전기차 응용을 위한 수직형 GaN 전력반도체 기술 동향

이형석,배성범,H.S. Lee,S.B. Bae 한국전자통신연구원 2023 전자통신동향분석 Vol.38 No.1

The increasing demand for ultra-high efficiency of compact power conversion systems for electric vehicle applications has brought GaN power semiconductors to the fore due to their low conduction losses and fast switching speed. In particular, the development of materials and core device processes contributed to remarkable results regarding the publication of vertical GaN power devices with high breakdown voltage. This paper reviews recent advances on GaN material technology and vertical GaN power device technology. The GaN material technology covers the latest technological trends and GaN epitaxial growth technology, while the vertical GaN power device technology examines diodes, Trench FETs, JFETs, and FinFETs and reviews the vertical GaN PiN diode technology developed by ETRI.

Analysis of the Oxidative Stress-Related Transcriptome from Capsicum annuum L.

이형석,이상호,김호방,Nam Houn Lee,안정선 한국식물생명공학회 2010 식물생명공학회지 Vol.37 No.4

For the massive screening of the genes related to oxidative stress, a cDNA library was constructed from hot pepper (Capsicum annuum L. cv. Nockkwang) leaves treated with methyl viologen. From this library, 1,589 cDNA clones were sequenced from their 5' ends. The sequences were clustered into 1,252 unigenes comprised of 152 contigs and 1,100 singletons. Similarity search against NCBI protein database identified 1,005 ESTs (80.3%) as Known, 197 ESTs (15.7%) as Unknown, and 50 ESTs (3.99%) as No hit. In the ESTs, oxidative stress-related genes such as ascorbate peroxidase, catalase, and osmotin precursor were highly expressed. The cDNA microarray containing 1,252 unigenes was constructed and used to analyze their expression upon methyl viologen treatment. Analyses of the hybridization revealed that various stress-related genes such as peroxidase, tyrosine aminotransferase, and omega-6 fatty acid desaturase, were induced and some metabolism related genes such as aldolase and ketol-acid reductoisomerase, were repressed by methyl viologen treatment, respectively. The information from this study will be used for further study on the functional roles of oxidative stress-related genes and signaling network of oxidative stress in hot pepper.

일측성 광대뼈골절 환자에서 수평계와 자를 이용한 변위 교정의 간단한 파악법

이형석,이경석,김준식,김남균,Yi, Hyung-Suk,Lee, Kyung-Suk,Kim, Jun-Sik,Kim, Nam-Gyun 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.2

Purpose: The zygoma is a key element which composes the facial contour. Zygomatic fracture induces facial asymmetry. We use radiologic evaluation or inspections mainly for identification of symmetry after reduction depressed zygomatic fracture. But the disadvantages of such methods are time-consuming and complicated process. So we tried to develop a new testing method with a ruler and a level. Methods: In unilateral depressed zygomatic fracture patient, parallel to the patient's head to make sure lay horizontaly. Put the leg of a ruler on the malar eminence so that it is at the same distance from the facial midline. Then take the level of malar eminence as put the level above the ruler. This process was performed before and after the reduction. Results: We were able to fix with plate and screw after checking the results of reduction fast and easily. Good results were obtained at post-operative radiologic evaluation. Conclusion: We can easily get the ruler and level around life. This method is not only simple but also shorttime process compared with other method-radiologic evaluation or inspection. And the operator can explain the results to the patients easily and objectively. Authors obtained the good results with this new method, and would introduce it for another method of identifying the result of reduction in depressed zygomatic fractures.

기관피부누공에 대한 임상적 고찰

이형석,김현수,심봉택,태경,박철원,Lee, Hyung-Seok,Kim, Hyun-Soo,Shim, Bong-Taek,Tae, Kyung,Park, Chul-Won 대한기관식도과학회 1995 大韓氣管食道科學會誌 Vol.1 No.1

The tracheocutaneous fistula(TCF) may develop infrequently as a complication after tracheostomy. Prolonged tracheostomy tube dependence increases the risk of TCF developing, and in growth of stratified squamous epithelium lines the furrow connecting the tracheal mucosa and the skin, accounting for persistence of the fistulous tract. Such fistulas are a nuisance and create nursing and social problems including poor hygiene, aspiration, difficulty with speech, and depletion of pulmonary reserve. Surgical closure has generally been successful by primary closure, fistulectomy with primary closure, and closure by secondary intention following excision of the tracheocutaneous fistula. No large series compares the efficacy of these techniques and each has its own merits. Recent literature has purposed to minimizing complications. For ten years, from January 1985 to December 1994, the authors experienced 25 cases of TCF which were analyzed in respect to incidence and interval of cannulation, duration between decanulation and fistular closure, precedent disease, closure methods, and complications of TCF repair.

Sulfur Dioxide 가스 흡입 후 흰쥐 기관 점막에서 Laminin의 발현에 대한 연구

이형석,유연희,조석현,김경래,정호삼,Lee, Hyung-Seok,Yu, Yean-Hee,Cho, Seok-Hyun,Kim, Kyung-Rae,Chung, Ho-Sam 대한기관식도과학회 2000 大韓氣管食道科學會誌 Vol.6 No.1

Background and Objectives : The concentration of sulfur dioxide($SO_2$) gas in the ambient air appears increasing in the industry and urban area day by day. It was known that $SO_2$ is noxious gas. $SO_2$ can be irritating to the eyes, nose, throat, upper respiratory tract and skin. It produces sulfurous acid on contact with water and is extremely irritating to the nasopharynx and respiratory tract. Laminin is a family of extracellular matrix glycoproteins localized in the basement membrane that separates epithelial cells from the underlying stroma. The biological activities of laminin are to promote cell migration, wound healing, growth and differentiation. Meterials and Methods : The histologic changes and the expression of laminin in tracheal mucosa sacrificed at every weeks (to 7 weeks) after continued $SO_2$ exposure of 250ppm for 30 minutes a day were studied in rats. Results : Pathologic tissue was formed at the tracheal mucosa and the underlying tissue by the infiltration of monocytes and epithelium was transformed to the single cell layered epithelium above 5 weeks after exposure. At the 6 weeks after exposure, epithelial cells were partially lost and epithelial cell layer was transformed to be leaf-shaped. Submucosal tissue was transformed to be lymphatic tissue. An intense positive staining for laminin was found in apical cytoplasm and lateral surface of the normal epithelial cells and basement membrane but at the 5 and 6 weeks after exposure, laminin activity was decreased to the moderate activity. At the 7 weeks after exposure, laminin activity was decreased to the weak activity. Conclusion : Our finding suggests that $SO_2$ makes histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin. Longer duration of the exposure of $SO_2$ makes more histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin.

둔부에 발생한 골수외 형질세포종 - 증례 보고 -

이형석,김정렬,Lee, Hyung-Seok,Kim, Jung-Ryul 대한근골격종양학회 2009 대한골관절종양학회지 Vol.15 No.1

골수외 형질세포종은 아주 드물게 발생하는 종양으로, 전체 형질 세포 종양의 3~5 %를 차지하며 상부 호흡기관에서 주로 발생한다. 그 외 드물게 위장관, 방광, 중추 신경계, 유방, 갑상선, 고환, 타액선, 임파선, 피부 등에서 발생한 증례보고가 있다. 저자들은 49세 남자의 대둔근에서 발생한 골수외 형질세포종 1예를 경험하였기에 이를 문헌 고찰과 함께 보고하는 바이다. Extramedullary plasmacytoma is extremely rare, constitute 3 to 5 % of plasma cell malignancies and commonly occur in the upper aerodigestive tract. Several case studies of extramedullary plasmacytoma occurring in unusual location are reported; stomach, bladder, central nervous system, breast, thyroid, testis, salivary gland and skin. Here, we present a case of an extramedullary plasmacytoma of the right gluteus maximus muscle in a 49-year-old man.

임베디드 운영체제 커널 기술 동향

이형석,정영준,Lee, H.S.,Jung, Y.J. 한국전자통신연구원 2006 전자통신동향분석 Vol.21 No.1

임베디드 시스템이라 함은 우리가 생활하는 주변에서 흔히 접할 수 있고, 얘기만 들어도 쉽게 이해할 수 있는 PDA, 스마트폰, MP3 플레이어, 셋톱박스 등의 정보가전 기기들을 비롯하여 로봇, 텔레매틱스, 공장자동화, 군사기기와 센서노드에 이르는 디지털기기들에 컴퓨터가 내장되어 들어가 있는 시스템을 의미한다. 이러한 임베디드 시스템에 사용되는 임베디드 운영체제는 VxWorks, VRTX, pSOS, QNX와 같은 전용 RTOS에만 의존해 왔으나, 최근의 발전된 하드웨어와 네트워크 인프라로 인하여 보다 낮은비용으로 쉽고 빠르게 개발하며 범용으로 사용될 수 있는 임베디드 리눅스를 활용하는사례가 늘어나고 있는 추세에 있다. 이렇게 각광 받기 시작하는 임베디드 리눅스의 커널 기술과 관련한 대표적 관련 기술에 대해 설명한다.

악성 골 종양으로 오인된 급속 파괴형 고관절증 - 증례 보고 -

이형석,김정렬,Lee, Hyung-Seok,Kim, Jung-Ryul 대한근골격종양학회 2008 대한골관절종양학회지 Vol.14 No.2

급속 파괴형 고관절증(Rapidly destructive coxarthrosis)은 고관절에 발생하여 급속한 골파괴를 일으키며 현재까지 확실한 원인이 밝혀지지 않은 드문 질환이다. 임상적으로 극심한 고관절 통증과 파행을 나타내며, 방사선학적으로 수개월 내에 급속한 대퇴골두의 파괴를 일으키므로 류마토이드 관절염, 세균성 관절염, 신경병성 관절증 및 골종양과 감별을 요한다. 저자들은 우측 대퇴골두에 발생하여 4개월만에 급속한 골파괴성 병변을 보여 악성 골종양으로 오인되어 타 병원으로부터 전원 되었던 80세 여자 환자의 급속 파괴형 고관절증을 보인 증례를 경험하였기에 이를 문헌 고찰과 함께 보고하는 바이다. Rapid destructive hip osteoarthritis is a rare subset of osteoarthritis with rapid destruction of the hip joint within months of the onset of symptoms. The entity simulates rheumatoid arthritis, septic arthritis, neuropathy or malignant bone tumor. We report a case of rapidly destructive coxarthrosis of the right hip joint initially misdiagnosed as a malignant bone tumor at outside hospital in a 80-year-old woman.

악성 흑색종의 예후 인자에 대한 분석

이형석,박종혁,함동훈,김정렬,Lee, Hyung-Seok,Park, Jong-Hyuk,Ham, Dong-Hun,Kim, Jung-Ryul 대한근골격종양학회 2009 대한골관절종양학회지 Vol.15 No.2

목적: 최근 발생빈도가 증가하고 있는 악성 흑색종의 치료 결과를 분석하여 장기 예후에 영향을 미치는 인자를 알아보고자 하였다. 대상 및 방법: 1997년 3월부터 2004년 3월까지 악성 흑색종으로 진단 받았고 5년 이상 추시가 가능하였던 51예를 대상으로 후향성 연구를 하였으며, 평균연령은 49.4세였다. 연구 방법으로는 나이, 성별, 발생 부위, 종양의 두께, 주위 림프절 전이여부, 면역화학 요법의 시행 유무에 따른 5년 생존율을 비교하였고, 전이 및 국소재발 유무를 조사하였다. 결과: 발병 연령이 65세 미만인 경우 5년 생존율은 88.5%였고, 65세 이상에서는 88.0%였다. 남자의 5년 생존율은 62.5%였으며, 여자는 100%였다. 발생 부위에 따른 5년 생존율은 상지가 100%, 하지가 80.0%, 기타 부위가 100%였다. Clark stage III이하에서는 100% 5년 생존율을 보였고, IV이상에서는 79.3%였다. 주위 림프절로의 전이가 있었던 경우 5년 생존율은 66.7%였고, 림프절 전이가 없었던 경우는 94.9%였다. 결론: 악성흑색종의 예후에 영향을 미치는 인자로 성별(남자), 발생 부위(하지), 종양의 두께(Clark's stage IV이상), 주위 림프절 전이가 있는 경우에 나쁜 예후를 보였으나, 다른 연구와는 다르게 발병 연령은 예후에 큰 영향을 미치지 않는 것으로 조사되었다. Purpose: To evaluate treatment outcomes of malignant melanoma and to analyze the factors that contributes to outcomes. Materials and Methods: We reviewed the 51 cases of malignant melanoma from March, 1997 to March, 2004 and were followed up more than 5 years. Average age was 49.4. We compared 5-year survival rate for each age, gender, site of occurrence, depth of tumor, metastasis of regional lymph node and immuno-chemo therapy. Results: 5-year survival rate was 88.5% for the age group below 65, 88.0% for the age group 65 and above, 62.5% for male and 100% for female. 5-year survival rate for the site of occurrence showed 100% in upper extremities, and 80.0% in lower extremities and 100% in other sites. 5-year survival rate was 100% for the stage below Clark stage III and 79.3% for the stage above IV. In surgical resection, 5-year survival rate was 66.7% for lymph node metastasis group and 94.9% for non-lymph node metastasis group. Conclusion: The prognostic factors of malignant melanoma were gender, tumor site, depth of tumor (Clark's stage) and metastasis of regional lymph node. But, there was no relation between the age and the survival rate in our study.

Dr. Speech Science를 이용한 정상 및 후두질환 환자의 음향분석

이형석,태경,장경진,김경우,김경래,박철원,Lee, Hyung-Seok,Tae, Kyung,Jang, Kyung-Jin,Kim, Kyung-Woo,Kim, Kyung-Rae,Park, Chul-Won 대한후두음성언어의학회 1997 대한후두음성언어의학회지 Vol.8 No.2

Background : For example, aerodynamic study, vibratory study, acoustic study, neuro-muscular test and psychoacoustic evaluation, a number of objective methods are now available for assessing pathologic voice change. They help to differentiate pathologic condition from normal condition and to monitor pathologic and aging change. These laboratory analyses are used commonly to monitor speech therapy and to follow a patient's recovery after surgery. Objectives : We investigated the values of jitter, shimmer and NNE of normal person and hoarseness patients in Korea. The values of Jitter and shimmer might be meaningful parameters distinguishing pathologic vibration from normal and recovery after surgery. Materials and Methods : Statistical significance between normal control and 48 subjects taken microlaryngeal surgery were compared with Dr. speech science program that is computerized system for acoustic analysis of voice production employed to determine vocal characteristics of pitch perturbation(jitter) and amplitude perturbation(shimmer). Results : The mean normal values of jitter and shimmer were 0.226${\pm}$0.110(%), 2.200${\pm}$0.421(%) in male and 0.164${\pm}$0.060(%), 2.063 ${\pm}$0.575(%) in female. In patients with vocal nodule, the preoperative and postoperative values of jitter and shimmer were valueless. In patients with vocal polyps, the preoperative and postoperative values of jitter and shimmer were valuable. Conclusion : Dr. speech science program was effective to monitor laryngeal disease and aging changes.