1,721,328 research outputs found
Phase sensitive amplifiers and their applications
No full textWe review recent advances on phase sensitive parametric amplifiers for all-optical signal processing and low-noise amplification. Their basic principles and practical implementations are provided with insights in the challenges ahead to further improve their performance
Diffraction and XPS studies of Cu complexes of intercalated compounds of α-zirconium phosphate. II: XPS electronic structures
No full textThe description of the crystallographic structure of Cu complexes of intercalated compounds of α-Zr(HPO4)2·H2O (α-ZrP) reported in part I of this work is implemented with an X-ray photoelectron spectroscopy study performed on the same samples. The experiments carried out at room and liquid nitrogen temperatures, show, in contrast with data previously reported, that Cu2+ ions are reduced by the Al-Kα and Mg-Kα radiations. Nevertheless, some information on the electronic structure has been achieved for those elements that are not photoreduced. In particular, the N1s core line due to the interaction of nitrogen in the phenanthroline with hydrogen in the structure has been identified, and the suppression of this interaction with the increasing concentration of copper has been demonstrated
On the non-local screening mechanisms in the 2p photoelectron spectra of NiO and La2NiO4
No full textChemical Physics Letters Volume 214, Issue 2, 29 October 1993, Pages 208-214 A study of the electronic structure of decagonal Al70Ni15CO15 quasi-crystal
No full textThe electronic structure of Al70Ni15Co15 decagonal quasi-crystal has been studied by X-ray photoelectron spectroscopy (XPS). The disappearance of the Ni2p(3d9) satellite and the decreased intensity of the 3F state in the NiL3M45M45 Auger spectra indicate a strong d-sp hybridization accompanied by the filling of the Ni3d bands. The filling of the Ni3d bands produces closed-shell type XPS spectra of the Ni core lines, while Co core line XPS spectra show that a significant amount of d holes are still localized on Co. This picture suggests that the magnetic properties are mainly determined by Co. The dispersion of the 3d holes is also responsible for the drop of the 3d states near EF but the angle integrated density of states does not exhibit a pseudo-gap. Finally, the correlation energy, UA, has been calculated from the kinetic energy of the 1G term of the NiL3M45M45 Auger emission
Time-division-multiplexing using pulse position locking for 100 Gb/s applications
Full text linkRecently, there is a great interest in pushing communication technologies to 100 Gb/s. However, there are still many challenges to perform high speed (> 40 Gb/s) clock and data recovery, and data time-division-multiplexing (TDM). Here, we propose and numerically analyze an asynchronous optical packet retimer using parabolic or sinusoidal phase modulation and linear dispersion. This scheme is named pulse position locking (PPL). Numerical simulation shows that this scheme can effectively resynchronize input signals with arbitrary delays to the local clock, and reduce input jitter. The scheme can also be applied to TDM 10 Gb/s and 40 Gb/s signals to over 100 Gb/s
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Growth and the structure of epitaxial VO2 at the TiO2(110) surface
No full textEpitaxial VO2 layers have been grown on the TiO2(110) rutile surface up to thicknesses of 5 ML. These ultrathin films have been characterized by means of x-ray photoelectron spectroscopy (XPS), x-ray photoelectron diffraction (XPD), low-energy electron diffraction (LEED), and ultraviolet photoelectron spectroscopy (UPS) measurements. LEED and XPD structural data demonstrate that the layer is both short- and long-range ordered, and that it has a rutile structure. The success in preparation of a single-crystalline epitaxial VO2 layer opens possibilities for studying the properties and the surface chemistry of this interesting oxide, so far complicated by the difficulties in growing macroscopic crystals. From the HeI spectra it turns out that the shape, position, and width of the 3d band closely resemble the UPS data of the bulk monoclinic semiconductive phase. The reported results could add new clues to a better understanding of the metal-to-semiconductor phase-transition phenomenon in VO2
Early stages of epitaxial growth of vanadium oxide at the TiO2(110) surface studied by photoelectron diffraction
No full textThis paper reports experimental evidence for an incipient epitaxial growth of vanadium oxide at the TiO2(110) surface. This finding is based on a x-ray photoelectron diffraction and low-energy electron diffraction study of a submonolayer of vanadium deposited at the TiO2(110) surface, performed after annealing at 473 K in ultrahigh vacuum conditions. The data unambiguously show that vanadium atoms occupy selected sixfold-coordinated titanium sites which underbridge oxygen atoms of the topmost layer and that the TiO2(110) long-range surface structural order is preserved
Formulazione e applicazione del giudizio di idoneità in lavoratori della sanità affetti da disturbi muscolo-scheletrici del rachide lombare
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