Hardware Implementation of GaN-HEMT Based ZVS DC–DC Converter Considering PCB Layout

김종수,김현빈,이병국,김종수 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

The gallium nitride high electron mobility transistors (GaN HEMT) are among the most promising power semiconductor devices. However, these transistors have a small gate voltage margin compared with conventional power devices. In this paper, the gate voltage of GaN HEMTs is mathematically analyzed when it is applied to a zero voltage switching (ZVS) phase-shift full bridge (PSFB) DC–DC converter. The analysis accounts for nonlinear capacitance characteristics under the ZVS switching condition, and a critical parasitic inductance are derived to restrict the gate voltage to a safety operation area. The optimal layout for bridge topologies and gate drivers is proposed, to satisfy the derived parasitic inductance limitation. A 500-W-power laboratory phase-shift full-bridge DC–DC converter is implemented to verify the proposed layout.

준원자층 적층 방법으로 형성된 2형 양자점의 광 발광 특성 연구

김종수,조현준,소모근,김종수,김영호,이상준,이승현,Christiana B. Honsberg,김희대 한국물리학회 2019 새물리 Vol.69 No.8

We have studied the optical properties of InAs/GaAsSb submonolayer quantum dots (SML-QDs) through excitation intensity (Iex) and temperature dependent photoluminescence (PL) experiments. The SML-QDs with type-I (T-1) and type-II (T-2) band structures were grown using a GaAsSb spacer with a Sb composition of 0% and 15.8%. At 13 K, the PL signals from the T-1 and the T-2 samples were observed at 1.42 eV and 1.37 eV, respectively, when the Iex was 8.7 mW/cm2. The PL signal of the T-1 sample is due to the recombination of electrons and holes in the InAs SML-QDs. The PL signal of the T-2 sample is due to the recombination of electrons (in the GaAs electron band) and holes (in the GaAsSb spacer hole band) by type-II band alignment formed between GaAs and GaAsSb. The full widths at half maxima (FWHMs) of the T-1 and the T-2 samples were 7.09 meV and 24.6 meV, respectively, because the T-2 sample has a lower uniformity than the T-1 sample. As the excitation intensity was increased, the PL signals of the T-1 and the T-2 samples shifted to lower energy because of the quantum-confined Stark effect. As a result of these temperature-dependent PL experiments, the activation energy of the T-1 sample was found to be 30 meV. InAs/GaAsSb submonolayer 양자점(SML-QD)의 광학적인 특성을 여기광 세기(Iex)와 온도에 따른광발광 (Photoluminescence; PL) 실험을 통하여 연구하였다. 본 연구에 사용된 시료는 간격자인 GaAsSb 층의 Sb조성을 0%와 15.8%로 조절하여 Type-I (T-1) 과 Type-II (T-2) 밴드 구조의 SML-QD를 성장하였다. 13 K에서 Iex 가 8.3 mW/cm2 일 때 T-1과 T-2 시료의 PL신호는 각각 1.419 eV와 1.368 eV 에서 관측되었다. T-1 시료에서 관측된 전이신호는 InAs SML-QD의 전자와 정공간의 재결합에 의한것이다. T-2시료에서 관측된 PL신호는 GaAs와 GaAsSb 사이에 형성된 type-II 밴드 정렬에 의하여GaAs 전도대의 전자와 GaAsSb 간격자의 가전자대의 정공간의 재결합에 의한 것이다. 두 신호의 반값온폭 (Full-width at half maximum; FWHM)은 각각 7.09 meV와 24.6 meV 이었으며, 이는 T-2시료가T-1시료보다 균일성이 낮기 때문으로 사료된다. 여기광의 세기가 증가할수록 T-1와 T-2시료의 PL신호는낮은 에너지 쪽으로 이동하였는데, 이는 구속된 운반자에 의한 양자 구속 스타크 효과(quantum-confined Stark effect) 에 의한 것으로 사료된다. 온도 의존성 PL 실험의 결과, T-1 시료의 SML-QD의 활성화에너지는 30 meV이었다.

김종수의 삶과 음악 증언

김종수 한국음악문헌학회 2018 음악문헌학 Vol.- No.9

한국의 독창적인 행정가치에 관한 고찰 -15세기 중국 명조 영향권의 조선왕조를 중심으로-

김종수,한인희 한중사회과학학회 2016 한중사회과학연구 Vol.14 No.3

15세기 조선왕조는 중국 명조 영향권 아래에서 사대주의정책을 취하는 것이었다. 태조 이성계는 즉위 이전부터 명조에 대한 친명책을 표방하였다. 3대 태조 이후부터는 국왕의 즉위에는 반드시 명조의 승인을 받아야 했고, 종속의 상징으로 명조의 연호를 사용하였다. 필요에 따라 사신을 명조에 보내어 형식적으로 정치적인 종속관계를 맺게 되었지만 직접적으로 정치의 간섭을 받지 않았다. 따라서 조선왕조는 명조의 종속이 아닌 독창적인 행정가치를 가지고 있었다. 이 논문에서 15세기 조선왕조의 정치주도세력의 가치와 그에 따른 행정가치의 내용을 탐색하고 행정현상과 행정가치와의 상관관계를 분석하였다. 여기에서 15세기 조선왕조의 행정가치를 탐색한 이유는 이 시기가 조선왕조의 창업과 수성의 시기로 행정의 가치가 조선왕조 전 시기에 걸쳐 영향을 미쳤기 때문이다. 그 결과 15세기 행정가치는 민본성, 합법성, 집권지향성과 분권지향성, 사대성과 자주성, 명분성과 실용성으로 집약할 수 있다. Joseon dynasty was taken to the worship of the powerful policy under the spheres of influence of the chinese Ming dynasty in the 15th century. However, the Joseon dynasty was formally entered into the political components dependencies for the Ming dynasty. Joseon dynasty did not have a direct political interference from the Ming dynasty. Thus the Joseon dynasty had a creative public administration value. In this paper, it explored the value of the leading political forces’s ideology and the contents of public administration value of the 15th century’s Joseon dynasty, analyzed the correlation between public administration symptoms and public administration value. Because public administration value of this period had an impact throughout the period of the Joseon dynasty. As a result, public administration value of the 15th century’s Joseon dynasty can be condensed into civil real nature, legality, centralized and decentralized directivity, the worship of the powerful and independence, justification and practicality

무북직기용 Beating Cam 기구의 최적설계에 관한 연구

김종수,신중호,Kim, Jong-Su,Sin, Jung-Ho 한국기계연구원 1992 硏究論文集 Vol.22 No.-

The beating motion of a high speed shuttleless loom is driven by cams. Two cams become one system and their shaft laid across each other. Moreover, the shape of the cams is very complex and requires high precision for successful weft insertion and good interlacing with warp yarn. The iterative contact method is developed for use in design and analysis of the driving mechanism of a disk type cam with oscillating roller follower. The optimum design is performed by utilizing a CAD program, DISKCAM. The 8th order polynomial is selected to interpolate the desired shape trajectory of the cam, the optimal shape of the cams is defined based on the demension of the follower. The kinematic motion of the beating cam mechanism is investigated. The phase angle is determined to achive harmonious cam motions

부름-버림-따름

김종수 대한기독교서회 2017 基督敎 思想 Vol.704 No.-

소아 세기관지염과 천식과는 관계가 있는가?

김종수 한국의학사 1987 診斷과治療 Vol.7 No.5

<올해의 무형유산도시 사업>의 성과와 발전방향

김종수 무형유산학회 2017 무형유산학 Vol.2 No.2

부인과 수술환자에서 정맥내 자가통증조절법의 기저 주입 유무에 따른 비교

김종수,김진태,이규탁,임영진,도상환 대한마취과학회 2000 Korean Journal of Anesthesiology Vol.38 No.4

Backgroand : Intravenous patient-confrolled analgesia (IV-FCA) is widely used because it is a simple, safe, and effective method for postoperative pain control. Conoversies exist over the use of a continuous basal infusion in IV-PCA regarding its effectiveness. We evaluated the analgesic efficacy and side effects of PCA with basal infusion after gynecologic surgery and compared these results with PCA alone. Method : Eighty women undergoing elective gynecologic surgery under general anesthesia were studied. These patients were randomly assigned to receive either PCA alone (group 1) or PCA with basal infusion (group 2). Analgesic consumption, visual analogue scale (VAS) pain score, and side effects were assessed at postoperative 6 hours and 24 hours. Results : In group 1, the amounts of analgesic used during the postoperative 6 hours and 24 hours were 15 ± 5 and 30 ± 13 ml, the median VAS pain score at postoperative 6 hours and 24 hours were 50 and 35 respectively. In group 2, the amounts of analgesic us during the postoperative 6 hours and 24 hours were 19 ± 7 and 43 ± 1 ml, the mediam VAS pain score at postopetative 6 hours and 24 hours were 50 and 38 respectively. The analgesic consumption during the postoperative 6 hours and 24 hours was significantly higher in group 2 than in group 1. There was no significant difference in median VAS pain score between the groups. There were no significant differences in incidence of side effects between groups. Conclusions : The use of a PCA with basal infusion appears to offer no clinical advantage over PCA alone. (Koream J Anesthesiol 2000; 38: 6S1~656)

Protective Effects of Houttuynia cordata Thunb. on Gentamicin-induced Oxidative Stress and Nephrotoxicity in Rats

김종수,강창근,이현경,한도윤,허정호,김충희,김의경 한국독성학회 2013 Toxicological Research Vol.29 No.1

Development of a therapy providing protection from, or reversing gentamicin-sulfate (GS)-induced oxidative stress and nephrotoxicity would be of great clinical significance. The present study was designed to investigate the protective effects of Houttuynia cordata Thunb. (HC) against gentamicin sulfate-induced renal damage in rats. Twenty-eight Sprague-Dawley rats were divided into 4 equal groups as follows: group 1, control; group 2, GS 100 mg/kg/d, intraperitoneal (i.p.) injection; group 3, GS 100 mg/kg/d, i.p. + HC 500 mg/kg/d, oral; and group 4, GS 100 mg/kg/d i.p. + HC 1000 mg/kg/d, oral administration). Treatments were administered once daily for 12 d. After 12 d, biochemical and histopathological analyses were conducted to evaluate oxidative stress and renal nephrotoxicity. Serum levels of creatinine, malondialdehyde (MDA), and blood urea nitrogen (BUN), together with renal levels of MDA, glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were quantified to evaluate antioxidant activity. Animals treated with GS alone showed a significant increase in serum levels of creatinine, BUN, and MDA, with decreased renal levels of GSH, SOD, and CAT. Treatment of rats with HC showed significant improvement in renal function, presumably as a result of decreased biochemical indices and oxidative stress parameters associated with GS-induced nephrotoxicity. Histopathological examination of the rat kidneys confirmed these observations. Therefore, the novel natural antioxidant HC may protect against GSinduced nephrotoxicity and oxidative stress in rats.