16,132 research outputs found
The Skyrme Model piNN Form Factor and the Sea Quark Distribution of the Nucleon
We calculate the sea quark distribution of the nucleon in a meson cloud
model. The novel feature of our calculation is the implementation of a special
piNN form factor recently obtained by Holzwarth and Machleidt. This form factor
is hard for small and soft for large momentum transfers. We show that this
feature leads to a substantial improvement.Comment: 9 pages, 5 figures; v2: some typos corrected, including eq. (9
Simple circuit performs binary addition and subtraction
Ripple adder reduces the number of logic circuits required to preform binary addition and subtraction. The adder uses dual input and delayed output flip-flops in one register. The contents of this register are summed with those of a standard register through conventional AND/gates
Ripple add and ripple subtract binary counters Patent
Logic circuit to ripple add and subtract binary counters for spaceborne computer
Application of PN and avalanche silicon photodiodes to low-level optical
New approaches to the discovery of other planetary systems require very sensitive and stable detection techniques in order to succeed. Two methods in particular, the astrometric and the photometric methods, require this. To begin understanding the problems and limitations of solid state detectors regarding this application, preliminary experiments were performed at the National Bureau of Standards and a low light level detector characterization facility was built. This facility is briefly described, and the results of tests conducted in it are outlined. A breadboard photometer that was used to obtain stellar brightness ratio precision data is described. The design principles of PN and avalanche silicon photodiodes based on low light level measuring circuits are discussed
Polarized antiquark flavor asymmetry: Pauli blocking vs. the pion cloud
The flavor asymmetry of the unpolarized antiquark distributions in the
proton, dbar(x) - ubar(x) > 0, can qualitatively be explained either by Pauli
blocking by the valence quarks, or as an effect of the pion cloud of the
nucleon. In contrast, predictions for the polarized asymmetry Delta_ubar(x) -
Delta_dbar(x) based on rho meson contributions disagree even in sign with the
Pauli blocking picture. We show that in the meson cloud picture a large
positive Delta_ubar(x) - Delta_dbar(x) is obtained from pi-N - sigma-N
interference-type contributions, as suggested by chiral symmetry. This effect
restores the equivalence of the 'quark' and 'meson' descriptions also in the
polarized case.Comment: 4 pages, revtex, 3 eps figure
Integral lift engine preliminary design
A preliminary mechanical design of a complete lift fan engine system is reported. A description of the lift fan engine, layout drawings of the components and complete engine, and a discussion of the design analyses and results are presented. The design features and areas of analysis include fan and compressor rotor blades of composite construction, a combustor folded over the compressor, relatively high-temperature blades in the high-pressure turbine, the first stage of the low-pressure turbine used for bearing support and ducting of lubricant to the bearings, a complete lubrication system, critical speeds of the shafting, and vibration and flutter of the blading
Research and development in CdS photovoltaic cells Third quarterly report, 29 Dec. 1965 - 29 Mar. 1966
Barrier formation studies of copper sulfide and cadmium sulfide in photovoltaic cell
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