3,997 research outputs found
Solar X-ray spectrum reproduced in vacuum
Desired low energy X rays are produced by modifying commercial ion tubes and combining them with standard power supplies and control circuitry. These X rays have less deviation from the solar X ray spectrum in energy and intensity
Role of two-electron processes in the excitation-ionization of lithium atoms by fast ion impact
We study excitation and ionization in the 1.5 MeV/amu O-Li collision
system, which was the subject of a recent reaction-microscope-type experiment
[Fischer \textit{et al.}, Phys. Rev. Lett. \textbf{109}, 113202 (2012)].
Starting from an independent-electron model based on determinantal wave
functions and using single-electron basis generator method and continuum
distorted-wave with eikonal initial-state calculations we show that pure single
ionization of a lithium -shell electron is too weak a process to explain the
measured single differential cross section. Rather, our analysis suggests that
two-electron excitation-ionization processes occur and have to be taken into
account when comparing with the data. Good agreement is obtained only if we
replace the independent-electron calculation by an independent-event model for
one of the excitation-ionization processes and also take a shake-off process
into account
Differential cross sections for single ionization of Li in collisions with fast protons and O ions
We study the process of single ionization of Li in collisions with H and
O projectile ions at 6 MeV and 1.5-MeV/amu impact energies,
respectively. Using the frameworks of the independent-electron model and the
impact parameter picture, fully (FDCS) and doubly (DDCS) differential cross
sections are evaluated in the continuum distorted-wave with eikonal
initial-state approximation. Comparisons are made with the recent measurements
of LaForge \textit{et al} [J. Phys. B \textbf{46} 031001 (2013)] for the DDCS
and Hubele \textit{et al} [Phys. Rev. Lett. \textbf{110} 133201 (2013)] for the
FDCS, respectively. For O impact inclusion of the heavy particle (NN)
interaction in the calculations is crucial and effects of polarization due to
the presence of the projectile ion have also to be taken into account for
getting very good agreement with the measured data. Our calculation reproduces
the satellite peak structure seen in the FDCS for the Li(2s) measurement, which
we explain as being formed by a combination of the binary and NN interactions
Doubly-differential cross section calculations for -shell vacancy production in lithium by fast O ion impact
Inner-shell vacancy production for the O-Li collision system at 1.5
MeV/amu is studied theoretically. The theory combines single-electron
amplitudes for each electron in the system to extract multielectron information
about the collision process. Doubly-differential cross sections obtained in
this way are then compared with the recent experimental data by LaForge et al.
[J. Phys. B 46, 031001 (2013)] yielding good resemblance, especially for low
outgoing electron energy. A careful analysis of the processes that contribute
to inner-shell vacancy production shows that the improvement of the results as
compared to single-active-electron calculations can be attributed to the
leading role of two-electron excitation-ionization processes
Potato virus Y transmitting aphids in a Finnish seed potato area
The aphid-transmissible Potato virus Y is a major problem in seed potato production (Valkonen , 2007).
The aphid flight activity was monitored from mid-June to the end of August with a suction trap and with yellow pan traps in 2007 and 2008.
Previous studies have concluded that potato colonising aphids are not the main vectors of Potato virus Y
Communicating Mental Illness in the Black American Community
Human-human interactions are of central relevance for the success in professional and occupational environments, which also substantially influence quality of life. This is especially true in the case of individuals with high-functioning autism (HFA), who experience deficits in social cognition that often lead to social exclusion and unemployment. Despite good education and high motivation, individuals with HFA do not reach employment rates that are substantially higher than 50 %. This is an alarmingly high rate of unemployment considering that the United Nations have recently emphasized the inclusion of handicapped persons as a mandatory human right. To date, the specific needs of autistic persons with respect to their working environment are largely unexplored. It remains moreover an open question how support systems and activities, including newly developed communication devices for professional environments of individuals with HFA, should look like. The German health and social care systems are not adequately prepared for the proper support of this population. This leads us to suggest that supported employment programs should be developed for adults with HFA that specifically address their needs and requirements. Such programs should comprise (1) the adequate assessment of HFA, including a neuropsychological profile and an individual matching of persons' preferences with requirements of the working place, (2) on-the-job coaching activities that include systematic communication and interaction training, and (3) instruction of non-autistic peers, including colleagues and supervisors, about weaknesses and strengths of HFA
Data compression for the Cassini radio and plasma wave instrument
The Cassini Radio and Plasma Wave Science experiment will employ data compression to make effective use of the available data telemetry bandwidth. Some compression will be achieved by use of a lossless data compression chip and some by software in a dedicated 80C85 processor. A description of the instrument and data compression system are included in this report. Also, the selection of data compression systems and acceptability of data degradation is addressed
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