• Journal of Power Electronics
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• 제18권3호
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• pp.879-891
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• 2018

A bidirectional dc-dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc-dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc-dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.

• Archives of Reconstructive Microsurgery
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• 제8권2호
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• pp.149-153
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• 1999

Purpose : To investigate the complication of donor site in latissimus dorsi muscle flap. Materials and Methods : From April 1983 to March 1999, forty patients with latissimus dorsi muscle flap for reconstruction of extremity and with a follow-up period of more than 12 months were included. We analysed the complication, shoulder function, degree of shoulder muscle weakness, skin scar width after operation. Results After 1 year, skin scar widening in 12 cases(30%), limitation of shoulder motion in 9 cases(12.5%), muscle weakness in 14 cases(17.5%) were found. Conclusion. The rate of complication at donor site after latissimus dorsi flap operation is around 10%. To minimize the complication, avoiding axillary skin incision, minimal invasive harvesting by endoscopy, meticulous suturing of subcutaneous layer are needed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권3호
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• pp.204-210
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• 2000

This paper proposes a new reactive-power compensator composed of a soft-switching current-source inverter. The compensator consists of 3-Phase IGBT bridge, dc reactor, and a resonant circuit. The resonant circuit offers the IGBT bridge to have PWM operation with minimal switching losses. A theoretical analysis and computer simulation with Is-Spice were done to verify the operation of the proposed system. Also a acaled-model of the system was built and tested for verifying the feasibility of proposed system.

• Archives of Plastic Surgery
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• 제48권4호
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• pp.384-388
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• 2021

Adequate positioning of the hand is a critical step in hand fracture operative repair that can impact both the clinical outcome and the efficiency of the operation. In this paper, we introduce the use of a thermoplastic splint with an added thumb stabilizing component as a means to increase the surgeon's autonomy and to streamline the patient care pathway. The thermoplastic splint is custom fabricated preoperatively by the specialist hand therapist. The splint is used prior, during, and post operation with minimal modification. The thumb component assists maintaining the forearm in a stable pronated position whilst drilling and affixing metal work. This is demonstrated in the video of removal of metal work and open reduction and internal fixation of a metacarpal fracture.

• Clinics in Shoulder and Elbow
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• 제14권1호
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• pp.73-79
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• 2011

목적: 경도 및 중등도 주관절 관절염 환자에서 최소 침습적 척골-상완 관절 성형술의 임상적 유용성에 대하여 알아보고자 한다. 대상 및 방법: 2000년 1월에서 2008년 12월까지 척골 신경 증상이 없는 경도 및 중등도의 주관절 관절염 환자에서 최소 침습적 척골-상완 관절 성형술을 시행받은 환자 29예 중 1년 이상 추시가 가능하였던 24예를 대상으로 하였다. 남자 20예, 여자 4예였으며, 평균 연령은 53세 (31~69세)였고, 평균 수술 시간, 관절 운동 범위, 술 후 관절 운동 시작까지의 시간, 술 후 1년 추시에서 Mayo elbow performance score (MEPS)를 조사하였다. 결과: 술 후 평균 1.8일 (1~4일)째 수동적 및 능동적 관절 운동을 시작하였고, 평균 수술 시간은 38분 (25~55분)이었다. 관절 운동 범위는 술 전 평균 25~104도 (신전 0~70도, 굴곡 80~130도)에서 술 후 1년 추시 상 평균 14~133도 (신전 0~45도, 굴곡 90~150도)로 평균 40도 관절운동 범위가 향상되었으며, 술 후 관절 운동 시작까지의 시간은 평균 1.6일 (1~5일)이었다. 술후 1년 추시에서 MEPS는 우수 19예, 양호 5예이었다. 술 후 합병증으로 창상 치유지연 1예, 술후 부종 7예가 있었으나 자연적으로 호전되었다. 결론: 경도 및 중등도 주관절 관절염 환자에서 최소 침습적 척골-상완 관절 성형술은 수술 시간이 짧고 조기 관절 운동이 가능하며 통증이 적으므로 임상적으로 유용한 수술이다.

• 한국의학물리학회지:의학물리
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• 제27권3호
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• pp.169-174
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• 2016

The aim of this study is to investigate the delivery accuracy of intensity-modulated radiation therapy (IMRT) plans in the two-headed mode of the ViewRay$^{TM}$ system in comparison with that of the normal operation treatment plan of the machine. For this study, a total of eight IMRT plans and corresponding verification plans were generated (four head and neck, two liver, and two prostate IMRT plans). The delivered dose distributions were measured using ArcCHECK$^{TM}$ with the insertion of an ionization chamber. We measured the delivered dose distributions in three-headed mode (normal operation of the machine), two-headed mode with head 1 disabled, two-headed mode with head 2 disabled, and two-headed mode with head 3 disabled. Therefore, a total of four measurements were performed for each IMRT plan. The global gamma passing rates (3%/3 mm) in three-headed mode, head 1 disabled, head 2 disabled, and head 3 disabled were $99.9{\pm}0.1%$, $99.8{\pm}0.3%$, $99.6{\pm}0.7%$, and $99.7{\pm}0.4%$, respectively. The difference in the gamma passing rates of the three- and two-headed modes was insignificant. With 2%/2 mm, the rates were $96.6{\pm}3.6%$, $97.2{\pm}3.5%$, $95.7{\pm}6.2%$, and $95.5{\pm}4.3%$, respectively. Between three-headed mode and head 3 disabled, a statistically significant difference was observed with a p-value of 0.02; however, the difference was minimal (1.1%). The chamber readings showed differences of approximately 1% between three- and two-headed modes, which were minimal. Therefore, the treatment plan delivery in the two-headed mode of the ViewRay$^{TM}$ system seems accurate and robust.

• Archives of Plastic Surgery
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• 제34권2호
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• pp.197-202
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• 2007

Purpose: The gluteal artery perforator flaps earned its popularity in buttock reconstruction due to the lower morbidity of the donor site and the flexibility in the design. Speedy and safe reconstruction is important for the success of buttock reconstruction. If a proper design is selected, satisfactory results can be obtained with more simple method of surgery. Methods: Between April 2005 and April 2006, buttock reconstruction by using gluteal artery perforator flaps were performed on sacral sores(6 cases), ischial sores(2 cases) and malignant melanoma on buttock(1 case). Various designs depending on the location and the size of the defect was made. In those designs, perforator was used as an axis for the minimal dissection of the vessel. Donor site from which sufficient amount of soft tissue can be transferred was selected, and also not causing high tension against the recipient site during the donor site closure. In addition, postoperative aesthetics, and the possibility of another design of a second operation which can be necessary in the future, was considered. Results: Patient follow up was for a mean period of 10.8 months. All flaps survived except for one that had undergone partial necrosis. Wound dehiscence was observed in one patient treated by secondary closure. Most patients presented with cosmetically and functionally satisfying results Conclusion: By designing the flap using the perforator as an axis, depending on the defect size and degree, reconstruction can be performed with only a small tension to the donor and the recipient site. And the minimal perforator dissection allowed easier and faster reconstruction. Selection of a proper design is the key procedure which greatly affects operation time and result success.

• 대한족부족관절학회지
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• 제9권2호
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• pp.173-178
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• 2005

Propose: There have been many debates about the ideal surgical technique for acute Achilles tendon rupture. The purpose of this study is to review and analyze the clinical outcome of the acute Achilles tendon ruptures that had been repaired by indirect suture technique with minimal incision that utilized an instrument called Achillon (Newdeal, France). Materials and Methods: This study is based on the 14 cases (14 patients) of acute Achilles tendon total ruptures that have been repaired by minimal incision technique utilizing Achillon instrument from June 2003 to December 2004. Two cases were reruptured before 8 weeks and repaired again using Krackow suture which left 12 feet for postoperative functional evaluation with at least 6 months of follow-up. Ten cases were men and average age at time of injury was 34.4 (26-49) years. The time from injury to surgery was an average of 4.5 (1-9) days and the postoperative evaluations were done by an Arner-Lindholm scale and AOFAS score. The ability to return to original work and sports activities as well as patient satisfaction were also evaluated. Results: The follow-up period was averaged for 13.2 (6-24) months. Seventy-one percent of cases were ruptured during sports activities. The ruptured level was the average of 5.1 cm (3.2-8 cm) above calcaneal attachment and the skin incision was averaged for 2.7 cm (2.5-3.0 cm) long. At final follow-up, standing on tip-toe was possible in all cases while the heel-floor height on ruptured side was shorter by 0.7 cm (0-2 cm). By Arner-Lindholm evaluation scale, 9 cases were excellent, and 3 cases were good. Overall AOFAS score was an average of 96.1 (94-100), and all patients were satisfied with the result. Patients returned to work at an average of 1.3 months after the surgery and pre-injury sports activities were all possible from at 6 months after operation. Conclusion: Since we have treated acute Achilles tendon ruptures with minimal incision technique utilizing the Achillon and gained encouraging functional results with all patients returning to previous work with high patient satisfaction, this technique could be recommended as one of the ideal surgical options for the Achilles tendon ruptures.

• Archives of Plastic Surgery
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• 제44권3호
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• pp.210-216
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• 2017

Background In treating minor-form or microform cleft lip, obtaining an optimal result is a challenge because of the visible scarring caused by traditional surgery. We present a refined method using muscle overlapping with a minimal skin incision in patients younger than 3 years, a group characterized by thin muscle. Methods The surgical technique involves restoration of the notched vermillion using Z-plasty, formation of the philtral column using overlapping of an orbicularis oris muscle flap through an intraoral incision, and correction of the cleft lip nasal deformity using a reverse-U incision and V-Y plasty. A single radiologist evaluated ultrasonographic images of the upper lip. Results Sixty patients were treated between September 2008 and June 2014. The age at the time of operation ranged from 6 to 36 months (mean, 26 months). The follow-up period ranged from 8 to 38 months (mean, 20 months) in minor-form cases and from 14 to 64 months (mean, 37 months) in microform cases. A notched cupid's bow was corrected in 10 minor-form cases and 50 microform cases. Ultrasonographic images were obtained from 3 patients with minor-form cleft lip and 9 patients with microform cleft lip 12 months after surgery. The average muscle thickness was 4.5 mm on the affected side and 4.1 mm on the unaffected side. Conclusions The advantages of the proposed procedure include the creation of an anatomically natural philtrum with minimal scarring. This method also preserves the continuity and function of the muscle and provides sufficient augmentation of the philtral column and nostril sill.

• 한국안전학회지
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• 제36권4호
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• pp.12-19
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• 2021

This paper presents a safety assessment method for FTA-based induction heating systems; the failures and causes of electrical fire are first analyzed for each part and module qualitatively, and methods to manage high probabilities of failure and electrical fire are considered, thereby improving the reliability of the induction heating system. The cumulative importance value (ACC) of the minimal cut set is drawn by setting failure as the top event, and STACK and SMPS are observed to account for about 70% of the induction heating system failures. Thus, intensively managing the basic events contained in the minimal cut set of failures for STACK and SMPS is expected to provide effective and stable operation of the induction heating system. When electrical fire is set as the top event, the STACK percentage is 90%. Accordingly, the current IGBT is changed to a FET to increase the applied voltage and prevent induction heating system failure, and a heat sink plane is installed to prevent FET heating caused by switching, thereby preventing an electrical fire. By classifying the parts and modules of the induction heating system in detail and by applying FTA based on actual failure rates and relevant data, more practical and reasonable results may be expected. Hence, continuous research must be conducted to ensure safety when using induction heating systems.