• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.213-217
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• 2005

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely This highlights the importance of measuring density distribution in plasma electric discharge mechanism study The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1 {\to} 6^3P_2$ ) were larger than 404.8nm ($6^3S_1 {\to} 6^3P_1$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• The Journal of the Korean dental association
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• v.52 no.12
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• pp.783-794
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• 2014

Since the introduction of non-thermal atmospheric pressure plasma in the field of the dentistry, numerous applications have been investigated. Especially with its advantages over existing vacuum plasma in terms of portability, low cost, and non-thermal damage, it can be directly applied in the oral cavity, giving number of potentials for dental application. First, possible application of non-thermal atmospheric pressure plasma in the field of dentistry is relation to dental caries and periodontal diseases. Teeth and alveolar bones are one of the strongest bony structures in our body, but it cannot be regenerated when they are damaged by dental caries or periodontal disease. Hence many studies to prevent such diseases have been carried out, though no perfect solution has been found yet. With recent studies of modifying surfaces through non-thermal atmospheric pressure application that can prevent attachment of bacteria, or studies on bactericidal effects of non-thermal atmospheric pressure plasma can be applied here to prevent oral pathogen and 'biofilm' attachment to the surface of teeth or directly eliminate the dental caries/periodontal disease causing germs. Secondly, non-thermal atmospheric pressure application will be useful on the surface of dental implant. It is well known that the success of dental implant surgery depends on the process known as 'osseointegration' that result from osteoblast attachment, proliferation and differentiation. As the application of non-thermal atmospheric pressure plasma on the surface of dental implant just before its introduction by the chair-side of dental surgery. Despite its long history, the generation of non-thermal atmospheric pressure plasma has been greatly increased with its application in dentistry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.27-32
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• 2006

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely. This highlights the importance of measuring density distribution in plasma electric discharge mechanism study. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength change, and also confirmed that the largest fluorcscent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1{\rightarrow}6^3P_2$) were larger than 404.8nm ($6^3S_1{\rightarrow}6^3P_2$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2586-2591
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• 2022

In the present work, we have irradiated the DI-BSCCO superconducting tapes with the 100 keV deuterium ions to investigate the effect of ion irradiation on their critical current (Ic). The damage simulations are carried out using the binary collision approximation method to get the spatial distribution and depth profile of the damage events in the high temperature superconducting (HTS) tape. The point defects are formed near the surface of the HTS tape. These point defects change the vortex profile in the superconducting tape. Due to the long-range interaction of vortices with each other, the Ic of the tape degrades at the 77 K and self magnetic field. The radiation dose of 2.90 MGy degrades the 44% critical current of the tape. The results of the displacement per atom (dpa) and dose deposited by the deuterium ions are used to fit an empirical relation for predicting the degradation of the Ic of the tape. We include the dpa, dose and columnar defect terms produced by the incident particles in the empirical relation. The fitted empirical relation predicts that light ion irradiation degrades the Ic in the DI-BSCCO tape at the self field. This empirical relation can also be used in neutron irradiation to predict the lifetime of the DI-BSCCO tape. The change in the Ic of the DI-BSCCO tape due to deuterium irradiation is compared with the other second-generation HTS tape irradiated with energetic radiation.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.1
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• pp.75-79
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• 1999

We have studied electrical properties of polyimide for the next generation interlayer low dielectric during plasma etching. Dielectric constant of polyimide exposed to Cl-based plasma, which is used in aluminum etching, increased, while that of polyimide exposed to $SF_{6}$ plasma decreased. The results are related to fluorine or chlorine bonds as examined by FTIR ana XPS analyses. So, we expect that Cl-based 1)miasma etching of aluminum followed by $SF_{6}$ plasma exposure results in the prevention of post-etch corrosion and decrease of dielectric constant.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.240.2-240.2
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• 2014

Characteristics of pulse-discharged plasma in liquid and its biological applications to proteins are investigated by making use of high voltage Marx generator. The Marx generator has been consisted of 5 stages, where each charging capacitor is $0.5{\mu}F$ to generate a high voltage pulse with rising time of $1{\mu}s$. We have applied an input voltage of 6 kV to the each capacitor of $0.5{\mu}F$. The high voltage pulsed plasma has been generated inside a polycarbonate tube by a single-shot operation, where the breakdown voltage is measured to be 7 kV, current of 1.2 kA, and pulse width of ${\sim}1{\mu}s$ between the two electrodes of anode-cathode made of stainless steel, which are immersed into the liquids. For the investigation of the influence of pulsed plasma on biomolcules, we have focused on the amino acids, DNA, proteins, cell and cholesterol.

• Applied Science and Convergence Technology
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• v.25 no.1
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• pp.15-18
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• 2016

Study investigated the optimal anodizing conditions for fabricating an oxide film that produces less contamination in a corrosive plasma environment, using oxalic acid and tartaric acid. Oxide films were produced using sulfuric acid, oxalic acid, and tartaric acid electrolyte mixtures with various mole ratios. The oxide film made by adding 0.05M tartaric acid to 0.3M oxalic acid showed higher breakdown voltage and lower leakage current. Additionally, contamination particles were reduced during plasma etching, thus demonstrates that this mixture presented optimal conditions. However, higher tartaric acid content (0.1 M, 0.15 M) led to lower breakdown voltages and higher leakage currents. Also, it resulted in more cracking during thermal shock tests as well as the generation of more contamination particles during plasma processing.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.915-923
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• 2013

Decomposition of non-biodegradable contaminants such as phenol contained in water was investigated using a dielectric barrier discharge (DBD) plasma reactor in the aqueous solutions with continuous oxygen bubbling. Effects of various parameters on the removal of phenol in aqueous solution with high-voltage streamer discharge plasma are studied. In order to choose plasma gas, gas of three types (argon, air, oxygen) were investigated. After the selection of gas, effects of 1st voltage (80 ~ 220 V), oxygen flow rate (2 ~ 7 L/min), pH (3 ~ 11), and initial phenol concentration (12.5 ~ 100.0 mg/L) on phenol degradation and change of $UV_{254}$ absorbance were investigated. Absorbance of $UV_{254}$ can be used as an indirect indicator of phenol degradation and the generation and disappearance of the non-biodegradable organic compounds. Removal of phenol and COD were found to follow pseudo first-order kinetics. The removal rate constants for phenol and COD of phenol were $5.204{\times}10^{-1}min^{-1}$ and $3.26{\times}10^{-2}min^{-1}$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.220-223
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• 2004

Inductively coupled plasma is commonly used for electrodeless lamp due to its ease of plasma generation. Optical characteristics significantly depend on the RF power and gas pressure of the plasma. This paper describes the measurement of luminance as a function of RF power and gas pressure with a goal of finding optimal operating conditions of the electrodeless lamp. The gas pressure was varied from 10[mTorr] to 300[mTorr] or 500[mTorr] and the RF power was varied from 10[W] to 200[W]. It was found that the luminance tends to be decreased when argon and neon pressure is increased, and the luminance is increased as RF power is increased. It was also found that the luminance per unit RF power is high when the argon and neon pressure is low and when the RF power is in the range of $30[W]{\sim}40[W]$ or 10[W].

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.589-596
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• 2008

Performance of a pulsed heat source high temperature inert gas plasma MHD electrical power generator, which can be one of the candidates of space-based laser-to-electrical power converter, is examined by a time dependent two dimensional numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally heated to about $10^4K$ pulsed-likely within short time(${\sim}1{\mu}s$) in a stagnant energy input volume, and the energy of high temperature inert gas is converted to the electricity with the medium of pure inert gas plasma without seeding. The numerical simulation results show that an enthalpy extraction ratio(=electrical output energy/pulsed heat energy) of several tens of % can be achieved, which is the same level as the conventional seeded non-equilibrium plasma MHD generator. Although there still exist many phenomena to be clarified and many problems to be overcome in order to realize the system, the pulsed heat source high temperature inert gas MHD generator is surely worth examining in more detail.