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We report electroplating in emulsion of supercritical carbon dioxide and electrolyte solution for the first time. Compared to conventional electroplating, this technology has advantages in covering, leveling and throwing effects on plating. Moreover the particle sizes of plated nickel are sub-100 nm.

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Magnetization vs temperature behavior of RuSr2GdCu2O8−δ (Ru-1212) measured in an field of 5 Oe, shows a clear branching of zero-field-cooled (ZFC) and field-cooled (FC) curves around 140 K, a cusp at 135 K, and a diamagnetic transition around 20 K (in the ZFC branch). The cusp at 135 K is due to the antiferromagnetic ordering of the Ru moments. The magnetization-field isotherms, below 50 K, show a nonlinear contribution from a ferromagnetic component. The resistance vs temperature behavior of the compound, in applied fields of 0, 3, and 7 T, confirms that the sample is superconducting at around 20 K. The superconducting transition exhibits field broadening of a type different than that known for conventional high Tc superconductors. The magnetoresistance (MR) is negative above the Ru magnetic ordering temperature of 135 K, while below this temperature, MR displays a positive peak in low fields and becomes negative in higher fields. A maximum of 2% is observed for the negative MR value at the Ru magnetic ordering temperature. An electron diffraction pattern obtained for this Ru-1212 sample shows two types of superstructure; one with a weak spot at the center of the a–b rectangle and the other only along the b direction. It is possible that either Ru/Cu or Ru4+/Ru5+ ordering of 2b periodicity takes place along the b direction.

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ABSTRACT:Heats of solution of blended and non-blended systems of poly(methyl methacrylate) and poly(vinyl acetate) were measured at 28°C. From the difference between them the heat of blending was estimated according to Hess's law. The absolute value for the blend prepared by freeze drying, which is thought to be molecularly mixed, was smaller than that for the blend, which shows partial phase separation. This unexpected result is explained by the differences of specific heat behaviour between the systems.KEY In a previous work,3 we have shown that compatibility determined by iJHM accords with that inferred by mechanical properties of blend film and that, for poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PV Ac), the values of ,:JHM of the solvent cast blends var_y with the conditions of preparation of the blended samples, e.g., the species of solvent used and the evaporation rate of the solvent. This behaviour is due to the different degrees of phase separation during the preparation of the blended films. In such cases, the measured heat of mixing should be called heat of blending because it reflects the degree of blending. These partially separated blends show more or less double dispersions in dynamic modules 4 around * On the other hand, we can obtain a molecularly mixed blend of PMMA and PV Ac by freeze drying, 4 which shows only one dispersion like a random copolymer or a plasticized polymer. The present work is concerned with the heat of blending and other thermal properties of the blended sample of PMMA and PV Ac prepared by freeze drying. EXPERIMENT AL MaterialsCommercial poly(methyl methacrylate) and poly(vinyl acetate) were purified by precipitation from an acetone solution with n-hexane. The molecular weights of PMMA and PV Ac determined by [ r;] were 3. 3 X 10 5 and 1.4 x 10 5 respectively. After being dried sufficiently, the weighed amounts of PMMA and PV Ac were dissolved in benzene. The concentration of total polymers in solution was about ten per cent by weight. This solution was quenched to the Dry Ice-methanol temperature and then the frozen solution was sucked by a vacuum pump to sublimate the benzene. Completion of sublimation was confirmed by a Tesla's coil. The resulting powder was then pressed under vacuum and pressure of 4000 kg/cm 2 for several