804 research outputs found
A Formalism for Scattering of Complex Composite Structures. 2 Distributed Reference Points
Recently we developed a formalism for the scattering from linear and acyclic
branched structures build of mutually non-interacting sub-units.{[}C. Svaneborg
and J. S. Pedersen, J. Chem. Phys. 136, 104105 (2012){]} We assumed each
sub-unit has reference points associated with it. These are well defined
positions where sub-units can be linked together. In the present paper, we
generalize the formalism to the case where each reference point can represent a
distribution of potential link positions. We also present a generalized
diagrammatic representation of the formalism. Scattering expressions required
to model rods, polymers, loops, flat circular disks, rigid spheres and
cylinders are derived. and we use them to illustrate the formalism by deriving
the generic scattering expression for micelles and bottle brush structures and
show how the scattering is affected by different choices of potential link
positions.Comment: Paper no. 2 of a serie
Diffraction limited optics for single atom manipulation
We present an optical system designed to capture and observe a single neutral
atom in an optical dipole trap, created by focussing a laser beam using a large
numerical aperture N.A.=0.5 aspheric lens. We experimentally evaluate the
performance of the optical system and show that it is diffraction limited over
a broad spectral range (~ 200 nm) with a large transverse field (+/- 25
microns). The optical tweezer created at the focal point of the lens is able to
trap single atoms of 87Rb and to detect them individually with a large
collection efficiency. We measure the oscillation frequency of the atom in the
dipole trap, and use this value as an independent determination of the waist of
the optical tweezer. Finally, we produce with the same lens two dipole traps
separated by 2.2 microns and show that the imaging system can resolve the two
atoms.Comment: 8 pages, 9 figures; typos corrected and references adde
The Visualities and Aesthetics of Prosecuting Aged Defendants
This is the author accepted manuscript. The final version is available from Brill via the DOI in this recordThe prosecution—whether domestic or international—of international crimes and atrocities may implicate extremely aged defendants. Much has been written about the legalisms that inhere (or not) in trying these barely alive individuals. Very little however has been written about the aesthetics the barely alive encrust into the architecture of courtrooms, the optics these defendants suffuse into the trial process, and the expressive value of punishing them. This is what we seek to do in this project
Contract-Driven Implementation of Choreographies
Choreographies and Contracts are important concepts in Service Oriented Computing. Choreographies are the description of the behaviour of a service system from a global point of view, while contracts are the description of the externally observable message-passing behaviour of a given service. Exploiting some of our previous results about choreography projection and contract refinement, we show how to solve the problem of implementing a choreography via the composition of already available services that are retrieved according to their contracts
Static Safety for an Actor Dedicated Process Calculus by Abstract Interpretation
The actor model eases the definition of concurrent programs with non uniform
behaviors. Static analysis of such a model was previously done in a data-flow
oriented way, with type systems. This approach was based on constraint set
resolution and was not able to deal with precise properties for communications
of behaviors. We present here a new approach, control-flow oriented, based on
the abstract interpretation framework, able to deal with communication of
behaviors. Within our new analyses, we are able to verify most of the previous
properties we observed as well as new ones, principally based on occurrence
counting
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