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101.
Zulkarnain Zainal Mohd Zobir Hussein Arniza Ghazali 《Solar Energy Materials & Solar Cells》1996,40(4):347-357
SnS thin films were prepared by cathodic electrodeposition on ITO/glass and Ti substrates from a solution containing SnCl2 and thiosulphate ions. Cyclic voltammetry experiments were performed to elucidate the electrodic processes occurred when potentials were applied and to determine the optimum potential for electrodeposition. The photoactivity of the deposited films and their conduction types were evaluated using the photoelectrochemical technique. The bandgap energy and type of optical transitions were determined from optical absorbance data. Structural and compositional analysis were accomplished using X-ray diffractometry, electron dispersive analysis of X-ray, and X-ray photoelectron spectroscopy. The morphology of the films were examined using scanning electron microscopy. 相似文献
102.
Dongsheng Li Hussein Zbib Hamid Garmestani Xin Sun Mohammad Khaleel 《Computational Materials Science》2011,50(8):2496-2501
High energy particle irradiation of structural polycrystalline materials usually produces irradiation hardening and embrittlement. The development of predictive capability for the influence of irradiation on mechanical behavior is very important in materials design for next-generation reactors. A multiscale approach was implemented in this work to predict irradiation hardening of iron based structural materials. In the microscale, dislocation dynamics models were used to predict the critical resolved shear stress from the evolution of local dislocation and defects. In the macroscale, a viscoplastic self-consistent model was applied to predict the irradiation hardening in samples with changes in texture. The effects of defect density and texture were investigated. Simulated evolution of yield strength with irradiation agrees well with the experimental data of irradiation strengthening of stainless steel 304L, 316L and T91. This multiscale modeling can provide a guidance tool in performance evaluation of structural materials for next-generation nuclear reactors. 相似文献
103.
Reliability analysis has been considered as an important step in any system design process. A reliable electrical power system means a system which has sufficient power to feed the load demand during a certain period or, in other words, has small Loss of Load Probability (LOLP). LOLP is defined as an expected fraction of load not met by its power needs from electrical power system during its lifetime. Photovoltaic (PV)/Wind Energy System (WES) Hybrid Electric Power System (PV/WES HEPS) differs considerably from the Utility Grid (UG) in its performance and operating characteristics. With the interconnection of PV/WES as a HEPS into the UG, the fluctuating nature of the energy produced by these systems has a different effect on the overall system reliability than that of the fluctuating nature of energy produced by UG. Therefore, this paper presents a complete study, from reliability point of view, to determine the impact of interconnecting PV/WES HEPS into UG. Four different configurations of PV/WES/UG have been investigated and a comparative study between these four different configurations has been carried out. The overall system is divided into three subsystems, containing the UG, PV and WES. The generation capacity outage table has been built for each configuration of these subsystems. These capacity outage tables of UG, PV/UG, WES/UG and PV/WES/UG are calculated and updated to incorporate their fluctuating energy production. This paper also presents a fuzzy logic technique to calculate and assess the reliability index for each HEPS configuration under study. 相似文献
104.
Based on current voltage (I-Vg) and capacitance voltage (C-Vg) measurements, a reliable procedure is proposed to determine the effective surface potential Vd.Vg/ in Schottky diodes. In the framework of thermionic emission, our analysis includes both the effect of the series resistance and the ideality factor, even voltage dependent. This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-Vg measurements. The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg, which are important parameters directly related to the surface potential in the semiconductor, should be estimated within our approach to obtain more reliable information. 相似文献
105.
The influence of nonuniform current injection along the active region, on the linear operation of a quantum-dot semiconductor optical amplifier (QD-SOA) is investigated. For this purpose, we have utilized some functions to generate various nonuniform current injection profiles. These profiles have been considered in our numerical calculations, where the rate equation model is employed to construct different characteristics of the QD-SOA. We have found that the gain, as well as the crosstalk, of a QD-SOA is closely associated to the variance of the carrier density along the cavity. Simulation results show that nonuniform current injection can be used as a technique for gain enhancement as well as crosstalk suppression. 相似文献
106.
107.
Naceur Etteyeb Leila Dhouibi Mercedes Sanchez Cruz Alonso Carmen Andrade Ezzeddine Triki 《Journal of Materials Science》2007,42(13):4721-4730
The aim of this study is to investigate the viability of use of sodium phosphate (Na3PO4: SP), tetrasodium pyrophosphate (Na4P2O7: TSPP) and hydroxyethylidene-diphosphonic acid (C2H8O7P2: HEDP) as a non-toxic corrosion inhibitors of steel bars in alkaline media which simulate the electrolyte in the concrete
pores. The effectiveness of these phosphate compounds as corrosion inhibitors was investigated by measuring the corrosion
potentials, the polarization curves, the corrosion current densities, and the electrochemical impedance spectroscopy of steel
bars immersed for 30 days in saturated Ca(OH)2 solutions with and without chlorides. At the completion of the tests, the mass losses were determined in order to verify
the reliability of the electrochemical results. The results showed that phosphate compounds form a protective layer on the
steel surface when immersed in alkaline solution without chlorides. In the presence of chloride ions, the SP acts as an anodic
inhibitor and reduces the corrosion activity on steel. The HEDP shows lower efficiency, probably due to the decrease of the
pH and to the high [Cl−]/[inh] ratio used. Results obtained by electrochemical and gravimetric methods are in quite reasonable agreement. 相似文献
108.
Ming Y. Huang Hussein A. Abdullah Professor Chris R. Chatwin 《The International Journal of Advanced Manufacturing Technology》1996,11(3):214-220
A knowledge-based adaptive control environment is constructed to enhance the cost performance of a laser manufacturing system, this decreases the dependence on a skilled technician and reduces process development lead time. The control environment consists of two shells: a pre-process knowledge-based management system (KBMS) expert shell and an adaptive process controller. Experimental results are presented which show how effectively the adaptive control system improves process quality. 相似文献
109.
O. R. Asfar A. M. Hussein 《International journal for numerical methods in engineering》1989,28(5):1205-1216
A numerical method is presented for the-solution of linear systems of differential equations with initial-value or two-point boundary conditions. For y ′(x) = A (x) y (x) + f (x) the domain of interest [a,b] is divided into an appropriate number L of subintervals. The coefficient matrix A (x) is replaced by its value Ak at a point xk within the Kth subinterval, thus replacing the original system by the L discretized systems y k(x) = A k y k(x) + f k(x), k = 1,2,…, L. The fundamental matrix solution Φk(x, xk) over each subinterval is found by computing the eigenvalues and eigenvectors of each A k. By matching the solutions y k(x) at the L – 1 equispaced grid points defining the limits of the subintervals and the boundary conditions, the two-point problem is reduced to solving a system of linear algebraic equations for the matching constants characterizing the different y k(x). The values of y 1(a) and y L(b) are used to calculate the missing boundary conditions. For initial-value problems this method is equivalent to a one-step method for generating approximate solutions. By means of a coordinate transformation, as in the multiple shooting method,1 the method becomes particularly suitable for stiff systems of linear ordinary differential equations. Five examples are discussed to illustrate the viability of the method. 相似文献
110.
Mohammed Tahir Hussein 《国际水资源开发杂志》2001,17(2):227-235
The main objective of this article is to shed light on an important issue of water conservation-groundwater rights and legislation. Principles of groundwater rights are detailed and their applications to major aquifer systems, groundwater basins and wadis are discussed. Legislation and the clarification of water rights are vital for the sustainable development of groundwater. They are urgently needed in Saudi Arabia in particular and in all areas where demand exceeds supply. Legislation is one of the main pillars upon which any conservation policy is built. In this article a model is suggested for groundwater allocation in aquifers shared by more than one state. 相似文献