• Title/Summary/Keyword: Duty rate

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An Accurate Gate-level Stress Estimation for NBTI

  • Han, Sangwoo;Lee, Junho;Kim, Byung-Su;Kim, Juho
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.13 no.2
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    • pp.139-144
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    • 2013
  • Negative bias temperature instability (NBTI) has become a major factor determining circuit reliability. The effect of the NBTI on the circuit performance depends on the duty cycle which represents the stress and recovery conditions of each device in a circuit. In this paper, we propose an analytical model to perform more accurate duty cycle estimation at the gate-level. The proposed model allows accurate (average error rate: 3%) computation of the duty cycle without the need for expensive transistor-level simulations Furthermore, our model estimates the waveforms at each node, allowing various aging effects to be applied for a reliable gate-level circuit aging analysis framework.

Bipolar Integrated Optical Link Receiver with Low Supply Voltage (바이폴라 집적된 저전압구동 광연결 수신기)

  • 장지근;이상열
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.4
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    • pp.9-14
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    • 2003
  • The new optical link receiver with data transfer rate higher than 10Mbps at the supply voltage of 1.8V was designed and fabricated using bipolar technology. The fabricated IC showed the dissipation current of 4.6mA under high level input voltage of 1.5V. The high level output voltage($V_{OH}$) and the low level output voltage($V_{OL}$) were 1.15V and 0V, respectively, for a given 10 Mbps signal which has duty ratio of 50%, $V_{IL}$(low level input voltage) of 0.5V, and $V_{IH}$(high level input voltage) of 1.5V, The duty ratio of output waveform was 52.6%. The rising time(t$_{r}$) and the falling time(t$_{f}$) were 9.5ns and 6.8ns, respectively. The propagation delay difference($t_{PHC}-t_{PLH}$) and the jitter($t_j$) were 11.7ns and 4.3ns, respectively.y.

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Performance Characteristics of an Electronically Controlled EGR Valve for Diesel Engines (디젤엔진용 전자식 EGR 밸브의 성능 특성)

  • Chung, Jin-Eun;Chin, Young-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.2
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    • pp.185-188
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    • 2007
  • Lately, the modulated EGR system that includes EGR valve and EGR cooler is being installed in diesel engines fur the purpose of the simultaneous reduction of NOx and PM. In this study. we designed and constructed a test bench for the performance evaluation of the modulated EGR system, and tested an electronically controlled EGR valve for 2.0 L diesel engines. The performance of the EGR valve was evaluated in terms of the valve lift behavior. the valve opening/closing response, and the mass flow rate through the valve. The valve lift with respect to the duty ratio of PWM signal was non-linear, and followed a different path fur valve opening and closing, that is, hysteresis. The valve opening response was concluded satisfactory falling within the usual standard response time. For the duty ratio of 40 to 60%, the mass flow rate through the valve was observed to depend on the pressure difference across the valve as well as the duty ratio, while it solely depended on the pressure difference fur the duty ratio above 60%.

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The evaluation of diesel emission reduction characteristics by DOC in light-duty vehicle (소형디젤산화촉매의 배출가스 성능평가)

  • 엄명도;류정호;임철수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.8
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    • pp.34-42
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    • 1999
  • In late 1997, the portion of registered light-duty diesel vehicle was 25.3% and its emission rate was 17.1% in Korea. Especially, diesel particulate matters(DPM) and NOx are hazardous air pollutants to human health and environment in urban area. The reduction technologies of exhaust emissions from diesel engines are improvement of engine combustion, fuel quality and development of diesel exhaust after treatment , In this study , a light-duty diesel oxidation catalyst(DOC) that is one of the diesel exhaust after treatment was made for performance evaluation and the emission characteristics were tested on CVS-75 mode. And the analysis of the particle size distribution with scanning mobility particle 100, 67.6% and 66.7, 10.0% for Pt and Pt-V catalyst .And for Pt catalyst, the PM increased 7.8% because of increasing sulfate but Pt-V catalyst reduced the PM to 23.0% . Test results of particle size distribution showed that peak values of number and mass densities are respectively 100∼200nm their distribution trend independent of vehicle speed.

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Exergy-Based Performance Analysis of Heavy-duty Gas Turbine in Part-Load Operating Conditions (엑서지를 이용한 대형 발전용 가스터빈의 부분부하 성능 분석)

  • Song, T.W.;Sohn, J.L.;Kim, J.H.;Kim, T.S.;Ro, S.T.
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.751-758
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    • 2001
  • Exergy concept is applied to the analysis of part-load performance of gas turbine engine. Exergy is a useful tool to find the source of irreversibility in thermal system. In this study, details of the performance characteristics of a heavy-duty gas turbine, l50MW-class GE 7FA model, are described by theoretical investigations with exergy analysis. Result shows that exergy destruction rate of gas turbine increases with decreased load, which means increase of irreversibility. Also, it is found that variations of IGV angle and amount of cooling air for turbine blades are closely related to the inefficiencies of compressor and turbine, respectively.

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Large Thrust Linear Motor for Low-duty-cycle Operation (고추력 저가동률 리니어모터에 관한 연구)

  • Bang, Yeong-Bong;Lee, Gyeong-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.8
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    • pp.161-171
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    • 2002
  • This paper presents a linear motor, which generates large thrust with a low operating rate. In industrial fields there is a need for actuators that work with a low duty cycle but generate large thrusts. An example of such a case is provided by the actuators for ejector mechanisms in electric injection molding machines. The ordinary LSM (linear synchronous motor) is unsuitable for this large-thrust and low-operating-rate usage, because of its large size and high cost. This paper contains experimental results on linear motors that can generate large thrusts for a short time, and which can be cheaply produced. The described linear motor could be contained space of $250mm \times250mm\times 250mm$ and generate a maximum thrust of about 20000 N at a current of 250 A.

The analysis of RF dosimetric uncertainties by using statistical method at in-vivo and in-vitro experiments (RF 전자기장 생체 영향 실험에서 통계적 방법을 통한 전자기장 노출 불확실성 분석)

  • Choi, Sung-Ho;Kim, Nam
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.74-78
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    • 2003
  • This paper shows the dosimetric uncertainties of electromagnetic field at in-vivo and in-vitro experiments. For more accurate consequences of these researches, we have tried to find out any correlations among output power, power density and specific absorption rate(SAR) with the results of in-vivo, in-vitro tests and SAR reports of cellular phone and PDA. In the case of in-vivo tests, the power density has close statistical correlations with SAR value and in the event of in-vitro tests, the output power has considerable statistical correlations with SAR containing duty factor. On the other hand, we found that both power density and output power don't have any close correlations with SAR. And, we obtained fitted regression form among frequency, power density and SAR containing duty factor through multiple linear regression analysis.

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An experimental study on flame characteristics with periodical fuel supply (주기적 연료공급에 따른 화염거동에 관한 실험적 연구)

  • 이태원;이동혁;정석호
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.50-60
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    • 1992
  • Flame characteristics of periodic fuel jets were studied experimentally by supplying the fuel periodically using solenoid valve. Flame was observed using a high speed camera, a 35 mm camera and a cathetometer. Hot-wire ananometer was used to meature the speed of fuel flow at the nozzle exit to analyze the flow characteristics. Various types of flame characteristics such as the flame lift-off and extinction were observed for different ranges of period, duty, and flow rate, but the flame shape was not affected much by the variation in the flow rate. Decreasing duty of the pulses applied to the solenoid valve promotes lift-off and enhances premixed flame characteristics.

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The Study on Estimating Life Cycle of 2.5 Inch Hard disk base on PC using enviroment (PC 사용 환경에 기반한 2.5 인치 하드 디스크의 수명주기 예측에 대한 연구)

  • Cho, Euy-Hyun;Park, Jeong-Kyu;Lee, Min-Woo;Kwon, Soon-Mu
    • Journal of Digital Contents Society
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    • v.15 no.2
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    • pp.301-308
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    • 2014
  • The mass storage of data and the importance of storage capacity lately has emerged. In this paper, we suggest the new method which estimate life cycle from acceleration life test about 2.5 inch hard disk driver as mass storage, which minimize the difference between real market annual failure rate and estimated failure rate. we obtain market transfer capacity per hours from returned 2.5inch hard disk drives about 309 numbers and accelerating transfer capacity per hours from acceleration life test. we calculate acceleration factor about duty cycle and estimate annual failure rate from failure rate and acceleration factors: temperature acceleration factor, duty cycle acceleration factor, the transfer capacity per hour represent the 93.4 % of user is 5.8 GB/hour, the transfer capacity per hour from acceleration life test is 81.4 GB/hour. the acceleration factor of duty cycle is 14.1. annual failure rate is stabilized at market one year after, annual failure rate is between 0.3 and 0.378. estimated annual failure rate is 0.4, so it is matched at 75~94 % between estimate annual failure rate and market annual failure rate. This study influence the estimate method of annual failure rate by the result of acceleration life cycle of manufacture.

Novel Fabrication and Testing of a Bubble-Powered Micropump (새로운 기포동력 마이크로펌프 제작 및 실험)

  • Jung, Jung-Yeul;Kwak, Ho-Young
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1196-1200
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    • 2004
  • Micropump is very useful component in micro/nano fluidics and bioMEMS applications. In this study, a bubble-powered micropump was fabricated and tested. The micropump consists of two-parallel micro line heaters, a pair of nozzle-diffuser flow controller and a 1 mm in diameter, 400 ${\mu}m$ in depth pumping chamber. The two-parallel micro line heaters with 20 ${\mu}m-width$ and 200 ${\mu}m-length$ were fabricated to be embedded in the silicon dioxide layer of a wafer which serves as a base plate for the micropump. The pumping chamber, the pair of nozzle-diffuser unit and microchannels including the liquid inlet and outlet port were fabricated by etching through another silicon wafer. A glass wafer (thickness of $525{\pm}15$ ${\mu}m$) having two holes of inlet and outlet ports of liquid serve as upper plate of the pump. Finally the silicon wafer of the base plate, the silicon wafer of pumping chamber and the glass wafer were aligned and bonded (Si-Si bonding and anodic bonding). A sequential photograph of bubble nucleation, growth and collapse was visualized by CCD camera. Clearly liquid flow through the nozzle during the period of bubble growth and slight back flow of liquid at the end of collapsing period can be seen. The mass flow rate was found to be dependent on the duty ratio and the operation frequency. As duty ratio increases, flow rate decreases gradually when the duty ratio exceeds 60%. Also as the operation frequency increases, the flow rate of the micropump decreases slightly.

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