排序方式: 共有34条查询结果,搜索用时 62 毫秒
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We analyse the evolution of a two-stage chemical reaction betweentwo neighbouring plumes of reactants. Under the assumption thatthe plumes are approximately Gaussian we derive a system ofordinary differential equations for the total amount, the centroidand the variance of each reactant. We compare the solution ofthese equations with full numerical simulation of the reaction.Excellent agreement is obtained, with solution of the near-Gaussianmodel requiring considerably less computational effort thanthe full simulations. Of key importance is the yield of thereaction, and we discuss this feature in particular. 相似文献
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H. Beirão da Veiga F. Crispo C.R. Grisanti 《Journal of Mathematical Analysis and Applications》2011,377(1):216-227
The study of a very large class of linear and non-linear, stationary and evolutive partial differential problems in the half-space (or similar) under the slip boundary condition is reduced here to the much simpler study of the corresponding results for the same problem in the whole space. The approach is particularly suitable for proving new results in strong norms. To determine whether this extension is available, turns out to be a simple exercise. The verification depends on a few general features of the functional space X related to the space variables. Hence, we present an approach as much as possible independent of the particular space X. We appeal to a reflection technique. Hence a crucial assumption is to be in the presence of flat boundaries (see below). Instead of stating “general theorems” we rather prefer to illustrate how to apply our results by considering a couple of interesting problems. As a main example, we show that sharp vanishing viscosity limit results that hold for the evolution Navier-Stokes equations in the whole space can be extended to the slip boundary value problem in the half-space. We also show some applications to non-Newtonian fluid problems. 相似文献
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We consider the evolutionary Navier–Stokes equations with a Navier slip-type boundary condition, and study the convergence
of the solutions, as the viscosity goes to zero, to the solution of the Euler equations under the zero-flux boundary condition.
We obtain quite sharp results in the 2-D and 3-D cases. However, in the 3-D case, we need to assume that the boundary is flat. 相似文献
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AM Cardoso SM Alexandre CM Barros AJ Correia NM Nibbering 《Rapid communications in mass spectrometry : RCM》1999,13(19):1885-1888
The collision-induced dissociation (CID) of deprotonated arylalkylamines of general formula R(1)C(6)H(4)CHR(2)CH(2)NR(3)(2) (where R(1) = H, OH, F or NO(2); R(2) = H or OH; R(3) = H or CH(3)) generated by negative chemical ionization with H(2)O and D(2)O as ionizing reagents, is discussed. The negative chemical ionization mass spectra show that, in the absence of a hydroxy group in the aromatic ring, deprotonation takes place at the benzylic position whereas the proton is lost from the OH group when present. The nitro compound forms only M(-.) ions. The CID spectra of the deprotonated molecules show that fragmentations are strongly dependent on the structural features of the molecules, namely the presence or absence of substituents in the aromatic ring or aliphatic chain. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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This paper outlines the benefits of computational steering for high performance computing applications. Lattice-Boltzmann mesoscale fluid simulations of binary and ternary amphiphilic fluids in two and three dimensions are used to illustrate the substantial improvements which computational steering offers in terms of resource efficiency and time to discover new physics. We discuss details of our current steering implementations and describe their future outlook with the advent of computational grids. 相似文献
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We consider the 3-D evolutionary Navier–Stokes equations with a Navier slip-type boundary condition, see (1.2), and study
the problem of the strong convergence of the solutions, as the viscosity goes to zero, to the solution of the Euler equations
under the zero-flux boundary condition. We prove here, in the flat boundary case, convergence in Sobolev spaces W
k, p
(Ω), for arbitrarily large k and p (for previous results see Xiao and Xin in Comm Pure Appl Math 60:1027–1055, 2007 and Beir?o da Veiga and Crispo in J Math
Fluid Mech, 2009, doi:). However this problem is still open for non-flat, arbitrarily smooth, boundaries. The main obstacle consists in some boundary
integrals, which vanish on flat portions of the boundary. However, if we drop the convective terms (Stokes problem), the inviscid,
strong limit result holds, as shown below. The cause of this different behavior is quite subtle. As a by-product, we set up
a very elementary approach to the regularity theory, in L
p
-spaces, for solutions to the Navier–Stokes equations under slip type boundary conditions. 相似文献
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空气中激光烧蚀Cu产生等离子体发射光谱的研究 总被引:6,自引:3,他引:3
利用Q-开关Nd:YAG激光器产生的1.06 μm、10 ns的脉冲激光聚焦在空气中的Cu靶上,观测了激光诱导的Cu等离子体发射光谱.采用不同的激光能量,分析了波长范围为440 nm到540 nm的空间分辨发射光谱.在局部热力学平衡(LTE)条件近似下,根据谱线的相对强度,得到了等离子体电子温度约在104 K以上,给出了靶面附近电子温度的空间演化规律,并探讨了N(Ⅱ)500.52 nm谱线的谱线强度和半高全宽随激光能量的变化规律. 相似文献
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D. Crispo H. Pellet G. Fassbender H. H. B. Shepherd Carl Arnold J. König und C. Arnold 《Fresenius' Journal of Analytical Chemistry》1883,22(1):433-444
Ohne Zusammenfassung 相似文献
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