• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.21-22
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• 2000

Laser diagnostic method in a plasma display discharge cell was introduced. The information of electric field, potential and electron temperature et al. in the surface of plasma display panel can be measured using laser induced fluorescence spectroscopy. However, because of the very small discharge dimension of ${\sim}$ 100 ${\mu}m$, the measurement attempt has almost not been performed. In this paper, the direct measurement possibility of the parameters and the recent work of electric field measurement are demonstrated in the plasma display panel.

• International Journal of Computer Science & Network Security
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• v.24 no.6
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• pp.200-206
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• 2024

Laser induced breakdown spectroscopy (LIBS) technique has been used for the elemental composition of the soils. In this technique, a high energy laser pulse is focused on a sample to produce plasma. From the spectroscopic analysis of such plasma plume, we have determined the different elements present in the soil. This technique is effective and rapid for the qualitative and quantitative analysis of all type of samples. In this work a Q-switched Nd: YAG laser operating with its fundamental mode (1064 nm laser wavelength), 5 nanosecond pulse width, and 10 Hz repetition rate was focused on soil samples using 10 cm quartz lens. The emission spectra of soil consist of Iron (Fe), Calcium (Ca), Titanium (Ti), Silicon (Si), Aluminum (Al), Magnesium (Mg), Manganese (Mn), Potassium (K), Nickel (Ni), Chromium (Cr), Copper (Cu), Mercury (Hg), Barium (Ba), Vanadium (V), Lead (Pb), Nitrogen (N), Scandium (Sc), Hydrogen (H), Strontium (Sr), and Lithium (Li) with different finger-prints of the transition lines. The maximum intensity of the transition lines was observed close to the surface of the sample and it was decreased along the axial direction of the plasma expansion due to the thermalization and the recombination process. We have also determined the plasma parameters such as electron temperature and the electron number density of the plasma using Boltzmann's plot method as well as the Stark broadening of the transition lines respectively. The electron temperature is estimated at 14611 °K, whereas the electron number density i.e. 4.1 × 10¹⁶ cm^-3 lies close to the surface.

• Analytical Science and Technology
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• v.22 no.2
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• pp.141-147
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• 2009

A laser induced breakdown spectroscopy (LIBS) measurement was carried out to derive an optimized measurement condition with a high reproducibility and to grow a plasma sphere to 20 mm high under a 600 mtorr vacuum in order to improve an accuracy of measurement. The measurement of the plasma was taken at a 6.0 mm distance, in the direction of a plasma sphere, from a sample. This location belongs to the outer sphere region in the plasma. The calibration curve of 'Ni' and 'Cu' was acquired by the signal intensity ratio and the atomic ratio for the samples, and linear regression of 'Cu' was $R^2$=0.9886, and the linear regression of 'Ni' was $R^2$=0.9988. The accuracy of LIBS was improved pre-existence as the measurement error of 'Ni' was 0.78%.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.451-457
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• 2011

A short laser pulse irradiates a sample to create the highly energetic plasma that emits light of a specific wavelength peak according to the material. By identifying different peaks for the analyzed samples, its chemical composition can be rapidly determined. The LIBS (Laser-Induced Breakdown Spectroscopy) has great advantages as an elemental analyzer on board a space rover, namely real-time rapid analysis and stand-off detection. The LIBS signal intensity is remarkably increased by using double-pulse LIBS system for component analysis of lunar environments where the surrounding pressure is low. Also the angle of target is adjusted for replicating arbitrary shapes of the specimen.

• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.50-54
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• 2014

In this paper we studied the laser-induced crater depth, mass, and emission spectra of laser-ablated high-density polyethylene (HDPE) polymer using the laser-induced plasma spectroscopy (LIPS) technique. This study was performed using a Nd:YAG laser with 100 mJ energy and 7 ns pulse width, focused normal to the surface of the sample. The nanoscale change in ablated depth versus number of laser pulses was studied. By using scanning electron microscope (SEM) images, the crater depth and ablated mass were estimated. The LIPS spectral intensities were observed for major and minor elements with depth. The comparison between the LIPS results and SEM images showed that LIPS could be used to estimate the crater depth, which is of interest for some applications such as thin-film lithography measurements and online measurements of thickness in film deposition techniques.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.46-52
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• 2017

We quantitatively measured the mass transfer from friction surfaces, specifically brake pads and rotors, using laser plasma spectroscopy. Specifically, we modelled the mass transfer from the pad to the rotor and measured the elemental diffusion intensity distribution in the rotor material using laser plasma spectroscopy. The main elements measured were Cu, Ni, Ti, and Cr, and the distribution of these after transfer was measured as the ratio of the atomic peak and the ion peak of the plasma in the rotor exposed to friction and the surface composition of the rotor and the roughness, respectively. We measured and quantified the diffusion coefficient for each element through the mass transfer model and found that Cr obtained the largest diffusion coefficient (D) of the elements measured based on this system with a value of $1.9484{\times}10^{-15}m^2/s$.

• Transactions of the KSME C: Technology and Education
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• v.3 no.4
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• pp.291-297
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• 2015

As promising future energy source, hydrogen has been drawing much attention; however, it is easily leaked from the small gap in any storage container due to its find molecule size. In this study, Laser induced breakdown spectroscopy(LIBS) was used for hydrogen leak detection, and feasibility of the scheme was evaluated based on different way for plasma generation. Laser power of 295 mW was required for generating plasma on metal surface to measure hydrogen atomic emission while approximately 2.5 times higher laser power was needed for plasma formation directly in the hydrogen gas stream. It was shown that peak to base ratio increased linearly with increasing the concentration of hydrogen. It can be concluded that LIBS is a viable technique for hydrogen sensing when the concentration of hydrogen is less than 5%.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.140.1-140.1
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• 2015

Currently, As Plasma application is expanded to the industrial and medical industrial, Low temperature plasma characteristics became important. Especially in Medical industrial, Low temperature plasma directly adapted to human skin, so their plasma parameter is important. One of the plasma parameters is electron density, some kinds of method to measuring electron density are Thomson scattering spectroscopy and Millimeter-wave transmission measurement. But most methods is expensive to composed of experiment system. Heterodyne interferometer system is cheap and simple to setting up, So we tried to measuring electron density by Laser heterodyne interferometer. To measuring electron density at atmospheric pressure, we need to obtain the phase shift signal. And we use a heterodyne interferometer. Our guiding laser is Helium-Neon laser which generated 632 nm laser. We set up to chopper which can make a laser signal like a pulse. Chopper can make a 4 kHz chopping. We used Needle jet as Ne plasma sources. Interference pattern is changed by refractive index of electron density. As this refractive index change, phase shift was occurred. Electron density is changed from Townsend discharge's electron bombardment, so we observed phenomena and calculated phase shift. Finally, we measured electron density by refractive index and electron density relationship. The calculated electron density value is approximately 1015~1016 cm-3. And we studied electron density value with voltage.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.141-148
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• 2014

In this work, effects of plasma on different hardness of welding steel using laser-induced breakdown spectroscopy were investigated. The ratios of ionic to atomic spectrum peaks were related to its material hardness. The major spectrum peak (Fe) and minor spectrum peak (Mn) were considered as monitoring elements. The stronger repulse plasma was generated, the harder material it was. The ratios of ionic to atomic spectrum peaks increased with respect to the material hardness as well. The correlation of minor spectrum peaks was stronger than that of major spectrum peaks. However, the major spectrum peaks indicated a similar trend, which could be used to estimate the hardness, too. Based on this result, the method could be used as a non-contact remote measurement of material properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.234-234
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• 2008