• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.228-231
• /
• 2017

The surface temperature of a combustor such as an aircraft engine is one of the important measuring factors related to the combustion performance. However, a conventional temperature measurement technique have a large measurement error due to a bad environment such as a combustion flame, vibration, and dust. In order to solve this problem, a technology has been developed which can measure the surface temperature of the combustor in real time using the wavelength change or attenuation time change according to the temperature of the phosphor. In this study, we developed a technique that can measure surface temperature of scram-jet combustor using phosphor thermometry. The calibration curve was obtained according to the temperature from $200^{\circ}C$ to $800^{\circ}C$ in the calibrated temperature chamber. So, we confirmed that phosphor thermometry can be used for measuring surface temperature of scram-jet combustor.

• Journal of Welding and Joining
• /
• v.26 no.5
• /
• pp.74-78
• /
• 2008

The laser welding of the car body and components has been spread in the automotive industry. The Nd:YAG laser welding system could be used in 3D welding with robot. However, this system cannot efficiently reduce the welding cycle time according to various welding sequences because the robot's moving time is same that of the resistant spot welding system. But the remote welding system with high power $CO_2$ laser and scanner makes it possible welding cycle time much faster than the robot laser welding system. In the $CO_2$ laser remote welding system, laser beam can be rapidly transferred to a workpiece by moving mirrors of scanner system. So, it makes reducing the cycle time of welding process and shaping various welding patterns easily. Therefore, in this paper, the characteristic of weld strength according to patterns of weld bead on $CO_2$ laser welding was investigated. Also, the relationship between shape of weld bead and value of tensile load was studied. Finally, the optimum remote welding condition for car bumper was investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.631-634
• /
• 2004

The method that exists in Photodynamic Therapy uses Photosensibility drug strongly Influencing tumour accumulation together with photochemical laser effect and makes the structure of tumour be localized and become extinct. The intracavity transformation of the Nd :YAP main radiation 1079 nm was Raman converted in barium nitrate crystal and the Stokes frequency (1216 nm) was doubled using KTP or RTA crystals. The LiF or Cr:YAG crystals are used for the Q-switch. The radiation Parameters were obtained at 100 Hz pump repetition frequency. The average power at 608 nm radiation with LiF and KTP was 700 mW at multi-mode generation. The 3-6 single 10-15 ns pulses were generated during one cycle of pumping. The doubling efficiency with RTA was two times more than with KTP. The cells of Ehrlich adenocarcinoma (0.1 ml) were i.m. implanted in hind thighs of ICR white non-imbred mice. The cells were preliminarily diluted in medium 199 in the ratio of 1 to 5. HpD was intravenous administered in a dose of 10 mg/kg. The left clean-shaven hind leg was irradiated with laser light 21-27 hours after the administration of the preparation. The right non-Irradiated leg of each animal served as a control. The animals with the transplanted tumor that were not injected with HpD sewed as a control to estimate the complex effect (HpD+ irradiation). Before the administration of HpD and on 3 and 4 days after irradiation the tumor size was measured and the percent of the tumor growth inhibition was calculated. The results of animal treatments has shown high efficiency of PDT method for cancer treatment by means 0.608 m high power pulse solid state laser.

• Medical Lasers
• /
• v.10 no.1
• /
• pp.31-36
• /
• 2021

Background and Objectives Several predicted optimal parameters for laser treatment have been suggested, making the settings subject to variation. Thus, picosecond lasers may require more data and studies to optimize the laser parameters, increase the efficacy of each session, and minimize the total number of sessions. This study evaluated the results of picosecond laser tattoo removal in variable locations, focusing on the aesthetic outcome, number of procedures, and adverse effects. Materials and Methods Nine patients who underwent picosecond laser treatment from February 2014 to July 2020 were enrolled. Before the procedures, the required number of sessions was estimated using the Kirby-Desai scale. At the end of the treatment, the patients assessed their satisfaction. The patient and two plastic surgeons assessed the clearance of the tattoo. Results The mean of the clearance was 86.6% in both the patient and investigators assessment. The patients reported satisfaction for an average score of 5.1 ± 0.78 for the aesthetic outcome, 4.5 ± 0.78 for pain, 4.1 ± 0.92 for the number of procedures, and 4.7 ± 0.97 for adverse effects. The average number of actual procedures was 6.7 ± 1.20. The average Kirby-Desai score was 7.1 ± 1.45. Their correlation coefficient was 0.803, which is considered a strong positive correlation. Conclusion Picosecond lasers have a remarkable ability to degrade smaller tattoo pigments through a photoacoustic effect. Moreover, a picosecond laser treatment for tattoo removal can be a safe and effective method. Picosecond lasers are a promising technology with the potential to optimize the treatment of tattoos.

• Medical Lasers
• /
• v.8 no.1
• /
• pp.1-6
• /
• 2019

Background and Objectives A facial laceration is a commonly occurring trauma of children. In addition, appropriate treatment and scar management are very important because the psychosocial impact of facial scars is much greater in children than in adults. Materials and Methods In the authors' hospital, primary closure was conducted targeting a total of 8,924 patients from January 2015 to December 2017. Of these, scar management was conducted on 808 people using a CO₂ fractional laser and Q-Switch Nd:YAG laser. To prove the effectiveness of the laser treatment on the linear scar, the patients were divided retrospectively into children and adults and sub-divided into those who received the treatment and those who did not. The subjective satisfaction of patients was evaluated using the Numeric Rating System (NRS). The objective scar scoring was evaluated using the image panel assessment based on the Vancouver Scar Scale (VSS), and the scoring was made by averaging the evaluations of three plastic surgeons. Results Evaluated NRS showed 8.50 ± 1.83 for adults without a laser, 8.51 ± 1.47 for adults with a laser, 7.93 ± 2.10 for children without a laser, and 8.9 ± 1.24 for children with a laser. The image panel assessment revealed 7.06 ± 1.31 for adults without a laser, 6.40 ± 2.37 for adults with a laser, 6.86 ± 1.45 for children without a laser, and 5.93 ± 1.21 for children with a laser. Conclusion When the linear scar is managed using a CO₂ Fractional laser, it can be managed in children better than adults, which is believed to be useful because it leads to better satisfaction and prognosis.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.4
• /
• pp.569-578
• /
• 2004

The purpose of this study was to clarify the palatal arch length, width and height in the primary and permanent dentition. Samples were consisted of normal occlusions both in the primary dentition(50 males and 50 females) and in the permanent dentition(50 males and 50 females). With their upper plaster casts were used and through 3-dimensional laser scanning(3D Scanner, DS4060, LDI, U.S.A.), cloud data, polygonization, section curve and loft surface, fit and horizontal plane were based to measure the palatal arch length, width and height(Surfacer 10.0, Imageware, U.S.A.). T-tests were applied for the statistical analyze of the data. The results were as follows : 1. In the measurement values, the values of the male were higher than those of the female except primary anterior palatal height. There were not only statistically significant differences in anterior palatal width(p<0.05) and posterior palatal width(p<0.01) in primary dentition but palatal width(p<0.05), anterior palatal length(p<0.01), middle and posterior palatal length(p<0.05) in permanent dentition between male and female. 2. In the indices of palate, there were statistically significant differences in height-length index(p<0.05) and width-length index(p<0.01) between male and female in primary dentition. In permanent dentition, there was statistically difference between male and female. 3. In the measurement values, posterior palatal width was increased most greatly. Posterior palatal height, anterior palatal width and anterior palatal length were followed by descending order. On the other hand, anterior palatal height and posterior palatal length were decreased. 4. In the indices of palate, the height-length index, the width-length index and posterior height-width index were increased, but the others were decreased.

• Korean Journal of Remote Sensing
• /
• v.35 no.6_3
• /
• pp.1187-1195
• /
• 2019

We, for the first time, developed a Raman lidar system which can remotely detect surface CO₂ volume mixing ratio (VMR). The Raman lidar system consists of the Nd: YAG laser of wavelength 355 nm with 80 mJ, an optical receiver, and detectors. Indoor CO₂ cell measurements show that the accuracy of the Raman lidar system is calculated to be 99.89%. We carried out the field measurement using our Raman lidar at Pukyong National University over a seven-day period in October 2019. The results show good agreement between CO₂ VMRs measured by the Raman lidar (CO₂ Raman Lidar) and those measured by in situ instruments (CO₂ In situ) which located 300 m and 350 m away from the Raman lidar system. The correlation coefficient (R), mean absolute error (MAE), and root mean square error (RMSE) between CO₂ In situ and CO₂ Raman Lidar are 0.67, 2.78 ppm, and 3.26 ppm, respectively.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.2
• /
• pp.198-205
• /
• 2003

Primary pulmonary lymphoma is rare, especially lymphomas arising in and limited to the tracheal wall without pulmonary parenchymal involvement are extremely rare. Bronchus-associated lymphoid tissue (BALT) lymphoma accounts for the majority of tracheal lymphomas. BALT lymphoma reveals distinct clinicopathologic features and remains localized for prolonged periods. The diagnosis is made histopathologically. Optimal management of these rare lesions has not been established. But, chemotherapy and radiation therapy all have been tried with favorable short-time results. The prognosis of BALT lymphoma is relatively good. We present here a case of BALT lymphoma of the tracheal wall which had responded to bronchoscopic ND-YAG laser therapy and local radiation therapy.