Structural and morphological changes of monolayers of a block copolymer with dendron and perfluoroalkyl side chains by mixing a perfluorooctadecanoic acid

Hybrid Langmuir and Langmuir-Blodgett monolayers of a perfluorooctadecanoic acid mixed with a rigid block copolymer, poly(3,5-bis(3,5-bis(benzyloxy)benzyloxy)benzyl methacrylate-randommethacrylic acid)-block-poly(2-perfluorooctylethyl acrylate), which is composed of benzyloxy dendron side chains and perfluorinated side chains, were prepared and characterized by surface pressure-surface area isotherms, atomic force microscopic images and neutron and X-ray reflectometries. The two-dimensionally phase-separated structures of monolayer films and their morphologies with plateau and terrace were confirmed. The monolayers were separated into a dendron layer, a perfluorinated layer, and a carboxyl layer. The layer formation is originated not only in the intermolecular interaction between a perfluorooctadecanoic acid and a block copolymer but also in the geometry of the molecules. Especially, the amphiphilicity of perfluorinated surfactant plays a role to the ordered array of the block copolymers.     

The sensory region of muscle spindles in the posterior cricoarytenoid muscle of the marmoset

We examined muscle spindles in the posterior cricoarytenoid (PCA) muscle of the marmoset. The spindle capsule contained only one intrafusal muscle fiber which did not form a typical aggregation of equatorial nuclei such as bags and chains. The intrafusal fiber was innervated by sensory endings which branched and arranged irregularly. These sensory endings lay on the surface of the fiber in shallow grooves or deeply penetrated into it. These findings suggest that the muscle spindles in the marmoset PCA muscle are strikingly different in the structure of intrafusal fibers in the arrangement of sensory endings from those in common mammalian skeletal muscles.     

Finite-difference time-domain analysis of time-resolved reflectance from an adult head model composed of multilayered slabs with a nonscattering layer

Finite-difference time-domain (FDTD) analysis has been used to predict the time-resolved reflectance from multilayered slabs with a nonscattering layer. Light propagation across the nonscattering layer was calculated based on the light intensity characteristics along a ray in free space. Additional equivalent source functions due to light from scattering regions across the nonscattering region were introduced into the diffusion equation and an additional set of the diffusion equation was solved by FDTD analysis by employing new boundary conditions. The formulation was used to calculate time-resolved reflectances of three- and four-layered slabs containing a nonscattering layer. The received light intensity and the mean time of flight estimated from the time-resolved reflectance are in reasonable agreement with previously reported experimental data and Monte Carlo simulations.     

Photo-induced properties of anodic oxide films on Ti6Al4V

Photocatalytic activity and wettability of the anodic oxide layer on Ti6Al4V prepared by anodization in a sulfuric acid electrolyte are explored. The oxide is composed mainly of TiO₂ with V₂O₅, VO₂ and Al₂O₃. The crystal structure of the TiO₂ varies from anatase to rutile with the sulfuric acid concentration in the electrolyte. Anatase exhibits better photocatalytic activity compared with rutile, which is different from those on Ti and Ti-Nb-Sn alloy. Contact angles of the oxides decrease with ultraviolet light illumination, and hydrophilicity is observed in the rutile oxide. Both photocatalytic activity and hydrophilicity are inferior to the corresponding Ti and Ti-Nb-Sn alloy, which is explained by the presence of Al₂O₃ in the anodic oxide.     

Structure of optical singularities in coaxial superpositions of Laguerre-Gaussian modes

We investigate optical singularities in coaxial superpositions of two Laguerre-Gaussian (LG) modes with a common beam waist from the viewpoints of a general formulation of phase structure, experimental generation of various superposition beams, and evaluation of the generated beams' fidelity. By applying a holographic phase-amplitude modulation scheme using a phase-modulation-type spatial light modulator, output fidelity beyond 0.960 was observed under several typical conditions. Additionally, an elliptic-type folded singularity, which provides a different class of phase structures from familiar helical singularities, was predicted and observed in a superposition involving two LG modes of both radially and azimuthally higher orders.     

Comparative risk study of hydrogen and gasoline dispensers for vehicles

This paper describes an investigation into the acceptability of installing hydrogen dispensers in public areas based on risk assessments. Because gasoline dispenser risks have been widely accepted for many years, they were used as a benchmark in this study to analyze the risks of hydrogen dispensers. More specifically, we performed risk assessments for both hydrogen and gasoline dispensers and then compared and analyzed the results. We began the process by creating models for both hydrogen and gasoline dispensers that represented their various specifications and elements. Next, potential accident scenarios for each dispenser model were identified by failure mode effect analysis (FMEA) and hazard and operability study (HAZOP). The risks of each scenario were then qualitatively evaluated and the results were organized into risk matrices. By comparing the results of both hydrogen and gasoline dispensers with and without existing safety measures, the appropriateness of their safety measures were validated. Furthermore, by comparing the results of hydrogen and gasoline dispenser safety measures, it was confirmed that the risk levels of the two types were practically equivalent. Therefore, we concluded that the risks involved with installing hydrogen dispensers in public areas can be considered acceptable.     

Quantitative evaluation of die casting surface defect severity by analyzing surface height

It is necessary in factories to assess the severity of the surface defects of castings, as a slight surface defect will be taken as qualified when it brings no bad effect or it can be removed by the subsequent processing. In practical production, professional technicians visually inspect the surface defect severity according to their individual experience. Therefore, it is difficult for them to maintain the same standard and accuracy in the subjective, tedious and labor-intensive work. Recently, image processing techniques based on optical images have been applied to achieve better accuracy and high efficiency. Unfortunately, optical images cannot directly quantify surface depth, which works as a crucial factor in the practical assessment of surface defect severity. The surface roughness evaluation algorithm, which takes into account of both area and depth information of the assessed surface, was applied to directly characterize surface defect severity based on surface asperity rather than optical image. The results using standard casting pieces show that surface defect severity has no apparent dependence on surface roughness. However, the subsequent results show that the root-mean-squared-deviation (RMSD) of surface gradient of flow line defects positively correlates with the increase of defect severity. The other types of defect do not present such tendency. Thus, practical workpieces with flow line defects on the surface were used to verify the universality of this tendency. The results show that surface roughness of an unqualified workpiece is larger than that of a qualified workpiece after surface slope adjustment, but presents no obvious coincidence before the adjustment. In contrast, the RMSD of an unqualified workpiece, no matter before or after the adjustment, is larger than that of a qualified one.     

Characteristics of transient vortices in the boundary layer on a rotating disk under orbital motion

The objective of this study is to experimentally examine the characteristics of transient vortices in the boundary layer on a disk undergoing both rotation and orbital motion. The velocity fluctuations on a rotating, orbiting disk （disk radius equal to orbital radius） are measured by the hot-wire method, and the effects of orbital motion on the transient vortices in the boundary layer are examined. When the ratio of the orbital speed to the speed of rotation is i-0.025, the interval of transient vortices depends on only the orbital radius, regardless of the directions of rota- tion and orbital motion. The rate of low-frequency disturbances increases as the orbital speed increases, and the vortices induced by these low-frequency disturbances travel over the disk and then develop in the region of in- creased velocity. Consequently, no vortices generated on a rotating disk under orbital motion are stationary rela- tive to the disk.     

An Improvement of the Portmanteau Statistic

Abstract. The portmanteau statistic is based on the first m‐residual autocorrelations, and is used for diagnostic checks on the adequacy of fit of a model. In this article, we propose a modified portmanteau statistic with a correction term that allows for the use of small values of m for the chi‐squared test. For this modification, we take a different approach to that suggested by Ljung [Biometrika (1986), Vol. 73, pp. 725–30]. Their empirical behaviour is clarified using asymptotic theory.     

Preparation of Aluminum Oxynitride by Nitridation of a Precursor Derived from Aluminum–Glycine Gel and the Effects of the Presence of Europium

Spinel-type AlON, Al_2.75□_0.25O_3.74N_0.26, was obtained by ammonia nitridation of an oxide precursor prepared by peptizing a glycine gel with aluminum nitrate. To achieve crystallization, the nitrided product had to be annealed at 1500°C for 10 min in flowing nitrogen. The use of glycine instead of citric acid was important for obtaining a white product without residual carbon. A similar preparation method was used for adding small amounts of europium below 10 mol%. A strong blue emission was observed for products ranging from 0.5 to 3.0 mol% Eu doping. The product with 0.5 mol% doping had a maximum emission intensity at 400 nm for an excitation of 254 nm. The products with 1 and 3 mol% doping showed double maxima at 475 and 520 nm. These three emissions were due to the presence of divalent europium in the EuAl₁₂O₁₉ magnetoplumbite-like aluminum oxynitride impurity mixed with the AlON spinel major phase. The 1 mol% Eu-doped product exhibited expanded hexagonal lattice parameters ( a =0.5591 and c =2.236 nm) compared with the values for EuAl₁₂O₁₉ magnetoplumbite itself, observed in the 7.7 mol%-doped product without any strong emission. The above spectrum change was discussed in relation to the coordination around Eu²⁺.