、流动电极电容去离子(FCDI)、杂化电极电容去离子(HCDI)、反式电极电容去离子(i-CDI)以及脱盐电池(DB),对这几种装置的发展历程和装置构型进行介绍,最后,对CDI的装置构型在未来的研究发展方向进行了展望,以期为CDI装置在电脱盐领域的研究和应用提供参考。     

Synthesis of alkyl α- and β-<Emphasis Type="SmallCaps">d</Emphasis>-glucopyranoside-based chiral crown ethers and their application as enantioselective phase-transfer catalysts

Chiral monoaza-15-crown-5-type lariat ethers annelated to alkyl 4,6-O-benzylidene-α- and β-d-glucopyranosides have been synthesized. These macrocycles generated significant asymmetric induction as phase-transfer catalysts in a few two-phase reactions. The catalytic effect of the lariat ethers with methoxy, ethoxy, and i-propoxy substituents on C-1 of the sugar unit in both α and β positions was compared. In liquid–liquid two-phase reactions, the nature and position of the substituents did not have much effect. The α-anomers were somewhat more efficient in terms of enantioselectivity than the β forms. In asymmetric Darzens condensations, in the epoxidation of trans-chalcone, in the Michael addition of β-nitrostyrene and diethyl acetamidomalonate, and in the reaction of 2-benzylidene-1,3-indandione with diethyl bromomalonate, maximum enantioselectivities of 73, 94, 78, and 72%, respectively, were obtained in presence of glucopyranoside-based lariat ethers as catalysts.     

Online and Quasi-online Colorings of Wedges and Intervals

We consider proper online colorings of hypergraphs defined by geometric regions. We prove that there is an online coloring algorithm that colors N intervals of the real line using \({\Theta }(\log N/k)\) colors such that for every point p, contained in at least k intervals, not all the intervals containing p have the same color. We also prove the corresponding result about online coloring a family of wedges (quadrants) in the plane that are the translates of a given fixed wedge. These results contrast the results of the first and third author showing that in the quasi-online setting 12 colors are enough to color wedges (independent of N and k). We also consider quasi-online coloring of intervals. In all cases we present efficient coloring algorithms.