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91.
H. P. Benson 《Journal of Optimization Theory and Applications》2007,135(1):1-17
This article presents an algorithm for globally solving a sum of ratios fractional programming problem. To solve this problem,
the algorithm globally solves an equivalent concave minimization problem via a branch-and-bound search. The main work of the
algorithm involves solving a sequence of convex programming problems that differ only in their objective function coefficients.
Therefore, to solve efficiently these convex programming problems, an optimal solution to one problem can potentially be used
to good advantage as a starting solution to the next problem. 相似文献
92.
93.
Bo Xiang 《International Journal of Polymer Analysis and Characterization》2017,22(6):534-544
Acrylonitrile-styrene-acrylate (ASA) with controllable core–shell structure was prepared through three-stage seeded emulsion polymerization. A series of characterizations had been performed to study the effect of different core–shell ratios on the properties of ASA. The most interesting was that the impact strength of ASA exhibited a “wave” variation instead of a linear variation with the increasing loading content of poly(butyl acrylate) (PBA) core. Moreover, the threshold of impact strength appeared at 49.725?wt% PBA content, nearly 33 kJ/m2. To explain this unusual variation, an impact schematic was proposed. 相似文献
94.
《Journal of separation science》2017,40(21):4176-4190
Basic thermodynamic functions responsible for retention of new 1,2,4‐triazole derivatives exhibiting varied antiepileptic activity on cholesterol‐based stationary phase were determined. Evaluation of the Gibbs energy change, the change in enthalpy and the change in entropy was based on the van't Hoff relationship representing lnk versus 1/T . A detailed discussion of the van't Hoff equation, exploring the influence of the phase ratio on deviations from linearity in a van't Hoff plot is presented. We show chromatographic evidence to the question of how a varied mobile phase composition may cause different thermodynamic phase ratios. The analysis of data from a differential scanning calorimetry excluded any phase transitions of either the individual solutes or cholesterol stationary phase suspended in the mobile phase components within the studied temperature range. 相似文献
95.
Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pre... 相似文献
96.
在铌酸锂(LiNbO3,LN)中掺入摩尔分数为0.1;的CeO2,以提拉法从不同[Li]/[Nb]摩尔比([Li]/[Nb]=0.750,0.850,0.946,1.100)的熔体中生长出了Ce:LN晶体.测试了晶体的晶格常数、红外光谱和居里温度.结果表明:随着[Li]/[Nb]比的增加,晶体仍为三方的LN晶体,且晶格常数和晶胞体积没有发生大的变化,v(OH-)振动峰的位置依次向长波方向移动,居里温度依次增加,结构缺陷减少.由于Ce和[Li]/[Nb]比的协同作用,[Li]/[Nb]比为1.100的Ce:LN晶体已接近化学计量比,[Li]/[Nb]比为0.850的Ce:LN晶体的居里温度近似等于纯LN晶体.利用二波耦合光路测试了晶体的衍射效率、写入时间和擦除时间,计算了晶体的光折变灵敏度及动态范围.测试了晶体的抗光致散射能力,结果表明:[Li]/[Nb]比越高的Ce:LN晶体的光折变性能越好.并分析了不同[Li]/[Nb]比Ce:LN晶体光折变性能增强的机理. 相似文献
97.
98.
The Epps effect, the decrease of correlations between stock returns for short time windows, was traced back to the trading asynchronicity and to the occasional lead-lag relation between the prices. We study pairs of stocks where the latter is negligible and confirm the importance of asynchronicity but point out that alone these aspects are insufficient to give account for the whole effect. 相似文献
99.
Andreas P. Nawroth 《Physica A》2007,382(1):193-198
100.
Yukihiro Aiba Naomichi Hatano Hideki Takayasu Kouhei Marumo Tokiko Shimizu 《Physica A》2002,310(3-4):467-479
We first show that there are in fact triangular arbitrage opportunities in the spot foreign exchange markets, analyzing the time dependence of the yen–dollar rate, the dollar–euro rate and the yen–euro rate. Next, we propose a model of foreign exchange rates with an interaction. The model includes effects of triangular arbitrage transactions as an interaction among three rates. The model explains the actual data of the multiple foreign exchange rates well. 相似文献