• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.44-48
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• 2014

A liquid nitrogen-cooled prepolarization ($B_p$) coil made for ultra-low field nuclear magnetic resonance and magnetic resonance imaging (ULF-MR) designed to generate 7 mT/A was fabricated. However, with suspected internal insulation failure, the coil was investigated in order to find out the source of the failure. This paper reports detailed build of the failed $B_p$ coil and a number of analysis methods utilized to figure out the source and the mode of failure. The analysis revealed that pyrolytic graphite sheet linings put on either sides of the coil for better thermal conduction acted as an electrical bridge between inner and outer layers of the coil to short out the coil whenever a moderately high voltage was applied across the coil. A simple model circuit simulation corroborated the analysis and further revealed that the failed insulation acted effectively as a damping resistor of $R_{d,eff}=6{\Omega}$ across the coil. This damping resistance produced a 50 ms-long voltage tail after the coil current was ramped down, making the coil not suitable for use in ULF-MR, which requires complete removal of magnetic field from $B_p$ coil within milliseconds.

• Tuberculosis and Respiratory Diseases
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• 제62권1호
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• pp.62-66
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• 2007

A bronchial artery aneurysm is a rare condition, which needs optimal treatment due to the possibility of a life-threatening hemorrhage by rupture. The surgical removal of the aneurysm is the standard treatment. However, there are a few reports of coil embolization with a transcatheter. A 69 year-old man was referred for a further evaluation of a mass in the right hilum on chest radiography. He denied any respiratory symptoms. A chest CT scan showed a $3{\times}3{\times}4.5cm$ sized vascular mass with strong contrast enhancement on the right hilar area that originated from the bronchial artery. On the angiogram, the bronchial artery originated from the descending thoracic aorta at the T8 level. A bronchial artery aneurysm was catheterized selectively. and embolized successfully with a coil. After coil embolization, the selective bronchial arteriography confirmed complete occlusion. We report this case of bronchial aneurysm that was treated successfully with coil embolization.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.659-669
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• 1997

The goals of root canal instrumentation are complete debridement of pulp tissue, removal of microbes and affected dentin, and proper cleaning and shaping of the root canal space before obturation. Instrumentation with stainless steel files has been shown to produce undesirable results in canals, regardless of the improved technique or modified file type used. Nickel-Titanium(Ni-Ti) alloy has been shown to be exceptionally elastic, having a lower bending moment and lower permanent set after torsion, compared with similar gauge stainless steel. The purpose of this study was to evaluate the change of root canal prepared by Ni-Ti rotary and stainless steel instruments. Thirty-four single rooted teeth of similar shape and canal size were divided into three groups. The teeth were scanned by computed tomography before instrumentation. In group 1, canals were instrumented using a step-back technique with K-file. In group 2, canals were prepared with K-flex file using the same technique as group 1. Group 3 was prepared with nickel-titanium(Ni-Ti) rotary instrument using a manufacture's instruction. Instrumented teeth were again scanned using computed tomography, and reformated images of the uninstrumented canals were compared with images of the instrumented canals. K-flex file and Ni-Ti file caused significantly less canal transportation than K-file in the 8mm root canal section from the apex(p<0.05). K-flex file and Ni-Ti file produced more centered canal preparation than K-file in the 2mm section(p<0.05). Ni-Ti file maintained more precisely the center of the canal than K-flex file in the 10mm section (p<0.05). There was no difference in the removed volume of canals among each groups.

• Advances in pediatric surgery
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• 제8권2호
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• pp.138-142
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• 2002

Mesenteric and omental cysts are rare intra-abdominal lesions in childhood, and may present various clinical features such as an asymptomatic mass or an acute abdomen. Therefore, these entities are frequently misdiagnosed preoperatively or are found only incidentally at operation for other conditions. We analyzed our experiences of 19 cases in a 19 year period from 1981 to 1999, at College of Medicine, Catholic University of Korea. There were 12 boys and 7 girls with a mean age of 4.8 years (range, 3 days to 15 years). Common presenting symptoms were abdominal pain (47%), abdominal distension (31%), abdominal mass (24%), vomiting (15%) and fever (10%). Ultrasonography was the most preferred method of diagnosis. Other diagnostic modalities include CT, MRI, and abdominal ascites tapping in selected patients. Location of the mesenteric cysts was small bowel mesentery in nine, the right mesocolon and retroperitoneum in one, the left mesocolon in one, and the jejunum, sigmoid-colon mesentery in one. Most of the patients underwent cyst excision, but six patients required concomitant bowel resection for complete removal of the lesions, and two patients underwent unroofing and simple aspiration respectively. There was one mortality case due to sepsis.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권1호
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• pp.110-116
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• 1991

하악골 골절시 감염으로 인한 합병증에는 비유합, 부정유합, 감염에 의한 골수염, 치아 및 지지골 상실, 국소부위로부터 인접부위로 감염확장 등이 있다. 그 원인으로는 크게 국소요인과 전신요인으로 분류되는데 국소요인으로는 부적절한 고정과 수복, 감염 및 개조된 혈액공급을 들 수 있고 전신 요인으로는 부적절한 고정과 수복, 감염 및 개조된 혈액 공급을 들 수 있는 전신요인으로는 환자의 나이 및 대상장애 질환이나 primary bone disease, 영양결핍을 들 수 있다. 악골골절과 관련된 골수염은 조기에 적절한 고정 및 치료, 항생제 요법, 골절선상의 치아에 대한 치료, 전신적 저항성을 항진 시킴으로서 예방할 수 있다. 본 저자들은 하악골 골절수 이차감염으로 인한 골수염에서 골 이식의 일반적인 원칙인 감염이 없는 부위가 아닌 염증이 존재한 부위에 유리장골 이식술과 고압산소 요법을 병행하여 양호한 결과를 얻었기에 이에 보고하는 바이다.

• 청정기술
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• 제22권4호
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• pp.281-285
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• 2016

난분해성 1,4-다이옥산을 분해시키기 위하여 촉매습식과산화반응에 활성적인 Cu wire촉매를 사용하였다. Cu wire 촉매를 사용함으로써 1,4-다이옥산의 완전한 분해가 가능하였으나, 분해된 1,4-다이옥산은 완전 무기화($CO_2$와 $H_2O$로 전환)되지 못하고 중간생성물인 ethylene glycol diformate, oxalic acid, formic acid, formaldehyde, acetaldehyde 등으로 전환되었다. 1,4-다이옥산이 분해되어 없어짐에 따라 formaldehyde와 oxalic acid가 점진적으로 나타나기 시작하여 증가하다가 최고농도를 보인 후 다시 감소하였다. 이들 두 중간체의 최고농도 도달시점에 acetaldehyde의 농도가 급격히 증가하여 최고농도를 보인 후 다시 감소하였다. 이들 세가지 중간물질의 감소와 함께 ethylene glycol diformate, formic acid가 생성되기 시작하여 그 농도가 점진적으로 증가하였다. 이들은 연속적인 과정을 통해 생성되었다. Cu wire 촉매는 반응이 진행되는 동안 활성이 떨어지지 않고 매우 안정적이었다.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.38.1-38.10
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• 2020

Objectives: This study aimed to evaluate vital pulp tissue removal from different endodontic instrumentation systems from root canal apical third in vivo. Materials and Methods: Thirty mandibular molars were selected and randomly divided into 2 test groups and one control group. Inclusion criteria were a positive response to cold sensibility test, curvature angle between 10 and 20 degrees, and curvature radius lower than 10 mm. Root canals prepared with Hero 642 system (size 45/0.02) (n = 10) and Reciproc R40 (size 40/0.06) (n = 10) and control (n = 10) without instrumentation. Canals were irrigated only with saline solution during root canal preparation. The apical third was evaluated considering the touched/untouched perimeter and area to evaluate the efficacy of root canal wall debridement. Statistical analysis used t-test for comparisons. Results: Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument. Conclusions: Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during in vivo instrumentation is not entirely removed.

• 자원리싸이클링
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• 제3권1호
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• pp.9-16
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• 1994

Stellite 스크랩을 용융 NaOH로 분해하고 이로부터 Co가분말을 제조하였다. NaOH에 의한 Stellite 스크랩의 완전분해는 $750~800^{\circ}C$에서 Stellite에 대한 NaOH의 중량비 약 2로 1시간 이내에 이루어졌다. 함Co화합물은 X-선분석과 시차열중량분석에 의해 $Co_2O_3{\dot}H_2O$로 판명되었다. 함Co화합물은 HCl로 용해하여 $CoCl_2$용액으로 만들고, 그리고 용액의 pH를 조절하여 먼저 Fedldhs을 제거한 후, pH 약 13 또는 4에서 각각 2가 EH는 3가의 수산화코발트로 침전시켰다. 이 침전물들은 $400~500^{\circ}C$에서 수소로 환원하여 1.0~$1.5\mu\textrm{m}$크기의 고순도 Co로 제조되었다. Stellite스크랩으로부터 Co 회수율은 약 75~86 중량 %이었다.

• Journal of Chest Surgery
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• 제38권6호
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• pp.441-444
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• 2005

복강내 종양이 혈관을 통해 전이될 수는 있으나 우심장까지 침범되는 경우는 드물다. 자궁에서 기원하는 정맥내 평활근종증은 매우 드물며 조직학적으로는 양성이지만 임상적으로는 하대 정맥, 우심장 또는 폐동맥의 폐쇄를 동반함으로써 치명적인 결과를 초래할 수 있는 질환이다. 치료 방법은 심폐 순환기를 통한 완전 순환정지하에 종괴를 완전절제하는 것이다. 자궁에서 기원한 정맥내 평활근종증을 개복술과 개심술을 이용해 일차 수술로 성공적으로 치유하였기에 문헌고찰과 함께 보고하는 바이다.

• Journal of Chest Surgery
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• 제29권11호
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• pp.1276-1280
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• 1996

원발성 심장종양은 희귀성 때문에 병리학자, 심장내과의, 심장외과의에게 흥미로운 질환이다. 저자들은 수술치험한 세계적으로 희귀한 원발성 심장 연골육종을 보고하는 바이다. 환자는 37세의 여자환자로 본원에서 좌심방종양진단하에 1993년 6월 3일 입원하여 개심술하에서 완전 종양절제를 받은 바 있다. 그러나 조직소견상 연골육종이 진단되어 수술후 보조요법으로 방사선조사와 화학요법을 받은후 추적관찰하던 중 1995년 5월까지 종양 재발소견은 없었다. 그러나 환자는 두통과 전신성 경련으로 본원 신경외과에 입원하여 검사상 대뇌 전두엽부위에 단일 전이성 종괴가 발견되어 개두술하 종양절제가 가능하였으며, 조직 검사상 심장종양과 일치를 보였다. 환자는 건강한 상태로 퇴원하였다.