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초음파법을 이용한 콘크리트 역타시공 이음부 공극의 화상검출특성
박석균,백운찬,이한범,김명모 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.4
최근 역타시공법 등에 의한 콘크리트 구조물의 시공이 증가 추세에 있다. 이 경우, 자주 발생되는 신ㆍ구타설 콘크리트 시공이음부의 공극은 향후 구조물의 구조적인 특성과 내구성 등에 큰 영향을 미치게 된다. 그러나 현재 제안되고 있는 비파괴 검사법으로는 효과적으로 이음부 공극을 평가하기에 많은 한계가 있다. 본 연구에서는 시공이음부의 콘크리트 충전상태를 평가하기 위해 철골철근 콘크리트와 무근 콘크리트 시험체내에 공극을 모의제작한 후, 초음파속도 측정을 실시하고, 화상처리기법을 이용하여 비교적 용이하게 해석 가능한 방법에 대해 검토하였다.
초음파법을 이용한 콘크리트 시공이음부 공극 및 내부공동의 화상검출 해석에 관한 연구
박석균,백운찬,이한범 대전대학교 산업기술연구소 2000 산업기술연구소 論文集 Vol.11 No.2
The joint and void treatment of concrete is one of the technical problems in construction. Joints and voids created with the construction result in serious weakness from the aspects of both structural and water-barrier function. Ultrasonic image processing technique was used for the inspection of construction joints of SRC(Steel-frame Reinforced Concrete) column and voids of concrete block in this study. The advantages and limitations of this technique for non-destructive inspection in construction joints and voids are investigated. As a result, it has been verified that the semi-direct measurement type is more effective than the other types for detecting the construction joints and voids using ultrasonic method.
A High-Linearity Low-Noise Reconfiguration-Based Programmable Gain Amplifier
Seok-Kyun Han,Hyu-Hieu Nguyen,Sang-Gug Lee 대한전자공학회 2013 Journal of semiconductor technology and science Vol.13 No.4
This paper presents a high-linearity low-noise small-size programmable gain amplifier (PGA) based on a new low-noise low-distortion differential amplifier and a proposed reconfiguration technique. The proposed differential amplifier combines an inverter-based differential pair with an adaptive biasing circuit to reduce noise and distortion. The reconfiguration technique saves the chip size by half by utilizing the same differential pair for the input transconductance and load-stage, interchangeably. Fabricated in 0.18- ㎛ CMOS, the proposed PGA shows a dB-linear control range of 21dB in 16 steps from-11dB to 10 dB with a gain error of less than ±0.33 dB, an IIP3 of 7.4~14.5 dBm, a P1dB of -7~1.2 dBm, a noise figure of 13dB, and a 3-dB bandwidth of 270㎒ at the maximum gain, respectively. The PGA occupies a chip area of 0.04㎟ and consumes only 1.3㎃ from the 1.8V supply.
A High-Linearity Low-Noise Reconfiguration-Based Programmable Gain Amplifier
Han, Seok-Kyun,Nguyen, Huy-Hieu,Lee, Sang-Gug The Institute of Electronics and Information Engin 2013 Journal of semiconductor technology and science Vol.13 No.4
This paper presents a high-linearity low-noise small-size programmable gain amplifier (PGA) based on a new low-noise low-distortion differential amplifier and a proposed reconfiguration technique. The proposed differential amplifier combines an inverter-based differential pair with an adaptive biasing circuit to reduce noise and distortion. The reconfiguration technique saves the chip size by half by utilizing the same differential pair for the input transconductance and load-stage, interchangeably. Fabricated in $0.18-{\mu}m$ CMOS, the proposed PGA shows a dB-linear control range of 21dB in 16 steps from -11 dB to 10 dB with a gain error of less than ${\pm}0.33$ dB, an IIP3 of 7.4~14.5 dBm, a P1dB of -7~1.2 dBm, a noise figure of 13dB, and a 3-dB bandwidth of 270MHz at the maximum gain, respectively. The PGA occupies a chip area of $0.04mm^2$ and consumes only 1.3 mA from the 1.8 V supply.
Preparation of Recycled Polyvinyl Alcohol) (PVA)/Iodine Polarizing Film
Han, Man Ho,Shin, Jae Kyun,Oh, Kyeong Il,Lee, Young Jae,Song, Du Hyun,Chung, Yong Sik,Lee, Yong Rok,Choi, Han Gon,Oh, Tae Hwan,Han, Sung Soo,Noh, Seok Kyun,Lyoo, Won Seok SAGE Publications 2010 POLYMERS AND POLYMER COMPOSITES Vol.18 No.7
The association between migraine and Parkinson’s disease: a nationwide cohort study in Korea
Woo-Seok Ha(Woo-Seok Ha),Jaeho Kim(Jaeho Kim),Hee Won Hwang(Hee Won Hwang),Sue Hyun Lee(Sue Hyun Lee),Ji In Kim(Ji In Kim),Jin Yong Hong(Jin Yong Hong),Sang Hyun Park(Sang Hyun Park),Kyung Do Han(Kyun 한국역학회 2024 Epidemiology and Health Vol.46 No.-
약학박사 정 시련 교수 정년퇴임 기념호 : 연구논문(재록) ; 생명과학 : 동결-해동에 의해 제조된 신디오탁틱폴플리비닐알코올 하이드로젤에서 소 혈청 알부민의 유리 특성
류원석 ( Won Seok Lyoo ),신동수 ( Dong Soo Shin ),한성수 ( Sung Soo Han ),노석균 ( Seok Kyun Noh ),김정애 ( Jung Ae Kim ),최한곤 ( Han Gon Choi ),용철순 ( Chul Soon Yong ),김재룡 ( Jae Ryong Kim ),김정희 ( Jung Hye Kim ) 영남대학교 약품개발연구소 2006 영남대학교 약품개발연구소 연구업적집 Vol.16 No.-
Lyoo, Won Seok,Yeum, Jeong Hyun,Kwon, Oh Wook,Shin, Dong Soo,Han, Sung Soo,Kim, Byoung Chul,Jeon, Han Yong,Noh, Seok Kyun Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of applied polymer science Vol.102 No.4
<P>To identify the effect of blend ratios of syndiotacticity-rich poly(vinyl alcohol) (s-PVA)/atactic PVA (a-PVA) having similar number-average degrees of polymerization (P<SUB>n</SUB>)s of 4000 and degrees of saponification (DS)s of 99.9% on the rheological properties of s-PVA/a-PVA/water solutions, water-soluble s-PVA and a-PVA with different syndiotactic diad contents of 58.5 and 54.0%, respectively, were prepared by bulk copolymerization of vinyl pivalate and vinyl acetate (VAc) and solution polymerization of VAc, followed by saponifying the corresponding copoly(vinyl pivalate/vinyl acetate) and poly(vinyl acetate). The blend ratios played a significant role in rheological behavior. Over the frequency range of 10<SUP>−1</SUP>–10<SUP>2</SUP> rad/s, s-PVA/a-PVA blend solutions with larger s-PVA content show more shear thinning at similar (P<SUB>n</SUB>)s and (DS)s of polymer, suggesting that PVA molecules are more readily oriented as s-PVA content increases. Yield stress is higher for s-PVA/a-PVA blend solutions with larger s-PVA content at similar (P<SUB>n</SUB>)s and (DS)s of polymer. This indicates that more domains with internal order are produced at larger s-PVA content in s-PVA/a-PVA blend solutions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3934–3939, 2006</P>
Lim, Hyun Ju,Lee, Sung Jun,Bae, Han Jo,Noh, Seok Kyun,Lee, Yong Rok,Han, Sung Soo,Jeon, Han Yong,Park, Won Ho,Lyoo, Won Seok Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of applied polymer science Vol.106 No.5
<P><B>Abstract</B></P><P>The effects of tacticities on the characteristics of poly(vinyl alcohol) (PVA) nanowebs prepared by an electrospinning technique were investigated. PVA webs composed of uniform nanofibers with syndiotactic dyad (s‐dyad) contents of 53.5 and 57.3% were successfully obtained with electrospinning. By changing processing parameters such as the initial polymer concentration, applied voltage, and tip‐to‐collector distance, we found suitable conditions for forming PVA webs with uniform nanofibers. PVAs of higher s‐dyad contents were prepared at a lower solution concentration and at a higher applied voltage because of the easy formation of syndiotactic PVA chain entanglements at a very low polymer concentration. The average diameter of the nanofibers in a PVA web with the higher s‐dyad content of 57.3% (ca. 240 nm) was thinner than that of the nanofibers in a PVA web with the lowers‐dyad content of 53.5% (ca. 270 nm). In addition, the crystallinity and thermal stability were greatly increased with an increase in the s‐dyad content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007</P>
Surface free energy analysis of poly(vinyl alcohol) films having various molecular parameters
Kim, Joon Ho,Shin, Dong Soo,Han, Man Ho,Kwon, Oh Wook,Lee, Hyun Kyu,Lee, Se Geun,Ghim, Han Do,Park, Joo Min,Han, Sung Soo,Noh, Seok Kyun,Lyoo, Won Seok Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of applied polymer science Vol.105 No.2
<P>The molecular parameters of poly(vinyl alcohol) have enormous effects on its physical and chemical properties. Therefore, the surface characteristics of poly(vinyl alcohol) films are also determined by the molecular parameters. In this study, the dependence of the surface free energy on the molecular weight, degree of saponification, and stereoregularity of poly(vinyl alcohol) films has been evaluated with contact-angle measurements. The surface free energy of poly(vinyl alcohol) films increases with decreases in the syndiotactic dyad content, molecular weight, and degree of saponification. The polar component of the surface energy is not affected by the deviation of the molecular weight and degree of saponification very much. However, it decreases with increases in the syndiotactic dyad content and ranges from 11.64 to 4.35 dyn/cm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007</P>