• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.144-150
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• 1985

For the separation of boron isotopes, aminated polystyrenedivinylbenzene ion-exchange resins were prepared by chloromethylation of styrene-divinylbenzene copolymer (DVB 10%), followed by the reaction of methylamine. During the preparation of styrene-divinylbenzene copolymer, heptane for the porous resin and toluene for the non-porous resin were used as diluent, and the pore volume of the resins was determined by mercury porosimeter. In both water and aqueous alcohol solutions, the distribution coefficient of boric acid was decreased in accordance with increasing the alcohol concentration and the number of carbon atoms in the alcohol molecules. As a result of separatioin of boron isotope with nonporous and porous resin in water solvent, the separation efficiency of porous resin is better than that of the nonporous, and the result in both water and 50% methyl alcohol solvent relevant to nonporous resin indicated that the latter was better than the former.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3465-3474
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• 2014

Porous silica particles are the most prevailing raw material for stationary phases of liquid chromatography. During a long period of time, various methodologies for production of porous silica particles have been proposed, such as crashing and sieving of xerogel, traditional dry or wet process preparation of conventional spherical particles, preparation of hierarchical mesoporous particles by template-mediated pore formation, repeated formation of a thin layer of porous silica upon nonporous silica core (core-shell particles), and formation of specific silica monolith followed by grinding and calcination. Recent developments and applications of useful porous silica particles will be covered in this review. Discussion on sub-$3{\mu}m$ silica particles including nonporous silica particles, carbon or metal oxide clad silica particles, and molecularly imprinted silica particles, will also be included. Next, the individual preparation methods and their feasibilities will be collectively and critically compared and evaluated, being followed by conclusive remarks and future perspectives.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.952-959
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• 2012

The photocatalytic reactor was designed to have improved efficiency by enhancing a light intensity of photocatalytic reactor using a reflector coated on the surface at the outer radius of annular shaped photocatalytic reactor. The improved photocatalytic reactor performed to treat waste air containing malodor and VOC with the enhanced light intensity, of which the effect on their removal efficiency was investigated. The intensities of illumination of the improved photocatalytic reactor filled with porous silica-based media and nonporous glass bead media carrying photocatalyst were observed to increase by 28.5% and 30.1%, respectively, compared to those of photocatalytic reactor without any reflector. Using the improved photocatalytic reactor filled with porous silica-based media and nonporous glass bead media carrying photocatalyst, the removal efficiencies were enhanced by 2~3% and insignificantly, respectively. The removal efficiencies of the optimized photocatalytic reactor with reflectors, filled with porous silica-based media carrying photocatalyst, were observed to increase by 26% and 60%, compared to those of photocatalytic reactor (i.e., 19% and 53%), without any reflector, filled with nonporous glass bead media carrying photocatalyst, for hydrogen sulfide and toluene, respectively. The roughness of used reflector surface was measured to be ca. four times as big as that of a commercial mirror. However, their removal efficiencies are expected to be enhanced by increasing an light intensity resulting from lowering the roughness of used reflector coated on the improved photocatalytic reactor in the future.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.3
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• pp.195-200
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• 1992

This is a case report of correction of traumatic right frontal bone depression. Traditionally, autogenous and homogenous corticocancellous bone have been inlaid or onlaid. This patient who had frontal bone depression of right forehead was operated with an extracranial augmentation procedure using Hydroxyapatite materials. The postoperative course was unremarkble and the patient was satisfied with a good facial contour. Now We will report the results.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.945-951
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• 2012

The effect of photocatalyst-carrying media porosity on the photocatalytic removal efficiency of malodor and VOC of waste air was evaluated when the photocatalytic removal efficiency of porous silica-based media was compared with that of glass bead as control. The amount of photocatalyst coated on the surface of porous silica-based media was observed to be $1,716.3{\mu}g/cm^2$, which was 250% as much as that of nonporous glass bead (control) of $670{\mu}g/cm^2$. The removal efficiencies of hydrogen sulfide and toluene in case of porous silica-based media were observed to be 22% and 82%, respectively, while the removal efficiencies of hydrogen sulfide and toluene in case of nonporous glass bead media were observed to be 19% and 53%, respectively. Therefore, the removal efficiencies of hydrogen sulfide and toluene increased by 16% and 55%, respectively, when the removal efficiencies of porous silica-based media were compared with those of nonporous glass bead media. Thus the increment ratio of the removal efficiency of toluene was observed to be 3.4 times higher than that of hydrogen sulfide.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.06a
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• pp.1-29
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• 1993

막 분리는 막의 물리화학적 특성, 분리대상 물질의 물리화학적 특성, 그리고 물질의 이동현상을 조절하는 압력차, 농도차 및 전위차 등의 추진력, 이 세가지 요소의 조합에 의해 행해진다. 막은 막을 구성하고 있는 물질의 물성, 구조, 막의 응용분야 및 역할 등에 의하여 세공막(Macroporous membranes), 미세공막(Microporous membranes), 비공성막(Nonporous membranes)등으로 분류된다.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.73-80
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• 2000

Aerodynamics in a naturally ventilated multi-span greenhouse with plants was analyzed numerically by the computational fluid dynamics (CFD) simulation. To investigate the potential application of CFD techniques to greenhouse design and analysis, the numerical results of the CFD model were compared with the results of a steady-state mass and energy balance numerical model. Assuming the results of the mass and energy balance model as the standard, reasonably good agreement was obtained between the natural ventilation rates computed by the CFD numerical model and the mass and energy balance model. The steady-state CFD model during a sunny day showed negative errors as high as 15% in the morning and comparable positive errors in the afternoon. Such errors assumed to be due to heat storage in the floor, benches, and greenhouse structure. For a west wind of 2.5 m s$^{-1}$ , the internal nonporous shading screens that opened to the east were predicted to have a 15.6% better air exchange rate than opened to the west. It was generally predicted that the presence of nonporous internal shading screens significantly reduced natural ventilation if the horizontal opening of the screen for each span was smaller that the effective roof vent opening.

• Journal of Powder Materials
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• v.22 no.1
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• pp.15-20
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• 2015

The composite of porous silicon (Si) and amorphous carbon (C) is prepared by pyrolysis of a nano-porous Si + pitch mixture. The nano-porous Si is prepared by mechanical milling of magnesium powder with silicon monoxide (SiO) followed by removal of MgO with hydrochloric acid (etching process). The Brunauer-Emmett-Teller (BET) surface area of porous Si ($64.52m^2g^{-1}$) is much higher than that before etching Si/MgO ($4.28m^2g^{-1}$) which indicates pores are formed in Si after the etching process. Cycling stability is examined for the nano-porous Si + C composite and the result is compared with the composite of nonporous Si + C. The capacity retention of the former composite is 59.6% after 50 charge/discharge cycles while the latter shows only 28.0%. The pores of Si formed after the etching process is believed to accommodate large volumetric change of Si during charging and discharging process.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.171-179
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• 2001

A new passive sampler was developed, improving SPMD (Semipermeable Membrane Devices) that contained triolein in nonporous, low-density polyethylene layflat tubing. Experiments to measure PAHs concentration were carried out at four sites (Dukpo, Sochi, Sohwonggando, Yeonmok) on the southern coast of Korea that were contaminated by oil spills. Passive samplers were deployed at 4 and 8 week intervals at each site. Results showed that bioconcentration levels of PAHs were increased in proportion to exposure duration from all sample sites and accumulation in the passive sampler was much higher than in biota at the Dukpo site. Results of these tests suggest that new passive sampler is a useful tool for measuring bioconcentration organic compounds in aquatic environments.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3274-3280
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• 2011

Monodispersed porous NiO and $Co_3O_4$ microcapsules with a hollow core were synthesized using SBA-16 silica sol and PS as a hard template. The porous hollow microcapsules were characterized by XRD, TEM and $N_2$ adsorption/desorption analysis. After $H_2$ reduction of metal oxide microspheres, they were conducted as an active catalyst in the reduction of chiral butylronitrile and cyanobenzene. The mesoporous metals having a hollow structure showed a higher activity than a nonporous metal powder and an impregnated metal on the carbon support.