• Analytical Science and Technology
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• v.32 no.4
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• pp.121-130
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• 2019

Alumina is one of the most important ceramic materials because of its useful physical and chemical properties. Recently, high-purity alumina has been used in various industrial fields. This leads to increasing demand for reliable elemental analysis of impurities in alumina samples. However, the chemical inertness of alumina makes the sample preparation for conventional elemental analysis a tremendously difficult task. Herein, we demonstrated the feasibility of laser ablation for effective sampling of alumina powder. Laser ablation performs sampling rapidly without any chemical reagents and also allows simultaneous optical emission spectroscopy and mass spectrometry analyses. For six alumina samples including certified reference materials and commercial products, laser-induced breakdown spectroscopy (LIBS) and laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) analyses were performed simultaneously based on a common laser ablation sampling. LIBS was found to be useful to quantify alkali and alkaline earth metals with limits-of-detection (LODs) around 1 ppm. LA-ICP-MS could quantify transition metals such as Ti, Cu, Zn, and Zr with LODs in the range from a few tens to hundreds ppb.

• Particle and aerosol research
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• v.12 no.3
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• pp.57-63
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• 2016

The laser-induced breakdown spectroscopy (LIBS) has been used for rapid detection of elemental compositions of various materials in multi-media (solid, liquid, gas, and aerosols). In this study, the aerosol-LIBS has been developed for real-time monitoring of process-induced particles produced during the semiconductor manufacturing. The developed aerosol-LIBS mainly consists of laser, optics, spectrometer, and aerosol chamber. A new aerosol chamber was constructed for the aerosol-LIBS to be applied for various semiconductor manufacturing process, including exhaust tubes, and low pressure and high temperature chamber. The aerosol-LIBS was evaluated by using laboratory generated aerosols for detection of various elements. As a result, P, Fe, Mg, Cu, Co, Ni, Ca, Na, and K emission lines were successfully detected by the aerosol-LIBS. Further evaluation of the aerosol-LIBS is being conducted.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.105-109
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• 2015

This paper presents the results of an experimental analysis of the high-power laser (HPL)-induced damage to a complementary metal-oxide semiconductor (CMOS) image sensor. Although the laser-induced damages to metallic materials have been sufficiently investigated, the damages to electric-optic imaging systems, which are very sensitive to HPLs, have not been studied in detail. In this study, we experimentally analyzed the HPL-induced damages to a CMOS image sensor. A near-infrared continuous-wave (CW) fiber laser was used as the laser source. The influences of the irradiance and irradiation time on the permanent damages to a CMOS image sensor, such as the color error and breakdown, were investigated. The experimental results showed that the color error occurred first, and then the breakdown occurred with an increase in the irradiance and irradiation time. In particular, these damages were more affected by the irradiance than the irradiation time.

• Biomedical Science Letters
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• v.13 no.3
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• pp.223-230
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• 2007

Low power laser and neuromuscular electrical stimulation have been utilized in many clinical applications for the treatment of musculoskeletal lesion. This study was to investigate the effects of low power He-Ne IR laser and neuromuscular electrical stimulation on the change of the serum biochemical components in experimentally induced muscle injured rats. The twenty Sprague-Dawley male rats were randomly assigned to the 4 groups: the normal group (n=5), the control group (n=5), the low power laser irradiation group (LLI) (n=5) and the neuromuscular electrical stimulation group (NMES) (n=5). The experimentally induced muscle injury was induced by the subcutaneous injection of a 0.1 ml Freund's Complete Adjuvant into the right hind paw and calf muscles in control, LLI and NMES groups. The LLI group was irradiated with He-Ne IR laser for 5 minutes every day during 10 days. Also, the NMES group was electrically stimulated 15 minutes every day during 10 days. The normal and control groups were not received with any therapeutic intervention. The authors performed tests which were the concentration of the serum biochemical components to detect the effects of therapeutic interventions. The results were as follows: 1. The level of the aspartate aminotransferase (AST) was significantly decreased in the LLI and NMES groups compare to the control group. 2. The level of the serum lactate dehydrogenase (LDH) was significantly decreased in the LLI and NMES groups compare to the control group. 3. The level of the serum creatine kinase (CK) was significantly decreased in the LLI and NMES groups compare to the control group. From the results, we could come to the conclusion that low power laser and neuromuscular electrical stimulation could be accelerating healing processes of skeletal muscle injury and further clinical work will be required.

• Current Photovoltaic Research
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• v.4 no.2
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• pp.54-58
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• 2016

Laser-doped selective emitter process requires dopant source deposition, spin-on-glass, and is able to form selective emitter through SiNx layer by laser irradiation on desired locations. However, after laser doping process, the remaining dopant layer needs to be washed out. Laser-induced melting of pre-deposited impurity doping is a precise selective doping method minimizing addition of process steps. In this study, we introduce a novel scheme for fabricating highly efficient selective emitter solar cell by laser doping. During this process, laser induced damage induces front contact destabilization due to the hindrance of silver nucleation even though laser doping has a potential of commercialization with simple process concept. When the laser induced damage is effectively removed using solution etch back process, the disadvantage of laser doping was effectively removed. The devices fabricated using laser doping scheme power conversion efficiency was significantly improved about 1% abs. after removal the laser damages.

• Korean Journal of Acupuncture
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• v.34 no.1
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• pp.56-69
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• 2017

Objectives : The purpose of this study is to compare the effects of laser acupuncture to the 532 nm on the five transport points with the heart meridian for treatment to hypertensive disease in rats with L-NAME induced hypertensive. Methods : Hypertensive was induced by L-NAME for 3 weeks. The laser acupuncture therapy on the five transport points of heart meridian(Laser Well Point-HT9, Laser Brook Point-HT8. Laser Stream Point-HT7, Laser River Point-HT4 and Laser Sea Point-HT3) was treated twice a week for 5 times. The hypertensive was measured using a cardiac hypertrophy, atherogenic index, TG/HDL-cholesterol ratio, TCHO, HDLC, TG, AST, ALT, antioxidative effectiveness and glutathione peroxidase quality of hypertensive rats induced by L-NAME. Results : Blood pressure were decreased significantly after the laser acupuncture of Well, Brook and Sea Point groups. Cardiac hypertrophy were decreased at the laser acupuncture of Brook and Stream Point groups. Athrogenic index was decreased at the laser acupuncture of Well, Stream, River and Sea Point groups. TG/HDL-cholesterol ratio was decreased at the laser acupuncture of all groups. Total cholesterol was decreased significantly at the laser acupuncture of Well Point group. High density lipoprotein cholesterol and total cholesterol were decreased significantly at the laser acupuncture of Well, Stream and River Point groups. Triglyceride was decreased significantly at the laser acupuncture of Stream Point group. Cu/Zn-Superoxide Dismutase (Cu/Zn-SOD) and glutathione peroxidase(GPX) were increased significantly at the laser acupuncture of Well Point group. Conclusions : The laser acupuncture treatment in five transport points of the Heart Meridian was effective for lowering blood pressure, cardiac hypertrophy, Atherogenic index and HTR, and for enhancing antioxidant activity.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.11-13
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• 2001

• Proceedings of the Korean Society of Laser Processing Conference
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• 2002.05a
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• pp.21-24
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• 2002

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.11a
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• pp.37-41
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• 2001

• Proceedings of the Korean Society of Laser Processing Conference
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• 1998.11a
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• pp.10-13
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• 1998