• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.384-387
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• 2009

There is an increasing demand for efficient high power/weight auxiliary power supplies for use on high speed traction application. Many new conversion techniques have been proposed to reduce the voltage and current stress of switching components, and the switching losses in the traditional pulse width modulation (PWM) converter. Especially, the phase shift full bridge zero voltage switching PWM techniques are thought must desirable for many applications because this topology permits all switching devices to operate under zero voltage switching(ZVS) by using circuit parasitic components such as leakage inductance of high frequency transformer and power device junction capacitance. The proposed topology is found to have higher efficiency than conventional soft-switching converter. Also it is easily applicable to phase shift full bridge converter by applying an energy recovery snubber consisted of fast recovery diodes and capacitors.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.10-16
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• 1980

Five of each lowland and upland rice varieties were planted in a seedling hox with three replications of randomized complete block design and it was desiccated up to complete water stress in certain leaf stage. The desiccated rice plants were supplied with water again to check survival ability of rice plant from wilting. All of the lowland varieties which showed lower yield in upland condition were superior to upland varieties in recovery ability from desiccation. Some of the morphological characteristics in relation to the recovery ability also were discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.263-269
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• 1997

To cope with increasing importance of water stress in food crop production, some physiological characteristics, their cultivar-differences and grain yield of winter barley cultivars in response to water stress during reproductive stages were studied employing three covered-barley cultivars, Milyang 12, Durubori, and Olbori, one naked-barley cultivar, Baegdong, and one two-row malting-barley cultivar, Hyangmaeg. The barley grown in pot-soil was conditioned for 10 days under water stress, varying the time of water stress : 20 days before heading, 10 days before heading and the time of heading. The decrease in growth due to water stress varied greatly with the cultivars and time of water stress. The greatest injury occurred when water stress was imposed for 10 days from 10 days before heading : the culm length of water-stressed plants have shown reduced by 85∼98％ of the non-stressed; the number of spikes per plant by 52∼83%; the number of grains per spike by 71∼86%; 1,000-grain weight by 80∼84%; yield per pot by 60∼94%. The number of spikes per plant as one of yield components was most sensitively affected. As a whole, the drought resistance of cultivars was high in the order of Olbori> Milyang 12 and Durubori> Hyangmaeg>Baegdong. On rewatering the plants after termination of the water stress treatment the recovery rate of free proline content and relative turgidity of flag leaf were higher in 3 covered-barley cultivars, and lower in cultivars Baegdong and Hyangmaeg.

• Fibers and Polymers
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• v.2 no.3
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• pp.122-128
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• 2001

UV-curable polyurethane acrylate prepolymers were prepared from diisocyanates [isophorone diisocyanate (IPDI), 2,4-toluene diisocyanate (TDI), or 4,4'-dicyclohexylmethane diisocyanate (H$_{12}$MDI)], diols [ethylene glycol (EG), 1,4-butane diol (BD), or 1,6-hexane diol (HD)], polypropylene glycol as a polyol. UY-curable mixtures were formulated from the prepolymer (90 wt%), reactive diluent monomer trimethylol propane triacrylate (10 wt%). and photoinitiator 1-hydroxycy-clohexyl ketone (3 wt% based on prepolymer/diluent). The effects of different diisocyanates/low molecular weigh dial on the dynamic mechanical thermal properties and elastic recovery of UV-cured polyurethane acrylate films were examined. The tensile storage modulus increased a little in the order of EG > BD > HD at the same diisocyanate. Two loss modulus peaks for all samples are observed owing to the glads transition of softs segments ($T_gh$) and the glass transition temperature of hard segments ($T_gh$). For the same diisocyanate, $T_gh$, decreased, however, $T_gh$ increased, in the order of HD > BD > EG. The elastic recovery also increased in the order of HD > BD > EG at the same diisocyanate. In case of same diols, $T_gh$ increased in the order of $H_12$MDl > TDI > IPDI significantly. The ultimate elongation and elastic recovery increased in the order of TDI > IPDI > $H_12$MDl at the same diol.l.

• Tunnel and Underground Space
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• v.24 no.6
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• pp.418-429
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• 2014

Induced seismicity related to four energy development technologies that involve fluid injection or withdrawal: geothermal energy, conventional oil and gas development including enhanced oil recovery (EOR), shale gas recovery, and carbon capture and storage (CCS) is reviewed by literature investigation. The largest induced seismic events reported in the technical literature are associated with projects that did not balance the large volume of fluids injected into, or extracted from the underground reservoir. A statistical observation shows that the net volume of fluid injected and/or extracted may serve as a proxy for changes in subsurface stress conditions and pore pressure, and other factors. Energy technology projects that are designed to maintain a balance between the amount of fluid being injected and the amount of fluid being withdrawn, such as geothermal and most oil and gas development, may produce fewer induced seismic events than technologies that do not maintain fluid balance, such as long-term wastewater disposal wells and CCS projects.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.4
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• pp.776-787
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• 2020

This study investigated physiological and subjective responses to different types of firefighter station uniforms made with various designs and materials. Six healthy males participated in this study that consisted of 20 min of rest, 30 min of treadmill exercise, and 30 min of recovery in a hot and humid environment (34℃ and 65%RH). The experimental clothing conditions were as follows. 1) a fitted T-shirt and trouser made of 100% polyester (FC-Uniform), and 2) flame retardant T-shirts made of acrylic and cotton as well as trousers with aramid and polyester, designed for overfitting (Control). There were no significant differences in the body temperature, and sweat rate between the two conditions; however, the heart rate with the FC-Uniform was significantly lower than Control (p=.025). The clothing microclimate temperature at the chest of the FC-Uniform was significantly lower than the Control (p=.037), and a difference of 1℃ was maintained until the recovery was complete. There were no significant differences in the subjective responses; however, participants experienced a humidity sensation faster with FC-Uniform in the recovery phase. The results indicate that changes in the design and material of firefighter station uniforms may have a positive influence on reducing the thermal stress of firefighters.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.267.1-267.1
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• 2016

본 연구에서는 nematic 액정의 종류 중 하나인 5CB (4-Cyano-4'-pentylbiphenyl) 물질을 박막 트랜지스터 (TFT)의 passivation 층으로 사용했을 때 그 전기적 특성향상을 확인하였다. RF-magnetron sputtering법으로 증착된 비정질 InGaZnO 박막을 활성층으로 사용한 TFT를 제작하여 그 활성층 위에 drop형식으로 passivation 하였다. 그 결과, drain current (I_DS)가 약 10배 정도 증가하고, linear region(V_D=0.5V)에서 mobility와 subthreshold slope(SS)이 각각 6.7에서 12.2, 0.3에서 0.2로 향상되는 것이 보였다. 이것은 gate bias가 인가되었을 때 freedericksz 전이를 통한 액정의 배향과 이때 형성된 dipole 형성에 의한 것으로 보이며, 이러한 LC의 배향은 편광현미경을 통하여 표면과 수직으로 배향한다는 사실을 확인 할 수 있었고 이 LC-passivation된 a-IGZO TFT의 전기적 특성의 향상에 대한 mechanism을 제시하였다. 그리고 배향한 LC가 가지는 dipole에 의해 bias stress 상황에서 독특한 electron trapping과 recovery의 증폭효과가 나타났다. V_G=+20V의 positive gate bias stress를 1000s동안 가했을 때, passivation되지 않은 a-IGZO TFT의 경우 +4V의 threshold voltage shift(${\Delta}V$_TH)가 발생되었고, 바로 -20V의 negative gate bias를 30s간 가해주었을 때 -2.5V의 ${\Delta}V$_TH가 발생하였다. 반면 LC-passivation된 a-IGZO TFT의 경우 각각 +5V와 -4V의 ${\Delta}V$_TH로 더 큰 변화를 가져왔다. 이러한 LC에 의한 electron trapping/recovery 증폭효과에 대한 model을 제시하였다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.341-351
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• 2002

In order to examine the mechanistic basis for differential sensitivities to chilling and subsequent recovery between two rice (Oryza sativa L.) cutivars, a chilling-tolerant japonica type (Ilpumbyeo) and a chilling-susceptible indica type (Taebaekbyeo), changes of physiological responses and antioxidant enzymes were investigated. Both cultivars at 3 leaf stage were exposed at a low temperature of $5^{\circ}C$ for 3 days and subsequently recovered in a growth chamber at a $25^{\circ}C$ for 5 days with 250 mmol $m^{-2}$ $s^{-1}$. Physiological parameters such as leaf fresh weight, relative water content, cellular leakage, lipid peroxidation, and chlorophyll a fluorescence showed that the chilling tolerant cultivar had a high tolerance during chilling. However, the chilling-susceptible cultivar revealed severe chilling damages. The chilling-tolerant cultivar was also faster in recovery than the chilling-susceptible cultivar in all parameters examined. We analyzed the activity and isozyme profiles of four antioxidant enzymes which are: superoxide dismutase (SOD), caltalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR). We observed that chilling-tolerance was due to a result of the induced or higher antioxidant enzyme system, CAT and APX in leaves and SOD, CAT, APX, and GR in roots. Especially, we observed the most significant differences between the chilling-tolerant cultivar and -susceptible cultivar in CAT and APX activity. Also in isozyme profiles, CAT and APX band intensity in the chilling-tolerant cultivar was distinctively higher than in the chilling-susceptible cultivars during chilling and recovery. Thus, the cold stability of CAT and APX are expected to contribute to a tolerance mechanism of chilling in rice plants. In addition, the antioxidative enzymes activity in roots may be more important than in that of leaves to protect chilling damage on rice plants.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.71-78
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• 2005

This paper proposes a novel multi-level energy recovery sustaining driver for AC PDP(Plasma Display Panel), which solves the problems of the conventional multi-level sustaining driver. While the conventional circuit improves the voltage md current stress of the switching elements in Weber circuit not only there are parasitic resonant currents between resonant inductors and parasitic capacitance and hard switching, but also the changing period between 0 and sustain voltage is too long. Comparing the proposed circuit with the conventional circuit, the number of components are reduced and the parasitic resonant currents in resonant inductors are eliminated Moreover the hard switching problem is solved by using CIM(Current Injection Method) and the operating frequency will be high as much as possible by removing Vs/2 sustain period. And the circuit operations of the proposed circuit are analyzed for each mode and the validity is verified by the simulations using PSpice program.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.10
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• pp.1665-1672
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• 2009

This study examines the comfort of outdoorwear by electrocardiogram (ECG) and electroencephalogram (EEG) analyses. An experiment that consisted of rest (30 min), exercise (30 min), and recovery (20 min) periods was administered in a climate chamber with 10 healthy male participants. Two kinds of outdoorwear made of 100% cotton fabrics ('Control') and specially engineered fabrics having the feature of quick sweat absorbency and high speed drying fabric ('Functional') are evaluated in the experiment. ECG and EEG signals were obtained during the rest and recovery periods for the two outdoorwear conditions. The ECG analysis identified a smaller decrement of high frequency (HF) power for the 'Functional' when compared with the 'Control' during the recovery period. Next, the EEG analysis showed that the relative band powers of slow $\alpha$ and mid $\alpha$ increased for the 'Functional' while they decreased for the 'Control' and that the ratio of $\alpha$ power to high $\beta$ power was higher for the 'Functional'. The evaluation results indicate that the participants could remain relaxed more with less stress while wearing the functional outdoorwear that demonstrated the positive effects on autonomic nervous system (ANS) activities. The present study is significant in regard that use of ECG and EEG for the assessment of wear comfort is the first in the field of clothing and textile.