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991.
Evgueni Gordienko Raúl Montes-De-Oca Adolfo Minjárez-Sosa 《Mathematical Methods of Operations Research》1997,45(2):245-263
The aim of the paper is to show that Lyapunov-like ergodicity conditions on Markov decision processes with Borel state space and possibly unbounded cost provide the approximation of an average cost optimal policy by solvingn-stage optimization problems (n = 1, 2, ...). The used approach ensures the exponential rate of convergence. The approximation of this type would be useful to find adaptive procedures of control and to estimate stability of an optimal control under disturbances of the transition probability.Research supported in part by Consejo Nacional de Ciencia y Tecnologia (CONACYT) under grant 0635P-E9506.Research supported by Fondo del Sistema de Investigatión del Mar de Cortés under Grant SIMAC/94/CT-005. 相似文献
992.
Effect of high gamma irradiation on track properties of PADC (Homalite) has been studied in the dose range of 101–106 Gy. The properties like bulk-etch rates and track-etch rates of the detector are found to increase due to gamma exposure. Etching efficiency of the detector increases due to exposure and it is significant at the dose higher than 103 Gy. Another track property, the critical angle, is also influenced by gamma exposure and is found to decrease with increasing dose. In all cases it is observed that the post-gamma exposure has greater effect than the pre-gamma exposure. The experimental results are presented and discussed in details. 相似文献
993.
吴奇学 《原子与分子物理学报》2002,19(1):109-111
应用双波理论描述均匀电场中D维q变形带电振子的运动,得到了振子各力学量随时间的演化方程. 相似文献
994.
M. M. C. G. Warmoeskerken P. van der Vlist V. S. Moholkar V. A. Nierstrasz 《Colloids and surfaces. A, Physicochemical and engineering aspects》2002,210(2-3):277-285
In domestic textile laundering processes, mass transfer and mass transport are often rate limiting. Therefore, these processes require a long processing time, large amounts of water and chemicals, and they are energy consuming. In most of these processes, diffusion and convection in the inter-yarn and intra-yarn pores of the fabric are limiting mass transport mechanisms. Intensification of mass transport, preferentially in the intra-yarn pores, is the key in the improvement of the efficiency of wet textile processes. Conventional methods of intensification of mass transport (e.g. operation at elevated temperatures) are not always feasible due to the undesired side effects such as fabric damage. Increasing the flow rate does not deliver the desired effect due to the multi-porous complex structure of textile materials. Van der Donck et al. [Tenside Surf. Det. 35 (1998) 119; 36 (1999) 222] reported that the deformation of yarns by placing a fabric in a pulsating flow or repeated mechanical elongation of the yarns improved mass transport. However, the additional mass transport caused by deformation is limited in practice. Power ultrasound is a promising technique to accelerate mass transport in textile materials. Several papers appeared in this field, which report an improvement in energy efficiency and processing time of the wet textile processes in the presence of ultrasound. In this paper, the different time and length scales are discussed in the intensification of the mass transport in laundry processes in the presence of ultrasound and compared with more conventional processes. It has been concluded that the characteristic mass transport rates in textiles can be increased by a factor of 6 applying ultrasound. 相似文献
995.
V. Ramaswami 《Queueing Systems》1990,6(1):229-260
We consider the single server queuesN/G/1 andGI/N/1 respectively in which the arrival process or the service process is a Neuts Process, and derive the matrix-exponential
forms of the solution of relevant nonlinear matrix equations for such queues. We thereby generalize the matrix-exponential
results of Sengupta forGI/PH/1 and of Neuts forMMPP/G/1 to substantially more general models. Our derivation of the results also establishes the equivalence of the methods of
Neuts and those of Sengupta. A detailed analysis of the queueGI/N/1 is given, and it is noted that not only the stationary distribution at arrivals but also at an arbitrary time is matrix-geometric.
Matrix-exponential steady state distributions are established for the waiting times in the queueGI/N/1. From this, by appealing to the duality theorem of Ramaswami, it is deduced that the stationary virtual and actual waiting
times in aGI/PH/1 queue are of phase type. 相似文献
996.
Horst Huck 《Journal of Solid State Electrochemistry》2002,6(8):534-539
Two types of non-integer electron-exchange numbers from uniform and reversible surface-redox reactions without side reactions
have been distinguished. The first being the apparent number, n
app, of the apparent faradaic charge corresponding to cyclovoltammetric peak areas above the interpolated baseline, and the second
the thermodynamically defined surface-redox valency, n', of Nernstian slopes of cyclovoltammetric peak potentials depending on different solution pH. An analytical expression has
been derived for n
app based on a simplified capacitive equivalent circuit and for n' using the potential-dependent free adsorption energies of the reactants involved. It should be pointed out that the different
experimental values of n
app and n' refer to the same integer number of electrons per molecule oxidized or reduced.
Electronic Publication 相似文献
997.
基于粗糙集与层次分析法的组合预测方法 总被引:3,自引:0,他引:3
本文在改进的属性约简启发式算法 ,即应用加权平均的属性重要度对属性进行约简的基础上 ,将粗糙集理论和层次分析相结合 ,给出了一种全新的组合预测方法 . 相似文献
998.
Experimental evidence shows that in the magnetoresistive manganite Ca1−xYxMnO3, ferromagnetic (FM) polarons arises in an antiferromagnetic (AF) background, as a result of the doping with yttrium. This hypothesis is supported in this work by classical Monte Carlo calculations performed on a model where FM double exchange and AF superexchange compete. 相似文献
999.
本文得到在局部Lipschiz条件下的布朗运动和泊松过程混合驱动的倒向随机微分方程的存在唯一性;同时也证明了布朗运动和泊松过程混合驱动的完全藕合的正倒向随机微分方程在局部Lipschitz条件下的解的存在唯一性。 相似文献
1000.
J. H. Lee In-Woo Chang S. J. Byun T. K. Hong K. Rhie W. Y. Lee Kyung-Ho Shin Chanyong Hwang S. S. Lee B. C. Lee 《Journal of magnetism and magnetic materials》2002,240(1-3):137-139
An unusually large enhancement of TMR at 77 K was observed in double barrier tunnel junctions (DBTJ). This is explained with extended Julliere's model which yields a twice larger TMR value. When the spin coherence length is much smaller at higher temperature, DBTJ is shown to work as a series of two single barrier tunnel junctions. 相似文献