Calcium-free Solid Solutions in the System Ba7F12Cl2−xBrx (x<1.5), a Single-component White Phosphor Host

We have recently prepared solid solutions of Ba∼6.3Ca∼0.7F12Cl2−xBrx with x ranging from 0 to 2. In this work, the synthesis and single crystal X-ray structure of calcium-free crystals of Ba∼6.9Na∼0.2F12Br0.6Cl1.4 (space group P63/m, a=10.6024(10), c=4.2034(4)Å), Ba∼6.9Na∼0.2F12Br1.4 Cl0.6 (space group P63/m, a=10.6155(9), c=4.2355(4)Å) and Ba∼6.9Na∼0.2Br1.32Cl0.68F12 (space group P63/m, a=10.6218(9), c=4.2284(4)Å) are reported. These crystals systematically present additional electron density at the 0 0 0.25 position which is associated with the presence of small, but significant amounts of Na+ ions in the crysta

Members of the PbFCI-Type Family: Possible Candidates for Room-Temperature Photochemical Hole Burning

We report on crystal growth and about physico-chemical studies on SryBa1-yFClxBr1-x (y = 0, 0.5, and 1) compounds doped with Sm. Persistent spectral hole burning at 300 K is further reported on Sr0.5Ba0.5FCl0.5Br0.5:Sm single crystals

A SUCCESSFUL ATHLETIC TALENT DEVELOPMENT ENVIRONMENT - A HOLISTIC ECOLOGICAL CASE STUDY OF AN ELITE COLLEGE SOCCER PROGRAM

A holistic ecological approach (HEA) was used to investigate ecological factors influencing the athletic talent development process in an elite men's college soccer program. Methods of data collection included interviews, participant observations, and analysis of documents. College soccer has been experiencing various challenges over the past decade with the expansion of the professional soccer landscape and more professional playing opportunities in North America. College soccer has been disregarded by professional clubs in the U.S., and elite youth players often forego a college career and sign a professional contract. This case study examined the development environment college soccer provides for elite players striving to transition to the elite senior level while pursuing a university degree. The environment studied provides a unique combination where elite athletes are integrated in an elite university environment. Coaches focus on holistic long-term development of players, meaning developing the person behind the player and help develop a growth mindset and other social, psycho-social, and psychological competencies. The environment is centered around a relationship between student-athletes and a support network designed to help players balance their academic, personal, and academic responsibilities. Furthermore, the environment is characterized by a strong, open, and cohesive organizational culture. The university, athletic department, and soccer team share core values that are coherent and build on each other. The imbalanced competition schedule of college soccer was highlighted as a major barrier to long-term development of players and adaptations could make the environment even more successful in transitioning players to the senior elite level.Master of Art

Europæiske udstødningsnormer for motorkøretøjer

Indlægget gør status for aktiviteter i EU, der vedrører reguleringen af ud-stødningsgasser fra motorkøretøjer.I september 2005 fremlagde Kommissionen en Temastrategi for luftforure-ning. Et af elementerne til at opnå forbedret luftkvalitet, er en stramning af reguleringen af udstødningsgasser fra motorkøretøjer. På den baggrund fremsatte Kommissionen i december 2005 forslag til nor-mer for person- og varebiler (Euro 5). Forslaget forventes at træde i kraft omkring 2010. Indlægget fokuserer på baggrund, indhold og status for Euro 5 forslaget.Det vigtigste aspekt i forslaget er, at der gennemføres en stramning i grænseværdierne for køretøjers emission af partikler og NOx. Der er desuden fremlagt forslag fra flere medlemslande om, at der allerede nu fastsættes et næste trin af grænseværdier (Euro 6) for NOx

Europæiske udstødningsnormer for motorkøretøjer

Indlægget gør status for aktiviteter i EU, der vedrører reguleringen af udstødningsgasser fra motorkøretøjer. I september 2005 fremlagde Kommissionen en Temastrategi for luftforurening. Et af elementerne til at opnå forbedret luftkvalitet, er en stramning af reguleringen af udstødningsgasser fra motorkøretøjer. På den baggrund fremsatte Kommissionen i december 2005 forslag til normer for person- og varebiler (Euro 5). Forslaget forventes at træde i kraft omkring 2010. Indlægget fokuserer på baggrund, indhold og status for Euro 5 forslaget. Det vigtigste aspekt i forslaget er, at der gennemføres en stramning i grænseværdierne for køretøjers emission af partikler og NOx. Der er desuden fremlagt forslag fra flere medlemslande om, at der allerede nu fastsættes et næste trin af grænseværdier (Euro 6) for NOx

Magnetodielectric effect of Bi6Fe2Ti3O18 film under an ultra-low magnetic field

Good quality and fine grain Bi6Fe2Ti3O18 magnetic ferroelectric films with single-phase layered perovskite structure have been successfully prepared via metal organic decomposition (MOD) method. Results of low-temperature magnetocapacitance measurements reveal that an ultra-low magnetic field of 10 Oe can produce a nontrivial magnetodielectric (MD) response in zero-field-cooling condition, and the relative variation of dielectric constants in magnetic field is positive, i.e., MD=0.05, when T<55K, but negative with a maximum of MD=-0.14 when 55K<T<190K. The magnetodielectric effect appears a sign change at 55K, which is due to transition from antiferromagnetic to weak ferromagnetic; and vanishes abruptly around 190K, which is thought to be associated with order-disorder transition of iron ion at B site of perovskite structures. The ultra-low-field magnetodielectric behaviour of Bi6Fe2Ti3O18 film has been discussed in the light of quasi-two-dimension unique nature of local spin order in ferroelectric film. Our results allow expectation on low-cost applications of detectors and switches for extremely weak magnetic fields in a wide temperature range 55K-190K.Comment: 10 pages 4 figures, planned to submit to J. Phys.: Condensed Matte

Large electric-field induced strain in BiFeO3 ceramics

Large bipolar strain of up to 0.36% (peak-to-peak value) was measured in BiFeO3 ceramics at low frequency (0.1 Hz) and large amplitude (140 kV/cm) of the driving field. This strain is comparable to that achievable in highly efficient Pb-based perovskite ceramics, such as Pb(Zr,Ti)O3 and Pb(Mg,Nb)O3-PbTiO3. The strain showed a strong dependence on the field frequency and is likely largely associated with domain switching involving predominantly non-180{\deg} domain walls. In addition, rearrangement of charged defects by applying electric field of low frequency depins these domain walls, resulting in a more efficient switching and, consequently, an increased response

Quantifying Morphology and Diffusion Properties of Mesoporous Carbon from High-Fidelity 3D Reconstructions

A reliable quantitative analysis in electron tomography, which depends on the segmentation of the three-dimensional reconstruction, is challenging because of constraints during tilt-series acquisition (missing wedge) and reconstruction artifacts introduced by reconstruction algorithms such as the Simultaneous Iterative Reconstruction Technique (SIRT) and Discrete Algebraic Reconstruction Technique (DART). We have carefully evaluated the fidelity of segmented reconstructions analyzing a disordered mesoporous carbon used as support in catalysis. Using experimental scanning transmission electron microscopy (STEM) tomography data as well as realistic phantoms, we have quantitatively analyzed the effect on the morphological description as well as on diffusion properties (based on a random-walk particle-tracking simulation) to understand the role of porosity in catalysis. The morphological description of the pore structure can be obtained reliably both using SIRT and DART reconstructions even in the presence of a limited missing wedge. However, the measured pore volume is sensitive to the threshold settings, which are difficult to define globally for SIRT reconstructions. This leads to noticeable variations of the diffusion coefficients in the case of SIRT reconstructions, whereas DART reconstructions resulted in more reliable data. In addition, the anisotropy of the determined diffusion properties was evaluated, which was significant in the presence of a limited missing wedge for SIRT and strongly reduced for DART