• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.865-868
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• 2004

열 진공 증착법(thermal vacuum evaporation)에 의해 p-형 열전박막을 $3{\times}10^{-4}{\sim}3{\times}10^{-6}$ Torr의 범위에서 유리 기판 위에 제조하였다. 제조된 박막의 전기저항은 고진공일수록 저항이 증가하였으며, $Bi_2Te_3$와 $Sb_2Te_3$상을 가지고 있었다. 박막의 조성은 기판의 위치에 따라 변화하였고, 원자 번호가 작을수록 위치의 영향이 크고, 반대로 원자번호가 큰 원소는 그 영향이 작았다. 또한 고진공에서 제조된 박막일수록 상대적으로 저진공에 비해 조성의 변화가 적게 나타났다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.8
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• pp.621-628
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• 2008

A numerical study for the flow, heat and mass transfer characteristics of the evaporating tube with the films flowing down on both the inside and outside tube walls has been carried out. The condensation occurs along the outside wall while the evaporation occurs at the free surface of the inside film. The transport equations for momentum and energy are parabolized by the boundary-layer approximation and solved by using the marching technique. The calculation domain of 2 film flow regions (evaporating and condensation films at the inside and outside tube wall respectively) and tube wall is solved simultaneously. The coupling technique for the problem with the 3 different regions and the 2 interfaces of them has been developed to calculate the temperature field. The velocity and temperature fields and the amount of the condensed and evaporated mass as well as the position where the evaporating film is completely dried out are successfully predicted for various inside pressures and inside film inlet flow rates.

• Journal of Powder Materials
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• v.10 no.4
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• pp.275-280
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• 2003

Synthesis and characteristics of Cu nanopowder were considered by in-situ characterization method using SMPS in pulsed wire evaporation process. With increasing pressure in chamber, particle size and degree of agglomeration increased by increase of collision frequency. Also, it was found from the XRD analyses and BET measurements that crystallite size and particle size decreased with elevating applied voltage. However, SMPS measurements and TEM observation revealed the increase of particle size and degree of agglomeration with increase of applied voltage. These results suggested that particle growth and agglomeration depend on overheating factor in chamber at the early stage and thermal coagulation in filtering system during powder formation until collection.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1102-1105
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• 2008

In this paper, the prediction method of internal temperature for high strength concrete members at high temperature is presented. Finite element method is employed to facilitate thermal analysis for any position of member. In case of water evaporates inside the concrete member by high temperature, the evaporation heat that absorb surrounding temperature is occurred. This effect of the evaporation heat is applied. And the model equations of the material characteristics of high strength concrete by high temperature are proposed. To demonstrate the validity of this numerical procedure, the prediction by the proposed algorithm is compared with the test results of other researchers. The proposed algorithm is good agreement with experimental results including the phenomenon that temperature by the evaporation heat is lost.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.44-49
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• 2013

The refrigerating system are high efficiency and comfortable due to the automation of the system as well as enhance energy saving are contributing to driving system. Previous study the rotational frequency of the compressor was confined to the fixed condition have changed load of evaporator and condenser related about the refrigerator performance characteristic according to the evaporation load and condensation load change tries to be analyze through the experiment. The useful data for the economic driving of the freezing apparatus tries to be drawn. Consequently, it confirmed that refrigerant in the compressor overheated and as the evaporation load increased the specific volume was increased and the coolant circulation rate decreased. In confirmed that condensation load increased the compression ratio and discharge gas temperature increased. It reduced the low-temperature efficiency and condensation calorie and the quality factor was decreased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.186-192
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• 2006

We applied a new charging system using the condensation and evaporation method to charge the submicron particles with a uniform charging performance. The monodispersed NaCl submicron particles were condensed by n-butanol vapor and grew up to micron droplets with a same size, regardless of their initial size. Those condensed droplets were charged in an indirect corona charger. The indirect corona charger consisted of the ion generation zone and the particle charging zone. In the ion generation zone, Ions were generated by corona discharge and some of them moved into the particle charging zone by a carrier gas and mixed with the condensed droplet. And finally, the charged and condensed droplets dried through an evaporator to shrink to their original size. The average charge and penetration rate of the particles before and after evaporation were measured by CPC and aerosol electrometer and compared with those of a conventional corona charger. The results showed that the average charge was $5\~7$ charges and the penetration rate was over $90\%$, regardless of the initial particle size.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.647-653
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• 2013

The evaporation characteristics of nanofluid droplets on a heated solid surface were experimentally investigated. The experiments were conducted using pure water and a nanofluid of water mixed with CuO nanoparticles, and the solid surface was made of a copper block heated by a nine cartridge heater. The experimental results showed that the evaporation rate of the nanofluid droplet was higher than that of the pure water droplet on the heated solid surface because nanoparticles increased the thermal conductivity of the nanofluid. Furthermore, it was found that the evaporation rate of the nanofluid droplet increased with the solid surface roughness. This may be because the actual area of the liquid-solid interface increased with the solid surface roughness.

• Journal of the Korean Society of Combustion
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• v.21 no.3
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• pp.7-15
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• 2016

The fuel in conventional liquid fuel combustor is atomized by spray method for high efficiency and low emissions. To improve the overall fuel efficiency and lower pollutant emissions in liquid fuel combustion systems, the effective spatial and temporal separation of droplet evaporation from normal spray process is needed. In this paper, the recuperation of high temperature burnt gas for fuel evaporation was proposed to develop a cylindrical premixed combustor. The recuperation process using U shaped tube is effective to evaporate the liquid fuel. The results show that the flame mode is changed into red radiation flame, blue flame and lift off flame with decreasing equivalence ratio as gas fuel combustion mode. In particular, the blue flame is found to be very stable at heating load 9.2 kW and equivalence ratio 0.731. NOx was measured blow 105 ppm ($O_2$ zero base) from equivalence ratio 0.705 to 0.835. CO which is a very important emission index in liquid fuel combustor was observed below 5 ppm ($O_2$ zero base) under the same equivalence region.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.8-22
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• 1995

Three dimensional numerical study of non-evaporating and evaporating spray characteristics was performed in a quiescent and motoring condition of direct injection diesel engine. The calculation parameter was breakup model. The breakup models used were Reitz & Diwakar model and TAB model. The modified k-${\varepsilon}$ turbulence model considering the compressibility effect due to the compression and expansion of piston was used. The calculation results of the spray tip penetration and tip velocity using the TAB model showed similar trends comparing with the experimental data. Although the evaporation rate was not nearly affected with the breakup model at the higher injection pressure, in the low injection case, the evaporation rate result using the TAB model became higher than that of R&D model. The evaporation rate was increased with the injection pressure due to the vigorous interaction with the gas field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.4
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• pp.4226-4231
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• 1976

The objective of this study is to investigate the characteristics of the concrete mixture and the plastic shrinkage of concrete exposed to a rapid evaporation immediately after placement, and to measure the shringkage rate according to the cement-mixture. Drying of concrete was conducted under a controlled chamber in which the temperature was 36${\pm}$2$^{\circ}C$, the relative humidity 45${\pm}$2%, and the wind velocity 4${\pm}$1m/sec. All of the concrete mo1ds were made to have good workability as 6${\pm}$0.5cm in slump. The results obtained are as follows; 1) The evaporation rate was 3.36kg/$\textrm{km}^2$, 2.98kg/$\textrm{km}^2$ and 2.91kg/$\textrm{km}^2$ respectively for each concretemixtures 365kg, 335kg and 317kg after 5 hour exposure, and the evaporation was measured at all 55∼57% after 2 hours and additional in 10% on after 5 hours exposure. 2) The weight of the concrete were was reduced to 3.0%, 2.6% and 2.4% respectively for each of them. 3) The shrinkage of concrete was 0.87 mm/m, 0.56mm/m and 0.31 mm/m after 5 hour exposure, and the shringkage of concrete was measured at 84%, 59% and 45% after 2 hours and it in 1∼5% after 5 hour exposure and then stopped. 4) A recommendation for good concrete is that the evaporation should be minimized during 2 hours after placement of concrete, if possible.