• 대한전기학회논문지
• /
• 제45권2호
• /
• pp.289-293
• /
• 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
• /
• 제13권5호
• /
• pp.553-556
• /
• 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
• /
• 제10권1호
• /
• pp.52-54
• /
• 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.

• 대한후두음성언어의학회지
• /
• 제21권2호
• /
• pp.112-120
• /
• 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.

• 한국임상수의학회지
• /
• 제26권6호
• /
• pp.563-567
• /
• 2009

Steel scalpel과 $CO_2$ laser를 이용한 돼지 자궁 절개 시 창상 치유에 미치는 영향을 평가하고자 본 실험을 실시하였다. 다섯 마리의 Landrace - Yorkshire 혼혈 종 돼지를 이용하였고, 각각의 돼지에서 좌측 및 우측의 자궁에 대칭적으로 scalpel과 $CO_2$ laser를 이용하여 절개 하였다. 각각의 기구는 절개 속도, 절개의 용이성 및 출혈 정도를 평가 하였으며 수술 후 21일에 육안적인 유착 정도와 조직학적 검사를 실시하였다. Scalpel을 이용한 절개는 레이저를 이용한 절개보다 용이하였으나 두 군간의 유의성은 없었다. 레이저를 이용한 절개 시 출혈량은 적었으나 절개속도는 scalpel을 이용한 경우가 빨랐다. $CO_2$ laser 절개에서의 수술 후 자궁 유착은 scalpel 절개에서 보다 적게 발생하였다. 조직학적 검사에서 scalpel 절개의 경우 상피 조직과 자궁내막선의 재생이 완전히 이루어 졌으나 레이저를 이용한 경우 불완전한 재생 상태를 보였다. 비록 scalpel을 이용한 절개가 $CO_2$ laser를 이용한 경우 보다 조직 손상이 적었으며 사용하기 용이하였으나 출혈이 많은 단점이 있다. 반면 $CO_2$ laser를 이용한 절개의 경우 지혈 효과는 좋으나 창상 치유를 지연 시켰다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1989년도 하계종합학술대회 논문집
• /
• pp.439-442
• /
• 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.

• 대한기계학회논문집B
• /
• 제23권11호
• /
• pp.1379-1389
• /
• 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.

• 대한수의학회지
• /
• 제50권3호
• /
• pp.247-251
• /
• 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.

• 한국광학회:학술대회논문집
• /
• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.39-42
• /
• 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.

• 대한의생명과학회지
• /
• 제15권1호
• /
• pp.81-86
• /
• 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.