실리카흄을 흔입한 고강도 콘크리트 개발

홍창우,김태경,김경진,김성환,김남윤,심도식,이정호,윤청호,백민경,원치문,박제선,이주형,정경일 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-

콘크리트 구조물이 대형화됨에 따라 설계단면이 증대되어 상대적으로 많은 경제적 손실을 부담하게 된다. 따라서 단면을 감소시키면서도 소요의 하중에 안전한 구조물을 건설하기 위해서는 우선적으로 구조물 건설에 기초가 되는 고품질, 고내구성의 고강도 콘크리트 개발이 절실히 요구된다 본 연구에서는 일정 시멘트비 및 혼화재 비율하에서 소요의 워커빌리티가 확보되는 고강도 콘크리트를 시간과 온도의 변화에 따라 증기 양생하여, 압축, 인장, 휨강도 뿐만 아니라 파괴특성을 실험적으로 연구하였다. 시료 제작시 시멘트 입자 사이의 공극 및 불연속 영역을 충전하여 고밀도화하기 위한 콘크리트용 혼화재로 시멘트 비표면적이 상당히 작은 초미립 분말인 실리카흄을 이용하였다. 또한 AE감수제 및 고성능 유동화제를 사용하여 혼화재의 첨가에 의하여 발생될 수 있는 워커빌리티의 감소를 방지하였다. 실험결과에 의하면 일정 양생 지속 시간하에서 온도의 증가에 따라 콘크리트의 압축, 인장 및 휨강도가 전반적으로 증가하였다. 동일하게 일정 온도하에서 양생 지속시간이 커짐에 따라 강도들이 증가됨을 알 수 있었다. 따라서 상대적으로 높은 온도와 긴 지속 양생 조건하에서 파괴에 대한 저항력이 크게 나타났다. The compressible, tensible, and flexibleresistance of the high strength concrete is analyzed by the experimentation in the present study. For the test, we cure several samples with the silica fume as a mixture being become dense the spaces between the particle of cement under the variation of both the temperature and the curing-interval. Then, the superplasticizer and the ezcon are also used to satisfy the required workability for construction. The compressible, tensible, and flexible resistances to a stress are increased as increasing the temperature and the time interval for the curing. Therefore it is concluded that the overal fractural and mechanical properties is improved by mixing the silica fume into the cement.

치은섬유모세포 및 치주인대세포에 의한 교원질 수축에 관한 연구

홍영안,김현수,주성숙,신제원 慶熙大學校 齒科大學 1995 慶熙齒大論文集 Vol.17 No.2

The purpose of this in vitro study was to evaluate contraction of the human gingival and periodontal ligament fibroblast in the collagen matrix. The cell cultures were prepared using human gingiva and tooth. The collagen gels were observed daily with an inverted microscope and their area was determined by measuring the diameters of the collagen gel. The configurations of human gingival and periodontal ligament fibroblasts were done by SEM observation. The results as follows; 1. The contraction was found to be proportional to seeding cell without seeding cells, the contraction was not occured. 2. Periodontal ligament fibroblast was shown more fast contraction than gingival fibroblast. 3. The collagen matrix was translucent initially, but with fully contraction, the structure become opaque. 4. The collagen matrix with fibroblast were aggregated to form bundles and reorganized collagen fiber.

中學校 科學 敎科書의 比較分析 : 中學校 Ⅱ學年 科學 敎科書를 中心으로

洪春杓,吳濟植,金鎭彦 공주대학교 사범대학 과학교육연구소 1990 과학교육연구 Vol.22 No.1

Recently science curriculum in middle school was reformed the fifth and the science textbook of middle school is five species. In order to prompte educational effect, this study compared and analyzed five kinds of new science textbook with an old science textbook of the second year in middle school The results of this study can be summarized as follows. 1) Reformed five kinds of science textbook have various contents by participating 50 authors 2) Reformed science textbook increased 10 pages more than old science textbook of middle school in quantity. 3) It was found out that the numbers of the "Study and Observation" and "Exercises and Questions" in new science textbooks increased. 4) The numbers of Pictures were unchanged and the numbers of Tables. Experiments, Exercises and Composite Questions were decreased. 5) The 38∼42% was appeared the ratio of Experiments, Tables, Pictures, and Goethic type Terms in more than three kinds of science textbooks. 6) New science textbooks were reflected 61∼75% of an old science textbooks in Pictures, Goethic type Terms, Tables, and Experiments. As these results Terms and Contents reprented by Goethic type in science textbook should be selected carefully in order to prompte educational effect. The selection of Exercises, Composite Questions, Experiments and Observations should be allocated equally to each unit and behavior area. And this study suggests that there should be introduced experiments of an environment pollusion and its influence into a science textbook.

CIM시스템 評價 要因分析에 관한 硏究

김제홍 건국대학교 1995 대학원 학술논문집 Vol.40 No.-

This paper analyzed the evaluating factor for introducing CIM System which is gradually required from the growing competition and higher business speed. It may not approprivate for traditional methods to that because they required only quantative evaluating and excessive measuring. In this sence if may be proper method to unify the quantative method by description or checklist and Semiquantative method using relative evaluating index. As Production system satisfied different standard for products, standard flexibility is nowday more important than quantative flexibility.

조직적스포츠참가가 스포츠태도에 미치는 영향

김규수,이재홍 龍仁大學校 1991 용인대학교 논문집 Vol.7 No.-

The purpose of this study was to compare differences on the sport attitude between athletes and non-athletes among middle school students. Data collected from a questionnaire designed for this study consisted of foreed-choice response to item constructed to represent the operational definitions for each variable. The inventory was administered to 322 athlete(male : 174, female : 148) and 431 non-athletes(male : 218, female : 213) among middle school student in Seoul. To data analysis, statistics employed this study was t-test. Based upon the result of this study, the following conclusion appear warranted. 1. In cases of attitudes on the sparing of time and money, fostering simple thinking and selfish, strengthening the violence, increascing the reasonable competition, strengthening the mental fitness, and cultivating the discipline compared to non-athletes, while non-athletes are more positive than athletes in attitude toward character buliding. 2. Athletes participating in dual sports are more negative than that in individual sports in strengthening the violence, but in the cases of attitudes on the sparing of time and money, fostering simple thinking and selfish, nationalism, strengthening the violence, character building, increaseing the reasonable competition, strengthening the mental fitness, and cultivating the discipline.

CIM 시스템의 경제성 평가에 관한 연구

김제홍 건국대학교 1996 대학원 학술논문집 Vol.43 No.-

The investment of CIM(Computer Integrated Manufacturing) will be reasonably selected according to the knowledge of each effective factor. Determination of configuration and selection of the management investment to be considered is very importent issue in the CIM. The property of CIM is classified into quality, reliability, flexibility and productivity. The object matrices are used for evaluation of each factor. In general, the evaluation of CIM is either quantitative or qualitative. The former has the limitation by a factor of being hard a measure for data and the latter has a shortcoming of being impossible to gain an objective judgement. Moreover, proper measurement of each factor is not easy because its scale and expective effect are so bulky. This study is concerned with the economy of the CIM. Therefore this study presents the method for evaluation in the case when the attribute is either quantitative or qualtative.

지리정보시스템을 이용한 도시지역 유출수문곡선 해석

조홍제,김정식 울산대학교 1999 공학연구논문집 Vol.30 No.1

지리정보시스템(Geographic Information System)을 이용하여 도시하천유역을 격자로 구성한 후 강우로 인한 지표면 흐름을 운동파해석으로 유출을 모의하였고 적용성을 검토하였다. 국립지리원에서 1:5000 수치지도로 제작된 유역면적 125.4km², 유로연장 23.4㎞인 사연제 유역을 대상지역으로 선정하였고 GIS Tool인 Arc/Info를 활용하여 본 유출모형에 필요한 지형인자를 추출하였다. 그리고 Arc/Info의 모듈인 GRID를 사용하여 수지지도를 100m100m 의 DEM (Digital Elevation Model)자료로 변환하였고 AML(Arc Macro Language)를 이용하여 강우-유출 모형을 구성하였다. 지표류에 대한 운동파의 해석은 특성곡선법을 이용하였으며, 본 모형의 적용성 검토를 위해 실측 유출곡선과 비교하였다. 그 결과 유출수문곡선의 형태는 실측치와 유사하였고, 첨두도달시간은 거의 일치하였으나 첨두유량은 재현성이 비교적 떨어지는 것으로 나타났다. 그리고 추적기간의 크기에 기인한 유출량의 변동성을 파악하기 위하여 추적기간을 600 (sec) 와 300 (sec)로 선정하여 관측된 두 호우사상에 대해 각각 적용한 결과 첨두도달시간은 거의 변화가 없었으며, 첨두유량은 각각 0.27%, 9.60%의 변화가 나타났다. This study is on the application and the verification of the rainfall-runoff model with distributed parameters of catchment. This model was constructed of cell-based and analyzed the surface flow by kinematic wave. The catchment for applying selected SAYUN DAM that was area of 125.4㎢ and main stream length of 23.4㎞. To construct the model, this study was using the digital elevation map(1:5,000) and landuse map(1:5,000) and a tool of GIS(Geographic Information System),Arc/Info and its interior language(AML), was used for the analysis of physiographic characteristics. This model was used method of characteristics for analysis of kinematic wave analysis. To verify the simulation, this study made a comparison between observed hydrograph and simulated one. As the simulated results showed that the shape of hydrograph was similar to the observed one, ut the peak flow relatively increased. And it verified the effects when the routing period changes as long period or short period. Routing period was selected mean equivalent time(600sec) and its half (300sec). The results that applied to two events was 0.27% and 9.60% in the peak flow and there was no changing the time of peak.

凍結深度 算定에 대한 硏究

민홍기,류제천,김송만,박춘수 忠南大學校 産業技術硏究所 1997 산업기술연구논문집 Vol.12 No.2

Korea has the ground which freezes in winter and melts in warmer seasons by turns. Therefore, in designing civil-structures or buildings on such ground, the depth of seasonal frost penetration must be considered. In this paper, approximate contours of the maximum depth of frost penetration in Korea is presented. The National Construction Research Institute of Korea has measured the depth of the frozen ground covering all the area of South Korea during the ten years ranging through 1980. The measurement were made for the frozen ground at random but intended for the most frost-susceptible soils. The contour of the maximum depth of the frost penetration is drawn on a map with data collected during the ten years. It is known that the maximum depth of the frost penetration is related to freeze index values. An empirical formula expressing the relation is suggested, in which the depth is proportional to the one-fifth power of the air freezing index values.

고등학교 과학(Ⅱ) 교과서 내용의 비교·분석 연구

오제직,홍춘표,김화영 공주대학교 사범대학 과학교육연구소 1994 과학교육연구 Vol.25 No.1

The purpose of this research is to compare and to analyze eight different science textbooks Ⅱ (the last volume) that are presently in use at the high school. The items that were compared and analrzed are as follows: The construction of each textbook in quantity. The construction of experimentation contents. The construction of contents in textbooks. This study will provide the basic data that is needed to effectively accomplish aims of science education and to enable a guidance teacher to reconstruct the textbook properly to the real condition exiting in each school. The findings of the research are as follows: 1. There is little difference in quantity of materials. But there is difference in quantity of each unit. 2. The number of Gothic-type terms used in each textbook is not unified. The sort of Gothic-type terms used in each textbook is also varied. 3. Photographs and pictures are presented in black and white. They are used for only explaining. 4. Material and method used in experimentation are showed in many ways. But some units are given too much importance. 5. Contents are consisted variously according to authors under the basic frame of education curriculum.

서해산 돌가자미 Kareius bicoloratus의 초기발생시 수온과 염분의 영향

전제천,김치홍,정의영,이창훈,김병균 한국어류학회 2002 韓國魚類學會誌 Vol.14 No.3

본 연구는 돌 가자미(Kareius bicoloratus)의 난발생에 미치는 수온과 염분의 영향을 알아보지 위하여 수행되었다. 5단계의 수온 조건 (7, 10, 13, 16 및 19℃) 및 5단계의 염분 조건(25, 30, 35, 40psu 및 현장해수 염분 : 33.6psu)에서 수정란을 발생시켜 발생 속도와 부화율 측정하였다. 수정란의 발생속도는 수온이 높을수록 빨랐으며, 수온(T: ℃)과 각 발생 단계별 소요시간(h:hour) 사이의 관계를 직선 함수에 회귀시켰을 때 각 발생단계별 관계식은 다음과 같다. 8세포기 : 1/h = 0.01441T - 0.02728(r^(2) = 0.998) 낭배기 : 1/h = 0.00269T - 0.00319(r^(2) = 0.997) 안포형성기 : 1/h = 0.00171T - 0.00053(r^(2) = 0.998) 심장형성기 : 1/h = 0.00121T - 0.00018(r^(2) = 0.995) 부화기 : 1/h = 0.00101T - 0.00266)(r^(2) = 0.998) 이상의 관계식으로부터 추정된 돌 가자미의 난 발생이 개시되는 생물학적 영도는 1.3℃이었다. 8세포기, 낭배기, 안포형성기. 심장형성기 및 부화기까지의 적산수온은 각각 72.9, 356.7, 525.8, 735.2 및 1156.7℃로 계산되었다. 수온은 부화율에 큰 영향을 미치는 것으로 나타났다(p<0.001). 부화율이 수온이 증가할수록 감소하였으며, 7℃일 때 부화율이 62.0%로 가장 높았다. 수온이 16℃ 이상일 때 기형어의 출현율이 증가하였다(p<0.05). 염분 또는 부화율에 큰 영향을 미치고 있었다(p<0.001). 염분에 따른 부화율은 자연해수의 염분인 33.6psu에서 54.1%로 가장 높았고, 이보다 낮거나 높은 경우에는 부화율이 감소하였다. 특히, 염분이 30psu 미만으로 감소할 경우 기형어의 출현율 증가하였다(p<0.04). 돌 가자미의 난 발생 및 정상적인 부화를 위한 조건은 산란시기의 수온과 염분에 가까울수로고 좋은 것으로 판단된다. This study was conducted to determine the influences of water temperature and salinity on the embryonic development of the stone flounder, Kareius bicoloratus as a part of research on the artificial seedling production of the fish. Embryos were incubated under five different temperatures (7, 10, 13, 16 and 19℃) and five different salinities (25, 30, 35, 40 psu and the ambient salinity: 33.6 psu) until they hatched. The required times for embryonic development decreased with increase of water temperature. The relationships between the water temperature (T: ℃) and required times (h: hour) for the embryo to attain each develop-mental stage were obtained by linear regressions as follows; 8-cell stage : l/h = 0.01441T-0.02728 (r² = 0.998) 50%-epiboly stage : Uh = 0.00269T-0.00319 (r² = 0.997) Optic vesicle formation stage : l/h = 0.00171T-0.00053 (r² = 0.998) Heart formation stage : l/h = 0.00121T-0.00018 (r² = 0.995) Hatching stage : l/h = 0.00101T-0.00266 (r²= 0.998) From these equations, the biological minimum temperature for embryonic development of K. bicoloratus was estimated to be 1.3℃. Cumulative water temperatures to reach 8-cell stage, 50%-epiboly stage, optic vesicle formation stage, hearth formation stage, and hatching stage were 72.9, 356.7, 525.8, 735.2, and 1,156.7℃, respectively. Water temperature affected significantly the hatching rate (p< 0.001). The hatching rate decreased with increase of water temperature. The highest hatching rate was 62.0% at 7℃. When the water temperature was higher than 16℃, the proportion of abnormal larvae increased (p < 0.05). Salinity also affected significantly the hatching rate (p< 0.001). The highest hatching rate was 54.1% at the salinity (33.6 psu) of ambient seawater. When the salinity was lower than 30 psu, the proportion of abnormal larvae increased ip < 0.05).