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Diamond films produced by Ar/H/sub 2//CH/sub 4/ RF induction plasmas have high growth rates but often lack uniformity across the substrate. In this paper, the diamond growth on a probe-like molybdenum substrate, 4.76 mm in diameter, is correlated with the location of the probe in the plasma flame. Optical emission spectroscopy is used to characterize the plasma during deposition. The differences in gas temperature and electron density between the central and the outer region of the flame, as well as the variations in heat flux to the substrate at the different positions, are well reflected in the formed deposit. It is shown that uniform growth can only be expected within the homogeneous core of the plasma. The paper also addresses the gas phase boundary layer above the growing film. Spatially resolved emission spectroscopy measurements of concentration evolution inside the boundary layer region are made possible by the small dimensions of the substrate. A decrease in thermal boundary layer thickness from approximately 4.5 to 3 mm induced by an increase in plasma power enhances the lateral growth of the individual diamond crystallites and improves surface coverage. The typical film thickness growth rate of 70 /spl mu/m/h is, however, not seen to be affected.

Vacuum arc spot movement on various graphite cathode materials is investigated. The dependence of the arc spot velocity on physical, mechanical and electrical properties of the different cathode materials is measured in the presence of a variable magnetic field. It is shown that the cathode spot velocity is larger on cathodes having large grain size, low electrical resistivity and higher apparent density. The spot velocity is lower for cathodes having larger pore sizes and total porosity.

In this work, the dependence of the cathode erosion rate on vacuum arc spot velocities and cathode pore size are investigated for four types of graphite under an external variable magnetic field. Different graphite cathode properties show varying erosion rates, indicating that each graphite type should be treated as a different material. Increasing the spot velocity through an increase of the magnetic field intensity on a given cathode material decreases the erosion rate. At given magnetic field values, cathodes having higher arc velocities show an increase in the erosion rate. Other studies indicating that the increase in the arc spot velocity leads to a reduction in macroparticles emission indicate a possibility of increasing. The emission of the carbon ions component. A decrease in the pore size of the cathode also shows an increase in the cathode erosion rate.

The emission of microdroplets from the cathode surface in the vacuum arc ion plating deposition technique is the major drawback to the technique’s industrial use. The generation of these particles from graphite cathodes is studied in this article and correlated to the local thermal load in the cathode spot area. A pulse discharge was used for a precise control of this load. Increases in the arc current level, arc duration time, and, more generally, the local temperature of the cathode were found to increase the number and the average size of the emitted particles. Particles under these conditions also show an increase in the width of their size distributions. Increasing the distance between cathode and substrate was found to decrease the number density of particles observed on the substrate according to the solid angle covered. The microdroplets show a graphite structure and diameters between 0.2 and 2.0 μm. Conditions needed to decrease the number of particles emitted to the substrate are given.

Experimental data on the dependence of titanium erosion rate on cathode temperature, Ar, and N/sub 2/ pressure from vacuum to 1 torr and arc motion are presented. Erosion rate is found to decrease with conditions that promote cathode poisoning/contamination. Higher cathode temperatures result in enhanced nitriding (poisoning), leading to a reduced erosion rate. A critical nitrogen pressure (0.001 torr) exists where a sharp drop in erosion is measured. Steered arcs show lower erosion rate values of 38 and 15 /spl mu/g/C for argon and nitrogen, when compared to random arc values of 45 and 35 /spl mu/g/C. Erosion rate studies on TiN-coated cathodes show a low value of around 22 /spl mu/g/C.

Proton Exchange Membrane fuel cells (PEMFCs) have two major hurdles to overcome before they may be commercially viable: cost and operating life. Platinum (Pt) catalyst represents the bulk of the PEMFC cost and is in finite supply, but functionalized carbon nanomaterials have been identified as potential replacements for Pt cathode catalyst. This work's objective is to produce graphene nanoflakes (GNFs) and dope them with nitrogen in pyridinic sites through a second treatment step. An inductively-coupled thermal plasma (ICP) is used to dissociate methane at very high temperatures, with GNF nucleation commencing shortly after by way of rapid quenching. In a post-treatment, nitrogen doping occurs by manipulating plasma conditions and nitrogen precursor selection. Nitrogen doping up to 33.4 at.% has been demonstrated which, to our knowledge, more than doubles the largest reported amount.

Summary form only given. This project relates to the creation of a specific carbon structure for the replacement of Pt catalyst by a non-noble metal such as Fe functionalized on the carbon support1. Pt-nanoparticles are typically used as catalyst materials in a large series of applications, for example in the development of polymer electrolyte membrane fuel cells (PEM-FC) as electrical energy sources for the car industry. One main limiting factor in the demand scale up is the availability and increasing price of Pt. Iron atoms dispersed at the atomic level directly on carbon nanoparticles using nitrogen coordination mimicking the blood structure proved recently to have activities that can rival Pt-based catalyst; the stability of this complex however is lacking and high crystallinity of the support structure proved to strongly improve this parameter.

International audience; In this paper, we summarize the 2nd Book Structure Extraction competition run at ICDAR 2011. Its goal is to evaluate and compare automatic techniques for deriving structure information from digitized books, which could then be used to aid navigation inside the books. More specifically, the task that participants are faced with is to construct hyperlinked tables of contents for a collection of 1,000 digitized books. This paper reviews the setup of the competition, the book collection used in the task, and the measures used for the evaluation. It further presents the outcome of the competition: an additional ground truth of 513 book tables of contents, contributed by 6 institutions, and the result performance of the 4 participating research teams.

We are interested in supporting users in a real world application, that of troubleshooting malfunctioning office devices, such as printers or copiers. Basing upon findings from case studies of troubleshooting activities that we conducted, we are constructing a Mixed Reality troubleshooting system. The system allows end-users to try to solve the problem they are experiencing with the device by themselves, with online support available on the device, or by collaborating with a remote troubleshooter. The architecture of the system is centered on a 3D representation of the device augmented with status data of the actual device coming from its internal sensors. The 3D representation is provided to the end-users on the device screen and to the remote troubleshooters on their desktops and it offers a number of means to interact with it providing help for troubleshooting the device. The main purpose of this paper is to illustrate a new interaction mode with the virtual representation for the end-users that we are designing for our system and that is based on the use of a detachable device screen.Copyright © 2011 by ASME

In this paper we will present a set of experiments using large digitalized collections of books to show that logical structures can be extracted with a good quality when working at document level. The proposed solution relies on a twofold method: first specific logical elements are recognized by a given method. Then models for the recognized elements are generated by combining layout, content and labeling information. Model inference is made possible at document level, a level which promotes frequent occurrences of document structures. These inferred models combining several kinds of information are used to correct noisy data, typically zoning, OCR and labeling errors produced by previous processing steps. This method is illustrated by the detection of two document structures: page numbers and chapter headings, two navigating elements required by digital libraries.

The effects of N2 and CO contaminants in atmospheric-pressure argon on an arc rotating between two concentric copper electrodes has been studied using optical spectroscopy of copper lines. The axial temperature of the magnetically driven arc in Ar + %N2 was determined to be around 10,000 K for arc currents of SO to 200 A. The diffusion process of the copper vapor from the cathode was also studied. A copper density maximum 1 mm from the cathode along the arc column was found in Ar + %N2. Removal of the contaminated cathode surface layers by the arc when contaminant injection in the plasma gas was stopped was found to be a slow process with a time scale depending on the type of the gas contaminant. The presence of gas contaminant in the electrode material controls the cathode erosion mechanism and the overall arc behavior in the transition between a contaminated to a pure argon arc.

Measurements of the wall current collected from the expanding cathodic arc plasma are reported as a function of angle to cathode plane normal, with hydrogen gas pressure in the arc chamber varying between 10/sup -4/ torr and 10 torr and distance R to the cathode varying between 10 and 80 mm. The angular distribution of the collected current is not seen to be affected by the gas pressure in the chamber. This flux decreases with distance to the cathode as R/sup -(1.4)/ in vacuum and R/sup -4/ in the 1-10 torr pressure domain. Flux intensity evaluated as a function of NR, where N is the number density of hydrogen in the chamber, leads to an evaluation of an effective collision cross section, sigma /sub e/, of 0.2*10/sup -16/ cm/sup 2/ for the C/sup +/-ion/H/sub 2/ molecule interaction. This value can be attributed to the reaction C/sup +/+H/sub 2/ to CH/sup +/+H and agrees with a velocity of the C/sup +/ ions following a shock wave interaction model. >

Murphy and Good general theory for electron emission from metal surfaces was used to predict the field-emission capabilities of ideal arrays of vertically aligned carbon nanotubes (VACNT). The Nottingham effect was taken into account in order to explain experimental observation of a localized cooling of the VACNT tips during field emission and the total destruction of very short emitters at strong currents. Our model allowed to match the current, voltage and observed breaking points of individual VACNT reported in two separate experimental studies.

We present here the XRCE participation to the Structure Extraction task of the INEX Book track 2009. After briefly explaining the four methods used for detecting the book structure in the book body, we explain how we composed them to address the book structure task. We then discuss the Inex evaluation method and propose another measure together with the corresponding software. We then report on each individual method. Finally, we report on our evaluation of the results of all participants.

Results on the vacuum arc deposition (VAD) of thin carbon films on silicon, tungsten, and nickel are presented for different hydrogen pressures in the arc chamber. Raman and Auger electron spectroscopy and SEM analysis show that a large variety of film structures can be obtained. Highly oriented pyrolytic graphite is formed at high hydrogen pressure and low substrate temperature. Vacuum deposition resulted in a diamondlike structure. Evidence of the presence of multicrystalline spheres of diamond in some films is also presented. >

We present a direct method to synthesize carbon nanotubes (CNTs) on stainless steel (SS) substrates by thermal chemical vapor deposition. The method was developed with SS plates and was applied to other geometries such as meshes and powders. The procedure, which includes etching the substrate in hydrochloric acid (HCl), heat treatment for 30 minutes followed by CNT synthesis, was optimized to obtain a uniform layer of CNTs on the substrate. CNT bundled growth was also observed at certain conditions. The nanocomposite was produced by coating the CNTs with titanium nitride (TiN) in a physical vapor deposition regime.

In this paper, we revisit the problem of detecting the page numbers of a document. This work is motivated by a need for a generic method which applies on a large variety of documents, as well as the need for analyzing the document page numbering scheme rather than spotting one number per page. We propose here a novel method, based on the notion of sequence, which goes beyond any previous described work, and we report on an extensive evaluation of its performance.

Observations of the cathodic copper plasma expansion at low pressures of He, Ar, and SF/sub 6/ showed that, for background gas mass densities of rho /sub g/=1 to 4*10/sup -4/ kg/m/sup 3/ and higher, the plasma and gas are separated into two volumes. A shock wave acts as a boundary between the two volumes. The boundary attains a stationary position once its expansion velocity decreases to the velocity of sound in the background gas. This position corresponds to a distance R/sub c/ to the cathode that agrees with a snowplow expansion model, giving R/sub c//sup beta /f=E/sub r/, where f is a function of the arc current and background gas characteristics, E/sub r/ is the erosion rate of the cathode, and beta varies between 2.1 and 2.5. The interaction model is based on kinetic energy exchanges between two gas-like volumes without other energy losses. A maximum pressure limit for vacuum arc deposition is set for rho /sub g//I=2 to 9*10/sup -6/ kg/m/sup 3/ A. >

We present in this paper a method for document layout analysis based on identifying the function of document elements (what they do). This approach is orthogonal and complementary to the traditional view based on the form of document elements (how they are constructed). One key advantage of such functional knowledge is that the functions of some document elements are very stable from document to document and over time. Relying on the stability of such functions, the method is not impacted by layout variability, a key issue in logical document analysis and is thus very robust and versatile. The method starts the recognition process by using functional knowledge and uses in a second step formal knowledge as a source of feedback in order to correct some errors. This allows the method to adapt to specific documents by using formal specificities.

A thermal plasma process is described for the synthesis of fullerenes via the dissociation of hydrocarbons. The plasma reactor is equipped with a nontransferred dc plasma torch which was used to dissociate hydrocarbons. The hydrocarbons investigated include CH4, C2H2, CBrF3, CCl2F2, and C2Cl4. The best results are obtained with C2Cl4. The collection temperature of the fullerene soot in the process was found to play a critical role in the collection rate of fullerenes.

Automated collaborative filtering systems collect evaluations from users of the quality and relevance of stored information items, arch as scientific papers, books, and movies. A number of users need to give evaluations for the systems to be able to produce statistically high quality predictions of an item's interest. Promoting the creation of a rich meta-layer of evaluations is essential for these systems, but several important issues remain to be resolved. The work presented here first analyses the issues around the collection of recommendations, then proposes a set of design principles for improving and automating the collection of recommendations, and finally presents how these principles have been implemented in a real usage setting.

We present an integrated framework for the document conversion from legacy formats to XML format. We describe the LegDoC project, aimed at automating the conversion of layout annotations layout-oriented formats like PDF, PS and HTML to semantic-oriented annotations. A toolkit of different components covers complementary techniques the logical document analysis and semantic annotations with the methods of machine learning. We use a real case conversion project as a driving example to exemplify different techniques implemented in the project.

Using a networked infrastructure of easily available sensors and context-processing components, we are developing applications for the support of workplace interactions. Notions of activity and availability are learned from labeled sensor data based on a Bayesian approach. The higher-level information on the users is then automatically derived from low-level sensor information in order to facilitate informal ad hoc communications between peer workers in an office environment.

Summary form only given, as follows. Graphite cathode sources are used in arc ion plating devices for diamond-like film synthesis. A series of experimental studies and recent modeling results have been published on the problem of the detrimental co-emission of macro-particles from these sources. These suggested the emitted spherical carbon particles were a result of the local plasma conditions above the surface leading to the high pressure and temperature requirements for liquid droplet ejection, followed by a process similar to metallic electrodes. Contrary to this mechanism, this paper first presents SEM and Raman spectroscopy observations of carbon columnar growth layers formed on the cathode spot surface during the residence time of the carbon arc plasma. The emitted particles seem to originate from the cauliflower structure observed on the top layer of this growth. Cross sections of the cathode spot craters and film will be shown, with structure evolution passing from amorphous carbon at the base of the columnar structure to a dominating Raman peak of diamond at the top surface. Characteristics of the growth with varying source material morphology, their macro-particle emission behavior and arc mobility will be given together with modeling results of the plasma properties above the surface. Graphite materials showing important macro-particle emission show good correlation with decreasing spot mobility, increasing spot crater diameter and increasing growth layers. A self-sustained cathode spot model is used to evaluate the operating conditions at the plasma-surface interface.

Summary form only given, as follows. The problem of an atmospheric pressure argon plasma in contact with a floating collector is considered through the framework of the kinetic Boltzmann equation. A BGK collision term where only weak deviations from the Maxwellian velocity distribution are allowed is considered for the electron equation. This collision term for the ion is more comprehensive and accounts for large potential deviations from the Maxwellian distribution. Due to the relatively low mean energies expected, only the momentum transfer collisions are considered. The normalized Boltzmann equations are solved self-consistently with Poisson's equation using the method of fractional steps with cubic spline interpolation. The results show that the sheath region extends about 25 Debye lengths from the floating collector surface and that the sheath voltage drop is /spl sim/6.5 V. The electron current density peaks at a distance of /spl sim/9 Debye lengths while the ion current remains essentially constant from the plasma edge to the collector up to a distance of /spl sim/9 Debye lengths, and then sharply drops to zero at the collector surface. Both currents at the collector are similar in magnitude giving rise to a zero collection current. The electron velocity distribution remains very close to a Maxwellian throughout the x-space while the ion distribution shows a smooth transition from a Maxwellian at the plasma edge to a distribution showing strong ion accelerations towards negative velocities near the collector surface. Further work is in progress to extend the kinetic model to include a thermionic electron beam and aims at a kinetic description of the cathode region of high-pressure arc discharges.

Vacuum arcs are generated on dense graphite materials with enhanced local plasma density leading to strong improvement in arc mobility and stability. Observations of cross sections of the arc canyon erosion trace reveals erosion craters covered with a porous columnar film having a diamond structure. Scanning electron microscope (SEM) images of this growth structure are presented at various resolutions.

A capacitively coupled radio-frequency afterglow is used to isolate the role of electron bombardment in the degradation process of muti-walled carbon nanotubes (MWNTs). MWNTs grown on a metal substrate act as a nanostructured anode that accelerate and focus electron bombardment, facilitated by the field enhancement effect. Tip-localized MWNT degradation has been observed in scanning electron microscope images showing the progression of the MWNT degradation process. This finding is confirmed by Raman spectra. GC-MS measurements indicate that the major products of MWNT degradation are short unsaturated hydrocarbons, identified as both propyne and 1,3-butadiyne vapours. This finding is corroborated by time-resolved optical emission spectroscopy during plasma oxidation of the degradation products. Analysis of the kinetics of plasma oxidation confirm that MWNT degradation produces species consistent with thermal evaporation, such as short carbon chains, C3?C4, but not monatomic or diatomic species, C1 and C2.

This paper investigates the relationship between systems to enact software processes and systems to coordinate distributed, heterogeneous and concurrent objects. In particular, we describe in detail how one of these coordination systems systems—the “Coordination Language Facility” (CLF), developed at the Rank Xerox Research Centre—can be used to model and execute a sample software development process: bug reporting. The main advantages of using CLF are: i) language facility that allows to dynamically change both the core process model and the application-specific process templates; ii) modular architecture that allows to easily reconfigure, migrate and replicate each process component in a distributed, heterogeneous environment.

Titanium nitride has long been used for its favourable mechanical and chemical properties and it has been demonstrated that monocrystallinity in thin films enhances these properties. While the synthesis of monocrystalline thin films is well documented, common synthesis processes for titanium nitride nanoparticles yield only polycrystalline, spherically shaped powders. The process presented here allows for the synthesis of monocrystalline, cube-shaped nanoparticles by means of a dual plasma process. Pulsed electric arc erosion of a Ti cathode in a N-rich atmosphere produced by a radio-frequency discharge is used for the synthesis of the TiN nanoparticles. Electron microscopy revealed the cubic morphology of the synthesized powders and electron diffraction patterning confirmed the crystalline structure of the TiN nanoparticles.

The Murphy and Good (M?G) theory for thermo-field emission [1] was used to calculate the emission current densities over the 300?5000?K temperature range in order to bridge the gap with the simpler zero temperature version of the Fowler?Nordheim (F?N) equation. A comparison between the two sets of data reveals that the F?N equation as it is used in the analysis of F?N plots underestimates the true current density by a factor of 102 for all fields known to produce significant current in the case of carbon nanotubes arrays. We propose a new equation for field emission that is consistent with experimental current densities and that can still provide the field enhancement factor ? of field emitter arrays. This equation is obtained over the 300?3000?K temperature range by fitting the temperature and field dependences of JM?G using a f(Ts, Es, 0) function using work function values 0 of 4.5 and 2.6?eV. Our complete parametric equation for the fitted M?G current density is found to apply within a 1% error margin for f(Ts, Es, 0) functions computed for each value of 0 and for Es > 1.2 ? 109?V?m?1.

Vacuum arcs on graphite cathodes are currently used as sources of carbon ions for the production of diamond-like films in the arc ion-plating (AIP) deposition process. Emission from these cathode sources is concentrated in very localized “cathode spots” having typically 10 (i.m in diameter for graphite cathodes. These spots carry the totality of the arc current, the remaining of the surface being unaffected by the discharge. For electron emission falling in the thermo-field emission mode, extremely high current densities up to 108 -109 Am-2 are induced generating a high localized heat flux to the surface during the spot lifetime. On metallic electrodes, this strong heat flux generates localized surface melting during the microsecond scale spot lifetime. High localized plasma pressures (>10 Atm in the case of copper) were found to exist in the cathode spot volume, leading to the co-emission of micro-droplets of the liquid metal along with the ion beam.

The distribution of the current collected by a multiring anode is measured in a diffuse vacuum arc for several values of the arc current and the electrode separation. It is found that the distribution widens as the electrode separation increases. Comparison with previous measurements suggests an influence of the electrode geometry on the results.

Experimental data on the erosion rates of a copper cathode in He, Ar, and SF6 from 10-6 to 760 torr are presented. The work performed by the cathodic-erosion plasma expanding against the gas is found experimentally to be constant, the volume of the expanding plasma cloud being linked to the gas pressure by the relation R3p = constant. These data agree with a redeposition model based on condensation of the metallic vapor produced by the arc on the cathode surface. The redeposited mass on the cathode is found to be proportional to the cube root of the gas mass density.

This paper introduces an extension to PyStruct, which is an open source Python library for structured machine learning, based on general Conditional Random Field (CRF) models. We have extended it by supporting multi-type CRF to jointly classify objects of different natures, and by supporting logical constraints at prediction time. Our motivation for extending the library consists in addressing Document Understanding (DU) tasks by collectively classifying the objects present on one or several pages, jointly considering textual objects and objects of other nature like table or images or whatever object can be recognized. The logical constraints are meant to reflect prior knowledge on the DU task. We focus here on the improvement made over PyStruct, giving practical information as well. We also present a reproducible experiment. This new library is publicly available on GitHub under the Simplified BSD License.