• Economic and Environmental Geology
• /
• v.11 no.4
• /
• pp.183-186
• /
• 1978

Chemical analyses by electron microprobe indicate that the well-crystallized botryoidal coffinite with radial fibrous structure from the Woodrow Mine, New Mexico, U.S.A. has the formula ($U_{0.85}Ca_{0.14}$) $(Si_{0.86}P_{0.11}Al_{0.06}V_{0.02})O_2(OH)_4$, or ideally (U, Ca) (Si, P)$O_2(OH)_4$. It can be more simply designated as ideal formula $USiO_2(OH)_4$. This new formula is proposed for the coffinite.

• Transactions on Electrical and Electronic Materials
• /
• v.8 no.5
• /
• pp.211-214
• /
• 2007

Chemical and morphological changes of phenol formaldehyde-based photoresist after $O_2$ radiofrequency(RF) plasma treatment depending on exposure time and source power were investigated. It was found that etch rate of photoresist sharply increased after discharge turn on and reached a limit with increase in plasma exposure time. Contact angle measurements and X-ray photoelectron spectroscopy(XPS) analysis showed that the surface chemical structure become nearly constant after 15 sec of the treatment. Atomic force microprobe(AFM) measurements were shown that surface roughness was increased with plasma exposure time.

• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.E1
• /
• pp.44-53
• /
• 2008

This study was undertaken to measure the properties of individual mineral particles in an artificially saturated atmosphere at a vertical extinct mine with 430 m height. By synchrotron radiation X-ray fluorescence (SR-XRF) microprobe analysis, it was possible to determine the elemental composition of residual insoluble particles on individual cloud droplet replicas formed on the Collodion film. The XRF visualized elemental maps enabled us not only to presume the chemical mixing state of particles retained in cloud droplet, but also to estimate their source. Details about the individual mineral particles captured by artificial cloud droplets should be helpful to understand about the removal characteristics of dust particles such as interaction with clouds. Nearly all individual particles captured in cloud droplets are strongly enriched in Fe. Mass of Fe is ranged between 41 fg and 360 fg with average 112 fg. There is a good agreement between single particle analysis by SR-XRF and bulk particle analysis by PIXE.

• Proceedings of the KOSOMBE Conference
• /
• v.1989 no.05
• /
• pp.9-12
• /
• 1989

A preliminary study has been conducted to demonstrate the effect of laser heat treatment on Ni Ti alloy dental arch wires ($0.016"\;{\times}\;0.022"$ and $0.018"\;{\times}\;0.026"$, rectangular shape). Changes in mechanical and thermal properties and surface morphologies are investigated by using optical and scanning electron microscope (SEM), energy dispersive x-ray microprobe analysis(EDX), differential scanning calorimeter (DSC), and micro hardness tester. The results indicate that the laser can affect the thermal equilibrium state of the localized surface. Titanium rich surface film is formed by the laser treatment. The surface film and rapidly resolidified underlying structures show better chemical resistance than the matrix material. Phase transition temperatures which are related to shape recovery temperatures are changed after laser treatment. Hardness of resolidified area and heat affected zone are lower than before treatment.

• Journal of the Mineralogical Society of Korea
• /
• v.2 no.1
• /
• pp.37-46
• /
• 1989

X-ray, optical and electron microscope studies exhibit that the amphiboles in anorthositic saprolite from kaolin deposits, located in Suryun-myeon, Seongju-gun, Kyungsangbuk-do, have altered under weathering conditions to smectite, mixed-layer mineral, vermiculite and goethite. In early supergene alteration stage when rock structure is still preserved, smectite occurs as initial weathering product of amphibole. Further weathering leads to the formation of mixed-layer mineral, vermiculite and goethite as indicated by XRD and SEM studies. Scanning electron microscopy studies of amphibole show that the dissolution of amphibole proceeds by selective etching at the surface along weaker zones producing distinct etch pattern, The calcic amphiboles according to electron microprobe analyses, show leaching of the most mobile elements (Mg, Ca and Fe) during alteration.

• Journal of the Mineralogical Society of Korea
• /
• v.9 no.2
• /
• pp.93-101
• /
• 1996

Behavior of platinum group elements during crystallization within ore magma is of interest. In this study platinum is selected and its mineralogical and geochemical behavior in the presence of antimony and tellurium is investigated at 600$^{\circ}C$. High purity Pt, Sb, and Te are used as starting material and silica quartz tubings are as container. Rection products have been examined by use of ore microscope, X-ray diffractometer, electron microprobe analyser and micro-indentation hardness tester. stable phases at 600$^{\circ}C$ are platinum (Pt), Pt5Sb, Pt3Sb, PtSb, stumpflite (PtSb), geversite (PtSb), PtTe, Pt3Te4, Pt2Te3, moncheite (PtTe2), tellurantimony (Sb2Te3), and antimony (Sb). Geversite is the mineral showing the most significant extent of solid solution by up to 27 at% between Sb and Te elements. Isothermal section of 600$^{\circ}C$ is established in this study. It is noted that platinum cannot coexists with stumpflite or geversite under equilibrium condition, and stumpflite composition in equilibrium with geversite may be used as geothermometer.

• Mass Spectrometry Letters
• /
• v.7 no.3
• /
• pp.64-68
• /
• 2016

Scanning electron microscopy combined with thermal ionization mass spectrometry (SEM-TIMS) was used to determine the precise isotope ratios of ultra-trace levels of uranium contained in individual microparticles. An advanced multiple ion counter system consisting of three secondary ion multipliers and two compact discrete dynodes was used for complete simultaneous ion detection. For verification purposes, using TIMS with complete simultaneous measurement, isotopes were analyzed in 5 pg of uranium of a certified reference material. A microprobe in the SEM was used to transfer individual particles from a NUSIMEP-7 sample to TIMS filaments, which were then subjected to SEM-TIMS and complete simultaneous measurement. The excellent agreement in the resulting uranium isotope ratios with the certified NUSIMEP-7 values shows the validity of SEM-TIMS with complete simultaneous measurement for the analysis of uranium isotopes in individual particles. Further experimental study required for investigation of simultaneous measurement using the advanced multiple ion counter system is presented.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.3 no.1
• /
• pp.85-92
• /
• 1993

Large single crystals of olivine were grown by using image furnace(floating zone furnace)under controlled partial pressure of oxygen. The transparent crystals have maximum sizes 65mm in length by 7mm in diameter. When partial pressure of oxygen was decreased, the portion of secondary phases in crystals were increased so that it made crystals dark brown. The secondary phases were proved to be solid solution of Mg, Si, and Fe by electron microprobe analysis. Mg was major portion and the rest was minor.

• Journal of the Mineralogical Society of Korea
• /
• v.4 no.2
• /
• pp.141-146
• /
• 1991

Minerals of system Ag-Sb have been found in iead-zinc (-silver) ores from the Dongjeom and the Taebaeg ore deposits, which were formed at later stage of the Yeonhwa 1 mine mineralization. The Ag-Sb minerals are intergrown intimately with galena, pyrargyrite and alabandite. Their chemical compositions as determined by electron microprobe analyser show that they are chracterized by relatively high content of S, up to 5.89 atomic percent. Also the composition of the minerals may be separated into two: Ag3.89 Sb1.00-Ag7.19 Sb1.00 and Ag2.96 Sb1.00-Ag4.00 Sb1.00.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.8
• /
• pp.939-942
• /
• 1999

The tie lines delineating ion-exchange equilibria between NiFe2O4-NiCr2O4 spinel solid solution and Fe2O3-Cr2O3 corundum solid solution were determined at 900, 1000, and 1200 ℃ by electron microprobe and energy dispersive X-ray analysis of oxide phases, using the flux growth technique. Activities of the spinel components were calculated from the tie lines, assuming Temkin's ideal mixing in the corundum solid solution. The spinel phase could be expressed by a regular solution with negative deviations from ideality. The Gibbs free energies of mixing for spinel solid solution were discussed in terms of the cation distribution model, based on site preference energies and assuming random mixing on both tetrahedral and octahedral sites.