Impurity‐Induced First‐Order Phase Transitions in Highly Crystalline V2O3 Nanocrystals

A first‐order phase transition in a bulk material is generally considered to arise at extended defects such as grain boundaries or dislocations, where the energetic barrier between the two phases is reduced. Downsizing a crystal to the nanoscale can exclude the number of defects, leading to enhanced kinetic stabilization of the metastable phase. Here, the disappearance of the first‐order metal–insulator transition in defect‐free V₂O₃ nanocrystals and the revival of the transition by introducing a certain Cr or Ti impurity content are investigated. The hysteresis width of the transition corresponding to the barrier height decreases with the impurity content. It is proposed that homogeneous impurity doping is a universal method that can control the occurrence of a first‐order phase transition in nanoscale materials.     

2,3-Dihydrohomofarnesal: Female Sex Attractant Pheromone Component of Callosobruchus rhodesianus (Pic)

Callosobruchus rhodesianus (Pic) (Coleoptera: Chrysomelidae: Bruchinae) is a pest of stored legumes through the Afro-tropical region. In laboratory bioassays, males of C. rhodesianus were attracted to volatiles collected from virgin females. Collections were purified by various chromatographic techniques, and the biologically active component isolated using gas chromatographic-electroantennographic detection analysis. Gas chromatography-mass spectrometry and NMR analyses suggested that the active compound was 2,3-dihydrohomofarnesal, i.e., 7-ethyl-3,11-dimethyl-6,10-dodecadienal. The structure was confirmed by non-stereoselective and enantioselective total synthesis. Using chiral gas chromatography, the absolute configuration of the natural compound was confirmed as (3S,6E)-7-ethyl-3,11-dimethyl-6,10-dodecadienal. Y-tube olfactomter assays showed that only the (S)-enantiomer attracted males of C. rhodesianus. The (R)-enantiomer and racemate did not attract males, suggesting that the (R)-enantiomer inhibits the activity of the natural compound. In combination with previous reports about sex attractant pheromones of congeners, we suggest that a saltational shift of the pheromone structure arose within the genus Callosobruchus.     

Polymer electrolyte membranes having sulfoalkyl grafts into ETFE film prepared by radiation‐induced copolymerization of methyl acrylate and methyl methacrylate

Polymer electrolyte membranes (PEMs) containing alkylsulfonic acid grafts can be prepared by radiation‐induced graft copolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) into a poly(ethylene‐co‐tetrafluoroethylene) film followed by sulfonation of the MA units in the copolymer grafts using an equimolar complex of chlorosulfonic acid and 1,4‐dioxane (ClSO₃H‐Complex). PEMs with MA/MMA copolymer grafts that are 33%–79% MA units were prepared by preirradiation with a dose of 20 kGy and grafting in bulk comonomers at 60°C. The grafted films are treated with ClSO3H‐Complex to obtain PEMs with ion exchange capacity of 0.36‐0.81 mmol/g (sulfonation degrees of 20%–40%) and proton conductivity of 0.04‐0.065 S/cm. These values can be controlled by changing the MA content the sulfonation occurring at an α‐carbonyl carbon. The PEMs with higher MMA content showed higher durability in water (80°C) and under oxidative conditions (3% H₂O₂) at 60°C. This is because the PMMA grafts in the PEMs have no proton at an α‐carbonyl carbon, which is considered to be a trigger of the degradation of grafting polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of fluorinated polymer electrolyte membranes by radiation grafting and atom transfer radical polymerization techniques

A novel polymer electrolyte membrane was synthesized by radiation-induced grafting and consequent atom transfer radical polymerization (ATRP). First, bromine-containing perfluorinated grafts were prepared by radiation grafting of 2-bromotetrafluoroethyl trifluorovinyl ether (BrTFF) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film. Then, the bromine atoms in the ETFE-g-PBrTFF grafted films were acted as initiators, and the films were treated with Cu(I)-based catalytic system of a CuBr and 2,2′-bipyridyl (bpy) for the ATRP. By adjusting the molar ratio of initiator/CuBr/bpy and the reaction temperature, branched poly(styrene) with a grafting yield of above 100% on the poly(BrTFF) main chains was constructed in ETFE-g-PBrTFF films. Thermal analysis revealed that the perfluorinated poly(BrTFF) main chains were miscible to ETFE, whereas the hydrocarbon poly(styrene) branches were phase-separated from the ETFE-g-PBrTFF film. Sulfonic groups could be further introduced into the poly(styrene) grafts of ETFE-g-PBrTFF-g-PS films with homogeneous distribution in a perpendicular direction to the membrane surface. The resulting membrane with a styrene grafting yield of 15% exhibited higher proton conductivity than commercial Nafion 117 membrane. Likewise, it had better chemical stability than ETFE-g-PSSA membrane prepared by conventional radiation-induced grafting.     

A human-machine cooperative system for generating sign language animation using thermal image

We propose a new approach aimed at sign language animation by skin region detection on an infrared image. To generate several kinds of animations expressing personality and/or emotion appropriately, conventional systems require many manual operations. However, a promising way to realize a lower workload is to manually refine an animation made automatically with a dynamic image of real motion. In the proposed method, a 3D CG model corresponding to a characteristic posture in sign language is made automatically by pattern recognition on a thermal image, and then a person’s hand in the CG model is set. The hand part is made manually beforehand. If necessary, the model can be replaced manually by a more appropriate model corresponding to training key frames and/or the model can be refined manually. In our experiments, a person experienced in using sign language recognized the Japanese sign language of 71 words expressed as animation with 88.3% accuracy, and three persons experienced in using sign language also recognized the sign language animation representing three emotions (neutral, happy and angry) with 88.9% accuracy. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Detection of martensite transformation in high temperature compressively deformed austenitic stainless steel by magnetic NDE technique

The present work demonstrates that a magnetic non-destructive evaluation technique can be useful for detecting the presence and extent of ferromagnetic martensitic phase in high temperature deformed 304 austenitic stainless steel.A good correlation between the martensitic transformation and magnetic parameters; saturation magnetization, coercive force and magnetic susceptibility have been obtained. Saturation magnetization was increased depending on the volume percentage of martensite transformation. The volume percentage of martensite was found to be dependent on the temperature and level of plastic strain. At temperatures below 623 K, martensitic transformation was detected after deformation of 10 to 40% plastic strain. A massive increase in martensite phase was observed in the specimen deformed at RT to 40% plastic strain.Compressive deformation at RT formed thermodynamically more stable long and broad shape of martensite. But as the temperature of deformation increases lath shape gradually converted into needle shape.Coercive force was exclusively connected with size, shape and spatial distribution of martensite. For specimens deformed at 523 K coercive force were much higher than those of the specimens deformed at RT. Coercive force decreased remarkably at temperatures above 623 K. Formation of ferromagnetic martensite in a paramagnetic matrix was also accompanied by an increase in magnetic susceptibility. Low magnetic susceptibility at temperatures above 623 K was due to disappearance of martensitic phase.     

A Constraint-Based Approach for Visualization and Animation

TRIP systems are tools for visualization and animation. They are based on a constraint-based model of bi-directional translation between abstract data and pictorial data. Using these systems, programmers can visualize abstract data, and animate various algorithms and processes, simply by providing a declarative mapping rule. This paper presents this model for visualization and animation, focusing on the use of constraints, and also presents the TRIP systems with examples of visualization and animation.     

Electroplating of zirconium and aluminum hydroxide thin films following anodic dissolution of corresponding metal anodes in organic medium

Zirconium (IV) hydroxide or hydrate oxide films, which are typically difficult to prepare by electrochemical methods using aqueous solutions, are easily fabricated in an acetone bath using Zr anodes as the metal sources and a metal-free solvent containing halide ions as the supporting electrolyte. This method is also confirmed to be applicable to aluminum anodes. In the early stage of electrolysis, anodic oxidation of the metal anode proceeds in the presence of water as an impurity in the solvent. Subsequently, pitting corrosion of the oxide film on the metal anode occurs as a result of the action of halide ions. The corrosiveness of the halogen additive appears to be an important factor determining the dissolution or deposition of metal species in this stage. That is, Br^– is more active for electrochemical dissolution of a passive oxide film on the anode compared to I^–. Finally, Zr species are deposited on the cathode surface via reactions with cathodically generated hydroxide ions. In these processes, the metal plate acts as a soluble anode and as a metal source for electrodeposition. The coating of Zr (IV) hydroxide film on a stainless steel substrate is shown to act as an effective barrier against electrolytic corrosion.     

Preparation of KTiOPO4 thin films on different substrates by pulsed laser deposition

Pulsed laser deposition (PLD) technique is applied in fabrication of thin films of KTiOPO₄ (KTP) material, which possesses electro-optic and nonlinear optical properties. Thin film fabrication of optically functional KTP on fused silica and different sapphire substrates by changing an ambient oxygen pressure and a substrate temperature during PLD is investigated. Highly oriented KTP thin films could be grown on sapphire $ {\left( {11\overline{2} 0} \right)} $ in an oxygen atmosphere by PLD using a composite target whose stoichiometry is nearly same as KTP. Although the film contained polycrystalline crystallites, predominant crystallites seemed to be epitaxially grown.