• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.269-273
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• 2003

In this paper the HTS current lead for superconducting device is studied numerical method. The current lead is cooled by surrounded He gas by natural convection. To find wall heat flux, the linearization method is adopted Numerical results using natural convection cooling are compared with conventional cooling methods such as conduction cooling and vapor cooling. The results shows that the minimum heat dissipation is much smaller than conduction cooling. Also, the minimum heat dissipation is obtained for the non-zero gradient of temperature at warm end. HTS current lead operating current sharing mode is reduce heat flow to superconducting system.

• 설비공학논문집
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• 제12권12호
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• pp.1066-1072
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• 2000

This study is to investigate the pressure wave characteristics and the absorption of maximum and minimum pressure generated by instantaneous valve closure at the end of the straightening copper piping system with and without a water hammer arrester. Experiments were conducted under the following conditions : initial pressure 1~5 bar, flow velocity 0.6~3.0 m/s, water temperature $20^{\circ}C$ and air volume of water hammer arrester $80~180^cm^3$. Experimental results show that the optimum air volume of water hammer arrester is 110㎤.

• Journal of Ginseng Research
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• 제8권2호
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• pp.135-152
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• 1984

Solubility and degree of swelling of the starch were about 15% and 30%, respectively when the starch in agueous solution was heated at 90$^{\circ}C$ for 30minutes. The starch showed no singnificant differences in the degree of swelling and soblubility with a growing period of ginseng. The starch was begun gelatinize at 50-55$^{\circ}C$ and completed at 65-70$^{\circ}C$ by the amy tical methods of X-ray diffraction, disappearance of crystalinity. Brabender angly lographic analysis and amylase digestion test. The maximum and minimum peak viscosities of 10% starch solution were 5.500 B.U and 1960 B.U, respectively. The starch showed no significant differences in pasting temperature, maximum and minimum viscosities on amylogram with a growing period of ginseng. The intrinsic viscosities of the starch and amylose were 0.54 and 1.5-1.9, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.172-174
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• 2003

Using MODIS data and several different compositing algorithms utilizing the average cloud free days in a compositing period, maximum ndvi, or dual maximum NDVI/minimum blue, multi resolution composites (250m, 500m, 1km) have been produced for Southeast Asia, with spectral bands ranging from the visible to short-wave infrared with a single band in the thermal (for land and sea surface temperature). A total of nine composites have been produced for the months of May and August in 2003, including blue, green, red, NIR, three in the SWIR, and several to specifically monitor vegetation health.

• 대한설비공학회지:설비저널
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• 제16권3호
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• pp.305-314
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• 1987

Thermodynamic analysis of a mixed refrigerant refrigeration cycle has been performed by computing thermodynamic properties of various refrigerants. The analyses are carried cut to identify the sources and distribution of the energy degradation by irreversible processes. Heat exchange process with the surroundings produces the entropy and the irreversible loss can be reduced by the mixed refrigerant whose phase change temperature varies during the phase change processes in the evaporator and the condenser. The concept has been applied to find the minimum compression work and thus the minimum energy loss in the overall system, specifically in the case of the mixed refrigerant of R12 and R114. Parametric studies have been added to recognize the various factors affecting the system performance.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.231-236
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• 1997

To improve electrical properties and uniformity of high-low doped n-type GaAs, new ohmic contacts with a low-resistance and the superior uniformity was developed using a concept of hybrid ohmic contact. The hybrid ohmic contact displayed good surface and interface morphology and had minimum contact resistivity of 3${\times}$10-6 $\Omega$$\textrm{cm}^2$ in a wide annealing temperature ranged from 340$^{\circ}C$ to 420$^{\circ}C$, which was much wider than that of conventional ohmic contacts. The microstructural analysis showed that the Pd/Ge ohmic contact at low annealing temperature (∼300$^{\circ}C$) and also annealing temperature (∼400$^{\circ}C$), resulting ij hybrid ohmic contacts.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.95-96
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• 2002

The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

• ALGAE
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• 제19권3호
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• pp.247-255
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• 2004

This study was to clarify the variations in a marine ecosystem through examining the species composition of phytoplankton in the coastal water of Baegyado Island during winter. Water temperature, salinity, SS, NH$_4$-N, NO$_2$-N, NO$_3$-N and SiO$_2$-Si were significantly different and in inverse proportion to the chlorophyll a and species number according to stations and water depth. The total number of species was 88, composed of 94% Bacillariophyceae, 3.4% Chrysophyceae, 2.2% Dinophyceae and 1.1% Euglenophyceae. The dominant species were Rhizosolenia setigera, Skeletonema costatum and Stephanopyxis palmeriana. The maximum of standing crops was $5,450cells{\cdot}ml^(-1)$, while the minimum was $1,700cells{\cdot}ml^(-1)$. The coastal water was influenced with two water bodies which had characteristics of low water temperature - low salinity and high water temperature - high salinity.

• 한국해양공학회지
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• 제15권3호
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• pp.58-62
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• 2001

The objective of research is to clarify the interaction between dislocations and precipitates during high temperature creep deformation behaviors of high n austenitic steels. After measuring the internal stress in minimum creep rate state under applied stress of 236MPa at 873K, a transmission electron microscope (TEM) observation was performed to investigate the interaction between dislocations and precipitates during high temperature creep deformation. The band widths and values of internal stress increased when the nitride precipitates distribute more densely. Fine nitrides disturbed the dislocation movement with pinning the dislocations and perfect dislocations were separated into Shockley partial dislocations by fine nitrides. Coarse nitrides disturbed the dislocation movement with climb mechanism.

• 한국세라믹학회지
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• 제25권4호
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• pp.341-348
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• 1988

Thin films of tin-oxide were prepared by chemical vapor deposition technique using the direct of SnCl4. Resistivity and carrier concentration of deposited SnO2 thin film were measured by 4-point probe method and Hall effect measurement. The results showed the remarkable dependence of electrical properties on the deposition temperature. As the deposition temperature increased, resistivity of deposited film initially decreased to a minimum value of ~10-3$\Omega$cm at 50$0^{\circ}C$, and then rapidly increased to ~10$\Omega$cm at $700^{\circ}C$. Electrical conductance of these films was measured in exposure to H2 gas. It was found that gas sensitivity was affected combination of film thickness and intrinsic resistivity of deposited film. Gas sensitivity increased with decrease of film thickness. Fairly high sensitivity to H2 gas was obtained for the film deposited at $700^{\circ}C$. Optimum operation temperature of sensing was 30$0^{\circ}C$ for H2 gas.