• 전자공학회논문지
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• 제51권8호
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• pp.30-37
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• 2014

본 논문에서는 실제 공정을 반영한 FinFET의 게이트 저항 압축모델을 개발하였다. 삼차원 소자 시뮬레이터 Sentaurus를 사용하여, Y-parameter 해석 방법을 적용하여 게이트 저항을 추출하여 제안하는 모델을 검증하였다. FinFET 게이트의 전기장이 수평 수직 방향으로 형성됨을 고려하여 모델링함으로써, FinFET 게이트 저항의 비선형성을 반영하였다. 현재 제작되고 있는 FinFET에서 게이트가 두 물질(Tungsten, TiN)로 적층된 구조일 수 있음을 고려하여, 비저항이 서로 다른 물질을 적층 시킨 구조에 대한 압축 모델을 개발하였다. 제안하는 모델을 사용하여, 게이트의 기하학적 구조 변수 변화에 따른 게이트 저항이 최소가 되는 fin의 수를 제안하였다. BSIM-CMG에 제안하는 모델을 구현한 후, ring-oscillator를 설계하고, 게이트 저항이 고려되지 않았을 때와 고려되었을 때의 각단의 신호지연을 회로 시뮬레이터를 통해 비교하였다.

• Steel and Composite Structures
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• 제21권5호
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• pp.1157-1182
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• 2016

A newly puzzle shape of crestbond rib shear connector is a type of ductile perfobond rib shear connector. This shear connector has some advantages, including relatively easy rebar installation and cutting, as well as the higher shear resistance strength. Thus, this study proposed a newly puzzle shape of crestbond rib with a "${\mho}$" shape, and its shear resistance behaviors and shear strengths were examined using push-out tests. Five main parameters were considered in the push-out specimens to evaluate the effects of shear resistance parameters such as the dimensions of the crestbond rib, transverse rebars in the crestbond dowel, concrete strength, rebar strength, and dowel action on the shear strength. The shear loading test results were used to compare the changes in the shear behaviors, failure modes, and shear strengths. It was found that the concrete strength and number of transverse rebars in the crestbond rib were significantly related to its shear resistance. After the initial bearing resistance behavior of the concrete dowel, a relative slip occurred in all the specimens. However, its rigid behavior to shear loading decreased the ductility of the shear connection. The cross-sectional area of the crestbond rib was also shown to have a minor effect on the shear resistance of the crestbond rib shear connector. The failure mechanism of the crestbond rib shear connector was complex, and included compression, shear, and tension. As a failure mode, a crack was initiated in the middle of the concrete slab in a vertical direction, and propagated with increasing shear load. Then, horizontal cracks occurred and propagated to the front and rear faces of the specimens. Based on the results of this study, a design shear strength equation was proposed and compared with previously suggested equations.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.627-643
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• 1995

The resistance to fracture of the restored tooth may be influenced by many factors, among these are the cavity dimension and the physical properties of the restorative material. The placement of direct composite resin restorations has generally been found to have a strengthening effect on the prepared teeth. It is the purpose of this investigation to study the relationship between the cavity isthmus and the fracture resistance of a tooth in composite resin restorations. In this study, MO cavity was prepared on the maxillary left first molar and then filled with composite resin. Three dimentional model with 3049 nodes and 2450 8-node blick elements was made by the serial photographic method and isthmus (1/4, 1/3, 1/2 and 2/3 of intercusplal distance between mesiobuccal cusp tip and mesiolingual cusp tip) was varied. Two types of model(B and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall and R model was left unfilled. A load of 1500N was applied vertically on the node from the lingual slope of the mesiobuccal cusp. The results were as follows : 1. There was a significant decrease of stress resulting in increase of fracture resistance in B model when compared with R model. 2. When it comes to stress distribution, the stress was concentrated in the facio-gingival line angle and the buccal side of the distal margin of the cavity in both Band R model. 3. With the increase of the isthmus width, the stress decreased in the area of the facio-gingival line angle, and increased in the area of facio-gingival line angle as well as the buccal side of the distal margin of the cavity in B model. In R model, the stress increased both in the area of facio-gingival line angle and the buccal side of the distal margin of the cavity, therefore the possibility of crack increased. 4. As the width of cavity increased, in B model, the direction of crack moved from horizontal to vertical on the facio-gingival line angle and the facio-pulpal line angle. In R model, the direction of the crack was horizontal on the facio-gingival line angle and moved from horizontal to the $45^{\circ}$ direction on the facio-pulpal line angle.

• 한국지반공학회논문집
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• 제30권1호
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• pp.75-91
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• 2014

횡하중이 작용하는 짧은말뚝의 지지거동에 영향을 미칠 수 있는 인자들에 대한 분석을 문헌과 사례를 통해 제시하였다. 가상고정점은 $1/{\beta}$를 일률적으로 적용하는 것보다 지반의 강성에 따라 적용되어야 하고, Chang(1937)법과 P-Y 해석법이 유사한 고정점 위치를 예측하였다. 점성토의 수평지지력은 실내와 현장이 다른 특성을 보였고, 평가방법은 실내시험에서는 모두 과소예측을 하였고, 현장은 과소 또는 과대 예측을 한다. 현장실험에서는 Hansen(1961)법이 비교적 실측에 근접한 예측결과를 제시하였다. 사질토의 수평지지력 평가법은 실내시험에서는 과대예측을 하였고, 현장도 대부분 과대예측한다. 경험적 수평지지력 분포도를 사용한 Zhang(2005)법이 비교적 실측에 근접한 예측 결과를 보였다. 본 연구에서는 점성토 지반에 대하여 극한수평지지력 분포도 및 산정방법을 제안하였다. 제안법은 다른 방법에 비해 실측과 가장 근접한 결과를 추정하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권3호
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• pp.225-231
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• 2008

This study evaluated whether there is a difference between a conventional titanium distraction device and a TiN-coated device in terms of implant osseointegration after horizontal distraction osteogenesis in narrow alveolar bone. Four adult mongrel dogs, each weighing $9{\sim}10kg$, were used in this study. The lower premolars were extracted and horizontal distraction was performed with conventional titanium distraction devices (group 1) or TiN-coated devices (group 2). After an 8-week consolidation period, the implants were installed, and the dogs were sacrificed after another 8 weeks. The osseointegration around the implants was evaluated histomorphologically. There was one failure in experimental group 1 because of fracture of the device. Direct bone contact was achieved and there were no significant differences between the control group and experimental groups 1 and 2 in terms of osseointegration around the implants at 8 weeks. In summary, intraoral distraction osteogenesis is a good option for augmenting severely atrophied alveolar ridges, and the TiN-coated device may be useful because of its advantages, which include surface hardness, corrosion resistance, and reduced bacteria.

• 한국지반공학회지:지반
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• 제13권1호
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• pp.19-34
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• 1997

과압밀된 점토현장에서 수행한 콘관입시헙 자료를 지구통계학 방법으로 분석하였다. 임의로 위치한 28개의 콘 사운딩 자료(A현장)와 일관되게 위치한 38개치 콘 사운딩 자료(B현장)분석에 이용되었다. 크리깅기법을 이용하여 두 현장의 콘 저항에 대한 베리어그램을 개발했다. 개발된 배리오그램은 현장에서와 수직적 상관거리 및 수평적 상관거리를 규명하는데 이용되었으며 이의 결과는 두 시험결과를 상호비교하려면 샘플링이 수평상관지리 이내에서 수행되어야하는 최적샘 플링설계로 이용된다. 베리오그램의 분석결과는 두 현장의 지질학적 형성이 수직적 및 수평적으로 큰 차이가 없음을 확인할 수 있었다. A현장에서의 크리깅한 콘 저항치를 3차원적으로 나타낸 표면은 콘 저항치의 공간적 변동을 이해하는데 도움을 주며 또한 지구통계학적으로 분식된 3차원적 표면은 분석된 현장의 어느위치에서나 최적의 콘 저항치를 나타낼 수 있다는 것을 의미한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.207-212
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• 2002

The actual buckling of the railroad track structure is suspected to be a complex interaction between the vertical, lateral and torsional modes. To make the analysis tractable, however, most studies restrict themselves to either the vertical or the horizontal plane. Based on a comprehensive and realistic three-dimensional track model developed in the previous study, three dimensional buckling analysis of CWR track subjected to temperature load was performed. Using the study on buckling temperature and mode, sensitivity of track components such as tie spacing, ballast resistance, stiffness of pad-fastening system and rail size were investigated.

• Journal of Microbiology
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• 제45권6호
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• pp.590-592
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• 2007

We report the isolation of Salmonella enterica serotype Typhimurium phage type DT104 (CCARM 8104) from swine in Korea. The CCARM 8104 isolate was resistant to nalidixic acid and showed reduced susceptibility to quinolones. The CCARM 8104 isolate had a missense mutation, Asp87Asn, in the quinolone resistance-determining region in gyrA and produced PSE-1. The CCARM 8104 isolate carried two different class 1 integrons, and the PSE-1 ${\beta}$-lactamase gene was inserted into a 1,200 bp class 1 integron. The presence of DT104 with pse-1 in an integron located in a plasmid and reduced susceptibility to quinolone in swine pose a significant threat of possible horizontal spread between swine and humans.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.407-414
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• 2000

The friction pendulum type seismic isolation system (FPS) has been developed to provide a simple and effective way to achieve earthquake resistance for buildings . The major advantages are: the isolation frequency can be easily achieved by designing a curvature of the surface and does not depend on the supported weight of a structure. The function of carrying vertical load is separated to the function of providing horizontal stiffness. Next the friction provides sufficient energy dissipation to protect the structure from earthquake response and resistance to the weak external disturbances such as wind load and ground vibrations due to traffic. In this paper, the friction coefficients are evaluated from number of experiments on the FPS test specimens. The relations between friction coefficient and the test waveform, velocity, and pressure are reviewed and further works are discussed.

• Steel and Composite Structures
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• 제29권3호
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• pp.309-318
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• 2018

Steel girders are the structural members often used for passing long spans. Mostly being subjected to patch loading, or concentrated loading, steel girders are likely to face sudden deformation or damage e.g., web breathing. Horizontal or vertical stiffeners are employed to overcome this phenomenon. This study aims at assessing the feasibility of a machine learning method, namely the support vector machines (SVM) in predicting the patch loading resistance of longitudinally stiffened webs. A database consisting of 162 test data is utilized to develop SVM models and the model with best performance is selected for further inspection. Existing formulations proposed by other researchers are also investigated for comparison. BS5400 and other existing models (model I, model II and model III) appear to yield underestimated predictions with a large scatter; i.e., mean experimental-to-predicted ratios of 1.517, 1.092, 1.155 and 1.256, respectively; whereas the selected SVM model has high prediction accuracy with significantly less scatter. Robust nature and accurate predictions of SVM confirms its feasibility of potential use in solving complex engineering problems.