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A new foaming apparatus, which can depressurize the vessel that contains polymer + gas from 100 MPa to atmospheric pressure in 50 ms, was developed to generate a high degree of supersaturation. The influences of the saturation conditions and the molecular weight of the polymer were studied with the new rapid decompression system using the polymethyl methacrylate (PMMA) - CO2 system as a model. It is found that the Sub-micron cellular structures could be produced by using the apparatus. The results confirm the effectiveness of the high degree of supersaturation achieved in decreasing the cell size and increasing the cell nucleation density of foams. Moreover, it was revealed that the cell size and the cell nucleation density do not always vary as expected as the saturation pressure is increased at the decompression rate and the saturation temperature conditions used in this work.

A new flexible thermal insulation sheet, a composite of silica aerogel with polypropylene (PP) foam, has been developed. Even though a large volume ratio of silica aerogel (97%) was included, the composite showed high flexibility. Thermal conductivity of the composite was 0.016 W/(m⋅K) at 298 K, which is as low as silica aerogel monolith. Silica aerogel flaking, which has been a problem in practical applications, is very low in this composite due to skin layers of the polymer-foam composite. A supercritical drying process for rolled sheets of the material for large-scale production is also described. Simulations of extraction of 2-propanol from a silica alcogel revealed that rolled composite sheets with small spaces between the sheet composite are able to dry in a reasonable extraction time. These findings led to effective on production of this material on a pilot industrial scale.

We investigated magnetic properties of spinel oxides Zn (Cr1-xFex)2O4 to study element substitution effects on magnetism of spin-frustrated spinel oxides ZnCr2O4 and ZnFe2O4. The present study revealed that an antiferromagnetic order of ZnCr2O4 (TN ~ 13 K) is suppressed by Fe doping. Zn (Cr1-xFex)2O4 with x = 0.1, 0.5, and 0.7 exhibits spin-glass-like behavior below ~ 10 K. On the other hand, Zn (Cr1-xFex)2O4 with x = 0.3 exhibits the absence of magnetic order or spin-glass-like behavior down to low temperature (3 K), which is probably due to the competition of geometrical and bond frustrations.

A two-step foaming process was developed that uses different temperatures in each step and combines ultra-high saturation pressure (Ps > 50 MPa) and rapid depressurization (> 1.25 GPa/s) for production of nanocellular polymer foams. The effect of process conditions were investigated using polymethylmethacrylate (PMMA) and carbon dioxide. Foams with small cells ( 1015 nuclei cm−3) were obtained, which were of a finer structure than those made by previous one-step foaming process. N0 tended to increase even at Ps =100 MPa. A fine cell structure (30.5 nm ± 10.4 nm) was observed with scanning transmission electron microscopy (STEM), and was confirmed when two-step process conditions were used. The process and advantages of ultra-high pressure are discussed with regard to porosity, cell size and N0.

In situ neutron diffraction during tensile deformation was performed on a steel with ferrite grain size 3.6 μm, which was close to the achievable minimum size for a ferrite - pearlite structure. The lattice plane strain, microstrain related to dislocation density, and the size of coherently diffracting blocks related to dislocation cell size were determined from the profile analysis of (110) diffraction spectra, as a function of the applied stress. The change in lattice plane strain revealed that grain refining strongly influences 'grain to grain yielding' behaviour with respect to Luders deformation. The increase in dislocation density estimated in the uniformly extending regime was similar to that observed in another specimen with ferrite grain size 46.2 μm.

A flow-type cell was developed for measuring Compton scattering spectra of heat-sensitive aqueous solution. Compton scattering spectra of water and ethanol were measured in the region from ambient conditions to 623 K and 20 MPa. Compton profiles derived from measurement with the flow-type cell were comparable with those in the literature. Results obtained from the flow-type cell showed that delocalization of electronic charge density of water and ethanol at high temperatures occurred. Delocalization of the electronic charge density of ethanol was greater than that of water at high temperature, which is consistent with the prior works that use proton NMR chemical shifts to describe hydrogen bonding.

A laser-Doppler vibrometer was used to measure the vibration of a vibrating tube densimeter for measuring P-V-T data at high temperatures and pressures. The apparatus developed allowed the control of the residence time of the sample so that decomposition at high temperatures could be minimized. A function generator and piezoelectric crystal was used to excite the U-shaped tube in one of its normal modes of vibration. Densities of methanol-water mixtures are reported for at 673 K and 40 MPa with an uncertainty of 0.009 g/cm3.