• 한국강구조학회 논문집
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• 제17권5호통권78호
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• pp.519-526
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• 2005

혹서기에 레일의 높은 온도 상승(최대 $60^{\circ}C$)으로 인해 장대레일 궤도에는 매우 큰 압축력이 작용하게 된다. 이러한 압축력은 장대레일 궤도의 좌굴을 발생시키기도 한다. 본 연구에서는 장대레일 궤도의 좌굴에 영향을 미치는 많은 요소들 중에서 도상 횡저항력 그리고 도상 종저항력이 궤도 좌굴에 미치는 영향을 파악하기 위한 연구를 수행하였다. 또한 줄틀림과 궤간틀림의 민감도를 분석하였다.

• Corrosion Science and Technology
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• 제4권3호
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• pp.108-113
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• 2005

One of the recent safety issues in the pressurized heavy water reactor (PHWR) is the cracking of the feeder pipe. Because of the limited accessibility to the cracked region and a high dose of radiation exposure, it is difficult to inspect all the pipes with the conventional ultrasonic method. In order to solve this problem, a long-range guided wave technique has been developed. A computer program to calculate the dispersion curves in the pipe was developed and the dispersion curves for the feeder pipes in PHWR plants were determined. Several longitudinal and/or flexural modes were selected from the review of the dispersion curves and an actual experiment has been carried out with the specific alignment of the piezoelectric ultrasonic transducers. They were confirmed as L(0,1)) and/or flexural modes(F(m,2)) by the short time Fourier transformation(STFT) and were sensitive to the circumferential cracks, but not to the axial cracks in the pipe. An electromagnetic acoustic transducers(EMAT) was designed and fabricated for the generation and reception of the torsional guided wave. The axial cracks were detected by a torsional mode(T(0,1)) generated by the EMAT.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.125-128
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• 2005

The dispersion of carbon nanofiber (CNF) was carried out by solution blending, mechanical mixing, and sonication. CNFs at levels of 5-50% fiber weight content were mixed with polypropylene (PP) powder, and then were melt-mixed using a twin-screw extruder. For the further alignment of fibers, extruded rods were stacked uni-directionally in the mold cavity for the compression molding. For the evaluation of mechanical properties of nanocomposites, tension, in-plane shear, and flexural tests were conducted. CNF/PP composites clearly showed reinforcing effect in the longitudinal direction. The tensile modulus and strength have improved by 100% and 40%, respectively for 50 % fiber weight content, and the flexural modulus and strength have increased by 120% and 25%, respectively for the same fiber weight content. The shear modulus showed 65% increase, but the strength dropped sharply by 40%. However, the property enhancement was not significant due to the poor adhesion between fiber and matrix. In the transverse direction, the tensile, flexural, and shear strength decreased as more fibers were added.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.532-538
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• 2000

A double rectangular spiral inductor is fabricated using FeTaN films. The inductor is composed of internal coils sandwiched by magnetic layers. Characteristics of inductor performance are investigated with an emphasis on planarization of magnetic films. In the absence of the planarization process, the grating topology of upper magnetic films over coil arrays degrades the soft magnetic properties and the inductor performance. It also induces a longitudinal magnetic anisotropy with the easy axis aligned to the magnetic flux direction. This alignment prevents the upper magnetic films from contributing to the total induction. Glass bonding is a viable method for achieving a completely planar inductor structure. The planar inductor with glass bonding shows excellent performance : inductance of 1.1 H, Q factor of 7 (at 5 MHz), and the dc current capability up to 100 mA.

• 한국환경복원기술학회지
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• 제13권6호
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• pp.133-144
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• 2010

The objective of this planning proposal is to rehabilitate the urban stream which has been ecologically disturbed in the urban process. The experimental stream, Su-am stream located in Anyang City is typical urban stream in adjacent land use and the spatial condition. The stream in the watershed context, is the second tributary of Han River, in the Anyangcheon watershed. The Characteristics of the stream reach were analyzed by the river corridor survey. In the conceptual phase, Rehabilitation Programs were established based on the hydrological, ecological and spatial characteristics of the stream. Spatial zoning concept according to the characteristics of the stream and adjacent land use, was suggested 4 types of zoning; ecological preservation zone, natural landscape zone, neighborhood water-friendly zone and CBD water-friendly zone. Implementation Practices can be summarized as follow: For The longitudinal river continuum, some In-stream practices were suggested and implemented; such as channel alignment, step & pool, pool & riffle and low-flow channel bank. For latitudinal continuum and intimate spatial relationship between Sam-duk Park & Su-am stream, gentle sloped bank was planned and implemented. After stream improvement & ecological Implementation, follow-up monitoring and adaptive management programs will be a meaningful process for ecological rehabilitation.

• 국제물리치료학회지
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• 제10권4호
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• pp.1934-1939
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• 2019

Background: Flexible flat foot is that the medial longitudinal arch collapses in weight bearing and returns normal arch when weight is removed and the weight bearing shifts toward medial part of the foot, which can cause pathological problems in the alignment of the lower extremities and the entire body. Objective: To compare the foot pressure for adults with flexible flat foot. Design: Quasi-Experimental Study Methods: 24 participants with flexible flat foot were recruited and were randomly divided into Visual feedback Short Foot Exercise (VSFE) group and Short Foot Exercise (SFE) group. To compare changes of foot pressure about pre and post intervention, the contact pressure measurement was conducted. Results: In the VSFE, significant differences were observed for the foot pressure of the 1^st toe, 1^st, 3^rd and 4-5^th metatarsal, midfoot, medial and lateral heel (p<.05). The foot pressure of the 3^rd and 4-5^th metatarsal, midfoot showed significant differences in the SFE (p<.05). The contact pressure of the 1^st toe, 3^rd metatarsal showed significant differences between the groups. Conclusions: Visual feedback short foot exercise can be useful for moving the pressure from medial to lateral part, and can prevent possible pathological problems.

• 문화기술의 융합
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• 제6권4호
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• pp.669-675
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• 2020

본 연구에서는 인접굴착공사 시 지하철 궤도에 발생되는 변형수준을 평가하는데 있어서 3D 해석 모델로 분석하였으며, 해석의 주요 매개변수로서 터널모델의 경계조건과 지하수위 적용 수준 설정하여 해석을 수행하였다. 3차원 수치해석 모델을 이용한 궤도틀림 영향 검토 결과, 3차원 모델의 시종점부 경계조건의 구속조건을 변경하고, 설계지 하수위가 아닌 현장지하수위를 고려한 해석모델의 경우 보다 합리적인 궤도변형 예측이 가능한 것으로 분석되었다. 또한 해석모델의 경계조건 및 하중조건에 따른 궤도틀림의 영향은 방향틀림, 고저틀림 및 궤간틀림과 같이 레일의 종방향 상대변위 발생에 직접적인 영향을 받는 인자에서 보다 명확한 차이가 발생되었다. 따라서 열차진행방향에 대한 선로의 변형유무를 평가하기 위한 인접굴착공사에 따른 궤도안정성 평가 시에는 레일의 변형수준을 평가할 수 있는 3차원 수치모델을 사용하여 궤도의 변형을 평가하는 것이 적정한 것으로 분석되었다. 또한 수치모델의 시종점부 경계조건 및 하중조건 설정에 주의가 필요한 것으로 분석되었다.

• 한국도로학회논문집
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• 제10권2호
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• pp.125-133
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• 2008

차량의 주행속도는 설계일관성을 평가하는 주요한 척도로 활용되며 그 중 곡선반경은 여러 연구에서 공통적으로 제시한 주된 요인으로 나타났다. 이에 본 연구에서는 복합선형에서 설계속도별 적정 평면곡선반경 범위기준을 정립하고 운전자의 인지 행태를 나타낼 수 있는 인지반경을 정립하여 입체선형에서 적합한 평면곡선반경을 제시하고자 한다. 첫째, 본 연구에서는 저속차량의 방해요소를 최소화하기 위하여 입체선형을 고려한 도로의 임의지점에서 횡방향 미끄럼 마찰계수와 주행방향 미끄럼 마찰계수를 동시에 고려하여 설계속도와 종단경사별 평면곡선반경을 제시하였다. 둘째, 본 연구에서는 곡선부 인지반경을 통하여 평면 곡선부와 편평한 종단경사가 조합된 경우, 평면 곡선부와 종단곡선부가 조합된 경우를 비교한 후, 곡선부 인지반경을 산정하여 설계속도별 적정 평면곡선반경과 인지반경 비율을 제시하였다.

• Journal of Trauma and Injury
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• 제23권2호
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• pp.175-179
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• 2010

Purpose: Sternal fractures after blunt thoracic trauma can cause significant pain and disability. They are relatively uncommon as a result of direct trauma to the sternum and open reduction is reserved for those with debilitating pain and fracture displacement. We reviewed consecutive 11 cases of open reduction and fixation of sternum and tried to find standard approach to the traumatic sternal fractures with severe displacement. Methods: From December 2008 to August 2010, the medical records of 11 patients who underwent surgical reduction and fixation of sternum for sternal fractures with severe displacement were reviewed. We investigated patients' characteristics, chest trauma, associated other injuries, type of open reduction and fixation, combined operations, preoerative ventilator support and postoperative complications. Results: The mean patient age was 59.3years (range, 41~79). The group comprised 6 male and 5 female subjects. Among 11 patients who underwent open reduction and fixation for sternal fracture with severe displacement, 6 cases had isolated sternal fractures and the other 5 patients had associated other injuries. Sternal fractures were caused by car accidents (9/11, 81.8%), falling down (1/11, 9.1%) and direct blunt trauma to the sternum (1/11, 9.1%), respectively. 3 of the 7 patients (42.9%) who underwent sternal plating with longitudinal plates showed loosening of fixation. Otherwise, none of the 4 patients who underwent surgical fixation using T-shaped plate had stable alignment of the fracture. Conclusion: Sternal fractures with severe displacement need to be repaired to prevent chronic pain, instability of the anterior chest wall, deformity of the sternum, and even kyphosis. In the present study, a T-shaped plate with a compression-tension mechanism constitutes the treatment of choice for displaced sternal fractures.

• 비파괴검사학회지
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• 제34권1호
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• pp.23-30
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• 2014

$SiC_f$/SiC 복합재를 제작하여, $SiC_f$/SiC 복합재의 섬유배향 방향에 따르는 마모 특성을 평가하고, 마모시에 발생하는 탄성파를 검출하고 분석하였다. $SiC_f$/SiC 복합재는 섬유의 종 횡방향에 의한 마찰계수와 마모손실은 비슷하였으나, 섬유의 수직방향은 가장 작은 값을 나타내었다. 이것은 섬유의 취성 특성 때문이라 판단되며, 마모손실과 마찰계수는 정비례의 관계를 나타내었다. SiC 단상재의 탁월주파수는 58.6 kHz를 나타내고, $SiC_f$/SiC 복합재의 탁월주파수는 117.2와 136.7 kHz였다.