320 research outputs found
STRUCTURAL – PARAMETRIC ANALYSIS AND SYNTHESIS OF GLASS FURNACE CONDITION OBSERVER
A modified Kalman filter of the glass cooking process is synthesized, taking into account perturbations in the form of a sequence of colored noises. The possibility of expanding this filter by noise filters to improve functioning in the presence of low-frequency disturbances is studied and a corresponding estimation scheme with additional noise filters is proposed. The results of the simulation allow us to assume that low-frequency disturbances in the glass furnace act at the input and affect the state of the control object
Janus Monolayer Transition Metal Dichalcogenides
A novel crystal configuration of sandwiched S-Mo-Se structure (Janus SMoSe)
at the monolayer limit has been synthesized and carefully characterized in this
work. By controlled sulfurization of monolayer MoSe2 the top layer of selenium
atoms are substituted by sulfur atoms while the bottom selenium layer remains
intact. The peculiar structure of this new material is systematically
investigated by Raman, photoluminescence and X-ray photoelectron spectroscopy
and confirmed by transmission-electron microscopy and time-of-flight secondary
ion mass spectrometry. Density-functional theory calculations are performed to
better understand the Raman vibration modes and electronic structures of the
Janus SMoSe monolayer, which are found to correlate well with corresponding
experimental results. Finally, high basal plane hydrogen evolution reaction
(HER) activity is discovered for the Janus monolayer and DFT calculation
implies that the activity originates from the synergistic effect of the
intrinsic defects and structural strain inherent in the Janus structure.Comment: 22 pages, 12 figure
Graphene-zinc oxide based nanomaterials for gas sensing devices
Herein, we report the preparation of a hybrid material by combination of
modified graphene and ZnO. The morphological and compositional analyses
of the obtained material have been performed by means of scanning
electron microscopy and energy dispersive X-ray analysis. The functional
properties of the prepared structures have been investigated for their
application in gas sensor devices. The gas sensing performance of the
hybrid material show that the structure can be used for fabrication of
chemical sensors, as well as in electronic nose technology. (C) 2016 The
Authors. Published by Elsevier Ltd
A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors
A hybrid nanostructure based on reduced graphene oxide and ZnO has been
obtained for the detection of volatile organic compounds. The sensing
properties of the hybrid structure have been studied for different
concentrations of ethanol and acetone. The response of the hybrid
material is significantly higher compared to pristine ZnO
nanostructures. The obtained results have shown that the nanohybrid is a
promising structure for the monitoring of environmental pollutants and
for the application of breath tests in assessment of exposure to
volatile organic compounds
Weyl-Gauge Symmetry of Graphene
The conformal invariance of the low energy limit theory governing the
electronic properties of graphene is explored. In particular, it is noted that
the massless Dirac theory in point enjoys local Weyl symmetry, a very large
symmetry. Exploiting this symmetry in the two spatial dimensions and in the
associated three dimensional spacetime, we find the geometric constraints that
correspond to specific shapes of the graphene sheet for which the electronic
density of states is the same as that for planar graphene, provided the
measurements are made in accordance to the inner reference frame of the
electronic system. These results rely on the (surprising) general
relativistic-like behavior of the graphene system arising from the combination
of its well known special relativistic-like behavior with the less explored
Weyl symmetry. Mathematical structures, such as the Virasoro algebra and the
Liouville equation, naturally arise in this three-dimensional context and can
be related to specific profiles of the graphene sheet. Speculations on possible
applications of three-dimensional gravity are also proposed.Comment: 22 pages, 3 figures - two new references and few typos fixed, matches
published version by Annals of Physic
Hybrid Copper-Nanowire-Reduced-Graphene-Oxide Coatings: A Green Solution Toward Highly Transparent, Highly Conductive, and Flexible Electrodes for (Opto)Electronics
This study reports a novel green chemistry approach to assemble copper-nanowires/reduced-graphene-oxide hybrid coatings onto inorganic and organic supports. Such films are robust and combine sheet resistances ( 70%) that are rivalling those of indium-tin oxide. These electrodes are suitable for flexible electronic applications as they show a sheet resistance change of <4% after 10 000 bending cycles at a bending radius of 1.0 cm, when supported on polyethylene terephthalate foils. Significantly, the wet-chemistry method involves the preparation of dispersions in environmentally friendly solvents and avoids the use of harmful reagents. Such inks are processed at room temperature on a wide variety of surfaces by spray coating. As a proof-of-concept, this study demonstrates the successful use of such coatings as electrodes in high-performance electrochromic devices. The robustness of the electrodes is demonstrated by performing several tens of thousands of cycles of device operation. These unique conducting coatings hold potential for being exploited as transparent electrodes in numerous optoelectronic applications such as solar cells, light-emitting diodes, and displays
Studies on the mechanical stretchability of transparent conductive film based on graphene-metal nanowire structures
Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances. Here, we present hybrid nanostructures as stretchable and transparent electrodes based on graphene and networks of metal nanowires, and investigate their optical, electrical, and mechanical properties. High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study. We believe that these results suggest a substantial promise application in future electronicsopen1
Hybrid crystalline-ITO/metal nanowire mesh transparent electrodes and their application for highly flexible perovskite solar cells
Here, we propose crystalline indium tin oxide/metal nanowire composite electrode (c-ITO/metal NW-GFRHybrimer) films as a robust platform for flexible optoelectronic devices. A very thin c-ITO overcoating layer was introduced to the surface-embedded metal nanowire (NW) network. The c-ITO/metal NW-GFRHybrimer films exhibited outstanding mechanical flexibility, excellent optoelectrical properties and thermal/chemical robustness. Highly flexible and efficient metal halide perovskite solar cells were fabricated on the films. The devices on the c-ITO/AgNW- and c-ITO/CuNW-GFRHybrimer films exhibited power conversion efficiency values of 14.15% and 12.95%, respectively. A synergetic combination of the thin c-ITO layer and the metal NW mesh transparent conducting electrode will be beneficial for use in flexible optoelectronic applications
Transition metals on the (0001) surface of graphite: Fundamental aspects of adsorption, diffusion, and morphology
In this article, we review basic information about the interaction of transition metal atoms with the (0001) surface of graphite, especially fundamental phenomena related to growth. Those phenomena involve adatom-surface bonding, diffusion, morphology of metal clusters, interactions with steps and sputter-induced defects, condensation, and desorption. General traits emerge which have not been summarized previously. Some of these features are rather surprising when compared with metal-on-metal adsorption and growth. Opportunities for future work are pointed out
- …