• 제목/요약/키워드: Co-working

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Preparation of Co-Cr Thin Films by Facing Targets Sputtering (대향타겟스퍼터링에 의한 Co-Cr 박막의 제작)

  • ;;;;;S. Nakagawa;M.Naoe
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.5
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    • pp.418-422
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    • 1998
  • The Co-Cr films are one of the most suitable candidates for perpendicular magnetic recording media. The facing targets sputtering(FTS) system has a advantage of preparing films over a wide range of working gas pressure on plasma-free substrate. In this study, we investigated the possibility of employing FTS system for depositing Co-Cr films. The Co-Cr thin films were deposited with various sputter gas pressure($P_Ar$, 0.1~10mTorr) by using FTS apparatus at temperature of $40^{\circ}C and 220^{\circ}C$, respectively. Crystallographic and magnetic characteristics were evaluated by x-ray diffractometry (XRD) and vibrating sample magnetometer(VSM), respectively. Under argon gas pressure at 0.1mTorr, films with morphologically dense microstructure, good c-axis orientation and higher coercivity were obtained. It has been confirmed that the FTS system is very useful for preparing Co-Cr thin film recording media.

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Development of Electro-Biosensor for the Residual Pesticides using Organic Carbon and Cobalt Phthalocyanine (Cobalt Phthalocyanine 탄소유기 전극을 이용한 농약 잔류량 측정 센서개발)

  • Yu, Young-Hun;Cho, Hyung-Jun;Park, Won-Pyo;Hyun, Hae-Nam
    • Korean Journal of Environmental Agriculture
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    • v.29 no.1
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    • pp.72-76
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    • 2010
  • We have developed the bio-electrode measuring the variance of the amount of acetylcholine affected by residual pesticide. The working electrode of the biosensor was made by combination of cobalt phthalocyanine and carbon organic compounds. The biosensors were constructed by screen-printing method. The principle of working electrode is similar to thiocholine sensor. We have fabricated the biosensor using standard screen printing method. Generally, the biosensor made by printing method formed thick film biosensor. When the electrodes were made by electrochemical cells, the generation of current by the addition of enzyme substrate was inhibited by standard solutions of organo-phosphate pesticides. The detection limit of sensor is about 0.5 $\mu{g}/L$ for carbofuran. We could improve the responsibility of the sensor by controlling the cobalt phthalocyanine and thiocholine concentration ratio. Also we have tested the EPN and Chlorpyrifos pesticides and found that the biosensor is applicable to fast determination of residual pesticides.

Numerical Study on Heat Transfer Performance of PCHE With Supercritical CO2 as Working Fluid (초임계 이산화탄소를 작동유체로 하는 인쇄기판형 열교환기의 형상변수에 따른 전열성능 수치모사)

  • Jeon, Sang Woo;Ngo, Ich-long;Byon, Chan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.11
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    • pp.737-744
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    • 2016
  • The printed circuit heat exchanger (PCHE) is regarded as a promising candidate for advanced heat exchangers for the next-generation supercritical $CO_2$ power generation owing to its high compactness and rigid structure. In this study, an innovative type of PCHE, in which the channel sizes for the heat source fluid and heat sink fluid are different, is considered for analysis. The thermal performance of the PCHE, with supercritical $CO_2$ as the working fluid, is numerically analyzed. The results have shown that the thermal performance of the PCHE decreases monotonically when the channel size of either the heat source channel or the heat sink channel, because of the decreased flow velocity. On the other hand, the thermal performance of the PCHE is found to be almost independent of the spacing between the channels. In addition, it was found that the channel cross sectional shape has little effect on the thermal performance when the hydraulic diameter of the channel remains constant.

Development of a Car Door Checker for Reducing Noise in Opening (승용차 도어의 개폐 이음 저감을 위한 도어체커 개발)

  • An, Byeongju;Son, Sungmin;Yun, Jaedeuk;Jung, Yoongho;Kim, Hyongdon;Shin, Jongil;Seo, Seungwoo;Jang, Kookjin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.4
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    • pp.396-401
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    • 2015
  • A door checker holds a car door at several opening angles and limits the maximum door opening, so that the door does not bump against to passengers. Recently, the performance of door checker becomes more important as the feeling of door opening and closing effects on the quality of a car. However, some of door checkers make squealing noise when they are used for ages, which causes consumer's complaints as well as decreasing commercial value of the product. In this study, after various experiments for the noise, we concluded that the major reasons of the noise are acceleration of wearing and loss of lubricant due to impurities in working parts. Therefore, we developed a new mechanism of door checker which can resolve the major reasons of the noise. The developed mechanism is effective to prevent inflow of impurities and loss of lubricant by locating working parts in the case. We also proved that the developed mechanism does not make any noise after the test of 50,000 times of operations.

Developing Competency Model and Analyzing Competency Needs for Construction Manager in D Co., Ltd. (건설사업관리자 역량 모형 개발 및 역량 요구 분석: D사(社) 사례를 중심으로)

  • Kim, Dae-Young
    • Journal of vocational education research
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    • v.33 no.3
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    • pp.37-56
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    • 2014
  • The purpose of this study was to develop a competency model and analyze the competency needs for construction manager in D Co., Ltd.. The delphi method of 25 excellent construction managers working in D Co., Ltd. was used to develop a competency model. The results showed that there would be a construction manager competency model which consisted of 3 competency clusters, 11 competencies, and 60 key actions. Then the survey of 114 construction managers working in D Co., Ltd. was conducted to examine concurrent construct validity of the competency model for construction manager and to analyze construction managers' competency needs by using the Borich's formula and the Locus for Focus Model(LfFM). The results showed that construction managers perceived 'communication', 'risk management', 'goal orientation', 'customer orientation', and 'project management' as top five priorities of competencies for construction managers. Based upon the above results, some implications were suggested for developing construction managers' competencies and improving their performance.

Cooling Performance of Several $CO_2/propane$ Mixtures in an Air-Conditioning System (이산화탄소/프로판 혼합냉매의 냉방성능 특성)

  • Kim, Ju-Hyok;Kim, Min-Soo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.1
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    • pp.47-54
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    • 2006
  • [ $CO_2$ ] and propane mixtures were chosen as promising alternative refrigerants and their performance potentials were evaluated experimentally in an air-conditioning system. Pure $CO_2$ and 85/15, 75/25 and 60/40 binary blends by the charged mass percentage of $CO_2/propane$ were selected as working fluids. The effect of the inlet temperature of the secondary fluids and degree of superheat on the cooling performance was tested and discussed. The charging amounts of refrigerants were adjusted to make the system show the maximum COP. Comparisons among different refrigerants were carried out on the same compressor speed basis for a given operating condition. In addition, the temperature gliding effect of zeotropic mixtures on the system performance were analyzed based on the drop-in test results.

Development of Prefabricated Joint for 66kV Cross Linked Polyethylene Cable. (66kV XLPE Cable용 조립형 접속함의 개발)

  • Oh, E.J.;Kim, K.Y.;Lee, J.Y.;Park, J.K.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2123-2125
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    • 1999
  • In recent the XLPE cable has been applied more widely because of its advantages, such as the low-cost and simple installation. For a prefabricated joint, its working time is short, its jointing procedures aγe simple, and its quality control is easy. Electrical performance targets of our developed 66kV cable accessories has been approved through the type test in accordance with IEC publication 840. This paper describes the developmental effort in terms of the design, structure and results of performance verification tests for 66kV XLPE cable system.

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Development of Optimization System in Shell Landing (Shell Landing 최적화 시스템 개발)

  • Lim, Hyung-Kyun;Kim, Jae-Chul;Lee, Ji-Hyun;Shin, Jun-Sik
    • Special Issue of the Society of Naval Architects of Korea
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    • 2011.09a
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    • pp.90-94
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    • 2011
  • Longitudinal shell member that arranged block unit on 3D-curved surface is performed manual working by designer considering spacing of division characteristic, location and twisting at geometrical 3-dimensional form. Shell expansion drawing that drawn by initial design and shell landing work performed by hull production design have overlap of design work in terms of arrangement of shell longitudinal member. In this study, eliminate design overlap on shell member arrangement that is one of ship longitudinal member. Develop shell member optimization and auto arrangement system.

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Classifier System and Co-evolutionary Hybrid Approach to Restoration Service of Electric Power Distribution Networks

  • Filipiak, Sylwester
    • Journal of Electrical Engineering and Technology
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    • v.7 no.3
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    • pp.288-296
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    • 2012
  • The method proposed by the author is intended for assistance in decision-making (concerning changes of connections) by operators of complex distribution systems during states of malfunction (particularly in the events of malfunctions, for which the consequences encompass extended parts of the network), through designation of connection action scenarios (creating substitute configurations). It is the use by the classifying system working with the co-evolution algorithm that enables the effective creation of substitute scenarios for the Medium Voltage electric power distribution network. The author also completed works concerning the possibility of using cooperation of the evolutionary algorithm and the co-evolutionary algorithm with local search algorithms. The method drawn up may be used in current systems managing the work of distribution networks to assist network operators in taking decisions concerning connection actions in supervised electric power systems.

Manufacturing LNA Board for GPS Antenna and Proposal of Verification Method

  • Choi, Dong-Hun;Kim, Mi-Suk;Kim, Jong Seong;Son, Seok Bo
    • Journal of Positioning, Navigation, and Timing
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    • v.7 no.2
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    • pp.105-112
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    • 2018
  • This paper manufactured an active GPS antenna for ground vehicles and presented a method to verify the performances of the antenna and component technology of the low noise amplifier (LNA) board manufacturing. The manufactured GPS antenna is an active antenna where microstrip patch and LNA board were combined. The main performances were standing wave ratio, antenna gain, and axial ratio, and all satisfied the target specifications. The proposed component technology can be utilized as a basis data in which the performance of LNA board can be compensated in the mass production process inspection, and employed as a method to verify whether antennas are properly working in environmental tests.