Classical q-deformed dynamics

On the basis of the quantum q-oscillator algebra in the framework of quantum groups and non-commutative q-differential calculus, we investigate a possible q-deformation of the classical Poisson bracket in order to extend a generalized q-deformed dynamics in the classical regime. In this framework, classical q-deformed kinetic equations, Kramers and Fokker-Planck equations, are also studied.     

Synthesis and characterization of a novel magnetic carrier with its composition of Fe3O4/carbon using hydrothermal reaction

In this study, a simple method to prepare a novel magnetic carrier based on carbon matrix has been built by heating the aqueous solution of glucose and oleic acid-stabilized Fe₃O₄ nanoparticle at 170 °C for 3 h. The results show that the surface hydrophobic modification of Fe₃O₄ nanoparticle is necessary for the successful synthesis of Fe₃O₄/C nanocomposition, and a possible formation mechanism of Fe₃O₄/C nanocomposition was presented. The influence of the reaction parameters such as the concentration of oleic acid-stabilized Fe₃O₄ nanoparticle, the reaction time, etc. on the product was also investigated. In the typical reaction (2.5 g/L of oleic acid-stabilized Fe₃O₄ nanoparticle, 0.5 M of glucose), Fe₃O₄/C nanocompositions with the average diameter in the range 100–200 nm were obtained and its saturation is 12.4 emu/g. In order to characterize Fe₃O₄/C nanocompositions, XPS, XRD, FT–IR, and Mössbauer spectra were employed.     

Dependence of band structures on stacking and field in layered graphene

Novel systems of layered graphene are attracting interest for theories and applications. The stability, band structures of few-layer graphite films, and their dependence on electric field applied along the c-axis are examined within the density functional theory. We predict that those of Bernal type and also rhombohedral type tri- and tetra-layer graphite films exhibit stability. Rhombohedral-type systems, including AB-bilayer, show variable band gap induced by perpendicular electric fields, whereas the other systems, such as the Bernal-type films, stay semi-metallic.     

Characterisation under static and dynamic conditions of commercial activated carbons for their use in wastewater plants

The use of activated carbon for removing organic contaminants in fixed beds is increasing. This is a dynamic process in which the kinetics plays an important role. The aim of this paper is to get more insight into adsorption of p-nitrophenol (PNP) in activated carbon under equilibrium and dynamic conditions. Five commercial activated carbons were studied. The analysis carried out were PNP adsorption isotherms in aqueous solution at 20 °C, N₂ at 77 K isotherms, FT-IR and PNP adsorption under dynamic conditions. The results indicate that the external porous affinity toward the organic contaminants determines in large extent the adsorbents behaviour under dynamic conditions.     

Differential geometry of the quantum 3-dimensional space

A Hopf algebra structure of the extended three-dimensional quantum space is defined. A differential algebra of the extended three-dimensional quantum space is introduced and its Hopf algebra structure is explicitly given. The (undeformed) Lie algebra of three dimensional quantum space is obtained.     

Morphology and electronic structure of nanostructured carbon films embedding transition metal nanoparticles

Inclusions of metals in the growth process of carbon cluster assembled materials (ns-C) induce modifications in the structural and electronic properties of the material. A novel pulsed microplasma cluster source (PMCS) is able to deliver highly intense, collimated and stable beams suitable for producing bulk quantities of cluster-assembled nanocomposite films. Loading of metal nanoparticles into carbon cluster based films is obtained either by mixing a gas phase metallorganic compound with the carrier gas (He) before entering into the source (for example molybdenum (V) isopropoxide), or by using a double component sputtering target (metal (Ti, Ni)/graphite). The study of film morphology on nanometer scale, carried out by transmission electron microscopy (TEM), reveals the dispersion in a ns-C matrix of metallic particles and, in the case of molybdenum containing films, also of carbide particles. Spatially resolved ultraviolet photoemission spectroscopy confirms the segregation of metal particles and exhibits evident anisotropy in the Mo:ns-C films, mainly ascribable to the formation of carbide nanoparticles.     

Spin filter,spin amplifier and spin diode in graphene nanodisk

Graphene nanodisk is a graphene derivative with a closed edge. The trigonal zigzag nanodisk with size N has N-fold degenerated zero-energy states. It can be interpreted as a quantum dot with an internal degree of freedom. The ground state of nanodisk is a quasi-ferromagnet, which is a ferromagnetic-like state with a finite but very long life time. We investigate spin-filter effects in the system made of nanodisks and leads. A novel feature of the nanodisk spin filter is that its spin can be controlled by the spin current. We propose some applications for spintronics, such as spin memory, spin amplifier and spin diode. It is argued that a spin current is reinforced (rectified) by feeding it into a nanodisk spin amplifier (diode). Graphene nanodisk would be a promising candidate of future electronic and spintronic nanodevices.     

Rectifying properties and photoresponse of CVD diamond p(i)n‐junctions

The current–voltage characteristics and photoresponse of mesa structured {111}‐oriented homoepitaxial CVD diamond p(i)n‐junctions with different intrinsic layer thickness are investigated. When a sufficiently thick intrinsic layer is present, a rectification ratio of 10⁸ at ±10 V could be obtained. Good rectifying diodes show a high photoresponse ratio between 210 nm (above bandgap) and 500 nm (below bandgap), making them suitable for UV detection purposes. The results are compared with similar measurements carried out on polycrystalline CVD diamond pn‐junctions.

     

Structure and gas-barrier properties of amorphous hydrogenated carbon films deposited on inner walls of cylindrical polyethylene terephthalate by plasma-enhanced chemical vapor deposition

The influence of radio-frequency (RF) power on the structure and gas permeation through amorphous hydrogenated carbon films deposited on cylindrical polyethylene terephthalate (PET) samples is investigated. The results show that a higher radio-frequency power leads to a smaller sp³/sp² value but produces fewer defects with smaller size. The permeability of PET samples decreases significantly after a-C:H deposition and the RF only exerts a small influence. However, the coating uniformity, color, and wettability of the surface are affected by the RF power. A higher RF power results in to better uniformity and it may be attributed to the combination of the high-density plasma and sample heating.