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2009年05月22日

【期刊论文】Three-dimensional unsteady convection in LiCaAlF6-Czochralski growth

曾忠， Zhong Zenga， b， *， Jingqiu Chena， Hiroshi Mizusekib， Tsuguo Fukudac， Yoshiyuki Kawazoeb

Journal of Crystal Growth 266(2004)81-87，-0001，（）：

-1年11月30日

By means of the finite volume method, the evolution of the three-dimensional unsteady convection with increasing crystal rotation is simulated numerically for LiCaAlF6 in a model of Czochralski crystal growth. The effect of Marangoni convection on the flow structure features is investigated, and the results indicate that ignoring Marangoni convection causes a large deviation.

A1.， Computer simulation， A1.， Convection， A1.， Fluid flows， A1.， Marangoni convection， A2.， Czochralski method， B1.， Fluoride single crystal

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2009年05月22日

【期刊论文】Three-dimensional oscillatory convection of LiCaAlF6 melts in Czochralski crystal growth

曾忠， Zhong Zenga， b， *， Jingqiu Chena， Hiroshi Mizusekib， Kiyoshi Shimamurab， c， Tsuguo Fukudab， d， Yoshiyuki Kawazoeb

Journal of Crystal Growth 252(2003)538-549，-0001，（）：

-1年11月30日

摘要

Three-dimensional (3D) unsteady mixed thermal buoyancy, Marangoni and forced convection of LiCaAlF6 (LiCAF) melts (Prandtl number PrE1.4) are investigated numerically for model set up typically for Czochralski crystal growth. With increasing crystal rotation rate, convection evolves from steady axisymmetric to three-dimensional oscillatory convection with varying spatio-temporal features. The details of the oscillatory convection structures are presented.

A1.， Computer simulation， A1.， Convection， A1.， Fluid flows， A1.， Marangoni convection， A2.， Czochralski method， B1.， Fluoride single crystal

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2009年05月22日

【期刊论文】Marangoni convection in model of floating zone under microgravity

曾忠， Z. Zenga， *， H. Mizusekia， K. Shimamuraa， K. Higashinob， T. Fukudaa， Y. Kawazoea

Journal of Crystal Growth 229(2001)601-604，-0001，（）：

-1年11月30日

摘要

Marangoni convection in a half-zone model, a simplification of the floating zone model, is steady and axisymmetric for Marangoni number Ma5Mac, but the azimuthal flow after instability (Ma>Mac) breaks the axial-symmetry, and m-foldsymmetry of the flow pattern is observed. The symmetry number m (azimuthal wave number) depends strongly on the aspect ratio, As (As=height/radius), of the half-zone. Based on the results of numerical simulation, the nature of the correlation between m and As is investigated.

A1.， Convection， A1.， Fluidflows， A1.， Heat transfer， A2.， Floating zone technique

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2009年05月22日

【期刊论文】NUMERICAL SIMULATION OF CONVECTION DEPTH IN SHEAR CELL UNDER MICROGRAVITY

曾忠， Z. Zeng， H. Mizuseki， K. Ichinoseki， K. Higashino， and Y. Kawazoe

Adv. Space Rex Vol. 24, No.10, pp. 1321-1324, 199，-0001，（）：

-1年11月30日

摘要

By applying the idea of an isotope trace experiment, the concept of isotope trace in hydrodynamics simulation is proposed. The isotope concentration is conceived as a numerical marker to trace the convection and estimate numerically the convection depth due to shearing in shear cell under microgravity. Two different shearing rates, 2mm/s and 20mm/s, are investigated, and results demonstrate that the isotope depths are same for both cases at the termination of shearing, but the effect of residual flow field after shearing is different.

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2009年05月22日

【期刊论文】CAN 5d TRANSITION-METAL MONOLAYERS BE MAGNETIC ON FERROMAGNETIC SUBSTRATE?

曾忠， Q. Sun， a， b Q. Wang， a J.Z. Yu， a z. Zen， a Z.Q. Li， a K. Ohnoa and Y. Kawazoea

Solid State Communications, Vol. 106, No.10, pp. 665-667, 1998，-0001，（）：

-1年11月30日

摘要

The magnetic properties of X/5Fe/X (X: Hf, Ta, W, Re, Os, Ir, Pt) have been studied by means of the full-potential linearized augmented-plane-wave method, in which the core states are treated fully relativistically and the valence states are treated semirelativistically and the generalized gradient approximations' (GCA) exchange-correlation potentials are employed for 5d elements. It has been found that Hf, Ta, W, Re and Os overlayers on Fe(0 0 1) are almost nonmagnetic. Following this trend, if the spin-orbit interactions are taken into account, the magnetism of Ir and Pt overlayers is expected to be killed as for the Ag(0 0 1) and Au(0 0 1) substrate. So the nonexistence of the magnetism for 5d overlayers is furtherly verified on ferromagnetic substrate besides on nonmagnetic substrate. Moreover, due to the more extended 5d orbitals as compared to those of 3d and 4d, much stronger hybridizations between the 5d states of the overlayer and the Fe substrate exist, which greatly suppress the magnetic moment of the interface Fe layer.

A.， magnetic films and multilayers,， A.， surfaces and interfaces.，

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