16,578 research outputs found
Adsorption of atoms and molecules upon the surface of a single crystal and chemical reactions that take place upon the surface /low energy electron diffraction/ Annual progress report, 1966-1967
Low energy electron diffraction research of chemical interactions of gases with single crystal metal surfaces, and gas adsorption on nickel and tungsten surface
Hydrogen and oxygen on a /110/ nickel surface
Hydrogen-oxygen reaction on nickel surface, electron diffraction stud
Paying attention to meaning
Several paradigms show that responses to one event
compromise responses to a second event for around 500 ms.
Such effects are generally attributed to attentional capacity
limitations associated with processing information in the first
event. In a task in which targets could be distinguished only by
their meaning, we varied the semantic relationship between
distractors and targets following at different lags. Semantic
relatedness alone produced a classic attentional blink. We conclude
by discussing how attention theory might best accommodate
these new effects
Is a Simple Collisionless Relic Dark Matter Particle Ruled Out?
The central densities of dark matter (DM) halos are much lower than predicted
in cold DM models of structure formation. Confirmation that they have cores
with a finite central density would allow us to rule out many popular types of
collisionless particle as candidates for DM. Any model that leads to cusped
halos (such as cold DM) is already facing serious difficulties on small scales
and hot DM models have been excluded. Here I show that fermionic warm DM is
inconsistent with the wide range of phase space densities in the DM halos of
well-observed nearby galaxies.Comment: 6 pages, 1 figure, LaTeX uses emulateapj.sty, revised version to
appear in ApJ Letters. Argument clarified and strengthened in response to
criticism, conclusions little change
Radiochemical synthesis of pure anhydrous metal halides
Method uses radiation chemistry as practical tool for inorganic preparations and in particular deposition of metals by irradiation of their aqueous metal salt solutions with high energy electrons. Higher valence metal halide is dissolved in organic liquid and exposed to high energy electrons. This causes metal halide to be reduced to a lower valence metal halide
Ammonia adsorption and decomposition on a tungsten /211/ surface
Ammonia adsorption and decomposition on tungsten 211 surface studied by mass spectrometry, electron diffraction, and changes in work functio
First steps in the oxidation of a /110/ nickel surface
Initial steps in oxidation of nickel surface studied using low energy back-reflection electron diffractio
Production of pure metals
A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner
Land use mapping in Erie County, Pennsylvania: A pilot study
The author has identified the following significant results. A pilot study was conducted to determine the feasibility of mapping land use in the Great Lakes Basin area utilizing ERTS-1 data. Small streams were clearly defined by the presence of trees along their length in predominantly agricultural country. Field patterns were easily differentiated from forested areas; dairy and beef farms were differentiated from other farmlands, but no attempt was made to identify crops. Large railroad lines and major highway systems were identified. The city of Erie and several smaller towns were identified, as well as residential areas between these towns, and docks along the shoreline in Erie. Marshes, forests, and beaches within Presque Isle State Park were correctly identified, using the DCLUS program. Bay water was differentiated from lake water, with a small amount of misclassification
Trapping of hydrogen atoms in X-irradiated salts at room temperature and the decay kinetics
The salts (hypophosphites, formates, a phosphite, a phosphate, and an oxalate) were X-irradiated, whereby hydrogen formed chemically by a radiolytic process becomes trapped in the solid. By room temperature vacuum extraction, the kinetics for the evolution of this trapped hydrogen was studied mass spectrometrically. All salts except two exhibited second-order kinetics. The two exceptions (NaH2PO2(H2O) and K2HPO4) showed first-order kinetics. Based on experimental results, the escape of hydrogen involves three steps: the diffusion of hydrogen atoms from the bulk to the surface, association of these atoms on the surface (rate controlling step for second-order hydrogen evolution), and the desorption of molecular hydrogen from the surface. The hydrogen does not escape if the irradiated salt is stored in air, apparently because adsorbed air molecules occupy surface sites required in the escape mechanism
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