• Journal of Powder Materials
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• v.6 no.2
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• pp.171-177
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• 1999

Ti-45.2at.%Ni-5at.%Cu and Ti-40.2at.%Ni-10atat.%Cu alloy powders were fabricated by gas atomization process. The microstructures, Shape, hardness and phase transformation behaviors of the powders were investigated by means of optical microscopy, scanning electron microscopy, micro-hardness measurement, x-ray diffraction analyses and differential scanning calorimetry. The hardness of the Ti-Ni-XCu alloy powders decreased as Cu-content increased. The x-ray diffraction analyses were carried out for powders without heat treatment, and those that treated at 85$0^{\circ}C$ for an hour in a vaccum state($10^5$ torr) and then quenched into ice water. The intensity of B$19^t$ phase increased with heat treating. The monoclinic B$19^t$ martensite was formed in the Ti-Ni-XCu alloy powders during cooling.

• Journal of the Korean Ceramic Society
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• v.11 no.4
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• pp.31-36
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• 1974

For gold balsam, the suitable sulfur balsam which is made of lavender oil and sulfur is found to be the distillate with the content of 15~19% sulfur. The sulfur balsam is distillated under 20mmHg vaccum at 84~105$^{\circ}C$. The composition of the compound which is produced by reaction between sulfur balsam and gold chloride is recognized as C10H18SAuCl3. This varys to C10H18SAuCl in water. The reaction constants K from C10H18SAuCl3 to C10H18SAuCl at 30, 40, 5$0^{\circ}C$ are as followsr. K1=7.97~9.28$\times$10-2 K2=2.81~3.79$\times$10-1 K3=4.74~6.74$\times$10-1 The plots of T versus log K are linear, which shows pseudo-first order reaction. The lower temperature is, the more stable C10H18SAuCl3 is. The gold balsam with excess sulfur balsam is increased in stability.

• Journal of the Korean Ceramic Society
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• v.31 no.3
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• pp.282-290
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• 1994

In this research, the organic salt [RCOOH] Br with long alkyl-chain was synthesized, and the organophilic [RCOOH]-Montmorillonite was formed by cation-exchange-reaction between Na-Montmorillonite and synthesized organic salt [RCOOH] Br. After drying of the organophilic [RCOOH]-Montmorillonite at $65^{\circ}C$ in high vaccum, the experiments for the probability of forming its complexes with various swelling-solutions as dist, water, methanol, ethanol, acetonitrile, propionitrile, butyronitrile, toluene and n-decanol were performed, and the corresponding basal spacings obtained were 17.44$\AA$, 31.86$\AA$, 34.38$\AA$, 30.37$\AA$, 32.39$\AA$, 35.04$\AA$, 14.16$\AA$ and 14.63$\AA$ respectively.

• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.26-35
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• 1997

Rigorous coupled-wave analysis (RCWA) with a simplified eigenvalue problem is used to investigate the an-tireflective property of one-dimensional surface-relief gratings such as binary gratings, triangular gratings and gratings with triangle-like surface profiles. The convergence of RCWA is investigated by varying the number of layers and the number of space-harmonics used in the computation. For unpolarized light normally incident on a medium of refractive index 1.64 from vaccum, a triangle-like grating shows the reflectivity of $1.6 {\times} 10^{-4}$ in contrast to a minimum reflectivity of $3.8 {\times} 10^{-3}$ for a binary grating. We also study the dependence of reflectivity on the wavelength, and on the angle of incidence for a groove shape and depth which result in minimum reflectivity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.944-947
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• 1997

Docosahexaenoic acid (DHA) rich oil was obtained from blue fin tuna (Thunnus thynnus orientalis) orbital tissue with centrifugation of 12,000 rpm under vaccum $(10^{-1}\;Torr)\;at\;4^{\circ}C$. The effect of DHA rich oil (DHA content; $27.8\%$) on $CCl_4-induced$ acute injury was investigated biochemically and histopathologically. Dosage of DHA rich oil on 24h before $ CCl_4-administration$ prevented significantly the increase of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GTP) values. No necrosis of hepatocytes was observed in rat livers treated with DHA oil on 24h prior to $CCl_4-administration$. These results suggested that DHA oil controls the accumulation of fat in the liver and prevented the liver injury.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.524-526
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• 2007

Polymer dispersed liquid crystal (PDLC) films consist of micro-droplets of liquid crystals dispersed in a polymer matrix. To make wide area PDLC filled devices, it is necessary to develop reliable method of vacuum injection of PDLC solution instead of the capillary injection. However, well-known 2-ethylhexylacrylate (EHA), main element of a prepolymer, exhibits the volatility problems, when the PDLC solution is placed under the low pressure. In this study, we developed the vacuum injection process to fill a wide area cell. Experimental results indicate that the $V_{90}$(turn-on voltage) of the PDLC cell made by a vacuum injection method are lower than that of the PDLC cell made by a capillary injection method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.9-15
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• 2003

This Paper deals with the design of Moving Magnet type Linear Oscillatory Actuator(MM-LOA) using spring damper based on the design procedure and the characteristic analysis. MM-LOA is applied to variable load such as vaccum pump and compressor, The structure of piston type is selected to reduce a noise. MM-LOA has over-displacement in starting state because of the low inertia of mover To improve the starting characteristic, spring damper is used. The optimum spring constant of spring damper is detected and in consideration of spring damper, MM-LOA redesigned. The parameter is calculated by Finite Element Method(FEM). For the dynamic characteristic analysis, time differential method composed of voltage and kinetic equation is used. The propriety of the improved model is verified through the experimental results.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.184-186
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• 2002

$ITO_{(n)}/Si_{(p)}$ solar cell was fabricated by vaccum deposition method under the resistance heating with substrate temperature kept about 200[$^{\circ}C$] and than their properties are investigated. The cell charateristics can be improved by annealing but are deteriorated at temperature above 650[$^{\circ}C$] for longer than 15[min].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.97-100
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• 2001

This paper presents the characteristics of Ta-N thin-film strain gauges as high-temperature strain gauges, which were deposited on Si substrate by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(4∼16 %)N$_2$). These films were annealed for 1 hour in 2x10$\^$-6/ Torr vaccum furnace range 500∼1000$^{\circ}C$. The optimized conditions of Ta-N thin-film strain gauges were annealing condition(900$^{\circ}C$, 1 hr.) in 8% N$_2$ gas flow ratio deposition atmosphere. Under optimum conditions, the Ta-N thin-films for strain gauges is obtained a high resistivity, $\rho$=768.93 ${\mu}$Ω cm, a low temperature coefficient of resistance, TCR=-84 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=4.12.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.381-385
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• 2003

In this paper, a co-axial type ozonizer varied with discharge gap was designed and manufactured for investigating $\circled1$ discharge characteristics with variation of output voltage power supply, flow rate and gap $\circled2$ ozone generation characteristics with variation of flow rate, gap and discharge power. pure oxygen was used as process gas of the co-axial type ozonizer. In this paper, a double cylindrical type superposed silent discharge type ozonizer which internal electrode can be produced a vacuum has been designed and manufactured. Discharge and ozone generation characteristics have been investigated in accordance with output voltage of power supply, flow-rate, discharge power and vacuum of internal electrode.