• Title/Summary/Keyword: Efficiency characteristic

Search Result 1,974, Processing Time 0.03 seconds

Analysis of a Cylindrical Pin Fin with Variable Diameter (직경이 변하는 원통형 Pin 핀의 해석)

  • Kang, Hyung-Suk;Kim, Jong-Ug
    • Journal of Industrial Technology
    • /
    • v.27 no.B
    • /
    • pp.71-75
    • /
    • 2007
  • A cylindrical pin fin with variable diameter is analyzed by using the one dimensional analytical method. Heat loss and fin efficiency are presented as a function of the fin diameter, length and convection characteristic numbers ratio. The relationship between the fin diameter and convection characteristic number over the fin for the same amount of heat loss is shown. One of the results indicates the fin efficiency increases as the fin diameter increases while that decreases as the fin length increases.

  • PDF

chalcogenide thin films of diffraction efficiency characteristic according to the wavelength (칼코게나이드 박막에서의 파장에 따른 회절효율 특성)

  • Lee, Ki-Nam;Yeo, Chul-Ho;Sin, Hyung;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2003.11a
    • /
    • pp.456-459
    • /
    • 2003
  • In this thesis, We observed the characteristic of the diffraction efficiency according to the wave length of the chalcogenide thin films. The used an $Ag(200{\AA})/As_{40}Ge_{10}Se_{15}S_{35}$ thin film. We made grating formation by each wave length 325nm, 442nm, 632.8nm. After measure diffraction efficiency of the time. We expressed the maxium saturation value at fast time as were the short wavelength and stable characteristic. On the other hand we appeard to the by a maxium diffraction efficiency the 1.7% in 325nm, 0.8% in 442nm, 0.27% in 632.8nm. The maximum diffraction efficiency expressed high value as were the long wavelength.

  • PDF

A Study on Organizational and Information System Characteristic Influencing Information Systems Planning's Performance (정보시스템계획 성과에 영향을 미치는 조직특성 및 정보시스템특성에 관한 연구)

  • Jung, Lee-Sang
    • Asia pacific journal of information systems
    • /
    • v.10 no.2
    • /
    • pp.177-196
    • /
    • 2000
  • Information Systems Planning(ISP) has gained considerable interest among researchers and practioners in recent years because of the impact of information systems on organization performance. This study aims at analyzing organizational characteristic factors, information system characteristic factors influencing ISP's performance. The organizational characteristic variables are considered organizational strategy, organizational culture, and managerial leadership. And the IS characteristic variables are considered IS resource and IS strategic role. The ISP's performance variables are measured BP-ISP integration effectiveness and ISP efficiency. For data on the 493 sampled company, a mail survey using a questionnaire was conducted in this study. The following results were obtained. First, there was significant relationship between organizational characteristics and ISP's performance. Specially, organizational strategy and organizational culture affect the both of BP-ISP integration effectiveness and ISP efficiency. Second, there was significant relationship between Information Systems characteristics and ISP's performance. Specially, IS resource and IS strategic role affect ISP efficiency.

  • PDF

Examination of Efficiency Based on Air Gap and Characteristic Impedance Variations for Magnetic Resonance Coupling Wireless Energy Transfer

  • Agcal, Ali;Bekiroglu, Nur;Ozcira, Selin
    • Journal of Magnetics
    • /
    • v.20 no.1
    • /
    • pp.57-61
    • /
    • 2015
  • In this paper wireless power transmission system based on magnetic resonance coupling circuit was carried out. With the research objectives based on the mutual coupling model, mathematical expressions of optimal coupling coefficients are examined. Equivalent circuit parameters are calculated by Maxwell software, and the equivalent circuit was solved by Matlab software. The power transfer efficiency of the system was derived by using the electrical parameters of the equivalent circuit. System efficiency was analyzed depending on the different air gap values for various characteristic impedances. Hence, magnetic resonance coupling involves creating a resonance and transferring the power without radiating electromagnetic waves. As the air gap between the coils increased the coupling between the coils were weakened. The impedance of circuit varied as the air gap changed, affecting the power transfer efficiency.

An experimental study for the prediction of combustion performance of the Unlike Impinging Quadlet Injector (충돌형 Quadlet 인젝터의 연소성능 예측에 관한 실험적 연구)

  • Kim, J.W.;Park, H.H.;Han, J.S.;Kim, S.J.;Kim, Y.
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.3 no.4
    • /
    • pp.44-50
    • /
    • 1999
  • For the prediction of combustion performance of the Unlike Impinging Quadlet Injector (OOOF type), mixing efficiency, mixing characteristic velocity, and efficiency of mixing characteristic velocity were obtained from the cold test. Water/kerosene were used for simulants, The momentum ratio of oxidizer and fuel were mixing correlating parameter. Orifice discharge coefficient, spray pattern and mass distribution were measured. As a result, invasion-depth had strong effect on mixing efficiency, mixing characteristic velocity, and efficiency of mixing characteristic velocity. Mixing efficiency and efficiency of mixing characteristic velocity showed maximum value for momentum ratio 1.67(TMR = 2.5), and fuel rich state showed larger decreasing ratio than oxidizer rich state.

  • PDF

Parameter and Brightness Characteristic Analysis of Antena for Efficiency Improvement on Electrodeless Fluorescent Lamp (무전극 램프의 효율향상을 위한 안테나의 파라미타 특성 및 휘도특성)

  • Yang, Jong-Kyung;Choi, Gi-Seung;Pack, Gwang-Hyeon;Choi, Yong-Sung;Lee, Jong-Chan;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.11a
    • /
    • pp.531-534
    • /
    • 2004
  • In Recent, it became necessary to develope the technology about electrodeless fluorescent lamp according to demand of the electodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electordeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter. So it is of the utmost importance to design antena and inverter Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electordeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density

  • PDF

Modeling of The Ni-MH Battery Source and Development of The Charger.Discharger System (Ni-MH 전지전원의 모델링과 충.방전 장치 개발)

  • 김광헌;허민호;박영수;안재영;양승학;이일기
    • Proceedings of the KIPE Conference
    • /
    • 1998.07a
    • /
    • pp.433-437
    • /
    • 1998
  • Equalize SOC of the cell which effect on the charge.discharge ability and the efficiency of the battery, through the charge.discharge characteristic test of the battery source, and develope the high efficiency charge.discharge system in the series HEV have a constant engine-generator output. For this, in this paper, establish the electrical model and the condition of high efficiency charge.discharge, and proposed the improvement method of charge.discharge characteristic in the battery source that consist of twenty Ni-MH cells connected serial/parallel

  • PDF

Optimum Design of a Geometrically Asymmetric Trapezoidal Fin Based on the Fixed Fin Base Height (고정된 핀 바닥 높이에 기준한 기하학적 비대칭 사다리꼴 핀의 최적 설계)

  • Kang, Hyung-Suk
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.16 no.6
    • /
    • pp.81-87
    • /
    • 2008
  • A geometrically asymmetric trapezoidal fin with variable fin base thickness and height is optimized based on the fixed fin base height using a one-dimensional analytic method. The temperature profile along the normalized X position in the fin is presented. For the fixed fin base height, the optimum heat loss, fin length and efficiency as a function of inside fluid convection characteristic number, fin base thickness and height, fin shape factor, convection characteristic numbers ratio and ambient convection characteristic number are represented. One of the results shows that the effect of fin base height and ambient convection characteristic number on the optimum values is remarkable.