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161.
基于TVS二极管的电气特性和全自动引线键合机的工作环境,设计了一种RS422通信接口的保护电路,并对限流电阻、接地连接、PCB布线和器件布局提出了一些原则性要求,最后对保护电路进行抗电子打火干扰实验。实验结果表明该保护电路的保护效果明显,可以避免接口电路被损坏。 相似文献
162.
Ryszard Piasecki 《Physica A》2009,388(12):2403-2409
An entropic measure for the analysis of grey level inhomogeneity (GLI) is proposed as a function of length scale. It allows us to quantify the statistical dissimilarity of the actual macrostate and the maximizing entropy of the reference one. The maximums (minimums) of the measure indicate those scales at which higher (lower) average grey level inhomogeneity appears compared to neighbour scales. Even a deeply hidden statistical grey level periodicity can be detected by the equally distant minimums of the measure. The striking effect of multiple intersecting curves (MICs) of the measure has been revealed for pairs of simulated patterns, which differ in shades of grey or symmetry properties only. In turn, for evolving photosphere granulation patterns, the stability in time of the first peak position has been found. Interestingly, the third peak is dominant at initial steps of the evolution. This indicates a temporary grouping of granules at a length scale that may belong to the mesogranulation phenomenon. This behaviour has similarities with that reported by Consolini, Berrilli et al. [G. Consolini, F. Berrilli, A. Florio, E. Pietropaolo, L.A. Smaldone, Astron. Astrophys. 402 (2003) 1115; F. Berrilli, D. Del Moro, S. Russo, G. Consolini, Th. Straus, Astrophys. J. 632 (2005) 677] for binarized granulation images of a different data set. 相似文献
163.
This work describes how to generate and design a novel current-mode biquad filter model using tunable multiple-output operational transconductance amplifiers and grounded capacitors (MO-OTA-Cs) for synthesizing both transmission poles and zeros. Transfer functions of low-pass, band-pass, high-pass, notch and all-pass are realized based on the filter model. The theory focuses mainly on establishing a relationship between the cascaded MO-OTA-Cs and the multiple-loop feedback matrix, which makes the structural generation and design formulas. All the filter architectures contain only grounded capacitors, which can absorb parasitic capacitances and require smaller chip areas than floating ones. The simulation results are also presented to confirm the theoretical analysis. 相似文献
164.
165.
Sook Voon Yap Robert M. Ranson Wayne M. Cranton Demosthenes C. Koutsogeorgis Gary B. Hix 《Journal of luminescence》2009,129(5):416-422
This research is aimed at developing an optical sensor for remotely measuring human skin temperature in electromagnetically hostile environments, such as within a magnetic resonance imaging (MRI) scanner. In this feasibility study, various concentrations of europium-doped lanthanum oxysulphide (La2O2S: Eu—0.1-15 mol% (m/o)) and terbium-doped lanthanum oxysulphide (La2O2S: Tb—0.005-50 m/o) have been investigated in terms of crystallinity, photoluminescent (PL) spectral and decay time characteristics. For both phosphors, X-ray diffraction (XRD) has shown that as dopancy increases, the (1 0 0) and (0 0 2) reflections merge and there is a reduction in the c-axis parameter as well as the crystallite size. Photoluminescent characterisation (337 nm excitation) has also shown a dependency to dopant concentration through variance of peak intensity. Temperature dependent decay time measurements were carried out over a low temperature range 5-60 °C. Optimum brightness of these temperature dependent lines is achieved at concentrations of 1 and 10 m/o for La2O2S: Eu and La2O2S: Tb respectively. However, optimum temperature dependency is achieved at lower concentration for La2O2S: Eu, specifically at 0.1 m/o. In comparison to conventional phosphor temperature dependent characteristic, La2O2S: Tb showed an increase in decay time with respect to temperature for concentrations above 2 m/o. 相似文献
166.
The tunable nature of lasers provides for a wide range of applications. Most applications rely on finding available laser wavelengths to meet the needs of the research. This article presents the concept of compositional tuning, whereby the laser wavelength is designed by exploiting nonstoichiometry. For research where precise wavelengths are required, such as remote sensing, this is highly advantageous. A theoretical basis for the concept is presented and experimental results in spectroscopic measurements support the theoretical basis. Laser operation nicely demonstrates the validity of the concept of designer lasers. 相似文献
167.
P. T. Jochym K. Parlinski A. M. Oleś 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(2):173-179
The magnetization distribution, its energetic characterization by the
interlayer coupling constants and lattice dynamics of (001)-oriented
Fe/Pt multilayers are investigated using density functional theory
combined with the direct method to determine phonon frequencies.
It is found that ferromagnetic order between consecutive Fe layers is
favoured, with the enhanced magnetic moments at the
interface. The bilinear and biquadratic coupling coefficients between Fe
layers are shown to saturate fast with increasing thickness of
nonmagnetic Pt layers which separate them. The phonon calculations
demonstrate a rather strong dependence of partial iron phonon
densities of states on the actual position of Fe monolayer
in the multilayer structure. 相似文献
168.
We introduce the notions of a pre--set and a pre-V-set in a topological space. We study the fundamental properties of pre--sets and pre-V-sets and investigate the topologies defined by these families of sets. 相似文献
169.
Belmesnaoui Aqzzouz 《Applied Categorical Structures》2002,10(6):603-616
We define the -product of a -space by a quotient Banach space. We give conditions under which this -product will be monic. Finally, we define the
c
-product of a Schwartz b-space by a quotient Banach space and we give some examples of applications. 相似文献
170.
Properties of Pisot numbers have long been of interest. One line of questioning, initiated by Erdos, Joó and Komornik in 1990, is the determination of for Pisot numbers , where
Although the quantity is known for some Pisot numbers , there has been no general method for computing . This paper gives such an algorithm. With this algorithm, some properties of and its generalizations are investigated.
Although the quantity is known for some Pisot numbers , there has been no general method for computing . This paper gives such an algorithm. With this algorithm, some properties of and its generalizations are investigated.
A related question concerns the analogy of , denoted , where the coefficients are restricted to ; in particular, for which non-Pisot numbers is nonzero? This paper finds an infinite class of Salem numbers where .