[en] A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

[en] We have investigated the electron transport in AlGaAs/GaAs quantum well (QW) structures in real space of nanometer scale, using a scanning tunneling microscope (STM). The electrons were injected from the STM tip into a cleaved (110) surface of the QW structures at different distances along the [001] direction. Then by measuring the light emission intensity from individual QWs, two distinct decay constants were found. To understand the origin of the two decay constants, we developed a simulation model of hot electron transport in QW structures. From comparison between the experimental and calculated results, the two decay constants were identified with the thermalization length and the diffusion length of the injected electrons

[en] The protective effect of glutathione (GSH) and cysteamine (MEA) on radiation-induced mitotic delay in cultured mammalian L-5 cells was studied. Cells treated with 20 mM of GSH during irradiation with 2 Gy (200 rad) showed faster recovery of the mitotic index than control cells irradiated without chemical treatment; however, GSH had no effect on mitotic delay time. Inhibition of mitosis was observed with 80, 100, and 120 mM of GSH. Cells treated with 5 mM of MEA during irradiation also showed faster recovery of the mitotic index than the controls, but in addition the delay time was shortened. Progression of G₂-phase cells treated with 5-fluorouracil to mitosis after irradiation was protected by MEA but not by GSH. Progression of S-phase cells labeled with ³H-thymidine to mitosis was accelerated by both agents during irradiation

[en] A stable analogue of prostacyclin, iloprost, specifically bound to 30,000 x g pellet (the membrane fraction) prepared from mouse mastocytoma P-815 cells. The binding was dependent on time, temperature and pH, and absolutely required a divalent cation. The equilibrium dissociation constant and the maximal concentration of the binding site as determined by Scatchard plot analysis were 10.4 nM and 1.12 pmol/mg of protein, respectively. The Hill coefficient was 1.0, indicating a single entity of binding site and no cooperativity. The binding site was highly specific for iloprost among PGs tested (iloprost much greater than PGE1 greater than carbacyclin greater than PGE2). In contrast, the membrane fraction had the binding site specific for PGE2 and PGE1, which was distinct from the prostacyclin receptor. The dissociation of bound [3H]iloprost from the membrane fraction was specifically enhanced by guanine nucleotides. Furthermore, iloprost dose-dependently enhanced the activity of adenylate cyclase in a GTP-dependent manner. These results indicate that a specific prostacyclin receptor is coupled to the adenylate cyclase system via a stimulatory GTP-binding protein in mastocytoma cells

No abstract available

[en] We investigated the roles of vacancies and their clusters introduced in a Ti-20mass% Mo alloy by high-speed compression in the formation of aged ω-phase crystals. Specimens were deformed by a static compression mode and a high-speed compression mode, and were then aged. The relationships between morphology of aged ω-phase crystals and deformation modes are discussed along with the roles of vacancies and their clusters in the nucleation and growth of aged ω-phase crystals. Aged ω-phase crystals were found to be smaller but of higher density in a high-speed deformation specimen. These results suggest that vacancies and their clusters easily become nucleation sites of aged ω-phase crystals. Several aged ω-phase crystals in a high-speed deformation specimen were of string-like shape. High-resolution electron microscopy confirmed that the string-like crystals have the ω-phase crystal structure. One of the roles of vacancies of and their clusters introduced by high-speed deformation is considered to be relief of compressive stress, which is predicted to arise in the course of transformation

[en] Fe₄N crystals were exposed to intense electron beams at room temperature inside transmission electron microscopes (TEM) with base pressures of 10^-5-10^-6 Pa. The effects of irradiation on Fe₄N along the [0 0 1], [0 1 1], [1 1 1] and [2 1 1] orientations were investigated in situ using selected area electron diffraction (SAED), high resolution electron microscopy (HREM), and electron energy loss spectroscopy (EELS). The dose rate of the electron beam for the irradiation experiments was in the range of 0.7-2x10²⁴ e m^-2 s^-1. It was concluded that the initial Fe₄N (γ^') transformed into Fe₃O₄ (O) with the cubic-to-cubic orientation relationship of (1 0 0)_O//(1 0 0)γ^' and [0 0 1]_O//[0 0 1]γ^'. This transformation is electron-irradiation dependent, which suggests a controlled method to prepare local Fe₃O₄ crystals (magnetite) in a Fe₄N film using an electron beam

[en] Reaction intermediates in the hydrogen-exchange reaction of propene over deuterated cation-form sulfonic resin were studied by means of microwave spectroscopy. In the cases of Fe-form and Ni-form sulfonic resin, the results were explained by the process via the 2-propyl-type intermediate, while the reaction intermediate for Hg-form resin was demonstrated as an allyl-type complex. 5 figures

[en] Small stacking fault tetrahedra in gold crystals produced by the irradiation of 2 MeV electrons were observed in atomic scale by using a 100 kV high resolution electron microscope. By comparison with theoretical calculations, the smallest one observed with good contrast seems to be formed by several vacancies. Contrast anomalies which seem to be due to single vacancies were also observed and discussed by comparing with the calculated results by using a proposed model of a single vacancy. (author)

[en] Relativistic quantum field theory is applied to discuss the process of interference of white X-rays and the mechanism of rotation of the polarization of X-rays in crystals. A two-photon state is studied theoretically for analyzing the mechanism of the polarization mixing. Diffracted X-ray photons are produced by two successive stages of interaction between incident X-rays and electrons in a crystal. A dispersion relation of diffracted X-rays similar to Laue's dynamic theory is shown by use of the S-matrix. A dynamical structure factor is defined on the base of Dirac's γ-matrix. (author)