Browsing by Author "Hsu, Y. C."

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Excited Energy Attenuation Study Through Vibration Measurement and Spectrum Analysis
(2010)
Lin, S. Y.
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Chang, C. K.
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Chung, C. T.
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Hsu, F. C.
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Wang, C. C.
This paper presents the use of vibration measurement in conjunction with spectrum signal analysis to investigate the vibration phenomena and the dynamic response of the absorber system frame and rigid axle of a vehicle body under real road-driving conditions. Ford 1.6L sedan was selected as the vehicle body to carry out the experiments with different driving speeds. B&K PULSE dynamic signal analyzer was used to detect the vibration signal induced from the absorber system frame and rigid axle of the vehicle body in motion. The acquired on-line signals are then processed through the Fast Fourier Transform using the power spectrum density, the cepstrum method, and the overall analysis. The vibration energy attenuated from the absorber system is analyzed by comparing with that on the rigid axle excited from the road conditions corresponding to different driving speeds. Furthermore, the effects of various road conditions and driving speeds on oscillation of the vehicle body are studied. The corresponding results may be extensively treated as a guiding reference of the absorber system design and manufacturing for those vehicle manufacturing companies.
Extreme Hyperlactatemia After Heart Transplantation: One Center's Experience
(2015-07-01)
Hsu, Y. C.
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Hsu, C. H.
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Huang, G. S.
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Lu, C. C.
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Wu, Z. F.
Introduction. Hyperlactatemia may occur early after cardiac surgery and is correlated with prognosis. This study was conducted to analyze the perioperative variables and postoperative outcomes among heart transplant recipients with extremely high lactate levels (>15 mmol/L). Methods. The single-center medical records of heart transplantation from June 2006 to May 2013 were retrospectively reviewed for patient characteristics, perioperative hemodynamic variables, arterial blood gas analysis data, and postoperative mortality. Results. Among 58 consecutive heart transplant recipients, lactate levels over the detectable upper limit (>15 mmol/L) were identified in 12 patients after intensive care unit admission, with peak time at 1.9 +/- 2.0 (range 0-6.1) hours. The maximal preoperative lactate level was 3.1 mmol/L, and most (11/12) postoperative lactate levels returned to <4 mmol/L at 27.5 +/- 12.8 hours after surgery (range 15-58, median 24), displaying a trend toward delayed extubation time in 10 recipients (P < .01). Blood glucose levels elevated significantly from preoperative 148.9 +/- 45.2 to 375.7 +/- 96.9 mg/dL at peak lactate level (P < .01). Four patients died in the ICU (range 5-32 days), 4 died after discharge (range 5-57 months), with 6 in total surviving over 1 year. Conclusion. Extreme hyperlactatemia commonly occurred early after heart transplantation and mostly recovered within 30 hours; however, with delayed extubation time after operation.
Study of electromigration in eutectic SnPb solder stripes using the edge displacement method
(2006-08-01)
Chou, C. K.
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Hsu, Y. C.
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Chen, Chih
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材料科學與工程學系
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Department of Materials Science and Engineering
Electromigration (EM) parameters in the eutectic SnPb solder were measured using the edge displacement method (EDM) and an atomic force microscope (AFM) in the temperature range of 60 degrees to 140 degrees C. The measured drift velocity was found to be 0.3 A/sec when the solder stripe was stressed under 4.9 x 104 A/cm(2) at 80 degrees C, and it increased as the current density or the temperature increased. The products of DZ* at 60 degrees C, 80 degrees C, 100 degrees C, 120 degrees C, and 140 degrees C were also obtained. In addition, the EM activation energy was determined to be 0.45 eV at the temperature range 60-100 degrees C and 0.55 eV at the temperature range 100-140 degrees C. These two activation energies may correspond to the Sn and Pb diffusion at the two temperature ranges. These values are very fundamental to current-carrying capability and mean-time-to-failure measurement for solder joints.