• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.2
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• pp.73-80
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• 2021

Purpose: The purpose of this study is to compare the color stability of provisional restorative materials fabricated by subtractive and additive manufacturing. Materials and Methods: PMMA specimens by subtractive manufacturing and conventional method and bis-acryl specimens by additive manufacturing were fabricated each 20. After immersing specimens in the coffee solution and the wine solution, the color was measured as CIE Lab with a colorimeter weekly for 4 weeks. Color change was calculated and data were analyzed with one-way ANOVA and the Tukey multiple comparisons test (α = 0.05). Results: PMMA provisional prosthetic materials by subtractive manufacturing showed superior color stability compared to bis-acryl provisional prosthetic materials by additive manufacturing (P < 0.05), and showed similar color stability to the PMMA provisional prosthetic materials by conventional method (P > 0.05). Conclusion: It is recommended to fabricate provisional restorations by subtractive manufacturing in areas where esthetics is important, such as anterior teeth, and consideration of the color stability will be required when making provisional prosthetic using additive manufacturing.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.235-240
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• 2021

We present the effect of the critical cooling rate during rapid solidification on the nucleation of precipitates in an Fe₇₅B₁₃P₅Nb₂Hf₁C₄ (at.%) alloy. The thermophysical properties of the rapidly solidified Fe₇₅B₁₃P₅Nb₂Hf₁C₄ liquids, which were obtained at various cooling rates with various sizes of gas-atomized powder during a high-pressure inert gas-atomization process, were evaluated. The cooling rate of the small-particle powder (≤20 ㎛) was 8.4×10⁵ K/s, which was 13.5 times faster than that of the large-particle powder (20 to 45 mm; 6.2×10⁴ K/s) under an atomized temperature. A thermodynamic calculation model used to predict the nucleation of the precipitates was confirmed by the microstructural observation of MC-type carbide in the Fe₇₅B₁₃P₅Nb₂Hf₁C₄ alloy. The primary carbide phase was only formed in the large-particle gas-atomized powder obtained during solidification at a slow cooling rate compared to that of the small-particle powder.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.241-249
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• 2013

This study was aimed to provide the fundamental data about oxidized hair color products. For this reason, we collected 125 oxidized hair color products, which were distributed in domestic market from January to October, 2012, and measured the heavy metal concentrations of lead, arsenic, cadmium, chromium, manganese, nickel, copper in the samples. Results were compared by domestic, foreign, henna, type and color. The average metal concentrations were as follows; 0.211 ${\mu}g/g$ for lead, 0.008 ${\mu}g/g$ for cadmium, 0.051 ${\mu}g/g$ for arsenic, 0.954 ${\mu}g/g$ for chromium, 6.250 ${\mu}g/g$ for manganese, 0.591 ${\mu}g/g$ for nickel and 0.544 ${\mu}g/g$ for copper. In case of lead and arsenic, the concentrations were much less than the regulated amount (20 ${\mu}g/g$ and 10 ${\mu}g/g$, respectively) suggested by MFDS (Ministry of Food and Drug Safety). In henna (p < 0.05), the concentrations were significantly higher than those of other domestic and foreign oxidized hair color products as follows; 1.264 ${\mu}g/g$ for lead, 0.267 ${\mu}g/g$ for arsenic, 0.025 ${\mu}g/g$ for cadmium, 4.055 ${\mu}g/g$ for chromium, 72.044 ${\mu}g/g$ for manganese, 3.076 ${\mu}g/g$ for nickel and 4.640 ${\mu}g/g$ for copper. Statistically, it showed that the heavy metal concentrations were quite different for the different types of hair color products. The cream and liquid type products had the highest average concentration in chromium (0.708 ${\mu}g/g$, 0.478 ${\mu}g/g$, respectively). On the other hand, powder type products showed the highest concentration in manganese (60.041 ${\mu}g/g$). In addition, the concentrations of heavy metals and the color of products are not quite correlated. It was shown that average concentrations of lead and chromium were higher for yellow, chromium for red and pink, manganese for brown and black, and nickel for green.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.12-24
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• 2008

Background: It is currently thought that tissue valve degeneration is related to an animal's immune response, which is mainly due to cell surface ${\alpha}$-Gal epitopes. Cell surface ${\alpha}$-Gal epitopes are known to be degraded by the enzyme called green coffee bean ${\alpha}$-Galactosidase. It is also well known that ${\alpha}$-Gal epitopes are immunologically stained by Griffonia Simplicifolia isolectin type B4. We know that many commercially available tissue valves are made of aortic valves and pericardial tissue of pig. So, we investigated whether ${\alpha}$-Gal epitopes of the aortic valve and pericardial tissue of a pig can be removed by green coffee bean ${\alpha}$-Galactosidase, and we did so by comparing immunologic staining of the tissues before and after the enzyme treatment. Material and method: After treating fresh porcine aortic valve and pericardial tissue with green coffee bean ${\alpha}$-Galactosidase at concentrations of 0.5 unit/mL, 1.0 unit/mL, 2.0 unit/mL, respectively, under the condition of pH 6.5, temperature. $4^{\circ}C$ and 24 hours of incubation, each sample was stained with Griffonia Simplicifolia isolectin type B4 immunpfluorescent labeling. We then examined whether the ${\alpha}$-Gal epitopes were reduced or abolished in each consecutive. concentration of green coffee bean ${\alpha}$-Galactosidase by comparing the degree of the Griffonia Simplicifolia isolectin B4 staining in each sample. Result: In the pig aortic valve tissue, a 1.0 unit/mL concentration of green coffee bean ${\alpha}$-Galactosidase at pH 6.5, $4^{\circ}C$ and reaction for 24 hours was enough for complete removal of ${\alpha}$-Gal epitopes from the cell sur face on the immunostaining with Griffonia Simplicifolia isolectin B4. On the other hand, more ${\alpha}$-Gal epitopes were present in the pig pericardial tissue on Griffonia Simplicifolia isolectin B4 staining before the enzyme treatment, and 1.0 unit/mL of galactosidase was not sufficient for complete removal of ${\alpha}$-Gal from the tissue. 2.0 units/mL of green coffee bean ${\alpha}$-Galactosidase was needed to completely remove the ${\alpha}$-Gal epitopes from the pericardial tissue on immunostaining. Conclusion: The ${\alpha}$-Gal epitopes of the pig's aortic valve and pericardial tissue were successfully stained with Griffonia Simplicifolia isolectin B4. We could remove nearly all the ${\alpha}$-Gal epitopes using green coffee bean ${\alpha}$-Galactosidase at the concentration of 1.0 unit/mL in the aortic valve. Of pig, and 2.0 unit/mL was need to nearly completely remove all the ${\alpha}$-Gal epitopes in the pericardial tissue of pig under the condition of pH 6.5, $4^{\circ}C$ and 24 hours of reaction time. In the near future, removal of ${\alpha}$-Gal epitapes in the pig's aortic valve and pericardial tissue will become a powerful tool for the improvement of the tissue valve durability. It needs to be determined if ${\alpha}$-galactosidase treated pig tissue is immune to human anti-Gal antibody or anit-Gal mooclonal antibodies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1106-1113
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• 2017

The objective of this study was to determine the quality characteristics of fried yakgwa and baked yakgwa prepared with different amounts of P. frutescens powder. Moisture contents of fried yakgwa were 7.05%, and moisture content of baked yakgwa with different amounts of P. frutescens powder were 12.42~10.44% and decreased with higher amount of P. frutescens powder. This result can be attributed to loss of water in yakgwa in the course of the fried process. Although the degree of expansion of baked yakgwa was lower than that of fried yakgwa, size and shape of yakgwa were maintained. Yakgwa is appropriate as a cookie type product. Crude lipid contents of fried yakgwa were higher than those of baked yakgwa due to the exchange reaction of water and fat during the fried process. Energy of fried yakgwa was 501 kcal and was higher than that of baked yakgwa with different amounts of P. frutescens powder. This greatly affected the fat content of each sample. Energy of baked yakgwa increased with higher amount of P. frutescens powder due to the characteristics of the ingredients or jasoyeop. For chromaticity determination, L values of fried yakgwa were lower, but a, and b values were higher than those of baked yakgwa, and L, a, and b values decreased when P. frutescens powder increased. Texture measurement showed that hardness, cohesiveness, chewiness, gumminess increased with higher amounts of P. frutescens powder, whereas springiness decreased. The antioxidant activities of fried yakgwa measured based on DPPH scavenging activity were higher than those of baked yakgwa with 0%~0.2% P. frutescens powder and lower than those of baked yakgwa with 0.3%~0.4% P. frutescens powder. In the sensory evaluation, baked yakgwa with 0.1% addition of P. frutescens powder showed the highest preference in terms of overall acceptance, and 0% addition of P. frutescens powder showed the highest preference in terms of color and flavor. These results suggest that P. frutescens powder may be a useful ingredient in baked yakgwa to improve quality and sensory properties.

• Journal of Life Science
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• v.22 no.3
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• pp.407-416
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• 2012

In this study, we purified the extracts from the seeds and the roots of various plant species, including Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens, and then investigated the effects of these extracts on cell growth and fat accumulation in adipocytes. We found that the extracts purified from Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens more effectively increased the cell growth, as well as promoting the fat accumulation in adipocytes to a greater extent, than other extracts in vitro. Therefore, we made breast packs containing these effective extracts, and then investigated whether they were effective in enhancing the elasticity and volume of women's breasts. The measurements of breast elasticity and size revealed that the breast packs efficiently increased the elasticity and size of women's breasts. Furthermore, evaluation of the questionnaires related to usage of the breast packs indicated great satisfaction in terms of the lift, firmness, and elasticity of breasts. In conclusion, extracts purified from Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens leading to cell growth and fat accumulation in adipocytes can effectively contribute to improving the elasticity and size of women's breasts.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.85-88
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• 2009

Magnetic phases of polycrystalline $Ge_{1-x}Mn_x$ thin films were studied. The $Ge_{1-x}Mn_x$ thin films were grown at $400^{\circ}C$ by using a molecular beam epitaxy. The $Ge_{1-x}Mn_x$thin films were p-type and electrical resistivities were $4.0{\times}10^{-2}{\sim}1.5{\times}10^{-4}ohm-cm$. Based on the analysis of magnetic characteristics and microstructures, it was concluded that the ferromagnetic phase formed on the $Ge_{1-x}Mn_x/SiO_2$/Si(100) thin films was $Ge_3Mn_5$ phase which has about 310 K of Curie temperature. Moreover, the $Ge_{1-x}Mn_x$ thin film which had $Ge_3Mn_5$ phase showed the negative magnetoresistance to be about 9% at 20 K when the magnetic field of 9 T was applied.

• Explosives and Blasting
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• v.28 no.1
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• pp.19-26
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• 2010

The paper presents a case study of a limestone quarry of the Philippines, where major problems in terms of improper fragmentation, poor wall control, and poor heave of the muck pile were witnessed. The paper highlights the significant role of switching over from diagonal firing pattern to V-type firing pattern, and also of making suitable adjustments in the stemming column length for improved confinement and gas retention. The study revealed that by making aforesaid design modifications in the blast round, marked improvement in blasting results was registered. Looking at the results, it was further contemplated to expand the mesh area in the subsequent blast rounds. The mesh area was incremented from the existing $8.96m^2$ to $12m^2$. The results were meticulously registered in the field, and clearly depicted definite improvements in the blast results in terms of increased P.F., reduced boulder count, reduced FEL cycle time, reduced dozing hours and improved heave.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.1-7
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• 2010

The paper proposes a multi-body dynamic simulation to numerically evaluate the generated axial force(G.A.F) and plunging resistant force(P.R.F) practically related to the shudder and idling vibration of an automobile. A numerical analysis of two plunging types of CV joints, tripod joint(TJ) and very low axial tripod joint(VTJ), is conducted using the commercial program DAFUL. User-defined subroutines of a friction model illustrating the contacted parts of the outboard and inboard joint are subsequently developed to overcome the numerical instability and improve the solution performance. The Coulomb friction effect is applied to describe the contact models of the lubricated parts in the rolling and sliding mechanisms. The numerical results, in accordance with the joint articulation angle variation, are validated with experimentation. The offset between spider and tulip housing is demonstrated to be the critical role in producing the 3rd order component of the axial force that potentially causes the noise and vibration in vehicle. The VTJ shows an excellent behavior for the shudder when compared with TJ. In addition, a flexible nonlinear contact analysis coupled with rigid multi-body dynamics is also performed to show the dynamic strength characteristics of the rollers, housing, and spider.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.590-596
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• 2020

The fabric used for military winter inner clothing(top) is quilted with padded cotton to provide warmth. This quilting fabric is generally manufactured with yarns that intersect and are sewn substantially between the fabric and cotton. Thus, it is impossible to separate the fabric and cotton once after the quilting fabric is manufactured, which can result in a significant loss of fabric and cotton when separated. In this study, after fabricating the quilting fabric, we investigated a method to stabilize change rate of thickness and increase the warmth keeping property through subsequent processing without damaging the fabric. A relatively method of passing the quilting fabric through a part of the cotton production facility was used generally, and the following results were obtained. This indicates that after the quilting fabric was manufactured, the warmth keeping property was improved through the subsequent processing steps, so that the change rate of thickness due to washing was stabilized.