• 한국초전도ㆍ저온공학회논문지
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• 제18권4호
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• pp.15-20
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• 2016

The effects of electron beam (EB) irradiation on the superconducting critical temperature ($T_c$) and critical current density ($J_c$) of YBCO films were studied. The YBCO thin films were irradiated using a KAERI EB accelerator with an energy of 0.2 MeV and a dose of $10^{15}-10^{16}e/cm^2$. A small $T_c$ decrease and a broad superconducting transition were observed as the EB dose increased. The value of $J_cs$ (at 20 K, 50 K and 70 K) increased at doses of $7.5{\times}10^{15}$ and $2.2{\times}10^{16}e/cm^2$. However, $J_cs$ decreased as the dose increased further. The X-ray diffraction (XRD) analysis showed that the c axis of YBCO was elongated and the full width at half maximum (FWHM) increased as the dose increased, which is strong evidence of the atomic displacement by EB irradiation. The transmission electron microscopy (TEM) showed that the amorphous layer formed in the vicinity of the surfaces of the irradiated films. The amorphous phase was often present as an isolated form in the interior of the films. In addition to the formation of the amorphous phase, many striations running along the a-b direction of YBCO were observed. The high magnification lattice image showed that the striations were stacking faults. The enhancement of $J_c$ by EB irradiation is likely to be due to the lattice distortion and the formation of defects such as vacancies and stacking faults. The decrease in $J_c$ at a high EB dose is attributed to the extension of the amorphous region of a non-superconducting phase.

• 비파괴검사학회지
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• 제25권2호
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• pp.74-80
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• 2005

물체의 형상검사를 위한 검사 방법 가운데 광삼각법을 이용한 레이저 삼각검사 방식은 원격 비접촉식의 고정밀, 고속 측정이 가능하다는 장점이 있다. 이러한 레이저 삼각측정 방식은 평면뿐만 아니라 경사면에 위치한 홀의 길이를 측정하는데 이용하고 있다. 그러나 기존의 방식으로는 렌즈의 초점 거리가 정해져 있었으므로 한정된 영역만을 측정할 수 있다는 단점이 있었다. 이러한 문제는 CCD 카메라와 측정 대상체 사이의 거리를 변화시키는 간단한 방법으로 해결할 수 있다. 이를 원리로 좀더 효율적인 방식을 채택한 것이 가변적인 초점 거리를 갖는 줌 렌즈를 사용하는 방법이다 주 논문에서는 가변적인 초점 거리를 갖는 줌렌즈를 사용함으로써 측정 물체의 크기에 따라 렌즈 배율을 최적화하여 개선된 분해능을 갖는 형상측정 시스템을 제안하였고 정밀도의 향상을 실험적으로 실증하였다.

• 대한치과기공학회지
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• 제39권4호
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• pp.235-242
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• 2017

Purpose: The aim of this study was to evaluate the marginal and internal gap of zirconia copings fabricated by CAD/CAM system and to research the effect of cement space on the fit of zirconia prosthesis. Methods: Zirconia copings were designed using 3shape software and then milled from presintered zirconia blocks by Kavo dental milling machine. The cement space was set at $0{\mu}m$ around the margins for all groups, and additional cement space appling 1 mm above the finish lines of tooth. The samples were classified into 4 groups according to the cement space setting(Cs-0, Cs-40, Cs-80, Cs-120). Replica technique used to investigate marginal and internal gap. The silicone film thickness was recorded using a optical microscope with image software analysis system at 75${\times}$magnification. The assessment performed on the six points in bucco-lingual and mesio-distal sections(4 groups, 10 copings per group, 12 measuring points per coping). The data were statistically analyzed with one-way ANOVA followed by pair-wise Tukey's post hoc tests(${\alpha}$<0.05). Results: Better marginal and internal fit values were exhibited by $80{\mu}m$ cement space. The results showed that different cement space values had statistically significant effect on the marginal and internal gap of zirconia copings(p<0.001). The gap of margin and axial wall area was smaller than that the gap of occlusal area in all groups(p<0.001). Conclusion : Effect of different cement spaces on the marginal and internal gap of zirconia copings.

• Restorative Dentistry and Endodontics
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• 제23권2호
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• pp.682-689
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• 1998

The purpose of this study was to evaluate the sealing ability of the Microseal$^{(R)}$, which was new obturation system made by Tycom company, U.S.A. Forty-five extracted single-rooted human teeth were resected at cemento-enamel junction and divided three groups. All canals were prepared using Profile system, and then each group was obturated by lateral condensation technique (group 1), vertical condensation technique (group 2) and Microseal$^{(R)}$ condensation technique (group 3) with root canal sealer. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$ and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were resected horizontally at 1 mm (level I), 2 mm (level II), 3 mm (level III) from the anatomical root apex using low speed microtome and examined with Image analyzer (IBASR, Zeiss co., Germany.) at ${\times}25$ magnification. The gab between the canal wall and the filling material, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was expressed percentage by calculating the ratio of the area of the resin to the total area of the canal and was analyzed statistically (one-way ANOVA). The results were as follows; 1. The mean ratio of leakage (%) was 6.46% at group 1, 3.06% at group 2, 11.27% at group 3. 2. When evaluating the ratio of leakage at the three levels, there was level I> level II> level III in all groups. Especially, the difference between level I and level III was statistically significant (p<0.05). 3. When evaluating the ratio of leakage at the three groups, there was group 3> group 1> group 2 at all levels. Especially the difference between group 2 and group 3 was statistically significant (p<0.05).

• 치과방사선
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• 제29권1호
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• pp.261-274
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• 1999

Objectives: The purpose of this study was to evaluate the optimal distance and angle of observers by modulation transfer functions(MTFs) and receiver operating characteristics(ROCs), Material and Methods: Digital periapical radiograms were taken from 43 patients who have dental diseases(19 patients : dental caries. 12 patients : periapical lesions, 12 patients : periodontal diseases). Segmental images(4×4cm) were evaluated by 4 MTFs and ROC analysis. Results: The optimal distance(magnification) using MTF by Mannos & Sakrison was 12.97. and those by Nill. Ngan and Rao were 8.39, 4.78. 5.84 respectively. The optimal distance obtained from 4 radiologists by ROC analysis was 32cm(Az value: 0.89). and it was 40cm(Az value: 0.78) from 4 non-radiologists. There were significant differences of Az values between 4 radiologists and 4 non-radiologists at 24. 32 and 40cm (P<0.05). No significant differences of optimal distances were observed using 4 MTFs among +20, +10, 0, -10, -20 degrees(P>0.05). The optimal angle obtained from 4 radiologists by ROC analysis was +20 degree(Az value: 0.91). and no significant differences of Az values were observed among +20, +10, 0, -10 and -20 degrees(P>0.05). The optimal angle obtained from 4 non-radiologists by ROC analysis was 0 degree(Az value : 0.81). and no significant differences of Az values were observed among +20, +10, 0, -10 and -20 degrees(P>0.05). And there was significant difference of Az value between 4 radiologists and 4 non-radiologists at +20 degree(P<0.05). but no significant differences of Az values were observed among +10, 0, -10 and -20 degrees(P>0.05).

• Restorative Dentistry and Endodontics
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• 제24권3호
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• pp.482-489
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• 1999

The purpose of this study was to compare sealing ability between lateral condensation and continuous wave of condensation in depend of root canal curvature. In this study, we divided fifty-six human molar teeth into two group in depend of Schneider method, and then subdivided them into four experimental group (each group is composed of twelve teeth) by canal curvature and obturation method, and eight teeth were served as positive and negative controls. Specimens were prepared by Quantac 2000 series file and obturated by lateral condensation or System B. Specimens were immersed in india ink for 7 days, decalcified by 10% nitric acid, dehydrated by 75, 95 and 100% alcohol in order, cleared by methyl salicylate and then measured of dye penetration with stereomicroscope(${\times}6.5$ magnification) and Image Pro plus. The data were analyzed stastically by one-way ANOVA and Scheffe test. The data were as follows: 1. The mean leakage was $0.725{\pm}1.167$ for group A, $0.813{\pm}0.921$ for group B, $0.809{\pm}0.997$ for group C, $1.111{\pm}1.147$ for group D, but no significant difference among them(p>0.05). 2. Lateral condensation had better sealing ability than continuous wave of condensation, but no significant difference among them(p>0.05). 3. There was no significant difference between root canal curvature degree and microleakage(p>0.05).

• 한국광학회지
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• 제18권1호
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• pp.8-13
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• 2007

본 논문에서는 반사형 포토폴리머의 투과형 기록구조에서의 광학 특성을 분석하고 전반사 홀로그램 기법이 적용된 반사형 포토폴리머를 이용하여 미세패턴을 기록하였다. 투과형 포토폴리머는 대칭형 입사구조에서 $40^{\circ}$ 일 때 최대 효율을 보였으나 반사형 포토폴리머는 $60^{\circ}{\sim}80^{\circ}$에서 90% 이상의 회절효율을 보였다. 미세패턴 기록에서 10배 및 100배로 확대하여 측정한 결과 선 패턴과 점 패턴 간격 모두 $1{\mu}m$ 까지 구분할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.356-359
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• 2017

교육부의 운영계획에 따라서 학교당 1~2개 교실에 전자칠판(IWB, Interactive White Board)이 보급되었다. 따라서, 두상투영기(OHP, Overhead Projector)와 스크린 대신에 실물화상기와 전자칠판이 그 역할을 대신하게 되었다. 하지만 촬상소자와 디스플레이 장치의 발전 속도를 따라가지 못하고, 활용도가 떨어지는 경우가 많았다. 본 연구에서는 스마트폰의 카메라를 이용하여 고해상도의 이미지를 획득할 수 있도록 연구한다. 획득한 고해상도의 이미지를 전자칠판이나 대형 TV로 무선 통신으로 지연시간 없이 전송할 수 있도록 와이기그(WiGig, Wireless Gigabit) 기술을 이용한다. 또한 스마트폰 카메라에 넓은 화각(FOV, Field of View)의 렌즈를 탑재하여 출시하는 것에 반하여, 현미경 렌즈를 이용하여 스마트폰으로 특정 부분을 400배까지 확대하여 관찰할 수 있도록 한다. 본 연구결과로 교육 및 연구 현장에서 실시간 400배 확대의 활성화 자료로서 사용될 것이다.

• Radiation Oncology Journal
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• 제4권2호
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• pp.179-181
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• 1986

최근 방사선치료영역에 있어 CT의 역할은 매우 중요시되고 있다. 종래의 병기결정 등 진단적가치 이외에도 방사선치료분야에 있어서는 환자신체의 윤곽 종양침습 범위, 인접 정상구조물의 위치, 조직불균질성의 정도 등을 정확하게 파악할 수 있고 입체적영상의 재구성도 가능하여 주위 정상조직의 손상 없이 충분한 종양치료선량을 조사하는데 있어 거의 필수이라고 까지 할 수 있다. 이와 같은 진단용 CT상은 모두 실물크기를 일정 비율로 축소시킨 영상으로 기록 및 보관되고 있는 바 방사선치료계획시 이 축소된 CT상을 치료계획용 콤퓨터에 입력할 경우 같은 CT영상일지라도 치료의사에 따라서 또 입력할 때마다 조금씩 차이가 생길 수 있음으로 이와 같은 오차를 줄이기 위하여는 실물크기의 영상이 필요하게 된다. 저자들은 축소된 CT영상을 실물크기로 확대하기 위하여 overhead projector(3M사제)와 평면거울을 부착시킨 정맥주사용 Pole을 이용하여 값싸고 간단한 장치를 고안하였으며, 이를 사용하여 쉽게 실물크기영상을 치료계획용콤퓨터 (Thenac 2000, NEC제)의 입력판위에 얻을 수 있었기에 보고하는 바이다.

• 패션비즈니스
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• 제6권4호
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• pp.32-45
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• 2002

The purpose of this study is, to renew understanding the aesthetic value of a ruff collar and to expand the border of creation in designing as the source of inspiration being applied to an retro style by inquiring various ruff collars re-illuminated in the present-day fashion trend. The ruff collar investigated through the above historical contemplation became the source of inspirations in the current retro trend and was variously modified in modern fashion. In the 1980s, we can find a dignified and feminine image in graceful and exquisite suits or dresses. Especially, the spanish round ruff of the 2st period appeared on works by a lot of designers. From the application by designers like John Galliano in the latter half of the 80s, we can be well aware that the meaning of decoration was newly altered. In the 1990s, the ruff collar was shown in various fashion style, but it was what was reborn as a factor of modern fashion through a liberal compromise and harmony. Various style was shown from exaggeratedly swelling one to smaller one, which were more diversely applied than that of the 80s. A Medici collar and a Queen Elizabeth collar were also displayed being fitted to a modern sense by Vivienne Westwood and Louis F raud. A ruff in the 2000s was settled as a factor of modern fashion, exposing on works of designers more often than in the 1980s and 90s. The spanish round ruff appeared on garments, while a Medici collar and a Queen Elizabeth collar went out of sight. A new form of the ruff was regenerated by extreme magnification and simplification, and several designers like Issey Miyake and Alexander Mcqueen brought forward a new way in materials and technical skills. According to this research, a ruff collar developed as a fashion factor which characterizes a certain period of time, reflecting the aesthetical sense of Renaissance and turning into various and distinct forms. Afterwards, it exerted influence on modern fashion. This is offering the source of inspiration to contemporary designers.