Convectively driven flow past an infinite moving vertical cylinder with thermal and mass stratification

An analysis is performed to study the unsteady, incompressible, one-dimensional, free convective flow over an infinite moving vertical cylinder under combined buoyancy effects of heat and mass transfer with thermal and mass stratifications. Laplace transform technique is adopted for finding solutions for velocity, temperature and concentration with unit Prandtl and Schmidt numbers. Solutions of unsteady state for larger times are compared with the solutions of steady state. Velocity, temperature and concentration profiles are analysed for various sets of physical parameters. Skin friction, Nusselt number and Sherwood number are shown graphically. It has been found that the thermal as well as mass stratification affects the flow appreciably.     

高气压TE CO2激光泵浦的高功率连续可调谐远红外喇曼NH3激光器

本文报道输出能量约4mJ(功率约80kW)的连续可调谐远红外喇曼跃迁NH₃激光器,调谐范围约覆盖发射谱从90到93μm的70％。分立K能级激光跃迁的连续调谐范围约为30GHz。文中给出了典型的实验结果,并进行了讨论。 关键词：     

Ramanujan’s modular equations of degree 5

We provide alternative derivations of theta function identities associated with modular equations of degree 5. We then use the identities to derive the corresponding modular equations.     

Microstructure analysis of chemically synthesized wurtzite-type CdS nanocrystals

Microstructure of chemically synthesized wurtzite-type CdS nanocrystals have been investigated by X-ray diffraction (XRD) peak profile analysis by applying different forms of Williamson–Hall (WH) method viz., uniform deformation model (UDM), uniform stress deformation model (USDM) and uniform deformation energy density model (UDEDM), and transmission electron microscope (TEM) observations. The WH methods show the average crystallite size to be about 10 nm. Strain, stress and energy density of the nanocrystals are found to be 1.18 × 10 ^?2, 0.43 GPa and 2.27 kJ m ^?3, respectively. High-resolution TEM (HRTEM) results show the nanocrystals to be in spherical shape with an average crystallite size of 10 nm, thereby complementing the size estimation by WH methods. Further, HRTEM observations reveal the presence of edge dislocations and twin boundaries within the nanocrystals.