• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.31-36
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• 2008

This study was carried out to clarify the effect of silicate application on rice grain quality and storage characteristics in Ilpumbyeo cultivar. In yield and yield components, panicles and spikelet numbers were increased and ripened grain rate was also increased by 2%. Head rice yield was increased by $7.7{\sim}9.5%$ in silicate application. Protein content of milled rice was reduced by $0.2{\sim}0.3%$ and head rice rate was increased by $2.9{\sim}6.7%$ in silicate application due to decrease of chalky and damaged rice rate. In milling characteristics, color separation rate was improved by $4.2{\sim}7.2%$ and colored rice rate was decreased by $5.5{\sim}16.6%$ in silicate application. Acid value of stored brown rice were increased slowly in low temperature and silicate application, but that in room temperature and no silicate application was increased remarkably. The best degree rate of stored brown rice (over than 7.5 of pH) measured by the pH of grain was increased by the silicate application in both low and room temperature. Therefore, it was suggested that the storage characteristics of rice grain was improved by the silicate application.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.22-28
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• 2011

Purpose: This article attempted to examine how teeth for restoration is made in a clinical practice and utilize it as future educational material of teeth formation and basic data for additional research. Materials and methods: This experiment investigated the models sent to milling center for production of zirconia crowns. After scanned with Lava CAD/CAM System (3M ESPE, Seefeld, Germany), they are measured on 'ImageJ (version 1.32j, National Institutes of Health, USA)' program and compared and analyzed. Convergence angle from mesio-distal surfaces and bucco-lingual surfaces of each teeth are measured. Also, bucco-lingual diameter of the region lowered as much as 0.4 mm from incisal edge in anterior teeth except canines.(This measure is defined as the Peak 0.4) The analysis of data between each group was conducted by Windows SPSS statistic program, and was proved significant on 95% confidence level by independent t-test, one-way ANOVA and multiple analysis (Sheff${\'{e}}$ test). Results: The mean value of convergence angle was $18.67^{\circ}$ It is ranked as molar ($26.70^{\circ}$) > premolar ($16.87^{\circ}$) > anterior teeth ($14.81^{\circ}$) in the order of mesio-distal convergence angle; anterior teeth ($22.32^{\circ}$) > molar ($20.93^{\circ}$) > premolar ($15.41^{\circ}$) in the order of bucco-lingual convergence angle. The mean value of Peak 0.4 was 1.18 mm. Conclusion: Convergence angle of abutment of zirconia all ceramic crown has difference depending on the location in the arch. Due to the nature of production of zirconia all ceramic crown, convergence angle of abutment and line angle finishing degree can have an effect on internal suitability of restoration.

• Food Science and Preservation
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• v.22 no.2
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• pp.174-181
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• 2015

This study investigated the physicochemical properties of three different types of rice flour prepared via dry and wet milling. The powder, soft, and hard-types of rice flour were Suwon No. 542, Suwon No. 541, and Unbong No. 30, respectively. The analysis of the proximate compositions of the different types of rice flour showed that their moisture content was 7.03~7.99%, their crude protein was 7.94~8.35%, their crude lipid was 0.71~1.49% and their crude ash was 0.25~0.82%. For the Hunter's color values, the L value was highest in the wet-milled rice flour, the a value was highest in the dry-milled rice flour, and the b value was highest in the dry-milled rice flour. All the samples showed distinctive rice starch particles in the particle analysis using scanning electron microscope. The dry-milled rice flour showed the greatest amount of irregular particles and the coarsest texture. The water absorption and water solubility indices were higher in the wet-milled soft- and hard-type rice flour. The crystallinities of the samples by X-ray diffractography were all A-type, but the crystallinity of the dry-milled hard-type rice flour was higher in diffraction degree. For the amylogram properties, the wet-milled soft-type rice flour showed the highest maximum viscosity, breakdown and setback. In the meanwhile, the dry-milled soft-type rice flour showed the highest initial pasting temperature, onset, peak, and end temperatures despite of the reverse enthalpy.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.120-132
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• 1998

This stusy was to investigate the marginal fitness of porcelain-fused-to- metal crown after succesive firing cycle. Main variables were the degree of marginal curvature of labiocervical margin and the type of alloy. The exaggerated marginal curvature(EMC) was created by additional reduction at the faciocervical wall of the normallized marginal curvature (NMC)-typed ivorine tooth by using milling machine. The difference in the shape was the mid facial margin was placed 2mm apical to cemento- enamel junction in labial surface. Three types of alloy were high noble, noble, and base metal alloy. Test specimens were divided into 8 groups and each group had 8 specimens. Sixty four ceramometal crowns were made totally. Measurement stages were following degassing, opaquing. body porcelain firing, and glazing, and measuring sites were 4. (midmesial, midfacial, middistal, and midlingual). Digital, travelling measuring microscope (0.5 um precision, Olympus. Japan) was used under ${\times}250$ magnification. Within the limitation of this investigation, it was concluded as belows: 1. The pattern of marginal distortion was varied. Degassing stage was not a specific, causative stage that induce most of total marginal distortion during whole procedure fabricating a ceramometal crown. Body firing stage induced discrepancy relatively more than other firing stages. 2. The specimens that were Ni-based alloy and had EMC were distorted persistently following successive fabricating procedures. But marginal openings were decreased after glazing. 3. The release of metal grinding-induced stress was presumed as a cause that induce marginal distortion. 4. The amount of discrepancies of the labial and lingual margins were greater than that of the mesial and distal margin in the specimen that had EMC. 5. Silver-plated die was not enough to resist abrasion during repeated seating of metal copings on the die-holding device.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.32-37
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• 2003

The trend of miniaturization has been applied to the research on micro rockets resulting in prototype rockets fabricated by MEMS processes. In this paper, the development of three-dimensional micro rockets using micro milling as well as the results of combustion and flight tests are discussed. The body of rocket was made of 6061 aluminum cylinder. The three-dimensional micro nozzles were fabricated on brass by micro endmill with 127${\mu}m$ diameter. Two different micro nozzles were fabricated, one with 1.0mm of throat diameter and the other with 0.5mm. The total mass of rocket was 7.32g and that of propellant was 0.65g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle form the ground resulted in 46m-53m of horizontal flight distance

• Food Science and Preservation
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• v.10 no.1
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• pp.70-74
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• 2003

The distribution of mesophilic and thermophilic bacteria in milled rice was not different according to growing land and variety of rice. However, The number of these bacteria were abundant in milled rice of lower milling degree or longer storage period. The growth of thermophilic bacteria in cooked rice of electric rice cooker was rapidly increased during storage of lower temperature below 75 $^{\circ}C$. Thermophilic bacteria were not appeared just after cooking. After cooked rice was stored far 18∼24 hon thermophilic bacterial growth was rapidly increased by changing spore to vegetative cell. The positive relation between cell number of thermophilic bacteria and occurrence of off-odor was slightly observed. The number of thermophilic bacteria in upper cooked rice of oven and was higher than those in inner and lower cooked rice. Major volatile compound of milled rice cooked and stored in electric rice cooker was hexanal oriented from rice. After long storage, it was confirmed that furan was major volatile compound as off-odor.

• Food Science and Preservation
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• v.14 no.1
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• pp.18-23
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• 2007

This study investigated the effectsof whiteness and packing conditions on the quality characteristics of milled rice during storage at $25^{\circ}C$. Three kinds of packing materials (kraft paper sealed polyethylene and perforated polyethylene) were used to pack milled rice of different whiteness grades (36, 38, 40 and 42). The moisture content and weight of milled rice packed in kraft paper dropped very rapidly compared to values from milled rice packed in polyethylene because of high gas exchange through the paper. On the other hand, the increase in fat acidity of milled rice packed in kraft paper was less than that of milled rice packed in polyethylene because the moisture content of paper-packed rice fell rapidly. The overall quality of cooked rice rose with whiteness, and dropped with extended storage. The overall eating quality of milled rice paced in perforated polyethylene was bestwhen rice was prepared for the table after 8 weeks of storage.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.157-160
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• 2008

A series of $La_2O_3$-added zincborosilicate glasses was fabricated by systematically varying $La_2O_3$ addition up to 15mol% under the constraint of a ZnO:$B_2O_3$ ratio of 1:2. The degree of water leaching after ball milling of the prepared glasses in water medium was relatively quantified by the change in zinc peak intensity in energy dispersive spectroscopy. 8mol% of $La_2O_3$ was the most efficient addition in inhibiting the glass leaching by water. The role of $La_2O_3$ in inhibiting the leaching was explained in terms of change of structural units in the glass network. When the optimum 8mol% $La_2O_3$-added ZnO-$B_2O_3$ glass was used as sintering aid for $Al_2O_3$, the fabricated alumina-glass composite at $875^{\circ}C$ demonstrated dielectric constant of 6.11 and quality factor of 15470 GHz, indicating the potential of leaching-minimized $La_2O_3-ZnO-B_2O_3$ glass for application to low temperature co-firing ceramic technology.

• Korean Journal of Materials Research
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• v.21 no.9
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• pp.520-524
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• 2011

Porous W with controlled pore characteristics was fabricated by a freeze-drying process. $WO_3$ powder and camphene were used as the source materials of W and sublimable vehicles, respectively. Camphene slurries with $WO_3$ contents of 10 and 15 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of a slurry was done in a Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$ while the growth direction of the camphene was unidirectionally controlled. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was hydrogen-reduced at $800^{\circ}C$ for 30 min and sintered in a furnace at $900^{\circ}C$ for 1 h under a hydrogen atmosphere. Microstructural observation revealed that all of the sintered samples were composed of only W phase and showed large pores which were aligned parallel to the camphene growth direction. The porosity and pore size increased with increasing camphene content. The difference in the pore characteristics depending on the slurry concentration may be explained by the degree of powder rearrangement in the slurry. The results strongly suggest that a porous metal with the required pore characteristics can be successfully fabricated by a freeze-drying process using metal oxide powders.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.339-343
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• 2013

Porous Ti-systems with unidirectionally aligned channels were synthesized by freeze-drying and a heat treatment process. $TiH_2$ powder and camphene were used as the source materials of Ti and sublimable vehicles, respectively. Camphene slurries with $TiH_2$ content of 10 and 15 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was heat-treated at $1100^{\circ}C$ for 1 h in a nitrogen and air atmosphere. XRD analysis revealed that the samples composed of TiN and $TiO_2$ phase were dependent on the heat-treatment atmosphere. The sintered samples showed large pores of about 120 mm which were aligned parallel to the camphene growth direction. The internal wall of the large pores had relatively small pores with a dendritic structure due to the growth of camphene dendrite depending on the degree of nucleation and powder rearrangement in the slurry. These results suggest that a porous body with an appropriate microstructure can be successfully fabricated by freeze-drying and a controlled sintering process of a camphene/$TiH_2$ slurry.