콘크리트 포장의 플라이애쉬 재활용 방안연구

정영화,최성용,윤경구,용석응,김태경 강원대학교 석재복합신소재제품연구센터 1998 석재연 논문집 Vol.3 No.-

한국 대부분의 고속도로는 콘크리트로 포장되고 있으며, 플라이애쉬를 포장용 콘크리트에서 재활용하면 콘크리트의 성능을 향상시킴과 동시에 경제적 이익과 환경보호에 큰 기여를 할 것이다. 본 연구에서는 플라이애쉬를 포장 콘크리트에 재활용하고자, 플라이애쉬 치환율, 물-시멘트비, 굵은골재 최대치수를 주요실험 변수로 하여 이들이 플라이애쉬를 혼입한 포장용 콘크리트의 역학적 특성에 미치는 영향을 살피기 위해서 실험하여 통계처리 분석하였다. 이러한 분석결과를 바탕으로 포장 콘크리트의 적정배합을 제시하였으며 결과는 다음과 같다. 플라이애쉬를 혼입한 포장콘크리트의 휨강도에 영향을 미치는 인자는 플라이애쉬 치환율이 가장 큰 것으로 나타났으며, 다음으로 굵은골재 최대치수와 물-시멘트비 순으로 영향을 미친다. 또한, 플라이애쉬 치환율과 굵은골재 최대치수의 상관관계가 가장 큰 것을 알 수 있었다. 목표압축강도를 목표 휨강도의 6배로 선택하여 적정구간을 결정하였으나, 적정배합구간이 목표압축강도에 의해서 결정되었다. 이는 플라이애쉬의 작은 수화물이 공극을 효과적으로 채움으로써 휨강도의 증진에 크게 기여하기 때문으로 판단된다. 고속도로 포장에 적용할 수 있는 32mm의 굵은골재 최대치수와 45%의 물-시멘트비를 사용하는 목표 휨강도 45kg/㎠의 적정배합에서는 5.0%까지 플라이애쉬를 치환 가능하고, 50kg/㎠의 적정배합에서는 2.5%까지 치환 가능하다. 공항 포장에 적용할 수 있는 40mm의 굵은골재 최대치수와 37%의 물-시멘트비를 사용하는 목표 휨강도 45kg/㎠의 적정배합에서는 4.5%까지 플라이애쉬를 치환 가능하고, 50kg/㎠의 적정배합에서는 2.0%까지 치환 가능하다. The most of highway in Korea have been paved by concrete since last ten years. The recycling of fly ash in pavement concrete may result in economics, the improvement of concrete quality and the reservation of environment. This paper focused on the series of experiment and statistics analysis with experimental variables such as fly ash substitute ratio, water-cement ratio and maximum size of coarse aggregate in order to investigate the feasibility of recycling of fly ash in pavement concrete, to see the strength characteristics and t propose the optimum mix design based on previous results. The results of experiments and analysis were follows; The fly ash substitute ratio affected most seriously to the flexural strength of concrete among main variables, followed by maximum size of coarse aggregate and water-cement ratio. The interaction between fly ash substitute ratio and coarse aggregate size was the biggest. The optimum mix design was determined by target compressive, which was selected as 6 times of flexural strength. This indicated that the small hydrate of fly ash in concrete filled in effectively and resulted in the enhancement of flexural strength. the optimum mix design for highway pavement concrete with 32mm of maximum size of coarse aggregate and 45% of W/C can incorporate up to 5.0% and 2.5% of fly-ash at 45 kg/cm² and 50 kg/cm² of target flexural strength, respectively. The optimum mix design for airport pavement concrete with 40mm of maximum size of coarse aggregate and 37% of W/C can incorporate up to 4.5% and 2.0% of fly ash at 45 kg/cm² and 50 kg/cm² of target flexural strength, respectively.

담양신설 IC의 교통소음도 조사연구

최형일,강영주,채희정,김연풍,조도호,설동화,정숙경 조선대학교 환경공해연구소 2007 環境公害硏究 Vol.20 No.1

After the vehicle has become a large formation with high-speed, loud noise from an express highway is increasing, and the number of large-scale apartment complexes, which are recently being constructed in the metropolitan area nearby the express highway and IC, is increasing gradually. Compared with a main road, the traffic volume and the speed of a vehicle between IC and the ramp way [turn-off] are smaller. If the ramp way is rightly connected with the downtown area, however, the traffic-noise that comes about in surrounding areas will be in conjunction with the traffic-noise from the main road of express highway and that of the ramp way. This research has selected a place that hasn't had a road or a commercial quarter nearby the main-road of IC and ramp way. Then we have studied the traffic-noise status under minimizing influence of its outer-noise, which occurs in IC. 1. The traffic volume change of a small and full-sized car with time has been kept on regularity in 2004 and 2005. As the traffic volume of a full-sized car has diminished remarkably, it has been maintaining through 6:00a.m.-10:00 a.m. As it has decreased since lO:OO a.m.. we have also observed the traffic proportion going up. 2. Monthly traffic volume of small cars was higher in May, August and October than other months. We have observed that the high traffic volume during these months is due to the following: May-The Damyang festival, August-a high-demand season, October-viewing scarlet maple leaves. Monthly traffic volume of full-sized cars was generally higher in August, but it has decreased during 2006. This was due to the many construction trucks that were working on the extension of the 88 Olympic expressway. Therefore, there was more traffic volume in 2006 compared to 2004 and 2005. 3. In this study, the noise figures have been less than 55 dB(A) in 18 spots. There were 14 spots from 55dB(A) to 58dB(A). 58-61dB(A) : 20, 61-64dB(A) : 17, 64-67dB(A) : 18. There were 8 spots we observed at the highest level from 67dB(A) to 70dB(A). Those were the nearby spots separating the main road and Damyang IC. 4. Traffic-noise at the boundary between IC and the main road of an expressway was higher than that of the same distance in other places. 5. We have observed that traffic-noise is low in places with mountains that serve the role of soundproofing walls. Thus, the fundamental sound hadn't affected it.

충남대학교병원 마취발전의 경향에 관한 분석 : 1967년부터 - 1996년까지 from 1967 to 1996

최세진,김상수,정규돈,윤석화,신용섭,손수창,이원형,김혜자,이정은 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.2

To evaluate the specificity and historical trends of the anesthesia in Chungnam National University Hospital, anesthetic experiences of 83,572 in total performed at Chungnam National University Hospital from January 1967 to December 1996 were analyzed statistically and clinically according to age, sex, surgical department, physical status, elective and emergency surgery, premedicants, IV anesthetics, anesthetic methods, inhalational anesthetics, muscle relaxants. The results were as follows : 1. The number of cases has been steadily increased year by year. 2. The ratio of male to female was 52.8% : 47.2%. 3. According to the age, There were 44,905 cases (54%) in the group of 13-45 years. 4. According to the ASA classification of physical status, most of the cases were belonged to the class 1 & 2 (72.5%). 5. The ratio of elective to emergency was 79.4% to 20.6%. 6. Recently, glycopyrrolate has been used increasingly. 7. Thiopental sodium has been mainly used for intravenous induction agent. 8. General anesthesia has been used mainly. 9. Enflurane is the most common inhalational anesthetic agent. but Isoflurane has been used increasingly. 10. Most of muscle relaxants are Pancuronium & Vecuronium(84.5%).

素月과 萬海 -그 同質性과 異質性-

崔正錫 대구효성가톨릭대학교 1970 연구논문집 Vol.6 No.1

그람양성구균에 대한 Teicoplanin과 Vancomycin의 시험관내 항균력

최태열,김경숙,전용관,서일혜,김정욱,이웅수,안정열,김홍석,정재용,최효선,김덕언,유진우 대한감염학회 1994 감염 Vol.26 No.1

An increasing frequency of methicillin resistant S. aureus(MRSA), methicillin resistant coagulase negative staphylococci(MRCNS) and Enterococcal infection have been observed in recent years. Teicoplanin is a new glycopeptide antibiotic obstained from the Actinoplanes teicomycetius. The molecular structure and spectrum of antimicrobial activity of teicoplanin is simillar to those of vancomycin, and has been reported to have an excellent in vitro and in vivo effect against various gram-positive infections. Therefore, we evaluated the in vitor susceptibility of gram positive cocci, such as, S. aureus, coagulase negative Staphylococci(CNS), and Enterococci to teicoplanin and vancomycin. The total 253 strains consisted of MSSA(40), MRSA(53), MSCNS(47), MRCNS(48), and Enterococci(65). They were assayed by disc diffusion and agar dilution. During the study, 57% of S. aureus and 49% of CNS showed resistance to methicillin. The inhibitory diameter of teicoplanin was 15-20mm in MSSA, 12-19mm in MRSA, 13-24mm in MSCNS, 11-23mm in MRCNS, and 15-22mm in Enterococci respectively, and showed sensitivity in all but 8 strains(3.2%). The range of the minimum inhibitory concentration (MIC) of teicoplanin to MSSA, MRSA, MSCNS, MRCNS and Enterococci were 9.12-2.0㎍/ml, 0.25-2.0㎍/ml, & 0.25-32㎍/ml, 0.12-1.0㎍/ml respectively. One case of S. haemolyticus was resistant to teicoplanin (32㎍/ml) by the agar dilution method. Eight minor (3.2%) and one major(0.4%) error was observed when the MIC and disk diffusion data were correlated with teicoplanin. As for vancomycin the inhibitory diameter was 17-21mm in MSSA, 15-21mm in MRSA, 18-26mm in MSCNS, 18-25mm in MRCNS, and 16-22mm in Enterococci respectively. The range of the MIC of vancomycin to MSSA, MRSA, MSCNS, MRCNS, and Enterococci were 0.25-1.0㎍/ml, 0.25-4.0㎍/ml, 0.5-2.0㎍/ml and 0.5-2.0㎍/ml respectively. One minor error (0.4%) was seen with the vancomycin disk. The MIC90 of MSSA and MRSA exhibited the same results in teicoplanin (1.0㎍/ml, 1.0㎍/ml), and vancomycin(2.0㎍/ml, 2.0㎍/ml). MSCNS and MRCNS exhibited greater MIC90 with teicoplanin(4.0㎍/ml, 8.0㎍/ml) than vancomycin(2.0㎍/ml, 2.0㎍/ml). Incontrase Enterococci were more susceptible to teicoplanin(0.5㎍/ml) than to vancomucin (2.0㎍/ml). Results from this analysis indicated that both teicoplanin and vancomycin were very excellent for gram positive infections, especially those resistant to methicillin.

하악 제1대구치의 치근 만곡에 영향을 주는 요인

최항문,이원진,허민석,이삼선,김정화,최순철,박태원 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Materials and Methods : Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal plane angle, gonial angle, and gonion-gnathion distance (Go-Gn distance) were measured. In panoramic radio graph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. Results : The Pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p<0.05). There was no significant correlation between elongated root length and longitudinal variations of all variables. The resulting regression equation was Y=10.209+0.208X_(1)+0.745X_(2) (Y: root angle, X_(1): variation of occlusal plane-tooth axis angle, X_(2): variation of ramus-occlusal plane angle). Conclusion: It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane. (Korean J Oral Maxillofac Radiol 2006; 36 : 55-62)

복수의 자율이동로봇의 협조운동에 관한 연구

정원갑,최유식,서호철,이석규,이달해 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2

This paper proposes a fuzzy algorithm for cooperative behaviors of multiple autonomous mobile robots. Each robot makes decision of his behavior based on the information obtained by ultrasonic sensors to measure the position and angles of other robots. To enhance the industrial applicability of the suggested algorithm, we add disturbances of error angle caused by wheel steering when autonomous mobile robot navigates toward next destination point. This algorithm uses the position and velocity information of both the nearest robot and other robots within the detective radius of sensor with different weighting. Based on the fuzzy rule table and fuzzy inference, we obtain the rotational angle of the robots. The effectiveness of the proposed algorithm is shown by some computer simulations where a group of mobile robots encircles with equi-interval. In addition each robots is given weighting value to avoid the wall. Finally, the suggested algorithm shows that the more robots exist, the more effective it is.

한글과 韓國文學 (一) : (1) 前代文學

崔正錫 대구효성가톨릭대학교 1972 연구논문집 Vol.10 No.1

TERUDERMIS를 이용한 골 혹은 건이 노출된 창상의 치료

최민호,이상복,황정욱,양완석,이강길 大韓成形外科學會 1999 Archives of Plastic Surgery Vol.26 No.3

Deep skin and soft tissue defects with exposed bone and tendon is difficult to treat, because skin graft rarely survives and flap surgery is sacrifice of donor site. Since "Stage I" membrane was developed by Yannas and Bruke in 1980, numerous kinds of artificial skin have been developed. The adaptability of "Terudermis", developed by the Terumo Co., as an artificial skin composed of sponge made of a fibrillar atelocollagen and a heat-denatured atelocollagen, was clinically evaluated on application to 13 cases presenting deep skin and soft tissue defect with exposed bones and tendons from October 1997 to march 1998. Terudermis has the advantage of allowing early incorporation of fibroblasts and capillaries into its collagen sponge due to very weak dehydrothermal cross-linking. Before Terudermis graft, several days of wet dressing and debridement were required to prepare healthy well- vascularized bed because Terudermis was weak on unsanitary wounds. After bed preparation, Terudermis was grafted like usual skin graft. Tie-over bolster dressing or compressive dressing was used case by case. The dressing was opened 2~3 days after Terudermis grafting. Wet dressing was done daily until the skin graft was done. Autologous skin graft was done 2∼3 weeks after Terudermis graft. Our clinical results indicated that Terudermis was beneficial in treating 77% of our patients. Through the use of this new method, treatment of severe skin and soft tissue defects that are usually treated by musculocutaneous or other conventional skin flaps can be replaced by Terudermis as an new artificial dermis.

치아경조직 부식후 재경화에 관한 실험적 연구

최유진,홍정표,한봉석 慶熙大學校 齒科大學 1989 慶熙齒大論文集 Vol.11 No.-

This study was performed for the purpose of examining the effects of aqueous solution of sodium fluoride on the reminerali7ation and rehardening of human tooth enamel. 16 pairs of permanent first premolars extracted from Korean were tested. Microhardness test and scanning electron microscopy were investigated on sound enamel, initial carious enamel, enamel treated with sodium fluoride after etched with 30% phosphoric acid and initial carious enamel treated with sodium fluoride, respectively. The results obtained were as follows: 1. The microhardness value of sound enamel surface was Hv. 347-391, and the mean was Hv 367.2. 2. The initial carious enamel surface treated with 2% sodium fluoride solution has shown dense appearance in SEM, but the increase of microhardness value was not remarkable. 3. Enamel surface etched with phosphoric acid and then treated with 2% NaF solution was changed to relatively dense structure in SEM, but the microhardness value was only Hv. 238.2. 4. The mean microhardness value was highest in sound enamel (Hv. 367.2) and followed by fluoride solution-treated initial carious enamel (Hv. 293.0), initial carious enamel (Hv. 291.3) and fluoride solution-treated etched enamel (Hv. 238.2) in order. 5. The microhardness value of the substance formed initially on the carious or etched enamel surface by application of 2% NaF solution was very low.