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71.
72.
Filiz Taneri Tamer Güneri Zolt%aacute;n Aigner Michael Kata 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):257-260
Highly-soluble cyclodextrin derivatives, such as hydroxypropyl--cyclodextrin(HP--CD) and methyl--cyclodextrin (MEB), were tested as solubilizingagents for ketoconazole, with the aim of improving the physicochemical andbiopharmaceutical properties of this lipophilic imidazole antifungal agent. Productswere prepared in four molecular ratios by physical mixing, kneading and spray-dryingmethods. The kneaded products in a ratio of 1:2 and the spray-dried products exhibitedthe highest dissolution rates. The phase solubility diagrams of ketoconazole with thesecyclodextrins at 25 °C in water and in simulated intestinal medium wereconstructed. A solubility diagram of AL type was obtained with HP--CD, and one of AP type with MEB. The complexes were characterized by thermal methods(DSC, TG, DTG and DTA). Multicomponent systems were prepared with tartaric acid.The effects of water-soluble polymers, e.g., polyvinylpyrrolidone, on the aqueous solubility of ketoconazole were investigated. Particle size distribution, surface area, partition coefficient, heat of dissolution and wettability studies were also carried out. The formation of inclusion complexes was observed by means of thermoanalytical studies. 相似文献
73.
修正的分子连接性指数mL用于氯代苯、醇、酯的QSAR/QSRR研究 总被引:15,自引:0,他引:15
在分子拓扑理论的基础上,提出了1个改进的连接性指数气^mL并用气研究了氯代苯、醇、酯的正辛醇-水分配系数及气相色谱保留指数,^mL不仅对这些有机化合物有良好的结构选择性,而且与其正辛醇-水分配系数、气相色谱保留指数有良好的相关性;由方程得出的预测值与实验测定值之间能较好地吻合。 相似文献
74.
基于有限元法的面接触摩擦热流分配系数反推研究 总被引:1,自引:0,他引:1
本文基于有限元基础,利用红外测温-温度场有限元模拟-热电偶验证相结合的方法,反推得出摩擦副热流分配系数,分析了不同摩擦副材料、表面接触状况、散热条件对摩擦副热流分配系数的影响.分析表明:反推热流法为热流分配系数的计算提供了1个可行的方案;当摩擦副材料具有较好的减摩、抗黏着特性时,摩擦副运行稳定,摩擦副动态热流分配系数随时间变化平缓;摩擦副表面接触状况和散热条件对热流分配系数有明显的影响,利用本文提出的修正系数,可对理论公式进行修正. 相似文献
75.
We formulate binary fragmentation as a discrete stochastic process in which an integer mass k splits into two integer fragments j, , with rate proportional to the fragmentation kernel . We construct the ensemble of all distributions that can form in fixed number of steps from initial mass M and obtain their probabilities in terms of the fragmentation kernel. We obtain its partition function, the mean distribution and its evolution in time, and determine its stability using standard thermodynamic tools. We show that shattering is a phase transition that takes place when the stability conditions of the partition function are violated. We further discuss the close analogy between shattering and gelation, and between fragmentation and aggregation in general. 相似文献
76.
We briefly describe the theory of root transfer matrices for four-line models with the field in the new indexless form. We
use theoretical and numerical methods to reveal new effects in the theory of singular points and phase transitions. A substantial
part of the results is obtained using a numerical algorithm that drastically (at least exponentially) reduces the computational
complexity of Ising-type models by using the extremely sparse root transfer matrix.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 149, No. 2, pp. 281–298, November, 2006. 相似文献
77.
A second-order dynamic phase transition in a non-equilibrium Eggers urn model for the separation of sand is studied. The order parameter, the susceptibility and the stationary probability distribution have been calculated. By applying the Lee-Yang zeros method of equilibrium phase transitions, we study the distributions of the effective partition function zeros and obtain the same result for the model. Thus, the Lee-Yang theory can be applied to a more general non-equilibrium system. 相似文献
78.
In this paper properties and construction of designs under a centered version of the -discrepancy are analyzed. The theoretic expectation and variance of this discrepancy are derived for random designs and Latin hypercube designs. The expectation and variance of Latin hypercube designs are significantly lower than that of random designs. While in dimension one the unique uniform design is also a set of equidistant points, low-discrepancy designs in higher dimension have to be generated by explicit optimization. Optimization is performed using the threshold accepting heuristic which produces low discrepancy designs compared to theoretic expectation and variance.
79.
Krishnaswami Alladi Alexander Berkovich 《Transactions of the American Mathematical Society》2002,354(7):2557-2577
This paper has a two-fold purpose. First, by considering a reformulation of a deep theorem of Göllnitz, we obtain a new weighted partition identity involving the Rogers-Ramanujan partitions, namely, partitions into parts differing by at least two. Consequences of this include Jacobi's celebrated triple product identity for theta functions, Sylvester's famous refinement of Euler's theorem, as well as certain weighted partition identities. Next, by studying partitions with prescribed bounds on successive ranks and replacing these with weighted Rogers-Ramanujan partitions, we obtain two new sets of theorems - a set of three theorems involving partitions into parts (mod 6), and a set of three theorems involving partitions into parts (mod 7), .
80.
Equations for the solubility of gases and vapours into dry alcohols from methanol to decan‐1‐ol and into water‐saturated alcohols from butan‐1‐ol to decan‐1‐ol have been compared through the use of the Abraham solvation equation. It is shown that there are noticeable differences in solvation into the dry and wet alcohols, and that these differences become larger as the alcohols become smaller and take up more water. The two main factors that lead to the differences in solvation are the solute hydrogen‐bond basicity, B, and solute size, L. Increase in solute hydrogen‐bond basicity favours the wet alcohols and increase in solute size favours the dry alcohols. Solute hydrogen‐bond acidity plays no part, because the hydrogen‐bond basicity of water, wet alcohols and dry alcohols is almost the same. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献