Effects of strain path shapes on non-proportional cyclic plasticity

The title problem was discussed to facilitate the formulation of constitutive models of cyclic plasticity under general states of loading. A series of plastic strain controlled cyclic tests was performed by applying combined axial force and torque to thin-walled tubular specimens of Type 316 stainless steel at room temperature. These tests consist of cyclic loading along uniaxial, torsional, cruciform, stellate in eight directions, square and circular plastic strain paths with a constant amplitude of equivalent plastic strain.The results of these tests showed that the strain-hardening depends markedly on the shape of the plastic strain path, and that the strain-hardening (measured by equivalent stress amplitudes) in the saturated state is significant in the order of circular, square, stellate, cruciform and proportional paths. It was also observed that these saturated values were independent of the less significant plastic strain cycles experienced in the past. Finally, the characteristic features of strain-hardening mechanisms under non-proportional loadings were discussed in some detail on the basis of the present results.     

Pico-second spectroscopy of the secondary radiation from resonantly excited excitonic molecules in CuCl

Pico-second time-resolved measurements of the two-photon resonant Raman scattering via excitonic molecules in CuCl were carried out for the first time. The Raman scattering leaving transverse excitons decays as fast as the laser light. When the energy of the incident light falls in the vicinity of the two-photon resonant absorption, both Raman and luminescence lines are simultaneously observed. In case of just resonant excitation, the transient response indicates that the secondary radiation can be decomposed into the Raman and the luminescence components as regards its temporal and spectral behavior.     

Measurement of the spectral distribution of a multi-mode dye laser light by using speckle patterns

A simple method of measuring the wavelength γ₁ and the spectral line spacing Δγ of a multi-mode dye laser light by using the correlated speckle patterns produced at the far-field of a diffuser is proposed. Examples of the obtained values of γ₁ and Δγ are 6.0 × 10³ Å and 3.0 × 10¹ Å, respectively.     

The electronic structures of cis-polyacetylene

The electronic structures of two possible forms of the so-called $\text{cis}$-skeletal polyacetylene ($\text{cis}$-polyacetylene) are investigated on the basis of the tight-binding LCAO-SCF-MO method under the CNDO/2 version. The analyses of the total energies per unit cell, the π bond orders and the interatomic interaction energies as to the both forms predict the $\text{cis}$-transoid backbone for the $\text{cis}$-polyacetylene. The examination of the patterns of particular molecular orbitals of the hypothetical $\text{cis}$-polymer with equal C-C bond lengths also supports the $\text{cis}$-transoid form.     

Determination of the change of nuclear charge radius of the119Sn Mössbauer transition by internal conversion

Radioactive¹¹⁹Sb was implanted into six host matrices (CaSnO₃, Pt, Y, Au,-Sn, Pb) and internal conversion electrons of the 23.87 keV transition in¹¹⁹Sn were measured with an iron-free magnetic spectrometer as well as Mössbauer spectra. In the analysis of the conversion spectra of outermost electrons, the overlapping K-LM Auger lines were subtracted using the Auger spectrum of tin measured with another source of^117mSn, and the shake-off effect accompanying the conversion process was considered. From the correlation between the Mössbauer isomer shifts and the intensity ratios of O-shell to N₁-shell conversion electrons, the change of the nuclear charge radius of the 23.87 keV transition of¹¹⁹Sn was deduced to be R/R=(0.87 ± 0.25) × 10^–4 for a uniform charge distribution ofR= 1.2 ×A ^1/3 fm or, equivalently, r²>—=(3.6 ± 1.0) ×10^–3 fm².     

Determination of electron effective mass from optical transition energy in InGaAs/InAlAs quantum wells

Nonparabolic effective mass of conduction subbands in InGaAs/InAlAs quantum wells (QWs), lattice-matched to InP, was quantitatively obtained by analyzing interband-optical transition spectra. Thickness of InGaAs well was 5.3, 9.4, and . Thickness of InAlAs barrier was about , and each QW was independent. Excellent agreement was obtained between experimental mass and theoretical mass predicted by Kane's three-level band theory on bulk InGaAs, in a wide energy range of from the bandedge. Method of experimental analysis on a relation between eigen energy and effective mass was described.     

Color removal method considering perceived lightness

Optical Review - A novel color removal method for digital color images is proposed. In this method, differences of colors in an input color image are reflected effectively, and the perceived...