We present a microfluidic device capable of generating micro-scale gradients of nitric oxide (NO) in cell cultures. NO release is achieved through the proton mediated reaction of a water-soluble low molecular weight p...
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This work utilizes pulsed, melt-mediated laser crystallization techniques to control the spatial distribution of crystalline zones within an as sputter-deposited amorphous matrix. Since shape memory responses stem fro...
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ISBN:
(纸本)9780912035888
This work utilizes pulsed, melt-mediated laser crystallization techniques to control the spatial distribution of crystalline zones within an as sputter-deposited amorphous matrix. Since shape memory responses stem from crystallographic shifts, only the selectively crystallized regions exhibit these properties. This process provides not only spatial control over the shape memory response, but potentially, through proper use of operational parameters, the shape memory response itself, i.e. phase transformation temperature, transformation strain, recovery stress etc. The solidification process is monitored in situ via transient reflectance. Furthermore, the effects of varying energy density within the irradiated region are examined with respect to the resulting micro-structure via atomic force microscopy (AFM), electron backscatter diffraction (EBSD) and x-ray diffraction (XRD).
The observation of helices and coils in nano-tube/-fiber (NT/NF) syntheses is explained on the basis of the interactions between specific catalyst particles and the growing nanostructure. In addition to rationalizing ...
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Substantial R&D activities are presently under way toward the development of advanced pulsed-laser-based production tools and processes that can enable sophisticated yet effective crystallization of Si films for m...
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Functional Magnetic Resonance Imaging (fMRI) provides dynamical access into the complex functioning of the human brain, detailing the hemodynamic activity of thousands of voxels during hundreds of sequential time poin...
ISBN:
(纸本)9781605603520
Functional Magnetic Resonance Imaging (fMRI) provides dynamical access into the complex functioning of the human brain, detailing the hemodynamic activity of thousands of voxels during hundreds of sequential time points. One approach towards illuminating the connection between fMRI and cognitive function is through decoding; how do the time series of voxel activities combine to provide information about internal and external experience? Here we seek models of fMRI decoding which are balanced between the simplicity of their interpretation and the effectiveness of their prediction. We use signals from a subject immersed in virtual reality to compare global and local methods of prediction applying both linear and nonlinear techniques of dimensionality reduction. We find that the prediction of complex stimuli is remarkably low-dimensional, saturating with less than 100 features. In particular, we build effective models based on the decorrelated components of cognitive activity in the classically-defined Brodmann areas. For some of the stimuli, the top predictive areas were surprisingly transparent, including Wernicke's area for verbal instructions, visual cortex for facial and body features, and visual-temporal regions for velocity. Direct sensory experience resulted in the most robust predictions, with the highest correlation (c ~ 0.8) between the predicted and experienced time series of verbal instructions. Techniques based on non-linear dimensionality reduction (Laplacian eigenmaps) performed similarly. The interpretability and relative simplicity of our approach provides a conceptual basis upon which to build more sophisticated techniques for fMRI decoding and offers a window into cognitive function during dynamic, natural experience.
We propose a hybrid quantum circuit with both charge and flux qubits connected to a large Josephson junction that gives rise to an effective interqubit coupling controlled by the external magnetic flux. This switchabl...
We propose a hybrid quantum circuit with both charge and flux qubits connected to a large Josephson junction that gives rise to an effective interqubit coupling controlled by the external magnetic flux. This switchable interqubit coupling can be used to transfer back and forth an arbitrary superposition state between the charge qubit and the flux qubit working at the optimal point. The proposed hybrid circuit provides a promising quantum memory because the flux qubit at the optimal point can store the tranferred quantum state for a relatively long time.
Using inverse statistical-mechanical optimization techniques, we have discovered isotropic pair interaction potentials with strongly repulsive cores that cause the tetrahedrally coordinated diamond and wurtzite lattic...
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Using inverse statistical-mechanical optimization techniques, we have discovered isotropic pair interaction potentials with strongly repulsive cores that cause the tetrahedrally coordinated diamond and wurtzite lattices to stabilize, as evidenced by lattice sums, phonon spectra, positive-energy defects, and self-assembly in classical molecular dynamics simulations. These results challenge conventional thinking that such open lattices can only be created via directional covalent interactions observed in nature. Thus, our discovery adds to fundamental understanding of the nature of the solid state by showing that isotropic interactions enable the self-assembly of open crystal structures with a broader range of coordination number than previously thought. Our work is important technologically because of its direct relevance generally to the science of self-assembly and specifically to photonic crystal fabrication.
作者：
S. AshhabKoji MaruyamaFranco NoriFrontier Research System
Institute of Physical and Chemical Research (RIKEN) Wako-shi Saitama 351-0198 Japan CREST
Japan Science and Technology Agency Kawaguchi Saitama 332–0012 Japan Physics Department
Michigan Center for Theoretical Physics Applied Physics Program Center for the Study of Complex Systems University of Michigan Ann Arbor Michigan 48109-1040 USA
We discuss the possibility of observing quantum nonlocality using the so-called mode entanglement, analyzing the differences between different types of particles in this context. We first discuss the role of coherent ...
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We discuss the possibility of observing quantum nonlocality using the so-called mode entanglement, analyzing the differences between different types of particles in this context. We first discuss the role of coherent states in such experiments, and we comment on the existence of coherent states in nature. The discussion of coherent states naturally raises questions about the role of particle statistics in this problem. Although the Pauli exclusion principle precludes coherent states with a large number of fermionic particles, we find that a large number of fermionic coherent states, each containing at most one particle, can be used to achieve the same effect as a bosonic coherent state for the purposes of this problem. The discussion of superselection rules arises naturally in this context, because their applicability to a given situation prohibits the use of coherent states. This limitation particularly affects the scenario that we propose for detecting the mode entanglement of fermionic particles.
We have used Bragg rod x-ray diffraction combined with a direct method of phase retrieval to extract atomic resolution electron-density maps of a complementary series of heteroepitaxial III-V semiconductor samples. Fr...
We have used Bragg rod x-ray diffraction combined with a direct method of phase retrieval to extract atomic resolution electron-density maps of a complementary series of heteroepitaxial III-V semiconductor samples. From the three-dimensional electron-density maps we derive the monolayer spacings, the chemical compositions, and the characteristics of the bonding for all atomic planes in the film and across the film-substrate interface. InAs films grown on GaSb(001) under two different As conditions (using dimer or tetramer forms) both showed conformal roughness and mixed GaAs∕InSb interfacial bonding character. The As tetramer conditions favored InSb bonding at the interface while, in the case of the dimer, the percentages corresponding to GaAs and InSb bonding were equal within the experimental error. The GaSb film grown on InAs(001) displayed significant In and As interdiffusion and had a relatively large fraction of GaAs-like bonds at the interface.
At concentrations near the maximum allowed by steric repulsion, swimming bacteria form a dynamical state exhibiting extended spatiotemporal coherence. The viscous fluid into which locomotive energy of individual micro...
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At concentrations near the maximum allowed by steric repulsion, swimming bacteria form a dynamical state exhibiting extended spatiotemporal coherence. The viscous fluid into which locomotive energy of individual microorganisms is transferred also carries interactions that drive the coherence. The concentration dependence of correlations in the collective state is probed here with a novel technique that herds bacteria into condensed populations of adjustable concentration. For the particular thin-film geometry employed, the correlation lengths vary smoothly and monotonically through the transition from individual to collective behavior.
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