HVPE 법을 활용한 GaN 성장 시 질화처리에 관한 연구

이승훈,이주형,이희애,오누리,이성철,강효상,이성국,양재득,박재화,Lee, Seung Hoon,Lee, Joo Hyung,Lee, Hee Ae,Oh, Nuri,Yi, Sung Chul,Kang, Hyo Sang,Lee, Seong Kuk,Yang, Jae Duk,Park, Jae Hwa 한국결정성장학회 2019 한국결정성장학회지 Vol.29 No.4

HVPE is one of the GaN single crystal manufacturing methods which has been commercially widely used due to its high growth rate. HVPE method consists of a number of processes, in particular the nitridation of the substrate prior to GaN growth has a significant effect on the crystalline quality of the manufactured GaN single crystal. In this study, we investigated the effect of nitridation for crystalline quality of GaN when it was grown on the sapphire substrate. The whole growth conditions except for the nitridation process were the same, and the gas flow rate supplied to the sapphire substrate was variously changed during the nitridation. Here, we examined the effect of nitridation via the surface characterization of GaN single crystal grown by HVPE. HVPE는 GaN 단결정의 제조 방법 중 하나로 빠른 성장 속도가 장점인 상업적으로 널리 사용되는 성장 방법이다. HVPE 법에 의한 GaN 단결정 성장은 여러 공정으로 이루어지며, 특히 GaN 성장 전 기판의 질화 처리는 성장되는 GaN 단결정 품질에 상당한 영향을 미친다. 본 연구에서는 사파이어 기판 위에 GaN 단결정 성장 시 기판의 질화처리가 성장되는 GaN 단결정 품질에 미치는 영향을 알아보고자 하였다. 질화 처리를 제외한 다른 성장 조건은 동일하게 하였고 질화처리 시 기판에 공급되는 가스 유량을 다양하게 변화시킨 후 GaN 박막을 성장시키고, 성장된 GaN의 표면 특성평가를 통하여, HVPE 법에서의 질화처리 효과를 고찰하여 보고자 하였다.

상악 전치부에서 단일 치아 발거 후 즉시 임플란트 식립

이승훈,김영성,김원경,이영규,Lee, Seung-Hoon,Kim, Young-Sung,Kim, Won-Kyung,Lee, Young-Kyoo 대한치주과학회 2007 Journal of Periodontal & Implant Science Vol.37 No.3

Implants placed immediately after tooth extraction have been shown to be a successfully predictable treatment modality. Several clinical papers suggest that placing implants immediately after tooth extraction may provide some advantages: reduction of the number of surgical procedures or patient visits, preservation of the dimensions of alveolar ridge, and shortening of the interval between the removal of the tooth and the insertion of the implant supported restoration. In this case report, three patients received single immediate implant placements to replace a maxillary anterior tooth at the time of extraction. As the three cases were somewhat different, treatment protocols had to be modified as follows: Case 1. Immediate implant placement with healing abutment connection. Case 2. Immediate implant placement with immediate provisionalization. Case 3. Immediate implant placement with Guided Bone Regeneration(GBR). Every implant of these cases was placed in proper position buccolingually, mesiodistally and apicocoronally, The procedures following implantation such as immediate provisionalization and GBR were free of problem. Healing of each case was uneventful. In all cases, treatment outcomes were mostly satisfactory and the results maintained during follow-up periods. However, one case (Case 3) showed some papilla loss due to failure in delicate soft tissue handling during surgery. This papilla loss was compromised by prosthetic means. In conclusion, immediate implant placement in the fresh extraction socket can be a valid and successful option of treatment in aesthetic area. Moreover, this treatment protocol seems to maintain the preexisting architecture of soft and hard tissues in most cases.

실리콘 이종접합 태양전지 특성에 대한 Zn 도핑된 ITO 박막의 일함수 효과

이승훈,탁성주,최수영,김찬석,김원목,김동환,Lee, Seung-Hun,Tark, Sung-Ju,Choi, Su-Young,Kim, Chan-Seok,Kim, Won-Mok,Kim, Dong-Hhwan 한국재료학회 2011 한국재료학회지 Vol.21 No.9

Transparent conducting oxides (TCOs) used in the antireflection layer and current spreading layer of heterojunction solar cells should have excellent optical and electrical properties. Furthermore, TCOs need a high work function over 5.2 eV to prevent the effect of emitter band-bending caused by the difference in work function between emitter and TCOs. Sn-doped $In_2O_3$ (ITO) film is a highly promising material as a TCO due to its excellent optical and electrical properties. However, ITO films have a low work function of about 4.8 eV. This low work function of ITO films leads to deterioration of the conversion efficiency of solar cells. In this work, ITO films with various Zn contents of 0, 6.9, 12.7, 28.8, and 36.6 at.% were fabricated by a co-sputtering method using ITO and AZO targets at room temperature. The optical and electrical properties of Zn-doped ITO thin films were analyzed. Then, silicon heterojunction solar cells with these films were fabricated. The 12.7 at% Zn-doped ITO films show the highest hall mobility of 35.71 $cm^2$/Vsec. With increasing Zn content over 12.7, the hall mobility decreases. Although a small addition of Zn content increased the work function, further addition of Zn content over 12.7 at.% led to decreasing electrical properties because of the decrease in the carrier concentration and hall mobility. Silicon heterojunction solar cells with 12.7 at% Zn-doped ITO thin films showed the highest conversion efficiency of 15.8%.

화재원인조사실무 - 가스폭발사건에서 누출량 계산의 유효성 검토

이승훈,Lee, Seung-Hun 한국화재보험협회 2015 防災와 保險 Vol.157 No.-

돈분뇨 슬러리 액비저장조내 침전물 특성 연구

이승훈,정광화,김중곤,곽정훈,한덕우,Lee, Seung-Hun,Jeong, Kwang-Hwa,Kim, Jung-Gon,Khan, Modabber ahmerd,Kwag, Jung-Hun,Han, Deug-Woo 한국축산환경학회 2014 한국축산시설환경학회지 Vol.20 No.4

Liquid fertilization of pig manure slurry is very useful treatment method to recycle organic waste matter as a valuable fertilizer. The solids precipitate and accumulated at the bottom of liquid fertilization tank. The content of nitrogen and phosphate are higher in sediment than pig manure slurry. The pH of sediment was 7.53. S-COD/T-COD ratio of pig manure slurry and sediment were 0.477, 0.29, respectively. The moisture content of sediment of pig manure slurry and sediment were 80.45~83.82%, 97%, respectively. The content of organic matter of sediment was 8.79~10.56%. The content of nitrogen and phosphate of sediment and pig manure slurry were 9,000~11,100 mg/L, 9,100~11,100 mg/L, respectively. The particle size of pig manure slurry was distributed from 2 mm to 0.125 mm. On the other hand. the particle size of sediment was under 0.125 mm.

소아 폐쇄성 수면무호흡증후군 1례

이승훈,권순영,이상학,장지원,김진관,신철,Lee, Seung-Hoon,Kwon, Soon-Young,Lee, Sang-Hag,Chang, Ji-Won,Kim, Jin-Kwan,Shin, Chol 대한수면의학회 2004 수면·정신생리 Vol.11 No.1

페쇄성 수면무호흡증후군은 다양한 원인에 의하여 발생할 수 있으며, 특히 편도 및 아데노이드 비대증은 소아에서 가장 흔한 원인이다. 편도 및 아데노이드 비대증에 의하여 발생한 폐쇄성 수면무호흡증후군은 다양한 증상과 함께 행동 장애, 야뇨증, 성장 및 발달장애, 폐성심, 고혈압과 같은 다양한 합병증을 초래할 수 있다. 이러한 이유로 임상적으로 소아에서 폐쇄성 무호흡증상이 수면 중에 관찰되면 적절한 진단과정 후에 상태에 따라서 적극적인 치료가 필요하다. 소아에서의 치료는 편도 및 아데노이드 비대증에 의한 경우 수술적인 제거를 통하여 80% 이상에서 호전을 관찰할 수 있다. 그러나 편도 및 아데노이드 제거 후에도 증상이 남아있거나 수술적인 치료가 불가능한 환아에 대해서는 체중조절, 수면자세의 변화와 같은 생활습관의 조절 및 지속적 기도양압호흡기를 이용하여 추가적인 치료를 시행할 수 있다. 저자들은 수면다원검사상 심한 폐쇄성 수면무호흡이 관찰되어 편도 및 아데노이드 절제술을 시행한 후 증상의 호전이 있었으나, 장기간 추적관찰 후 재발한 수면무호흡과 코골이를 조절하기 위하여 생활습관의 개선교육과 자동화 기도양압호흡기로 치료한 1례를 경험하였기에 보고한다. The obstructive sleep apnea syndrome can occur due to various etiologies in children. In otherwise healthy children, adenotonsillar hypertrophy is the leading cause of childhood obstuctive sleep apnea. Obstructive sleep apnea caused by adenotonsillar hypertrophy can lead to a variety of symptoms and sequelae such as behavioral disturbance, enuresis, failure to thrive, developmental delay, cor pulmonale, and hypertension. So if obstructive sleep apnea is clinically suspected, proper treatment should be administered to the patient after diagnostic examinations. More than 80% improvement is seen in symptoms of obstructive sleep apnea caused by adenotonsillar hypertrophy in children after tonsillectomy and adenoidectomy. However, when it is impossible to treat the patient using surgical methods or residual symptoms remained after tonsillectomy and adenoidectomy, additional treatments such as weight control, sleep position change, and continuous positive airway pressure (CPAP), should be considered. This paper reports a case using weight control and Auto-PAP to control mild sleep apnea and snoring, which in long-term follow-up were not resolved after tonsillectomy and adenoidectomy for severe obstructive sleep apnea.

화재원인조사실무 - 탱크 및 배관 등 작업에 의한 폭발

이승훈,Lee, Seung-Hun 한국화재보험협회 2013 防災와 保險 Vol.150 No.-

화재원인조사실무 - 화재조사 지표로서 유리파괴 분석의 법공학적 가치

이승훈,Lee, Seung-Hun 한국화재보험협회 2014 防災와 保險 Vol. No.

소아 폐쇄성수면무호흡증후군

이승훈,최지호,Lee, Seung-Hoon,Choi, Ji-Ho 대한수면의학회 2005 수면·정신생리 Vol.12 No.2

Approximately 1% to 3% of all children have obstructive sleep apnea syndrome (OSAS). OSAS in children can lead to a variety of symptoms and sequalae; impairment of development and quality of life, behavioral and personality disturbance, learning problem, cor pulmonale and hypertension. Diagnosis and treatment of OASA for children are different from those for adults in many respects. Adenotonsillar hypertrophy is major cause of childhood OSAS. Overnight polysomnography in a sleep laboratory is the gold standard for diagnosing childhood OSAS. However, because full polysomnography in children may be difficult to obtain, expensive, and inconvenient, other methods to diagnose OSAS have been investigated. Adenotonsillectomy is the most common surgical treatment of childhood OSAS. But if residual symptoms remained after adenotonsillectomy, it should be considered to additional treatment such as weight control, sleep positional change, and continuous positive airway pressure (CPAP).

음성, 성문 및 호흡 통합 검사 시스템의 개발

이승훈,정원혁,최홍식,김수찬,임재중,김덕원,Lee, Seung Hoon,Jung, Won Hyuk,Choi, Hong-Shik,Kim, Soo-Chan,Im, Jae-Joong,Kim, Deok-Won 한국음성학회 2005 음성과학 Vol.12 No.4

Voice is made by systemic interaction of respiration, vocalization, articulation and resonation. There is no existing multi-channel voice analysis system to assess voice and respiration simultaneously. The most existing systems consist of. vocal fold vibration measurement such as stroboscopy, EGG (electroglottography) or laryngeal electromyography and voice analysis system. Since respiration has close relationship with voice simultaneous analysis of both vocal cord vibration and respiration are essential. In this study, a four channel integrated system are developed for acoustic analysis through microphone, vocal fold vibratory analysis using EGG, and respiratory analysis using two channel RIP (respiratory inductive plethysmography).