PSC 교량의 보강공법에 대한 실험적 연구

김현호,김기봉,정인근,송재필 中央大學校 建設環境硏究所 2002 環境科學硏究 Vol.13 No.2

많은 수의 국도상의 교량이 교통량 증가 및 차량의 대형화에 따라 내하력 증가의 필요성이 시급히 제기되고 있다. 본 연구에서는 국도상 교량 중 대다수를 차지하고 있는 프리스트레스트 콘크리트(Prestressed Concrete, PSC) 교량에 대해 유리섬유 부착 공법과 외부 후긴장 보강 공법을 적용하여 내구성 및 내하력의 증가방안을 확인하고자 한다. 실험체는 표준도면의 1/5 축소모델로서 지간길이 6m이며 총 15개의 실험체를 제작하여 정적 및 피로실험을 수행하였다. 실험 결과, 유리섬유 및 외부 후긴장 보강 방법을 적용하였을 때 균열하중 및 파괴하중의 크기가 증가되었고, 처짐의 감소효과와 균열에 대한 억제 능력이 증가하였다. 그리고 보강 실험체가 피로파괴 반복회수도 증가하며 유리섬유 보강 실험체의 경우 외부 후긴장 실험체보다 피로성능이 더 우수한 것으로 나타났다. 본 연구 결과를 통해 적용된 보강 기법이 노후된 PCS 교량의 성능증가와 수명 연장의 효과가 큰 것을 확인하였다. Most of the bridges on national road are needed capacity-enhancement, because of the increase of heavy traffic loads and aging of bridges. Among those bridges, prestressed concrete(PSC) bridges take a large portion. But there are not many related researches about strengthening PSC bridges. In this study, the practicability of strengthening methods for PSC beam were studied by the static and fatigue experimental method. For the experiment, 1/5 scale and six meters long PSC beams were made with concrete slabs. Glass fiber sheeting and external post-tensioning methods were used for strengthening PSC beams. Total 15 beams were made for static test and fatigue test. As a result, the strengthening methods, which used in this study, are efficient at increasing cracking load and failure load, to decrease deflection and prevent cracks. The experimental results show that the failure cycle of strengthened members are increased compare to non-strengthened members. The members strengthened with glass fiber show better enhancement in fatigue problem than the members strengthened with external post-tensioning method. With these experimental results, it can be said that the strengthening methods used in this study are efficient at extending the life time of aged PSC bridges.

일부 조선업 근로자의 직업성 요통 발생실태 및 위험요인에 관한 연구

고상백,김형식,최홍렬,김지희,송인혁,박준한,박종구,장세진,차봉석 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.1

목적 : 이 연구에서는 한 사업장의 동일한 코호트내에서 직업성 요통의 발생 및 발생원인에 대해 조사하고자 하였다. 방법 : 연구대상은 1995년 12월 현재 한 조선업체에 종사하는 근로자 중에서 1995년 12월 31일 까지 요통이 이미 발생한 근로자와 1995년 당시 검진 미수검자를 제외한 9,784명을 연구대상으로 하였다. 요통 발생군은 1996년부터 1998년까지 3년간 추적 관찰하여 요통으로 4일 이상 통원 또는 입원치료를 받은 근로자로 하였다. 발생률은 요통발생 당시 연도를 기준으로 하여 해당 연도의 4일 이상 신규치료를 받은 중등도 이상의 요통근로자를 분자로 하였고, 해당년도 사업장의 종사하는 근로자 총수(과거 요통자 제외)를 분모로 간주하였다. 요통 발생군은 외상성 요통과 직업관련성 요통으로 대별하였으며, 위험요인과 질병 발생간의 관련성을 보기 위한 Cox모형에서 그 위험도를 파악하고자 할 때에는 직업성 요통만을 환자군으로 선정하였다. 결과 및 결론 . 요통 발생률은 근로자 천명당 1998년 3.1명, 1997년 8.8명, 1996년 7.8명이었다. 요통점유율의 범위는 10.99∼25.66이었다. 연령별 요통 발생률은 30대, 40대에서 높은 발생률을 보였다. 진단명에 따른 발생률은 추간판 탈출증, 염좌, 척추골절, 척추분리증, 척추협착증 순이었다 직업성 요통 발생자들의 직업적 요인을 알아보기 위하여 요통 발생 당시 작업형태를 알아본 결과, 물건을 들다가 66명(35.3%)이 발생하여 가장 큰 빈도를 차지하였고, 물건을 옮기는 과정에서 19명(10.2%)이 발생하여 2위를 차지하였고, 넘어지거나(8.6%), 물건을 당기는 자세(8.0%), 값자기 일어서다(7.5%) 순으로 요통이 발생하였다. 직업성 요통에 영향을 주는 일반적 특성 및 직업적 특성에 판한 상대위험도 및 95% 신뢰구간를 구한 결과, 요통발생에 영향을 주는 유의한 변수로는 체질량 지수(비만도), 교대여부, 중량물 취급여부였다. Objectives : This study was conducted to estimate the incidence rate, and to identify the risk factors for the occupational low back pain among shipyard workers. Methods : The study subjects consisted of 9,784 workers who were employed in a ship-building industry (excluded workers who had a history of low pack pain before 1995 or did not take periodic health examination in 1995) . The cases were 220 people who experienced back pain from January 1, 1996 to December 31, 1998. To assess risk factors for occupational low back pain, Cox propotional hazard model was used. Results : During the recent three years from 1996 to 1998, the incidence rate per 1,000 persons was 7.8 in 1996, 8.8 in 1997, and 3.1 in 1998. The main causes of work-related low back pawn were sprain, strain and disc herniation. Lifting was the most common cause of back pain (35.3%) , and carrying (10.2%) and pulling (8.0%) were followed. In Cox proportional harzard model, independent risk factors for back pain were body mass index(R.R. ; 1.54, 95% C.1. : 1.06-2.25), shift work(R.R. ; 1.65, 95% C.1. : 1.19-2.28), and lifting heavy material(R. R., 3.95, 95% C.1. : 2.29-6.82). Conclusions . This study suggests that the risk factors of back pawn In shipyard work-ers were body mass index, shift work and lifting.

AGT 시스템의 동적 증가계수 시뮬레이션

송재필,김기봉,정인근,김현호 中央大學校 建設環境硏究所 2002 環境科學硏究 Vol.13 No.2

무인궤도운전열차(Automated Guide-way Transit, AGT) 시스템의 접지력 및 교량-차량의 동적 응답을 구하기 위해 노면조도가 있는 주행로를 운행하는 AGT 시스템에 대한 동적 운동방정식을 유도하였다. AGT 시스템의 차량은 3차원 11 자유도 모델로 이상화하였고, 교량은 3차원 프레임 모델로 단순화하였다. 동적 운동방정식의 해를 구하기 위하여 컴퓨터 프로그램을 개발하였고, 해석된 결과는 실험자료의 결과치와 비교 분석하였다. 본 연구에서 개발된 프로그램의 해석결과 AGT 교량, 차량 그리고 노면요철의 상호 작용에 의한 교량과 차량의 동적 응답을 구하여 정밀한 교량의 동적증가계수를 산정할 수 있었다. The equations of motion for an automated guide-way transit(AGT) system running on a path with roughness have been derived to investigate dynamic responses and wheel loads of moving vehicles of the AGT system. A vehicle of the AGT system is idealized as three-dimensional model with 11 degree-of-freedom, and a bridge is modelized with three F.E. method. The computer program is developed to solve the dynamic equations, and analytical results are verified by comparing the results with experimental ones. As a result, the computer program which developed in this study can be used for estimate the dynamic responses of bridge and vehicle due to dynamic interaction of bridge, vehicle and surface roughness, and with these results the dynamic increment factor of bridge can be obtained.

A Comparison between In-situ PET and ENVI-met PET for Evaluating Outdoor Thermal Comfort

Jeong, Da-in,Park, Kyung-hun,Song, Bong-guen 한국생태환경건축학회 2016 한국생태환경건축학회 논문집 Vol.16 No.1

제주 차귀도 연안해역 미생물 분포 및 이화학적 특성

문영건,김만철,이준백,송춘복,여인규,김종만,박근태,손홍주,최우봉,허문수 한국환경과학회 2006 한국환경과학회지 Vol.15 No.3

차광이 차나무 수관 주변의 미기상과 신초의 품질에 미치는 영향

송인관(In Kwan Song),오은의(Eun Ui Oh),황재종(Jae Jong Hwang),송승운(Seung Woon Song),김봉찬(Bong Chan Kim),송관정(Kwan Jeong Song) 한국차학회 2013 한국차학회지 Vol.19 No.4

The changes in the micro climatic conditions around the canopy and the quality characteristics by shading in new young shoots of 'Asanoka' and 'Lyohu' tea plants were examined to collect basic data on the development of cultural practices for producing food materials with high quality by the cover of shading nets. Shading treatments were conducted by covering the tea canopy with black polyethylene nets with a shading rate of 95, 75, 55, and 35%, and a covering structure was designed to create an air space 30 cm in height above the canopy using a supporting pole. The light transmissivity through the shading nets in the 4th tea season and air temperature around canopy in the 2nd and 3rd tea seasons was measured to examine the effects of shading on the micro climatic conditions. The contents of total nitrogen, total amino acids, theanine, cathechins, caffeine, vitamin C, tannin, and crude fiber and chroma (Hunter a) were analyzed from new young shoots in different tea seasons to determine the effect of shading on the shoot quality. Light transmissivity through 95% and 75% shading nets was similar, but 55% and 35% shading nets were different from that on the current product indicated by the manufacturer. The changes in air temperature by the cover of shading nets was larger in the canopy surface and air space above canopy than the internal canopy. There was a tendency of the daily maximum air temperature to be high with no shading and low with a cover of 95% shading nets, but there was no difference in the daily minimum temperature. In a comparison of the shoot quality affected by the cover of 95% and 75% shading nets, the content of amino acids, theanine, caffeine, and crude fiber showed tendencies to increase, but the content of cathechins, vitamin C, and tannin showed tendencies to decrease and the chromaa value showed a distinct decline toward a green color withno shading.

Periodontitis is associated with rheumatoid arthri­tis: a study with longstanding rheumatoid arthritis patients in Korea

( In Ah Choi ),( Jin-hee Kim ),( Yong Mi Kim ),( Joo Youn Lee ),( Kyung Hwa Kim ),( Eun Young Lee ),( Eun Bong Lee ),( Yong-moo Lee ),( Yeong Wook Song ) 대한내과학회 2016 The Korean Journal of Internal Medicine Vol.31 No.5

Background/Aims: A cross-sectional study was undertaken to investigate the association between severity of periodontitis and clinical manifestation of rheu­matoid arthritis (RA). Methods: Two hundred sixty-four RA patients and 88 age- and sex-matched con­trols underwent dental exam. Additionally, clinical manifestations including disease activity and anti-citrullinated protein antibodies were evaluated in RA patients. Results: The prevalence of moderate or severe periodontitis was higher in RA pa­tients compared to controls (63.6% vs 34.1%, p < 0.001). In markers of periodontal inflammation, bleeding on probing was correlated with disease activity score 28 (r = 0.128, p = 0.041), RA disease duration (r = 0.211, p = 0.001), erythrocyte sedimen­tation rate (ESR; r = 0.141, p = 0.023), anti-cyclic citrullinated peptide antibody (r = 0.183, p = 0.009), and anti-citrullinated α-enolase peptide-1 antibody (r = 0.143, p = 0.025). Gingival index was correlated with RA duration (r = 0.262, p < 0.001), ESR (r = 0.162, p = 0.009), anti-cyclic citrullinated peptide antibody (r = 0.203, p = 0.004) and anti-citrullinated α-enolase peptide-1 antibody (r = 0.225, p < 0.001). Periodontal structural damage represented by probing pocket depth and clinical attachment level were less in RA patients with human leukocyte antigen (HLA)-DRB1 shared epitope compared than those without shared epitope (p = 0.005 and p =0.006, respectively). Conclusions: The prevalence of moderate or severe periodontitis was increased in RA patients compared to controls. Periodontal inflammation was correlated with RA disease duration, ESR, and anti-citrullinated protein antibodies. Peri­odontal structural damage was less in RA patients with HLA-DRB1 shared epi­tope.

Urine protein-to-creatinine ratio in a random spot urine collection is a reliable measure of proteinuria in lupus nephritis

( In Ah Choi ),( Eun Young Lee ),( Yeong Wook Song ),( Eun Bong Lee ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.1

Background: The accurate measurement of proteinuria is critical to the clinical management of lupus nephritis. The 24-hr urine collection has been commonly used to objectively measure the amount of proteinuria but is a laborious procedure for patients and is prone to cause collection error. Alternatively, spot urine ratio of protein to creatinine (P/Cr) has been introduced as an alternative representation of the 24-h urine collection in various kinds of kidney diseases with proteinuria. However, it is not known whether spot urine P/Cr can replace 24hr urine protein in lupus nephritis. Methods: This is a retrospective study investigating the association of random spot urine P/Cr and 24hr urine protein in patients with biopsy-proven lupus nephritis. A total of 286 samples of random spot urine and concurrent 24hr-urine collections from 120 patients were analyzed. All the patients were diagnosed as systemic lupus erythematosus according to the revised criteria of American College of Rheumatology and were enrolled from Seoul National University Hospital between May 2004 and July 2010. Results: In 286 selected samples, 24 hr urine protein excretion ranged from 42 mg/day to 36,080 mg/day. The range of 24 hr urine P/Cr was 0.04 to 49.72. Random urine P/Cr ranged from 0.06 to 51.40. There was a strong correlation between 24 hr urine protein excretion and random urine P/Cr (r=0.774, p<0.001). A strong correlation (r=0.939, p<0.001) was also found between 24hr urine P/Cr and random P/Cr. The spot urine P/Cr was correlated well with 24hr urineprotein until 24 hr urine protein is up to 8 g/day (r=0.742, p<0.001). This result shows that random spot urine P/Cr is a reliable substitute of 24 h urine protein excretion in a wide range of urine protein excretion. Conclusion: This study shows that random spot urine P/Cr is well correlated with 24 hr urine protein in a wide range of 24hr urine protein excretion. The result supports the use of random spot urine P/Cr inb screening and monitoring of proteinuria in patients with lupus nephritis.

Auto Line Defect Detection System For LCD Panel Review & Repair Machine

Lee Woo Chul,Song Jun Bong,Lim In Sik,Hwang Jae Ho,Jung Tae Joong,Park Chan Woo,Jung Taek Sun,Lee Won Jeong 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In TFT-LCD panel fabrication process, there are many kinds of defects which cause mal-functioning of TFT circuits, due to problems in manufacturing processes , machines and particles in the air. Line defect is main cause of yield loss in TFT-LCD fabrication process and detecting them is very difficult because of their tiny size. we propose high-speed and high precise automated line defect detection system. In order to high speed image grabbing, TTL position signal generated by XY gantry motion controller is used to synchronizing signal of strobe illuminator and camera. The effective image processing algorithms to find defects using the microscope image is adopted. In order to judge whether previously extracted defect is Line Defect or not, detect zone which represent Gate, Data layer zone line defect mainly caused is adopted also. The vision processing can detect very small defects (under 2um) in 90% success ratio and 60mm/sec high scan speed @10X microscopic lens. In addition, through the implementation embeded image processing PC, low image processing time(100msec) in each image and it can be parallelized with image scanning.

Low-level laser therapy induces the expressions of BMP-2, osteocalcin, and TGF-β1 in hypoxic-cultured human osteoblasts.

Pyo, Se-Jeong,Song, Won-Wook,Kim, In-Ryoung,Park, Bong-Soo,Kim, Cheul-Hong,Shin, Sang-Hun,Chung, In-Kyo,Kim, Yong-Deok Baillière Tindall ; Springer London 2013 Lasers in medical science Vol.28 No.2

<P>The aim of this study was to examine the effect of low-level laser therapy (LLLT) on the cell viability and the expression of hypoxia-inducible factor-1s (HIF-1s), bone morphogenic protein-2 (BMP-2), osteocalcin, type I collagen, transforming growth factor-β1 (TGF-β1), and Akt in hypoxic-cultured human osteoblasts. Human fetal osteoblast cells (cell line 1.19) were cultured under 1?% oxygen tension for 72?h. Cell cultures were divided into two groups. At the experimental side, low-level laser (808?nm, GaAlAs diode) was applied at 0, 24, and 48?h. After irradiation, each cell culture was incubated 24?h more under hypoxia. Total energy was 1.2, 2.4, and 3.6?J/cm(2), respectively. Non-irradiated cultures served as controls. Comparisons between the two groups were analyzed by t test; a p value <0.05 was considered statistically significant. Hypoxia resulted in a decrease in the expression of type I collagen, osteocalcin, and TGF-β1 (p?<?0.001, p?<?0.001, and p?<?0.01, respectively). Cell viability and BMP-2 expression were not decreased by hypoxic condition. On the other hand, LLLT on hypoxic-cultured osteoblast promoted the expression of BMP-2, osteocalcin, and TGF-β1 (p?<?0.05, p?<?0.01, and p?<?0.001, respectively). Cell proliferation was also increased time-dependently. However, hypoxia decreased in type I collagen expression (p?<?0.001), and LLLT did not affect type I collagen expression in hypoxic-cultured osteoblasts. Furthermore, LLLT inhibited HIF-1 and Akt expression in hypoxic conditioned osteoblasts. We concluded that LLLT induces the expression of BMP-2, osteocalcin, and TGF- β1 in 1?% hypoxic-cultured human osteoblasts.</P>