• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.289-293
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• 1996

The basic study on laser triggered lightning was carried out for the active protection of lightning in power transmission system. The lengths of generated plasma channels were simulated numerically for variations of energy and pulse width of CO$_{2}$ laser by Runge-Kutta-Gill method. As results, the effective lengths of plasma channels were 2.3m, 2.67m and 3.4m respectively for energy of 45J, 60J and 100J of CO$_{2}$ laser pulse with pulse width of 50nsec using focusing mirror with focal length of 10m. And also the effects of pulse width of first pulse and tail pulse of CO$_{2}$ laser on the length of plasma channel were examined.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.553-556
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• 1992

The ${CO}_2$ laser absorption measurement of ${CH}_3{CH}_2Br$ utilizing photoacoustic (PA) technique was performed using a cw and a pulsed ${CO}_2$ lasers. The absorption profile in the ${CO}_2$ laser wavelength region (9-10 ${\mu}$m) and the macroscopic small signal absorption cross section at 10P(20) (10.59 ${\mu}$m, 944 $cm^{-1}$) laser line were measured using a cw ${CO}_2$ laser. The laser fluence dependence on infrared multiphoton absorption (IRMPA) was also studied with a pulsed TEA ${CO}_2$ laser at 10P(20) laser line. In view of monotonic increase of PA signal with the rise of laser fluence, it was suggested that the anharmonicity in pumped vibration mode did not restrict ir multiphoton absorption in ${CH}_3{CH}_2Br$ system as found in large molecular system.

• Medical Lasers
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• v.10 no.1
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• pp.52-54
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• 2021

There is growing interest in minimizing postoperative scarring after a thyroidectomy. Among the many treatment types, laser therapy, especially picosecond-domain laser therapy, is accepted as a standard method. In the present case, a patient with a pigmented, contracted scar was treated using the combination of a picosecond laser and ablative fractional (AF) CO₂ laser. After 15 sessions of 1,064-nm picosecond with micro lens array (MLA) and AF CO₂ laser application, the patient showed significant improvement in their pigmented lesions and scar contracture with no noticeable side effects for 16 months. These results suggest that a combination of picosecond laser with MLA and AF CO₂ laser can treat pigmented, contracted scars safely and effectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.2
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• pp.112-120
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• 2010

Transoral $CO_2$ laser microsurgery has been widely used for various laryngeal diseases. Laser cordectomy for the management of early laryngeal carcinoma has advantages with regards to oncologic results, preservation of laryngeal functions, morbidity and cost in comparison to those of open surgery or radiation therapy. $CO_2$ laser is also applicable to benign vocal fold lesions such as nodules, polyps, cysts, reinke's edema, granulomas, papillomas, hemangiomas and glottis webs. $CO_2$ laser is suitable for microsurgery because it has small focus size and hemostatic effect. We should also recognize the risks of $CO_2$ laser for safe use.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.563-567
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• 2009

This study compared the instrument performance and tissue healing of a steel scalpel with a $CO_2$ laser in an animal uterine surgery model. Five Landrace and Yorkshire mixed breed pigs were used. Two symmetrical incisions were made in the uterine of each pig. One incision was made on the left side of the uterine horn using a steel scalpel, while the other incision was performed on the right side using a $CO_2$ laser with an 8W output power. Each instrument was evaluated clinically for speed, ease of incision, and extent of bleeding. An ovariohysterectomy was performed at 21 days after the surgical procedure for a histological examination. The scalpel was an easier instrument to use in the confines of the uterine tissue, compared with the laser. However, there is no significant difference between the two groups. The amount of bleeding was less in the laser group but the time of the incisions was shorter with the scalpel. Postoperative uterus adhesion in the $CO_2$ laser incisions was lower than the scalpel incisions. Scalpel incisions showed complete restoration of the epithelium and endometrial gland. On the other hand, the laser incisions showed incomplete restoration of the epithelium and endometrial gland. Although the scalpel produced less damage to the uterine tissue and was easier to handle than the $CO_2$ laser, it did not provide hemostasis that was helpful for use on highly vascular tissue. The $CO_2$ laser provided good hemostasis but delayed wound healing.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.439-442
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• 1989

$CO_2$ lasers are used in the various industrial fields since the development of $CO_2$ laser in 1964 It is because $CO_2$ laser is more efficient, more powerful than other lasers and $CO_2$ laser light of wavelength $10.6{\mu}m$ interacts with materials well. Thus $CO_2$ laser is used for industrial application such as cutting, punching, welding, surface treatment of metal and nonmetalic materials, isotope separation, etc. Already other research institutes including some universities have recognized the advantages and importance of the $CO_2$ laser, and studied it. However, its technology is in elementary state yet Therefore,we started this study to develop present $CO_2$ laser technology more highly and to fit it. The main purposes of this study are to acquire various technologies such as high voltage, high pressure glow discharge, vaccum and optical cavity design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1379-1389
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• 1999

A new technique for control of size and shape of flame-made particles is Introduced. The characteristic sintering time can be controlled Independently of collision time by heating the particles with irradiation of laser because the sintering time strongly depends on temperature. A coflow oxy-hydrogen diffusion flame burner was used for $SiCl_4$ conversion to silica particle. Nanometer sized aggregates irradiated by a high power CW $CO_2$ laser beam were rapidly heated up to high temperatures and then were sintered to approach volume-equivalent spheres. The sphere collides much slower than the aggregate, which results in reduction of sizes of particles maintaining spherical shape. Light scattering of Ar ion laser and TEM observation using a local sampling device were used to confirm the above effects. When the $CO_2$ laser was irradiated at low position from the burner surface, particle generation due to gas absorption of laser beam occurred and thus scattering intensity increased with $CO_2$ laser power. At high irradiation position, scattering intensity decreased with $CO_2$ laser power and TEM image showed a clear mark of evaporation and recondensation of particles for high $CO_2$ laser power. When the laser was irradiated between the above two positions where small aggregates exist, average size of spherical particles obviously decreased to 58% of those without $CO_2$ laser irradiation with the spherical shape. Even for increased carrier gas flow rate by a factor of three, TEM photograph also revealed considerable reduction of particle size.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.247-251
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• 2010

This study compared the instrument performance and tissue healing of a steel scalpel with a $CO_2$ laser in an animal urinary bladder surgery model. Landrace and Yorkshire mixed breed pigs were used. Two symmetrical incisions were made in urinary bladder of each pig. One incision was made on the left side of ventral aspect on urinary bladder using a steel scalpel, while the other incision was performed on the right side using a $CO_2$ laser with an 8W output power. Each instrument was evaluated clinically for speed, ease of incision, and extent of bleeding. At 7 and 21 days after initial wounding, each wound was taken for histological observations. The scalpel was an easier instrument to use in the confines of the urinary bladder tissue, compared with the laser. However, there was no significant difference between the two groups. The amount of bleeding was less in the laser group but the time of the incisions was shorter with the scalpel. Scalpel incisions showed complete restoration of the epithelium and muscularis. On the other hand, the laser incisions showed incomplete restoration of the epithelium and muscularis. However, most of wound healing in the laser incisions was accomplished according to the time lapse. Although the scalpel produced less damage to the urinary bladder tissue and was easier to handle than the $CO_2$ laser, it did not provide hemostasis that was helpful for use on highly vascular tissue. The $CO_2$ laser provided good hemostasis, but delayed wound healing. In conclusion, the $CO_2$ laser provided better hemostasis and better surgical field than the scalpel. The $CO_2$ laser was used effectively in urinary bladder incision.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.39-42
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• 1989

The limitations of high-power electrical lasers due to heating of the gas and the instability of the glow discharge can be alleviated by the flow of the lasing medium. In order to achieve high power and efficient laser, we are developing a fast-axial flow CO2 laser. We describe here the classification of gas-discharge CO2 lasers according to the cooling methods of the lasing medium and the design features of the fast-axial flow CO2 laser.

• Biomedical Science Letters
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• v.15 no.1
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• pp.81-86
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• 2009

Lasers are necessity in our life related to the fields of medicine and cosmetic surgery. With 808 nm diode laser and $CO_2$ laser, we made some wounds on a dorsum of rat by laser irradiation. All of irradiations shows thermal effects on the whole region of skin tissues. They make wound damage depending on laser power and irradiation time. Because a collagen is plays an important role in tissue repair, we studied collagen accumulation in wound tissue. For wound healing, collagen accumulation was found in the near region of damage in epidermis and dermis layer of the rat skin. In case of the quantitative analysis of collagen in wound tissue, the amount of collagen in wound tissue by $CO_2$ laser irradiation is higher than that of 808 nm diode laser irradiation. And re-epithelialization was significantly faster in wound by $CO_2$ laser irradiation compared with that of 808 nm diode laser irradiation.