Space observations in extreme ultraviolet region have been continuedfor more than twenty years since the biginning of 1946. Our knowledge of the sun, stars, and the earth's upper atmo-sphere has been increased remarkably from these observations based on the technical breakthroughs that made the work possible. In this paper, typical instruments and observations are reviwed on solar spectra, spectroheliograms, and line profiles as well as the airglow, and emission spectra from the stars. Some problems for techniques conecting with space observations are described. Present situation and future problems for space reseach in Japan are also discussed.
In this paper a study is made of annular apertures with primary spherical aberration, using the Zernike polynomials. The three-dimensional intensitydistributions in meridional sections of diffraction images of annular apertures with primary spherical aberration have been evaluated for various combinations of spherical-aberration values and central-obstruction ratios, and illustrated inthe diagram showing lines of equal light intensity. The intensity distributions are briefly discussed. A further increase in the focal depth is obtained by the introduction of spherical aberration as compared to the annular aperture withoutaberration.
This report describes experimental observations of a shock wave propagating through a collision-less magnetized plasma. The magnetized plasma was produced by a linear Z pinch discharge and driven by a conical gun. A sharpshock front appeared, the thickness of which was 2 cm and smaller than the mean collision free path of 8 cm. The magnetic Mach number changed from 1 to 4. In a certain region of plasma which was defined by initial number density, magnetic field intensity and gas atomic number, the shock front had an oscillatory structure. This region seems to correspond to a collisionless shock domain. In such a shock wave, dispersion properties of magnetoacoustic waves and collisionless turbulent dissipation of energy (turbulent heating) become significant. A Rogowski probe detected the drift electrons flowing along the shock front across the magnetic field. These electrons seem to excite the two-stream instability which growsfinally into turbulence. A soft X-ray burst was caught by a Be-foil, Cal (Tl) scintillatorand a photomultiplier. This seems to endose the existence of turbulentheating process.
Doped single crystals of VO2/ M were prepared by a modified oxychrolide decomposition method, where M stands for Ti, Nb, Si, Ge and Sn. X-ray observation revealed that all the samples show MoO2 type structure at room temperature as with undoped VO2. Resistivity ρ and thermoelectric power η were measured between 100° and 400°K on several doped crystals. The values of ρ and η change abruptly at transition temperature Tt as in the case of undoped VO2. Increase of Tt was observed with VO2 containing Si, Ge and So, while decrease of Tt was observed with Nb or Ti. In terms of Adler's and Hanamura's model the shifts of Tt seem to be caused by the lattice distortion introduced with dopants.
Tin films of thickness ranging from 100Â to 5000Â deposited onto Liquid-nitrogen-cooled substrates of soda lime glass were found to be continuous even after warming to room temperature if the warming was done in the presence of dry oxygen at a pressure of 1 Torr to avoid agglomeration. The electron diffraction experiments showed that tin films less than 1000Â thick had a preferedorientation with C axis parallel to the substrate. The variation of the superconducting critical temperature Tof of tin films with filmthickness d was obtained by the relation _??_ where Tcb is the critical temperature of bulk tin. The sharp increaseof the critical temperature with decreasing film thickness is interpreted to bedue to theappearance of the prefered orientation in this films.
The spectral response, open circuit voltage, short circuit current, maximum power and the changes of matching load resistance in P/N, N/P-type silicon solar cell, damaged at room temperature by γ-ray irradiation, were measured. These changes suggest the decrease of minority carrier life time by the introduced recombination centers under γ-irradiation. Minority carrier life time in bulk region were estimated by comparing maximum response wave length obtained ex-perimentally with the calculated values. The normalized values of minority carrier diffusion length and the proportional factors of defect introduction rate, Δ(1/τ)=1/τγ-1/τ0, were obtained from the changes of short circuit current. The changes of both the diffusion length and Δ(1/τ) in P/N-type cell were larger than those in N/P-type, which were found to depend on the density of acceptor as dopant in P-type bulk region.
Image formation in Fourier-transform holography is theoretically andexperimentally treated from the viewpoint of partial coherenece. The effects of partially spatial coherence on the Fourier-transform holography are studied. It becomes clear that a reconstructed image is degraded accor-ding to the degree ofspatial coherence. A new method of measuring spatial coherence of illumi-nating light is proposed by means of Fourier-transform holography. Experimental resultsconcernedwith the image degradation and the measurement of spatial coherence arepresented.
The aim of this paper is to measure quantitatively the degree of spatial coherence across the beam of a multi-mode laser after propagation in a random medium and, by analyzing the obtained spatial coherence, to obtain information on the characteristic parameters of the random medium. A method has been proposed and experimentally used, which is based on ensemble-averaging, by means of an electric technique, over instantaneously fluctuating interference patterns produced by thedouble pinhole experiment.