• 한국강구조학회 논문집
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• 제12권3호통권46호
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• pp.251-258
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• 2000

강구조물과 부재들의 지진 손상도 평가법에 새롭게 접근하기 위하여 강한 지진하중을 받는 강재 교각에 대해 수치해석을 수행하였다. 새로운 손상도 평가법에서 파괴 상태에 대한 기준은 지진하중이 재하되는 동안에 응력집중이 가장 심한 단면의 한 부분에서 누적소성변형율의 값이 90%에 이르게 되는 때를 의미한다. 단주기 특성의 지진하중에 대해서는 소성변형율의 누적에 의한 국부좌굴 파괴보다는 허용변위를 초과하는 전체좌굴에 의한 파괴가 지배적인 것으로 밝혀졌다. 장주기 특성의 지진하중에 대해서는 소성변형율이 강재교각 하부의 모서리 부분 요소에 누적되면서 누적 소성변형율에 의한 국부좌굴로 파괴되는 결과를 보였다.

• Smart Structures and Systems
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• 제4권1호
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• pp.1-17
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• 2008

This study proposes a conceptual framework of in-situ vibration tests and analyses for quality appraisal of non-slender, cast-in-place piles with irregular cross-section configuration. It evaluates a frequency index from vibration recordings to a series of impulse loadings that is related to total soil-resistance forces around a pile, so as to assess if the pile achieves the design requirement in terms of bearing capacity. In particular, in-situ pile-vibration tests in sequential are carried out, in which dropping a weight from different heights generates series impulse loadings with low-to-high amplitudes. The high-amplitude impulse is designed in way that the load will generate equivalent static load that is equal to or larger than the designed bearing capacity of the pile. This study then uses empirical mode decomposition and Hilbert spectral analysis for processing the nonstationary, short-period recordings, so as to single out with accuracy the frequency index. Comparison of the frequency indices identified from the recordings to the series loadings with the design-based one would tell if the total soil resistance force remains linear or nonlinear and subsequently for the quality appraisal of the pile. As an example, this study investigates six data sets collected from the in-situ tests of two piles in Taipu water pump project, Jiangshu Province of China. It concludes that the two piles have the actual axial load capacity higher than the designed bearing capacity. The true bearing capacity of the piles under investigation can be estimated with accuracy if the amplitude of impact loadings is further increased and the analyses are calibrated with the static testing results.

• 대한치과교정학회지
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• 제50권5호
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• pp.314-323
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• 2020

Objective: To identify the available evidence on the effects of rapid maxillary expansion (RME) with three-dimensional imaging and provide meta-analytic data from studies assessing the outcomes using computed tomography. Methods: Eleven electronic databases were searched, and prospective case series were selected. Two authors screened all titles and abstracts and assessed full texts of the remaining articles. Seventeen case series were included in the quantitative synthesis. Seven outcomes were investigated: nasal cavity width, maxillary basal bone width, alveolar buccal crest width, alveolar palatal crest width, inter-molar crown width, inter-molar root apex width, and buccopalatal molar inclination. The outcomes were investigated at two-time points: post-expansion (2-6 weeks) and post-retention (4-8 months). Mean differences and 95% confidence intervals were used to summarize and combine the data. Results: All the investigated outcomes showed significant differences post-expansion (maxillary basal bone width, +2.46 mm; nasal cavity width, +1.95 mm; alveolar buccal crest width, +3.90 mm; alveolar palatal crest width, +3.09 mm; intermolar crown width, +5.69 mm; inter-molar root apex width, +2.85 mm; and dental tipping, +3.75°) and post-retention (maxillary basal bone width, +2.21 mm; nasal cavity width, +1.55 mm; alveolar buccal crest width, +3.57 mm; alveolar palatal crest width, +3.32 mm; inter-molar crown width, +5.43 mm; inter-molar root apex width, +4.75 mm; and dental tipping, 2.22°) compared to pre-expansion. Conclusions: After RME, skeletal expansion of the nasomaxillary complex was greater in most caudal structures. Maxillary basal bone showed 10% post-retention relapse. During retention period, uprighting of maxillary molars occurred.

• 복식
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• 제53권5호
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• pp.79-95
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• 2003

The purpose of this study is firstly to survey the social and cultural background of 20th century and women´s status, and to identify what the ideal body is like and what the elements of outer garment and underwear are and the techniques to incarnate the ideal beauty. Various papers are referenced for theoretical study and the elements and techniques of underwear are analyzed based on photographical materials. This paper concludes as follows. In 1960´s, ideal beauty was small bust, long legs, which showed extremely slim Mini-skirt look. Thinly or no padded brassiere were worn for small bust, and pants-style short panty girdles were popular as they used to wear pants frequently. Lycra replaced all the closures, bones, seams and gave freedom with light weight. In 1970´s, a natural human body without sex specific was in vogue. Therefore, the non-structural knits without a pad or lining or the shirts dress were widespread for a Natural look and the naturally molded brassiere or girdles were worn as the underwears. In 1980´s, the women with powerful muscle appear which emphasized liveliness and healthfulness. The body conscious represented by wide shoulder, plump breast, accented waist, small hips, and long legs has been embodied. Outer garments emphasized women power and healthy beauty with Power suit and Form-fitting style, and underwears made the breast plump with padded brassiere and emphasized waist and hips with waspie. In 1990´s, ideal beauty was slim body with big bust and the outer garments emphasized body line of women with Hourglass silhouette. Push-up bra which emphasizes the valley of breast and supports the breast upward and the control tights for slim waist, flat abdomen, small hips, and long and slim legs have been useful as underwears. Multi-functional micro-fiber has been ideal for sculpting women body.

• Archives of Plastic Surgery
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• 제40권4호
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• pp.374-379
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• 2013

Background To date, various types of acellular dermal matrix (ADM) have been developed for clinical use. AlloDerm is the most familiar type of ADM to most surgeons in breast reconstruction. It is prepared by freeze-drying. CG CryoDerm is the first form of ADM that requires no drying process. Therefore, theoretically, it has a higher degree of preservation of the dermal structures than AlloDerm. We conducted this study to compare the clinical course and postoperative outcomes of patients who underwent direct-to-implant breast reconstructions using AlloDerm and those who did using CG CryoDerm. Methods We performed a retrospective analysis of the medical records in a consecutive series of 50 patients who underwent direct-to-implant breast reconstruction using AlloDerm (n=31) or CryoDerm (n=19). We then compared the clinical course and postoperative outcomes of the two groups based on the overall incidence of complications and the duration of drainage. Results The mean follow-up period was 16 months. There were no significant differences in the overall incidence of complications (seroma, infection, skin flap necrosis, capsular contracture, and implant loss) between the two groups. Nor was there any significant difference in the duration of drainage. Conclusions CG CryoDerm has the merits of short preparation time and easy handling during surgery. Our results indicate that CG CryoDerm might be an alternative allograft material to AlloDerm in direct-to-implant breast reconstruction.

• 한국패류학회지
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• 제7권1호
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• pp.76-86
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• 1991

A scanning electron microscopic stuey on the glochidial encystment study on the golchidal encystment and excystment of Anodonta fukudai on Acheilognathus yamatsutae, a common natural hostfish, was conducted. The glochidium easily attached to the unscaled surfaces of the host fish such as the fins, lips, and the wall of the buccal cavity. For this study, the fins infected with the glochidia wer mainly observed in a series. The process of encystment was slowly progressed, for 21-25 hours for the early cyst and for 2-4 days for the thick walled cyst. The process of excystmint was visually detected on the 12th day since the attachmint was occurred. The first visible sign was a little tear of the cyst wall covering the hinge and marginal zones of the juvenile clam and once the little sign was appeared the progress of emerging and dettachmint of the juvenile clam from the host was finished relatively in short time. During the process of the encystmint, the cells participationg in covering the attached glochidirm were seened mainly supplied by migration from the surroundings. the shapes of the cells migrating and covering the glochidium were considerably changed and the surface structures of the cells lost their normal pattern of the surface ridges. The unstable forms of the cells were observed almost all throughout the period of the glochidial attachment. No cells of the host epithelium, which were still attached to the juvenile clam energing from the cyst, were observed. The most juvenile clams escaped from the cysts were a little bigger than the glochidia and they were still possessed of the golchidial hooks even though much degenerated. The first growth line was appeared on the shell valves of the juvenild clam when observed right after dettachment.

• Wind and Structures
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• 제23권2호
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• pp.157-169
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• 2016

The structural integrity of tube bundles represents a major concern when dealing with high risk industries, such as nuclear steam generators, where the rupture of a tube or tubes will lead to the undesired mixing of the primary and secondary fluids. Flow-induced vibration is one of the major concerns that could compromise the structural integrity. The vibration is caused by fluid flow excitation. While there are several excitation mechanisms that could contribute to these vibrations, fluidelastic instability is generally regarded as the most severe. When this mechanism prevails, it could cause serious damage to tube arrays in a very short period of time. The tubes are therefore stiffened by means of supports to avoid these vibrations. To accommodate the thermal expansion of the tube, as well as to facilitate the installation of these tube bundles, clearances are allowed between the tubes and their supports. Progressive tube wear and chemical cleaning gradually increases the clearances between the tubes and their supports, which can lead to more frequent and severe tube/support impact and rubbing. These increased impacts can lead to tube damage due to fatigue and/or wear at the support locations. This paper presents simulations of a loosely supported multi-span U-bend tube subjected to turbulence and fluidelastic instability forces. The mathematical model for the loosely-supported tubes and the fluidelastic instability model is presented. The model is then utilized to simulate the nonlinear response of a U-bend tube with flat bar supports subjected to cross-flow. The effect of the support clearance as well as the support offset are investigated. Special attention is given to the tube/support interaction parameters that affect wear, such as impact and normal work rate.

• 한국터널지하공간학회 논문집
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• 제17권6호
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• pp.695-702
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• 2015

원심모형시험은 최근의 기계적, 이론적 발전에 따라 그 활용도와 정확성이 높아지고 있다. 원심모형시험은 원지반 응력을 효과적으로 재현할 수 있으므로 주위 지반 또는 암반과 상호작용을 하는 터널과 같은 지하구조물의 거동을 모사하기 적합하다. 본 연구에서는 병렬 터널의 지진시 동적 거동을 원심모형시험을 통하여 분석하였다. 터널 모델링시 지진에 의해 발생하는 최대 가속도 저감을 위하여 Flexible segment를 고려하였으며 Flexible segment의 두께가 얇은 경우와 두꺼운 경우를 각각 고려하였다. 시험 결과 Flexible segment의 지진시 터널 구조물에 발생하는 최대 가속도 저감 효과를 확인하였다. 그러나 Flexible segment가 얇은 경우 단주기파 적용시 최대가속도의 저감효과는 없었고, 두꺼운 경우 기반암 가속도가 클 경우 보다 효과적임을 확인하였다. 또한 동일 모델에 대하여 3차원 수치해석을 수행하여 지진시 거동을 파악한 결과, 시험 결과와 유사한 경향을 보임을 확인할 수 있었다.

• 한국전산구조공학회논문집
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• 제33권1호
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• pp.55-61
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• 2020

국내 고도성장기 이후 본격 건설되기 시작한 사회 기반 시설물은 노후화가 빠르게 진행되고 있다. 특히 사고 발생 시 대량 인명 피해로 직결될 수 있는 교량, 터널 등의 대형 구조물에 대한 안전성 평가가 필요하다. 하지만 기존의 유선 센서 기반의 Structural Health Monitoring(SHM)을 개선한 무선 스마트 센서 네트워크는 짧은 신호 도달거리로 인해 경제적이고 효율적인 시스템 구축이 힘들다. 따라서 LoRa LPWAN 시스템은 사물인터넷의 확산과 더불어 저전력 장거리 통신이 각광을 받고 있으며, 이를 구조 건전성 모니터링에 응용함으로써 경제적이면서도 효율적인 모니터링 시스템 구축이 가능하다. 본 연구에서는 LoRa LPWAN 기반의 무선 계측센서 기술동향을 조사하였으며, LoRa LPWAN 기반의 무선 계측센서 설치 및 유지관리 방안을 제안한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1174-1187
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• 2007

모노레일시스템은 차량외관의 친밀성, 교량 상하부의 슬림한 구조, 저렴한 공사비, 짧은 시공기간 등 미관, 경제성, 시공성에서 다양한 장점이 인정되어 시가지 경량전철의 유력한 대안으로서 여러도시에서 검토 및 제안되고 있다. 또한, 최근에 대구시에서는 도시철도3호선의 시스템으로 모노레일을 채택하여 기본설계를 진행하고 있다. 이러한 국내의 추세에 맞추어 본 고에서는, 해외사례와 현재 수행중인 대구도시철도 기본설계를 중심으로 하여, 모노레일교량의 계획 및 설계에 관한 주요사항을 소개하였다. 먼저, 해외의 모노레일 교량 사례를 분석하였으며, 대구도시철도3호선 기본설계에서 적용하고 있는 주요설계기준을 소개하였다. 또한, 과좌형 모노레일의 대표적인 구조형식인 PSC궤도빔과 강궤도빔에 대하여 계획, 설계 및 제작 방법을 개괄적으로 설명하였다. 본 고의 내용이 모노레일 교량의 계획 및 설계에 관심이 있는 기술자들에게 도움이 되기를 기대한다.