탄화물 입자 강화 7075 Al 합금 기지 복합재료의 미끄럼마멸 특성 연구

강석하,박형철,강신철,김용석 국민대학교 생산기술연구소 2002 공학기술논문집 Vol.25 No.-

Effects of the type and volume fraction of carbide-particle-reinforcements on dry sliding wear behavior of 7075 Al alloy matrix composites were investigated. SiC, TiC and B₄C reinforced 7075 Al alloy matrix composites were manufactured by a pressureless infiltration technique and wear tested. Wear tests were carried out using a pin-on-disk wear tester with varying loads of 3N-160N at a constant sliding velocity of 0.2m/s. AISI 52100 bearing steel ball was a counterpart of the composites. Wear resistance of the composites was always higher than that of the monolithic alloy except the TiC reinforced 7075 Al matrix composite. The resistance increased with the increase of volume fraction of the reinforcing particles. Among the composites, the TiC reinforced composite had the lowest wear resistance and the B4C reinforced composite showed the highest wear resistance.

Dock Wall에서 Pre-splitting 발파의 적용성에 관한 연구

강추원,고진석,강석곤 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

The contour blasting minimize the strain and the rocks are destroyed to the theoretical projected line by adding or substracting the explosive compound amounts. On pre-splitting blasting, the most important factors are the base rock conditions, accuracy of drilling, kind of explosive compound used, and charge. The first test blast is classified in eight groups, which is done to find more accurate blasting conditions after a variety of blasting methods are used. Through the conditions of charge of the first test blast, after the best blast method is selected the second test blast is performed. The number of holes and hole spacing are corrected on the second test blast, which takes change to reduce construction days and working conditions. In the second test blast charge conditions. Pattern Y is the method for see a cutting plane of 90˚ for the reducing of dock-wall parts.

탄화물 입자 강화 7075 Al 합금 기지 복합재료의 미끄럼마멸 특성에 미치는 기지 합금 변형의 영향

강석하,강신철,김용석 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4

Sliding wear behavior of 7075 Al alloy matrix composites was investigated. Reinforcements of the composite were SiC, TiC, and B_(4)C particles with various size and volume fractions. Sliding wear tests were carried out in an ambient atmosphere using a pin-on-disk wear tester with various loads of 5N-150N against a bearing steel ball counterpart. The composites showed higher wear resistance than the monolithic matrix alloy. Sliding wear of the composites proceeded by a grinding mechanism at low loads and by a delamination of a deformed layer at high loads. Wear resistance of the composites increased with the size and volume fraction of the reinforcements, and the increase was more significant at high applied loads. Deformation of the matrix was found to control the wear at high loads. The effect of heat treatment and reinforcement variation including size, volume fraction and species on the wear was discussed in connectin with the deformation of the matrix. (Received September 19, 2003)

Investigation of the April 2000 forest fire damage in Kang-won Province, Korea, using RADARSAT data

Kang, Sung Chul,Seo, Jin Won,Lee, Tae Hee,Park, Sang Eun,Hong, Suk Young,Moon, Wooil M. 대한원격탐사학회 2000 International Symposium on Remote Sensing Vol.16 No.1

The series of forest Fires in Kangwon Province in April, 2000, were one of the mast serious ones in the Kang-won Province in recent years. The fire damaged areas are extensive and this paper investigates the utility of the satellite image data, particularly the RADARSAT SAR data. One of the main objectives of this study included evaluation of potential usefulness of the C-band RADARSAT data in the detection of forest fires in mountainous areas. Among several fire damaged sites, the area near Samchuk (city) was selected as the main study area and mufti-temporal RADARSAT(raw) data were acquired and the processed results were comparatively investigated with the IRS-1c data acquired shortly after the fire. To identify the burnt area from the undamaged background in the optical imagery, supervised classification and NDVI processing were carried out and tested with the IRS-1C data. For this experiment, several sets of raw RADARSAT standard and Fine mode (S4, F3, ascending orbit) data were processed and the final image was formed. In addition to the final image, sigma nought (σ°) was catnputed and compared for the burnt area against the undamaged areas. Because of the steep slopes in the study area and subsequent deviation from the flat surface scattering models, the fire scars in the sigma nought (σ°) image were not apparent. However, fire scars are slightly detected in the difference and ratio images obtained from the signal intensity data acquired at different dates (bath before and after fire). Texture analysis of the image data including the burnt areas were carried out using the Multiplicative Markov Random-Field (MMRF) algorithm. The detection of the fire damaged area from both standard mode and fine mode RADARSAT was not as straightforward as in optical data. However, Previous studies with ERS-1 S_AR and RADARSAT data in Indonesia and in the North American Plains indicate that C-band SAR data provide us with an effective tool for studying the forest fire damages. However, the application of C-band SAR data to the analysis of the forest fire areas requires careful processing of the data with realistic scattering models.

A New Sesame Variety, “Kangbaek” with Disease Resistance, Lodging Tolerence and High Yield

Kang-Bo Shim,Churl-Whan Kang,Suk-Bok Pae,Si-Kyu Lim,Yu-Young Lee,Duck-Yong Suh,Jae-Whan Rho,Jin Song,Dong-Whi Kim,Ho-Young Kim 한국육종학회 2005 한국육종학회지 Vol.37 No.5

A new sesame variety Kangbaek was developed from Yeongnam Agricultural Research Institute in 2004. Cros wasmade by lodging resistant SP9003-3 line to the F1with high yielding capacity, folowed by pedigree selection, yield test and RYT by the sesame breeding team at the National Insti-tute of Crop Science up to 2003. The variety showed higher disease resistance, especially phytophothra disease, and lodging resis-respectively. It's 1000 grains weight was about 2.54 g indicating 0.03 g heavier than that of Yangbaekkae, and it's oil content wasabout 52%. Kangbaek also contained total 7.65mg/g of such lignans as sesamin and sesamolin. The average yield of Kang-baek was 82 kg per 10a at the national-wide regional performance.

현대 한국인의 호(號) 사용 양상 연구

강희숙(Kang Hui?suk) 한국사전학회 2016 한국사전학 Vol.- No.28

Our ancestors used diverse, different names through their life time as rite of passage. Unlike them, most of modern Koreans use only one name through their whole life. This research focuses on analysing use aspect of pseudonym of modern Koreans based on the fact that nowadays there is a increasing number of people using pseudonym. Findings show that not only cultural artists like Confusian scholars of Hyanggyo, calligrapher, traditional painters or poets, and tea ceremony artists, but also professions like professors, doctors, lawyers and public officers on the research area are using pseudonyms. Most of the pseudonyms in traditional society were given by user him or herself, but now only 8.3% of pseudonyms were selfᐨnamed. More than half of the psedonyms are named by their teachers(53.6%). And characteristics of name authors became so diverse that 14.3% of people were given pseudonyms by their acquaintances, 7.2% by their friends, 4.5% by Buddhists monks, 4.2% by scholars of Chinese classics, and 3% by professional names. These pseudonyms are used as symbol of right or status, but is also confirmed that they also functioned as a sign that the person has such a high dignity that his or her real name should not be used freely. Also not like traditional pseudonyms were generally came from the name of the specific area the person dwelled or he or she consider it special, 44.2% of pseudonyms on this research derived from the person"s life lesson or life motto and they took the highest percentage of research. And there were not a few pseudonyms derived from native words such as "Yeoul, Jinsaem, Dolsaem, Danbi, Haemil, Butsame, Aran". Pseudonyms are symbols of social self identity that represent one"s will and mind, It is significant that it became possible to have an insight into the life motto of people use pseudonyms through this research

추적조사를 중심으로 한 腰椎間板脫出症에 대한 蜈蚣藥鍼의 臨床的 硏究

최회강,소기숙,고강훈,박소영,김성남,이종덕,원경숙,문형철,김성철 大韓鍼灸學會 2003 대한침구의학회지 Vol.20 No.3

Objective : This study is performed for the purpose of examining the efficacy of the scolopendrid(Scolopendra morsitans L) which has been to low back pain as a folk remedy. Methods & Results : Seventy patints with H.I.V.D. treated with the scolopendrid aquacupuncture and examined 4 tests; D.I.T.I., physical test, Oswestry disability index, and self-conscious pain rate were studied. And we follow up after discharge, we evaluated the present state and recovery period. Or we evaluated by herniated type and duration of onset. There was 58~97% of efficacy rate in each tests. Moreover, statistically valuable change in all 7D.I.T.I. points and in disability index and in self-conscious pain rate was showed. Conclusion : The scolopendrid aquacupuncture is possible to be effective terating the H.I.V.D patients. so we suggest the possibility using this new remedy to the H.I.V.D. patients.

알카리성 부여제 도포에 의한 중성화된 콘크리트의 알카리성 회복성능에 관한 실험적 연구

김무한,권영진,강석표,유재강,이강우 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

Concrete is the most commonly used material in construction field and it is the permanent construction material with respect to civil property. But, if concrete loses its alkalinity by CO2 gas, it loses its structural characteristics and results in total collapse in construction field. Therefore. it is needed to be studied the alkali-recovery performance by alkalization agent on carbonated concrete by accelerated carbonation test. In this paper, we investigate recovery performance by impregnating alkalization agent in carbonated concrete, then we evaluate alkali maintenance performance by pH survey in each kinds of finishing materials. The results of this paper can be summarized as follows. 1)Carbonated concrete under pH 10 was recovered its alkalinity to pH 11 at first stage by spreading alkalization agent on its outer surface. 2)After spreading alkalization agent, there is a difference due to types of moreover effect of anti-rust paint and ordinary cement paste were excellent.

우라늄 투여후 간조직에서의 효소활성도의 변화

김국찬,이강석,김진규,김인규,박효국,천기정,김상복 대한방사선 방어학회 1993 방사선방어학회지 Vol.18 No.2

우라늄 피폭후 효소활성도가 내부피폭의 biomarker로서의 가능성을 연구하기 위하여 수서생물인 잉어9Caprinus carpio)의 복강내 우라늄 투여시 간조직에서 일어나는 여러가지 효소계의 변화를 조사하였다. 이러한 효소활성도의 변화는 우라늄 내부피폭의 biomarker로서 가능성을 가지고 있으며 연구결과는 다음과 같다. 1) 6일째까지 우라늄을 주사하여 적출한 간에서의 전체단백질량은 계속 감소하고 있다. 2) 세포내의 lysosome내에 함유하고 있는 acid protease와 β-glucuronidase의 활성도는 6일째 투여후까지 활성도가 감소하고 있다. 3) Alkaline phosphatase의 경우 6일째 우라늄 투여후까지 증가하고 있으며 반대로 acid phosphatase의 경우 6일째 우라늄 투여후까지 활성도가 급격히 증가하였고 glutamate oxaloacetate transaminase의 활성도는 완만하게 증가하고 있다. 4) Creatine kinase의 활성도는 완만한 감소를 보이고 있으며 malate dehydrogenase는 첫번 우라늄 투여후에 활성도가 급격히 감소하였고 3일째 우라늄 투여후에는 활성도가 거의 나타나지 않았다. We examined various enzyme activity changes by intraperitioneal injection uranium in the carp liver. These enzyme activity changes can be used as biochemical indicators of internal exposure to uranium. The results were followings ; 1) Total protein concentration decreased by intraperitoneal injection in the carp liver. 2) Lysosomal acid protease and β-glucronidase activities increased in the liver until sixth intraperitoneal injection of uranium, but lysosomal acid phosphatase activities decreased in the liver until the sixth injection of uranium. 3) Alkaline phosphatase activities sharply increased and Glutamate oxaloacetate Transaminase activities steadily decreased in the liver until the sixth injection of uranium. 4) Creatine %kinase activities steadily decreased and malate dehydrogenase activities sharply decreased in the liver after the primary injection of uranium. Any malate dehydrogenase activities was not detected after sixth injection of uranium.

冪函數 分布의 로렌쯔 曲線과 지니 指數의 推定

姜錫福,趙瑛錫 嶺南大學校 基礎科學硏究所 1991 基礎科學硏究 Vol.11 No.-

In this paper, we obtain the maximum likelihood estimator, the uniformly minimum variance unbiased estimator and a strongly consistent asymptotically normal unbiased estimator for each of Lorenz curve and Gini index of a power function distribution. The mean square error of each estimator is derived in terms of several special functions. The unmerical values of the mean square errors are also obtained.