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코경유 눈물주머니코안연결술 전 통상적인 이비인후과 의뢰의 임상적 효용성
장영준,김호창,서억수,Young Jun Jang,Ho Chang Kim,Eok Soo Suh 대한안과학회 2012 대한안과학회지 Vol.53 No.10
Purpose: To determine if routine otorhinolaryngologic referral prior to endonasal dacryocystorhinostomy (EN-DCR) is necessary. Methods: Two hundred thirty-seven eyes of 178 patients who were supposed to undergo EN-DCR were prospectively analyzed. Nasal endoscopy was performed by an ophthalmologist and the patients who had severe abnormality were referred to an otorhinolaryngologist. The patients were classified into 3 groups after a preoperative examination by an ophthalmologist and an otorhinolaryngologist; the number and success rate of each group were then investigated. Group A consisted of patients who had no nasal cavity abnormality, Group B consisted of patients with a nasal cavity abnormality but who received no treatment, and Group C consisted of patients who had a nasal cavity abnormality and received otorhinolaryngologic treatment. Results: The number of subjects in each group was 156 in Group A (87.7%), 12 in Group B (6.7%), and 10 in Group C (5.6%). The number of patients who were referred to the otorhinolaryngologist was 22 (12.3%). There was no statistical significance of success rate between the groups. Conclusions: Routine nasal endoscopic examination should be performed by an ophthalmologist prior to EN-DCR. Only patients with severe abnormal findings should be referred to an otorhinolaryngologist as the results from the present study show the percentage of patients having significant nasal abnormalities was found to be low (12%) and the success rate of EN-DCR revealed no statistical significance between the groups. This could help patients by saving time and expense. J Korean Ophthalmol Soc 2012;53(10):1392-1396
Si 도핑된 사면체 비정질 카본 코팅의 열 안정성 및 고온 내구성 특성
장영준(Young-Jun Jang),김원석(Won-seok Kim),장지웅(Ji-woong Jang),김종국(Jongkuk Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
수소를 포함하는 비정질 카본 (hydrogenated amorphous carbon, a-C:H)의 경우, 사용 온도 500 ℃ 이하에서 수소 손실에 따른 열분해와 코팅 막에서 취성이 발생하여 고온 환경으로의 적용에 있어 작동 온도가 제한된다. 이를 위해, 수소를 포함하지 않은 사면체 비정질 카본 (tetrahedral amorphous carbon, ta-C) 코팅이 대체 재료로 각광받고 있으나 sp<sup>3</sup> 분율과 경도가 높아 적용하는 코팅 막의 내열성과 내마모 특성은 우수하지만 상대 재료의 마모가 증가되는 단점이 있다. 이러한 문제해결과 고온에서의 작동 온도 증대를 위해, nitrogen, boron, silicon, fluorine 등 전이금속 (transition metal)을 포함하는 DLC 코팅 막 합성이 수행되고 있다. 특히, Silicon 이 도핑 된 DLC 코팅은 다습 환경, 고온에서의 마찰 효과와 내구성 증가에 있어 중요한 관심사로 공정 개발이 이루어졌다. 그러나, 현재까지의 많은 연구는 Thetramethylsilane (TMS, Si(CH<SUB>3</SUB>)<SUB>4</SUB>), SiH<SUB>4</SUB> gas 등을 기저 물질로 PE-CVD 방법을 활용한 연구가 대다수이며 원천적으로 낮은 경도 (10 ~ 20 GPa) 범위로 제한적이다. 따라서, 본 연구에서는 수소를 포함하지 않은 ta-C 코팅 중 Si doping 이 ta-C 코팅의 미세 구조, 기계적, 다양한 온도 환경에서의 트라이볼로지 특성 영향에 대한 연구가 수행되었으며 그 결과를 소개하고자 한다. In the case of hydrogen-containing amorphous carbon (a-C:H), thermal decomposition due to hydrogen loss and brittleness occurs in the coating film at a use temperature of 500 °C or less, which limits the operating temperature in application to a high-temperature environment. A tetrahedral amorphous carbon (ta-C) coating that does not contain hydrogen is gaining popularity as an alternative material. However, due to the high sp<sup>3</sup> fraction and high hardness characteristics, the coating film has excellent heat resistance and abrasion resistance, but there is a disadvantage in that the wear of the counterpart material is increased. In order to solve this problem and increase the operating temperature at high temperatures, synthesis of a DLC coating film containing a transition metal such as nitrogen, boron, silicon, and fluorine has been performed. In particular, silicon-doped ta-C coating has been developed as an important concern in increasing the friction effect and durability in a high humidity environment and high temperature. However, many studies to date have mostly used the PE-CVD method using Thetramethylsilane (TMS, Si(CH<SUB>3</SUB>)<sub>4</sub>), SiH<SUB>4</SUB> gas, etc. as base materials, and are limited to the low hardness (10 ~ 20 GPa) range. Therefore, in this study, a study on the influence of the microstructure, mechanical, and tribology characteristics of the ta-C coating on the high temperature environments.