• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.196-197
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• 2006

In this study, low temperature sintering multilayer piezoelectric transformer for DC-DC converter were manufactured using (PbCaSr)Ti(MnSb)$O_3$ ceramics and thin their electrical properties were investigated according to the vanation of frequency and load resistance. The voltage step-up ratio of multilayer piezoelectric transformer showed the maximum value m the vicinity of 1.3MHz and increased according to the increase of load resistance. When the output impedance coincided with the load resistance, the piezoelectric transformer showed the temperature rise of about $21^{\circ}C$ under the output power of 6W.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.188-192
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• 2000

An analysjs model for calculation the motion accuarcy of double sides hydrostatic table is proposed in thn paper. For the analysis of motion accuracy, profiles of each rails are assumed as periodic function, and represented using Fourier coefficients. Variahon of bearing clearance is represented as the vanation of linear, angular displacement of table and profiles of rails. Motion accuracy is calculated in the basis of finite element analysis on the pressure dutributmn of table. In order to improve calculating time in the analysis of motion accuracy, The proposed modeling method converts double sides table to single side table equivalently Results by the proposed method 1s compared with directly caculated results mdyhcally, and also compared wlth experimental results. From the theoretical and experimental analysis, it is confirmed that the proposed modeling mothod is very effective to analyze the motion accuracy of dauble sides hydrostatic table.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.43-46
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• 2000

Optical triangulation displacement sensors(0TDSs) are widely used for their simple struchlre, high resolution, and long operating range. However, there are several factors that must be taken into account in order to obtain high accuracy and reliability Measurement errors from inclinations a？ an object surface, prohe signal fluctuations generated by speckle effects. power vanation of a light source, electronic noises, and so on. Previous models of OTDSs can not show reasonable behavior as change of surface inclination and shape of light intensity distribution on the detector. In this paper, we propose a new and reasonable modeling for diffise-type OTDSs based on a geometrical optics. To verify propriety of new modeling, we take basic experiments. Shape of light intensity distribution is asymmetric in both simulation result and experimental result. Both simulation result and experimental result show same tendency of light intensity distribution movement as changing surface inclination

• KSBB Journal
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• v.9 no.2
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• pp.186-190
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• 1994

The content of taxol and related compounds in various tissues of native yews( T. cuspidata var. latifolia) grown in 5 locations of Ullung Island were analyzed. A considerable range of vanation in the content was observed in the needle and bark collected from different trees located at the same area as well as at five different areas. Taxol content was much higher in the needle(0.017% on the dry weight basis) than those in the bark, whereas the content of 10-deacetyl baccatin III(10-DAB III) was slightly higher in the bark(0.073%), regardless of the location of the trees collected. Particuayly, the needle collected from the Hyunpo area, which located in North-west part of Ullung Island, contained the highest level of taxol(0.024%) exceeding the reported level in dried barks of Pacific yew and also somewhat higher level of its Precusor, 10-DAB III(0.049%). These results suggested that the needle of the yew at the Ullung Island could be suitable materials as a renewable source for the mass production of taxol.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.242-247
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• 1989

This study was conducted to estimate the inheritance of allozyme variants in IDH, ME and PGI, using megagametophyte tissue of seeds of Pinus densiflora and Pinus thunbergii in Kyungpook province. Two alleles at a single locus were detected for MH in Pinus densiflora, but Pinus thunbergii showed no varition, showing only one band. Four alleles at one locus were determined for ME in Pinus densiflora and Pinus thunbergii. Two loci were found for PGI and no variation seemed to occurred in A-locus as the presence of one single band. Five alleles were presented in B-locus in Pinus densiflora, but two alleles $B_1$ and $B_2$ in Pinus thunbergii. In PGI, an allozyme composed of multiple bands is observed from haploid megagamtophyte tissues. The isozyme variants of IDH, ME and PGI were appeared to segregate into 1 : 1 ratio for all zones.