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      • 토양에서 클로르피리포스의 동력학적 거동

        유현철,신남철,우성훈,박승조 東亞大學校 附設 環境問題硏究所 2004 硏究報告 Vol.26 No.-

        We have investigated physicochemical characteristics and behavior of chlorpyrifos(CPF) in the agricultural soil, soil + dry waste food(DWF) and soil +manure. Experiments were accomplished biological degradation of samples loaded with chlorpyrifos in incubator at 27℃ during 30days in laboratory. In this study, Sample containing soil + manure has shown to be better biological degradation than sample of soil + DWF. The kinetics of chlorpyrifos oxidation catalyzed by agricultural soil, soil + DWF, and soil + manure can be described by Henri-Michaelis-Menten equation, V=(Vmax)/( Km+ C), where Vmax is the maximum velocity and Km the concentration of the substrate(C) corresponding to an initial(V) half of Vmax. The value of Vmax and km is 0.0588㎍CPF/g.soil.hr and 7.3529㎍CPF/g.soil in agricultural soil, 0.0601㎍CPF/g.soil∙hr and 4.4117㎍CPF/g.soil in the soil loaded DWF and 0.0890㎍CPF/g.soil∙hr and 4.2818㎍CPF/g.soil in the soil added manure. Therefore the order of Vmax. were Manure> DWF> Agricultural soil.

      • Cr,Cu,Fe가 첨가된 MgO 단결정의 열자극 발광 스펙트럼 분석

        田耕南,兪昇喆,杜夏榮,李春鎬 全北大學校 1994 論文集 Vol.38 No.-

        On the MgO single crysital doped artificially with Cr, Cu, Fe we observed thermally stimulated luminescence(TSL) glow curves and spectra, and analyzed them in the temperatured range from 500 to 77 k after excitation with UV or X-ray irradiation. TSL glow curves obtained from these samples show five peaks at 136.5K, 223.5 K, 390 K, 440 K, and their estimated activation energies are 1.08 eV, 0.27 eV, 0.63 eV, 1.19 eV, and 1.33 eV, respectively. When we measured TSL spectrum at the range of 200 nm to 650 nm, we also analysed the peak wavelength which obtained at 345 nm, 375 nm, and 410 nm from measurement of TSL spectrum and described their luminescence mechanisms.

      • 특수공작기계에서 쇼트피닝기의 특성 및 투사속도에 관한 연구

        노승남,이승호,서유원 서울산업대학교 산업대학원 2000 大學院論文集 Vol.7 No.-

        As developing the technology in industry, the materials with superior grade of stiffness and lightness are required, and hence the higher fatigue strength characteristics are necessary. Thus, the non-traditional machining to increasing fatigue strength is becoming influence as very important technology. Shot peening process is essential to ensure repeatability and uniformity on a part to part and lot to lot basis, while conforming to the applicable specifications. The shot material, size, shape and hardness as well as velocity and impact angle must be rigidity controlled to provide consistency in peening results. High velocity of the shot ball increases the impact energy, the shot peening intensity increase. Comparing with the are height for the velocity 42m/sec, the are height for 56m/sec and 70m/sec increase 33% and 48% respectively.

      • ZnSe 단결정에 대한 열자극 발광과 열자극 전류의 동시측정

        전경남,유승철,고석룡,신용규,김택성,이춘호 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.17 No.-

        두 종류의 ZnSe 분말을 사용하여 sublimation 방법으로 성장한 ZnSe 단결정(as grown)에 대하여 TSC와 TSL을 동시 측정하였으며, PL과 DLTS를 측정하였다. PL 측정으로 I_1, I_2와 DAP 발광을 관측하였으며 DLTS에 의한 깊은준위를 관측하였다. TSL과 TSC의 동시 측정으로부터 얻은 그로우 곡선을 점근 해법으로 분해하여 세개의 준위를 얻었으며 그들의 활성화에너지값은 0.22 eV, 0.30 eV, 0.39 eV이었다. PL spectrum과 열자극 완화과정의 동시 측정 결과로부터 0.22 eV 근방에 impurity에 의한 주게준위와 native defect에 의한 받게준위가 각각 전도대의 아래와 가전자대의 위에 존재하는 것으로 판명되었다. DLTS 측정과 동시측정 결과로부터 0.30 eV와 0.39 eV의 준위는 V_se vacancy와 관련되는 주게 준위임을 알았다. Simultaneous measurements of TSL were carried out on ZnSe single crystals grown by high pressure Bridgman technique and the PL and DLTS signals were observed. Photoluminescence spectrum at 10 K on the ZnSe crystal reveals I_1 and I_2 lines, as well as DAP emission line. DLTS spectrum on the ZnSe crystal show electron trap at 0.33 eV. Two TSC and TSL peaks were observed near 215 K and 230 K, which are identified as having originated from two donor trap levels at 0.30 eV and 0.39 eV, respectively, below the bottom of the conduction band. We also observed single TSL and TSC peaks at 150 K which were identified as having originated from a donor and acceptor trap levels at about 0.22 eV below the conduction band and over the top of the valence band, respectively.

      • KCI등재후보
      • KCI등재

        Ergonomic Analysis of Tele-operation Tasks and Remote Handling Devices for a Pyroprocessing Facility

        Seung Nam Yu,Jong Kwang Lee,Sung Hyun Kim,Byung Suk Park(번역자),Ki Ho Kim,Il Je Cho 대한인간공학회 2013 大韓人間工學會誌 Vol.32 No.1

        Objective: The aim of this study is ergonomic analysis of tele-operation tasks using modified remote handling devices dedicated to the cell of PRIDE(PyRoprocess Integrated inactive DEmonstration facility) in KAERI(Korea Atomic Energy Research Institute). Background: Tele-operation manipulators of the PRIDE are applied to perform the remote handling and management of pyroprocessing facilities. Generally, these kinds of systems are composed of master-slave system and its peripherals installed along a wall or ceiling of the cell, and the manipulators transmit the user"s own motion to grippers directly. However, a user convenience and intuitiveness while operating the manipulators have not been fully considered in research fields. Method: This study tries to analyze the ergonomic performance of remote handling manipulators in the developed cell facility. It was included that the analysis of operator"s capability for his/her own motion range of upper arm while manipulating the MSM, considerations of its manipulation margin and related tool modifications to improve the remote handling performance. Conclusion: The test results of several remote handling tasks performed in PRIDE are represented, and adequate operation strategies for the tele-operation system of hot-cell type facilities are proposed. Application: The knowledge represented in this study can be utilized to improve a tele-operation system operated in a large-scale hot-cell system.

      • SCIESCOPUSKCI등재

        Development of an articulated mine-detecting manipulator system for mobile robots

        Yu, Seung-Nam,Choi, Chang-Hwan,Lee, Seung-Yeol,Lee, Jeong-Yeob,Han, Chang-Soo 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.4

        This paper presents a servo motor selection technique for a mobile mine detection system which is operated in the field condition. As a first step, mine detection sensor should follow the earth profile while maintaining a constant distance to the earth surface. In order to acquire a reasonable manipulator trajectory and its required torque, a kind of modeling technique is devised to remove the unwanted fluctuations in the earth data. Then, Straete et al.'s normalization method is adopted and is improved to select the adequate actuator for each joint of manipulator. The improvements are as follows: First, an equivalent output power lines are plotted at the same load curve, which gives another selection criterion. Second, a temperature based criterion is proposed for the continuous limit, which estimates the steady state winding temperature of a motor, and can be used to determine a suitable motor and gear ratio. This formulation gives not only the selection of a motor and gear ratio, but also gives the estimated operating temperature. Finally, realized system is verified through the basic performance test.

      • KCI등재

        Prediction of Dispersal Directions and Ranges of Volcanic Ashes from the Possible Eruption of Mt. Baekdu

        Seung-Yeon Lee,Gil-Yong Suh,Soo-Yeon Park,Yeon-Su Kim,Jong-Hyun Nam,Seung-Hyun Yu,Ji-Hoon Park,Sang-Jik Kim,Yong-Sun Kim,Sun-Yong Park,Ja-Young Yun,Yu-Jin Jang,Se-Won Min,So-Jung Noh,Sung-Chul Kim,Kyo 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.1

        To predict the influence of volcano eruption on agriculture in South Korea we evaluated the dispersal ranges of the volcanic ashes toward the South Korea based on the possibilities of volcano eruption in Mt. Baekdu. The possibilities of volcano eruption in Mt. Baekdu have been still being intensified by the signals including magmatic unrest of the volcano and the frequency of volcanic earthquakes swarm, the horizontal displacement and vertical uplift around the Mt. Baekdu, the temperature rises of hot springs, high ratios of N₂/O₂ and ₃He/₄He in volcanic gases. The dispersal direction and ranges and the predicted amount of volcanic ash can be significantly influenced by Volcanic Explosivity Index (VEI) and the trend of seasonal wind. The prediction of volcanic ash dispersion by the model showed that the ash cloud extended to Ulleung Island and Japan within 9 hours and 24 hours by the northwestern monsoon wind in winter while the ash cloud extended to northern side by the south-east monsoon wind during June and September. However, the ash cloud may extent to Seoul and southwest coast within 9 hours and 15 hours by northern wind in winter, leading to severe ash deposits over the whole area of South Korea, although the thickness of the ash deposits generally decreases exponentially with increasing distance from a volcano. In case of VEI 7, the ash deposits of Daejeon and Gangneung are 1.31 × 10<SUP>4</SUP> g m<SUP>-2</SUP> and 1.80 × 10<SUP>5</SUP> g m<SUP>-2</SUP>, respectively. In addition, ash particles may compact close together after they fall to the ground, resulting in increase of the bulk density that can alter the soil physical and chemical properties detrimental to agricultural practices and crop growth.

      • KCI등재

        병렬 사형유로를 채택한 냉각판을 통한 고분자 전해질 연료전지의 균일 냉각에 대한 전산유체역학 해석 연구

        류승호(Seung Ho Yu),백승만(Seung Man Baek),남진현(Jin Hyun Nam),김찬중(Charn-Jung Kim) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.10

        고분자 전해질 연료전지(PEMFC)의 열관리는 성능 향상과 내구성 측면에서 중요한 문제이다. 일반적으로 냉각수 순환 유로를 가진 냉각판이 여러 개의 단전지 사이에 삽입되어 PEMFC 내부에서 발생하는 반응열을 외부로 배출한다. 본 연구에서는 개선된 병렬 사형유로(MPSFF)를 향상된 냉각성능을 가진 냉각판 유로형상으로 제안하고, 이를 전산유체역학(CFD) 해석을 통하여 평가하였다. 비교를 위하여 냉각수 유로로 일반적으로 사용되는 사형유로 및 병렬형유로의 냉각성능에 대한 계산도 수행하였다. CFD 결과는 개선된 병렬 사형유로가 냉각판 표면에서의 온도의 비균일도를 상당히 감소시키고, 따라서 PEMFC의 내구성과 성능을 향상시킬 수 있음을 보여주었다. Thermal management is important for enhancing the performance and durability of polymer electrolyte membrane fuel cells (PEMFCs) and is taken into account in the design of PEMFCs. In general, cooling pates with circulating liquid coolant (water) are inserted between several unit cells to exhaust the reaction heat from PEMFCs. In this study, computational fluid dynamics (CFD) simulations were performed to characterize the uniform cooling performance of parallel multipass serpentine flow fields (MPSFFs) that were used as coolant flow channels in PEMFCs. The cooling performances of conventional serpentine and parallel flow fields were also evaluated for the purpose of comparison. The CFD results showed that the use of parallel MPSFFs can help reduce the temperature nonuniformity, and thus, can favorably enhance the performance and durability of PEMFCs.

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