9,917 research outputs found
An investigation of computer coupled automatic activation analysis and remote lunar analysis Quarterly progress report, 1 Nov. 1962 - 1 Feb. 1963
Mark II automatic activation analysis system, influence of radiation on silver ion migration in mice, selenium determination in submicrogram quantities, and remote lunar analysi
Development of neutron activation analysis procedures for the determination of oxygen in potassium final report, period ending 15 dec. 1964
Neutron activation analysis for determination of oxygen in potassiu
A preliminary assessment of small steam Rankine and Brayton point-focusing solar modules
A preliminary assessment of three conceptual point-focusing distributed solar modules is presented. The basic power conversion units consist of small Brayton or Rankine engines individually coupled to two-axis, tracking, point-focusing solar collectors. An array of such modules can be linked together, via electric transport, to form a small power station. Each module also can be utilized on a stand-alone basis, as an individual power source
Buffalo National River Ecosystems - Part II
The priorities were established for the Buffalo National River Ecosystem Studies through meetings and correspondence with Mr. Roland Wauer and other personnel of the Office of Natural Sciences, Southwest Region of the National Park Service. These priorities were set forth in the appendix of contract no. CX 700050443 dated May 21, 1975
Mass Predictions for Pseudoscalar Charmonium and Bottomonium Hybrids in QCD Sum-Rules
Masses of the pseudoscalar charmonium and bottomonium
hybrids are determined using QCD Laplace sum-rules. The effects of the
dimension-six gluon condensate are included in our analysis and result in a
stable sum-rule analysis, whereas previous studies of these states were unable
to optimize mass predictions. The pseudoscalar charmonium hybrid is predicted
to have a mass of approximately 3.8 GeV and the corresponding bottomonium
prediction is 10.6 GeV. Calculating the full correlation function, rather than
only the imaginary part, is shown to be necessary for accurate formulation of
the sum-rules. The charmonium hybrid mass prediction is discussed within the
context of the X Y Z resonances.Comment: 10 pages, 7 embedded figures. Analysis extended and refined in v
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A novel design process of low cost 3D printed ambidextrous finger designed for an ambidextrous robotic hand
This paper presents the novel mechanical design of an ambidextrous finger specifically designed for an ambidextrous anthropomorphic robotic hand actuated by pneumatic artificial muscles. The ambidextrous nature of design allows fingers to perform both left and right hand movements. The aim of our design is to reduce the number of actuators, increase the range of movements with best possible range ideally greater than a common human finger. Four prototypes are discussed in this paper; first prototype is focused on the choice of material and to consider the possible ways to reduce friction. Second prototype is designed to investigate the tendons routing configurations. Aim of third and fourth prototype is to improve the overall performance and to maximize the grasping force. Finally, a unified design (Final design) is presented in great detail. Comparison of all prototypes is done from different angles to evaluate the best design. The kinematic features of intermediate mode have been analysed to optimize both the flexibility and the robustness of the system, as well as to minimize the number of pneumatic muscles. The final design of an ambidextrous finger has developed, tested and 3D printed
Quantum transport in carbon nanotubes
Carbon nanotubes are a versatile material in which many aspects of condensed
matter physics come together. Recent discoveries, enabled by sophisticated
fabrication, have uncovered new phenomena that completely change our
understanding of transport in these devices, especially the role of the spin
and valley degrees of freedom. This review describes the modern understanding
of transport through nanotube devices.
Unlike conventional semiconductors, electrons in nanotubes have two angular
momentum quantum numbers, arising from spin and from valley freedom. We focus
on the interplay between the two. In single quantum dots defined in short
lengths of nanotube, the energy levels associated with each degree of freedom,
and the spin-orbit coupling between them, are revealed by Coulomb blockade
spectroscopy. In double quantum dots, the combination of quantum numbers
modifies the selection rules of Pauli blockade. This can be exploited to read
out spin and valley qubits, and to measure the decay of these states through
coupling to nuclear spins and phonons. A second unique property of carbon
nanotubes is that the combination of valley freedom and electron-electron
interactions in one dimension strongly modifies their transport behaviour.
Interaction between electrons inside and outside a quantum dot is manifested in
SU(4) Kondo behavior and level renormalization. Interaction within a dot leads
to Wigner molecules and more complex correlated states.
This review takes an experimental perspective informed by recent advances in
theory. As well as the well-understood overall picture, we also state clearly
open questions for the field. These advances position nanotubes as a leading
system for the study of spin and valley physics in one dimension where
electronic disorder and hyperfine interaction can both be reduced to a very low
level.Comment: In press at Reviews of Modern Physics. 68 pages, 55 figure
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