• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.184-187
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• 2009

In this paper, we study effect of charge balance on performance of blue phosphorescent organic light emitting diodes (OLEDs). Charge balance determines the location of recombination zone in the OLEDs. By tuning the charge balance in iridium (III) bis[(4,6-difluorophenyl)-pyridinate-N,C2']picolinate (FIrpic) based blue phosphorescent organic light-emitting devices (PHOLEDs) with a high mobility and high triplet energy electron transporting material, we were able to achieve a high current efficiency of 60 cd/A which is a 3X improvement over previous devices with 3,5'-N,N'-dicarbazole-benzene (mCP) host.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.3-6
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• 2004

반도체 디자인, 공정 기술 및 패기지 기술의 발달에 따라 전력용 반도체는 소형화, 고성능화, 지능화하고 있다. 고속 구동이 용이한 때문에 MOSFET이나 IGBT등의 MOS-gate형 전력 반도체의 발전이 두드려지며, trench, charge balance, NPT 기술등이 패키지 기술과 더불어 이를 위한 주요 기술이 될것으로 보인다. SiC나 GaN등의 Wide Band Gap 물질들을 사용한 차세대 전력 반도체 연구도 활발히 진행되고 있다.

• 유기물자원화
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• 제29권4호
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• pp.77-86
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• 2021

본 연구에서는 유기성폐자원에너지 인센티브제도의 기초자료로 활용하고자 음식물폐기물, 음폐수 및 다양한 유기성폐기물이 처리되는 혐기소화조의 운영방식의 물질수지와 에너지수지 산정 결과를 통하여 에너지효율을 평가하고자 한다. 바이오가스화 시설 11개소의 물질수지 분석 결과 유기성폐기물을 제외한 반입물 중 공정수 21.1%, 시상수 25.7 % 다량 투입되는 것을 확인하였다. 그에 따라 연계처리수의 전체 유출물의 87.6 %를 차지하였다. 또한 총 유입물량의 15.7 %가 바이오가스로 전환되며, 총고형물(TS)가 평균 22 %임을 감안할 때 평균 75 %의 물질 전환율을 확인하였다. 에너지수지 분석 결과, 유입물의 잠재에너지 대비 바이오가스 열량을 분석하여 에너지 전환율은 평균 78.5%을 확인하였다. 바이오가스를 생산하기 위한 외부에너지원을 포함한 바이오가스 생산효율은 평균 69.4 %이며, 미이용된 유출에너지를 적용한 바이오가스 플랜트 효율은 평균 58.9 %로 나타났다.

• Transactions on Electrical and Electronic Materials
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• 제15권3호
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• pp.144-148
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• 2014

The purpose of this research is to utilizing the Tetrax$^{(R)}$ balance measuring instrument in order to analyze the postural balance of males and females in their 30 s diagnosed with chronic lower back pain who have followed a 12-week rehabilitation exercise program. The research also examines the effects on any change in back pain level. In terms of the variables in this research, postural balance (left/right, front/back, postural balance) and pain level change (0~100 mm) were measured. Pre-/post-experimental differences were assessed using the paired-t test. In addition, to identify any gender gap, we set the preliminary scores as a covariate and ran the Analysis of Covariance. Statistical significance (a) herein was set at 0.05. As a result of this research experiment, the left/right, front/back, and overall postural balance were found to increase in both the male and female cases, but with no statistical significance or gender gap. However, both males and females showed a significant decrease in their back pain levels. These findings demonstrate the necessity of continuing clinical research based on the Tetrax$^{(R)}$ equipment for scientific evaluation of the effects of rehabilitation exercises on chronic lower back pain patients and their balancing ability.

• 디지털융복합연구
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• 제11권4호
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• pp.361-368
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• 2013

본 연구에서는 스프린터와 스케이터 패턴을 통합한 PNF 통합 패턴 운동이 만성 요통 노인 환자의 정적 균형과 동적 균형의 변화를 알아보고자 실시하였다. 본 연구는 만성 요통의 질환이 있는 노인 환자 34명을 대상으로 하였고, 34명을 무작위로 각각 PNF 통합 패턴 운동군(17명)과 스위스볼 운동군(17명)으로 나누었다. 운동전후에 정적 균형 능력 측정을 위해 GOOD BALANCE system(Metitur Oy, Palokka, Finland, 2003)을 사용하였다. 동적 균형 능력 측정을 위해 기능적 팔 뻗기 검사(functional reach test; FRT)와 일어나 걸어가기 검사(timed up and go test; TUG)를 시행하였다. 정적 균형 능력과 동적 균형 능력의 거의 대부분의 항목에서 유의한 차이를 나타내었다(p<.05). 군간 비교에서도 다수의 항목에서 스위스볼 운동군과 PNF 통합 패턴 운동군 사이에 유의한 차이를 나타내었다(p<.05). 이와 같은 연구 결과로 볼 때 PNF 통합 패턴 운동은 만성 요통 노인 환자의 균형 능력을 개선시키는데 효과적임을 알 수 있었으며, 임상에서 PNF 통합 패턴 운동을 이용할 수 있는 기초 자료를 충분히 제공하였다고 할 수 있을 것이다.

• 한국농공학회논문집
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• 제48권5호
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• pp.73-80
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• 2006

The mono-layer cover system is composed of soils only as a filling material and various plants are planted on the surface to control the water balance in the cover system. In this paper, the mono-layer cover system was considered as an alternative landfill final cover system and developed a model that could utilize industrial by-product (especially, coal ash & phosphogypsum) as additive filling materials. The mixture of granite soil, coal ash, and phosphogypsum was placed as a cover material in a box constructed with cement. Laboratory tests were carried out to investigate the environmental effect on the utilization of coal ash & phosphogypsum and to determine the mxing ratio of each materials. In the leaching test, all materials showed lower heavy metal concentration than the threshold values of regulation. The optimum mixing ratio of materials which was applied to field model test was determined to soil (4) : coal ash (1) : phosphogypsum (1) on the volume base. Field model tests were continued from February to July, 2004 in the soil box that was constructed with cement block. It was verified that coal ash and phospogypsum mixed with soil was to be safe environmentally and the water balance of mono-layer cover system was reasonable.

• 한국수산과학회지
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• 제52권1호
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• pp.74-80
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• 2019

Nonylphenol is an endocrine-disrupting chemical that is the degradation product of the nonionic surfactants nonylphenol ethoxylates. To understand the contamination and behavioral characteristics of nonylphenol, we measured the nonylphenol concentrations in surface water in the lower reaches of the Suyeong River, Korea. The results were used to estimate the material balance. The target area was divided into three regions to estimate the material balance of nonylphenol. In region 1, in flux of the dissolved nonylphenol was 282.3 g/day and the nonylphenol influx in particulate suspended solids was 1,582.8 g/day. The dissolved nonylphenol outflow discharged toward region 2 was 192.5 g/day, while the adsorption to particulate suspended solids was 89.8 g/day. Within the particulate suspended solids, the outflow to region 2 was 1,250.0 g/day, while the estimated amount settling in the sediments was 422.7 g/day. The adsorption of dissolved nonylphenol to the particulate suspended solids in regions 1 and 2 was 31.8% and 54.9%, respectively. In region 3, the desorption rate was 8.8%.

• 한국표면공학회지
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• 제35권2호
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• pp.129-137
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• 2002

The purpose of solderability assessment is to predict the effectiveness of soldering process. It is important for companies pursuing zero defects manufacturing because poor solderability is the major cause of two third of soldering failures. The most versatile solderability method is wetting balance method. However, there exist so many indices for wettability in the wetting balance test e.g. time to reach 2/3 values of maximum wetting force, tine to reach zero wetting force, maximum withdrawal force. In this study, three solderability assessment methods, which were the maximum withdrawal force, the wetting balance and the dynamic contact angle (DCA), were evaluated by comparing each other. The wetting balance technique measures the solderability by recording the forces exerted from the specimen after being dipped into the molten solder. Then the force at equilibrium state can be used to calculate a contact angle, which is known as static contact angles. The DCA measures contact angles occurred during advancing and withdrawing of the specimen and the contact angles are known as dynamic contact angles. The maximum withdrawal force uses the maximum force during withdrawal movement and then a contact angle can be calculated. In this study, the maximum withdrawal force method was found to be an objective index for measuring the solderability and the experiment results indicated good agreement between the maximum withdrawal force and the wetting balance method.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 사용종료 매립지의 안정화 에 관한 국제 세미나
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• pp.97-101
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• 1996

Municipal and sanitary landfills can pose environmental problems due to leachate, landfill gas md unstable geotechnical properties. Most governmental bodies delay the correction of landfill problems or landfill replacement until a crises stage is reached. The replacement of a landfill is often made difficult due to costly regulatory controls, public opposition to siting and the high cost of closure for the previous landfill unit. Solutions to extending landfill life and capacity Involve waste minimization by recycling, refuse compaction and waste-to-energy incineration. Incineration can reduce the volume of refuse by 50-95%. The largest installed bases of municipal waste Incinerators are located in Japan and the U.S. The volume of waste contained in a landfill can be estimated by load count tabulations, weight-and-volume measurements or a material balance analysis based on the trash profile of user categories. for an existing landfill, core samples may be collected and analyzed for use in a material balance analysis. Newly generated refuse contains approximately 50% of the heating value of coal. However, landfill properties vary significantly due to the waste profile of the contributors and biodegradation due to time and weathering. The volume of the Nanji-do landfill

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권1호
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• pp.42-50
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• 2001

The activity of immobilized cell-support particle aggregates is influenced by physical and biochemical elements, mass transfer, and physiology. Accordingly, the mathematical model discussed in this study is capable of predicting the steady state and transient concentration profiles of the cell mass and substrate, plus the effects of the substrate and product inhibition in an immobilized cell-support aggregate. The overall mathematical model is comprised of material balance equations for the cell mass, major carbon source, dissolved oxygen, and non-biomass products in a bulk suspension along with a single particle model. A smaller bead size and higher substrate concentration at the surface of the particle, resulted in a higher supply of the substrate into the aggregate and consequently a higher biocatalyst activity.