• 한국산학기술학회논문지
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• 제1권1호
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• pp.43-48
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• 2000

화학적 활성법과 수증기 활성법을 이용하여 활성탄소섬유를 제조한 결과 수증기 활성법 보다 우수한 표면 특성을 얻을 수 있었으며, 이 결과를 이용하여 탄소재료의 새로운 응용분야 개척 차원에서 항균성 활성 탄소섬유를 제조하였다. 기능성이 부가된 활성 탄소섬유의 비표면적이 544.27-1575.6 ㎠/g. 평균동공 반경이 10.6-12.9 (equation omitted)의 범위에 존재하였다. 항균성 활성 탄소섬유의 흡착등 온곡선의 유형이 전형적인 Tyre I을 나타냄을 알 수 있었으며 SEM을 이용하여 관찰한 모폴로지를 통하여 이들의 표면에 항균물질이 덮혀있는 상태를 관찰하였다. 마지막으로 항균 활성 탄소섬유에 대장균의 일종인 E. Coli를 처리하여 얻은 항균 활성의 결과를 보였다. 결론적으로, 활성 탄소섬유의 응용 분야 확대를 위하여 살균·탈취·방충 등의 기능성 부여가 가능함을 보여주었다.

• 대한원격탐사학회지
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• 제25권2호
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• pp.113-126
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• 2009

Terra와 Aqua 위성에서 촬영되는 MODIS 영상은 매일 수신되는 중해상도 영상으로써 광범위한 지역에 대한 모니터링을 하는데 여러가지 장점을 제공한다. 특히, MODIS 영상은 신뢰성 있는 알고리즘을 적용하여 만들어진 대기/해양/육상 관련한 여러 가지 영상(products)들을 함께 제공함으로써 사용자가 데이터를 확보하여 바로 사용할 수 있는 장점을 가지고 있다. 또한 북한이라는 제도적으로 제약이 따르는 지역을 포함하는 한반도의 경우, 활용상의 제약이 따르지 않는 점이 중해상도급 MODIS 영상의 큰 장점이라고 할 수 있다. 본 연구는 기존의 시계열 모니터링에서 주로 식생지수를 모니터링하는 방법과는 달리, 대기 보정을 거쳐 대기의 효과를 제거한 250m급 MODIS 반사율 영상을 이용하여 시계열로 변화되는 반사율을 대상으로 하였다. 2004년에서 2008년까지 5년 동안의 각 토지 피복이 보이는 반사율 패턴과 함께, 토지 피복이 변화된 지역에서 관찰되는 반사율의 변화를 살펴보았다. 7개의 토지 피복별 근적외선, 적색광 반사율과 NDVI의 시계열 자료에서 토지 피복과 계절적 영향이 근적외선 반사율에서 가장 민감하게 반영되고 있는 것을 알 수 있다. 토지 피복에 따른 반사율 패턴은 토지 피복 분류 및 변화된 지역을 탐지하는데 기본적으로 이용될 가능성을 제시한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.51.2-51.2
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• 2015

Understanding interfacial phenomena has been one of the main research issues not only in semiconductors but only in life sciences. I have been trying to meet the atomic scale surface and interface analysis challenges from semiconductor industries and furthermore to extend the application scope to biomedical areas. Optical imaing has been most widely and successfully used for biomedical imaging but complementary ion beam imaging techniques based on mass spectrometry and ion scattering can provide more detailed molecular specific and nanoscale information In this presentation, I will review the 27 years history of medium energy ion scattering (MEIS) development at KRISS and DGIST for nanoanalysis. A electrostatic MEIS system constructed at KRISS after the FOM, Netherland design had been successfully applied for the gate oxide analysis and quantitative surface analysis. Recenlty, we developed time-of-flight (TOF) MEIS system, for the first time in the world. With TOF-MEIS, we reported quantitative compositional profiling with single atomic layer resolution for 0.5~3 nm CdSe/ZnS conjugated QDs and ultra shallow junctions and FINFET's of As implanted Si. With this new TOF-MEIS nano analysis technique, details of nano-structured materials could be measured quantitatively. Progresses in TOF-MEIS analysis in various nano & bio technology will be discussed. For last 10 years, I have been trying to develop multimodal nanobio imaging techniques for cardiovascular and brain tissues. Firstly, in atherosclerotic plaque imaging, using, coherent anti-stokes raman scattering (CARS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) multimodal analysis showed that increased cholesterol palmitate may contribute to the formation of a necrotic core by increasing cell death. Secondly, surface plasmon resonance imaging ellipsometry (SPRIE) was developed for cell biointerface imaging of cell adhesion, migration, and infiltration dynamics for HUVEC, CASMC, and T cells. Thirdly, we developed an ambient mass spectrometric imaging system for live cells and tissues. Preliminary results on mouse brain hippocampus and hypotahlamus will be presented. In conclusions, multimodal optical and mass spectrometric imaging privides overall structural and morphological information with complementary molecular specific information, which can be a useful methodology for biomedical studies. Future challenges in optical and mass spectrometric imaging for new biomedical applications will be discussed.

• 한국환경과학회지
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• 제19권5호
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• pp.577-584
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• 2010

The generation of $TiO_2$ nanoparticles by a thermal decomposition of titanium tetraisopropoxide (TTIP) was carried out experimentally using a tubular electric furnace at various synthesis temperatures (700, 900, 1100 and $1300^{\circ}C$) and precursor heating temperatures (80, 95 and $110^{\circ}C$). Effects of degree of crystallinity, surface area and anatase mass fraction of those $TiO_2$ nanoparticles on photocatalytic properties such as decomposition of methylene blue was investigated. Results show that the primary particle diameter obtained from thermal decomposition of TTIP was considerably smaller than the commercial photocatalyst (Degussa, P25). Also, those specific surface areas were more than 134.4 $m^2$/g. Resultant $TiO_2$ nanoparticles showed improved photocatalytic activity compared with Deggusa P25. This is contributed to the higher degree of crystallinity, surface area and anatase mass fraction of $TiO_2$ nanoparticles compared with P25.

• 한국의류학회지
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• 제48권3호
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• pp.501-510
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• 2024

This study aimed to compare the cooling effect of specific body parts to increase workers' thermal comfort. The parts to be cooled comprised the head and neck; the coolant was a phase change material. The participants were ten men in their 20s of average size according to the 8th Size Korea. The experiment was conducted under the following conditions: 28.0 ± 0.5℃, 60.0 ± 5.0% RH, and 0.2 ± 0.1m/s. The exercise consisted of participants moving for 15 min at a constant speed of 80 BPM; later, a subjective sensation was performed, and the clothing surface temperature was measured. In doing so, heat, wetness, and discomfort after exercise were confirmed to have increased without a coolant. Significant differences over time appeared only when no coolant was used, showing that thermal comfort decreased. Despite the addition of coolant, the clothing surface temperature gradually increased over time, but it decreased with coolant rather than without it. Therefore, additional coolant areas, a lower temperature, and simultaneous cooling convection were required to improve thermal comfort.

• 한국염색가공학회지
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• 제1권1호
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• pp.19-25
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• 1989

In past, dye diffusion and dyeing rate in fibers have been emphasized in dyeing phenomena. However, in the light of the properties of colloids in the surface of disperse phase and dispersion, there exist specific characters such as adsorption or electric double layer, which seems to play important roles in determining the physiochemical properties in the dyeing system. Electrostatic bonding, hydrogen bonding and Van der Waals adsorption are common in dyeing as well as covalent bonding. Particularly, electrostatic bonding is premised on the existance of ionic radicals in fibers. The present study was aimed to clarify the electrokinetic phenomena of dyeing through the role of electric double layer by ion in amphoteric fibers with different ionic effects under different pH. Spectrophotometric analysis method was used to compare dyeing condition of surface, which can be detected by electrokinetic phenomena and the inner of fibers after deceleration of dyed fibers. Nylon and wool, the typical amphoteric fibers were dyed with monoazo acid dyes such as C.I. Acid Orange 20, and C.I. Acid Orange 10. Various combinations were prepared by combining pH, temperature and dye concentration, in order to generate streaming electric potential which were measured by microvolt meter and specific conductivity meter. The results were transformed to zeta potential by Helmholtz-Smoluchowski formular and to surface electric charge density by Suzawa formular, surface dye amount, and effective surface area of fibers. The amount of dyes of inner fibers were also measured by the Lambert-Beer’s law. The main results obtained are as follows. 1. By measuring zeta pontential, it was possible to detect the dyeing mechanism, surface charge density, surface dye amount and effective surface area concerning dye adsorption of the amphoteric fibers. 2. Zeta pontential increases in negative at low pH and high dye concentration in the process of dyeing. This implied that there existed ionic bond formation in the dyeing mechanism between acid dyes and amphoteric fibers. 3. Dibasic acid dye had little changing rate in zeta potential due to the difference in solubility of dye and in number of dissociated ions per dye molecule to bond with amino radicals of amphoteric fibers. The dye adsorption of mono basic acid dye was higher than that of dibasic acid dye. 4. The effective surface areas concerning dyeing were $6.3E+05\;cm^2/g$ in nylon, $1.6E+07\;cm^2/g$ in wool fiber being higher order of wool then nylon.

• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.150-158
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• 2007

Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.

• Asian Pacific Journal of Cancer Prevention
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• 제16권5호
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• pp.1959-1964
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• 2015

Purpose: To investigate the distribution of liver cancer mortality as well as its developing trend from 1991 to 2012, forecast the future five-year trend, and provide a basis for the comprehensive prevention and management. Materials and Methods: Mortality data for liver cancer in China from 1991 to 2012 were used to describe characteristics and distribution of liver cancer mortality. Trend surface analysis was used to study the geographical distribution of liver cancer mortality. Curve estimation, time series modeling, gray modeling (GM) and joinpoint regression were used to predict and forecast future trends. Results: The mortality rate of liver cancer has constantly increased in China since 1991. Rates in rural areas are higher than in urban areas, and in males are higher than in females. In addition, our data predicted that the trend will continue to increase in the next 5 years. The age-specific mortality of liver cancer increases with age and peaks in the group of 80-84 years old. Geographical analysis showed the liver mortality rate was higher in the southeast provinces, such as Jiangsu, Zhejiang and Guangdong, and southwest regions like Guangxi Province. Conclusions: The standardized mortality rate of liver cancer in China has consistently increased from 1991 to 2012, and the upward trend is predicted to continue in the future. Much better prevention and management of liver cancer is needed in high mortality areas (the southwestern and southeastern parts of China) and high mortality age groups (80- to 84-year-olds), especially in rural areas.

• Journal of Welding and Joining
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• 제16권4호
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• pp.55-62
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• 1998

While excellent joint quality has been obtained using dry chamber underwater welding methods, the size limitations imposed by this process restrict its use for underwater construction work. The wet underwater shielded metal-arc welding eliminates this restriction but suffers from poor weld properties by the 1-pass bead-on-plate welding due to the excessive diffusible hydrogen. On the other hand, in the wet underwater welding, it is well known that the quantity of diffusible hydrogen in multi-pass welded parts reduce to less than that in 1-pass welded parts. Therefore, in this paper, welding experiments are made the 3-pass bead-on-plate welds by using TMCP and normalized steel plates and E4301 and cellulose coated electrode. After that, The amounts of the hydrogen absorbed into the 3-pass welded area were measured according to the JIS Z 3118 specification. The microstructural changes as well as the microhardness distribution after the underwater 3-pass welding were also investigated using Vickers microhardness tester and S.E.M and O.M. The results indicated that the quantity of diffusible hydrogen in 3-pass welded areas was reduced little less than a half of one of that in 1-pass welded areas at the specific welding condition. As a result, the cold cracking of 3-pass welded areas decreased by reduced effect of diffusible hydrogen. In the underwater 3-pass welding, the micrography of cold cracking fracture surface showed mainly the cleavage of hydrogen embrittlement.

• 응용통계연구
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• 제18권2호
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• pp.281-296
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• 2005

본 연구에서는 2004년 기상청 집중관측기간(KEOP)에 수집된 지상관측자료를 사용하여 한반도 남서지방의 지역별(해남 외 7개 지역) 기상인자들의 주기성과 이들이 강수현상에 미치는 영향을 분석하였다. 이를 위하여 기술통계와 스펙트럴분석을 사용하여 주기성을 분석하고, 관측기간 및 지역별 랜덤효과를 반영할 수 있는 일반화 선형모형을 제시하여 강수현상에 미치는 기상인자들의 영향을 분석했다. 분석결과에 의하면 기상인자들과 강수현상은 연관성을 가지며 특정주기에 따라 변동하는 것으로 나타났으며, 기상인자들은 지역에 따라 상이한 패턴으로 강수현상에 영향을 미치는 것으로 나타났다.