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Investigation on substrate effect on physical characteristics of CuO- sprayed thin films suitable for photovoltaic application: Ag/ZnO:Sn (n)/CuO (p)/SnO2:f

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MATERIALS TECHNOLOGY 2022年第6期37卷 381-396页

作者： Ajili, Mejda Dabbabi, Samar Bouarissa, Nadir Kamoun, Najoua Turki Univ Tunis El Manar Fac Sci Tunis Lab Phys Mat Condensee Tunis Tunisia Univ Msila Lab Phys Mat & Ses Applicat Msila Algeria

In this paper to compare the growth and optoelectronic properties of copper oxide (CuO) materials suitable for advanced application, CuO layers were synthesized on glass and SnO2:f). The X-ray diffraction analysis showed that CuO nanoparticles were formed in pure monoclinic structure where crystallite size decreases from 37.39 to 33.44 nm when the substrate changed, respectively, from glass to SnO2:f/glass. This crystallite size reduction was related to the energy band gap (Eg) enlargement from 1.455 to 1.525 eV due to the quantum confinement effect. Eg values were almost equal to the theoretical one for converting solar energy into electrical energy and CuO may be used as an absorber material in photovoltaic devices. Electrical characteristics were studied using the impedance spectroscopy technique at room temperature and confirmed by the Hall Effect measurements. CuO/SnO2:f/glass thin films have best electrical parameters and consequently the Ag/ZnO:Sn(n)/CuO(p)/SnO2:f photocell was elaborated and its J-V characteristics were analyzed.

关键词： CuO Sno(2) f ZnO Sn spray pyrolysis thin film substrate photocell

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Rapid long-period grating formation in hydrogen-loaded fibre with 157 nm f₂-laser radiation

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ELECTRONICS LETTERS 2000年第24期36卷 2000-2001页

作者： Chen, KP Herman, PR Tam, R Zhang, J Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada Photon Res Ontario Toronto ON M5S 1A7 Canada

Long-period gratings were fabricated in hydrogen-loaded telecommunication fibre using 157nm f-2-laser radiation. A >20dB attenuation peak at 1590nm was induced with only 5.0J/cm(2) accumulated fluence, a value >... 详细信息

关键词： Krf-laser irradiation telecommunication fibre accumulated fluence H fluence requirements optical fibre communication optical fibre fabrication laser materials processing optical fibre losses hydrogen 248 nm f Krf -loaded fibre fabrication 157 nm long-period grating formation 1590 nm -laser radiation long-period gratings diffraction gratings attenuation peak

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A chemical dry etching of Si and SiO₂ substrates by f atoms in a discharge flow

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JAPANESE JOURNAL Of APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 1997年第11期36卷 6922-6926页

作者： Tsuji, M Nishimura, Y Kyushu Univ Inst Adv Mat Study Fukuoka 816 Japan

f atoms were generated by a low power microwave discharge of various Ar/Cf4 mixtures in a fast discharge how. They were used for Si and SiO2 etching at room temperature. The variations of the relative concentration of f as functions of various etching parameters were monitored by observing CH(A(2) Delta-X-2 Pi(r)) emission resulting from the Ar(P-3(0,2))/CH3 reaction. The emission spectra of Ar/Cf4 mixtures in the microwave discharge indicated that Cf4 was decomposed into C and f atoms in the discharge region because of the lack of emissions from Cf*, Cf2*, and Cf3*. The etching rates of Si and SiO2 were about 700 and 70 Angstrom/min, respectively, at a microwave power of 100 W, an Ar how rate of 3000 seem, a Cf4 flow rate of 250 seem, a total pressure of 0.23 Torr and a distance between the center of discharge and the substrate of 12 cm.

关键词： dry etching discharge flow microwave discharge emission spectrum f Si SiO2

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Major metabolite of f₂-isoprostane in urine may be a more sensitive biomarker of oxidative stress than isoprostane itself

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AMERICAN JOURNAL Of CLINICAL NUTRITION 2012年第2期96卷 405-414页

作者： Dorjgochoo, Tsogzolmaa Gao, Yu-Tang Chow, Wong-Ho Shu, Xiao-ou Yang, Gong Cai, Qiuyin Rothman, Nathaniel Cai, Hui Li, Honglan Deng, Xinying franke, Adrian Roberts, L. Jackson Milne, Ginger Zheng, Wei Dai, Qi Vanderbilt Univ Sch Med Div Epidemiol Nashville TN 37212 USA Vanderbilt Univ Sch Med Div Clin Pharmacol Nashville TN 37212 USA Vanderbilt Univ Sch Med Dept Pharmacol Nashville TN 37212 USA NCI Div Canc Epidemiol & Genet NIH Dept Hlth & Human Serv Bethesda MD 20892 USA Shanghai Canc Inst Dept Epidemiol Shanghai Peoples R China Univ Hawaii Canc Res Ctr Hawaii Honolulu HI 96813 USA

Background: There is limited literature on the contributors to isoprostane metabolite 2,3-dinor-5,6-dihydro-15-f-2t-isoprostane (15-f-2t-IsoP-M) compared with f-2-isoprostanes (f-2-IsoPs) as an oxidative stress biomarker. Objective: The objective of this study was to investigate whether plasma concentrations of antioxidants, urinary excretion rates of polyphenols, and antioxidants in food and dietary supplements are attributable to both urinary f-2-IsoP and 15-f-2t-IsoP-M concentrations. Design: Dietary intake information and blood and urine samples were obtained from 845 healthy middle-aged and elderly female participants of the Shanghai Women's Health Study. Urinary isoprostanes (f-2-IsoPs and 15-f-2t-IsoP-M) were measured and adjusted for creatinine concentrations. Results: Urinary 15-f-2t-IsoP-M and f-2-IsoP concentrations were lower in subjects who used a multivitamin. Lower f-2-IsoP concentrations were observed in ginseng users, whereas lower concentrations of 15-f-2t-IsoP-M were shown in subjects who used a vitamin E supplement. Plasma concentrations of several antioxidants (ie, beta-carotenes, both trans and cis beta-carotenes, lycopene other than trans, 5-cis and 7-cis isomers, cis anhydrolutein, and cis beta-cryptoxanthin) were inversely associated with 15-f-2t-IsoP-M but not with f-2-IsoPs, whereas beta-, gamma-, and delta-tocopherols were positively associated with 15-f-2t-IsoP-M but not with f-2-IsoPs. Urinary polyphenol quercetin was positively associated with both f-2-IsoPs and 15-f-2t-IsoP-M. Conclusion: The results suggest that the f-2-IsoP major metabolite 15-f-2t-IsoP-M may be a more sensitive marker of endogenous oxidative stress status than are f-2-IsoPs in the assessment of effects of antioxidants on age-related diseases. Am J Clin Nutr 2012;96:405-14.

关键词： EGC epigallocatechin f 2 -IsoP f 2 -isoprostane GC/NICI MS gas chromatography/negative-ion chemical ionization mass spectrometry 15-f 2t -IsoP-M 2,3-dinor-5,6-dihydro-15-f 2t -isoprostane

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GREEN ALGAL CYTOCHROME B6-f-COMPLEXES - ISOLATION AND CHARACTERIZATION fROM DUNALIELLA-SALINE, CHLAMYDOMONAS-REINHARDTII AND SCENEDESMUS-OBLIQUUS

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BIOCHIMICA ET BIOPHYSICA ACTA 1988年第2期935卷 115-122页

作者： WYNN, RM BERTSCH, J BRUCE, BD MALKIN, R UNIV CALIF BERKELEY DIV MOLEC PLANT BIOL 313 HILGARD HALL BERKELEY CA 94720 USA

Cytochrome b6-f complexes have been isolated from Chlamydomonas reinhardtii, Dunaliella salina, and Scenesdesmus obliquus. Each complex is essentially free of chlorophyll and carotenoids and contains cytochrome b6 and cytochrome f hemes in a 2:1 molar ratio. C. reinhardtii and S. obliquus complexes contain the Rieske iron-sulfar protein (present in approx. 1:1 molar ratio to cytochrome f) and each catalyzes a DBMIB- and DNP-INT-sensitive electron transfer from duroquinol to spinach plastocyanin. Immunological assays using antibodies to the peptides from the spinach cytochrome complex show varying cross-reactivity patterns except for the complete absence of binding to the Rieske protein in any of the three complexes, suggesting little structural similarity between the Rieske proteins of algae with those from higher plants. One complex (D. salina) has been uniformly labeled by growth in NaH14CO3 to determine stoichiometries of constituent polypeptide subunits. Results from these studies indicate that all functionally active cytochrome b6-f complexes contain four subunits which occur in equimolar amounts.

关键词： Cytochrome f Cytochrome b 6 Rieske fe-S protein Plastoquinone Electron transfer DBMIB 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone DNP-INT 2-iodo-2′,4′,4′-trinitro-3-methyl-6-isopropyl diphenyl ether EPR electron paramagnetic resonance Rfe-S Rieske iron-sulfur protein SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis

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Preparation, characterisation and enhanced photocatalytic activities of fe,f co-doped TiO2 nanotubes

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MICRO & NANO LETTERS 2019年第1期14卷 66-68页

作者： Yu, Zhuanni Lan, Jing Wang, Qiang Qingdao Agr Univ Coll Chem & Pharmaceut Sci Qingdao 266109 Peoples R China

fe,f co-doped TiO2 nanotubes (fe,f/TiO2 NTs) were synthesised by the combination of hydrothermal process and impregnation method. The structure and composition of prepared catalysts were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). XRD results confirmed only the presence of the anatase phase in fe,f/TiO2 NTs. Well-defined TiO2 NTs with nearly uniform diameters could be seen from the TEM images. Also, the high-resolution XPS spectra of fe 2P and f 1s showed that fe3+ and f- existed in TiO2 lattice and on the surface of TiO2, respectively. The photocatalytic performances of fe/TiO2 NTs and fe,f/TiO2 NTs with different fe concentrations were evaluated by photo-degrading aqueous methyl orange under visible light irradiation, and the results showed that the photoactivity of fe and f co-doped TiO2 NTs was enhanced obviously compared with fe mono-doped TiO2 NTs and the 0.5% fe,f/TiO2 NTs presented the best photocatalytic performance.

关键词： catalysts transmission electron microscopy catalysis ultraviolet spectra X-ray photoelectron spectra semiconductor materials semiconductor nanotubes iron nanofabrication nanoparticles titanium compounds visible spectra X-ray diffraction photochemistry scanning electron microscopy semiconductor growth enhanced photocatalytic activities fe monodoped TiO2 nanotubes hydrothermal process impregnation method XRD X-ray diffraction TiO2:fe f time 1 0 s visible light irradiation photodegrading aqueous methyl orange TiO2 lattice f 1s fe 2P TEM images high-resolution XPS spectra anatase phase X-ray photoelectron spectroscopy TEM transmission electron microscopy

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Theoretical study on the mechanism for the reaction of f with CH₂CHCH₂Cl

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COMPUTATIONAL AND THEORETICAL CHEMISTRY 2012年 981卷 7-13页

作者： Zhang, Yunju Sun, Jingyu Chao, Kai Wang, fang Tang, ShuWei Pan, Xiumei Zhang, Jingping Sun, Hao Wang, Rongshun NE Normal Univ Inst Funct Mat Chem Fac Chem Changchun 130024 Jilin Peoples R China Jilin Univ Inst Theoret Chem State Key Lab Theoret & Computat Chem Changchun 130023 Jilin Peoples R China Ningxia Entry Exit Inspect & Quarantine Bur Ningxia 750001 Peoples R China

The complex potential energy surfaces for the reaction of atomic radical f with CH2CHCH2Cl (3-chloropropene) are explored at the CCSD(T)/cc-pVTZ//MP2(full)/6-311++G(d,p) level. There are various possible reaction pathways including the addition-elimination and H-abstraction reaction. Among them, the most feasible pathway should be to produce P1 (CH2CHCH2f + Cl), which is in good agreement with the experiment. Among the H-abstraction reactions, the most competitive pathway is the atomic radical f abstracting hydrogen atom from allylic group. Because all of the transition states and intermediates involved in the title reaction lie below the reactants, the f + CH2CHCH2Cl reaction is expected to be rapid. The present results could lead us to deeply understand the mechanism of the title reaction and may provide some useful information for future experimental investigation of the title reaction. (C) 2011 Elsevier B.V. All rights reserved.

关键词： f CH2CHCH2Cl Reaction mechanism CCSD(T) MP2

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Robust estimation of 1/f activity improves oscillatory burst detection

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EUROPEAN JOURNAL Of NEUROSCIENCE 2022年第10期56卷 5836-5852页

作者： Seymour, Robert A. Alexander, Nicholas Maguire, Eleanor A. UCL UCL Queen Sq Inst Neurol Dept Imaging Neurosci Wellcome Ctr Human Neuroimaging London WC1N 3AR England

Neural oscillations often occur as transient bursts with variable amplitude and frequency dynamics. Quantifying these effects is important for understanding brain-behaviour relationships, especially in continuous datasets. To robustly measure bursts, rhythmical periods of oscillatory activity must be separated from arrhythmical background 1/f activity, which is ubiquitous in electrophysiological recordings. The Better OSCillation (BOSC) framework achieves this by defining a power threshold above the estimated background 1/f activity, combined with a duration threshold. Here we introduce a modification to this approach called fBOSC, which uses a spectral parametrisation tool to accurately model background 1/f activity in neural data. fBOSC (which is openly available as a MATLAB toolbox) is robust to power spectra with oscillatory peaks and can also model non-linear spectra. Through a series of simulations, we show that fBOSC more accurately models the 1/f power spectrum compared with existing methods. fBOSC was especially beneficial where power spectra contained a 'knee' below similar to.5-10 Hz, which is typical in neural data. We also found that, unlike other methods, fBOSC was unaffected by oscillatory peaks in the neural power spectrum. Moreover, by robustly modelling background 1/f activity, the sensitivity for detecting oscillatory bursts was standardised across frequencies (e.g., theta- and alpha-bands). finally, using openly available resting state magnetoencephalography and intracranial electrophysiology datasets, we demonstrate the application of fBOSC for oscillatory burst detection in the theta-band. These simulations and empirical analyses highlight the value of fBOSC in detecting oscillatory bursts, including in datasets that are long and continuous with no distinct experimental trials.

关键词： 1 f burst detection neurophysiology oscillations signal processing theta

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THE PROTON PORE IN THE ESCHERICHIA-COLI f0f1-ATPASE - SUBSTITUTION Of GLUTAMATE BY GLUTAMINE AT POSITION-219 Of THE A-SUBUNIT PREVENTS f0-MEDIATED PROTON PERMEABILITY

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BIOCHIMICA ET BIOPHYSICA ACTA 1988年第2期933卷 241-248页

作者： LIGHTOWLERS, RN HOWITT, SM HATCH, L GIBSON, f COX, G Department of Biochemistry John Curtin School of Medical Research Canberra City ACT 2601 Australia

Three mutations in the uncB gene encoding the .alpha.-subunit of the f0 portion of the f0f1-ATPase of Escherichia coli were produced by site-directed mutagenesis. These mutations directed the substitution of Glu-219 by Gln, or of Lys-203 by Ile, or of Glu-196 by Ala. Strains carrying either the Lys-203 or Glu-196 substitutions showed growth characteristics indistinguishable from the coupled control strain. Properties of membrane preparations from these strains were also similar to those from the coupled control strain. The substitution of Glu-219 by Gln resulted in a strain which was unable to utilise succinate as sole carbon source and had a growth-yield characteristic of an uncoupled strain. Membrane preparations of the Glu-219 mutant were proton impermeable and the f1-ATPase activity was inhibited by about 50% when membrane-bound. The results are discussed with reference to a previously proposed intramembranous proton pore involving subunits a and c.

关键词： ATPase, f 0 f 1 - Proton channel Site directed mutagenesis Proton permeability ( E. coli ) DCCD N , N ′-dicyclohexylcarbodiimide

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ELECTRON-PARAMAGNETIC RESONANCE EVIDENCE Of METAL-ION BINDING-SITES IN MICROCOCCUS-LYSODEIKTICUS (M-LUTEUS) f1-ATPASE

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BIOCHIMICA ET BIOPHYSICA ACTA 1986年第2期848卷 224-229页

作者： MOLLINEDO, f CANNISTRARO, S UNIV PERUGIA DEPARTIMENTO FIS BIOF MOLECOL GRP I-06100 PERUGIA ITALY

Evidence is presented for the presence of divalent cation binding sites in purified f1-ATPase from Micrococcus lysodeikticus (Micrococcus luteus). Electron paramagnetic resonance studies of native f1-ATPase indicate that the enzyme binds Mn2+ and Cu2+. Scatchard-type plot for Mn2+ binding to the enzyme indicates the presence of 3-4 independent and identical sites with a dissociation constant of 18.3 .cntdot. 10-6 M. Cu2+ binds to the enzyme at only one kind of site(s). This Cu2+ binding site(s) is characterized by a moderately ionic ligand field provived by the protein and by a tetragonal symmetry of nitrogen and/or oxygen ligands. Competition studies indicate that Mg2+ binds at these Mn2+ and Cu2+ binding sites.

关键词： f 1 -ATPase ESR Cu 2+ -binding site Mg 2+ -binding site ( M. lysodeikticus, M. luteus )

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