• Bulletin of the Korean Chemical Society
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• v.21 no.4
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• pp.389-392
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• 2000

A simple and inexpensive colorimetric spectrometer for determining total cholesterol has been developed,comprising a diode laser as the light sourcoptical fibers for the light guide and a photodiode as the detector.The stabilty and performance of the new system was investigated by obtaining the calibration curve for stan-dard cholesterol solutions. The total cholesterol in humanserum was also measured by the analyzer and com-pared with the value obtained by a conventional spectrometer. The results showed that the developed spectrometer was useful for the determination of cholesterol levels. The visible diodelaser used in the study exhibited good spectroscopic and operational properties for colorimetric absorption spectrometry and could be a key component for the development of a simple and economical analyzer.

• Korean Journal of Optics and Photonics
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• v.23 no.3
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• pp.124-127
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• 2012

We designed and fabricated dichroic filters for high-power fiber lasers to protect the pumping laser diode from counterpropagating laser beams. The transmittance at laser diode wavelengths of 905 nm~925 nm was designed to be less than 0.1% and the transmittance at the fiber laser or Brillouin scattering wavelengths of 1020 nm ~ 1100 nm was designed to be more than 99.9%. Since oxide materials have good adhesion to the $SiO_2$ substrate, $SiO_2/Ta_2O_5$ were used as coating materials. The filter was fabricated according to our optimized design and its characteristics were compared with the theoretical design. As a result, the transmittance at laser diode wavelengths of 905 nm~925 nm was measured to be less than 0.1%, and the transmittance at the fiber laser or Brillouin scattering wavelengths of 1020 nm~1100 nm was measured to be more than 95.5%, which coincided well with the theoretical design considering processing errors. The filter was found to operate well over 1W of input laser power.

• The Journal of Pediatrics of Korean Medicine
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• v.29 no.4
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• pp.29-38
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• 2015

Objectives We aimed to identify the effectiveness of photobiomodulation using low level laser therapy (LLLT), light emitting diode (LED) and others on the growth of the length of the growth plate by reviewing literatures. Methods We searched literatures using PubMed, Science Direct, CINAHL, Korea Traditional Knowledge Portal (KTKP), Oriental Medicine Advanced Searching Integrated System (OASIS), China Knowledge Resource Integrated Database (CNKI), Japan Science and Technology Information Aggregator, Electronic (J STAGE), and Japan National Institute of Informatics Scholarly and Academic Information Navigator (CiNii) using the keywords "Growth plate" "Epiphyseal growth" "Epiphyseal plate" and "Laser", "light emitting diode (LED)", "near-infrared light", and "photobiomodulation". Search range included only original article which provided English abstract were selected. The search strategy contained no language limitation. Results A total 556 studies were found. Then, 551 were excluded by scanning titles and abstracts and finally 5 articles were selected. Five articles were RCTs using rodents. Two of the 5 articles used InGaAlP Laser (630-685 nm), and the other 3 articles used GaAlAs Laser (780, 820, and 870 nm) to investigated the effects of LLLT on the growth of the length of the epiphyseal cartilage and the number of chondrocytes and thickness of each zone of the epiphyseal cartilage. Two articles concluded that LLLT had a beneficial effect on the longitudinal growth of the growth plate. In growth of the epiphyseal plate, there were no significant differences in others. Conclusions It is might that LLLT influenced on the growth of epiphyseal plate by positive affect. However, further rigorous RCTs are warranted.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.5
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• pp.88-98
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• 1999

A refractive index modulated (RIM) DFB laser, in which the refractive index of a center region of the upper cladding layer comprising the grating region is different from that of side regions, is proposed to obtain and effective ${\lambda}$/4 phase shift in the center region. Since the coupling coefficient of a center region in a RIM-DFB laser is larger than that of side regions, a RIM-DFB laser has the effect of a distributed coupling coefficient. Simulation results show that RIM-DFB lasers have better operation characteristics - more uniform photon density profile, less SHB effect, and better single mode operation at high injection currents - compared to those of ${\lambda}$/4 phase-shifted DFB lasers and CPM-DFB lasers. In addition, the effect of the center region on the above threshold characteristics of a RIM-DFB laser is investigated.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.120-124
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• 2009

The concept of biostimulation of wounds by low-level laser therapy(LLLT) is attracting considerable attention. Although its effect on whole tissues has been studied quite extensively, the biological and cellular mechanisms underlying LLLT have not been clarified. In an experimental radius fracture in rabbits, Tang and Chai reported that LLLT enhanced the activity of red blood cells, macrophages, fibroblasts, chondrocytes, and osteoclasts within the fracture area. The purpose of the present study was to evaluate the effect of LLLT with a GaAlAs diode laser device on bone healing in rabbit mandibular fractures. We use 12 rabbits for this study. All rabbits were fractured mandible angle area using saw in anesthetic condition. In control group(n=6), none treatment was performed at fracture site. In experimental group(n=6), LLLT with a GaAlAs diode laser was radiated at fracture site daily for 7 days. All rabbits were sacrificed at 6 weeks later from performed fracture day. We studied the immunohistochemical staining of CD34 and Vimentin and the histochemical analysis for calcium and phosphorus content. The results were as follows. 1. In the histological and immunohistological staining, after 6week, fibroblasts, osteogenic cells and collgen fibers were observed more in experimental group than in control group. 2. In the histochemical analysis, the amount of calcium and phosphorus contents of the experimental group were more than the control group. From the results obtained, we suggest that the bone healing is stimulated by low-level laser irradiation in bone fractures.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.11
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• pp.707-711
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• 2016

ITO/Ag/ITO conductive films on PET (polyethylene terephthalate) was etched by a Q-switched diode-pumped neodymiun-doped yttrium vanadate (Nd:YVO4, ${\lambda}=1064nm$) laser. During the laser direct etching, the laser beam was incident on the two different directions of PET and the etching patterns were investigated and analyzed. At a lower repetition rate of laser pulse, the larger laser etched patterns were obtained by laser beam incident on reverse side of PET substrate. On the contrary, at a higher repetition rate, it was possible to find the larger etched patterns in case of the laser beam incidence on forward side of PET substrate. For the laser beam incidence on reverse side, the laser beam is expected to be transferred and scattered through the PET substrate and the laser beam energy is thought to be dependent on the etch laser pulse beam energy.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.943-946
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• 2004

We report the laser scanning display as an emerging technology. We show demonstration system of laser TV, Video image is made by using a high speed MEMS scanning mirror and a direct-modulated red diode laser. We designed and fabricated MEMS scanning mirror. The first demonstration system showed a NTSC-resolution video image with the image size of 5 inches. The successful development of compact laser TV will open a new area of home application of the laser light.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.606-611
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• 2002

Welding using lasers can be mass-produced in high speed. In the laser welding, performing real-time monitoring system of the welding quality is very important in enhancing the efficiency of welding. In this study, the plasma and molten metal which are generated during laser welding were measured using the UV sensor and IR sensors. The results of laser welding were classified into five categories such as optimal heat input, little low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. Also, a system was formulated which uses the measured signals with a fuzzy pattern recognition method which is used to perform real-time evaluation of the welding quality and the defects which can occur in laser welding.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.293-324
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• 1996

Compact solid-state blue laser have great potential for use in optical data storage, laser beam printing, particle countering, reprographics, holography, and fluorescent bioanalysis. We report recent progresses in qualities of LiB3O5 and K3Li2(TaxNb1-x)5O15 nonlinear crystals which are essential in manufacturing bulk-type blue SHG devices. We also review newly developed violet-blue laser, 20 mW output, using intracavity frequency doubling of a diode laser pumped Cr:LiSrAlF6 laser with low loss LiB3O5 crystal as a frequency doubler.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.204-210
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• 1986

In this paper, a new method is suggested to stabilize the frequency of semiconductor laser diode for heterodyne optical communication systems. In order to stabilize the frequency of semiconductor laser, the method of the injection current controal has been widely used, in which the laser frequency is locked to a F-P interferometer. By adding another servoloop to stabilize the output power of semiconductor laser, we could stabilize the laser frequency and the output power simultaneously and the frequency stability is improved by a factor of fice times.