줄눈콘크리트 포장의 줄눈 거동 측정

윤경구,김동호,홍창우,이주형 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

In this research, the early-age movements of joint at JPCP(Jointed Plain Concrete Pavement) were measured by field tests. The field tests were carried out for 5 days just after concrete placement, for 1 day after 52 and 72 days on Chung-Ang Expressway construction site in Dan-Yang on the 28th and 29th of May 2001. The joint movements were measured by demec gauge and clip gauge. The results of regression analysis for the data measured during early 5 days showed that the joints of No.4, No.5, No.6, No.10, No.13, and No.15 could be considered as a moving joint. From data analysis on July 20, the joints of No.2, No.9, and No.10 showed the significant correlations from the minus value of coefficient of regression. As a result of regression data on August 8, joint movements occurred at all joints. Joint freezing and closure could be judged from the regression analysis using joint opening and total temperature measured at field tests.

요인 실험분석에 의한 SB 라텍스 개질 콘크리트의 강도예측

윤경구,이주형,홍창우 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

The purpose of this study was to provide the evaluation and prediction of strengths of SB latex modified concrete(LMC) using a statistical method and factorial experimental design method. The main experimental variables were as follows; W/C(4 levels ; 31, 33, 35, 42%), S/a(2 levels ; 55, 58%) and L/C(2 levels ; 5, 15%). The compressive strength and flexural strength of LMC were selected as a factor of response. The statistical method was carried out to analyze the results, together with factorial experimental design method and response surface method. The analysis showed that if L/C had been 15%, W/C appeared to be around 33% to achieve the design strength of 350kgf/cm2. In this case, the flexural strength and the slump came to around 68kgf/cm2 and 18cm, respectively. Eventhough the L/C varied, the design strength and W/C could be predictable together with slump value and flexural strength. As a result of series of experiments in this study, W/C and L/C were proved to be the main factors influencing on the compressive and flexural strength of LMC. Both of strength and slump values could be predictable from the mixing proportion of LMC.

라텍스 개질 콘크리트의 건조수축특성

윤경구,홍창우,이주형 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a same controlled environment of 60% of relative humidity and 20℃ of temperature. Test results revealed that the drying shrinkage of latex modified concrete(LMC), rapid-setting cement latex modified concrete(RSLMC) was considerably lower than that of ordinary portland cement concrete(OPC), rapid-setting cement concrete(RSC), respectively. This may be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic and colloidal properties of the latexes, resulting in reduced water evaporation.

明代 診斷學 發展史에 관한 硏究

이홍구,윤창열 한국한의학연구원 2001 한국한의학연구원논문집 Vol.7 No.1

This report studies the history of diagnostic development of Myeong Dynasty(明代). This period is the success of Keum-Won Dynasty(金元代) when the special development of medicine was taken, and is the origin of the development of medicine of Cheong Dynasty(淸代). The conclusion is like this. The palpitation was developed to be papular, to illustrate and to be simple. The development of seeing diagnostics of Myeong Dynasty was characterized the entrance of special book of seeing diagnostics, the study of finger print of child and the development of seeing tongue diagnostics. In Myeong Dynasty, discrimination of smell theory was developed with the development of fever school. The development of discrimination of symptoms of Myeong Dynasty was finished in every realms, specially in discrimination of symptoms of fever.

유지보수를 위한 RSLMC의 산성 저항성

홍창우,김동호,이훈재,권혁찬,윤경구 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Latex modified concrete is governed by both cement hydration and polymer film formation processes in its binder phase. Such the reactions are expected to improve the polymer-cement co-matrixes themselves and the bond between the cement hydrates and aggregates, and to improve the properties of hardened latex-modified concrete. The purpose of this study was to study the strength and chemical resistance of Rapid-setting latex modified concrete(RSLMC) with the main experimental variables such as latex content(0, 5, 10, 15, 20%) and water-cement ratio(36, 38, 40%) at latex content 15%. Water absorption test was carried out to estimate water permeability resistance. Chemical resistance test was carried out to measure the weight change and to observe the appearance of RSLMC immersion in hydrochloric acid, sulfuric acid, and calcium choloride.

콘크리트가 RC 인장부재의 인장거동에 미치는 영향

홍창우,김남윤,윤경구,이봉학 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

This paper presents evaluation results of the tensile behavior of reinforced high strength concrete. The effects of different sizes of reinforcing bar, ranging from D22 to D29, on the formation of cracks was investigated. Two different strength concretes, 270kg/㎠ and 550kg/㎠, were used in the specimens to investigate the influence if concrete strength on tension stiffening. In the present investigation a method was developed to obtain reliable load-deformation behavior in tension. The experimental results show that (1) high-strength concrete members exhibited larger amounts of tension stiffening than the companion normal-strength concrete members, (2) as the bar diameter increases, the beneficial influence of high-strength concrete on tension stiffening is reduced.

강섬유 보강 콘크리트의 인장강성 및 피로파괴특성

이봉학,윤경구,홍창우,김동호 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

콘크리트의 취성적 성질을 개선하고 부재의 인성을 증가시킨 강섬유보강 콘크리트는 건설분야에 활용할 가치가 크다. 그러나 설계규준이나 해석방법이 정비되지 못한 현 실정에서 거동 특성을 규명하고 이에 유효하고 타당한 해석모델을 제시하는 것이 요구된다. 본 논문에서는 강섬유보강 콘크리트의 강도특성실험, 직접인장실험 및 피로실험을 수행하여 이에 대한 역학적 특성을 고찰하고 거동특성을 규명함으로서 설계와 해석의 기초 자료로 활용하고자 하였다. This study is conducted on the test to find tension stiffening, flexural fatigue characteristics and mechanical properties of steel fiber reinforced concrete. Experimental investigation is examined accord to hooked type fiber contents(0, 0.4 , 0.7, 1.0%), fiber aspect ratio(60.83). The principal results obtain through this study are as follows; steel fiber reinforced concrete is increased completely tensile & flex strength properties compared with normal concrete. The tension stiffening and fatigue life tend considerably increase with fiber contents, fiber aspect ratio.

콘크리트 포장 슬래브의 변형률 측정에 관한 연구

김동호,전성일,최창식,윤병성,윤경구 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

The purpose of this paper is to investigate for strain measurement of concrete pavement slab at field. The early-age behaviors of concrete pavement were measured using the strain gages. From the static and dynamic wheel loading tests, the outputs from each gages were recorded. The measured data, also, was compared to those from finite element analysis. The static wheel loading tests were performed in twice, and the dynamic wheel loading tests were performed at the speed 10㎞∼50㎞. The results could be summarized as follows: To embed the strain gage accurately and stably in concrete pavement, a chair and protective box must be used. The protective box must not be affected from the outside vibrating. From the results of early-age strain measurement, it was found that the strain varied at the maximum value of 180 με. From the results of static wheel loading tests, A1, A2 and B gages generally developed a consistent tendency. When comparing the results from the measured at field and the calculated by FEM analysis, the data of A1 and B gages were similar to that from theory. The values from the field test were generally higher than that from the theory. From the results of dynamic wheel loading tests, it was known that the measured strain at field became smaller as the truck speed became faster, indicating the maximum at the range of 12∼13 με.

한국 폐경 여성에서 호르몬 대체요법시 치료 제제에 따른 유방 치밀도의 변화

이동윤 ( Dong Yun Lee ),김상돈 ( Sang Don Kim ),최영식 ( Young Sik Choi ),지병철 ( Byung Chul Jee ),구승엽 ( Seung Yup Ku ),서창석 ( Chang Suk Suh ),최영민 ( Young Min Choi ),김정구 ( Jung Gu Kim ),문신용 ( Shin Yong Moon ),김석현 대한폐경학회 2003 대한폐경학회지 Vol.9 No.3

목적 : 본 연구는 한국 폐경 여성에서 호르몬 대체요법과 연관된 유방 치밀도의 변화를 평가하기 위하여 시행되었다. 연구 대상 및 방법 : 본 연구에서는 호르몬 대체요법을 시행 받은 폐경 여성 294명을 대상으로 치료 제제에 따라 매일 tibolone 2.5 mg을 투여 받은 군(n=119), conjugated equine estrogen(CEE) 0.625 mg/medroxyprogesterone(MPA) 2.5 mg으로 지속적 병합요법을 시행 받은 군(n=93), CEE 0.625 mg으로 단독요법을 시행 받은 군(n=40) 및 raloxifene 30 mg을 투여 받은 군(n=42)으로 대변하였으며, 호르몬 대체요법을 시행 받지 않은 폐경 여성 36명을 대조군으로 설정하였다. 대상 여성에서 유방촬영술(mammography)을 호르몬 치료 시작 전과 치료 1년 후에 각각 시행한 후 유방 치밀도(breast density)의 변화를 후향적으로 각 군에서 비교 관찰하였다. 결과 : 대상 여성의 연령, 분만력, 폐경 연령, 폐경 후 기간, 체중, 신장 및 체질량지수(BMI)는 각 군간에 통계학적으로 유의한 차이가 없었다. 호르몬 대체요법 1년 후 유방촬영술에서 관찰된 유방 치밀도의 증가는 지속적 병합요법군에서 25.8%(24/93)로서 tibolonerns의 11.8%(14/119), raloxifene군의 2.4%(1/42)에 비하여 각각 유의하게 높았다(p<0.05). 결론 : 본 연구 결과 호르몬 대체요법을 시행 받은 폐경 여성에서 관찰된 유방 치밀도의 변화는 치료 제제에 따라 상이하다는 것을 확인하였으며, 특히 progestogen을 이용한 지속적 병합요법이 유방 치밀도 변화에 중요한 영향을 미치는 것으로 사료된다. Objective : This study was performed to evaluate the mammographic changes in breast density that were associated with hormone replacement therapy(HRT) in Korean postmenopausal women. Materials and Methods : In this retrospective study, 294 postmenopausal women were classified as the four groups according to the regimen of HRT; a daily treatment of tibolone 2.5 mg(n=119), conjugated equine estrogen(CEE) 0.625 mg/medroxyprogeserone(MPA) 2.5 mg(n=93), CEE 0.625 mg only(n=40) or raloxifene 60 mg(n=42), and they were compared with the control group of postmenopausal non-HRT users(n=36). Mammography was performed at baseline and after 1 year of treatment, and the incidence of changes in mammographic density was evaluated and compared among the groups. Results: There were no significant differences in age, parity, age at menopause, years after menopause, weight, height, and body mass index(BMI) among the groups. The risk of an increase in mammographic density after 1 year of treatment was significantly higher in CEE/MPA group(24/93, 25.8%), compared with tibolone(14/119, 11.8%) and raloxifene(1/42, 2.4%) group(p<0.05). Conclusion : This study showed that the changes in mammographic breast density related to postmenopausal HRT were dependent on the regimen of HRT. The continuous administration of progestogen as a component of the combined HRT seems to affect the breast density significantly.

승모판 협착증 환자에서 운동부하 심장풀스캔을 이용한 좌심실기능의 평가

박창윤(Chang Yun Park),이도연(Do Yun Lee),심원흠(Won Heum Shim),김한수(Han Soo Kim),박승정(Seung Jung Park),조승연(Seung Yun Cho),김성순(Sung Soon Kim),이웅구(Woong Ku Lee),김명진(Myeong Jin Kim),최규옥(Kyu Ok Choe) 대한핵의학회 1992 핵의학 분자영상 Vol.26 No.1

N/A We performed exercise radionuclide ventriculography to evaluate left ventricular (LV) function in 35 patients with pure mitral stenosis (MS). There were 6 males and 29 females ranging from 21 to 63 years of age (mean 37±10 years). We also studied 8 healthy men as control group (mean age 27±5 years. Each patients was evaluated at rest and during maximal exercise on an isokinetic bicycle ergometer. Peak filling rate (PFR), peak ejection rate (PER), ejection fracion (EF), end-diastolic volume(EDV), end-systolic volume (ESV), stroke volume (SV), and cardiac output (CO) were determined by the radionuclide technique. The results were summarized as follows: 1) LV systolic dysfunction and reduced PFR were noted in patients with MS. 2) EDV as well as SV decreased with exercise in patients with MS. 3) No significant increase in EF during exercise compared to rest value was observed because it was caused by reduced EDV and SV during exercise in patients with MS. 4) CO increased with exercise was significantly lower than normal in patients with MS. 5) Patients with MS were divided into two groups according to whether EF increased more than 5% druing exercise compared to resting state or decreased. Significant difference were found between these two groups. Patients with a fall in EF with exercise were older, had larger left atrial size, and had lesser decreased in ESV during exercise.