Development of optical coatings for cos thin film solar cells third quarterly report, jun. 1 - aug. 1, 1965

Sputtering of glass coatings on cadmium sulfide thin film solar cell

Development of optical coatings for cds thin film solar cells second quarterly report, 1 mar. - 1 jun. 1965

Optical coatings for cadmium sulfide thin film solar cell

Gamma-Ray Burster Counterparts: HST Blue and Ultraviolet Data

The surest solution of the Gamma Ray Burst (GRB) mystery is to find an unambiguous low-energy quiescent counterpart. However, to date no reasonable candidates have been identified in the x-ray, optical, infrared, or radio ranges. The Hubble Space Telescope (HST) has now allowed for the first deep ultraviolet searches for quiescent counterparts. This paper reports on multiepoch ultraviolet searches of five GRB positions with HST. We found no sources with significant ultraviolet excesses, variability, parallax, or proper motion in any of the burst error regions. In particular, we see no sources similar to that proposed as a counterpart to the GRB970228. While this negative result is disappointing, it still has good utility for its strict limits on the no-host-galaxy problem in cosmological models of GRBs. For most cosmological models (with peak luminosity 6X10^50 erg/s), the absolute B magnitude of any possible host galaxy must be fainter than -15.5 to -17.4. These smallest boxes for some of the brightest bursts provide the most critical test, and our limits are a severe problem for all published cosmological burst models.Comment: 15 pages, 2 ps figures, accepted for publication in the Astrophysical Journa

Research and development in CdS photovoltaic cells Third quarterly report, 29 Dec. 1965 - 29 Mar. 1966

Barrier formation studies of copper sulfide and cadmium sulfide in photovoltaic cell

Statistical characterization of airplane delays

The aviation industry is of great importance for a globally connected economy. Customer satisfaction with airlines and airport performance is considerably influenced by how much flights are delayed. But how should the delay be quantified with thousands of flights for each airport and airline? Here, we present a statistical analysis of arrival delays at several UK airports between 2018 and 2020. We establish a procedure to compare both mean delay and extreme events among airlines and airports, identifying a power-law decay of large delays. Furthermore, we note drastic changes in plane delay statistics during the COVID-19 pandemic. Finally, we find that delays are described by a superposition of simple distributions, leading to a superstatistics

Analysis of electron-positron momentum spectra of metallic alloys as supported by first-principles calculations

Electron-positron momentum distributions measured by the coincidence Doppler broadening method can be used in the chemical analysis of the annihilation environment, typically a vacancy-impurity complex in a solid. In the present work, we study possibilities for a quantitative analysis, i.e., for distinguishing the average numbers of different atomic species around the defect. First-principles electronic structure calculations self-consistently determining electron and positron densities and ion positions are performed for vacancy-solute complexes in Al-Cu, Al-Mg-Cu, and Al-Mg-Cu-Ag alloys. The ensuing simulated coincidence Doppler broadening spectra are compared with measured ones for defect identification. A linear fitting procedure, which uses the spectra for positrons trapped at vacancies in pure constituent metals as components, has previously been employed to find the relative percentages of different atomic species around the vacancy [A. Somoza et al. Phys. Rev. B 65, 094107 (2002)]. We test the reliability of the procedure by the help of first-principles results for vacancy-solute complexes and vacancies in constituent metals.Comment: Submitted to Physical Review B on September 19 2006. Revised version submitted on November 8 2006. Published on February 14 200

Full genome sequencing of a human-like H1N2 swine influenza virus.

Projeto/Plano de Ação: 02.11.01.006

Lossy data compression with random gates

We introduce a new protocol for a lossy data compression algorithm which is based on constraint satisfaction gates. We show that the theoretical capacity of algorithms built from standard parity-check gates converges exponentially fast to the Shannon's bound when the number of variables seen by each gate increases. We then generalize this approach by introducing random gates. They have theoretical performances nearly as good as parity checks, but they offer the great advantage that the encoding can be done in linear time using the Survey Inspired Decimation algorithm, a powerful algorithm for constraint satisfaction problems derived from statistical physics

A tribenzylidenemethane–tantalum compound: some experiences with 'inversion twinning'

The six-electron-donating ligand tribenzylidenemethandiide has been used to form a tantalum (group 5) mimic, (η^5-cyclopentadienyl)(η^4-tribenzylidenemethandiide)dimethyltantalum, of a group 4 bent metallocene. The material crystallizes with two molecules in the asymmetric unit with quite different packing arrangements, although the overall structures of the two are similar. The Cp and methyl ligands are disordered about a threefold axis. Crystal data: [Ta{(C_7H_6)_3C}(C_5H_5)(CH_3), trigonal P31c, with a = 12.681 (3), c = 16.124 (5) Å, V = 2245.5 (7) Å^3, T = 293 K, Z = 4, M_r = 558.47, D_x = 1.65 g cm^(-3), F(000) = 1104, Mo Kα, λ = 0.71073 Å, µ = 4.91 mm^(-1), R = 0.020 for 1319 reflections with F_o > 4σ(F_o); S = 2.18. Because of crystal decay, three separate crystals were needed for a full data set. These polar (but achiral) crystals showed apparently differing amounts of inversion twinning, leading to problems in accurately merging the three data sets and refining the structure. These problems are discussed briefly