2,544 research outputs found
Stabilized Radiation Pressure Dominated Ion Acceleration from Thin-foil Targets
We study transverse and longitudinal electron heating effects on the target
stability and the ion spectra in the radiation pressure dominated regime of ion
acceleration by means of multi dimensional particle-in-cell (PIC) simulations.
Efficient ion acceleration occurs when the longitudinal electron temperature is
kept as low as possible. However, tailoring of the transverse electron
temperature is required in view of suppressing the transverse instability,
which can keep the target structure intact for longer duration during the
acceleration stage. We suggest using the surface erosion of the target to
increase the transverse temperature, which improves both the final peak energy
and the spectral quality of the ions in comparison with a normal flat target.Comment: 5 pages, 3 picture
On Spin Dependence of Relativistic Acoustic Geometry
This work makes the first ever attempt to understand the influence of the
black hole background space-time in determining the fundamental properties of
the embedded relativistic acoustic geometry. To accomplish such task, the role
of the spin angular momentum of the astrophysical black hole (the Kerr
parameter -- a representative feature of the background black hole metric)
in estimating the value of the acoustic surface gravity (the representative
feature of the corresponding analogue space time) has been investigated for
axially symmetric inflow of hydrodynamic fluid onto a rotating black hole.
Since almost all astrophysical black holes are supposed to posses some degree
of intrinsic rotation, the influence of the Kerr parameter on classical
analogue models is very important to understand.
For certain values of the initial boundary conditions describing the
aforementioned flow, more than one acoustic horizons, namely two black hole
type and one white hole type, may form, where the surface gravity may become
formally infinite at the acoustic white hole. The connection between the
corresponding analogue Hawking temperature with astrophysically relevant
observables associated with the spectral signature has been discussed.Comment: 22 pages, 11 figures, Comments welcom
Evaluating product search and recommender systems for E-commerce environments
Online systems that help users select the most preferential item from a large electronic catalog are known as product search and recommender systems. Evaluation of various proposed technologies is essential for further development in this area. This paper describes the design and implementation of two user studies in which a particular product search tool, known as example critiquing, was evaluated against a chosen baseline model. The results confirm that example critiquing significantly reduces users' task time and error rate while increasing decision accuracy. Additionally, the results of the second user study show that a particular implementation of example critiquing also made users more confident about their choices. The main contribution is that through these two user studies, an evaluation framework of three criteria was successfully identified, which can be used for evaluating general product search and recommender systems in E-commerce environments. These two experiments and the actual procedures also shed light on some of the most important issues which need to be considered for evaluating such tools, such as the preparation of materials for evaluation, user task design, the context of evaluation, the criteria, the measures and the methodology of result analyse
An inverse problem for semilinear equations involving the fractional Laplacian
Our work concerns the study of inverse problems of heat and wave equations
involving the fractional Laplacian operator with zeroth order nonlinear
perturbations. We recover nonlinear terms in the semilinear equations from the
knowledge of the fractional Dirichlet-to-Neumann type map combined with the
Runge approximation and the unique continuation property of the fractional
Laplacian.Comment: 25 page
Complex field measurement in a single pixel hybrid correlation holography
We propose a new scheme for recovery of complex valued object in a
single-pixel hybrid correlation holography. Idea is to generate an intensity
correlation hologram by correlation of the intensity of a single pixel detector
and digitally propagated two dimensional intensity patterns. The proposed
scheme with theoretical basis is described to reconstruct the objects from a
single pixel detector. An experimental arrangement is proposed and as a first
step to realize the technique, we have simulated the experimental model for
imaging of two different complex objects.Comment: 4 [age
Optical waveform sampling of a 320 Gbits/s serial data signal using a hydrogenated amorphous silicon waveguide
We propose using a hydrogenated amorphous silicon waveguide for ultra-high-speed serial data waveform sampling. 320 Gbit/s serial optical data sampling is experimentally demonstrated with +12 dB intrinsic four wave mixing conversion efficiency
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Cellulose hydrolysis by Clostridium thermocellum is agnostic to substrate structural properties in contrast to fungal cellulases
Evaluating product search and recommender systems for E-commerce environments
Online systems that help users select the most preferential item from a large electronic catalog are known as product search and recommender systems. Evaluation of various proposed technologies is essential for further development in this area. This paper describes the design and implementation of two user studies in which a particular product search tool, known as example critiquing, was evaluated against a chosen baseline model. The results confirm that example critiquing significantly reduces users' task time and error rate while increasing decision accuracy. Additionally, the results of the second user study show that a particular implementation of example critiquing also made users more confident about their choices. The main contribution is that through these two user studies, an evaluation framework of three criteria was successfully identified, which can be used for evaluating general product search and recommender systems in E-commerce environments. These two experiments and the actual procedures also shed light on some of the most important issues which need to be considered for evaluating such tools, such as the preparation of materials for evaluation, user task design, the context of evaluation, the criteria, the measures and the methodology of result analyses
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A Multifunctional Cosolvent Pair Reveals Molecular Principles of Biomass Deconstruction
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