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131.
A finite difference procedure has been employed to obtain numerical predictions of recirculating flows in gas-stirred reactors. Sensitivity of alternative boundary conditions at gas-liquid interface as well as empirical constants of the turbulence model on the predicted flow field have been investigated. 相似文献
132.
D. Ghosh A. Deb M. Mondal S. Bhattacharyya J. Ghosh 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):77-80
Self-affine multiplicity scaling is investigated in the framework of two-dimensional factorial moment methodology using the
concept of the Hurst exponent (H). Our investigation on experimental data of the target-evaporated slow particles emitted in 32S-AgBr interactions at 200 AGeV and 28Si-AgBr interactions at 14.5 AGeV reveals that a better power law behavior is exhibited in self-affine analysis than self-similar
analysis. This work shows a clear evidence of self-affine target fragmentation.
Received: 22 October 2001 / Accepted: 6 March 2002 相似文献
133.
134.
The parallel and transverse components of diffusion constants of electrons in CdTe have been computed for fields of 30, 40, and 50 kV/cm using the Monte Carlo method. Results are presented for the velocity autocorrelation function and for the ac diffusion constants for two models of energy band structure and scattering constants, used earlier in the literature. The diffusion constants as obtained from the two models are significantly different, but none are in agreement with the available experimental results. 相似文献
135.
For a closed-shell molecule, a connection is drawn between two recent models for molecular shapes, namely, those based on
the second-order Jahn-Teller (SOJT) effect and the highest occupied molecular orbital (HOMO) postulate respectively. Two necessary
and sufficient conditions are derived within the molecular orbital framework for the approximation inherent in the SOJT model
to be valid. One of these conditions is akin to the HOMO postulate. 相似文献
136.
The extractive-photometric determination or iron(III) as a mixed-ligand complex with N -hydroxy-N, N′ -di-p -tolyl-p -toluamidine (HDTTA) and thiocyanate is described. The orange-red Waterinsoluble 1:1:2 (metal: HDTTA: SCN?) ternary complex formed in 0.1–0.6 M hydrochloric acid solutions is quantitatively extractable into benzene. The wavelength of maximum absorption, molar absorptivity and sensitivity of the colour system are 460nm, 12000 l. mole?1 cm?1 and 0.0046 μg Fe/cm 2respectively. The influence or foreign ions on the determination of iron has been studied. This method has also been applied to determine the iron content of several alloys. 相似文献
137.
K Deb 《The Journal of the Operational Research Society》2001,52(3):291-302
Goal programming is a technique often used in engineering design activities primarily to find a compromised solution which will simultaneously satisfy a number of design goals. In solving goal programming problems, classical methods reduce the multiple goal-attainment problem into a single objective of minimizing a weighted sum of deviations from goals. This procedure has a number of known difficulties. First, the obtained solution to the goal programming problem is sensitive to the chosen weight vector. Second, the conversion to a single-objective optimization problem involves additional constraints. Third, since most real-world goal programming problems involve nonlinear criterion functions, the resulting single-objective optimization problem becomes a nonlinear programming problem, which is difficult to solve using classical optimization methods. In tackling nonlinear goal programming problems, although successive linearization techniques have been suggested, they are found to be sensitive to the chosen starting solution. In this paper, we pose the goal programming problem as a multi-objective optimization problem of minimizing deviations from individual goals and then suggest an evolutionary optimization algorithm to find multiple Pareto-optimal solutions of the resulting multi-objective optimization problem. The proposed approach alleviates all the above difficulties. It does not need any weight vector. It eliminates the need of having extra constraints needed with the classical formulations. The proposed approach is also suitable for solving goal programming problems having nonlinear criterion functions and having a non-convex trade-off region. The efficacy of the proposed approach is demonstrated by solving a number of nonlinear goal programming test problems and an engineering design problem. In all problems, multiple solutions (each corresponding to a different weight vector) to the goal programming problem are found in one single simulation run. The results suggest that the proposed approach is an effective and practical tool for solving real-world goal programming problems. 相似文献
138.
Electron donor–acceptor interaction of the reverse micelle (RM) of TX-100 in CCl4 medium with a number of π-acceptors has been established by analysing the charge transfer (CT) absorption bands in the light of Mulliken's theory. Aggregation number (n) and operational critical micellisation concentration of the RM and formation constants of the RM–p-chloranil and RM-o-chloranil complexes have been determined by UV-visible spectrophotometry. Values of n thus obtained (20–30) are close to that of TX-100/cyclohexane dry reverse micelles determined by other methods and also to a theoretically calculated value of n for AOT/CCl4 dry RM. 相似文献
139.
A wide variety of 3-aminocoumarins have been synthesized in large scale from the corresponding 3-acetamidocoumarins by regioselective cleavage of carbon–nitrogen bond using 70% sulfuric acid under reflux conditions. The synthesized 3-aminocoumarins were further brominated regioselectively at the 4-position of 3-aminocoumarin using BDMS as brominating agent. 相似文献