• Journal of Powder Materials
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• v.12 no.3
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• pp.192-200
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• 2005

Ultrafine copper powder was prepared from $CuO-H_2O$ slurry with hydrazine, a reductant, under $70^{\circ}C$. The influence of various reaction parameters such as temperature, reaction time, molar ratio of $N_2H_4$, PvP and NaOH to Cu in aqueous solution had been studied on the morphology and powder phase of Cu powders obtained. The production ratio of Cu from CuO was increased with the ratio of $N_2H_4/Cu$ and the temperature. When the ratio of $N_2H_4/Cu$ was higher than 2.5 and the temperature was higher than $60^{\circ}C$, CuO was completely reduced into Cu within 40 min. The crystalline size of Cu obtained became fine as the temperature increase, whereas the aggregation degree of particles was increased with the reaction time. The morphology of Cu powder depended on that of the precursor of CuO and processing conditions. The average particle size was about $0.5{\mu}m$.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.253-256
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• 2004

Recently, construction works of scale are getting larger with economic growth. Shotcreting is one of major processes in tunnels construction. Accelerator is used in tunnel and underground structures to ensure early strength of shotcrete. Silicate based accelerator and aluminate based accelerator is getting widely in the field. But these accelerators have many problems due to decesase of long-term strength and low quality of the hardened shotcrete. in order to solve these problems, recently developed powder types cement mineral accelerator. In this study, we tested chloride permeability, freezing and thawing and accelerated carbonation of shotcrete. As a result of the test, wet-mixed shotcrete with powder types cement mineral accelerator exhibited durability improvement compared to the conventional shotcrete accelerator.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.13-14
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• 2017

In this paper, research for use possibility as silica source of waste concrete powder discharged from direct and indirect carbonation has progressed. For the research, properties on the extruding panel using waste concrete powder with high silica content is evaluated. As the results, compressive strength of specimen is increased 24% compared to control specimen when waste concrete powder replaced 50%, that is discharged from carbonation process, as silica source.

• Korean Journal of Materials Research
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• v.11 no.9
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• pp.763-768
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• 2001

Molybdenum-based thermal spray powder is widely used for coating the moving parts of the internal combustion engines due to its excellent wear resistance. A composite powder of the $Mo_{40}(Al_{1-x}Si_x)_{60}$ system was synthesized using the SHS method. The synthesized bulk was pulverized and specially treated to produce thermal spray powder. It was found that the synthesis reaction consisted of two-steps: the formation of $Al_8/Mo_3$ and the formation of Mo(Al,Si)$_2$. Both the temperature and the rate of the SHS reaction linearly increased with the increase of the value of x in $Mo_{40}(Al_{1-x}Si_x)_{60}$, The temperature and the rate of the reaction were also affected by the compacting density of the specimens, exhibiting the maximum valves at 62% and 60%, respectively. Since spherical shape is advantageous to the thermal spraying process, shape-control of the powder was attempted with PVA as a binding additive, resulting in the successful production of almost perfectly spherical powder of 80 $\mu\textrm{m}$ Ø$(d_{50})$ mean particle size.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.377-382
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• 2007

Porous mineral coating have been fabricated and applied for basic research on their slow release action to a fertilizer. Feldspar was selected as raw mineral for the coating and two different particle sizes of powder were prepared. Slow-release action was estimated by using a potassium sulfate fertilizer. Spherical pellets were prepared with a pan-type pelletizer and then screened into sizes ranging 1.4 to 2.35mm. While the fertilizer pellets were rotated in the pelletizer again, the feldspar powder and 0.5% polyvinyl alcohol solution were simultaneously sprayed on the pellets. The fertilizer pellets coated with feldspar powder were fabricated. The pellets were heated to increase their strength and screened to sort by coating thickness. Potassium releasing tests were conducted for 40 days and the performance for slow-release action was estimated as functions of the heating temperature, coating thickness and raw mineral powder size. The Burst effect caused high initial releasing rate. Releasing kinetics was proportional to concentration of potassium in pellets. The pellet that was fabricated with $27.4{\mu}m$-sized feldspar and heated at $1050^{\circ}C$ showed a releasing rate of 43% on the 40th day.

• Culinary science and hospitality research
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• v.7 no.1
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• pp.135-145
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• 2001

This study was undertaken to analyze chemical composition, minerals and texture characteristics of Pongnipgangjung in various volumes of adding Pongnip powder. With increasing Pongnip powder level, moisture, total nitrogen, crude protein, crude fat and crude ash contents were significantly increased. Ca, P, K and Mg contents of Pongnip powder 1%, 3%, 4% was higher than Pongnip flour free group. According to rheometer evaluatuion, Pongnipgangjung added Pongnip powder 1% showed higher level of hardness than Pongnip powder 3%, 4% and free group. In sensory evaluation, the results of preference are in the following order Pongnipgangjung added Pongnip powder 1%, 3%, 4% and free group.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.103-111
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• 2011

This study examined rheological properties of blast furnace slag and ash paste that are widely used as cement concrete for mineral admixture in current. In that way rheological properties of the paste of mineral admixture only was examined. The result of this study were as follow: In order to analyze that the rheological properties of the mineral admixture only, fine particles were produced with grinding machine to 3 particle sizes. These powders in general from the result of comparison with and analysis of rheological properties and the coefficient n and De values. The result that ash powder was higher in plastic viscosity and yield stress than Slag powder, and with the same n value, ash powder showed higher plastic viscosity and yield stress than Slag powder. But Slag powder in particle size distribution showed a sensitive tendency on changing in rheological properties.

• Journal of the Korean Society of Food Culture
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• v.31 no.6
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• pp.597-604
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• 2016

This study was performed to investigate the quality characteristics of lotus root tea (LT) prepared with Gardenia jasminoides powder (GLT) and Rubus coreanus Miquel powder (RLT). The proximate compositions, physicochemical properties, mineral contents, and sensory evaluations of samples were measured. GLT sample showed higher contents of crude protein, crude fat, crude ash, and moisture (p<0.001) as well as pH (p<0.001) compared to LT and RLT. In terms of color, lightness (L) and yellowness (b) of GLT were the highest among the samples, whereas redness (a) of GLT was the lowest. The results of mineral analysis showed that the mineral contents of K, Ca, and Fe of LT were the highest, whereas the content of Mg of GLT was the highest. The results of browning color intensity of all samples showed that LT had the lowest. GLT showed higher contents of water soluble solids than LT and RLT. In the sensory evaluation, the scores of color, flavor, aftertaste, feeling of throat, and overall preference of LT and GLT were significantly higher than those of RLT. From the findings, this study suggests that addition of Gardenia jasminoides powder was effective for preparation of lotus root tea in the aspects of consumer acceptability.

• Journal of Oriental Neuropsychiatry
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• v.10 no.1
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• pp.159-177
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• 1999

In the study on the mineral substance used in Dong Eu Bo Gam(range of 'Sin') and the recent prescription of china, the results were as follows. 1. According to Dong Eu Bo Gam, Realgar was used for Sa-Su most often and Gold-leaf, Succinum, especially Cinnabaris were used for amnesia, epilepsy, a general term of manic-depressive psychosis too. The most kinds of mineral substance used for epilepsy. 2. According to recent prescription of china, Fossilia Ossis Mastodi got the most, and Succinum, Cinnabaris, Lapis Chloriti, Haematitum, Magnetitum, Gypsum Fibrosum, Fossilia Dentis Mastodi, iron powder were used frequently. For external application, Sulfur was too. And most kinds of mineral substance were used for epilepsy and schizophrenia. 3. Realgar, Gold-leaf, Succinum, Cinnabaris, Lapis Chloriti, Haematitum, Magnetitum, Gypsum Fibrosum, Fossilia Dentis Mastodi, iron powder have drug effect for mental disease, especially for epilepsy induced by terror. 4. For Application of mineral substance, it should be considered that the chemical elements of mineral substance act on human body. 5. For drug effect, it is important to make clear of original prescription.

• The Korean Journal of Community Living Science
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• v.28 no.2
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• pp.203-215
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• 2017

This study was carried out to compare the major nutrient components and antioxidant activities of Stachys sieboldii Miq leaf and root powders. For proximate compositions, crude protein and crude fat contents of leaf powder were higher than those of root powder, whereas contents of crude ash and carbohydrates were lower in leaf powder. The content of glutamic acid was greater in amino acids of leaf and root powders, and contents of total amino acids and essential amino acids were higher in leaf powder compared with root powder. Root powder contained a higher level of total unsaturated fatty acids than leaf powder. Total contents of organic acids were higher in leaf powder; tartaric acid was the major organic acid in leaf powder, and malic acid was the major organic acid in root powder. The content of vitamin A was higher in leaf powder than in root powder. However, vitamin E content was higher in root powder than in leaf powder. Total mineral contents of leaf powder were higher than those of root powder, and mineral contents of leaf and root powders were in the order of K>Ca>Mg. Extract yields of leaf and root powders were 27.21% and 58.51%, respectively. Total polyphenols and total flavonoids of leaf extract were 236.35 mg/g and 1.90 mg/g, respectively, which were higher than those of root extract. The $IC_{50}$ values of leaf and root ethanol extracts based on DPPH hydroxyl scavenging were 0.69 mg/mL and 5934.31 mg/mL, respectively, and antioxidative activities of ethanol extracts from all Stachys sieboldii Miq parts dose-dependently increased. These results suggest that Stachys sieboldii Miq can be recommended as an edible functional food material.