• Title/Summary/Keyword: 폭-두께 비

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Change in arch width in extraction vs nonextraction treatment (발치 및 비발치 치료 전후 악궁 폭경의 변화)

  • Jeon, Ji-Yun;Kim, Su-Jung;Kang, Seung-Goo;Park, Young-Guk
    • The korean journal of orthodontics
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    • v.37 no.1 s.120
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    • pp.65-72
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    • 2007
  • Objective: This study was performed to investigate the influences of extraction and nonextraction treatment on smile esthetics by measuring dental arch width changes. Methods: Pretreatment and posttreatment study models of 30 first premolar extraction cases and 30 nonextraction cases were randomly selected to determine whether extraction treatment results in narrow dental arches, and a consequent unaesthetic smile. Arch widths were measured from the cusp tips of the canines and the first molars. Posterior arch widths were also measured at a constant arch depth derived by averaging randomly chosen nonextraction models. Results: The intercanine widths increased significantly in the extraction sample, whereas the intermolar widths decreased significantly. The arch width at a standardized arch depth was significantly wider in the extraction subjects. Conclusion: These results elucidate that constriction in arch width is not a materialized consequence of extraction treatment. It leads to postulate that an esthetically compromising effect from narrow dental arches on smile is hardly anticipated with extraction treatment.

Dynamical Behavior of Bidirectional Monolithic Nd:YAG Ring Laser (양방향으로 발진하는 일체형 Nd:YAG 고리레이저에서의 출력변조현상)

  • 홍정미;손승현;송홍주;길상근;이재철
    • Korean Journal of Optics and Photonics
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    • v.6 no.2
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    • pp.115-121
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    • 1995
  • 본 논문에서는 일체형, Nd:YAG 고리 레이저에서 서로 반대방향으로 진행하는 두 모드의 비선형적인 상호작용에 의한 출력 불안정 현상을 조사하였다. 실험을 통하여 두 모드가 각각 단일 종모드로 발진함을 확인하였고, 레이저가 발진하는 임계치 부근의 낮은 펌핑수준을 유지하여 다중모드간의 경쟁이나 단방향 발진에 의한 출력 불안정이 아님을 확인하였다. 또한 잘 알려진 시스템 고유의 감쇄진동과 구별되는 현상임을 보였다. 두 모드간의 손실차가 클수록 이 출력의 변조주파수는 증가하고 변조폭이 줄어 들어 안정화 되며 단방향 발진이 일어난다.

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Finite Element Analyses on Ultimate Compressive Strength of Longitudinally Stiffened Polygonal Sections (종방향 보강재로 보강된 다각형 단면 기둥구조의 극한강도 해석)

  • Choi, Byung Ho;Park, Seong Mi;Hwang, Min Oh
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.40-40
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    • 2011
  • 현재 일반적으로 활용되고 있는 원통형 쉘구조로 이루어진 타워구조의 대형화가 추진되면서 제작, 운반 편의성, 단면효율성, 경제성 제고를 위해 다각형단면 기둥구조물의 활용이 대두되고 있다. 하지만 다각형 단면 기둥구조의 극한강도에 대한 자료가 충분치 않고 관련 기준이나 지침이 명확히 제시되고 있지 않은 실정이다. 본 연구에서는 원통형 쉘구조물을 다각형구조물로 대체하여 제작될 경우 축방향 압축에 대한 내하력 향상 효과를 수치해석적으로 검토해 보고자 한다. 해석모델은 지름 2m, 두께 20mm인 원형강관 프로토타입 풍력타워 구조를 참고로 하여 이에 내접하도록 결정한 6~12각형 단면 형상으로써 높이 10,000mm인 3차원 기둥모델을 구현하였고 유한요소프로그램인 ABAQUS를 이용하여 해석하였다. 각 subpanel의 중앙에 종방향 보강재를 설치하였을 때 국부좌굴에 대한 내하력 변화를 비교하기 위해 종방향보강재로 보강한 모델을 구성하여 비교 해석을 수행하였다. 종방향 보강재의 제원은 미국 SSRC 제안식을 기준으로 삼았다. 탄성좌굴해석을 통해 탄성좌굴모드 형상을, 비선형비탄성해석을 통해 최종파괴모드 및 극한강도를 얻었다. 보강 전 후의 탄성좌굴 해석 결과로부터 최소모드의 고유치 값을 비교하였다. 각 subpanel 단면 중심부에 한 개의 보강재를 설치한 경우 탄성좌굴강도가 4배 가량 증가하였다. 이로부터, 보강재(n=1) 설치에 따라 유효 폭두께비가 1/2로 감소하는 효과를 확인 할 수 있다. 비선형해석결과로부터 subpanel의 단면중심에 보강재를 설치한 경우 보강재가 위치한 곳에 고정점이 형성되어 이를 중심으로 국부 좌굴모드에 변화가 생기는 것이 확인되었다. 이러한 변화는 다각형 단면 기둥구조의 내하력 성능, 즉 국부좌굴강도에 영향을 준다. 충분한 강성을 갖는 종방향 보강재가 설치된 경우, 극한상태에서도 유효폭두께비가 줄어드는 것과 같은 강도 향상 효과를 확인할 수 있다. 이러한 사실은 각 해석결과 극한강도를 DIN code, Migita와 Fukumoto의 제안식, SSRC 설계제안식 등과의 비교를 통해 확인할 수 있었다.

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An Analytical Evaluation on Buckling Resistance of Tapered H-Section Deep Beam (춤이 큰 웨브 변단면 H형 보의 휨내력에 대한 해석적 평가)

  • Lee, Seong Hui;Shim, Hyun Ju;Lee, Eun Taik;Hong, Soon Jo;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.19 no.5
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    • pp.493-501
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    • 2007
  • Recently, in the domestic amount of materials,curtailment and economic efficiency security by purpose, tapered beam application is achieved, but the architectural design technology of today based on the material non-linear method does not consider solutions to problems such as brittle fracture. So, geometric non-linear evaluation thatincludes initial deformation, width-thickness ratio, web stiffener and unbraced length is required. Therefore, in this study, we used ANSYS, a proven finite elementanalysis program,and material and geometric non-linear analysis to study existing and completed tapered H-section as deep beam's analysis model. Main parameters include the width-thickness ratio of web, stiffener, and flange brace, with the experimental result obtained by main variable buckling and limit strength evaluation. We made certain that a large width-thickness ratio of the web decreases the buckling strength and short unbraced web significantly improves ductility.

A Numerical Study on Flexural Strength with the Spreading of Upper Reinforcement of Girder into the Adjoining Slab (보 상부철근의 슬래브 내 분산배근에 따른 휨강도의 수치해석적 연구)

  • Park, Jung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1179-1185
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    • 2007
  • The study of girder-to-column joints under experiment and numerical analysis was carried out to evaluate change of the flexural capacity of the joints with the 2-layer upper reinforcement of girder within rectangular section and the single-layered upper reinforcement at the girder flange. According to the analysis results using the flange width, the flange thickness and the location of reinforcements in the upper flange as variables, in the models with a same effective width, the increasing rate of capacity has nothing to do with the flange width with a same effective width. However, the capacity of the models with the upper reinforcements arranged close to the rectangular beam section is larger than that of the models with the upper reinforcements arranged remotely from the rectangular section. If the range of arrangement fur reinforcement exceeds the effective width, despite of increasing the flange thickness, the capacity is not increased.

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A Study on Miniaturization and Design Flexibility of an Elliptic-Response Open-Loop Resonator Filter (타원응답 개방 루프 공진기 필터의 소형화 및 설계 유연성에 관한 연구)

  • 안창수;김영식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.11
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    • pp.1082-1089
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    • 2004
  • In this paper, miniaturization of an elliptic-response open-loop resonator filter and design flexibility using similarity transformation of the coupling matrix are proposed. Moreover, the filter with wider fractional bandwidth is designed by the proposed method. In order to verify the proposed method, three 4th-order elliptic-response open-loop resonator filters with a relative bandwidth of 4 % at the center frequency of 2.0 GHz are designed. One is realized with constant-width microstrip line resonator and the others are implemented with different-width microstrip line resonator. Compared with the former one, the latter have shown the size reduction of 13 % and 25 %, respectively. Since it may not be possible to implement the resonators with very narrow spacing for the required coupling coefficient filters with two different configurations representing same response characteristic through similarity transformation of the coupling matrix are proposed. From this design flexibility, a filter with a relative bandwidth of 8 % at the center frequency of 2.0 GHz is designed with realizable design parameters.

Strength of Axially Loaded Concrete-Filled Tubular Stub Column. (중심축하중을 받는 콘크리트충전 각형강관단주의 내력)

  • Kang, Chang-Hoon;Oh, Young-Suk;Moon, Tae-Sup
    • Journal of Korean Society of Steel Construction
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    • v.13 no.3
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    • pp.279-287
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    • 2001
  • This paper presents an experimental and analytical study on the behavior of concrete-filled tubular stub columns concentrically loaded in compression to fail. Total eleven specimens were tested and test parameters are the depth-to-thickness ratios of steel tube and the ratio of concrete cylinder strength-to-yield stress of steel tube. Depth-to-thickness ratios of steel tube between 20.22

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The design of a single layer antireflection coating on the facet of buried channel waveguide devices using the angular spectrum method and field profiles obtained by the variational method (Variational 방법으로 구한 필드 분포와 Angular Spectrum 방법을 사용한 Buried채널 도파로 소자 단면의 단층 무반사 코팅 설계)

  • 김상택;김형주;김부균
    • Korean Journal of Optics and Photonics
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    • v.13 no.1
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    • pp.51-57
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    • 2002
  • We have calculated the optimum refractive index and normalized thickness of a single layer antireflection coating on the facet of buried channel waveguides as a function of waveguide width for several waveguide depths using the angular spectrum method and field profiles obtained by the effective index method (EIM) and the variational method (VM), respectively, and discussed the results. In the area of large waveguide width, the optimum parameters of a single layer antireflection coating obtained by both methods are almost the same. However, as waveguide width decreases, the parameters obtained by the VM approach those of a single layer antireflection coating between cladding layer and air, while those obtained by the EIM do not approach those, and the difference between the two parameters is large. The tolerance maps of the quasi-TE and quasi-TM modes obtained by the VM for square waveguides are located in almost the same area regardless of refractive index contrast, while those obtained by the free space radiation mode (FSRM) method for refractive index contrast of 10% are located in the different area. Thus, we think that the tolerance maps obtained by the VM are more exact than those obtained by the FSRM method.

Evaluation on the In-plane Bending Moment for T-joints with Square Hollow Structural Sections (각형강관 T형 접합부의 면내 휨모멘트 평가)

  • Park, Keum Sung;Lee, Sang Sup;Choi, Young Hwan;Bae, Kyu Woong
    • Journal of Korean Society of Steel Construction
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    • v.21 no.5
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    • pp.451-459
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    • 2009
  • The purpose of this study was to evaluate the in-plane bending moment for T-joints made of cold-formed square hollow steel sections. In the previous studies, the T-joint was shown not to have an obvious peak load, and the failure mode was the main chord flange failure at the branch-width-to-chord-width ratio ($\beta$) of below 0.71. Based on the experimental results, including the tests conducted by Zhao, the deformation limit of 1% B was proposed for ${16.7{\leq}2{\gamma}(=B/T){\leq}33}$ and ${0.34{\leq}{\beta}(=b_{1}/B){\leq}0.71}$. Then, the ultimate in-plane bending strength was shown to be Mu=1.5${\cdot}$M1% B. The existing strength formulae for the original T-joint were investigated and were determined to be the main chord flange failure for the branch-squared T-joint. The bending strength formulae of CIDECT and other researchers were compared with the test results. Finally, a reasonably good agreement with Zhao's formula was found. Therefore, the design guidelines were presented based on Zhao's strength formula for T-joints.

Characteristics of Bearing Capacity under Square Footing on Two-layered Sand (2개층 사질토지반에서 정방형 기초의 지지력 특성)

  • 김병탁;김영수;이종현
    • Journal of the Korean Geotechnical Society
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    • v.17 no.4
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    • pp.289-299
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    • 2001
  • 본 연구는 균질 및 2개층 비균질지반에서 사질토지반 상에 놓인 정방형 기초의 극한지지력과 침하에 대하여 고찰하였다. 본 연구는 얕은기초의 거동에 대한 정방형 기초의 크기, 지반 상대밀도, 기초 폭에 대한 상부층의 두께 비(H/B), 상부층 아래 경계면의 경사($\theta$) 그리고 지반강성비의 영향을 규명하기 위하여 모형실험을 수행하였다. 동일 상대밀도에서 지지력 계수($N_{{\gamma}}$)는 일정하지 않으며 기초 폭에 직접적으로 관련되며 지지력계수는 기초 폭이 증가함에 따라 감소하였다. 기초크기의 영향과 구속압력의 영향을 고려하는 Ueno 방법에 의한 극한지지력의 예측값은 고전적인 지지력 산정식보다 더 잘 일치하며 그 값은 실험값의 65% 이상으로 나타났다. $\theta$=$0^{\circ}$인 2개층 지반의 결과에 근거하여, 극한지지력에 대한 하부층 지반의 영향을 무시할 수 있는 한계 상부층 두께는 기초 폭의 2배로 결정되었다. 그러나, 73%의 상부층 상대밀도인 경우는 침하비($\delta$B) 0.05 이하에서만 이 결과가 유효하였다. 경계면이 경사진 2개층 지반의 결과에 근거하여, 상부층의 상대밀도가 느슨할수록 그리고 상부층의 두께가 클수록 극한지지력에 대한 경계면 경사의 영향은 크지 않는 것으로 나타났다. 경계면의 경사가 증가함에 따른 극한침하량의 변화는 경계면이 수평인 경우($\theta$=$0^{\circ}$)를 기준으로 0.82~1.2(상부층 $D_{r}$=73%인 경우) 그리고 0.9~1.07(상부층 $D_{r}$=50%인 경우) 정도로 나타났다.Markup Language 문서로부터 무선 마크업 언어 문서로 자동 변환된 텍스트를 인코딩하는 경우와 같이 특정한 응용 분야에서는 일반 문자열에 대한 확장 인코딩 기법을 적용할 필요가 있을 수 있다.mical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes. the RSC circle, but also to the logistics system in the SLC circle. Thus, the RSLC model can maximize combat synergy effects by integrating the RSC and the SLC. With a similar logic, this paper develops "A Revised System of Systems with Logistics (RSSL)" which combines "A New system of Systems" and logistics. These tow models proposed here help explain several issues such as logistics environment in future warfare, MOE(Measure of Effectiveness( on logistics performance, and COA(Course of Actions) for decreasing mass and increasing velocity. In particular, velocity in logistics is emphasized.

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