Effect of H/Ar treatment on ZnO:B transparent conducting oxide for flexible a-Si:H/μc-Si:H photovoltaic modules under damp heat stress

Jeong, J.S.,Kim, Y.H.,Park, C.K.,Kim, H.D.,Choi, J. Pergamon Press 2016 Microelectronics and reliability Vol.64 No.-

<P>A flexible amorphous/microcrystalline Si:H (a-Si:H/mu c-Si:H) tandem-junction photovoltaic (PV) module was produced in which a thin film of ZnO:B grown by metalorganic chemical vapor deposition (MOCVD) served as the transparent conducting oxide (TCO). The Hall mobility of ZnO:B is degraded by damp heat, simulated here using the conditions of 85 degrees C at 85% relative humidity; this affects the series resistance and efficiency of the PV module. In this study, ZnO:B was treated by H/Ar plasma to reduce the degradation experienced under damp heat. The degradation time of the Hall mobility of ZnO:B, defined as the time necessary for the cell to reach the efficiency loss of -20%, was improved by similar to 54% by H/Ar treatment (ZnO:B center dot H/Ar). The mechanism behind this improvement was investigated by assessing the reactions of the ZnO:B and ZnO:B center dot H/Ar thin films to moisture. Related changes in the physical and chemical properties of ZnO:B and ZnO:B center dot H/Ar were analyzed by Xray photoelectron spectroscopy, secondary-ion mass spectroscopy, and ultraviolet photoelectron spectroscopy. The analyses showed that the concentration of OH- was high while those of Zn2+ and B3+ were low in the grain boundaries of the ZnO:B surface after exposure to humidity. After H/Ar treatment, the increase in OH- concentration in ZnO:B was reduced, and the decrease in the Zn2+ and B3+ concentrations was much smaller. The H/Ar plasma treatment of ZnO:B affected the surface reaction forming Zn(OH)(2), between the OH- and Zn2+ ions at the grain boundaries under damp heat. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Targeting the entry region of Hsp90's ATP binding pocket with a novel 6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl amide

Jeong, J.H.,Oh, Y.J.,Lho, Y.,Park, S.Y.,Liu, K.H.,Ha, E.,Seo, Y.H. S.E.C.T. [etc.] ; Elsevier Science Ltd 2016 European journal of medicinal chemistry Vol.124 No.-

The molecular chaperone Hsp90 plays an important role in cancer cell survival and proliferation by regulating the maturation and stabilization of numerous oncogenic proteins. Due to its potential to simultaneously disable multiple signaling pathways, Hsp90 has emerged as an attractive therapeutic target for cancer treatment. In this study, the design, synthesis, and biological evaluation of a series of Hsp90 inhibitors are described. Among the synthetic compounds, 6,7-dihydrothieno [3,2-c]pyridin-5(4H)-yl amide 19 exhibits a remarkable binding affinity to the N-terminus of Hsp90 in a fluorescence polarization (FP) binding assay (IC<SUB>50</SUB> = 50.3 nM). Furthermore, it effectively inhibits the proliferation of H1975 non-small cell lung cancer (NSCLC) and Skbr3 breast cancer cell lines with GI<SUB>50</SUB> values of 0.31 μM and 0.11 μM, respectively. Compound 19 induces the degradation of the Hsp90 client proteins including EGFR, Her2, Met, c-Raf, and Akt, and consequently promotes apoptotic cancer cell death. Compound 19 also inhibits the growth of H1975 xenografts in NOD-scid IL2R gamma<SUP>null</SUP> mice without any apparent body-weight loss. The immunohistologic evaluation indicates that compound 19 decreases the expression of Akt in xenograft tumor tissue via an inhibition of the Hsp90 chaperon function. Additionally, the cytochrome P450 assay indicates that compound 19 has no effect on the activities of five major P450 isoforms (IC<SUB>50</SUB> > 50 μM for 1A2, 2C9, 2C19, 2D6, and 3A), suggesting that clinical interactions between compound 19 and the substrate drugs of the five major P450 isoforms are not expected. Overall, compound 19 represents a new class of Hsp90 inhibitor with its 6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl-amide structure, and it has the therapeutic potential to overcome drug resistance in cancer chemotherapy.

광전도체의 CdS 단결정 성장과 물리적 특성

정태수,유평열,신영진,신현길,김택성,정철훈,이훈,신영신,홍광준,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

승화방법으로 광전도체의 CdS 단결정을 성장하였고 외삽법으로 구한 a_o와 c_o 의 격자상수 값은 각각 4.1318Å과 6.7122Å임을 알았다. Hall 측정값으로 부터 상온에서의 CdS 단결정의 운반자 농도와 이동도는 각각∼10^23m^-3과 2.93×10 exp (-2)㎡/V sec 이였으며 온도에 따른 이동도 변화는 33 K에서 150 K까지는 T^1/2 에 따라 증가하는 경향이 있고 180 K 에서 상온까지는 T^-2에 따라 감소한 경향이 나타났다. 광전류 측정으로 부터 나타난 단파장대의 봉우리는 진성전이에 기인하는 봉우리였으며 이 봉우리의 에너지값은 CdS 광전도체에 에너지 밴드 갭과 동일한 값을 나타냄을 알았다. A CdS single crystal was grown by using sublimation method. Lattice constants, a_o and c_o , obtained by using extrapolation were 4.1318 Å and 6.7122 Å, respectively. The carrier density was∼10^23m^-3 and the mobility was 2.93×10 exp (-2)㎡/V-sec from measured Hall data at room temperature. The mobility has a increasing tendency in proportion to T^1/2 from 33 K to 150 K and a decreasing tendency in proportion to T^-2 from 180 K to room temperature. The short wavelength band peak measured from photocurrent was due to intrinsic transition, and the energy value of this peak was equal to the energy band gap of CdS photoconductor.

Ex situ catalytic upgrading of lignocellulosic biomass components over vanadium contained H-MCM-41 catalysts

Kim, B.S.,Jeong, C.S.,Kim, J.M.,Park, S.B.,Park, S.H.,Jeon, J.K.,Jung, S.C.,Kim, S.C.,Park, Y.K. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.265 No.-

<P>H-V-MCM-41 catalysts containing 5, 10, and 30 wt% of vanadium were synthesized and applied to the ex situ catalytic pyrolysis (CP) of three polymeric components of lignocellulosic biomass for the first time. Characterization of the catalysts was performed using N-2 adsorption-desorption, XRD, FT-IR, and NH3-TPD. The results of XRD analysis showed that 5 wt% and 10 wt% H-V-MCM-41 catalysts maintained the mesoporous structure, whereas the mesoporous structure was destroyed in 30 wt% H-V-MCM-41 with considerable amount of small V2O5 crystalline outside the framework. NH3-TPD showed that H-V-MCM-41 has mostly weak acid sites and that 10 wt% H-V-MCM-41 had the largest quantity of acid sites due to framework vanadium. In the case of CP of cellulose using Py-GC/MS, 10 wt% H-V-MCM-41 showed the highest catalytic activity for the production of valuable furanic compounds such as furfural because of the enhanced deoxygenation over the acid sites formed on framework vanadium. In the case of CP of xylan as well, 10 wt% H-V-MCM-41 led to the largest yield of mono-aromatics. The production of acetic acid was also promoted by H-V-MCM-41 catalysts. The CP of lignin over H-V-MCM-41 catalysts promoted substantially the production of important feedstock chemicals for the petrochemical industry: phenolics and mono-aromatics. (C) 2015 Elsevier B.V. All rights reserved.</P>

Surveillance of avian influenza virus in wild bird fecal samples from South Korea, 2003-2008.

Kang, H M,Jeong, O M,Kim, M C,Kwon, J S,Paek, M R,Choi, J G,Lee, E K,Kim, Y J,Kwon, J H,Lee, Y J [Wildlife Disease Association] 2010 JOURNAL OF WILDLIFE DISEASES Vol.46 No.3

<P>We analyzed the results from nationwide surveillance of avian influenza (AI) from birds in South Korea's major wild bird habitats and the demilitarized zone of South Korea, 2003-2008. Of 28,214 fecal samples analyzed, 225 yielded influenza viruses, for a prevalence of 0.8%. Hemagglutinin (HA) subtypes H1-H12 and all nine neuraminidase (NA) subtypes were detected. The dominant HA subtypes were H6, H1, and H4, and the most common NA subtypes were N2, N1, and N6. Among the 38 HA/NA subtype combinations, the most common were H4N6, H6N1, and H5N2. Thirty-seven low-pathogenic AI (LPAI) viruses of the H5 and H7 subtype were detected. Among them, we identified bird species for 16 H5- and H7-positive fecal samples using a DNA bar-coding system instituted in 2007; all birds were identified as Anseriformes. The HA gene of the H5 wild bird isolates belonged to the Eurasian avian lineage, and could be clearly distinguished from the sublineage H5N1 highly pathogenic AI (HPAI) of the Eurasian and American avian lineages. Whereas H7 LPAI viruses did not group as a separate sublineage with H7 HPAI viruses, H7 isolates were closely related with the Eurasian avian lineage.</P>

Genetic and phylogenetic characterizations of a novel genotype of highly pathogenic avian influenza (HPAI) H5N8 viruses in 2016/2017 in South Korea

Kim, Y.I.,Park, S.J.,Kwon, H.I.,Kim, E.H.,Si, Y.J.,Jeong, J.H.,Lee, I.W.,Nguyen, H.D.,Kwon, J.J.,Choi, W.S.,Song, M.S.,Kim, C.J.,Choi, Y.K. Elsevier Science 2017 INFECTION GENETICS AND EVOLUTION Vol.53 No.-

<P>During the outbreaks of highly pathogenic avian influenza (HPAI) H5N6 viruses in 2016 in South Korea, novel H5N8 viruses were also isolated from migratory birds. Phylogenetic analysis revealed that the HA gene of these H5N8 viruses belonged to clade 2.3.4.4, similarly to recent H5Nx viruses, and originated from A/Brk/Korea/Gochang1/14(H5N8), a minor lineage of H5N8 that appeared in 2014 and then disappeared. At least four reassortment events occurred with different subtypes (H5N8, H7N7, H3N8 and H10N7) and a chicken challenge study revealed that they were classified as HPAI viruses according to OIE criteria. (C) 2017 Elsevier B.V. All rights reserved.</P>

희토류 금속을 첨가한 적철광의 자기상 전이

한경훈,신경호,김정기,정재윤 漢陽大學校 自然科學硏究所 2000 自然科學論文集 Vol.19 No.-

다결정시료(Fe₂O₃)1-x(Eu₂O₃)x (x=0.04와 0.06)계의 자기상 전이를 연구하기 위해 상온에서의 X선 회절, 액체질소온도에서 상온에 이르는 온도구간에서의 Mossbauer 분광과 약 8K에서 300K의 온도구간에서의 자기능률 측정방법을 사용하였다. X선 회절은 본 연구의 다결정시료가 a-Fe₂O₃와 동일한 rhombohedral결정구조를 가짐을 보인다. X선 회절선의 결과를 이용하여 비선형최소자승법을 써서 각 시료의 격자상수값을 구하였다. Mossbauer 분광결과는 자기상 전이가 255K<T<265K 온도 영역에서 일어남을 보인다. 온도영역 T<255K에서의 초미세 자기장의 온도 의존성에 반강자성 spinwave이론이 잘 적용됨을 보인다. 온도에 따른 magnetization의 변화로 자기상전이 온도를 관찰하였으며, 이 결과는 Mossbauer 분광 결과와 잘 일치 하였다. 상온에서의 hysteresis 곡선은 Eu농도가 증가함에 따라서 보자력이 증가하지만 자화와 잔류자화는 감소했음을 알 수 있었다. A study of magnetic transition for the polycrystalline (Fe₂O₃)1-x(Eu₂O₃)x (x=0.04 and 0.06) has been performed by the methods of X-ray diffraction at room temperature, Mossbauer spectroscopy within the temperature range from liquid nitrogen to room temperature, and a measurement of magnetic moment within temperature range of 8K∼300K. X-ray diffraction shows that the samples are in the same rhombohedral crystal structure as that of a-Fe₂O₃. The lattice parameter of the samples has been determined from X-ray diffraction patterns using computer with a progam of nonlinear square-fit. The Mossbauer results tell us that the magnetic transition of the samples occurs in the temperature region of 255K<T<265K. The temperature dependence of magnetic hyperfine field of the samples is in good agreement with a spin-wave theory for a antiferromagnetic phase within the temperature range from liquid nitrogen to 255K. The magnetic phase transition was observed by a temperature dependence of magnetization and the result was in good agreement with that of Mossbauer. Magnetic hysteresis curves indicated that the values of coercivity increase but that of magnetization and remanence of the samples decrease as increasing the concentration of Eu.

CBD 방법에 의한 CdS 박막의 성장과 광전도 특성

황광준,이상열,유상하,서상석,문종대,신영진,정태수,신현길,김택성,송정훈,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

Chemical bath deposition 방법으로 다결정 CdS 박막을 세라믹 기판 위에 성장시킨 다음 온도를 변화시켜 열처리하고 X-선 회절무늬를 측정하여 결정구조를 밝혔다. 550℃로 열처리한 시료의 경우 X-선 회절무늬로 부터 외삽법에 의해 a_。와 c_。는 각각 4.1364 Å과 6.7129 Å인 육방정계임을 알았다. 이 때 낱알크기는 약 0.35㎛이었다. Van der Pauw 방법으로 Hall 효과를 측정하여 운반자 농도와 이동도의 온도의존성을 연구하였다. 이동도는 33 K 에서 150 K 까지는 압전산란에 의하여, 150 K 에서 293 K 까지는 극성광학산란에 의하여 감소하는 경향이 나타냈다. 광전도 셀의 특성으로 스텍트럼 응답, 감도(γ), 최대허용소비전력 및 응답 시간을 측정하였다. Polycrystalline CdS thin films were grown on creamic substrate using a chemical bath deposition method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdS polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdS samples annealed in N_2 gas at 550℃ it was found hexagonal structure whose lattice constants a_o and c_o were 4.1364 Å and 6.7120Å, respectively. Its grain size was about 0.35 ㎛. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 150K and by polar optical scattering at temperature range of 150K and 293K. We measured also spectral response, sensitivity (γ), maximum allowable power dissipation and response time on these samples.

Chemical Bath Deposition 방법으로 제작한 CdSe 박막의 특성

홍광준,이상열,유상하,서상석,문종대,신영진,정태수,신현길,김택성,송정훈,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

Chemical bath deposition 방법으로 다결정 CdSe 박막을 세라믹 기판 위에 성장시킨 다음 온도를 변화시켜 열처리하고 X-선 회절무늬를 측정하여 결정구조를 밝혔다. 450℃로 열처리한 시료가 X-선 회절무늬로 부터 외삽법에 의해 a_o와 c_o 는 각각 4.302 Å과 7.014 Å인 육방정계임을 알았다. 이 때 낱알크기는 약 0.3㎛이었다. Van der Pauw 방법으로 Hall 효과를 측정하여 운반자 농도와 이동도의 온도의존성을 연구하였다. 이동도는 33 K 에서 200 K 까지는 압전산란에 의하여, 200 k 에서 293 K 까지는 극성광학산란에 의하여 감소하는 경향이 나타냈다. 광전도 셀의 특성으로 스텍트럼 응답, 감도(γ), 최대허용소비전력 및 응답 시간을 측정하였다. Polycrystalline CdSe thin films were grown on creamic substrate using a chemical bath deposition (CBD) method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in N_2 gas at 450℃ it was found hexagonal structure whose lattice parameters a_o and c_o were 4.302 Å and 7.014 Å, respectively. It grain size was about 0.3 ㎛. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33 K and 200 K, and by polar optical potical scattering at temperature range of 200 K and 293 K. We measured also spectral response, sensitivily (γ), maximum allowable power dissipation and response time on these samples.

HWE(Hot Wall Epitaxy)에 의한 ZnIn_2S_4 박막 성장과 광전도 특성

홍광준,이관교,정준우,정경아,방진주,장현규,문종대,김혜숙 조선대학교 기초과학연구소 1999 自然科學硏究 Vol.22 No.1

HWE 방법에 의해 ZnIn_2S_4 박막을 Si(00) 기판 위에 성장시켰다. 증발원과 기판의 온도를 각각 610℃, 450℃로 하여 성장시킨 ZnIn_2S_4 박막의 이중 결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)값이 245 arcsec로 가장 작았다. Van der Pauw 방법으로 Hall 효과를 측정하여 운반자농도의 1n n 대 1/T에서 구한 활성화에너지는 0.17eV로 측정되었다. Hall 이동도의 온도 의존성은 30K에서 100K까지는 불순물산란에 기인하고, 100K에서 293K까지는 격자산란에 기인한것으로 고찰되었다. 광전도셀의 특성으로 spectral response, 최대 허용소비전력(MAPD), 광전류와 암전류(pc/dc)의 비 및 응답시간을 측정하였다. S 증기분위기에서 열처리한 광전도 셀의 경우, 감도(??)는 0.99, pc/dc은 1.37x10^7, 그리고 최대 허용소비전력(MAPD)은 336mW, 오름시간(rise time)은 9ms, 내림시간(decay time)은 9.8ms로 가장 좋은 광전도 특성을 얻었다. The ZnIn_2S_4 thin films were grown on the Si(100) wafers by a hot wall epitaxy method(HWE). The source and substrate temperature are 610℃ and 450℃ respectively. The crystalline structure of epilayers was investigated by double crystal X-ray diffraction(DCXD). Hall effect on the sample was measured by the van der Pauw method and studied on the carrier density and mobility dependence on temperature. From Hall data, the mobility was increased in the temperature range 30K to 100K by impurity scattering and decreased in the temperature range 100K to 293K by the lattice scattering. In order to explore the applicability as a photoconductive cell, we measured the sensitivity(??), the ratio of photocurrent to darkcurrent(pc/dc), maximum allowable power dissipation(MAPD), spectral response and response time. The results indicated that the photoconductive characteristic were the best for the samples annealed in S vapor compare with in Zn, In, air and vacuum vapour. Then we obtained the sensitivity of 0.99, the value of pc/dc of 1.37x10^7, the MAPD of 336mW, and the rise and decay time of 9ms and 9.8ms, respectively.