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        검색결과 314

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Air blower has been widely used in many industrial fields such as wind tunnel and large ventilation systems. Its performance is affected by operating conditions and system geometry of inpeller and duct, and these design parameter optimization is essential for the effective development. CFD analysis is carried out to investigate the air flow field characteristics with outlet total pressure in a blower system. Intake air into the impeller blade through the inlet is compressed, and then gradually discharged from the outlet with ascending total pressure, and predicted results are compared with test data. Especially this overall pressure difference in the blower system severely depends on the flow rate. These results are expected to be used as applicable design data for blower performance improvement.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Application areas of floating marine structure systems have been increased with the development of power generation systems using renewable energy. Hence it is necessary to analyze the behavior of these floating systems for efficient design and operation. In this study, a computational analysis was performed to predict the characteristics of mooring lines load variation connected to a floating marine structure with waves. Pressure on the floating body and mooring lines load were analyzed with wave direction and height. The floating body stability severely decreased for 90° of the wave incident direction, and maximum load of the mooring lines increased with the height. These results are expected to be applicable for optimal design of the marine floating system.
        4,000원
        7.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the protein content and functional changes in soybeans cultured with Phellinus linteus HN00K9 were analyzed. P. linteus HN00K9 was cultured on soybeans. The crude protein content in soybeans cultured with HN00K9 (PMS) was 41.99%, which was higher than that in soybeans not cultured with the mushroom (UCS). The total free amino acid content in PMS increased to 39,963 mg/100 g, which was higher than that in UCS (36,817 mg/100 g). In particular, in PMS, glutamic acid accounted for 18.5% of the total amino acids at 7,413 mg/100 g. The total polyphenol content in PMS was 2.66 mg GAE/g, which was more than 45% higher than the amount in UCS (1.45 mg GAE/g). Additionally, PMS showed a DPPH radical scavenging activity of 33.3%, which was 3 times higher than that exhibited by UCS (11.5%), reflecting its high antioxidant content. Therefore, the PMS in this study has potential for use as a functional food material.
        4,000원
        8.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical analysis has been carried out to predict the thermal characteristics for a LED lens in mold core system. These thermal characteristics inside the lens are largely affected by geometry, material, and initial conditions of the mold core and lens system. Local temperature and heat flux variation inside the lens are compared for several initial temperatures. Maximum temperature inside the lens was decreased rapidly from the beginning of cooling process up to about 10 seconds. There was also large variation of the heat flux at the upper and lower surfaces of the lens with initial temperature distribution. And the heat flux from the thin lower surface of the lens was relatively higher than the opposite-side thick region. In addition, overall heat transfer rate from the lens through the mold core has similar transient distribution from the beginning. These results can be applied as basic heat transfer data for the LED lens design and manufacturing process in the mold core system.
        4,000원
        10.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper analyzed the price stabilization before and after the fisheries outlook project for seaweed, flatfish, and abalone. First, the stabilization effect was analyzed through the price variation coefficient before and after the observation project. In terms of the variation coefficient, there was no effect that the price was stabilized through the seaweed outlook project. However, it can be seen that flatfish and abalone have a price-stabilizing effect. Second, as a result of analyzing the price stabilization effect through the improved ARMA-T-GARCH model, it was confirmed that seaweed was not statistically significant while flatfish and abalone had a price stabilization effect by statistically significantly reducing volatility of real prices after the introduction of the fisheries outlook project. Third, as a result of analyzing the factors affecting price stability, it was found that the price of seaweed was stabilized after the WTO, but the Japanese earthquake expanded the price volatility. In the case of flatfish, it was analyzed that the price stabilized after the WTO and the Great Japanese Earthquake. Finally, the price of abalone has stabilized since the WTO and the Great Japanese Earthquake.
        4,300원
        12.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Structural characteristics have been analyzed for gear system in a commercial iron bending machine which is widely used at many building construction sites. This complicated gear system in the bending machine is fundamental power transfer unit from electrical motors, and it is composed of various configuration structure including various spur and helical gear assembly. Main structural characteristics of the gear system such as stress and deformation distributions are predicted with numerical simulation of FEM method for various operating conditions of torque and rotation speed. Results show that there is large deformation in lower region of driving gear, and high stress near those contact area which is greatly affected by motor torque. These results can be applied for the design improvement of efficient gear system in the iron bar bending machine.
        4,000원
        13.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Experimental analysis has been carried out on double glazed glass of a commercial vehicle to analyze thermal characteristics for various air flow conditions. This double glazed glass has an important effect on the blocking performance of heat transfer with the vehicle's moving speed and ambient thermodynamic conditions. Calculated thermal resistances and heat transmission coefficient through the glass were compared with measured air indoor and outdoor temperatures including the glass surfaces using an experimental apparatus. The thermal resistance through the glass was increased with the indoor air temperature while overall heat transmission coefficient was decreased due to the convective heat transfer effect. As indoor air became warmer, the effect of air flow velocity on the heat transmission coefficient was reduced significantly. It is expected that these results can be used as applicable design data for the development of the double glazed glass system for many commercial vehicles.
        4,000원
        14.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 남자 테니스 선수의 생맥산 섭취가 혈중 지질 및 동맥경화 지수에 미치 는 영향을 조사하는 것이었다. 남자 대학 테니스 선수 17 명을 4 주간의 고강도 테니스 하계훈련 중 생 맥산 섭취 여부에 따라 생맥산 섭취군(n=9)과 위약 대조군(n=8)으로 나누었다. 테니스 하계훈련은 4 주 간 주 5 회 실시하였으며, 운동강도는 예비심박수의 70~90%로 실시하였다. 생맥산은 아침 식사 전, 운 동 중, 운동 중, 운동 후 1 회 110ml, 저녁 식사 후 1 일 총 7 회 770ml 를 섭취하였다. 모든 데이터에 대해 평균 및 표준 편차를 사용하였으며, 시기간 및 생맥산 섭취그룹의 효과를 확인하기 위하여 반복 측정분산분석법을 사용하였고, 생맥산 섭취 후 혈중 지질의 차이에 대한 관련성을 알아보기 위하여 Pearson 의 상관분석을 실시하였다. 본 연구결과, 생맥산 섭취군은 혈중 지질(중성지방, 총콜레스테롤, 고밀도지단백콜레스테롤, 저밀도지단백 콜레스테롤)과 동맥경화지수가 유의하게 개선되었으며, ⲆTG, Ⲇ LDL 및 ⲆTC 간에는 유의한 상관관계가 나타났다. 결론적으로 남자 대학 테니스 선수의 고강도 트레이 닝 시 생맥산 섭취는 혈중 지질 및 동맥경화 지수에 긍정적인 영향을 미칠 수 있어 운동 보조제로서 효 과적인 스포츠 음료가 될 수 있음을 시사한다.
        4,300원
        15.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical analysis has been carried out to investigate the characteristics of seawater flow fields and turbine output in a compact double current tidal power generation system for various level differences. There are growing concerns for the development of efficient tidal power generation which is stable and less affected by environmental circumstances as ocean energy. Especially the flow field characteristics in the compact tidal power generation system have a large influence on the system power generation performance. Flow velocity, pressure, and streamline distributions are compared including vertical type turbine out, and it can be predicted that seawater is accelerated by vortex flow in front of the turbine and there is severe turbine output variation due to the water level difference with pressure difference. These results can be applied as basic data for the effective development of compact tidal power generation system.
        4,000원
        17.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical analysis has been carried out to investigate the flow field characteristics for exhaust gas in automobile engine DPF system. The DPF system performance is largely affected by exhaust gas flow while it passes through the complicated geometry of DOC/DPF system, fan shape structure, and perforated can with air for fuel combustion. Hence the characteristics of fluid velocity, pressure, and streamline are analyzed with velocity uniformity in front of DOC and swirl flow near the fan. It can be seen that the velocity uniformity increases with the gas flow rate including flow acceleration near the lower area of the fan. The air flow also influences the gas flow distribution close to the impeller and fan structure with complicated swirl flow. These results are expected to be applicable as fundamental design data for automobile engine exhaust system.
        4,000원
        18.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Building Information Modeling(BIM)기술을 유지관리 단계에서 활용하기 위해서는 상당량의 유지관리 데이터와 BIM기반 정보모델 객체들이 연계되어 운용되어야 한다. 본 연구에서는 교량 점검데이터를 표현하기 위해 확장된 IFC기반의 BIM모델과 온톨로지를 연계하여 정보를 관리하는 방법을 제시하였다. 이를 위해 현재의 IFC버전은 교량 객체를 제대로 표현할 수 없기 때문에 교량을 위한 IFC엔티티를 확장하였으며, 확장된 IFC기반의 정보모델을 생성하는 방법을 제시하였다. 또한, 교량 점검데이터에 대한 기본 개념을 추출하고, 교량 점검데이터를 위한 온톨로지(Ontology)를 생성하였다. 추출된 기본 개념들은 제시된 온톨로지에서 시멘틱 웹의 트리 플(Triple) 방식으로 관계를 형성되었다. 마지막으로, 생성된 IFC기반의 BIM모델은 제시된 온톨로지와의 통합을 위하여 시멘틱 데이터 형식으로 변환되었다. 확장된 IFC기반 BIM모델은 제시된 교량 점검데이터 관리를 위한 온톨로지와 통합되었고, 실제 교량 점검데 이터를 기반으로 테스트모델을 생성하였다. SPARQL query를 통해 목적에 맞는 교량 점검데이터가 추출됨을 확인하여 실효성을 검 증하였다.
        4,000원
        19.
        2020.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        미국을 비롯한 선진국과 한국의 노동시장에서 학력별 노동 간 임금격차가 심화되는 현상이 나타나고 있다. 본 논문은 한국 제조업 노동시장에서 발생하고 있는 학력별 임금격차를 바탕으로 인적자본론에 근 거하여 저학력노동시장과 고학력노동시장으로 분절하고 학력별 노동수요가 어떤 요인에 영향을 받는가 를 실증분석하였다. 먼저 저학력노동과 고학력노동으로 나누어 제조업의 학력별 임금격차를 설명하였다. 분석방법으로 저 학력노동, 고학력노동과 물적자본을 생산요소로 하고 외생변수로 중립적 기술진보와 세계화를 포함한 다 요소 Cobb-Douglas 생산함수를 설정하였다. 이것을 바탕으로 비용함수를 구하고 학력별 노동수요함수를 유도하여 통계자료를 사용하여 실증분석하였다. 추정결과는 첫째 저학력노동(고졸이하)과 고학력노동(대졸 이상) 간에는 보완적 관계가, 물적자본과 고학력노동(대졸이상) 간에는 대체적인 관계가 성립하였다. 둘째 제조업 생산량은 저학력노동 수요에 양 (+)의 방향으로 영향을 미치지만 고학력노동 수요에는 통계적으로 유의미한 영향은 미치지 않았다. 셋째 세계화는 고학력노동 수요를 증가시키고 저학력노동 수요를 감소하는 방향으로 영향을 미쳤다. 넷째, 중립적 기술진보는 고학력수요를 증가하는 방향으로 영향을 미치지만 저학력노동 수요에 거의 미치지 못했다. 이런 결론을 바탕으로 정책적 제안을 정리하면 다음과 같다. 첫째 경기침체 때 생산량이 줄어들면 이에 따라 저학력노동 수요가 감소하고 실업이 발생한다. 이런 상황에 대응하여 저학력노동 고용촉진정책이 필요하다. 둘째, 투자가 감소하면 자본수요가 줄어들어 자본가격이 하락한다. 고학력노동의 상대가격이 상승하여 고학력노동 수요가 감소한다. 이에 따라 보완관계인 저학력노동 수요도 감소하게 되므로 투자촉진정책이 필요하다. 셋째 세계화가 진전될수록 저학력노동의 수요가 감소하므로 저학력노동 고용증 진정책이 필요하다.
        5,400원
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