1,930 research outputs found
An Application Case Study on Multi-sensor Data fusion System for Intelligent Process Monitoring
AbstractMulti-sensor data fusion is a technology to enable combining information from several sources in order to form a unified picture. Focusing on the indirect method, an attempt was made to build up a multi-sensor data fusion system to monitor the condition of grinding wheels with force signals and the acoustic emission (AE) signals. An artificial immune algorithm based multi-signals processing method was presented in this paper. The intelligent monitoring system is capable of incremental supervised learning of grinding conditions and quickly pattern recognition, and can continually improve the monitoring precision. The application case indicates that the accuracy of condition identification is about 87%, and able to meet the industrial need on the whole
Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280 K)
We use neutron scattering to study the spin excitations associated with the
stripe antiferromagnetic (AFM) order in semiconducting
KFeSe (= K). We show that the spin wave spectra
can be accurately described by an effective Heisenberg Hamiltonian with highly
anisotropic in-plane couplings at = K. At high temperature (=
K) above , short range magnetic correlation with anisotropic correlation
lengths are observed. Our results suggest that, despite the dramatic difference
in the Fermi surface topology, the in-plane anisotropic magnetic couplings are
a fundamental property of the iron based compounds; this implies that their
antiferromagnetism may originate from local strong correlation effects rather
than weak coupling Fermi surface nesting.Comment: 5 pages, 4 figure
Classical-driving-assisted quantum synchronization in non-Markovian environments
We study the quantum phase synchronization of a driven two-level system (TLS)
coupled to a structured environment and demonstrate that quantum
synchronization can be enhanced by the classical driving field. We use the
Husimi -function to characterize the phase preference and find the in-phase
and anti-phase locking phenomenon in the phase diagram. Remarkably, we show
that the classical driving enables a TLS to reach stable anti-phase locking in
the Markovian regime. However, we find that the synergistic action of classical
driving and non-Markovian effects significantly enhances the in-phase locking.
By introducing the -function and its maximal value to quantify the strength
of synchronization and sketch the synchronization regions, we observe the
typical signatures of the hollowed Arnold tongue in the parameter regions of
synchronization. In the hollowed Arnold tongue, the synchronization regions
exist both inside and outside the tongue while unsynchronized regions only lie
on the boundary line. We also provide an intuitive interpretation of the above
results by using the quasimode theory.Comment: 10 pages, 5 figures, revised versio
Non-Thermal X-ray Properties of Rotation Powered Pulsars and Their Wind Nebulae
We present a statistical study of the non-thermal X-ray emission of 27 young
rotation powered pulsars (RPPs) and 24 pulsar wind nebulae (PWNe) by using the
Chandra and the XMM-Newton observations, which with the high spatial
resolutions enable us to spatially resolve pulsars from their surrounding PWNe.
We obtain the X-ray luminosities and spectra separately for RPPs and PWNe, and
then investigate their distribution and relation to each other as well as the
relation with the pulsar rotational parameters. In the pair-correlation
analysis we find that: (1) the X-ray (2-10 keV) luminosities of both pulsar and
PWN (L_{psr} and L_{pwn}) display a strong correlation with pulsar spin down
power Edot and characteristic age, and the scalings resulting from a simple
linear fit to the data are L_{psr} \propto Edot^{0.92 \pm 0.04} and L_{pwn}
\propto Edot^{1.45 \pm 0.08} (68% confidence level), respectively, however,
both the fits are not statistically acceptable; (2) L_{psr} also shows a
possible weak correlation with pulsar period P and period derivative Pdot,
whereas L_{pwn} manifests a similar weak correlation with Pdot only; (3) The
PWN photon index Gamma_{pwn} is positively correlated with L_{pwn} and
L_{pwn}/Edot. We also found that the PWN X-ray luminosity is typically 1 to 10
times larger than that from the underlying pulsar, and the PWN photon indices
span a range of ~1.5 to ~2. The statistic study of PWN spectral properties
supports the particle wind model in which the X-ray emitting electrons are
accelerated by the termination shock of the wind.Comment: 15 pages, 9 figures, 3 Tables, ApJ accepted version. Substantial
revision, especially luminosity uncertainty taken into accounted and one fig
added. Main conclusions unchange
Steroidal and pregnane glycosides from Ypsilandra thibetica
The whole plants of Ypsilandra thibetica have been analyzed as part of a systematic study on saponin constituents of medicinal plants. This has resulted in the isolation of two new bisdesmosidic furostanol saponins, named ypsilandroside P (1) and ypsilandroside Q (2), and one new pregnane glycoside, named ypsilandroside R (3), together with nine known steroidal glycosides. Their structures were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic hydrolysis. Ypsilandroside P (1) was cytotoxicity against two human tumor cell lines. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s13659-011-0039-z and is accessible for authorized users
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