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91.
G.?PolettiEmail author F.?Orsini A.?Raffaele-Addamo C.?Riccardi E.?Selli 《Pramana》2004,62(4):911-921
Some selective cold plasma processing modify specific surface properties of textile polymeric materials such as their dyeability,
wettability and hydrorepellence. To correlate the sample surface changes with the acquired surface properties allows one to
obtain information on the chemical and physical processing involved in plasma treatment. In this work, atomic force microscopy
(AFM) has been applied to investigate the morphological and topographical surface modifications induced by RF cold plasma
processing of poly(ethyleneterephthalate) (PET) fabrics. Rms surface roughness and surface area of the samples are measured
before and after the treatments. The morphology changes have been analysed as a function of the treatment time and air gas
pressure. Measurements have been performed also using plasmas produced by different gases such as He, Ar, SF6 and CF4. The PET shows different behaviour with different gas plasmas. In the case of air, He and Ar gases the sample surface modifications
seem to be mainly due to etching effects, while the fluorine atoms grafting probably is responsible for surface rearrangement
process using SF6 and CF4 gases. As a consequence different surface properties are produced in the plasma treated samples.
Article presented at the International Conference on the Frontiers of Plasma Physics and Technology, 9–14 December 2002, Bangalore,
India. 相似文献
92.
93.
Bonardi M Birattari C Groppi F Gini L Ghioni A Mainardi HS Arginelli D Gallorini M Rizzio E Sabbioni E 《Annali di chimica》2003,93(4):363-372
In this paper are presented the production methods for very "high specific activity" radionuclides (HSA-RN) of vanadium, manganese and thallium which have been developed in our laboratories for labelling different chemical forms of these elements present in the echo-systems in ultra-trace amounts, for metallo-toxicological and bio-kinetic studies. Use was made of both cyclotron and thermal nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. This kind of radionuclide is named No Carrier Added, NCA, and his specific activity, As is very high and can reach values close to the theoretical Carrier Free one, CF. The experimental determination of specific activity, chemical and radiochemical purities is mandatory for all these kinds of applications. 相似文献
94.
Traversa Enrico Di Vona Maria Luisa Licoccia Silvia Sacerdoti Michele Carotta Maria Cristina Gallana Massimiliano Martinelli Giuliano 《Journal of Sol-Gel Science and Technology》2000,19(1-3):193-196
Pure, 5 at%, and 10 at% Ta- or Nb-doped TiO2 nanosized powders were prepared by the sol-gel method. The powders heated to 400°C have the crystalline anatase structure. While the pure TiO2 powder heated to 850°C has the rutile structure, the addition of Ta and Nb inhibited the anatase-to-rutile phase transformation at this temperature. Ta was soluble in the titania lattice up to the concentration of 10 at%, while the solubility of Nb was 5 at%. Thick films were fabricated with these powders by screen printing technology and then fired at 650°C and 850°C for 1 h. SEM observations showed that the anatase-to-rutile phase transformation induces a grain growth of about one order of magnitude for pure TiO2. The addition of Ta and Nb is effective to keep the TiO2 grain size at the nanometric level even at 850°C. Conductance measurements showed that a good gas response is observed only for the nanostructured titania-based films. The CO response of these materials is only slightly affected by humidity. 相似文献
95.
Salvatore Giuffrida Guglielmo G. Condorelli Lucia L. Costanzo Giorgio Ventimiglia Raffaella Lo Nigro Maria Favazza Enrico Votrico Corrado Bongiorno Ignazio L. Fragalà 《Journal of nanoparticle research》2007,9(4):611-619
Liquid Phase Photo-Deposition (LPPD) technique has been used to obtain both colloidal particles and thin films of metallic
and chloride nickel from solutions of only precursor Ni(acac)2 (acac=2,4-pentandionato). Metallic nickel was obtained from ethanol solutions by direct nickel(II) photoreduction at 254 nm
and by acetone sensitised reaction at 300 nm. In this latter process the rate was higher than in the first one. NiCl2 was formed from CCl4 solution by a solvent-initiated reaction. TEM analysis, performed on colloidal particles of nickel, showed that their dimensions
are in the range 2–4 nm. The films did not present carbon contamination and were characterized by AFM, XPS and GIXRD. Metallic
films consisted of particles of 20–40 nm that are the result of the aggregation of smaller crystallites (4–5 nm). Larger agglomerations
(around 200 nm) have been observed for NiCl2 films. 相似文献
96.
Calculations of the kinetic energy distributions of electrons ejected from plane metal surfaces by Auger neutralization of slow monoatomic ions are reported. A many body theory is used that includes both the band structure of the target material and the Fermi singular response of metal electrons (to the sudden neutralization of the projectile). Application is made to experiments of electron emission from polycrystalline Al by Ar+-ions, at varying incident energies and angles. Adjustment of the broadening parameters of the distribution of shake-up electrons leads to excellent agreement between the theory and the measurements. 相似文献
97.
98.
99.
Curcumin, a chemical compound present in the well-known Indian spice turmeric, has uses in many different fields ranging from
medicinal chemistry to the dye industry. Its poor water solubility, though, makes Curcumin difficult to handle, making it
less appealing for potential uses. The principal aim of this work is to perform a computational study of the structural and
electronic properties of Curcumin {IUPAC name: 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione} in several solvents,
and a comparison with experimental data. Rotameric equilibria, vibrational and thermochemical analysis, and electronic absorption
spectra (with ab initio and semi-empirical methodologies) have been studied, both in vacuum and in three selected solvents. Different computational
techniques have been applied and the results compared. Combined approaches resulted in very satisfactory results. Interesting
results have emerged, which suggest subsequent investigations about the nature of the excited states and potential derivatives
of Curcumin that possibly have non-linear optical applications, as a π-core for innovative materials in laser engineering and photonics. 相似文献
100.