29,545 research outputs found
Monte Carlo calculations of energy depositions and radiation transport. Volume 1 - Validation of COHORT codes
Monte Carlo codes for IBM 7090 digital computer to calculate radiation heating in propellant tanks, and radiation environment about nuclear rocket stag
X-ray photoelectron spectroscopy investigation of the mixed anion GaSb/InAs heterointerface
X-ray photoelectron spectroscopy has been used to measure levels of anion cross-incorporation and to study interface formation for the mixed anion GaSb/lnAs heterojunction. Anion
cross-incorporation was measured in 20 Å thick GaSb layers grown on lnAs, and 20 Å thick InAs layers grown on GaSb for cracked and uncracked sources. It was found that significantly
less anion cross-incorporation occurs in structures grown with cracked sources. Interface formation was investigated by studying Sb soaks of InAs surfaces and As soaks of GaSb surfaces
as a function of cracker power and soak time. Exchange of the group V surface atoms was found to be an increasing function of both cracker power and soak time. We find that further
optimization of current growth parameters may be possible by modifying the soak time used at interfaces
Detection of hidden mineral deposits by airborne spectral analysis of forest canopies
Data from field surveys and biogeochemical tests conducted in Maine, Montana, and Washington strongly correlate with results obtained using high resolution airborne spectroradiometer which detects an anomalous spectral waveform that appears definitely associated with sulfide mineralization. The spectral region most affected by mineral stress is between 550 nm and 750 nm. Spectral variations observed in the field occur on the wings of the red chlorophyll band centered at about 690 nm. The metal-stress-induced variations on the absorption band wing are most successfully resolved in the high spectral resolution field data using a waveform analysis technique. The development of chlorophyll pigments was retarded in greenhouse plants doped with copper and zinc in the laboratory. The lowered chlorophyll production resulted in changes on the wings of the chlorophyll bands of reflectance spectra of the plants. The airborne spectroradiometer system and waveform analysis remains the most sensitive technique for biogeochemical surveys
‘Multi-directional management’: Exploring the challenges of performance in the World Class Programme environment
Driven by the ever-increasing intensity of Olympic competition and the ‘no compromise – no stone unturned’ requirements frequently addressed by HM Government and its main agency, UK Sport, a change in culture across Olympic team landscapes is a common occurrence. With a focus on process, this paper presents reflections from eight current or recently serving UK Olympic sport Performance Directors on their experiences of creating and disseminating their vision for their sport, a vital initial activity of the change initiative. To facilitate a broad overview of this construct, reflections are structured around the vision’s characteristics and foundations, how it is delivered to key stakeholder groups, how it is influenced by these groups, the qualities required to ensure its longevity and its limitations. Emerging from these perceptions, the creation and maintenance of a shared team vision was portrayed as a highly dynamic task requiring the active management of a number of key internal and external stakeholders. Furthermore, the application of ‘dark’ traits and context-specific expertise were considered critical attributes for the activity’s success. Finally, recent calls for research to elucidate the wider culture optimisation process are reinforced
Study of interface asymmetry in InAs–GaSb heterojunctions
We present reflection high energy electron diffraction, secondary ion mass spectroscopy, scanning tunneling microscopy and x‐ray photoelectron spectroscopy studies of the abruptness of InAs–GaSb interfaces. We find that the interface abruptness depends on growth order: InAs grown on GaSb is extended, while GaSb grown on InAs is more abrupt. We first present observations of the interfacial asymmetry, including measurements of band alignments as a function of growth order. We then examine more detailed studies of the InAs–GaSb interface to determine the mechanisms causing the extended interface. Our results show that Sb incorporation into the InAs overlayer and As exchange for Sb in the GaSb underlayer are the most likely causes of the interfacial asymmetry
QCD Factorization for Semi-Inclusive Deep-Inelastic Scattering at Low Transverse Momentum
We demonstrate a factorization formula for semi-inclusive deep-inelastic
scattering with hadrons in the current fragmentation region detected at low
transverse momentum. To facilitate the factorization, we introduce the
transverse-momentum dependent parton distributions and fragmentation functions
with gauge links slightly off the light-cone, and with soft-gluon radiations
subtracted. We verify the factorization to one-loop order in perturbative
quantum chromodynamics and argue that it is valid to all orders in perturbation
theory.Comment: 28 pages, figures include
Scanning tunneling microscopy of lnAs/GaSb superlattices: Subbands, interface roughness, and interface asymmetry
Scanning tunneling microscopy and spectroscopy is used to characterize InAs/GaSb superlattices, grown by molecular-beam epitaxy. Roughness at the interfaces between InAs and GaSb layers is directly observed in the images, and a quantitative spectrum of this roughness is obtained. Electron subbands in the InAs layers are resolved in spectroscopy. Asymmetry between the interfaces of InAs grown on GaSb compared with GaSb grown on In As is seen in voltage-dependent imaging. Detailed
spectroscopic study of the interfaces reveals some subtle differences between the two in terms of their valence-band onsets and conduction-band state density. These differences are interpreted in a model in which the GaSb on InAs interface has an abrupt InSb-like structure, but at the InAs on GaSb interface some Sb grading occurs into the InAs overlayer
Sublattice Asymmetric Reductions of Spin Values on Stacked Triangular Lattice Antiferromagnet CsCoBr
We study the reductions of spin values of the ground state on a stacked
triangular antiferromagnet using the spin-wave approach. We find that the spin
reductions have sublattice asymmetry due to the cancellation of the molecular
field. The sublattice asymmetry qualitatively analyzes the NMR results of
CsCoBr.Comment: 5pages, 5figure
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