Benchmarking recognition results on camera captured word image data sets

We have benchmarked the maximum obtainable recognition accuracy on five publicly available standard word image data sets using semi-automated segmentation and a commercial OCR. These images have been cropped from camera captured scene images, born digital images (BDI) and street view images. Using the Matlab based tool developed by us, we have annotated at the pixel level more than 3600 word images from the five data sets. The word images binarized by the tool, as well as by our own midline analysis and propagation of segmentation (MAPS) algorithm are recognized using the trial version of Nuance Omnipage OCR and these two results are compared with the best reported in the literature. The benchmark word recognition rates obtained on ICDAR 2003, Sign evaluation, Street view, Born-digital and ICDAR 2011 data sets are 83.9%, 89.3%, 79.6%, 88.5% and 86.7%, respectively. The results obtained from MAPS binarized word images without the use of any lexicon are 64.5% and 71.7% for ICDAR 2003 and 2011 respectively, and these values are higher than the best reported values in the literature of 61.1% and 41.2%, respectively. MAPS results of 82.8% for BDI 2011 dataset matches the performance of the state of the art method based on power law transform.

Spectroscopic studies of In2O3 nanostructures; photovoltaic demonstration of In2O3/p-Si heterojunction

The thermal oxidation process of the indium nitride (InN) nanorods (NRs) was studied. The SEM studies reveal that the cracked and burst mechanism for the formation of indium oxide (In2O3) nanostructures by oxidizing the InN NRs at higher temperatures. XRD results confirm the bcc crystal structure of the as prepared In2O3 nanostructures. Strong and broad photoluminescence spectrum located at the green to red region with maximum intensity at 566 nm along with a weak ultraviolet emission at 338 nm were observed due to oxygen vacancy levels and free excitonic transitions, respectively. The valence band onset energy of 2.1 eV was observed from the XPS valence band spectrum, clearly justifies the alignment of Fermi level to the donor level created due to the presence of oxygen vacancies which were observed in the PL spectrum. The elemental ratio In:O in as prepared In2O3 was found to be 42:58 which is in close agreement with the stoichiometric value of 40:60. A downward shift was observed in the Raman peak positions due to a possible phonon confinement effect in the nanoparticles formed in bursting mechanism. Such single junction devices exhibit promising photovoltaic performance with fill factor and conversion efficiency of 21% and 0.2%, respectively, under concentrated AM1.5 illumination.

Selenium adsorption on Au(111) and Ag(111) surfaces: adsorbed selenium and selenide films

Results of a high resolution photoemission and electrochemistry study of Se adsorption Au(111) and Ag(111) surfaces performed by immersion of pristine samples into an aqeuous solution of Na2Se are presented. Cyclic voltammetry on Au shows formation of selenium adsorbed species and the structures observed in reductive desorption are to the atomic and polymeric species observed in XPS. In the case of Au(111) XPS spectra in the Se(3d) region indeed show two main features attributed to Se chemisorbed atomically and polymeric Se-8 features.' Smaller structures due to other types of Se conformations were also observed. The Au(4f) peak line, shape does not show core level, shifts: indicative of Au selenide formation the case of silver, XPS spectra for the Ag(3d) show a broadening of the peak and a deconvolution into Ag-B bulk like Ag-Se components shows that the Ag-Se is located at a lower binding energy, an effect similar to oxidation and sulfidation of Ag. The Se(3d) XPS spectrum is found to be substantially different from the Au case and dominated by atomic type Se due to the selenide, though a smaller intensity Se structure at an energy similar to the Se-8 structure for Au is also observed. Changes in the valence band region. related to Se adsorption are reported.

Hardness results for computing optimal locally Gabriel graphs

Delaunay and Gabriel graphs are widely studied geo-metric proximity structures. Motivated by applications in wireless routing, relaxed versions of these graphs known as Locally Delaunay Graphs (LDGs) and Lo-cally Gabriel Graphs (LGGs) have been proposed. We propose another generalization of LGGs called Gener-alized Locally Gabriel Graphs (GLGGs) in the context when certain edges are forbidden in the graph. Unlike a Gabriel Graph, there is no unique LGG or GLGG for a given point set because no edge is necessarily in-cluded or excluded. This property allows us to choose an LGG/GLGG that optimizes a parameter of interest in the graph. We show that computing an edge max-imum GLGG for a given problem instance is NP-hard and also APX-hard. We also show that computing an LGG on a given point set with dilation ≤k is NP-hard. Finally, we give an algorithm to verify whether a given geometric graph G= (V, E) is a valid LGG.

Corticosterone Treatment Results in Enhanced Release of Peptidergic Vesicles in Astrocytes via Cytoskeletal Rearrangements

While the effect of stress on neuronal physiology is widely studied, its effect on the functionality of astrocytes is not well understood. We studied the effect of high doses of stress hormone corticosterone, on two physiological properties of astrocytes, i.e., gliotransmission and interastrocytic calcium waves. To study the release of peptidergic vesicles from astrocytes, hippocampal astrocyte cultures were transfected with a plasmid to express pro-atrial natriuretic peptide (ANP) fused with the emerald green fluorescent protein (ANP.emd). The rate of decrease in fluorescence of ANP.emd on application of ionomycin, a calcium ionophore was monitored. Significant increase in the rate of calcium-dependent exocytosis of ANP.emd was observed with the 100 nM and 1 M corticosterone treatments for 3 h, which depended on the activation of the glucocorticoid receptor. ANP.emd tagged vesicles exhibited increased mobility in astrocyte culture upon corticosterone treatment. Increasing corticosterone concentrations also resulted in concomitant increase in the calcium wave propagation velocity, initiated by focal ATP application. Corticosterone treatment also resulted in increased GFAP expression and F-actin rearrangements. FITC-Phalloidin immunostaining revealed increased formation of cross linked F-actin networks with the 100 nM and 1 M corticosterone treatment. Alternatively, blockade of actin polymerization and disruption of microtubules prevented the corticosterone-mediated increase in ANP.emd release kinetics. This study reports for the first time the effect of corticosterone on gliotransmission via modulation of cytoskeletal elements. As ANP acts on both neurons and blood vessels, modulation of its release could have functional implications in neurovascular coupling under pathophysiological conditions of stress.

Platinum Ion-Doped TiO2: High Catalytic Activity of Pt2+ with Oxide Ion Vacancy in Ti1-x4+Ptx2+O2-x Compared to Pt4+ without Oxide Ion Vacancy in Ti1-x4+Ptx4+O2

Ti0.97Pt0.032+O1.97 and Ti0.97Pt0.034+O2 have been synthesized by a solution combustion method using alanine and glycine as the fuels, respectively. Both crystallize in anatase TiO2 structure with 15 nm average crystallite size. X-ray photoelectron spectroscopy (XPS) confirmed Pt ions are in the 2+ state in Ti0.97Pt0.03O1.97 (alanine) and 4+ state in Ti0.97Pt0.03O2 (glycine). The rate of CO oxidation occurring over Ti0.97Pt0.032+O1.97 (0.76 mu mol.g(-1).s(-1)) is similar to 10, times more than that over Ti0.97Pt0.034+O2 at 60 degrees C (0.08 mu mol.g(-1).s(-1)). A large shift in 100% hydrocarbons conversion to lower temperature was observed for Pt2+ ion-substituted TiO2 relative 10 that for Pt4+ ion-substituted TiO2. After reoxidation of the reduced compound by H-2 as well as CO, Pt ions are stabilized in mixed valences, 2+ and 4+ states. The role of oxide ion vacancy has been demonstrated by CO oxidation and H-2 + O-2 recombination reactions in the presence and absence of O-2. We analyze the activated lattice oxygens upon substitution of Pt2+ and Pt4+ ions in TiO2, using first-principles density functional theory (DFT) calculations with supercells of Ti31Pt1O63, Ti30Pt2O62, and Ti29Pt3O61 for Pt2+ ion substitution and Ti31Pt1O64, Ti30Pt2O62, and Ti29Pt3O61 for Pt4+ ion substitution in TiO2. We find that the local structure of Pt2+ ion has a distorted square planar geometry and that of Pt4+ ion has an octahedral geometry similar to that of Ti4+ ion in pure TiO2. The change in coordination of Pt2+ ion gives rise to weakly bonded oxygens, and these oxygens are involved in high rates of catalytic reaction. Thus, the high catalytic activity results from synergistic roles of Pt2+ ion and oxide ion vacancy and weakly bonded lattice oxygen.

Generalized distributive law for ML decoding of STBCs: further results

The problem of designing good Space-Time Block Codes (STBCs) with low maximum-likelihood (ML) decoding complexity has gathered much attention in the literature. All the known low ML decoding complexity techniques utilize the same approach of exploiting either the multigroup decodable or the fast-decodable (conditionally multigroup decodable) structure of a code. We refer to this well known technique of decoding STBCs as Conditional ML (CML) decoding. In [1], we introduced a framework to construct ML decoders for STBCs based on the Generalized Distributive Law (GDL) and the Factor-graph based Sum-Product Algorithm, and showed that for two specific families of STBCs, the Toepltiz codes and the Overlapped Alamouti Codes (OACs), the GDL based ML decoders have strictly less complexity than the CML decoders. In this paper, we introduce a `traceback' step to the GDL decoding algorithm of STBCs, which enables roughly 4 times reduction in the complexity of the GDL decoders proposed in [1]. Utilizing this complexity reduction from `traceback', we then show that for any STBC (not just the Toeplitz and Overlapped Alamouti Codes), the GDL decoding complexity is strictly less than the CML decoding complexity. For instance, for any STBC obtained from Cyclic Division Algebras that is not multigroup or conditionally multigroup decodable, the GDL decoder provides approximately 12 times reduction in complexity compared to the CML decoder. Similarly, for the Golden code, which is conditionally multigroup decodable, the GDL decoder is only about half as complex as the CML decoder.

Laser- induced optical properties change in Sb10S40Se50 chalcogenide thin films: An investigation through FTIR and XPS measurements

Chalcogenide glasses are interesting materials for their infrared transmitting properties and photo-induced effects. This paper reports the influence of light on the optical properties of Sb10S40Se50 thin films. The amorphous nature and chemical composition of the deposited film was studied by X-ray diffraction and energy dispersive X-ray analysis (EDAX). The optical constants, i.e., refractive index, extinction coefficient, and optical band gap as well as film thickness are determined from the measured transmission spectra using the Swanepoel method. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. The dispersion energy parameter was found to be less for the laser-irradiated film, which indicates the laser-irradiated film is more microstructurally disordered as compared to the as-prepared film. It is observed that laser-irradiation of the films leads to decrease in optical band gap (photo-darkening) while increase in refractive index. The decrease in the optical band gap is explained on the basis of change in nature of films due to chemical disorderness and the increase in refractive index may be due to the densification of films with improved grain structure because of microstructural disorderness in the films. The optical changes are supported by X-ray photoelectron spectroscopy data. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A reexamination of some puzzling results in linearized elasticity

In this paper, we analyse three commonly discussed `flaws' of linearized elasticity theory and attempt to resolve them. The first `flaw' concerns cylindrically orthotropic material models. Since the work of Lekhnitskii (1968), there has been a growing body of work that continues to this day, that shows that infinite stresses arise with the use of a cylindrically orthotropic material model even in the case of linearized elasticity. Besides infinite stresses, interpenetration of matter is also shown to occur. These infinite stresses and interpenetration occur when the ratio of the circumferential Young modulus to the radial Young modulus is less than one. If the ratio is greater than one, then the stresses at the center of a spinning disk are found to be zero (recall that for an isotropic material model, the stresses are maximum at the center). Thus, the stresses go abruptly from a maximum value to a value of zero as the ratio is increased to a value even slightly above one! One of the explanations provided for this extremely anomalous behaviour is the failure of linearized elasticity to satisfy material frame-indifference. However, if this is the true cause, then the anomalous behaviour should also occur with the use of an isotropic material model, where, no such anomalies are observed. We show that the real cause of the problem is elsewhere and also show how these anomalies can be resolved. We also discuss how the formulation of linearized elastodynamics in the case of small deformations superposed on a rigid motion can be given in a succinct manner. Finally, we show how the long-standing problem of devising three compatibility relations instead of six can be resolved.

Multivalent Cu-Doped ZnO Nanoparticles with Full Solar Spectrum Absorbance and Enhanced Photoactivity

Full solar spectrum absorbers are widely pursued for applications related to photocatalysis and photovoltaics. Here we report multivalent Cu-doped ZnO nanoparticles which exhibit full solar spectrum absorbance and high photoactivity. Metathesis-based, green-chemical approaches with synthesis yield of similar to 100% are used. Cu incorporation in ZnO results in an increase of average solar spectrum absorbance from a mere 0.4% to 34%. On the other hand, (Zn, Cu)0 composites result in materials with up to 64% average solar spectrum absorbance. Doped systems operate well under both visible and UV illumination. The nanomaterials prepared are characterized by using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and X-ray photoelectron spectroscopy (XPS). Photocatalysts explored have particle sizes >= 50 nm. This is deliberately done in order to avoid the nanotoxic size regime of ZnO. Despite the large particle size and low specific surface area (<20 m(2).g(-1)), the best catalyst reported here compare favorably with recent reports on ZnO based systems. Using X-photoelectron spectroscopy and synthesis property correlations, we infer that the presence of multivalent Cu (most likely in the form of Cu1+delta) on ZnO surface is responsible for the observed photoactivity enhancement.

Synthesis and luminescence properties of Sm3+ doped CaTiO3 nanophosphor for application in white LED under NUV excitation

CaTiO3:Sm3+ (1-11 mol%) nanophosphors were successfully synthesized by a low temperature solution combustion method LCS]. The structural and morphological properties of the phosphors were studied by using Powder X-ray diffractometer (PXRD), Fourier transform infrared (FTIR), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM). TEM studies indicate that the size of the phosphor is similar to 20-35 nm. Photoluminescence (PL) properties of Sm3+ (1-11 mol%) doped CaTiO3 for NUV excitation (407 nm) was studied in order to investigate the possibility of its use in White light emitting diode (WLED) applications. The emission spectra consists of intra 4f transitions of Sm3+, such as (4)G(5/2) -> H-6(5/2) (561 nm), (4)G(5/2) -> H-6(7/2) (601-611 nm), (4)G(5/2) -> H-6(9/2) (648 nm) and (4)G(5/2) -> H-6(11/2) (703 nm) respectively. Further, the emission at 601-611 nm show strong orange-red emission and can be applied to the orange-red emission of phosphor for the application for near ultra violet (NUV) excitation. Thermoluminescence (TL) of the samples irradiated with gamma source in the dose range 100-500 Gy was recorded at a heating rate of 5 degrees C s(-1). Two well resolved glow peaks at 164 degrees C and 214 degrees C along with shouldered peak at 186 degrees C were recorded. TL intensity increases up to 300 Gy and thereafter, it decreases with further increase of dose. The kinetic parameters namely activation energy (E), frequency factor (s) and order of kinetics were estimated and results were discussed in detail. (C) 2014 Elsevier B.V. All rights reserved.

Effect of Post-Deposition Annealing on the Al2O3/Si(100) Interface Properties

In the present investigation, Al2O3 thin films were deposited onto Si < 100 > substrates by DC reactive magnetron sputtering. The films were annealed in vacuum for one hour at 623, 823 and 1023 K. The composition of the films was quantitatively estimated using X-ray photoelectron spectroscopy (XPS) and the O/Al ratio was found be in the range 1.19 to 1.43. Grazing incidence X-ray diffraction (GIXRD) results revealed that the annealed films are amorphous in nature. Cross sectional transmission electron microscopy (X-TEM) analysis was carried out to study the microstructure and nature of the Al2O3-Si interface as a function of post-deposition annealing. TEM results revealed the presence of nanocrystalline gamma-Al2O3 in the annealed films and an amorphous interface layer was observed at the Al2O3 Si interface. The thickness of the amorphous interface layer was determined from the TEM analysis and the results are discussed.

Determination of Internal Structures of Heterogeneous Nanocrystals Using Variable-Energy Photoemission Spectroscopy

This article describes the determination of the internal structure of heterogeneous nanoparticle systems including inverted core-shell (CdS core and CdSe shell) and alloyed (CdSeS) quantum dots using depth-resolved, variable-energy X-ray photoelectron spectroscopy (XPS). A unique feature of this work is the combination of photoelectron spectroscopy performed at lower X-ray energies (400-700 eV), to achieve surface sensitivity, with bulk sensitive measurements at high photon energies (>2000 eV), thereby providing detailed information about the whole nanoparticle structure with a great accuracy. The use of high photon energies furthermore allows us to investigate nanoparticles much larger than those studied thus far. This capability is a consequence of the much-increased mean free path of the photoelectron achieved at high excitation energies. Our results show that the actual structures of the synthesized nanoparticles are considerably different from the nominal, targeted structures, which can be post facto rationalized in terms of the reactivity of different constituents.

Facile synthesis of reduced graphene oxide/Pt-Ni nanocatalysts: their magnetic and catalytic properties

The catalytic performance of metals can be enhanced by intimately alloying different metals with Reduced Graphene Oxide (RGO). In this work, we have demonstrated a simplistic in situ one-step reduction approach for the synthesis of RGO/Pt-Ni nanocatalysts with different atomic ratios of Pt and Ni, without using any capping agent. The physical properties of the as-synthesized nanocatalysts have been systematically investigated by XRD, FTIR, Raman spectroscopy, XPS, EDX, ICP-AES, and TEM. The composition dependent magnetic properties of the RGO/Pt-Ni nanocatalysts were investigated at 5 and 300 K, respectively. The results confirm that the RGO/Pt-Ni nanocatalysts show a super-paramagnetic nature at room temperature in all compositions. Furthermore, the catalytic activities of the RGO/Pt-Ni nanocatalysts were investigated by analyzing the reduction of p-nitrophenol, and the reduction rate was found to be susceptible to the composition of Pt and Ni. Moreover, it has been found that RGO/Pt-Ni nanocatalysts show superior catalytic activity compared with the bare Pt-Ni of the same composition. Interestingly, the nanocatalysts can be readily recycled by a strong magnet and reused for the next reactions.

Synthesis and electrocatalytic properties of manganese dioxide for non-enzymatic hydrogen peroxide sensing

Manganese dioxide nanoparticles were synthesized by chemical reduction route at different growth temperatures of 40 degrees C, 80 degrees C, 100 degrees C and were characterized using X-ray Diffraction (XRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Cyclic Voltammetry (CV) and chronoamperometry (CA) analysis. FESEM results show that on increasing growth temperature the morphology changes from clusters into mixture of rods and flakes. XPS analysis reveals the formation of MnO2. Then these particles were immobilized on Pt electrode. A platinum (Pt) electrode modified with low dimensional MnO2 was investigated as a chronoamperometric (CA) sensor for hydrogen peroxide sensing (H2O2). The sample prepared at 100 degrees C shows good electrocatalytic ability for H2O2 sensing when compared with the samples prepared at 40 degrees C and 80 degrees C. At an operating potential of 0.3 V vs. Ag/AgCl catalytic oxidation of the analyte is measured for chronoamperometric (CA) monitoring. The CA signals are linearly proportional to the concentration of H2O2. It is also found that the morphology of the nanostructure plays a vital role in the detection of H2O2. (C) 2014 Elsevier Ltd. All rights reserved.