Ferroelectric oxide crystals for light modulation and second harmonic generation, such as LiTaO3, LiNbO3, Ba2NaNb5O15 and so on, are reviewed from the standpoint of optical in-homogeneities. First, various inhomogeneities and defects stemming from crystal growth, crystal treat-ments such as heat treatment and poling procedures, and off-stoichiometry are described. Various methods proposed for controlling these inhomogeneities are discussed. Second, effects of optical inhomogeneities mainly due to compositional variation on characteristics for light modulation and second harmonic generation including the influence of thermal-induced effects are theoretically and experimentally discussed. Finally, laser-induced refractive index inhomo-geneities, so called optical damage, are surveyed and our studies on the optical damage in LiTaO3 are described, stressing on the poling procedure and the presence of oxygen vacancies.
As in a previous report5) non-absorbing light scattering in polystylene latex dispersion solution are computed using Mie theory and Hartel's treatment. In this report numerical information on possible limits of concentration of dispersion solution for applying Mie theory's treatment are presented. Particles of four diameters ranging from 0.1 to 1.5μ, five kinds of concentration ranging from 1.0×10-7 to 1.0×10-3g/g, and eleven path lengths ranging from 0.1 to 5.0mm are selected for computing the light scattering using light of wavelength 0.5461×.
The influences of inert gas additives on the oscillation characteristics at 7, 588 and 4, 924Å in the He-Zn hollow cathode laser were investigated using an improved laser tube. An increase in laser power at 7, 588 Å has been observed at higher than normal optimum zinc vapor pressure, when xenon of nearly 1% to the optimum helium pressure (about 13 torr) is mixed. In view of the various spectroscopic examination, it is infered that the increase in laser output power at 7, 588 Å is due to the enhancement of population density in the laser upper level (5p2P03/2) by Penning-type collision with enhanced He(n=3, 4) atom density, through some processes such as the second-kind collisions between the Xe(1s5) metastable and zinc ground-state atoms and collisions between the Zn(4p3P00, 2) and He(23S) metastable atoms. Also, it is to be considered that the decrease in threshold current at 4, 924 Å with the addition of krypton, especially in the relatively low zinc vapor pressure region, is attributable to an increase in zinc vapor density by the sputtering action of krypton ions.
Movable tube mass flowmeters with two constant volume flow apparatus were reported in previous papers. The flowmeter, here reported, needs only one constant volum flow apparatus, and is accordingly superior to the previous ones. It is shown theoretically that the movable tube mass flowmeter with a single constant volume flow apparatus must satisfy the following conditions: cosθA/SA=-cosθB/SB=cosθC/SC (1) where SA, SB and SC are the crosse-sctional areas of the straight tubes A, B and C which serve for the inlet or outlet of the movable tube; θA, θB and θC are the angles between the outward direction of each axis of the three straight tubes and the direction of displacement of the movable tube. The fluid of constant volume flow rate flows through the tube C. In case of the following set of values of θA, θB and θC, the construction of the mass flowmeter becomes particularly simple: θA=θC=π, θB=0. (2) As with the previous flowmeters, the measuring principle of the present flowmeter is independent of Bernoulli's theorem and the mass flow rates can be calculated theoretically without having to determine the discharge coefficient experimentally. Experiments were carried out by using two kinds of trial flowmeter of the above mentioned construction and the experimental results agree fairly well with the theory.
The adsorption state of the CO-W system at 300K has been studiedwith the FEM method. It is assumed that seven types of intrinsic sites whose structures are not dependent on the crystallographic plane exist on the semispherical surface of a b.c.c. crystal and that CO interacted with each intrinsic site has the adsorbate-surface distance which depends on the crystallographic plane. These assumptions seem to interpret the observed FEM images, and it is concluded that there exist at least seven types of adsorption states for this system.