• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.440-441
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• 2007

For this study, terbium-doped yttrium aluminum garnet (YAG:Tb) phosphor powders were prepared via the combustion process using the varous reagents. The characteristics of the synthesized nano powder were investigated by means of X-ray diffraction (XRD), Scanning Electron Microscope(SEM), and photoluminescence (PL). Single-phase cubic YAG:Tb crystalline powder was obtained at $1000^{\circ}C$ by directly crystallizing it from amorphous materials, as determined by XRD techniques. The SEM image showed that the resulting YAG:Tb powders had uniform sizes and good homogeneity. The photoluminescence spectra of the YAG:Tb nanoparticles were investigated to determinethe energy level of electron transition related to luminescence processes. There were three peaks in the excited spectrum, and the major one was a broad band of around 274 nm. Also, the YAG:Tb nanoparticles showed two emission peaks in the range of 450~500 nm and 525~560 nm, respectively, and had maximum intensity at 545 nm.

• Medical Lasers
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• 제8권2호
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• pp.74-79
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• 2019

Periorbital melasma is often refractory to treatment and highly associated with rebound hyperpigmentation or mottled hypopigmentation after laser treatment in Asian patients. In this report, we describe 2 patients with cluster-1 periorbital melasma and 1 patient with cluster-2 periorbital melasma who experienced remarkable clinical improvements after microwave-generated, atmospheric-pressure, non-thermal nitrogen plasma treatments. All patients exhibited limited clinical responses after combination treatments with topical bleaching agents, systemic oral tranexamic acid, and low-fluenced Q-switched neodymium (Nd):yttrium-aluminum-garnet (YAG) lasers. Low-energy nitrogen plasma treatment at 0.75 J elicited remarkable clinical improvement in the periorbital melasma lesions without post-laser therapy rebound hyperpigmentation and mottled hypopigmentation. We deemed that a single pass of nitrogen plasma treatment at 0.75 J induces mild microscopic thermal tissue coagulation and modification within the epidermis while preserving the integrity of the basement membrane in patients with periorbital melasma. Accordingly, nitrogen plasma-induced dermal tissue regeneration could play a role in the treatment of melasma lesions.

• The Journal of Advanced Prosthodontics
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• 제14권5호
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• pp.305-314
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• 2022

PURPOSE. The aim of this study was to evaluate the flexural strength of a 3D-printed denture base resin (Cosmos Denture), after different immediate repair techniques with surface treatments and thermocycling. MATERIALS AND METHODS. Rectangular 3D-printed denture base resin (Cosmos Denture) specimens (N = 130) were thermocycled (5,000 cycles, 5℃ and 55℃) before and after the different repair techniques (n = 10 per group) using an autopolymerized acrylic resin (Jet, J) or a hard relining resin (Soft Confort, SC), and different surface treatments: Jet resin monomer for 180 s (MMA), blasting with aluminum oxide (JAT) or erbium: yttrium-aluminum-garnet laser (L). The control group were intact specimens. A three-point flexural strength test was performed, and data (MPa) were analyzed by ANOVA and Games-Howell post hoc test (α = 0.05). Each failure was observed and classified through stereomicroscope images and the surface treatments were viewed by scanning electron microscope (SEM). RESULTS. Control group showed the highest mean of flexural strength, statistically different from the other groups (P < .001), followed by MMA+J group. The groups with L treatment were statistically similar to the MMA groups (P > .05). The JAT+J group was better than the SC and JAT+SC groups (P < .05), but similar to the other groups (P > .05). Adhesive failures were most observed in JAT groups, especially when repaired with SC. The SEM images showed surface changes for all treatments, except JAT alone. CONCLUSION. Denture bases fabricated with 3D-printed resin should be preferably repaired with MMA+J. SC and JAT+SC showed the worst results. Blasting impaired the adhesion of the SC resin.

• 한국결정성장학회지
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• 제7권1호
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• pp.18-26
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• 1997

소결조제로 Y 3Alo012를 첨가한 {3- SiC 분말에 seed로서 1 wt%의 a- SiC 분말을 첨 가한 시편과 첨가하지 않은 시편을 1950$^{\circ}$C, argon 분위기에서 0.5~4시간 동안 소결하였다. S Seed로써 1 wt% a-SiC 분말의 첨가는 소결 도중에 길게 자란 업자틀의 성장을 가속시켰고, a a- SiC seed를 첨가한 시편에서 더 조대한 미세구조가 얻어졌다 .. a-SiC seed를 첨가하여 4시간 동안 소결한 시편의 파괴인성은 7.5 MPa'ml/2이었고, seed를 첨가하지 않은 시편의 파괴인성은 6 6.1 MPa'm1/2이었다 .. Seed를 첨가한 시편의 높은 파괴인성은 조대한 미세구조에 포함된 길게 자란 입자들에 의한 균열가교 기구의 활발한 작용에 기인한다.

• Archives of Reconstructive Microsurgery
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• 제2권1호
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• pp.82-92
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• 1993

A comparative study was undertaken to evaluate the contact Neo-dymium : yttrium aluminum garnet(Nd:YAG) laser system for vascular anastomosis of small caliber blood vessels(diameter 0.5-1.2 mm) in the animal model. In this study 40 femoral arteries and 40 femoral veins of Sprague-Dawley rats were anastomosed by contact laser assisted microvascular anastomosis(LAMA) utilizing 3 stay sutures which were placed 120 degrees apart and the intervals welded with contact Nd:YAG laser unit, conventionally sutured anastomosis(CSA) served as controls. The time needed for vascular anastomosis, patency rate(immediate postoperative, postoperative 2nd day, postoperative 1 week, postoperative 4 weeks), gross and microscopic evaluations were compared to conventional microsurgical suture technique. The results are as follows: 1. Postoperative patency rate was 82.5% for femoral artery and 75% for femoral vein by contact LAMA technique compared to 90% and 75% by CSA technique at postoperative 4 weeks. 2. Less time-consumed for arterial anastomosis by 6 minutes 23 seconds and venous anastomosis by 8 minutes 55 seconds with contact LAMA technique compared to CSA technique. 3. Grossly almost complete healing had taken place by postoperative 1 week by contact LAMA technique. 4. Aneurysm formation was 5% for femoral artery and 15% for femoral vein by contact LAMA technique compared to 5% and 10% respectively by CSA technique. 5. Microscopically, re-endothelization was complete by postoperative 7th day by contact LAMA technique. There was less medial hypertrophy and hyperplasia and also less inflammatory response compared to CSA.

• Archives of Plastic Surgery
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• 제39권2호
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• pp.143-149
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• 2012

Background : Axillary osmidrosis is characterized by an unpleasant odor, profuse sweating, and in some instances, staining of clothes that may socially and psychologically impair affected individuals. Various types of surgical procedures have been developed for the treatment of axillary osmidrosis. This study was undertaken to evaluate the effectiveness of subcutaneous pulsed neodymium: yttrium-aluminum-garnet (Nd-YAG) laser treatment for the treatment of axillary osmidrosis. Methods : Twenty-nine patients with axillary osmidrosis were included in this study. Patients were categorized according to the results of an axillary malodor grading system, and a subcutaneous pulsed Nd-YAG laser was applied to all patients. The treatment area for the appropriate distribution of laser energy was determined using the iodine starch test (Minor's test) against a grid pattern composed of $2{\times}2cm$ squares. The endpoint of exposure was 300 to 500 J for each grid, depending on the preoperative evaluation results. The results were evaluated by measurement of axillary malodor both pre- and postoperatively using the grading system and iodine starch test. Results : The average follow-up period was 12.8 months. Nineteen patients had a fair-to-good result and ten patients had poor results. The postoperative Minor's test demonstrated that there were remarkable improvements for patients with mild to moderate symptoms. Complications including superficial second degree burns (n=3) were treated in a conservative manner. A deep second degree burn (n=1) was treated by a surgical procedure. Conclusions : Subcutaneous pulsed Nd-YAG laser has many advantages and is an effective noninvasive treatment for mild to moderate axillary osmidrosis.

• Journal of Korean Dental Science
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• 제9권1호
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• pp.19-27
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• 2016

Purpose: Laser treatment has become a popular method in implant dentistry, and lasers have been used for the decontamination of implant surfaces when treating peri-implantitis. This study was performed to evaluate the effects of an Erbium-doped:Yttrium-Aluminum-Garnet (Er:YAG) laser with different settings on machined (MA), sand-blasted and acid-etched (SA), and resorbable blast media (RBM) titanium surfaces using scanning electron microscopy and confocal microscopy. Materials and Methods: Four MA, four SA, and four RBM discs were either irradiated at 40 mJ/20 Hz, 90 mJ/20 Hz, or 40 mJ/25 Hz for 2 minutes. The specimens were evaluated with scanning electron microscopy and confocal microscopy. Result: The untreated MA surface demonstrated uniform roughness with circumferential machining marks, and depressions were observed after laser treatment. The untreated SA surface demonstrated a rough surface with sharp spikes and deep pits, and the laser produced noticeable changes on the SA titanium surfaces with melting and fusion. The untreated RBM surface demonstrated a rough surface with irregular indentation, and treatment with the laser produced changes on the RBM titanium surfaces. The Er:YAG laser produced significant changes on the roughness parameters, including arithmetic mean height of the surface (Sa) and maximum height of the surface (Sz), of the MA and SA surfaces. However, the Er:YAG laser did not produce notable changes on the roughness parameters, such as Sa and Sz, of the RBM surfaces. Conclusion: This study evaluated the effects of an Er:YAG laser on MA, SA, and RBM titanium discs using confocal microscopy and scanning electron microscopy. Treatment with the laser produced significant changes in the roughness of MA and SA surfaces, but the roughness parameters of the RBM discs were not significantly changed. Further research is needed to evaluate the efficiency of the Er:YAG laser in removing the contaminants, adhering bacteria, and the effects of treatment on cellular attachment, proliferation, and differentiation.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제26권1호
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• pp.43-58
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• 1998

The Kwinana Shoreline Fumigation Experiment (KSFE) took place at Fremantle, WA, Australia between January 23 and February 8, 1995. The CSIRO DAR LIDAR measured plume sections from near the Kwinana Power Station (KPS) stacks to up to about 5 km downstream. It also measured boundary layer aerosols and the structure of the boundary layer on some occasions. Both stages A and C of KPS were used as tracers at different times. The heart of the LIDAR system is a Neodymium-doped Yttrium-aluminum-garnet (Nd:YAG) laser operating at a fundamental wavelength of 1064 nm, with harmonics of 532 nm and 355 nm. For these experiments the third harmonic was used because the UV wavelength at 355 nm is eye safe beyond about 50 m. The laser fires a pulse of light 6 ns in duration (about 1.8 m long) and with an energy (at the third harmonic) of about 70 mJ. This pulse subsequently scattered and absorbed by both air molecules and particles in the atmosphere. A small fraction of the laser beam is scattered back to the LIDAR, collected by a telescope and detected by a photo-multiplier tube. The intensity of the signal as a function of time is a measure of the particle concentration as a function of distance along the line of the laser shot. The smoke plume was clearly identifiable in the scans both before and after fumigation in the thermal internal boundary layer (TIBL). Both power station plumes were detected. Over the 9 days of operation, 1,568 plumes scans (214 series) were performed. Essentially all of these will provide instantaneous plume heights and widths, and there are many periods of continuous operation over several hours when it should be possible to compile hourly average plume statistics as well. The results of four days LIDAR observations of the dispersion of smoke plume in the TIBL at a coastal site are presented for the case of stages A and C.

• 한국세라믹학회지
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• 제41권3호
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• pp.190-196
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• 2004

Al 및 Y 질산염 용액에 탄산수소암모늄(NH$_4$HCO$_3$)을 침전제로 사용하여 YAG 분말을 합성하였다. 침전물을 attrition-milling한 결과, $Y_2$O$_3$와 YAG 상이 생성되었으며, 분쇄한 침전물을 110$0^{\circ}C$에서 1시간 하소하여 결정상이 잘 발달된 YAG 단일상 분말을 얻을 수 있었다. 분말의 소결성은 소결조제 SiO$_2$(500ppm Si)의 첨가에 관계없이 매우 우수하였다. 모든 시편은 130$0^{\circ}C$에서 이미 70% 이상의 밀도로 소결되었으며,140$0^{\circ}C$에서도 -83%의 밀도를 나타내었다. SiO$_2$로 도핑한 시편은 도핑하지 않은 시편 보다 치밀화가 약간 향상되었으며, 1$600^{\circ}C$에서 97%의 소결밀도가 얻어졌다.

• Archives of Plastic Surgery
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• 제39권3호
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• pp.232-237
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• 2012

Background : Skin injuries, such as lacerations due to trauma, are relatively common, and patients are very concerned about the resulting scars. Recently, the use of ablative and non-ablative lasers based on the fractional approach has been used to treat scars. In this study, the authors demonstrated the efficacy and safety of ablative fractional resurfacing (AFR) for traumatic scars using a 2,940-nm erbium: yttrium-aluminum-garnet (Er:YAG) laser for traumatic scars after primary repair during the early posttraumatic period. Methods : Twelve patients with fifteen scars were enrolled. All had a history of facial laceration and primary repair by suturing on the day of trauma. Laser therapy was initiated at least 4 weeks after the primary repair. Each patient was treated four times at 1-month intervals with a fractional ablative 2,940-nm Er:YAG laser using the same parameters. Posttreatment evaluations were performed 1 month after the fourth treatment session. Results : All 12 patients completed the study. After ablative fractional laser treatment, all treated portions of the scars showed improvements, as demonstrated by the Vancouver Scar Scale and the overall cosmetic scale as evaluated by 10 independent physicians, 10 independent non-physicians, and the patients themselves. Conclusions : This study shows that ablative fractional Er:YAG laser treatment of scars reduces scars fairly according to both objective results and patient satisfaction rates. The authors suggest that early scar treatment using AFR can be one adjuvant scar management method for improving the quality of life of patients with traumatic scars.