Surface Roughness Contribution to the Auger Electron Emission

Scanning Auger Microscopy (SAM) experiments have shown that z height and θ slope relative to the analysed spot are parameters that contribute to the measured Auger intensity I(z, θ). For greater analysed areas specific to Auger Electron Spectroscopy (AES), the knowledge of height and slope statistical distributions P(z) and P(θ) is required. These functions have been determined by means of profilometric data. The spatial resolution of the used tactile profilometer is similar to that which characterizes AES. A mathematical relationship I { P(z), P(θ) } has been set up for Si samples whose roughness is well defined. On the other hand, Auger images can be compared to level sections

A Contractual Approach to Investor-State Regulatory Disputes

International investment arbitral tribunals are increasingly tasked with resolving regulatory disputes. This relatively new form of dispute involves a challenge by a foreign investor to a host state’s generally applicable regulation, enacted in good faith to promote the public interest but resulting incidentally in harm to the investor’s business. Such claims typically invoke the “fair and equitable treatment” standard provided for in the bilateral investment treaty between the host state and the investor’s home state. The dominant view among commentators, and increasingly among the tribunals themselves, is that regulatory disputes should be analyzed within a public law framework, using tools derived from constitutional or administrative law. That means, for example, balancing the investor’s rights and host state’s regulatory concerns as part of a proportionality analysis. I argue that the public law approach is flawed because it requires tribunals to weigh incommensurable values and ultimately to make policy judgments when they lack the expertise and legitimacy to do so. This Article proposes that tribunals instead draw on tools from contract law and theory to approximate what the contracting states intended when they agreed to a fair and equitable treatment standard. The investment treaties themselves give no guidance on how that standard should be applied to regulatory disputes. When courts confront similar gaps in contracts, they do not simply abandon the inquiry into the parties’ intent but instead apply additional tools or principles to form the best possible estimate. The Article explores three specific tools: a default rule approach and two default standards derived from contract law’s analysis of changed circumstances. More generally, I argue that a contractual approach, by focusing tribunals on the contracting states’ intent rather than requiring them to independently assess the substance of a host state’s policy, will facilitate more principled reasoning as well as enhance the tribunals’ legitimacy, and thereby better promote the goals of international investment in the long run

Scanning Mechanical Microscopy of Laser Ablated Volumes Related to Inductively Coupled Plasma-Mass Spectrometry

Scanning mechanical microscopy based on the point by point sampling of the target surface was used to characterize volumes of minerals ablated by laser pulses (Nd: YAG, = 1064 nm, 140 μs pulse-width). Differentiated volumes resulting from vaporization and exfoliation mechanisms were selectively measured. Ablated volumes of natural pyrite (cubic FeS2), marcasite (orthorhombic FeS2) and arsenopyrite AsFeS, were transported into an inductively coupled plasma torch for subsequent mass analysis. The log of the S34 Fe57, and As75 mass intensities was linearly correlated with the log of the dimensions of the vaporized crater induced by the laser shots while large particles had no effect on the measured intensities. A memory effect for As was observed when a nylon tube was used to carry the ablated materials into the plasma torch. The memory effect was decreased by using a copper tube resulting probably from a difference in the electrical properties of the tubing systems leading to a lower adsorption of As within the copper tube than for the case of the nylon tube

Cathodoluminescence Applied to the Microcharacterization of Mineral Materials: A Present Status in Experimentation and Interpretation

Experimentation and interpretation of cathodoluminescence (CL) microscopy and spectroscopy applied to the microcharacterization of material minerals are reviewed. The origins of the intrinsic (host lattice) and extrinsic (impurities) luminescence emissions in crystals are briefly discussed. Merits and limitations of the available techniques are illustrated. CL emission changes as a function of the incident electron dose are illustrated for the case of natural quartz and sphalerite (ZnS) crystals. These effects are discussed in terms of the development of bulk charging, production of heat, diffusion of impurities, and creation of lattice defects induced by the incident ionizing particles. Although CL emission is mostly extrinsic in origin there is no general rule for identifying the nature of impurities from the CL emission spectra of minerals. However there is potential for using CL spectroscopy for trace element analysis as presented for the case of minerals containing rare-earth luminescent ions. The CL emission is a signature of the crystal-chemistry properties of minerals and hence contains potential genetic information. Some of the applications of CL emissions in the geosciences are summarized

Elimination of micropollutants in activated sludge reactors with a special focus on the effect of biomass concentration

This study aimed to investigate the effects of sludge retention time (SRT), hydraulic retention time (HRT), and biomass concentration (CTSS) in activated sludge systems on removal of various micropollutants (MPs), covering a wide spectrum of biodegradability. The influence of biomass concentration on the classical pseudo-first-order rate constant was verified. Results showed that the removal rate constants were affected by both the HRT and SRT. The enhancement of the SRT increased the removal of all the MPs except for two macrolide antibiotics. Application of a higher HRT also improved MP removal, as was expected from the measured removal rate constants. More interesting, our results indicated that, logically, the increase of biomass concentration (expressed as total suspended solids CTSS) from 3 to 5 gTSS L−1 significantly enhanced the removal rate of the highly and moderately degradable compounds. Conversely, a further increase to 8 gTSS L−1 produced only an unexpected moderate effect, showing that the rate was not proportional to biomass concentration, contrary to what is generally postulated. Therefore, the use of classical kinetic models is questionable, since they do not cover the entire range of boundary conditions in activated sludge systems. This work opens new research paths and suggests potential improvements to processe

Maximal Spontaneous Photon Emission and Energy Loss from Free Electrons

Free electron radiation such as Cerenkov, Smith--Purcell, and transition radiation can be greatly affected by structured optical environments, as has been demonstrated in a variety of polaritonic, photonic-crystal, and metamaterial systems. However, the amount of radiation that can ultimately be extracted from free electrons near an arbitrary material structure has remained elusive. Here we derive a fundamental upper limit to the spontaneous photon emission and energy loss of free electrons, regardless of geometry, which illuminates the effects of material properties and electron velocities. We obtain experimental evidence for our theory with quantitative measurements of Smith--Purcell radiation. Our framework allows us to make two predictions. One is a new regime of radiation operation---at subwavelength separations, slower (nonrelativistic) electrons can achieve stronger radiation than fast (relativistic) electrons. The second is a divergence of the emission probability in the limit of lossless materials. We further reveal that such divergences can be approached by coupling free electrons to photonic bound states in the continuum (BICs). Our findings suggest that compact and efficient free-electron radiation sources from microwaves to the soft X-ray regime may be achievable without requiring ultrahigh accelerating voltages.Comment: 7 pages, 4 figure

COMPARAISON ENTRE LES MÉCANISMES DE CORROSION ET DE FRAGILISATION INTERGRANULAIRES DES MÉTAUX PAR LES MÉTAUX LIQUIDES

Il existe peu de données relatives aux mécanismes de corrosion et de fragilisation intergranulaires des métaux par les métaux liquides. Notre but est de montrer en se basant sur des travaux personnels et des données de la littérature que tous les mécanismes se produisant aux interfaces intergranulaires (corrosion, pénétration, fragilisation) sont induits par un même mécanisme initial : l'adsorption des atomes du métal liquide sur les interfaces métalliques.Data on the intergranular corrosion mechanisms and on the intergranular embrittlement by liquid metals are scarce. Based on our own work and on the data from the literature, we have attempted to show that all the mechanisms occuring at the intergranular interfaces are induced by the same initial mechanism : adsorption of the atoms of a liquid metal on the metallic interfaces

THE EFFECTS OF SURFACE ROUGHNESS ON AUGER ELECTRON SPECTROSCOPY

Des analyses superficielles par spectrométrie Auger (AES, SAEM) montrent que la topographie de surface influence de manière conséquente le signal détecté. Nous présentons le descriptif de logiciels permettant de mieux appréhender le rôle des irrégularités de surface.The contribution of surface asperities to AES emission yields is discussed in terms of topography analysis. The methods allowing the distribution of heights, slopes, curvatures and other angular functions to be determined are presented here