• 제목/요약/키워드: reduction device

검색결과 1,288건 처리시간 0.028초

중합제 첨가에 의한 항력 감소 효과에 관한 실험적 연구 (Experimental Investigation of Drag Reduction by Polymer Additives)

  • 성형진;위장우;권순홍;전호환
    • 한국해양공학회지
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    • 제16권4호
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    • pp.1-6
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    • 2002
  • Experimental investigation of drag reduction by adding a polymer additive(polyacrylamid, N-401P) into water is carried out in a Circular Water Channel. The effect of viscosity, surface roughness and degradation as a function of running time is also measured with varying the concentration of polymer additives(20ppm,100ppm) and Reynolds numbers. Near and far wakes past a circular cylinder are observed by LDV. Drag forces are measured with a strain-gaged device. The experimental results show that around 5%-30% of drag reduction with the polymer solution are observed. The larger effects of drag reduction can be found at low range of Reynolds number, more roughened surface cylinder. The effect of polymer solution for near wakes is larger than for far wakes.

Suppression of Gate Oxide Degradation for MOS Devices Using Deuterium Ion Implantation Method

  • Lee, Jae-Sung
    • Transactions on Electrical and Electronic Materials
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    • 제13권4호
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    • pp.188-191
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    • 2012
  • This paper introduces a new method regarding deuterium incorporation in the gate dielectric including deuterium implantation and post-annealing at the back-end-of-the process line. The control device and the deuterium furnace-annealed device were also prepared for comparison with the implanted device. It was observed that deuterium implantation at a light dose of $1{\times}10^{12}-1{\times}10^{14}/cm^2$ at 30 keV reduced hot-carrier injection (HCI) degradation and negative bias temperature instability (NBTI) within our device structure due to the reduction in oxide charge and interface trap. Deuterium implantation provides a possible solution to enhance the bulk and interface reliabilities of the gate oxide under the electrical stress.

휴대폰용 일체형 음향 및 진동 발생장치 개발을 위한 연구 (Study on the Development of Integrated Vibration and Sound Generator)

  • 신태명;안진철
    • 한국소음진동공학회논문집
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    • 제13권11호
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    • pp.875-881
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    • 2003
  • The received signal of a mobile phone is normally sensed through two independent means which are the sound generation of a speaker and vibration generation of a vibration motor. As an improvement scheme to meet the consumer's demand on weight reduction and miniaturization of a mobile phone, the design and development of an integrated vibration and sound generating device are performed in this research. To this purpose, the optimal shapes of the voice coil. the permanent magnet and the vibration plate are designed, and the excitation force applied to the vibration system of the new device is estimated and verified through theoretical analyses, computer simulation, and experiments using an expanded model. In addition, vibration performance comparison of the device with the existing vibration motor is performed, and from the overall process, therefore, the method and procedure for the vibration performance analysis of the integrated vibration and sound generating device are established.

TightRope$^{TM}$ Device를 이용한 족근 중족 관절 손상의 치료(1예 보고) (Lisfranc Injury Repair with the TightRope$^{TM}$ Device (A Case Report))

  • 조재호;오인석
    • 대한족부족관절학회지
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    • 제15권4호
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    • pp.243-246
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    • 2011
  • Lisfranc injury is complex and difficult to treat. Making the correct diagnosis and achieving an anatomical reduction are important factors in regard to achieving a favorable outcome with this injury. We describe a new technique that we have found to be useful for stabilizing Lisfranc injury. This method is relatively fast and simple, and it provides non-rigid fixation. Also, it eliminates the need for implant removal. To date, we have achieved predictable results for stabilizing and treating this injury with the use of a $TightRope^{TM}$ Device, instead of traditional interfragmental screw fixation. In this report, we describe a case in which this method was used with satisfactory short-term results.

InAlAs/InGaAs/GaAs 100 nm-게이트 MHEMT 소자의 에피 구조 최적화 설계에 관한 연구 (Optimization Study on the Epitaxial Structure for 100nm-Gate MHEMTs with InAlAs/InGaAs/GaAs Heterostructure)

  • 손명식
    • 반도체디스플레이기술학회지
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    • 제10권4호
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    • pp.107-112
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    • 2011
  • This paper is for improving the RF frequency performance of a fabricated 100nm ${\Gamma}$-gate MHEMT, scaling down vertically for the epitaxy-structure layers of the device. Hydrodynamic simulation parameters are calibrated for the fabricated MHEMT with the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}$As heterostructure grown on the GaAs substrate. With these calibrated parameters, simulations for the vertically-scaled epitaxial layers of the device are performed and analyzed for DC/RF characteristics, including the quantization effect due to the thickness reduction of InGaAs channel layer. A newly designed epitaxy-structure device shows higher extrinsic transconductance, $g_m$ of 1.556 S/mm, and higher frequency performance, $f_T$ of 222.5 GHz and $f_{max}$ of 849.6 GHz.

KTX 감속기 유지보수 정책에 대한 고찰 (A study of maintenance measures of the KTX decelerator)

  • 정도원;이영엽;김은실
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2009년도 춘계학술대회 논문집
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    • pp.1191-1197
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    • 2009
  • KTX decelerator is a device to fulfil a role of transmission of turning force to reduction device of an axle by serrate device. Currently, KTX decelerator's TBO(Time Between Overhaul) has 3 years cycle. As for the dissembly maintenance of a device, its maintenance is conducted every 1.4M kms. In this study, since opening of KTX, we analyzed reliability, maintainability, availability of KTX decelerator by researching historical records of maintenance of the decelerator, and based on above data, investigated whether its TBO cycle and maintenance works properly or not And we considered maintenance policies of KTX decelerator to improve efficiency in maintenance in the future.

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Deep submicrometer PMOSFET의 hot carrier 현상과 소자 노쇠화 (Hot carrier effects and device degradation in deep submicrometer PMOSFET)

  • 장성준;김용택;유종근;박종태;박병국;이종덕
    • 전자공학회논문지A
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    • 제33A권4호
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    • pp.129-135
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    • 1996
  • In this paper, the hot carrier effect and device degradation of deep submicrometer SC-PMOSFETs have been measured and characterized. It has been shown that the substrate current of a 0.15$\mu$m PMOSFET increases with increasing of impact ionization rate, and the impact ionization rate is a function of the gate length and gate bias voltage. Correlation between gate current and substrate current is investigated within the general framework of the lucky-electron. It is found that the impact ionization rate increases, but the device degradation is not serious with decreasing effective channel length. SCIHE is suggested as the possible phusical mechanism for enhanced impact ionization rate and gate current reduction. Considering the hot carrier induced device degradation, it has been found that the maximum supply voltage is about -2.6V for 0.15$\mu$m PMOSFET.

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Novel electrode architecture for transparent organic thin-film transistors

  • Chen, Fang-Chung;Chen, Tung-Hsien;Lin, Yung-Sheng
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.194-197
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    • 2006
  • One novel electrode-architecture has been adapted to fabricate transparent OTFTs. The device has more than 70% transmittance, yet reminds high performance. Furthermore, we also use transfer line method to prove that the device performance enhancement indeed contributes from the reduction of the contact resistances. It is anticipated that the transparent OTFTs would be very suitable to be the driving circuits for liquid crystal displays (LCDs).

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