1,056 research outputs found
Suppressing nano-scale stick-slip motion by feedback
When a micro cantilever with a nano-scale tip is manipulated on a substrate
with atomic-scale roughness, the periodic lateral frictional force and
stochastic fluctuations may induce stick-slip motion of the cantilever tip,
which greatly decreases the precision of the nano manipulation. This unwanted
motion cannot be reduced by open-loop control especially when there exist
parameter uncertainties in the system model, and thus needs to introduce
feedback control. However, real-time feedback cannot be realized by the
existing virtual reality virtual feedback techniques based on the position
sensing capacity of the atomic force microscopy (AFM). To solve this problem,
we propose a new method to design real-time feedback control based on the force
sensing approach to compensate for the disturbances and thus reduce the
stick-slip motion of the cantilever tip. Theoretical analysis and numerical
simulations show that the controlled motion of the cantilever tip tracks the
desired trajectory with much higher precision. Further investigation shows that
our proposal is robust under various parameter uncertainties. Our study opens
up new perspectives of real-time nano manipulation.Comment: 8 pages, 10 figure
Quantum broadcast communication
Broadcast encryption allows the sender to securely distribute his/her secret
to a dynamically changing group of users over a broadcast channel. In this
paper, we just consider a simple broadcast communication task in quantum
scenario, which the central party broadcasts his secret to multi-receiver via
quantum channel. We present three quantum broadcast communication schemes. The
first scheme utilizes entanglement swapping and Greenberger-Horne-Zeilinger
state to realize a task that the central party broadcasts his secret to a group
of receivers who share a group key with him. In the second scheme, based on
dense coding, the central party broadcasts the secret to multi-receiver who
share each of their authentication key with him. The third scheme is a quantum
broadcast communication scheme with quantum encryption, which the central party
can broadcast the secret to any subset of the legal receivers
The role of 245 phase in alkaline iron selenide superconductors revealed by high pressure studies
Here we show that a pressure of about 8 GPa suppresses both the vacancy order
and the insulating phase, and a further increase of the pressure to about 18
GPa induces a second transition or crossover. No superconductivity has been
found in compressed insulating 245 phase. The metallic phase in the
intermediate pressure range has a distinct behavior in the transport property,
which is also observed in the superconducting sample. We interpret this
intermediate metal as an orbital selective Mott phase (OSMP). Our results
suggest that the OSMP provides the physical pathway connecting the insulating
and superconducting phases of these iron selenide materials.Comment: 32 pages, 4 figure
Pseuduscalar Heavy Quarkonium Decays With Both Relativistic and QCD Radiative Corrections
We estimate the decay rates of ,
, and ,
, by taking into account both relativistic and
QCD radiative corrections. The decay amplitudes are derived in the
Bethe-Salpeter formalism. The Bethe-Salpeter equation with a QCD-inspired
interquark potential are used to calculate the wave functions and decay widths
for these states. We find that the relativistic correction to the
ratio is negative and tends to compensate the positive contribution from
the QCD radiative correction. Our estimate gives and ,
which are smaller than their nonrelativistic values. The hadronic widths
and are then indicated accordingly to the first order
QCD radiative correction, if . The decay widths for
states are also estimated. We show that when making the assmption
that the quarks are on their mass shells our expressions for the decay widths
will become identical with that in the NRQCD theory to the next to leading
order of and .Comment: 14 pages LaTex (2 figures included
Multiparty simultaneous quantum identity authentication based on entanglement swapping
We present a multiparty simultaneous quantum identity authentication protocol
based on entanglement swapping. In our protocol, the multi-user can be
authenticated by a trusted third party simultaneously
Shortâ term and longâ term impacts of Helicobacter pylori eradication with reverse hybrid therapy on the gut microbiota
Background and AimsAntiâ Helicobacter pylori therapy may lead to the growth of pathogenic or antibioticâ resistant bacteria in the gut. The study aimed to investigate the shortâ term and longâ term impacts of H.Ă pylori eradication with reverse hybrid therapy on the components and macrolide resistance of the gut microbiota.MethodsHelicobacter pyloriâ related gastritis patients were administered a 14â day reverse hybrid therapy. Fecal samples were collected before treatment and at the end of week 2, week 8, and week 48. The V3â V4 region of the bacterial 16S rRNA gene in fecal specimens was amplified by polymerase chain reaction and sequenced on Illumina MiSeq platform. Additionally, amplification of erm(B) gene (encoding erythromycin resistance methylase) was performed.ResultsReverse hybrid therapy resulted in decreased relative abundances of Firmicutes (from 62.0% to 30.7%; PĂ <Ă 0.001) and Actinobacteria (from 3.4% to 0.6%; 0.032) at the end of therapy. In contrast, the relative abundance of Proteobacteria increased from 10.2% to 49.1% (0.002). These microbiota alterations did not persist but returned to the initial levels at week 8 and week 48. The amount of erm(B) gene in fecal specimens was comparable with the pretreatment level at week 2 but increased at week 8 (0.025) and then returned to the pretreatment level by week 48.ConclusionsHelicobacter pylori eradication with reverse hybrid therapy can lead to shortâ term gut dysbiosis. The amount of erm(B) gene in the stool increased transiently after treatment and returned to the pretreatment level at 1â year postâ treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152555/1/jgh14736_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152555/2/jgh14736.pd
Phase Diagram of Pressure-induced Superconductivity and its Relation to Hall Coefficient in Bi2Te3 Single Crystal
Pressure-induced superconductivity and its relation to corresponding Hall
coefficient (RH) have been reported for Bi2Te3, one of known topological
insulators. A full phase diagram is presented which shows a complex dependence
of the superconducting transition temperature as a function of pressure over an
extensive range. High-pressure RH measurements reveal a close relation of these
complex behaviors, particularly, a dramatic change of dRH/dP before structural
phase transition and a pressure-induced crossover on RH in the high pressure
phase were observed.Comment: 14 pages and 3 figure
Consistent as-similar-as-possible non-isometric surface registration
Š 2017 The Author(s)Non-isometric surface registration, aiming to align two surfaces with different sizes and details, has been widely used in computer animation industry. Various existing surface registration approaches have been proposed for accurate template fitting; nevertheless, two challenges remain. One is how to avoid the mesh distortion and fold over of surfaces during transformation. The other is how to reduce the amount of landmarks that have to be specified manually. To tackle these challenges simultaneously, we propose a consistent as-similar-as-possible (CASAP) surface registration approach. With a novel defined energy, it not only achieves the consistent discretization for the surfaces to produce accurate result, but also requires a small number of landmarks with little user effort only. Besides, CASAP is constrained as-similar-as-possible so that angles of triangle meshes are preserved and local scales are allowed to change. Extensive experimental results have demonstrated the effectiveness of CASAP in comparison with the state-of-the-art approaches
Equivalent efficacies of reverse hybrid and concomitant therapies in first- line treatment of Helicobacter pylori infection
Background and AimConcomitant therapy is a recommended first- line treatment for Helicobacter pylori infection in most national or international consensuses. Reverse hybrid therapy is a modified 14- day concomitant therapy without clarithromycin and metronidazole in the final 7ĂÂ days. This study aims to test whether 14- day reverse hybrid therapy is non- inferior to 14- day concomitant therapy in the first- line treatment of H.ĂÂ pylori infection.MethodsHelicobacter pylori- infected adult patients were randomly assigned to receive either reverse hybrid therapy (dexlansoprazole 60ĂÂ mg o.d. plus amoxicillin 1ĂÂ g b.d. for 14ĂÂ days, and clarithromycin 500ĂÂ mg plus metronidazole 500ĂÂ mg b.d. for initial 7ĂÂ days) or concomitant therapy (dexlansoprazole 60ĂÂ mg once o.d. plus amoxicillin 1ĂÂ g, clarithromycin 500ĂÂ mg, and metronidazole 500ĂÂ mg b.d. for 14ĂÂ days). H.ĂÂ pylori status was assessed 6ĂÂ weeks after the end of treatment.ResultsHelicobacter pylori- infected participants (nĂÂ =ĂÂ 248) were randomized to receive either 14- day reverse hybrid therapy (nĂÂ =ĂÂ 124) or 14- day concomitant therapy (nĂÂ =ĂÂ 124). Intention- to- treat analysis demonstrated that the two therapies had comparable eradication rate (95.2% vs 93.5%; 95% confidence interval, - 4.0% to 7.4%; PĂÂ =ĂÂ 0.582). However, reverse hybrid therapy had a much lower frequency of adverse events than concomitant therapy (20.2% vs 38.7%, PĂÂ =ĂÂ 0.001). The two therapies exhibited comparable drug adherence (93.5% vs 87.9%, PĂÂ =ĂÂ 0.125).ConclusionsFourteen- day reverse hybrid therapy and 14- day concomitant therapy are equivalent in efficacy for the first- line treatment of H.ĂÂ pylori infection. However, reverse hybrid therapy has fewer adverse events compared with concomitant therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163472/2/jgh15034_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163472/1/jgh15034.pd
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