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1.
M. Rubel J.P. Coad V. Philipps 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(4):711-717
First wall components in controlled fusion devices undergo severe modification by various physical and chemical processes arising from plasma-wall interactions: material erosion, its transport in the plasma and re-deposition. The intention of this work is to give a concise overview of key issues in the characterization of plasma-facing materials and components in tokamaks. The importance of surface analysis in studies of fuel inventory and material migration is presented. Experimental procedures and analysis methods are briefly reviewed with emphasis on ion beam techniques which play a prominent role in studies of wall components exposed to hot plasmas. Practical aspects in the analytical approach are addressed and special instrumentation used in these studies is described. 相似文献
2.
Lothar Philipps 《Artificial Intelligence and Law》1999,7(2-3):227-234
Since Aristotle it is recognised that a valid syllogism cannot have two particular premises. However, that is not how a lay person sees it; at least as long as the premises read many, most etc, instead of a plain some. The lay people are right if one considers that these syllogisms do not have strict but approximate (Zadeh) validity. Typically there are only particular premises available in everyday life and one is dependent on such syllogisms. – Some rules on the usage of particular premises are given below. 相似文献
3.
A. Litnovsky M. Laengner M. Matveeva Ch. Schulz L. Marot V.S. Voitsenya V. Philipps W. Biel U. Samm 《Fusion Engineering and Design》2011,86(9-11):1780-1783
Mirrors will be used in all optical and laser-based diagnostic systems of ITER. In the severe environment, the optical characteristics of mirrors will be degraded, hampering the entire performance of the respective diagnostics. A minute impurity deposition of 20 nm of carbon on the mirror is sufficient to decrease the mirror reflectivity by tens of percent outlining the necessity of the mirror cleaning in ITER. The results of R&D on plasma cleaning of molybdenum diagnostic mirrors are reported. The mirrors contaminated with amorphous carbon films in the laboratory conditions and in the tokamaks were cleaned in steady-state hydrogenic plasmas. The maximum cleaning efficiency of 4.2 nm/min was reached for the laboratory and soft tokamak hydrocarbon films, whereas for the hard tokamak films the carbidization of mirrors drastically decreased the cleaning efficiency down to 0.016 nm/min. This implies the necessity of sputtering cleaning of contaminated mirrors as the only reliable tool to remove the deposits by plasma cleaning. An overview of R&D program on mirror cleaning is provided along with plans for further studies and the recommendations for ITER mirror-based diagnostics. 相似文献
4.
Analysis of the residual neutral gas during plasma discharges in the tokamak TEXTOR shows considerable amounts of neutral CO and CO2. Details of these observations have suggested that the CO2 and part of the CO neutral gas is released from the surfaces by photon-stimulated desorption processes. To prove this suggestion additional mass-spectroscopic measurements have been performed in a chamber vacuum-sealed from the TEXTOR vacuum by a MgF2-window which is transparent for wavelengths above about 110 nm. It has been confirmed that CO2 and CO molecules together with H2 are released from the walls of the chamber by the photons penetrating from the TEXTOR plasma through the window. The overall desorption rate has been estimated to be between 10−4 and 10−5 molecules/photon and a linear relation between the amount of desorbed molecules and the total radiation from the plasma has been found. The results are discussed in view of the overall impurity release from the walls and limiters of TEXTOR. 相似文献
5.
A.G. Philipps S. Karuppanan C.M. Churchman D.A. Hills 《Engineering Fracture Mechanics》2008,75(18):5134-5139
Accurate calibrations are provided for the crack tip stress intensity factor for a crack of finite length emanating from the symmetric tip of a sharp notch, of arbitrary angle, in terms of the generalised stress intensity quantifying remote loading of the notch. The solution is applied to example problems and shown to be accurate for cases where the crack is much shorter then the notch depth. 相似文献
6.
Lothar Philipps 《Artificial Intelligence and Law》1993,2(1):51-63
The article investigates the interplay of moral rules in computer simulation. The investigation is based on two situations which are well-known to game theory: the prisoner's dilemma and the game of Chicken. The prisoner's dilemma can be taken to represent contractual situations, the game of Chicken represents a competitive situation on the one hand and the provision for a common good on the other. Unlike the rules usually used in game theory, each player knows the other's strategy. In that way, ever higher levels of reflection are reached reciprocally. Such strategies can be interpreted as moral rules.Artificial morality is related to the discipline of Artificial Life. As in artificial life, the use of genetic algorithms suggests itself. Rules of behaviour split and reunite as chromosome strings do. 相似文献
7.
Graham Beamson Adam J Papworth Charles Philipps Andrew M Smith Robin Whyman 《Advanced Synthesis \u0026amp; Catalysis》2010,352(5):869-883
Recyclable, heterogeneous bimetallic ruthenium/molybdenum catalysts, formed in situ from triruthenium dodecacarbonyl [Ru3(CO)12] and molybdenum hexacarbonyl [Mo(CO)6], are effective for the selective liquid phase hydrogenation of cyclohexylcarboxamide (CyCONH2) to cyclohexanemethylamine (CyCH2NH2), with no secondary or tertiary amine by‐product formation. Variation of Mo:Ru composition reveals both synergistic and poisoning effects, with the optimum combination of conversion and selectivity at ca. 0.5, and total inhibition of catalysis evident at ≥1. Good amide conversions are noted within the reaction condition regimes 20–100 bar hydrogen and 145–160 °C. The order of reactivity of these catalysts towards reduction of different amide functional groups is primary>tertiary≫secondary. In situ HP‐FT‐IR spectroscopy confirms that catalyst genesis occurs during an induction period associated with decomposition of the organometallic precursors. Ex situ characterisation, using XRD, XPS and EDX‐STEM, for active Mo:Ru compositions, has provided evidence for intimately mixed ca. 2.5–4 nm particles that contain metallic ruthenium, and molybdenum (in several oxidation states, including zero). 相似文献
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9.
CR Greenberg CL Taylor JC Haworth LE Seargeant S Philipps B Triggs-Raine BN Chodirker 《Canadian Metallurgical Quarterly》1993,17(1):215-217
Most drugs induce conditioned taste aversions and are therefore commonly supposed to produce nausea or sickness. Paradoxically, some drugs appear to lose induction capability when made to serve as a cue for a second drug that produces more severe sickness, perhaps through selective association with a hypothetical homeostatic or antisickness aftereffect of sickness. Using drug-drug pairings had made antisickness conditioning theory difficult to validate. We report here that rotation serves in lieu of a drug cue in rats. Rotation-drug pairings eliminate drug interactions and enable the sorts of parametric manipulations required to validate the theory. By postulating a common sickness mechanism to explain both taste aversion and aversion failure, the theory places the phenomenon within an adaptive evolutionary framework. Successful application could yield a direct countermeasure to severe nausea in clinical settings. 相似文献
10.
Cox's Proportional Hazards Model (PHM) has been widely applied in the analysis of lifetime data. The model is semi-parametric, so that weak assumptions are made about form of the hazard function. There have been medical developments of this model which have aided studies of repairable systems.A review of the practical use of this PHM model is given and particular attention is paid to the used of diagnostics statistics and graphs. Illustrations are given using field data from the semiconductor and electrical industries, and repairable data will be illustrated by data from the hydrocarbon industry. 相似文献