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991.
992.
The present work is aimed to study mixed convection heat transfer characteristics for a lid-driven air flow within a square enclosure having a circular body. Flows are driven by the left lid, which slides in its own plane constant velocity. This wall is isothermal and it moves up or down in y direction while the other walls remain stationary. The horizontal walls are adiabatic. The cavity is differentially heated and the left wall is maintained at a higher temperature than the right wall. Three different temperature boundary conditions were applied for the inner cylinder as adiabatic, isothermal or conductive. The computation is carried out for wide ranges of Richardson numbers, diameter of inner cylinder and center and location of the inner cylinder. It was found that the most effective parameter on flow field and temperature distribution is the orientation of the moving lid. The circular body can be a control parameter for heat and fluid flow. An interesting obtained result that the thermal conductivity becomes insignificant for small values of diameter of the circular body. 相似文献
993.
A set of four quaternion matrices is used to represent the equations of finite rotation theory and to describe the kinematics
and nonlinear dynamics of an asymmetric rigid body in space. The results obtained are tested in setting up direction-cosine
matrices, calculating three-index symbols, establishing the relationship between the components of angular velocity in body-fixed
and space-fixed frames of reference, and using a set of three independent rotations. Euler–Lagrange equations and a set of
four quaternion matrices are used to construct a block-matrix model describing the nonlinear dynamics of a free asymmetric
rigid body in three-dimensional space. The model gives the matrix Euler’s equations of motion and other special cases. Algorithms
adapted to use in a numerical experiment are developed
Translated from Prikladnaya Mekhanika, Vol. 45, No. 2, pp. 133–143, February 2009. 相似文献
994.
995.
Jakub Kedzierski Peiqi Xuan Vivek Subramanian Jeffrey Bokor Tsu-Jae King Chenming Hu Erik Anderson 《Superlattices and Microstructures》2000,28(5-6)
As the scaling of CMOS transistors extends to the sub-20 nm regime, the most challenging aspect of device design is the control of the off-state current. The traditional methods for controlling leakage current via the substrate doping profile will be difficult to implement at these dimensions. A promising method for controlling leakage in sub-20 nm transistors is the reduction in source-to-drain leakage paths through the use of a body region which is significantly thinner then the gate length, with either a single or a double gate. In this paper we present ultra-thin body PMOS transistors with gate lengths down to 20 nm fabricated using a low-barrier silicide as the source and drain. Calixarene-based electron-beam lithography was used to define critical device dimensions. These transistors show 260 μ A μ m − 1on-current and on/off current ratios of 106, for a conservative oxide thickness of 40 Å and | Vg − Vt| = 1.2 V. Excellent short-channel effect, with only 0.2 V reduction in | Vt| is obtained in devices with gate lengths ranging from 100 to 20 nm. 相似文献
996.
用多体微扰理论和原子体系图示法,研究和讨论了钠原子双激发 [2p,3s]→[4p,kl(kp+kf)]并计算了钠原子的光电离激发截面,计算结果与实验结 果相符。 相似文献
997.
用多体微扰理论和原子体系图示法,研究和讨论了钠原子双激发[2p, 3s]→[5s,kl (ks+kd)]并计算了钠原子的光电离激发截面,计算结果与实验结果相符 。 相似文献
998.
999.
IntroductionAnelastomer(compressibleorincompressible)betweentwoparallelrigidsurfacesisakindofoftenworkinengineeringandtechnology.Thestudyforitsdeformationundertheroleofforcebeganmanyyearsago.Targetstudied—bondedelasticbodyisdividedintoacircularcylindri… 相似文献
1000.
利用碰撞弹簧概念,结合多柔体系统动力学方法,建立了多体系附落碰撞的动力学模型。并通过求出响应,可详细描述碰撞过程。 相似文献