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International audience; Ice polymorphs show extraordinary structural diversity depending on pressure and temperature. The behavior of hydrogen-bond disorder not only is a key ingredient for their structural diversity but also controls their physical properties. However, it has been a challenge to determine the details of the disordered structure in ice polymorphs under pressure, because of the limited observable reciprocal space and inaccuracies related to high-pressure techniques. Here, we present an elucidation of the disordered structure of ice VII, the dominant high-pressure form of water, at 2.2 GPa and 298 K, from both single-crystal and powder neutron-diffraction techniques. We reveal the three-dimensional atomic distributions from the maximum entropy method and unexpectedly find a ring-like distribution of hydrogen in contrast to the commonly accepted discrete sites. In addition, total scattering analysis at 274 K clarified the difference in the intermolecular structure from ice VIII, the ordered counterpart of ice VII, despite an identical molecular geometry. Our complementary structure analyses robustly demonstrate the unique disordered structure of ice VII. Furthermore, these findings are related to proton dynamics, which drastically vary with pressure, and will contribute to an understanding of the structural origin of anomalous physical properties of ice VII under pressures.

The performance of a vibration power generator using a single crystal core of Fe–Ga alloy was compared with that of a generator using a Fe–Ga alloy polycrystal core with a similar Ga concentration. When the generator using the polycrystal core was forcibly vibrated by 1-G acceleration, the vibration frequency dependence of the open-circuit voltage showed a peak with a maximum value of about 0.14 V at the first resonance frequency due to the inverse magnetostrictive effect. On the other hand, the generator using a single crystal core with a direction parallel to the external stress direction exhibited a maximum value of about 0.26 V, about two-times larger than that of the device using the polycrystal core. Consequently, a vibration energy generator using a single crystal core of Fe–Ga alloy has advantages in performance over a generator using a polycrystal core.

The structure of ζ´-Al80Mn16Co4 was analyzed using single-crystal X-ray diffraction. The diffraction pattern indicated that the ζ´-AlMnCo phase has a hexagonal unit cell with a space group P63/m, a = 30.5173(5) Å, c = 12.4742(2) Å, and the a-axis is 3 -times as large as that of the ζ-phases in the Al-Cr-Cu and Al-Cr-Ni systems. Mn atoms prefer icosahedral coordination similar to that of Cr in the ζ-phase, and the Co atoms are located in the interstitial area formed by the connection of the icosahedra. The icosahedral connection of the ζ´-phase is well characterized by the I3 cluster, a fragment of vertices sharing 3 icosahedra. The structural features of the superstructure are associated with the distribution of Co in the interstitial area.

The hydrogen desorption and absorption reactions of the complex metal hydride NaAlH4 are disproportionation processes, and the kinetics can be improved by adding a few mol% of Ti compounds, although the catalytic mechanism, including the location and state of Ti, remains unknown. In this study, we aimed to reveal the generating mechanism of catalytic Al–Ti alloy in NaAlH4 with TiCl3 using quantum multiprobe techniques such as neutron diffraction (ND), synchrotron X-ray diffraction (XRD), anomalous X-ray scattering (AXS), and X-ray absorption fine structure (XAFS). Rietveld refinements of the ND and XRD, profiles before the first desorption of NaAlD(H)4–0.02TiCl3 showed that Al in NaAlD(H)4 was partially substituted by Ti. On the other hand, Ti was not present in NaAlH4, and Al–Ti nanoparticles were detected in the XRD profile after the first re-absorption. This was consistent with the AXS and XAFS results. It is suggested that the substitution promotes the formation of a highly dispersed nanosized Al–Ti alloy during the first desorption process and that the effectiveness of TiCl3 as an additive can be attributed to the dispersion of Ti.

The performance of an adsorption system using Maxsorb III + ethanol pair is investigated for practical heat pump applications. An adsorption system using a single bed with a single evaporator/condenser is employed and the performance of the system is assessed for various regeneration temperatures (80 °C, 70 °C and 60 °C). The impact of the adsorption time on the performance of the selected pair is further evaluated. The potential application of the present adsorbent + adsorbate pair is the automobile air-conditioning system where the exhaust waste heat will be recovered to operate the adsorption system. Thus, antifreeze fluid is employed as the heat transfer medium for the adsorber and the evaporator/condenser heat exchanger. A mathematical model is developed to estimate the uptake amount from the experimental data. The sensible heat change (thermal mass), the superheating of the refrigerant in the adsorber, the adsorber heat leak and the heat rejection to the heat transfer medium are accounted for. The uptake amount is further verified using the classical p–T–q diagram. For operation using 30 °C adsorber coolant inlet and 15 °C chilled water inlet, the cooling capacity of the present system ranges from 15 to 35 W for the adsorption times of 600 s and 300 s, respectively. It is observed that the regeneration temperature significantly influences the net uptake of the system. The maximum net uptake is recorded to be about 0.995 kg/kg for the regeneration temperature of 80 °C. The system is further assessed using the ratio of the cooling capacity to the adsorption heat.

A method to obtain the quantitative lithium distribution of a lithium-ion battery cathode using laser-induced breakdown spectroscopy (LIBS) measurements is proposed. We perform LIBS measurements in a reduced argon atmosphere of 1000 Pa and use a calibration curve obtained by measuring the emission intensities at 610.4 nm of standard samples, whose atomic ratios of lithium to cobalt are 0, 0.10, 0.30, 0.51, 0.62, 0.80, and 0.99. The lithium distributions of cycled cathodes, which contain LiCoO2 as an active material, obtained by this method are relatively consistent with the Co(III) distributions obtained by X-ray absorption spectroscopy (XAS). XAS is the conventional method to quantitatively display the reaction distribution of a cathode material used in a lithium-ion battery. Additionally, LIBS can detect the precipitating decomposition products of the electrolyte, LiF, on the cathode. However, the precision of the lithium ratio using LIBS is not as good as that achieved for the Co(III) ratio obtained using XAS. Therefore, LIBS is suitable to obtain a semi-quantitative lithium distribution in a cathode of a lithium-ion battery through a much simpler procedure than XAS. Furthermore, LIBS has an advantage to detect the decomposition product of the electrolyte using laboratory-scale measurements.

Cross-sectional shape-controlled Fe-Ga alloy crystals for energy harvester applications were grown using the micro pulling down (μ-PD) method. The investigation of material concentrations along the growth direction reveals that a high growth rate of 5.0 mm/min raises the effective segregation coefficient of Ga, k eff (Ga), and ensures high concentration homogeneity. However, the high growth rate was speculated as causing non-preferentially oriented portion formation that decreases the magnetostrictive property. The magnetostriction 3/2λ = 286 ppm was achieved for a good oriented sample (i.e. the misorientations from 〈100〉 were less than 7.5°.) with the Ga concentration of 16.8 at%. A prototype vibration energy harvester using a plate-shaped Fe-Ga alloy grown at 5.0 mm/min showed comparable or superior performance to the device using commercially available alloys. By leveraging the advantages of near net-shape controlling and a higher growth rate than other crystal growth techniques, the μ-PD method is expected to emerge as a new technique for mass-producing Fe-Ga alloys as materials for energy harvester applications.

We grew large single crystals of metal nickel with a maximum diameter of 8 in. using the Czochralski (CZ) method. Characteristics of the metal material, namely, the seed elongation and intense cooling radiation at high temperatures during crystal growth, are the main challenges when growing ingots with large diameters. These problems were resolved by optimizing the parameters related to crystal growth, such as reduction of crucible and ingot rotation speed, and adjustment of shoulder formation angle of ingot shape. The produced ingots were confirmed to be single crystals by the Laue back-reflection method. Wafers were cut from single crystal ingots using a multi-wire saw with diamond abrasive grains. A smooth, mirror-like surface was obtained on the wafers by using an ordinary mechanical polishing method. The full width at half maximum values of the X-ray rocking curve of the metal nickel crystal surface significantly depends on the surface treatment method. It was found that ordinary mechanical mirror polishing introduces strain on the surface and non-uniformity of the crystal orientation.

In order to apply magnetostrictive materials in vibration energy harvesting devices, large-sized ingots of Fe–Ga alloy single crystals exhibiting large magnetostriction were successfully grown using the Czochralski method. The performance of power generation using the 〈1 0 0〉-oriented crystal has been evaluated using simply designed devices. Specifically, influences of magnetic fields produced by inverse magnetostriction of the crystal and permanent magnets on power generation have been studied. The results indicated that power generation using the Fe-Ga alloy single crystal result from the inverse magnetostriction and the magnetic fluxes generated by electromagnetic inductions, which are caused by the cyclic relative motion between a coil and permanent magnets using the simple device frame structures. It was shown that the alloy single crystal acts as a magnetic core, and that the alternating current produced via vibration energy harvesting can be converted to direct current for charging batteries.

Biomass yields and biofuel production were examined in a dual (solid and liquid)-phase cultivation system (DuPHA) with the unique filamentous cyanobacteria, Pseudanabaena sp. ABRG 5-3 and Limnothrix sp. SK1-2-1. Continuous circular cultivation was driven under the indoor closed (IC) or indoor opened (IO) conditions and provided biomass yields of approximately 8–27 g dry cell weight (DCW) floor m−2 d−1. Alkanes of heptadecane (C17H36) or pentadecane (C15H32) as liquid biofuels were also recovered from the lower liquid-phase, in which cyanobacteria were dropped from the upper solid-phase and continuously cultivated with a small amount of medium. After the main cultivation in DuPHA, the upper solid-phase of a cotton cloth on which cyanobacteria grew was dried and directly subjected to a combustion test. This resulted in the thermal power (kJ s−1) of the cloth with microalgae increasing approximately 20–50% higher than that of the cloth only, suggesting a possibility of using the solid phase with microalgae as solid biofuel.

In the present study, a novel system for the hypoxic culture of individual tissues was established for the subculturing of cell lines for research as well as for clinical culture of primary cells. To provide a hypoxic environment throughout the process of tissue handling and culture, we designed a clean bench with CO2 gas circulation and a hypoxic culture incubator containing disposable capsules. The bench top was covered with an acrylic chamber, and an atmosphere of 5.0% CO2-air was maintained using a sensor control. The cleanliness class of the chamber could easily be improved to 1 within 5 min of circulative filtration, even though it was found to be 105 before the unit was operated. Gas buffer solution (220 ml of 20 mM HEPES, 25 mM NaHCO3, pH 7.4) placed in a 500-ml plastic capsule in the unit stabilized the culture environment by functioning as a heat storage and gas pool. The inflow of air that occurred by the cap of the capsule was opened was excluded by the infusion of purging gas (5.0% CO2 and 95% N2); the O2 level returned to 2.0% within 4 min, after which the gas supply automatically switched to the culture gas (2.0% O2, 5.0% CO2, and 93% N2). If this purging process was omitted, restoration of the O2 level required 120 min, even though the inner volume was only 280 ml.

Transition metal-metalloid amorphous systems such as Fe-B and Ni-B are usually applied for the soft magnetic metallic glassy alloys and are counted as one of prominent categories in the field of amorphous alloy technology. Since glass forming ability of these systems correlates closely with the atomic level structure depending on chemical species of metal and metalloid, the local structure analysis for these glassy alloys is strongly required. In order to obtain the reliable structural model for these metal (Fe, Ni)-metalloid (B) amorphous samples, we determined the partial structural functions by combinational use of neutron diffraction (ND) and anomalous X-ray scattering (AXS). The amorphous ribbon samples were produced by the single-roller melt-spinning technique. The AXS measurements at Fe and Ni absorption edges were carried out at BL-7C of Photon Factory, KEK. The ND experiment was performed by using the time-of-flight technique and high intensity total diffractometer, NOVA at MLF, J-PARC. The figure shows the g(r)s for Fe80B20, Ni81B19, and Ni60B40calculated by the interference functions obtained by ND measurements. The dashed lines in the figure indicate the interatomic distances estimated from Goldschmidt atomic radii (Fe: 1.28 Å, Ni: 1.25 Å, B: 0.97 Å). At the nearest neighbor region up to about 3 Å, the first peak could be accounted for a harmony of metal (M)–B and B–B pair correlations and the second peak is mainly contributed by the M-M pair correlation. As for the three dimensional structural modeling of the amorphous samples, reverse Monte Carlo simulation has been performed starting from an initial model of 2,000 atoms with the b.c.c. structure. The present simulation results are found to reproduce the experimental interference functions obtained by the ND, ordinary X-ray diffraction, and AXS measurements. We will present the obtained structural model and local structural units around B including their arrangement.