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891.
The grafting of polypyrrole onto the surface of modified silica nanoparticles has been investigated. These silica nanoparticles were modified with pyrrole moieties prepared by the well-known Stober method in one-step starting from TEOS and a pyrrole-bearing trialkoxysilane compound. The effects of various reaction conditions, including reaction time, solvent, and molar ratio of water to alkoxy groups, have been investigated in order to obtain pyrrole-modified silica nanoparticles with the optimal core–shell structure and the smallest possible particle size. The grafting was carried out in aqueous FeCl3 solution containing the modified silica nanoparticles, with pyrrole monomers already adsorbed on the surface of the particles by soaking. Several analytical tools have been employed to characterize the particles and to assess the degree of grafting, namely TEM, SEM, TGA, FTIR, and XPS. The final polypyrrole-grafted silica nanoparticles obtained had a mean diameter of about 220 nm and 50 wt.% of grafted polypyrrole with respect to the total weight of polypyrrole formed around the surface of the cores. 相似文献
892.
Ralf Jäger Martin Purpura Kurt-Reiner Geiss Michael Weiß Jochen Baumeister Francesco Amatulli Lars Schröder Holger Herwegen 《Journal of the International Society of Sports Nutrition》2007,4(1):23-5
Background
A randomized, double-blind, placebo-controlled study was performed to evaluate the effect of oral phosphatidylserine (PS) supplementation on golf performance in healthy young golfers with handicaps of 15–40. 相似文献893.
894.
895.
896.
Barsi Ferruccio Bertossi Alan A. Betti Sorbelli Francesco Ciotti Roberto Olariu Stephan Pinotti M. Cristina 《Parallel and Distributed Systems, IEEE Transactions on》2009,20(8):1216-1230
Scalable energy-efficient training protocols are proposed for wireless networks consisting of sensors and a single actor, where the sensors are initially anonymous and unaware of their location. The protocols are based on an intuitive coordinate system imposed onto the deployment area, which partitions the sensors into clusters. The protocols are asynchronous, in the sense that the sensors wake up for the first time at random, then alternate between sleep and awake periods both of fixed length, and no explicit synchronization is performed between them and the actor. Theoretical properties are stated under which the training of all the sensors is possible. Moreover, both worst-case and average case analyses of the performance, as well as an experimental evaluation, are presented showing that the protocols are lightweight and flexible. 相似文献
897.
898.
A numerical photogrammetry technique for measuring microscale kinematics and fabric in Schneebeli materials 总被引:1,自引:0,他引:1
We present a numerical photogrammetry technique for obtaining semi–automated measurements concerning kinematic fields, i.e.
translation and rotation of each “grain”, and fabric properties of a two-dimensional analogue granular material. An example
is given in which the technique is applied in a biaxial compression test on a specimen consisting of 1,300 rods. The information
that can be recorded by the technique is discussed along with its accuracy.
This work is funded by the EU project Degradation and Instabilities in Geomaterials with Application to Hazard Mitigation (DIGA) in the framework of the Human Potential Program, Research Training Networks (HPRN-CT-2002-00220). 相似文献
899.
Gaetano Giunta Francesco Benedetto 《Communications, IEEE Transactions on》2007,55(2):257-261
A new special function, called the modified generalized Q (MGQ) function, is here defined to analytically express the performance of the pseudonoise code acquisition based on matched filter correlators. In the considered case of two cells per chip, no convergent infinite series have been found in the open literature expressing the probabilities of false alarm and detection. The performance is analyzed in terms of mean acquisition time for signal-to-noise ratios of practical interest 相似文献
900.
Francesco G. Della Corte Fortunato Pezzimenti Roberta Nipoti 《Microelectronics Journal》2007,38(12):1273-1279
In this work the forward J–V characteristics of 4H–SiC p–i–n diodes are analysed by means of a physics based device simulator tuned by comparison to experimental results. The circular devices have a diameter of 350 μm. The implanted anode region showed a plateau aluminium concentration of 6×1019 cm−3 located at the surface with a profile edge located at 0.2 μm and a profile tail crossing the n-type epilayer doping at 1.35 μm. Al atom ionization efficiency was carefully taken into account during the simulations. The final devices showed good rectifying properties and at room temperature a diode current density close to 370 A/cm2 could be measured at 5 V. The simulation results were in good agreement with the experimental data taken at temperatures up to about 523 K in the whole explored current range extending over nine orders of magnitude. Simulations also allowed to estimate the effect of a different p+ doping electrically effective profile on the device current handling capabilities. 相似文献