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141.
142.
Md. Azizul Baten 《Journal of Mathematical Sciences》2011,177(3):329-344
This paper studies the production inventory problem of minimizing the expected discounted present value of production cost
control in a manufacturing system with degenerate stochastic demand. We establish the existence of a unique solution of the
Hamilton-Jacobi-Bellman (HJB) equation associated with this problem. The optimal control is given by a solution to the corresponding
HJB equation. 相似文献
143.
Gel polymer electrolytes were prepared using agar polymer host, NH4I, and I2 salts. The sample of agar paste with 1.0 M of NH4I and 0.2 μM of I2 exhibits the highest conductivity and lowest viscosity values at room temperature of (2.64?±?0.19)?×?10?3?S?cm?1 and 1.17?±?0.29 Pa?s, respectively. All of the gel polymer electrolytes display Arrhenian behavior, and the optimum agar paste gave the lowest activation energy of 0.25 eV. It also had a good physical appearance compared with the other samples. This gel polymer electrolyte had a good potential and was applicable to a role as electrolyte in ITO-ZnO (N719 dye)/agar paste?+?1.0 M NH4I?+?0.2 μM I2/Au-Pd-ITO dye-sensitized solar cell. 相似文献
144.
For 0 < α ≤ 1, analytic functions f(z) = z + a2z2 + a3z3 + … in the unit disk U are strongly starlike of order α if ¦arg {zf′ (z)/f(z)}¦ < πα / 2, z ∈ U. We find sharp estimates on the fourth and fifth coefficients of functions in this class. 相似文献
145.
《Solid State Communications》2006,137(1-2):63-66
High Al-content AlxGa1−xN films were deposited on (001) and (111) Si substrates at 1000 °C using high temperature AlN buffer layers. Experimental results show that AlxGa1−xN films grown on (111) Si substrates exhibit better crystalline quality than that in the films deposited on (001) Si substrates. Cracks were found in the high Al-content AlxGa1−xN/(111) Si samples but they were not observed in the AlxGa1−xN films grown on (001) Si substrates having the same film thicknesses and Al compositions. Based upon the results of X-ray diffraction (XRD) and transmission electron microscopy (TEM), it appears that mono-crystalline AlxGa1−xN films were achieved on (111) Si substrates while columnar structure was observed in the AlxGa1−xN/(001) Si samples. According to the depth profiles of AlxGa1−xN/Si samples using secondary ion mass spectroscopic (SIMS) analyses, enhanced Al inter-diffusion in the AlxGa1−xN/(001) Si samples was identified. Room temperature (RT) photoluminescence (PL) measurements of the AlxGa1−xN (x≦0.10)/(111) Si samples exhibit strong near band edge luminescence. The PL emission linewidth was found to decrease with the decrement of Al-content. 相似文献
146.
Farook Ahmad Ahmad Pauzi Mohd Yusof Martina Bainbridge Sulaiman Ab Ghani 《Electroanalysis》2007,19(5):541-548
Hydrogen peroxide (H2O2) was the main types of many peroxides produced in living mammalian cells that consumed oxygen. In the brain, the main source of H2O2 was the superoxide dismutase (SOD)‐catalyzed reaction in mitochondria. However, the level of H2O2 would be elevated through administration of control drugs and alcohol by dopamine metabolism of monoamine oxidase. In this study, a H2O2 microsensor was used to investigate the level of H2O2 in the brain striatum after administration of methamphetamine (MAP), morphine (MrP) or ethanol (Eth). The placement of microsensor in the brain was done at coordinates A/P 1.1 from bregma, M/L+2.6 and D/V‐1.5. A working potential of +0.05 V vs. Ag/AgCl was applied. The H2O2 concentration was measured direct from the current generated by its catalytic reaction at the electro active surface of the electrode. A significant increase of H2O2 level was observed after 7 successive injections of the controlled drugs or alcohol. The initial measurement of H2O2 is essential as excess dosage of H2O2 during treatment will contribute to the formation of neurotoxin oxygenated radicals. The H2O2 was the precursor of O2? and OH radicals. Thus, this study provided a mean to monitor H2O2 level in the brain. 相似文献
147.
《European Journal of Operational Research》2006,175(2):1311-1320
In this paper, we conduct simulation experiments to evaluate the performance of two alternative uses of the super-efficiency procedure in Data Envelopment Analysis (DEA). The first is for outlier identification and the second is for ranking efficient units. We find that the ranking procedure does not perform satisfactorily. In fact, the correlations between the true efficiency and the estimated super-efficiency are negative for the subset of efficient observations, and the conventional DEA model performs as well as the super-efficiency DEA model when all observations are considered. However, when data are contaminated with outliers, the use of the super-efficiency model to identify and remove outliers results in more accurate efficiency estimates than those obtained from the conventional DEA estimation model. 相似文献
148.
Surendran Ramasamy Abdul Rahman Mohamed Subhash Bhatia 《Reaction Kinetics and Catalysis Letters》2002,75(2):353-358
Oxidative coupling of methane for the production of ethylene was studied over Li-Ni/MgO catalyst in a fixed bed reactor. The influences of important reaction parameters such as temperature (T), methane/oxygen ratio (CH4/O2) in feed and space velocity of reactants (V/mcat) were studied over the conversion of methane, yields of ethylene and ethane and selectivity of ethylene formation. The reaction conditions were varied as 650 < T < 850oC, 0.83 x 10-6 < V/mcat < 2.92 x 10-6 m3/g s and 1 < CH4/O2 ratio < 8. 相似文献
149.
Sriwulan ADJI Rizky ROSJANUARDI 《数学学报(英文版)》2007,23(9):1639-1648
Let г^+ be the positive cone of a totally ordered abelian group г, and σa cocycle in г. We study the twisted crossed products by actions of г+ as endomorphisms of C^*-algebras, and use this to generalize the theorem of Ji. 相似文献
150.
Viscosities of solutions of polystyrene in toluene were measured for concentrations up to 400 kg m?3 at 298 K. Polymers of molecular weights ranging from 8.7 × 103 to 2.4 × 106 were used. It is observed that viscosity of the polymer solution increases with increasing concentration and molecular weight; the rate of increase is greater at higher values of the two parameters. A master curve for the system is constructed by using the experimental data for viscosity, concentration and molecular weight of the polymer. Regions of various polymer interactions in solution are identified. 相似文献