2,522 research outputs found
Non-extensivity of the QCD pT spectra
We try to establish a connection between the hadronic distributions, in
proton-proton collisions at very high transverse momentum ,
obtained via perturbative QCD and the Tsallis non extensive statistics. Our
motivation is that while the former is expected to be valid at extremely high
momentum, due to asymptotic freedom, the latter has been very successful in
describing experimental spectra over a wide range of momentum. Matching the non
extensive statistics with the asymptotic behaviour expected
from QCD leads to the value of .Comment: 4 page
Insights into the Fallback Path of Best-Effort Hardware Transactional Memory Systems
DOI 10.1007/978-3-319-43659-3Current industry proposals for Hardware Transactional Memory (HTM) focus on best-effort solutions (BE-HTM) where hardware limits are imposed on transactions. These designs may show a significant performance degradation due
to high contention scenarios and different hardware and operating system limitations that abort transactions, e.g. cache overflows, hardware and software exceptions, etc. To deal with these events and to ensure forward progress, BE-HTM systems usually provide a software fallback path to execute a lock-based version of the code.
In this paper, we propose a hardware implementation of an irrevocability mechanism as an alternative to the software fallback path to gain insight into the hardware improvements that could enhance the execution of such a fallback. Our mechanism anticipates the abort that causes the transaction serialization, and stalls other transactions in the system so that transactional work loss is mini-
mized. In addition, we evaluate the main software fallback path approaches and propose the use of ticket locks that hold precise information of the number of transactions waiting to enter the fallback. Thus, the separation of transactional
and fallback execution can be achieved in a precise manner. The evaluation is carried out using the Simics/GEMS simulator and the complete range of STAMP transactional suite benchmarks. We obtain significant performance benefits of around twice the speedup and an abort reduction of 50% over the software fallback path for a number of benchmarks.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The Lower Estimate for Bernstein Operator
MSC 2010: 41A10, 41A15, 41A25, 41A36For functions belonging to the classes C2[0; 1] and C3[0; 1], we establish the lower estimate with an explicit constant in approximation by Bernstein polynomials in terms of the second order Ditzian-Totik modulus of smoothness. Several applications to some concrete examples of functions are presented
Self-oscillations in field emission nanowire mechanical resonators: a nanometric DC-AC conversion
We report the observation of self-oscillations in a bottom-up
nanoelectromechanical system (NEMS) during field emission driven by a constant
applied voltage. An electromechanical model is explored that explains the
phenomenon and that can be directly used to develop integrated devices. In this
first study we have already achieved ~50% DC/AC (direct to alternative current)
conversion. Electrical self-oscillations in NEMS open up a new path for the
development of high speed, autonomous nanoresonators, and signal generators and
show that field emission (FE) is a powerful tool for building new
nano-components
Assessment of Implementation of a CAMBRAâ Based Program in a Dental School Environment
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153663/1/jddj002203372013774tb05489x.pd
Current Saturation in Field Emission from H-Passivated Si Nanowires
International audienceThis paper explores the field emission (FE) properties of highly crystalline Si nanowires (NWs) with controlled surface passivation. The NWs were batch-grown by the vapor_liquid_solid process using Au catalysts with no intentional doping. The FE current_voltage characteristics showed quasi-ideal current saturation that resembles those predicted by the basic theory for emission from semiconductors, even at room temperature. In the saturation region, the currents were extremely sensitive to temperature and also increased linearly with voltage drop along the nanowire. The latter permits the estimation of the doping concentration and the carrier lifetime, which is limited by surface recombination. The conductivity could be tuned over 2 orders of magnitude by in situ hydrogen passivation/desorption cycles. This work highlights the role of dangling bonds in surface leakage currents and demonstrates the use of hydrogen passivation for optimizing the FE characteristics of Si NWs
Field emission measure of the time response of individual semiconducting nanowires to laser excitation
International audienceA simple technique is explored to determine the temporal photo-response, s, of individual semiconducting SiC and Si nanowires (NWs), with a high time resolution. Laser-assisted field emission (LAFE) from the NWs is first shown to be highly sensitive to continuous laser illumination. Pulsed illumination is then combined with measurements of the total energy distributions to determine s which were rather large, 4-200 ls. The time response scaled roughly with the square of the NWs length and could be attributed to laser-induced heating. LAFE is thus a new tool for quantifying rapid thermo-optical effects in such nano-objects
Organisation of carbon nanotubes and semiconductor nanowires using lateral alumina templates
International audienceCarbon nanotubes and semiconductor nanowires have been thoroughly studied for the future replacement of silicon-based com- plementary metal oxide semiconductor (CMOS) devices and circuits. However, the organisation of these nanomaterials in dense transistor arrays, where each device is capable of delivering drive currents comparable with those of their silicon counterparts is still a big challenge. Here, we present a novel approach to the organisation of carbon nanotubes and semiconductor nanowires, based on the use of porous lateral alumina templates obtained by the controlled anodic oxidation of aluminium thin films. We discuss the growth of nanomaterials inside the pores of such templates and show the feasibility of our approach. Our first results point to further work on controlling the synthesis of catalyst nanoparticles at the bottom of the pores, these particles being necessary to nucleate and sustain the growth of carbon nanotubes or semiconductor nanowires
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