Gan p-i-n 자외선 검출기 제작 및 특성

조현경,김치선,홍창희 한국물리학회 2002 새물리 Vol.45 No.3

GaN p-i-n ultraviolet photodetectors grown by metalorganic chemical vapor deposition have been fabricated and their performances investigated. Under the optimized growth conditions of p-GaN, the detectors with a high visible blindness were successfully achieved and also the effect of p-layer thickness on their characteristics explored. For optimized p-i-n photodetector with 1000 Å thick p-layer, the visible-to-UV rejection ratio and the responsivity were over 106 and 0.19 A/W at 352 nm, respectively. 유기금속 화학 기상증착법으로 GaN p-i-n 구조를 성장하여 자외선 검출기를 제작하고 그 특성을 조사하였다. p-GaN의 성장조건의 최적화를 통하여 고효율의 가시빛 맹목(visible blindness)을 가진 p-i-n 검출기가 제작되었으며, 또한 p층의 두께에 따른 검출기의 특성을 분석하였다. 그 결과 두께가 1000 Å의 p층을 가진 p-i-n 구조에서 352 nm의 피크 파장에서 반응도(responsivity)가 0.19 A/W, 반응비(rejection-ratio)가 106이상인 고품위 자외선 검출기를 구현하였다.

2년간 혈액투석막 재사용의 임상경험

조현경 關東大學校 醫科大學 醫科學硏究所 2003 關東醫大學術誌 Vol.7 No.1

Hemodialyzer reuse has been widely used in the United States, but it is not a common practice in Korea. In our institution, we have reprocessed high flux hemodialyzers since March 2000. Patient survival was calculated by Kaplan-Meier analysis (n=68). Kt/Vurea on the first, 3rd, 9th and 15th reuses(n=52). We used high-flux synthetic membrane (polyester-polymer alloy, FLX-l5GW, Nikkiso, Japan : 1.5m2) for reuse. Dialyzers were reprocessed by an automated machine using Renalin (Renatron: Renal system, Minntech, USA). Cumulative survival rates during reuse at 6 month, 1 year, 2 year were 98.4%,96.6% and 87.8%, respectively (1-year survival rate on single use : 95.2%). Kt/Vurea was not different statistically with the increasing number of reuse (first : 3rd reuse 9th reuse 15th reuse= 1.27 ± 0.3 : 1.30 ± 0.5 : 1.31 ± 0.3 1.32 ± 0.3,p =NS) and with single use and reuse(1.31 ± 0.3 vs 1.29 ± 0.3, p = NS). Mean average number of reuse was 16.6 ± 3.8 time. In conclusion, comparable survival rate can be achieved upto 2 year with hemodialyzer reuse and Kt/Vurea with high flux synthetic membrane was not decreased until 15 reuses.

안전을 우리 생활공간으로 가져온 사회적경제

조현경 (재)아이쿱협동조합연구소 2018 생협평론 Vol.- No.30

2009 개정 교육과정 국어교과서 작품을 활용한 독서치료가 초등학생의 자아존중감 향상에 미치는 효과

조현경,손현동 한국교육치료학회 2015 교육치료연구 Vol.7 No.3

이 연구의 목적은 초등학생의 자아존중감을 향상시키기 위해 2009 개정 교육과정 국어교과서 작품 을 활용한 독서치료 프로그램을 개발하여 그 효과를 알아보는데 있다. 이를 위해 2009 개정 교육과 정 초등학교 3학년 국어교과서 작품을 분석한 후 작품을 선정하였다. 그런 후에 10회기의 독서치료 프로그램을 구성하였다. 이 프로그램의 효과성을 확인하기 위해 광주광역시에 소재한 M 초등학교 3 학년 학생을 대상으로 실험집단에 창의적 재량활동 시간을 이용하여 1회기 40분씩 총 10회기의 독 서치료 프로그램을 실시하였다. 그 결과, 실험집단은 통제집단보다 자아존중감 전체 점수가 유의하 게 향상되었다. 자아존중감 하위 요인 중에는 일반적, 사회적, 학업적 자아존중감은 유의한 향상을 보였으나, 가정적 자아존중감은 유의하지 않았다. 이 연구는 국어교과서 작품을 독서치료에 활용함 으로써 학교 현장 적용에 용이할 수 있도록 자료를 제공하였다는 점에서 의의를 찾을 수 있다. The purpose of this study was to examine the effect of bibliotherapy program based on a korean language textbook of 2009 Educational Curriculum Revision on the improvement of elementary school students' self-esteem. The subjects in this study were 51 children recruited from M elementary school in Gwangju metropolitan city. The experimental group received 10 sessions of the bibliotherapy program. The results of this study were as follows; First, the experimental group showed a significant increase in the level of self-esteem compared to the control group. Second, the experimental group showed a significant increase in the level of general, social and schoolwork related self-esteem, but no significant increase in the level of homely self-esteem as compared to the control group. These results imply that the bibliotherapy program may have significant effect on the improvement of elementary school students’ self-esteem.

Cataracts among Adults Aged 30 to 49 Years: A 10-Year Study from 1995 to 2004 in Korea

조현경,나경선,전은정,정성근 대한안과학회 2013 Korean Journal of Ophthalmology Vol.27 No.5

Purpose: To investigate the long-term characteristics of cataracts among adults aged 30 to 49 years in Korean over a span of 10 years. Methods: Subjects between the ages of 30 to 49 years who underwent cataract surgery at St. Mary’s Hospital from 1995 to 2004 (n = 976) were included. Patients with a history of ocular trauma, uveitis, other ocular or systemic diseases, and congenital cataracts were excluded. Additional information including type of lens opacity, urban/rural region, and pre- and postoperative visual acuities were analyzed. Lens opacity grading was conducted using Lens Opacity Classification System III. The Cochran-Armitage proportion trend test was used to analyze vision changes with the passage of time. Results: Among the patients who had undergone cataract surgeries, 8.8% (976 / 11,111) met the inclusion criteria. The mean age was 41.7 ± 5.45 years. Gender breakdown of the patient population included 79.0% male and 21.0% female. In terms of home environment, 60.9% were from an urban region and 39.1% from a rural region. Opacity type included anterior polar (AP), posterior subcapsular (PSC), AP and PSC, cortical, and nuclear in 35.7%, 35.1%, 7.0%, 6.0%, and 5.4% of patients, respectively. At a 2-month postoperative follow-up appointment, 92.7% of patients showed a best-corrected visual acuity of more than 20 / 40. Conclusions: Predominance of AP and PSC opacities as well as male patients was observed in this study population.

지속성 신대체 요법

조현경 關東大學校 醫科大學 醫科學硏究所 2003 關東醫大學術誌 Vol.7 No.2

Intermittent hemodialysis has been used to treat patients with acute renal failure. But use of intermittent hemodialysis is less desirable in the patient who is hypotensive or hemodynamically unstable, because hypotesion is common complication of intermittent hemodialysis. For that reason, the use of continuous renal replacement therapy is increasing as alternative approach. Because major advantage of continuous renal replacement therapy is the slower rate of solute or fluid removal, continuous renal replacement therapy is generally better tolerated than intermittent hemodilaysis. There are many variations of continuous renal replacement therapy. The different modalities are categorized according to the vascular access characteristics - venovenous or arteriovenous and mechanism of solute removal - filtration, dialysis or diafiltration. In addition to being better tolerated hemodynamically, continuous renal replacement therapy is also as efficient in removing immunomodulatory substances in sepsis and allows better nutritional support. Although there are several controversies about outcome of continuous renal replacement therapy, continuous renal replacement therapy is firmly established as a modality renal replacement therapy in the ICU.

사회적경제 생태계 조성을 둘러싼 협동조합 관련 언론 보도 심층 분석

조현경 (재)아이쿱협동조합연구소 2015 생협평론 Vol.- No.21

복합레진의 충전방법에 따른 변연접합성에 관한 주사전자현미경적 연구

조현경,박동수,이찬영,이정석 大韓齒科保存學會 1988 Restorative Dentistry & Endodontics Vol.13 No.1

The purpose of this study was to evaluate the marginal adaptation of Class Ⅴ resin restorations by the filling techniques. The cavities were filled with Hellosit?? light curing composite resin system in accordance with the following three filling techniques-bulk·pack placement technique, apical to occlusal layering placement techique, and buccolingual layering placement technique. And the interface between the restoration and the tooth structure was observed with scanning electron microscope. The following results were obtained. 1. Marginal adaptation of enamel showed excellent irrespective of the filling techniques. 2. Marginal leakage of dentin was observed irrespective of the filling techniques. 3. No difference of marginal adaptation according to the filling techniques was observed in light curing composite resin.

p-형 Si(100) 기판에 성장시킨 강유전 Bi4-xNdxTi3O12 (x=0.85) 박막의 축 정렬에 따른 전기적 특성 변화

조현경,김상수,김진원,이승우 한국물리학회 2008 새물리 Vol.56 No.3

Neodymium-substituted Bi$_{4}$Ti$_{3}$O$_{12}$ (Bi$_{4-x}$Nd$_{x}$Ti$_{3}$O$_{12}$, x=0.85, BNdT) thin films were deposited on {\it{p}}-type Si(100) substrates by using a chemical solution deposition method. When the film preparation process was changed, the preferred orientations of the BNdT films exhibited dramatic differences; random or {\it{c}}-axis. Well-characterized {\it{C-V}} curves demonstrated the ferroelectric nature of the BNdT thin films prepared by using different processes. The frequency-dependant {\it{C-V}} curves of the BNdT thin films showed high-frequency stability from 10$^{2}$ to 10$^{7}$ Hz, which can be adapted for microwave and high-speed memory applications. The dielectric constants and the fixed charge densities of the randomly orientated and the {\it{c}}-axis-oriented BNdT thin films were calculated as 340 and 410 and as 2.6 $\times$ 10$^{11}$/cm$^{2}$ and 2.9 $\times$ 10$^{11}$/cm$^{2}$, respectively. From the leakage current analysis, the dominant current conduction mechanism of both the randomly-oriented and $c$-axis-oriented BNdT thin films on {\it{p}}-type Si (100) substrates was found to be Schottky emission with barrier heights of 0.05 $\sim$ 0.1 eV at high voltages. 화학적 용액 증착 법을 이용하여 {\it{p}} -형 Si(100) 기판에 네오디뮴 (Nd)으로 치환된 Bi$_{4}$Ti$_{3}$O$_{12}$ (Bi$_{4-x}$Nd$_{x}$Ti$_{3}$O$_{12}$, x=0.85, BNdT) 박막을 성장시켰다. BNdT 박막 제작 과정을 다르게 하여 크게 다른 배향성 (축 방향으로 정렬되지 않은 (random) 박막과 {\it{c}}-축 방향으로 정렬된 박막)을 갖는 박막을 성장시킬 수 있었다. {\it{C-V}} 특성 곡선으로부터 이들 박막의 강유전 특성을 비교, 분석하였고 10$^{2}$ $\sim$ 10$^{7}$ Hz의 측정 주파수 범위 내에서 안정적인 {\it{C-V}} 특성 곡선을 보여 이 BNdT 박막의 마이크로 웨이브와 고속 메모리 소자로서의 응용 가능성을 보여주었다. 또 축 방향으로 정렬되지 않은 박막과 {\it{c}}-축 방향으로 정렬된 BNdT 박막의 유전 상수와 고정 전하 밀도는 각각 340, 410과 2.6 $\times$ 10$^{11}$/cm$^{2}$, 2.9 $\times$ 10$^{11}$/cm$^{2}$으로 계산되었다. 누설 전류 밀도 분석으로부터 {\it{p}} -형 Si(100) 기판에 직접 성장 시킨 BNdT 박막의 높은 인가 전압에서의 전기 전도 메카니즘은 0.05 $\sim$ 0.1 eV의 장벽 높이를 갖는 Schottky 방출 메커니즘임을 확인할 수 있었다.

고려시대라전칠기(高麗時代螺鈿漆器)에 관한 연구(硏究) -제작기법(製作技法)을 통해(痛駭) 본 변천과정(變遷過程)-

조현경 동아시아문물연구학술재단 2002 文物硏究 Vol.- No.6