一种适合VoIP电话应用的低成本PoE接口

本文介绍了Power Integrations(PI)开发的一种适用于电话上的以太网供电(PoE)分立接口电路,可帮助OEM厂商满足其设计和成本目标.     

Noise reduction in directional signals using multiple morse wavelets illustrated on quadrature Doppler ultrasound

The use of multiple complex-valued Morse wavelets for the scalogram study of signals which are unidirectional at any time, but are bidirectional overall is considered. These wavelets are well-suited to identifying the forward and reverse components. Scalogram averaging which is possible due to the multiplicity of the complex-valued wavelets leads to a scalogram with reduced noise. Information from positive and negative scales can then be used to estimate a final "cleaned" scalogram. Quadrature Doppler ultrasound blood flow in the femoral artery is taken as an example to clearly illustrate the noise reduction.     

Semi-transparent blotches removal from sepia images exploiting visibility laws

This paper presents a novel model for the removal of semi-transparent blotches on the digitized copy of sepia archive photographs. As these defects cannot be successfully eliminated by conventional interpolation methods, a proper combination of a novel visual distortion and multiresolution analysis is used for performing user-independent detection and restoration. Extensive experimental results and comparative studies show the potential of the proposed model in terms of visual quality and computational complexity.     

MOCVD Growth of Erbium Monoantimonide Thin Filmand Nanocomposites for Thermoelectrics

We report the growth of erbium monoantimonide (ErSb) thin films on indium antimonide (100) substrates by low-pressure metalorganic chemical vapor deposition. The growth rate of ErSb thin films shows strong dependency on the growth temperature and the Sb/Er precursor molar flow rate ratio. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffractometry (XRD) were employed to study the ErSb thin films grown under the growth conditions that gave the maximum growth rate in the range we investigated. We also report the growth of two types of nanocomposites in which ErSb nanocolumns or nanoslabs with lengths ~500 nm and diameters 20 nm to 30 nm are embedded in Zn-doped InGaSb (ErSb/InGaSb:Zn) and ErSb nanoparticles with diameters of ~30 nm are embedded in Zn-doped InSbAs (ErSb/InSbAs:Zn). These nanocomposites were intended to increase phonon scattering in a mid-to-long phonon wavelength range to reduce lattice thermal conductivity. We used time-domain thermoreflectance to measure total thermal conductivity for the two types of nanocomposites, obtaining 4.0 ± 0.6 W/mK and 6.7 ± 0.8 W/mK for the ErSb/InAsSb:Zn and ErSb/InGaSb:Zn nanocomposites, respectively, which suggests that the thermal conductivity was close to or slightly smaller than the alloy limit of the two ternary alloy hosts. The two nanocomposites were further studied by transmission electron microscopy (TEM) to reveal their microscopic features and by XRD to assess their crystalline structures.     

Solution Processable Monosubstituted Hexa‐Peri‐Hexabenzocoronene Self‐Assembling Dyes

Molecular organization behavior and visible light absorption ability are important factors for organic materials to be used in efficient bulk heterojunction solar cells applications. In this context, a series of monosubstituted fluorenyl hexa‐peri‐hexabenzocoronene (FHBC) are synthesized with the aim to combine the self‐association property of the FHBC unit with broadened light absorption of a small molecule organic dye, bisthienylbenzothiadiazole (TBT). Optical and electrochemical properties of the FHBC compounds vary according to their structures. Introduction of a TBT unit into the FHBC system broadens the absorption. All of the FHBC compounds show strong π–π intermolecular association in solution. X‐ray scattering measurements on thermally extruded filaments and thin films showed ordered alignment of these compounds in the solid state. In atomic force microscopy experiments, nanoscale phase separation is observed in thin films of FHBC and fullerene derivative blends. Solar cell devices with these compounds as donors are fabricated. FHBC compounds with the TBT unit show higher short circuit current while the high open circuit voltages are maintained. With C₆₀ derivative as acceptor, power conversion efficiency of 1.12% is achieved in the unoptimized solar cell devices under simulated solar irradiation. The efficiency was further improved to 1.64% when C₇₀ derivative was used as the acceptor.     

A Content Analysis of Print News Coverage of Media Violence and Aggression Research

We conducted a content analysis of news articles (N = 540) to examine whether news coverage of media violence accurately reflects scientific knowledge about exposure to media violence and its effects on viewer aggression. The analysis revealed that over the past 30 years, news articles generally suggested that a link between media violence and aggression exists. However, the tone shifted sharply back toward a neutral conclusion since 2000. This shift may be attributable to the type of medium discussed (e.g., television vs. video games), the number of unaffiliated sources that are cited in the news article, and the sex of the journalist. Implications for how this news coverage may influence news readers are discussed.     

New cubane MOCVD precursors for gallium sulphide and gallium selenide: Synthesis of [(Et2MeC)GaS]4 and [(Me2EtC)GaS]4: Structural determinations of [(Et2MeC)GaS]4 by X-ray diffraction and [(tBu)GaSe]4 by electron diffraction

The gallium sulphide cubane compounds [(Me₂EtC)GaS]₄ and [(Et₂MeC)GaS]₄, have been synthesised, and their potential as MOCVD precursors for GaS is discussed. The molecular structure of [(Et₂MeC)GaS]₄ has been determined by X-ray diffraction. In addition, the vapour phase structure of the GaSe precursor, [(^tBu)GaSe]₄ has been determined by gas phase electron diffraction and is compared with that previously determined in the solid state by X-ray diffraction.