• Corrosion Science and Technology
• /
• 제16권3호
• /
• pp.115-127
• /
• 2017

Coal tar-coated pipes buried in a domestic nuclear power plant have operated under the cathodic protection. This work conducted the simulation of the coating performance of these pipes using a FEM method. The pipes, being ductile cast iron have been suffered under considerably high cathodic protection condition beyond the appropriate condition. However, cathodic potential measured at the site revealed non-protected status. Converting from 3D CAD data of the power plant to appropriate type for a FEM simulation was conducted and cathodic potential under the applied voltage and current was calculated using primary and secondary current distribution and physical conditions. FEM simulation for coal tar-coated pipe without defects revealed over-protection condition if the pipes were well-coated. However, the simulation for coal tar-coated pipes with many defects predict that the coated pipes may be severely degraded. Therefore, for high risk pipes, direct examination and repair or renewal of pipes are strongly recommended.

• Journal of Korean Dental Science
• /
• 제7권1호
• /
• pp.38-42
• /
• 2014

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is defined as exposed necrotic bone without evidence of healing for at least 8 weeks in the maxillofacial area in a patient with history of bisphosphonate use. Obtaining complete coverage of the hard tissue by soft tissue in BRONJ patients is especially important. Therefore, managing the mucosa is one of the key factors in a successful outcome, but this is especially hard to achieve in BRONJ patients. Various applications of buccal fat pad in oral reconstruction-including the closure of surgical defects following tumor excision, repair of surgical defects following the excision of leukoplakia and submucous fibrosis, closure of primary and secondary palatal clefts, coverage of maxillary and mandibular bone grafts, and lining of sinus surface of maxillary sinus bone graft in sinus lift procedures for maxillary augmentation-have been studied. Eliminating all potential sites of infection and post-operative infection control is crucial in BRONJ. We present a case using the buccal fat pad pedicle for a stage 3 BRONJ defect. Uneventful total epithelialization of the buccal fat pad regardless of size was noted. In summary, the buccal fat pad has versatile application and various recipient sites for surgical utilization. It is an easy technique, with promising overall success rates. With careful selection and handling, buccal fat graft can resolve problems with soft tissue coverage in stage 2 or 3 BRONJ patients.

• Archives of Plastic Surgery
• /
• 제39권6호
• /
• pp.626-630
• /
• 2012

Background Recent literature has indicated that free flaps are currently considered the preferred choice for head and neck reconstruction. However, head and neck cancer patients are frequently treated with chemoradiotherapy, which is often associated with a poor general and local condition, and thus, such patients are ineligible for free flap reconstruction. Therefore, other reconstruction modalities should be considered. Methods We used lower trapezius musculocutaneous (LTMC) flap based on the dorsal scapular artery to reconstruct head and neck defects that arose from head and neck cancer in 8 patients. All of the patients had undergone preoperative chemoradiotherapy. Results There were no complications except one case of partial flap necrosis; it was treated with secondary intention. Healing in the remaining patients was uneventful without hematoma, seroma, or infection. The donor sites were closed primarily. Conclusions The LTMC flap is the preferred flap for a simple, reliable, large flap with a wide arc of rotation and minor donor-site morbidity. The authors recommend this versatile island flap as an alternative to microvascular free tissue transfer for the reconstruction of defects in the head and neck region, for patients that have undergone preoperative chemoradiotherapy.

• 대한두개안면성형외과학회지
• /
• 제21권5호
• /
• pp.269-275
• /
• 2020

Background: The advance in microsurgical technique has facilitated a proper approach for reconstruction of extensive head and neck defects. For the success of free tissue reconstruction, selection of the recipient vessel is one of the most important factors. However, the vascular anatomy of this region is very complex, and a clear guideline about this subject is still lacking. In this study, we present our 30 years of experiences of free tissue reconstruction for head and neck defects. Methods: In this retrospective study, we analyzed a total of 138 flaps in 127 patients who underwent head and neck reconstruction using free tissue transfer following tumor resection between October 1986 to August 2019. Patients who underwent facial palsy reconstruction were excluded. Medical records including patient's demographics, detailed operation notes, follow-up records, and photographs were collected and analyzed. Results: Among a total of 127 patients, 10 patients underwent a secondary operation due to cancer recurrence. The most commonly used type of flap was radial forearm flap (n=107), followed by the anterolateral thigh flap (n=18) and fibula flap (n=10). With regard to recipient vessels, superior thyroid artery was most commonly used in arterial anastomosis (58.7%), and internal jugular vein (51.3%) was the first choice for venous anastomosis. The flap survival rate was 100%. Four cases of venous thrombosis were resolved with thrombectomy and re-anastomosis. Conclusion: Superior thyroid artery and internal jugular vein were reliable choices as recipient vessels. Proper recipient vessel selection could improve the result of head and neck reconstruction.

• Archives of Reconstructive Microsurgery
• /
• 제24권1호
• /
• pp.7-12
• /
• 2015

Purpose: The rectus abdominis musculocutaneous (RAM) flap has contributed to the efficient reconstruction of soft tissue defects. The flap has the advantage of easy dissection, minimal donor site morbidity, and the constant vascular anatomy with long pedicle. Authors used the free RAM flap to reconstruct multi-located soft tissue defects while still considering functionality and aesthetics. We present the long-term outcomes and versatility of free RAM flaps. Materials and Methods: From 1994 to 2004, all patients who underwent soft tissue reconstruction with free RAM flap were reviewed retrospectively. The site of the reconstruction, vessels of anastomosis, type of RAM flap, and outcomes, including flap success rate, hospital stay after flap transfer, conduction of secondary procedure, flap complications, and donor-site complications were analyzed. Results: Twenty-one patients underwent 24 free RAM flaps in site of breast, face, upper extremity and lower extremity. Mean follow-up period was 36.1 months (range, 3~156 months). The overall success rate was 92% with only a loss of 2 flaps. Minor complications related to transferred flaps were necrosis of 2 partial flaps, hematoma formation in 3 cases, and a wound infection in 1 case. Donor site morbidity was not observed. Debulking surgery was performed in 4 patients, and scar revision was performed in 3 patients. Conclusion: Free RAM flap is a workhorse flap for general soft-tissue reconstruction with minimal donor site morbidity with aesthetically good results. Thus, the free RAM flaps are versatile, and sturdy for any sites of soft-tissue where reconstruction could be performed.

• Journal of Electrochemical Science and Technology
• /
• 제7권4호
• /
• pp.306-315
• /
• 2016

Amorphous vanadium titanates (aVTOs) are examined for use as a negative electrode in lithium-ion batteries. These amorphous mixed oxides are synthesized in nanosized particles (<100 nm) and flocculated to form secondary particles. The $V^{5+}$ ions in aVTO are found to occupy tetrahedral sites, whereas the $Ti^{4+}$ ions show fivefold coordination. Both are uniformly dispersed at the atomic scale in the amorphous oxide matrix, which has abundant structural defects. The first reversible capacity of an aVTO electrode ($295mAhg^{-1}$) is larger than that observed for a physically mixed electrode (1:2 $aV_2O_5$ | $aTiO_2$, $245mAhg^{-1}$). The discrepancy seems to be due to the unique four-coordinated $V^{5+}$ ions in aVTO, which either are more electron-accepting or generate more structural defects that serve as $Li^+$ storage sites. Coin-type Li/aVTO cells show a large irreversible capacity in the first cycle. When they are prepared under nitrogen (aVTO-N), the population of surface hydroxyl groups is greatly reduced. These groups irreversibly produce highly resistive inorganic compounds (LiOH and $Li_2O$), leading to increased irreversible capacity and electrode resistance. As a result, the material prepared under nitrogen shows higher Coulombic efficiency and rate capability.

• 마이크로전자및패키징학회지
• /
• 제16권3호
• /
• pp.61-65
• /
• 2009

단결정 실리콘 웨이퍼 위에 그라인딩 공정을 사용하여 인위적으로 결정학적 결함을 만들고 선택적 습식 식각 공정을 통하여 반사율을 저감시켜 태양전지에 적용할 수 있는 새로운 표면 조직을 형성하였다. 식각 용액의 농도와 식각 시간에 따른 표면 형태의 변화를 분석하고 그에 따른 표면의 광학적 반사율의 변화를 측정하였다. 결정학적 결함 분석과 표면 형태의 관찰은 각각 투과전자 현미경과 주사전자현미경을 이용하였고 광학적 특성은 spectrophotometer를 이용하여 분석하였다. 상기 방법에 의한 최적화된 실리콘 표면의 반사율은 평균 1%이하의 우수한 결과를 보였으며 짧은 공정시간 및 가격효율성 면에서 효과적인 제조 방법이라고 사료된다.

• 정보관리연구
• /
• 제39권2호
• /
• pp.95-130
• /
• 2008

본고는 전자기록 환경에서의 국가 평가체계 정비 방향을 모색하기 위한 시론적 연구로서의 의미를 지닌다. 전자기록 환경에서의 필연적인 평가방식이라 할 수 있는 기능평가는 국가적 차원의 영구보존 기록 선별에는 일정 한계를 지닌다. 이에 본고에서는 우선 기능평가가 지닌 한계를 논의한 다음, 이를 보완하기 위한 방안으로 영구보존 대상 평가전략의 필요성을 제기하였다. 그리고 이에 대한 구체적인 사례를 고찰하기 위해, 호주의 범정부 기능분석, 영구의 평가정책 및 수집정책, 독일의 다기관협력 평가전략, 캐나다의 거시평가 전략을 분석하였다. 결국 이러한 분석은 현용 가치와 사회적 가치가 조화된 국가 평가체계의 토대를 제공해주게 된다.

• Archives of Plastic Surgery
• /
• 제36권5호
• /
• pp.571-577
• /
• 2009

Purpose: The Provision of thin and pliable tissue and the adequate coverage of tendon - gliding surface is necessary for a soft tissue defect of the hand with exposure of bone, tendon and muscle. This report will discuss our experience with anterolateral thigh fascial free flap for the reconstruction of the soft tissue defect of the hand. Methods: Between February 2004 and August 2008, seven patients with full - thickness soft tissue defects of the hand were reconstructed by means of a composite anterolateral thigh fascial free flap. There were soft tissue defects associated with trauma (n=5), scar contracture (n=1) and necrosis due to ischemia (n=1). Flaps were harvested from the anterolateral thigh as adipofascial flaps with only a small sheet of fascia and fatty tissue above it. The fascia and the skin of the donor site was closed directly and delayed split - thickness skin graft was performed. Result: All flaps survived completely. The size of the transferred flap ranged from $2{\times}4cm$ to $5{\times}8cm$. Thin flap coverage was possible without secondary debulking operations. It left minimal donor site morbidity with a linear scar. In one case, the thigh muscle herniation in the donor site was developed. Conclusion: The anterolateral thigh fascial free flap provided thin and pliable tissue which can establish a tendon - gliding mechanism, minimal bulk, minimal donor site morbidity. The disadvantages of this technique were the need for a skin graft and the muscle herniation of donor site.

• 한국결정성장학회지
• /
• 제11권5호
• /
• pp.224-230
• /
• 2001

초박막 게이트 유전막 및 비휘발성 기억소자의 게이트 유전막으로 연구되고 있는 $NO/N_2O$ 열처리된 재산화 질화산 화막의 특성을 D-SIMS(Dynamic Secondary Ion Mass Spectrometry), ToF-SIMS(Time-of-Flight Secondary Ion Mass Spectrometry), AES(Auger Electron Spectroscopy)으로 조사하였다. 시료는 초기산화막 공정후에 NO 및 $N_2O$ 열처리를 수행하였으며, 다시 재산화공정을 통하여 질화산화막내 질소의 재분포를 형성토록하였다. 재산화에 있어서 습식산화시 공정에 사용된 수소에 의한 영향으로 계면 근처에 축적된 질소가 Si≡N 결합을 쉽게 이탈함에 따라 방출이 촉진되어 건식산화에 비하여 질소의 감소가 더욱 두드러지게 나타났다. 재산화에 따른 질화산화막내 질소의 거동은 외부로의 방출과 기판으로의 확산이 동시에 나타난다. 재산화후 질화산화막내 축적된 질소의 결합종을 분석한 결과, 초기산화막 계면근처의 질소는 SiON의 결합종이 주도적으로 나타나는 반면 재산화 후 새롭게 형성된 $Si-SiO_2$ 계면근처로 확산한 질소는 $Si_2NO$ 결합종이 주로 검출된다. SiON에 의한 질소의 미결합손과 $Si_2$NO에 의한 실리콘의 미겨랍손은 기억특성에 기여하는 결함을 포함하기 때문에 재산화 질화산화막내 존재하는 SiON과 $Si_2$NO 결합종은 모두 전하트랩의 기원과 관련된 결합상태로 예상된다.