39,407 research outputs found
Fabrication of large tungsten structures by chemical vapor deposition
Process is accomplished by reducing tungsten hexafluoride with hydrogen. Metallic tungsten of essentially 100 percent purity and density is produced and built up as dense deposit on heated mandrel assembly. Process variations are building up, sealing or bonding refractory metals at temperatures below transition temperatures of base metal substrates
Proposal for demonstrating the Hong-Ou-Mandel effect with matter waves
The Hong-Ou-Mandel (HOM) effect is a striking demonstration of destructive
quantum interference between pairs of indistinguishable bosons, realised so far
only with massless photons. Here we propose an experiment which can realise
this effect in the matter-wave regime using pair-correlated atoms produced via
a collision of two Bose-Einstein condensates and subjected to two laser induced
Bragg pulses. We formulate a novel measurement protocol appropriate for the
multimode matter-wave field, which---unlike the typical two-mode optical
case---bypasses the need for repeated measurements under different displacement
settings of the beam-splitter, thus dramatically reducing the number of
experimental runs required to map out the interference visibility. The protocol
can be utilised in related matter-wave schemes; here we focus on condensate
collisions and by simulating the entire experiment we predict a HOM-dip
visibility of ~69%. By being larger than 50%, such a visibility highlights
strong quantum correlations between the atoms and paves the way for a possible
demonstration of a Bell inequality violation with massive particles in a
related Rarity-Tapster setup.Comment: Essentially the same version as v2, except in Nature Communications
style; for Supplementary Information see the source fil
Bacillus subtilis regulatory protein GerE
GerE is the latest-acting of a series of factors which regulate gene expression in the mother cell during sporulation in Bacillus. The gene encoding GerE has been cloned from B. subtilis and overexpressed in Escherichia coli. Purified GerE has been crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. The small plate-like crystals belong to the monoclinic space group C2 and diffract beyond 2.2 Angstrom resolution with a synchrotron radiation X-ray source
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Innervation and Muscle Cell Infiltration of Plastic Compressed Collagen Constructs
Abstract not available
User interface evaluation of serious games for students with intellectual disability
We have designed and evaluated around 10 serious games under the EU Leonardo Transfer of Innovation Project: Game On Extra Time (GOET) project http://goet-project.eu/. The project supports people with learning disabilities and additional sensory impairments in getting and keeping a job by helping them to learn, via games-based learning; skills that will help them in their working day. These games help students to learn how to prepare themselves for work, dealing with everyday situations at work, including money management, travelling independently etc. This paper is concerned with the potential of serious games as effective and engaging learning resources for people with intellectual disabilities. In this paper we will address questions related to the design and evaluation of such games, and our design solutions to suit the individual learning needs of our target audiences
Use of ERTS-1 imagery to interpret wind-erosion hazard in the Sandhills of Nebraska
There are no author-identified significant results in this report
Application of ERTS-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska
Interpretations of imagery from the Earth Resources Technology Satellite (ERTS-1) indicate that soil associations and attendant range sites can be identified on the basis of vegetation and topography using multi-temporal imagery. Optical density measurements of imagery from the visible red band of the multispectral scanner (MSS band 5) obtained during the growing season were related to field measurements of vegetative biomass, a factor that closely parallels range condition class on specific range sites. ERTS-1 imagery also permitted inventory and assessment of center-pivot irrigation systems in the Sand Hills region in relation to soil and topographic conditions and energy requirements
Equilibrium states for the Bose gas
The generating functional of the cyclic representation of the CCR (Canonical
Commutation Relations) representation for the thermodynamic limit of the grand
canonical ensemble of the free Bose gas with attractive boundary conditions is
rigorously computed. We use it to study the condensate localization as a
function of the homothety point for the thermodynamic limit using a sequence of
growing convex containers. The Kac function is explicitly obtained proving
non-equivalence of ensembles in the condensate region in spite of the
condensate density being zero locally.Comment: 21 pages, no figure
Distributed memory in a heterogeneous network, as used in the CERN-PS complex timing system
The Distributed Table Manager (DTM) is a fast and efficient utility for distributing named binary data structures called Tables, of arbitrary size and structure, around a heterogeneous network of computers to a set of registered clients. The Tables are transmitted over a UDP network between DTM servers in network format, where the servers perform the conversions to and from host format for local clients. The servers provide clients with synchronization mechanisms, a choice of network data flows, and table options such as keeping table disc copies, shared memory or heap memory table allocation, table read/write permissions, and table subnet broadcasting. DTM has been designed to be easily maintainable, and to automatically recover from the type of errors typically encountered in a large control system network. The DTM system is based on a three level server daemon hierarchy, in which an inter daemon protocol handles network failures, and incorporates recovery procedures which will guarantee table consistency when communications are re-established. These protocols are implemented over a communications layer which performs the data conversions, packet splitting, error-correction with retry, and time out handling. The same communications layer is used to implement the application program interface which calls on the server daemon for client services. DTM is a registration based system, in which communications are established dynamically as needed, and tables are distributed only to the clients who have registered their interest in them. The registration protocols include mechanisms to recover from daemon re-launches, and clean up after aborted clients
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