• Transactions on Electrical and Electronic Materials
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• v.11 no.5
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• pp.226-229
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• 2010

Many methods exist that promote wound healing, including light therapy, which consists of light beams that assist the human body in treating and sterilizing wounds, as well as regenerating cells. Irradiation with specific wavelengths of either laser or LED light has been shown to induce beneficial proliferation of fibroblasts that, depending on the size of the wound, can be effective in promoting wound healing. The experiments in this study utilized 8 week old 250~300 g Male Sprague Dawley Rats (ILAR Code: NTacSam:SD) and included a non-irradiation group and a 525 nm green LED irradiation group (n of each group = 7). In experiments animals were allowed to rest for 24 hours after wounds had been excised, which was followed by non- irradiation or 525 nm green LED irradiation therapy one hour per day for 9 days. Immunohistochemical staining was conducted for cytokeratin in order to precisely measure the defect size. In addition, Masson's trichrome staining was utilized in order to compare levels of collagen between the 525 nm green LED irradiation group and the non-irradiation group. Animals exposed to 525 nm green LED irradiation (p<0.05) healed at a faster rate and had increased collagenosis compared with the non-irradiated control group. Thus, treatment with 525 nm green LED irradiation had a beneficial effect on wound healing and should be considered as a possible alternative to low power laser treatment.

• Laser Solutions
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• v.8 no.2
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• pp.7-12
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• 2005

The material processing of UV nanosecond pulse laser cannot be avoided the material shape change and contamination caused by interaction of base material and laser beam. Nowadays, ultra short pulse laser shorter than nanosecond pulse duration is used to overcome this problem. The advantages of this laser are no heat transfer, no splashing material, no left material to the adjacent material. Because of these characteristics, it is so suitable for micro material processing. The processing of sapphire wafer was done by UV 355nm, green 532nm, IR 1064nm. X-Y motorized stage is installed to investigate the proper laser beam irradiation speed and cycles. Also, laser beam fluence and peak power are calculated.

• Current Photovoltaic Research
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• v.11 no.3
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• pp.75-78
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• 2023

Recently, the installation of photovoltaic modules in urban areas has been increasing. In particular, the demand for solar modules installed in a limited space is increasing. However, since the crystalline silicon solar module's size is proportional to the solar cell's size, it is difficult to manufacture a module that can be installed in a limited area. In this study, we fabricated a solar module with a shingled design that can control horizontal and vertical width using a bi-directional laser scribing method. We fabricated a string cell with a width of 1/5 compared to the existing shingled design string cells using a bi-directional laser scribing method, and we fabricated a solar module by connecting three strings in parallel. Finally, we achieved a conversion power of 5.521 W at a 103 mm × 320 mm area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1847-1853
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• 2000

A computer simulation technique for 2-dimensional laser generated ultrasonic waves was developed for visualization and investigation of ultrasonic propagation in solids. The technique is similar to a finite difference method (FDM) and a mass-particle model method, but uses a new nodal calculation method based on fundamental consideration of an elastic wave equation. By this method, the propagation behavior oflaser generated ultrasonic wave in thermoelastic and ablation mode is visualized and shows good agreement with previous experimental result or the numerical analysis result by Green function.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.411-412
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• 2000

Si nanocrstallites on p-tyre (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser with the wavelength of 355, 532 and 1064 nm. The base vacuum in the chamber was down to $10^{-5}$ Torr and the pressure of the gas during deposition was varied from 1 to 3 Torr. After deposition, Si nanocrystallites have been annealed at $N_2$ gas. Nitrogen have been used as ambient gases. Strong blue and green luminescence from Si nanocrystallites has been observed in room temperature by photoluminescence and its peak energies shift to green when the wavelength is increased from 355-1064 nm

• Corrosion Science and Technology
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• v.10 no.4
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• pp.151-155
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• 2011

The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.11-20
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• 2002

The world at the end of the $20^{th}$ Century has become "blue" Indeed, this past decade has witnessed a "blue rush" towards the development of violet-blue-green light emitting diodes (LEDs) and laser diodes (LDs) based on wide bandgap III-Nitride semiconductors. And the hard work has culminated with, first, the demonstration of commercial high brightness blue and green LEDs and of commercial violet LDs, at the very end of this decade. Thanks to their extraordinary properties, these semiconductor materials have generated a plethora of activity in semiconductor science and technology. Novel approaches are explored daily to improve the current optoelectronics state-of-the-art. Such improvements will extend the usage and the efficiency of new light sources (e.g. white LEDs), support the rising information technology age (e.g. high density optical data storage), and enhance the environmental awareness capabilities of humans (ultraviolet and visible photon detectors and sensors). Such opportunities and many others will be reviewed in this presentation.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.19-22
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• 1998

In this work, nonlinear crystals are investigated as investigated ad future diode pumped host laser materials in the green. Optical properties( absorption, emission, secind harmonic generation, and continuous wave lader oscillation in the green) of the most relevant neodymium activeated oxide lader crystals{{{{ ({LiNbO }_{ 3}:MgO, YAI({BO }_{3})_{4} and {LaBGeO }_{ 5})}}}} are investigated and compared under similar experimental conditions

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.681-684
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• 2009

The turbidity of flow type samples has a nonlinear relation to brightness of laser scattered light, but the shape of images in laser scattered light is different from each turbidity samples. The turbidity measurement will be easy if it uses a pattern of images in laser scattered light. But the excessive analysis load comes from the turbidity measured by red, green, blue intensity (intensity) of all pixels of images in laser scattered light. Therefore the images in laser scattered light were divided by appropriate block to decrease excessive analysis load. The shape of divided images in laser scattered light was different from each turbidity sample. The real turbidity has a linear relation to turbidity measured by the artificial neural network learned with the intensity of divided images in laser scattered light and turbidity.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.14-22
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• 1995

This paper is concerned with the design of optimal surface heating patterns that result in focusing acoustic energy inside a subsurface target volume at a specified target time. The surface of the solid is heated by an incident laser beam which gives rise to shear and compressional waves propagating into the solid. The optimal heating design process aims to achieve the desired energy focusing at the target with minimal laser power densities and minimal system disturbance away from the target. The optimality conditions are secured via the conjugated gradient method and by the finite element method along with using the half-space Green's function matrix. Good quality energy focusing is achived with the optimal designs reflecting the high directivity of the photothermally generated shear wave patterns.