• Title/Summary/Keyword: single-pass

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Microstructural Evolution during the Equal Channel Angular Pressing of Ti-6Al-4V Alloy (Ti-6Al-4V 합금의 ECAP 가공시 미세 조직의 변화 연구)

  • 고영건;정원식;신동혁;이종수
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.05a
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    • pp.177-180
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    • 2002
  • The effects of pressing temperatures on the formability and the microstructural evolution during equal channel angular pressing (ECAP) of lamellar Ti-6Al-4V alloy were investigated in this study. ECAP above isothermally 600$^{\circ}C$ was successful without producing any noticeable segments at the specimen surfaces after a single pass of pressing. After 4 passes of ECA pressing, lamellar microstructures were significantly refined revealing equiaxed grains of 0.3$\mu\textrm{m}$ in diameter consisting of high angle grain boundaries. Also these ultrafine grains were relatively stable with little grain growth when annealed up to 600$^{\circ}C$ for 1hour.

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Microstructures and Impact Properties of 500mm Single Pass Electrogas Weldment for EH36 TMCP steels (EH36 TMCP강의 50mm 1 패스 일렉트로가스 용접부의 조직 및 충격특성)

  • 이해우;고대은
    • Journal of Welding and Joining
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    • v.17 no.3
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    • pp.96-101
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    • 1999
  • Microstructures and mechanical properties of weldments were studied for EH36 TMCP higher-strength hull steel with electrogas welding jprocess. In case of a newly designed EH36 TMCP steel for large heat input welding process, the Microstructures of HAZ shows more narrow width of grain coarsed region than that of conventional EH36 TMCP weldments, the amount of acicular ferrite, which is beneficial to impact toughness, increased while the amount of grain-boundary ferrite decreased. Charpy V-notched impact tests show that a newly designed EH36 TMCP steel weldment satisfies all the requirement of specifications, especially at the fusion line +2mm where the conventional EH36 TMCP steel fails to exceed the requirement.

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Application of a Brake Pressure Restriction Valve to a Motorcylce ABS (제동압력 제한밸브의 모터싸이클 ABS에의 적용)

  • 지동익;류제하;김호수;임재우;박종혁
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.130-136
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    • 2001
  • This paper presents an of a brake pressure restriction valve to a motorcycle anti-lock brake system(ABS). In the conventional anti-lock brake system of automobiles, slip ratio as a control variable is actively controlled, which requires wheel speed sensors, ECU, and a pressure modulator. In the ABS valve that has been developed for use in motorcycles, however, the brake pressure that is close to the wheel locking pressure is preset by simple exercises and then the valve just allows to pass the wheel locking pressure and cutoff the remaining pressure. Simulation studies with a single wheel braking dynamics and lumped chassis model show that the pressure restriction valve has basic ABS functions as well as some robustness properties for the uncertain load and road conditions as well as various initial braking speeds. Field tests also show that the pressure restriction valve avoids the wheel locking effectively.

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An Experimental Study on the Flow Characteristics ofa Supersonic Turbine Cascade as Pressure Ratio

  • Cho, Jong-Jae;Jeong, Soo-In;Kim, Kui-Soon;Lee, Eun-Seok
    • International Journal of Aeronautical and Space Sciences
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    • v.5 no.2
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    • pp.9-17
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    • 2004
  • In this paper, a small supersonic wind tunnel was designed and built to studythe flow characteristics of a supersonic impulse turbine cascade by experiment. Theflow was visualized by means of a single pass Schlieren system. The supersoniccascade with 3-dimensional supersonic nozzle was tested over a wide range ofpressure ratio. Highly complicated flow patterns including shocks, nozzle-cascadeinteraction and shock boundary layer interactions were observed.

A Study on Individual Tap-Power Estimation for Improvement of Adaptive Equalizer Performance

  • Kim, Nam-Yong
    • Journal of electromagnetic engineering and science
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    • v.4 no.1
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    • pp.23-29
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    • 2004
  • In this paper we analyze convergence constraints and time constant of IT-LMS algorithm and derive a method of making it's time constant independent of signal power by using input variance estimation. The method for estimating the input variance is to use a single-pole low-pass filter(LPF) with common smoothing parameter value, θ. The estimator is with narrow bandwidth for large θ but with wide bandwidth for small θ. This small θ gives long term average estimation(low frequency) of the fluctuating input variance well as short term variations (high frequency) of the input power. In our simulations of multipath communication channel equalization environments, the method with large θ has shown not as much improved convergence speed as the speed of the original IT-LMS algorithm. The proposed method with small θ=0.01 reach its minimum MSE in 100 samples whereas the IT-LMS converges in 200 samples. This shows the proposed, tap-power normalized IT-LMS algorithm can be applied more effectively to digital wireless communication systems.

A Study on a New Measurement Method of the Microstrip Parallel Coupled Lne Parameters (마이크로스트립 평행 결합선로 파라미터의 새로운 측정방법에 관한 연구)

  • Chang, Ik-Soo;Yoon, Young-Chul;Ahn, Dal
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.2
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    • pp.139-143
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    • 1988
  • A new measurement method of coupled transmission line characteristics is described. This method presents precision values of even-and odd-mode impedances as well as effective dielectric constants of symmetric parallel coupled microstrip lines from the scalar quantities obtained by transmission coefficients at two different resonance frequencies. Especially these values include dispersion effects in the measured frequency band. The measured impedances and effective dielectric constants of actually fabricated coupled lines on the Teflon substrates with low dielectric constants are good agreement with predicted values. And the experimental pass band characteristics of single section resonator by using previously designed coupled lines agree well with theoretical values.

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Development of Foundation of Urban Overpass for Bimodal Tram System (바이모달 트램 운행을 위한 도심지 고가구조물 기초형식 개발)

  • Kang, Tae-Sik;Bae, Eul-Ho;Park, Young-Kon;Yoon, Hee-Taek
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.194-198
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    • 2008
  • The necessities of development of foundation having minimized occupying area and construction time are required for overpass in the downtown area by which bimodal tram will pass a crossway. We are studying a single column drilled pier foundation which is continuous from pier to pile foundation. Due to the increased resisting moment by reinforced steel which is ranged from the upper part of pile to lower part of column above ground, it can be possible to make a smaller pile-section and lessen the bar reinforcing. And for the excavation work is possible with smaller equipment, this foundation has a improved constructability and economical efficiency. This foundation needs smaller amount of concrete and has a small self-weight. It has an effect on improving resistance against earthquake due to improved ductility in addition to improved rigidity by interaction between concrete and steel.

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The Study of Car Detection on the Highway using YOLOv2 and UAVs (YOLOv2와 무인항공기를 이용한 자동차 탐지에 관한 연구)

  • Seo, Chang-Jin
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.67 no.1
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    • pp.42-46
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    • 2018
  • In this paper, we propose fast object detection method of the cars by applying YOLOv2(You Only Look Once version 2) and UAVs (Unmanned Aerial Vehicles) while on the highway. We operated Darknet, OpenCV, CUDA and Deep Learning Server(SDX-4185) for our simulation environment. YOLOv2 is recently developed fast object detection algorithm that can detect various scale objects as fast speed. YOLOv2 convolution network algorithm allows to calculate probability by one pass evaluation and predicts location of each cars, because object detection process has simple single network. In our result, we could find cars on the highway area as fast speed and we could apply to the real time.

FSW Process Optimization for Al 2519 Alloys and Its Joint Characteristics(II) (후육 고강도 Al 2519합금의 FSW 접합기술 및 접합부 특성(II))

  • Kim, Heung-Ju;Jang, Ung-Seong;Yang, Gwang-Ha;Bang, Han-Seo
    • Proceedings of the KWS Conference
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    • 2005.06a
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    • pp.174-176
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    • 2005
  • On the basis of successful experiences and data from author's past experimental results of friction stir welding on thin aluminum plates, thick aluminum plate of high strength 2000 series has been carried out in this study. For various combination of rotating speed, welding speed and tool (RIWRC38-C) shape, the butt welded specimens has been prepared to check the metallurgical characteristics, hardness distributions and defects. From the results, feasible welding conditions have been obtained as 450 rpm rotating speed and 5 mm/min welding speed. Using these optimum welding parameters, 38.1mm-thickness A2519-T87 plates have been FSWelded in single pass. A good weld surface appearance and defects free weld zone has been observed in X-ray inspection. Softened region has been generated by dissolution of precipitates and coarsened microstructure in the stir zone after FSWeld.

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A Study on the Challenge of a Arbitrator (중재인의 기피에 관한 고찰)

  • 이명우
    • Journal of Arbitration Studies
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    • v.13 no.2
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    • pp.403-424
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    • 2004
  • In the solutions of civil disputes, there are decision of a court and alternative dispute resolution. Arbitration is one of alternative dispute resolutions. The decision of a court is the compulsory settlement and the solution by citizenship between two opposing parties, but arbitration is the autonomous and voluntary settlement by a private person, that is arbitrator. Besides these points, arbitration has various features in comparison with a decision of a court. The procedure of arbitration is not open to the public and single trial system guarantees speedy solution of disputes In the procedure of arbitration, arbitrator who pass judgement is selected and appointed by the parties to an affair. And there are questions how the arbitrator to become independent from them. Because Arbitration is not agreed solution which based on the concession between opposing two parties but imposed solution which is alike decision of a court. This study illustrates the system of challenge on arbitrator to guarantee independence of arbitrators.

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