Fine particles of various metals (Mg, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Sn, Au, Pb and Bi) were prepared by evaporation in argon gas at low pressure. The evaporation was carried out in an ordinary vacuum evaporation unit using a tungsten wire basket heater, after introducing the gas into the vacuum chamber. The average particle size was controlled by changing the pressure of the argon. Particle diameter varied from about one hundred Angstoms at 1 mm Hg to a few tenths of a micron at 30 mm Hg. It was proved by electron diffraction that the particles of all the metals (except Pb) were not seriously oxidized in the air. Electron micrographs showed well defined crystal habits for some metals, e.g. hexagonal plates for magnesium and cubes for chromium. Remarkable “necklace-like arrangements” were observed for particles of the ferromagnetic metals. Many electron micrographs and diffraction patterns are reproduced to show the size, shape, arrangement and state of oxidation of the particles.
Equations of non-ideal Alfvén eigenmodes in stellarator plasmas are derived that take into account the finite ion Larmor radius, the parallel perturbed electric field and dissipative mechanisms. On the basis of these equations, it is shown for the first time that there exist kinetic mirror-induced Alfvén eigenmodes-modes associated with the presence of the mirror Fourier harmonic in the equilibrium configuration (the harmonic that dominates the magnetic field of the optimized stellarators of the Wendelstein line). Destabilization of these modes by fusionproduced α-particles in a Helias reactor is considered.
The synchronous dynamics of complex networks of pulse-coupled bursting neurons with heterogeneous coupling is studied. The results reveal that the generation and the stability of the completely synchronous state in such networks only depends on the input weight of each neuron, which is independent of the network structure. If the input weight is heterogenous in the networks, then a subgroup of bursting neurons, each having the same input weight, can be in almost completely synchronous states, and different subgroups with different input weights can be in burst synchronous states. The stability of this input weight determined synchronization is numerically studied by Lyapunov exponents, and the results show that the complete or burst synchronization in any complex neuronal networks is fully determined by the input weight of each neuron.c EDP Sciences Article published by EDP Sciences and available at http://www.edpsciences.org/epl or http://dx.
The intensity profile of equal thickness fringes due to 200 reflection was studied by the photographic method. The orientation of the specimen crystal was systematically changed by use of a tilting stage in the electron microscope. The real part of 200-Fourier coefficient and the imaginary part of the mean inner potential were determined to be V200
r
=7.43±0.11 volt and V0
i
=0.58±0.04 volt, respectively, provided no simultaneous reflection took place. When the deviation from the exact Bragg position, viz. the Bethe's parameter W, was varied, the behavior of intensity profile was found to be entirely different from that predicted by the two-beam approximation of the dynamical theory assuming the phenomenological complex potential. It was shown that the so-called anomalous transmission in the case of electrons can not be ascribed to the decrease of effective absorption coefficient at the Bragg position.
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