140,530 research outputs found
Epitaxial growth of rhombohedral v- and cubic g-CuI
No full textArt. 126218Isolated small crystals and closed epitaxial layers of CuI could be deposited on various substrates by close distance sublimation (CDS). X-ray diffraction measurements and detailed TEM studies revealed phase pure cubic g-CuI (zincblende structure) layers and a combination of a CuI multilayer structure with g-CuI. The multilayer structure, a 12R polytype with the space group R3m, the lattice parameters a0 = 0.4279 nm, c0 = 4.25 nm, and a twelve layers array consisting of wurtzite-like and zincblende layer sequences in combination with g-CuI could be detected. The presence of the polytype phase was detected always together with g-CuI. The epitaxial relationships between the CuI phases and various substrates are discussed. Low temperature (2 K) photoluminescence spectra of phase-pure g-CuI layers show typical excitonic emission spectra in the range between 3.0 and 3.1 eV. Samples containing both, the 12R polytype and g-CuI, additionally reveal a predominant series of intense emission lines around 3.25 eV attributed to excitonic emission from the rhombohedral phase.57
A study on the reliability of consecutive k-Out-of-n: G systems based on Copula
No full textThe computation of reliability characteristics of a system that consists of dependent components is sometimes difficult especially when the type of dependence is not known. This article introduces the copula method to calculate the reliability of dependent consecutive k-out-of-n: G systems. The components in these systems are dependent on each other and the dependency may be either linear or nonlinear. The copula is a popular tool for modeling the dependence structure of data. It contains the information about the dependency structure of a vector of random variables and can capture nonlinear dependence. Based on the copula theory, the article analyzes the consecutive k-out-of-n: G systems and gets the reliability indexes. Finally, some numerical examples are presented to illustrate the results obtained in this article.Peer reviewe
Amplified detection of nucleic acid by G-quadruplex based hybridization chain reaction
No full textA protein-free, isothermal, self-amplified nucleic acid sensing system which was a G-quadruplex integrated hybridization chain reaction (GQ-HCR) system was developed. The G-quadruplex was closed two-thirds in the loop and one-third in the stem of one of the GQ-HCR hairpin probes. In the absence of the target molecule, the GQ-HCR probes stayed as inactive meta-stable hairpin structures and the G-quadruplex was inert. Reversely, the GQ-HCR probes could be cross-opened to start a hybridization chain reaction and the closed G-quadruplex could be released to be free when the GQ-HCR probes came across the target molecule. The GQ-HCR nucleic acid sensing system could detect as low as 7.5 nM ssDNA or RNA by the colorimetric method and 4 nM ssDNA by the fluorometric method. Less than 10 copies of dsDNA template could also be detected when PCR was combined with the GQ-HCR system (PCR+GQ-HCR). Because of these advantages, the GQ-HCR system was also studied for application in visual chip detection to obtain a satisfactory repeatable and specific result. (c) 2012 Elsevier B.V. All rights reserved
Admix'em: A flexible framework for forward-time simulations of hybrid populations with selection and mate choice
No full textSummary: We introduce a new forward-time simulator, Admix'em, that allows for rapid and realistic simulations of admixed populations with selection. Complex selection can be achieved through user-defined fitness and mating-preference probability functions. Users can specify realistic genomic landscapes and model neutral SNPs in addition to sites under selection. Admix'em is designed to simulate selection in admixed populations but can also be used as a general population simulator. Usage and examples are in the supplement. Availability and Implementation: C ++ and OpenMP, supports 64-bit Linux/Unix-like platforms. https://github.com/melop/admixem
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
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
Recommended from our members
3346: Samuel G. Freedman, author, 2013
No full textPhotograph of author Samuel G. Freedman, at NT Daily Slash meeting in the Mayborn School of Journalism at UNT
Optical particle detection integrated in a dielectrophoretic lab-on-a-chip
No full textThe design and fabrication of a dielectrophoretic "lab-on-a-chip" device for bioparticle processing and counting is presented. The device consists of a multi-layer travelling wave dielectrophoretic electrode array for manipulating particles and/or fluids, micro channels for delivering samples, and optical fibres for counting particles and/or measuring their velocities. Single particles were detected optically using either light scattering or fluorescence emission. The technology described in this work is potentially applicable to a range of particulate diagnostic systems
Light-Weight Free-Standing Carbon Nanotube-Silicon Films for Anodes of Lithium Ion Batteries
No full textSilicon is an attractive alloy-type anode material because of its highest known capacity (4200 mAh/g). However, lithium insertion into and extraction from silicon are accompanied by a huge volume change, up to 300%, which induces a strong strain on silicon and causes pulverization and rapid capacity fading due to the loss of the electrical contact between part of silicon and current collector. Si nanostructures such as nanowires, which are chemically and electrically bonded to the current collector, can overcome the pulverization problem, however, the heavy metal current collectors in these systems are larger in weight than Si active material. Herein we report a novel anode structure free of heavy metal current collectors by integrating a flexible, conductive carbon nanotube (CNT) network into a Si anode. The composite film is free-standing and has a structure similar to the steel bar reinforced concrete, where the infiltrated CNT network functions as both mechanical support and electrical conductor and Si as a high capacity anode material for Li-ion battery. Such free-standing film has a low sheet resistance of similar to 30 Ohm/sq. It shows a high specific charge storage capacity (similar to 2000 mAh/g) and a good cycling life, superior to pure sputtered-on silicon films with similar thicknesses. Scanning electron micrographs show that Si is still connected by the CNT network even when small breaking or cracks appear in the film after cycling. The film can also "ripple up" to release the strain of a large volume change during lithium intercalation. The conductive composite film can function as both anode active material and current collector. It offers similar to 10 times improvement in specific capacity compared with widely used graphite/copper anode sheets.Y
- …
