20,653 research outputs found
Opacity data for HCN and HNC from a new ab initio line list
A new extensive ab initio rotation-vibration HCN/HNC line list is presented. The line list contains rotation-vibration energy levels, line frequencies, and line strengths for transitions between states with energy less than 18,000 cm-1 and with J≤60. This line list greatly improves the quality and range of HCN/HNC data available. It is presently the most extensive and most accurate ab initio HCN/HNC line list in existence. It is hoped that this data set will be used in models of C star atmospheres and elsewhere
Probabilistic Reachability Analysis for Large Scale Stochastic Hybrid Systems
This paper studies probabilistic reachability analysis for large scale stochastic hybrid systems (SHS) as a problem of rare event estimation. In literature, advanced rare event estimation theory has recently been embedded within a stochastic analysis framework, and this has led to significant novel results in rare event estimation for a diffusion process using sequential MC simulation. This paper presents this rare event estimation theory directly in terms of probabilistic reachability analysis of an SHS, and develops novel theory which allows to extend the novel results for application to a large scale SHS where a very huge number of rare discrete modes may contribute significantly to the reach probability. Essentially, the approach taken is to introduce an aggregation of the discrete modes, and to develop importance sampling relative to the rare switching between the aggregation modes. The practical working of this approach is demonstrated for the safety verification of an advanced air traffic control example
Temperature dependence of spin-cluster resonance intensity in RbFeCl3·2H2O
The spin-cluster resonance intensity is observed as a function of temperature in the pseudo-one-dimensional canted Ising metamagnet RbFeCl3·2H2O. For T 0.7 TN a pure one-dimensional Ising model gives a good description of the observed intensities. For T TN the intensity decreases rapidly as a function of temperature due to the destruction of the local ordering around a spin-cluster. The measured value of the intrachain interaction Ja/k of -36 K is in good agreement with earlier measurements on spin-cluster excitations
Soil Properties and their Influence on Grassland Production under Low Input and Organic Farming Conditions
End of project reportThis project set out to identify soil properties that most influence grassland production under low mineral nitrogen input conditions. Sixteen farms were selected in Counties Limerick and Clare and the soil sampled. Soil physical and chemical characteristics and soil biological aspects involved in the carbon and nitrogen cycles were studied in the laboratory. Nutrient additions to farms as well as the nature of grazing by livestock (numbers, types of grazing animals, grazing practices), grassland management, and production from the farms were recorded
A Model-independent Description of New Physics effects in e+e- to t tbar
We study the potential of a future collider for the search of
anomalous gamma t t bar and Z t t bar couplings, assuming that CP-invariance
holds. This is done in a model-independent way, considering that all six
possible couplings do appear. Two experimental situations are envisaged, with
and without electron beam polarization. Observability limits in the form of
domains in the 6-dimensional parameter space are established. Illustrations for
specific constrained models are also presented and implications for new physics
searches are discussed.Comment: 26 pages and 5 figures. e-mail: [email protected]
High quality YBa2Cu3Ox ultra-thin films and Y/Pr/Y multilayers made by a modified RF-magnetron sputtering technique
High quality ĉ-axis oriented thin and ultra-thin films have been grown in situ on (100) surfaces of ZrO2, SrTiO3 and MgO. Sharp transitions were observed with Tc,zero of 87–91 K for films thicker than 70 Å. On atomically polished MgO substrates films as thin as 15 Å revealed a full transition to superconductivity above 45.5 K. The critical current density at 77 K was found to be strongly dependent on film thickness. A maximum value was found for a 100 Å film with 8 × 106A/cm2 at 77 K. Also, YBCO/PBCO/YBCO multilayer thin films have been fabricated in situ by the same technique. The epitaxy is maintained throughout the whole multilayer system. The superconducting properties of YBa2Cu3Ox layers do not change compared to single layers. Interdiffusion and possible chemical reaction close to the interfaces can be neglected.\ud
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Planar graph coloring avoiding monochromatic subgraphs: trees and paths make things difficult
We consider the problem of coloring a planar graph with the minimum number of colors such that each color class avoids one or more forbidden graphs as subgraphs. We perform a detailed study of the computational complexity of this problem
Controlled preparation of all high-Tc SNS-type edge junctions and DC SQUIDs
High-Tc SNS-type Josephson junctions and DC SQUIDs were successfully fabricated using hetero-epitaxially grown multilayers of YBa2Cu3Ox and PrBa2Cu3Ox. These layers are c-axis oriented and hence edges of the multilayers give rise to a current flow in the ab-plane between the electrodes of a Josephson junction. The necessary structuring was done by Ar ion beam etching. The individual junctions exhibit a supercurrent up to 80 K. The IcRn-product of these junctions usually has a lower limit of 8 mV at 4.2 K. Voltage modulation of the first DC SQUIDs can be observed up to 66 K. Details on the fabrication and measurements are presented
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