Simulation of cyclic dynamics in isothermal gas-solid reaction systems effects of the frequency of sinusoidal perturbation in the bulk gas concentration

The dynamic responses of a gas-solid reaction system to a sinusoidal perturbation in the bulk gas concentration are analyzed. Effects of the frequency variations on the gas and solid concentration profiles and the solid conversion are comprehensively examined based on the volume reaction model under the isothermal condition. The results show that the solid conversion can be accelerated as much as 50% and retarded as much as 50% depending on the frequency and the amplitude of the perturbation. The relationships between the reactant concentrations at the surface and the center are elucidated by means of phase-plane plots.     

Experiments on fracture behavior of single fiber-brittle zone model composites

Single fiber-brittle zone model composites were prepared by the electroless plating method, in order to know the effect of the interfacial bonding strength between the fiber and brittle zone on the fracture strength of the composites. For the case of weak inter-facial bonding, the notch formed by the fracture of the brittle zone at an early stage of deformation was unable to extend into the fiber due to a premature interfacial debonding. Therefore no deleterious effect of the brittle zone on the fiber strength was found. For the case of strong interfacial bonding, the formed notch extended into the fiber, resulting in loss of the fiber strength. The strength of such a composite was well explained by the theory recently proposed by Ochiai and Murakami. The important parameters to describe the fracture behavior of the fiber coated with the brittle zone, the strain energy release rate of the fiber and the permissible thickness of the brittle zone, below which the strength of the fiber is not reduced, were experimentally determined.     

Tritium release from bulk of carbon-based tiles used in JT-60U

Tritium thermal release behavior from the isotropic graphite tile and the CFC tile used as the plasma facing material of JT-60U was experimentally examined. Whole tritium retained in the bulk of tile could not be released by dry gas purge at high temperature in such a period as one day. Utilization of the isotope exchange reaction using purge gas with hydrogen or humid gas was more effective to release the retained tritium. However, approximately 1% of retained tritium was not recovered by the isotope exchange reaction with dry hydrogen even though such high temperature as 1200 °C was applied. Combustion method with oxygen was required to recover all tritium left in the deeper site of the tile. It was observed that combustion of isotropic graphite tile and CFC tile became vigorous at higher temperature than 700 °C though the combustion rate was rather slow at 650 °C.     

NEW APPLICATIONS OF CHEMILUMINESCENCE FOR SELECTIVE GAS ANALYSIS

Chemiluminescence (CL) is a powerful analytical tool for trace gas measurements. In this mini-review, we present reactions and spectra of ozone-induced CL for various compounds and techniques for detecting such CL. Next discussed are CL applications where real gas samples were successfully measured. Chemiluminescence monitoring has been used as universal nitrogen and sulfur detectors for gas chromatography and capillary electrophoresis. Chemiluminescence detection can be used as the basis of compact, affordable, and sensitive analyzers for real-sample analysis. Isoprene and sulfur compounds in breath and atmospheric samples have been successfully measured by coupling with a small collection system. Short-term (5 min) sorbent collection enhances the CL signal and considerably reduces interference. For sulfur gas analysis, methyl mercaptan and dimethyl sulfide can be separated on the same column that is used for collection. Waterborne arsenic is measured by automated arsine generation and CL reaction of arsine and ozone. In addition to gas-phase CL, more recent efforts towards the determination of gases by CL generated at solid/gas and liquid/gas interfaces are also discussed.     

Submolecular resolution viscoelastic imaging of a poly(p-toluene-sulfonate) single crystal using force modulation microscopy

Submolecular resolution viscoelastic imaging of a poly(2,4-hexadiyne-1,6-diyl bis(p-toluene-sulfonate)) single crystal was achieved using force modulation microscopy under ambient conditions. The elastic image clearly visualized the structure of p-toluene-sulfonate side chains. The viscotic image visualized that the phase delay on the main chains was smallest, while it became largest on the toluene rings in the side chains. The result is considered to be closely related to the molecular dynamics of the crystal.     

Design of a dual‐input SC DC–DC converter realizing negative outputs

Aimed at a back‐lighting application, a dual‐input switched‐capacitor (SC) DC–DC converter with battery charge process is proposed in this paper. The proposed converter can realize −1/N× (N = 2,3,…) step‐down conversion as well as (N + 1)/N× step‐up conversion. By converting clean energy such as solar energy, the proposed dual‐input converter not only drives light‐emitting diodes (LEDs) but also recharges the battery, although conventional single‐input converter only consumes battery energy. In the proposed converter, the −1/N× stepped‐down voltage is generated to drive the LED's cathode when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike conventional converters, the battery is charged by the (N + 1)/N× stepped‐up voltage when the LED back light is in standby mode. Hence, the proposed converter can realize long battery run time. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments. The derived theoretical formulas will be helpful to estimate circuit characteristics, because the theoretical results correspond well with the simulation program with integrated circuit emphasis (SPICE) simulation results. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

In situ AFM study of near‐surface crystallization in PET and PEN

The surface crystallization behavior of poly(ethylene terephthalate) (PET) and poly(ethylene 2,6‐naphthalate) (PEN) spin‐coated thin films was compared by means of atomic force microscopy (AFM) with an in situ heating stage. As the films were heated up stepwise, characteristic surface crystals appeared at a crystallization temperature (T_c) in the near‐surface region which is about 15 °C under the bulk T_c, and were replaced by bulk crystals when the temperature was increased to the bulk T_c. In the case of films whose thickness is less than 70 nm (PET) and 60 nm (PEN), significant increases in the bulk T_c were observed. Scanning force microscopy (SFM) force‐distance curve measurements showed that the glass transition temperature (T_g) of the near‐surface region of PET and PEN were 22.0 and 26.6 °C below their bulk T_g (obtained by DSC). After the onset of surface crystallization, edge‐on and flat‐on crystals appeared at the free surface of PET and PEN thin films, whose morphologies are very different to those of the bulk crystals. Although the same general behavior was observed for both polyesters, there are significant differences both the influence of the surface and substrate on the transition temperatures, and in morphology of the surface crystals. These phenomena are discussed in terms of the differences in the mobility of polymer chains near the surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44269.     

Conformal Geometry of Statistical Manifold with Application to Sequential Estimation

Abstract

We present a geometrical method for analyzing sequential estimating procedures. It is based on the design principle of the second-order efficient sequential estimation provided in Okamoto et al. (1991 Okamoto , I. , Amari , S. , and Takeuchi , K. ( 1991 ). Asymptotic Theory of Sequential Estimation: Differential Geometrical Approach , Annals of Statistics 19 : 961 – 981 .[Crossref], [Web of Science ®] , [Google Scholar]). By introducing a dual conformal curvature quantity, we clarify the conditions for the covariance minimization of sequential estimators. These conditions are further elaborated for the multidimensional curved exponential family. The theoretical results are then numerically examined by using typical statistical models, von Mises-Fisher, and hyperboloid models.