1,801 research outputs found
Experimental Investigation of Plasma Production by Irradiating Solid Hydrogen Foils with an Intense Pulse Laser
Properties and characterization of ALD grown dielectric oxides for MIS structures
We report on an extensive structural and electrical characterization of
under-gate dielectric oxide insulators Al2O3 and HfO2 grown by Atomic Layer
Deposition (ALD). We elaborate the ALD growth window for these oxides, finding
that the 40-100 nm thick layers of both oxides exhibit fine surface flatness
and required amorphous structure. These layers constitute a base for further
metallic gate evaporation to complete the Metal-Insulator-Semiconductor
structure. Our best devices survive energizing up to ~3 MV/cm at 77 K with the
leakage current staying below the state-of-the-art level of 1 nA. At these
conditions the displaced charge corresponds to a change of the sheet carrier
density of 3 \times 1013 cm-2, what promises an effective modulation of the
micromagnetic properties in diluted ferromagnetic semiconductors.Comment: 8 pages, 5 figures, 14 reference
Messungen der Temperatur und Dichte eines Argon-Plasmastrahls mit dem Mach-Zehnder-Interferometer. - Measurements of the Density and the Temperature of an Argon Plasma Jet by Means of a Mach-Zehnder Interferometer
GUARDIANS final report part 1 (draft): a robot swarm assisting a human fire fighter
Emergencies in industrial warehouses are a major concern for fire fighters. The large dimensions together with the development of dense smoke that drastically reduces visibility, represent major challenges. The Guardians robot swarm is designed to assist re ghters in searching a
large warehouse. In this paper we discuss the technology developed for a swarm of robots assisting re ghters. We explain the swarming algorithms which provide the functionality by which the robots react to and follow humans while no communication is required. Next we discuss the wireless communication system, which is a so-called mobile ad-hoc network. The communication network provides also the means to locate the robots and humans. Thus the robot swarm is able to provide guidance information to the humans. Together with the fire fighters we explored how
the robot swarm should feed information back to the human fire fighter. We have designed and experimented with interfaces for presenting swarm based information to human beings
Can Gravitational Instantons Really Constrain Axion Inflation?
Axions play a central role in inflationary model building and other cosmological applications. This is mainly due to their flat potential, which is protected by a global shift symmetry. However, quantum gravity is known to break global symmetries, the crucial effect in the present context being gravitational instantons or Giddings-Strominger wormholes. We attempt to quantify, as model-independently as possible, how large a scalar potential is induced by this general quantum gravity effect. We pay particular attention to the crucial issue which solutions can or cannot be trusted in the presence of a moduli-stabilisation and a Kaluza-Klein scale. An important conclusion is that, due to specific numerical prefactors, the effect is surprisingly small even in UV-completions with the highest possible scale offered by string theory. As we go along, we discuss in detail Euclidean wormholes, cored and extremal instantons, and how the latter arise from 5d Reissner-Nordstrom black holes. We attempt to dispel possible doubts that wormholes contribute to the scalar potential by an explicit calculation. We analyse the role of stabilised dilaton-like moduli. Finally, we argue that Euclidean wormholes may be the objects satisfying the Weak Gravity Conjecture extended to instantons
El impacto sobre las propiedades mecánicas de la saturación de agua de los ladrillos cerámicos contemporáneos y del siglo XIX
The paper presents test results concerning ceramic bricks produced in 1880’s. Bricks were obtained from a building erected as part of Archduke Rudolf barracks in Krakow. The tests helped to specify changes in brick compressive strength and hardness, caused by water saturation in the ceramic material. For comparison purposes, tests were also carried out on contemporary bricks. Tests showed that mechanical properties of the ceramic bricks in the water saturation state were worse than in the dry state. The impact of strong brick moisture on changes of mechanical parameters is essential in terms of safety assessment for brick structures.En el artículo se presentan los resultados del estudio de los ladrillos cerámicos producidos en los años 80 del siglo XIX. Los ladrillos se obtuvieron del edificio que forma parte de un conjunto de cuarteles del archiduque Rudolfo en Cracovia en Polonia. En los estudios se han determinado los cambios de la resistencia a la compresión y la dureza de los ladrillos, por efecto de la saturación de agua del material cerámico. A efectos comparativos, se han realizado también estudios de ladrillos producidos en la actualidad. Se ha comprobado que la saturación de agua de los ladrillos cerámicos lleva consigo una considerable disminución de las propiedades mecánicas. Por lo tanto, el impacto de la alta humedad de los ladrillos sobre el cambio de las propiedades mecánicas constituye un factor significativo en la evaluación de la seguridad en las construcciones de ladrillo
Population Suppression of Western Corn Rootworm by Adult Control with ULV Malathion
ULV malathion (9.7 oz AI/acre) was applied by air to a 16 square-mile area during August of 1968, 1969, and 1970. Adult Diabrotica virgifera LeConte populations were reduced the following season by 39, 54, and 72%. No economic infestations occurred in the treated area the year following any application. Postspray migration of beetles was very limited, but adult migration during the peak emergence period the following season contributed to repopulation of the treated area. Migration and fecundity appear to be density-dependent factors which favor increases under low populations. Area suppression does not appear economically feasible, but adult control in individual fields may be an acceptable alternative to soil insecticides applied for larval control. A model was developed for timing treatments against adults; treatments between Aug. 1–15 should result in adequate population suppression to prevent damage the following season. Mid-August population levels of 1.0 beetle/ plant were an acceptable economic threshold for determining the need for control measures
Modification of emission properties of ZnO layers due to plasmonic near-field coupling to Ag nanoislands
A simple fabrication method of Ag nanoislands on ZnO films is presented.
Continuous wave and time-resolved photoluminescence and transmission are
employed to investigate modifications of visible and UV emissions of ZnO
brought about by coupling to localized surface plasmons residing on Ag
nanoislands. The size of the nanoislands, determining their absorption and
scattering efficiencies, is found to be an important factor governing plasmonic
modification of optical response of ZnO films. The presence of the Ag
nanoislands of appropriate dimensions causes a strong (threefold) increase in
emission intensity and up to 1.5 times faster recombination. The experimental
results are successfully described by model calculations within the Mie theory.Comment: 14 pages, 5 figure
Cholesterol content and intramuscular collagen properties of pectoralis superficialis muscle of quail from different genetic groups
ABSTRACT To study growth performance and meat quality traits (cholesterol content and intramuscular collagen properties) of quail, 3 trials were carried out. Trial 1 used males of generation 19 of the egg type Japanese quail (Coturnix japonica) selected previously (until generation 17) for low (n = 8) or high (n = 7) yolk cholesterol content as well as an unselected control (n = 11). Trial 2 used males of meat Pharaoh quail selected earlier (generations 1 to 6 and 9 to 11) on the basis of BW decrease after periodic deprivation of food (high decrease of weight, n = 10; low decrease of weight, n = 8) and unselected control (n = 10). Trial 3 compared males of English White quail, Manchurian Golden quail, and British Range quail. The birds were raised to 35 d of age. Quail were fed ad libitum commercial diets according to age and had free access to water. At slaughter, all birds were individually weighed (after a fasting period of 12 h), stunned, and decapitated. After the refrigeration period (24 h at 4°C), the left pectoralis superficialis muscle was removed from the carcasses, weighed, vacuum packaged, and stored frozen (−40°C) for analyses of cholesterol and intramuscular collagen (IMC; collagen and crosslink concentration). In trial 1, divergent selection for yolk cholesterol content did not significantly influence pectoralis superficialis muscle weight and IMC crosslinking of Japanese quail, whereas it significantly reduced growth and IMC amount. In addition, it had greater effect on the amount of cholesterol in meat; in fact, the meat of quail with low yolk cholesterol content contained lower cholesterol (−36.6%) than that of birds with high yolk cholesterol content. In trial 2, divergent selection on the basis of Pharaoh quail BW decrease altered IMC crosslinking, leading to variability in meat tenderness of Pharaoh quail. In trial 3, English White quail were significantly heavier than the other breeds
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