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排序方式: 共有222条查询结果,搜索用时 31 毫秒
81.
82.
Phu Tran Phong Le Kevin Hofhuis Abhimanyu Rana Mark Huijben Hans Hilgenkamp Guus A.J.H.M. Rijnders Johan E. ten Elshof Gertjan Koster Nicolas Gauquelin Gunnar Lumbeeck Christian Schüßler‐Langeheine Horia Popescu Franck Fortuna Steef Smit Xanthe H. Verbeek Georgios Araizi‐Kanoutas Shrawan Mishra Igor Vaskivskyi Hermann A. Dürr Mark S. Golden 《Advanced functional materials》2020,30(1)
Vanadium dioxide (VO2) is a much‐discussed material for oxide electronics and neuromorphic computing applications. Here, heteroepitaxy of VO2 is realized on top of oxide nanosheets that cover either the amorphous silicon dioxide surfaces of Si substrates or X‐ray transparent silicon nitride membranes. The out‐of‐plane orientation of the VO2 thin films is controlled at will between (011)M1/(110)R and (?402)M1/(002)R by coating the bulk substrates with Ti0.87O2 and NbWO6 nanosheets, respectively, prior to VO2 growth. Temperature‐dependent X‐ray diffraction and automated crystal orientation mapping in microprobe transmission electron microscope mode (ACOM‐TEM) characterize the high phase purity, the crystallographic and orientational properties of the VO2 films. Transport measurements and soft X‐ray absorption in transmission are used to probe the VO2 metal–insulator transition, showing results of a quality equal to those from epitaxial films on bulk single‐crystal substrates. Successful local manipulation of two different VO2 orientations on a single substrate is demonstrated using VO2 grown on lithographically patterned lines of Ti0.87O2 and NbWO6 nanosheets investigated by electron backscatter diffraction. Finally, the excellent suitability of these nanosheet‐templated VO2 films for advanced lensless imaging of the metal–insulator transition using coherent soft X‐rays is discussed. 相似文献
83.
Treatment of a variety of N-acyliminium ion precursors with 2,3-butadienyl(trimethyl)silane and related allenes in the presence of BF(3).OEt(2) provides good yields of N-protected 2-(aminomethyl)-substituted 1,3-dienes, which prove to be useful substrates for subsequent Diels-Alder and alkene metathesis reactions. [reaction: see text] 相似文献
84.
By preparing a population of triplet states through excitation with a laser pulse of 308 nm, we could determine the resonance Raman spectra of acridine and of anthracene in their lowest (π π*) state, T0. Thirty Raman lines in the region between 200 and 2000 cm?1 are reported for acridine in the T0 state. These are attributed to either a1 or b2 vibrational modes. Nineteen Raman lines between 500 and 2000 cm?1 are reported for anthracene in the T0 state. 相似文献
85.
Comparative proteomics of human endothelial cell caveolae and rafts using two-dimensional gel electrophoresis and mass spectrometry 总被引:5,自引:0,他引:5
Sprenger RR Speijer D Back JW De Koster CG Pannekoek H Horrevoets AJ 《Electrophoresis》2004,25(1):156-172
The human endothelial cell plasma membrane harbors two subdomains of similar lipid composition, caveolae and rafts, both crucially involved in various essential cellular processes like transcytosis, signal transduction and cholesterol homeostasis. Caveolin-enriched membranes, isolated by either cationic silica or buoyant density methods, were explored by comparing large series of two-dimensional (2-D) maps and subsequent identification of over 100 protein spots by matrix-assisted laser desorption/ionization (MALDI) peptide mass fingerprinting. Improved representation and identification of membrane proteins and valuable information on various post-translational modifications was achieved by the presented optimized procedures for solubilization, destaining and database searching/computing. Whereas the cationic silica purification yielded predominantly known endoplasmic reticulum residents, the cold-detergent method yielded a large number of known caveolae residents, including caveolin-1. Thus, a large part of this subproteome was established, including known (trans-)membrane, signal transduction and glycosyl phosphatidylinositol (GPI)-anchored proteins. Several predicted proteins from the human genome were isolated for the first time from biological samples, including SGRP58, SLP-2, C8ORF2, and XRP-2. These findings and various optimized procedures can serve as a reference to study the differential composition of endothelial cell caveolae and rafts, known to be involved in pathologies like cancer and cardiovascular disease. 相似文献
86.
Homsy A Koster S Eijkel JC van den Berg A Lucklum F Verpoorte E de Rooij NF 《Lab on a chip》2005,5(4):466-471
This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-microm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined frit-like structure that connects the pumping channel to side reservoirs, where platinum electrodes are located. Current densities up to 4000 A m(-2) could be obtained without noticeable Joule heating in the system. The pump performance was studied as a function of current density and magnetic field intensity, as well as buffer ionic strength and pH. Bead velocities of up to 1 mm s(-1) (0.5 microL min(-1)) were observed in buffered solutions using a 0.4 T NdFeB permanent magnet, at an applied current density of 4000 A m(-2). This pump is intended for transport of electrolyte solutions having a relatively high ionic strength (0.5-1 M) in a DC magnetic field environment. The application of this pump for the study of biological samples in a miniaturized total analysis system (microTAS) with integrated NMR detection is foreseen. In the 7 T NMR environment, a minimum 16-fold increase in volumetric flow rate for a given applied current density is expected. 相似文献
87.
88.
T. Brenner S. Büttgenbach J. Jacobs M. Koster H. Roeder W. Rupprecht F. Träber 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1988,10(1):59-70
The hyperfine structure splittings of 32 even parity states and of 26 odd partity states of molybdenum have been measured by atomic beam magnetic resonance and by laser induced fluorescence. The analysis of the hyperfine structure data of the even parity configurations (4d+5s)6 yields experimental evidence for second order hyperfine interactions. In addition, theg J factors of 19 fine structure levels have been determined in order to test the quality of intermediate coupling wave functions for the (4d+5s)6 configurations. 相似文献
89.
Drescher M Veldhuis G van Rooijen BD Milikisyants S Subramaniam V Huber M 《Journal of the American Chemical Society》2008,130(25):7796-7797
alpha-Synuclein (alphaS) is the main component of Lewy bodies from Parkinson's disease. That alphaS binds to membranes is known, but the conformation it adopts is still unclear. Pulsed EPR on doubly spin-labeled variants of alphaS sheds light on the most likely structure. For alphaS bound to vesicles large enough to accommodate also the extended conformation, an antiparallel helix conformation is found. This suggests that the bent structure shown is the preferred conformation of alphaS on membranes. 相似文献
90.