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931.
Roberto Beneduci 《International Journal of Theoretical Physics》2011,50(12):3724-3736
In the present paper, we review some recent results about commutative positive operator valued measures (POVMs) and single
out some open problems. We introduce a conjecture about the extension of some recent results and prove some important consequences
of such conjecture. In particular, we prove that it implies the universal character of some of the mathematical objects we
introduce, i.e., the fact that they do not depend on the POV measure we are considering. We analyze the relevance of this
result. Finally, we point out that some of the results we present admit a constructive proof and we show the relevance of
this fact to the theory of commutative POV measures. 相似文献
932.
933.
In this work, the influence of synthesis parameters on the synthesis efficiency of tin oxide nanomaterials was studied by
using the carbothermal reduction method in a sealed tube furnace. The parameters were the starting material, temperature and
time of synthesis as well as the gas flux. The starting material was tin dioxide mixed with carbon black in a molar proportion
of 1.5:1 and 1:1. The temperature range was from 950 to 1,125 °C with a step of 25 °C, and the synthesis times used were 15,
30, 45, 60, 75, 90, and 120 min. Using optimum values of the above parameters, the gas flux was changed to verify its influence.
After completion of the syntheses, we found a grayish-black material inside the tube which was characterized by X-ray diffraction
and scanning electron microscopy. The results showed that the collected material is composed of nanobelts (with width around
60 nm) and disks that grew preferentially in the SnO phase. A model based on the oxide vapor pressure was proposed to evaluate
the efficiency of the process, and the results showed good agreement between experimental data and the proposed model. Based
on the results obtained, the best conditions to obtain a homogeneous material with 95% efficiency is using a starting material
in the molar proportion Sn:C of 1.5:1, a temperature of 1,132 °C for 75 min, and a N2 gas flux of 80 sccm. 相似文献
934.
Hosseini M Ganjali MR Tavakoli M Norouzi P Faridbod F Goldooz H Badiei A 《Journal of fluorescence》2011,21(4):1509-1513
A novel and simple fluorescence enhancement method for selective pyrophosphate(PPi) sensing was proposed based on a 1:1 metal
complex formation between bis(8-hydroxy quinoline-5-solphonat) chloride aluminum(III) (Al(QS)2Cl), (L) and PPi in aqueous solution. The linear response range covers a concentration range of 1.6 × 10−7 to 1.0 × 10−5 mol/L of PPi and the detection limit of 2.3 × 10−8 mol/L. The association constant of L-PPi complex was calculated 2.6 × 105 L/mol. L was found to show selectively and sensitively fluorescence enhancement toward PPi over than I3-, NO3-, CN−, CO32−, Br−, Cl−, F−, H2PO4− and SO42−, which was attributed to higher stability of inorganic complex between pyrophosphate and L. 相似文献
935.
Yu -Qi Li Xiao -Ming Xu Hui -Jun Ge 《The European Physical Journal A - Hadrons and Nuclei》2011,47(5):65
We divide the cross-section for a meson-meson reaction into three parts. The first part is for the quark-interchange process,
the second for quark-antiquark annihilation processes and the third for resonant processes. Master rate equations are established
to yield time dependence of fugacities of pions, rhos, kaons and vector kaons. The equations include cross-sections for inelastic
scattering of pions, rhos, kaons and vector kaons. Cross-sections for quark-interchange-induced reactions, that were obtained
in a potential model, are parametrized for convenient use. The number densities of π and ρ (K and K
* are altered by quark-interchange processes in equal magnitudes but opposite signs. The master rate equations combined with
the hydrodynamic equations for longitudinal and transverse expansion are solved with many sets of initial meson fugacities.
Quark-interchange processes are shown to be important in the contribution of the inelastic meson-meson scattering to the evolution
of mesonic matter. 相似文献
936.
Anatoly F. Nastoyashchiy 《Journal of Russian Laser Research》2011,32(3):238-246
We propose a simple target in the form of a miniature torus, in which the heavy shell is used to confine the plasma spread,
for a solution of the laser-fusion problem. We achieve a significant decrease of heat losses using an external magnetic field
and/or as a result of a self-sustaining magnetic field that is generated in the plasma. We formulate the conditions and determine
the energy of the laser pulse (or of a beam of fast charged particles) required to ignite a thermonuclear DD reaction and
obtain a positive energy yield. We show that the stopping range of α-particles does not exceed the small radius of the torus
within a broad range of the plasma and magnetic-field parameters. 相似文献
937.
Andrew K. Johnson Jozef Kaczor Hongmei Han Maninder Kaur Guoxin Tian Linfeng Rao You Qiang Andrzej J. Paszczynski 《Journal of nanoparticle research》2011,13(10):4881-4895
The creation of multifunctional nanomaterials by combining organic and inorganic components is a growing trend in nanoscience. The unique size-dependent properties of magnetic nanoparticles (MNPs) make them amenable to numerous applications such as carriers of expensive biological catalysts, in magnetically assisted chemical separation of heavy metals and radionuclides from contaminated water sources. The separation of minor actinides from high-level radionuclide waste requires a sorbent stable in acidic pH, with ease of surface functionalization, and a high capacity for binding the molecules of interest. For the described experiments, the MNPs with 50 nm average size were used (size distribution from 20 to 100 nm and an iron content of 80–90 w/w%). The MNPs that have been double coated with an initial silica coating for protection against iron solubilization and oxidation in nitric acid solution (pH 1) and a second silica/polymer composite coating incorporating partially imbedded poly(allylamine) (PA). The final product is magnetic, highly swelling, containing >95% water, with >0.5 mmol amines g?1 available for functionalization. The amine groups of the magnetic resin were functionalized with the chelating molecules diethylenetriaminepentaacetic acid (DTPA) and N,N-dimethyl-3-oxa-glutaramic acid (DMOGA) for separation of minor actinides from used nuclear fuel. 相似文献
938.
Sagar E. Shirsath R.H. KadamAnil S. Gaikwad Ali GhasemiAkimitsu Morisako 《Journal of magnetism and magnetic materials》2011,323(23):3104-3108
Sintering temperature and particle size dependent structural and magnetic properties of lithium ferrite (Li0.5Fe2.5O4) were synthesized and sintered at four different temperatures ranging from 875 to 1475 K in the step of 200 K. The sample sintered at 875 K was also treated for four different sintering times ranging from 4 to 16 h. Samples sintered at 1475 K have the cubic spinel structure with a small amount of α-Fe2O3 (hematite) and γ-Fe2O3 (maghemite). The samples sintered at≤1275 K do not show hematite and maghemite phases and the crystals form the single phase spinel structure with the cation ordering on octahedral sites. Particle size of lithium ferrite is in the range of 13-45 nm, and is depend on the sintering temperature and sintering time. The saturation magnetization increased from 45 to 76 emu/g and coercivity decreases from 151 to 139 Oe with an increase in particle size. Magnetization temperature curve recorded in ZFC and FC modes in an external magnetic field of 100 Oe. Typical blocking effects are observed below about 244 K. The dielectric constant increases with an increase in sintering temperature and particle size. 相似文献
939.
940.