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781.
A. Krishnamoorthy Vishwanath C. Narayanan T. G. Deepak 《Journal of Applied Mathematics and Computing》2007,25(1-2):389-405
In this paper, we study ak-out-of-n system with single server who provides service to external customers also. The system consists of two parts: (i) a main queue consisting of customers (failed components of thek-out-of-n system) and (ii) a pool (of finite capacityM) of external customers together with an orbit for external customers who find the pool full. An external customer who finds the pool full on arrival, joins the orbit with probability γ and with probability 1- γ leaves the system forever. An orbital customer, who finds the pool full, at an epoch of repeated attempt, returns to orbit with probability δ (< 1) and with probability 1- δ leaves the system forever. We compute the steady state system size probability. Several performance measures are computed, numerical illustrations are provided. 相似文献
782.
Exploring concomitant/conformational dimorphism in a difluoro‐substituted phosphoramidate derivative
Avantika Hasija Deepak Chopra 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(4):451-461
The concomitant occurrence of dimorphs of diphenyl (3,4‐difluorophenyl)phosphoramidate, C18H14F2NO3P, was observed via a solution‐mediated crystallization process with variation in the symmetry‐free molecules (Z′). The existence of two forms, i.e. Form I (block, Z′ = 1) and Form II (needle, Z′ = 2), was characterized by single‐crystal X‐ray diffraction, differential scanning calorimetry and powder X‐ray diffraction. Furthermore, a quantitative analysis of the energetics of the different intermolecular interactions was carried out via the energy decomposition method (PIXEL), which corroborates with inputs from the energy framework and looks at the topology of the various intermolecular interactions present in both forms. The unequivocally distinguished contribution of strong N—H…O hydrogen bonds along with other interactions, such as C—H…O, C—H…F, π–π and C—H…π, mapped on the Hirshfeld surface is depicted by two‐dimensional fingerprint plots. Apart from the major electrostatic contribution from N—H…O hydrogen bonds, the crystal structures are stabilized by contributions from the dispersion energy. The closely related melting points and opposite trends in the calculated lattice energies are interesting to investigate with respect to the thermodynamic stability of the observed dimorphs. The significant variation in the torsion angles in both forms helps in classifying them in the category of conformational polymorphs. 相似文献
783.
In the present investigation a steady-state mathematical model is developed for a typical four stage CEHH bleaching sequence in Indian Pulp and Paper Industry. Each stage of the sequence is composed of chemical additions and mixing, reaction in a retention tower, and washing. Unit operation models were formulated using mass balances on liquor, fibres, kappa number, chemicals and COD based on the assumption of perfect mixing and quasi steady-state. The COD is used in this paper as an indication of the amount of effluent coming out from four bleaching stages. In order to validate the model, the simulated results are compared with the literature data; a good agreement is achieved between the simulated results with the literature data. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
784.
We study sandpile models with stochastic toppling rules and having sticky grains so that with a nonzero probability no toppling occurs, even if the local height of pile exceeds the threshold value. Dissipation is introduced by adding a small probability of particle loss at each toppling. Generically for the models with a preferred direction, the avalanche exponents are those of critical directed percolation clusters. For undirected models, avalanche exponents are those of directed percolation clusters in one higher dimension. 相似文献
785.
Sunil Chopra 《Annals of Operations Research》1994,50(1):143-171
In this paper, we consider the problem of packing Steiner trees in a graph. This problem arises during the global routing phase of circuit layout design. We consider various integer programming formulations and rank them according to lower bounds they provide as LP-relaxations. We discuss a solution procedure to obtain both lower and upper bounds using one of the LP-relaxations. Computational results to test the effectiveness of our procedures are provided. 相似文献
786.
A preferential interaction quadratic isotherm model for hydrophobic interaction chromatographic systems is presented in this paper. In this isotherm, the nonlinear effect of salt on the capacity factor is described using the preferential interaction model developed by Perkins et al. [J. Chromatogr. A, 766 (1997) 1]. This is then coupled with a quadratic nonlinear isotherm to describe nonlinear adsorption behavior at high solute concentrations. The resulting preferential interaction quadratic isotherm is examined for its ability to describe solute adsorption behavior under both linear and nonlinear conditions over a wide range of salt concentrations in HIC systems. The results indicate that this isotherm is well suited for predicting nonlinear adsorption behavior in HIC systems for both proteins and low-molecular mass HIC displacers. 相似文献
787.
P.N. Tandon R.C. Chopra A.P. Agnihotry R. Vijayaraghavan S.K. Malik 《Solid State Communications》1974,15(10):1671-1674
The hyperfine field at samarium nuclear site induced by the paramagnetism of 4? electrons has been measured in Eu(Sm)Al2 using perturbed angular correlation technique and found to have a negative sign which is in striking contrast to the positive sign expected in free Sm3+ ion. It amounts to a large negative Knight shift at samarium nuclear site in this alloy. 相似文献
788.
789.
Phonon dispersion of Mg2Pb, a II–IV compound having an anti-fluorite structure, has been studied by a non-central model using CGW type angular forces. Good agreement with experimentally measured frequencies is observed. The results are also compared with those obtained for Mg2Sn.The author express their gratitude to Messrs. S. Guermah, O. El Kechai, Directors, INES en Electrotechnique and Génie-Civil of Tizi-Ouzou, respectively, for encouragement and facilities provided. 相似文献
790.
The advantages and disadvantages of the clipped correlator for photoelectric correlation measurements are analysed. A scheme
is suggested by which the problem of inversion (an inherent disadvantage of clipping) is obviated. With the availability of
surface acustic wave (SAW) delay lines, we would like to point out that one can make an almost ideal photon correlator. 相似文献