• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.87-95
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• 1995

In order to predict the case depth and case width in laser transformation hardening, a finite element method was used to analyze the temperature distribution on the material. Laser hardening of the specimens of SM45C and STE11steels was experimented by using the continuous wave CO$_{2}$ laser with the various travel speeds and the defocused Gaussian beam mode. Phosphate coating was adopted on the surface of SM45C to increase the absorption of 10.6 .mu. m laser energy. Experimental data show good agreement with the theoretical predictions. The maximum possible case depth can be predicted for the given laser hardening conditions, such as laser power, and travel speed.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.142-149
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• 1997

Ceramic-coated anilox roll for printing is resistant to corrosion and wear, and hence has enhanced life and quality. Laser engraving is used typically for machining holes to store ink in this roll. Since engraved hole size and shape are directly related to laser processing parameters, it is necessary to know the rela- tionships among these parameters. In this study, the parameters for engraving of ;oasma sprayed ceramic coatings with Nd:YAG laser were studied. Relationships between hole shape and processing parameters were analyzed. Cr$_{2}$O$_{3}$ceramic was found to be most suitable for Nd:YAG laser engraving. It was found that hole depth can be increased by using higher energy pulses. Effect of using different assistant gases was small to the final results. For better results, it was suggested to use a very stable laser with shorter pulses and higher pulse energy.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.10
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• pp.69-77
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• 1995

This laser measurement system has been developed using He-Ne laser and photodiode. The laser beam intensity transmitted on a photodiode was disturbed by eccentrically rotating disk cam with various speeds. The photodiode and an amplifier were used to change the detected beam intensity into voltage. The digitized data through the developed system were recorded on a micro-computer by using a signal analysis program. Its reliability was ascertained by using FFT analyzer. The vibration of rotating disk cam can be analyzed by measureing the intensity change of laser beam which the results by FFT analyzer were similar to. The amplifier was devised to be able to modulate the fluctuations of laser beam. The voltage could be linearly recorded with the change of the laser beam intensity.

• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.441-452
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• 2012

Objectives : As the attempts to make good uses of laser acupuncture in korean medicine have been steadily carried on, to ensure the safety is needed to increase the use of laser acupuncture. The aim of this study was to examine the safety of using laser acupuncture therapy irradiated with 830 nm laser and 905 nm laser. Methods : Fifteen rats were randomly divided into three experimental groups - Intact ; no therapy group. LAT830 ; laser acupuncture therapy(830 nm) group at GB34 GB39. LAT905 ; laser acupuncture therapy(905 nm) group at GB34 GB39. During eight weeks of treatment, LAT830, LAT905 were treated 2 times weekly, frequency 20 Hz, intensity 20 mW. Test items were mortality, body weight, food consumptions, hematological values, blood chemical values, urinalysis values, absolute organ weights and relative organ weights. Results : Statistically significant differences were not found among 3 groups. The values measured in LAT830, LAT905 and Intact(no therapy) group have shown similar results and it indicated that LAT830, LAT905 had no abnormal influence on the reaction of living bodies. There was little difference on the liver weight of relative organ weight test between laser-treated groups(LAT830, LAT905) and Intact group. Conclusions : In conclusion, laser acupuncture therapies irradiated with 830 nm laser and 905 nm laser caused no abnormal reaction of living bodies. More studies are needed to further establish the safety of many other laser acupuncture therapies.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.1005-1013
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• 2001

The present study was designed to investigate the effect of low power GaAlAs laser on spinal Fos expression related to the anti-nociceptive effect of laser stimulation. Low power GaAlAs laser was applied to either acupoint or non-acupoint for 2 hour under light inhalation anesthesia. Spinal Fos expression in the dorsal horn was compared to that obtained in inhalation anesthesia control group. Furthermore, we analyzed the effect of the local treatment of lidocaine on the spinal Fos expression evoked by low power GaAlAs laser stimulation. The results were summarized as follows: 1. In the normal animals, only a few Fos like immunoreactive(Fos-IR) neurons were evident in the lumbar spinal cord dorsal horn. Similarly, following prolonged inhalation anesthesia, Fos-IR neurons were absent in the dorsal horn of the lumbar spinal cord. In animals treated with laser stimulation, Fos immunoreactive neurons were increased mainly in the medial half of ipsilateral laminae I-III at lumbar segments L3-5. These findings directly indicated that prolonged anesthesia used in this study did not affect the Fos expression in the spinal cord dorsal horn of intact animals and low power laser stimulation dramatically produced Fos expression in the spinal cord laminae that are related to the anti-nociceptive effect of laser stimulation. 2. In acupoint stimulated animals, 10mW of laser stimulation, not 3mW and 6mW intensity, significantly increased the number of Fos immunoreactive neurons in the spinal dorsal horn(p<0.05). However, laser stimulation on acupoint more dramatically increased the number of Fos immunoreactive neurons in the spinal cord rather than laser stimulatin on non acupoint. These result suggested that laser stimulatin on acupoint was more effective treatment to activate the spinal neuron than non acupoint stimulation. 3. The local treatment of lidocaine totally suppressed the activity of spinal neurons that were induced by lower power 1aser stimulation. These data indicated that the anti-nociceptive effect of laser stimulation was absolutely dependent upon the peripheral nerve activity in the stimulated location. In conclusion, these data indicate that 10mW of low power laser stimulation into acupoint is capable of inducing the spinal Fos expression in the dorsal horn related to the anti-nociceptive effect of laser stimulation, Furthermore, the induction of spinal Fos expression was totally related to the peripheral nerve activity in the laser stimulated area.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.303-304
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• 2008

• Proceedings of the Korean Society of Laser Processing Conference
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• 2003.05a
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• pp.35-38
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• 2003

• Proceedings of the Korean Society of Laser Processing Conference
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• 2003.05a
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• pp.92-95
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• 2003

• Proceedings of the Korean Society of Laser Processing Conference
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• 2005.06a
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• pp.91-96
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• 2005

• 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