• Fibers and Polymers
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• v.7 no.4
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• pp.352-357
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• 2006

The cotton fabrics were pretreated by sodium 2-(2,3-dibromopropionylamino)-5-(4,6-dichloro-1,3,5-triazinylamino) benzenesulfonate (DBDCBS) at alkaline condition ofroom temperature and then dyed with four disperse dyes having amino groups (C.I. Disperse Yellow 9, C.I. Disperse Red 11, C.I. Disperse Blue 56 and C.I. Disperse Violet 1) at acidic condition of high temperature. A novel hetero-bifunctional bridge compound, DBDCBS, has two reactive groups such as dichloro-striazinyl group and ${\alpha},\;{\beta}$-dibromopropionylamido group. The first has reactivity towards hydroxy group of cellulosic fiber and the second shows reactivity towards amino groups of disperse dye containing amino groups. The results indicate that it is possible to dye polyester/cotton blend at one-bath dyeing using one kind of disperse dye containing amino groups. Therefore, two kinds of dyeing methods such as two-bath process one-bath dyeing and one-bath process one-bath dyeing were investigated and their dyeabilities were compared. The differences between these two methods were negligibly small so that perfect one-bath one-step dyeing of polyester/cotton blend by one kind of disperse dye was achieved.

• Journal of Families and Better Life
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• v.23 no.2 s.74
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• pp.63-76
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• 2005

Health is the most important factor in the Quality of life. Without appropriate treatment, dental caries could have serious effects on self-esteem, nutrition, and health of a person throughout his/her life. The purpose of this study was to investigate ways to develop a consumer information program that could help improve teens' oral health. To develop an effective information program, we surveyed 1) how teens feel about oral health information in the market, 2) how judiciously they use their information, and 3) how they actually apply the information to practice. On the other hand, we investigated relationships between dietary patterns and dental caries among middle school students. The results indicate a serious lack of oral health information for middle school students. Moreover, we found that the intake of vegetables, fruits and legumes prevents dental caries. Using these results, we developed a system for organizing and conveying the oral health information for teens.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.209-212
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• 2009

It has been widely reported that carbide-free bainitic steels or super-bainite WP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in the SB-TRIP steel.

• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.95-101
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• 2009

In this study, we assessed the effects of Se-methylselenocysteine (MSC) pretreatment on the antioxidant system in the pancreas and the development of alloxan-induced diabetes in rats. The rats were treated with MSC at a dose of 0.75 mg/rat/day for 2 weeks. The MSC-treated rats evidenced significantly increased glutathione content, GSH/GSSG ratio, and glutathione peroxidase (GPx) and glutathione reductase (GRd) activities in the pancreas. Diabetes was induced via alloxan injection. The alloxan-diabetic rats evidenced significantly reduced glutathione content and glucose 6-phosphate dehydrogenase (G6PD) activity and increased catalase activity in the pancreas, when measured 3 days after the alloxan injection. 2-week MSC pretreatment was shown to prevent the alloxan-induced hyperglycemia as well as changes in glutathione content, G6PD activity, and catalase activity. The results of this study indicate that the prevention of alloxan-diabetes by MSC pretreatment is associated with its effects on antioxidants in the pancreas, namely, the increase in cellular content and the reduction of glutathione by the facilitation of glutathione recycling induced via increased GPx, GRd, and G6PD activities.

• Journal of Ginseng Research
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• v.27 no.1
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• pp.11-16
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• 2003

In this study, we investgated the effect of Red Ginseng (KRG) on liver damage induced by carbon tetrachloride (CTC) and galactosamine (GalN) in rats using indicator enzymes such as serum alanine/aspartate aminotransferases, sorbital dehydrogenase, lactate dehydrogenase, and ${\gamma}$-glutamyltransferase. Treatment of KRG restored these enzyme activities to near normal level compared to CTC or GalN treatment alone. Treatment of KRG also enhanced hepatic microsomal enzyme system, malondialdehyde formation, and depletion of reduced glutathione content, which were reduced by CTC or GalN. We also found that the decreased activities of glutathione S-transferase and glutathine reductase but not ${\gamma}$-glutamycysteine synthetase after KRG treatment restored to normal level. These results indicate that KRG has potent therapeutic activity against CTC- and GalN-induced hepatotoxicity in rat.

• Journal of the Ergonomics Society of Korea
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• v.26 no.1
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• pp.29-37
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• 2007

This study was performed to evaluate the characteristics of transmitted vibration to hand-arm system under different work posture while operating a light-weighted powered hand grinder. For the experiment, 8 different types of wrist posture (natural, unlar-flexion, radual-flexion, flexion, extension, complex posture, and etc.) and 3 types of feed force (20[N], 50[N], 70[N]) were considered. 10 male subjects were employed to polish metal plate with a hand grinder. All of them were normal and healthy with no history and symptom of the work related musculoskeletal disorders in the dominant hand. Vibration acceleration data were recorded with sampling rate, 2048[Hz]. In addition, unweighted overall R.M.S. acceleration at the tool and wrist, and transmissibility between them were used to evaluate factors from the recorded tri-axial vibration acceleration. The results indicate that transmissibility of natural wrist posture was significantly higher than others. In addition, as the feed force becomes larger, the vibration was transmitted in large quantities to hand-arm system through radius.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.5
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• pp.433-442
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• 2012

The influence of outdoor sky conditions on photosensor signals were examined to determine an appropriate index that is effectively used for optimum illuminance fluctuation when a daylight dimming system is used for a small office. Field measurements were conducted under various sky conditions. Results indicate that the outdoor global and vertical illuminance fluctuated within narrow ranges under clear and overcast sky conditions. The fluctuation of sky ratio under partly-cloudy sky caused wide ranges of illumnance fluctuation. A partially-shielded photosensor at backwall produced 56% of light output from fixtures controlled by a photosensor at ceiling. This implies that the photosensor at backwall does not always guarantee target illuminance due to the less output. The fluctuation of light output from fixtures were insignificant under clear and overcast sky. The fluctuation range of photosensor illuminance under partly-cloudy sky caused wide fluctuation ranges of light output. Regression result implies that the outdoor vertical illuminance was recommended for an effective index that is used for control of light output.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.18-31
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• 2000

A stack must be designed to 1) reduce or eliminate rainfall or snowfall into a industrial exhaust system, 2) minimize a resistance to flow, 3) maximize the vertical dispersion of the contaminated air and 4) minimize maintenance. The weather cone stacks and the elbow-type stacks are very popular in Korea. But they add some resistance to the exhaust system resulting in reduction of air flow rate, but also deflect the noxious contaminants downward in undiluted form. To solve these problems, ACGIH (American Conference of Governmental Industrial Hygienists) suggested the vertical discharge stack with concentric space between the upper stack with larger diameter and the lower stack with smaller diameter. The preliminary test showed that the vertical discharge stacks did not have the good rainfall protection. The reversed cone were newly devised to satisfy the requirements for the good stack. Subsequently, the amount of rain being penetrated through the stacks was measured while the stacks were simultaneously and naturally exposed to rain in the same area outside. Test results indicate that none of the stacks tested completely exclude rain. The efficiency of rainfall protection and the pressure loss coefficient were compared. The temporary conclusion was reached to the point that the reversed cone stack is the best one. Further research is underway.

• Structural Engineering and Mechanics
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• v.48 no.1
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• pp.1-16
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• 2013

The seismic response of RC space frame structures with isolated footing resting on a shallow soil stratum on rock is presented in this paper. Homogeneous soil stratum of different stiffness in the very soft to stiff range is considered. Soil, footing and super structure are considered to be the parts of an integral system. A finite element model of the integrated system is developed and subjected to scaled acceleration time histories recorded during two different real earthquakes. Dynamic analysis is performed using mode superposition method of transient analysis. A parametric study is conducted to investigate the effect of flexibility of soil in the dynamic behaviour of low-rise building frames. The time histories and Fourier spectra of roof displacement, base shear and structural response quantities of the space frame on compliant base are presented and compared with the fixed base condition. Results indicate that the incorporation of soil flexibility is required for the realistic estimate of structural seismic response especially for single storey structures resting on very soft soil.

• Journal of Power Electronics
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• v.12 no.1
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• pp.145-156
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• 2012

These days, the application of electronic power transformers (EPTs) is expanding in place of ordinary power transformers. These transformers can transmit power via three or four wire converters. Their dynamic performance is extremely important, due to their complex structure. In this paper, a new method is proposed for improving the dynamic performance of distribution electronic power transformers (DEPT) by using sliding mode control (SMC). Hence, to express the dynamic characteristics of a system, different factors such as the voltage unbalance, voltage sag, voltage harmonics and voltage flicker in the system primary side are considered. The four controlling aims of the improvement in dynamic performance include: 1) maintaining the input currents so that they are in sinusoidal form and in phase with the input voltages so they have a unity power factor, 2) keeping the dc-link voltage within the reference amount, 3) keeping the output voltages at a fixed amount and 4) keeping the output voltages in sinusoidal and symmetrical forms. Simulation results indicate the potential and capability of the proposed method in improving DEPT behavior.