Akira Hatano

The diagonal bond method: A new lattice polymer model for simulation study of block copolymers

A new lattice model for Monte Carlo simulations of dense polymer melts, developed in the spirit of Verdier–Stockmayer algorithm on square and simple cubic lattices, is presented. By introducing diagonals of squares and cubes as bonds, the lattice model acquires a large number of configurations and wiggling local moves. While it maintains the excluded volume interactions of monomers, it allows bond crossings and phantom moves, which result in a high mobility of polymers. For an application, we carry out simulations of symmetric A–B block copolymer melts and observe a first‐order transition. We also show the stretching of the chains, namely, the non‐Gaussian character, as a function of temperature. A quicker evolution towards thermal equilibrium enables us to form an ordered tricontinuous double‐diamond (OTDD) phase for linear A–B–C triblock copolymers and a new cylindrical phase for star A–B–C triblock copolymers.

VUV Photoelectric Yield Spectra in Thin Films of KCl, KBr and RbCl at 80 K

Relative photoelectric yield spectra of thin films in KCl, KBr and RbCl are investigated in the photon energy 7 eV–40 eV range at 80 K as well as at room temperature. Several new characteristics of the spectra due to the thin film specimens and due to the lower temperature are observed. It is revealed that the yield spectra dominantly reflect the photo-absorptions modified by the inelastic electron-electron scattering in the valence excitation region and by the Auger process especially in the core excitation region. A large yield peak due to the next deeper core level K + 3 s or Rb + 4 s is newly identified in a photon energy range of 30–40 eV. Interband thresholds of the yield spectra are observed and the electron affinities are derived.

Vacuum UV Photoelectric Yield Spectra of BaF 2 and SrF 2 Crystals

Total photoelectric yield spectra of BaF 2 and SrF 2 thin film crystals are relatively measured in the photon energy range of 10–35 eV with high resolution at room temperature. The yield spectra obtained are investigated in comparison with available reflection spectra in both materials and with an excitation spectrum of Auger free luminescence in BaF 2 . Evidence for a violation of Auger free process is observed in BaF 2 . It is also revealed that the total width of the Ba 2+ 5p core level is extraordinarily wide, 6 eV.

Distribution of the Substituents in Heterogeneously Methylated Celluloses

Four methyl celluloses made from cotton linters with dimethyl sulfate and alkali in toluene and one commercial product were hydrolyzed. Unsubstituted, monomethyl, di methyl, and trimethyl glucose in the hydrolyzates were separated by filter paper chro matopile, and the results were compared with the calculated values of Spurlin and the experimental values of other investigators.

Effective thickness of adsorbed polymer in a shear field

Abstract The effective thickness of the adsorbed polymer layer in a linear shear field was investigated theoretically. It is found that, when the shear strength is weaker than a certain critical value, distribution of segments perpendicular to the field is unaltered from that at equilibrium, but when the shear strength goes over the critical value, the distribution changes abruptly according to the nature of the adsorption.

Absorption spectra of quantum well excitons in alkali halide multilayer structures

Optical absorption spectra of quantum well excitons in KCl-KBr and RbCl-KBr alternating multilayer structures are studied. The absorption bands of excitons confined in the well exhibit blue shifts and steeper rise as compared with the bulk exciton band. These spectral characters are explained in terms of the quantum confinements. A sinusoidal potential profile of the multilayer is proposed to explain the interface-mixture effect and is confirmed by the observed spectra. A simple model of the sinusoidal well is also proposed.

VACUUM UV PHOTOELECTRON DYNAMICS IN ALKALI EARTH FLUORIDES : YIELD, AUGER EFFECT, AND LUMINESCENCE

Abstract Photoelectric yield spectra and photoluminescence of alkali earth fluorides; CaF 2 , SrF 2 and BaF 2 , are studied in VUV region at room temperature and several low temperatures. The contribution of core hole and core exciton to the Yield are explained in terms of several Auger processes. A complementary character between the yield and the uminescence is revealed.

Erratum for 'Absorption spectra of quantum well excitons in alkali halide multilayer structures'

Corrections to Physica Scripta 41 95 (1990) Unfortunately there were some errors in the printing process. In the references at the page 98, 1. The line of reference number 6 should be deleted. 2. All numbers more than 7 should be subtracted unity and become a series from 6 to 20.

ON CUPRIETHYLENE DIAMINE AS A SOLVENT FOR THE PRECISE DETERMINATION OF PULP VISCOSITY.

Cuprammonium hydroxide has long been used as a dispersing agent for the determination of pulp viscosity. Cupriethylene diamine dispersions are, however, much less sensitive to low oxygen concentration than are cuprammonium hydroxide dispersions. This solution is an excellent dispersion medium for cellulose, it is nonvolatile, , it has excellent keeping qualities, provided it is kept stored under an atmosphere of nitrogen, and it is easily prepared in quantity.A cupriethylene diamine trial method for rapid viscosity determination was presented and it was recognized that the relative viscosity of various pulp can be determined to an accuracy of approximately±5% by this method.