• Economic and Environmental Geology
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• v.46 no.6
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• pp.495-508
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• 2013

Recently, stable isotopes (${\delta}^{18}O$ and ${\delta}D$) of water are increasingly analyzed using laser-based technologies. These methods have advantages over Isotope Ratio Mass Spectrometry (IRMS) in that they can be used for in-situ measurements and require much less maintenance and preparation work. Two types of laser-based methods are currently available, which have different analytical principles; OA-ICOS (off-axis integrated cavity output spectroscopy) and WS-CRDS (wavelength-scanned cavity ring-down spectroscopy). In the WS-CRDS instrument, water is vaporized at controlled environment and transferred to an optical cavity by nitrogen carrier gas, and stable isotopic compositions of water vapor are measured using the degree of absorbance of specific wavelengths and the ratios of attenuation time of the laser intensity with the sensitivity of ppb to tens of ppt level. In this study, we introduce the principle of the WS-CRDS technology and the performance results including stability and comparisons with Isotope Ratio Mass Spectrometry (IRMS) and suggest possible applications of various topics in isotope hydrology.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.161-170
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• 2022

The effect of oxidation time on the characteristics and mechanical properties of spent nuclear fuel cladding was investigated using Raman spectroscopy, tube rupture test, and tensile test. As oxidation time increased, the Raman peak associated with the tetragonal zirconium oxide phase diminished and merged with the Raman peak associated with the monoclinic zirconium oxide phase near 333 cm^-1. Additionally, the other tetragonal zirconium oxide phase peak at 380 cm^-1 decreased after 100 d of oxidation, whereas the zirconium monoclinic oxide peak became the dominant peak. The oxidation time had no effect on the tube rupture pressure of the oxidized zirconium alloy tube. However, the yield and tensile stresses of the oxidized nuclear fuel cladding tube decreased after 100 d of oxidation. The results of the scanning electron microscopy and transmission electron microscopy were represented with the in-situ Raman analysis result for the oxide characteristics generated on the cladding of spent nuclear fuel.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1206-1209
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• 2007

Both PM-OLEDs and AM-OLEDs are now in production. However, manufacturers are still concerned about life-time, voltage drift, operating voltage and efficiency in order to develop larger displays. Most material suppliers seem to be focussing on emitters and the benefits of introducing suitable charge transporters have been largely unexplored. OLED-T has developed a novel organic electron injector (Trade Name: EI-101) which evaporates at a very low temperature of $300^{\circ}C$ as opposed to the conventional LiF which requires $580^{\circ}C$. EI-101 has been found to increase the lifetime by up to 12%, reduce the voltage drift by up to 61% and increase the efficiency by up to 15%. The material can be handled in air and in situ Q-mass spectroscopy on extended thermal evaporation has confirmed its high stability for use in mass production.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.4
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• pp.96-103
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• 2020

A new NMR method to monitor solvent-localized NMR signals in the two-phase liquid system is suggested. This method based on intermolecular single-quantum coherence (iSQC). Here, we exploited the feature of the local action of distant dipolar field (DDF) effect in order to filter out specific NMR signals dissolved in different solvents. This solvent specific iSQC spectroscopy was carried out on a model two-phase liquid system (D-glucose in water/palmitic acid in chloroform), and showed solvent-localized NMR signals. We believe our approaches might be useful in metabolic analysis such as two-phase liquid extraction scheme for labile chemical species.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.25-25
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• 2010

The spectroscopy over a region from 3 to 17 ${\mu}m$ based on the tuneable diode lasers (TDLAS) is the most powerful technique for in situ studies of the diagnostics of small molecules. The increasing interest in small molecules especially containing carbon, oxygen, hydrogen, and fluorine containing ones can be fulfilled by TDLAS at 0.0001 cm-1 resolution, because most of these compounds are infrared active. TDLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which can be employed for the time dependent studies in sub micro second scale. Information about gas temperature and population densities can also be derived from TDLAS measurements. Collisional energy transfer between the small molecules can be studied with TDLAS. Also, a variety of free radicals and molecular ions have been detected by TDLAS. Since plasmas with molecular feed gases are used in many applications, there are new applications in industrial field. Recently, the development of quantum cascade lasers (QCLs) offers an attractive new option for TDLAS.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.343-343
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• 2011

ZnO has been introduced as one of the good candidates for next generation opto-electronics. Recently, ZnO is known to be suitable for the transparent electrode in organic solar cells and light emitting devices. The contact with n-type organic material has been studied due to the n-type properties of ZnO. However, the surface of ZnO has shown different electronic property with respect to its surface orientation. Therefore, it is presumed that there are differences in the interfacial electronic structures between organic materials and ZnO with different orientation. Therefore, it is required to classify the interfacial electronic structures according to the surface orientation of ZnO. In this study, we measured the interfacial electronic structures between the ZnO substrate having various orientations and a typical n-type organic material, tris-(8-hydroxyquinoline) aluminum (Alq3). In-situ x-ray and ultraviolet photoelectron spectroscopy measurements revealed the interfacial electronic structures. We found the changes in the electronic structures with respect to the orientation of ZnO substrate and it could be used to improve the contact between ZnO and Alq3.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.295-298
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• 2013

Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.

• Journal of Powder Materials
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• v.22 no.5
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• pp.309-314
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• 2015

Tungsten trioxide thin films are successfully synthesized by a sol-gel method using tungsten hexachloride as precursors. The structural, chemical, and optical properties of the prepared films are characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry. The electrochemical and electrochromic properties of the films before and after heat treatment are also investigated by cyclic voltammetry, chronoamperometry, and in situ transmittance measurement system. Compared to as-prepared films, heat-treated tungsten trioxide thin films exhibit a higher electrochemical reversibility of 0.81 and superior coloration efficiency of $65.7cm^2/C$, which implies that heat treatment at an appropriate temperature is a crucial process in a sol-gel method for having a better electrochromic performance.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2005.05a
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• pp.50-57
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• 2005

Although the bulk composition of materials is one of the major considerations in extractive metallurgy and environmental science, surface composition and topography (edges and dislocations are preferred sites for physicochemical reactions) control surface reactivity, and consequently play a major role in determining metallurgical phenomena and pollution by heavy metals and organics. An understanding of interaction mechanisms of different chemical species with the mineral surface in an aqueous media is very important in natural environment and metallurgical processing. X-ray photoelectron spectroscopy (XPS) has been used as an ex-situ analytical technique, but the material to be analyzed can be any size from $100{\mu}m$ up to about 1 cm. It can also measure mixed solids powders, but it is impossible to ascertain the original source of resulting x-ray signals where they were emitted from, since it radiates and scans the macro sample surface area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.64-64
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• 2009

As the advanced packaging technology developing, Copper electro-plating processing has be wildly utilized in the semiconductor interconnect technique. Chemical solution monitoring methods, including PH and gravity measurement exist in industry, but economical and practical real-time monitoring has not been achieved yet. Red-green-blue (RGB) color sensor can successfully monitor the condition of $CuSO_4$ solution during electric copper plating process. Comparing the intensity variations of the RGB data and optical spectroscopy data, strong correlation between two in-situ sensors have shown.