面向医疗市场的新型微片式钽电容

随着钽技术继续向前发展,无源元件制造商们正在钽电容方面取得进展.人们需要元件外形尺寸变得更小,而且对那些需要钽器件的很多应用来说,极高的可靠性也是一个关键性的考虑.……     

Asymptotic Stability of a Class of Linear Discrete Systems with Multiple Independent Variables

This paper investigates the problem of asymptotic stability for a class of linear shift-invariant discrete systems with multiple independent variables. We establish the equivalence of this problem and that of robust stability for a class of ordinary linear shiftvarying discrete systems with the matrix uncertainty set defined by the coefficient matrices of the original system. On the basis of this equivalence, by using the variational method and Lyapunovs second method, necessary and sufficient conditions for asymptotic stability are obtained in different forms for the class of systems considered. The parametric classes of Lyapunov functions which define the necessary and sufficient conditions of asymptotic stability are determined. We use the piecewise linear polyhedral Lyapunov functions of the infinity vector norm type to derive an algebraic criterion for asymptotic stability of the given class of discrete systems in the form of solvability conditions of a set of matrix equations. A simple sufficient condition of asymptotic stability is also obtained which becomes necessary and sufficient for several special cases of the discrete systems under consideration.     

AC Induction Motor Torsional Vibration Consideration?A Case Study

Much has been written on the application of high-speed (3600 r/min) motors to pumps and compressors relative to vibration and lateral critical speeds. A reciprocating compressor coupled to an induction motor is a complex torsional system and can present a more complex set of problems to the equipment suppliers because of the wider range of forcing frequencies present. The problems encountered on a specific application with the objective of developing guidelines to be used to avoid similar system torsional problems on the application of induction motors to reciprocating equipment are discussed.     

Elastic and plastic contributions to X-ray Line broadening of InGaAsP/InP Heterostructures

The coherency state of MOCVD grown InGaAsP/InP double-heterostructure wafers was examined and their effects on the structural properties were determined in this study. Lattice mismatches were measured using {511} asymmetric and (400) symmetric x-ray reflections. The chemical lattice misfit and the elastic strain were also calculated. Misfit dislocations were examined by both x-ray topography and photoluminescence imaging. The x-ray full width at half maximum (FWHM) varied with the degree of mismatch. The largest FWHM was obtained for samples containing the misfit dislocations. It was found that FWHM is influenced not only by the plastic deformation, but also by the elastic strain. To model the dependence of the FWHM, the radius of curvature was measured, and its contribution to the x-ray line broadening was calculated. Also, the contribution from misfit dislocations was taken into account. This model assumes that the dislocations are planar and interact weakly with each other. Good agreement between measured and calculated values was obtained. Thus, it is concluded that the major contribution to x-ray line broadening ofelastically strained sample is the lattice curvature induced by misfit strain, and that the dominant factor affecting x-ray FWHM ofplastically deformed sample is lattice relaxation induced by misfit dislocation.     

Safety and security of programmable network infrastructures

Safety and security are two reliability properties of a system. A “safe” system provides protection against errors of trusted users, while a “secure” system protects against errors introduced by untrusted users. There is considerable overlap between mechanisms to support each property. Requirements for rapid service creation have stimulated the development of programmable network infrastructures, where end users or service providers can customize the properties of a network infrastructure while it continues to operate. A central concern of potential users of such systems is their reliability and, most specifically, their safety and security. In this article we explain the impact the network service model and architecture have on safety and security, and provide a model with which policies can be translated into restrictions of a general system. We illustrate these ideas with the Secure Active Network Environment (SANE) architecture, which provides a means of controlling access to the functions provided by any programmable infrastructure     

New Acceleration Principle of Charged Particles for Electronic Applications. The General Hierarchic Description

A new principle of acceleration of changed particles and quasineutral plasma beams is proposed and theoretically substantiated. The essence of this new acceleration principle is die utilization of EH-undulated fields, which resemble those of EH free-electron laser pumping systems. Here the charged particles are moving in a superposition of crossed magnetic and electric vortex undulated fields (EH-accelerator). The advantage of such systems is that both negative (electrons) and positive (ions) charged particles are accelerated simultaneously in the same longitudinal direction. In addition to the concept of the EH-accelerators, a new theoretical approach (the theory of hierarchic oscillations and waves) is given further development here. This approach has been used as a basis for the general nonlinear theory of the EH-accelerators and some other similar isochronous electronic devices with long-time interactions. In addition, several new calculation methods are presented, including the method for nonlinear current density calculations (called the averaged current-density equation hierarchic method) and two versions of hierarchic asymptotic algorithms for the integration of Maxwell's equations.     

Did a local distribution company procure prudently during the California electricity crisis?

To manage cost risk, prudent procurement of electric power requires that some portion of a buyer's energy demand be met through long-term contracting. Under cost-of-service regulation or performance-based regulation, a local distribution company (LDC) should be allowed to fully recover all prudently incurred power procurement costs. However, the regulatory test of prudence is an ex post review with the threat of disallowance. This paper presents an economic analysis of procurement prudence involving a small LDC, Bear Valley Electric Service (BVES), which serves a resort area in Southern California. The key findings are: (a) high and volatile prices and rolling blackouts characterized the market environment faced by the owner of BVES, Southern California Water Company (SCWC), at its signing of a 5-year fixed price contract; (b) SCWC was a price-taker with no incentive to act imprudently; (c) the contract was obtained via a competitive bidding process; (d) the contract price was comparable to the benchmark price of contemporaneous contracts; (e) the fixed price contract was economic when compared to available alternatives; and (f) despite (a)–(e), a negotiated settlement with the state regulator and a large user resulted in substantial disallowance. The policy implication is that a regulator should approve a prudent procurement plan proposed by an LDC to remove the unreasonable risk of an ex post review. If the LDC strictly adheres to the plan, the resulting electricity purchases are per se prudent and should entitle the LDC to full cost recovery.     

Should Russia increase domestic prices for natural gas?

Previous analyses of Russia's dual pricing system and hidden subsidies for natural gas, have neglected to assess the dual pricing system as a domestic environmental policy. If dual pricing is considered as a policy to reduce conventional air pollutants, it is more than economically justified in Russia on the basis of avoided health risks. In the short term, the substitution of coal for natural gas may result in significant additional human health risk, which translates into economic damage. An alternative abatement possibility is expensive and unlikely enforceable, due to weak environmental regulation. The authors conclude that while the price differential can be expected to diminish over time, as Russia increasingly moves to a market economy, in the near-term, dual pricing of natural gas remains the most efficient environmental policy for Russia.     

On Chiroptical Spectroscopy of Turbid Media with Optically Soft, Large Spherical Particles

The influence of the size of particles on the circular dichroism and optical rotatory dispersion spectra of turbid layers with globules of chiral substances is studied. Simple equations for large chiral particles with the refractive index close to the refractive index of the surrounding medium are obtained and analyzed. Formulae derived can be used for the solution of the inverse problem, namely for obtaining intrinsic spectra of substances inside small particles from measurements of spectra for turbid layers.     

The aquathermolysis of heavy oil from Riphean-Vendian complex with iron-based catalyst: FT-IR spectroscopy data

In this paper, we investigated the influence of steam treatment on structural group composition of resins and asphaltenes of heavy oil. The object of investigation was oil-saturated rocks from Riphean-Vendian complex. The extracted crude oil was determined as a high-viscous fluid. The resins and asphaltenes destructed in a small extent due to thermal treatment. The oil-soluble iron-based catalyst intensified the destructive processes. The content of sulfur compounds (-SO) in resins and asphaltenes drastically decreased due to reduction reaction of sulfoxide to sulfide and hydrogen sulfide. The results showed that catalytic aquathermolysis, even at low temperature ranges, promoted the cracking reaction of most macromolecular components and increased the content of light fractions of heavy oil. Consequently, it reduced its viscosity.