• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.8-11
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• 1994

Disposal of hazardous ions in the aqueous streams is a significant industrial waste problem.. Waste streams from electronics, electroplating, and photographic industries contain metal ions such as copper, nickel, zinc, chromium(IV), cadmium, aluminum, silver, and gold, amongst others in various aqueous solutions such as sulfates, chlorides, fluorocarbons, and cyanides. Typical plating solutions having similar compositions are listed in Table 1. Spent process streams in catalyst manufacturing facilities also contain precious metals such as Ag, Pt, and Pd. Developing an effective recovery process of these metal ions for reuse is important.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.589-592
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• 2006

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.3-6
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• 2004

Industrial gas separation by membranes began in 1980 with the introduction of hollow-fiber polysulfone membrane systems by Permea, at that time a division of Monsanto. This first application was the recovery of hydrogen from ammonia reactor purge gas and was soon followed by the generation of nitrogen from air. Today, membrane gas separation ranks second behind cryogenic distillation in terms of nitrogen production, and this application has drawn the industrial gas companies into the membrane field.(omitted)

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.42-43
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• 2006

We have prepared random, block and graft copolymers with single or dual sensitivities to various stimuli. We have conjugated these polymers to proteins at random lysine sites or at specific sites designed into the protein by genetic engineering. We are also grafting the smart polymers to the surfaces of nanobeads. We are applying these smart conjugates and smart nanobeads in microfluidic devices for various applications, including diagnostics, affinity separations and enzyme bioprocesses. In this talk I will update our work with these interesting hybrid systems.

• Fire Science and Engineering
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• v.16 no.1
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• pp.45-50
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• 2002

This study set its bases needed for building fire risk analysis by examining general concept and definitions of fire risk analysis, and its access methods. Upon this basis, by using a computer program FREM, we brought the type of hazards out of the fire risk assessment applied to the typical 100 high-rise buildings in and out of this country. In this process, we also sorted out the programs arising from the application of a foreign born tool to domestic conditions. the credibility of fire separations and automatic fire protection system in a building would be the two most important things in an attempt to evaluate fire risk in high-rise buildings. In addition, it is vital for the purpose of securing fire safety in high-rise buildings that the systems should be properly installed and carefully maintained. When we try hard to study the evaluation standards to the above systems and, someday in the future, to employ them in evaluating fire risks in high-rise buildings, we can measure the risks much more precisely with less expenses than that we needed today.

• Journal of The Korean Astronomical Society
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• v.42 no.3
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• pp.39-45
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• 2009

We investigate the degeneracy in the pattern of central microlensing perturbations of a pair of planetary systems where the planets are located from the primary with projected separations in units of the Einstein radius s and $s^{-1}$, respectively. From this, we confirm the fact that although alike, the patterns of central perturbations induced by a close (s < 1) planet and a wide (s > 1) planet are not identical and the degree of difference depends on the planet/primary mass ratio and the planet-primary separation. We find that the difference can be greater than 5% for planetary systems with lensing parameters located in the parameter space of (1/1.8 < |s| < 1.8, q > $5{\times}10^{-3}$), (1/1.3 < |s| < 1.3, q > $1{\times}10^{-3}$), and (1/1.2 < |s| < 1.2, q > $5{\times}10^{-4}$), where q represents the planet/primary mass ratio. Although this range occupies a small fraction of the entire parameter space of planetary systems, we predict that the chance of resolving the close/wide degeneracy would not be meager considering that the planet detection efficiency is higher for planets with resonant separations (s $\sim$ 1) and heavier masses. We also find that the differences between the perturbation patterns are basically caused by the effect of the planetary caustic. This explains the tendency of the perturbation difference where (1) the difference increases as the planet/primary mass ratio increases and the separation approaches the Einstein radius, (2) the region of major difference is confined within the region around the line connecting the central and the planetary caustics, and (3) a wide (close) planetary system has a more extended central perturbation region toward the (opposite) direction of the planet.

• 한국해양학회지
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• v.29 no.4
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• pp.392-401
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• 1994

We examined the temporal characteristics of the oceanic eddy diffusion at 5 coastal regions of Korea by measuring the separation distances of multiple drifters released simultaneously at the same by the GPS and Decca transponder system. The observed variance of separation distance, for the time scales from minutes to hours, is proportional to t/SUP m/ with scaling exponent m between 1.2 and 2.0. The observed Lagrangian trajectories of drifters show fractal characteristics instead of random walk or Brown motion. As an effort toward a development of a realistic model of the oceanic eddy diffusion, we simulated the Lagrangian trajectories of drifters by fractional Brown motion (FBM) model. The observed variances of drifter separations can be generated by the FBM process provided the Hurst exponent is the same as the observed one. We further showed that the observed power law in the variance of drifter separations cannot be simulated with an ordinary Brown motion or random walk process.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.848-852
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• 2005

The two important problems to solve before the industrialization of the iodine-sulfur (IS) process are (i) methods to separate $H_2SO_4$ and HI and (ii) to maintain constant components. However undesired reaction was occurred and $H_2S$ and S were formed during the Bunsen reaction. It is necessary to forbid the undesired reaction between $H_2SO_4$ and HI by separating the two acids into two different layers. The experimental conditions for the present study was chosen in such a way that to achieve the separation between the two acids and minimize the side reaction. $H_2S$ formation was reduced and the separations of the two liquids were occurred at $H_2O$ molar fraction from 0.86 to 0.909. But the separations between the two liquids were not occurred at $H_2O$ molar fraction more than 0.92.

• Membrane Journal
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• v.30 no.6
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• pp.385-394
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• 2020

In the gas separation process, the separation membranes have to not only show high gas transport and selectivity but also exhibit exceptional stability at high temperature and pressure. However, when the polymeric membranes (particularly, glassy polymers) are exposed to the condensable gases (i.e., CO2, H2S, hydrocarbon, etc.), the polymer chains are prone to swell, leading to low stability. As a result, the plasticization behavior reduces the gas selectivity in the separation of mixture gases at high pressures and thus results in limited applications to the separation processes. To address these issues, many strategies have been studied such as thermal treatment, polymer blending, thermally rearrangement, mixed-matrix membranes, cross-linking, etc. In this review, we will understand the plasticization behavior and suggest potential methods based on the previously reported studies.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.64.1-64.1
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• 2015

In the present study, we examine the dependence of solar proton peak flux at SOHO and STEREO on 3-D CME parameters (radial speed, angular width, and longitudinal angular separation between its source region and the magnetic footpoints of spacecraft). For this we consider 38 proton enhancements of 16 SEP events observed by SOHO, STEREO-A, and/or B from 2010 August to 2013 June. As a result, we find that the enhancements are strongly dependent on these three parameters. The correlation coefficient between proton peak flux and CME speed is about 0.42 for the cases the footpoints are located inside the lateral boundaries of angular widths, while there is no correlation for the events outside the boundaries. The correlation coefficient between peak flux and angular separation is -0.51. We find that most of strong proton events occur when their angular separations are closer to zero, supporting that most of the proton fluxes are generated near the CME noses rather than their flanks.