• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.321-328
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• 2011

Various methods have been investigated to increase photon density in soft tissue, an important factor in low-level laser therapy. Previously we developed a compression-controlled low-level laser probe (CCLLP) utilizing mechanical negative compression, and experimentally verified its efficacy. In this study, we used Bezier curves to numerically simulate the skin deformation and photon density variation generated by the CCLLP. In addition, we numerically modeled changes in optical coefficients due to skin deformation using a linearization technique with appropriate parameterization. The simulated results were consistent with both human in vivo and porcine ex vivo experimental results, confirming the efficacy of the CCLLP.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.173-179
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• 2003

In optical storage device system, there are several research topics to increase its recording density. The main idea is reducing wave length of laser diode and magnifying the number of numerical aperture (NA). In conventional optical system NA cannot be over the unity in the air because of its diffraction limit. But it is possible to overcome its limitation of unity in near field using Solid Immersion Lens. In this work, the mathematical Solid Immersion Lens (SIL) design process was illustrated by using near field theory. Also, numerical SIL design parameters were calculated by means of CODE V. Through the work, we propose the new type of SIL for high density optical recording systems.

• Journal of Pharmacopuncture
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• v.4 no.1
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• pp.125-139
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• 2001

In order to study the effects of bee venom herbal acupuncture on the neurotransmitters of the rat brain cortex, herbal acupuncture with the bee venom group and normal saline group was performed bilaterally on the point corresponding to LI 4 of the rat. The average optical density of the neurotransmitters from the cerebral cortex was analyzed 30 minutes after the herbal acupuncture with immunohistochemical methods. The results were as follows: 1. The density of NADPH-diaphorase in the bee venom group was increased significantly at the motor cortex, visual cortex, auditory cortex, cingulate cortex, retrosplenial cortex, and perirhinal cortex, compared to the normal saline group. 2. The average optical density of vasoactive intestinal peptide in the bee venom group had significant changes at the insular cortex, retrosplenial cortex, and perirhinal cortex, compared to the normal saline group. 3. The average optical density of neuropeptide-Y in the bee venom group increased significantly at the visual cortex and cingulate cortex, compared to the normal saline group.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.189-195
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• 2003

The objective of this study is to improve the optical sensitivity of laser fluorescence for detection of incipient enamel caries. An incipient carious lesion was formed in various stages by placing an enamel specimen of a bovine tooth in STPP demineralization solution. After measuring the optical density of the lesion surface by laser fluorescence induced by argon laser and various alter of yellow(500-520nm), amber(520-540nm), orange(540-560nm), and red(560-580nm), the specimen was cut vertically to measure the depth of the lesion using a polarizing microscope. SAS statistical program was used to analyze the relationship between the optical density of the lesion suface and the depth of the lesion. The results were as follows: 1. The optical density of early carious lesion, measured by laser fluorescence with amber and orange filter, and lesion depth observed by polarizing microscope, were increased as demineralization time increased. 2. The correlation coefficient between optical density of the lesion surface and the histological depth of the lesion was the highest in orange filter(r=0.49), followed by amber(r=0.32), yellow(r=0.13) and red(0.01). 3. Regression analysis showed that the most linear relationship between the optical density and the lesion depth was existed in orange filter group. In regard above results, laser fluorescence could be considered to be reliable for optical diagnosis of dental caries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.178-178
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• 2009

High-density optical information storing equipment, which is using Blu-ray, is the next generation information storing equipment that has about form six times to thirty-five times capacities. and high-density optical information storing equipment uses high NA(Numerical Aperture) aspheric glass objective lens as optical pick-up equipment to record and recognize high-density date. Generally this objective lens is developed and produced through a way of GMP(Glass Molding Press) that uses molding core that is performde by Ultra precision grinding, but grinding performing that has high-accuracy is very difficult because objective lens form is high NA. In this research, we preformed Ultra precision turning, using single crystal diamond bite, about WC(Co 0.5%), sintering brittleness material that is used molding core's material for GMP. and we confirmed aspheric glass lens compression of deformities molding core's Ultra precision turning possibility by measuring surface roughness(Ra) and processing surface's condition.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.17-22
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• 2001

Purpose: To compare the film density of Insight dental X-ray film (Eastman Kodak Co., Rochester, NY, USA) with that of Ektaspeed Plus film (Eastman Kodak) under manual and automatic processing conditions. Materials and Methods : Insight and Ektaspeed Plus films were exposed at three different exposure conditions with an aluminum step wedge on the films under the three different exposure times. The exposed films were processed by both manual and automatic ways. The Base plus fog density and the optical density made by exposing step wedge were calculated using a digital densitometer (model 07-443, Victoreen Inc, Cleveland, Ohio, USA). The optical densities of the Insight and Ektaspeed film versus thickness of alumimun wedge at the same exposure time were plotted on the graphs. Statistical analyses were applied for comparing the optical densities of the two films. Results: The film density of both Insight films and Ektaspeed Plus films under automatic processing condition was significantly higher over the manual processing. The film density of Insight films was significantly higher than that of Ektaspeed Plus films on both automatic and manual processing conditions. Conclusion: The radiation exposure time can be reduced when using Insight over Ektaspeed Plus film. To take the full advantage of reducing exposure time, Insight film should be processed automatically.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.336-339
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• 1999

In this paper, we describe the accommodation of the PRML technique for the high speed and high density optical disk systems, which has been very effective in the high density HDD systems. To make the PRML technique adequate for the optical disk systems, the channel modeling and the simulation are performed. Finally, the architecture has been designed and realized into an ASIC. We have focused on the differences of PRML architecture between the HDD system and the optical disk system, and the digital realization of the PLL which has been realized with analog circuits.

• Journal of Radiation Protection and Research
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• v.10 no.1
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• pp.64-66
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• 1985

A methylene blue-PVA system has been tested as a krad range dosimeter. Mb dye films were fabricated by casting PVA in solution with the methylene blue. In the air the system was irradiated by X-ray and the decolorisation of the dye film was found to remain unchanged for sufficiently long time. The radiation response on optical density at 670 nm in the Mb-PVA system shows a quite good linearity and reproducibility in the krad range.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.70-71
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• 2003

An FGC(focusing grating coupler), an optical integrated device converging light to a certain point, was designed and fabricated to operate at a blue wavelength for use of high-density optical micro-disk storage.

• Proceedings of the Optical Society of Korea Conference
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• 1995.06a
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• pp.138-148
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• 1995

A reduced description of the dynamics of carriers in excited semiconductors is presented. Fristly, a time-convolutionless equation of motion for the reduced density operator is derved from the microscopic Liouville wquation operator method. Secondly, the quantum kinetic equations for intercting electron-hole parirs near band-edge in semiconductors under an extermal optical field are obtained from the equation of motion for the reduced density operator. The non-Markovian optical gain of a driven semiconductor is derived including the many-body effects. plasma screening and excitinic effects are taken into account using as effective Hamiltonian in the time-dependent Hartree-Fock approximation. it is shown that the line shape of optical-gain spectra gain is enhanced by the exicitonic effects caused by the attrative electron-hole Coulomb interaction and the interference effects (renormalized memory effects) between the extermal driving filed and the intermal driving Filed and the stochastic reservoir of the system.