2,898 research outputs found
Designing all-graphene nanojunctions by covalent functionalization
We investigated theoretically the effect of covalent edge functionalization,
with organic functional groups, on the electronic properties of graphene
nanostructures and nano-junctions. Our analysis shows that functionalization
can be designed to tune electron affinities and ionization potentials of
graphene flakes, and to control the energy alignment of frontier orbitals in
nanometer-wide graphene junctions. The stability of the proposed mechanism is
discussed with respect to the functional groups, their number as well as the
width of graphene nanostructures. The results of our work indicate that
different level alignments can be obtained and engineered in order to realize
stable all-graphene nanodevices
Quantum Monte Carlo Evidence for d-wave Pairing in the 2D Hubbard Model at a van Hove Singularity
We implement a Quantum Monte Carlo calculation for a repulsive Hubbard model
with nearest and next-nearest neighbor hopping interactions on clusters up to
12x12. A parameter region where the Fermi level lies close to the van Hove
singularity at the Saddle Points in the bulk band structure is investigated. A
pairing tendency in the symmetry channel, but no other channel,
is found. Estimates of the effective pairing interaction show that it is close
to the value required for a 40 K superconductor. Finite-size scaling compares
with the attractive Hubbard model.Comment: 11 pages, REVTex, 4 figures, postscrip
Hall effect of charge carriers in a correlated system
The dynamical Hall response in a correlated electronic system is analysed
within the linear response theory for tight binding models. At the d.c.
Hall constant for a single quasiparticle is expressed explicitly via the charge
stiffness, and a semiclassical result is recovered. As expected a hole-like
response is found for the mobile hole introduced into a quantum
antiferromagnet, as represented by the model.Comment: 4 pages, RevTeX, no figure
Synthesizing efficacious genistein in conjugation with superparamagnetic Fe<sub>3</sub>O<sub>4</sub> decorated with bio-compatible carboxymethylated chitosan against acute leukemia lymphoma
Micro-manufacturing : research, technology outcomes and development issues
Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing
Phugoid motion for grazing-entry trajectories at near-circular speeds
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77023/1/AIAA-26742-801.pd
Optical properties and charge-transfer excitations in edge-functionalized all-graphene nanojunctions
We investigate the optical properties of edge-functionalized graphene
nanosystems, focusing on the formation of junctions and charge transfer
excitons. We consider a class of graphene structures which combine the main
electronic features of graphene with the wide tunability of large polycyclic
aromatic hydrocarbons. By investigating prototypical ribbon-like systems, we
show that, upon convenient choice of functional groups, low energy excitations
with remarkable charge transfer character and large oscillator strength are
obtained. These properties can be further modulated through an appropriate
width variation, thus spanning a wide range in the low-energy region of the
UV-Vis spectra. Our results are relevant in view of designing all-graphene
optoelectronic nanodevices, which take advantage of the versatility of
molecular functionalization, together with the stability and the electronic
properties of graphene nanostructures.Comment: J. Phys. Chem. Lett. (2011), in pres
New measurement of via neutron capture on hydrogen at Daya Bay
This article reports an improved independent measurement of neutrino mixing
angle at the Daya Bay Reactor Neutrino Experiment. Electron
antineutrinos were identified by inverse -decays with the emitted
neutron captured by hydrogen, yielding a data-set with principally distinct
uncertainties from that with neutrons captured by gadolinium. With the final
two of eight antineutrino detectors installed, this study used 621 days of data
including the previously reported 217-day data set with six detectors. The
dominant statistical uncertainty was reduced by 49%. Intensive studies of the
cosmogenic muon-induced Li and fast neutron backgrounds and the
neutron-capture energy selection efficiency, resulted in a reduction of the
systematic uncertainty by 26%. The deficit in the detected number of
antineutrinos at the far detectors relative to the expected number based on the
near detectors yielded in the
three-neutrino-oscillation framework. The combination of this result with the
gadolinium-capture result is also reported.Comment: 26 pages, 23 figure
The South Asian genome
Genetics of disease
Microarrays
Variant genotypes
Population genetics
Sequence alignment
AllelesThe genetic sequence variation of people from the Indian subcontinent who comprise one-quarter of the world's population, is not well described. We carried out whole genome sequencing of 168 South Asians, along with whole-exome sequencing of 147 South Asians to provide deeper characterisation of coding regions. We identify 12,962,155 autosomal sequence variants, including 2,946,861 new SNPs and 312,738 novel indels. This catalogue of SNPs and indels amongst South Asians provides the first comprehensive map of genetic variation in this major human population, and reveals evidence for selective pressures on genes involved in skin biology, metabolism, infection and immunity. Our results will accelerate the search for the genetic variants underlying susceptibility to disorders such as type-2 diabetes and cardiovascular disease which are highly prevalent amongst South Asians.Whole genome sequencing to discover genetic variants underlying type-2 diabetes, coronary heart disease and related phenotypes amongst Indian Asians. Imperial College Healthcare NHS Trust cBRC 2011-13 (JS Kooner [PI], JC Chambers)
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