An optimal iteration method with application to the Thomas-Fermi equation

The aim of this paper is to introduce a new approximate method, namely the Optimal Parametric Iteration Method (OPIM) to provide an analytical approximate solution to Thomas-Fermi equation. This new iteration approach provides us with a convenient way to optimally control the convergence of the approximate solution. A good agreement between the obtained solution and some well-known results has been demonstrated. The proposed technique can be easily applied to handle other strongly nonlinear problems.     

Structural and thermoluminescence properties of undoped and Fe-doped-TiO<Subscript>2</Subscript> nanopowders processed by sol–gel method

In this study, we report on the nanocrystalline powders of TiO₂ and Fe-doped TiO₂ (anatase and rutile phases) prepared by sol–gel method. The X-ray diffraction and Raman spectroscopy measurements indicated the presence of anatase or rutile phase in nanopowders. TEM micrographs showed 10 and 112 nm average particle sizes for anatase and rutile, respectively. Furthermore, their thermoluminescence properties were analyzed.     

Magnetic nanoparticles coated with polysaccharide polymers for potential biomedical applications

This study reports a two-steps route for obtaining magnetic nanoparticles–polysaccharide hybrid materials consisting of Fe₃O₄, NiFe₂O₄ and CuFe₂O₄ nanoparticles synthesis by coprecipitation method in the presence of a soft template followed by coating of ferrite nanoparticles of 8–10-nm size range with polysaccharide type polymers—sodium alginate or chitosan. Magnetic oxide nanoparticles and the corresponding hybrid materials were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy, atomic absorption spectroscopy (AAS), FTIR spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and specific surface area measurements. The vibrating sample magnetometry confirms the superparamagnetic properties of the synthesized ferrites and hybrids. Using this route, the percent of magnetic nanoparticles retained in chitosan-based hybrid materials is nearly double in comparison with that of sodium alginate–based materials. The biological activity tests on Escherichia coli ATCC 25922, Pseudomonas aeroginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Candida scotti microorganisms show the non-toxic properties of prepared hybrid materials.     

Thermal decomposition,kinetic study and evolved gas analysis of 1,3,5-triazine-2,4,6-triamine

The thermo-physical properties for four rock types (granite, granodiorite, gabbro, and garnet amphibolite) from room temperature to 1,173 K were investigated. Thermal diffusivity and specific heat capacity were measured using the laser-flash technique and heat flux differential scanning calorimetry, respectively. Combined with the density data, rock thermal conductivities were calculated. Rock thermal diffusivity and conductivity decrease as the temperature increases and approach a constant value at high temperatures. At room temperature, the measured thermal conductivity is consistently near or lower than the calculated conductivity using the mineral series model, which suggests that real thermal conduction is more complicated than is depicted in the model. Therefore, in situ measurement remains the best method for accurately obtaining thermal conductivity for rocks.     

The student distribution and the principle of maximum entropy

Summary The Student distribution is obtained by means of the principle of maximum entropy.     

基于顺丁烯二酸乙烯醋酸盐共聚物主链的热响应嫁接共聚物的合成和水溶液特性(英文)

pacc:7855K Materialsexhibitingthermallyinducedther mothickeningorgellingpropertiesinaqueousso lutions,i.e.presentingasubstantialviscosityin creaseuponheatingareratherexceptional,as mostfluidsarecharacterizedbythewell-known Arrheniusthermothinningbehavi…     

Osmium dioxide trifluoride OsO2F3: Synthesis and some properties

Osmium dioxide trifluoride, OsO₂F₃, has been synthesized thermally by the reaction of OsO₄ and OsF₆, or of OsOf₄ and OsO₃F₂. The yellow-green material is apparently isomorphous with the monoclinic α-phase of OsO₃F₂, and although the detailed structure is not known, the Raman spectrum indicates a fluorine bridged polymeric system is likely. OsO₂F₃ has either a small temperature independent susceptibility or a very small moment μ_eff < 0.25 μ_B, the uncertainty being due to the possibility of small amounts of paramagnetic impurity (<2%) in even the best samples prepared. The free molecule is polar, and disproportionates readily at temperatures required to obtain its mass spectrum. Magnetic susceptibilities are reported for OsO₃F₂, OsOF₄, OsO₂, OsF₅, and OsF₆, as well as the new molecule OsO₂F₃.     

The thermogravimetric behaviour of the vinyl acetate and α-methylstyrene copolymers of acrylonitrile

Journal of Thermal Analysis and Calorimetry - The influence of the copolymer nature, its comonomer content and the supermolecular structure on the thermal behaviour of the binary vinyl acetate...     

Thermal stability of new complexes bearing both acrylate and aliphatic amine as ligands

This paper reports the investigation of the thermal stability of a series of new complexes with mixed ligands of the type [M(en)(C₃H₃O₂)₂]·nH₂O ((1) M=Ni, n=2; (2) M=Cu, n=0; (3) M=Zn, n=2; en=ethylenediamine and (C₃H₃O₂)=acrylate anion). The thermal behaviour steps were investigated in a nitrogen flow. The thermal transformations are complex processes according to TG and DTA curves including dehydration, ethylenediamine elimination as well as acrylate thermolysis. The final products of decomposition are the most stable metal oxides except for complex (2) that generates metallic copper.