Segregation in Titanium Dioxide Co‐Doped with Indium and Niobium

This work reports the effect of oxygen activity on surface segregation for TiO₂ co‐doped with two cations, indium and niobium (0.076 at.% In + 0.103 at.% Nb). In this work, we studied the effect of annealing at 1273 K in the gas phase of controlled oxygen activity on surface segregation of both ions. The applied oxygen activity included pure oxygen, p(O₂) = 100 kPa, and argon, p(O₂) = 10 Pa. The segregation‐induced concentration gradients were determined using both secondary ion mass spectrometry and X‐ray photoelectron spectroscopy. The obtained results indicate that annealing of the studied TiO₂ specimens in argon results in cooperative segregation of both ions leading to the formation of a surface structure involving comparative concentrations of both cations. However, annealing in oxygen results in preferential segregation of indium leading to the formation of a In₂TiO₅‐type surface structure. The obtained results are considered in terms of the effect of multicomponent segregation on processing of the surface layer with controlled properties that are desired for specific applications. The present work indicates that oxygen activity may be used as the parameter in surface engineering of the solid solution.     

Properties of the Ti<Subscript>40</Subscript>Zr<Subscript>10</Subscript>Cu<Subscript>36</Subscript>Pd<Subscript>14</Subscript> BMG Modified by Sn and Nb Additions

The results of investigation of the influence of additions of 2 and 3 at.% of Sn and simultaneously of Sn and 3 at.% Nb on microstructure and properties of the bulk metallic glasses of composition (Ti₄₀Cu_36?x Zr₁₀Pd₁₄Sn _x )_100?y Nb _y are reported. It was found that the additions of Sn increased the temperatures of glass transition (T _g), primary crystallization (T _x ), melting, and liquidus as well as supercooled liquid range (ΔT) and glass forming ability (GFA). The nanohardness and elastic modulus decreased in alloys with 2 and 3 at.% Sn additions, revealing similar values. The 3 at.% Nb addition to the Sn-containing amorphous phase decreased as well all the T _g, T _x , T _L, and T _m temperatures as ΔT and GFA; however, relatively larger values of this parameters in alloys containing larger Sn content were preserved. In difference to the previously published results, in the case of the amorphous alloys containing small Nb and Sn additions, a noticeable amount of the quenched-in crystalline phases was not confirmed, at least of the micrometric sizes. In the case of the alloys containing Sn or both Sn and Nb, two slightly different amorphous phase compositions were detected, suggesting separation in the liquid phase. Phase composition of the alloys determined after amorphous phase crystallization was similar for all compositions. The phases Cu₈Zr_3, CuTiZr, and Pd₃Zr were mainly identified in the proportions dependent on the alloy compositions.     

冷弯型钢抗弯框架的延性研究

对地震作用下抗弯框架中冷弯型钢构件的选用进行研究。冷弯型钢构件的主要不足是薄壁单元的平面外刚度很小,延性也很差。抗弯框架的主要构件为梁、柱及梁柱节点。在抗震框架中,梁能提供足够的延性,而其他单元主要受弹性域的限制。研究了带弯曲翼缘的新型冷弯型钢梁性能,并与传统钢梁比较。新型梁柱节点包含一个节点板,它能限制节点传递来的力引起的平面外变形。通过有限元分析,研究了新型冷弯型钢梁及梁柱节点的性能。结果表明:新型梁构件及节点的延性比传统冷弯型钢框架单元更好。     

User satisfaction modeling framework for automotive audio interfaces

Currently the research on product satisfaction is evolving to integrate pleasure and delight alongside other, more traditional needs. Pleasure and delight are emotional and hedonic benefits experienced by the user when interacting with the product. Thus, user satisfaction models have to deal with high complexity of product properties that collectively contribute to satisfaction. The formulation of these models has to include not only a proper taxonomy, but also the organization of such properties in categories and their relation to well defined satisfaction dimensions. Successful models would help to find out the most effective technical and design specifications (engineering parameters) that give shape to specific attributes of design, sometimes called “brand feelings”, defined in accordance with the business strategy. The objective of this paper is to present a user satisfaction modeling framework that deals with the complexity of an in-car user interface, namely the audio one. The proposed framework defines three distinct types of product properties: engineering parameters (P), perceived product attributes (A) and satisfaction dimensions (D) and presents a methodology to link the perceived product attributes (A) to satisfaction dimension (D).     

Visible Frequency Thin Film Photonic Crystals from Colloidal Systems of Nanocrystalline Titania and Polystyrene Microspheres

This work describes a simple and novel ceramic processing technique to form periodic ordered structures in ceramic materials with a uniform pore size distribution. This material shows photonic gaps at visible/near-IR wavelengths. Monodisperse colloidal polystyrene microspheres are self-organized into a crystalline structure of close-packed spheres in a suspension of nanocrystalline titania. The nanoparticle titania fills the intersphere region simultaneously during colloidal crystallization. Removal of the polystyrene microspheres by calcination at a temperature of 520°C results in a periodic porous structure with a high refractive index background material. Crystals having ordered regions, a few millimeters across with typical grain sizes of 50–70 μm, are grown as thin films on substrates including glass and silicon. Optical reflectivity measurements indicate peaks at the stop band wavelengths that scale with the pore size. Visual inspection and optical microscopy reveal uniform colored regions for crystals with periodicity comparable to visible wavelengths. Despite the presence of cracks resulting from drying and heat treatment as well as numerous grain boundaries, optical characterization clearly demonstrates a photonic band gap. Reflectance peaks due to a pseudogap can be shifted by application of high pressure. In the following sections we will describe the experimental procedure and discuss optical reflectance and transmission measurements that can reveal information about the crystals, namely, the lattice constant, the refractive index, and the filling fraction of the background material.     

Ductile moment-resisting frames using cold-formed steel sections: An analytical investigation

This paper presents an investigation on the potential use of cold-formed steel sections (CFS sections) in moment-resisting frames (MRFs) for seismic applications. The main limitation of CFS sections is the low out-of-plane stiffness of their thin-walled elements which leads to low ductility. The main components of MRFs are beams, beam-column connections and columns. In earthquake resistant MRFs, the beams are designed to provide considerable ductility, whereas the other elements are mainly limited to their elastic range. The performance of a new shape of CFS beam with curved flange is examined analytically and compared with that of conventional shapes. The proposed beam-column connections include through plates which potentially limit the out-of-plane action of the forces transferred through the connections. The behaviour of both individual CFS beam sections and CFS beam-column connections is studied by means of finite element analysis (FEA). The results of the analyses show that the new beam cross sections and connections exhibit a good ductile behaviour, something which cannot be achieved by conventional cold-formed frame elements.     

A deterministic Wigner approach for superposed states

Journal of Computational Electronics - The Wigner formalism is a convenient way of describing quantum mechanical effects through a framework of distribution functions in phase space. Currently,...