Two-scale and full-scale analyses of elastoplastic honeycomb blocks subjected to flat-punch indentation

In this study, we perform comparative two-scale and full-scale analyses of elastoplastic regular hexagonal honeycomb blocks subjected to in-plane flat-punch indentation. Zigzag and armchair types of cell arrangements are considered for the blocks; relatively thick cell walls are assumed to focus on the effect of cell wall yielding rather than cell wall deflection. For the two-scale analysis, the fully implicit homogenization scheme developed by Asada and Ohno [Asada, T., Ohno, N., 2007. Fully implicit formulation of elastoplastic homogenization problem for two-scale analysis. International Journal of Solids and Structures 44, 7261–7275] is rebuilt by introducing half unit cells to halve the analysis domains in unit cells. For the full-scale analysis, three cell sizes are considered. It is shown that the two-scale analysis provides no apparent dependence on the two types of cell arrangements because of their equivalence under in-plane loading, whereas the full-scale analysis reveals that the local deformation in honeycomb blocks is highly dependent on cell arrangement. Nevertheless, the two-scale analysis is found to be successful in predicting the indentation load-displacement relation and the macroscopic localization direction in honeycomb blocks.     

X-ray microcalorimeter based on superconducting transition edge sensors.

We have tried to realize an X-ray imaging spectrometer based on the superconducting transition edge sensor (TES) with high energy resolution, a large pixel array, a relatively high absorption efficiency and a high count rate. Our single pixel of Ir/Au TES achieved an excellent energy resolution of 9.4 eV for 5.9 keV X-rays. We have also proposed a pixellated array of Ir-TES where we slightly modify the bias point of each pixel and identify the pixel from the response function of each pixel. Our 10-pixel device, where all pixels are parallel biased, obtained 13 eV (FWHM) at 3 keV energy resolution and 80 microm position resolution. So far, we could successfully operate a 20-pixels device. Further, we are now trying to improve the count rate and the absorption efficiency of TESes, by developing our original new TES geometry which having a radiation absorber that self-adjusts the operating temperature.     

Mobility of arsenic in hot spring water accompanying its penetration into the ground

The contents of arsenic in soils collected in the Kusatsu hot spring area, Gunma, Japan, were determined by INAA, with the average content of 36 mg/kg, which was obviously higher than that reported for the Japanese crust. The remarkably high contents of arsenic, 170 and 130 mg/kg, were observed in the soils collected near the discharge point of the surplus hot spring water. The distribution of arsenic in the ground suggests that arsenic originated from hot springs has been diffusing into the ground accompanying the penetration of the hot spring water.     

Thermodynamic modeling of the system As–Fe combined with first-principles total energy calculations

A thermodynamic model has been developed for the system As–Fe by combining the Calphad approach and the first-principles total energy calculations. Our first-principles calculations are based on the projector augmented wave method within the generalized gradient approximation. We performed these calculations because the experimental values for the enthalpy of formation of the compounds As₂Fe, AsFe and AsFe₂ may have a large uncertainty. Our results indicate significantly more negative values for the enthalpy of formation of these compounds relative to the experimentally established values. We demonstrate that applying our first-principles results in a thermodynamic analysis based on the Calphad approach leads to a calculated phase diagram and thermodynamic properties which are not significantly different from experimental data.     

Inherent post-collision interaction in spectator: Auger-transitions in metals and charge-transfer systems

The inherent post-collision interaction (PCI) between an Auger-electron and a spectator electron in core-hole decay in metals and charge-transfer systems is described in a systematic maimer by a many-body theory. The inherent PCI effect on spectator Auger-transition spectral lineshapes of metals and charge-transfer systems is discussed. The spectator Auger-transition energy shift due to a change of chemical environment is discussed in the light of the inherent PCI.     

Gold(I)‐Catalyzed Cascade Cyclization Reactions of Allenynes for the Synthesis of Fused Cyclopropanes and Acenaphthenes

A gold‐catalyzed reaction of phenylene‐tethered allenynes with benzofurans gave 1‐(naphth‐1‐yl)cyclopropa[b]benzofuran derivatives, whereas the reaction of 1‐allenyl‐2‐ethynyl‐3‐methylbenzene derivatives in the absence of benzofurans gave acenaphthenes in good yields. These results can be rationalized by nucleophilic attack of the alkyne moiety on an activated allene to form a vinyl cation intermediate.