4,712 research outputs found
The Fourth Element: Characteristics, Modelling, and Electromagnetic Theory of the Memristor
In 2008, researchers at HP Labs published a paper in {\it Nature} reporting
the realisation of a new basic circuit element that completes the missing link
between charge and flux-linkage, which was postulated by Leon Chua in 1971. The
HP memristor is based on a nanometer scale TiO thin-film, containing a
doped region and an undoped region. Further to proposed applications of
memristors in artificial biological systems and nonvolatile RAM (NVRAM), they
also enable reconfigurable nanoelectronics. Moreover, memristors provide new
paradigms in application specific integrated circuits (ASICs) and field
programmable gate arrays (FPGAs). A significant reduction in area with an
unprecedented memory capacity and device density are the potential advantages
of memristors for Integrated Circuits (ICs). This work reviews the memristor
and provides mathematical and SPICE models for memristors. Insight into the
memristor device is given via recalling the quasi-static expansion of Maxwell's
equations. We also review Chua's arguments based on electromagnetic theory.Comment: 28 pages, 14 figures, Accepted as a regular paper - the Proceedings
of Royal Society
Metallic nanoparticles and nanostructures for bio-applications
This paper elaborates on approaches of synthesis of Au and Ag nanoparticles (NPs), deposition of colloid onto glass substrate and encapsulation of NPs with silicon dioxide (SiO2) thin shell. As one important bio application of metallic nanoparticles, both solution-based and substrate-based fluorescence enhancement tests are demonstrated
Comprehensive Chemical Characterisation of Durio zibethinus
This study investigated the chemical properties of Durio zibethinus (Durian) in Malaysia. The cultivars included in the present study were D101, D197, and Kampung. A wide range of chemical properties such as proximate nutritional content, minerals, total phenolic content was analysed using established analytical methods. The antioxidant capacity in term of free radical scavenging activity was determined using colorimetric assay, whereas metabolite profiles of samples were analysed by hyphenated high throughput tool like GC-MS. The results showed that D197 durian had the highest content of ash, protein, fat, and carbohydrate, but the lowest moisture level. Potassium was found to be the highest mineral (8.68–11.36 mg g–1), followed by sodium (3.2–7.6 mg g–1), magnesium (0.86–1.88 mg g–1), and calcium (2.74–3.80 mg g–1) in the tested cultivars. The major sulphur containing compounds (% relative peak area) such as hydrogen sulphide (5.0–8.3%), methanethiol (0.5–1.0%), ethanethiol (20.7–35.0%), 1-propanethiol (2.7– 9.5%), and diethyl disulphide (0.6–1.9%), and esters, especially ethyl 2-methylbutanoate (10.0–15.0%), methyl 2-methylbutanoate (1.0%), and propyl 2-methylbutanoate (1.5%) were detected when fresh samples were heated in headspace GC-MS. However, those compounds evaporated during ultrasound assisted extraction and oven drying even at 40 °C
Structural Characterization of Rapid Thermal Oxidized Si\u3csub\u3e1−x−y\u3c/sub\u3eGe\u3csub\u3ex\u3c/sub\u3eC\u3csub\u3ey\u3c/sub\u3e Alloy Films Grown by Rapid Thermal Chemical Vapor Deposition
The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that the oxidized films closely resemble to Si1−xGex films. For tensile films, two broad regions, one with carbon content higher and the other lower than that required for full strain compensation, coexist in the oxidized films
Implications of Recent Measurements
The recent measurements of the color-suppressed modes imply non-vanishing relative final-state interaction (FSI)
phases among various decay amplitudes. Depending on whether or
not FSIs are implemented in the topological quark-diagram amplitudes, two
solutions for the parameters and are extracted from data using
various form-factor models. It is found that is not universal:
and with a relative phase
of order between and . If FSIs are not included in
quark-diagram amplitudes from the outset, and
will become smaller. The large value of compared to
or naive expectation implies the importance of
long-distance FSI contributions to color-suppressed internal -emission via
final-state rescatterings of the color-allowed tree amplitude.Comment: 17 pages. The Introduction is substantially revised and the order of
the presentation in Sec. 2 is rearranged. To appear in Phys. Re
Low-Mass Baryon-Antibaryon Enhancements in B Decays
The nature of low-mass baryon-antibaryon enhancements seen in B decays is
explored. Three possibilities include (i) states near threshold as found in a
model by Nambu and Jona-Lasinio, (ii) isoscalar states with coupled to a pair of gluons, and (iii) low-mass enhancements favored by the
fragmentation process. Ways of distinguishing these mechanisms using angular
distributions and flavor symmetry are proposed.Comment: 8 pages, LaTeX, no figures, to be submitted to Phys. Rev. D. One
reference adde
Puzzles in physics
I discuss some puzzles observed in exclusive meson decays, concentrating
on the large difference between the direct CP asymmetries in the and modes, the large
branching ratio, and the large deviation of the mixing-induced CP asymmetries
in the penguins from those in the trees.Comment: 6 pages, 1 figure, talk presented at the 9th Workshop on High Energy
Physics Phenomenology, Bhubaneswar, Orissa, India, Jan. 3-14, 2006; reference
adde
Imaging Oxygen Defects and their Motion at a Manganite Surface
Manganites are technologically important materials, used widely as solid
oxide fuel cell cathodes: they have also been shown to exhibit
electroresistance. Oxygen bulk diffusion and surface exchange processes are
critical for catalytic action, and numerous studies of manganites have linked
electroresistance to electrochemical oxygen migration. Direct imaging of
individual oxygen defects is needed to underpin understanding of these
important processes. It is not currently possible to collect the required
images in the bulk, but scanning tunnelling microscopy could provide such data
for surfaces. Here we show the first atomic resolution images of oxygen defects
at a manganite surface. Our experiments also reveal defect dynamics, including
oxygen adatom migration, vacancy-adatom recombination and adatom bistability.
Beyond providing an experimental basis for testing models describing the
microscopics of oxygen migration at transition metal oxide interfaces, our work
resolves the long-standing puzzle of why scanning tunnelling microscopy is more
challenging for layered manganites than for cuprates.Comment: 7 figure
Strong duality in conic linear programming: facial reduction and extended duals
The facial reduction algorithm of Borwein and Wolkowicz and the extended dual
of Ramana provide a strong dual for the conic linear program in the absence of any constraint qualification. The facial
reduction algorithm solves a sequence of auxiliary optimization problems to
obtain such a dual. Ramana's dual is applicable when (P) is a semidefinite
program (SDP) and is an explicit SDP itself. Ramana, Tuncel, and Wolkowicz
showed that these approaches are closely related; in particular, they proved
the correctness of Ramana's dual using certificates from a facial reduction
algorithm.
Here we give a clear and self-contained exposition of facial reduction, of
extended duals, and generalize Ramana's dual:
-- we state a simple facial reduction algorithm and prove its correctness;
and
-- building on this algorithm we construct a family of extended duals when
is a {\em nice} cone. This class of cones includes the semidefinite cone
and other important cones.Comment: A previous version of this paper appeared as "A simple derivation of
a facial reduction algorithm and extended dual systems", technical report,
Columbia University, 2000, available from
http://www.unc.edu/~pataki/papers/fr.pdf Jonfest, a conference in honor of
Jonathan Borwein's 60th birthday, 201
Phenomenological Consequences of Right-handed Down Squark Mixings
The mixings of quarks, hidden from view in Standard Model (SM), are
naturally the largest if one has an Abelian flavor symmetry. With supersymmetry
(SUSY) their effects can surface via squark loops. Squark and
gluino masses are at TeV scale, but they can still induce effects comparable to
SM in (or ) mixings, while mixing could be close to recent
hints from data. In general, CP phases would be different from SM, as may be
indicated by recent B Factory data. Presence of non-standard soft SUSY
breakings with large could enhance (or )
transitions.Comment: Version to appear in Phys. Rev. Let
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