• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.732-737
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• 2005

Distal 3D Real Object Duplication System(RODS) consists of 3D Scanner and Solid Freeform Fabrication System(SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and a industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer(SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. Also, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Multi-Laser Sintering(SMLS) process and 3-axis dynamic Focusing Scanner for scanning large area instead of the existing $f\theta$ lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, scan spacing. Now, this study is in progress to eveluate the effect of experimental parameters on the sintering process.

• Journal of Sericultural and Entomological Science
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• v.17 no.1
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• pp.55-62
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• 1975

In the studies of characterization of crystal prototoxin isolated from Bacillus thuringinensis var. alesti and its bioassay to the silkworm larvae, Bombyx mori L., the following results were obtained. 1. The complete lysis of bacteria grown on the nutrient agar at 30$^{\circ}C$ in an incubator took 30 days, but the period could be reduced by a half in a devised broth media in a fermentation jar. 2. The protein toxin extracted directly from a mixture of crystals and spores without separation of crystals and spores was pure as same as the protein toxin extracted from only crysals separated. 3. By SLS polyacrylamide gel electrophoresis of prototoxin released from crystals in alkali (pH 9.5) three different proteins in molecular weights of 120,000, 87,000, 74,000 were separated. 4. In the bioassay of the toxin to the silkworm larvae, LD$\sub$50/ per gram of the larvae in the 4th instar was 0.080 $\mu\textrm{g}$.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.286-294
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• 1989

This Study has treated the effects of fiber, surfactants, temperature, surfactant concentration, pH, electrolyte, fatty acid contents and mechanical force on the removal of particulate soil from fabric, vacuum cleaner dirt was used as model particulate soil. The fabrics were soiled with mixture of vacuum cleaner dirt and fatty soil, and washed in Terg-O-tometer. The detergency was evaluated by measuring reflectance of a fabric before and after washing. The results were as follows. 1. The fiber type showed a different pattern of soil removal with surfactants. In general, particulate soil removal increased in the following order Acetate>PET. Nylon>Cotton. Particulate soil removal, which is affected by the surfactant type, increased in the following order NPE $(EO)_{10}\leqq$Soap>SLS>DBS>Tween 80. 2. The influence of temperature on the particulate soil removal was very complex because efficiency of removal was varied with surfactant and fiber types. The washing efficiency of NPE $(EO)_{10}$ was highest at around $40^{\circ}C\;and\;60^{\circ}C$ with cotton and PET but the washing efficiency of DBS was the highest at $60^{\circ}C$ with cotton, decreased monotonously with increasing temperature with PET 3. The detergency of particulate soil increased with increasing surfactant concentration at relatively low concentration and then levelled off above some optimum concentration. 4. The removal of particulate soil increased with increasing pH and mechanical force. 5. Effect of electrolyte on the particulate soil removal was depended on the concentration of the surfactant. At low concentration of surfactant, addition of electrolytes improved soil removal but above the some concentration no effect was observed. At high concentration of surfactant, Vie., $0.6\%$ , the maximum washing effect is reached without added electrolyte. These result indicate that added electrolyte only influence the adsorption of surfactant on the soil and fiber 6. Fatty acid content in the soil did not influence on particulate soil removal without regard to surfactants.

• Health Policy and Management
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• v.14 no.4
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• pp.48-74
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• 2004

Considering the existence of asymmetric information between doctor and patient, the doctor's reimbursement method has been considered as a desirable policy device of improving efficiency of patient's use of medical care in terms of its affecting doctor's practice pattern by determining doctor's practice revenue. By using the Community Tracking Study (CTS) physician data set, which includes not only various information on doctors practice arrangements and sources of practice revenue, but also vignettes of various clinical presentations, this paper investigates doctor's reaction to the financial incentive under the control of patient's specific medical situation. Under the econometric model for exploring the effect of doctor's reimbursement method on his/her practice patterns; referring patients, recommend doctor-visit or medical tests, the Hausman's specification test was used for checking out the possibility of the doctor's reimbursement method being endogeneized explanatory variable. In the case where the endogeneity problem of doctor's reimbursement method exists, the 2SLS method was used for correcting that problem, and the multiple regression method was used in the case where the problem is found to be nonexistent. Based on the empirical results, this paper finds that doctors do appear to respond to financial incentive. The empirical results show that the doctor's reimbursement method statistically significantly affects doctor's practice pattern and are coincident with the theoretical result proposed by previous researches, This results suggest, as doctor's practice revenues are mainly determined by prospective method, such as capitation, doctors would more refer their patients to specialists, and hesitate in recommending doctor-visit or medical exam.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.191-197
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• 2002

Polymer based physical mixtures or solid dispersions containing solubilizing compositions[OA, tween80 and SLS] were prepared using a spray-dryer. Lovastatin(LOS), simvastatin(SIMS), aceclofenac(AFC) and cisapride(CSP) were selected as poorly water-soluble drugs. Dextrin, poly(vinylalcohol) (PVA), poly(vinylpyrrolidone)(PVP) and polyethylene glycol(PEG) were chosen as solubilizing carriers for solid dispersions. The solid dispersions containing solubilizing compositions without drug were prepared without using organic solvents or tedious changes of formulation compositions. This system could be used to quickly screen the dissolution profiles of poorly water-soluble drugs by simply mixing with drugs thereafter. In case of solid dispersion containing drug, organic solvent systems could be used to solubilize model drugs. The dissolution rates of the drugs were higher when mixed with drug and solid dispersions containing solubilizing compositions. However, solid dispersions of LOS, AFC, and CSP simultaneously containing drug and solubilizing compositions in organic solvent systems were more useful than physical mixtures of drug and solid dispersions without drug except SIMS. Based on solubilizing capability of polymer based physical mixtures in gelatin hard capsules, optimal solid dispersion system of poorly water-soluble drugs could be formulated. However, it should be noted that dissolution rate of poorly water-soluble drugs were highly dependent on drug properties, solubilizing compositions and polymeric carriers.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.434-445
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• 2018

This study examined whether mobile OTT video service substitutes home TV by using 3 screen data of Nielson-KoreanClick. According to the 2SLS estimation results, when the time spent on mobile OTT video service increased by 1% p, the time spent watching home TV decreased by 12.4%. The results also showed that 1%p increase in the time spent using YouTube app and the mobile OTT video services provided by telecommunication company(Oksusu, Alleh TV, VideoPortal) reduced the time spent on watching terrestrial channels on TV by 16.2% and 23.9%, respectively. The displacement of mobile OTT video service on home TV will be accelerated in the near future. In order to resolve the issue of regulatory unfairness with pay TV services and to safeguard viewer's interests, discussions to establish regulation for OTT video services should be taken place more quickly.

• Environmental Analysis Health and Toxicology
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• v.7 no.1_2
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• pp.67-87
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• 1992

Each detergent-solution in the concentration of 0.4% was prepared with four kinds of raw materials of detergents and two kinds of commercial surfactants for kitchen. LAS (Linear Alkyl Benzene Sulfonate), AOS ($\alpha$-O1effine Sulfonate), SLS (Sodium Lauryl Sulfonate) and SLE (Sodium Lauryl Ester Sulfonate) were used as the raw materials. Vegetables and fruits such as cucumber, crown daisy, lettuce, strawberry and tomatos were diped in each solution and washed 5 times in static or flow state. For the other experiments, tablewares such as porcelain, stainless bowls, glass and plastic cups were diped in each solution and washed also 5 times with cold and hot water in static or flow state. The residues of the detergents on the every steps of wash-conditions were measured. The results of this study were summarized as followings: 1. The residures of the detergents on the tested vegetables and fruits after 5 times washing were detected with the range from 0.450 to 7.120 ppm in static state and from 0.343 to 6.375 ppm in flow state. 2. The residures of the detergents on the tested tablewares after 5 times washing with cold water were observed with the range from 0.057 to 0.815 ppm in static state and from 0.066 to 0.905 ppm in flow state. 4. The residures of the detergents on the tested tablewares after 5 times washing with hot water were determined with the range from 0.061 to 0.424 ppm in static state and from 0.066 to 0.368 ppm in flow state. 4. Independent on detergent types, water temperatures and washing methods, the detergents were remained stablely on the porcelain; 0.057~0.815 ppm, on the stainless bowl; 0.061~0.905 ppm, on the glass cup; 0.0l4~0.592 ppm and on the plastic cup; 0.201~0.592 ppm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.611-620
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• 2016

Firms grow in a competitive environment and competition can be a source of corporate growth. In an increasingly global market, companies face increased competition. As such, it is natural that all firms face some degree of risk due to competition. While firms compete for market share, they also imitate competitors in order to minimize risk that accompanies competition. This research attempts to demonstrate the effects of inter-firm competition on investment decisions. Using idiosyncratic equity returns as the instrument variable, this paper uses a two-stage least squares regression, as well as an ordinary least squares (OLS), to identify the influence of peer firms' investment decisions on a firm's own investment strategy. The results confirm that firms show stronger imitative behavior with more intense competition. Also, firms with higher debt ratios show higher peer group influence. This imitative factor provides clues to measure the risk-averseness in investment decisions.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.4
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• pp.317-323
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• 2008

Some surfactants known as biosurfactants, are produced biologically by yeast and bacteria from various substances. They are more effective and environmentally friendly than many other synthetic surfactants. Antimicrobial activities of sophorolipids produced by Candida bombiocola were investigated against various microorganisms. Minimal Inhibitory concentration (MIC) of sophorolipid against S. mutans, C. xerosis, and P. acnes were 0.005, 0.05, and 0.005%, respectively. The antimicrobiological activities were more effective than those of SLS and APG. Skin exfoliating and moisturizing effects of vehicles with the sophorolipids were tested. The skin turnover time of aqueous solution with 0.25% sophorolipids was similar to that of aqueous solution with 5.0% lactic acid. Higher moisturizing effects on skin showed as the concentration of sophorolipids increased. We suggest that the sophorolipids can be used for cosmetics as an antimicrobiological agent and an active materials of skin moisturizing and exfoliating.

• Korean Journal of Microbiology
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• v.13 no.3
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• pp.109-115
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• 1975

DNA's were extracted from Saccharomyces cerevisiae and Mycobacterium phlei and the damaging cell walls of these microoragnisms were examined under an electron microscope in the extraction process in which a number of physico-chemical tratments of cells was involved. While the DNA was easily extracted from S. cerevisiae using conventional meylelded very little DNA, of M. phlei was extremely difficult to isolate and yielded very little DNA, applying various methods of isolation published earlier. When the cell walls of S. cerevisiae were examined with the electron microscope, they were not yet damaged even after the cells were treated with sodium lauryl sulfate(SLS) and ethylene diamine tetracetic acid(EDTA), but they were completely destroyed by the treatment of sodium perchlorate followed by the addition of chloroform and a vigorous agitation. Oozing cytoplasm through the broken cell walls was also observed. In the extraction of DNA from M.phlei, the pronase was not effective at the aerobic environment of the sample. When phenol was applied at the last step of DNA isolation, an extreme damage mass yielding little DNA into the solution. Unlike the cells of S.cerevisiae.M.phlei cells showed a tendency of aggregation, thus the destruction of cell walls by sodium hydroxide was seen only on the walls of peripheral cells in the aggregated mass, leaving the walls of the inner cells undamaged.