• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.52-59
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• 1997

Design and performance of principal four ICs for the 10-Gb/s optical communication system are presented. AlGaAs/GaAs HBTs are basic devices to implement a laser diode driver, apre-amplifier, and a limiting amplifier, and GaInP/GaAs HBTs are used for an AGC amplifier. We fbricated 11.5-GHz LD driver, a pre-amplifier, and a limiting amplifier, an dGaInP/GaAs HBTs are used for an AGC amplifier. We fabricated LD deriver, 10.5 GHz pre amplifier, 7.2 GHz AGC amplifier, and 10.3 GHz limiting amplifier, optimized circuit design and the stabilized MMIC fabrication process.

• The Journal of Pediatrics of Korean Medicine
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• v.29 no.4
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• pp.29-38
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• 2015

Objectives We aimed to identify the effectiveness of photobiomodulation using low level laser therapy (LLLT), light emitting diode (LED) and others on the growth of the length of the growth plate by reviewing literatures. Methods We searched literatures using PubMed, Science Direct, CINAHL, Korea Traditional Knowledge Portal (KTKP), Oriental Medicine Advanced Searching Integrated System (OASIS), China Knowledge Resource Integrated Database (CNKI), Japan Science and Technology Information Aggregator, Electronic (J STAGE), and Japan National Institute of Informatics Scholarly and Academic Information Navigator (CiNii) using the keywords "Growth plate" "Epiphyseal growth" "Epiphyseal plate" and "Laser", "light emitting diode (LED)", "near-infrared light", and "photobiomodulation". Search range included only original article which provided English abstract were selected. The search strategy contained no language limitation. Results A total 556 studies were found. Then, 551 were excluded by scanning titles and abstracts and finally 5 articles were selected. Five articles were RCTs using rodents. Two of the 5 articles used InGaAlP Laser (630-685 nm), and the other 3 articles used GaAlAs Laser (780, 820, and 870 nm) to investigated the effects of LLLT on the growth of the length of the epiphyseal cartilage and the number of chondrocytes and thickness of each zone of the epiphyseal cartilage. Two articles concluded that LLLT had a beneficial effect on the longitudinal growth of the growth plate. In growth of the epiphyseal plate, there were no significant differences in others. Conclusions It is might that LLLT influenced on the growth of epiphyseal plate by positive affect. However, further rigorous RCTs are warranted.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.249-249
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• 1999

GaN과 같은 III-nitride 반도체 관한 식각 기술의 연구는 blue-emitting laser diode(LD)를 위한 경면(mirror facet)의 형성뿐만아니라 새로운 display 용도의 light emitting diodes (LED), 고온에서 작동되는 광전소자 제조 등에도 그 중요성이 증대되고 있다. 최근에는 III-nitride 물질의 높은 식각속도와 미려하고 수직한 식각형상을 이루기 위하여 ECR(Electron Cyclotron Resonance)이나 ICP(Inductively Coupled Plasma)와 같은 고밀도 플라즈마 식각과 CAIBE(Chemically assisted ion beam etching)를 이용한 연구가 진행되고 있다. 현재 제조되어 지고 있는 LED 및 LD와 같은 광소자의 구조의 대부분은 p-GaN/AlGaN/InGaN(Q.W)/AlGaN/n-GaN 와 같은 여러 층의 형태로 이루어져 있다. 이중 InGaN는 광소자나 전자소자의 특성에 영향을 주는 가장 중요한 부분으로써 현재까지 보고된 식각연구는 undoped GaN에 대부분 집중되고 있고 이에 비해 소자 특성에 핵심을 이루는 InGaN의 식각특성에 관한 연구는 미흡한 상황이다. 본 연구에서는 고밀도 플라즈마원인 ICP 장비를 이용하여 InGaN를 식각하였고, 식각에는 Cl2/CH4, Cl2/Ar 플라즈마를 사용하였다. InGaN의 식각특성에 영향을 미치는 플라즈마의 특성을 관찰하기 위하여 quadrupole mass spectrometry(QMS)와 optical emission spectroscopy(PES)를 사용하였다. 기판 온도는 5$0^{\circ}C$, 공정 압력은 5,Torr에서 30mTorr로 변화시켰고 inductive power는 200~800watt, bias voltage는 0~-200voltage로 변화시켰으며 식각마스크로는 SiO2를 patterning 하여 사용하였다. n-GaN, p-GaN 층 이외에 광소자 제조시 필수적인 InGaN 층을 100% Cl2로 식각한 경우에 InGaN의 식각속도가 GaN에 비해 매우 낮은 식각속도를 보였다. Cl2 gas에 소량의 CH4나 Ar gas를 첨가하는 경우와 공정압력을 감소시키는 경우 식각속도는 증가하였고, Cl2/10%Ar 플라즈마에서 공정 압력을 감소시키는 경우 식각속도는 증가하였고, Cl2/10%CHF3 와 Cl2/10%Ar 플라즈마에서 공정압력을 15mTorr로 감소시키는 경우 InGaN과 GaNrks의 선택적인 식각이 가능하였다. InGaN의 식각속도는 Cl2/Ar 플라즈마의 이온에 의한 Cl2/CHF3(CH4) 플라즈마에서의 CHx radical 형성에 의하여 증가하는 것으로 사료되어 진다.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.4
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• pp.62-74
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• 2017

Objectives : The purpose of this study is to investigate the effect of laser therapy for diabetic ulcer by using methods of systematic review. Methods : In this review, PubMed, Cochrane library, Web of Science, CNKI, CiNii, J-STAGE, NDSL and OASIS were used as the search engines. The search period is from the start date of the search engine to October 3, 2016. Randomized controlled trials(RCTs) using laser therapy for diabetic ulcer were searched and extracted by two independent researchers. Risk of bias(RoB) of Cochrane was used to assess methodological quality of studies. Results : Finally, five RCTs were selected. The follow-up period ranged from 15 days to 20 weeks. InGaAlP laser, GaAlAs laser and light emitting diode(LED) were used to treat diabetic ulcer. The clinical trials used sham laser irradiation or standard treatment as control in comparison to laser therapy. The endpoints included ulcer size, rate of healing and time to healing with follow-up period. The RCTs demonstrated therapeutic outcomes with no adverse effect. Most items of RoB were unclear and methodological quality was low. Conclusions : Our analysis suggests that laser therapy has therapeutic effects for diabetic ulcer. However, more systematic and stringent clinical trials will be required.

• The Journal of Korean Physical Therapy
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• v.15 no.3
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• pp.239-250
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• 2003

This study was performed to investigate the effect of low power laser irradiation on Substance P(SP) expression in the burned skin of the rats. Burns of about 3cm in diameter were created with $75^{\cric}C$ water on the back of the rats, and the lesion of experimental group were irradiated on days 1, 2, 3 and 4 postwounding. Control leasions were not irradiated. After burns, low power laser irradiation was applied by using 1000Hz, 830nm GaAlAs(Gallium-aluminum-arsenide) semiconductor diode laser. The expression of evaluated Substance P(SP) immunohistochemistry on rabbit anti-SP The results of this study wereas follows 1. The Substance P was expressed in the lamina I and II of dorsal horn of spinal cord. In expression of SP, the lesion of control group made SP to more induce significantly than experimental leasions. 2. SP immunoreactivity in burned leasion of spinal cord were decreased markedly 4 days after burns, and decreased gradually from 1 day to 2 days in burns which is laser irradiation These data suggest that low power laser have a pain release effect in the burned skin of the rats.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.313-320
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• 2021

Objective: The purpose of this study was to evaluate the effects of chewing gum and low-level laser therapy in alleviating orthodontic pain induced by the initial archwire. Methods: Patients with 3-6 mm maxillary crowding who planned to receive non-extraction orthodontic treatment were recruited for the study. Sixty-three participants (33 females and 30 males) were randomly allocated into three groups: laser, chewing gum, and control. In the laser group, a gallium aluminum arsenide (GaAlAs) diode laser with a wavelength of 820 nm was used to apply a single dose immediately after orthodontic treatment began. In the chewing gum group, sugar-free gum was chewed three times for 20 minutes-immediately after starting treatment, and at the twenty-fourth and forty-eighth hours of treatment. Pain perception was measured using a visual analog scale at the second, sixth, and twenty-fourth hours, and on the second, third, and seventh days. Results: There were no statistically significant differences between the groups at any measured time point (p > 0.05). The highest pain scores were detected at the twenty-fourth hour of treatment in all groups. Conclusions: Within the limitations of the study, we could not detect whether low-level laser therapy and chewing gum had any clinically significant effect on orthodontic pain. Different results may be obtained with a higher number of participants or using lasers with different wavelengths and specifications. Although the study had a sufficient number of participants according to statistical analysis, higher number of participants could have provided more definitive outcomes.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.256-256
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• 2010

투명전극부터 디스플레이 산업에 이르기까지 광범위하게 응용되어지고 있고 개발되어지고 있는 투명전도산화물(TCO)은 ZnO, In2O3, SnO2 등을 기본으로 하는 n-type 재료가 대부분이다. 그러나 투명전도 산화물을 이용한 light emitting diode(LED), 투명한 태양전지, p-형 TFT와 같은 투명전자소자의 개발을 위해서는 p-type 소재가 필수적이다. p-type TCO 소재는 비교적 연구 개발 실적이 매우 부진한 실정이었다. 1997년 넓은 밴드갭을 가지는 ABO2(delafossite) 산화물이 p-type으로서 안정적이라는 것을 보고함에 따라 이에 대한 연구가 활발히 진행되고 있다. 현재 ABO2 형태를 가진 Delafossite구조 산화물이 가장 유망한 p-type 투명전도체 소재로 거론되고 있다. Delafossite 구조가 p-type 투명전도체에 적합한 결정구조인 이유는 밴드갭이 넓고 공유결합에 유리하기 때문이다. Delafossite구조는 상온에서 2종류의 polytype(상온에서 Rhombohedaral구조와 hexagonal 구조)이 존재하며 이들은 각각 3R 및 2H의 결정 구조를 가지고 있다. ABO2의 delafossite구조에서 Cu+의 배열은 c-축을 따라 Cu-O-Cr-O-Cu의 연속적인 층 구조로서 2차원연결로 보여 진다. 보고된 Cu- base delafossite구조를 가지는 재료들은 CuAlO2, CuGaO2, CuInO2 등 여러가지가 있다. 본 연구에서는 PLD를 이용하여 c-plane 사파이어 기판위에 성장된 delafossite구조인 CuCrO2박막의 특성을 알아보았다. p-type 특성을 위하여 CuCrO2에 Zn를 첨가하였으며 그에 따른 구조적 전기적 특성을 조사하였다. 성장온도와 산소분압을 $500{\sim}700^{\circ}C$, 0~10mTorr로 변화시켜 특성을 연구하였다. 성장온도 $700^{\circ}C$, 산소분압 10mTorr에서 c-plane 사파이어 기판위에 c-축 배향의 에피성장된 CuCrO2:Zn 박막을 얻을 수 있었다. Mg를 도핑함에 따른 p-type 특성보다 현저히 떨어지는 것을 확인하였다. 또한 동일한 조건임에도 특정한 이차상의 존재를 통해 도핑된 Zn의 위치를 추측할 수 있었다. 온도와 분압에 따른 결정성과 표면상태를 SEM을 통해서 확인하였다.