Cathodoluminescence studies of phosphors in a scanning electron microscope

Cathodoluminescence studies are reported of phosphors in a field emission scanning electron microscope (FESEM). A number of phosphor materials have been studied and exhibited a pronounced comet-like structure at high scan rates, because the particle continued to emit light after the beam had moved onto subsequent pixels. Image analysis has been used to study the loss of brightness along the tail and hence to determine the decay time of the materials. This technique provides a simple and convenient way to study the decay times of individual particles

Preliminary Report: Feeding Flax Straw to Cattle

Introduction: This circular gives the results of feeding flax straw to cattle. Reports show that flax was introduced into New England and Virginia, in the early colonial days, and grown chiefly for its fiber. Later its cultivation as a seed crop spread westward with the settlement of new lands. South Dakota ranks third among the states in the production of flax. In the statistical report, issued by the South Dakota Department of Agriculture, for 1930, we find that every county in the state is credited with growing flax. The largest acreage is reported from Perkins County in the West River country and the smallest from Union county in the Southeastern part of the state, which county is one of the smallest in the state. Of the 711,442 acres, 40,862 were grown west of the Missouri River. In this connection it might be well to state that according to the last census of the United States Department of Commerce, over one-third of the cattle population of the state is credited to the West River country. The by-product of the industry, the straw, is still used for manufacturing purposes, but the chances are that more flax straw produced on the farms in South Dakota is used for feeding livestock than for manufacturing purposes. (See more in text

Gravitation and Electromagnetism as Geometrical Objects of a Riemann-Cartan Spacetime Structure

In this paper we first show that any coupled system consisting of a gravitational plus a free electromagnetic field can be described geometrically in the sense that both Maxwell equations and Einstein equation having as source term the energy-momentum of the electromagnetic field can be derived from a geometrical Lagrangian proportional to the scalar curvature R of a particular kind of Riemann-Cartan spacetime structure, where those fields are identified as geometrical objects of the structure. We show moreover that the contorsion tensor of the particular Riemann-Cartan spacetime structure of our theory encodes the same information as the one contained in Chern-Simons term that is proportional to the spin density of the electromagnetic field. Next we show that by adding to the geometrical Lagrangian a term describing the interaction of a electromagnetic current with a general electromagnetic plus the gravitational field and a term describing the matter carrier of the current we get Maxwell equations with source term and Einstein equation having as source term the sum of the energy-momentum tensors of the electromagnetic and matter terms. Finally modeling by dust charged matter the carrier of the electromagnetic current we get the Lorentz force equation. Moreover, we prove that our theory is gauge invariant. We also briefly discuss our reasons for the present enterprise.Comment: In this version some few misprints have been corrected and a remark has changed place. Paper will appear in Advances in Applied Clifford Algebra

Photoluminescence Study of Symmetry-Related Transitions in the Spectrum of Y2O3:Tb3+

Herein we describe the results of a study on the photoluminescence of cubic nanosized Y2O3:Tb3+. These results confirm our earlier conclusions based on cathodoluminescence about the energy flow from excited Tb3+ in a S6 lattice site to Tb3+ in a C2 sit

Blue and Red Cathodoluminescent Emission of Y2O3:Eu Phosphor Studied as a Function of Temperature in a Transmission Electron Microscope

Combined EELS, CL and STEM imaging are used to characterize and study Y2O3:Eu to confirm the variation in CL properties and photo-luminescent properties observed. The synthetic procedures used have facilitated this material to manifest a strong blue emission at low temperature with the expected red emission dominating at room temperature

Local Policy Search in a Convex Space and Conservative Policy Iteration as Boosted Policy Search

International audienceLocal Policy Search is a popular reinforcement learning approach for handling large state spaces. Formally, it searches locally in a parameterized policy space in order to maximize the associated value function averaged over some pre-defined distribution. The best one can hope in general from such an approach is to get a local optimum of this criterion. The first contribution of this article is the following surprising result: if the policy space is convex, any (approximate) local optimum enjoys a global performance guarantee. Unfortunately, the convexity assumption is strong: it is not satisfied by commonly used parameterizations and designing a parameterization that induces this property seems hard. A natural so-lution to alleviate this issue consists in deriving an algorithm that solves the local policy search problem using a boosting approach (constrained to the convex hull of the policy space). The resulting algorithm turns out to be a slight generalization of conservative policy iteration; thus, our second contribution is to highlight an original connection between local policy search and approximate dynamic pro-gramming

The Synthesis, Characterisation and Potential of Eu 3+ Doped Molybdate Phosphors for White Light Emitting Diodes

A wide variety of Eu3+ doped molybdate phosphors were synthesised using the solid state reaction route and their photoluminescent properties were compared. Their crystal structures were investigated. A relationship between cell size and emission intensity was apparent. The implications of this for phosphor design are discussed.The authors are grateful to the Technology Strategy Board (TSB) (UK) for financial funding in the form of TSB Technology programs for the NovelLEDs program TP/6/EPH/6/S/K2522J and the EPSRC for funding the PURPOSE program

Nurses\u27 Alumnae Association Bulletin - Volume 2 Number 3

The Jefferson Nurse Letter from the President Delegates to Biennial Convention Attention Blood Transfusion - Plasma Unit Life in the Army Nurse Corps Secretary\u27s Report Elected to New Office 1892-1942 Progress or Alumnae Association 1892-1942 Report of the School of Nursing Staff News Please Change My Address Air Cooled Red Cross Report Fingerprinting Graduates in the U.S. Army and Navy Degrees Received Promotions Jubilee Report Engagements Marriages Births New Positions - 1941-1942 New Positions on the Nursing Staff of the Hospita

Development of high temperature, radiation hard detectors based on diamond

© 2016 Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response

Geometric Quantization of Topological Gauge Theories

We study the symplectic quantization of Abelian gauge theories in $2+1$ space-time dimensions with the introduction of a topological Chern-Simons term.Comment: 13 pages, plain TEX, IF/UFRJ/9