30° 이내의 얼굴돌림을 보인 영아눈떨림환자에서 Modified Anderson 술식

양상철,전혜신,최희영 대한안과학회 2019 대한안과학회지 Vol.60 No.6

Purpose: To evaluate the efficacy of modified Anderson procedure in infantile nystagmus with face turn less than 30 degrees. Methods: This study was a retrospective review of the medical records of 13 consecutive patients who underwent a modified Anderson procedure for abnormal head position in infantile nystagmus at Pusan National University hospital from February 2002 to March 2017. We compared best-corrected visual acuity (logarithm of minimal angle of resolution, logMAR), refraction, degree of face turn, ocular motility, and angle of deviation preoperatively and at 1 week postoperatively, 6 months postoperatively, and the final visit. Recession of the yoke rectus muscles responsible for the slow phase of nystagmus was performed, depending on the direction of face turn; the medial rectus muscle of the eye to which the head was turned was recessed 10 mm, whereas the lateral rectus muscle of the contralateral eye was recessed 12 mm. Results: The mean age of the patients was 8.9 (2-25) years, and the mean follow-up period after surgery was 51.3 (6-183) months. Twelve patients (92.3%) had no residual head posture or <10° at 6 months postoperatively, and three patients (23.1%) achieved this outcome with an additional operation. The mean degrees of face turn were 22.30° before surgery and 3.85° postoperatively (p = 0.001). Best-corrected visual acuity (logMAR) was 0.41 in the better eye and 0.50 in the worse eye before surgery; this improved to 0.34 and 0.45 at 6 months postoperatively (p = 0.068 and p = 0.228, respectively). Despite the large recessions involved, only one patient showed mild limitation of abduction after surgery. Conclusions: The modified Anderson procedure may be effective for correcting abnormal head position in infantile nystagmus with face turn less than 30 degrees; patients were not overcorrected. 목적: 30° 이내의 얼굴돌림을 보인 영아눈떨림환자에서 Modified Anderson 술식의 효과를 알아보고자 하였다. 대상과 방법: 2002년 2월에서 2017년 3월까지 부산대학교병원에서 영아눈떨림으로 진단받고 이상두위교정을 위해 Modified Anderson 술식을 시행받은 13명의 의무기록을 통해 수술 전후 1주, 6개월, 최종 내원 시 최대교정시력, 굴절검사, 이상두위 정도, 안구운동 및 사시각을 비교하였다. 수술은 얼굴돌림에 따라 저속기에 해당하는 동향근인 2개의 수평직근을 후전시키는 술식(한눈 내직근 10 mm 후전술, 반대눈 외직근 12 mm 후전술)을 시행하였다. 결과: 대상 환자들의 평균 수술나이는 8.9세(2-25)였고, 수술 후 평균 51.3개월(6-183)의 추적 결과 수술 후 6개월에 얼굴돌림이 전혀 없거나 10° 이하로 교정된 경우가 12명(92.3%)이었고, 3명(23.1%)에서 추가 수술을 하였다. 수술 전 평균 얼굴돌림의 각도는 22.30°였고, 수술 후 6개월째 얼굴돌림의 각도는 3.85°로 유의한 호전을 보였다(p=0.001). 최대교정시력(logMAR)으로 수술 전 좋은 눈은 0.41, 나쁜 눈은 0.50이었고, 수술 후 6개월째 좋은 눈은 0.34, 나쁜 눈은 0.45로 각각 호전을 보였다(p=0.068, p=0.228). 많은 양의 후전술을 시행하였음에도 불구하고, 경도의 외전장애를 나타낸 환자는 1명이었다. 결론: 30° 이내의 얼굴돌림을 보인 영아눈떨림환자에서 이상두위는 Modified Anderson 술식으로 효과적으로 교정할 수 있었고, 과교정되지 않았다.

외상 이후 발생한 안와첨증후군 2예

양상철(Sang Cheol Yang),최희영(Hee Young Choi),전혜신(Hyeshin Jeon) 대한안과학회 2018 대한안과학회지 Vol.59 No.9

목적: 안와 내부 구조물의 직접적인 손상이 없는 안구의 둔상 이후 발생한 안와첨증후군 및 이의 치료 과정을 2예 경험하였기에 이를 보고하고자 한다. 증례요약: (증례 1) 쇠봉에 부딪친 후 시력 저하를 호소하는 50세 남자가 내원하였다. 좌안 교정시력은 광각불인지였으며 대광반사는 소실되어 있었다. 좌안의 완전 안검하수를 보였으며 부분적인 내전 및 하전을 제외한 전방향 안구운동제한을 보였다. 안와 자기공명 영상에서 시신경 및 시신경 주위 조직을 포함한 근원뿔 내 고음영이 관찰되었다. 스테로이드 정주 치료 3일째 시력은 안전수지로 회복되었고 수상 5개월째 안구운동 및 눈꺼풀 기능은 정상범위로 회복되었다. (증례 2) 굵은 철심에 우안을 부딪친 64세 여자로 수상 안의 교정시력은 20/25, 완전 안검하수, 부분적인 외전 및 하전을 제외한 전방향의 안구운동제한을 보였다. 안와 자기공명영상에서 시신경주위 및 직근 원위부의 조영 증강을 보였다. 스테로이드 정주 치료 후 2개월째 안검하수, 안구운동제한 및 시력은 모두 회복되 었다. 결론: 둔상에 의해 발생한 안와첨증후군이 고용량 스테로이드에 좋은 반응을 보였다. 외상에 의한 안와첨증후군에서 스테로이드 치료를 적극적으로 고려해 볼 수 있을 것으로 생각된다. Purpose: To report two cases of orbital apex syndrome caused by blunt orbital trauma without structural damage of the orbit. Case summary: (Case 1) A 50-year-old male came to our clinic complaining of visual loss after blunt orbital trauma by a metal bar. The best-corrected visual acuity was no light perception and light reflex was not observed in the affected eye. He also presented with complete ptosis and ophthalmoplegia with relative sparing of adduction and depression. High signal intensity of the orbital soft tissue including the optic nerve sheath was revealed using a T2-weighted image in magnetic resonance imaging. After starting steroid pulse therapy, his visual acuity improved to counting fingers on the third day. Ocular movement and levator function recovered to the normal range while visual acuity remained counting fingers. (Case 2) A 64-year-old female presented with complete ptosis after trauma to her right eyeball. The best-corrected visual acuity was 20/25 in the right eye. Complete ptosis and ophthalmoplegia with relative sparing of abduction and depression in the right eye were observed at the initial presentation. Magnetic resonance images showed enhancement of the right periphery optic nerve and distal rectus muscle. Two months after undergoing steroid pulse therapy, levator function and ocular movement recovered completely, and visual acuity improved to 20/20. Conclusions: The orbital apex syndrome caused by blunt orbital trauma showed good response to steroid pulse therapy. Steroid treatments may therefore be considered for the treatment of traumatic orbital apex syndrome. J Korean Ophthalmol Soc 2018;59(9):893-898

黃連 추출물이 산소자유기에 의해 손상된 배양 심근세포에 미치는 영향

양상철(Sang Cheol Yang),권강범(Kang Beom Kwon),조현익(Hyun Ik Cho),민영기(Young Gi Min),허재혁(Jae Hyuk Heo),김구환(Gu Hwan Kim),류도곤(Do Gon Ryu) 한의병리학회 2002 동의생리병리학회지 Vol.16 No.5

금속 3D 프린팅 공정 최적화를 통한 H13 공구강 조형체의 기계적 특성 향상

윤재철,최중호,이행나,김기봉,양상선,양동열,김용진,이창우,유지훈,Yun, Jaecheol,Choe, Jungho,Lee, Haengna,Kim, Ki-Bong,Yang, Sangsun,Yang, Dong-Yeol,Kim, Yong-Jin,Lee, Chang-Woo,Yu, Ji-Hun 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.3

In this study, H13 tool steel sculptures are built by a metal 3D printing process at various laser scan speeds. The properties of commercial H13 tool steel powders are confirmed for the metal 3D printing process used: powder bed fusion (PBF), which is a selective laser melting (SLM) process. Commercial H13 powder has an excellent flowability of 16.68 s/50 g with a Hausner ratio of 1.25 and a density of $7.68g/cm^3$. The sculptures are built with dimensions of $10{\times}10{\times}10mm^3$ in size using commercial H13 tool steel powder. The density measured by the Archimedes method is $7.64g/cm^3$, similar to the powder density of $7.68g/cm^3$. The hardness is measured by Rockwell hardness equipment 5 times to obtain a mean value of 54.28 HRC. The optimum process conditions in order to build the sculptures are a laser power of 90 W, a layer thickness of $25{\mu}m$, an overlap of 30%, and a laser scan speed of 200 mm/s.

SLM 공정으로 제작된 SKD61 공구강의 조형 특성에 관한 연구

윤재철,최중호,김기봉,양상선,양동열,김용진,이창우,유지훈,Yun, Jaecheol,Choe, Jungho,Kim, Ki-Bong,Yang, Sangsun,Yang, Dong-Yeol,Kim, Yong-Jin,Lee, Chang-Woo,Yu, Ji-Hun 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.2

In this study, two types of SKD61 tool-steel samples are built by a selective laser melting (SLM) process using the different laser scan speeds. The characteristics of two kinds of SKD61 tool-steel powders used in the SLM process are evaluated. Commercial SKD61 tool-steel power has a flowability of 16.68 sec/50 g and its Hausner ratio is calculated to be 1.25 by apparent and tapped density. Also, the fabricated SKD61 tool steel powder fabricated by a gas atomization process has a flowability of 21.3 sec/50 g and its Hausner ratio is calculated to be 1.18. Therefore, we confirmed that the two powders used in this study have excellent flowability. Samples are fabricated to measure mechanical properties. The highest densities of the SKD61 tool-steel samples, fabricated under the same conditions, are $7.734g/cm^3$ (using commercial SKD61 powder) and $7.652g/cm^3$ (using fabricated SKD61 powder), measured with Archimedes method. Hardness is measured by Rockwell hardness testing equipment 5 times and the highest hardnesses of the samples are 54.56 HRC (commercial powder) and 52.62 HRC (fabricated powder). Also, the measured tensile strengths are approximately 1,721 MPa (commercial SKD61 powder) and 1,552 MPa (fabricated SKD61 powder), respectively.

구리 모재를 이용한 초소형 히트파이프의 제작

조형철(Hyung Chul Cho),최장현(Jang Hyun Choi),박진성(Jin Sung Park),양상식(Sang Sik Yang),유재석(Jae Suk Yoo) 대한전기학회 2001 대한전기학회 학술대회 논문집 Vol.2001 No.7

기존교실의 오픈화수법과 열림학습공간의 평가에 관한 연구 : 제주지역 초등학교를 중심으로

김태일,양상철 제주대학교 산업기술연구소 1999 尖端技術硏究所論文集 Vol.10 No.2

Recently, there has been a trend to induce a new educational system of open school as an alternative to break from the traditional education. In spite of a short domestic history, the new system, which is the open school, widely spreaded to most of elementary schools in Cheju. Such system in Cheju was a global model designated by the Ministry of Education. However, there was a problem in the aspect of space application for open school, and it has a difficulty in properly confronting the developed education in the future. In this study, we analyzed the design drawings of the elementary schools executing the open school in Cheju and compared the factors ifluencing on the space applicability through site examination, which includes teachers' understanding on open school, the location and magnitude of school, and the number of students act. And by analyzing the phenomena from class applicability, we investigated the problems of open school space.

적층 가공된 3차원 조형체의 치밀화에 미치는 단일 melt pool 형상의 영향

최중호,윤재철,양동열,양상선,유지훈,이창우,김용진,Choe, Jungho,Yun, Jaecheol,Yang, Dong-Yeol,Yang, Sangsun,Yu, Ji-Hun,Lee, Chang-Woo,Kim, Yong-Jin 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.3

Selective laser melting (SLM) can produce a layer of a metal powder and then fabricate a three-dimensional structure by a layer-by-layer method. Each layer consists of several lines of molten metal. Laser parameters and thermal properties of the materials affect the geometric characteristics of the melt pool such as its height, depth, and width. The geometrical characteristics of the melt pool are determined herein by optical microscopy and three-dimensional bulk structures are fabricated to investigate the relationship between them. Powders of the commercially available Fe-based tool steel AISI H13 and Ni-based superalloy Inconel 738LC are used to investigate the effect of material properties. Only the scan speed is controlled to change the laser parameters. The laser power and hatch space are maintained throughout the study. Laser of a higher energy density is seen to melt a wider and deeper range of powder and substrate; however, it does not correspond with the most highly densified three-dimensional structure. H13 shows the highest density at a laser scan speed of 200 mm/s whereas Inconel 738LC shows the highest density at 600 mm/s.

냉간금형용 합금공구강 분말 및 적층조형체의 미세조직

강전연,윤재철,김호영,김병환,최중호,양상선,유지훈,김용진,Kang, Jun-Yun,Yun, Jaecheol,Kim, Hoyoung,Kim, Byunghwan,Choe, Jungho,Yang, Sangsun,Yu, Ji-Hun,Kim, Yong-Jin 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.3

A cold-work tool steel powder is used to fabricate 3-dimensional objects by selective laser melting using a high-pressure gas atomization process. The spherical powder particles form continuous carbide networks among the austenite matrix and its decomposition products. The carbides comprise Nb-rich MC and Mo-rich $M_2C$. In the SLM process, the process parameters such as the laser power (90 W), layer thickness ($25{\mu}m$), and hatch spacing ($80{\mu}m$) are kept fixed, while the scan speed is changed from 50 mm/s to 4000 mm/s. At a low scan speed of 50 mm/s, spherical cavities develop due to over melting, while they are substantially reduced on increasing the speed to 2000 mm/s. The carbide network spacing decreases with increasing speed. At an excessively high speed of 4000 mm/s, long and irregularly shaped cavities are developed due to incomplete melting. The influence of the scan pattern is examined, for which $1{\times}1 mm^2$ blocks constituting a processing layer are irradiated in a random sequence. This island-type pattern exhibits the same effect as that of a low scan speed. Post processing of an object using hot isostatic pressing leads to a great reduction in the porosity but causes coarsening of the microstructure.

기존교실의 오픈화수법과 열림학습공간의 평가에 관한 연구 : 제주지역 초등학교를 중심으로

김태일,양상철 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.2

Recently, there has been a trend to induce a new educational system of open school as an alternative to break from the traditional education. In spite of a short domestic history. the new system, which is the open school. widely spreaded to most of elementary schools in Cheju. Such system in Cheju was a global model designated by the Ministry of Education. However, there was a problem in the aspect of space application for open school, and it has a difficulty in properly confronting the developed education in the future. In this study. we analyzed the design drawings of the elementary schools executing the open school in Cheju and compared the factors influencing on the space applicability through site examination, which includes teachers' understanding on open school, the location and magnitude of school. and the number of students ect. And by analyzing the phenomena from class applicability, we investigated the problems of open school space.