• 한방재활의학과학회지
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• 제32권1호
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• pp.51-62
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• 2022

Objectives Objective of this study is to investigate the role of paraspinal muscles by examining the correlation between slip percentage (SP) of spondylolisthesis and fatty infiltration of lumbar paraspinal muscle. Methods Retrospective analysis was performed on 45 patients diagnosed with spondylolisthesis based on medical records. Using T2-weighted axial magnetic resonance imaging, cross-sectional areas (CSAs) of psoas major (PM), multifidus (MU) and erector spinae (ES) were calculated and divided by CSA of lower level vertebral body (VB). SP was measured using sagittal T2-weighted images. Correlation of SP with muscle relative cross-sectional area (RCSA) and muscle fatty infiltration by Goutallier classification was respectively analyzed using Spearman correlation. Statistic assessment conducted by Wilcoxon signed rank test and paired t-test using program GraphPad prism 5 (GraphPad Software, Inc., San Diego, CA, USA). Results Spondylolisthesis forward slip percentage by Taillard's method was negatively associated with both side MU RCSAs. No significant correlation was found between PM RCSA, ES RCSA and SP. Forward slippage was significantly correlated with fatty infiltration of lumbar paraspinal muscle measured by Goutallier classification. Conclusions This study is to understand the role of paraspinal muscle affecting spinal instability by investigating correlation between statistical deviation of lumbar muscle characters (RCSA, fatty infiltration of lumbar muscle) and SP. We found that spondylolisthesis SP is positively related to fatty infiltration of lumbar paraspinal muscle. and is negatively associated with both side MU RCSAs.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2006년도 추계학술발표대회 및 제11회 신소재 심포지엄
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• pp.31.2-31.2
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• 2006

• 한국구조물진단유지관리공학회 논문집
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• 제9권1호
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• pp.233-241
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• 2005

본 연구는 콘크리트로 충전한 절곡된 단면을 갖는 각형강관 기둥의 부착특성을 매입인발(Pull-out) 시험을 통해 평가하였다. 시험체는 단면 $250{\times}250mm$의 강관 단면에 콘크리트를 충진한 PSSC기둥으로 표준형(P), 사다리꼴(I), 직사각형(II), 역사다리꼴(III)의 4가지 형태(Fig. 3)와, 부착길이에 대한 폭비 (L/D=2.0, 2.5, 3.0) 단면의 폭두깨비(d/t)으로 설정하여 총 13로 하였다. 실험결과 얇은 판요소 절곡된 강관과 콘크리트의 부착거동은 일반적인 부착거동과 유사하게 화학적 부착과 기계적 부착의 형태로 거동하였으며, 부착응력은 강판의 절곡형태가 (equation omitted)순으로 높게 나타났다. 또한 (equation omitted)타입 시험체의 경우에는 얇은 판요소를 갖는 단면임에도 불구하고 AIJ에서 제시하고 있는 $0.147N/mm^2$의 값을 상회하는 것으로 나타나 부착응력을 고려할 수 있을 것으로 판단되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.765-770
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• 2000

Hot-wire measurements are reported on the developing turbulent flows subject to plane rate of strain in a rotating $90^{\circ}$ dog bend. The cross-section of the bend varies from $100mm{\times}50mm$ rectangular shape at the bend inlet gradually to the $50mm{\times}100mm$ shape at the bend outlet with remaining a constant area. Data signals from the rotating test section are transmitted through a slip ring to the personal computer which is located at the outside of the rotating disc. 3-dimensional velocity and 6 Reynolds stress components were calculated from the equations which correlate the fluctuating and mean voltage values measured with rotating a slant type hot-wire into 6 orientations. The effects of Coriolis and centrifugal forces on the mean motions and turbulence structures are investigated with respect to rotational speed.

• 대한관절경학회지
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• 제7권1호
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• pp.92-95
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• 2003

34세 남자 환자로 등산중 실족으로 발생한 전방십자인대의 완전파열로 자가 슬괵건을 이용한 경핀 고정법으로 전방십자인대 재건술을 시행하였다. 술후 경과는 양호하였으나 술후 3개월째 굴신 신전 운동 시 슬부 후측면의 동통과 지속적인 관절내 부종 소견을 보였으며 수차례의 관절천자와 약물투여에도 반응이 없었다. 컴퓨터 단층 촬영 상후방 피질 골의 천공이 관찰되어 술후 6개월째 이차관절내시경 수술을 시행하였다. 내시경 소견상 경핀고정물의 전방부 1/3에 일치되는 투명한 이물질과 대퇴경골관절면의 연골의 손상이 관찰되었으며 이물 제거 후 증세는 호전되었다. 경핀 터널의 잘못된 위치가 실패의 원인이라고 생각되었으며 경핀고정법을 이용한 전방십자인대 재건술시, 슬관절 과굴곡 상태에서 예각의 대퇴 터널을 만들어 후방 피질 골을 두껍게 남기고, 핀 홀을 만들 때 경핀가이드를 횡상과축보다 $10\~20$도 외회전시켜야 대퇴골 후방피질골의 천공을 방지할 수 있어 조기 실패를 예방할 수 있다고 생각된다.

• 한국강구조학회 논문집
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• 제12권6호
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• pp.671-680
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• 2000

이 논문은 합성슬래브의 구조적 거동에 관한 것으로, 개방형 형상인 사다리꼴 데크플레이트와 폐쇄형인 역삼각형 상단플랜지 데크플레이트를 사용한 합성슬래브의 실험에 의한 것이다. 그 결과 합성슬래브의 합성거동을 위해서는 데크플레이트의 형상적인 요소가 매우 중요한 변수로 나타났다. 즉 폐쇄형 형상인 역삼각형 데크플레이트가 사다리꼴 형상보다 전단슬립과 처짐에 더 효과적으로 나타났다. 그러므로 합성데크슬래브 용도로 사용되는 데크플레이트의 개발과 사용에 있어 형상적인 요소가 매우 중요하게 취급되어야 하며, 이에 대한 이론적인 평가도 이루어 졌다.

• 한국안전학회지
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• 제26권2호
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• pp.62-69
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• 2011

This paper presents a new simple two-dimensional frame finite element able to accurately estimate the load-carrying capacity of reinforced concrete beams flexurally strengthened externally bonded fiber reinforced polymer (FRP) strips and plates. The proposed analysis model considers distributed plasticity with layer-discretization of the cross-sections and the bond-slip behavior of epoxy layer. The proposed model is used to predict the load-carrying capacity and the applied load-midspan deflection response of RC beams subjected to bending loading. Numerical simulations and experimental measurements are compared based on numerous tests available in the literature and published by different authors. The numerically simulated response agree remarkably well with the corresponding experimental results. Thus, the proposed model is suitable for efficient and accurate modeling and analysis of flexural strengthening of RC beams with externally bonded FRP sheets/plates and for practical use in design-oriented parametric studies.

• Geomechanics and Engineering
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• 제23권4호
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• pp.351-364
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• 2020

This paper numerically investigates the effects of a dip-slip fault (a normal or a reverse fault) movement on a segmental tunnel which transversely crosses either of this kind of faults. After calibration of the numerical model with results from literature of centrifuge physical tests, a parametric study is conducted to evaluate the effects of various parameters such as the granular soil properties, the fault dip angle, the segments thickness, and their connections stiffnesses on the tunnel performance. The results are presented and discussed in terms of the ground surface and tunnel displacements along the longitudinal axis for each case of faulting. The gradient of displacements and deformations of the tunnel cross section are also analyzed. It is shown that when the fault dip angle becomes greater, the tunnel and ground surface displacements are smaller, in the case of reverse faulting. For this type of fault offset, increasing the tunnel buried depth causes tunnel displacements as well as ground surface settlements to enhance which should be considered in the design.

• 한국산업보건학회지
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• 제26권3호
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• pp.253-266
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• 2016

Objectives: This study is for characteristics of asbestos occurrence (NOA, naturally occurring asbestos) from the Gapyeong area and its host rocks, serpentinites. Methods: Representative samples are collected from the serpentinite bodies, following degrees of hydrothermal alteration and metamorphism, after about 2 year field trips. Mineralogical, morphological and optical characteristics of the asbestos and host rocks are confirmed by PLM, XRD EPMA and SEM results. Results: The serpentinites are dunites and harzburgites, and host asbestos, including chrysotile, tremolite and actinolite. The asbestos chrysotiles are found as veins ranging from several millimeters to several centimeters in thickness, while asbestos-tremolite and -actinolite occur along cracks and fractures ranging up to ten centimeters in thickness. The chryostiles occur mainly as cross and slip fibers, while the amphibole asbestos is found as vein, slip and oblique fibers. More tremolitic grains are colorless and commonly show elongated or fiber shapes, whereas the magnesio hornblende grains mainly show light green and occur as subhedral to euhedral diamond grains. Conclusions: Overall characteristics of serpentinites from the Gapyeong area are similar to worldwide orogenic-related Alpine type ultramafic rocks serpentinized and serpentinites in South Chungcheong-do Province, Korea, and occurrences of asbestos are similar to those of the ultramafic bodies in South Chungcheong-do Province.

• Structural Engineering and Mechanics
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• 제39권5호
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• pp.717-732
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• 2011

Nonlinear dynamic analysis and evaluation of eccentric braced steel frames (EBF) equipped with friction damper (FD) is studied in this research. Previous studies about assessment of seismic performance of steel braced frame with FD have been generally limited to installing this device in confluence of cross in concentrically braced frame such chevron and x-bracing. Investigation is carried out with three types of steel frames namely 5, 10 and 15 storeys, representing the short, medium and high structures respectively in series of nonlinear dynamic analysis and 10 slip force values subjected to three different earthquake records. The proper place of FD, rather than providing them at all level is also studied in 15 storey frame. Four dimensionless indices namely roof displacement, base shear, dissipated energy and relative performance index (RPI) are determined in about 100 nonlinear dynamic analyses. Then average values of maximum roof displacement, base shear, energy dissipated and storey drift under three records for both EBF and EBF equipped with friction damper are obtained. The result indicates that FD reduces the response compared to EBF and is more efficient than EBF for taller storey frames.