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21.
V. V. Grimalsky S. V. Koshevaya Yu. G. Rapoport 《Radioelectronics and Communications Systems》2011,54(8):401-410
Superheterodyne amplification of electromagnetic waves of optical and terahertz bands in the case of three-wave interaction
in n-GaN films with the space change wave of millimeter band amplified due to negative differential resistance is studied. It
is shown that amplification of the space change wave in n-GaN films may be achieved on higher frequencies f ≤ 500 GHz than when using GaAs. The case of three-wave resonant interaction of two counter-propagating waves with the space
charge wave is considered for the waveguide on based on GaN film on dielectric substrate. It is shown that gain of electromagnetic
waves of optical band may reach 20–40 dB on the waveguide lengths of up to 100 μm. 相似文献
22.
The development of integrated automation systems for continuous production plants is a very complicated process. A variety of factors must be taken into account, such as their different components (e.g., production units control systems, planning systems, financial systems, etc.), the interaction among them, and their different behavior (continuous or discrete). Moreover, the difficulty of this process is increased by the fact that each component can be viewed in a different way depending on the kind of decisions to be made, and its specific behavior. Modeling continuous production complexes as a composition of components, where, in turn, each component may also be a composite, appears to be the simplest and safest way to develop integrated automation systems. In order to provide the most versatile way to develop this kind of system, this work proposes a new approach for designing and building them, where process behavior, operation conditions and equipment conditions are integrated into a hierarchical automation architecture. 相似文献
23.
This paper presents a supervisory control scheme based on hybrid systems theory and fuzzy events detection. The fuzzy event detector is a linguistic model, which synthesizes complex relations between process variables and process events incorporating experts' knowledge about the process operation. This kind of detection allows the anticipation of appropriate control actions, which depend upon the selected membership functions used to characterize the process under scrutiny. The proposed supervisory control scheme was successfully implemented for an oxichlorination reactor in a vinyl monomer plant. This implementation has allowed improvement of reactor stability and reduction of raw material consumption. 相似文献
24.
Heavy cold-rolling (95% reduction) of a 64Fe36Ni Invar alloy results in a decrease in magnetization and magnetic hyperfine field at the Fe nucleus, and an increase in electrical resistivity and x-ray line width. These changes are explained by a transition of iron atoms from a high volume-high spin electronic configuration to a low volume-low spin configuration during the deformation process. 相似文献
25.
A detailed analysis of the effect of chamber volume, orifice radius, orifice submergence and contact angle on quasi-static formation of bubbles is presented. It is shown, that many aspects of slow bubble formation, involving phenomena leading to various modes of the bubble release, as well as the maximum orifice diameter which sustains a bubble at equilibrium, can be explained on the basis of information on equilibrium shapes and conditions. Scaling rules enabling adoption of results for water to other liquids are also presented. 相似文献
26.
Eliezer L. Lozinskii 《人工智能实验与理论杂志》2013,25(4):321-340
A knowledge system S describing a part of real-world does, in general, not contain complete information. Reasoning with incomplete information is prone to errors since any belief derived from S may be false in the present state of the world. A false belief may suggest wrong decisions and lead to harmful actions. So, an important goal is to make false beliefs as unlikely as possible. This work introduces the notions of typical atoms and typical models, and shows that reasoning with typical models minimises the expected number of false beliefs over all ways of using incomplete information. Various properties of typical models are studied, in particular, correctness and stability of beliefs suggested by typical models, and their connection to oblivious reasoning. 相似文献
27.
28.
Hydrogen effects on the spall strength and fracture characteristics of amorphous Fe-Si-B alloy at very high strain rates 总被引:1,自引:0,他引:1
N. Eliaz Ph.D. E. Moshe S. Eliezer D. Eliezer 《Metallurgical and Materials Transactions A》2000,31(4):1085-1093
A novel approach is suggested, using laser-induced shock wave measurements to estimate the effects of cathodic hydrogen charging
on the mechanical properties and fracture characteristics of materials. This approach is applied to (1) determine the dominant
mechanism of hydrogen embrittlement (HE) in an amorphous Fe80B11Si9 alloy; and (2) estimate the effects of the high pressures involved in cathodic charging. The dynamic spall strength of an
amorphous Fe80B11Si9 alloy shocked before and after hydrogenation by a high-power laser to very high pressures (tens of giga Pascals) is measured.
The dynamic spall strength of crystalline iron is measured as well for comparison. An optically recording velocity interferometer
system (ORVIS) is used to measure the profile of the free surface velocity in time. The spall strength and the strain rate
are calculated from the measurement of the free surface velocity as a function of time. Fracture characteristics are studied
by scanning electron microscopy (SEM). The main conclusions are (1) the most reasonable mechanism of HE in the amorphous Fe-Si-B
alloy is the high-pressure bubble formation; (2) the high pressures involved in cathodic hydrogen charging or laser-induced
shock waves measurements may have similar effects on fracture characteristics; and (3) at very high strain rates, the spall
strength is determined mainly by the interatomic bonds. 相似文献
29.
30.
Staszewski R. Staszewski R. B. Jung T. Murphy T. Bashir I. Eliezer O. Muhammad K. Entezari M. 《Solid-State Circuits, IEEE Journal of》2010,45(2):276-288