12,588 research outputs found
Balloon telescope studies of Venus
Determination of ice clouds and water vapor in Venus atmosphere from balloon observation
Atomistic Hydrodynamics and the Dynamical Hydrophobic Effect in Porous Graphene
Mirroring their role in electrical and optical physics, two-dimensional
crystals are emerging as novel platforms for fluid separations and water
desalination, which are hydrodynamic processes that occur in nanoscale
environments. For numerical simulation to play a predictive and descriptive
role, one must have theoretically sound methods that span orders of magnitude
in physical scales, from the atomistic motions of particles inside the channels
to the large-scale hydrodynamic gradients that drive transport. Here, we use
constraint dynamics to derive a nonequilibrium molecular dynamics method for
simulating steady-state mass flow of a fluid moving through the nanoscopic
spaces of a porous solid. After validating our method on a model system, we use
it to study the hydrophobic effect of water moving through pores of
electrically doped single-layer graphene. The trend in permeability that we
calculate does not follow the hydrophobicity of the membrane, but is instead
governed by a crossover between two competing molecular transport mechanisms.Comment: 6 pages, 3 figure
Emotion Learning and Memory in Schizophrenia
• Prior research indicates that processing of emotional information is particularly problematic for individuals with schizophrenia. • An important component of emotional processing is the accurate encoding and recall of emotionally valenced information. • The current study addresses this matter by investigating performance on a task assessing learning, recall, and recognition in patients with schizophrenia. • In this manner, recall of emotionally valenced information may be investigate
Memory device for two-dimensional radiant energy array computers
A memory device for two dimensional radiant energy array computers was developed, in which the memory device stores digital information in an input array of radiant energy digital signals that are characterized by ordered rows and columns. The memory device contains a radiant energy logic storing device having a pair of input surface locations for receiving a pair of separate radiant energy digital signal arrays and an output surface location adapted to transmit a radiant energy digital signal array. A regenerative feedback device that couples one of the input surface locations to the output surface location in a manner for causing regenerative feedback is also include
Preparation, analysis and release of simulated interplanetary grains into low Earth orbit
Astronomical observations which reflect the optical and dynamical properties of interstellar and interplanetary grains are the primary means of identifying the shape, size, and the chemistry of extraterrestrial grain materials. Except for recent samplings of extraterrestrial particles in near-Earth orbit and in the stratosphere observations were the only method of deducing the properties of extraterrestrial particles. In order to elucidate the detailed characteristics of observed dust, the observations must be compared with theoretical studies, some of which are discussed in this volume, or compared with terrestrial laboratory experiments. The formation and optical characterization of simulated interstellar and interplanetary dust with particular emphasis on studying the properties on irregularly shaped particles were discussed. Efforts to develop the techniques to allow dust experiments to be carried out in low-Earth orbit were discussed, thus extending the conditions under which dust experiments may be performed
Parameterization of the Angular Distribution of Gamma Rays Produced by p-p Interaction in Astronomical Environment
We present the angular distribution of gamma rays produced by proton-proton
interactions in parameterized formulae to facilitate calculations in
astrophysical environments. The parameterization is derived from Monte Carlo
simulations of the up-to-date proton-proton interaction model by Kamae et al.
(2005) and its extension by Kamae et al. (2006). This model includes the
logarithmically rising inelastic cross section, the diffraction dissociation
process and Feynman scaling violation. The extension adds two baryon resonance
contributions: one representing the Delta(1232) and the other representing
multiple resonances around 1600 MeV/c^2. We demonstrate the use of the formulae
by calculating the predicted gamma-ray spectrum for two different cases: the
first is a pencil beam of protons following a power law and the second is a
fanned proton jet with a Gaussian intensity profile impinging on the
surrounding material. In both cases we find that the predicted gamma-ray
spectrum to be dependent on the viewing angle.Comment: 8 pages, 7 figures, figure 7 updated, accepted for publication in
ApJ, text updated to match changes by the editor, two refs updated from
preprints to full journal
Digital voltage-controlled oscillator
Digital voltage-controlled oscillator generates a variable frequency signal controlled linearly about a center frequency with high stability and is phase controlled by an applied voltage. Integration ahead of the digital circuitry provides linear operation with control voltage having appreciable noise components
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