• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.166-171
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• 2016

Size reduction is one of the major pre-processing operations in using biomass as a source of energy or raw materials for forest products industry. The grinding characteristics of dried yellow poplar wood chips were investigated using laboratory knife mill with three different screen aperture diameters to provide the basic information for the optimizing of size reduction processes in biomass industry. Average specific energy consumptions were 0.157, 0.137, and 0.093 Wh/g for the screen aperture diameters of 5.0, 7.5, and 9.0 mm, respectively. According to the results of size distribution analysis of ground particles, the sizes of the most of ground particles were much smaller than the aperture diameters of the screens installed on knife mill used in this study.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.184-188
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• 1993

Novel Ustilagomaydis strains, designated as SH1 to 14 containing new types of ds RNA segments, are identified from corn smut in Korea. Among 14 isolates, 7 isolates appear to posses virus particles and the other isolates may contain dsRNA as a plasmid form. The pattern of dsRNA is highly diverse form a typical P-type containing one or more of H, M, and L dsRNAs to the one containing one or move M dsRNAs. It is likely that the strains containing H dsRNA posses virus particles which were confirmed by sucrose density gradient followed with different range of specificity and the activity of the strain (SH14) is stronger than A4 toxin. The sensitivity of 14 isolates is also very diverse and two strains (SH10, SH11) appear tobe universal sensitve strains against 5 tested toxin samples.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.271-272
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• 1996

Assuming that particles can be accelerated to high energies via diffusive shock acceleration process at the accretion shocks formed by the infalling flow toward the clusters of galaxies, we have calculated the expected spectrum of high-energy protons from the cosmological ensemble of the cluster accretion shocks. The model with Jokipii diffusion limit could explain the observed cosmic ray spectrum near $10^{19}eV$ with reasonable parameters and models if about $10^{-4}$ of the infalling kinetic energy can be injected into the intergalactic space as the high energy particles.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.233-234
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• 2003

Fly ash enters axial compressor when a turbomachinery is operated in an adverse environment. We have numerically investigated erosion of the blade and shroud in the turbulent compressor passage flow under the influence of gas-particle two-phase interaction. There have appeared quasi-three dimensional calculations on this subject but not the complete three-dimensional gas-particle interaction as done in the present work. Lagrangian particle tracing technique is used on the base of parallel processing for efficient calculation. Accuracy of the present code is tested using the benchmark lPL nozzle. In the DFVLR compressor blades, we have shown that a large number of particles passing through the tip clearance make impact on the blade tip and on the shroud. Higher degree of erosion is resulted by the heavier particles due to the centrifugal force.

• Nuclear Engineering and Technology
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• v.34 no.5
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• pp.445-454
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• 2002

The sorption of U(Vl) on a domestic granite is studied as a function of experimental conditions such as contact time, solution-solid ratio, ionic strength, and pH using a batch procedure. The distribution coefficients, $K_{d}$＇s, of U(VI) are about 1-100mL/g depending on the experimental conditions. The sorption of U(VI) onto granite particles is greatly dependent upon the contact time, solution-solid ratio, and pH, but very little is dependent on the ionic strength. It is noticed that an U(VI)-carbonate ternary surface complex can be formed in the neutral range of pH. In the alkaline range of pH above 7, U(VI) sorption onto granite particles is greatly decreased due to the formation of anionic U(VI)-carbonate aqueous complexes.s.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.54-55
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• 2016

Recently in the construction industry, industrial by-product admixtures like blast-furnace slag fine particles (BS henceforth) are being used as binding material, reducing the use of cement, and measures to reduce CO₂ emissions are being examined on various levels. However, the BS being used domestically varies depending on the origin of resources, and by circulating BS that is inappropriate to the KS standard, problems are occurring in terms of changes and declines in the quality of concrete which uses it. Therefore in this study the liquid densimeter principle was used to assess various BS fineness qualities; with 100 g/L fixed, a 1,000cc mass cylinder was most appropriate for assessing the quality of cement fineness.

• Journal of the Korean Applied Science and Technology
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• v.25 no.3
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• pp.404-409
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• 2008

The core-shell composite particles of inorganic/organic were polymerized by using styrene(St) as a shell monomer and potassium persulfate (KPS) as an initiator. We studied the effect of core-shell structure of silicone dioxide/styrene in the presence of an anionic surfactant sodium lauryl sulfate (SLS) and polyoxyethylene alky lether sulfate (EU-S133D). We found that when $SiO_2$ core/PSt shell polymerization was prepared on the surface $SiO_2$ particle, to minimize the coagulation during the shell polymerization, the optimum conditions were at concentration of $2.56{\times}10^{-2}mole/L$ SLS. The structure of core-shell polymer was confirmed by measuring the thermal decomposition of polymer composite using thermogravimetric analyzer and morphology of core-shell polymer particles by transmission electron microscope (TEM).

• Fibers and Polymers
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• v.7 no.2
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• pp.139-145
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• 2006

Cotton fabric was treated with montmorillonite (MMT) so as to evaluate its effectiveness on improving its wrinkle resistance. The MMT in emulsion form was applied to cotton fabric by padding and finally the wrinkle resistance of the MMT-treated cotton fabric was improved. Furthermore, instrumental methods were used for studying the presence of MMT particles on the cotton fabric surface. It was noted that nano-scale MMT particles adhered on the fiber surface and the particle size played an important role in influencing the wrinkle resistance of the cotton fabric. The experimental results are discussed thoroughly in this paper.

• The Korean Journal of Community Living Science
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• v.12 no.1
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• pp.23-27
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• 2001

This study is designed to find out the physicochemical quality and the morphological features of Korean wheat flour and imported wheat flour with a view to shed light on their difference. In terms of components, Korean wheat flour and imported wheat flour are similar, but the latter turns out to be better than the former when it comes to crude protein, the ratio of water absorption and the power of maintenance. Yet Korean wheat flour turns out to be better than imported wheat flour. In terms of the chromaticity of wheat flour, the latter turns out to be higher than the former when it comes to L value, while the former turns out to be higher than the latter when it comes to a value and b value. In terms of the morphological features of wheat flour, both are in the shape of an oval with starch particles irregularly attached to gluten. And imported wheat flour is getter than Korean wheat flour in terms of the size of particles.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.491-496
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• 2003

Fe-Ni alloy nanoparticles were prepared by ERC (Evaporation and Rapid Condensation) method, and the crystal structure and the behavior of martensite for the nanosized alloy particles were investigated by X-ray diffraction analysis. The relation between the rate of martensite transformation and the internal strain of austenite was discussed. The lattice spaces of austenite and martensite for the nanoparticles agreed with those of the bulk materials. The rate of martensite transformation from austenite and the internal strain of austenite was reduced with decreasing the average size of Fe-Ni nanoparticles. It was thought that the residual austenite in the Ni content range of 11∼l5at% was caused by the internal strain, and the residual martensite in the Ni content range of 32∼36at% had its origin in the high surface energy of nanoparticles.