• Title/Summary/Keyword: J-Q이론

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The Experimental Method of Measuring Q (Q의 실험적 측정법)

  • Kim, Dong-Hak;Lee, Jeong-Hyun;Kang, Ki-Ju
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.285-291
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    • 2003
  • An experimental method to measure Q-parameter in-situ is described. The basic idea comes from the fact that the side necking near a crack tip indicates the loss of stress triaxiality, which can be scaled by Q. From the out-of-plane displacement and the in-plane strain near the surface of side necking, stress field averaged through the thickness is calculated and then Q is determined from the difference between the stress field and the HRR field corresponding to the identical J-integral. To prove the validity, three-dimensional finite element analysis has been performed for a CT configuration with side-groove. Q-value which was calculated directly from the near-tip stress field is compared with that determined by simulating the experimental procedure according to the proposed method, that is, the Q-value determined from the lateral displacement and the inplane strain. Also, the effect of location where the displacement and strain are measured is explored.

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An Experimental Method for Measuring Q (Q의 실험적 측정법)

  • Kim, Dong-Hak;Lee, Jeong-Hyun;Kang, Ki-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.9
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    • pp.1607-1613
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    • 2003
  • An experimental method to measure Q-parameter in-situ is described. The basic idea comes from the fact that the side necking near a crack tip indicates the loss of stress triaxiality, which can be scaled by Q. From the out-of-plane displacement and the in-plane strain near the surface of side necking, stress field averaged through the thickness is calculated and then Q is determined from the difference between the stress field and the HRR field corresponding to the identical J-integral. To prove the validity, three-dimensional finite element analysis has been performed for a CT configuration with side-groove. Q-value which was calculated directly from the near-tip stress field is compared with that determined by simulating the experimental procedure according to the proposed method, that is, the Q-value determined from the lateral displacement and the in-plane strain. In addition, the effect of location where the displacement and strain are measured is explored.

Variation of the Fracture Resistance Curve with the Change of a Size in the CT Specimen (CT시험편의 크기 변화에 따른 파괴저항곡선의 변화)

  • Seok, Chang-Seong;Kim, Su-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.12
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    • pp.2963-2971
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    • 2000
  • In order to obtain more realistic fracture resistance curve, research is currently underway to introduce new parameter and to quantify the constraint effect. The objective of this study is to investigate the relationship between the constraint effect of a size(plane size and thickness) and the fracture resistance curve. In this paper fracture toughness tests were performed with various plane size and various thickness of specimens in two materials. The test results showed that the effects of plane size in th4 J-R curve were significant and the curve was risen with an increase in plane size. However, relatively weak influence was observed form the change of the specimen thickness and size. The stress fields near the crack tip of th specimen is close to the HRR field according to increasing the plane size and Q stress appears different value according to material properties and the plane size.

Output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser (반도체레이저 단면여기 Nd:S-VAP 레이저의 내부공진기 제2고조파 출력 특성)

  • 박준학
    • Korean Journal of Optics and Photonics
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    • v.11 no.4
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    • pp.294-298
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    • 2000
  • The output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser were investigated. Nd:S-VAP is suitable for a microchip laser medium, which has a low threshold property because of a very high value of the stimulated emission cross-section and lifetime product. The threshold energy measured was 81 J.ll. The second harmonic output energy measured was $126\mu\textrm{J}$at a pump energy of $2\mu\textrm{J}$. We described for intracavity frequency doubling by using theoretical calculations. Q-switched second harmonic energy measured was $15\mu\textrm{J}$per pulse with a pulse-width of 26 ns. at a pump energy of 2 mJ and an $M^2$ of 1.47 represented a good beam quality. ality.

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On the historical investigation of Bernoulli and Euler numbers associated with Riemann zeta functions (수학사적 관점에서 오일러 및 베르누이 수와 리만 제타함수에 관한 탐구)

  • Kim, Tae-Kyun;Jang, Lee-Chae
    • Journal for History of Mathematics
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    • v.20 no.4
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    • pp.71-84
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    • 2007
  • J. Bernoulli first discovered the method which one can produce those formulae for the sum $S_n(k)=\sum_{{\iota}=1}^n\;{\iota}^k$ for any natural numbers k. After then, there has been increasing interest in Bernoulli and Euler numbers associated with Riemann zeta functions. Recently, Kim have been studied extended q-Bernoulli numbers and q-Euler numbers associated with p-adic q-integral on $\mathbb{Z}_p$, and sums of powers of consecutive q-integers, etc. In this paper, we investigate for the historical background and evolution process of the sums of powers of consecutive q-integers and discuss for Euler zeta functions subjects which are studying related to these areas in the recent.

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Detection of Copy Number Variation of the KIT Gene in the Landrace Breed using an Quantitative Oligonucleotide Ligation Assay(qOLA) (Quantitative Oligonucleotide Ligation Assay(qOLA)를 이용한 Landrace 품종의 KIT 유전자 반복수 변이 탐지)

  • Seo, B.Y.;Kim, J.H.;Nahm, D.W.;Yoo, C.K.;Lee, S.H.;Lee, J.B.;Lim, H.T.;Jung, E.J.;Cho, I.C.;Heo, K.N.;Jeon, J.T.
    • Journal of Animal Science and Technology
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    • v.49 no.5
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    • pp.559-568
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    • 2007
  • Recently, copy number variations (CNV) of genes or genomic segments have been intensively studied and various analysis methods have been developed. In this study, quantitative oligonucleotide ligation assay (qOLA) was applied to investigate CNV of KIT gene in the Landrace breed. A combined assay using qOLA and pyrosequencing, 6 genotype classes, I1/I1 or I3/i (IBe), I1/I2 or I3/IP, I1/I3, I1/IP or I2/i (IBe), I2/I2and I2/IP, were identified from 44 Landrace pigs. Genotype assignment using grouping features of measurements on a scatter plot showed 100% agreement with those using a statistical assignment by PROC FASTCLUS procedure implemented in the SAS package. Two versions (3100 and 3130) of ABI sequencers gave the same genotyping results, indicating there was no influence on qOLA by different versions of instrument, however, the means of standard deviation and coefficient of variation from the qOLA on a ABI 3130 (2.33 and 4.10) was lower than those from the qOLA on a ABI 3100 (2.67 and 4.81). Effect of proteinase K treatment on the PCR product followed by qOLA was very clear because noise peaks were disappeared and the observed ration fit better to the reference ratio corresponding to each genotype.

Design of Disturbance Observer Considering Robustness and Control Performance (1) : Analysis on Second Order System (강인성과 제어 성능을 고려한 외란 관측기의 설계 (1) : 2차 시스템에 대한 이론적 해석)

  • Park, Youngjin;Yang, Gwang-Jin;Chunng, Wan-Kyun;Kim, Hong-Rok;Suh, Il-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.8
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    • pp.655-664
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    • 2002
  • The disturbance observer (DOB) has been widely utilized for high precision/speed motion control applications. However, it still lacks the analysis for the robustness and performance brought by using DOB. This paper proposes the robustness measure of DOB and reveals the relationships between the disturbance rejection performance and the order/time constant of a Q filter in DOB. Additionally, we propose six guidelines for the design of Q filter and show their validity through the experiments for DVD systems.

The characteristics of the passively Q-switched Nd:YAG laser output energy with the initial absorbing effect of Cr4+:YAG absorber (수동 큐스위칭 Nd:YAG 레이저에서 포화흡수체 Cr4+:YAG의 초기 광흡수 효과와 출력 특성)

  • Choi, Young-Soo;Yoon, Joo-Hong;Kim, Ki-Hong
    • Korean Journal of Optics and Photonics
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    • v.13 no.4
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    • pp.340-346
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    • 2002
  • To understand the characteristics of the passively Q-switched Nd:YAG laser output energy with $Cr^{4+}$:YAG saturable absorbers, the transmissions of $Cr^{4+}$:YAG and the inversion population densities of Nd:YAG at the onset of Q-switch were experimentally analysed. The measured transmissions at the onset of Q-switch were 0.70$\pm$0.02 and 0.62$\pm$0.02 for the 0.48 and 0.38 of initial transmission, respectively. It means that the initial transmission loss of $Cr^{4+}$:YAG absorber is reduced in a low Q-state due to the initial absorbing effect of $Cr^{4+}$:YAG. In pumping stage, $Cr^{4+}$:YAG has absorbing processes due to the fluorescence and amplified spontaneous emissions of the Nd:YAG even if there is no laser oscillation. The minimum population inversion densities for Qswitch were approximately 3.7${\times}{10^{17}}$ and 4.0${\times}{10^{17}}$ $cm^{-3}$, respectively. At the beginning of Q-switch, the number density of $Cr^{4+}$ions in the ground state of $Cr^{4+}$:YAG was approximately 1.4${\times}{10^{17}}$ $cm^{-3}$ and the ratio of the ground to the excited state of absorbing $Cr^{4+}$ions was 0.44 both. The modified theoretical output energies with the initial absorbing effect were 18 and 18.5 mJ. The measured output energies were 17$\pm$1 and 18$\pm$1.5 mJ, respectively. The quantum extraction efficiencies of Q-switch were 0.32 both. The theoretical Q-switched output results with the initial absorbing effect of the saturable absorber are a good agreement with the experimental results.

Cognition for First Aid in Persons Taking First Aid Education Theory and Practice related to Convergence Training (응급처치 이론 및 실습 융합교육을 받은 대상자들의 응급처치에 대한 인식)

  • Kim, Yun-Jeong
    • Journal of the Korea Convergence Society
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    • v.6 no.3
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    • pp.1-12
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    • 2015
  • The purpose of this study is to examine the structure of subjective cognition for first aid in persons taking first aid eduction. The perception of first aid styles were classified by using the PC QUANL program. Data were collected from March to July, 2010. As a result of the study, the cognition for first aid in persons taking first aid eduction can be classified into these four types: 'Time-oriented type', 'First responder-oriented type', 'Convergence education-oriented type', 'Lay person using-oriented type'. Therefore, in the field of first aid practice and education this study has provided practical guidelines helpful to nursing intervention and family-centered nursing by considering each character of the types centering on the relationship of lay person, and will be useful as basic data for relevant disciplines in education.