단일 전력단 능동 클램프형 고주파 공진 인버터에 관한 연구

강진욱,박재욱,원재선,배영호,김동희 嶺南大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.30 No.2

This paper presents active-clamp type high frequency resonant inverter with single-stage. The proposed topology is an integrated circuit of active-clamp type high frequency resonant inverter with boost converters having the function of power factor correction. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. Hence a high power factor operation is achieved naturally. By adding active-clamp circuit to conventional class-E high frequency inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Theoretical analysis in converter part is performed with Psim 4.1 software tool and in inverter part is generally evaluated by using normalized parameter and characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter can be practically used as a power supply in the fields of induction heating applications, DC-DC converter, etc.

악성 갑상선 우연종의 임상상 및 초음파 소견의 진단적 가치

강한욱,김광원,이병완,강보현,김형훈,김범진,정재훈,민용기,이명식,이문규 대한내분비학회 2002 Endocrinology and metabolism Vol.17 No.5

연구배경: 최근 갑상선 초음파 검사의 빈번한 시행으로 갑상선 우연종의 발견이 증가하고 있다. 이러한 갑상선 우연종은 임상적으로 어떻게 접근하고 치료를 해야 하는지 적지 않은 문제가 되고 있다. 본 연구에서는 직경 1.5㎝ 이하의 갑상선 우연종의 유병률, 입상적 특징 및 초음파 특성, 그리고 가장 효율적인 진단적 접근에 대해 알아 봤다. 방법: 1999년 1월부터 2000년 12월까지 삼성서울병원 내과 및 일반외과로 갑상선 결절을 주소로 내원한 1457명을 대상으로 후향적 연구를 시행하였다. 우연히 발견된 직경 1.5㎝ 이하의 갑상선 결절을 가지는 환자들에서 갑상선 결절의 촉지 유무, 갑상선 기능검사, 항갑상선 항체, 갑상선 초음파 및 미세침 흡인세포검사, 99m^Tc 갑상선 스켄, 수술 조직검사 및 병기를 검토하였다. 결과: 분석한 갑상선 결절 1475예 중 갑상선 우연종의 유병률은 13.4%(198예)였다. 갑상선 우연종에서 악성률은 28.8%(57예)으로 나왔다. 양성 및 악성 갑상선 우연종에서 나이, 성별, 갑상선 기능검사, 결절 크기에는 의미 있는 차이는 없었다. 갑상선 스켄은 갑상선 우연종의 감별에 적합하지 않았다. 갑상선 결절의 초음파 지표 점수만이 양성 및 악석 갑상선 우연종의 감별에서 초음파 지표 점수의 민감도는 88.9%, 특이도는 74.4%, 양성 예측률은 92.4%로 나왔고 진단적 정환도는 85.5%였다. 갑상선암으로 수술을 받은 50명중 stage 1은 34명, stage 2는 6명, stage 3은 10명으로 대부분의 악성 갑상선 우연종은 낮은 TNM 병기로 나타났으나, 상당수에서는 국소 침범의 소견을 보였다. TNM 병기의 3기 환자 전부는 45세 이상이였고, 주로 갑상선암의 피막 침범에 의한 것이었다. 임파절 전이는 6명의 환자에서 나왔다. 결론: 악성 갑상선 우연종은 비교적 흔히 접할 수 있는 질환이며 양성 우연종과는 임상적으로 구별이 안 된다. 악성 갑상선 우연종은 발견 당시 대부분 낮은 병기이나, 갑상선의 피막 침범 및 임파절 전이가 상당수에서 발견되었다. 갑상선 우연종의 초음파 소견은 향후의 진단 방향을 제시하는 중요한 길잡이가 될 수 있다. 초음파 지표 점수 2점 이상의 갑상선 우연종에서만 초음파 유도 미세침 흡입검사를 권장한다. Background: High-resolution ultrasonography has made the detection of asymptomatic small thyroid possible. Recent increases in the detection of incidentalomas have created a clinical dilemma on how to properly manage such incidental nodules. We investigated the prevalence, clinical and ultrasonographic characteristics, and optimal diagnostic approach toward incidentally detected benign and malignant thyroid nodules of less than 1.5㎝ in size. Methods: A retrospective review was undertaken on the 1,475 patients who had visited Samsung Medical Center, Seoul Korea between January 1999 and December 2000. The review consisted of a physical examination of the thyroid gland, thyroid function test, antithyroid antibodies, thyroid ultrasonography, fine-needle aspiration biopsy, pathology and TNA staging of the incidentally detected thyroid nodules of less than 1.5㎝ in size. Results: The prevalence of thyroid incidentalomas was 13.4% and the malignancy rate within them was 28.8%. There were no significant differences in age, sex, thyroid function test and size between the benign and malignant incidentalomas. Ultrasonographic characteristics showed meaningful diagnostic value for the detection of malignancy in incidentalomas. Most malignant incidentalomas were of a low stage. Conclusion: Occult thyroid cancers are fairly common finding. There are no clinical difference between benign and malignant thyroid nodules less than 1.5㎝; however, ultrasonographic findings can be used to decision of optimal management strategies (J Kor Soc Endocrinol 17:649∼656, 2002).

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

내시경적 점막절제술로 치험한 식도 과립상 세포종 1례

강혁주,김성욱,최석진,이중현,장재식,서영범,윤병구,박건욱,김성자,김용섭,강승완,이구,양창헌,이창우,김욱년,이광헌,서정일 동국대학교 의학연구소 2000 東國醫學 Vol.7 No.-

과립상 세포종은 Schwann 세포 기원으로 생각되며 인체에 비교적 드물게 발생한다. 과립상 세포종은 전신 어느 곳에서나 발견될 수 있으나 주로 혀, 구강, 피부 혹은 유방 등에서 호발하며 드물게 위장관에서 발견된다. 위장관에서는 식도에서 가장 호발하며 다음으로 위, 대장 순이다. 과립상 세포종은 대부분, 특히 위장관에서는 양성이며 소수의 악성 병변이 보고되었다. 이러한 이유와 함께 수술 전의 진단이 어렵기 때문에 과립상 세포종에 대한 근본적인 치료는 현재까지 외과적 절제술이다. 최근에 시도되는 치료방법들로는 내시경적 레이저 치료, 용종절제술, 내시경적 점막 절제술 등이 있다. 저자들은 상부 소화관 내시경검사를 시행하여 식도 과립상 세포종을 진단하고 내시경적 점막 절제술을 시행하여 합병증 없이 퇴원하여 현재 재발없이 경과 관찰중인 1례를 경험하였기에 보고하는 바이다. Granular cell tumors, which occur infrequently, are probably of Schwann cell origin. They can occur almost anywhere in the body but usually affect the tongue, oral cavity, skin, or breasts and are rarely found in the gastrointestinal tracts. The esophagus is the most frequent gastrointestinal site, followed by the stomach and the colon. Granular cell tumors are generally benign, especially in the gastrointestinal tract, some malignant lesions have been reported. For this reason, and also because preoperative diagnosis is difficult, the standard treatment for granular cell tumor has until now been surgical excision. In recent years, other therapeutic methods is endoscopic laser therapy (ELT), polypectiomy, endoscopic mucosal resection (EMR). We report a case of esophageal granular cell tumor which was diagnosed by an endoscopy and managed using an endoscopic mucosal resection without complication.

전방 십자 인대 파열에서의 반월상 연골판 파열의 양상

강충남,김종오,김동욱,고영도,유재두,최창호 대한스포츠의학회 1999 대한스포츠의학회지 Vol.17 No.1

Injury to associated structures is expected to worsen the prognosis of ACL tears. Meniscal injuries are well known to coexist in knees with both acute and chronic ACL injuries. However, it is not conclusive whether the likelihood of encountering a repairable meniscal lesion diminishes as the time from injury increases. W e reviewed records of 127 patient receiving an arthroscopically assisted stabilizing procedure for an acute and chronic ACL injury incurred while skiing, soccer, traffic accident to associated meniscal injury. All patient had undergone arthroscopic evaluation. We classified acute injury as injury less than 3 months old at time of surgery, and chronic injury as more than 3 months old. Acute injuries were 88 cases and chronic injuries were 39 cases. In 55 ski-related injuries, 41 knees were acute and 14 knees were chronic. Fourteen(34%) meniscal tears were noted in chronic cases. In 42 soccer injuries, 20 knees were acute and 22 knees were chronic. In acute cases, 14(70%) meniscal tears were noted and in chronic cases, 14(64%) meniscal tears were noted. In 30 traffic accident injuries, 27 knees were acute and 3 knees were chronic. In acute cases, 19(70%) meniscal tears were noted and in chronic cases, 2(67%) meniscal tears were noted. There was strong trend of the increased incidence of medial involvement in the non-skiers than in the skiers, In the type of meniscal tear with acute ACL rupture, 33 of 52 meniscal were longitudinal tear, 6 were horizontal tear, 4 were radial tear(only in lateral meniscus) and 9 were complex tear. In the pattern of meniscal tear with chronic ACL rupture, 15 of 37 meniscal were longitudinal tear, 3 were horizontal tear, 1 was radial tear(only in lateral meniscus) and 18 were complex tear(medial meniscus 16, lateral meniscus 2). In the treatment of torn menisci, 29 of 52 meniscal tears were treated by conservative treatment and meniscal repair, 21 meniscal tears were treated by partial menisectomy and 2 meniscal tears were treated by subtotal menisectomy in acute injuries. In chronic injury, 10 of 37 meniscal tears were treated by conservative treatment and meniscal repair, 18 meniscal tears were treated by partial menisectomy and 9 meniscal tears were treated by subtotal menisectomy. There was no total menisectomy. As the time from injury increased, the medial meniscus tears were severe and were more likely to require menisectomy.

Quinlolone 유도체 국소도포에 의한 좌창치료의 임상적 연구

권철욱,노영석,김재홍,조소연,강형철,함정희 大韓臨床藥理學會 1994 臨床藥理學會誌 Vol.2 No.2

Sr·페라이트의 자기특성에 관한 연구

임재근,서강수,문현욱,신용진 明知大學校 産業技術硏究所 1992 産業技術硏究所論文集 Vol.11 No.-

This thesis is the study on the magnetic properties of strontium (Sr) ferrite. Specimens of SrO·nFe₂O₃,basic composition, with n=5.9 which is nonstoichiomatric composition region were prepared by sintering at 1275°C for 1hr, whthin air surroundings. In order to increase coercivity, additives of 0.4wt%SiO₂ and 0.7wt%CaCO₃ were added into basic composition, and 0.5wt%∼2.0wt%Cr₂O₃ was added as second additives. In case of second additives 1.5wt%Cr₂O₃, it was obtained uniformed grain size and magnetic properties was increased. The sintering temperature was 1150°C, 1180°C, 1210°C, 1240°C and 1270°C respectivily and cooling was performed in furnance. From the research and experiments on the magnetic properties of strontium (Sr) ferrite based on the complex additive technique, it was obtained good magnetic properties of (BH)mas=0.72MGOe, at the sintering temperature of 1210°C, in the case of (basic composition)+(basic additive)+(1.5wt%Cr₂O₃)

두개강내로 전이된 Adenoid Cystic Carcinoma 2례 : 증례보고 Report of Two Cases

송재욱,윤상민,이창훈,장지수,이승훈,조경자,강신광 대한신경외과학회 1996 Journal of Korean neurosurgical society Vol.25 No.10

The authors describe two cases of unusual intracranial metastatic adenoid cystic carcinomas. A 42-year-old woman had a right pariental epidural metastatic mass. presumed hematogenous. spread from a primary tumor in the parotid gland. In second case, a 32-year-old man had a intracranial metastatic adenoid cystic carcinoma mimicking calcified psammomatous meningioma on CT scans. We present these unusual cases with a review of relevant literature and a discussion of possible pathogenesis.

UV 센서를 위한 Spiroxazine LB 단분자막 특성에 대한 연구

최성욱,박은진,장지훈,김재호,강신원 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.