Classical quasi-trigonometric r−r-matrices of Cremmer-Gervais type and their quantization

We propose a method of quantization of certain Lie bialgebra structures on the polynomial Lie algebras related to quasi-trigonometric solutions of the classical Yang-Baxter equation. The method is based on so-called affinization of certain seaweed algebras and their quantum analogues.Comment: 9 pages, LaTe

Raman spectroscopy study of the interface structure in (CaCuO2)n/(SrTiO3)m superlattices

Raman spectra of CaCuO2/SrTiO3 superlattices show clear spectroscopic marker of two structures formed in CaCuO2 at the interface with SrTiO3. For non-superconducting superlattices, grown in low oxidizing atmosphere, the 425 cm-1 frequency of oxygen vibration in CuO2 planes is the same as for CCO films with infinite layer structure (planar Cu-O coordination). For superconducting superlattices grown in highly oxidizing atmosphere, a 60 cm-1 frequency shift to lower energy occurs. This is ascribed to a change from planar to pyramidal Cu-O coordination because of oxygen incorporation at the interface. Raman spectroscopy proves to be a powerful tool for interface structure investigation

Linear and Second-order Optical Response of the III-V Mono-layer Superlattices

We report the first fully self-consistent calculations of the nonlinear optical properties of superlattices. The materials investigated are mono-layer superlattices with GaP grown on the the top of InP, AlP and GaAs (110) substrates. We use the full-potential linearized augmented plane wave method within the generalized gradient approximation to obtain the frequency dependent dielectric tensor and the second-harmonic-generation susceptibility. The effect of lattice relaxations on the linear optical properties are studied. Our calculations show that the major anisotropy in the optical properties is the result of strain in GaP. This anisotropy is maximum for the superlattice with maximum lattice mismatch between the constituent materials. In order to differentiate the superlattice features from the bulk-like transitions an improvement over the existing effective medium model is proposed. The superlattice features are found to be more pronounced for the second-order than the linear optical response indicating the need for full supercell calculations in determining the correct second-order response.Comment: 9 pages, 4 figures, submitted to Phy. Rev.

The 'Sophistication' Of Exports: A New Measure Of Product Characteristics

Trade data are often classified by product characteristics in the trade, technology and development literature to analyze trade patterns, competitive performance and structural change. However, existing classifications are constrained in that trade data are far more detailed than the industry data on which categories are based (e.g. current classifications only have 4-5 technology groups). We propose a new classification - 'sophistication' - as a means of analyzing product characteristics in great detail, based on the average income of exporting economies. Sophistication captures more than technical characteristics; it includes product differentiation, production fragmentation, resource availability and other factors. However, it has the advantage of providing unique continuous scores for each product at any level of detail. We calculate sophistication scores for 237 exports at the 3-digit SITC level and 766 exports at the 4-digit level for 1990 and 2000 (detailed values can be provided on request). We show sophistication scores for exports by selected countries, technology groups and industries. Our intention is to provide a database for further empirical analysis.

A Validation Framework for the Long Term Preservation of High Energy Physics Data

The study group on data preservation in high energy physics, DPHEP, is moving to a new collaboration structure, which will focus on the implementation of preservation projects, such as those described in the group's large scale report published in 2012. One such project is the development of a validation framework, which checks the compatibility of evolving computing environments and technologies with the experiments software for as long as possible, with the aim of substantially extending the lifetime of the analysis software, and hence of the usability of the data. The framework is designed to automatically test and validate the software and data of an experiment against changes and upgrades to the computing environment, as well as changes to the experiment software itself. Technically, this is realised using a framework capable of hosting a number of virtual machine images, built with different configurations of operating systems and the relevant software, including any necessary external dependencies.Comment: Proceedings of a poster presented at CHEP 2013, Amsterdam, October 14-18 201

Effect of soil waterlogging on below-ground biomass allometric relations in Norway spruce

An increasing importance is assigned to the estimation and verification of carbon stocks in forests. Forestry practice has several long-established and reliable methods for the assessment of aboveground biomass; however we still miss accurate predictors of belowground biomass. A major windthrow event exposing the coarse root systems of Norway spruce trees allowed us to assess the effects of contrasting soil stone and water content on belowground allocation. Increasing stone content decreases root/shoot ratio, while soil waterlogging leads to an increase in this ratio. We constructed allometric relationships for belowground biomass prediction and were able to show that only soil waterlogging significantly impacts model parameters. We showed that diameter at breast height is a reliable predictor of belowground biomass and, once site-specific parameters have been developed, it is possible to accurately estimate belowground biomass in Norway spruce

Study Of Inas/Ga(In)Sb And Inasn/Ga(In)Sb Superlattices By Mbe For Very Long Wavelength Infrared Photodetectors

Infrared (IR) sensors are extremely important in missile defense as well as in satellite-based infrared detection systems. Long-range ballistic missile defense for incoming missile acquisition, tracking, and discrimination requires space-based infrared technology. Hence long wavelength and very long wavelength infrared regimes are extremely important for such applications. The focus of this work is on the investigation of superlattices (SLs) and in particular dilute nitride based SLs for such applications in this infrared region. A comprehensive study of InAs/GaSb, InAs/GaInSb, InAsN/GaSb and InAsN/GaInSb SLs grown by molecular beam epitaxy (MBE) has been carried out using different characterization techniques. Optimization of the structures with growth parameters such as interfacial layers, layer thickness, and material composition will also be discussed. The judicious selection of the above combination of parameters was abetted by theoretical simulation using OPTEL_ZB software. A systematic and detailed study has been made correlating the structural quality, vibrational modes, scanning transmission electron microscope (STEM) micrographs and optical properties of each of the optimized structure of the SL. All the SLs were defect free with sharp interfaces and well defined sublayers as attested by high resolution x-ray diffraction (HRXRD) and asymmetric reciprocal space mapping (RSM) spectra as well as STEM images. The unique feature of this work is the growth of InAsN/GaSb SL which has not been reported elsewhere to the best of our knowledge. This SL shows promise in that thinner layers of InAsN were used for the same strain balancing effect as thicker InAs. Hence the former would improve optical absorption. Since the N in InAsN reduces the overall lattice constant of the material system it added another degree of freedom in strain balancing the structure to the GaSb substrate. A cut off wavelength of ~20 μm was achieved with the InAsN/GaSb SL