Frequency dependent Shubnikov-De Haas oscillations in Si-MOS-FET under high magnetic fields

The quantum oscillations in the AC magnetoconductance was studied for inversion layers in Si-MOS-FETs under high magnetic fields at 1.5 K. Each peak in the Shubnikov-de Haas oscillation was found to be remarkably sharpened with increasing frequency up to 50 MHz. It was also found that the width of the gate voltage for non-conductive region (σ_xx=0) increases with increasing frequency.     

Existence of double-pinning force maxima for a single pinning mechanism

Critical current measurements on a cold rolled Pb₆₀In₄₀ foil show two pinning maxima, one close to H_c2 in the neighborhood of h = 0.95, and the other at low fields around h = 0.15. The high field pinning force maximum shifts to lower fields, and the low field maximum shifts to higher fields with increasing pinning strength. The data is explained in terms of Kramer's pinning force model incorporating Brandt's expression for C>₆₆.     

Electrical transport in electron beam irradiated polyacetylene

Electrical conductivity of non-doped (CH)_x decreases a little and its activation energy increases a little by the electron beam irradiation. The increase of the electrical conductivity of the irradiated (CH)_x by I₂ doping is not so remarkable compared with that of non-irradiated (CH)_x. The conductivity of heavily irradiated (CH)_x is very low even after halogen dopings.On the other hand, the effect of the electron beam irradiation on the conductivity of previously I₂ doped (CH)_x is much less compared with that doped after the electron beam irradiation. These results are explained tentatively by the role of I₂ molecules in the initial stage of radiolysis and the suppression of the cross-linking.     

Density of states at each carbon layer of K-intercalated HOPG compounds --- high resolution 13C NMR experiment ---

We have observed high resolution ¹³C NMR spectra in k-intercalated stages 2, 3, 4 and 6 HOPG compounds. The sample was a block itself or sliced one of HOPG. From T₁T of each resolved line we obtained a distribution of density of states N(E_F) at the Fermi level among the graphite layers.     

Monte Carlo simulation of thermalization process of sputtered particles

The transport process of sputtered particles in plasma sputter deposition was studied by computer simulation using the Monte Carlo method, with particular attention to the understanding of the thermalization process. Due consideration was taken of the momentum loss as well as of the energy loss of sputtered particles colliding with sputter gas molecules. The results clearly showed that with increasing target-substrate distance, the energy distribution of sputtered copper atoms arriving at the substrate shifts toward lower kinetic energies, but still contains a considerable fraction of high energy particles. In addition, it was found that the arrival rate of sputtered copper atoms at the substrate decreases exponentially with the target-substrate distance, while the return rate to the target first increases and then becomes constant. It was concluded that the present Monte Carlo simulation can be successfully used for a quantitative estimation of the transport process of sputtered particles.     

A model for the plane to plane variations in catalytic activity seen during nitric oxide decomposition on platinum

Previous work has shown that the reactivity of platinum for nitric oxide decomposition varies significantly with the geometry of the exposed surface of the platinum. Here, the available data are compared to the predictions of a model, which is based on conservation of orbital symmetry and a simplified picture of the band structure of the surface. The model predicts that the (100) face of platinum should be more active than either the (111) or the (110). The (410) should be more active still. These predictions agree with recent experiment. The model makes several other predictions which need to be tested experimentally. These results suggest that symmetry conservation methods, similar to the ones developed by Woodward and Hoffmann for organic reactions, could yield many valuable insights into the relative activity of various catalyst structures.     

ON THE EXTERIOR SOLUTIONS OF A CHARGED MASS POINT IN GAUGE THEORIES OF GRAVITATION

In a case of spherically symtric and static field, exterior solutions of a charged mass point for the nine-parameter R+R² gravitational theories are investigated. We obtain results as follows: in the case of coupling constant (zP-2r+s)=0, solution without torsion is the Reissner-Nordstrom metric; otherwise there is no solution with vanishing torsion.     

摩托罗拉8位HC08微控制器系列

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Recovery from control plane failures in GMPLS‐controlled optical networks

The health status of the control plane and the data plane of a GMPLS‐controlled optical network is independent in the physically separated control network implementation. In most control plane designs, besides the topology information, the entities of the routing protocol only record the number of available wavelengths on each link. However, the status of each wavelength is maintained by the entities of the signalling protocol. Without recovery ability of the signalling protocol CR‐LDP, a failure in the control plane will result in the permanent loss of the status information of wavelengths. A mechanism to recover the status information of the wavelengths is proposed. A downstream node maintains a label information database (LID) about assignable (free) labels in each incoming link. A copy of LID is redundantly stored in the upstream node as a label information mirror (LIM). A systematic procedure is proposed to synchronize the contents of a LIM and the corresponding LID. The initialization of a new LDP session with the enhanced recovery mechanism will guarantee the revival of the status information of wavelengths. It can recover multiple control channel failures, but it only applies to single node failure among any pair of adjacent nodes. © Crown copyright 2002. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.     

An adaptive load balancing scheme for web servers

This paper describes an overload control scheme for web servers which integrates admission control and load balancing. The admission control mechanism adaptively determines the client request acceptance rate to meet the web servers' performance requirements while the load balancing or client request distribution mechanism determines the fraction of requests to be assigned to each web server. The scheme requires no prior knowledge of the relative speeds of the web servers, nor the work required to process each incoming request. Copyright © 2002 John Wiley & Sons, Ltd.