[en] Emulsion chambers composed of lead plates and nuclear emulsion plates were exposed to mono-energetic electron beams at Fermilab. Some effects were studied on the shower development arising from geometrical spacing between lead and emulsion and from inclination of incident electron beams. The results are i) dilution effect is fairy well expressed by the theoretical curves which are specified by the dilution factor. ii) Spacing effect can not be expressed by a linear function of a gap between lead and emulsion only. iii) Inclination effect is well expressed by a correction of geometrical (elliptical) approximation

[en] A 20 m² iron EX (emulsion or X-ray film) chamber has been exposed and cooperated with EAS array at Mt. Norikura since November 1980. EAS data are being recorded by the single trigger of any one of burst detectors settled under the EX chamber and also by the coincidence trigger of central density detectors. A dependence of maximum burst size/0.25 m² on EAS size is widely scattered in size range 10³-10⁷. This seems to imply a considerable amount of big burst events being originated from proton primary

[en] The Priestley-Taylor (PT) equation requires net radiation Rn as an input. A figure for Rn is often unavailable from many meteorological datasets. Rn may be estimated from downward solar radiation S and assumed Rn/S values. We examined seasonal changes of Rn/S values using 1-year radiation data observed above a coniferous evergreen plantation forest of Cryptomeria japonica. The values for Rn/S showed slight seasonal changes; however, other terms in the PT equation showed large seasonal changes. Thus, we conclude that assuming a constant Rn/S for all seasons is valid for this site

[en] A Monte-Carlo simulation has been done which includes a jet production process based on QCD theory in order to see its effect on gamma-ray families. In the present paper, jets with Pt > 4 GeV/c are considered. Many of the effects the hard scattering gives on the family are similar to those brought about by heavy primary cosmic-rays. In many of observed quantities, however, the effect is statistically insignificant. The QCD jet can contribute to increase the number of clusters in a family, whilist it is not a main source for generating double core families, though it has potential of giving double core families of the largest separation. It is also concluded that the increase of the transverse momentum with energy in the fragmentation region should be very weak. This is discussed in connection with jet production with Pt < 4 GeV/c and correlation of Pt and multiplicity. (author)

[en] The sigma epsilon gamma spectrum in 1 approx. 5 x 1000 TV observed at Mt. Fuji suggests that the flux of primary protons 10 to the 15 approx 10th eV is lower by a factor of 2 approx. 3 than a simple extrapolation from lower energies; the integral proton spectrum tends to be steeper than around to the power V and the spectral index tends to be steeper than Epsilon to the -17th power around 10 to the 14th power eV and the spectral index becomes approx. 2.0 around 10 to the 15th power eV. If the total flux of primary particles has no steepening up to approx 10 to the 15th power eV, than the fraction of primary protons to the total flux should be approx 20% in contrast to approx 45% at lower energies

[en] The effect of pO₂ atmosphere during annealing on electrical properties of spinel-type oxide composed of Mn, Co, and Ni used as a thermistor material was investigated. Sintered body of monophase spinel-type oxide with composition of Mn_1.5CoNi_0.5O₄ was prepared by oxidation and fired at 1400 deg C. Oxidation was conducted at 1100 deg C at which the spinel structure is stable. The spinel-type oxide was annealed in atmospheres of various pO₂ in the temperature range 100 to 300 deg C. The oxide was p-type semiconductor regardless of annealing conditions. The electrical conductivity and the mobility increased with increasing pO₂. Electrical conduction of the oxide was considered to be controlled by a small polaron hopping. Copyright (1998) Australasian Ceramic Society

[en] A Monte Carlo simulation of extensive air showers (EAS's) was done under a particle-interaction model and was compared with the EAS's accompanied by γ-ray and hadronic families with total energy summationE/sub γ//sub ,//sub H/ greater than 10 TeV obtained in the Mt. Norikura experiment (2780 m above sea level). The strong correlation between the shower size N/sub e/ of EAS's with family and the primary energy, E₀, was obtained from the simulation as E₀/N/sub e/ = (2.0/sub -0.7//sup +2.7/) GeV with 95% width. The flux of the EAS's with family is sensitive to the chemical composition, especially to the fraction of protons in the primary cosmic-ray particles. The fraction of protons is inferred to be (20 +- 6)% and (23 +- 9)%, with one standard deviation (1σ), at energy (1.4/sub -0.5//sup +1.9/) x 10/sup 15/ eV and (2.8/sub -1.0//sup +3.8/) x 10/sup 15/ eV with 95% confidence interval, respectively, under the assumption of increasing cross section σ/sub p//sub -air/proportionalE/sup 0.055/ and approximate Feynman scaling in the fragmentation region. These values are in agreement with the values obtained from other mountain emulsion-chamber experiments within 2σ. The proton fraction thus obtained, around 20%, is much less than the normal abundance (∼40%) expected from direct observations at lower energies around 10/sup 12/ eV

[en] The experimental data of extensive air showers (EAS) accompanied by gamma-families, with total energy greater than 10 TeV, were compared with a Monte Carlo simulation with a rising cross section proportional to E sup 0.04 for the p-air inelastic cross section. It is found that the absolute intensity of the size spectrum of such EAS is strongly affected by the primary protons intensity at 10 to the 15th power approx. 10 to the 16th power eV region, and the experimental size spectrum agrees with the simulated spectra for the p-poor primary composition better than the p-rich one

[en] Five emulsion chambers were analyzed with two different dilution factors exposed to the 50-, 100-, and 300-GeV electron beams at Fermi National Accelerator Laboratory. The longitudinal development and lateral distribution of the number of shower tracks within a certain radius ( < or = 100 μm) both roughly agree with the theoretical transition and lateral curves by Nishimura and Kidd connected by a spacing factor equal to the dilution factor. The error of the cascade energy measurement by the conventional way, using the transition curves within a radius 50 μm, is 18--28 % for 50 --100 GeV and 13--14 % for 300 GeV. Track length within a cylinder of the same radius gives less ambiguity than the above method, when the track length is summed up till the depth is greater than 1.4 times the depth of the maximum number of shower tracks within a radius 50 μm. Other results with details are also described

[en] Floating-type reduction-nitridation of spherical zirconium oxide (ZrO₂) powder, which had about 50nm size, was continuously carried out at 1250 to 1550 deg C in N₂-NH₁-C₆H₆ gas, and ultra-fine zirconium nitride (ZrN) powders having 50nm size were obtained above 1350 deg C. The residence time Of ZrO₂ particles at reduction-nitriding temperature range was estimated to be a few seconds. These ZrN powders had high electrical conductivity and good sinterability. It was found that the formation mechanism of ZrN consisted of several elementary reaction process; deposition of carbon film at ZrO₂ particle, reduction-nitridation of the particle by the carbon film and NH₃. From the above formation conditions and the properties of resultant ZrN powder, the synthesis method designed in this work is considered to be advantageous compared to conventional methods. Copyright (2000) The Australian Ceramic Society