Isotope separation effect for uranium by chemical exchange had been found to be too small for practical applications. However, Japan developed recently a promising uranium en-richment process based on chemical exchange, which is an ion exchange reaction between uranous ion in an anion resin bed and uranyl ion in solution. Developement of a water-hydrogen exchange process has been eagerly anticipated as tech-nology for large scale separation of tritium. This paper reviews recent studies which have resulted in the developement of highly active hydrophobic platinum catalysts. The research concerning isotope separation in plasma has been in progress. In this area two schemes-plasma rotation and ion cyclotron resonance-show the most promissing results. However, one cannot presently be sure that these methods will lead to an economical large scale separation, because the physics is more complex than that involved in other separ-ation techniques.
The necessity and importance of the precise PVT property measurements with respect to the technically important fluids are discussed in the light of a recent demand in various applications. Some of the thermodynamic backgrounds in the thermophysical properties research as well as the conventional techniques for the PVT property measurements are reviewed. In addition, some of the practical experience in the PVT property measurements by the present author and his group are also introduced.
PbTiO3, ferroelectric thin films deposited on substrates of platinum, sapphire, fused quartz and In2O3 coated fused quartz have been fabricated by rf sputtering. Relations of crystal structure in the films with sputtering conditions, thickness and heat treatment have been investigated by means of X-ray diffraction analyses. Dielectric properties vary with the heat treatment conditions and the film thickness grown. Typical properties obtained by a 4 hours heat treatment at 800°C for 1μm film are ε≈220, tan≈4%, the remanent polarization of ≈4.8 μC/cm2 and the coercive field of ≈86.8 kV/cm. Optical transmittance of the film in the visible range is as high as 80%. The transparency and high dielectric constant of this film allow to develop low threshold voltage. EL device.
Theoretical and experimental aspects of the free electron laser are reviewed. First, the spectrum of light emitted when the high-speed electron beam is traversed through a helical wiggler is discussed. When a light pulse is travelling along with the electron beam through the helical wiggler, the electrons are forced to emit light of the same frequency. The gain of intensity of light due to this induced emission is calculated. Then, some details of the Stanford experiment to operate a free electron laser using the induced emission is presented. Finally, problems concerning the free electron laser are discussed.
A supersonic free expansion of polyatomic molecules seeded in an inert carrier gas has been regarded as an excellent technique to produce the isolated and ultracold molecules which satisfy the requirements of an ideal spectroscopic sample. The cooling effects in the supersonic molecular beam are briefly summarized. An experiment on aniline with a simple pulsed supersonic nozzle combined with a pulsed tunable UV light source is described as an example of the fluorescence excitation spectroscopy. Recent progress on the optical spectroscopy of polyatomic molecules by use of the seeded supersonic free jets is reviewed from the photochemical and the photohysical point of view. The molecular structures and the dynamical behaviors in the excited states of the stable molecules and the van der Waals complexes are discussed.
Present status of wavelength-fixed and wavelength-tunable lasers in the submillimeter-wave region is reviewed. The wavelength-fixed lasers include the discharge-pumped gas lasers and the optically-pumped gas lasers. The latter lasers have over 1, 500 lasing lines in the submillimeter-wave region, and are described in detail. The tunable submillimeter-wave lasers and coherent sources are overviewed, which are composed of semiconductor lasers, differencefrequency generators, optical parametric oscillator, two-photon mixing to generate the side band and Raman lasers. Applications of those lasers to a) the laser-isotope separation of UF6 molecules, b) the fusion-plasma diagnostics on electron density, ion temperature, etc. and c) the astronomy to detect interstellar molecules are discussed.