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21.
Luchita G Bondar MV Yao S Mikhailov IA Yanez CO Przhonska OV Masunov AE Belfield KD 《ACS applied materials & interfaces》2011,3(9):3559-3567
Efficient reversible phototransformation of a new diarylethene-fluorene derivative, 1,2-bis(5-(9,9-didecyl-7-nitro-9H-fluoren-2-yl)-2-methylthiophen-3-yl)cyclopent-1-ene (1), was demonstrated in organic media under low-intensity laser excitation. Linear photophysical characterization of 1 was performed at room temperature in solvents of different polarity and viscosity. Significantly, close to unity quantum yield for the cyclization reaction of 1 was shown in nonpolar solutions. The lifetimes of the excited states of the open (OF) and closed (CF) forms of 1 were measured by a femtosecond transient absorption technique, and corresponding values of ~0.7 and ~0.9 ps were shown in dichloromethane (DCM), respectively. Degenerate two-photon absorption (2PA) spectra of the OF and CF of 1 were obtained over a broad spectral range by the open aperture Z-scan method under 1 kHz femtosecond excitation. The values of 2PA cross sections of the OF in DCM (~50-70 GM) were found to increase up to 1 order of magnitude (~600 GM) after cyclization to the CF. The nature of cyclization and cylcoreversion processes were investigated by quantum chemistry with employment of DFT-based methods implemented in the Gaussian'09 program. The potential of 1 for application in optical data storage was shown using poly(methyl methacrylate)-doped films and two-photon fluorescence microscopy readout. 相似文献
22.
Marta Valkov Pavel Letinský Lenka Matjov Kateina Klemencov Michal Ritz Christian Schimpf Mykhailo Motylenko David Rafaja Jakub Blík 《International journal of molecular sciences》2022,23(15)
Hematite (α-Fe2O3) catalysts prepared using the precipitation methods was found to be highly effective, and therefore, it was studied with methane (CH4), showing an excellent stable performance below 500 °C. This study investigates hematite nanoparticles (NPs) obtained by precipitation in water from the precursor of ferric chloride hexahydrate using precipitating agents NaOH or NH4OH at maintained pH 11 and calcined up to 500 °C for the catalytic oxidation of low concentrations of CH4 (5% by volume in air) at 500 °C to compare their structural state in a CH4 reducing environment. The conversion (%) of CH4 values decreasing with time was discussed according to the course of different transformation of goethite and hydrohematites NPs precursors to magnetite and the structural state of the calcined hydrohematites. The phase composition, the size and morphology of nanocrystallites, thermal transformation of precipitates and the specific surface area of the NPs were characterized in detail by X-ray powder diffraction, transmission electron microscopy, infrared spectroscopy, thermal TG/DTA analysis and nitrogen physisorption measurements. The results support the finding that after goethite dehydration, transformation to hydrohematite due to structurally incorporated water and vacancies is different from hydrohematite α-Fe2O3. The surface area SBET of Fe2O3_NH-70 precipitate composed of protohematite was larger by about 53 m2/g in comparison with Fe2O3_Na-70 precipitate composed of goethite. The oxidation of methane was positively influenced by the hydrohematites of the smaller particle size and the largest lattice volume containing structurally incorporated water and vacancies. 相似文献
23.
Adam K. Budniak Niall A. Killilea Szymon J. Zelewski Mykhailo Sytnyk Yaron Kauffmann Yaron Amouyal Robert Kudrawiec Wolfgang Heiss Efrat Lifshitz 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(1)
Layered semiconductors have attracted significant attention due to their diverse physical properties controlled by composition and the number of stacked layers. Herein, large crystals of the ternary layered semiconductor chromium thiophosphate (CrPS4) are prepared by a vapor transport synthesis. Optical properties are determined using photoconduction, absorption, photoreflectance, and photoacoustic spectroscopy exposing the semiconducting properties of the material. A simple, one‐step protocol for mechanical exfoliation onto a transmission electron microscope grid is developed, and multiple layers are characterized by advanced electron microscopy methods, including atomic resolution elemental mapping confirming the structure by directly showing the positions of the columns of different elements' atoms. CrPS4 is also liquid exfoliated, and in combination with colloidal graphene, an ink‐jet‐printed photodetector is created. This all‐printed graphene/CrPS4/graphene heterostructure detector demonstrates a specific detectivity of 8.3 × 108 (D*). This study shows a potential application of both bulk crystal and individual flakes of CrPS4 as active components in light detection, when introduced as ink‐printable moieties with a large benefit for manufacturing. 相似文献
24.
Mykhailo Chaika Wojciech Paszkowicz Wiesław Strek Dariusz Hreniak Robert Tomala Nadiya Safronova Andriy Doroshenko Sergiy Parkhomenko Piotr Dluzewski Mirosław Kozłowski Oleh Vovk 《Journal of the American Ceramic Society》2019,102(4):2104-2115
In the present work, the influence of Cr and Ca co-additives on the phase formation under conditions emulated the real sintering process of Cr4+:YAG ceramics is studied. The XRD analysis of the treated samples revealed the difference in formation rates of intermediate phases between the samples with and without the Cr2O3 additive. The formation of intermediate phases in the solid-state reaction between Y2O3 and Al2O3 is observed to shift toward higher temperatures (ie, toward the stage of fast shrinkage) if the mixture of Cr2O3 and CaO is added. The reason for such shift is the appearance of new intermediate, which contains Cr4+ ions in perovskite structure, as has been established by optical absorption and luminescent investigations. It is found that the Cr,Ca:YAG ceramics prepared by vacuum solid state reaction sintering at 1750°C, 10 hours possesses better optical transparency than Ca:YAG ceramics prepared under the same conditions. 相似文献
25.
26.
V. A. Boguslayev V. K. Yatsenko A. G. Sakhno N. V. Gonchar 《Strength of Materials》1998,30(5):551-555
The results of the present study suggest that a fatigue limit of the crown interslot projections of gas-turbine engine disks
made of the KhN73MBTYu-VD alloy can be raised by subjecting the surface layer of the disk slots to ultrasonic hardening with
balls. We attribute this to a removal of abrasive grits left by previous machining, to a decrease in depletion of the surface
in alloying elements, and a simultaneous improvement in uniformity of the stress-strain state of various sections of the surface
of a slot.
Translated from Problemy Prochnosti, No. 5, pp. 126–133, September–October, 1998. 相似文献
27.
An analysis is made of the temperature dependence of the electrical conductivity of undoped nonstoichiometric indium oxide
films. Activation energies are obtained for the formation of oxygen vacancies and for the mobility of quasifree carriers.
Pis’ma Zh. Tekh. Fiz. 24, 1–5 (February 12, 1998) 相似文献
28.
Effect of Gamma Irradiation on Dynamics of Charge Exchange Processes between Single Trap and Nanowire Channel
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Ihor Zadorozhnyi Jing Li Hanna Hlukhova Volodymyr Handziuk Yurii Kutovyi Mykhailo Petrychuk Svetlana Vitusevich 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(2)
In the present study, transport properties and single trap phenomena in silicon nanowire (NW) field‐effect transistors (FETs) are reported. The dynamic behavior of drain current in NW FETs studied before and after gamma radiation treatment deviates from the predictions of the Shockley–Read–Hall model and is explained by the concept taking into account an additional energy barrier in the accumulation regime. It is revealed that dynamics of charge exchange processes between single trap and nanowire channel strongly depend on gamma radiation treatment. The results represent potential for utilizing single trap phenomena in a number of advanced devices. 相似文献
29.
Gonchar A. V. Klyushnikov V. A. Mishakin V. V. Anosov M. S. 《Russian Journal of Nondestructive Testing》2021,57(7):570-578
Russian Journal of Nondestructive Testing - We investigated the process of fatigue damage in welded joints made of austenitic steel by ultrasonic and eddy current types of testing. The development... 相似文献
30.
Gonchar A. V. Klyushnikov V. A. Mishakin V. V. Anosov M. S. 《Russian Journal of Nondestructive Testing》2021,57(9):823-823
Russian Journal of Nondestructive Testing - An Erratum to this paper has been published: https://doi.org/10.1134/S1061830921090126 相似文献