scholarly journals Quantification of Uncoupled Spin Domains in Spin-Abundant Disordered Solids

2020 ◽  
Vol 21 (11) ◽  
pp. 3938
Author(s):  
Brennan J. Walder ◽  
Todd M. Alam
Keyword(s):  
Solid State Nmr ◽  
Single Pulse ◽  
Graphitic Carbon ◽  
Signal Averaging ◽  
Disordered Solids ◽  
Direct Fluorination ◽  
Long Duration ◽  
Pulse Experiment ◽  
Nmr Signals ◽  
Better Than

Materials often contain minor heterogeneous phases that are difficult to characterize yet nonetheless significantly influence important properties. Here we describe a solid-state NMR strategy for quantifying minor heterogenous sample regions containing dilute, essentially uncoupled nuclei in materials where the remaining nuclei experience heteronuclear dipolar couplings. NMR signals from the coupled nuclei are dephased while NMR signals from the uncoupled nuclei can be amplified by one or two orders of magnitude using Carr-Meiboom-Purcell-Gill (CPMG) acquisition. The signal amplification by CPMG can be estimated allowing the concentration of the uncoupled spin regions to be determined even when direct observation of the uncoupled spin NMR signal in a single pulse experiment would require an impractically long duration of signal averaging. We use this method to quantify residual graphitic carbon using 13 C CPMG NMR in poly(carbon monofluoride) samples synthesized by direct fluorination of carbon from various sources. Our detection limit for graphitic carbon in these materials is better than 0.05 mol%. The accuracy of the method is discussed and comparisons to other methods are drawn.

scholarly journals A large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research

2018 ◽  
Vol 11 (8) ◽  
pp. 4757-4762 ◽  
Author(s):  
Friedhelm Olschewski ◽  
Christian Monte ◽  
Albert Adibekyan ◽  
Max Reiniger ◽  
Berndt Gutschwager ◽  
...  
Keyword(s):  
Temperature Scale ◽  
Environmental Research ◽  
Large Area ◽  
Atmospheric Measurements ◽  
Calibration Source ◽  
Aperture Diameter ◽  
International Temperature Scale ◽  
International Temperature ◽  
Long Duration ◽  
Better Than

Abstract. The deployment of the imaging Fourier Transform Spectrometer GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on board a long-duration balloon for stratospheric research requires a blackbody for in-flight calibration in order to provide traceability to the International Temperature Scale (ITS-90) to ensure comparability with the results of other experiments and over time. GLORIA, which has been deployed onboard various research aircraft such as the Russian M55 Geophysica or the German HALO in the past, shall also be used for detailed atmospheric measurements in the stratosphere up to 40 km altitude. The instrument uses a two-dimensional detector array and an imaging optics with a large aperture diameter of 36 mm and an opening angle of 4.07∘ × 4.07∘ for infrared limb observations. To overfill the field of view (FOV) of the instrument, a large-area blackbody radiation sources (125 mm × 125 mm) is required for in-flight calibration. In order to meet the requirements regarding the scientific goals of the GLORIA missions, the radiance temperature of the blackbody calibration source has to be determined to better than 100 mK and the spatial temperature uniformity shall be better than 150 mK. As electrical resources on board a stratospheric balloon are very limited, the latent heat of the phase change of a eutectic material is utilized for temperature stabilization of the calibration source, such that the blackbody has a constant temperature of about −32 ∘C corresponding to a typical temperature observed in the stratosphere. The Institute for Atmospheric and Environmental Research at the University of Wuppertal designed and manufactured a prototype of the large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research. This newly developed calibration source was tested under lab conditions as well as in a climatic and environmental test chamber in order to verify its performance especially under flight conditions. At the PTB (Physikalisch-Technische Bundesanstalt), the German national metrology institute, the spatial radiance distribution of the blackbody was determined and traceability to the International Temperature Scale (ITS-90) has been assured. In this paper the design and performance of the balloon-borne blackbody (BBB) is presented.

scholarly journals Consolidation of reward memory during sleep does not require dopaminergic activation

2019 ◽  
Author(s):  
M Alizadeh Asfestani ◽  
V Brechtmann ◽  
J Santiago ◽  
J Born ◽  
GB Feld
Keyword(s):  
Learning Task ◽  
Reward Learning ◽  
Nocturnal Sleep ◽  
Double Blind ◽  
Dopaminergic Neurotransmission ◽  
Long Duration ◽  
Differential Retention ◽  
Better Than ◽  
Dopaminergic Activation

AbstractSleep enhances memories, especially, if they are related to future rewards. Although dopamine has been shown to be a key determinant during reward learning, the role of dopaminergic neurotransmission for amplifying reward-related memories during sleep remains unclear. In the present study, we scrutinize the idea that dopamine is needed for the preferential consolidation of rewarded information. We blocked dopaminergic neurotransmission, thereby aiming to wipe out preferential sleep-dependent consolidation of high over low rewarded memories during sleep. Following a double-blind, balanced, crossover design 20 young healthy men received the dopamine d2-like receptor blocker Sulpiride (800 mg) or placebo, after learning a Motivated Learning Task. The task required participants to memorize 80 highly and 80 lowly rewarded pictures. Half of them were presented for a short (750 ms) and a long duration (1500 ms), respectively, which enabled to dissociate effects of reward on sleep-associated consolidation from those of mere encoding depth. Retrieval was tested after a retention interval of 20 h that included 8 h of nocturnal sleep. As expected, at retrieval, highly rewarded memories were remembered better than lowly rewarded memories, under placebo. However, there was no evidence for an effect of blocking dopaminergic neurotransmission with Sulpiride during sleep on this differential retention of rewarded information. This result indicates that dopaminergic activation is not required for the preferential consolidation of reward-associated memory. Rather it appears that dopaminergic activation only tags such memories at encoding for intensified reprocessing during sleep.

scholarly journals Long-duration nano-second single pulse lasers for observation of spectra from bulk liquids at high hydrostatic pressures

2014 ◽  
Vol 97 ◽  
pp. 7-12 ◽  
Author(s):  
Blair Thornton ◽  
Tetsuo Sakka ◽  
Tatsuya Masamura ◽  
Ayaka Tamura ◽  
Tomoko Takahashi ◽  
...  
Keyword(s):  
Single Pulse ◽  
Long Duration ◽  
High Hydrostatic Pressures

RESULTS FROM THE ANITA EXPERIMENT

2007 ◽  
Vol 22 (30) ◽  
pp. 2237-2246 ◽  
Author(s):  
◽  
ANDREA SILVESTRI ◽  
S. W. BARWICK ◽  
J. J. BEATTY ◽  
D. Z. BESSON ◽  
...  
Keyword(s):  
Neutrino Flux ◽  
High Energy ◽  
Long Duration ◽  
Order Of Magnitude ◽  
Successful Launch ◽  
Balloon Experiment ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Prototype Instrument ◽  
Better Than

The ANtarctic Impulse Transient Antenna (ANITA) is the first long-duration balloon experiment designed to search and measure the flux of Greisen–Zapsepin–Kuzmin (GZK) neutrinos. We present new limits on neutrinos fluxes of astronomical origin from data collected with the successful launch of a 2-antenna prototype instrument, called ANITA-lite, that circled the Antarctic continent for 18.4 days in January 2004. We performed a search for Ultra-High-Energy (UHE) neutrinos with energies above 3 × 1018 eV . No excess events above the background expectation were observed and a neutrino flux following E-2 spectrum for all neutrino flavors, is limited to [Formula: see text] for 1018.5 eV < Eν < 1023.5 eV at 90% confidence level. The launch of ANITA is scheduled for December 2006. Looking beyond ANITA, we describe a new idea, called ARIANNA (Antarctic Ross Iceshelf ANtenna Neutrino Array), to increase the sensitivity for GZK neutrinos by one order of magnitude better than ANITA.

Measurement of the Sensitivity and Photometric Accuracy of FT-IR Spectrometers

2000 ◽  
Vol 54 (8) ◽  
pp. 1192-1202 ◽  
Author(s):  
Bryan T. Bowie ◽  
Peter R. Griffiths
Keyword(s):  
Fourier Transform ◽  
Standard Deviation ◽  
Thick Film ◽  
Polyethylene Terephthalate ◽  
Noise Level ◽  
Fourier Transform Infrared ◽  
Signal Averaging ◽  
Ft Ir ◽  
Better Than

A method has been developed to investigate the sensitivity and photometric accuracy of a Fourier transform infrared (FT-IR) spectrometer by statistically analyzing a set of spectra of a 75 μm thick film of polyethylene terephthalate (PET). These tests were applied to three commercial FT-IR spectrometers. Although the photometric accuracy of all three instruments was generally better than 0.1%, small artifacts that could not be removed by signal averaging were often observed where strong bands should have a transmittance of less than 0.01%. Binding of the moving mirror of one of the spectrometers appeared to degrade its performance. When the standard deviation of the noise on 100% lines was calculated in the conventional way, none of the instruments gave efficient signal averaging after 25 scans had been coadded, because of small slopes in the baseline. By calculation of the noise level by successive difference, signal averaging was improved, but even with this approach the noise level on one of the instruments did not decrease after 100 scans had been averaged.

scholarly journals A large-area blackbody for inflight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research

2018 ◽  
Author(s):  
Friedhelm Olschewski ◽  
Christian Monte ◽  
Albert Adibekyan ◽  
Max Reiniger ◽  
Berndt Gutschwager ◽  
...  
Keyword(s):  
Temperature Scale ◽  
Environmental Research ◽  
Large Area ◽  
Atmospheric Measurements ◽  
Calibration Source ◽  
Aperture Diameter ◽  
International Temperature Scale ◽  
International Temperature ◽  
Long Duration ◽  
Better Than

Abstract. The deployment of the imaging Fourier Transform Spectrometer GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on board a long-duration balloon for stratospheric research requires a blackbody for inflight calibration in order to provide traceability to the International Temperature Scale (ITS-90) to ensure comparability with the results of other experiments and over time. GLORIA, which has been deployed onboard various research aircraft such as the Russian M55 Geophysica or the German HALO in the past, shall also be used for detailed atmospheric measurements in the stratosphere up to 40 km altitude. The instrument uses a two-dimensional detector array and an imaging optics with a large aperture diameter of 36 mm and an opening angle of 4.07° × 4.07° for infrared limb observations. To overfill the field-of-view (FOV) of the instrument, a large-area blackbody radiation sources (125 mm × 125 mm) is required for inflight calibration. In order to meet the requirements regarding the scientific goals of the GLORIA missions, the radiance temperature of the blackbody calibration source has to be determined to better than 100 mK and the spatial uniformity shall be better than 100 mK. Since electrical resources onboard a stratospheric balloon are very limited, the latent heat of the phase change of a eutectic material is utilized for temperature stabilization of the calibration source, such that the blackbody has a constant temperature of about −32 °C corresponding to a typical temperature observed in the stratosphere. The Institute for Atmospheric and Environmental Research at the University ofWuppertal designed and manufactured a prototype of the large-area blackbody for inflight calibration of an infrared interferometer deployed onboard a long-duration balloon for stratospheric research. This newly developed calibration source was tested under lab conditions as well as in a climatic and environmental test chamber in order to verify its performance especially under flight conditions. At PTB (Physikalisch-Technische Bundesanstalt), the German national metrology institute the spectral and spatial radiance distribution of the blackbody was determined and traceability to the International Temperature Scale (ITS-90) has been assured. In this paper the design and performance of the Balloon-borne BlackBody (BBB) is presented.

scholarly journals Many-valued logic and sequence arguments in value theory

Synthese ◽  
2021 ◽  
Author(s):  
Simon Knutsson
Keyword(s):  
Classical Logic ◽  
Value Theory ◽  
Logical Framework ◽  
Initial Value ◽  
Long Duration ◽  
Almost All ◽  
Better Than

AbstractSome find it plausible that a sufficiently long duration of torture is worse than any duration of mild headaches. Similarly, it has been claimed that a million humans living great lives is better than any number of worm-like creatures feeling a few seconds of pleasure each. Some have related bad things to good things along the same lines. For example, one may hold that a future in which a sufficient number of beings experience a lifetime of torture is bad, regardless of what else that future contains, while minor bad things, such as slight unpleasantness, can always be counterbalanced by enough good things. Among the most common objections to such ideas are sequence arguments. But sequence arguments are usually formulated in classical logic. One might therefore wonder if they work if we instead adopt many-valued logic. I show that, in a common many-valued logical framework, the answer depends on which versions of transitivity are used as premises. We get valid sequence arguments if we grant any of several strong forms of transitivity of ‘is at least as bad as’ and a notion of completeness. Other, weaker forms of transitivity lead to invalid sequence arguments. The plausibility of the premises is largely set aside here, but I tentatively note that almost all of the forms of transitivity that lead to valid sequence arguments seem intuitively problematic. Still, a few moderately strong forms of transitivity that might be acceptable lead to valid sequence arguments, although weaker statements of the initial value claims avoid these arguments at least to some extent.

Built-In Potentials Via Electroabsorption Measurements in a-Si:H p-i-n Solar Cells: a Critical Assessment

1994 ◽  
Vol 336 ◽  
Author(s):  
Qi Wang ◽  
E. A. Schiff ◽  
Steven S. Hegedus
Keyword(s):  
Solar Cells ◽  
Wavelength Dependence ◽  
Laser Wavelength ◽  
Critical Assessment ◽  
Signal Averaging ◽  
External Bias ◽  
Linear Fit ◽  
Better Than ◽  
Averaging Techniques ◽  
Good Agreement

ABSTRACTWe have measured electroabsorption (EA) in a-Si:H p-i-n solar cells in order to estimate their built-in potentials Vbi. This Method was pioneered by the Osaka University group; in simple cases Vbi is identified with a parameter V0 obtained by a simple linear fit to the dependence of EA on external bias voltage. Using signal averaging techniques we are able to Measure V0 with a reproducibility of better than 2%. In one sample from the Institute of Energy Conversion with an a-SiC:H p+ layer we estimate Vbj = 0.97 ± 0.06 V, which is in good agreement with previous JVT Measurement. The reason that the error estimate is larger than the reproducibility error is the presence of several small effects not accounted for by the original EA theory: in particular V0 depends slightly on the laser wavelength. We attribute these effects to the small portion of Vbi dropped in the a-SiC:Hp+ layer, which has a different electroabsorption than a-Si:H. We discuss models for the wavelength dependence.

scholarly journals Effect of aluminum and sodium on the sorption of water and methanol in microporous MFI-type zeolites and mesoporous SBA-15 materials

Adsorption ◽  
2020 ◽  
Author(s):  
Zheng Li ◽  
Carolin Rieg ◽  
Ann-Katrin Beurer ◽  
Michael Benz ◽  
Johannes Bender ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Acid Sites ◽  
Mas Nmr ◽  
Nmr Studies ◽  
Oh Groups ◽  
Adsorption Sites ◽  
Low Field ◽  
Strong Adsorption ◽  
Nmr Signals

Abstract The interaction and nature of surface sites for water and methanol sorption on MFI-type zeolites and mesoporous SBA-15 were investigated by solid-state NMR spectroscopy and correlated with the desorption enthalpies determined via TGA/DSC. For siliceous Silicalite-1, 29Si CPMAS NMR studies support stronger methanol than water interactions with SiOH groups of Q3-type. On siliceous SBA-15, SiOH groups of Q2-type are accompanied by an enhanced hydrophilicity. In aluminum-containing Na-ZSM-5, Na+ cations are strong adsorption sites for water and methanol as evidenced by 23Na MAS NMR in agreement with high desorption enthalpies of ΔH = 66–74 kJ/mol. Solid-state NMR of aluminum-containing Na-[Al]SBA-15, in contrast, has shown negligible water and methanol interactions with sodium and aluminum. Desorption enthalpies of ΔH = 44–60 kJ/mol hint at adsorption sites consisting of SiOH groups influenced by distant framework aluminum. On H-ZSM-5, Brønsted acidic OH groups are strong adsorption sites as indicated by partial protonation of water and methanol causing low-field shifts of their 1H MAS NMR signals and enhanced desorption enthalpies. Due to the small number of Brønsted acid sites in aluminum-containing H-[Al]SBA-15, water and methanol adsorption on this material is suggested to mainly occur at SiOH groups with distant framework aluminum species, as in the case of Na-[Al]SBA-15.

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