124,806 research outputs found
Balanced Colombeau products of the distributions and
No full textsummary:Results on singular products of the distributions and for natural are derived, when the products are balanced so that their sum exists in the distribution space. These results follow the pattern of a known distributional product published by Jan Mikusiński in 1966. The results are obtained in the Colombeau algebra of generalized functions, which is the most relevant algebraic construction for tackling nonlinear problems of Schwartz distributions
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Results on Colombeau product of distributions
No full textsummary:The differential -algebra \Cal G(\Bbb R^m) of generalized functions of J.-F. Colombeau contains the space \Cal D'(\Bbb R^m) of Schwartz distributions as a -vector subspace and has a notion of `association' that is a faithful generalization of the weak equality in \Cal D'(\Bbb R^m). This is particularly useful for evaluation of certain products of distributions, as they are embedded in \Cal G(\Bbb R^m), in terms of distributions again. In this paper we propose some results of that kind for the products of the widely used distributions and , with in , that have coinciding singular supports. These results, when restricted to dimension one, are also easily transformed into the setting of regularized model products in the classical distribution theory
Electrical activation of solid-phase epitaxially regrown ultra-low energy boron implants in Ge preamorphised silicon and SOI
No full textThe formation of highly activated ultra-shallow junctions (USJ) is one of the key requirements for the next generation of CMOS devices. One promising method for achieving this is the use of Ge preamorphising implants (PAI) prior to ultra-low energy B implantation. In future technology nodes, bulk silicon wafers may be supplanted by Silicon-on-Insulator (SOI), and an understanding of the Solid Phase Epitaxial (SPE) regrowth process and its correlation to dopant electrical activation in both bulk silicon and SOI is essential in order to understand the impact of this potential technology change. This kind of understanding will also enable tests of fundamental models for defect evolution and point-defect reactions at silicon/oxide interfaces. In the present work, B is implanted into Ge PAI silicon and SOI wafers with different PAI conditions and B doses, and resulting samples are annealed at various temperatures and times. Glancing-exit Rutherford Backscattering Spectrometry (RBS) is used to monitor the regrowth of the amorphous silicon, and the resulting redistribution and electrical activity of B are monitored by SIMS and Hall measurements. The results confirm the expected enhancement of regrowth velocity by B doping, and show that this velocity is otherwise independent of the substrate type and the Ge implant distribution within the amorphised layer. Hall measurements on isochronally annealed samples show that B deactivates less in SOI material than in bulk silicon, in cases where the Ge PAI end-of-range defects are close to the SOI back interface.</p
Manifold-valued generalized functions in full Colombeau spaces
No full textsummary:We introduce the notion of generalized function taking values in a smooth manifold into the setting of full Colombeau algebras. After deriving a number of characterization results we also introduce a corresponding concept of generalized vector bundle homomorphisms and, based on this, provide a definition of tangent map for such generalized functions
ALGEBRAIC AND GEOMETRIC THEORY OF THE TOPOLOGICAL RING OF COLOMBEAU GENERALIZED FUNCTIONS
No full textWe continue the investigation of the algebraic and topological structure of the algebra of Colombeau generalized functions with the aim of building up the algebraic basis for the theory of these functions. This was started in a previous work of Aragona and Juriaans, where the algebraic and topological structure of the Colombeau generalized numbers were studied. Here, among other important things, we determine completely the minimal primes of (K) over bar and introduce several invariants of the ideals of 9(Q). The main tools we use are the algebraic results obtained by Aragona and Juriaans and the theory of differential calculus on generalized manifolds developed by Aragona and co-workers. The main achievement of the differential calculus is that all classical objects, such as distributions, become Cl-functions. Our purpose is to build an independent and intrinsic theory for Colombeau generalized functions and place them in a wider context
Results on generalized models and singular products of distributions in the Colombeau algebra
No full textsummary:Models of singularities given by discontinuous functions or distributions by means of generalized functions of Colombeau have proved useful in many problems posed by physical phenomena. In this paper, we introduce in a systematic way generalized functions that model singularities given by distributions with singular point support. Furthermore, we evaluate various products of such generalized models when the results admit associated distributions. The obtained results follow the idea of a well-known result of Jan Mikusiński on balancing of singular distributional products
On the sign of Colombeau functions and applications to conservation laws
No full textsummary:A generalized concept of sign is introduced in the context of Colombeau algebras. It extends the sign of the point-value in the case of sufficiently regular functions. This concept of generalized sign is then used to characterize the entropy condition for discontinuous solutions of scalar conservation laws
Understanding the role of buried Si/SiO2 interface on dopant and defect evolution in PAI USJ
No full textFor CMOS technology, generations beyond the 65 nm node a major goal is achieving highly activated, ultra-shallow and abrupt profiles. In the case of p-type (boron) implants, one method to achieve this is using Ge preamorphization (PAI) prior to ultra-low energy B implantation. However, for future technology nodes, new issues arise when bulk silicon is supplanted by silicon-on-insulator (SOI). Understanding the strong impact of the buried Si/SiO2 interface, will enable tests of fundamental models on defect evolution, electrical activation and diffusion. In the present study, boron has been implanted in germanium-preamorphized silicon and SOI wafers. Subsequent to implantation, an isochronal and isothermal annealing study of the samples was carried out. Electrical and structural properties were measured by Hall effect and SIMS techniques. The results show a range of effects in both substrate types, including TED and deactivation driven by interstitials from the end-of-range (EOR) defects. However, in the SOI material there is a lower boron deactivation and the EOR defects are eliminated at a lower thermal budget in SOI than in the bulk silicon due to competition between the upper SOI interface and the Si surface which both act as sinks for interstitials.</p
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