Preparation of hybrid films of aluminosilicate nanofiber and conjugated polymer

We have demonstrated the preparation of hybrid films of aluminosilicate nanofiber (imogolite) and water-soluble poly(p-phenylene) (WS-PPP), which has sulfonate groups. The imogolite/WS-PPP hybrid gel could be prepared by mixing a solution of these two materials and subsequent centrifugation. The aluminol (AlOH) groups on the surface of imogolite would be protonated under acidic conditions to afford AlOH₂⁺ groups that can interact with sulfonate groups (SO₃^?) of WS-PPP. Based on this ionic interaction, a layer-by-layer (LBL) assembly was applied to fabricate the hybrid films of imogolite nanofibers and WS-PPP. The deposited amounts of WS-PPP and imogolite were measured by quartz crystal microbalance (QCM) measurements and scanning electron microscopy (SEM) observation. Atomic force microscopy (AFM) observation revealed that imogolite nanofibers were well networked in the LBL hybrid film.     

Mixture law including particle-size effect on fracture toughness of nano- and micro-spherical particle-filled composites

The effects of particle diameter and volume fraction on fracture toughness of nano- and micro-spherical particle-filled composites were investigated. The purpose was to create a mixture law of fracture toughness based on experimental results of spherical silica particle–filled epoxy composites and a theoretical approach. The fracture toughness of composites was found to be tailored independently by exchanging different particle sizes, and elastic and viscoelastic properties were found to be governed by the volume fraction of the particles. In a theoretical analysis, a mixture law of fracture toughness, composed of the elastic moduli, diameter, and volume fraction of particles and the elastic moduli of matrix resins was proposed. Its validity was demonstrated in a comparison with the experimental results.     

Polishing of single point diamond tool based on thermo-chemical reaction with copper

This paper describes a new polishing method for diamond cutting tools. The method is based on the principle of oxidization of copper and deoxidization of copper oxide by carbon. A diamond tool was brought into contact with a copper plate, heated in air to a range of 323–523 K. The depth of the removed layer of diamond increased almost linearly with contact time and reached approximately 7 nm after 6 h. In this erosion process, pre-existing microcracks on the diamond surface were reduced. In comparison with the mechanically polished tool, the thermo-chemically polished tool was highly resistant to chipping and yielded a significant rise in tool life.     

Flame-Sprayed Y<Subscript>2</Subscript>O<Subscript>3</Subscript> Films with Metal-EDTA Complex Using Various Cooling Agents

In this study, yttrium oxide (Y₂O₃) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H₂-O₂ combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y₂O₃ films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y₂O₃ films showed only a few cracks and minor peeling in their microstructures. For instance, the Y₂O₃ film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film’s temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit’s temperatures.     

Production of (S)-2-chloropropionate by asymmetric reduction of 2-chloroacrylate with 2-haloacrylate reductase coupled with glucose dehydrogenase

(S)-2-Chloropropionate is a synthetic intermediate for phenoxypropionic acid herbicides. We constructed a system for asymmetric reduction of 2-chloroacrylate to produce (S)-2-chloropropionate with recombinant Escherichia coli cells producing 2-haloacrylate reductase from Burkholderia sp. WS and an NADPH regeneration system. The system provided 37.4 g/l (S)-2-chloropropionate in more than 99.9%e.e.     

Crystal and electronic band structures of homologous compounds ZnkIn2Ok+3 by Rietveld analysis and first-principle calculation

Crystal structure of homologous compounds, Zn₃In₂O_6, Zn₄In₂O₇, Zn₅In₂O₈, Zn₇In₂O₁₀, and In₂O₃ were refined by X-ray Rietveld analysis. Band structures of the homologous compounds were evaluated by first-principle calculation (Cambridge Serial Total Energy Package, CASTEP), using the structural data obtained from the Rietveld analysis. According to the results of CASTEP calculations, a sharp cut-off at the Fermi level could be observed when In³⁺ preferentially occupies the tetrahedral site (Zn₃In₂O₆(4)) or the trigonal bipyramid site (Zn₃In₂O₆(5)) in the (InZn_k)O_k+1⁺ layers. The cut-off at the Fermi level could not be observed when In³⁺ and Zn²⁺ are totally disordered at these sites. Electronic structure calculation suggested that Zn₃In₂O₆(4) is a good conductor and that Zn₃In₂O₆(5) is a poor conductor. Results of geometry optimization indicate that the formation enthalpy of Zn₃In₂O₆(4) was lower than that of Zn₃In₂O₆(5). Considering the electronic structure and the formation enthalpy, Zn₃In₂O₆(4) in which In³⁺ in the (InZn_k)O_k+1⁺ layer occupies the tetrahedral site preferentially, is likely to be the favored structure.     

Characterization and biological application of YAG:Ce3+ nanophosphor modified with mercaptopropyl trimethoxy silane

We focus on the inorganic nanophosphor of YAG:Ce³⁺ nanoparticles as an alternative fluorescent probe instead of organic dyes for biological application. YAG:Ce³⁺ nanoparticles have the green emission at 530 nm under the excitation of blue light at 450 nm. Conventional biochemical equipments for organic dyes can be used for YAG:Ce³⁺ nanoparticles. SH groups were introduced by surface modification of YAG:Ce³⁺ nanoparticles with 3-mercaptopropyl trimethoxy silane, and were characterized by X-ray fluorescence analysis, FT-IR, and Ellman method. We demonstrated tagging avidin-immobilized agarose gel beads with biotinylated-YAG:Ce³⁺ nanoparticles, and tagging rabbit IgG-immobilized agarose gel beads with antirabbit IgG-immobilized YAG:Ce³⁺ nanoparticles.     

A spherical code and stress tensor inversion

A spherical code is a set of many points arranged at more or less uniform intervals on a hypersphere. Here, we present a spherical code comprising 60,000 points in five-dimensional space and the list of the uniformly distributed reduced stress tensors corresponding to the points. This code benefits tectonic studies. By the way of example, it is demonstrated how the code improves the resolution of stress tensor inversion.     

Regulated plus and minus power supply using approximately 2DOF robust digital control

A plus and minus switching power supply is needed for many applications, for example an audio power supply. Since the changes in the output voltage of such loaded power amplifiers are large, the voltage of the power supply is also subject to large changes. In order to suppress these changes, a capacitor with a large capacity is usually used at the output end. If the capacities are reduced, the power supplies can be compacted. In this article, we show that the capacities can be reduced by using robust digital control using approximately 2DOF. The resulting controller is actually implemented on a digital signal processor (DSP). We show from experiments that the power supplies can be compacted by a robust controller.