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428 results on '"Lee, H.T."'

242. Adhesive strength and tensile fracture of Ni particle enhanced Sn–Ag composite solder joints

Author

Lee, H.T. and Lee, Y.H.

Subjects
*FILLER metal, *SEALING (Technology), *SOLDER & soldering, *WELDING, *COMPOSITE materials
Abstract

Abstract: This study forms composite solders by adding 0.5–3wt% of Ni particles in situ to Sn–3.5wt%Ag lead-free solder. Cu/solder/Cu specimens are prepared by dipping two Cu rods into a solder bath to produce a solder joint. Some of the joint specimens are retained in the as-soldered condition, while the others are aged at 150°C for 100, 200, 400, or 500h, respectively. The experimental results reveal that the addition of Ni to the molten Sn–Ag solder leads to the formation of in situ Ni3Sn4 dispersoids. The adhesive strength of the joint is found to increase with increasing Ni content in the as-soldered specimens. In general, the strength of the thermally processed specimens reduces as the thermal storage time increases. The Sn–Ag–0.5wt%Ni joints show a mixture of ductile and brittle fracture, whereas the joints containing more than 1wt% of Ni show mainly brittle fracture with solder residue at the exposed (Cu,Ni)6Sn5 IMC layer. [Copyright &y& Elsevier]

Published
2006
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243. Differences in embryonic development in sensitive and resistant matings to pregnancy block stimuli in mice.

Author

Chung, H.J., Pak, J.K., Kim, B.K., Lee, Y.K., Im, S.K., Seong, H.H., Uhm, S.J., Lee, H.T., Chung, K.S., Min, K.S., Kim, J.H., Wakasugi, N., and Wang, W.K.

Subjects
EMBRYOS, PREGNANCY, BROMOCRIPTINE, LABORATORY mice
Abstract

Investigates how development of BALB/cA and F1 embryos differ under the influence of pregnancy block stimuli in mice. Histological observation after bromocriptine treatment; Detachment of the inner cell mass; Lining of the inner surface of trophoblast by distal endoderm layer.

Published
2003
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244. Charge-coupled device observations of the open cluster NGC 6823 and associated bright nebula NGC 6820: first results and prospects of the Uzbek-Taiwan collaboration at Maidanak.

Author

Hojaev, A.S., Chen, W.P., and Lee, H.T.

Subjects
STARS, TELESCOPES, OPEN clusters of stars, SPACE sciences
Abstract

Preliminary results of broad-band and narrow-band charge-coupled device imaging of the young star cluster NGC 6823 and the associated bright nebula NGC 6820 are reported. The observations were made in August 2001 at Maidanak Observatory (Uzbekistan) as a collaborative initiative between the Graduate Institute of Astronomy, National Central University, Taiwan, and Ulugh Beg Astronomical Institute, Uzbek Academy of Sciences. The two institutes, together with colleagues from Lithuania and Latvia, are working together to modernize and instrument the existing telescope facilities at Maidanak to make use of the excellent astroclimate of the site. As a pilot project, we selected candidate young stars in NGC 6823, based on their 2MASS near-infrared colours and obtained their photometry with Maidanak telescopes. The youth natures of some of these sources were later confirmed by spectra taken by the 2.16 m telescope at Beijing Observatory. This demonstrates that combination of small telescopes and existing databases, such as 2MASS, ROSAT or Chandra, can yield fruitful science. Other Uzbek-Taiwan collaborations are being planned. [ABSTRACT FROM AUTHOR]

Published
2003
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245. Using C index with fuzzy numbers to evaluate service quality.

Author

Lee, H.T. and Chen, S.H.

Subjects
QUALITY of service, FUZZY sets
Abstract

Introduces the concept of process capability index that considers both the average and the consistency of the data simultaneously in evaluating service quality. Use of fuzzy numbers of linguistic variables developed in fuzzy set theory to modify the process capability index; Use of the index to help point out the direction for improving service quality.

Published
2002
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246. Adenosine attenuates oxidant injury in human proximal tubular cells via A[sub 1] and A[sub 2a] adenosine receptors.

Author

Lee, H.T. and Emala, Charles W.

Subjects
*ADENOSINES, *KIDNEY tubules, *CELL death
Abstract

Determines the signaling pathways of adenosine receptor-mediated protection against oxidant energy in human proximal tubule (HK-2) cells. Measurement of HK-2 cell death; Location of proximal tubules in the outer medulla of the kidney; Activation of the cAMP response element binding protein.

Published
2002
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248. Oxidant Preconditioning Protects Human Proximal Tubular Cells against Lethal Oxidant Injury via p38 MAPK and Heme Oxygenase-1

Author

Lee, H.T., Xu, H., Ota-Setlik, A., and Emala, C.W.

Abstract

AbstractIschemic preconditioning protects the kidney from subsequent ischemic injury but the signal transduction pathways involved are unknown. Human proximal tubular (HK-2) cells were protected from injury with 2.5 mM H2O2 by preconditioning with a single 15-min exposure to 500 μM H2O2 followed by 16 h of recovery (oxidant preconditioning). To identify the signaling pathways involved in oxidant preconditioning, we utilized inhibitors of several signaling intermediates (MAPK/ERK kinase I, p38 mitogen-activated protein kinase (MAPK), protein kinase C and tyrosine kinase). A rapid but transient increase in p38 MAPK was observed following oxidant preconditioning and an inhibitor of p38 MAPK (SB203580) abolished the protection provided by oxidant preconditioning. Oxidant preconditioning was also associated with heat shock protein-27 phosphorylation (by p38 MAPK) and an increased synthesis of heme oxygenease-1 (HO-1). Stimulation or inhibition of HO-1 with hemin or Zn(II) protoporphyrin IX, respectively, mimicked or abolished oxidant preconditioning-mediated cytoprotection. Inhibitors of new protein synthesis (cycloheximide) and gene transcription (actinomycin D) also blocked the cytoprotection by oxidant preconditioning. We conclude that oxidant preconditioning protects HK-2 cells against more severe oxidant injury via activation of signaling pathways that include p38 MAPK and increased synthesis of HO-1.Copyright © 2003 S. Karger AG, Basel

Published
2003

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