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1.
Fastconvergentstudyonpotential-harmonicmethodofdirectlysolvingSchrodingerequationinfew-bodysystemsWangYi-Xuan(王沂轩)andDensCong...  相似文献   
2.
正交曲线坐标下三维代数应力通量模型   总被引:7,自引:1,他引:6  
针对弯曲及不规则明渠的水动力及物质输运特性,本文建立了曲线坐标系下的三维代数应力通量数学模型,对平面上弯曲及不规则复杂边界情形,采用Poisson方程进行正交曲线坐标变换,各向异性的湍流代数应力通量模型被引用于本文的模拟计算中,以体现复杂边界条件引起的水动力及物质输运特性的变化。通过180度强弯曲明渠水槽及贵溪电厂不规则边界河段物理模型试验两个实例计算表明,实测值与计算吻合良好,效果令人满意。  相似文献   
3.
In this paper we propose a new protocol called time-space label switching protocol (TSL-SP) in optical burst switching (OBS), and define the terms time-space label (TSL) and time-space routing (TSR). An important concept of response time is introduced in the time label mechanism. The TSL-SP is a new technology that can quickly and efficiently forward data with a label on the optical networks. A two-dimension label switched path (TD-LSP) can be set up, that is maintained and deleted by the TSL-SP. For clearly illuminating the operation principles of the TSL-SP, we propose a new approach of orthogonal time-space coordinates in which the vertical coordinate is the space label and the horizontal coordinate is the time label. The proposed TD-LSP can dramatically reduce the routing failure probability and greatly improve the link network efficiency compared with other signaling protocols. Moreover, we define the time-space label control plane that can achieve the higher efficiency. When the TSL-SP is applied to networks, switching performance can be improved by two orders compared to the switching performance with the conventional OBS signaling protocols. The fundamental goal of TSL-SP is to band the signaling and routing functions together closely. Also, the TSL-SP can reduce the complexity of the network, support automatic service offering, and provide traffic engineering.  相似文献   
4.
Asymptotic solutions are presented for diffusion-controlled wet-chemical etching through a round hole in a mask. The three-dimensional diffusion field is assumed to be axisymmetric and fully developed. Two time regimes are considered. The first applies when the etched depth is small in comparison with the width of the mask opening. In the second, the depth of etching is much greater than the width of the mask opening. Explicit solutions are found for the shape of the etched surface as a function of the physical parameters. Among other things it is found that, as long as the etched pits are shallow, etching through small apertures is faster than through larger ones. The opposite is true for deep pits.  相似文献   
5.
We investigate the applicability of curvilinear grids in the context of astrophysical simulations and WENO schemes. With the non-smooth mapping functions from Calhoun et al. (2008), we can tackle many astrophysical problems which were out of scope with the standard grids in numerical astrophysics. We describe the difficulties occurring when implementing curvilinear coordinates into our WENO code, and how we overcome them. We illustrate the theoretical results with numerical data. The WENO finite difference scheme works only for high Mach number flows and smooth mapping functions, whereas the finite volume scheme gives accurate results even for low Mach number flows and on non-smooth grids.  相似文献   
6.
Stokes' second problem, the propagation and damping of waves into a semi-infinite fluid generated by harmonic oscillations of a flat pate on the surface, is solved for the simple Bingham Theological constitutive model. The solution reveals the existence of “windows” in the distance-time-stress space in which shearing is possible whereas outside these restricted regions no shearing can occur. Within these restricted regions the wave forms developed are exponentially damped, traveling waves which propagate from the excitation plane into the fluid and disappear along definitely prescribed boundaries determined by the yield condition. The most significant consequence of the existence of these “windows” of shear is that even very small yield stresses will radically modify the induced velocity wave patterns from that which would be expected based upon the classical Newtonian fluid solution of Stokes' second problem. At least in this physical setting, it is not necessary for shear to occur globally for motion to occur anywhere, as has been postulated in some recent studies of complex motions. Thus, the motion is consistent with a simple Bingham model which does possess a yield stress.  相似文献   
7.
邬晟峰  吴悦  徐拾义 《计算机科学》2014,41(5):50-54,63
对超大规模集成电路进行随机测试的测试码之间的距离作了定量分析,在此基础上,改进了最大距离随机测试算法中测试码的生成方法,使得所生成的伪随机测试码集合同时达到最大海明距离与近似最大笛卡尔距离。因此每一个测试码可以尽可能多地独立检测到更多不重复的故障。进而提出了准完全最大距离测试新算法的思想和构建理论,并详细阐述了该算法的执行流程。在ISCAS'85基准电路上进行的大量实验数据分析表明,本方法确实有效地提高了随机测试效率,降低了随机测试成本。  相似文献   
8.
Four polynomial expressions are obtained that provide a good approximation and an easy, rapid calculation of the chromatic coordinates and the chroma—L *, a *, b *, and C—for the illuminant C and the standard observer, for a virgin or extra virgin olive oil; absorbance is measured at only 480 and 670 nm. These are as follows: L *=0.556458(A480)2−2.51145A480+0.55504(A670)2−8.53016A670+98.4089; a *=0.177372(A480)2+2.1363A480+1.43254(A670)2−0.789231A670−13.9246; b *=−16.0277(A480)2+79.8932A480−5.06558(A670)2+3.36169A670+31.9405; C=−15.8439(A480)2+78.9312A480−5.26784(A670)2+3.56917A670+33.3927. These give acceptable results, making the method a practical alternative to the extremely laborious Commission Internationale d’Eclairage (CIE) L * a * b * system, by which 391 absorbance values must be measured individually, nanometer by nanometer, before applying more complex equations. The validity of the proposed method has been confirmed by comparison, using a set of 20 sample oils different from the set of 25 oils used to generate the order of the equations. The variations between the values provided by the proposed and standard methods, respectively, had a mean of 0.00 for each of the chromatic variables—L * , a * , b * , and C; SD were moderate (0.71, 0.52, 1.22, and 1.22, respectively); the root mean square and the R 2-terms also confirmed the validity of the method.  相似文献   
9.
介绍了电路板雕刻机的运动控制系统的特点和规律,系统以3关节直角坐标型机器人为外部结构,基于Visval C++的操做环境,控制核心采用DSP,同时与上位PC机通讯进行控制.对电路板雕刻机中的步进电机实现电气控制,以完成电路板的雕刻过程.  相似文献   
10.
椭圆曲线标量乘法运算是椭圆曲线密码(ECC)体制中最主要的计算过程,标量乘法的效率和安全性一直是研究的热点。针对椭圆曲线标量乘运算计算量大且易受功耗分析攻击的问题,提出了一种抗功耗分析攻击的快速滑动窗口算法,在雅可比和仿射混合坐标系下采用有符号滑动窗口算法实现椭圆曲线标量乘计算,并采用随机化密钥方法抵抗功耗分析攻击。与二进制展开法、密钥分解法相比的结果表明,新设计的有符号滑动窗口标量乘算法计算效率、抗攻击性能有明显提高。  相似文献   
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