We give a method for obtaining infinitely many framed knots which represent a diffeomorphic 4-manifold. We also study a relationship between the n-shake genus and the 4-ball genus of a knot. Furthermore we give a construction of homotopy 4-spheres from a slice knot with unknotting number one.

Spherical particles of ferrite (intermediate between Fe3O4 and γ-Fe2O3) were grown on seed crystals (∼9 nm) via the green rust route in an aqueous solution added with sucrose, which promotes spherical growth. By highly dispersing the seed crystals in an HNO3 solution, we could control the diameter of the particles over a wide range of 20–200 nm (geometric standard deviation: 1.1–1.4) by changing the amount of the seed crystals. At the beginning of the seed growth, clusters of the seed crystals were resolved into smaller clusters, each composed of a few seed crystals.

Effects of H2O partial pressure on ZnO crystal growth by chemical vapor transport (CVT) have been investigated. The use of H2O causes the increase in growth rate of ZnO, indicating that H2O acts as a dominant oxygen source in ZnO growth by CVT. The use of H2O also improves structural, electrical, and optical properties of the CVT-grown ZnO crystals. A sharp X-ray rocking curve for the ZnO (0002) reflection was obtained, and the full width at half maximum value was 38 arcsec. Strong near band edge emission was observed in photoluminescence spectra at room temperature. Both carrier concentration and Hall mobility increased with partial pressure of H2O. The dependence of the carrier concentration on temperature indicates that there exist two donors in the CVT-grown ZnO crystals. The estimated ionization energy for the shallow donor was 35±5 meV and that for the deep donor was 115±5 meV.

Under neutral conditions (pH=7-9) and temperature as low as 4°C we successfully synthesized ferrite nanoparticles with an intermediate structure between Fe3O4 and γ -Fe2O3 from an aqueous solution. These experimental conditions enabled us to immobilize even very unstable bioactive molecules onto the surfaces of the ferrite nanoparticles during their synthesis. The bioactive molecules were strongly fixed onto the ferrite surface intermediated by specific amino-acids or related-structure molecules each having pairs of carboxyl (COOH) groups. The COOH group pair was found to make a chemical bond with the ferrite particles. Utilizing the strong bond between such molecules and ferrites, we successfully prepared bioactive ferrite nanobeads where the ferrite nanoparticles were encapsulated in a polymer that exhibited negligible non-specific absorption of proteins. We also succeeded in fixing bioactive molecules onto the surfaces of the polymer coating of the ferrite nanobeads. We describe promising applications of our novel bioactive ferrite nanobeads such as high performance magnetic carriers for bio-screening, hypothermia, MRI contrast enhancement and magnetic drug delivery.

“Ferrite plating” is a typical “soft solution processing” (SSP) application; it enables the formation of oxide ferromagnetic films from an aqueous solution at T 24−100°C under atmospheric pressure. Using ferrite plating, we can grow crystallized ferrite films of spinel-type (MFe)3O4 (where M = Fe, Co, Ni, Zn, Al, Cr, etc.) in one step, requiring no heat treatment. This opens the door to fabricating novel ferritefilm devices using substrates of such nonheat-resistant materials as plastics and GaAs integrated circuits; conventional ferrite-film preparation techniques, such as sputtering, vacuum evaporation, molecularbeam epitaxy, liquid-phase epitaxy, and so on, require high temperatures (>∼600°C) for the crystallization of ferrites, which deteriorates the non-heat-resistant substrates. Ferrite plating is a unique technique that allows us to synthesize ferrite “films” by means of a wet chemical process. There are many techniques, for synthesizing ferrite “particles” from aqueous solutions, but no technique, to our knowledge, enables ferrite-film synthesis by a wet chemical process.

BaTiO3, SrTiO3, and BaxSr1−x TiO3 thin films, as well as multilayers in the SrTiO3-BaTiO3 system, have been prepared on Ti substrates in newly constructed flow-system equipment by the hydrothermal-electrochemical method. The synthesis parameters (temperature of 120–200 °C, flow rate of 1–50 cm3/min) allow fabrication of dense, single-phase films with different morphology by controlling nucleation and/or growth rates. The flow system enables also an easy fabrication of SrTiO3/BaTiO3 and BaTiO3/SrTiO3 multilayers with variable chemical composition and microstructure across the film thickness. The multilayers can be prepared in only one experiment by simply changing the kind of flowing solution and/or adjusting the processing conditions.