• 대한한방소아과학회지
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• 제23권3호
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• pp.193-206
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• 2009

Objectives The purpose of this study is to evaluate the effects of Low Level Laser Therapy on Atopic dermatitis symptoms. Methods 19 patients (7 men, 12 women) were involved in this study. The intensity of SCORAD index (Erythema/darkening, Edema/papulation, Oozing/crust, Excoriation, Lichenification/prurigo, Dryness) and the symptom of SCORAD index (Pruritus) in two regions were measured. One region was treated by LLLT, the other region was not treated. Then a comparative study of index score of two regions was analyzed. Results After treatment, there were statistically significant differences in Edema/papulation, Excoriation (p<0.001), Oozing/crust (p<0.01), and Pruritus(p<0.05) index. Conclusions Based on the results, we concluded that LLLT is an effective in the treatment of atopic dermatitis. Also, further controlled studies with clinical cases of appropriate treatment time, wavelength, and intervals are needed.

• 대한치과교정학회지
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• 제48권2호
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• pp.90-97
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• 2018

Objective: The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires. Methods: Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides. Results: Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires. Conclusions: A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.

• 한국항공우주학회지
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• 제48권6호
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• pp.479-487
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• 2020

본 논문에서는 라만 분광법과 레이저 유도 플라즈마 분광법(LIPS)을 단일 유닛으로 결합한 새로운 형태의 이중 펄스 레이저 시스템을 제안하였다. 본 연구는 라만 분광법으로부터 분자 신호를 추출하면서, 동시에 레이저 유도 플라즈마 방출 신호를 향상시키고자 하였다. 달의 대기압과 같은 저압 조건에서는 플라즈마 신호 검출은 낮은 전자 밀도와 짧은 지속시간, 빠른 플라즈마 팽창 때문에 어려움을 마주치게 된다. 또한, 우주 탐사를 목표로 하는 검출 시스템의 통합에서, 레이저 시스템의 무게 최소화는 payload의 무게 측면에서 중요하다. 0.07 torr 미만의 저압 조건에서 높은 분해능의 스펙트럼 데이터를 제공하는 본 연구의 동시 분자 및 원자 검출방식은 8개의 암석을 이용하여 증명되었다. 이중 펄스 레이저로부터 생성된 연속된 플라즈마는 종래의 플라즈마 분광과 비교하여 방해석의 산소와 칼슘 신호를 2배 향상시킬 수 있었다.

• 전기학회논문지
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• 제58권8호
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• pp.1580-1584
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• 2009

We have theoretically analyzed the monolithic integration of vertical cavity lasers with depleted optical thyristor (VCL-DOT) structure and experimentally demonstrated optical logic gates such as AND-gate, OR-gate, and INVERTER implemented by VCL-DOT for an optical programmable gate array. The optical AND and OR gates have been realized by changing a input bias of the single VCL-DOTs and all kinds of optical logic functions are also implemented by adjusting an intensity of the reference input beams into the differential VCL-DOTs. To achieve the high sensitivity, high slope efficiency and low threshold current, a small active region of lasing part and a wide detecting area are simultaneously designed by using a selective oxidation process. The fabricated devices clearly show nonlinear s-shaped current-voltage characteristics and lasing characteristics of a low threshold current with 0.65 mA and output spectrum at 854 nm.

• Journal of the Optical Society of Korea
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• 제16권2호
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• pp.101-106
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• 2012

We demonstrate a cost effective broadcast signal transmission at 1.25-Gb/s with 100 GHz channel spacing based on a broadband light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON). The BLS is implemented by using mutually injected Fabry-Perot laser diodes (MI F-P LDs). The error-free transmission without a forward error correction (FEC) is achieved by its low relative intensity noise (RIN). The number of usable modes is determined by RIN and/or extinction ratio (ER) in the spectrum sliced light output.

• 분석과학
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• 제8권4호
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• pp.779-786
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• 1995

Environmental and industrial aerosols can be analyzed on-line by laser plasma spectroscopy. The main problem in direct (no preparation or presorting) aerosol analysis is the extensive spectral fluctuations. A method to partially solve this problem is proposed. It is based on single shot measurements and application of a special rejection algorithm. The major factors that influence the spectral variations are discussed, in relation to the correction possibility by a rejection program. The method works well when average intensity of the single spectra is relatively high, as compared to detector's saturation limit. If intensities are too low, the accumulation of readout noise is critical, and no improvement is expected.

• 마이크로전자및패키징학회지
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• 제23권3호
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• pp.37-41
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• 2016

본 논문에서는 긴 작동거리(working distance, WD)를 가지는 근적외선 형광 이미징 시스템을 소개하고, gain, 노출시간, 작동거리, 확대배율 등 측정 변수에 의한 형광 영상의 차이에 대해 분석하였다. 노출시간이 길수록, 확대배율이 클수록 형광신호는 더욱 강해지고, gain이 클수록 형광신호도 강해지지만, 배경신호도 함께 증가하여 SBR은 나빠질 수 있다. 제안한 시스템은 레이저 조사 방식으로 인해 작동거리가 짧은 경우 레이저 조사 영역의 강도 분포가 균일하지 못해서 형광신호가 약해지며, 그에 따른 해결방안을 제안하였다.

• Journal of Periodontal and Implant Science
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• 제52권1호
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• pp.39-53
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• 2022

Purpose: This study evaluated the systemic and local effects of doxycycline (DOX) and low-intensity laser (LIL) treatment as adjuvants to scaling and root planing (SRP) in the treatment of experimental periodontitis in rats. Methods: The sample consisted of 180 male rats (Rattus norvegicus albinus, Wistar), of which 30 did not receive induction of periodontal disease (negative control [NC] group) and 150 received induction of periodontal disease in the lower first molar. After 7 days, the ligature was removed, and the animals were divided into the following groups: NT (no treatment), SRP (SRP), DOX (SRP and DOX irrigation), LIL (SRP and laser irradiation), and DOX+LIL (SRP, DOX, and LIL). The animals were euthanized at 7, 15, and 30 days; thereafter, biochemical, radiographic, histological, and immunohistochemical analyses were performed. Results: In the intragroup analysis, lower concentrations of α-1-glycoprotein acid (α-1-Ga) and complement 3 (C3) were observed in the DOX+LIL group than in all other groups at all time points, as well as lower levels of complement 4 (C4) at 15 and 30 days (P<0.001). Less bone loss was observed in the DOX, LIL, and DOX+LIL groups than in the NC and SRP groups at all time points (P<0.001). There was a smaller number of tartrate-resistant acid phosphatase (TRAP)-positive cells in the DOX+LIL group than in the other groups at all time points (P<0.001). Positive correlations were observed between the systemic levels of α-1-Ga, C3, and C4 and the number of TRAP-positive cells. Conclusions: The combination of DOX with LIL as SRP adjuvants was effective both systemically and locally for the treatment of experimental periodontitis in rats.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.102-102
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• 1999

Visible photoluminescence(PL) in si-implanted SiO2 films on crystaline silicon were observed. Thermal oxide films of 1 ${\mu}{\textrm}{m}$ thickness on P-type crystal silicon were made and si+ ions were implanted with 200keV acceleration voltage on ti. Argon laser (wavelength 488nm) and PM tube were used for PL measurements. As annealing time increased at low temperature, the visible PL intensity are increased and the peak positions are changed. On the other hand, with increasing annealing time at high temperature, the visible PL intensity are disappeared. From the PL peaks and intensity changes, XRD results, and TEM observations, we will discuss the origin of PL in Si+-implanted SiO2 films with oxygen righ defects and silicon rich defects.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.694-697
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• 2016

Up-converted phase noise, which is induced by the low-frequency relative intensity noise (RIN) of a laser through AM-PM conversion within a photodetector (PD), is first measured here by means of a cross-correlation method. Our proposed measurement system can isolate the RIN-induced phase noise from noise contributions of other components, such as amplifiers, modulators, and mixers. In particular, shot noise and thermal noise generated from the PD are also suppressed by this method, so that standalone characteristics of the RIN-induced phase noise can be obtained. Experimental results clearly show the quantitative relationship between the RIN-induced phase noise and the incident optical power of the PD. Our findings indicate that the least RIN-induced phase noise appeared at the saturation point of the PD, which is about -162 dBc/Hz at 10 kHz offset.