• Korean Journal of Materials Research
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• v.29 no.5
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• pp.277-281
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• 2019

The objective of this research is to evaluate the effect of adhesive types on dimensional stability of bamboo-oriented particleboard. The materials used in this research are bamboo tali(Gigantochloa apus J.A & J.H. Schult. Kurz), UF/MDI(8, 10, 12 % level), and MF, MDI, and PF at 7 % level. Particle and adhesive are mixed using a blending machine; then, mat forming and hot pressing processes are performed using adhesive-suitable temperature and time references. MDI resin is set at $160^{\circ}C$ temperature for 5 minutes. PF resin and MF resin are pressed at $170^{\circ}C$ for 10 minutes, and $140^{\circ}C$ for 10 minutes, respectively, while UF/MDI sets at temperature of $140^{\circ}C$ for 10 minutes. The results show that particleboard using PF resin produces the lowest thickness swelling value. The particleboard using UF/MDI resin also produces good response for thickness swelling value. Interesting things happen in that UF/MDI adhesive produces a thickness swelling value better than that of MDI resin. FTIR analysis on particleboard bonded by UF/MDI resin combination shows the presence of carbonyl group C=O vibration on multi substitution of urea at wave number of around $1,700cm^{-1}$.

• Transactions of Materials Processing
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• v.30 no.1
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• pp.35-42
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• 2021

Magnesium alloys are used in electronic devices such as laptops due to their lightweight features as well as vibration absorption and electromagnetic shielding properties. However, the precision of electronics is limited by the large number of small and precise ribs, the cost-effective manufacture of which requires appropriate technology. Plate forging is an efficient manufacturing process that can address these challenges. In this study, plate forging of magnesium alloys was investigated specifically for the fabrication of laptop cover. The plate forging process with back-pressure was used for near-net shape formation. Finite element analysis was used to select appropriate variables for back-pressure formation to generate ribs of various sizes and shapes without defects. The reliability of the analysis was verified to manufacture the prototype. The effect of back-pressure can be verified via fabrication of prototypes as well as structure and forming analysis based on finite element method. The process design factor of back-pressure increases formability without defects of under-filling and flow-through. Moreover, the tensile strength was maintained even after high temperature plate forging at 370 ℃, and the elongation was improved.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.39.1-39.1
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• 2019

We trace the cosmological origin of satellites around isolated dwarf galaxies using a very high resolution (12 pc/h) cosmological hydrodynamic zoom simulation. To realistically describe the formation and evolution of small-mass stellar satellites, our model includes a full baryonic physics treatment. We find that the mini-halos form objects resembling dwarf galaxies. The majority of their star forming gas is accreted after reionization, thus the survival of a mini-halo's gas to reionization is not an important factor. Instead, the key factor seems to be the ability for a mini-halo to cool its recently accreted gas, which is more efficient in more massive halos. Although the host galaxy is only a dwarf galaxy itself, we find that ram pressure is an efficient means by which accreted mini-halos lose their gas content, both by interacting with hot halo gas but also in direct collisions with the gas disk of the host. The satellites are also disrupted by the tidal forces near the center of the host galaxy. Compared to the disrupted satellites, surviving satellites are relatively more massive, but tend to infall later into the host galaxy, thus reducing the time they are subjected to destructive environmental mechanisms and dynamical friction.

• International Journal of Advanced Culture Technology
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• v.12 no.1
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• pp.1-10
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• 2024

While technologies such as the 4th revolution and artificial intelligence (AI), which create new value through the convergence of intelligent information technology, are becoming hot topics, the beauty industry is rapidly developing and combining information and communication technology to produce beauty items based on smartphones among mobile technologies. As the area of expands, YouTube is forming a network through various means of information. In particular, beauty-related YouTube videos are a field of great interest and popularity among the public. By classifying the makeup characteristics according to the emotional images shown in domestic YouTube videos by emotional image and identifying the characteristics of makeup, the needs for watching YouTube makeup videos are identified. We aim to build trust in the delivery of information about makeup. The emotional images were divided into four types: 'modern', 'natural', 'gorgeous', and cute. Among the domestic makeup YouTubers, Pony, Isabe and Shinnim, Lamuque were selected. By organizing more diverse makeup-related content systematically and creatively, we expect to have a positive influence on k-makeup not only domestically but also overseas. We aim to provide basic data for follow-up research on makeup YouTuber videos in the field of cosmetology and contribute to marketing plans for the development of the beauty content industry and establishment of promotional strategies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.824-831
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• 2009

In order to investigate the quality characteristics of powdered teas using Compositae species flower, the samples of Chrysanthemum indicum L. (CI), Chrysanthemum boreale Makino (CB), and Chrysanthemum zawadskii var. latilobum (Maxim.) Kitam (CZ) were extracted with hot water and concentrated, and then mixed with different forming agents of dextrin (D) and maltodextrin (MD). The mixing ratio of D and MD was ranged from 9:1 (DMD91) to 8:2 (DMD82) or D and MD only. The solubility of the powdered tea was higher in added dextrin. The highest total polyphenol and flavonoid content of the powdered tea were 6.75 and 3.24 mg/g at CBDMD91, respectively. Total antioxidant activities of C. indicum, C. boreale, and C. zawadskii powdered tea ranged at $2.51{\sim}2.63$, $4.37{\sim}4.50$, and $3.44{\sim}3.55\;mg$ AA eq/g, respectively. In sensory evaluation, the C. indicum and C. zawadskii powdered teas obtained higher sensory score of all evaluation items than C. boreale powdered tea. The optimal mixing ratio at 36% of D and 4% of MD in forming agent was selected to enhance the sensory characteristics and antioxidant activities of powdered tea.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.180-188
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• 1982

This study was carried out to make hardboard fire retardants and to examine the properties of the hard-board treated with them. The fire retardant treatment was achieved by surface impregnation of water soluble retardant chemicals into the forming mat with 55 percent of moisture content. followed by the hot pressing process. Ammonium monophosphate, ammonium diphosphate, sodium borate, and boric acid were used as the fire retardants. Fire retardant test was carried out by using the differential thermal analysis thermogram. The results are summarized as follows: 1. Fire retardant-treated hardboard showed higher values of the specific gravity. water absoption, and flexural strength than those of untreated hardboard. Especially, the treatment of ammonium monophosphate gave the best results in the flexural strength, and a 10 gr/$ft^2$ loading of the fire retardant compound of ammonium monophoshate, ammonium diphosphate, and sodium borate drew the best flexural strength value among the three different experimental loadings of 10, 20 and 30 gr/$ft^2$. 2. There were no definite differences in moisture content between the fire retardant-treated hardboard and the untreated hardboard. 3. The fire retardant compound of ammonium monophosphate, ammonium diphosphate, and sodium borate resulted in the best fire retardancy, and its fire retardancy was increased in proportion to the increase of loading.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.323-329
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• 2007

We investigated the immunomodulatory actions of water extract from Acanthopanax senticosus in male ICR mice. The mice were treated with fermented milk containing three added doses of freeze dried extract: 3 mg/kg (A), 9 mg/kg (B), and 27 mg/kg (C) of body weight with Acanthopanax senticosus: Codonopsis lanceolata (8:2) for 7 and 10 weeks, respectively. Organ weights, plaque-forming cell tests, agglutination tests, IgG tests, differential white cell counts, and histological tests were performed at the 7th and 10th weeks of dietary treatment. There were no significant differences in body weight and organ weight. The spleen indices of group B at 7 weeks and group C at 10 weeks were significantly higher than those of the control group (p<0.05). For the plaque-forming cell test, groups B and C at 7 weeks, and group C at 10 weeks, showed significant increases over the control group (p<0.05). The agglutination test decreased with an extended experimental period. Groups A, B, and C at 7 weeks, and groups B and C at 10 weeks, had greater antibody responses to sheep red blood cells (SRBC) than the control group. The IgG antibody production of group C at 7 weeks and groups B and C at 10 weeks were significantly higher than the control group (p<0.05). In groups B and C, lymphocyte percentage was higher than the control group, and their spleen and thymus tissues showed active immune reactions.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.1-8
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• 1988

The physicochemical properties and gel-forming properties of corn & red bean crude starches were investigated. The results were as follows: 1. The shape of corn crude starch granule was polygonal and the mean value of minor axis and major axis were $11.5\mu\textrm{m}$ and $14.9\mu\textrm{m}$, respectively. In the meantime, the shape of red bean crude starch granule was oval and the mean value of minor axis and major axis were $22.3\mu\textrm{m}$ and $31.4\mu\textrm{m}$. 2. Amylose content of corn and red bean refined starch were 16.52 and 43.61% respectively. 3. Blue value of corn and red bean crude starch were 0.099 and 0.842, respectively. 4. Amylose of corn had molecular weight of 107,000 and degree of polymerization of 660. Amylopectin had degree of branching of 6.9 per 100 glucose units and glucose units of 14.6 persegment of amylopectin. Amylose of red bean had molecular weight of 118,000 and amylopectin had degree of branching of 5.2. 5. Water binding capacities of corn and red bean starch were 238.5 and 284.8. 6. Both swelling powers of corn and red bean starch were increased rapidly from $70^{\circ}C$ to $90^{\circ}C$. 7, Gelatinization of corn and red bean were 75.6 and $61.8^{\circ}C$. 8. Brabender hot-paste viscosities of corn at 6% and 8% showed the similar amylogrm patterns with peak viscosity. And red bean had no peak viscosity. 9. The difference of sensory characteristics for ‘Mook’ and kidney bean & red bean starch gels was significant.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.511-518
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• 1998

Anti-complementary assay for immuno-stimulating polysaccharide screening, human tumor colony-forming assay for discovering anti-tumor drugs, and toxic assay against mouse were performed to examine pharmacological activities of polysaccharides extracted from fruiting bodies of Jang-soo mushroom (Fomitella fraxinea). Hot water $(100^{\circ}C,\;FF-I)$, 1% ammonium oxalate solution $(80^{\circ}C,\;FF-II)$, and 5% sodium hydroxide solution $(80^{\circ}C,\;FF-III)$ were used for extraction of three polysaccharides from fruiting bodies of it. Anti-complementary activity of FF-I was more effective than the others. FF-I was further fractionated into three groups of polysaccharide by DEAE-Sephadex A25 column chromatography (FF-NP, FF-AP1, and FF-AP2). FF-AP1 showed not only the highest anti-complementary activity but also the growth-inhibitory activity against Snu-I (human stomach cancer cell) among 9 kinds of human tumor cell lines. But FF-AP2 exhibited its activity against Hep-2(larynx cancer) and KB(mouth epidermal cancer) cell lines at $500\;{\mu}g/ml$ although its anti-complementary activity was lower than it of FF-AP1. When FF-I was orally administrated to mice with dosage of 5000 mg/kg, no remarkable changes were observed in viewpoint of tissue-pathology.

• The Korean Journal of Mycology
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• v.13 no.3
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• pp.131-139
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• 1985

To find antitumor constituents in the shake cultured mycelia of Agaricus campestris, the mycelia were extracted with hot water. Purification of the extract was carried out by ethanol precipitation and by ion exchange chromatography using DEAE-Sephadex A-50. Each fraction obtained during the purification procedure was examined for antitumor activity against sarcoma 180 in ICR mice. The antitumor fraction C was isolated. It showed 56.1% inhibition ratio at a dose of 20 mg/kg/day and consisted of a polysaccharide moiety (45%) and a protein moiety (18%). The polysaccharide was analyzed by G.L.C. and found to contain mannose (42.0%), glucose (25.5%), xylose (16.6%), fucose and galactose. The protein moiety was composed of 17 amino acids. The antitumor fraction A showed immunopotentiating activity by accumulating peritoneal macrophages and by increasing plaque-forming cells in mice.