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[en] A model to describe the change in the inelastic and fracture properties of reactor pressure vessel steels due to neutron irradiation in the ductile region (i.e., irradiation embrittlement) is developed. First, constitutive equations for unirradiated elastic-viscoplastic-damaged materials are developed within the framework of the irreversible thermodynamics theory. To take into account the effect of hydrostatic pressure on the nucleation and growth of microvoids, properly defined dissipation potential is used. Then, the effect of irradiation on the material behavior is incorporated into the proposed model as a function of neutron fluence Φ by taking into account the interaction between irradiation-induced defects and movable dislocations. As regards the damage strain threshold p_D, the mechanism of void nucleation due to pile-up of dislocations at the inclusions in the material is proposed first under unirradiated condition, and then the effect of irradiation on the mechanism is formulated. In order to demonstrate the validity of this model, it is applied to the case of uniaxial tensile loading of a low alloy steel A533B cl. 1 for the pressure vessel use of light-water reactors at 260 C. The resulting model can describe the increase in yield stress and ultimate tensile strength, the decrease in total elongation and strain hardening, and the strain rate dependence of yield stress due to neutron irradiation

[en] Complexation properties of a poly(dithiocarbamate) resin for Fe(III), Fe(II), Cr(VI), Cr(III), V(V), V(IV), T(IV), Mo(VI), W(VI), Th(IV), 14 rare earth elements, and Os are examined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Fe(III) and Cr(VI) complex with the resin, whereas Fe(II) and Cr(III) do not. Considerable differences in uptake also exist between V(V) and V(IV) and Ce(III) and Ce(IV). The digestion of the resin with nitric acid followed by dilution with (3 + 1) nitric acid-water is suitable for inductively coupled plasma-atomic emission spectrometry except for W

[en] Magnitude of scalar interaction is evaluated in an exact closed cosmological model of the Brans-Dicke theory. The ratio between the scalar interaction and the gravitation is 1/(3+2ß) and it is never negligible. Einstein's conjecture on Machian effect concerned with mass increase is also discussed briefly. (author)

[en] Properties of a closed cosmological solution with the negative coupling parameter of the scalar field compatible with Mach's principle in the Brans-Dicke theory are summarized

[en] The perturbation by a spherical rotating shell is investigated in a closed homogeneous and isotropic cosmological model of the Brans-Dicke theory to first order in an angular velocity of the shell. This model has a negative coupling parameter of the scalar field and satisfies the relation G (t) M/c²a (t) = π. The inertial frame at the origin is dragged completely with the same angular velocity when the rotating shell covers the whole universe. By a similar perturbation method, the distance dependence of the contribution from matter to the scalar field at the origin is obtained in this model. The contribution from nearby matter is negative because of the negative coupling constant, but the contribution from the whole universe is positive. The gravitational ''constant'' is almost determined by matter in the distant region

[en] Superconducting material parameters of the Nb film coatings on the quarter-wave resonator for the HIE-ISOLDE project were studied by fitting experimental results with the Bardeen–Cooper–Schrieffer Mattis–Bardeen (BCS-MB) theory. We pointed out a strong correlation among fitted estimators of material parameters in the BCS-MB theory, and used a procedure to reduce the uncertainty by merging two χ ² distributions of the surface resistance and effective penetration depth. In this procedure, unlike previous studies, BCS coherence length (ξ ₀) and London penetration depth (λ _L) were not fixed at their literature values in the calculation because in our film, whose thickness is from 2 to 13 μm, they may take altered values as a consequence of microstructual defects. Since surface resistance and penetration depth have similar dependencies on coherence length and mean free path, the effects of the correlation between the estimators of these two parameters could not be mitigated by just combining surface resistance and penetration depth data. We used upper critical field measurement by SQUID magnetometry to provide a complementary constraint to these RF measurements, and this allowed all the material parameters to be obtained by fitting the experimental data. In the best performing cavity, the determined parameters are ξ ₀ = 29 nm, λ _L = 26 nm, mean free path l = 99 nm, and coupling strength Δ₀/k _B T _c = 1.7. The coherence length is slightly shorter than for clean bulk Nb (39 nm) in the literature although the Nb film is thick and rather bulk-like. A poorly performing cavity showed weaker coupling constant Δ₀/k _B T _c = 1.5 which may indicate film contamination during the coating process. (paper)

[en] Co₂V_0.67Fe_0.33Al full-Heulser alloy films were fabricated on an MgO (100) single crystalline substrate by using two different heat treatments- substrate heating and post-annealing. Ultra-high-vacuum dc magnetron sputtering was used to prepare the sample. The L2₁ structure was obtained when the substrate temperature (T_s) was 500degC. For the same sample, the magnetic moment per formula unit showed the highest value of 2.4 μ_B at 5 K. There were small differences between the samples fabricated by substrate heating and post-annealing in terms of their structural and magnetic properties. A magnetic tunnel junction (MTJ) using Co₂V_0.67Fe_0.33Al as a bottom electrode was fabricated. A larger tunnel magnetoresistance (TMR) was obtained by substrate heating than post-annealing with a maximum value of 28% at RT and 50% at 5K when the Co₂V_0.67Fe_0.33Al was sputtered at T_s=500degC. We found that there is an intimate relationship between the lattice constant of Co₂V_0.67Fe_0.33Al and the TMR. (author)

[en] The crystal structures, electronic and magnetic properties of conducting molecular magnets developed in our group are reviewed. (DMET)₂FeBr₄ is composed of alternating stacks of quasi-one-dimensional (1D) donor sheets and square lattice magnetic anion sheets. This salt undergoes an SDW transition of the donor layer at 40 K and an antiferromagnetic transition of Fe³⁺ spins on the anion layer at 3.7 K. The one-to-one correspondence of the anomalies appearing on the magnetization curves with those on the magnetoresistance supports the presence of the π-d interaction. (EDO-TTFI₂)₂[M(mnt)₂] (M=Ni,Pt) consists of 1D chains of conducting donors and magnetic anions aligned in parallel. These salts show metallic conductivity accompanied with a metal-insulator transition around 90 K. Localized spins on the anions behave as a 1D ferromagnet, whose origin is explained by McConnell's first model. The properties of related materials, (EDTDM)₂FeBr₄, (EDS-TTF)₂FeBr₄ and (EDO-TTFBr₂)₂FeBr₄, are also presented

[en] The sexual development of the fungus Phycomyces is inhibited by light. The action spectra for this photoinhibitory effect were determined for 48 h continuous exposure between 350 and 700 nm wavelengths during the mating process. Effective wavelengths were shorter than 490 nm, but the most effective wavelengths depended on the stage of sexual development. In early stages of progametangium formation, the major peaks appeared near 360 nm with small shoulders at 410nm, but in later stages, after gametangium formation, only single peaks were detected in the UVA range (350-390 nm). Low-fluence irradiation in the later stage, however, revealed inhibitory effectiveness at 370-410 nm, implying the existence of a dual photoresponse and multiple regulatory systems in the mating process of Phycomyces. (author)