• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.548-552
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• 2010

This study focused on the development of effective adsorbent to remove acetylenes for the purification of isoprene. The adsorbents with various pore sizes from $4{\AA}$ to $5{\AA}$ were prepared to investigate the effect of pore size on selective adsorption of acetylene as an impurity. The pore size of zeolite A was adjusted by ion-exchange between Na and Ca ions. The pore size of adsorbents has affected the removal of acetylenes selectively because of the kinetic diameter of acetylenes, such as 2-methyl-1-butyne-3-yen (IPA) and 2-butyne. In a batch adsorption experiment, 5A zeolite with pore size of $5{\AA}$ showed the highest removal capacity of 2-butyne. However, IPA was hardly removed from isoprene by the A-type zeolites. For the adsorption isotherm, modified Langmuir model was well fitted with 2-butyne adsorption. Moreover, the regeneration of adsorbent was carried out to determine optimum method. The adsorbent heated for 12 h at $300^{\circ}C$ was regenerated significantly.

• Journal of the Korean Ceramic Society
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• v.31 no.9
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• pp.1044-1052
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• 1994

Tape casting technique was successfully applied to produce porous ceramics and multi-layered ceramics containing porous layers, where spherical hollow polymer particles were introduced as pore precursors. In the presence of extreme differences in density and size between Al2O3 and pore precursor particles, hindered settling was effective in preventing segregation of component particles and packing behavior of mixed powders was improved through bimodal packing. There were two transitions in packing behavior of mixed powders. The first transition took place at 40~50 vol% pore precursor addition, where majority of pores changed from close to open pore state. The other transition occured at 60~70 vol% pore precursor addition, where pore precursor particles formed a continuous network structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.90-97
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• 2003

The purpose of this study is to understand the dissipation pattern of excess pore pressure after liquefaction which governs the post-liquefaction behavior of liquefied sand deposits. 1-g shaking table tests were carried out on 5 different kinds of sands, all of which had high liquefaction potentials. During the tests excess pore pressure at various depths, and surface settlements were measured. The measured curve of the excess pore pressure dissipation was simulated using the solidification theory, and from the analysis of the velocity of dissipation, the dissipation pattern of excess pore pressure after liquefaction was examined. The dissipation velocity of excess pore pressure after liquefaction had a linear correlation with the effective grain size ( $D_{10}$) divided by the coefficient of uniformity ( $C_{u}$), and the increase in the initial relative density of the ground played a role in shifting this correlation curve toward an increased dissipation velocity. From the correlation, an approximate method was recommended for prediction of the dissipation curve of excess pore pressure after liquefaction in saturated sand deposits.s.s.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.79-83
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• 2008

We carry out three-dimensional simulation of pore closing processes during upsetting in open die forging. Several pores on a plane section of a cylindrical material are traced at the same time and the results of hydrostatic pressure and effective strain are discussed to reveal the parameters affecting pore closing phenomena. Five different sizes of pores are also investigated by simulation to reveal the pore size effect in pore closing during upsetting. AFDEX 3D is employed for this study.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.67-73
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• 2010

Pine (Pinus densiflora) and aspen (Populus euramericana) wood meals were treated with ozone at various time schedule in acidic condition. The lignin contents and surface area of the ozone treated wood meals were determined and the enzymatic hydrolysis rate of ozonated wood meals was evaluated. The feasibility of enzymatic hydrolysis of the ozone treated wood meal was obviously influenced with the degree of delignification. After ozone treatment of wood meal for 10min, total pore volume were slightly increased in the surface of wood meal. When wood meals were treated with ozone longer than 10min, few change in the pore volume was observed. However, the area of over $50{\AA}$ of pore size is increased with ozonation time. As a conclusion, the rate of enzymatic hydrolysis of wood is more effective with the pore size distribution than the total pore volume.

• Environmental Engineering Research
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• v.22 no.4
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• pp.401-406
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• 2017

Ammonia, $NH_3$, is a key chemical widely used in chemical industries and a toxic pollutant that impacts human health. Thus, there is a need for the development of effective adsorbents with high uptake capacities to adsorb $NH_3$. An adsorbent with a high surface area and a small pore size is generally preferred in order to have a high capacity for the removal of $NH_3$. The use inorganic nanoporous materials as gas adsorbents has increased substantially and emerged as an alternative to zeolite and activated carbon. Herein, mesoporous alumina (MA) was prepared and used as an $NH_3$ adsorbent. MA showed good pore properties such as a uniform pore size and interlinked pore system, when compared to commercial adsorbents (activated carbon, zeolite, and silica powder). MA has free hydroxyl groups, serving as useful adsorption sites for $NH_3$. In an adsorption isotherm test, MA exhibited 4.7-6.5 times higher uptake capacities for $NH_3$ than commercial adsorbents. Although the larger surface areas of adsorbents are important features of ideal adsorbents, a regular and interlinked adsorbent pore system was found to be a more crucial factor to adsorb $NH_3$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.509-514
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• 2003

We performed the experiment to determine the effective factors, such as the initial concentration of protein, pore size of air distributor, SAV (superficial air velocity), pH, salts and temperature related to foaming characteristics. The foam height in a foam generator was increased with the increase of the initial protein concentration and the decrease of pore size. As SAV was increased, the foam height was increased, and the optimum SAV was 0.84 cm/sec. The foam height was highest in the acid region and it was increased with the increase of salt concentration of NaCl and $NaHCO_3.$ The removal efficiencies of TSS (total suspended solid) and turbidity decreased with the increase of the initial protein concentration in the batch foam separator.

• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.1
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• pp.141-155
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• 2000

To examine how the difference of molecular weight distribution of cellulase influenced the beating process according to surface pore size of the fiber, high molecular weight enzyme and low one were applied to soft wood pulp, hard wood pulp, cotton linter pulp. Some enzymes with the distribution of low molecular weight penetrated into cellulose in the proportion of surface pore size and the results were negative as like : the low viscosity, decrease of refining Yield, decrease of fine fibers content and so on. But in cotton linter pulp in the small surface area, the fiber softness was increased and it had a positive result that the paper intensity was high. Other enzymes with the distribution of high molecular weight had an enzyme reaction on the most surfaces of cellulose. They were effective in eliminating the fuzz of hydrophile fine fibers and the freeness was increased.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.129-132
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• 2005

This study analyzes the behavior of adhesion and friction according to the pore size of nanohoneycomb structures in atomic force microscope (AFM). Anodic aluminum oxide (AAO) films are fabricated as nanohoneycomb structures. According to the pore diameters of the nanohoneycomb structures, the adhesive forces and the frictional coefficients arc obtained in AFM, and the behaviors are analyzed in the view of the contact area between the sphere particle and nanohoneycomb substrate. The effective Young's moduli of the nanohoneycomb structures are measured from the nanoindentation tests, and the contact areas at zero applied load are calculated by combining the porosity of the nanohoneycomb structures and the contact radius determined from JKR and DMT theory.

• Journal of the Korean Ceramic Society
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• v.23 no.5
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• pp.93-101
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• 1986

Microporous glasses were prepared from the 50 $SiO_2-44$ $B_2O_3-6$ $Na_2O$(wt%) parent glass by the phase eparation technique and were characterized by SEM, BET, and Gas Adsorption methods to investigate the possiblity of their use as salt-rejection membranes for reverse osmosis. The conditions of the phase separation for the possible glass membranes were optimized for the given parent glass. The temperature and duration of heat-treatment were desired to be lower(853K) and shorter (1/2~1 hr) respectively. The specific surface areas of porous glasses prepared in this study were about 80~120$m^2$/g and their pore size distribution had a unimodal shape(peak pore radius less than 15$\AA$) It was suggested that the porous glass obtained in this work could be effective for salt-rejection in point of pore size distributions but the way to increase its surface area for the high flux must be studied.