The largest eigenvalue of the adjacency matrix of networks is a key quantity determining several important dynamical processes on complex networks. Based on this fact, we present a quantitative, objective characteriza...
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The largest eigenvalue of the adjacency matrix of networks is a key quantity determining several important dynamical processes on complex networks. Based on this fact, we present a quantitative, objective characterization of the dynamical importance of network nodes and links in terms of their effect on the largest eigenvalue. We show how our characterization of the dynamical importance of nodes can be affected by degree-degree correlations and network community structure. We discuss how our characterization can be used to optimize techniques for controlling certain network dynamical processes and apply our results to real networks.
Although models of branching in arterial and bronchial trees often predict a dependence of bifurcation parameters on the scale of the bifurcating vessels, direct verification of this dependence by comparison with data...
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Although models of branching in arterial and bronchial trees often predict a dependence of bifurcation parameters on the scale of the bifurcating vessels, direct verification of this dependence by comparison with data is uncommon. We compare measurements of bifurcation parameters of airways and arterial trees of different mammals as a function of scale to general features predicted by theoretical models based on minimization of pumping power and network volume. We find that the size dependence is more complex than existing theories based solely on energy and volume minimization explain, and suggest additional factors that may govern the branching at different scales.
We present a general theory for the onset of coherence in collections of heterogeneous maps interacting via a complex connection network. Our method allows the dynamics of the individual uncoupled systems to be either...
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We present a general theory for the onset of coherence in collections of heterogeneous maps interacting via a complex connection network. Our method allows the dynamics of the individual uncoupled systems to be either chaotic or periodic, and applies generally to networks for which the number of connections per node is large. We find that the critical coupling strength at which a transition to synchrony takes place depends separately on the dynamics of the individual uncoupled systems and on the largest eigenvalue of the adjacency matrix of the coupling network. Our theory directly generalizes the Kuramoto model of equal strength all-to-all coupled phase oscillators to the case of oscillators with more realistic dynamics coupled via a large heterogeneous network.
We are investigating several techniques to obtain time‐dependent magnetic field measurements in wire‐array Z‐pinches and X‐pinches. One general approach is to use “remote sensing” methods whereby a very small se...
We are investigating several techniques to obtain time‐dependent magnetic field measurements in wire‐array Z‐pinches and X‐pinches. One general approach is to use “remote sensing” methods whereby a very small sensor material is placed in the plasma and then is investigated to extract useful information. Faraday rotation of polarized laser light traversing a small area through thin film waveguides coupled to a fine optical fiber is a possibility. While these films may not survive for long in a dense Z‐pinch, they may provide useful information for a significant fraction of the current pulse. We also discuss results of experiments conducted using magnetic CoPt thin films to obtain the maximum magnetic field seen by the film near the end of the load current pulse.
The emission behaviour of InAs/GaSb superlattice photodiodes has been studied in the spectral range between 8 μm and 13 μm. With a radiometric calibration of the experimental set-up the internal quantum efficiency h...
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Statistical fluctuations in the eigenvalues of the scattering, impedance, and admittance matrices of two-port wave-chaotic systems are studied experimentally using a chaotic microwave cavity. These fluctuations are un...
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Statistical fluctuations in the eigenvalues of the scattering, impedance, and admittance matrices of two-port wave-chaotic systems are studied experimentally using a chaotic microwave cavity. These fluctuations are universal in that their properties are dependent only upon the degree of loss in the cavity. We remove the direct processes introduced by the nonideally coupled driving ports through a matrix normalization process that involves the radiation-impedance matrix of the two driving ports. We find good agreement between the experimentally obtained marginal probability density functions (PDFs) of the eigenvalues of the normalized impedance, admittance, and scattering matrix and those from random matrix theory (RMT). We also experimentally study the evolution of the joint PDF of the eigenphases of the normalized scattering matrix as a function of loss. Experimental agreement with the theory by Brouwer and Beenakker for the joint PDF of the magnitude of the eigenvalues of the normalized scattering matrix is also shown.
We report sub-140 nm resolution imaging with 46.9 nm radiation from a compact capillary-discharge laser. This result was obtained using a combination of a Sc/Si multilayercoated Schwarzschild condenser and free-standi...
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This paper presents the nonresonant ultrasonic motor (SPIDER)-driven precision stage control based on an adaptive identification method with a variable forgetting factor (VFF). SPIDER-driven stage has a strong non-lin...
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This paper presents the nonresonant ultrasonic motor (SPIDER)-driven precision stage control based on an adaptive identification method with a variable forgetting factor (VFF). SPIDER-driven stage has a strong non-linearity due to the frictional drive mechanism. Focusing on the VFF, dynamical change of frictional property is detected. Therefore, fast and precise friction compensation can be performed based on the VFF. The validity of both the identification and compensation methods is verified through experiments
Time-resolved mid-infrared pump-probe measurements in a quantum cascade laser operating above threshold reveal gain recovery dynamics to be two-fold: relaxation within a stage on a sub-picosecond scale and transport b...
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ISBN:
(纸本)1557528136
Time-resolved mid-infrared pump-probe measurements in a quantum cascade laser operating above threshold reveal gain recovery dynamics to be two-fold: relaxation within a stage on a sub-picosecond scale and transport between stages on a picosecond scale.
We have studied the temperature behavior of the electrical resistivities ρ(T) in a series of tin‐doped indium‐oxide films with different residual resistivities ρ0 varying from 218 to 568 μΩ cm. We found that the...
We have studied the temperature behavior of the electrical resistivities ρ(T) in a series of tin‐doped indium‐oxide films with different residual resistivities ρ0 varying from 218 to 568 μΩ cm. We found that the temperature dependence of ρ can be well described by the Bloch‐Grüneisen law from 300 K down to about 100 K. In particular, we observed that the strength of the electron‐phonon coupling, βBG (which characterizes a prefactor in the Bloch‐Grüneisen formula) increases linearly with increasing ρ0. This result is not understood in terms of current theoretical concept for electron‐phonon interaction in metals.
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