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- 저자 : 김도수(Kim, Do Su) (검색결과 102 건)
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김도수,이철경,박종현,Kim, Do-Su,Lee, Churl-Kyoung,Park, Jong-Hyeon 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.3
본 연구에서는 석탄회로 제조된 인공경량골재에 석회석을 첨가하였을 때 소성온도 및 시간에 따른 소성특성을 관찰하였다. 소성온도의 증가에 따라 quartz($SiO_2$)가 감소한 반면 mullite($3Al_2O_3{\cdot}2SiO_2$)가 증가되었으며, 석회석의 첨가에 의해 clinoptiolite와 pagioclase와 같은 소성에 의한 소성광물이 생성되었다. 석탄회 및 석회석으로 제조된 경량골재의 소성성은 주로 소성시간보다는 소성온도에 의해서 좌우되는 것으로 확인되었다. 또한 소성온도 및 시간의 증가는 골재내 형성된 거대기공의 미세화 및 폐기공의 형성으로 전체 기공부피를 축소시키는 경향을 나타냈다. 1000$^{\circ}$C에서 5분가 소성시킨 경량골재의 표면은 용융 슬래그 층의 융착현상에 의해 개기공이 거의 없었으나 내부는 발포가스에 의해 수 ${\mu}$의 미세기공이 폐기공 형태로 균일하게 분포하였다. 이로부터 석회석이 첨가된 소성 경량골재의 적정 소성조건은 소성온도는 약 1000$^{\circ}$C, 소성시간은 5분이 바람직한 것으로 나타났다. In this study, sintering properties of Artificial Lightweight aggregates(ALAs) prepared from coal ash as a function of sintering temperature (900$^{\circ}$C, 1000$^{\circ}$C, 1100$^{\circ}$C) and time (2min, 5min, 10min) when limestone added as lightweight mineral was investigated. Increasing the sintering temperature resulted simultaneously from a decline of quartz mineral as well as growth of mullite mineral. Addition of limestone to ALAs newly formed sintered minerals such as clinoptilolite and plagioclase. Sintering effect of ALAs prepared from coal ash and limestone was more affected by a sintering temperature than time. As sintering temperature and time increae, transition of macropore to micropore and formation of closed pores were happened, consequently shrank the total pore volume of ALAs. The surface of ALAs sintered at 1000$^{\circ}$C for 5min was nearly not detected open pores due toe amalgamation effect of molten slag layer but homogeneous distributions of closed pores with micro-scale were examined in cross sectional area ALAs. Sintering temperature and time which present the most adequate state, in the preparation of ALAs, are corresponded to 1000$^{\circ}$C and 5min, respectively.
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저농도 HF 수용액을 이용한 Al(OH)<sub>3</sub>의 표면처리
김도수,이철경,양동효,Kim, Do-Su,Lee, Churl-Kyoung,Yang, Dong-Hyo 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.3
Treatment effects of dilute hydrofluoric acid (6 wt% HF) on the surface properties of $Al(OH)_3$ were investigated at the molar ratio of F/Al(fluoride/aluminum)=0.15. Temperature and pH variations in the reaction system were recorded to analyze reaction mechanism between $Al(OH)_3$ and aqueous Hf. The reaction of HF to the surface of $Al(OH)_3$ accompanied with a quantity of heat evolution, resulting in increasing temperature of a reactionsystem. And also the reaction was proceeded as transitional state which metastable ${\alpha}-form\;AlF_3{\cdot}3H_2O$ was transferred to insoluble ${\beta}$-form. The resulting ${\beta}-form\;AlF_3{\cdot}3H_2O$ formed by a surface treatment was identified by FT-IR and X-ray diffractormetry. The formation of ${\beta}$-form aluminum fluoride hydrates with diameter less than $1{\mu}m$ on the surface of $Al(OH)_3$ could be visulaized by SEM imgae, making up a coating layer as precipitate-like. The surface whiteness of $Al(OH)_3$ treated with aqueous HF was furthermore increased approximately 6.6% due to the formation of surface hydrates. 저농도로 희석된 HF 수용액(6 wt%)을 사용하여 $Al(OH)_3$의 표면을 F/Al의 몰비 0.15에서 처리하고, 처리 전후 표면특성을 관찰하였다. 반응계의 온도 및 pH 변화로부터 $Al(OH)_3$에 대한 HF의 표면반응은 HF와 접촉한 $Al(OH)_3$ 표면부에서 metastable한 ${\alpha}$형의 불화알루미늄$({\alpha}-AlF_3{\cdot}3H_2O)$이 안정한 ${\beta}$형의 불화알루미늄$({\beta}-AlF_3{\cdot}3H_2O)$으로 전이되는 과정으로 진행되며, 다량의 발열을 수반하면서 반응계의 온도상승을 유발하였다. 이러한 ${\beta}-AlF_3{\cdot}3H_2O$의 생성은 표면처리된 분말의 FT-IR 및 X-선 회절분석결과를 통해 확인되었다. ${\beta}-AlF_3{\cdot}3H_2O$의 morphology와 분포상태를 SEM을 통해 관찰한 결과 $Al(OH)_3$ 표면에 $1{\mu}m$ 이하의 미세분말 형태로 피복층을 형성하며 균일하게 분포된 것으로 확인되었다. HF로 처리된 시료의 표면 백색도는 미처리에 비해 약 6.6% 증가되었으며, 이는 $Al(OH)_3$보다 높은 백색도를 지닌 ${\beta}-AlF_3{\cdot}3H_2O$ 피복 효과 때문인 것으로 나타났다.
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규불화아연(ZnSiF<sub>6</sub>, aq)이 첨가된 시멘트의 유동성과 수화특성
김도수,길배수,임헌성,남재현,노재성,Kim, Do-Su,Khil, Bae-Su,Lim, Heon-Seong,Nam, Jae-Hyun,Rho, Jae-Seong 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.2
금속염으로 산화아연(ZnO)과 규불화수소산($H_2SiF_6$)을 이용하여 용액법으로 규불화아연($ZnSiF_6$, 농도 15%)을 제조하고 이를 시멘트용 혼화제로 첨가하여 시멘트의 유동성과 수화특성에 미치는 영향을 파악하였다. 규불화아연의 첨가량을 시멘트량 대비 1.0∼4.0%로 증가시켜 첨가한 시멘트 페이스트의 초기 유동성과 유동성의 경시변화를 측정하였다. 초기 유동성은 mini-slump 시험을 통해 평가하였고, 유동성의 경시변화는 slump loss 시험을 통해 평가하였다. 또한 규불화아연을 시멘트에 1.0∼3.0%로 첨가하였을 때 시멘트의 응결시간에 미치는 영향과 시멘트 수화열 변화에 미치는 영향을 파악하였다. 시멘트 페이스트의 유동성은 규불화아연이 2.1% 첨가되었을 때 가장 높게 나타났으나 경시변화는 다소 큰 것으로 나타났다. 시멘트 응결시간은 규불화아연의 첨가량 증가에 따라 지연되는 특성을 보였으며, 시멘트 수화열은 첨가량에 비례하여 감소되는 경향을 보였다. Zinc fluosilicate ($ZnSiF_6$, 15% aqueous solution) was prepared using zinc oxide (ZnO) and fluosilicic acid ($H_2SiF_6$) by soluiton synthetic method. The fluidity and hydration properties of cement which was added $ZnSiF_6$ (aq.) as an additive for cement were studied. At water to cement ratio (W/C) equals to 0.45, the initial fluidity and slump loss of cement paste which the addition of $ZnSiF_6$ (aq.) was increased from 1.0% to 4.0% based on cement weight were investigated. Initial fluidity of cement paste was measured by mini-slump test and slump loss was examined by measuring the fluidity variation of cement paste with time elapsed from 0 min to 120 min at intervals 30 min. Also, the effect of $ZnSiF_6$ addition on the setting and hydration of cement paste when $ZnSiF_6$ increased in the addition range 1.0% to 3.0% were investigated. The fluidity of cement paste which was added 2.1% $ZnSiF_6$ (aq.) presented the highest value among all addition ranges. The setting time of cement paste was retarded gradually and the heat evolution of hydrated cement was reduced with the increasing of $ZnSiF_6$ addition.
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김도수,조현우,김광희,주진규,신윤석,Kim, Dosu,Joh, Hyunwoo,Kim, Gwanghee,Joo, Jinkyu,Shin, Yoonseok 한국건설관리학회 2020 한국건설관리학회 논문집 Vol.21 No.5
건설업은 국내 산업 중 안전사고가 가장 많이 발생한다. 건설업의 재해는 막대한 재산손실과 인명피해로 인한 사회적 문제로 이어지기 때문에 더 각별한 주의를 기울여야 한다. 최근 이로 인해 건설업에서 발생하는 재해에 대한 경각심이 높아지고 있으며 정부 각 부처에서는 안전관리에 관한 규정을 강화하고 있다. 특히 산업안전보건공단에서는 이번 산업안전보건법 전부개정안에서 보호대상의 확대와 책임소재의 명확화에 중점을 두고 있다. 이에 따라 발주자 책임에 의한 안전관리를 중심으로 분석한 연구가 필요한 실정이다. 따라서 본 연구에서는 건설사업관리자의 사업수행능력평가를 산업안전보건법의 전부개정안을 고려하여 안전항목을 고려하여 건설사업관리자를 선정하는 방안을 제시하고자 한다. The construction industry has the most safety accidents among domestic industries. Special care must be taken because disasters in the construction industry lead to social problems caused by huge property losses and casualties. As a result of this, there is a growing awareness of disasters occurring in the construction industry, and government departments are tightening regulations on safety management. In particular, the OSHA (Occupational Safety and Health Agency) focuses on the expansion of protection targets and the clarification of responsibility in the full amendment OSHA. As a result, a study that focuses on safety management by client's responsibility is needed. In this study, the project performance capability assessment of construction project management contractors, which is being carried out with uniform assessment criteria without considering the characteristics of the construction project, is considered and all the amendments to the OSHA are considered, and the factors were derived for improvement measures.
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10주간의 유산소운동과 무산소운동이 남자 초등학생의 성장인자에 미치는 영향
김동희(Dong Hee Kim),김유섭(Yoo Sub Kim),이하얀(Ha Yan Lee),김회원(Hoe Won Kim),신세훈(Se Hoon Shin),장선웅(Seon Woong Jang),김도수(Do Soo Kim) 한국사회체육학회 2007 한국사회체육학회지 Vol.0 No.31
The purpose of this study was to investigate the effects of aerobic exercise and resistance exercise on the growth relation factor. The subjects for this study were forty two elementary male students and divided into 3 groups: aerobic exercise(running) group(N=14), resistance exercise(dumbbell) group(N=14), and control group(N=14). The aerobic exercise group performed running 40 min in a bout, four times a week at the intensity of 50~60%HRmax(1~5 weeks; 50~60%HRmax, 6~10 weeks; 61~70%HRmax). The resistance exercise group performed dumbbell exercise consisting of 12 factors using 1~2㎏ weight(1~5 weeks; 1㎏, 6~10 weeks; 2㎏). And the change of growth relation factors such as growth hormone(GH), insulin like growth factor-1(IGF-1) have been measured before, by post exercise 10 weeks respectively. Statistical techniques for data analysis were ANCOVA to determine the difference between exercise duration(10 weeks) and the difference between the aerobic exercise group and the resistance exercise group. The 5% level of significance was utilized as the critical level for acceptance of hypotheses for the study. The following results were obtained from this study. 1. The change of growth relation factors(GH, IGF-1) in the aerobic exercise group and the resistance exercise group were increased significantly after 10 weeks of exercise. That is, blood lipids such as GH(2.07ng/㎖, p<.01; 2.36ng/㎖, p<.01) and IGF-1(40.42ng/㎖, p<.01; 48.93ng/㎖, p<.01) were increased significantly after 10 weeks respectively, but there was no significant difference between the two groups. These results suggest that both aerobic exercise and resistance exercise for 10 weeks affect growth relation factors in elementary male students. Therefore, resistance exercise using dumbbell exercise as well as aerobic exercise was available for normal growth and development. Children, unlike most adults, naturally engage in spontaneous, vigorous physical activity. Since exercise in children is an essential biological process and likely plays an important role in normal growth and development.
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