13,010 research outputs found
Evaluating the reliability of NAND multiplexing with PRISM
Probabilistic-model checking is a formal verification technique for analyzing the reliability and performance of systems exhibiting stochastic behavior. In this paper, we demonstrate the applicability of this approach and, in particular, the probabilistic-model-checking tool PRISM to the evaluation of reliability and redundancy of defect-tolerant systems in the field of computer-aided design. We illustrate the technique with an example due to von Neumann, namely NAND multiplexing. We show how, having constructed a model of a defect-tolerant system incorporating probabilistic assumptions about its defects, it is straightforward to compute a range of reliability measures and investigate how they are affected by slight variations in the behavior of the system. This allows a designer to evaluate, for example, the tradeoff between redundancy and reliability in the design. We also highlight errors in analytically computed reliability bounds, recently published for the same case study
Optimal operating conditions and characteristics of acetone/CaF_2 detector for inverse photoemission spectroscopy
Performance and characteristics of a band-pass photon detector using acetone
gas and CaF_2 window (acetone/CaF_2) have been studied and compared with an
ethanol/MgF_2 detector. The optimal operating conditions are found to be 4 mbar
acetone pressure and 745+/-20 V anode voltage. The count rate obtained by us is
about a factor of 3 higher than what has been reported earlier for the acetone
detector. Unlike other gas filled detectors, this detector works in the
proportional region with very small dead time (4 micro sec). A detector
band-pass of 0.48+/-0.01 eV FWHM is obtained.Comment: Review of Scientific Instruments 76, 066102 (2005
Exact Solution of Return Hysteresis Loops in One Dimensional Random Field Ising Model at Zero Temperature
Minor hysteresis loops within the main loop are obtained analytically and
exactly in the one-dimensional ferromagnetic random field Ising-model at zero
temperature. Numerical simulations of the model show excellent agreement with
the analytical results
Deuteron Momentum Distribution in KD2HPO4
The momentum distribution in KD2PO4(DKDP) has been measured using neutron
Compton scattering above and below the weakly first order
paraelectric-ferroelectric phase transition(T=229K). There is very litte
difference between the two distributions, and no sign of the coherence over two
locations for the proton observed in the paraelectric phase, as in KH2PO4(KDP).
We conclude that the tunnel splitting must be much less than 20mev. The width
of the distribution indicates that the effective potential for DKDP is
significantly softer than that for KDP. As electronic structure calculations
indicate that the stiffness of the potential increases with the size of the
coherent region locally undergoing soft mode fluctuations, we conclude that
there is a mass dependent quantum coherence length in both systems.Comment: 6 pages 5 figure
Development Trends in Wind Energy Conversion System: A Review
Wind energy for electricity production today is a mature, competitive and virtually pollution-free technology widely used in many areas of the world. Wind energy conversion systems have become a focal point in the research of renewable energy sources. This is not only due to the rapid advances in the size of wind generators but also for the improvement of energy electronics and their applicability in wind energy extraction. This paper deals with the recent developments in wind energy conversion systems, their classifications, choice of generators and their social, economic and environmental advantages and disadvantages, a review of the interconnection issues of distributed resources including wind power with electric power systems.
DOI: 10.17762/ijritcc2321-8169.150710
Nonlinear wave interactions in quantum magnetoplasmas
Nonlinear interactions involving electrostatic upper-hybrid (UH),
ion-cyclotron (IC), lower-hybrid (LH), and Alfven waves in quantum
magnetoplasmas are considered. For this purpose, the quantum hydrodynamical
equations are used to derive the governing equations for nonlinearly coupled
UH, IC, LH, and Alfven waves. The equations are then Fourier analyzed to obtain
nonlinear dispersion relations, which admit both decay and modulational
instabilities of the UH waves at quantum scales. The growth rates of the
instabilities are presented. They can be useful in applications of our work to
diagnostics in laboratory and astrophysical settings.Comment: 15 pages, to appear in Physics of Plasma
Critical Hysteresis in Random Field XY and Heisenberg Models
We study zero-temperature hysteresis in random-field XY and Heisenberg models
in the zero-frequency limit of a cyclic driving field. We consider three
distributions of the random field and present exact solutions in the mean field
limit. The results show a strong effect of the form of disorder on critical
hysteresis as well as the shape of hysteresis loops. A discrepancy with an
earlier study based on the renormalization group is resolved.Comment: 10 pages, 6 figures; this is published version (added some text and
references
Advanced Magnetic Resonance Imaging in Glioblastoma: A Review
INTRODUCTION
In 2017, it is estimated that 26,070 patients will be diagnosed with a malignant primary brain tumor in the United States, with more than half having the diagnosis of glioblas- toma (GBM).1 Magnetic resonance imaging (MRI) is a widely utilized examination in the diagnosis and post-treatment management of patients with glioblastoma; standard modalities available from any clinical MRI scanner, including T1, T2, T2-FLAIR, and T1-contrast-enhanced (T1CE) sequences, provide critical clinical information. In the last decade, advanced imaging modalities are increasingly utilized to further charac- terize glioblastomas. These include multi-parametric MRI sequences, such as dynamic contrast enhancement (DCE), dynamic susceptibility contrast (DSC), diffusion tensor imaging (DTI), functional imaging, and spectroscopy (MRS), to further characterize glioblastomas, and significant efforts are ongoing to implement these advanced imaging modalities into improved clinical workflows and personalized therapy approaches. A contemporary review of standard and advanced MR imaging in clinical neuro-oncologic practice is presented
Synthesis and characterization of polyurethane microspheres
A novel particle forming polymerization technique for the preparation of
polyurethane microspheres with particle size in the range 0.1-100 micron is
described. The method is general, applicable to wide variety of diols and isocyanates
and is very simple. The key to successful particle forming polymerization is the use
of novel steric stabilizers, such as, a reactive diol containing two primary hydroxyl
groups with a long hydrophobic acrylate ester moiety and an amphiphilic block
copolymer. The effect of various reactiorr variables on the particle forming
polymerization process will be discussed
Ab initio Hartree-Fock Born effective charges of LiH, LiF, LiCl, NaF, and NaCl
We use the Berry-phase-based theory of macroscopic polarization of dielectric
crystals formulated in terms of Wannier functions, and state-of-the-art
Gaussian basis functions, to obtain benchmark ab initio Hartree-Fock values of
the Born effective charges of ionic compounds LiH, LiF, LiCl, NaF, and NaCl. We
find excellent agreement with the experimental values for all the compounds
except LiCl and NaCl, for which the disagreement with the experiments is close
to 10% and 16%, respectively. This may imply the importance of many-body
effects in those systems.Comment: 11 pages, Revtex, 2 figures (included), to appear in Phys. Rev. B
April 15, 200
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