CdTe의 Trap 準位

李京錫,李海翼,李載珍,董徹,金榮咸,姜泰遠 동국대학교 자연과학연구소 1984 자연과학연구 논문집 Vol.4 No.-

本 硏究에서는 Iodine을 dope시켜 Bridgman法으로 成長시킨 n-type CdTe를 admittance分光法을 이용하여 溫度變化에 따른 capacitance와 donductance를 測定하였다. capacitance와 conductance는 溫度增加에 따라 一般的으로 增加하나, 250K 근처에서 capacitance는 급격한 增加를 보이고 conductance는 極大値를 보인다. 이 conductance의 極大値 測定 周波數를 增加시키면 높은 溫度쪽으로 shift하는 것을 볼 수 있었고, 이것으로부터 구한 trap에너지準位, 電子放出率, trap濃度는 각각 E-0.42eV 2.14×10sec, 6.57×10cm이었다. Measurememts of the capacitance and the conductance as a function of tmeperature of I-doped n-type CdTe grown by the Bridgman method has been performed by means of the admittance spectroscopy. It is found that the capacitance and the conductance normally show trend of increase with temperature and the increase of the capacitance shows rapid change near 250K, whereas the conductance shows a peak there. This peak of the conductance shows shift toward the higher temperature with the measured frequency. The trap energy level, the electron emission rate and the trap concentration obtained from the set of these results are E-0.42eV 2.14×10sec, 6.57×10cm respectively.

Bi-factor MIRT True-Score Equating for Testlet-Based Tests

이규민(Gue min Lee),Won Chan Lee,Michael J Kolen,박인용(In Yong Park),Dong In Kim,Ji Seung Yang 한국교육평가학회 2015 교육평가연구 Vol.28 No.2

Lee and Lee (2014) proposed bi-factor multidimensional item response theory model (BFM) "observed-score" equating procedures. The main purposes of this study were to develop BFM "true-score" equating procedures, and to investigate applicability of the proposed procedures with actual data. Eight equating methods (including both true- and observed-score) based on dichotomous IRT (2-parameter logistic model: 2PL), polytomous IRT (graded response model: GRM), testlet response model (TRM), and BFM were compared with target equipercentile equating. Data for this study were from the Reading Comprehension test for a large-scale state assessment program, which consisted of several passages and corresponding groups of items. True- and observed-score equating methods based upon 2PL and BFM produced similar equating results. The GRM true- and observed-score equating methods provided equating results somewhat different from others, and more similar to the target equipercentile equating. Lee와 Lee(2014) 연구는 혼합형 검사에서의 bi-factor 다차원 문항반응모형을 적용한 IRT "관찰점수" 동등화 절차를 제안하였다. 이 연구는 Lee와 Lee(2014) 연구의 추수연구로 단위검사를 대상으로 bi-factor 다차원 문항반응모형을 적용한 IRT "진점수" 동등화 절차를 제안하고, 그 적용 가능성을 실제 자료를 이용하여 탐색하고자 하였다. 이를 위해 단위검사로 구성된 대규모 독해 검사 자료를 이용하여, 2모수 로지스틱 모형(2-parameter logistic model: 2PL), 등급반응모형(graded response model: GRM), 단위검사모형(testlet response model: TRM), bi-factor 모형(bi-factor model: BFM)을 적용하였으며, 관찰점수 및 진점수 동등화를 시행하여 총 8개의 동등화 방법을 적용하고, 산출된 결과를 동백분위 동등화 결과와 비교하였다. 연구 결과, 2PL과 BFM을 적용한 관찰점수 및 진점수 동등화는 유사한 결과를 산출하였으며, GRM을 적용한 관찰점수 및 진점수 동등화 방법은 다른 방법들과 다소 차이를 보이는 결과를 산출하였고, 비교 기준이 된 동백분위 동등화 결과와 보다 유사한 결과를 보였다.

Deletions of 9p21 and TP53 in Bladder Cancer

Park, W.-S Korean Academy of Medical Science 1996 Journal of Korean medical science Vol.11 No.3

간호전공과 비 간호전공 여대생의 모유수유 지식과 태도, 실천 지속 의지에 대한 연구

김수정,김희진,동민영,박소민,송예슬,이고은,이승만,장지은,정유진,최예슬 이화여자대학교 간호과학대학 2013 이화간호학회지 Vol.- No.47

Purpose: This study was conducted as benchmark to improve breast-feeding educational programs by comparing knowledge, attitude, and practical volition between female nursing college students and non-nursing college students. Method: The survey was conducted on 236 female students from ‘E’ and ‘Y’ Universities which were located in Seoul. The sample consisted of 114 nursing and 122 non-nursing college students. The data were collected using self-administered questionnaires from October 25 to December 17, 2012. The collected data were analyze dusing SPSS20.0. Result: The nursing college students’ level of knowledge, attitude and practical volition toward breast feeding was higher than non-nursing college students. There was positive correlation between knowledge and practical volition and attitude and practical volition about breast-feeding in nursing college students. But non-nursing college students had positive correlation between knowledge and attitude, and knowledge and practical volition about breast-feeding. Conclusion: Based on the results of the research, there was a correlation between knowledge, attitude, and practical volition toward breast feeding. It was suggested that technical knowledge of breast feeding be offered to female college students, as well as nursing college students. It could help them have the right information on breast feeding. It was also suggested that educational programs to reinforce emotional⋅practical attitude based on the knowledge of breast feeding be developed. Also, this study suggested that female students get their practical education in breast feeding under any circumstances with the practical volition to breast feed. Improving the knowledge, attitude, and the practical volition toward breast feeding, will increase the rate of breast feeding.

Response of plasma rotation to resonant magnetic perturbations in J-TEXT tokamak

Yan, W,Chen, Z Y,Huang, D W,Hu, Q M,Shi, Y J,Ding, Y H,Cheng, Z F,Yang, Z J,Pan, X M,Lee, S G,Tong, R H,Wei, Y N,Dong, Y B IOP 2018 Plasma physics and controlled fusion Vol.60 No.3

<P>The response of plasma toroidal rotation to the external resonant magnetic perturbations (RMP) has been investigated in Joint Texas Experimental Tokamak (J-TEXT) ohmic heating plasmas. For the J-TEXT’s plasmas without the application of RMP, the core toroidal rotation is in the counter-current direction while the edge rotation is near zero or slightly in the co-current direction. Both static RMP experiments and rotating RMP experiments have been applied to investigate the plasma toroidal rotation. The core toroidal rotation decreases to lower level with static RMP. At the same time, the edge rotation can spin to more than 20 km s<SUP>−1</SUP> in co-current direction. On the other hand, the core plasma rotation can be slowed down or be accelerated with the rotating RMP. When the rotating RMP frequency is higher than mode frequency, the plasma rotation can be accelerated to the rotating RMP frequency. The plasma confinement is improved with high frequency rotating RMP. The plasma rotation is decelerated to the rotating RMP frequency when the rotating RMP frequency is lower than the mode frequency. The plasma confinement also degrades with low frequency rotating RMP.</P>

박판주조법으로 제조된 Zr계 벌크 비정질 합금의 미세파괴기구

이정구,이동근,이성학,김낙준,조경목,박익민 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.2

The mechanical property improvement of a strip-cast Zr-base bulk amorphous alloy was explained by clarifying fracture mechanisms. Effects of crystalline phase particles formed in the amorphous matrix during strip casting on strength, ductility, and fracture toughness were explored in detail by directly observing microfracture processes using an in situ loading stage installed inside a scanning electron microscope (SEM) chamber. The compressive and fracture toughness test results indicated that ductility, strength, and fracture toughness of the atrip-cast amorphous alloy were higher than those of the as-cast monolithic amorphous alloy, although the strip-cast alloy contained a considerable amount (4.5 vol. %) of hard, brittle crystalline particles. This improvement of mechanical properties in the strip-cast alloy could be plausibly explained by mechanisms of (1) blocking of crack propagation, (2) formation of multiple shear bands, and (3) crack deflection by crystalline particles. Such property improvement presents new applicability of the strip-cast amorphous alloy containing crystalline particles to structures and components requiring excellent fracture toughness.

구기자 및 구기엽 추출물의 피부과색소 조절효과

김동희 ( Dong Hee Kim ),이수연 ( Soo Yeon Lee ),김남경 ( Nam Kyung Kim ),윤보경 ( Bo Kyung Youn ),정다솜 ( Da Som Jung ),최은영 ( Eun Young Choi ),홍소리 ( So Ri Hong ),윤지영 ( Ji Young Yoon ),강명화 ( Myung Hwa Kang ),이진영 ( J 한국응용생명화학회(구 한국농화학회) 2011 Journal of Applied Biological Chemistry (J. Appl. Vol.54 No.4

구기자, 건조구기엽, 생구기엽 추출물의 미백효과를 검증하였다. Tyrosinase 저해활성 측정결과 건조구기엽 에탄올추출물 500 μg/mL에서 44%의 저해활성을 나타내었으며, melanoma cell (B16F10)에서의 melanin 생합성 저해율 측정결과 건조구기엽 에탄올 추출물 50 μg/mL에서 14%의 저해효과를 나타내었다. 구기자, 건조구기엽, 생구기엽 추출물을 처리한 B16F10군 에서는 tyrosinase protein의 발현이 처리하지 않은 군보다 감소 하였다. 특히, 건조구기엽 추출물의 경우 tyrosinase의 단백질 발현량을 많이 저해하였다. 결과적으로 건조구기엽 추출물의 미백활성이 가장 우수하였으며, 식품 및 화장품의 기능성 소재로 이용이 가능할 것으로 판단된다. The objective of the present study was to evaluate the skin whitening effect of the extracts, Lycii fructus (LF), Dry-L. foilum (DLF) and Fresh-L. folium (FLF). Tyrosinase inhibition activities was 44% in DLF ethanol extracts at a 500 μg/mL. When the tyrosinase activities in B16F10 murine melanoma cell were tested, the activities in DLF ethanol extracts was 14% at a 50 μg/mL concentration. The protein expression of microphthalmia-associated transcription factor, tyrosinase related protein 1 (TRP-1), TRP-2, and tyrosinase, which are all melanin related factors, showed that LF, DLF and FLF extracts inhibited the protein bio-synthesis in B16F10 melanoma cell. Especially the DLF extract showed greater decrease of protein expressions. Results indicate that the DLF extract tested in the present study had skin whitening activity and can be used as a function a ingredients for food and cosmetic compositions.

유리系 內의 Ferrite의 Mossbauer Spectra

安振盛,金俊植,李敬行,趙壽烈,董徹,洪致裕 동국대학교 자연과학연구소 1984 자연과학연구 논문집 Vol.4 No.-

本 硏究는 5NiO-5CdO-10Fe₂O₃-30Na₂CO₃-10SiO₂(mole %)유리계에 대한 Mossbauer parameter의 溫度依存性을 조사하였다. Mossbauer spectrum은 한쌍의 Quadrupole doublet의 중첩으로 fitting하였으며 이중 하나는 tetrahedral site,다른 하나는 octahedral site이다. 상대적인 共鳴吸收面積比로부터 octahedral site와 tetrahedral site에 대한 Debye temperature를 계산하여 본 결과 각각 418K, 449K 임을 알았다. 또한 θ?값들을 이용해 least square method로 isomer shiftdral site의 壓力依存系數 α와 2.97×10?mm/sec K, I.S(0)일때의 를 평가해본 결과 octahedral site의 α는 2.97×10?mm/sec K,I.S(0)는 tetrahedral site이고 α의 3.2305×10?mm/sec K, I.S(0)는 0.276mm/sec임을 알았다. 그리고 quadrupole splitting은 측정온도가 증가함에 따라 서서히 감소함을 알았다. The temperature dependence of the Mossbauer parameter for 5NiO-5CdO-10Fe₂O₃-30Na₂CO₃-10SiO₂(mole %) quenched glass system was investigated. The spectra were fitted as superposition of a pair of quadrupole double ; One is for the tetrahedral site and the other is for the octahedral site. From the relative absorption area ratios of the spectra, the Debye erature of two sites were calculated to be 418K and 449K for the octahedral site and the ?edrai site, respectively. From these Debye temperatures, We can see that the isomer shifts and the coefficients αof the pressure dependence of the isomer shift are 0.456mm/sec, 2.97×10?mm/sec K for octahedral site and 0.276mm/sec K, 3.2305×10?mm/sec K for ?edral site. Also, we can see that the quadrupole splittings of two sites are gradually decresed the increase of the measuring temperature.

ECAP으로 제조된 초미세립 저탄소강의 단열성 전단밴드의 미세조직 변화

황병철,이성학,김용찬,김낙준,신동혁 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.5

The object of the present study is to investigate the microstructural development of the adiabatic shear band formed by dynamic torsional experiments of ultra-fine-grained low-carbon steels fabricated by equal channel angular pressing (ECAP). Dynamic torsional tests were conducted on four steel specimens, two of which were annealed after ECAP, using a torsional Kolsky bar, and then the test data were compared via microstructures, tensile properties, and fracture mode. The ECAP'ed specimen consisted of very fine, equiaxed grains of 0.2 !Am in size, which were slightly coarsened and had an equiaxed shape after annealing. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen, and their width was smaller in the ECAP'ed specimen than in the 1-hr annealed specimen, although they were not found in the 24-hr annealed specimen. Ultra-fine, equiaxed grains of 0.05~0.2 μm in size were formed inside the adiabatic shear band, and their boundaries had characteristics of high-angle grain boundaries. These phenomena were explained by dynamic recovery and recrystallization due to the highly localized plastic deformation and temperature rise occurred within the shear band. The temperature rise in the shear band formation process was inferred to be above 540℃ from the observation of spheroidization behavior of cementites in pearlite grains. (Received February 7, 2005)

TiN, TiCN, CrN 박막의 고온 산화

백창현,홍주화,위명용,김기영,이동복 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.8

The oxidation behavior of TiN, TiCN and CrN coatings sputtered on a steel substrate was investigated at 850℃ in air. Both TiN and TiCN oxidized to Tio₂ while CrN oxidzed to Cr₂O₃. The oxidation resistance decreased in the order of CrN, TiN and TiCN. During oxidation, the outward diffusion of substrate elements such as Fe, Si occurred to a certain degree. The enrichment of substrate element of Cr at the oxide scale and the depletion of nitrogen at the lower part of the unoxidized CrN coating were observed.