• 제목/요약/키워드: rate constant(k)

검색결과 3,147건 처리시간 0.033초

Control Charts for Constant Failure Rate of System

  • 조교영;이옥희
    • Journal of the Korean Data and Information Science Society
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    • 제13권2호
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    • pp.147-156
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    • 2002
  • In this paper, we propose EWMA control charts using the life time data for the system with the constant failure rate, which were drawn from the fixed sampling interval without replacement(with replacement), and investigate the power of detection of EWMA by comparing ARL of EWMA control charts with one of Shewhart control charts.

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LASER ISDG법으로 관찰한 용접재에서의 피로크랙개구거동

  • 송삼흥;김현;최진호
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 추계학술대회 논문집
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    • pp.263-268
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    • 2001
  • The constant .DELTA. K fatigue tests are performed in SS41 and its weldment. The LASER ISDG method is used in determination of crack opening ratio. This method is more precise than indirect measurement method, faster and easier than other direct measurement method. And obtained results are followed 1) Crack opening ratio U is proportional to fatigue crack growth rate da/dN at constant .DELTA. K 2) Fatigue crack growth rate da/dN in weldment increases in weld metal and heat affected zone, decreases in base metal as crack grows.

Control Charts for Constant Failure Rate of System

  • Cho, Gyo-Young;Lee, Ok-Hee
    • 한국데이터정보과학회:학술대회논문집
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    • 한국데이터정보과학회 2002년도 춘계학술대회
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    • pp.141-149
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    • 2002
  • In this paper, we propose EWMA control charts using the life time data for the system with the constant failure rate, which were drawn from the fixed sampling interval without replacement (with replacement), and investigate the power of detection of EWMA by comparing ARL of EWMA control charts with one of Shewhart control charts.

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Image Independent Driving Power Reduction for High Frame Rate LCD Televisions

  • Nam, Hyoung-Sik;Shim, Jae-Hoon
    • ETRI Journal
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    • 제34권3호
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    • pp.470-473
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    • 2012
  • In this letter, the constant driving power reduction ratio has been achieved for column drivers regardless of the input image by incorporating a new static power reduction scheme into the previous dynamic power reduction method. The measured power reduction ratio is around 50% for a 120 Hz liquid crystal display panel in such cases of still input video and fallback.

PCW-PNN-PZT계 세라믹의 유전 특성에 관한 연구 (A Study on Dielectric Properties of PCW-PNN-PZT ceramics)

  • 신혜경;이성호;정보람;배선기
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.51-53
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    • 2005
  • This study was to measure the minuteness structure, dielectric properties of 0.03PCW-0.07PNN-0.9PZT ceramics according to sintering temperature manufacture the specimens with a general method. The results of this study were gotten such as follows. The crystal structure of ceramic changed the rombohedral structure into teteragonal structure according to rising sintering temperature in XRD. Dielectric constant at $20^{\circ}C$ showed its maximum value 510.599 in specimens sintered at $1100^{\circ}C$ and dielectric loss showed its minimum value 7.43% in specimens sintered at $1100^{\circ}C$. The variation rate of dielectric constant according to the change of frequency showed its minimum value 0.029/kHz at $1100^{\circ}C$. The variation rate of dielectric constant according to the change of temperature showed its minimum value $1.40/^{\circ}C$ at $1500^{\circ}C$.

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MUSCLE PROTEIN SYNTHESIS IN VITRO IN CHICKS FED A LOW-PROTEIN DIET

  • Kita, K.;Kuzuya, Y.;Matsunami, S.;Okumura, J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제9권2호
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    • pp.171-174
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    • 1996
  • Muscle protein synthesis in vitro was measured in chicks fed low-protein(10% CP) and control(20% CP) diets. Right leg muscles (M. gastrocnemius) were mounted on a support made of stainless steel to stretch in constant tension, whereas left leg muscles were unmounted. Both leg muscles were incubated in Dulbecco's modified Eagle's medium including L-[$4-^3H$] phenylalanine for 60 min to measure in vitro protein synthesis. There was no significant difference in fractional synthesis rate(FSR) of muscle protein between both dietary protein levels, whereas FSR with stretch in constant tension was significantly higher than that without constant tension due to an increase in the absolute synthesis rate(ASR) per unit RNA(the efficiency of RNA to synthesize protein). The ASR of muscle protein in chicks fed the control diet was significantly higher than that in the low-protein diet group.

보강성 충전제가 첨가된 SBR/BR 블렌드의 가황특성에 관한 연구 (A Study on the Vulcanization Characteristics of SBR/BR Blends Containing Reinforcing Fillers)

  • 이석
    • Elastomers and Composites
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    • 제33권4호
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    • pp.274-280
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    • 1998
  • 가황반응에 대한 반응차수, 반응속도상수 및 활성화에너지, 가교결합에 의한 가교밀도 및 탄성상수를 동일한 가황시스템하에서 실리카와 카본블랙을 함유한 SBR/BR 블렌드에 대하여 조사하였다. 반응차수는 충전제 종류에 관계없이 1차 반응이었으며, 카본블랙이 첨가된 배합고무는 실리카가 첨가된 배합고무보다 반응속도가 빠르게 나타났다. 그러나 활성화에너지는 충전제 종류 및 고무 블렌드 조성에 관계없이 일정하게 나타났다. 가교밀도 및 탄성상수는 고무와 카본블랙간의 강한 상호작용으로 인해 카본블랙이 첨가된 조성물에서 높게 나타났다. 한편, 고무 블렌드중 부타디엔 고무 함량이 증가할수록 가교밀도 및 탄성상수는 감소하였다. 가황고무중 결합 황 함량 비교결과, 실리카가 첨가된 조성물중 일정한 결합 황 함량은 반응시작 후 20분 후에 나타났으나, 카본블랙이 첨가된 조성물은 10분 후에 나타났다. 또한 실리카가 첨가된 조성물은 카본블랙이 첨가된 조성물에 비해 반응 유도시간($t_2$) 및 최적 가황시간($t_{90}$)이 길게 나타났다.

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산화 마그네슘 박막의 스퍼터 제조기술 (Sputtering technique for magnesium oxide thin films)

  • 최영욱
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1560-1561
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    • 2006
  • A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of $10{\sim}50\;kHz$ and $10{\sim}60%$, respectively. The deposition rate increased with rising incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW.

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Reaction Dynamics of CH3 + HBr → CH4 + Br at 150-1000 K

  • Ree, Jongbaik;Kim, Yoo Hang;Shin, Hyung Kyu
    • Bulletin of the Korean Chemical Society
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    • 제34권8호
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    • pp.2473-2479
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    • 2013
  • The kinetics of the radical-polar molecule reaction $CH_3+HBr{\rightarrow}CH_4+Br$ has been studied at temperatures between 150 and 1000 K using classical dynamics procedures. Potential energy surfaces constructed using analytical forms of inter- and intramolecular interaction energies show a shallow well and barrier in the entrance channel, which affect the collision dynamics at low temperatures. Different collision models are used to distinguish the reaction occurring at low- and high-temperature regions. The reaction proceeds rapidly via a complex-mode mechanism below room temperature showing strong negative temperature dependence, where the effects of molecular attraction, H-atom tunneling and recrossing of collision complexes are found to be important. The temperature dependence of the rate constant between 400 and 1000 K is positive, the values increasing in accordance with the increase of the mean speed of collision. The rate constant varies from $7.6{\times}10^{-12}$ at 150 K to $3.7{\times}10^{-12}$ at 1000 K via a minimum value of $2.5{\times}10^{-12}\;cm^3\;molecule^{-1}\;s^{-1}$ at 400 K.

제올라이트 A의 결정화 속도에 대한 결정화 조건의 영향 (The Effect of Crystallization Condition on the Crystallization Rate of Zeolite A)

  • 정경환;서곤
    • 공업화학
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    • 제4권1호
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    • pp.94-102
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    • 1993
  • 제올라이트 A의 결정화 과정에서 온도, $Na_2O$$SiO_2$ 조성의 영향을 조사하였다. 각 결정화 조건에서 결정화 곡선과 최종 생성물의 결정크기 분포를 조사하고 반응 경로 모델을 이용하여 결정화 속도를 구하였다. 결정화 과정은 길이 성장 속도상수가 결정 크기와 무관하게 일정하고 무정형 고형 겔과 용해된 반응물이 평형을 이룬다는 가정으로 잘 모사되었으며, 실험결과와 비교하여 길이성장 속도상수 등을 결정할 수 있었다. 온도가 높아지면 길이성장 단계와 용해된 반응물의 분율이 커져서 결정화 속도가 커졌다. 반면 $Na_2O/H_2O$ 몰비가 커지면 성장단계는 촉진되지 않으나 용해된 반응물의 분율이 커졌으며 핵심생성이 촉진되었다. $SiO_2/Al_2O_3$ 몰비에 따라 용해된 반응물 분율과 핵심생성 속도가 달라진다. 각 결정화 조건에서 제올라이트 A의 길이성장 속도상수는 $0.07{\sim}0.24{\mu}m{\cdot}min^{-1}$로 추정되었으며 겉보기 활성화에너지는 $49kJ{\cdot}mol^{-1}$이었다.

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