Y/Gd-free yellow Lu₃Al₅O₁₂:Ce³⁺ phosphor for white LEDs

Park, K.,Kim, T.,Yu, Y.,Seo, K.,Kim, J. Elsevier [etc.] 2016 Journal of luminescence Vol.173 No.-

<P>Solid solubility limit of Ce3+ ions into Lu-based garnet, Lu3(1-x)Ce3xAl5O12, was determined as below 6.7 mol% (3x < 0.2 mol) through Raman spectra and X-ray diffraction patterns. Above the solid solubility limit (3x >= 0.2 mol), Lu3((1-x))Ce(3x)Al(5)O(12) phosphors showed the significant redshift to the yellow spectral region without Y3+ and Gd3+ ions. The redshift was explained in terms of the local compressive strain at the Ce3+ sites. The optimized sample (3x=0.4 mol) had a dominant emission wavelength of 548 nm, color coordinate of CIEx=0.421, CIEy=0.548, quantum efficiency of 80%, absorbance of 91%, lumen maintenance of 90% and high color stability at 473 K under 450 nm excitation wavelength, suggesting substitutability for the commercial yellow (Y, Gd)(3)(Al, Ga)(5)O-12:Ce3+ phosphor. The measured decay times at higher Ce3+ concentration are significantly shortened at higher temperature than that of those at lower Ce3+ concentration. The yellow Lu2.6Ce0.4Al5O12 and a commercial red (Sr, Ca)AlSiN3:Eu2+ phosphor were applied to the pc-WLED, it gave an excellent luminous efficiency (138 lm/W) with a slightly lower color rendering index (Ra =76.4) under correlated color temperature of 6500 K compared to those of the (Y, Gd)(3)(Al, Ga)(5)O-12:Ce3+-based one (136 lm/W, Ra =78.7). Especially, the quantities of the used phosphors were significantly decreased by 20% for the yellow LuAG:Ce and by 40% for the red (Sr, Ca)AlSiN3:Eu2+. Thus, the Y/Gd-free pure LuAG:Ce yellow phosphors can be used as alternative to the commercial yellow YAG:Ce phosphor. (C) 2016 Elsevier B.V. All rights reserved.</P>

고온기 초지의 예취관리에 관한 연구 6 . 고온기간중 예취높이와 질소 및 칼리추비가 혼파초지의 식생과 수량 및 목초품질에 미치는 영향

서성(S . Seo),조무환(M . H . Jo),박문수(M . S . Park),이종경(J . K . Lee),한영춘(Y . C . Han) 한국축산학회 1988 한국축산학회지 Vol.30 No.8

A field experiment was carried out to determine the effects of cutting height at the third cut and application of N and K₂O after cutting during mid-summer season on the soil temperature, plant height, grass coverage, percentages of grass and legume, yield and grass quality in orchardgrass dominated pasture. With three cutting heights (3, 6 and 9㎝) and 4 fertilizer levels (0, N 50㎏, K₂O 50㎏, and N 50㎏ + K₂O 50㎏ ㏊^(-1)), present experiment was conducted at Livestock Experiment Station, Suwon in 1987. 1. The soil temperature after the third cut was rapidly elevated, and lower value was observed with 9㎝ of cutting height through the regrowth period. Plant height after cutting was remarkably increased with higher stubble height regardless of fertilizer levels. 2. The grass coverage and percentage of grass were increased as stubble height was high, while the influence of fertilizer on those was very little. Application of N and K₂O with lower stubble height significantly increased the percentage of bareland. 3. The yield at the third cut was decreased with higher height. But the regrowth yield was significantly increased as the cutting height was increased regardless of fertilizer levels. Regrowth yield was great at N 50㎏ + K₂O 50㎏ $gt; 0 $gt; K₂O 50㎏, N 50㎏, in that order. However, there were not significantly different on regrowth yield among fertilizer treatment. 4. The contents of crude protein, crude fat, crude ash, P, K and Ca were decreased as stubble height was high, and that of crude fiber was increased at 9 ㎝ cutting height. Also the influence of N and K₂O fertilizer on grass quality was little.

TMEM175 Is an Organelle K⁺ Channel Regulating Lysosomal Function

Cang, C.,Aranda, K.,Seo, Y.j.,Gasnier, B.,Ren, D. Cell Press ; MIT Press 2015 Cell Vol.162 No.5

Potassium is the most abundant ion to face both plasma and organelle membranes. Extensive research over the past seven decades has characterized how K<SUP>+</SUP> permeates the plasma membrane to control fundamental processes such as secretion, neuronal communication, and heartbeat. However, how K<SUP>+</SUP> permeates organelles such as lysosomes and endosomes is unknown. Here, we directly recorded organelle K<SUP>+</SUP> conductance and discovered a major K<SUP>+</SUP>-selective channel K<SUB>EL</SUB> on endosomes and lysosomes. K<SUB>EL</SUB> is formed by TMEM175, a protein with unknown function. Unlike any of the ~80 plasma membrane K<SUP>+</SUP> channels, TMEM175 has two repeats of 6-transmembrane-spanning segments and has no GYG K<SUP>+</SUP> channel sequence signature-containing, pore-forming P loop. Lysosomes lacking TMEM175 exhibit no K<SUP>+</SUP> conductance, have a markedly depolarized ΔΨ and little sensitivity to changes in [K<SUP>+</SUP>], and have compromised luminal pH stability and abnormal fusion with autophagosomes during autophagy. Thus, TMEM175 comprises a K<SUP>+</SUP> channel that underlies the molecular mechanism of lysosomal K<SUP>+</SUP> permeability.

A Case of Letterer-Siwe Disease

Lee, Y. J 大韓皮膚科學會 1995 大韓皮膚科學會誌 Vol.33 No.5

K-band frequency-selective limiter using an injection locked oscillator for blocker cancellation

Choi, K.,Jung, J.,Park, H.,Seo, T.,Jeong, J.,Kwon, Y. Institution of Electrical Engineers 2018 Electronics letters Vol.54 No.7

<P>A frequency-selective limiter (FSL) using an injection locked oscillator (ILO) is proposed for a blocker cancellation, which employs an ILO in the feedforward path as a high-Q notch filter to select and amplify the blocker from the input signal. The ILO also functions as a phase shifter providing a proper phase delay so that two blockers in the feedforward and thru paths cancel each other out in the combining node. The proposed FSL is fabricated in a commercial 0.15 mu m GaAs pHEMT process with a maximum blocker suppression of 27 dB in the 50 MHz spacing two-tone measurement at the K-band. Thus, it provides a blocker suppression higher than 20 dB over the 250 MHz blocker bandwidth.</P>

Microstructure and piezoelectric properties of (Na_0.5K_0.5)NbO₃ lead-free piezoelectric ceramics with V₂O₅ addition

Seo, I.-T.,Park, H.-Y.,Dung, N.V.,Choi, M.-K.,Nahm, S.,Lee, H.-G.,Choi, B.-H. IEEE 2009 and Frequency Control Vol.56 No.11

<P>Various amounts of Nb<SUB>2</SUB>O<SUB>5</SUB> in the (Na<SUB>0.5</SUB>K<SUB>0.5</SUB>) NbO<SUB>3</SUB> (NKN) ceramic were replaced by V<SUB>2</SUB>O<SUB>5</SUB> to decrease its sintering temperature to below 950°C. A small V<SUB>2</SUB>O<SUB>5</SUB> content resulted in a dense microstructure with an increased grain size for the specimen sintered at 900°C due to the presence of a liquid phase. When V<SUB>2</SUB>O<SUB>5</SUB> was added to the NKN ceramics, their orthorhombic-to-tetragonal transition temperature increased from 178°C to around 200°C. However, their Curie temperature decreased from 402°C to around 330°C. The k<SUB>p</SUB>, <SUB>ε3</SUB> <SUP>T</SUP>/<SUB>ε0</SUB>, and Q<SUB>m</SUB> values increased with V<SUB>2</SUB>O<SUB>5</SUB> addition, probably due to the increased density and poling state, which was identified by the phase angle. The specimen with x = 0.05, sintered at 900°C for 8 h, exhibited the following piezoelectric properties: k<SUB>p</SUB> = 0.32, <SUB>ε3</SUB> <SUP>T</SUP>/<SUB>ε0</SUB> = 245, d<SUB>33</SUB> = 120 (pC/N), and Q<SUB>m</SUB> = 232.</P>

망간계 산화물 La₁??Ce??MnO₃(x=0.2, 0.3, 0.4)의 전기,자기 및 열적 특성 연구

서금영,이보화 한국외국어대학교 외국학종합연구센터 부설 기초과학연구소 1999 기초과학연구 Vol.9 No.-

망간계 산화물 La₁???Ce??MnO₃(x=0.2, 0.3, 0.4)의 전기, 자기 및 열적 특성에 관한 연구를 X-선 회절, 전기저항, 자화율, 비열 및 광음향 신호 측정을 통하여 수행하였다. LaMnO₃의La대신 Ce 이온의 치환은 강자성 정렬의 발생과 더불어서 금속-절연체의 전이를 일으킨다. 강자성 전이는 x=0.2, 0.3, 0.4에 대햐여 각각 249K, 259K, 249K에서 일어난다. x=0.3의 경우, 온도에 따른 비저항 곡선에서 열적 이력현상은 관찰할 수 없었으며, 광음향 신호의 크기의 변화 또한 온도를 올리거나 내리는 경우 같은 온도에서 일어났다. 이것은 상전이가 전이온도에서 잠열이 존재하지 않는 2차 상전이임을 의미한다. Resencwaig와 Gersho의 이론을 사용하여 열전도도의 상대적인 값을 광음향 신호에서 얻을 수 있었다. Electric, magnetic, and therma] properties for La₁???Ce??MnO₃ (x=0.2, 0.3, 0.4) were investigated by means of X-ray diffraction, electrical resistivity, magnetization, specific heat, and photoacoustic signal measurements. The substitution of La by Ce in LaMnO₃ induces a metal-insulator transition accompanied by the occurrence of ferromagnetic ordering. The ferromagnetic transition temperatures are 249K, 259K, 249K for x=0.2, 0.3, 0.4, respectively. For x=0.3, there is no observable thermal hysteresis in resistivity measurement, and the change of photoacoustic signal amplitude arises at the same temperature in both cases with decreasing and increasing temperatures. This implies that the phase transition can be regarded as a second-order phase transition with no latent heat at transition temperature. Using Rosencwaig and Gersho's theory, the relative value of thermal conductivity can be obtained from the photoacoustic signal.

A Design of Transferable Sample Holder for Resistive Heating and Conductive Cooling

Seo, J.M.,Kim, K.J.,Ihm, S.,Koo, S.J.,Park, Ch.,Kim, Y.K. 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

통전가열, 접촉냉각, 전기적 bias 및 시료 교환을 자유로이 할 수 있는 다기능의 새롭고 간단한 시료 고정장치를 저온 및 초고진공 상태에서 기체와 여러 방향의 시료표면 사이의 상호작용을 연구하기 위하여 고안하였다. 이 장치로써 2분 이내에 기판의 온도를 1600 K에서 20 K로 2분 이내에 냉각시킬 수 있었다. 그러므로 청결한 표면위에 수소나 He이나 Ne을 제외하고는 대부분의 기체를 흡착시킬 수 있게 되었다. 이러한 장치는 표면에서의 상변화, 기체와 표면의 화학반응의 연구에 중요하게 활용될 수 있다. A simple and novel sample-holder which has multi-functions of resistive heating, conductive cooling, electrical biasing and sample exchanging has been designed in order to inverstigate gas-surface interations for various surface direction under ultrahigh vacuum and low temperature. It has been proved that the wafer can be cooled from 1600 K to 20 K within two minutes. Therefore the controlled adsorption of most gases, except H, He and Ne, were possible on the clean surfaces. The design has substantial applocations in areas like surface phase transitions and gas-surface chemical reactions.

Lattice Dynamic Characteristics Observed by X-ray Diffraction and Nuclear Resonance Under the Influence of the Iso/Nonisomorphic Impurities in K₂SnCl_(6) Near the Phase Transition Temperature

Kim, Y.H.,Cha, Y.J.,Kang, J.P.,Hong, S.D.,Seo, Y.M.,Song, S.K. 명지대학교 자연과학연구소 2006 자연과학논문집 Vol.25 No.-

Lattice dynamics in the iso- and nonisomorphically impurity doped potassium-hexachloro-stannate (K₂SnCl_(6)) was studied using Nuclear Quadrupole Resonance (NQR). The results revealed a systematic trends of impurity effects in each case that are contrasting to one the other. In the case of the isomorphic system (K₂Sn_(1-x)Re_(x)Cl_(6)) their overall features are static while in the nonisomrphic system (K₂SnCl_(6):Al^(3+)) they are rather indirect and dynamic. The nuclear quadrupole resonance was supplemented by the X-ray diffraction to identify the static bulk structure of the crystal. In the nonisomorphic system the resonance spectra indicate the onset of the pre-transitional local structure above the phase transition temperature that seems to be facilitated by the formation of the ligand-deficient octahedra (AlCl_(5)^(2-)) via the enhanced activity of the hindered rotation.

Left atrial isomerism에 동반된 양대혈관 좌심실 기시, 폐동맥협착 및 정맥이상 환류증의 수술1예 보고

김원곤,김삼현,박영관,김남수,이흥재,최영희,서연림,서정욱 世宗醫學硏究所 1986 世宗醫學 Vol.3 No.1