• The Journal of Korean Physical Therapy
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• v.14 no.2
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• pp.16-25
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• 2002

Low energy laser irradiation(LELI) therapy in physical therapy is widespread but the mechanisms are not fully understood. The purpose of the present study was to examine the epidermal growth factor(EGF)'s expression within lumbar spinal cord which corresponding with crushed extensor digitorum longus(EDL) of rats after low-power laser irradiation applied. After a crushed injury on the right EDL, low-power laser irradiation was applied by using 2000mW, 2000Hz, 830nm GaAlAs(Gallium-aluminum-arsenide) semiconductor diode laser. The laser treatment was performed with 10 minutes daily for 3days. After EDL crush injury, EGF immunoreactive positive neurons in experimental group were progressively decreased from the first to third days. Especially 1 day subgroup is highly expressed in dorsal horn(Lamina I, II, III) and around of central cannal of spinal cord(Lamina VII). Control group was only expressed slightly at 3 days. This study suggests that LELI stimulate that release and migration of EGF in spinal cord, which distict to wound site, therfore promote wound healing of EDL crush injury.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.605-610
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• 2021

Wireless charging method using a laser is considered as the most efficient method at a long distance of the wireless charging method. Combining long-range laser wireless charging technology with wireless communication technology will make it possible to use it for a variety of applications. Accordingly, this paper shows the results of research and experiments on wireless charging and wireless communication simultaneously based on a laser. This technique uses a laser as a light source for E/O(: Electric-to-Optical) conversion at the transmitter for optical wireless power transmission. In the experimental results, the optical power transmission using a 100 mW laser transmitter and a solar cells receiver showed a DC-to-DC efficiency of 1.9 %, wireless optical communication showed a transmission speed of up to 90 kbps when the transmission distance is 15 m.

• Biomedical Science Letters
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• v.14 no.2
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• pp.83-89
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• 2008

We have compared the antitumor effect of photodynamic therapy (PDT), using 5-aminolevulinic acid (ALA) as the photosensitizer, combined with cisplatin (CDDP) on AMC-HN3 human squamous cell carcinoma. AMC-HN3 cells were cultured and then incubated with various concentrations of CDDP and ALA. 632 nm diode laser was given at $6.0J/cm^2$ followed by incubation for 24 hours. The evaluation of cell viability was done by MTT assay. In vivo CDDP was injected intraperitoneally 24 hours prior to PDT. The anti-tumor effects of each treatment were measured by tumor volume change. Cell viability were 44.29% for the cisplatin-mediated chemotherapy group $(6.25{\mu}g/ml)$, 77.22% for ALA-PDT group, and 15.06% for the Combination therapy group. In vivo, the antitumor effect of photodynamic therapy was enhanced by combination of Cisplatin-mediated chemotherapy. Photodynamic therapy combined with administration of Cisplatin appears to enhance antitumor effect and to be a useful treatment modality.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.93-99
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• 1998

Although laser interferometer measurement system has advantages of measurement range and accuracy, it has some disadvantages when measurement of multi degrees of freedom of motion are required. Because the traditional error measurement methods for geometric errors (two straightness and three angular errors) of a slide of machine tools measures error components one at a time. It may also create an optical path difference and affect the measurement accuracy. In order to identify and compensate for geometric errors of a moving rigid body in real time processes, an on-line error measurement system for simultaneous detection of the five error components of a moving object is required. Using laser alignment technique and some optoelectronic components, an on-line measurement system with 5 degrees of freedom was developed for the geometric error detection in this study Performance verification of the system has been performed on an error generating mechanism. Experimental results show the feasibility of this system for identifying geometric errors of a slide of machine tools.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.388-393
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• 1992

An infrared range finder using a self-mixing laser diode (SM-LD), which has been proposed and developed by the Authors, can measure not only a range of a moving target but its velocity simultaneously. In this paper, described is that the precise mode-hop pulse train can be obtained by employing a new signal processing circuit even when the backscattered light returning into the SM-LD is much more weaker. As a result, the distance to a tilted square sheet made from aluminium or white paper, which is placed 10 cm through 60 cm from the SM-LD, is measured with accuracy of a few percent even when the tilting angle is less than 75 degrees or 85 degrees, respectively. And in this paper, described is the range-image recognition of a plane object under the condition of standstill. The output laser beam is scanned by scanning two plane mirrors-equipped with each stepping motor. And we succeeded in the acquisition of the range-image of a plane object in a few tens of seconds. Furthermore, described is a feasibility study about the range-image recognition of a slowly moving plane object.

• Current Optics and Photonics
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• v.3 no.6
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• pp.577-582
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• 2019

We report on a continuous-wave (cw) optical parametric oscillator (OPO) optimized for mid-infrared emission above 5.0 ㎛. The OPO is based on a magnesium-oxide-doped periodically poled LiNbO₃(MgO:PPLN) crystal with a fan-out grating design. A linear two-mirror cavity resonating both at the pump and signal wavelengths is stabilized to the pump laser by using the modified Pound-Drever-Hall (PDH) method. The idler wavelength is continuously tunable from 4.7 ㎛ up to 5.3 ㎛ by varying the poling period of the fan-out grating crystal. Pumped by a diode-pumped solid state (DPSS) laser with a power of 1.1 W at 1064 nm, the maximum idler output power is measured to be 5.3 mW at 4.8 ㎛. The output power above 5.0 ㎛ is reduced to the hundreds of ㎼ level due to increased absorption in the crystal, but is stable and strong enough to be measured with a conventional detector.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.96-101
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• 2004

In order to measure the retina thickness, there are to need the 3-D retina photographing and the high speed signal processing system. In this paper, we introduced the retina photographing system and the 16-channel high speed image data acquisition system. There are able to measure the retina thickness with sensing image the returned laser signal to APD sensor after there were projected the HeNe laser on retina. We developed the laser projection system to sense a reflected image of the retina using APD sensor, the 16-channel high speed A/D converter and PCI master interface card for image transmission into computer.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.44-48
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• 2002

In this paper, we demonstrated the simultaneous measurment of triple parameters such as strain, temperature, and vibration using single FBG/EFPI hybrid sensor. The FBG/EFPI sensor system for the strain and temperature measurement and the EFPI sensor system for the the vibration measurement were combined by a wavelength division multiplexer. The optical source of FBG/ EFPI sensor system is a wavelength-swept fiber laser(WSFL) and that of an EFPI sensor system is a laser diode. We performed the simultaneous measurement of thermal strain, temperature, and vibration of a aluminum beam placed in a thermal chamber and validated the efficiency of the constructed measurment system.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2005.11a
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• pp.50-56
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• 2005

The robot systems are widely used in the many industrial field as well as welding manufacturing. The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot tracking, many kinds of contact and non-contact sensors are used. Recently, the vision is most popular. In this paper, the development of the system which measures the shape of the welding part is described. This system uses the line-type structured laser diode and the vision sensor. It includes the correction of radial distortion which is often found in the image taken by the camera with short focal length. The Direct Linear Transformation (DLT) method is used for the camera calibration. The three dimensional shape of the parent metal is obtained after simple linear transformation. Some demos are shown to describe the performance of the developed system.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.558-563
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• 1995

Dynamic characteristics of TbFeCo magneto-optical recording media at 680nm wavelength region were studied by means of computer simulation of disc structure and optimization of process variables during sputter deposition. With the slightly reduced Kerr rotation angle due to the reduced wavelength of optical laser source, the improved recording density in TbFeCo magneto optical media showing the CNR greater than 50dB could be achieved by only adjusting the thickness of dielectric and the recording layers when the wavelength of light source is changed from 780nm to 680nm. In addition, the recording power margin of 5mW and the 2mW minimum recording power was realized, It was shown from the present study that the increase in laser power density demonstrated feasibility of low cost and low power laser diode with the reduced optimum recording power.