• 대한화학회지
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• 제33권6호
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• pp.601-606
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• 1989

Amberite IR 120+양이온 교환수지를 사용하고, 용리액으로 EDTA 용액을 사용하였을 때, 란탄계열원소들($Pr^{3+},\;Nd^{3+},\;Sm^{3+},\;Er^{3+}$)의 분배비와 분리인자에 미치는 온도의 영향과 수지상의 보유이온의 종류에 따르는 영향을 연구하였다. 보유이온들에 있어서는, ${NH_4}^+,\;Na^+,\;K^+,\;Mg^{2+},\;Ca^{2+},\;Zn^{2+}$ 및 $Ce^{3+}$들 중, $Ce^{3+}$이 Nd/Pr의 분리인자를 개선하는데 가장 좋은 효과를 주었으며, $Zn^{2+}$이 Sm/Nd와 Er/Sm이 분리인자를 개선하는데 가장 적당한 보유이온임을 규명하였다. 용리시킬 때 온도의 영향은, 보유이온에 따라 매우 다양하였으며, 온도를 상승시킬 때 분배비는 감소하였다. 그러나 분리인자는 항상 증가하지 않았으며 보유이온이$Ce^{3+}$일 때 온도를 상승시켜 보니, Nd/Pr, Sm/Nd의 분리인자가 증가하였고, 보유이온이 $Zn^{2+}$일 때 온도를 상승시켜 보니 Er/Sm의 분리인자가 증가함을 확인하였다.

• 한국환경과학회지
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• 제20권8호
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• pp.1011-1019
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• 2011

The objective of this research is to evaluate optimal conditions of permeability and selectivity on the polysulfone membrane for efficiency of separation of $CH_4$ by checking four factors which are temperature, pressure, gas compositions and gas flow rates. When higher pressure was applied at the input, lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ were shown. It has the tendency to show lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ at the output as higher temperature at input. The lower flow rates make higher efficiency of recovery of $CH_4$ and lower efficiency of separation of $CH_4$. Finally, over 90% efficiency for $CH_4$ separation and recovery conditions are temperature ($-5^{\circ}C$), pressure (8 bar), gas composition rate (6:4) ($CH_4:CO_2$) and gas flow rate ($5\ell$/min). These conditions make higher separation and recovery efficiency such as 90.1% and 92.1%, respectively.

• 한국재료학회지
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• 제19권2호
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• pp.111-114
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• 2009

For the fabrication of core-shell structure bimetallic lead-free solder balls, both the critical temperature ($T_{cr}$) for the phase separation of two immiscible liquid phases and the temperature coefficient of the interfacial tension between the two separated liquid phases are required. In order to obtain this information, the temperature dependence of the surface tension of 60%Bi-24%Cu-16%Sn(-REM) alloys was measured using the constrained drop method. The slope of the temperature dependence of the surface tension changed clearly at a critical temperature for the separation of two immiscible liquid phases. The critical temperature of the 60%Bi-24%Cu-16%Sn alloy was estimated to be 1097K. An addition of 0.05% Ce decreased the critical temperature to 1085K, whereas that of 0.05% La increased it to 1117K. It was found that the surface tension and its temperature coefficient of the 60%Bi-24%Cu-16%Sn alloy were slightly increased by the addition of 0.05% Ce and 0.05% La. In addition, additions of Ce and La increased the temperature coefficient of the interfacial tension.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.235-241
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• 2002

The process of energy separation in a low pressure vortex tube with air as a working medium is studied In detail. Experimental data of the temperature of the cold and hot air leaving the vortex tube are presented. The variation of the maximum wall temperature along the inner surface of the vortex tube and the temperature distribution in the vortex tube provides useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. In this study Outer tube is used for the application of Diesel engine exhaust. The hot gas flow is fumed 180° and passes the outside of the vortex tube a second time heating it. From this geometric setup of a vortex tube the effects of energy separation and the prediction of the ignition of Diesel Soot is presented by experimental data.

• 설비공학논문집
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• 제11권5호
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• pp.692-699
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• 1999

The vortex tube is a sample device for separating a compressed gaseous fluid stream into two flows of high and low temperature without any chemical reactions. The phenomena of energy separation through the vortex tube were investigated experimentally, to see the effects of the number of nozzle holes on the energy separation. The experiment was carried out with the number of nozzle holes from 1 to 10 by varying inlet pressure and cold mass fraction. The experimental results were indicated that the effective number of nozzle holes for the best cooling performance was found as 4. Also, to find effective use in a given operation conditions, the temperature difference of cold air and the cooling capacity of vortex tube was compared. The result is that cooling capacity was more important than temperature difference of cold air.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.84-93
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• 2001

The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. Average flow rate that flows into a tube is in proportion to square root of inlet pressure. As inlet pressure increases axial and radial temperature distribution in the inner space of vortex-tube increase. As mass flow rate ratio change, separation point moves.

• 대한기계학회논문집B
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• 제38권9호
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• pp.731-737
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• 2014

와류실은 압축된 공기를 이용하여 고온과 저온 가스로 분리할 수 있는 단순한 장치로, 차세대 새로운 열교환기로 각광받고 있으나, 와류실 내부에서 발행하는 물리적 유동특성에 대해 아직까지 많이 알려지지 않았다. 본 연구에서는 온도 분리 현상을 조사하기 위해 실험 및 수치해석을 수행하였다. 공급 압력에 따른 온도 변화를 측정하기 위하여 다수의 압력 및 온도 센서를 사용하였으며, CFD 기법을 적용하여 3차원 비정상 압축성 유동장을 조사하였다. 연구를 통해 온도 분리 현상은 점성일과 밀접한 관계가 있는 공급 압력과 와류실의 직경에 영향을 받았으며, 와류실에서 발생하는 온도분리 현상은 압력구배파의 개념으로 확증할 수 없었다.

• 한국응용과학기술학회지
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• 제28권4호
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• pp.386-392
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• 2011

We are crystallized to the linear low density polyethylene(LLDPE) particles by a thermally induced phase separation(TIPS). TIPS process based on the phase separation mechanism was performed for the LLDPE system which undergoes liquid-solid phase separation. The linear low density polyethylene particle formation occurred by the nucleation and growth mechanism in the metastable region. Although the growth rates depended on the experimental conditions such as the polymer concentration and temperature, the particles were larger when the polymer concentration was higher or temperature was higher. The particles were observed by SEM. The LLDPE particle size distribution became broader when the polymer concentration was higher.

• Nuclear Engineering and Technology
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• 제29권5호
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• pp.361-367
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• 1997

The phase separation in ferrite phase of duplex stainless steel is the primary cause of thermal aging embrittlement of the LWR primary pressure boundary components. In this study the phase separation of simulated duplex stainless steel was detected by Mossbauer spectroscopy and magnetic property analysis by VSM(Vibrating Specimen Magnetometer). The simulated duplex stainless steels, Fe-Cr binary, Fe-Cr-Ni ternary, and Fe-Cr-Ni-Si quarternary allots, were aged at 370 and 40$0^{\circ}C$ up to 5,340 hours. It was observed from Mossbauer spectra analysis that internal magnetic field increases with aging time and from VSM that the specific saturation magnetization and Curie temperature increase with aging time. These result are indicative that phase separation into Fe-rich region and Cr-rich region is caused by thermal aging in the temperature range of 370~40$0^{\circ}C$ In cases of specimens containing Ni, the increase of specific saturation magnetization is much higher. This implies that Ni seems to promote Fe-Cr interdiffusion, which accelerates the phase separation into Fe-rich $\alpha$ phase and Cr-rich $\alpha$' phase.

• 한국세라믹학회지
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• 제34권7호
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• pp.747-757
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• 1997

ZSM-5 zeolite composite membranes have been synthesized from a silica sol solution containing TPABr as an organic template by the dip-coating and the pressurized-coating hydrothermal treatment techniques. The CO2 separation efficiency of synthesized composite membranes was also investigated. The permeation mechanism of CO2 through ZSM-5 membranses was the surface diffusion, and that of N2, O2, and He gases was Knudsen diffusion or activated diffusion depending on the synthetic method of membranes and the measurement temperature. The CO2/N2 separation factor of the membrane prepared by the dip-coating hydrothermal treatment was 2.5 at about 12$0^{\circ}C$, while the ZSM-5 composite membrane synthesized by the pressurized-coating hydrothermal treatment technique showed the CO2/N2 separation factor of 9.0 at room temperature higher than that ever reported in the literature.