• 대한교통학회지
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• 제29권2호
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• pp.7-14
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• 2011

본선 교통류 제어 방안 중 가변속도제어 모형을 제시하고 서울 내부순환로를 중심으로 효과를 검증하였다. 차량 검지기로부터 수집된 데이터 보정 및 평활화 수행후 패턴분석을 통해 도시고속도로의 평일 상태를 4가지로 분류하고 중심 값을 산출하였다. 그리고 분석단위의 상태를 판단하기 위한 상태변수로 전이교통량, 평균밀도, 평균속도를 설정하였으며 제시된 모형과 시나리오에 근거하여 검증한 결과 안전성 및 효율성을 향상시킬 수 있었다. 또한 유입교통량에 따라 가변속도제어의 감속 정도와 유효 적용시간을 산출하였다.

• 한국토양비료학회지
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• 제48권2호
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• pp.94-99
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• 2015

The performance of chamber and bag digesters for solid state anaerobic digestion (SS-AD) of separated solid fraction of swine manure was investigated using lab-scale digester (4,460 mL total volume and 1,800 mL of effective volume) operating at $37^{\circ}C$ for 63 days. The performance of two different digester types was evaluated in terms of the kinetic constants of methane production obtained from the Gompertz and Gaussian equations. Methane production potential of chamber and bag digester was 202 and $218N{\cdot}mL$ $CH_4/g$ VS. Time to produce 95% methane production potential (T95) and calculated effective anaerobic digestion time were 55.5 days and 41.8 days for chamber digester and 52.8 days and 43.5 days for bag digester, respectively. Our results reveal that the performance was not significantly different between chamber and bag digester.

• 한국지반환경공학회 논문집
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• 제10권7호
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• pp.143-150
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• 2009

연약지반의 적정 압밀속도 및 압밀침하량 예측에 있어 유효응력, 투수계수, 압밀계수, 체적변화계수 등의 물질함수는 가장 중요한 요소로 작용한다. 본 연구에서는 수평배수 조건에서의 압밀 물질함수 산정을 위한 개량형 수평배수 압밀시험 장치를 고안하고, 이를 이용하여 고함수비 해성점토에 대한 압밀시험을 실시하였다. 시험에 이용된 시료는 상부 준설매립 지반과 하부 원지반점토로 구성된 남해안 산업단지 조성 현장에서 채취하였다. 기존의 표준압밀시험을 동시에 실시하였으며, 이 결과를 이용하여 배수조건별 간극비, 유효응력, 투수계수, 압밀계수, 체적변화계수 등을 분석하였다. 압밀 물질함수는 Stark(2005)이 제안한 소성지수 포함의 회귀분석 방정식 형태로 표현되었으며, 이를 통해 투수성에 대한 이방성 특성을 산정할 수 있었다.

• Composites Research
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• 제15권5호
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• pp.27-34
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• 2002

본 연구의 목적은 (주)한국와이바의 CF3327 평직 복합재료의 열전도도를 실험적으로 계측하고 이를 이론적인 예측과 비교하는데 있다. 열전도도 계측을 위하여 비교계측법의 원리를 이용한 실험 장치를 제작하였으며 열전도도가 잘 알려진 그라파이트를 실험함으로써 장비의 정확성을 확인하였다. 미시역학적인 방법은 섬유 및 기지의 물성, 섬유체적비, 직조 형태 등의 변수들이 복합재료의 유효물성치에 미치는 영향을 평가하는데 유용하다. 본 연구에서는 3차원 직-병렬 열저항 개념을 주기적으로 반복되는 평직의 단위구조에 적용하여 열전도도를 예측하였다. 해석 결과를 실험 결과와 비교한 결과 잘 일치함을 확인하였고 섬유체적비가 에폭시 수지 복합재료의 열전도도에 미치는 영향을 고찰하였다.

• 한국물환경학회지
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• 제20권4호
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• PNF and Movement
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• 제18권2호
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• pp.297-303
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• 2020

Purpose: The purpose of this study was to examine the effects of inhalation and exhalation exercise combined with upper extremity proprioceptive neuromuscular facilitation pattern on two spirometry values: forced volume vital (FVC) and peak expiratory flow (PEF). Methods: Thirty-two healthy adults were divided into two groups: 1) a combined group, which performed upper extremity D2 flexion pattern (shoulder flexed/abducted/external rotated, forearm supinated, wrist radial deviated, and finger extended) during exhalation and D2 extension pattern (shoulder extended/adducted/internal rotated, forearm pronated, wrist ulnar deviated, and finger flexed) during inhalation; and 2) reverse combined group, which performed the D2 flexion pattern during inhalation and the D2 extension pattern during exhalation. The inverse application of upper extremity movements during inhalation and exhalation induced selective resistance or assistance on respiration. FVC and PEF were measured at two time points, before and after four weeks. Results: In both groups, the pre-post intervention comparison showed significant increases in FVC and PEF (p < .05). In the between-groups comparison, the reverse combined group showed a significantly higher PEF than the combined group at four weeks post intervention (p < 0.05). Conclusion: The combined respiration exercise with reverse PNF upper extremity patterns using selective resistance showed an effective increase in PEF in healthy adults. Clinicians and researchers might consider using selective resistance as a widely applicable and cost-effective option for respiratory rehabilitation planning.

• 한국물환경학회지
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• 제24권1호
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• pp.107-117
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• 2008

Infiltration facilities are effective instruments to mitigate flood and can increase base runoff in urban watersheds. In order to analyze effects of infiltration trenches physical model experiments were conducted. The physical model facility consists of two soil tanks, artificial rainfall generators, tensiometers, and piezometers. The experiment was conducted by nine times and each case differed in rainfall intensity, rainfall duration and the type of ground surface. Measured quantities in the experiments are as follows: surface runoff, subsurface runoff, trench pipe runoff, groundwater level, water content, etc. The following resulted from the model experiment: The volume of subsurface runoff at trench watershed was maximum 78.3% compared with rainfall. This value is bigger than that of ordinary rate of subsurface runoff, and shows a groundwater recharge effect of trench. The time of runoff passing through the trench became earlier and the volume of runoff became larger with the increase of inflow into the trench, while trench exfiltration into ground became relatively smaller. The results of this study presented above show that infiltration trenches are effective instruments to increase base runoff during dry periods.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2006년도 추계공동학술대회
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• pp.373-383
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• 2006

Logistics is one of the most important factors to manage a stream of materials in economic environment. Establishing effective logistics system needs to consider some constraints which are fluctuation of materials volume, a long distance between makers and consumers, one way logistics and small quantity batch production. It is estimated that Unit Load System should be a powerful method to cope with those problems. It helps to realize the key issues which are Standardization and Logistics Pool System The Material Unification of Logistics System is able to participate in all kinds of industries including manufacturing, distribution and logistics. This system has some merits which are a long distance transportation cost down, product recovery, and treatment in the unbalance of demand and supply caused by unstable materials volume. Four strategies of Material Logistics Model are Packing Rationalization, Logistics Pool System, JIT System application and establishing effective infrastructure. The Material Unification Of Logistics System based on Unit Load System achieves efficiency of logistics and largely decreases moving cost.

• 전기전자학회논문지
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• 제21권3호
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• pp.288-296
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• 2017

The enhancement of photoluminescence of Au-$TiO_2$ nanoparticles by surface plasmon resonance has been studied extensively by experiment in recent years. For the purpose of optimizing the photoluminescence property of Au-$TiO_2$ nanoparticles, the manufacturing parameters related to the Au nanoparticles and $TiO_2$ nanoparticles need to be considered. In this paper, Drude model and Maier's effective volume method are used to analyze the variation of the metal nanoparticle radius, separation between metal nanoparticle and dielectric molecule, and total absorption cross-section with original radiative efficiency on the photoluminescence property of Au-$TiO_2$ nanoparticles. The results show that to obtain the optimized enhancement factor for photoluminescence process, the size of Au nanoparticle is about 13 - 20 nm, the separation between Au nanoparticle and $TiO_2$ molecule is about 5 -15 nm, the total absorption cross-section of $TiO_2$ molecules is about $1-100nm^2$ and the original radiative efficiency of $TiO_2$ molecule is weak about 0.001- 0.1. With these fabrication parameters, the photoluminescence property of Au-$TiO_2$ nanoparticles can be enhanced several thousand times compared to traditional $TiO_2$ nanoparticles.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.884-894
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• 2015

Background: Fibers in concrete resist the growth of cracks and enhance the postcracking behavior of structures. The addition of fibers into a conventional reinforced concrete can improve the structural and functional performance of safety-related concrete structures in nuclear power plants. Methods: The influence of fibers on the ultimate internal pressure capacity of a prestressed concrete containment vessel (PCCV) was investigated through a comparison of the ultimate pressure capacities between conventional and fiber-reinforced PCCVs. Steel and polyamide fibers were used. The tension behaviors of conventional concrete and fiber-reinforced concrete specimens were investigated through uniaxial tension tests and their tension-stiffening models were obtained. Results: For a PCCV reinforced with 1% volume hooked-end steel fiber, the ultimate pressure capacity increased by approximately 12% in comparison with that for a conventional PCCV. For a PCCV reinforced with 1.5% volume polyamide fiber, an increase of approximately 3% was estimated for the ultimate pressure capacity. Conclusion: The ultimate pressure capacity can be greatly improved by introducing steel and polyamide fibers in a conventional reinforced concrete. Steel fibers are more effective at enhancing the containment performance of a PCCV than polyamide fibers. The fiber reinforcementwas shown to bemore effective at a high pressure loading and a lowprestress level.