• 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.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.42-45
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• 1996

A residue from the newsprint waste was investigated as a filler in adhesive for bonding southern pine plywood. The residue was prepared by drying the wet residue to 8% moisture content and grinding the dry material using a laboratory Wiley mitt with a 75-${\mu}m$(200-mesh) screen. The residue was compared to a commercial filler commonly used in structural plywood adhesives. A total of 48 three-ply panels. 12.7mm nominal thickness and 0.3 by 0.3 m in size, were fabricated at two press times(4 and 5 min) and three assembly times(20, 40 and 60 min). Evaluations of the residue were carried out by performance tension shear tests after two 4-hour boil accelerated aging tests on plywood. The test results included tension shear strength and estimated wood failure values. All plywood made with the residue filler were comparable to the control-bonded plywood. These results indicate that residue from the newsprint waste streams would be suitable as filler for plywood adhesives.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.343-352
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• 2016

Effects of grinding time and chemicals dosage in arsenic removal from contaminated paddy soil in China were investigated using lab scale attrition and froth flotation combining process. Arsenic concentration in the field soil was 76.51 mg/kg, exceeding Korean and Chinese standards, and predominant arsenic compounds fraction in sequential extraction was "residual" (over 80%). After wet sieving, soil with >2 mm and < 0.038 mm showed concentration lower than 'Warning Level' in Korea. Soil with 0.038-0.075 mm, showing the highest concentration, was discarded since it occupied minor weight fraction (10.1%). Thus soil between 0.075 and 2 mm was only used in the combining process. The highest Arsenic concentration in progeny fragments smaller than 0.038 mm reached up to 981.66 mg/kg after 5 min of attrition. Optimal dosage of collector ($C_5H_{11}OCS_2K$) and modifier ($Na_2S$ and $CuSO_4$) in froth flotation process for the selective separation of the chipped progeny particles from the parent fragments were determined both as 200 g/ton. Arsenic removal efficiency in froth flotation process was 38.47% and it was increased to 72.74% in additional flotation process, scavenging. Average arsenic concentration after overall process - wet sieving, attrition and froth flotation - was estimated to 16.45 mg/kg.

• Journal of Powder Materials
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• v.16 no.1
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• pp.43-49
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• 2009

Titanium carbides are widely used for cutting tools and grinding wheels, because of their superior physical properties such as high melting temperature, high hardness, high wear resistance, good thermal conductivity and excellent thermal shock resistance. The common synthesizing method for the titanium carbide powders is carbo-thermal reduction from the mixtures of titanium oxide($TiO_2$) and carbon black. The purpose of the present research is to fabricate nano TiC powders using titanium salt and titanium hydride by the mechanochemical process(MCP). The initial elements used in this experiment are liquid $TiCl_4$(99.9%), $TiH_2$(99.9%) and active carbon(<$32{\mu}m$, 99.9%). Mg powders were added to the $TiCl_4$ solution in order to induce the reaction with Cl-. The weight ratios of the carbon and Mg powders were theoretically calculated. The TiC and $MgCl_2$ powders were milled in the planetary milling jar for 10 hours. The 40 nm TiC powders were fabricated by wet milling for 4 hours from the $TiCl_4$+C+Mg solution, and 300 nm TiC particles were obtained by using titanium hydride.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.238-243
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• 2002

The dielectric properties and synthesis of $LaAIO_3$ ceramics from mixtures of $La_2O_3$ and $AI(OH)_3$ via ground(planetary ball mill) and unground(wet ball mill) were investigated. The single phase $LaAIO_3$ of ground powder was formed at $1000^{\circ}C$, while that of unground powder was formed at $1300^{\circ}C$. Density and grains of ground sample showed 98% of theory density and a uniform size of 0.75\mu\textrm{m}$, respectively, However those of unground sample showed 93% and non-uniform sizes of 4-5 $\mu\textrm{m}$. Dielectric constant and temperature coefficient of capacitance ($\tau$c) of both ground and unground samples were 21~22 and +70~74 ppm$/^{\circ}C$, respectively. Dielectric loss of ground sample(0.0004) was 10 times as low as that of unground sample(0.003) due to a uniform and small gram size.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.120-124
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• 1994

Nine wind vegetables were analyzed for moisture, ash, crude protein, crude lipid and dietary fiber. Wild vegetables contained 33-53% of dietary fiber on a dry weight basis. Dalle (Allium monanthum) contained 49% total dietary fiber and 22% soluble dietary fiber and dodok(Codonopsis lanceolata) contained 55% total dietary fiber and 21% soluble dietary fiber. Wild 8% more dietary fiber than cultivated one. Water holding capacities of wild vegetables were higher than commercial wheat bran and soy fiber, but lower in oil absorption. When wild dodok and dalle were wet milled by blade grinding before sieving the dietary fiber content in dodok was increased from 55 to 83 % with increasing the dietary fiber content in dalle form 49% to 69%.

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.22-31
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• 1992

The Sancheong kaolin was fractionated into 9 size fractions by wet sieving, sedimentation, and centrifugation. The systematic X-ray diffraction combined with electron microscopy shows that the clay mineral composition of each size fraction is related to the original fabric of kaolin. Minerals such as halloysite (10${\AA}$), kaolinite, illite, and goethite which were formed by procipitation from solution are generally concentrated in the finer fractions, whereas verniculite which was formed by pseudomorphic transformation from other primary minerals are concentrated in the coarser factions. Kaolinits of various types which were formed by precipitation or transformation show a wide size range but they are generally concentrated in the coarser fractions. Halloysite or halloysite-kaolinite clusters in coarse fractions are the fragmentation products of the walls of original boxwork clusters in coarse fractions are the fragmentation products of the walls of original boxwork kaolin which escaped the complete dispersion even through the grinding, ultrasonic agitation, and chemical treatment. Separation of fully hydrated halloysite and kaolinite was possible by systematic wet size fractionation. The coarse-grained minerals such as vermiculite and kaolinite are usually removed during the preparation of clay fraction smaller than 2${\mu}m$, whereas the fine-grained minerals such as illite and goethite are overlooked in X-ray diffraction of the bulk samples because of their minor contents. The systematic wet size fractionation is needed for understanding of the exact mineralogy of kaolin of weathering origin.

• Journal of Life Science
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• v.28 no.5
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• pp.605-614
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• 2018

Bee pollen has an outer wall which is resistant to both acidic and basic solutions and even the digestive enzymes in the gastrointestinal tract. Therefore, the oral bioavailability of bee pollen is only 10-15%. A previous study reported on wet-grinding technology which increased the extraction of active ingredients from bee pollen by 11 times. This study was designed to investigate the safety of wet-ground bee pollen. First, a single dose of wet-ground bee pollen was tested in both rats and beagle dogs at dosages of 5, 10, and 20 g/kg and 1.5, 3, and 6 g/kg, respectively. In rats, compound-colored stools were found in those administered 10 g/kg or more of wet-ground bee pollen. In beagle dogs, 6 g/kg of wet-ground bee pollen induced diarrhea in one male for four hours. However, no obvious clinical signs were found through the end of the experiment in rats and beagle dogs. In addition, no histological abnormality was found in all animals. The data indicates that a single dose of up to 20 g/kg of wet-ground bee pollen is safe. Next, the genetic toxicity of nano-sized bee pollen was tested. This study employed a bacterial reverse mutation test, a micronucleus assay, and a chromosomal aberration assay. In the micronucleus assay, there was no genetic toxicity up to the dosage of 2 g/kg. There was also no genetic toxicity in the bacterial reverse mutation test and chromosomal aberration assay. This data provides important information in developing nano-sized bee pollen into more advanced functional foods and herbal medicines.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.397-408
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• 2003

This study was conducted to examine the feeding effects of FFWBG (fermented feedstuff with wet brewer’s grain) and GS(grinding soybean) in Hanwoo steers. For this research, total twenty steers(average body weight : 455.7$\pm$25.9kg) were grouped into control(formula feed), T1(formula feed:FFWBG=60:40), T2(formula feed:GS=80:20), T3(formula feed:FFWBG:GS=50:40:10), and T4(formula feed: FFWBG:GS=40:40:20), each treatment was allocated to four steers. There was a tendency to be increased average daily gain in T1, T2, T3 and T4 compared with the control even though no statistical significance was found. The feed conversion of T1, T2, T3 and T4 were beneficially better than that of control(P<0.05; 8.25, 9.44, 6.69 and 7.71 vs 11.90, respectively). The blood urea nitrogen concentration of T4 was higher than that of control(P<0.05), but the creatinine concentration of T4 was lower than that of control(P<0.05). The glucose concentration of T1, T2, T3 and T4 were higher than that of control(P<0.05; 59.39, 62.44, 62.17 and 54.00 vs 51.00mg/$d\ell$, respectively). The back-fat thickness of T3 was thicker than that of control, T1, T2 and T4. The rib-eye area of T1, T3 and T4 was wider than that of control. Appearances percentage of ‘A’ ranked meat quantity were 66, 33, 75 and 33% in control, T1, T2 and T4, respectively.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.137-147
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• 2017

Sericite is a clay mineral that has a wide applications in the industry, depending on its purity. To maintain sericite's purity as high as possible it is necessary to remove its gangue minerals or control their contents prior to use for high value-added products and applications. In this study, the wet beneficiation of sericite by applying selective grinding and sedimentation techniques, were investigated. The ore mineral was composed mainly of sericite, quartz and calcite. Analysis showed that the content of sericite increased along with the particle size decrease, but the contents of impurity minerals as quartz and calcite were tended to decrease relatively with particle size decrease. The results of liberation tests using an attrition scrubber showed that the increase in residence time and slurry density have increased the generation of fine particles in -325 mesh size range. It was observed, however, that the contents of impurities such as quartz and calcite in such fine particles also increased during prolonged scrubbing. In the dispersed form without breaking, the yield of the recovered concentrate was 15.4 wt% and the $K_2O$ content was 9.84 wt%, after the dispersed slurry was allowed to settle for 20 minutes. On the other hand, the concentrate yield was increased to 23.4 wt% after 10 minute attrition scrubbing and 40 minute sedimentation, while its $K_2O$ content was decreased to 9.71 wt%. Most of final products were observed as platelet-shaped particles containing Si, Al and K which are main component of sericite.