• 대한기계학회논문집B
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• 제29권4호
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• pp.453-459
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• 2005

In this paper, we are proposing a robust tool which is capable of measuring the size and elemental composition of submicron particles from twenty to several hundreds nanometers at the same time, i.e., named Single Particle Mass Spectrometer (SPMS). The home-made SPMS employs a laser ablation/multi-photon ionization method to tear a nanoparticle into the constituent elemental ions. One thing different from the conventional Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) is the power of the ionization laser. Much strong laser used in this work makes it possible to generate elemental ions rather than molecular ions from a nanoparticle. Also the use of high power laser may guarantee a complete ionization of a particle, which was confirmed by the existence of multiple charged ions. If a particle is evaporated/ionized completely and detected through electric field-free TOF tube without any loss, we can extract the original particle volume from the measured total ion numbers. Collecting a number of particles mass spectra, we get a database of size and elemental composition of nanoparticles, with which we may take a took into any kinds of chemical reaction occurring at nanoscale. Several issues related to size estimation by SPMS will be discussed.

• Asian Journal of Atmospheric Environment
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• 제5권1호
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• pp.56-63
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• 2011

Quantifying the solute composition of a cloud droplet (or a whole droplet) is an important task for understanding formation processes and heating/cooling rates. In this study, a combination of droplet fixation and SR-XRF microprobe analysis was used to visualize and quantify elements in a micro-scale droplet. In this study, we report the preliminary outcome of this experiment. A spherical micro-scale droplet was successfully solidified through exposure to ${\alpha}$-cyano-acrylate vapor without affecting its size or shape. An X-ray microprobe system equipped at the beam line 37XU of Super Photon ring 8 GeV (SPring-8) was applied to visualize and quantify the elemental composition in an individual micro-scale droplet. It was possible to reconstruct 2D elemental maps for the K and Cl contained in a microdroplet that was dispensed from the 10-ppm KCl standard solution. Multi-elemental peaks corresponding to X-ray energy were also successfully resolved. Further experiments to determine quantitative measures of elemental mass in individual droplets and high-resolution X-ray microtomography (i.e., 3D elemental distribution) are planned for the future.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.241-246
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• 2024

The study was carried out by numerical integration based on the diffraction properties and elemental composition. The elemental compositions of breast tissues in the literature were tested. The photon attenuation coefficients calculated using the recent elemental composition were found within 0.2-16% for adipose tissue and within 0.04-17% for glandular tissue with the experimental reference data. The attenuation coefficients of cancerous breast tissue calculated according to the elemental content previously measured in breast cancer patients were found within 0-17% with experimental data in the literature. The attenuation coefficients are of great interest to medical research. To calculate realistic attenuation coefficients, the characteristic coherent scatter, which is most intense at small angles, must be considered. For this reason, experimentally measured form factor data were reviewed, and the most compatible one with the theoretical form factor data produced in this study was used at low momentum transfer x (0 < x ≤ 8 nm^-1). The differential linear coherent scattering distributions were calculated for an energy value of 17.44 keV and compared with their experimental counterparts.

• 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.

• Asian Journal of Atmospheric Environment
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• 제5권3호
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• pp.196-203
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• 2011

The main aim of this study is to establish methods of morphological preservation and elemental quantification for individual snow crystals. Individual snow crystals were collected at a height of 20 m above ground level. To stabilize and preserve the original morphologies of the snow crystals, cyanoacrylate, which has been used to fix liquid droplets, was applied (Kasahara et al., 2000). Several different kinds of snow crystals (dendrite, sectored plate, quasi-sectored plate, and hexagonal plate) were successively stabilized using this method. The stabilized snow crystals were pretreated with acetone, and then the elemental components contained in a whole snow crystal were quantified with the Particle Induced X-ray Emission (PIXE) analytical technique. The snow crystal residual composition determined in the present study was dominated by sulfur and mineral components, and the elemental mass showed an apparent crystal size dependence, where the elemental mass gradually decreased as the crystal size increased.

• 한국대기환경학회지
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• 제13권4호
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• pp.307-317
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• 1997

Samples of fine particle $(d_P<2.5 \mum)$ were taken in Chongju area using a dichotomous sampler. The data set was collected on fifty-eight different days with 24 hour sampling period from October 27, 1995 through August 25, 1996. The samples were analyzed using a proton induced x-ray emission (PIXE) for Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, M, Fe, Ni, Cu, Zn, Br and Pb. Values of Fe, Ca, Si, Cu, K and Cl exhibit marked seasonal variations. Mean concentrations for this study had the following order S > Cl > Si > K > Al > Fe on fine particle. Concentrations of Ca, Si and Fe were higher during the spring season compared with any other season. These phenomena may be attributable to soil dust. Cl and K were higher in the winter, which may be explained by combustion of fossil fuel. Higher values for Cu and Zn in the Winter may be due to the combustion and incineration.

• 한국태양에너지학회 논문집
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• 제34권4호
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• pp.39-44
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• 2014

The elemental composition of electro-deposited black Cr solar selective coatings before and after heating in air by using secondary ion mass spectrometry (SIMS) was investigated for optical property analysis. In addition, black Cr selective coating exposed by solar radiation for 5 months was compared with heated sample. SIMS investigation shows that $OH^+$ bearing ions were related to a near surface region of CrOH and CrO compound. The optical degradation of this coating after heating at $500^{\circ}C$ reveals that diffusion of the Cu and Ni elements in substrate material, the chemical interactions adjacent to the interface, and the interface width broadening.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2006년도 춘계학술대회 논문집
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• pp.290-292
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• 2006

• Journal of Korean Society for Atmospheric Environment
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• 제20권E2호
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• pp.53-59
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• 2004

The roadway tunnels in urban areas give rise to problems such as a localized air pollution. Here, we report the results of a case study of an urban roadway tunnel measurement. The size-resolved particle sampling was carried out with a two 2-stage filter pack samplers and an Andersen impactor sampler at the center of Buk-Ak tunnel in November 2001. Particle Induced X-ray Emission (PIXE) was applied to determine the elemental composition of size-resolved particles divided into soluble and insoluble fractions. The Thermal/Optical Reflectance (TOR$^{(R)}$) method was also employed in analyzing of elemental carbon (EC) and organic carbon (OC). Mass concentrations of fine (< 1.2 ${\mu}{\textrm}{m}$) and coarse (> 1.2 ${\mu}{\textrm}{m}$) particles are 165 and 48 $\mu\textrm{g}$ m$^{-3}$ , respectively. Total elemental mass concentration (the sum of insoluble coarse, soluble coarse, insoluble fine, and soluble fine) is found to be 24$\mu\textrm{g}$ m$^{-3}$ and comprises only 11 % of total particle mass concentration. The concentrations of EC, OC, and mass show the clear dependency on particle size with the maximum between 0.1 and 0.43 ${\mu}{\textrm}{m}$ aerodynamic diameters. Total carbon (sum of EC and OC) accounts for approximately 70% of mass concentration.n.

• 한국대기환경학회지
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• 제21권6호
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• pp.699-708
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• 2005

To characterize the elemental composition of fine particles in urban area, $PM_{2.5}$ was collected by a 3-stage DRUM impactor at Gwangju during spring and summer. Time and size resolved concentrations for 19 trace elements were obtained by synchrotron X-Ray fluorescence analysis. Trace elements in summer were distributed in smaller size range compared to those in spring. Almost trace element concentrations in fine particles were highly increased during the Asian dust. In spring, soil elements such as Si, K, Ca, Ti and Fe had low enrichment factors indicating the dominant influence of soil dust. However, all elements had high enrichment factors in summer implying that these elements could be emitted from the anthropogenic sources. Factor analysis was conducted with the elemental composition data in order to identify anthropogenic sources of aerosols in urban area during spring and summer. Fine particles in spring have several sources such as soil dust originating from China continental region, coal and oil combustion, biomass burning, sea salt, ferrous and nonferrous metal sources. On the other hand, fine particles in summer were influenced by road dust, gasoline vehicle as well as coal and oil combustion, sea salt, ferrous and nonferrous metal sources.