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81.
Hopp B. Smausz T. Kresz N. Nagy P.M. Juhász A. Ignácz F. Márton Z. 《Applied Physics A: Materials Science & Processing》2003,76(5):731-735
Allergic-type diseases are current nowadays, and they are frequently caused by certain metals. We demonstrated that the metal
objects can be covered by Teflon protective thin layers using a pulsed laser deposition procedure. An ArF excimer laser beam
was focused onto the surface of pressed PTFE powder pellets; the applied fluences were 7.5–7.7 J/cm2. Teflon films were deposited on fourteen-carat gold, silver and titanium plates. The number of ablating pulses was 10000.
Post-annealing of the films was carried out in atmospheric air at oven temperatures between 320 and 500 °C. The thickness
of the thin layers was around 5 μm. The prepared films were granular without heat treatment or after annealing at a temperature
below 340 °C. At 360 °C a crystalline, contiguous, smooth, very compact and pinhole-free thin layer was produced; a melted
and re-solidified morphology was observed above 420 °C. The adhesion strength between the Teflon films and the metal substrates
was determined. This could exceed 1–4 MPa depending on the treatment temperature. It was proved that the prepared Teflon layers
can be suitable for prevention of contact between the human body and allergen metals and so for avoidance of metal allergy.
Received: 12 June 2002 / Accepted: 13 June 2002 / Published online: 4 November 2002
RID="*"
ID="*"Corresponding author. E-mail: bhopp@physx.u-szeged.hu 相似文献
82.
83.
We demonstrate the presence of two types of commensurate, registered water monolayers with different densities at the RuO2(110)/bulk-water (0.1 M NaOH solution) interface with off-specular, oxygen crystal truncation rods. At anodic potentials (close to oxygen evolution), the extraneous water layer and the surface hydroxide layer form a bilayer with O-H-O bond distances similar to that of ice X. At cathodic potentials, the water molecules converted from the bridging OH molecules form a low-density water layer. 相似文献
84.
High-resolution specular x-ray reflectivity of the mica(001)-water interface under ambient conditions reveals oscillations in water oxygen density in the surface-normal direction, giving evidence of interfacial water ordering. The spacings between neighboring water layers in the near-surface, strongly oscillatory region are 2.5(2)-2.7(2) A, approximately the size of the water molecule. The density oscillations extend to about 10 A above the surface and do not strictly maintain a solvent-size periodicity as that in interfacial liquid metal and hard-sphere molecular liquids. We interpret this oscillatory density profile of the interfacial water as due to the "hard-wall" effect of the molecularly smooth mica surface. 相似文献
85.
Nayfeh AH Abdelrahman WG Nagy PB 《The Journal of the Acoustical Society of America》2000,108(4):1496-1504
An exact treatment of the propagation of axisymmetric waves in coaxial anisotropic assembly of piezoelectric rod systems is presented. The rod system consists of an arbitrary number of coaxial layers, each possessing transversely isotropic symmetry properties. The treatment, which is based on the transfer matrix technique, is capable of deriving the dispersion relations for a variety of situations. These include the case of a single rod system that is either embedded in an infinitely extended solid or fluid host or kept free. The procedure is also adapted to derive approximate solutions for the cases of a periodic fiber distribution in a matrix material, which model unidirectional fiber-reinforced composites. The results are numerically illustrated for a widely used piezoelectric-polymer composite. It is seen that piezoelectric coupling can significantly change the morphology of the dispersive behavior of the composite. 相似文献
86.
Volodin A Ahlskog M Seynaeve E Van Haesendonck C Fonseca A Nagy JB 《Physical review letters》2000,84(15):3342-3345
Coiled carbon nanotubes were produced catalytically by thermal decomposition of hydrocarbon gas. After deposition on a silicon substrate, the three-dimensional structure of the helix-shaped multiwalled nanotubes can be visualized with atomic force microscopy. Helical structures of both chiralities are present in the nanotube deposits. For larger coil diameters ( >170 nm), force modulation microscopy allows one to probe the local elasticity along the length of the coil. Our results agree with the classical theory of elasticity. Similar to the case of straight nanotubes, the Young modulus of coiled multiwalled nanotubes remains comparable to the very high Young modulus of hexagonal graphene sheets. 相似文献
87.
Kneller JM Soto RJ Surber SE Colomer JF Fonseca A Nagy JB Pietrass T 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2000,147(2):261-265
In a typical continuous-flow optical pumping setup, the chemical shift of xenon in the adsorbed phase depends on the gas flow rate due to warming of the sample surface by the gas stream. Calibration of the system using the (207)Pb resonance of solid lead nitrate is necessary to determine the actual sample temperature. Optimum pulse repetition rates are strongly affected by gas flow and spin-lattice relaxation rates. The interplay of flow and pulse repetition rate alters signal intensity ratios and may lead to the complete suppression of signals. 相似文献
88.
Vikram Basava Broc Flores Matthew Giovine Thomas Licisyn Katelyn Walck Walter Boyko 《Journal of carbohydrate chemistry》2013,32(7):389-400
The addition of benzenesulfinic acid to glycals was investigated under various conditions, and optimized yields of the glycosyl phenylsulfone products were obtained in the presence of tin tetrachloride as a catalyst. Double bond shift (Ferrier rearrangement) occurred in all cases except amicetal, which lacks a substituent at the allylic carbon. Glycosylation of benzenesulfinic acid with 1,2-dibromides was carried out using silver triflate as the promoter, and gave sulfinate esters as products by reaction at oxygen rather than at sulfur. The sulfinate esters were obtained as mixtures of stereoisomers at the stereogenic sulfur atom. Trapping of the sulfinates with carboxylate nucleophiles was observed during attempted oxidation with MCPBA. 相似文献
89.
Mohd Rushdi Abu Bakar Zoltan Kalman Nagy Christopher David Rielly 《Journal of Thermal Analysis and Calorimetry》2010,99(2):609-619
A combination of differential scanning calorimetry and hot-stage microscopy with image analysis has been used to investigate
the polymorphism of sulfathiazole. The use of light intensity profiles obtained from the HSM images, as an alternative way
to present results of the HSM analysis, was found to be useful in describing and verifying thermal events. The approach provides
a unique insight into the polymorphic transformations and thermal behaviour exhibited by this compound. The results of the
experiments show that sulfathiazole tends to crystallise as mixtures of polymorphs, even though the literature methods for
producing pure polymorph were followed. 相似文献
90.