• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2966-2970
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• 2012

Fullerene/polystyrene ($C_{60}$/PS) nano particle was prepared by using emulsion polymerization. Styrene and fullerene were emulsified in aqueous media in the presence of poly(N-vinyl pyridine) as an emulsion stabilizer, and polymerization was initiated by water soluble radical initiator, potassium persulfate. The obtained nano particles have an average diameter in the range of 400-500 nm. The fullerene contents in the nano particle can be controlled up to 15 wt % by varying the feed ratio, which was confirmed by themogravimetric analysis (TGA) and elemental analysis (EA). The structure and morphologies of the $C_{60}$/PS nano particles were examined by various analytical techniques such as dynamic light scattering (DLS), scanning electron microscope (SEM), transmission electron microscope (TEM), electron diffraction (ED) pattern, X-ray powder diffraction (XRD), and UV spectroscopy. Unlike conventional $C_{60}$/PS particles initiated by organic free radical initiators, in which the fullerene is copolymerized forming a covalent bond with styrene monomer, the prepared $C_{60}$/PS nano particles contain pristine fullerene as secondary particles homogeneously distributed in the polystyrene matrix.

• Applied Microscopy
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• v.42 no.2
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• pp.111-114
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• 2012

The scanning electron microscopy is an ideal technique for examining plant surface at high resolution. Most hydrate samples, however, must be fix and dehydrate for observation in the scanning electron microscope. Because the microscopes operate under high vacuum, most specimens, especially biological samples, cannot withstand water removal by the vacuum system without morphological distortion. Cryo-techniques can observe in their original morphology and structure without various artifacts from conventional sample preparation. Rapid cooling is the method of choice for preparing plant samples for scanning electron microscopy in a defined physiological state. As one of cryo-technique, high-pressure freezing allows for fixation of native non-pretreated samples up to $200{\mu}M$ thick and 2 mm wide with minimal or no ice crystal damage for the freezing procedure. In this study, we could design to optimize structural preservation and imaging by comparing cryo-SEM and convention SEM preparation, and observe a fine, well preserved Arabidopsis stem's inner ultrastructure using HPF and cryo-SEM. These results would suggest a useful method of cryo-preparation and cryo-SEM for plant tissues, especially intratubule and vacuole rich structure.

• Analytical Science and Technology
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• v.24 no.2
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• pp.61-68
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• 2011

Ni-coated alumina was prepared by sonochemical method. To increase an efficiency of Ni coating on alumina, amorphous alumina was prepared by sol-gel method and Ni was coated to fine particles of alumina. Ni-coated alumina was prepared from various calcination temperatures ($500^{\circ}C$, $1,000^{\circ}C$), concentrations of Ni solution (0.01 M~0.2 M) and sonochemical reaction times (30 min, 2h). The prepared fine particles were characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), and Particle Size Analyzer (PSA). The coating amount of Ni increased, as Ni concentration and ultrasonication time increased. The maximum amount of Ni was coated to fine particles of alumina, when Ni-coated alumina was prepared with 0.1 M concentration of Ni solution for 2 h of sonication time at $1000^{\circ}C$ of calcination temperature. The average particle size was in the range of 835.9 to 986.7 nm.

• Applied Microscopy
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• v.39 no.1
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• pp.73-77
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• 2009

Contaminative artifacts such as carbonaceous materials on carbon-coated microgrids are unavoidable, which is induced by electron beam exposure inside electron microscopes. This phenomenon raise a source to produce confusing information to the samples investigated by analytical TEM, which should be alleviated as much as possible. As experimental precautions for reducing this unwanted effect, the use of $LN_2$ cooled anti-contaminator and pre-illumination of electron beam at low magnification can be helpful. Nevertheless, we should be cautious to set an illumination condition for microanalysis because the contaminative effect is dependent with the types of irradiation situations, which is well known to be a decisive factor for causing the carbonaceous artifacts. Accordingly, it is necessary that optimal illumination to minimize the contaminative effect should be selected for improving the accuracy of microanalysis. In this paper, we introduce the practical method to determine the optimal illumination condition by evaluating the contaminative effect as a function of instrumental spot size, which is directly linked with electron current density.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.464-471
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• 1995

메그네트론 스퍼터링으로 제작한 고밀도 다층박막($Co_75{{Pt_12}{Cr_13}}$합금) 디스크를 투과전자현미경을 이용해 단면 및 평면의 미세조직의 조사 혹은 미소부위 성분분석을 할 경우, 선행되어야하는 시편준비 경로와 각 단계별 구체적방법 및 그 효과를 연구하였다. Ion밀링시간이 증가함에 따라 시료가 얇게 되는과정에서 스퍼터링된 물질이 관찰될 시편부위의 다른 표면에 증착되므로써 미세조직의 선명도를 해칠 수 있고, 이로인한 해석상의 오류가능성이 시사되었다. 또한, 자기박막 디스크와 같이 다층으로 구성된 단면분석용 시료에서는 서로 맞붙인 실리콘 단결정 접착면을 따라 밀링속도가 선택적으로 커서 우선축이 생김으로써 양질의 시편을 얻기 어려운 문제점이 제기되었다. 이같은 문제를 포함한 전자현미경 시료준비과정에서 생길 수 있는 문제를 해결할 수 있는 실마리와 이를 이용해 수행한 전자현미경 분석결과 및 효과적인 시편준비방법이 본 논문에서 언급되었다.

• Analytical Science and Technology
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• v.7 no.2
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• pp.155-164
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• 1994

A conventional Grimm-type glow discharge source was constructed and applied to radio-frequency(13.56MHz) discharge for metal and ceramic analysis. We investigated the emission spectrum for aluminium and aluminium oxide and the influence of discharge operating paramaters including argon pressure, rf-power and DC-bias voltages at the sample-side electrode. Scanning Electron Microscope(SEM) also was used to investigate the effect of rf-sputtering on the microstructure formation of the aluminium oxide. Linear analytical calibration curves were constructed for Manganese and zinc element in samples of low alloy steel(BAS 401-405) and brass(NIST 1108-1117).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.4
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• pp.333-340
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• 2013

Objectives: This study was designed to establish an accurate analytical method for asbestos in a biological sample for determining occupational asbestos-related diseases and relief of the health effects of environmental asbestos. Methods: Biological samples were obtained from lungs of rats following intratracheal instillation of asbestos(Chrysotile, anthophyllite) and were prepared according to digestion method(Wet digestion, high temperature ashing, low temperature ashing). The samples were then analyzed for asbestos fibers using a transmission electron microscope equipped with an energy dispersive X-ray spectrometer. Results: Low temperature plasma ashing removed more of the organic components and reduced fiber loss compared to the wet digestion method, making specimens so prepared more suitable for transmission electron microsocpy. Conclusions: The low temperature ashing technique is the most accurate method for analyzing asbestos in biological samples.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.114-118
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• 2011

Dye-Sensitized Solar Cells(DSSCs) consist of a titanium dioxide($TiO_2$) nano film of the photo electrode, dye molecules on the surface of the $TiO_2$ film, an electrolyte layer and a counter electrode. But two transparent conductive oxide(TCO) substrates are estimated to be about 60[%] of the total cost of the DSSCs. Currently novel TCO-less structures have been investigated in order to reduce the cost. In this study, we suggested a TCO-less DSSCs which has titanium double layer electrodes. Titanium double layer electrodes are formed by electron-beam evaporation method. Analytical instruments such as electrochemical impedance spectroscopy, scanning electron microscope were used to evaluate the TCO-less DSSCs. As a result, the proposed structure decreases energy conversion efficiency and short-circuit current density compared with the conventional DSSCs structure with FTO glass, while internal series impedance of TCO-less DSSCs using titanium double layer electrodes decreases by 27[%]. Consequently, the fill factor is improved by 28[%] more than that of the conventional structure.

• Analytical Science and Technology
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• v.6 no.2
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• pp.149-156
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• 1993

The formation of the graphite spherulites has been studied experimentally in the Ni-C liquid under high pressure and temperature. In the diamond-stable region the graphite spherulites were formed and grew stably. They were not the polycrystalline particles but the single crystals of the fullerene-type, respectively, grown spirally with much imperfection. And they were proved to be in a mixture state of carbon atoms with $sp^2$- and $sp^3$-bonding by an Auger electron spectroscope and a high resolution transmission electron microscope. As the pressure decreased from the diamond-stable region to the graphite-stable region, the shape of the graphite particles changed gradually from the sphere to the flaky shape. The formation of the graphite spherulites was attributed to the stable existence of the carbon atoms with $sp^3$ bonding in the diamond-stable region. The formation of the large fullerene-type graphite spherulites with much imperfection is well agreed with Kroto's prediction for growth of the giant fullerene.

• Journal of the Korean Society of Costume
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• v.58 no.9
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• pp.129-141
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• 2008

Jikgeum(woven with supplementary golden wefts) hyungbae(rank badge) of danryung(official uniform) excavated from Im Backryung'tomb($1498{\sim}1546$) of the Joseon dynasty($1392{\sim}1910$) at Goyang, Gyunggi-Do in 2007, was in a critical condition because of serious collapse of substrate in metal thread. For conservation of hyungbae, metal thread was examined by different scientific methods(Light Microscope, Scanning Electron Microscope and Energy Dispersive X-Rray Spectrometry(SEM-EDS), Fourier Transform Infrared Spectroscopy(FT-IR)). Analytical data showed that metal thread was gilt membrane strip composed of gold leaves and proteinaceous substrate which was probably parchment. To protect collapse of substrate, 1% solution of Paraloid B-72 was infilterated into substrate for consolidation of substrate and it was adhered to warp of fabric in hyungbae, before wet cleaning. After wet cleaning, the most of the gold leaves were restored, which was confirmed by both the examination with the naked eye and the microscopic examination.