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排序方式: 共有937条查询结果,搜索用时 15 毫秒
111.
Mehdi Dehghan Masoud Hajarian 《Journal of Computational and Applied Mathematics》2011,235(15):4325-4336
Many problems in the areas of scientific computing and engineering applications can lead to the solution of the linear complementarity problem LCP (M,q). It is well known that the matrix multisplitting methods have been found very useful for solving LCP (M,q). In this article, by applying the generalized accelerated overrelaxation (GAOR) and the symmetric successive overrelaxation (SSOR) techniques, we introduce two class of synchronous matrix multisplitting methods to solve LCP (M,q). Convergence results for these two methods are presented when M is an H-matrix (and also an M-matrix). Also the monotone convergence of the new methods is established. Finally, the numerical results show that the introduced methods are effective for solving the large and sparse linear complementary problems. 相似文献
112.
The comparative electrochemical behavior of self-assembled monolayers of two Schiff's bases, 2-{[(Z)-1-(3-furyl)methylidene]amino}-1-benzenethiol (FMAB) and 2-{[(2-sulfanylphenyl)imino]methyl}phenol (SIMP) on a bare gold electrode (Au FMAB SAM-modified electrode and Au SIMP SAM-modified electrode, respectively), was investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy in a 0.1 mol L(-1) KCl solution that contains 5.0 × 10(-3) mol L(-1) [Fe(CN)(6)](3-/4-). The results revealed that the modified electrodes showed an electrocatalytic activity toward the anodic oxidation of dopamine by a marked enhancement in the current response and lower overpotential (60 and 90 mV for the Au FMAB and Au SIMP SAM-modified electrodes, respectively) in phosphate buffer solution at pH 6.0. The Au SIMP SAM-modified electrode was applied successfully to the determination of dopamine in the presence of a high concentration of ascorbic acid. Selective detection was realized in total elimination of ascorbic acid response-a method different from the ones based on the potential separations. The detection limit of dopamine was 5.0 × 10(-8) mol L(-1) in a linear range from 1.0 × 10(-6) to 1.2 × 10(-4) mol L(-1) in the presence of 1.0 × 10(-3) mol L(-1) ascorbic acid. The interference studies also showed that the Au SIMP SAM-modified electrode exhibited good selectivity in the presence of a large excess of uric acid and could be employed for the determination of dopamine in pharmaceutical formulations, plasma samples and human urine with adequate selectivity and precision. 相似文献
113.
Hanif MA Al-Maskri AY Al-Mahruqi ZM Al-sabahi JN Al-Azkawi A Al-Maskari MY 《Natural product communications》2011,6(10):1451-1454
Three wild Omani plants, Moringa peregrina, Acacia nilotica and Rhazya stricta, were selected for the present study. Na, K and Ca contents were determined using flame photometric analysis. M. peregrina seeds (22.5 mg/g) and pods (27.7 mg/g) had higher Na contents than A. nilotica (0.33 mg/g) and R. stricta (0.30 mg/g), whereas the K and Ca contents of R. stricta were significantly higher than those of the other two plants. The protein content was lowest in R. stricta (9.8%) and highest in M peregrina seeds (21.0%). The highest total phenolic contents (TPC) were found in M. peregrina seeds (350.3 mg/g) and the lowest in A. nilotica (66.1 mg/g). The major component of M. peregrina seed oil was oleic acid (74.7%). Gas chromatographic-mass spectrometric analysis (GC-MS) revealed that octadecanal (30.9%) was the major compound in A. nilotica. The presence of various phenolics and flavonoids in M. peregrina, A. nilotica and R. stricta were confirmed by high performance liquid chromatography (HPLC). 相似文献
114.
Masoud Mahjouri‐Samani Ryan Gresback Mengkun Tian Kai Wang Alexander A. Puretzky Christopher M. Rouleau Gyula Eres Ilia N. Ivanov Kai Xiao Michael A. McGuire Gerd Duscher David B. Geohegan 《Advanced functional materials》2014,24(40):6365-6371
Synthesis of functional metal chalcogenide (GaSe) nanosheet networks by stoichiometric transfer of laser‐vaporized material from bulk GaSe targets is presented. Uniform coverage of interconnected, crystalline, and photoresponsive GaSe nanosheets in both in‐plane and out‐of‐plane orientations are achieved under different ablation conditions. The propagation of the laser‐vaporized material is characterized by in situ ICCD‐imaging. High (1 Torr) Ar background gas pressure is found to be crucial for the stoichiometric growth of GaSe nanosheet networks. Individual 1–3 layer GaSe triangular nanosheets of ≈200 nm domain size are formed within 30 laser pulses, coalescing to form nanosheet networks in as few as 100 laser pulses. The thickness of the deposited networks increases linearly with pulse number, adding layers in a two‐dimensional (2D) growth mode. GaSe nanosheet networks show p‐type semiconducting characteristics with mobilities reaching as high as 0.1 cm2V?1s?1. Spectrally‐resolved photoresponsivities and external quantum efficiencies range from 0.4 AW?1 and 100% at 700 nm, to 1.4 AW?1 and 600% at 240 nm, respectively. Pulsed laser deposition under these conditions appears to provide a versatile and rapid approach to stoichiometrically transfer and deposit functional networks of 2D nanosheets with digital thickness control and uniformity for a variety of applications. 相似文献
115.
Rock Porous Structure Characterization: A Critical Assessment of Various State-of-the-Art Techniques
Razavifar Mehdi Mukhametdinova Aliya Nikooee Ehsan Burukhin Alexander Rezaei Amin Cheremisin Alexey Riazi Masoud 《Transport in Porous Media》2021,136(2):431-456
Transport in Porous Media - The porous structure of geomaterials is of utmost importance for various industrial and natural processes. In this study, various conventional porous structure... 相似文献
116.
Using fully implicit conservative statements to close open boundaries passing through recirculations
The numerical solution of the fluid flow governing equations requires the implementation of certain boundary conditions at suitable places to make the problem well‐posed. Most of numerical strategies exhibit weak performance and obtain inaccurate solutions if the solution domain boundaries are not placed at adequate locations. Unfortunately, many practical fluid flow problems pose difficulty at their boundaries because the required information for solving the PDE's is not available there. On the other hand, large solution domains with known boundary conditions normally need a higher number of mesh nodes, which can increase the computational cost. Such difficulties have motivated the CFD workers to confine the solution domain and solve it using artificial boundaries with unknown flow conditions prevailing there. In this work, we develop a general strategy, which enables the control‐volume‐based methods to close the outflow boundary at arbitrary locations where the flow conditions are not known prior to the solution. In this regard, we extend suitable conservative statements at the outflow boundary. The derived statements gradually detect the correct boundary conditions at arbitrary boundaries via an implicit procedure using a finite element volume method. The extended statements are validated by solving the truncated benchmark backward‐facing step problem. The investigation shows that the downstream boundary can pass through a recirculation zone without deteriorating the accuracy of the solution either in the domain or at its boundaries. The results indicate that the extended formulation is robust enough to be employed in solution domains with unknown boundary conditions. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
117.
在新兴便携式应用中集成Li-xx充电管理元件 总被引:1,自引:0,他引:1
MasoudBeheshti 《电子设计应用》2003,(5):61-63
新兴的便携式产品在提高功能与性能的同时,体积变得越来越小巧。因此,OEM 厂商希望能够缩小包括电池充电管理等电源管理功能所需要的空间。本文将探讨高度集成充电控制元件带来的挑战及优势,同时将详细说明该领域中的最新产品与 IC 组件。充电控制中的3“C”充电控制与管理是所有采用了可充电电池的便携式设计中的关键功能。先进的设计技术需确保满足以下3项关键要求。电池安全 (Cell Safety)此项要求不单单限于满足电池制造商建议的、在充电最后阶段±1%的电压调整容限要求,而且还包含了其他功能,如:可安全处理深放电电池的预处… 相似文献
118.
New square-planar Cu(II) complexes of 3,11-dimethyl-3,11-dinitro-1,5,9,13-tetraazacyclohexadecane and 1,11-diamino-6-methyl-6-nitro-4,8-diazaundecane cations have been prepared from the one-pot template condensation of [Cu(pn)2]2+ (pn=1,3-diaminopropane) in MeOH with CH2O and EtNO2 in the presence of a noncoordinating base. Reduction of the nitro group in the (3,11-dimethyl-3,11-dinitro-1,5,9,13-tetraazacyclohexadecane)copper(II) cation, may be achieved by Zn/acid reduction. The Cu(II) complex of the reduced form of the ligand, namely (3,11-diammonio-3,11-dimethyl-1,5,9,13-tetraazacyclohexadecane)copper(II), has also characterized. With the macrocyclic ligand, rac and meso isomers have been identified, the meso form being the major product. Elemental analyses, i.r. and u.v.–vis. spectroscopy, f.a.b. mass spectra conductometric, magnetic measurements and cyclic voltammetry have been used to characterize the complexes. 相似文献
119.
A computational method has been developed to predict the turbulent Reynolds stresses and turbulent heat fluxes in ducts by different turbulence models. The turbulent Reynolds stresses and other turbulent flow quantities are predicted with a full Reynolds stress model (RSM). The turbulent heat fluxes are modelled by a SED concept, the GGDH and the WET methods. Two wall functions are used, one for the velocity field and one for the temperature field. All the models are implemented for an arbitrary three‐dimensional channel. Fully developed condition is achieved by imposing cyclic boundary conditions in the main flow direction. The numerical approach is based on the finite volume technique with a non‐staggered grid arrangement. The pressure–velocity coupling is handled by using the SIMPLEC‐algorithm. The convective terms are treated by the van Leer scheme while the diffusive terms are handled by the central‐difference scheme. The hybrid scheme is used for solving the ε equation. The secondary flow generation using the RSM model is compared with a non‐linear k–ε model (non‐linear eddy viscosity model). The overall comparison between the models is presented in terms of the friction factor and Nusselt number. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
120.
Masoud Kasraian 《International Journal of Infrared and Millimeter Waves》1994,15(11):1923-1936
An analytical treatment of the second-order Bragg interaction is presented for the transverse magnetic mode of a dielectric film waveguide having gratings on both the film-cover and the film-substrate interfaces. Four canonical equations that describe the interactions of two guided waves propagating in the opposite directions in the film and the normally incident and radiated free waves in the cover and the substrate are deduced. 相似文献