FRP판으로 휨 보강된 철근콘크리트 보의 장기거동

서수연,트랜 하이반,김강수,윤현도,이건철 대한건축학회 2023 대한건축학회논문집 Vol.39 No.3

The purpose of this study is to evaluate the long-term behavior of RC beams reinforced by fiber reinforced polymer (FRP) strip such asnear-surface mounted retrofit (NSMR) and externally bonded retrofit (EBR). The 30% loads of nominal strength of the RC beams wereapplied and continued for up to 49 days. The loads were increased up to 55% of the nominal strengths of RC beams at 50 days afterperforming flexural retrofit by using FRP with the planned retrofit methods and have been kept for almost one year. During all loadingperiods, the deflections and the strains of rebars and FRPs were measured at least once every week. The long-term behavior of all specimenswas evaluated and the deflection variations were predicted by considering the long-term effect on the nonlinear sectional analysis result of thereinforced RC beams. As a result, in the specimen reinforced with partially de-bonded NSM FRP, the strains of the FRP strip were notconcentrated on the center of the beam and the magnitude at the center was less than that with the fully bonded FRP. In addition, it ispossible to properly simulate the deflections of the beams strengthened with FRP exposed to a long-term load by considering the long-termeffect on the sectional analysis result. 본 연구에서는 FRP판으로 표면매립과 표면부착 보강된 RC 보들의 장기거동을 평가하고자 한다. RC 보에 공칭강도의 30%에 해당하는 하중을 가력하여 42일을 지속시킨 후, 하중 작용상태에서 계획된 보강방법에 따라 FRP 판으로 휨보강하고 1주일의 양생기간을 거쳐 50일째에는 보강후 공칭강도의 55%로 하중을 증대시키고 약 1년동안 하중을 유지시켰다. 모든 가력기간동안의 처짐과 인장철근 및 FRP의 변형률을 1주일에 최소 1회이상 계측하였다. 모든 실험체의 장기거동을 평가하였고 단면해석결과에 장기재하 효과를 고려하여 처짐의 변화를 평가하였다. 그 결과, 부분 비부착 FRP로 표면매립보강된 실험체는 비부착구간에서 FRP 변형률이 보의 중앙에 집중되지 않음에 따라, 중앙부 변형률이 완전부착인 경우에 비하여 낮게 나타났다. 또한 단면해석결과에 장기거동 효과를 고려함으로써 장기하중에 노출된 FRP 보강 RC 보의 처짐을 적절하게 예측할 수 있는 것으로 나타났다.

점모양내측맥락막병증 환자에서 병발한 소실다발흰점증후군 1예

서수연,박종호,이승민,박성후,이지은,변익수 대한안과학회 2018 대한안과학회지 Vol.59 No.9

Case summary: A 23-year-old female complained about sudden visual loss in the right eye. Best-corrected visual acuity (BCVA) was 20/100 in the right eye and 20/20 in the left eye. In fundus examination and optical coherence tomographic images, subfoveal choroidal neovascularization (CNV) with hemorrhage was observed in the right eye, accompanied by multiple lesions of atrophic pigmentation on the posterior pole in both eyes. We diagnosed the patient as punctate inner choroidopathy (PIC) and CNV in the right eye, and treated her using three monthly intravitreal injections of bevacizumab (Avastin®, Roche, Basel, Switzerland; 1.25 mg/0.05 mL). The CNV regressed and the BCVA improved to 20/20. Two years later, she complained of visual impairment in her left eye. The BCVA was 20/40. Fundus photography revealed numerous small white dots around the posterior pole and optic disc. Disruption of the photoreceptor layer was seen in optical coherence tomography images. Small white dots were observed as multiple hyperfluorescent dots in fluorescein angiography and hypofluorescent spots in indocyanine green angiography. An enlarged blind spot was observed in the visual field. We diagnosed her as multiple evanescent white dot syndrome (MEWDS). One month after systemic steroid treatment, the multiple white dots disappeared and the BCVA improved to 20/20. Conclusions: We determined that PIC and MEWDS, which belong to the white dot syndrome, could occur in a patient at different times. 목적: 점모양내측맥락막병증으로 진단된 환자에서 소실다발흰점증후군이 병발한 1예를 경험하여 보고하고자 한다. 증례요약: 특이병력이 없는 23세 여자 환자가 1주 전부터 시작된 우안의 시력 저하로 내원하였다. 최대교정시력은 우안 20/100, 좌안20/20이었다. 안저검사와 빛간섭단층촬영 영상에서 양안 후극부에 다발성의 탈색소성 병변과 우안 맥락막신생혈관과 황반하 출혈이 관찰되었다. 점모양내측맥락막병증에서 병발한 우안의 맥락막신생혈관을 진단하였고 우안은 유리체강 내로 베바시주맙(Avastin®, Roche, Basel, Switzerland; 1.25 mg/0.05 mL)을 총 3회 주사하였다. 맥락막신생혈관은 퇴행하였고, 후극부에 색소성 반흔을 남긴 채 우안 시력은 20/20까지 회복되었다. 2년 뒤 좌안의 시력 저하로 내원하였고 최대교정시력은 20/40이었다. 안저검사에서 다수의 백색반점이 좌안의 후극부와 시신경유두 주변에서 관찰되었다. 빛간섭단층촬영에서 광수용체 신호가 감소되어 있었다. 형광안저혈관조영에서 다수의 과형광의 반점이 관찰되었으며, 인도사이아닌그린혈관조영에서는 이보다 많은 수의 저형광 반점이 관찰되었다. 시야검사에서는 암점의 확대가 있었다. 소실다발흰점증후군으로 진단하고, 경구 스테로이드 치료 1개월 후 병변은 소실되었으며 시력은 20/20으로 호전되었다. 결론: 흰점증후군에 속하는 질환인 점모양내측맥락막병증과 소실다발흰점소실증후군이 시간을 두고 함께 발생할 수 있음을 경험하여 보고하는 바이다.

기둥형상과 보 깊이 변화에 따른 외부 기둥-넓은 보 접합부의 이력거동에 관한 연구

서수연,윤승조,윤용대 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.3

In wide beam, how the effective width is decided is very important since the calculation of stiffness and strength of the beam is based on it. Several research works have been conducted by previous researcher to find the effective width of wide beam. And also New zealand code prescribes a formula to calculate it. However these didn't consider the effectiveness of spandrel beam in exterior joint, which affects the behavior of wide beam. In this study, therefore, an evaluation on seismic resistance capacity of the exterior column-wide beam joint with spandrel beam is performed. Five specimens are designed to have variable test parameters; that are column width, column depth and the beam depth. Cyclic loads are applied to the beam end of test specimen according to the test procedure suggested by ACI committee. Before the test, previous formula to calculate the effective of wide beam were reviewed and the strength of specimens was predicted by using these. From the test, it was found that the ultimate strength of specimen linearly increased when the beam or column depth increased; the variation of column depth was more sensitive to the strength of specimens. The comparison result by using previous formula in predicting the strength of specimen shows that most close prediction can be possible when uses Wight's one. Other two formula codified in ACI or New zealand code underestimate test results.

아동의 건강행태 실태와 건강증진활동 실시 전·후 향상비교 신체활동을 통한 신체적·정서적 상태 변화 중심으로

서수연,신혜선,이종민 초록우산 어린이재단(구 한국복지재단) 2017 어린이재단 발간물 Vol.2017 No.1

Validation of the Korean Depressive Symptom Inventory-Suicidality Subscale

서수연,류혜라,Carol Chu,Melanie Hom,Megan L. Rogers,Thomas Joiner 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.5

Objective: The present study aimed to validate a Korean version of the self-report Depressive Symptom Inventory-Suicidality Subscale (DSI-SS). Methods: 553 South Korean undergraduate students (aged 18–34 years, 74.8% females) completed questionnaires. Participants completed Korean versions of the self-report Depressive Symptom Inventory-Suicidality Subscale (DSI-SS), Beck Depression Inventory-II (BDI-II), Insomnia Severity Index (ISI), Beck Scale for Suicide Ideation (BSS), and a measure of suicide-related symptom history. Results: Results indicated that the DSI-SS demonstrated excellent internal consistency (α=0.93) and strong convergent validity with the BDI (r=0.57, p<0.01), ISI (r=0.27, p<0.01), and BSS (r=0.70, p<0.01). DSI-SS scores also significantly differentiated between those reporting a history of suicide attempts compared to non-suicide attempters [t (38.80)=-3.28, p<0.05]. Conclusion: Given the brevity of this measure, and evidence for its validity, the Korean version of the DSI-SS may be particularly promising for clinical and empirical use as a screening tool among South Korean undergraduates.

FRP판을 이용한 콘크리트 보강에서 보강방법에 따른 부착성능

서수연,오재길,최기봉,Seo, Soo-Yeon,Oh, Jae-Gil,Choi, Ki-Bong 대한건축학회 2011 대한건축학회논문집 Vol.27 No.8

Recently, FRP (Fiber Reinforced Polymer) has been widely applied in retrofit of concrete member owing to its ease construction and high structural capacity compared to other materials. External Bond Retrofit (EBR) using FRP sheet or plate is most popular method for flexural retrofit of concrete member. In strengthened concrete member using this method, however, problems such as dismantling of FRP were founded after retrofit. This causes a strength reduction of the retrofitted member. To resolve this problem, Near-Surface-Mounted Rertofit (NSMR) method was developed and being studied. In this paper, bond capacities of EBR and NSMR using FRP plate were studied experimently and results were compared each other. Main variables in the test were retrofit method, bond length and existence of shear key. From the test results, it was found that the member strengthened by NSMR had almost 1.5 times higher bond strength than that by EBR. The contribution of shear key was not observed when the splitting failure of concrete governed.

Longitudinal Course of Depression Scores with and without Insomnia in Non-Depressed Individuals: A 6-Year Follow-Up Longitudinal Study in a Korean Cohort

서수연 AMER ACAD SLEEP MEDICINE 2013 SLEEP Vol.36 No.3

재활로봇에 대한 작업치료사의 인식 조사

서수연,김시은 대한고령친화산업학회 2019 대한고령친화산업학회지 Vol.11 No.1

Objective : In the present study, the demand for rehabilitation robots is increasing, We will examine the recognition of rehabilitation robots. Method : From October 31 to November 9, 2018, 62 questionnaire surveys were conducted for occupational therapists in Busan and Kyungnam provinces, Respectively. A total of 100 questionnaires were distributed, and questionnaires collected via internet links and direct visits 62 parts. The collected data were analyzed using SPSS (Statistical Package for Social Science for Window) Technical statistical analysis was performed using Version 21.0. Result : I have heard of questions about whether you know or have heard of rehabilitation robots 41 persons (66.1%) responded to the questionnaire, and the rehabilitation robots that they knew were hand function training The highest rate of exercise rehabilitation was 53 persons (85.7%) and the need for rehabilitation robot 32 persons (51.6%) answered yes to the questionnaire, and patients were given appropriate and high quality intervention To provide "was the highest rate of 27 persons (43.9%). Conclusion : Recognition of rehabilitation robots by occupational therapists is low, but the need for rehabilitation robots It is necessary to provide facilities and rehabilitation robot program and education to provide rehabilitation robot service. In order to activate the rehabilitation robot systematically in the future. 목적 : 본 연구는 재활로봇에 대한 국내외의 수요가 높아지는 현시점에서 국내 작업치료사들의 재활로봇에 대한 인식도를 조사해보고자 한다. 연구방법 : 2018년 10월 31일부터 11월 9일까지 부산, 경남 지역 작업치료사 대상으로 설문조사를 실시하였 다. 배부된 설문지는 총 100부였으며, 인터넷 링크와 직접 방문으로 회수된 설문지는 62부였다. 수 집된 자료는 통계 프로그램인 SPSS(Statistical Package for Social Science for Window) Version 21.0을 사용하여 기술 통계분석을 실시하였다. 연구결과 : 재활로봇에 대해 알고 있거나 들어본 적이 있는지에 관한 문항에서 들어본 경험은 있다고 응답한 대상자가 41명(66.1%)으로 가장 많았으며, 알고 있는 재활로봇으로는 손 기능 훈련 등의 운동재활 분야가 53명(85.7%)로 가장 높았으며 재활로봇에 의한 치료 프로그램이 필요한지에 한 항목에서는 그렇다고 응답한 대상자가 32명(51.6%)이였고 필요한 이유에 대한 응답으로는 “환자들에게 적절하 고 질 높은 중재를 제공하기 위해” 라는 응답의 비율이 27명(43.9%)로 가장 높았다. 결론 : 작업치료사들의 재활로봇에 대한 인식도와 요구도가 높게 나와 지역별로 재활로봇과 관련된 시설과 재활로봇 프로그램 및 교육이 마련되어 재활로봇 서비스를 제공해야 할 필요가 있다는 것을 알 수 있다. 향후 체계적으로 재활로봇의 활성화를 위해서 지속적인 협회 차원의 보수교육 및 워크숍 등 의 교육 기회 제공 및 제정적인 지원이 마련되어야 할 것이다.

페인트, 접착제, 실란트에서 방출되는 휘발성유기화합물 특성연구

서수연,장성기,임준호,이우석 한국대기환경학회 2008 한국대기환경학회 학술대회논문집 Vol.- No.-

A mechanical acupuncture instrument mitigates the endoplasmic reticulum stress and oxidative stress of ovariectomized rats

서수연,Suk Yun Kang,권오상,Se kyun Bang,Soo Phil Kim,Kwang-Ho Choi,Ji Young Moon,Yeonhee Ryu 한국한의학연구원 2019 Integrative Medicine Research Vol.8 No.3

Background: Acupuncture has become a common complementary and alternative treatment approach for anxiety and depression. However, there is little research on the detailed mechanism of acupuncture therapy relieving depression. Previously, 17β-estradiol (E2) was shown to prevent oxidative stress and endoplasmic reticulum (ER) stress in ovariectomized (OVX) rats. This study investigated whether stimulation of Sanyinjiao (SP6) using a mechanical acupuncture instrument can alleviate depression-like behavior caused by estrogen deficiency in OVX rats. Furthermore, we found that acupuncture reduced ER stress and oxidative stress-related proteins expression. Methods: The OVX operation was performed on female SD rats that were separated into four groups: The E2 (2.5 μg/kg, i.p.) injection group (OVX + E2), the OVX group (OVX), and the OVX with acupuncture stimulation group (OVX + SP6). Non-acupoint stimulation group (OVX + NonAcu). The acupuncture point stimulation began three weeks after surgery. The depressive behavior was analyzed by the forced swim test and open field test. The 8-OHDG, BiP, Sigma receptor 1, pJNK, PDI, Ero1-Iα and Calnexin protein levels were evaluated by immunoreactivity in the amygdala. Results: Acupuncture stimulation reduced depressive behavior and altered depression-related proteins. Stimulation of SP6 decreased the immobility time of the FST and altered the ER stress and oxidative stress marker proteins, such as 8-OHDG, BiP, pJNK, PDI, Ero1-Ia and Calnexin. Conclusion: Our results indicated that acupuncture at SP6 showed a significant antidepressant-like effect on an OVX-induced depression rat model by mitigation of ER stress and oxidative stress in amygdala.