• 한국인터넷방송통신학회논문지
• /
• 제15권2호
• /
• pp.221-227
• /
• 2015

등가 전송선로에 기초한 모드 전송선로 이론 (Modal Transmission-Line Theory: MTLT)을 이용하여 이중 샌드위치 Rib-형 층으로 구성된 나노 크기의 격자 구조형 편광 무의존성 결합기 (Grating-Assisted Polarization-Insensitive Coupler: GA-PIC)의 편광특성을 자세하게 분석하였다. 제안한 나노 크기의 GA-PIC의 편광 무의존성 조건을 얻기 위하여 샌드위치 rib형 층의 굴절률과 두께에 따라 변하는 quasi-TE 모드와 quasi-TM 모드의 결합길이를 분석하였으며, 격자구조의 광학적 변수들인 격자두께와 격자주기에 따른 결합길이의 영향도 분석하였다. 수치해석 결과, 수백 나노미터 크기의 GA-PIC는 이중 샌드위치 층과 격자구조의 구조적, 물질적 변수들을 잘 선택함으로써 구현할 수 있음을 보였다.

• 한국산학기술학회논문지
• /
• 제18권11호
• /
• pp.747-754
• /
• 2017

본 논문은 강관과 콘크리트가 함께 축력에 저항하는 합리적인 콘크리트 강관구조형식에 대해 무피복상태에서 내화성능을 높이는 연구이다. 콘크리트 강관구조는 내부 콘크리트로 인한 열저항 성능이 매우 우수하지만, 국내에서는 일정시간 동안 내화성능을 확보하도록 규정하고 있는 내화구조시스템으로 피복처리가 되지 않는 상태에서는 활발하게 적용되지 못하고 있다. 따라서 콘크리트충전 강관구조 기둥의 구조성능을 향상시키기 위하여 강관 내측면에 부착하는 리브요소를 개발하고 그것의 효과적인 형상을 개발하는 연구로서 콘크리트 강관기둥 내측면에 Corrugated Rib를 부착하여 구조적압축 및 좌굴 저항능력을 향상시키는 CFT 시스템을 개발하고자 한다. 이에 대한 연구 결과, 강관 내면 부착 리브의 적용으로 내화시 CFT 기둥의 내력상승에 의한 좌굴방지를 확인하였고, 내화성능기준 또한 만족하였다. 따라서 본 연구를 통해 개발된 강재리브(Corrugate rib)구조 보강재를 활용한 CFT의 공법은 내화피복 없이 구조 및 내화성능을 만족시키는 것으로 판단된다. 향후 rib의 다양한 형태를 변수로 하는 연구와 공장생산에서 공정을 효율화 시키고, 경제성 있는 시스템으로 활용할 수 있도록 추가 연구가 필요할 것으로 판단된다.

• 한국재료학회지
• /
• 제13권1호
• /
• pp.53-58
• /
• 2003

For the rib materials in PDP(plasma display panel), an effective method to improve the mechanical properties is to form a composite material by reinforcing a glass matrix with rigid fillers, such as alumina and titania powders. In this study, two types of ribs with different volume percent of fillers and with different glass matrix were tested for hardness, Young's modulus with the Berkovich indentation. As a result, cracks appeared around at the load of 1345 mN for the dense type of rib, while porous one endured until 2427 mN without any crack formation. Young's modulus and hardness decreased at the range: 90∼65 GPa, 9∼4 GPa, respectively as a function of indent load. Thus, a new method with nanoindenter represents a possible evaluation method for mechanical properties of barrier ribs.

• 한국안전학회지
• /
• 제29권5호
• /
• pp.74-81
• /
• 2014

This study proposes an advanced type of a micropile system. The proposed micropile system consists of perfobond ribs installed steel rod to improve shear capacity between the thread and the grout, and partially expanded drill holes to increase resistance capacity between the grout and the ground. This study contains experimental evaluations on the proposed micropile system to verify the shear capacity of perfobond rib installed on the steel rod and the load-carrying capacity of shear key created by the partially expanded drill hole. Push-out tests were conducted on a rolled screw thread and steel rods which perfobond ribs are installed instead of rolled screw, in order to compare their load-carrying capacity and behavioral characteristics. As a result, it was confirmed that the perfobond-rib steel rods show much superior structural behavior in terms of initial stiffness, ultimate load, and ductile behavior.

• 대한기계학회논문집
• /
• 제19권5호
• /
• pp.1211-1219
• /
• 1995

An upper bound elemental technique (UBET) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flash and flashless forgings. The simulation for flash and flashless forgings are applied axisy mmetric and plane-strain closed-die forging with rib-web type cavity. Inverse triangular and inverse trapezoidal elements are used to analyze flashless forging. The analysis is described for merit of flashless precision forging. Experiments have been carried out with pure plasticine billets at room temperature. Theoretical predictions of the forging load and the flow pattern are in good agreement with experimental results.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.886-888
• /
• 2009

We fabricated flexible electronic paper display(EPD) by using toner particles on plastic (PC) substrate. We observed the relationship between contrast ratio and changes of rib structures. One is a fabrication of ribs on bottom substrate. The display with ribs on bottom substrate had higher contrast ratio about 46% than display with ribs on top substrate. The other is a change of density of rib. The less density of ribs fabricated, the higher the contrast ratio become.

• 한국임상수의학회지
• /
• 제25권3호
• /
• pp.182-186
• /
• 2008

An 11-year-old mixed breed male dog was presented with a thoracoabdominal wall mass of 3-year duration. Initial tentative diagnosis of osteosarcoma was made. Despite chemotherapy treatment, 72 days following the date of presentation, the dog was euthanized. Based upon necropsy and histopathologic findings, the tumor was definitely diagnosed as a combined type osteosarcoma of the rib. At necropsy examination, the tumor extended the left kidney and diaphragm, but distant metastasis was not found. The tumor's weight was 2.3kg and that was 38.3% of the dog's weight. This case report describes the clinicopathological, computed tomographic, histopathologic and immunohistochemical findings of extensive rib osteosarcoma in a small breed dog.

• Steel and Composite Structures
• /
• 제42권6호
• /
• pp.791-804
• /
• 2022

As a type of semi-rigid connection, the top and seat angle connections are popular in current structures owing to their good cyclic performance and simple erection. However, their stiffness and load bearing capacity are relatively insufficient. This study proposes two strengthening methods to further increase the stiffness and strength of bolted-angle joints while maintaining satisfactory energy dissipation capacity (EDC) and ductility. Cyclic loading tests were conducted on six joint specimens with different strengthened angle components. Based on the test results, the influence of the following important factors on the cyclic behavior of steel joint specimens was investigated: the position of the rib stiffeners (edge rib stiffeners and middle rib stiffener), steel strength grade of rib stiffeners (Q345 and Q690), and additional stiffeners or not. In addition, the finite element models of these specimens were built and validated through a comparison of experimental and numerical results. The stiffness and bearing capacity of the bolted-angle joints could be improved significantly by utilizing the novel strengthened joints proposed in this study. Moreover, this can be achieved with almost no increase in the amount of steel required, and the EDC of this joint could also satisfy the requirements of seismic codes from various countries.

• 한국조경학회지
• /
• 제35권4호
• /
• pp.48-56
• /
• 2007

This study was to understand the component that affects the formative beauty and to present the direction of bridge design for improving the image of urban landscape to survey the visual effect and landscape Preference by the change of bridge type. The results of this study are as follows. In the results of image analysis by bridge types, the images of one-arch bridges are unique and interesting, whereas more than two successive arched bridge were harmonize, stable, consecutive and regular. In the case of the arch rib, braced-rib arch bridge was assessed that complicated, diverse and interesting more than solid-rib arch bridge. The results of factor analysis on the psychological factor were classified into three categories: orderliness, aesthetic and symbolism. In the results of analysis on psychological factors by bridge types, the orderliness and symbolism were different in the position of path, and the number of arches, too. In case of arch rib, symbolism was different. In the preference analysis, they showed a sensitive reaction in the background of building. In the results of the relativity preference and psychological factor, according to aesthetic, symbolism and orderliness, there was an effect on the background of building. And, there showed the high effect in order of aesthetic, orderliness and symbolism in the background of mountain and building. This study should be objective raw data of the arch bridge design for improving the urban landscape. In the future, aesthetic variables like colors or textures should be considered for more exact evaluation.

• 한국구조물진단유지관리공학회 논문집
• /
• 제17권2호
• /
• pp.33-44
• /
• 2013

강바닥판의 구조상세에 대하여 많은 연구가 이루어지고 있으나, 대부분의 연구가 표준형의 U-rib를 대상으로 실시되었을 뿐, 강바닥판 건설초기의 개단면리브형식에 대한 연구는 미진한 것으로 조사되었다. 본 연구에서는 공용연수 31년된 개단면세로리브형식의 강바닥판 교량의 피로균열 발생 원인을 조사하기 위하여 실교통류하에서의 계측 데이터를 통하여 대상구조상세의 거동 특성을 분석하였다. 또한 상세구조해석을 통하여 대상교량을 통과하는 대표트럭하중을 추정하고, 상세영향면해석을 이용하여 대상구조상세의 응력 및 변형특성을 분석하였다. 이들 분석에 기초하여 피로균열이 발생된 대상구조상세의 보강방안을 제시하고, 이에 대한 타당성을 검증하였다. 연구결과, 개단면리브에서의 피로균열의 발생원인은 개단면부에서의 전단변형에 의한 응력증가 및 차량의 이동에 따른 교번응력의 발생에 기인하는 것으로 조사되었으며, 국부구조상세에 대한 피로설계에서는 구조상세의 거동특성이 충분히 반영된 상세해석에 근거한 설계를 실시하는 것이 중요하다는 것을 알 수 있었다.