Browsing by Author "Pan, Y. W."

Now showing 1 - 3 of 3

Bearing behavior and failure mechanism of a shallow foundation located on/behind the crest of a poorly cemented artificial sandstone
(2008-12-01)
Chang, J. C.
;
Liao, J. J.
;
Pan, Y. W.
;
土木工程學系
;
Department of Civil Engineering
"Embedded Emitters": Direct bandgap Ge nanodots within SiO2
(2016-12-21)
Kuo, M. H.
;
Chou, S. K.
;
Pan, Y. W.
;
Lin, S. D.
;
George, T.
Microdisk-arrays of vertically stacked 30-70nm Ge nanodots embedded within SiO2 were fabricated using thermal oxidation of Si0.75Ge0.25 abacus-shaped pillars and followed by post-annealing in oxygen-deficient conditions. The Ge nanodots are subjected to increasing quantum-confinement and tensile-strain by reducing dot size. We show that considerable quantum-confinement and tensile-strain can be generated within 30 nm Ge nanodots embedded in SiO2, as evidenced by large Raman red shifts for the Ge-Ge phonon lines in comparison to that for bulk Ge. These large quantum-confinement and tensile-strain facilitate direct-bandgap photoluminescence experimentally observed for the Ge nanodots, and are consistent with the strain-split photoluminescence transitions to the light-hole (LH) and heavy-hole (HH) valence bands at 0.83 eV and 0.88 eV, respectively. Time-resolved photoluminescence measurements conducted from 10-100K show temperature-insensitive carrier lifetimes of 2.7 ns and 5 ns for the HH and LH valence-band transitions, respectively, providing additional strong evidence of direct bandgap photoluminescence for tensile-strained Ge nanodots. Published by AIP Publishing.
Site characterization for the investigation of tunnel 8 collapse
(2004)
Huang, A. -B.
;
Lin, C. P.
;
Liao, J. J.
;
Pan, Y. W.
;
Tinkler, J.
A section of the high speed rail tunnel collapsed before the installation of permanent lining. The section designated as Tunnel 8 was located in Miaoli County in Northern Taiwan. The resulting spoil blocked approximately 50 in of the tunnel. A crater of 28 in in diameter, with a maximum depth of 12.1 in was formed at the ground surface, at approximately 60 in above the crown level of the tunnel. A site characterization program was carried out to define the boundaries of the collapsed zone, provide ground water information and stress and stiffitess parameters for the outer and final concrete lining design. Six 100 in deep, rotary cored holes were drilled vertically from the ground surface, within the collapsed zone and penetrated through the tunnel level. SPT, pressuremeter and suspension P-S logging tests were performed in these boreholes. Seven open boreholes, approximately 60 in deep, were drilled laterally from the concrete barricade at north and south end of the collapse zone within the tunnel at various angles. Geophysical tests which included seismic refraction tomography and resistivity tests were conducted from the ground surface. The data collected from the site characterization coupled with the geological background were analyzed and an image of the possible disturbance zone was created. The paper describes details of the site characterization, their interpretation and results of the analysis.