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        검색결과 1,395

        502.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Antibiotic Detection Kit (Combination I), a lateral flow immunoassay (LFIA) developed for the detection of antibiotic residues in milk, was utilized for the analysis of antibiotic residues in the muscle tissue of olive flounder. After 60-min treatment by dipping in water dosed with ampicillin (200-g/ton water), the residue depletion of ampicillin was investigated in 25 cultured olive flounder (Paralichthys olivaceus). Muscles of fish were sampled on the 1st, 2nd, 3rd, 4th and 5th day after drug treatment. The concentration of ampicillin in the muscle was determined by LFIA. The absorbance ratio of the sample to the control blank (Bs/Bo) was employed as an index to determine the muscle residues in olive flounder. To investigate the recovery rate, standard solutions were added to muscle samples to give final concentrations in the muscle of 4 and 8 ng/ml. The recovery rates of all spiked samples were > 96% of the spiked value. Ampicillin was detected in the muscle of fish treated with the drug until the 2nd day of the withdrawal period. The present study showed that the LFIA can be easily adopted to predict ampicillin residues in tissue of farmed fishes.
        3,000원
        503.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents the theoretical analysis for the flow driven by surface tension and gravity force in an inclined circular tube. The governing equation is developed to describe the displacement of a Newtonian fluid that continuously flew into a circular tube by surface tension, which represents a second-order, nonlinear, nonhomogeneous and ordinary differencial form. It was found that the theoretical predictions of the governing equation were excellent agreement with the unsteady state solutions for horizontal tube and the results of force balance equation for steady state.
        4,000원
        504.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we modeled a actual shape of a plate heat exchanger into triangular grooved channel and tried to examine flow characteristics experimentally by particle image velocimetry. Five Reynolds numbers were selected with the height of grooved channel and sectional mean velocity of inlet flow. As a result, the triangular grooved channel had a compound flow consisting of the flow in lower channel and the groove flow receiving shear stress by the channel flow. The sheared mixing layer, in the boundary between the triangular groove and the channel, affected main flow to raise turbulent in the channel.
        4,000원
        505.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the actual field application of the airless paint spraying pump driven by the hydraulic power unit under high pressure condition. The velocity and the pressure distributions are obtained using the turbulent k-ε model. The flow characteristics under design condition of spraying pump was numerically conducted by commercial fluid dynamic code(CFX ver. 13). The numerical analysis was performed by transient technique according to the variation of stroke times, which is changing from 0 to 1 seconds by interval of 0.01. Turbulence model, k-ω SST was selected to quaranty more accurate prediction of oil flow. The ICEM-CFD 13 and CFXMesher, reliable grid generation software were also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate was supplied to the paint spraying pump is 5l/min. These results are in good agreement with design results and could be applied to the design of the high viscosity paint spraying pump.
        4,000원
        506.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, the heat and flow analysis in a condenser of vehicle HVAC system was investigated numerically regarding the different shapes of the condenser tube. The velocity, pressure, and temperature distribution of the test fluid(R-134A) inside the tube were numerically calculated for the optimum design of the condenser tube for two different length with four different inlet velocities. In addition, the local pressure and temperature distributions for total tube length were calculated and the variation of pressure drop of the R-134A with flow rate were also calculated numerically. The tube at case 1 with less curved elbows was determined for the better design than case 2 in the aspect of energy-effective shape of the condenser tube.
        4,000원
        507.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Autotelic user activity and rich user experience can be the key factors causing immersion as an intrinsic motivation of steadily using smartphones. We have selected Csikszentmihalyi's Flow as a basic and theoretical framework of study on the intrinsic motivation. We have derived which user experience design factors bring about flow while using smartphones. We have collected specific key words by literature analyses, web sites survey and in-depth interviews and have summarized. As a results, the user experience design factor is categorized into usability, personalization, physical satisfaction, interactivity, aesthetic satisfaction, usefulness. The 6 design measures are different from general categories of previous media and interface design researches, but they are based on emperical data and realistic factors which reflect design characteristics of smart phones.
        4,000원
        508.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Material flow control (MFC) is a kind of operational policy to control of the movement of raw materials, components, and products through the manufacturing lines. It is very important because it varies throughput, line cycle time, and work-in-process (WIP) under the same manufacturing environments. MFC can be largely categorized into three types such as Push, Pull, and Hybrid. In this paper, we set various manufacturing environments to compare five existing MFC mechanisms: Push, Pull, and Hybrid (CONWIP, Gated MaxWIP, Critical WIP Loops, etc). Three manufacturing environments, manufacturing policies (make to stock and make to order), demand (low, medium, high), and line balancing (balanced, unbalanced, and highly unbalanced) are considered. The MFCs are compared in the point of the five functional efficiencies and the proposed compounded efficiency. The simulation results shows that the Push is superior in the functional efficiency and GMWIP is superior in the compounded efficiency.
        4,000원
        509.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of the cavity behind Rectangle Bluff Body in turbulent single-phase flow was studied using Particle Image velocimetry (PIV). The results for the time-averaged velocity showed a recirculation flow behind the bluff body. The horizontal location behind the bluff body where the time-averaged vertical and horizontal velocity components were zero was found at approximately 1.2H and the end of the re- circulation region was shifted upstream by effect of the cavity.
        4,000원
        510.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigated the blood flow at microvascular network. The role of the blood viscosity and the yield stress of blood on the flow at the microvascular network was examined to find the condition of hemostasis. When the yield stress was less than 0.005Pa, there was no stagnant region in the capillary network used in the study. However, when the yield stress increased to 0.05Pa, stagnant areas began to appear, which grew and expanded rapidly with further increase in the yield stress. From the blood viscosity profile of a patient, one can estimate the yield stress of blood, from which the risk of hemostasis can be determined.
        4,000원
        511.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The SMC(Sheet molding compound) process is widely used in the automotive industry to produce parts that are large, thin, lightweight, strong and stiff. Compression molded parts are formed by squeezing a glass fiber reinforced UP(Unsaturated Polyester) sheet, known as sheet mold compound(SMC), between two heated cavity surfaces. This paper has performed flow analysis to predict optimization process of low density SMC. After five types of design variables and six types of response variables were defined, DOE(Design of Experiment) and RSM (Response Surface Method) were applied in order to measure sensitivity of design variables and realize optimization through regression model. After design optimization, the total warpage of the SMC is reduced by about 12% compared to the initial design of SMC and cure time, cure temperature, clamping force and flow pressure are decreased by 0.6∼27% in comparison with the initial design. By doing this, the production costs could be diminished.
        4,000원
        512.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        보일러 배기가스를 이용해 온실 내부의 CO2 농도를 높여 식물의 생장을 촉진하는 CO2 시비 시스템의 공급 최적화를 위한 연구를 진행하였다. 다기관의 유로를 사용하는 시비 시스템의 기하학적 변수에 따른 유량균일성 파악을 위해 전산유체역학 기법을 사용하였다. 먼저 PVC 형상을 수정하여, 처음 설비에서 출구유량이 적어 튜브 뒤쪽까지 CO2가 나오지 못했던 문제점을 해결하고 개선된 형상을 결정했다. 그 다음 실험값과 동일하게 맞추기 위하여 실험값과 해석값의 출구 속도를 비교하여 입구 압력을 결정하였다. 이때 여섯 개의 출구에서 나타나는 유량 비균일성은 출구에 Gasket을 부착하여 출구 면적 변화를 통해 유량을 조절할 수 있다고 보았다. 여섯 개의 출구 직경을 각각 변화시킨 3개의 Case 결과가 출구 면적을 모두 동일하게 두었을 때보다 편차가 최대 ±18%까지 감소되었다. 비닐 튜브 역시 뒤쪽까지 CO2가 전달되지 못하는 문제점을 해결하기 위하여 출구의 직경을 변화시켜가며 비교하였다. 각각의 출구 직경은 동일하게 하고 입구 면적 대비 출구 면적이 153.4%(D = 10mm), 97.8% (D = 8mm), 54.9%(D = 6mm)이 되도록 3개의 Case로 나누어 유량 균일성 향상 효과를 알아보았다. 그 결과 출구직경이 10mm일 때보다 6mm일 때, 유량 편차가 ±13% 정도 감소되었다. 따라서 출구 면적이 작아질수록 유량 균일성이 향상됨을 파악하였다. 앞서 결정된 최적 PVC 형상과, 비닐 튜브 조건을 조합하여 전체 형상을 해석한 경우 역시 모든 hole에서의 유량이 0.1g/s 이내의 차이를 보이며 높은 균일성을 나타냈다. 이와 같은 방법으로, 다기관의 유로를 이용하여 CO2를 분배시키는 다른 형태의 시비 시스템에서 역시 PVC 배관에서의 압력강하를 최소화시킨 뒤, PVC와 비닐 튜브의 출구 직경을 변화시키는 순서로 각 출구로의 유량을 균일하게 조정할 수 있을 것으로 판단된다.
        4,000원
        514.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study aims to suggest a proper left-turn treatment method for the bicycle traffic flow at four-legged intersections. METHODS: Four types of crossing methods are proposed and analyzed : (1) indirect left turn, (2) direct left turn, (3) direct left turn on a Bike Box, and (4) direct left turn on bike left turn lane. The VISSIM simulation tests were conducted based on forty-eight operation scenarios prepared by varying vehicle and bicycle traffic volumes. RESULTS : The results from the four-legged signalized intersections suggest that (1) the indirect left turn is appropriate when vehicle demand is high, (2) the direct left turn is efficient on most traffic situation but the safety is a concern, (3) the direct left turn on a Bike Box is appropriate when bicycle demand is high while vehicle demand is not, and (4) the direct left turn on a bike left turn lane is appropriate when both vehicle and bicycle demand are low. CONCLUSIONS : The direct left turn of bicycle provides more efficiency than the indirect left turn at the four-legged intersections but to apply the methods and to study more, advanced evaluation methods, related law, and insurance programs are needed.
        4,500원
        515.
        2013.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Silicon nanoparticle is a promising material for electronic devices, photovoltaics, and biological applications. Here, we synthesize silicon nanoparticles via CO2 laser pyrolysis and study the hydrogen flow effects on the characteristics of silicon nanoparticles using high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and UV-Vis-NIR spectrophotometry. In CO2 laser pyrolysis, used to synthesize the silicon nanoparticles, the wavelength of the CO2 laser matches the absorption cross section of silane. Silane absorbs the CO2 laser energy at a wavelength of 10.6μm. Therefore, the laser excites silane, dissociating it to Si radical. Finally, nucleation and growth of the Si radicals generates various silicon nanoparticle. In addition, researchers can introduce hydrogen gas into silane to control the characteristics of silicon nanoparticles. Changing the hydrogen flow rate affects the nanoparticle size and crystallinity of silicon nanoparticles. Specifically, a high hydrogen flow rate produces small silicon nanoparticles and induces low crystallinity. We attribute these characteristics to the low density of the Si precursor, high hydrogen passivation probability on the surface of the silicon nanoparticles, and low reaction temperature during the synthesis.
        4,000원
        516.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 중학생 사회과부도의 유선도의 색채 디자인을 사용자 중심으로 개선하는데 목적이 있다. 이를 위해 먼저 사회과부도 주제도의 색채 디자인에 대한 학생들의 선호도를 조사하였다. 그리고 지도의 색채 개선을 위해서 중학교 미술 교과서에 수록된 미술 작품에서 추출한 색채 팔레트를 이용하여 유선도를 제작하였다. 또한 지도 색채 이미지에 대한 감성 조사를 위하여 지도의 기본 속성과 색상에 대한 인식을 측정할 수 있는 20쌍의 단어를 사용한 의미차별법을 적용하여 설문 조사를 실시하였다. 결론적으로 학생들이 공통적으로 좋아하는 유선도는 흥미롭고 강렬한 인상을 주는 색상을 사용한 지도였다. 지도의 색상은 학생들의 지리 학습 흥미를 자극하므로, 사용자 중심의 지도 색채 디자인에 대한 연구는 지속적으로 이루어져야 한다.
        4,200원
        517.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical analysis has been carried out to investigate thermal characteristics for hydraulic system. Overall performance of hydraulic system is largely influenced by oil flow field with heat transfer. Especially thermal characteristics for operating conditions with high oil temperature caused by heavy load and continuous operation are dominant. Oil temperature variation with time in the system is predicted for various flow conditions. Local fluid flow fields at the pipelines, valves, and oil pump in the hydraulic system are considered with thermodynamic and transport properties such as density and viscosity. These results in the study can be applied to the optimal design of hydraulic system.
        4,000원
        518.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The temperature distribution of a generic battery module was analyzed for different flow rates of cooling fluid. For the given battery module design, the temperature of battery cell near the inlet is higher than that of battery cell near the outlet. Because the inlet is located at the higher elevation than the top of battery electrodes, most of the incoming cooling fluid flows directly towards the battery housing wall above the outlet. For the inlet velocities of 1, 3, 5 m/s, the maximum temperature differences are 28, 19, 15 degrees Celcius respectively.
        4,000원
        519.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is about comparison of thermal and flow characteristics on the wind & radiant heat shield with STS mesh type screen for offshore plant. Numerical analysis was conducted to find transmission coefficient in the mesh and then analyse the flow characteristics about wind & radiant heat shield. The experiment method of solar radiation has been used as thermal radiation source to get the performance of radiant heat shield measurement. The sensor radiation device has been used to measure the reduction of solar radiation with various size of cells and at a distance of 0.5m and 1m from the cold face of the wind & radiant heat shield. The present study show reduction in radiation heat flux as various distance from the cold face of the radiant heat shield. Experimental results are presented for different type of mesh and distance of measurement.
        4,000원
        520.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flow control of flow field is essential to design efficient elements relating to fluid machineries. In this study, the flow characteristics of rectangular prism with throughflow at different aspect ratio was investigated to flow control. A particle image velocimetry technique was employed to obtain detailed measurements at throughflow-velocity-based Reynolds numbers. As a results, the throughflow disturbs the development of vertical velocity component and decreased the vortex size.
        4,000원