• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.519-522
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• 2002

Ag (silver) can be used for YBa$_2$Cu$_3$O$\_$7-$\delta$/(YBCO) coated conductor tape as the substrate on which YBCO can be deposited directly because of the chemical compatibility of Ag with YBCO. We have fabricated rolled Ag tapes with various total reduction ratios and different thicknesses. As-rolled Ag tape was recrystallized at 750$^{\circ}C$ for 30min in air and vacuum of 10$\^$-3/ torr. The orientation distribution functions (ODF) calculated from three x-ray pole figures of as-rolled and recrystallized tapes were analysed. As the total reduction ratio increased from 94 to 98%, the development of {110}texture of as-rolled Ag improved. Under the present experimental condition, maximum {110}ODF value of Ag tape was obtained for the sample with 94% total reduction ratio which was recrystallized at 750$^{\circ}C$ for 30min in vacuum of 10$\^$-3/ torr.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1184-1189
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• 1990

In order to investigate liquid fuel filming over the intake manifold wall, an electrode-type probe has been developed by lines of authors and this probe was employed in a single cylinder two and four-stroke cycle engine and in a four cylinder four-stroke engine operated by neat methanol fuel. The performance of the probe was dependent upon several parameters including the liquid fuel layer thickness, temperature, additive in the fuel, and electric power source (i.e., AC and voltage level) and was independent of other variables such as direction of liquid flow with respect to the probe arrangement. Several new findings from this study may be in order. The flow velocity of the fuel layer in the intake manifold of engine was about (if the air velocity in the steady state operation, the layer thickness of liquid fuel varied in both the circumferential and longitydinal directions. In the transient operation of the engine, the temporal variation of fuel thickness was determined, which clearly suggests that there was difference between fuel/air ratio in the intake manifold and that in the cylinder. The variation was greatly affected by the engine speed, fuel/air ratio and throttle opening. And the variation was also very significant from cylinder to cylinder and it was particularly strong different engine speeds and throttle opening.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.247-253
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• 2010

The characteristics of selective oxidation prior to hot-dip galvanizing with the annealing atmosphere dew point and chemical composition in dual-phase steels and their effect on the inhibition layer formation relevant to coating adhesion have been studied using a combination of electron microscopic and surface analytical techniques. The annealed and also galvanized samples of 3 kinds of Si/Mn ratios with varied amounts of Si addition were prepared by galvanizing simulator. The dew point was controlled at soaking temperature $800^{\circ}C$ in 15%$H_2$ -85%$N_2$ atmosphere. It was shown that good adhesion factors were mainly uniformity of oxide particle distribution of low number density and low Si/Mn ratio prior to hot-dip galvanizing. Their effect was the greatly reduced coating bare spots and the formation of uniform inhibition layer leading to good adhesion of Zn overlay. The mechanism of good adhesion is suggested by two processes: the formation of inhibition layer on the oxide free surface uncovered with no $SiO_2$-containing particles in particular, and the inhibition layer bridging of oxide particles. The growth of inhibition layer was enhanced markedly by the delayed reaction of Fe and Al with the increase of Si/Mn ratio.

• The Journal of Pediatrics of Korean Medicine
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• v.17 no.2
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• pp.37-53
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• 2003

Objective : To find risk factor and symptoms for transferred newborn from postpartum care center Method : We performed a follow-up study using medical record. Subjects comprised 188 neonates(include 4 twins) and 184 women in childbed who were hospitalized in oriental postpartum care center from January, 1, 2002 to December, 31, 2002. Result: Transferred newborn was total 24, N.V.D. 17, C.S. 7, male and female were 12 separately. The symptom of transfer was fever(16), diarrhea(4), jaundice(3), convulsion(1) Transferred number and rate was male 12(10.7%), female 12(15.8%). In delivery method, total normal vaginal delivery(N.V.D.) was 136 and transferred 17(12.5%), total cesarean section(C.S.) was 52 and transferred 7(13.5%). Transferred rank was N.V.D. female(17.9%). C.S. male(15.6%), C.S. female(10%), N.V.D.(8.6%). Of the 188 neonates. immature infants were 2 and transferred 1(50%), term infants were 184, transferred 23(12.5%), post-term infants were 2 and transferred none(0%). In age of women in childbed, transferred ratio was 15.4%(over 35), 15.2%(25-29), 10.5%(30-34). In fever,. C.S. infants were more transferred than N.V.D. and male infant had a tendency to transfer in later period of hospitalization and female in early period. It seems that transfer was related to abortion. In diarrhea, all was N.V.D. and their diagnosis was rotavirus. The average age of women in childbed was yonger(28.5). In jaundice, all was 1st, and average birth weight was lighter(3153g). The average age of women in childbed was older(30). In convulsion, birth weight was lighter(3153g), and age of women in childbed was older(30). Conclusion : There's any relation with sex and delivery method, birth weight and mother's age in transfer. But we cannot find any statistically significance. Further prospective studies are needed to find risk factors in transfer.

• Journal of The Korean Astronomical Society
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• v.34 no.1
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• pp.41-45
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• 2001

We tested the characteristics of the BOAO Medium Dispersion Spectrograph (MDS) such as the CCD capabilities, wavelength shift by gravity direction variation, slit illumination function and efficiency. Then we calculated the appropriate exposure time to obtain the given S/N ratio for several given magnitudes. Also the remaining problems to be improved were discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.243-248
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• 1993

New methodology for fiducial alignment is proposed to improve the alignment accuracy in wafer steppers. The positioning error is detected by PSD(Position Sensitive Detector)when 2-dimensional vernier patterns on a reticle on a reticle are projected on the fiducial marks of wafer stage. The width and period of vernier patterns are deter mined to get the highest S/N ratio for the exposure wavelength 248.4nm of KrF excimer laser. This new method has an advantage of higher accuracy and faster alignment over the conventional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.148-154
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• 1994

The dynamic analysis of S/N ratio in this study to improve EER has proven to be very effective. The optimized condition can improve EER during the developing process without increasing noise and any other investment. If this method is used widely to design valve systems of compressor for refrigeration and air-conditioning, output capacity will be greatly increased for industry.

• Structural Engineering and Mechanics
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• v.26 no.4
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• pp.393-408
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• 2007

The effects of material nonhomogeneity and nonisothermal conditions on the stress response of pressurized tubes are assessed by virtue of a computational model. The modulus of elasticity, the Poisson's ratio, the yield strength, and the coefficient of thermal expansion, are assumed to vary nonlinearly in the tube. A logarithmic temperature distribution within the tube is proposed. Under these conditions, it is shown that the stress states and the magnitudes of response variables are affected significantly by both the material nonhomogeneity and the existence of the radial temperature gradient.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1402-1404
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• 1987

Photoconductive target was fabricated to make vidicon available. In order for a vidicon to operate well, it is essential that the target have high photosensitivity, low image lag, and high resolution. In the vidicon mode analysis, photosensitivity of 0.8, image lag of 30%, resolution of 300 TV lines, and the S/N ratio of 30 dB at 10 lux illumination were measured.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.9
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• pp.1134-1140
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• 1988

In this paper, the theory of superresolution algorithms for estimation of directions of arrival of signals using eigen-structure analysis (mainly MUSIC algorithm)is described. Also, we apply MUSIC algorithm to circularly disposed antenna system, and simulate the angular resolution according to relative azimuth difference, S/N ratio, number of snapshots, so that we confirm the possibility of applications of MUSIC algorithm to sky wave in real situations.