저온에서의 콘크리트 강도 확보를 위한 경제적 배합 방안

김상철,김용직,김영진,Kim, Sang-Chel,Kim, Yong-Jic,Kim, Young-Jin 한국건설순환자원학회 2012 한국건설순환자원학회지 Vol.7 No.4

프리캐스트 콘크리트 공법은 건식공법으로서 현장에서의 작업량을 최소화할 수 있으며 품질관리가 쉽고, 조립으로 공기단축이 가능하지만, 공기상 조기에 콘크리트 강도를 확보하기 위하여 콘크리트의 강도발현속도를 촉진시키는 증기양생법에 의존하여 왔다. 그러나 최근에 나타나고 있는 중동에서의 정치적 불안이나 국제 경제의 불안정으로 인해 지속적으로 유류비는 상승되고 있다. 따라서 본 연구에서는 프리스트레스트용 프리캐스트 콘크리트 제품 생산을 위해 저온의 조건에서 증기양생을 사용하지 않고 1일 압축강도 14MPa 이상, 설계기준압축강도 40MPa를 확보하는 콘크리트 개발을 목표로 하였다. 1종 포틀랜드시멘트와 3종 조강포틀랜드시멘트, 특수목적의 조강혼합시멘트 등 3종류의 시멘트에 대해 굳지 않은 콘크리트의 물성과 압축강도를 실험을 통해 평가하였다. 실험결과, 조강용 시멘트들은 슬럼프와 슬럼프경시변화, 공기량 확보 측면에서 불리하였지만 강도 측면에서는 목표값 이상을 확보하였으며 특히, 조강혼합시멘트가 가장 우수한 것으로 나타났다. Precast concrete method is known to have advantages of minimizing works in the construction, controlling concrete quality easily and saving construction period due to only fabrication work in the construction field, but it needs to apply steam curing to accelerate early concrete strength. In the meanwhile, the oil cost for steam curing has been continuously increased because of political instability in the middle East and international economic shaky. Thus, this study addresses the development of precast/ prestressed concrete which has over 14MPa at 1 day age and specified concrete strength of 40MPa at low temperature, not applying steam curing. Tests were carried out in terms of material characteristics in fresh concrete and compressive strength using 3 types of cement such as Type I, Type III and rapid hardening compound cement. As results of tests, it is found that cements for rapid hardening had disadvantages with respect to slump, slump loss, and air content, but showed higher compressive strength than specified one, especially the highest value when using rapid hardening compound.

동시 스퍼터링법에 이용하여 제작한 TiO₂와 Ag/TiO₂ 광학 박막의 특성

김상철,한성홍,김의정,이충우,주종현,김구철,Kim, Sang-Cheol,Hahn, Sung-Hong,Kim, Eui-Jung,Lee, Chung-Woo,Joo, Jong-Hyun,Kim, Goo-Cheol 한국광학회 2005 한국광학회지 Vol.16 No.2

고주파 마그네트론 동시 스퍼터링법을 이용하여 $TiO_2$ 박막에 Ag를 도핑한 $Ag/TiO_2$ 박막을 제작하고, 열처리 온도에 따른 박막의 물리적, 화학적 특성을 조사하였다. XRD 측정 결과로부터 금속을 도핑한 박막이 순수 $TiO_2$ 박막보다 결정크기가 더 작은 것을 확인하였으며, SEM 측정 결과로부터 $Ag/TiO_2$ 박막은 순수 $TiO_2$ 박막보다 골자의 크기가 작고 균일하다는 것을 알 수 있었다. 제작된 박막은 가시광선 영역에서 높은 투과율을 나타내었다. $600^{\circ}C$에서 열처리한 박막은 아나타제 결정상이 나타났으며, $900^{\circ}C$에서 열처리한 박막은 아나타제와 루타일상이 혼합되어 나타났다 특히, $900^{\circ}C$에서 열처리한 경우 아나타제에서 루타일로의 상전이에 따른 밴드갭 에너지의 변화에 의해 박막의 흡수단이 장파장 영역으로 이동하였다. 또한 박막 내의 흡수와 산란효과에 의해 투과율이 감소하였다. $Ag/TiO_2$ 박막의 광활성은 순수 $TiO_2$ 박막보다 우수함을 알 수 있었다. Ag-doped $TiO_2$ thin films were prepared by RF magnetron co-sputtering method, and their physical and chemical properties were examined as a function of calcination temperature. XRD results showed that the crystallite size of Ag-doped films was smaller than that of the $TiO_2$ thin films. SEM results showed that the particle size of $Ag/TiO_2$ film was smaller and more uniform than pure $TiO_2$ film. The films had high transparency in the visible range. The films calcined at $600^{\circ}C$ were the anatase phase, and the films calcined at $900^{\circ}C$ were a mixture of anatase and rutile phases. The absorption edge of films calcined at $900^{\circ}C$ was red-shifted. This is due to the augmented absorption resulting from the phase transformation from anatase to rutile phase. And the transmittance of films decreased by the light scattering and absorption in the films. Photocatalytic activity of $Ag/TiO_2$ thin films was higher than that of the pure $TiO_2$ thin films.

Disciplinary Session 2 / Sport History / Cultural and Historical Overview of Sport and Physical Education : 한국 무도의 문화적 이해

김상철,허건식,박범남 ( Sang Chul Kim,Keon Sik Heo,Beom Nam Park ) 한국체육학회 1998 국제스포츠과학 학술대회 Vol.1998 No.1

대형시공사의 사업관리 역량 강화를 위한 교육 전략 수립에 관한 연구

김상철,박찬정,이상엽,손재호,Kim, Sang-Chul,Park, Chan-Jeong,Lee, Sang-Youb,Son, Jae-Ho 한국건설관리학회 2007 건설관리 : 한국건설관리학회 학회지 Vol.8 No.5

It is related to launch the CM market and to increase the profit and entire ability in company that is enforcing the ability of construction management in large-scaled construction company. According to the CM market in U.S, CM market is increased with competing to the companies, that is E&C, general contractor, design firm, specialized CM firm. Also domestic market is similar to US market. In this situation, large-scaled construction companies are filled with construction management ability for competing with foreign companies and domestic CM firms. This paper suggests how to enforce the construction management ability through education, and shows the detailed education strategy considered the fields, divisions and positions. 대형시공회사에 있어 CM 역량강화의 문제는 비단 CM 시장의 진출뿐만 아니라 회사의 역량 강화, 경쟁자와의 차별성 및 수익성의 증대라는 측면에서 대단히 중요한 의미를 갖는다. 현재 미국의 CM시장을 분석하여 본 결과 CM은 EC, GC, 그리고 설계 및 전문 CM사와의 각축속에서 그 규모가 점차 확대되고 있고, 국내의 경우의 경우도 그와 유사하게 진행되어가고 있다. 이러한 상황에 대형시공사는 국내시장에서 기존의 CM 강자들과의 경쟁과 해외시장에서 선진 외국사와의 경쟁을 위해서는 부족한 CM 역량에 대한 시급한 보완이 필요하다고 판단된다. 이에 본 논문은 CM 역량 강화를 위한 교육 전략 수립에 초점을 맞추어 연구를 진행하였고, 각 현장, 사업본부, 직급을 고려한 교육 전략을 제시하였다.

헬리콥터 비행 시뮬레이터와 실 비행훈련과의 효과 분석: 계기비행 훈련을 중심으로

김상철,김종민,Kim, Sang-chul,Kim, Jong-min 한국항공운항학회 2020 한국항공운항학회지 Vol.28 No.1

To compare and analyze the differences between flight simulation and actual flight among 130 army helicopter pilot training subjects, the correlation analysis was performed first through t-testing and multiple regression analysis of individual characteristics and flight simulation and actual instrument flight training, which were analyzed significantly in the age (a3) and service classification (a5) of the six verification factors. This has been shown to be significant, with no difference between the flight simulator and the actual flight. Second, in order to study the correlation between aircraft types, the flight evaluation (v1) was analyzed as a dependent variable for the performance of the flight simulator (KUH: s2, UH60: s3, AH-1S: s5, UH-1H: s6), and the results of the multiple regression analysis of the flight simulator evaluation (s1) were analyzed, in contrast, as a dependent variable, and in conclusion, the training of the flight simulator provided statistical data on the possibility of replacing the actual flight training, which is thought to contribute to the orientation, budget reduction and aviation safety of the pilot training.

공동주택의 실내공기질 관리 - 주방에서의 조리 시 발생하는 유해물질

김상철,Kim, Sang-Cheol 한국공기청정협회 2016 空氣淸淨技術 Vol.29 No.1

시멘트 혼합토의 강도 특성

김상철,이상호,Kim, Sang-Chul,Lee, Sang-Ho 한국농공학회 2005 한국농공학회논문집 Vol.47 No.3

This study was conducted by the tests of materials engineering and soil mechanics to see the strength characteristics of the ‘Cement-Mixed Soil'. To sum up my experiments, I would like to present the results which are the theoretical base and fundamental data to establish the standard design including the design of mixing proportions of the soil as a construction material. In conclusion, in this study the optimum cement mixing ratio is $9\%$ and in this ratio the optimum moisture content of compaction work is $19.3\%$ from the analysis of the strength characteristics, as well as in consideration of the economic profits and nature familiar facts.

흡연과 공기청정 - 흡연부스 시험 및 평가 방법

김상철,Kim, Sang-Cheol 한국공기청정협회 2015 空氣淸淨技術 Vol.28 No.2

젖소 번식장애(繁殖障碍)의 발생현황(發生現況) 및 치료후(治療後) 수태율(受胎率)에 관한 조사연구(調査硏究)

김상철,조충호,이광원,Kim, Sang-cheol,Jo, Choong-ho,Lee, Kwang-won 대한수의학회 1986 大韓獸醫學會誌 Vol.26 No.1

The 587 Holstein cows which calved from January 1983 to December 1984 at an integrated dairy farm in Chung-nom province were examined for the incidence of reproductive disorders and their conception rate after treatment. The results obtained were as follows; 1. The incidence of reproductive disorders was 47.9% (281 heads) among 587 heads which calved. 1) As number of calvings increased, the incidence of reproductive disorders decreased. 2) The cows which calved in spring and summer showed significantly higher incidence of reproductive disorders than those which calved in autumn and winter (p<0.05). 3) Among reproductive disorders, ovarian, uterine, cervical and vaginal diseases figured 54.3%, 43.7%, 0.9% and 0.6%, respectively. 4) Among individual genital diseases, endometritis (40.3%) occurred most frequently. 2. Among 281 heads with reproductive disorders, 216 heads(76.9%) conceived after treatment. 1) After treatment of reproductive disorders, the conception rate by number of calvings was in range from 69.6% to 87.5%. 2) The cows which calved in summer and winter showed significantly higher conception rate after treatment of reproductive disorders than those which calved in spring and autumn (P<0.05). 3) The conception rates after treatment of the cows with ovarian, uterine, cervical and vaginal diseases were 66.5%, 81.2%, 33.3% and 50.0% respectively. 4) The cows with endometritis showed the highest conception rate after treatment (85.9%).

[초청논문] Track 1 : CEM 실무사례 CME Industrial Session

김상철,Kim, Sang-Cheol 한국건설관리학회 2009 한국건설관리학회 논문집 Vol.10 No.6