8,694 research outputs found
Intercalation of graphene on SiC(0001) via ion-implantation
Electronic devices based on graphene technology are catching on rapidly and
the ability to engineer graphene properties at the nanoscale is becoming, more
than ever, indispensable. Here, we present a new procedure of graphene
functionalization on SiC(0001) that paves the way towards the fabrication of
complex graphene electronic chips. The procedure resides on the well-known
ion-implantation technique. The efficiency of the working principle is
demonstrated by the intercalation of the epitaxial graphene layer on SiC(0001)
with Bi atoms, which was not possible following standard procedures. Our
results put forward the ion-beam lithography to nanostructure and functionalize
desired graphene chips
Continuous Reasoning for Managing Next-Gen Distributed Applications.
Continuous reasoning has proven effective in incrementally analysing changes in application codebases within Continuous Integration/Continuous Deployment (CI/CD) software release pipelines. In this article, we present a novel declarative continuous reasoning approach to support the management of multi-service applications over the Cloud-IoT continuum, in particular when infrastructure variations impede meeting application's hardware, software, IoT or network QoS requirements. We show how such an approach brings considerable speed-ups compared to non-incremental reasoning
Combined observations of meteors by image-orthicon television camera and multi-station radar
Observations from multiple sites of a radar network and by television of 29 individual meteors from February 1969 through June 1970 are reported. Only 12 of the meteors did not appear to fragment over all the observed portion of their trajectories. From these 12, the relation for the radar magnitude to the panchromatic absolute magnitude was found in terms of velocity of the meteor. A very tentative fit to the data on the duration of long enduring echoes versus visual absolute magnitude is made. The exponential decay characteristics of the later parts of several of the light curves are pointed out as possible evidence of mutual coalescence of droplets into which the meteoroid has completely broken
Asymptotic stability of the Cauchy and Jensen functional equations
The aim of this note is to investigate the asymptotic stability behaviour of
the Cauchy and Jensen functional equations. Our main results show that if these
equations hold for large arguments with small error, then they are also valid
everywhere with a new error term which is a constant multiple of the original
error term. As consequences, we also obtain results of hyperstability character
for these two functional equations
Quasi-selective ultrafilters and asymptotic numerosities
We isolate a new class of ultrafilters on N, called “quasi-selective” because they are intermediate between selective ultrafilters and P-points. (Under the Continuum Hypothesis these three classes are distinct.) The existence of quasi-selective ultrafilters is equivalent to the existence of “asymptotic numerosities” for all sets of tuples A ⊆ N^k. Such numerosities are hypernatural numbers that generalize finite cardinalities to countable point sets. Most notably, they maintain the structure of ordered semiring, and, in a precise sense, they allow for a natural extension of asymptotic density to all sets of tuples of natural numbers
Devices based on 2D materials for on-chip amplification of ionization charges
Pixels detectors are widely used ionizing radiation detection devices in high-energy physics (HEP)experiments. Segmented detectors have been employed for many years due to the need to simul-taneously track the thousands of particles emerging from modern colliders. For more preciseand accurate measurements one would like to have faster, less noisy and smaller pixels, but cur-rent technology imposes several limits on these characteristics. The aim of this work is to ex-plore the possible applications of bi-dimensional materials such as Graphene or transition metaldichalcogenide monolayers (TMDs) to address these problems. In particular, one wants to de-termine whether nano-electronic devices based on 2D materials could be used to obtain built-inpre-amplification of the pixel signal, thus achieving better detection performance. The workingprinciple is the field-effect modulation of the channel conductivity in a 2D material-based tran-sistor, due to the presence of ionization charges in a silicon absorber. Several architectures aretested, and a final device of choice is presented, with a sketch of a realistic readout system andits noise figure. The conductance modulation due to incoming particles is found to be more than30%, resulting in a strong current signal, which leads to very favourable signal-to-noise ratios (SNR)
Direct evidence for efficient ultrafast charge separation in epitaxial WS/graphene heterostructure
We use time- and angle-resolved photoemission spectroscopy (tr-ARPES) to
investigate ultrafast charge transfer in an epitaxial heterostructure made of
monolayer WS and graphene. This heterostructure combines the benefits of a
direct gap semiconductor with strong spin-orbit coupling and strong
light-matter interaction with those of a semimetal hosting massless carriers
with extremely high mobility and long spin lifetimes. We find that, after
photoexcitation at resonance to the A-exciton in WS, the photoexcited holes
rapidly transfer into the graphene layer while the photoexcited electrons
remain in the WS layer. The resulting charge transfer state is found to
have a lifetime of \,ps. We attribute our findings to differences in
scattering phase space caused by the relative alignment of WS and graphene
bands as revealed by high resolution ARPES. In combination with spin-selective
excitation using circularly polarized light the investigated WS/graphene
heterostructure might provide a new platform for efficient optical spin
injection into graphene.Comment: 28 pages, 14 figure
A defective ABC transporter of the MRP family, responsible for the bean lpa1 mutation, affects the regulation of the phytic acid pathway, reduces seed myo-inositol and alters ABA sensitivity
We previously identified the lpa1 (low phytic acid) 280-10 line that carries a mutation conferring a 90% reduction in phytic acid (InsP6) content. In contrast to other lpa mutants, lpa1(280-10) does not display negative pleiotropic effects. In the present paper, we have identified the mutated gene and analysed its impact on the phytic acid pathway. Here, we mapped the lpa1(280-10) mutation by bulk analysis on a segregating F2 population, an then, by comparison with the soybean genome, we identified and sequenced a candidate gene. The InsP6 pathway was analysed by gene expression and quantification of metabolites. The mutated Pvmrp1(280-10) cosegregates with the lpa1(280-10) mutation, and the expression level of several genes of the InsP6 pathway are reduced in the lpa1(280-10) mutant as well as the inositol and raffinosaccharide content. PvMrp2, a very similar paralogue of PvMrp1 was also mapped and sequenced. The lpa1 mutation in beans is likely the result of a defective Mrp1 gene (orthologous to the lpa genes AtMRP5 and ZmMRP4), while its Mrp2 paralog is not able to complement the mutant phenotype in the seed. This mutation appears to down-regulate the InsP6 pathway at the transcriptional level, as well as altering inositol-related metabolism and affecting ABA sensitivity
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