5,695 research outputs found
Development and research of data transmission system using M-sequence
В исследовании синтезируется система передачи данных высокой помехозащищенности. Разработаны передающее и приемное устройства, реализующие метод расширения спектра, осуществляющие кодирование и декодирование передаваемого сообщения М-последовательностью. Схемы синтезированы в среде SysGen, эксперимент проведен на ПЛИС фирмы XILINX семейства Kintex7. Получение данных передатчиком осуществлялось с помощью стандарта «UART» со скоростью передачи 1,5 Мб/с. Эксперимент установил, что работоспособность системы ограничивается отношением мощности сигнала и помехи равной -14 дБ.A data transmission system with high noise immunity is synthesized. Transmitting and receiving devices, implementing the spread spectrum and carrying out transmitted message encoding and decoding by m‑sequence, are designed. Schemes are synthesized by using the SysGen software. The experiment is performed with Kintex7 PLD developed by XILINX. The system is based on the use of the standard «UART» with a rate of 1.5 Mbit/s. The experiment found that the system performance is limited by the signal-to-noise ratio equaled to -14 dB
Phase transition and anomalous electronic behavior in layered dichalcogenide CuS (covellite) probed by NQR
Nuclear quadrupole resonance (NQR) on copper nuclei has been applied for
studies of the electronic properties of quasi-two-dimensional low-temperature
superconductor CuS (covellite) in the temperature region between 1.47 and 290
K. Two NQR signals corresponding to two non-equivalent sites of copper in the
structure, Cu(1) and Cu(2), has been found. The temperature dependences of
copper quadrupole frequencies, line-widths and spin-lattice relaxation rates,
which so far had never been investigated so precisely for this material,
altogether demonstrate the structural phase transition near 55 K, which
accompanies transformations of electronic spectrum not typical for simple
metals. The analysis of NQR results and their comparison with literature data
show that the valence of copper ions at both sites is intermediate in character
between monovalent and divalent states with the dominant of the former. It has
been found that there is a strong hybridization of Cu(1) and Cu(2) conduction
bands at low temperatures, indicating that the charge delocalization between
these ions takes place even in 2D regime. Based on our data, the occurrence of
energy gap, charge fluctuations and charge-density waves, as well as the nature
of phase transition in CuS are discussed. It is concluded that some physical
properties of CuS are similar to those of high-temperature superconductors
(HTSC) in normal state.Comment: to be publishe
The Road Towards the ILC: Higgs, Top/QCD, Loops
The International Linear e+e- Collider (ILC) could go into operation in the
second half of the upcoming decade. Experimental analyses and theory
calculations for the physics at the ILC are currently performed. We review
recent progress, as presented at the LCWS06 in Bangalore, India, in the fields
of Higgs boson physics and top/QCD. Also the area of loop calculations,
necessary to achieve the required theory precision, is included.Comment: 7 pages, 1 figure. Plenary talk given at the LCWS06 March 2006,
Bangalore, India. Top part slightly enlarged, references adde
Higgs production with large transverse momentum in hadronic collisions at next-to-leading order
Inclusive associated production of a light Higgs boson (m_H < m_t) with one
jet in pp collisions is studied in next-to-leading order QCD. Transverse
momentum (p_T < 30 GeV) and rapidity distributions of the Higgs boson are
calculated for the LHC in the large top-quark mass limit. It is pointed out
that, as much as in the case of inclusive Higgs production, the K-factor of
this process is large (~1.6) and depends weakly on the kinematics in a wide
range of transverse momentum and rapidity intervals. Our result confirms
previous suggestions that the production channel p+p -> H+jet ->
gamma+gamma+jet gives a measurable signal for Higgs production at the LHC in
the mass range 100-140 GeV, crucial also for the ultimate test of the Minimal
Supersymmetric Standard Model.Comment: 7 pages, 3 eps figures include
Gluino Pair Production at Linear e^+e^- Colliders
We study the potential of high-energy linear colliders for the
production of gluino pairs within the Minimal Supersymmetric Standard Model
(MSSM). In this model, the process is mediated by
quark/squark loops, dominantly of the third generation, where the mixing of
left- and right-handed states can become large. Taking into account realistic
beam polarization effects, photon and -boson exchange, and current mass
exclusion limits, we scan the MSSM parameter space for various
center-of-mass energies to determine the regions, where gluino production
should be visible.Comment: 22 pages, 9 figure
Determination of Filtration Properties of a Deformable Porous-Fractured Bed from the Results of Hydrodynamic Investigations of Horizontal Wells
© 2014, Springer Science+Business Media New York. A computational algorithm has been proposed for interpretation of results of hydrodynamic investigations of horizontal wells in unsteady regimes of filtration in deformable porous-fractured beds. The proposed approach makes it possible to evaluate the dependence of the permeability coefficient of fractures on pressure. A study has been made of the dynamics of change in the bottom-hole pressure after bringing a horizontal well into production and shutting it down in the nonlinear elastic regime of filtration of the fluid in a porous-fractured bed
Temporal coding at the immature depolarizing gabaergic synapse
In the developing hippocampus, GABA exerts depolarizing and excitatory actions and contributes to the generation of neuronal network driven giant depolarizing potentials (GDPs). Here, we studied spike time coding at immature GABAergic synapses and its impact on synchronization of the neuronal network during GDPs in the neonatal (postnatal days P2-6) rat hippocampal slices. Using extracellular recordings, we found that the delays of action potentials (APs) evoked by synaptic activation of GABA(A) receptors are long (mean, 65 ms) and variable (within a time window of 10-200 ms). During patch-clamp recordings, depolarizing GABAergic responses were mainly subthreshold and their amplification by persistent sodium conductance was required to trigger APs. AP delays at GABAergic synapses shortened and their variability reduced with an increase in intracellular chloride concentration during whole-cell recordings. Negative shift of the GABA reversal potential (EGABA) with low concentrations of bumetanide, or potentiation of GABA(A) receptors with diazepam reduced GDPs amplitude, desynchronized neuronal firing during GDPs and slowed down GDPs propagation. Partial blockade of GABA(A) receptors with bicuculline increased neuronal synchronization and accelerated GDPs propagation. We propose that spike timing at depolarizing GABA synapses is determined by intracellular chloride concentration. At physiological levels of intracellular chloride GABAergic depolarization does not reach the action potential threshold and amplification of GABAergic responses by non-inactivating sodium conductance is required for postsynaptic AP initiation. Slow and variable excitation at GABAergic synapse determines the level of neuronal synchrony and the rate of GDPs propagation in the developing hippocampus. © 2010 Valeeva, Abdullin, Tyzio, Skorinkin, Nikolski, Ben-Ari and Khazipov
Dark matter and Colliders searches in the MSSM
We study the complementarity between dark matter experiments (direct
detection and indirect detections) and accelerator facilities (the CERN LHC and
a TeV Linear Collider) in the framework of the
constrained Minimal Supersymmetric Standard Model (MSSM). We show how
non--universality in the scalar and gaugino sectors can affect the experimental
prospects to discover the supersymmetric particles. The future experiments will
cover a large part of the parameter space of the MSSM favored by WMAP
constraint on the relic density, but there still exist some regions beyond
reach for some extreme (fine tuned) values of the supersymmetric parameters.
Whereas the Focus Point region characterized by heavy scalars will be easily
probed by experiments searching for dark matter, the regions with heavy
gauginos and light sfermions will be accessible more easily by collider
experiments. More informations on both supersymmetry and astrophysics
parameters can be thus obtained by correlating the different signals.Comment: 25 pages, 10 figures, corrected typos and reference adde
Tevatron-for-LHC Report: Preparations for Discoveries
This is the "TeV4LHC" report of the "Physics Landscapes" Working Group,
focused on facilitating the start-up of physics explorations at the LHC by
using the experience gained at the Tevatron. We present experimental and
theoretical results that can be employed to probe various scenarios for physics
beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte
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