216 research outputs found
A Note On 3Solitary Wave Solutions of the Compound Burgers-Korteweg-de Vries Equation"
The goal of this note is to construct a class of traveling solitary wave
solutions for the compound Burgers-Korteweg-de Vries equation by means of a
hyperbolic ansatz
Urban Link Travel Time Estimation Based on Low Frequency Probe Vehicle Data
To improve the accuracy and robustness of urban link travel time estimation with limited resources, this research developed a methodology to estimate the urban link travel time using low frequency GPS probe vehicle data. First, focusing on the case without reporting points for the GPS probe vehicle on the target link in the current estimation time window, a virtual report point creation model based on the K-Nearest Neighbour Rule was proposed. Then an improved back propagation neural network model was used to estimate the link travel time. The proposed method was applied to a case study based on an arterial road in Changchun, China: comparisons with the traditional artificial neural network method and the spatiotemporal moving average method revealed that the proposed method offered a higher estimation accuracy and better robustness
Huge magnetostriction in superconducting single-crystalline BaFeNiAs
The performance of iron-based superconductors in high magnetic fields plays
an important role for their practical application. In this work, we measured
the magnetostriction and magnetization of BaFeNiAs
single crystals using pulsed magnetic fields up to 60 T and static magnetic
fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the
order of 10) was observed in the direction of the twin boundaries. The
magnetization measurements evidence a high critical-current density due to
strong bulk pinning. By using magnetization data with an exponential
flux-pinning model, we can reproduce the magnetostriction curves qualitatively.
This result shows that the magnetostriction of
BaFeNiAs can be well explained by a
flux-pinning-induced mechanism.Comment: 4 pages, 3 figure
High magnetic field phase diagram and weak FM breaking in (Ni0.93Co0.07)3V2O8
We present magnetostriction and thermal expansion measurements on
multiferroic (Ni0.93Co0.07)3V2O8. The high field phase diagrams up to 33 T
along the a, b and c directions are built. For H//a, as the magnetic field
increases, two intermediate phases appear between the incommensurate phase and
the paramagnetic phase at about 7 K, and then a magnetically induced phase
appears above the paramagnetic phase. For H//b,thermal expansion measurement
indicates a mutation in the spin lattice coupling of the high field phases. The
interlaced phase boundary suggests a mixed state in the optical high field
phase. For H//c, an intermediate phase between the commensurate phase and the
incommensurate phase is detected. A nonlinear boundary between the intermediate
phase and the low temperature incommensurate phase, and a clear boundary
between the commensurate phase and the paramagnetic phase are found. These
results indicate that doping Co2+ breaks the weak ferromagnetic moment of the
commensurate phase, which exists in the parent compound Ni3V2O8 and
(Ni0.9Co0.1)3V2O8. This nonlinear influence reflects complicated spin
modulation in Ni3V2O8 by doping Co2+.Comment: 7 pages, 4 figure
A Simple and Rapid Puncture Method for Draining Hematoma in Pontine Hemorrhage
We present a patient with pontine hemorrhage. On admission, the patient was in a comatose state (Glasgow coma scale, 3). Due to rapid deterioration of his breathing, we immediately performed a direct puncture to the hematoma site. We present a simple and rapid puncture method for drainage of hematomas. The method is described and discussed in detail in this article. The described technique may be beneficial in emergency situations where the condition of the patient, particularly their respiration is declining rapidly
Broadband Bioimpedance Spectroscopy Based on a Multifrequency Mixed Excitation and Nuttall Windowed FFT Algorithm
Bioimpedance spectroscopy (BIS) has become an important clinical indicator for monitoring the pathological status of biological tissues, and multifrequency simultaneous measurement of BIS may provide more accurate diagnostic information compared with the traditional frequency-sweep measurement technology. This paper proposes a BIS multifrequency simultaneous measurement method based on multifrequency mixed (MFM) signal excitation and a Nuttall windowed interpolation FFT algorithm. Firstly, the excitation source adopts the nine-frequency MFM signal f(9,t), which has excellent spectral characteristic and is very suitable for BIS measurement. On this basis, a Nuttall window is adopted to truncate sample data, and an interpolation FFT algorithm based on Nuttall window is built to perform spectral analysis, in which the parameter correction formula is provided based on polynomial approximation. A BIS measurement simulation experiment is performed on an RC three-element equivalent circuit, and results on the 9 primary harmonic frequencies ranging from 3.9 kHz to 1 MHz show a high accuracy with the impedance amplitude relative error |Ez|<0.3%, and the phase absolute error |Ep|<0.1°. This paper validates the feasibility of BIS multifrequency simultaneous measurement method and establishes an algorithm foundation for the development of practical broadband BIS measurement system
A phase transition driven by subtle distortion without broken symmetry on spin, charge and lattice in Layered LnCu4-{\delta}P2(Ln=Eu, Sr)
In the scenario of Landau phase transition theory in condensed matter
physics, any thermal dynamic phase transition must be subject to some kind of
broken symmetries, that are relative to its spin, charge, orbital and lattice.
Here we report a rare phase transition at Tp ~120 K or 140 K in layered
materials LnCu4-{\delta}P2 (Ln=Eu, Sr) driven by a subtle structural-distortion
without any broken symmetry on charge, spin and lattice. The variations of the
lattice parameters, ({\Delta}Lc/Lc) ~ 0.013% or 0.062%, verified by thermal
expansion, is much less than that for a typical crystalline phase transition
(~0.5-1%), but the significant anomaly in heat capacity provides clear evidence
of its intrinsic nature of thermodynamic transition.Comment: 13 pages, 4 figure
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