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151.
Wain AJ Compton RG Le Roux R Matthews S Yunus K Fisher AC 《The journal of physical chemistry. B》2006,110(51):26040-26044
The design, fabrication, and characterization of microfluidic channel flow devices for in situ simultaneous hydrodynamic electrochemical ESR is reported. The microelectrochemical reactors consist of gold film electrodes situated within rectangular ducts of height 350 microm and widths in the range 500-2000 microm. The small dimensions of the channels result in minimal dielectric loss when centralized within a cylindrical TE011 resonant cavity, leading to a high level of sensitivity. This is demonstrated by using the one-electron oxidation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in acetonitrile as a model system, wherein the ESR spectra obtained for the corresponding stable radical cation are of a high signal-to-noise ratio. Signal intensity is measured as a function of flow rate for this system, and the behavior is validated by means of 3-dimensional numerical modeling of the hydrodynamic flow profile. 相似文献
152.
Path relinking for the vehicle routing problem 总被引:3,自引:0,他引:3
This paper describes a tabu search heuristic with path relinking for the vehicle routing problem. Tabu search is a local search
method that explores the solution space more thoroughly than other local search based methods by overcoming local optima.
Path relinking is a method to integrate intensification and diversification in the search. It explores paths that connect
previously found elite solutions. Computational results show that tabu search with path relinking is superior to pure tabu
search on the vehicle routing problem. 相似文献
153.
We study the space of functions on a finite-dimensional vector space over a field of odd order as a module for a symplectic group. We construct a basis of this module with the following special properties. Each submodule generated by a single basis element under the symplectic group action is spanned as a vector space by a subset of the basis and has a unique maximal submodule. From these properties, the dimension and composition factors of the submodule generated by any subset of the basis can be determined. These results apply to incidence geometry of the symplectic polar space, yielding the symplectic analogue of Hamada's additive formula for the p-ranks of the incidence matrices between points and flats. A special case leads to a closed formula for the p-rank of the incidence matrix between the points and lines of the symplectic generalized quadrangle over a field of odd order. Together with earlier results on the 2-ranks, this result completes the determination of the p-ranks for these quadrangles. 相似文献
154.
Boundary value methods for solving ordinary differential equations require the solution of non-symmetric, large and sparse linear systems. In this paper, these systems are solved by using the generalized minimal residual (GMRES) method. A circulant-block preconditioner is proposed to speed up the convergence rate of the GMRES method. Theoretical and practical arguments are given to show that this preconditioner is more efficient than some other circulant-type preconditioners in some cases. A class of waveform relaxation methods is also proposed to solve the linear systems. 相似文献
155.
This paper considers the short- and long-memory linear processes with GARCH (1,1) noises. The functional limit distributions of the partial sum and the sample autocovariances are derived when the tail index α is in (0,2), equal to 2, and in (2,∞), respectively. The partial sum weakly converges to a functional of α-stable process when α<2 and converges to a functional of Brownian motion when α≥2. When the process is of short-memory and α<4, the autocovariances converge to functionals of α/2-stable processes; and if α≥4, they converge to functionals of Brownian motions. In contrast, when the process is of long-memory, depending on α and β (the parameter that characterizes the long-memory), the autocovariances converge to either (i) functionals of α/2-stable processes; (ii) Rosenblatt processes (indexed by β, 1/2<β<3/4); or (iii) functionals of Brownian motions. The rates of convergence in these limits depend on both the tail index α and whether or not the linear process is short- or long-memory. Our weak convergence is established on the space of càdlàg functions on [0,1] with either (i) the J1 or the M1 topology (Skorokhod, 1956); or (ii) the weaker form S topology (Jakubowski, 1997). Some statistical applications are also discussed. 相似文献
156.
Jang H. C. Sin K. R. Paek H. R. Jang Y. M. Jong S. H. 《Russian Journal of Organic Chemistry》2020,56(12):2228-2235
Russian Journal of Organic Chemistry - N-Aryl-substituted pyrrolidine derivatives were synthesized via tributylphosphine-catalyzed sequential Michael addition of α-aminonitriles and methyl... 相似文献
157.
Vaikuong Sin 《高等学校计算数学学报(英文版)》2007,(1)
A matrix is said to be stable if the real parts of all the eigenvalues are negative. In this paper, for any matrix An, we discuss the stability properties of T. Chan’s preconditioner cU (An) from the viewpoint of the numerical range. An application in numerical ODEs is also given. 相似文献
158.
Ee GC Teh SS Mah SH Rahmani M Taufiq-Yap YH Awang K 《Molecules (Basel, Switzerland)》2011,16(9):7249-7255
Our ongoing investigations on the stem bark of Mesua beccariana afforded a novel cyclodione coumarin, beccamarin, together with two known xanthones, mesuarianone, mesuasinone, two anthraquinones, 4-methoxy-1,3,5-trihydroxy-anthraquinone and 2,5-dihydroxy-1,3,4-trimethoxyanthraquinone and one coumarin, mammea A/AB. The structures were elucidated by 1D and 2D NMR and MS techniques. 相似文献
159.
We study sharp permutation groups of type {0, k} and observe that, once the isomorphism type of a point stabilizer is fixed, there are only finitely many possibilities for such a permutation group. We then show that a sharp permutation group of type {0, k} in which a point stabilizer is isomorphic to the alternating group on 5 letters must be a geometric group. There is, up to permutation isomorphism, one such permutation group. 相似文献
160.
Zian Cheak Tiui ;Arman Zarei ;Sin Jin Tan ;Harith Ahmad ;Sulaiman Wadi Harun 《中国物理快报》2014,(12):56-58
Q-switched pulsed laser systems operating in the eye-safe wavelength region (λ〉 1.4 μm) are promis- ing for applications such as light detection and ranging (lidar), differential absorption lidar, optical communi- cation, sensor and instrumentations. Fiber lasers are particularly attractive for such applications due to the fact that the beam quality can be independent of output power and they can be robustly engineered. There is an increasing interest in Q-switched erbium- doped fiber lasers (EDFLs), which can be generated by using either active or passive techniques. Com- pared with the actively Q-switched ones, passively Q- switched EDFLs have attracted much attention for their advantages of compactness, low cost, flexibility and simplicity of design. Different kinds of saturable absorbers, such as the transition metal-doped crys- tals and semiconductor quantum-well structures, have been applied to realize Q-switched EDFLs.How- ever, when they are used in the laser cavity, additional alignment devices, such as lens, mirrors or U-bench units, have to be applied. This may increase the in- sertion loss and the complexity of the laser cavity. 相似文献