27,256 research outputs found
High-voltage pulse generator developed for wide-gap spark chambers
Low-inductance, high-capacitance Marx pulse generator provides for minimization of internal inductance and suppression of external electromagnetic radiation. The spark gaps of the generator are enclosed in a pressurized nitrogen atmosphere which allows the charging voltage to be varied by changing the nitrogen pressure
Molecular orientation entanglement and temporal Bell-type inequalities
We detail and extend the results of [Milman {\it et al.}, Phys. Rev. Lett.
{\bf 99}, 130405 (2007)] on Bell-type inequalities based on correlations
between measurements of continuous observables performed on trapped molecular
systems. We show that for some observables with a continuous spectrum which is
bounded, one is able to construct non-locality tests sharing common properties
with those for two-level systems. The specific observable studied here is
molecular spatial orientation, and it can be experimentally measured for single
molecules, as required in our protocol. We also provide some useful general
properties of the derived inequalities and study their robustness to noise.
Finally, we detail possible experimental scenarii and analyze the role played
by different experimental parameters.Comment: 10 pages and 5 figure
Focal plane transport assembly for the HEAO-B X-ray telescope
The High Energy Astronomy Observatory - Mission B (HEAO-B), an earth orbiting X-ray telescope facility capable of locating and imaging celestial X-ray sources within one second of arc in the celestial sphere, is considered. The Focal Plane Transport Assembly (FPTA) is one of the basic structural elements of the three thousand pound HEAO-B experiment payload. The FPTA is a multifunctional assembly which supports seven imaging X-ray detectors circumferentially about a central shaft and accurately positions any particular one into the focus of a high resolution mirror assembly. A drive system, position sensor, rotary coupler, and detent alignment system, all an integral part of the rotatable portion which in turn is supported by main bearings to the stationary focal plane housing are described
Recommended from our members
Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess whether blue-light filtering spectacle lenses impart effects on visual function, provide protection to the macula, or both. We will also examine potential effects on the sleep-wake cycle
Polymorphism of the tumor necrosis factor beta gene in systemic lupus erythematosus
We investigated the Nco I restriction fragment
length polymorphism (RFLP) of the tumor necrosis
factor beta (TNFB) gene in 173 patients with systemic
lupus erythematosus (SLE), 192 unrelated
healthy controls, and eleven panel families, all of German
origin. The phenotype frequency of the TNFB*I
allele was significantly increased in patients compared
to controls (63.6% vs 47.1%, RR = 1.96, p <0.002).
The results of a two-point haplotype statistical analysis
between TNFB and HLA alleles show that there is linkage
disequilibrium between TNFB*I and HLA-A1,
Cw7, B8, DR3, DQ2, and C4A DE. The frequency of
TNFB*I was compared in SLE patients and controls in
the presence or absence of each of these alleles.
TNFB*I is increased in patients over controls only in
the presence of the mentioned alleles. Therefore, the
whole haplotypeA1, Cw7, B8, TNFB* I, C4A DE, DR3,
DQ2 is increased in patients and it cannot be determined
which of the genes carried by this haplotype is
responsible for the susceptibility to SLE. In addition,
two-locus associations were analyzed in 192 unrelated
healthy controls for TNFB and class I alleles typed by
serology, and for TNFB and class II alleles typed by
polymerase chain reaction/oligonucleotide probes. We
found positive linkage disequilibrium between
TNFB*I and the following alleles: HLA-A24, HLA-B8,
DRBI*0301, DRBI*ll04, DRBI*1302, DQAI*0501, DQBI*0201, DQBI*0604, and DPBI*OIO1. TNFB*2
is associated with HLA-B7, DRBI*1501, and
DQB I *0602
Oxygen-isotope effect on the superconducting gap in the cuprate superconductor Y_{1-x}Pr_xBa_2Cu_3O_{7-\delta}
The oxygen-isotope (^{16}O/^{18}O) effect (OIE) on the zero-temperature
superconducting energy gap \Delta_0 was studied for a series of
Y_{1-x}Pr_xBa_2Cu_3O_{7-\delta} samples (0.0\leq x\leq0.45). The OIE on
\Delta_0 was found to scale with the one on the superconducting transition
temperature. These experimental results are in quantitative agreement with
predictions from a polaronic model for cuprate high-temperature superconductors
and rule out approaches based on purely electronic mechanisms.Comment: 5 pages, 3 figure
Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO
We report the spontaneous formation of a plasma from a gas of cold Rydberg
molecules. Double-resonant laser excitation promotes nitric oxide, cooled to 1
K in a seeded supersonic molecular beam, to single Rydberg states extending as
deep as 80 cm below the lowest ionization threshold. The density of
excited molecules in the illuminated volume is as high as 1 x 10
cm. This population evolves to produce prompt free electrons and a
durable cold plasma of electrons and intact NO ions.Comment: 4 pages (two column) 3 figures; smaller figure files, corrected typo
Iconography in Medieval Spanish Literature
The masterpieces of medieval Spanish literature have come to be known and loved by Hispanists, and more recently by others throughout the world. But the brilliant illuminations with which the original manuscripts were illustrated have remained almost totally unknown on the shelves of the great European libraries. To redress this woeful neglect, two noted scholars here present a generous selection from this great visual treasury including many examples never before reproduced.
John E. Keller and Richard P. Kinkade have chosen five representative works, dating from the mid-thirteenth century to the late fifteenth, to illustrate the richness of early Spanish narrative art. Together, these five works encompass the entire range of narrative techniques and iconography to be found in medieval Spain, and reflect both foreign and native Spanish artistic tendencies. The authors’ analyses of the relation between verbalizations and visualizations will provide students of medieval art and literature a wealth of new information expanding our knowledge of this fascinating period. The beauty of many of the illuminations speaks for itself.
John E. Keller is professor of Spanish at the University of Kentucky.
Richard P. Kinkade is professor of Spanish and dean of humanities at the University of Arizona.https://uknowledge.uky.edu/upk_spanish_literature/1022/thumbnail.jp
Insights into Regolith Dynamics from the Irradiation Record Preserved in Hayabusa Samples
The rates of space weathering processes are poorly constrained for asteroid surfaces, with recent estimates ranging over 5 orders of magnitude. The return of the first surface samples from a space-weathered asteroid by the Hayabusa mission and their laboratory analysis provides "ground truth" to anchor the timescales for space weathering. We determine the rates of space weathering on Itokawa by measuring solar flare track densities and the widths of solar wind damaged rims on grains. These measurements are made possible through novel focused ion beam (FIB) sample preparation methods
- …