ZnO 투명전도막의 전기적 특성에 미치는 Al₂O₃의 도핑 농도의 효과

박강일,김병섭,이성욱,김현수,이세종,곽동주 경성대학교 공학기술연구소 2003 공학기술연구지 Vol.10 No.-

Al doped Zinc Oxide(ZnO:AI) films, which is widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. In this paper the effect of doping amounts of Al₂0₃ on the electrical, optical and morphological properties were investigated experimentally. The results show that the structural and electrical properties of the film are highly affected by the doping. The optimum growth conditions were obtained for films doped with 2 wt% of indium which exhibit a resistivity of 8.5×10^(-4)Ω-cm associated with a transmittance of 91.7 % for 840 nm in film thickness in the wavelength range of the visible spectrum.

A. 高校 科學 (生物·地球科學) 및 數學科 探究學習의 評價模型 定立과 評價紙 開發

李相協,權炳奎,林在圭,孫文求,吳岱燮,楊洪準,梁承榮,姜用熙,林成圭,金正遠,金吉民,兪正在 경북대학교 과학교육연구소 1982 科學敎育硏究誌 Vol.6 No.-

Currently the evaluation of high school science and mathematics learning has been too much knowledge-centered without concerning the inquiring ability or scientific attitude. This study, therefore, was made for the purpose of establishing of evaluation model for high school science (biology and earth science) and mathematics learning and its evaluation items. In this paper, the research was done about three fields, biology, earth science and mathematics. 1. For the biology, the evaluation methods of inquiry learning were studied with the foreign references, and proper evaluation items were suggested. 2. For the earth science, after analizing 5 kinds of earth science textbook of current using in high school, essential 19 items were selected. 5 of them were tested in test group and control group, then, the results were analized. 3. For the mathematice, the teaching elements of「Set」and「Flow chart」in mathematics (Ⅰ) were selected and structured. Detailed teaching objects were established and evaluation items were introduced.

부분편향 시료에 대한 기약 Tensor해석

孫基洙,金榮柱,姜昞燮,李壬洙 慶北大學校 1989 論文集 Vol.48 No.-

Depending on structure and electronic resonances the second-order non-linear susceptibility Χ^(2) is usually measured by second-harmonic generation. The macroscopic non-linear optical susceptibility Χ^(2) for a system of partially oriented molecules is written as the ensemble average of molecular hyperpolarizability tensor β. The orientational distribution of these molecules is described by a probability function expanded in Wigner matrices. It confirmed that Χ^(2) has seven non-vanishing conponents for a rotationally invariant system. For a molecule with C_2υ we compared average orientation angle of sum-frequency generation with of SHG, determined elements β_zzz β_xzx of the dominant molecular tensor components and caculated average orientation angle.

RAW264.7 세포에서 interferon-r 및 LPS에 의해 유도되는 NO생성에 미치는 TALT-35의 영향

박종일,박경석,김종석,박지훈,윤은진,송경섭,서강식,김훈,윤완희,박승길,임규,황병두 충남대학교 생물공학연구소 2006 생물공학연구지 Vol.12 No.-

TALP-35 purified from human term placenta is known to increase microtubule polymerization and stabilize the polymerized microtubule. To examine the effect of TALP-35 on immune system this study was performed. MTT assay was performed to investigate the effect of TALP-35 on the proliferation of RAW264.7 cells. TALP-35 dose dependently suppress the proliferation of RAW264.7 cells at high concentration (above 1 μM) in unstimulated cells, in case of 10 μM TALP-35 treated cells the suppression was 25% but in stimulated cells it was only 15%. Cosedimentation assay was carried out to investigate whether TALP-35 can bind to tubulin of RAW264.7, monocyte/macrophage lineage of mouse, and polymerize it. TALP-35 polymerize the tubulin of RAW264.7 cells and sedimented in dose-dependent manner. To investigate the effect of TALP-35 on the expression of iNOS protein western blotting was performed. The expression level of iNOS was decreased dose dependently in high concentration of TALP-35 treatment. To examine the activity of iNOS, secreted NO was determined by method based on Griess reaction. Interferon-γ and LPS-stimulated production of NO from RAW264.7 cells was decreased dose dependently above 0.1 μM concentration of TALP-35 and 50% is decreased at 10μM of it. This study shows TALP-35 can control cytokine induced-iNOS expression therefore it might control inflammatory diseases.

Sodium butyrate has context-dependent actions on dipeptidyl peptidase-4 and other metabolic parameters

Lee, Eun-Sol,Lee, Dong-Sung,Pandeya, Prakash Raj,Kim, Youn-Chul,Kang, Dae-Gil,Lee, Ho-Sub,Oh, Byung-Chul,Lee, Dae Ho The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.5

Sodium butyrate (SB) has various metabolic actions. However, its effect on dipeptidyl peptidase 4 (DPP-4) needs to be studied further. We aimed to evaluate the metabolic actions of SB, considering its physiologically relevant concentration. We evaluated the effect of SB on regulation of DPP-4 and its other metabolic actions, both in vitro (HepG2 cells and mouse mesangial cells) and in vivo (high fat diet [HFD]-induced obese mice). Ten-week HFD-induced obese C57BL/6J mice were subjected to SB treatment by adding SB to HFD which was maintained for an additional 16 weeks. In HepG2 cells, SB suppressed DPP-4 activity and expression at sub-molar concentrations, whereas it increased DPP-4 activity at a concentration of $1,000{\mu}M$. In HFD-induced obese mice, SB decreased blood glucose, serum levels of insulin and $IL-1{\beta}$, and DPP-4 activity, and suppressed the increase in body weight. On the contrary, various tissues including liver, kidney, and peripheral blood cells showed variable responses of DPP-4 to SB. Especially in the kidney, although DPP-4 activity was decreased by SB in HFD-induced obese mice, it caused an increase in mRNA expression of $TNF-{\alpha}$, IL-6, and $IL-1{\beta}$. The pro-inflammatory actions of SB in the kidney of HFD-induced obese mice were recapitulated by cultured mesangial cell experiments, in which SB stimulated the secretion of several cytokines from cells. Our results showed that SB has differential actions according to its treatment dose and the type of cells and tissues. Thus, further studies are required to evaluate its therapeutic relevance in metabolic diseases including diabetes and obesity.

Fe₄[Fe(CN)₆]₃가 코팅된 Mica 또는 TiO₂/Mica 적외선 반사용 청색안료 제조 및 이 도료의 차열 특성 평가

정하영,김대성,이현진,이승호,임형미,최병기,강광중,최진섭,Jung, Ha-Young,Kim, Dae Sung,Lee, Hyun-Jin,Lee, Seung-Ho,Lim, Hyung Mi,Choi, Byung-Ki,Kang, Kwang-Jung,Choi, Jin-Sub 한국재료학회 2013 한국재료학회지 Vol.23 No.12

$Fe_4[Fe(CN)_6]_3$ coated on a mica or $TiO_2$/mica surface as infrared reflective blue pigment was prepared by a hydrothermal method. $Fe_4[Fe(CN)_6]_3$, used as coloring agent, was uniformly coated on mica or $TiO_2$/mica under the optimized condition of a 1.2 : 1 weight ratio between iron(III) chloride hexahydrate and potassium ferrocyanidetrihydrate at the initial pH level of 4.5 at $70^{\circ}C$. The infrared (IR)-reflective pigments were characterized by SEM, Zeta-potenial, FT-IR, and UV-VIS NIR spectrophotometry. Especially the CIE color coordinate and total solar reflectance(TSR) properties of the pigments were investigated in relation to variation of the coating and coated substrate thicknesses. Isolation-heat paint was prepared with 20 wt% blue pigments fully dispersed in acryl-urethane resin and several additives to coat the film uniformly. The films were also measured with CIE color coordinate, TSR, and the surface temperature was recorded by an isolation-heat measuring system. The pigments and films of $Fe_4[Fe(CN)_6]_3$ coated on mica and $TiO_2$/mica showed high TSR values compared with the TSR value of $Fe_4[Fe(CN)_6]_3$ itself. According to the increase of TSR value, the property of isolation-heat is effective. To realize the optimal blue color, we applied the the pigment to $TiO_2$ coated mica(TM(b)) which has blueish interference color. The pigment of $Fe_4[Fe(CN)_6]_3$ coated on TM(b) shows a strong blue color compared with that of $Fe_4[Fe(CN)_6]_3$ coated on $TiO_2$/Mmca(TM(w)), which has a whitish interference color.

Effect on N Defect in Cu-doped III-nitride Semiconductors

Byung-Sub Kang,Jae-Kwang Lee,Yong-Sik Lim,Kie-Moon Song,Kwang-Pyo Chae 한국자기학회 2011 Journal of Magnetics Vol.16 No.4

We studied the effect on the electronic and magnetic properties of the N defect in clean and Cu-doped wurtzite III-nitrides by using the first-principles calculations. When it is doped two Cu atoms in the nearest neighboring sites, the system of AlN, GaN, or InN with the N vacancy is energetically more favorable than that without the N vacancy site. When the Cu concentration increases, the total magnetic moment of a supercell becomes small. The ferromagnetism of Cu atom is very low due to the weak 3d-3d coupling. It is noticeable that the spinexchange interaction between the Cu-3d and N defect states is important.

First-principle Study for Al<SUB>x</SUB>Ga<SUB>1-x</SUB>P and Mn-doped AlGaP₂ Electronic Properties

Byung-Sub Kang,Kie-Moon Song 한국자기학회 2015 Journal of Magnetics Vol.20 No.4

The ferromagnetic and electronic structure for the AlxGa1-xP and Mn-doped AlGaP₂ was studied by using the self-consistent full-potential linear muffin-tin orbital method. The lattice parameters of un-doped AlxGa1-xP (x= 0.25, 0.5, and 0.75) were optimized. The band-structure and the density of states of Mn-doped AlGaP₂ with or without the vacancy were investigated in detail. The P-3p states at the Fermi level dominate rather than the other states. Thus a strong interaction between the Mn-3d and P-3p states is formed. The ferromagnetic ordering of dopant Mn with high magnetic moment is induced due to the (Mn-3d)-(P-3p)-(Mn-3d) hybridization, which is attributed by the partially filled P-3p bands. The holes are mediated with keeping their 3d-characters, therefore the ferromagnetic state is stabilized by this double-exchange mechanism.

Effects of Nitrogen Defect on Magnetism of Cu-doped InN

Byung-Sub Kang,Kwang-Pyo Chae,Haeng-Ki Lee 한국자기학회 2013 Journal of Magnetics Vol.18 No.2

We investigate the electronic and magnetic properties in Cu-doped InN with the N vacancy (VN) from first principles calculations. There is the long-range ferromagnetic order between two Cu atoms, attributed to the hole-mediated double exchange through the strong p-d interaction between the Cu atom and neighboring N atom. The system of VN defect in Cu-doped InN has the lowest formation energy. Due to the hybridization between the Cu-3d and VN states, the spin-polarization on the Cu atoms in the InN lattice is reduced by VN defect. So, it shows a weak ferromagnetic behavior.

Ab initio Study for Electronic Property and Ferromagnetism of (Cu, N, or F)-codoped ZnO

Byung-Sub Kang,Kwang-Pyo Chae 한국자기학회 2012 Journal of Magnetics Vol.17 No.3

The effects on the ferromagnetism of the O or Zn defect in Cu-doped ZnO with the concentration of 2.77-8.33% have been investigated by the first-principles calculations. The Cu doping in ZnO was calculated to be akind of p-type ferromagnetic half-metals. When the Zn vacancy exists in Cu-doped ZnO, the Cu magnetic moment increases, while for the O vacancy it is reduced. It is noticeable that the ferromagnetic state was originated from the hybridized O(2p)-Cu(3d)-O(2p) chain formed through the p-d coupling. The carrier-mediated ferromagnetism by nitrogen or fluorine does not depend on their concentration.