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1.
在设计数字信号处理器时我们经常要设计高性能的乘累加运算器,文章详细分析了乘累加运算器的结构,提出了其高性能设计方案并采用标准单元进行了实现,同时提出了DCT运算单元的高性能解决方案。 相似文献
2.
The crystal habit of fcc metal particles formed on an amorphous carbon film electrode in solution at different electrode
potentials is discussed. The fcc metal particles have different crystallographic habits depending on applied electrode potential;
that is, icosahedral and/or decahedral particles are formed at lower potentials, and fcc single-crystalline or polycrystalline
particles at higher potentials. It was found that decahedra and icosahedra of Cu-Au alloy particles are formed in the potential
region of underpotential deposition (UPD) of Cu at which only fcc Au single-crystalline particles and Au polycrystalline particles
appear. This is attributed to the charge transfer from the UPD Cu ions to the Au overlayer of Cu-Au alloy particles. The formation
of decahedral and icosahedral Cu-Au alloy particles depends on the composition of the Cu-Au alloy. On the basis of these results
it was deduced that the contraction of the surface lattice of the growing particles is responsible for the formation of icosahedral
and decahedral particles.
Received: 25 February 1997 / Accepted: 21 April 1997 相似文献
3.
定数截尾场合下Weibull分布的形状参数置信下限 总被引:1,自引:0,他引:1
为了求得双参数Weibull分布的形状参数m的单侧置信下限,通过构造统计量T1(m)=V/S1 V,推导出其分布与参数m、η无关,且其分位点计算简便.由此可得参数m的置信下限,且证明其为无偏.并通过大量的Monte-Carlo数值模拟试验证实了所给方法的可行性. 相似文献
4.
J.S. Ng H.Y. Liu M.J. Steer M. Hopkinson J.P.R. David 《Microelectronics Journal》2006,37(12):1468-1470
Photoluminescence measurements were carried out to investigate the origin of long wavelength emissions (1.6 μm at room temperature) observed from wafers with InAs quantum dots capped with GaAsSb layers. For wafers with high Sb content (22% and 26%) photoluminescence peak energies were found to be linearly proportional to third root of optical excitation power, a characteristic of emission due to a type-II band alignment. This work therefore presents unambiguous evidence that the long wavelength emission of the wafers comes from type-II band alignment between the InAs quantum dots and the GaAsSb capping layers. 相似文献
5.
Interactive vortex shedding in the multiply connected domain formed by a pair of circular cylinders is analysed by the FEM–FDM blending technique. The vorticity–streamfunction formulation is used to solve the incompressible Navier–Stokes equations at Re = 100, with the time-dependent wall streamfunctions determined from the pressure constraint condition and the far-field streamfunctions from the integral series formula developed earlier by the authors. The standard Galerkin finite element method is used in the relatively small FEM subdomain and the finite difference method based on the general co-ordinate system in the rest of the flow domain. Symmetric, antisymmetric and asymmetric wake patterns are obtained confirming the earlier experimental findings. The bistable nature of the asymmetric vortex shedding as well as the intermittent drifting from one status to the other between symmetric and antisymmetric wake patterns are reported. 相似文献
6.
We discuss the extension of radial SLE to multiply connected planar domains. First, we extend Loewner's theory of slit mappings to multiply connected domains by establishing the radial Komatu-Loewner equation, and show that a simple curve from the boundary to the bulk is encoded by a motion on moduli space and a motion on the boundary of the domain. Then, we show that the vector-field describing the motion of the moduli is Lipschitz. We explain why this implies that “consistent,” conformally invariant random simple curves are described by multidimensional diffusions, where one component is a motion on the boundary, and the other component is a motion on moduli space. We argue what the exact form of this diffusion is (up to a single real parameter κ) in order to model boundaries of percolation clusters. Finally, we show that this moduli diffusion leads to random non-self-crossing curves satisfying the locality property if and only if κ=6. 相似文献
7.
The formation mechanism for multiply charged ions (Cq+ and Oq+ (q = 2–4)) were investigated using a dual polarity time-of-flight mass spectrometer when diethyl ether clusters interacted with nanosecond laser pulse. The signal intensity of multiply charged ions and electron energy was measured experimentally. It was shown that the intensity of multiply charged ions increased about 50 times when laser intensity increased from 7.6 × 109 to 7.0 × 1010 W/cm2, then saturated as laser intensity increased further. It is interesting that the evolution of the mean value of electron energy was same to that of multiply charged ions. The theoretical calculation showed the ionization potential of atomic ions could be significantly decreased due to the effect of Coulomb screening especially at low laser intensity. It indicated that the electron ionization combined with Coulomb screening effect could explain the production of multiply charged ions in nanosecond laser field. 相似文献
8.
Enea Pagliano Claudio Broglia Miguel Molero Casado Francesco Malatesta 《Journal of solution chemistry》2008,37(10):1393-1409
Activity coefficients of the highly charged electrolytes Mgds, La2ds3, and [Co(en)3]2ds3 (en = ethylenediamine, ds2−=1,5-naphthalenedisulfonate anion), were determined at 298.15 K using liquid-membrane cells. These salts are found not to
display large negative deviations from the Debye-Hückel limiting slope in the dilute regions, which characterize the corresponding
sulfate salts. Theoretical calculations based on the primitive model (charged hard spheres in an unstructured dielectric medium)
reproduce the behavior of these salts correctly up to concentrations of 0.01 mol⋅kg−1 or more (0.1 mol⋅kg−1 for Mgds), although ds2−, far from resembling a charged sphere, is a planar ion with charges distant from one another. The Pitzer model parameter
values are reported for the activity and osmotic coefficients. 相似文献
9.
E.H. Brandt G.P. Mikitik E. Zeldov 《Physica C: Superconductivity and its Applications》2010,470(19):782-785
Recent experiments [O.M. Auslaender et al., Nat. Phys. 5 (2009) 35] use a magnetic force microscope not only to image but also to move and deform an individual vortex line in a bulk YBCO type-II superconductor. The theory of this experiment is presented accounting for pinning and curving of the vortex and for the full three-dimensional anisotropy of pinning and of vortex line tension in this material. 相似文献
10.
We develop a field theoretical method which permits us to study the dynamics of interacting particles in disordered systems. In particular, making use of a Hartree-type approximation, we obtain a self-consistent system of equations for disorder averaged quantities. The method is first applied to a single particle on a rough surface. Then, we calculate the current-voltage (I-V) characteristics of a type-II superconductor in the flux flow regime. Finally, the structure of the steps is discussed which arise in the I-V-characteristics when a small ac field is superimposed on the constant voltage. These may serve as a probe for incipient melting of the vortex lattice. 相似文献