Browsing by Author "LEE, TL"

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3-DIMENSIONAL NATURAL-CONVECTION OF AIR IN AN INCLINED CUBIC CAVITY
(1995-06-01)
LEE, TL
;
LIN, TF
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機械工程學系
;
Department of Mechanical Engineering
Three-dimensional steady and transient natural convective flow in a differentially heated inclined cubic cavity of air was numerically simulated by the projection method combined with the power law scheme. Various three-dimensional flow structures were induced, depending on the Reyleigh number and inclined angle, although the main flow is nearly two-dimensional. It is of interest to note that the flow is stronger when a vertical cavity is inclined, implying significant flow acceleration by the buoyancy component normal to the hot and cold walls. Change in the flow structure during the transient causes wavy variation of the space-averaged Nusselt number with time.
DIRECT OBSERVATION OF SI DELTA-DOPED GAAS BY TRANSMISSION ELECTRON-MICROSCOPY
(1992-05-25)
LIU, DG
;
FAN, JC
;
LEE, CP
;
TSAI, CM
;
CHANG, KH
Direct observation of the Si delta-doped layer in GaAs has been achieved by high resolution transmission electron microscopy. Samples with different Si doses, from half a monolayer to two monolayers, were studied. The observed spreading of the delta-doped layer showed that Si atoms are largely confined in five monolayers at most (in the highest dose case), indicating excellent confinements of dopants in GaAs. From the images, the Si atoms were uniformly distributed in the doped layer, no cluster formation was observed. For delta-doped GaAs grown at low temperature (480-degrees-C), stacking faults originated from the doped layers were observed. These faults were thought to be caused by the large unrelaxed strain in the low-temperature grown GaAs.
INVESTIGATION ON THE INTERFACE OF THE POLYCRYSTALLINE SILICON CONTACTED DIODE FORMED WITH A STACKED AMORPHOUS-SILICON FILM
(1992-08-01)
WU, SL
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LEE, CL
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LEI, TF
;
LEE, TL
;
CHEN, LJ
The structural morphology of the poly-single crystalline silicon interface of a diode formed with a stacked-amorphous-silicon (SAS) film has been investigated. Secondary ion mass spectroscopy analyses showed the existence of multi-dopant segregation peaks at each layer boundary and at the poly-single crystalline silicon interface. The break-up at the poly-single silicon interface and the epitaxial regrowth of the polysilicon realigned to the silicon substrate were found to depend not only on the polysilicon deposition and the post annealing conditions, but also on the number and the thickness of the stacked amorphous silicon layers. For the diode formed with a six-layer stacked amorphous silicon, break-up of the interface was found to occur even at an annealing temperature as low as 900-degrees-C. After an additional annealing at 1000-degrees-C for 20 min, the interface was fully broken-up and the epitaxial regrowth layer of the polysilicon could be as thick as 760 angstrom.
NANOMETER THICK SI/SIGE STRAINED-LAYER SUPERLATTICES GROWN BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION TECHNIQUE
(1994-04-01)
CHANG, TC
;
CHANG, CY
;
JUNG, TG
;
TSAI, WC
;
WANG, PJ
High quality Si/Si1-xGex superlattices having layers as thin as 1.5 nm have been grown by an ultrahigh vacuum/chemical vapor deposition system. High-resolution double-crystal x-ray diffraction, and conventional and high-resolution cross-sectional transmission electron microscopy were used to evaluate the crystalline quality of these superlattices. A dynamical x-ray simulation program was employed to analyze the experimental rocking curves. Excellent matches between experimental rocking curves and simulated ones were obtained for all superlattices with various periodicity. A cross-sectional transmission electron micrograph of an 80 period Si(4.2 nm)/Si0.878Ge0.122 (1.5 nm) superlattice, in which each individual layers was clearly resolved, demonstrated the capability of this growth technique for nanometer thick layer deposition.
STEADY CONJUGATE HEAT-TRANSFER IN TURBULENT CHANNEL FLOWS
(1990)
YAN, WM
;
FIN, TF
;
LEE, TL
;
機械工程學系
;
Department of Mechanical Engineering
TRANSIENT OSCILLATORY CONJUGATE NATURAL-CONVECTION IN A TALL WATER CAVITY
(1993-12-01)
LEE, TL
;
LIN, TF
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A two-dimensional numerical simulation was conducted to investigate the effects of the heat capacity of the heated wall on the transient oscillatory convection in a tall cavity. Results were particularly obtained for water (Pr = 6) in a tall cavity (A = 6) with constant-heat-flux heating on one side and isothermal cooling on the opposing side. Significant wall heat capacity effects were found. Specifically, a heated wall of finite heat capacity can slow down the flow evolution process to steady state at low Rayleigh number and damp the flow oscillation during the initial developing period at high Rayleigh number. In periodic flow at Ra(H)* = 4.4 x 10(10) the wall heat capacity significantly reduces the amplitude of the temperature oscillation. A quasi-periodic flow at Ra(H)* = 4.8 x 10(10) was found to become periodic when the wall heat capacity was included. The wall heat capacity does not shown noticeable effect when the flow is chaotic for Ra(H)* = 6.0 x 10(10).