• 제목/요약/키워드: Partial defect

검색결과 446건 처리시간 0.031초

SF6 가스중의 공진주파수에 따른 신호특성 (Characteristic as a Resonance Frequency of $SF_6$ Gas)

  • 이용희;이현동;박정남;신양섭;박장수;서정민
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 C
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    • pp.1867-1869
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    • 2003
  • In this paper, chamber(Circuit breaker compartment of C-GIS) made of stainless steel with 4 mm width is used. Artificial defect was made on enclosure or HV conductor of chamber and $SF_6$ gas was injected into it according to pressure. In this experiment, Acoustic emission sensors of different types was used to compare sensitivity to detect acoustic signal occurred by Partial discharge(PD) of according to types and resonance frequency in $SF_6$ gas atmosphere. Sensors used in tests was R6I, R15I and 2/4/6 Pre-Amplifier connected with R6IU without pre. amp. In case of R6IU, gain was adjusted with 40 dB like other sensors and operated by differential mode. Post amplifier(post. amp) and band pass filter(BPF) were developed Gain of post. amp. is 60 dB and BPF has band width of $50{\sim}300$ kHz. Also, envelope circuit developed reduces frequency of AE sensor. As a result, in $SF_6$ atmosphere, R6IU and R6I had resonance frequency of 60 Hz was better than R15I. Also, R6IU was better than R6I because of type property of pre.amp. had differential mode.

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역혈류성 전외측대퇴섬피판을 이용한 무릎 잘린끝의 재건 (Reconstruction of Disarticulated Knee Stump by Using Distally Based Anterolateral Thigh Island Flap)

  • 김형진;변재경;범진식;김양우
    • Archives of Plastic Surgery
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    • 제34권4호
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    • pp.485-489
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    • 2007
  • Purpose: The basic vascular anatomy and versatility of the anterolateral thigh flap was reported firstly by Song in 1984 and then by Zhang who introduced the reverse flow pattern of this flap. In this case, the authors reviewed various articles and their experiences with the distally based anterolateral thigh flap and applied it for coverage of bone-exposed wound occurred at the distal of the disarticulated knee stump. We consequently reported the reliability and resourcefulness of this flap in the difficult and limited situation. Methods: A 67-year-old-man who had suffered from arteriosclerotic obliterans inevitably underwent the disarticulation at knee joint due to clinical deterioration. He presented to our clinic with soft tissue necrosis and bone exposure at the stump. We debrided the wound and conducted the distally based anterolateral thigh island flap by transecting proximal portion of descending branch of the lateral circumflex femoral artery and the $14{\times}10cm$ sized flap was transferred to cover the defect. The pedicle measured 14 cm in length with pivot point 7 cm above the patella. Results: The postoperative course was mainly uneventful except early venous congestion for 4 days and subsequent partial skin loss. The wound was healed by secondary intension and no other sequelae had been observed during follow-up period of 12 months. Conclusion: Despite the presence of various reconstructive choices, the distally based anterolateral thigh island flap can be designed to repair soft tissue defects around the knee region, providing its reliable blood supply and long pedicle length, especially in the challenging cases.

Modified toe pulp fillet flap coverage: Better wound healing and satisfactory length preservation

  • Baek, Sang Oon;Suh, Hyo Wan;Lee, Jun Yong
    • Archives of Plastic Surgery
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    • 제45권1호
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    • pp.62-68
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    • 2018
  • Background Amputation is commonly performed for toe necrosis secondary to peripheral vascular diseases, such as diabetes mellitus. When amputating a necrotic toe, preservation of the bony structure is important for preventing the collapse of adjacent digits into the amputated space. However, in the popular terminal Syme's amputation technique, partial amputation of the distal phalanx could cause increased tension on the wound margin. Herein, we introduce a new way to resect sufficient bony structure while maintaining the normal length, based on a morphological analysis of the toes. Methods Unlike the pulp of the finger in the distal phalanx, the toe has abundant teardrop-shaped pulp tissue. The ratio of the vertical length to the longitudinal length in the distal phalanx was compared between the toes and fingers. Amputation was performed at the proximal interphalangeal joint level. Then, a mobilizable pulp flap was rotated $90^{\circ}$ cephalad to replace the distal soft tissue defect. This modified toe fillet flap was performed in 5 patients. Results The toe pulp was found to have a vertically oriented morphology compared to that of the fingers, enabling length preservation through cephalad rotation. All defects were successfully covered without marginal ischemia. Conclusions While conventional toe fillet flap coverage focuses on the principle of length preservation as the first priority, our modified method takes both wound healing and length into account. The fattiest part of the pulp is advanced to the toe tip, providing a cushioning effect and enough length to substitute for phalangeal bone loss. Our modified method led to satisfactory functional and aesthetic outcomes.

광범위한 안면외상 환자에서의 미세술기를 이용한 재건술 (Microsurgical reconstruction of posttraumatic large soft tissue defects on face)

  • 백우열;송승용;노태석;이원재
    • 대한의사협회지
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    • 제61권12호
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    • pp.724-731
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    • 2018
  • Our faces can express a remarkable range of subtle emotions and silent messages. Because the face is so essential for complex social interactions that are part of our everyday lives, aesthetic repair and restoration of function are an important tasks that we must not take lightly. Soft-tissue defects occur in trauma patients and require thorough evaluation, planning, and surgical treatment to achieve optimal functional and aesthetic outcomes, while minimizing the risk of complications. Recognizing the full nature of the injury and developing a logical treatment plan help determine whether there will be future aesthetic or functional deformities. Proper classification of the wound enables appropriate treatment, and helps predict the postoperative appearance and function. Comprehensive care of trauma patients requires a diverse breadth of skills, beginning with an initial evaluation, followed by resuscitation. Traditionally, facial defects have been managed with closure or grafting, and prosthetic obturators. Sometimes, however, large defects cannot be closed using simple methods. Such cases, which involve exposure of critical structures, bone, joint spaces, and neurovascular structures, requires more complex treatment. We reviewed and classified causes of significant trauma resulting in facial injuries that were reconstructed by microsurgical techniques without simple sutures or coverage with partial flaps. A local flap is a good choice for reconstruction, but large defects are hard to cover with a local flap alone. Early microsurgical reconstruction of a large facial defect is an excellent choice for aesthetic and functional outcomes.

Reconstruction of cutaneous defects of the nasal tip and alar by two different methods

  • Kim, Yong Hun;Yoon, Hyung Woo;Chung, Seum;Chung, Yoon Kyu
    • 대한두개안면성형외과학회지
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    • 제19권4호
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    • pp.260-263
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    • 2018
  • Background: The alar and nasal tip are important subunits of the nose. Determining the optimal procedure for reconstructing a cutaneous defect in a nasal subunit depends on several factors including size, location, and involvement of deep underlying structures. We treated cutaneous defects after tumor ablation in the alar and nasal tip with a local flap, using an S-shaped design and a modified V-Y advancement flap with a croissant shape. Methods: We analyzed 36 patients with skin tumors who underwent flap coverage after tumor ablation. Rotation flaps were used in 26 cases and croissant-shaped V-Y advancement flaps were used in 10 cases. The primary cause of the defects was skin cancer, except for one benign tumor. Results: The mean patient age was 71 years. The size of the defects ranged from $0.49cm^2$ to $3.5cm^2$. No recurrence of skin cancer was noted and all flaps lasted until the end of follow-up. Partial desquamation of the epidermis was noted in one case. The postoperative appearance for most patients was excellent, objectively and subjectively. Conclusion: For cutaneous defects of up to about $4.0cm^2$ of the alar and nasal tip, local flaps using our methods offered a good cosmetic and therapeutic result. The main advantage of our flaps is the minimal dissection required compared to bilobed and other local flap methods. We believe our flaps are a suitable option for alar and nasal tip reconstruction.

진동 특성을 이용한 접합된 차량 구조의 BSR(Buzz, Squeak, Rattle) 소음 강건성 관측에 대한 실험연구 (Experimental study to investigate the structural integrity of welded vehicle structure for BSR (Buzz, Squeak, Rattle) noise by vibration measurement)

  • 곽윤상;이종호;박준홍
    • 한국음향학회지
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    • 제38권3호
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    • pp.334-339
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    • 2019
  • 차량 점용접 부위에서 BSR(Buzz, Squeak, Rattle) 소음 발생 가능성을 국부 진동을 사용하여 비파괴적으로 추정하는 진동기반 계측법을 제시한다. 용접부에 부착된 구조물에 의한 점용점 부위의 국부적인 진동을 유발하고 진동전달 특성을 파악한다. 관측된 진동 특성으로부터 국부 구조의 굽힘강성값을 도출하였다. 강성값의 변화로부터 점용접의 상태 강건성을 파악하였다. 제시되는 방법의 검증을 위해 부분적으로 용접품질이 변화된 시편을 제작하였다. 제작된 시편에서 계측된 진동 특성을 분석하였다. 용접 강건성에 의해 변화하는 특정 주파수 대역을 파악하였다. 구조별, 위치별 계측을 통해 제시된 방법으로 분별이 가능한지 검증하였다. 국부 진동 평가방법은 구조물의 용접 강건성을 생산 현장에서 파악하게 하는 평가방법으로써 BSR발생 가능성을 저감하기위한 생산 품질 확보에 사용될 수 있다.

언더컷 형상의 판재 성형품에 보강용 CFRP 패치의 접합을 위한 공정기술 개발 (Development of a process to apply uniform pressure to bond CFRP patches to the inner surface of undercut-shaped sheet metal parts)

  • 이환주;전용준;조훈;김동언
    • Design & Manufacturing
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    • 제14권4호
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    • pp.65-70
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    • 2020
  • Partial reinforcement of sheet metal parts with CFRP patch is a technology that can realize ultra-lightweight body parts while overcoming the high material cost of carbon fiber. Performing these patchworks with highly productive press equipment solves another issue of CFRP: high process costs. The A-pillar is the main body part and has an undercut shape for fastening with other parts such as roof panels and doors. Therefore, it is difficult to bond CFRP patches to the A-pillar with a general press forming tool. In this paper, a flexible system that applies uniform pressure to complex shapes using ceramic particles and silicone rubber is proposed. By benchmarking various A-pillars, a reference model with an undercut shape was designed, and the system was configured to realize a uniform pressure distribution in the model. The ceramic spherical particles failed to realize the uniform distribution of high pressure due to their high hardness and point contact characteristics, which caused damage to the CFRP patch. Compression equipment made of silicone rubber was able to achieve the required pressure level for curing the epoxy. Non-adhesion defects between the metal and the CFRP patch were confirmed in the area where the bending deformation occurred. This defect could be eliminated by optimizing the process conditions suitable for the newly developed flexible system.

Effectiveness of porcine-derived xenograft with enamel matrix derivative for periodontal regenerative treatment of intrabony defects associated with a fixed dental prosthesis: a 2-year follow-up retrospective study

  • Kim, Yeon-Tae;Jeong, Seong-Nyum;Lee, Jae-Hong
    • Journal of Periodontal and Implant Science
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    • 제51권3호
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    • pp.179-188
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    • 2021
  • Purpose: Due to the difficulty of the hygienic care and sanitary management of abutment teeth and subpontic areas associated with fixed dental prostheses (FDPs), intrabony defects occur and accelerate due to the accumulation of plaque and calculus. This study aimed to evaluate the efficacy of regenerative periodontal surgery for intrabony defects associated with FDPs. Methods: The study inclusion criteria were met by 60 patients who underwent regenerative treatment between 2016 and 2018, involving a total of 82 intrabony defects associated with FDPs. Periodontal osseous lesions were classified as 1-, 2-, and 3-wall intrabony defects and were treated with an enamel matrix derivative in combination with bone graft material. The changes in clinical (pocket probing depth [PPD] and clinical attachment level [CAL]) and radiographic (defect depth and width) outcomes were measured at baseline and at 6, 12, and 24 months. Results: Six months after regenerative treatment, a significant reduction was observed in the PPD of 1-wall (P<0.001), 2-wall (P<0.001), and 3-wall (P<0.001) defects, as well as a significant reduction in the CAL of 2-wall (P<0.001) and 3-wall (P<0.001) intrabony defects. However, there was a significant increase in the CAL of 1-wall intrabony defects (P=0.003). Radiographically, a significant reduction in the depth of the 3-wall (P<0.001) defects and a significant reduction in the width of 2-wall (P=0.008) and 3-wall (P<0.001) defects were observed. The depth decreased in 1-wall defects; however, this change was not statistically significant (P=0.066). Conclusions: Within the limitations of the current study, regenerative treatment of 2- and 3-wall intrabony defects associated with FDPs improved clinical and radiological outcomes. Additional prospective studies are necessary to confirm our findings and to assess long-term outcomes.

심한 결손부의 단계적 골증대술을 통한 임플란트 지지 고정성 보철 수복 증례 보고 (Implant-supported fixed prosthesis in patient with severe defects using staged GBR via 2-step augmentations: A case report)

  • 오세은;전지훈;박영범
    • 대한치과보철학회지
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    • 제60권4호
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    • pp.382-394
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    • 2022
  • 심한 치주염을 가진 환자의 치료는 환자의 개개 치아의 정확한 진단과 전략적인 치료 계획을 통해 단계적으로 진행되어야 한다. 임플란트 지지 고정성 보철 수복은 국소의치에 비해 환자의 만족도가 높고, 안정적인 수직 고경을 유지할 수 있는 장점이 있지만, 경조직이 부족한 다수 치아 결손 부위에서는 심미적인 측면의 실패와 치료 기간이 길어진다는 점의 단점이 있을 수 있다. 또한 통상의 고정성 보철물을 제작하고 장착하는 데에는 일정 기간이 소요되는데, 이 기간 동안 임시 보철물은 치아의 기계적, 생물학적, 심미적 요구 조건을 만족시켜야 한다. 이번 증례 보고에서는 상악과 하악의 부분 무치악 환자에서 단계적인 접근을 통한 임플란트 고정성 보철물을 수복한 증례를 보고하고자 한다.

몰드변압기의 보이드 결함 크기 판별 (Identification of Void Diameters for Cast-Resin Transformers)

  • 정기우;김성욱
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2022년도 추계학술대회
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    • pp.570-573
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    • 2022
  • 본 논문에서는 신경망 모델을 적용한 몰드변압기의 보이드 결함 크기 판별에 관한 연구를 수행하였다. PCB 기반의 로고우스키 코일형 부분방전 센서를 제작하여 부분방전 신호를 측정하였고, 보이드에 의한 부분방전 결함을 모의하기 위한 PD 전극계를 제작하였다. 또한 보이드는 원통형 모양의 알루미늄 틀을 제작하여 에폭시가 경화되는 과정에서 실린지를 삽입하고 공기를 주입하여 서로다른 직경을 가지는 4개의 시편을 제작하였다. 보이드 결함 크기 판별을 위해 부분방전 전하량, 방전 펄스 수, 위상 분포의 부분방전 특성 파라미터를 추출하여 Labview 기반의 VI (Virtual Instrument)로 역전파 알고리즘을 설계하였다. 실험 결과로부터 제작된 알고리즘은 90%이상의 판별률로 결함의 직경크기를 구분할 수 있었다. 본 연구의 결과는 현장에서 PD 측정 시 몰드변압기의 유지보수 및 절연물 교체의 근거 자료로 활용될 수 있을 것으로 판단된다.

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