• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.8
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• pp.703-710
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• 2000

Energy separation characteristic occurring in a counterflow vortex tube was studied experimentally, where air, $C_2$, and R22 were used as working fluids. The experiments were carried out with pressure ratio from 3 to 8 and cold mass fraction(y) from 0.1 to 0.9. As results, Ranque-Hilsch effect showed different results from adiabatic expansion process. Temperature difference in vortex tube outlet was affected by Joule-Thomson effect as well as Ranque-Hilsch effect. The more effective the energy separation was, the more increased the entropy in the cold oulet of vortex tube was.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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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.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.571-576
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• 1996

The 3-stage cascade composed of the multisection-type bithermal $H_2$/$H_2O$-exchange columns was suggested for heavy water separation. In order to study the separation characteristics for the cascade, a matrix equation with 18 simultaneous equations was composed and the concentrations and flow rates were calculated for the all parts of the cascade. Product D-concentration decreases and extraction yield increases with increasing cut in each stage, which is one of the principal parameters of the separation characteristics. The optimization of the 3-stage cascade can be made by case study using the matrix equation.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.1
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• pp.43-50
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• 2016

$^{89}Zr$ with the favorable nuclear decay kinetics and chemical properties is an appealing radiometal for its application in immuno-PET using radiolabeled monoclonal antibodies. Rising demand of ultrahigh purity and high-specific activity $^{89}Zr$ has propelled the radiochemist worldwide to develop an overall efficacious method for its promising separation from the target matrix $^{89}Y$. The requirement of elevated radiochemical purity (${\geq}$ 99.99%) has accelerated the efforts since last two decades to achieve higher decontamination and separation factors of carrier free $^{89}Zr$ over $^{89}Y$ using several suitable separation techniques. However, each of the technique has its own pros and cons which prior to its actual medical application needs to be optimized and thoroughly scrutinized to avoid further complications during radiolabelling of the pharmaceuticals. In this short review article we will specifically consider as well focus on the historical development and the recent advances on the radiochemical separation of $^{89}Zr$ from $^{89}Y$ which will be helpful for the separation scientist involved in this area to understand the existing available means and plan the strategy to investigate and develop the novel techniques to overcome the problems involved in the present methods.

• ETRI Journal
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• v.36 no.1
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• pp.175-178
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• 2014

We introduce the Energy-Based Blind Separating (EBS) algorithm for extremely fast separation of mixed speech signals without loss of quality, which is performed in two stages: iterative-form separation and closed-form separation. This algorithm significantly improves the separation speed simply due to incorporating only some specific frequency bins into computations. Simulation results show that, on average, the proposed algorithm is 43 times faster than the independent component analysis (ICA) for speech signals, while preserving the separation quality. Also, it outperforms the fast independent component analysis (FastICA), the joint approximate diagonalization of eigenmatrices (JADE), and the second-order blind identification (SOBI) algorithm in terms of separation quality.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.121-128
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• 1998

In fields of operating or handling a hydrogen isotope facility, and of the technology for nuclear fusion source management, gas chromatography has been used as one of the practical techniques lot separation and enrichment of hydrogen isotopic gases including tritium. Chromatographic separation experiments of the hydrogen isotope mixture (hydrogen, deuterium and tritium) were carried out by use of a commercially available gas chromatograph. An aliquot of gas sample was injected by a specially designed vacuum sampler into the stream of inert carrier gas which went through the separation column under liquid nitrogen temperature. The complete separation of hydrogen isotopic molecules was observed with an alumina adsorbent partially deactivated by coating with 10% manganese chlorine. In addition, fairly good separation conditions were obtained without any appearance of nuclear spin isomers with shorter retention time, which would be available for the practical applications of the hydrogen isotope separation and enrichment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.55-60
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• 2010

Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold flow. Due to energy separation ability, a vortex tube can substitute for an EGR cooler of the automotive engine. In this study, experimental approach has been performed to analyze the energy separation characteristics of the vortex tube. Energy separation characteristics of the vortex tube has been tested for supply pressure, cold-out pressure, and hot-out pressure. As increasing supply pressure, energy separation effect increased. Maximum temperature exists about 0.85 of the cold-out-flow-ratio, and minimum exists about 0.35. Hot-out temperature of the vortex tube is affected by the hot-out and cold-out pressure. However, for the given conditions, cold-out temperature is independent of exit pressure change. The results from this study can be used for the basic design parameter of the EGR cooler substitute of an automotive engine.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.06a
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• pp.45-58
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• 1994

Over the last 20 years, membrane separation processes, such as reverse osmosis, ultrafiltration and microfiltration, have been widely adopted by different industries. Commercial uses of membrane have displaced conventional separation processes, such as distillation, evaporation, precoat filter and so on. Membrane separation processes are often more capital and energy efficient when compared with conventional separation processes. Membrane devices and systems are almost always compact and modular. These are the well-known advantages of membrane separation processes. The disadvantage of the membrane process is that the process does not have scale merit and thus the membrane process is suitable for the small and middle size applications. Energy saving is, of course, the biggest advantage of the membrane process, and in many industries the membrane processes are employed because of this reason. Membrane process has other big advantage. In many applications membrane processes provide much higher quality of product than conventional processes. The example is ultrapure water production by membrane processes in semiconductor industry. Conventional technologies never offer such good quality of pure water. If you can obtain both energy saving and higher quality of product at the same time by membrane processes, this is the best application of membrane processes. One example is the concentration of orange juice by membrane, which has already been commercialized in Japan. Comparing with the conventional vacuum evaporation process, juice concentrated by the membrane process has much better taste and flavor and the energy consumption in the membrane process is much less than the evaporation process. In this paper, first membrane separation technology will be classified and then Japanese membrane manufacturers and new modules and devices under development in Japan will be introduced. Fourth energy saving in membrane process will be discussed and finally practical applications of membrane processes in Japan will be shown.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.543-549
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• 2023

Thallium-201 (²⁰¹Tl) is a medical radioisotope which emits gamma rays when it decays and used in myocardial perfusion scans in single-photon emission tomography due to its similar properties to potassium. Currently, the Korea Institute of Radiological & Medical Sciences is the only institution producing ²⁰¹Tl in Korea, and optimization of ²⁰¹Tl production research is necessary to meet supply compared to domestic demand. To this end, technical analysis of plating target production and chemical separation methods essential for ²⁰¹Tl production research is conducted. It deals with the process of generating and separating ²⁰¹Tl radioisotope and target production, It can be generated through a nuclear reaction such as ^natHg(p,xn)²⁰¹Tl, ²⁰¹Hg(p,n)²⁰¹Tl, ^natPb(p,xn)²⁰¹Bi → ²⁰¹Pb → ²⁰¹Tl, ²⁰⁵Tl(p,5n)²⁰¹Pb → ²⁰¹Tl, and considering impure nuclide generated simultaneously with the use of proton beam energy of 35 MeV or less, it is intended to be produced using the ²⁰³Tl(p,3n)²⁰¹Pb→²⁰¹Tl nuclear reaction. In particular, the chemical separation of Tl is a very important element, and the chemical separation methods that can separate it is broadly divided into four types, including solid phase extraction, liquid-liquid, electrochemical, and ion exchange membrane separation. Some chemical separations require additional separation steps, such as methods using selective adsorption. Therefore, this technical report describes four chemical separation methods and seeks to separate high-purity ²⁰¹Tl using a method without additional separation steps