• Title/Summary/Keyword: Chemical laser

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The Application of Time-Resolved Laser Induced Fluorescence Spectroscopy in the Complexation Studies of Eu(III) and Cm(III) with Humic Substances

  • Joong Gill Choi;Oum Ka Won;Chang Yeoul Choi;Hichung Moon;Hyun Sang Shin;Park, Seung Min;Paul Joe Chong
    • Bulletin of the Korean Chemical Society
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    • v.14 no.1
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    • pp.72-78
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    • 1993

  • The application of time-resolved laser induced fluorescence spectroscopy (TRLIF) to the complexation studies of Eu(III) and Cm(III) with humic substances is described. Using this method, three different spectroscopic characteristics(excitation spectra, emission spectra, and lifetimes) of these aquo ions and their complexes can be directly measured. By observing shifts in the wavelength and changes in the lifetime and intensities of the fluorescence emission, the information on the complexation behavior of humic substances with these trivalent metal cations in an aqueous solution, as well as energy transfer mechanisms, can be obtained. In addition, this method allows precise spectroscopic quantification of the complexation processes at very low concentrations of both components.

  • https://doi.org/10.5012/bkcs.1993.14.1.72 인용 PDF

Comparative Toxicity Studies of Ultra-Pure Ag, Au, Co, and Cu Nanoparticles Generated by Laser Ablation in Biocompatible Aqueous Solution

  • Kim, Yea-Seul;Kim, Kuk-Ki;Shin, Seon-Mi;Park, Seung-Min;Hah, Sang-Soo
    • Bulletin of the Korean Chemical Society
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    • v.33 no.10
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    • pp.3265-3268
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    • 2012

  • Nanoparticles (NPs) are increasingly used in consumer products, which have aroused many concerns and debates regarding their fate in biological systems from a point of their safety/toxicity. Although a number of studies on the biological effects of NPs have been published, these are often complicated by the possible toxicity of conventional NPs, caused by contamination with chemical precursors or additives during their synthesis and/or purification procedures. To explicitly understand the toxicity basis of NPs, it is necessary to directly address a main problem related to their intrinsic/inherent toxicity and/or incompatibility with biological objects. The present study is designed to take advantage of a novel laser-assisted method called laser ablation to generate Ag, Au, Co, and Cu NPs in biocompatible aqueous solution, and to evaluate the toxicity of the resulting ultra-pure NPs. Our results show that the ultra-pure NPs with nascent surfaces possess moderate cytotoxicity to human cells in a cell-dependent manner.

  • https://doi.org/10.5012/bkcs.2012.33.10.3265 인용 PDF KSCI

Output characteristics of a continuous wave deuterium fluoride chemical laser (연속발진 불화중수소 화학 레이저 출력특성)

  • 이정환;박병서;김재기
    • Korean Journal of Optics and Photonics
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    • v.13 no.1
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    • pp.65-69
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    • 2002

  • A continuous wave deuterium fluoride (DF) chemical laser was designed and manufactured, and we have achieved DF laser beam generation with the maximum output power of 101 W. The gain medium is vibration-rotationally excited DF molecules produced by F+D$_2$ cold reaction through supersonic diffusion mixing in an optical cavity. F atoms are produced in a combustor by F$_2$+ H$_2$ reaction and injected into the cavity through a supersonic nozzle. The optimal chemical efficiency was measured to be 5.12% and specific power to be 96.5 J/g.

  • https://doi.org/10.3807/KJOP.2002.13.1.065 인용 PDF KSCI