排序方式: 共有42条查询结果,搜索用时 15 毫秒
21.
Jitka Cejkova Vadym Prokopec Alzbeta Kokaislova Frantisek Stepanek 《Applied Surface Science》2009,255(18):7864-7870
Surface Enhanced Raman Scattering (SERS) on copper substrates of various morphologies, prepared by electrochemical deposition on platinum targets, was investigated. The substrate preparation procedures differed by the coating bath compositions, applied current densities and the duration of individual steps. The surface morphology of the substrates was visualized by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). SERS spectra of selected organic thiols were measured and the relation between SERS spectral intensity and the surface structure of SERS-active substrates was studied. It has been shown that good Raman surface enhancement can be achieved on the copper substrates prepared by electrochemical deposition from ammoniac baths. Copper substrates fabricated from acidic baths did not show efficient Raman surface enhancement. The results of microscopic measurements demonstrated that the average surface roughness value does not play a substantial role, whereas the shape of the surface nanostructures is a key parameter. 相似文献
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Zint D. Grosso R. Aizinger V. Köstler H. 《Computational Mathematics and Mathematical Physics》2019,59(12):2108-2123
Computational Mathematics and Mathematical Physics - In high performance computing, block structured grids are favored due to their geometric adaptability while supporting computational performance... 相似文献
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Vadym V. Kulish Dr. Man‐Fai Ng Oleksandr I. Malyi Prof. Ping Wu Prof. Zhong Chen 《Chemphyschem》2013,14(6):1161-1167
We report a first‐principles investigation of Li adsorption and diffusion in single‐walled Si nanotubes (SWSiNTs) of interest to Li‐ion battery anodes. We calculate Li insertion characteristics in SWSiNTs and compare them with the respective ones in carbon nanotubes (CNTs) and other silicon nanostructures. From our calculations, SWSiNTs show higher reactivity toward the adsorption of Li adatoms than CNTs and Si nanoclusters. Considering the importance of Li kinetics, we demonstrate that the interior of SWSiNTs may serve as a fast Li diffusion channel. The important advantage of SWSiNTs over their carbon analogues is a sevenfold reduction in the energy barrier for the penetration of the Li atoms into the nanotube interior through the sidewalls. This prepossesses easier Li diffusion inside the tube and subsequent utilization of the interior sites, which enhances Li storage capacity of the system. The improvements in both Li uptake and Li mobility over their analogues support the great potential of SWSiNTs as Li‐ion battery anodes. 相似文献
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Laiko VV Taranenko NI Berkout VD Yakshin MA Prasad CR Lee HS Doroshenko VM 《Journal of the American Society for Mass Spectrometry》2002,13(4):354-361
A new atmospheric pressure (AP) infrared (IR) matrix-assisted laser desorption/ionization (MALDI) ion source was developed and interfaced with a Thermo Finnigan LCQ ion trap mass spectrometer. The source utilized a miniature all-solid-state optical parametric oscillator (OPO)-based IR laser system tunable in the lambda = 1.5-4 microm spectral range and a nitrogen ultraviolet (UV) laser (lambda = 337 nm) for use in comparative studies. The system demonstrated comparable performance at 3 microm and 337 nm wavelengths if UV matrices were used. However, AP IR-MALDI using a 3 microm wavelength showed good performance with a much broader choice of matrices including glycerol and liquid water. AP IR-MALDI mass spectra of peptides in the mass range up to 2000 Da were obtained directly from aqueous solutions at atmospheric conditions for the first time. A potential use of the new AP IR-MALDI ion source includes direct MS analysis of biological cells and tissues in a normal atmospheric environment as well as on-line coupling of mass spectrometers with liquid separation techniques. 相似文献
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Magdalyna Ignatovych Vadym Holovey Andrea Watterich Tams Vidczy Pter Baranyai Andrs Kelemen Oleksij Chuiko 《Radiation measurements》2004,38(4-6):567-570
Photoluminescence, radioluminescence as well as optical absorption techniques were used to characterize Cu- and Eu-doped lithium tetraborate. The effect of host modification (single crystal and glassy state) and a limited range of dopant content were investigated. Time-resolved measurements were helpful to identify the emitting species. 相似文献
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The effect of fringing fields on the divergence of the ion beam exiting an RF quadrupole ion guide was studied using a computer simulation. It was shown that reducing the strength of the RF field towards the ion guide exit reduces ion beam divergence. Further improvement was demonstrated when creating a DC gradient towards the exit. The results of the numerical simulation were verified experimentally using a time-of-flight (TOF) mass analyzer with orthogonal acceleration. Decreasing the ion beam divergence resulted in considerably improved mass resolution of the instrument. 相似文献
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Tatyana Saplinova Vadym Bakumov Tobias Gmeiner Jörg Wagler Marcus Schwarz Edwin Kroke Prof. Dr. 《无机化学与普通化学杂志》2009,635(15):2480-2487
The title compound C6N7(NHNH2)3 ( 1 ) was obtained from melem C6N7(NH2)3 or melon [C6N7(NH2)NH]n and hydrazine by an autoclave synthesis. Upon treatment with a 10 % HCl solution it is transformed into the trihydrochloride [C6N7(NHNH3)3]Cl3 ( 2 ). Compounds 1 and 2 were analysed with 13C NMR, 15N NMR, FTIR and Raman spectroscopy. Furthermore, the single‐crystal X‐ray structure of the pentahydrate of 2 is reported (P\bar{1} , a = 674.96(3), b = 1214.17(6), c = 1272.15(6) pm, α = 66.288(2)°, β = 75.153(2)°, γ = 80.420(2)°, V = 920.30(8)·106 pm3, Z = 2, T = 90(2) K). The thermal decomposition of 1 and 2 was investigated with TG/DTA. Reaction of 1 with NaNO2/HCl yields triazido‐s‐heptazine, C6N7(N3)3 ( 3 ). Tris(tri‐n‐butylphosphinimino)‐s‐heptazine ( 4 ) was synthesised from 3 and characterised by means of 13C, 31P, 1H NMR, FTIR and MALDI‐TOF spectroscopy. Similar to s‐heptazine derivative 3 , compounds 1 and 4 are precursors for graphitic carbon nitrides, which have attracted considerable attention recently, and to various potential applications, such as flame retardants and (photo) catalysis. 相似文献
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Valentyna P. Tokar Mykhaylo Yu. Losytskyy Tymish Y. Ohulchanskyy Dmytro V. Kryvorotenko Vladyslava B. Kovalska Anatoliy O. Balanda Igor M. Dmytruk Vadym M. Prokopets Sergiy M. Yarmoluk Valeriy M. Yashchuk 《Journal of fluorescence》2010,20(4):865-872
Spectral-fluorescent properties of benzothiazole styryl monomer (Bos-3) and homodimer (DBos-21) dyes in presence of DNA were
studied. The dyes enhance their fluorescence intensity in 2–3 orders of magnitude upon interaction with DNA. Studied styrylcyanines
in DNA presence demonstrate rather high values of two-photon absorption (TPA) cross-section, which are comparable with the
values of TPA cross section of the rhodamine dyes. An applicability of the styrylcyanines as probes for the fluorescence microscopy
of living cells was studied. It was shown that both dyes are cell-permeable but homodimer dye DBos-21 produces noticeably
brighter staining of HeLa cells comparing with monomer dye Bos-3. Molecules of DBos-21 initially bind to the nucleic acids-
containing cell organelles (presumable mitochondria) and are able to penetrate into the cell nucleus. Thus, homodimer styryl
DBos-21 dye is viewed as efficient stain for single-photon and two-photon excitation fluorescence imaging of living cells. 相似文献