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1.
Photoinduced optical and second-order non-linear optical effects in the interfaces separating In2O3–SiON (O/N ratio equals 1) films doped with A1, Sn and glass substrates were investigated using the photoinduced optical second harmonic generation. The photoinduced effective second-order optical susceptibility deff (at λ=1.76 μm) shows a good correlation with the linear optical susceptibility, particularly with the shift of the absorption edge. The maximal response of the photoinduced optical response signal was observed for the pump–probe delaying time of 34 ps. The performed experimental measurements indicate that the observed effects are mainly caused by the interface potential gradients on the border glass–In2O3–SiON film and by additional polarization due to insertion of the Al and Sn atoms. The observed phenomenon may be proposed as a sensitive tool for investigation of thin semiconducting interfacial layers and simultaneously such films may be used as materials for non-linear optical devices. 相似文献
2.
Reversible storage of molecular hydrogen by sorption into multilayered TiO2 nanotubes 总被引:4,自引:0,他引:4
Bavykin DV Lapkin AA Plucinski PK Friedrich JM Walsh FC 《The journal of physical chemistry. B》2005,109(41):19422-19427
The sorption of hydrogen between the layers of the multilayered wall of nanotubular TiO2 was studied in the temperature range of -195 to 200 degrees C and at pressures of 0 to 6 bar. Hydrogen can intercalate between layers in the walls of TiO2 nanotubes forming host-guest compounds TiO2 x xH2, where x < or = 1.5 and decreases at higher temperatures. The rate of hydrogen incorporation increases with temperature and the characteristic time for hydrogen sorption in TiO2 nanotubes is several hours at 100 degrees C. The rate of intercalate formation is limited by the diffusion of molecular hydrogen inside the multilayered walls of the TiO2 nanotube. 1H NMR-MAS and XRD data confirm the incorporation of hydrogen between the layers in the walls of TiO2 nanotubes. The nature and possible applications of the observed intercalates are considered. 相似文献
3.
The shear flow of mayonnaise is generally characterized by an apparent yield stress, shear thinning in steady flow, stress
overshoots upon inception of flow and other time-dependent effects. These observations are usually understood to be the result
of structural rearrangement within the material. Additionally and separately, the possibility that emulsions may exhibit apparent
wall slip on a microscopic scale at a solid-liquid boundary has been reported by some researchers. Thus, observed rheological
behavior is likely to be the result of the interplay between these two phenomena.
In the present work, it is demonstrated that when measurements are sought to be made on mayonnaise using rotational viscometers
visible wall slip occurs, rendering such instruments ineffective for the purpose of making viscosity measurements even at
shear rates as low as 10–3s–1. The factors that influence the onset and extent of slip are investigated with the help of parallel plate viscometers, and
it is concluded that the observed “yielding” of mayonnaise is actually an artifact of the onset of macroscopic slip. Slip
effects are also found in capillary flow but are ameliorated with increasing shear rate. To circumvent these problems, it
is proposed that extensional viscometry be employed for determining the flow behavior of mayonnaises.
Received: 18 August 1997 Accepted: 1 April 1998 相似文献
4.
The stable benzylazido-boronate ester 1 is presented as an example of a dual-functional linker that allows the synthetically valuable boronate motif to be clicked onto other molecules under mild conditions. The utility of the azido-boronate motif as a modular building block is demonstrated in the rapid synthesis of drug-like structures employing sequential catalytic azide-alkyne cycloaddition and Suzuki coupling reactions. 相似文献
5.
Sumeet K. Sharma Simon D. BishoppC. Liana Allen Ruth LawrenceMark J. Bamford Alexei A. LapkinPawel Plucinski Robert J. WatsonJonathan M.J. Williams 《Tetrahedron letters》2011,52(33):4252-4255
The atom-efficient and cost-effective rearrangement of oximes into primary amides is catalyzed by simple copper salts. The use of homogeneous Cu(OAc)2 (1-2 mol %) was found to be effective for this transformation at 80 °C. The reaction was successful with either conventional or microwave heating. CuO and CuO/ZnO on activated carbon provided a competent reuseable heterogeneous catalyst which could be used in a batch process or in flow. Copper salts are much cheaper than the precious metals previously used for this rearrangement, and the reaction conditions are milder than those reported. 相似文献
6.
We have studied the photoinduced effects in the nanocrystallized Y3Fe5O12 films deposited on the Gd3Ga5O12 <1 1 1> substrates. We have found for the first time substantial changes of the birefringence, two-photon absorption and circularly polarized absorption in different regimes of treatment of the nanocrystallized films. The explanations of the observed phenomena are suggested. The absorption spectra were modeled by the DFT based calculations of the electronic structure and density of states, which have revealed the well-pronounced differences between the densities of states of the tetra- and octahedrally coordinated iron ions. In addition, the crystal field calculations of the Fe3+ energy levels at the octahedral and tetrahedral positions have been performed. 相似文献
7.
William Mahy Dr. Pawel Plucinski Dr. Jesús Jover Prof. Dr. Christopher G. Frost 《Angewandte Chemie (International ed. in English)》2015,54(37):10944-10948
A practical ruthenium‐catalyzed O‐ to S‐alkyl migration affords structurally diverse thiooxazolidinones in excellent yields. Our studies suggest this catalytic transformation proceeds through a pseudoreversible radical pathway drawing mechanistic parallels to the classic Barton–McCombie reaction. 相似文献
8.
C.M. Schneider C. Wiemann M. Patt V. Feyer L. Plucinski I.P. Krug M. Escher N. Weber M. Merkel O. Renault N. Barrett 《Journal of Electron Spectroscopy and Related Phenomena》2012
The analysis of chemical and electronic states in complex and nanostructured material systems requires electron spectroscopy to be carried out with nanometer lateral resolution, i.e. nanospectroscopy. This goal can be achieved by combining a parallel imaging photoelectron emission microscope with a bandpass energy filter. In this contribution we describe selected experiments employing a dedicated spectromicroscope – the NanoESCA. This instrument has a particular emphasis on the spectroscopic aspects and enables laterally resolved photoelectron spectroscopy from the VUV up into the hard X-ray regime. 相似文献
9.
Colakerol L Veal TD Jeong HK Plucinski L DeMasi A Learmonth T Glans PA Wang S Zhang Y Piper LF Jefferson PH Fedorov A Chen TC Moustakas TD McConville CF Smith KE 《Physical review letters》2006,97(23):237601
Electron accumulation states in InN have been measured using high resolution angle-resolved photoemission spectroscopy (ARPES). The electrons in the accumulation layer have been discovered to reside in quantum well states. ARPES was also used to measure the Fermi surface of these quantum well states, as well as their constant binding energy contours below the Fermi level E(F). The energy of the Fermi level and the size of the Fermi surface for these quantum well states could be controlled by varying the method of surface preparation. This is the first unambiguous observation that electrons in the InN accumulation layer are quantized and the first time the Fermi surface associated with such states has been measured. 相似文献
10.
Generation of GW radiation pulses from a VUV free-electron laser operating in the femtosecond regime
Ayvazyan V Baboi N Bohnet I Brinkmann R Castellano M Castro P Catani L Choroba S Cianchi A Dohlus M Edwards HT Faatz B Fateev AA Feldhaus J Flöttmann K Gamp A Garvey T Genz H Gerth Ch Gretchko V Grigoryan B Hahn U Hessler C Honkavaara K Hüning M Ischebeck R Jablonka M Kamps T Körfer M Krassilnikov M Krzywinski J Liepe M Liero A Limberg T Loos H Luong M Magne C Menzel J Michelato P Minty M Müller UC Nölle D Novokhatski A Pagani C Peters F Pflüger J Piot P Plucinski L Rehlich K Reyzl I Richter A 《Physical review letters》2002,88(10):104802
Experimental results are presented from vacuum-ultraviolet free-electron laser (FEL) operating in the self-amplified spontaneous emission (SASE) mode. The generation of ultrashort radiation pulses became possible due to specific tailoring of the bunch charge distribution. A complete characterization of the linear and nonlinear modes of the SASE FEL operation was performed. At saturation the FEL produces ultrashort pulses (30-100 fs FWHM) with a peak radiation power in the GW level and with full transverse coherence. The wavelength was tuned in the range of 95-105 nm. 相似文献