Growth and optical properties of Er,Yb:YAl3(BO3)4 crystal

Single crystal of erbium, ytterbium-codoped yttrium aluminum tetraborate Er,Yb:YAl₃(BO₃)₄(Er,Yb:YAB) has been grown by the flux method. The absorption spectrum in the visible and NIR regions of Er,Yb:YAl₃(BO₃)₄ crystal are measured at room temperature and fluorescence spectrum of Er,Yb:YAl₃(BO₃)₄ crystal are also measured at room temperature, excited by 976 nm laser. Not only the strong NIR emission peaks located at 1548 nm was observed, but also the visible up-conversion luminescence has been found. The specific heat of the Er/Yb:YAB crystal at room temperature is 0.81 J/g °C.     

Development of Measurement Facilities for Analyzing Petroleum Products

The question of developing measurement provisions for the parameters of petroleum products is considered. The main technical features of a KLAN-1 mobile laboratory unit for analyzing petroleum products intended for rapid analysis of fuel and lubricating materials in storage and on sale are provided.     

梯度功能材料热弹性应力的分析方法

本文介绍了近年来国外有关梯度功能材料热弹性应力问题的最新研究方法，并对其方法特点进行了评述．     

稀土材料新进展

叙述了稀土材料的新种类以及应用前景，并对国内稀土工业的现状及其存在的问题、国外稀土市场概况进行了综述，同时，展望了我国稀土材料的发展方向。     

Critical State of Granular Materials Based on the Sliding-Rolling Theory

By representing the assembly by a simplified column model, a constitutive theory was recently developed for a two-dimensional assembly of rods. This theory, referred to as the sliding-rolling theory, is extended in this paper to represent the triaxial stress-strain behavior of granular materials. The sliding-rolling theory provides a dilatancy rule and an expression for the slope of the line of zero dilatancy in the stress space. These rules are then combined with triaxial observations to provide a microstructural interpretation of the critical state of granular materials. According to the theory, the slope of the critical state line in the stress space depends on the interparticle friction angle and the degree of contact normal anisotropy. To verify the basic ideas of the sliding-rolling theory, numerical experiments are conducted using the discrete-element method on three-dimensional assemblies of spheres.     

Preparation and structure of fluorinated/non-fluorinated polyacrylate gradient emulsion blend film

The emulsion blend method, which is environmentally friendly and energy saving, was used to prepare a compositional gradient film of fluorinated/non-fluorinated polyacrylate in this paper. The size and glass-transition temperature (T_g) of the emulsion particles were designed to enhance the driving force of their selective congregation and promote the formation of gradient structure. The structures and surface properties of the obtained films were characterized. The results showed that when the fluorinated components have much smaller particle size and higher T_g than those of fluorine-free polyacrylate components, the gradient structures formed in the direction across the film thickness of the films. The concentration of the fluorinated component increased gradually from film-glass interface to film-air interface in the blend film, making the surface free energies of the two sides of the gradient film distinctively different.     

Metal‐containing Polymers via Electropolymerization

Electropolymerization represents a suitable and well‐established approach for the assembly of polymer structures, in particular with regard to the formation of thin, insoluble films. Utilization of monomers that are functionalized with metal complex units allows the combination of structural and functional benefits of polymers and metal moieties. Since a broad range of both electropolymerizable monomers and metal complexes are available, various structures and, thus, applications are possible. Recent developments in the field of synthesis and potential applications of metal‐functionalized polymers obtained via electropolymerization are presented, highlighting the significant advances in this field of research.     

Correlation between structural and optical properties of 30 nm and 60 nm lead sulfide nanowires

PbS nanowires with 30 nm and 60 nm diameter fabricated under the same condition of electrochemical deposition with sulfuric and oxalic anodic alumina membranes (AAM), respectively, have been successfully prepared in order to study their optical properties in relation to their size. Scanning electron microscopy indicates that the 60 nm PbS nanowire arrays have the same shape with the 30 nm. X-ray diffraction result shows that 60 nm PbS nanowires are crystalline and have a highly (200) preferential orientation like 30 nm ones. UV spectrum considers the nanowire size decrease as the absorption peak shifts to the blue. The quantum confinement effects compared between 30 nm and 60 nm PbS nanowire arrays were observed by the measurements of ultraviolet-visible absorption spectroscopy (UV-vis).     

A π-extended tetrathiafulvene derivative: Synthesis and photoluminescence properties

Solid-state emissive organic materials have received increasing attention due to their prospective applications in large-area. Here, a novel π-extended tetrathiafulvene derivative DPD with donor-π-donor structure has been newly developed to produce the prominent characteristic of aggregation-induced enhanced emission (AIEE) that exhibits higher fluorescence quantum efficiency in solid film compare to its solutions. The AIEE mechanism of DPD was studied in detail through photophysical investigations and can be dominant attributed to the formed excimer state of DPD and J-aggregates in solid state.     

Hematite solid and hollow spindles: Selective synthesis and application in gas sensor and photocatalysis

Hematite solid spindles and hollow spindles have been selectively synthesized by a template-free, economical hydrothermal method, using FeCl₃·6H₂O as the starting materials and NaOH as the homogeneous precipitant. XRD analyses indicated that the products consisted of α-Fe₂O₃. SEM and TEM measurements showed that the morphologies of products were in the shape of solid spindles and hollow spindles, respectively. A possible formation process based on the nucleation-oriented aggregation-recrystallization mechanism is proposed. Moreover, the as-prepared hollow spindle-like α-Fe₂O₃ exhibits a good response and reversibility to some organic gas, such as 2-propanol and acetone. Compared with other hematite nanostructures, the porous hollow hematite spindles show outstanding performance in gas sensing due to their large surface area and porous hollow structure. Because of the unique porous hollow structures of the samples, the photocatalytic property of the spindle-like α-Fe₂O₃ was also investigated.