Ag/Ag2S–TiO2 composite film formed using dual phase Ag/Ag2O layer as a sulfurized layer for enhanced photocatalytic activity

The Ag/Ag₂S–TiO₂ composite films were synthesized through vulcanizing sputtering Ag/Ag₂O dural-phase template capping layer on the TiO₂ film. After hydrothermal vulcanization using thiourea as a sulfur precursor, the initially decorated Ag₂O layer transformed into the Ag₂S. The surface morphology of the continuous block structure of the Ag/Ag₂S composite layer gradually shrinks to form irregular island grains dispersed on the surface of the composite film, with vulcanization reaction duration increased from one to 3 h. The light absorption ability of the Ag/Ag₂S–TiO₂ composite film was enhanced substantially compared to the TiO₂ film because of the surface plasmon resonance effect from the Ag particles and the narrow energy band of the Ag₂S. Among various surface morphologies of the Ag/Ag₂S–TiO₂ composite films, the irregular island Ag/Ag₂S grains-decorated TiO₂ composite film presents superior photoelectrochemical and photocatalytic degradation performances than the composite films consisting of continuous block and spider-web structure of the Ag/Ag₂S decorated layers. The synergistic effects of surface plasmon resonance, Ag pathway between the semiconductors, and Z-scheme charge transfer mechanism explain the high-efficiency photocatalytic activity of the Ag/Ag₂S–TiO₂ composite films.     

Effect of oxide shells on the magnetic and magnetotransport characteristics of oxidized FeCoZr nanogranules in Al2O3

The paper reports on the results of a comparative study of magnetic and magnetotransport properties of granular nanocomposite films FeCoZr-Al₂O₃ synthesized in pure Ar and Ar + O sputtering atmosphere. Effects of oxygen incorporation on the temperature and magnetic field dependencies of magnetization and electrical resistance of the films are discussed with respect to the “core-shell” structure formation. Peculiarities of coercive force variation with temperature are analyzed and discussed.     

Atomic force microscopy study of Mo (110) surface topology after high temperature homoepitaxy

In this paper we report experimental results on investigation of Mo (110) single crystals surface topology carried out using AFM technique after high-temperature homoepitaxy within the frame of deposition rates 1-40 ML/s and in the interval of substrate temperatures 1900 °C-2300 °C. The systems of atomically flat steps on the surface of single crystal samples were observed. Typical height of the steps was in the range 1-4 of (110) parallel lattice plane spacing, with width being about 50-70 nm. High temperature homoepitaxy of Mo leads to formation of micro-crystals with dimensions up to 150 μ in width and few micrometres in height. Huge monatomic steps up to 5-10 μ in width were observed on flat (110) Mo micro-crystal planes slightly declined to the substrate surface. The root-mean-square (RMS) roughness of the micro-crystal surfaces achieves the values of 0.2 nm which is determined by the presence of monoatomic steps. The residual pattern of spiral growth was also observed on the top of (110) micro-crystal surfaces.     

UV Raman spectroscopic study on the surface phase of ZrO2 modified with Nd2O3

The Nd₂O₃ modified ZrO₂ was synthesized using two methods of co-precipitation (Nd-ZrO₂) and wet impregnation (Nd/ZrO₂). The surface and bulk crystalline phases of Nd₂O₃ modified ZrO₂ were investigated by using UV Raman spectroscopy, visible Raman spectroscopy, and X-ray diffraction (XRD). It is observed that the tetragonal phase in the surface region of Nd-ZrO₂ was not effectively stabilized by Nd₂O₃, as Nd₂O₃ is mainly present in the bulk of Nd-ZrO₂. However, in Nd/ZrO₂, it is found that with the impregnation of 0.5 mol% Nd₂O₃ on ZrO₂, the surface tetragonal phase of Nd/ZrO₂ can be stabilized even after calcination at 700 °C. The UV Raman results indicate that a disordered structure, or intermediate structure, which is involved in the transition from the tetragonal to the cubic phase, is formed at the surface region of Nd/ZrO₂. The formation of the aforementioned intermediate structure inhibits the phase transition from tetragonal to monoclinic in the surface region of Nd/ZrO₂. Furthermore, it is observed that the mixed tetragonal and monoclinic phases in the surface region of ZrO₂ which has been impregnated with Nd₂O₃ can also be stabilized after calcination at 700 °C. This work provides a simple method for controlling the surface phase of ZrO₂ at high temperatures.     

Rural Studio: Incarnations of a Design-and-Build Programme

Catering for the needs of an impoverished rural community in Alabama through its design-and-build activities, Rural Studio leads the way internationally as a university-affiliated architecture programme with a social remit. Guest-Editor Michael Hensel describes how the initiative has grown and developed since it was first established over two decades ago, in 1993, by Samuel Mockbee for students from Auburn University. The realisation of tens of houses and community projects have not only helped to reshape the local environment, but with the more recent strategic approach advanced under Andrew Frear's directorship more long-term projects have been launched and greater emphasis has been placed on the responsible local sourcing of materials, energy and food.     

Superhydrophilic anatase TiO2 film with the micro- and nanometer-scale hierarchical surface structure

Nanosized anatase TiO₂ film on the ITO glass has been fabricated via spin coat process, with sodium dodecylbenzenesulfonate modified TiO₂ nanoparticles, which is synthesized by a sol-hydrothermal method, and also characterized mainly by means of field emission scanning electron microscopy (FESEM). The results show that the as-prepared anatase TiO₂ film exhibits superhydrophilic characteristic although it is not exposed to ultraviolet irradiation. The high roughness resulting from hierarchical surface structure is responsible for its superhydrophilicity. This work would provide a new route to fabricate newly nanostructured semiconductor films.     

Neodymium conversion layers formed on zinc powder for improving electrochemical properties of zinc electrodes

Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH)₂ dissolved in the electrolyte.     

The influence of the additives composition and concentration on the properties of SnOx thin films used in photocatalysis

The aim of this study is to investigate the influence of different organic additives on the surface properties of SnO_x thin films used for photocatalytic degradation of methylene blue. The films were obtained by anodic oxidation of tin substrate in electrolyte solutions containing green additives based on hydrophobic and hydrophilic maleic anhydride copolymers. The hydrophobic copolymer leads to the formation of thin films with increased specific area which generates a larger interfacial area between the layers and the dye solution. The consequence is an improvement in the photocatalytic efficiency: up to 16% compared to less than 5% for samples electrodeposited without polymer. The hydrophilic copolymer presence in the electrolyte solution leads to higher grain size and lower surface energy which significantly reduce the photocatalytic properties of the layers. The use of copolymers can be a tool for enhancing the surface roughness and film's wettability and thus the photodegradation efficiency.     

Towards animating ray-traced volume visualization

Ray-tracing volumetric data may take several minutes to compute a single image from a fixed viewpoint. We present techniques that generate approximate ray-traced volumetric images in less than one second per image, after a lengthy initialization process is performed. These approximate images are based on methods that interpolate data sampled at locations on a sphere.