Energy spectra due to the intrinsic radiation of LYSO/LSO scintillators for a wide range of crystal sizes

2021 ◽  
Author(s):  
Dalia Yvette Domínguez‐Jiménez ◽  
Héctor Alva‐Sánchez
Keyword(s):  
Energy Spectra ◽  
Wide Range ◽  
Intrinsic Radiation

scholarly journals Dependence of Model Energy Spectra on Vertical Resolution

2016 ◽  
Vol 144 (4) ◽  
pp. 1407-1421 ◽  
Author(s):  
Michael L. Waite
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Vertical Mixing ◽  
Energy Spectra ◽  
Small Scale ◽  
Rossby Number ◽  
Vertical Resolution ◽  
Wide Range ◽  
Qualitative Shape ◽  
Vertical Grid

Abstract Many high-resolution atmospheric models can reproduce the qualitative shape of the atmospheric kinetic energy spectrum, which has a power-law slope of −3 at large horizontal scales that shallows to approximately −5/3 in the mesoscale. This paper investigates the possible dependence of model energy spectra on the vertical grid resolution. Idealized simulations forced by relaxation to a baroclinically unstable jet are performed for a wide range of vertical grid spacings Δz. Energy spectra are converged for Δz 200 m but are very sensitive to resolution with 500 m ≤ Δz ≤ 2 km. The nature of this sensitivity depends on the vertical mixing scheme. With no vertical mixing or with weak, stability-dependent mixing, the mesoscale spectra are artificially amplified by low resolution: they are shallower and extend to larger scales than in the converged simulations. By contrast, vertical hyperviscosity with fixed grid-scale damping rate has the opposite effect: underresolved spectra are spuriously steepened. High-resolution spectra are converged except for the stability-dependent mixing case, which are damped by excessive mixing due to enhanced shear over a wide range of horizontal scales. It is shown that converged spectra require resolution of all vertical scales associated with the resolved horizontal structures: these include quasigeostrophic scales for large-scale motions with small Rossby number and the buoyancy scale for small-scale motions at large Rossby number. It is speculated that some model energy spectra may be contaminated by low vertical resolution, and it is recommended that vertical-resolution sensitivity tests always be performed.

Hot-wire spatial resolution issues in wall-bounded turbulence

2009 ◽  
Vol 635 ◽  
pp. 103-136 ◽  
Author(s):  
N. HUTCHINS ◽  
T. B. NICKELS ◽  
I. MARUSIC ◽  
M. S. CHONG
Keyword(s):  
Reynolds Number ◽  
Boundary Layers ◽  
Spatial Resolution ◽  
Reynolds Numbers ◽  
Energy Spectra ◽  
Small Scale ◽  
Wire Length ◽  
Hot Wire ◽  
Wide Range ◽  
Near Wall

Careful reassessment of new and pre-existing data shows that recorded scatter in the hot-wire-measured near-wall peak in viscous-scaled streamwise turbulence intensity is due in large part to the simultaneous competing effects of the Reynolds number and viscous-scaled wire length l+. An empirical expression is given to account for these effects. These competing factors can explain much of the disparity in existing literature, in particular explaining how previous studies have incorrectly concluded that the inner-scaled near-wall peak is independent of the Reynolds number. We also investigate the appearance of the so-called outer peak in the broadband streamwise intensity, found by some researchers to occur within the log region of high-Reynolds-number boundary layers. We show that the ‘outer peak’ is consistent with the attenuation of small scales due to large l+. For turbulent boundary layers, in the absence of spatial resolution problems, there is no outer peak up to the Reynolds numbers investigated here (Reτ = 18830). Beyond these Reynolds numbers – and for internal geometries – the existence of such peaks remains open to debate. Fully mapped energy spectra, obtained with a range of l+, are used to demonstrate this phenomenon. We also establish the basis for a ‘maximum flow frequency’, a minimum time scale that the full experimental system must be capable of resolving, in order to ensure that the energetic scales are not attenuated. It is shown that where this criterion is not met (in this instance due to insufficient anemometer/probe response), an outer peak can be reproduced in the streamwise intensity even in the absence of spatial resolution problems. It is also shown that attenuation due to wire length can erode the region of the streamwise energy spectra in which we would normally expect to see kx−1 scaling. In doing so, we are able to rationalize much of the disparity in pre-existing literature over the kx−1 region of self-similarity. Not surprisingly, the attenuated spectra also indicate that Kolmogorov-scaled spectra are subject to substantial errors due to wire spatial resolution issues. These errors persist to wavelengths far beyond those which we might otherwise assume from simple isotropic assumptions of small-scale motions. The effects of hot-wire length-to-diameter ratio (l/d) are also briefly investigated. For the moderate wire Reynolds numbers investigated here, reducing l/d from 200 to 100 has a detrimental effect on measured turbulent fluctuations at a wide range of energetic scales, affecting both the broadband intensity and the energy spectra.

scholarly journals Nuclear disintegrations produced by cosmic rays

1949 ◽  
Vol 196 (1046) ◽  
pp. 325-343 ◽  
Keyword(s):  
Cosmic Radiation ◽  
High Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Wide Range ◽  
High Energy Tail ◽  
Energy And Angular Distributions ◽  
Photographic Emulsions ◽  
Α Particles

Measurements have been made on the energy and angular distributions of the charged particles from disintegration ‘stars’ produced in the silver and bromine nuclei of photographic emulsions exposed to cosmic radiation. The observations extended over a wide range of excitation energies (100 to 700 MeV). The energy spectra and angular distributions of the protons can be explained in all cases by simple evaporation theory. This energy distribution shows also a high-energy tail consisting of direct knock-on protons and slow mesons. At high excitation energies the α-particles exhibit collimation effects which are probably due to localized ‘boiling’ or a form of fission.

In vivo stability of protein coatings on poly lactic co glycolic nanoparticles

MRS Advances ◽  
2016 ◽  
Vol 1 (56) ◽  
pp. 3767-3773 ◽  
Author(s):  
Jordi Llop ◽  
Marco Marradi ◽  
Pengfei Jiang ◽  
Vanessa Gómez-Vallejo ◽  
Zuriñe Baz ◽  
...  
Keyword(s):  
Electrophilic Substitution ◽  
Single Photon ◽  
Photon Emission ◽  
Degradation Process ◽  
Energy Spectra ◽  
Single Photon Emission ◽  
Computerised Tomography ◽  
The Core ◽  
Wide Range

ABSTRACTSubmicron-sized poly(lactide-co-glycolide) nanoparticles (PLGA-NPs) stabilised with bovine serum albumin (BSA) are dual radiolabelled using gamma emitters with different energy spectra incorporated into the core and coating. PLGA core is labelled by encapsulation of 111In-doped iron oxide NPs inside PLGA-NPs during NP preparation, while the BSA coating is labelled by electrophilic substitution using 125I. After intravenous administration into rats, energy-discriminant single-photon emission computerised tomography (SPECT) resolved each radioisotope independently. Imaging revealed different fates for the core and coating, with a fraction of the two radionuclides co-localising in the liver and lungs for long periods of time after administration, suggesting that NPs are stable in these organs. The general methodology reported here represents an excellent alternative for visualising the degradation process of multi-labelled NPs in vivo and can be extended to a wide range of engineered NPs.

scholarly journals One-Electron Energy Spectra of Heavy Highly Charged Quasimolecules: Finite-Basis-Set Approach

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 44
Author(s):  
Artem A. Kotov ◽  
Dmitry A. Glazov ◽  
Vladimir M. Shabaev ◽  
Günter Plunien
Keyword(s):  
Bound State ◽  
Finite Basis ◽  
Basis Set ◽  
Energy Spectra ◽  
Axially Symmetric ◽  
Wide Range ◽  
Monopole Approximation ◽  
Internuclear Distances ◽  
Bound State Qed ◽  
Symmetric Systems

The generalized dual-kinetic-balance approach for axially symmetric systems is employed to solve the two-center Dirac problem. The spectra of one-electron homonuclear quasimolecules are calculated and compared with the previous calculations. The analysis of the monopole approximation with two different choices of the origin is performed. Special attention is paid to the lead and xenon dimers, Pb82+–Pb82+–e− and Xe54+–Xe54+–e−, where the energies of the ground and several excited σ-states are presented in the wide range of internuclear distances. The developed method provides the quasicomplete finite basis set and allows for the construction of perturbation theory, including within the bound-state QED.

scholarly journals Lognormality in Turbulence Energy Spectra

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 669
Author(s):  
Taewoo Lee
Keyword(s):  
Reynolds Number ◽  
Distribution Function ◽  
Maximum Entropy ◽  
Energy Content ◽  
Energy Spectra ◽  
Turbulence Energy ◽  
Zero Energy ◽  
Length Scales ◽  
Physical Constraints ◽  
Wide Range

The maximum entropy principle states that the energy distribution will tend toward a state of maximum entropy under the physical constraints, such as the zero energy at the boundaries and a fixed total energy content. For the turbulence energy spectra, a distribution function that maximizes entropy with these physical constraints is a lognormal function due to its asymmetrical descent to zero energy at the boundary lengths scales. This distribution function agrees quite well with the experimental data over a wide range of energy and length scales. For turbulent flows, this approach is effective since the energy and length scales are determined primarily by the Reynolds number. The total turbulence kinetic energy will set the height of the distribution, while the ratio of length scales will determine the width. This makes it possible to reconstruct the power spectra using the Reynolds number as a parameter.

scholarly journals Pairing and (9/2)n configuration in nuclei in the 208Pb region

2018 ◽  
Vol 177 ◽  
pp. 03004
Author(s):  
M. Stepanov ◽  
L. Imasheva ◽  
B. Ishkhanov ◽  
T. Tretyakova
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Ground State ◽  
Exotic Nuclei ◽  
Low Energy ◽  
Energy Spectra ◽  
Pairing Energy ◽  
Multiplet Splitting ◽  
Wide Range ◽  
Nuclear Masses

Excited states in low-energy spectra in nuclei near 208Pb are considered. The pure (j = 9/2)n configuration approximation with delta-force is used for ground state multiplet calculations. The multiplet splitting is determined by the pairing energy, which can be defined from the even-odd straggering of the nuclear masses. For the configurations with more than two valence nucleons, the seniority scheme is used. The results of the calculations agree with the experimental data for both stable and exotic nuclei within 0.06-6.16%. Due to simplicity and absence of the fitted parameters, the model can be easily applied for studies of nature of the excited states in a wide range of nuclei.

scholarly journals Energy Spectra of Atmospheric Turbulence for Calculating Cn2 Parameter. I. Maidanak and Suffa Observatories in Uzbekistan

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1614
Author(s):  
Artem Yu. Shikhovtsev ◽  
Pavel G. Kovadlo ◽  
Evgeniy A. Kopylov ◽  
Mansur A. Ibrahimov ◽  
Shuhrat A. Ehgamberdiev ◽  
...  
Keyword(s):  
Refractive Index ◽  
Atmospheric Turbulence ◽  
Baroclinic Instability ◽  
Structure Constant ◽  
Index Structure ◽  
Energy Spectra ◽  
Atmospheric Conditions ◽  
Astronomical Observations ◽  
Turbulence Spectra ◽  
Wide Range

Knowledge of the turbulence spectra is of interest for describing atmospheric conditions as applied to astronomical observations. This article discusses the deformations of the turbulence spectra with heights in a wide range of scales at the sites of the Maidanak and Suffa observatories. It is shown that the energy of baroclinic instability is high at the sites of these observatories and should be taken into account in the calculations of the refractive index structure constant Cn2.

LATTICE DYNAMICS OF THE BINARY APERIODIC CHAINS OF ATOMS II: MULTIFRACTALITY OF PHONON SPECTRA

1995 ◽  
Vol 09 (12) ◽  
pp. 1453-1474 ◽  
Author(s):  
WŁODZIMIERZ SALEJDA
Keyword(s):  
Lattice Dynamics ◽  
Energy Spectra ◽  
Legendre Transformation ◽  
Model Parameters ◽  
Local Scaling ◽  
Multifractal Formalism ◽  
Phonon Spectra ◽  
Wide Range ◽  
Multifractal Spectra ◽  
Density Of Phonon States

The curdling of the phonon eigenvalues (PEV) on energy spectra of the binary generalized Fibonacci and non-Fibonaccian chains of atoms are numerically studied. A multifractal formalism based upon a new numerically efficient Legendre transformation from (q, τ) to (α, f) variables is proposed. The multifractal spectra of the normalized integrated density of phonon states (NIDOPS) for aperiodic chains of atoms are calculated in a wide range of model parameters. It is found out that the interval (α min , α max ) of magnitudes of the exponent α, determining the local scaling of the NIDOPS, shows a considerable shift to smaller values. This tendency is most pronounced for the NIDOPS of the so-called copper-mean, nickel-mean, structural circle and Rudin-Shapiro chain, where 0<α min <0.1. It is verified numerically that this effect is a manifestation of a strong curdling of PEV which take place in optical regions of the phonon spectra.

scholarly journals One-electron Energy Spectra of Heavy Highly Charged Quasimolecules

2021 ◽  
Author(s):  
Artem A. Kotov ◽  
Dmitry A. Glazov ◽  
Vladimir Shabaev ◽  
Günter Plunien
Keyword(s):  
Bound State ◽  
Finite Basis ◽  
Basis Set ◽  
Energy Spectra ◽  
Axially Symmetric ◽  
Wide Range ◽  
Monopole Approximation ◽  
Internuclear Distances ◽  
Bound State Qed ◽  
Symmetric Systems

The generalized dual-kinetic-balance approach for axially symmetric systems is employed to solve the two-center Dirac problem. The spectra of one-electron homonuclear quasimolecules are calculated and compared with the previous calculations. The analysis of the monopole approximation with two different choices of the origin is performed. Special attention is paid to the lead and xenon dimers, Pb82+&ndash;Pb82+&ndash;e&minus; and Xe54+&ndash;Xe54+&ndash;e&minus;, where the energies of the ground and several excited &sigma;-states are presented in the wide range of internuclear distances. The developed method provides the quasicomplete finite basis set and allows for construction of the perturbation theory, including within the bound-state QED.

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