• Elastomers and Composites
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• 제34권5호
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• pp.383-390
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• 1999

Functionally graded polyurethane elastomers PUEs/grad. Poly(dimethylammoninum ethylacrylate bromide)(PDMAEA) were prepared by the method of electrophoresis. Results of elemental analysis showed that concentration of PDMAEA had gradient across the thickness(2mm) of the base PUEs. The modified PUEs(PUEs/grad. PDMAEA) containing high concentration of PDMAEA displayed low degree of swelling in benzene which was poor solvent for PDMAEA, and high degree of swelling in water which was good solvent. For the each layer of modified PUEs, glass transition temperature, dynamic storage modulus were stooled by DSC, Rheovibron DDV-IIC dynamic viscoelastomer. The chemomechanical properties of modified PUEs was explored by the electric-stimulus.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.58-59
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• 2012

Surface hardening mechanism of H13 steel was investigated when ion niriding after shot peening process was applied. Severe plastic deformation induced nanocrystallized grains at surface region. Higher nitrogen concentration was achieved in ion nitrided specimen with shot peening treatment than in single nitrided specimen. The elemental mapping on chromium and nitrogen by TEM-EELs showed chromium dissolved in matrix enhanced bulk nitrogen diffusion at surface region. Higher nitrogen diffusion also caused lattice distortion. Nano-sized grains, higher nitrogen concentration, and lattice diffustion contributed to the surface hardening.

• Macromolecular Research
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• 제16권8호
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• pp.670-675
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• 2008

A series of pH and temperature-responsive (N,N-diethylacrylamide-co-methylacrylic acid) copolymers were synthesized by radical copolymerization and characterized by elemental analysis, Fourier-transform infrared (FT-IR), nuclear magnetic resonance (NMR) $^1H$, $^{13}C$ and LLS. The effects of salt and pH on the phase transition behaviors of the copolymers were investigated by uv. With increasing NaCl concentration, significant salt effects on their phase transition behaviors were observed. UV spectroscopic studies showed that the phase transition became faster with increasing NaCl concentration. In addition, the phase transition behaviors of copolymers were sensitive to pH. The pH and temperature sensitivity of these copolymers would make an interesting drug delivery system.

• 한국지구과학회지
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• 제24권5호
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• pp.477-490
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• 2003

한국 동해안 영일만 해역에서 퇴적물의 금속 함량과 공간 변화 특성을 연구하기 위해 총 27개의 표층 퇴적물을 채취하여, 입자조직, 유기탄소, 금속 원소들의 함량을 분석하였다. 연구해역애서 표층 퇴적물의 입도는 전반적으로 해안선 부근에서 조립하고 만의 중앙부에서 세립하며, 이러한 공간 변화는 해저지형과 반시계방향의 해류 패턴에 의한 것으로 해석된다. 유기탄소와 금속 원소들의 함량은 대부분 퇴적물의 입도 변화에 수반되어 니질 함량이 높은 만의 중앙부에서 높고 사질 함량이 높은 해안선 쪽으로 갈수록 낮아진다. 그러나 칼슘, 스트론튬, 칼륨의 함량은 조립한 퇴적물이 우세한 해안선 부근 퇴적물에서 높고, 몇몇 중금속(구리, 아연, 카드뮴) 함량 또한 유기물 함량이 매우 높은 구항과 형산강 입구의 퇴적물에서 높은 특징을 보인다. 상관관계 및 요인분석 결과에 의하면, 대부분의 금속 원소들의 함량과 공간 변화는 퇴적물의 입도에 의해 조절되는 것으로 보이나, 카드뮴, 구리 아연, 주석 등은 퇴적층의 무산소 환경에서 일어나는 지화학적 메카니즘이 이들의 함량과 공간 변화를 조절하는 일차적인 요인으로 제시된다. 약산추출 부분(labile fraction)의 함량과 농축비(concentration enrichment ratio) 연구결과에 의하면, 중금속 원소들의 존재 형태가 대부분 "sulfide minerals"와 관련된 것으로써, 이들의 형성과 축적이 일부 연구해역에서 중금속 오염의 주원인으로 제시된다. 한편, 칼슘과 스트론튬 경우에는 퇴적물에 함유된 패각 함량에 의해, 그리고 칼륨은 사질 퇴적물에 우세한 장석(feldspar) 광물에 의해 조절되는 것으로 해석된다.

• 대한수의학회지
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• 제43권3호
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• pp.423-428
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• 2003

진흙버섯 품종별 P. linteus, P. baumii 그리고 P. gilvus에 대한 형태학적 차이, 일반성분 및 무기성분을 조사하였다. 전자현미경 사진에서 P. gilvus와 P. linteus는 비슷한 형태를 보여주고 있다. 원소 함량의 구성비에서는 세 종류의 버섯이 모두 유사함을 보여주었다. 일반성분을 분석 비교시 수분의 함량은 P. baumii가 가장 높았으며 P. gilvus의 수분 함량은 10% 이내로 낮은 경향을 보여주었다. 식이섬유는 약 30% 이상을 함유하고 있으나 vitamin C 및 단백질의 함량은 높지 않았다. 원소분석에서 Ca의 경우 세 종류의 진흙버섯에서 P. baumi가 가장 높은 Ca 함량을 보여주었으나 통계적유의성은 없었다. 그러나 원소조성 및 일반성분 비교에서는 P. linteus, P. baumii 그리고 P. gilvus의 큰 차이점이 나타나지 않았다.

• 한국식품영양과학회지
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• 제46권10호
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• pp.1195-1204
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• 2017

본 연구는 애호박, 쥬키니, 단호박 및 늙은호박 조리방법에 따른 무기성분 변화를 확인하고자 하였다. 조리방법은 데치기, 전자레인지 및 찌기를 이용하였으며, 조리시간은 3분, 5분 및 10분으로 설정하였다. 설정된 시간에 따라 3가지 조리방법을 이용하여 조리한 후 건조하였다. 건조된 시료는 분쇄 후 microwave법을 이용하여 분해하였으며, 다량 무기성분은 ICP-OES로, 미량 무기성분은 ICP-MS를 이용하여 분석하였다. 4종의 호박에 함유된 다량 무기성분은 칼륨, 인, 칼슘, 마그네슘, 황, 철, 아연, 나트륨 순으로 확인되었으며, 미량 무기성분은 망간, 구리, 루비듐, 바륨, 니켈, 크롬, 갈륨, 코발트, 리튬, 바나듐, 셀레늄 순으로 검출되었다. 4종의 호박에 함유된 무기성분은 데치기, 전자레인지 조리 및 찌기에서 모두 감소하였으며, 데치는 조리에서 가장 많은 감소를 보였다. 조리시간에 따른 무기성분의 함량 변화는 조리시간이 증가할수록 낮은 함량을 보였으며, 5분과 10분에서 큰 차이를 확인하였다. 미량 무기성분의 함량은 조리방법과 조리시간에 따른 큰 변화를 확인할 수 없었다. 호박의 종류에 따른 무기성분의 조성은 비슷하였으며, 무기성분의 함량은 약간의 차이를 나타내었다. 애호박과 늙은호박의 무기성분은 찌는 조리법에서 높은 잔존율을 보였으며, 쥬키니와 단호박은 전자레인지 조리 시 가장 높은 잔존율을 나타내었다. 결과적으로 조리방법과 시간은 호박의 무기성분 잔존량에 영향을 주는 것으로 확인되었다.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E1호
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• pp.1-11
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• 2005

The concentration levels of gaseous elemental mercury (GEM) in ambient air have been investigated from a monitoring station located in Yang Jae district of Seoul, Korea for a long-term period covering 1997 through 2002. The mean concentration of Hg, if computed based on its hourly measurement data for this six-year period, was $5.32\pm3.53 ng m^{-3} (N = 27,170)$. The inspection of the diurnal distribution patterns indicated the presence of notably high concentration levels during nighttime relative to daytime (e.g., the mean hourly value as high as $9 ng m^{-3}$ in winter nighttime). When divided seasonally, the highest mean of $6.12 ng m^{-3}$ was also observed during winter followed by spring, fall, and summer. The results of our analysis confirmed the relative dominance of winter (seasonally) or nighttime (diurnally), while exhibiting a complicated trend on a long-term basis. Examination of our data over a different temporal scale consistently indicated that dynamic changes in Hg concentrations occurred through time in line with changes in the strength and diversity of the source processes. It is thus acknowledged that the presence of unusually high Hg levels is the consequence of intense man-made activities, while such signatures can vary in a competitive manner.

• Asian Journal of Atmospheric Environment
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• 제11권3호
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• pp.176-183
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• 2017

Although it is well known that rain plays an important role in capturing air pollutants, its quantitative evaluation has not been done enough. In this study, the effect of raindrop size on pollutant scavenging was investigated by clarifying the chemical nature of individual size-resolved raindrops and their residual particles. Raindrops as a function of their size were collected using the raindrop collector devised by our oneself in previous study (Ma et al., 2000) during high atmospheric loading for $PM_{2.5}$. Elemental analyses of solid residues and individual residual particles in raindrops were subsequently analyzed by Particle Induced X-ray Emission (PIXE) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX), respectively. The raindrop number concentration ($m^{-2}h^{-1}$) tended to drastically decrease as the drop size goes up. Particle scavenging rate, $R_{sca.}$ (%), based on the actual measurement values were 38.7, 69.5, and 80.8% for the particles with 0.3-0.5, 0.5-1.0, and $1.0-2.0{\mu}m$ diameter, respectively. S, Ca, Si, and Al ranked relatively high concentration in raindrops, especially small ones. Most of the element showed a continuous decrease in concentration with increasing raindrop diameter. The source profile by factor analysis for the components of residual particles indicated that the rainfall plays a valuable role in scavenging natural as well as artificial particles from the dirty atmosphere.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.449-454
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• 2006

Here we present a sensitive DNA detection protocol using quantum dots (QDs) and magnetic beads (MBs) for large volume samples. In this study, QDs, conjugated with streptavidin, were used to produce fluorescent signals while magnetic beads (MBs) were used to isolate and concentrate the signals. The presence of target DNAs leads to the sandwich hybridization between the functionalized QDs, the target DNAs and the MBs. In fact, the QDs-MBs complex, which is bound using the target DNA, can be isolated and then concentrated. The binding of the QDs to the surface of the MBs was confirmed by confocal microscopy and Cd elemental analysis. It was found that the fluorescent intensity was proportional to concentration of the target DNA, while the presence of non-complementary DNA produced no significant fluorescent signal. In addition, the presence of low copies of target DNAs such as 0.5 pM in large volume samples up to 40mL was successfully detected by using a magnet-assisted concentration protocol which consequently results in the enhancement of the sensitivity more than 100-fold.

• 세라미스트
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• 제22권4호
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• pp.357-367
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• 2019

Secondary Ion Mass Spectrometry(SIMS) is an analytical method that measures the distribution and concentration of elements or compounds by analyzing the mass of secondary ions released by irradiating ion beams with energy of hundreds eV to 20 keV on the sample surface. Unlike other similar analytical instruments, SIMS directly detect the elemental ions that constitute a sample, allowing you to accurately identify components and obtain concentration information in the depth direction. It is also a great feature for measuring isotopes and analyzing light elements, especially hydrogen. In particular, with the development of materials science, there is an increasing demand for trace concentration analysis and isotope measurements in the micro-regions of various materials. SIMS has a short history compared to other similar methods; nevertheless, SIMS is still advancing in hardware and is expected to contribute to the development of materials science through research and development of advanced analytical techniques.