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Analysis of the IGBT with improved trade-off characteristic between conduction and turn-off losses
Samuell Shin,Jongil Won,Kuidong Kim,Jongki Kwon,Yongseo Koo 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
In this paper, we tried different two approach to improve the performance of the IGBT. The first approach is that adding N+ region beside P-base in the conventional IGBT. It can make the conventional IGBT to get faster turn-off time and lower conduction loss. The second approach is that adding P+ region on right side under gate to improve latching current of conventional IGBT. The device simulation results show improved on-state, latch-up and switching characteristics in each structure. The first one was presented lower voltage drop(3.08V) and faster turn-off time(3.4us) than that of conventional one(3.66V/3.65us). Also, second structure has higher latching current(369A/㎠) that of conventional structure. Finally, we present a novel IGBT combined the first approach with second one for improved trade-off characteristic between conduction and turn-off losses. The proposed device has better performance than conventional IGBT.
새로운 구조의 nMOS 삽입형 IGBT의 전기적 특성 분석
신사무엘(Shin, Samuell),손정만(Son, Jung-Man),박태룡(Park, Tea-Ryoung),구용서(Koo, Yong-Seo) 한국전기전자학회 2008 전기전자학회논문지 Vol.12 No.4
본 논문에서는 기존 IGBT의 구조적 한계로 인한 순방향 전압강하와 스위칭 손실간의 트레이드-오프 관계를 극복하고, 좀 더 우수한 전기적 특성을 갖는 새로운 구조의 nMOS 삽입형 IGBT를 제안하였다. 제안된 구조는 IGBT소자의 셀(Cell)과 셀 사이에 존재하는 폴리(poly) 게이트 영역에 nMOS를 형성시킨 구조로 N-드리프트 층으로의 전자, 정공의 주입효율을 증가시켜 기존 구조보다 더 낮은 온-저항과 빠른 스위칭 손실을 얻도록 설계된 구조이다. 시뮬레이션 결과 제안된 구조의 단일 소자인 경우 순방향 전압강하와 스위칭 특성은 각각 2.65V와 4.5us로, 기존 구조가 갖는 3.33V와 5us비해 약 26%의 감소된 순방향 전압강하와 10%의 낮은 스위칭 특성을 보였으며 래치-업 특성은 773A/로 기존 520A/보다 33%의 상승된 특성을 보였다. In this paper, we proposed the novel IGBT with an additional n-type MOS structure to achieve the improved trade-off between turn-off and on-state voltage drop(Vce(sat)). These low on-resistance and the fast switching characteristics of the proposed IGBT are caused by an enhanced electron current injection efficiency which is caused by additional n-type MOS structure. In the simulation result, the proposed IGBT has the lower on state voltage of 2.65V and the shorter turn-off time of 4.5us than those of the conventional IGBT(3.33V, 5us).
신사무엘(Samuell Shin),손정만(Jungman Son),구용서(Yongseo Koo) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.11
This study is presented about electrical characteristics of 2500V planar gate IGBT The breakdown voltage and saturation voltage (Vce, sat) according to variations of gate length, emitter window region, and drift region depth were simulated using 2D simulator (MEDICI). In simulation results, when the gate length was 15㎛, the emitter window region was 8㎛ and drift region depth was 375㎛, the breakdown voltage and saturation voltage (Vce, sat) of optimized IGBT were simulated to 2810V, 3.4V respectively.
Metastasis of renal cell carcinoma around suture anchor implants
Samuel Baek,Myung Ho Shin,Tae Min Kim,Kyung-Soo Oh,Dong Ryun Lee,Seok Won Chung 대한견주관절의학회 2021 대한견주관절의학회지 Vol.24 No.2
We present an unusual case of bone metastases from renal cell carcinoma around orthopedic implants in a 78-year-old female with osteolytic, expansile, highly vascularized, malignant infiltration around suture anchors in the proximal humerus. The patient had undergone arthroscopic rotator cuff repair using suture anchor implants 6 years previously. After diagnosis of bone metastasis, she was successfully treated with metastasectomy and internal fixation using a plate and screws, with cement augmentation. This report is the first to document metastases around a suture anchor in a bone and suggests the vulnerability of suture anchor implants to tumor metastasis.
Shin Yen Tan,Meng Yew Tee,Moses Samuel 아시아영어교육학회 2017 The Journal of Asia TEFL Vol.14 No.4
This video study examines teachers’ questioning practices in English language classrooms in Malaysia, and how different types of questions, wait time, and reaction moves influence classroom interaction. The study found that although there was an overarching monologicality across all classrooms, teachers’ questioning practices were not limited to the typical, monologic mixture of display questions, non-existent or short wait time, and/or reaction moves which could obstruct student talk. There were also opportunities for dialogicality initiated through teachers’ employment of referential questions, longer wait time, and/or reaction moves which could facilitate advanced student talk, but monologicality in classroom interaction persisted. Such observation directs our attention to the understanding and further contemplation that nurturing dialogicality is not a mere issue of strategy use.
Shin, Woonsup,Zhu, Enhua,Nagarale, Rajaram Krishna,Kim, Chang Hwan,Lee, Jong Myung,Shin, Samuel Jaeho,Heller, Adam American Chemical Society 2011 ANALYTICAL CHEMISTRY - Vol.83 No.12
<P>When a current or a voltage is applied across the ceramic membrane of the nongassing Ag/Ag<SUB>2</SUB>O-SiO<SUB>2</SUB>-Ag/Ag<SUB>2</SUB>O pump, protons produced in the anodic reaction 2Ag(s) + H<SUB>2</SUB>O → Ag<SUB>2</SUB>O(s) + 2H<SUP>+</SUP> + 2e<SUP>–</SUP> are driven to the cathode, where they are consumed by the reaction Ag<SUB>2</SUB>O(s) + H<SUB>2</SUB>O + 2e<SUP>–</SUP> → 2Ag(s) + 2 OH<SUP>–</SUP>. The flow of water is induced by momentum transfer from the electric field-driven proton-sheet at the surface of the ceramic membrane. About 10<SUP>4</SUP> water molecules flowed per reacted electron. Because dissolved ions decrease the field at the membrane surface, the flow decreases upon increasing the ionic strength. For this reason Ag<SUP>+</SUP> ions introduced through the anodic reaction and by dissolution of Ag<SUB>2</SUB>O decrease the flow. Their accumulation is reduced by applying Nafion-films to the electrodes. The 20 μL min<SUP>–1</SUP> flow rate of 6 mm i.d. pumps with Nafion coated electrodes operate daily for 5 min at 1 V for 1 month, for 70 h when the pump is pulsed for 30 s every 30 min, and for 2 h when operating continuously.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2011/ancham.2011.83.issue-12/ac201118t/production/images/medium/ac-2011-01118t_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac201118t'>ACS Electronic Supporting Info</A></P>
Samuel Baek,Tae Min Kim,Myung Ho Shin,Kyung-Soo Oh,Seok Won Chung 대한견주관절의학회 2021 대한견주관절학회 학술대회논문집 Vol.2021 No.3
Introduction and Background To evaluate the loop and knot security of the tape-type suture compared with the conventional cord-like suture using various arthroscopic knot techniques. Material and Method The biomechanical characteristics of the tape-type suture (2.0mm braided UHMWPE suture) and the conventional suture (no. 2 braided UHMWPE suture) were compared using 4 different knot types [2 sliding knots (SMC and Tennessee) and 2 non-sliding knots (Surgeon’s and Square)) with 2- and 3- half hitches with alternating posts each (total 16 senarios) in a closed-loop system on a material testing device. Each configurations were tested 12 times each, for loop security (maximum load applied between 0 and 3mm of displacement (N)) and for knot security (ultimate failure load (N) and mode of failure (suture breakage or knot slippage) at a strain rate of 1mm/second with a 5N preload. Results The 3 half-hitches showed significantly higher loop- and knot securities than 2 half-hitches in all suture and knot types (all p<0.05). In the 2 half-hitches, the tape-type suture showed significantly better loop security in the SMC (110.30±42.29N vs 75.82±21.20N, p=0.019) and Tennessee knots (123.51±24.96N vs. 85.22±37.29N, p=0.007), and higher ultimate failure load in the SMC (206.94±77.45N vs 150.68±53.79N, p=0.050) and Tennessee knots (212.49±51.28N vs 150.02±73.24N, p=0.024) compared with the conventional suture. However, in the 3 half-hitches, there were no differences in loop- and knot securities between suture types in every knot configurations (all p>0.05). The common failure mode was the knot slippage in the 2 half-hitches, on the other hand, the suture breakage in the 3 half-hitches. However, there was no difference in the failure mode between suture types, except the SMC knot with 3 half-hitches which showed higher suture breakage in the conventional suture (p=0.037) Conclusions In the nonsliding knots, the loop- or knot- securities were not affected by suture types (tape suture or conventional suture). However, in the sliding knots of the SMC and Tennessee knots, the tape-type suture was more biomechanically secure when backed up with 2 half-hitches. This difference was disappeared when backed up with 3 half-hitches.
Samuel Baek,Geum-Ho Lee,Myung Ho Shin,Tae Min Kim,Kyung-Soo Oh,Seok Won Chung 대한견주관절의학회 2023 대한견주관절의학회지 Vol.26 No.3
The authors present a case of transient postoperative inferior subluxation of the shoulder after arthroscopic surgical stabilization for recurrent anterior dislocation. The patient was a 61-year-old woman with myasthenia gravis (MG). The first anterior shoulder dislocation occurred because of a fall to the ground. Despite a successful closed reduction, two more dislocations occurred in 3 weeks. Magnetic resonance imaging revealed an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion, an engaging Hill-Sachs lesion, and large tears of the supraspinatus and infraspinatus tendons. The patient underwent arthroscopic rotator cuff repair and ALPSA repair with a remplissage procedure. Intraoperatively, no tendency for instability was found; however, a widened glenohumeral joint space and inferior subluxation of the humeral head without functional compromise was observed on the day after surgery and disappeared spontaneously on radiographs 2 weeks later. To the authors’ knowledge, this is the first report documenting the occurrence of transient postoperative inferior subluxation of the shoulder in a patient with MG.