Swelling of nylon 6 film due to water sorption

Dimensional changes in nylon 6 film on absorption and desorption of water were studied as functions of time and the amount of absorbed water. For absorption, a plot of film expansion versus the square root of time was sigmoidal in the initial region and did not coincide with the sorption curve: the latter was linear in the same region. This behavior is very similar to that reported for nylon 6 fiber by Kunzman. A theoretical analysis based on certain assumptions about the molecular state of nylon 6 gave good agreement with experimental results. By this analysis it was shown that the characteristic swelling behavior arises from instantaneous relaxation of the polymer molecules and is not connected with a time lag between water absorption and expansion of the polymer, as Kunzman proposed.     

Atomic emission spectrometry of metal oxides using shock tube excitation

The behavior of powdered samples in the region behind the incident and reflected shock wave were investigated. When the particle size is less than 8 μm, the powdered samples are effectively vaporized and excited to emit spectral lines. It was shown that the sample particles are scattered behind the incident wave and concentrated again in a narrow portion near the observation window by the use of a reflector so that intense emission can be attained. As an excitation source, the shock tube was used for the determination of trace metals contained in copper oxide.     

General description of mechanical anisotropy of semicrystalline polymers in relation to orientation of structural units composed of crystalline and noncrystalline materials

A mathematical representation of the transformation of an orientation function between two sets of Cartesian coordinates is discussed in terms of a series expansion of the distribution function in generalized spherical harmonics. A general procedure for calculating the mechanical anisotropy of a single-phase system (a polycrystalline material) from the orientation of its structural units and the intrinsic mechanical anisotropy of the structural unit is discussed in relation to the transformation of the orientation distribution function, i.e., mutual conversion of the coefficients in the expansion of the distribution function between the two sets of Cartesian coordinates. The procedure is extended to a two-phase systems (semicrystalline polymers) containing structural units composed of crystalline and noncrystalline materials in three different geometrical arrangements.     

Necessary conditions for the convergence of kullback-leibler’s mean information

Summary Two types of necessary conditions are given for the convergence of Kullback-Leibler’s mean information, one of which is connected with an asymptotic equivalence of two sequences of probability measures, and in special cases, with convergence of a sequence of probability distributions. The other is given in terms of the generalized probability density functions.     

Asymptotic equivalence of probability distributions with applications to some problems of asymptotic independence

Summary The problem of asymptotic approximation is formulated in a generalized form, and the basic concepts of asymptotic equivalence of probability distributions, which are fundamental to the study of asymptotic approximation problems, are established precisely. For the purpose of practical applications, some useful criterions for the asymptotic equivalence are given.     

Nuclear moments as a probe of electronic structure in material, exotic nuclear structure and fundamental symmetry

We report our studies in various fields of Physics through nuclear moments utilizing the β-NMR technique, including material sciences, nuclear structures and fundamental symmetries. Especially, we focus on the recent progress in the studies on the electronic structure in Pt through Knight shifts of various impurities, lattice locations of impurities, electric field gradients, the analysis of nuclear spin in terms of its components, anomaly in the spin expectation value for ⁹C-⁹Li mirror pair, the G-parity conservation law, and the Ramsey resonance on UCN for future neutron EDM measurements.     

Preparation and photosensitizing property of novel Cd10S16 molecular cluster dendrimer

A new Cd10S16 molecular cluster dendrimer has been prepared and characterized; photooxygenation reaction using the molecular cluster dendrimer as a photosensitizer was successful.