• Journal of the Korean Electrochemical Society
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• v.16 no.4
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• pp.204-210
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• 2013

Thin pore-filled cation and anion-exchange membranes (PFCEM and PFAEMs, $t_m=25-30{\mu}m$) were prepared using a porous polymeric substrate for efficient all-vanadium redox flow battery (VRB). The electrochemical and charge-discharge performances of the membranes have been systematically investigated and compared with those of commercially available ion-exchange membranes. The pore-filled membranes were shown to have higher permselectivity as well as lower electrical resistances than those of the commercial membranes. In addition, the VRBs employing the pore-filled membranes exhibited the respectable charge-discharge performances, showing the energy efficiencies (EE) of 82.4% and 84.9% for the PFCEM and PFAEM, respectively (cf. EE = 87.2% for Nafion 1135). The results demonstrated that the pore-filled ion-exchange membranes could be successfully used in VRBs as an efficient separator by replacing expensive Nafion membrane.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.205-210
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• 1983

The determination of charge density and charge distribution in montmorillonite are discussed. The method is based on cation exchange of the inorganic interlayer cations against decylammonium ion and molecular intercalation of n-alcanol. The results obtained from Yougil-bentonite show that charge density of 0.37 per unit formula and cation exchange capacity of 102.5 meq/100g.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.3-12
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• 2010

This study mainly focused on the intergenerational exchange as a plan to revitalize the social participation of the elderly. The purpose of the study is to propose a plan for revitalizing future intergenerational exchange through the present condition analysis in the aspects of activity, space and consciousness for the elderly-centered intergenerational exchange. The study scope is the local welfare level, broad sense of exchange for the aged, children, youths and local residents, and the study objects are the personnel in charge of welfare policy and the staff in charge of operating general social welfare centers and the users of the facilities users. A survey questionnaire type research was sent through post mail to 278 social welfare centers, and 384 government offices within the jurisdictions. Among them, the responses were collected from 22 general social welfare centers and 26 offices within the jurisdictions. A proposal of a plan to revitalize intergenerational exchange that needs to be implemented in future based on the consideration of the present condition and characteristics of the intergenerational exchange of general social welfare center.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.343-350
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• 2004

The charge exchange (or transfer) due to collision with hydrogen has important effects on the physical characteristics of astrophysical plasma. In this paper, collisional ionization equilibrium in the temperature range of ${\sim}1,000--80,000K$ are investigated for C, N, and O ions including the effects of charge exchange. The calculated ionic abundance fractions are compared with those of previous works. The ionic abundance fractions calculated in the paper can be used in understanding the spectroscopic properties of warm interstellar medium. It is also found that the ratio between the degree of ionization of oxygen and that of hydrogen shows big difference with the previously well-known result for the environment where the collisional ionization is not important. This implies that investigations on the collisional ionization in the warm interstellar medium are required.

• Korean Membrane Journal
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• v.7 no.1
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• pp.67-70
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• 2005

It is well known as the role of ion exchange membrane with functional group in membrane matrix. Recently, we were reported that the charged mosaic membrane within parallel array of negative and positive charge groups. In this study we are reported the properties for the various transport coefficients of metal and heavy metal ions across charged mosaic membrane based on non-equilibrium thermodynamics is not based on equilibrium state.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.194-197
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• 2002

Ion exchange is a chemical reaction between the ions in solution phase and ions in solid phase and is widely used in softening, demineralization, removal and collection of specific ions, and ion migration in the ground water. The ion selectivity depends on the charge and the hydrated radius of ion. The objective of this study was to examine the applicability of anion selectivity obtained from the ion exchange equilibrium OH/sup -/ < F/sup -/ < HCO/sup -/ < Cl/sup -/ < Br/sup -/ ≤ NO₃/sup -/ < SO₄/sup 2-/ to the column ion exchange. The column ion exchange was facilitated in the lower charge of counter-ion in the background electrolyte.

• Membrane Journal
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• v.19 no.2
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• pp.129-135
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• 2009

The cation exchange membrane using the block co-polymer of polysulfone and polyphenylenesulfidesulfone was prepared for a separator of all-vanadium redox flow battery. The membrane property of the prepared cation exchange membrane was measured. The thermal stability of the prepared cation exchange analyzed by TG showed a more stable than that of Nafion117. The lowest measured membrane resistance, equilibrated in 1mol/L $H_2SO_4$ aqueous solution, $0.96{\cdot}cm^2$ at 3 cc of CSA (chlorosulfuricacid) which was introduction agent of ion exchange group. Electrochemical property of all-vanadium redox flow battery using the prepared cation exchange membrane was measured. Electromotive force in 100% of state of charge was 1.4 V which was that of all-vanadium redox flow battery, and cell resistance in charge and discharge at each state of charge had a low value compared with that of all-vanadium redox flow battery using Nafion117.

• Nuclear Engineering and Technology
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• v.23 no.4
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• pp.420-425
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• 1991

The Rb charge exchange cell is constructed as the He- ion source of the SNU 1.5- MV Tandem Van do Graaff accelerator. The characteristic experiment is carried out in order to determine the optimum operational conditions of the cell. The $He^{+}$ ion beam with the energy of 1~10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He- ions by the two step charge exchange reaction, i.e., $He^{+}\;+\;Rb\;{\rightarrow}\;He^{\circ\ast}\;+\;Rb^{+}\;and\;He^{\circ\ast}\;+\;Rb\;{\rightarrow}\;He^{-}\;+\;Rb^{+}$. From the experimental results, it is found that the maximum fractional yield of $He^{-}$ ions is produced at He+ ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be $370\;^{\circ}C{\;}and{\;}95^{\circ}C$ respectively. Under the optimum operational condition the maximum fractional yield of $He^{-}$ ions is $2.42\pm0.02%$ This charge exchange cell is proved to be an effective system for the production of He- ions.

• Journal of Photoscience
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• v.6 no.3
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• pp.91-96
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• 1999

Zeolites and microporouos materials continue to attract attention as novel hosts for photochemical reactions. Zeolities are attractive because of their ability to selectivity exchange and incorporate species within the void spaces and interconnecting channels, providing a spatial arrangement of molecules. Our research has primarily focused on intrazeolitic electron transfer from excited Ru(bpy)32+ in supercages of zeolite Y to a series of bipyridinium ions. In the Ru(bpy)32+ viologen-zeolite Y samples, the slowing of the back electron transfer from the bipyridinium radical cation to Ru(bpy)32+ allows for charge propagation via self exchange between diquat molecules. This provides an opportunity for permanent charge separation. When the migrating charge on the diquat radical within the zeolite reaches the surface, it can be transferred to a neutral viologen (PVS) in solution, resulting in permanent charge separation. The advantage of long-lived charge separation can be exploited for useful chemistry if suitable catablysts can be assembled on the zeolities. We have studied Ru(bpy)2 as water oxdiation catalysts. We have demonstrated that synthesis of RuO2 fibers on a zeolite via thermal decomposition of Ru3(CO)12 leads to the most active water decomposition catalyst reported to date. Because of the extensive interest of photochemical water reduction to H2, much is known about catalytic systems usin gone electron catalyst, and even more importantly, that no reaction of viologen occurred with H2 over this catalyst. The present challenge is to incorporate all these elements of the system into an architecture and we are examining zeolite membranes for this purpose.

• Journal of the Korean Ceramic Society
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• v.22 no.6
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• pp.53-57
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• 1985

Korean montmorillonite from Youngil district was characterized by Alkylammonium derivatives. This method was very sensitive to the basal plane spacing d and the charge in the layer charge. The result include the values of average layer charge, charge distribution, equivalent area. interlayer cationic exchange capacity (C, E, C) and total C. E. C.