• Title/Summary/Keyword: Time progress

검색결과 2,177건 처리시간 0.04초

Time progress of dark fermentation for biological hydrogen production using Chlamydomonas reinhardtii

  • 김지성;공경택;박대원;심상준;박태현;조경숙;정윤철
    • 한국생물공학회:학술대회논문집
    • /
    • 한국생물공학회 2003년도 생물공학의 동향(XII)
    • /
    • pp.162-163
    • /
    • 2003
  • 수소를 생산하는 암반응에서는 pH와 dry cell weight, 세포내의 starch 함유량이 시간에 따라 줄어들었다. 유기물은 시간에 따라 증가하였지만, 수소는 3일째에 생산이 최대치에 도달하였다.

  • PDF

자율신경계 활성도 측정 시스템 개발 (A development of measuring system for Autonomic Nervous Activity)

  • 이준하
    • 한국의학물리학회지:의학물리
    • /
    • 제11권2호
    • /
    • pp.141-146
    • /
    • 2000
  • 전력 스펙트럼 분석은 자율신경계 활성도를 정량화하기 위한 강력한 비침습적인 도구이다. 본 논문에서는 자율신경계의 활성도를 측정하기 위한 시스템을 개발하였다. 시스템에서는 환자의 안전을 고려 하여 분리 전원을 채택했다. 출력으로는 ECG 시간 변이와 호흡 시간 변이를 획득하였다. 시간 변이는 자율신경계와 관련한 질병을 발견하는 데 유용하다. 시험에 적용된 범위는 심전도는 30~240 bpm 그리고 호흡에서는 15~80bpm 을 적용하였다.

  • PDF

디젤 엔진 운전 조건에서 분무 연소 과정과 난류 화염 구조 특성에 대한 해석 (Characteristization of Spray Combustion and Turbulent Flame Structures in a Typical Diesel Engine Condition)

  • 이영재;허강열
    • 한국연소학회지
    • /
    • 제14권3호
    • /
    • pp.29-36
    • /
    • 2009
  • Simulation is performed to analyze the characteristics of turbulent spray combustion in a diesel engine condition. An extended Conditional Moment Closure (CMC) model is employed to resolve coupling between chemistry and turbulence. Relevant time and length scales and dimensionless numbers are estimated at the tip and the mid spray region during spray development and combustion. The liquid volume fractions are small enough to support validity of droplets assumed as point sources in two-phase flow. The mean scalar dissipation rates (SDR) are lower than the extinction limit to show flame stability throughout the combustion period. The Kolmogorov scales remain relatively constant, while the integral scales increase with decay of turbulence. The chemical time scale decreases abruptly to a small value as ignition occurs with subsequent heat release. The Da and Ka show opposite trends due to variation in the chemical time scale. More work is in progress to identify the spray combustion regimes.

  • PDF

원자력발전소 고압전동기 모선 잔류전압 특성 (Motor Bus Residual Voltage Characteristics at Nuclear Power Plant)

  • 변상윤;김순용
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2009년도 제40회 하계학술대회
    • /
    • pp.662_663
    • /
    • 2009
  • Motor bus transfer involves the process of transferring a bus that has several critical motors to an alternate source of power when the main normal power source feeding them is interrupted. Bus transfer is a time-critical application in which the transfer progress depends on various parameters such as the type of motor, load on the motor at the time of transfer, inertia of the motor, and the combined open-circuit time constant of various motors present on the bus at the time of transfer. This paper present the result of modeling and simulation of nuclear power motor bus using ETAP(Electrical Transient Analyzing Program) program for motor and motor bus residual voltage decay characteristics.

  • PDF

와이블 지연시간 모형 하에서의 FMEA를 위한 고장원인의 위험평가 (Risk Evaluation of Failure Cause for FMEA under a Weibull Time Delay Model)

  • 권혁무;이민구;홍성훈
    • 한국안전학회지
    • /
    • 제33권3호
    • /
    • pp.83-91
    • /
    • 2018
  • This paper suggests a weibull time delay model to evaluate failure risks in FMEA(failure modes and effects analysis). Assuming three types of loss functions for delayed time in failure cause detection, the risk of each failure cause is evaluated as its occurring frequency and expected loss. Since the closed form solution of the risk metric cannot be obtained, a statistical computer software R program is used for numerical calculation. When the occurrence and detection times have a common shape parameter, though, some simple results of mathematical derivation are also available. As an enormous quantity of field data becomes available under recent progress of data acquisition system, the proposed risk metric will provide a more practical and reasonable tool for evaluating the risks of failure causes in FMEA.

High Precision Path Generation of an LCD Glass-Handling Robot

  • Cho, Phil-Joo;Kim, Hyo-Gyu;Kim, Dong-Il
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 2005년도 ICCAS
    • /
    • pp.2311-2318
    • /
    • 2005
  • Progress in the LCD industries has been very rapid. Therefore, their manufacturing lines require larger LCD glass-handling robots and more precise path control of the robots. In this paper, we present two practical advanced algorithms for high-precision path generation of an LCD glass-handling robot. One is high-precision path interpolation for continuous motion, which connects several single motions and is a reliable solution for a short robot cycle time. We demonstrate that the proposed algorithm can reduce path error by approximately 91% compared with existing algorithms without increasing cycle time. The second is real-time static deflection compensation, which can optimally compensate the static deflection of the handling robot without any additional sensors, measurement instruments or mechanical axes. This reduces vertical path error to approximately 60% of the existing system error. All of these algorithms have been commercialized and applied to a seventh-generation LCD glass-handling robot.

  • PDF

레이저 유도방식의 실시간 광음향 단층영상 기술 개발과 팬텀이미지 평가 (Development of Laser Induced Real Time Photoacoustic Tomography Imaging System and Phantom Evaluation)

  • 유상훈;신동호;송철규
    • 전기학회논문지
    • /
    • 제61권6호
    • /
    • pp.879-884
    • /
    • 2012
  • Photoacoustic Tomography (PAT) is a promising medical imaging modality by reason of its particularity. It combines optical imaging contrast of optical imaging with the spatial resolution of ultrasound imaging and can demonstrate change of biological feature in an image. For that reason, many studies are in progress to apply this technic for diagnosis. But, real-time PAT system is necessary to confirm a biological reaction induced by external stimulation immediately. Thus, we developed a real-time PAT system using linear array transducer and self-developed Data acquisition board (DAQ) resources, To evaluate the feasibility and performance of our proposed system, two type of phantom test were also performed. As a result of those experiments, the proposed system shows enough performance and confirm its usefulness.

RSFQ 논리회로의 개발과 회로설계에 대한 지연시간 고려 (Development of RSFQ Logic Circuits and Delay Time Considerations in Circuit Design)

  • 강준희;김진영
    • Progress in Superconductivity
    • /
    • 제9권2호
    • /
    • pp.157-161
    • /
    • 2008
  • Due to high speed operations and ultra low power consumptions RSFQ logic circuit is a very good candidate for future electronic device. The focus of the RSFQ circuit development has been on the advancement of analog-to-digital converters and microprocessors. Recent works on RSFQ ALU development showed the successful operation of an 1-bit block of ALU at 40 GHz. Recently, the study of an RSFQ analog-to-digital converter has been extended to the development of a single chip RF digital receiver. Compared to the voltage logic circuits, RSFQ circuits operate based on the pulse logic. This naturally leads the circuit structure of RSFQ circuit to be pipelined. Delay time on each pipelined stage determines the ultimate operating speed of the circuit. In simulations, a two junction Josephson transmission line's delay time was about 10 ps, a splitter's 14.5 ps, a switch's 13 ps, a half adder's 67 ps. Optimization of the 4-bit ALU circuit has been made with delay time consideration to operate comfortably at 10 GHz or above.

  • PDF

초음파 에너지 조사에 따른 바이오 디젤 특성 (Characteristics of Bio-diesel according to Irradiation for Ultrasonic Energy)

  • 박충열;최두석
    • 한국자동차공학회논문집
    • /
    • 제23권2호
    • /
    • pp.214-220
    • /
    • 2015
  • Since resources of fossil fuels are limited, development of alternative energies is emphasized and research on new-regenerative energy is actively in progress worldwide. In present research, physical and chemical characteristics of mixed fuel are analyzed in detail for the different mixture rate of conventional and bio-diesel and ultrasonic irradiation time. Experimental setup consists of ultrasonic generator, vibrator, horn, and reflector. Various physical and chemical characteristics of fuel are investigated for volumetric mixture rate of bio-diesel from 0 to 100%. As results, viscosity and surface tension is increased as mixture rate of bio-diesel is increased. Also, molecular splits and reunions are increased and decreased repeatedly after some period of time as ultrasonic energy irradiation time is increased. As conclusion of experiments, Olefin rate, Branch index, and Aromatic rate are influenced by ultrasonic irradiation time.

댐퍼의 두께와 재질 변화에 따른 초전도 선재에 미치는 자장특성 분석 (Analysis of Magnetic Field of Superconducting Winding According to the Changed Damper Thickness and Material)

  • 정재식;이상호;홍정표;조영식
    • 한국초전도ㆍ저온공학회논문지
    • /
    • 제14권3호
    • /
    • pp.5-8
    • /
    • 2012
  • Superconducting windings of synchronous machine have to be operated in below the critical temperature, critical current density and critical magnetic field. If one of these characteristics does not satisfied, then the quench occurred in superconducting winding. Especially the armature current dramatically increased as the superconducting generator is short-circuited at the rated load condition and magnetic field in field winding increased due to the armature current. Therefore, damper is required to reduce the magnetic field of field winding which increases reliability of the superconducting generator. Damper dimension can be decided by time constant[1-2]. In this paper the basic model is high-power and low-speed superconducting generator. Damper time constant was calculated from the changed damper thickness and material. Magnetic flux of field coil at the basic model and changed damper time constant model is analyzed.