Total Energy Spectrum Research Articles

Feasibility verification of deep-learning based collimator-less imaging system using a voxelated GAGG(Ce) single volume detector: A Monte Carlo simulation

A 4π-field of view deep-learning-based collimator-less imaging system was designed with the Monte Carlo method and performance of the system was studied to verify the feasibility of system. A 4 × 4 × 4 voxelated single-volume GAGG(Ce) system and 57Co, 133Ba, 22Na, and 137Cs point sources at 2000 positions were modeled using Monte-Carlo N-particle transport code version 6 (MCNP6). Two types of the localized energy deposition acquired with a voxelated detector system with and without energy bins, were calculated. The F6 tally was used to provide the entire energy deposited in each voxel and the F8 tally to provide energy spectrum data for each voxel. This system utilized these energy deposition patterns depending on the source type and position to reconstruct the source distribution image. A fully convolutional network which is advantageous for the prediction of image outputs was used to estimate source distribution. The models utilizing energy deposition patterns generated on total energy deposition and energy spectrum data were trained with labels from 30° to 10 degree of full-width half-maximum (FWHM). As a result of training with single and multiple source data, types of isotopes and source locations were discriminated up to 5 sources when using energy spectral data, and the average image similarity between ground truth images and predicted ones were 0.9936 for total energy deposition model and 0.9966 for divided energy bin model. These results showed the feasibility of a collimator-less imaging system based on deep learning method that requires no filtration of any type of interaction.

Exploration of crystal structure, supramolecular organization, and computational studies of a novel pyrazole derivative: A structural and theoretical perspectives

An eminent challenge in contemporary medicine and pharmacy is the identification of powerful, biologically active, and benign anti-COVID drugs. The objective of this work is to synthesize 3-chloro-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid to investigate its properties using different spectroscopic methods. The crystal structure of the compound is determined using single-crystal X-ray diffraction methodology. Hirshfeld surface analysis was employed to evaluate the impact of intermolecular interactions on crystal packing. The interactions were visually depicted using 2D fingerprint plots, which highlighted the specific surface area associated with each interactant. Indications suggest that the crystal packing is mostly governed by C-H...O and N-H...O interactions, resulting in the formation of S(7) self-motif and R44(24) synthon, which greatly improve crystal stability. Density functional theory (DFT) was employed to better examine the structural and electrical characteristics. Computations were conducted at the 6–311+G(d,p) level to determine the optimal geometry, total energy, HOMO-LUMO gap, and vibrational spectra. The results showed a HOMO-LUMO gap of 3.092 eV, suggesting a moderate amount of stability. Bader et al. employed reduced density gradient (RDG) techniques and topological analysis, taking into account the quantum theory of atoms in molecules (QTAIM), to examine noncovalent interactions. Additionally, the molecule satisfies Lipinski's rule of five and exhibits encouraging pharmacokinetic activities. Additional in-silico investigations, including molecular docking, were conducted on the SARS-CoV-2 spike protein variation to assist in the advancement of enhanced vaccines and therapeutics.

Evaluation of subgrid-scale models in decaying rotating stratified turbulence

The results of large eddy simulation (LES) using four sub-grid scale (SGS) models, namely: constant coefficient Smagorinsky (CS), dynamic Smagorinsky (DS), a dynamic Clark (DC) model, and dynamic Lund-Novikov II-term model (DLN2M) for rotating stratified turbulence in the absence of forcing using large-scale isotropic initial conditions, are reported here. Three cases with varying ratios of Brunt-Väisälä frequency to the inertial wave frequency, N / f , have been chosen to evaluate the performance of SGS models. The Reynolds number and N / f are chosen as (a) Case 1: Re=3704, N / f = 5 , (b) Case 2: Re=6667, N / f = 40 and (c) Case 3: Re=6667, N / f = 138 . Various quantities including turbulent kinetic energy (tke), turbulent potential energy (tpe), total dissipation, potential and total energy spectra, and their fluxes, are analyzed. It is observed that the increase in the value of N / f leads to increased oscillations in the evolution of kinetic and potential energy. Our results suggest that the inclusion of the rotation rate tensor in SGS modeling leads to overall improvements in energy evolution predictions. The CS model produces the largest errors, while the DS and the DC models are more comparable to each other. Spectral analysis of total energy and their fluxes shows that the CS, DS and DC models can reasonably predict the large-scale motion ( κ < 10 ), while the DLN2M model improves the energy prediction in the wavenumber range ( 10 < κ < 64 ) in comparison to other SGS models.

Ordering self-assembly structures via N[sbnd]H⋯S and Br⋯S interactions in (E)-2-(4-bromobenzylidene)hydrazinecarbothioamide : Insights from crystallographic and computational study

In this research paper, the compound (E)-2-(4-bromobenzylidene)hydrazinecarbothioamide (NC2) was synthesized and characterized by spectroscopic techniques and crystal structure was elucidated using single crystal X-ray diffraction method. The Hirshfeld surface analysis revealed the relative contributions of different intermolecular interactions to crystal packing, while the 2D fingerprint plots provided a visual representation of the intermolecular interactions via the surface area corresponding to each type of interaction. The findings revealed that the crystal packing of the molecule is mostly determined by H…H, C-Br…S and NH…S interactions. We investigated the structural and electronic properties of the compound NC2 using density functional theory (DFT). The optimized geometry, total energy, HOMO-LUMO gap, and vibrational spectra were calculated at the ωB97X/6–311+G(d,p) level of theory. The calculated results showed that the molecule has a stable geometry with a trans-conformation. The HOMO-LUMO gap of 3.813 eV indicates that the molecule has moderate stability. The nature of noncovalent interactions are investigated using the methods reduced density gradient (RDG) and topology analysis like quantum theory of atoms in molecules (QTAIM) proposed by Bader et al. The compound NC2 is found to adhere to the Lipinski's rule of five and exhibit good pharmacokinetic properties.

Angular and energy distributions of positrons created in subcritical and supercritical slow collisions of heavy nuclei

Positron creation probabilities as well as energy and angular distributions of outgoing positrons in slow collisions of two identical heavy nuclei are obtained within the two-center approach beyond the monopole approximation. The time-dependent Dirac equation for positron wave functions is solved with the help of the generalized pseudospectral method in modified prolate spheroidal coordinates adapted for variable internuclear separation. Depending on the nuclear charge, the results are obtained for both subcritical and supercritical regimes of the positron creation. The signatures of transition to the supercritical regime in the total positron creation probabilities and energy spectra are discussed. The angular distributions of emitted positrons demonstrate a high degree of isotropy. Published by the American Physical Society 2024

The all-particle energy spectrum of cosmic rays from 10 TeV to 1 PeV measured with HAWC

The HAWC observatory is an air-shower detector, which is designed to study both astrophysical gamma-rays in the TeV region and galactic cosmic rays in the energy interval from 1 TeV to 1 PeV. This energy regime is interesting for cosmic ray research, since indirect observations overlap with direct measurements, which offers the opportunity for cross calibration and studies of experimental systematic errors in both techniques. One quantity that could help for this purpose is the all-particle energy spectrum of cosmic rays. In this work, we present an update of HAWC measurements on the total cosmic-ray energy spectrum between 10 TeV and 1 PeV. The spectrum was obtained from an unfolding analysis of almost two years of HAWC’s data, which was collected from January, 2018 to December, 2019. For the energy estimation, we employed the high-energy hadronic interaction model QGSJET-II-04. As in a previous work of HAWC, published in 2017, we observed the presence of a knee-like feature in the region of tens of TeV.

Extracting clean low-energy spectra from silicon strip detector telescopes around punch through energies

The response of detector telescopes becomes complex around their relevant punch through energies: For some deposited energies the corresponding particle kinetic energies cannot be uniquely assigned, and these spurious energy regions can span several hundreds of keV if the telescopes are employed in close geometry. We present methods for producing clean low-energy spectra of light ions from detector telescopes consisting of thin double-sided silicon strip detectors (DSSSDs) backed by thick silicon pad detectors. By following these methods, the spectra of several such detector telescopes can be combined to span the entire relevant particle energy spectrum, above as well as below the punch through thresholds of the individual telescopes. The total energy spectrum resulting from the combination of all telescope spectra thus encompass the entire particle energy distribution in conjunction with the energy-dependent, setup-specific solid angle coverage. Energy spectra of beta-delayed proton emission from 21Mg are used to illustrate the methods.

A Self-Consistent Exact Diagonalization Approach to the Ground State Magnetic Properties of the Meridional [V(ddpd)2]3+ Complex

The present paper presents a thorough study of the ground state magnetic properties of the spin-one mononuclear nanomagnet mer-[V(ddpd)2][PF6]3, with the V3+ center exhibiting a distorted octahedral coordination. The theoretical analysis is based on a multiconfigurational, self-consistent approach that effectively parametrizes the total energy spectrum of the considered coordination complex via exact diagonalization. We provide a comprehensive discussion for the obtained zero-field and field-dependent fine structure of the ground state along with the ensuing crystal field splitting of the 3d orbitals. Furthermore, we report the results for the low-field susceptibility, magnetization and the corresponding reversal dynamics, finding good agreement with the experimental data reported in the literature. The calculations show considerable zero-field splitting and strong field-dependent orbital unquenching underlying the occurrence of a field-induced full profile magnetization reversal barrier.

Sedimentary features of the gravity flow influenced shale deposit: A case study of Chang 7 member in the Ordos Basin, China

Black shale deposits are usually regarded to be deposited in a relatively slack and deep water environment. The gravity flows that can greatly affect the shale depositional process are well documented in many marine basins, with much less attention paid to the counterpart in lacustrine settings. The Upper Triassic Chang 7 Member in the Ordos Basin, which contains thick black shale and well developed gravity flow deposits provides a good opportunity to investigate the influence of gravity flows on shale development in lacustrine settings. We integrate X-ray diffraction, thin section petrography analysis, major and trace element analysis, total organic carbon testing, electron microscopy, and energy spectrum analysis on shale to reveal such complicated process. Based on the development of silty laminas and thickness of the laminaset/bedding, we classified the Chang 7 shale into five lithofacies. Each lithofacies was unique in terms of laminar morphology, texture, and composition, indicating different depositional processes. Proxies of paleo-water depth, paleo-settling rate, paleo-productivity, paleo-redox, and clastic influx also revealed that these five lithofacies deposited in different depositional settings. We propose new depositional models to explain such heterogenous shale deposits and suggest the paleo-productivity has the strongest influence on the accumulation of organic matter.

Ocean Model Response to Stochastically Perturbed Momentum Fluxes

Abstract Recent studies of various stochastic forcing and subgrid-scale parameterization schemes applied to climate and atmospheric models have revealed a diversity of model responses. These responses include degeneracy in the response to different forcings and compensating model errors. While stochastic parameterization of the ocean eddies is an active area, this has mainly involved idealized models with fewer studies employing ocean general circulation models. Here we examine the sensitivity of a low-resolution climate model to stochastic forcing of the momentum fluxes restricted to regions of the three-dimensional ocean where an eddy-resolving ocean model configuration has high variability. We consider the changes in the modeled energetics of low-resolution simulations in response to increased stochastic forcing. We find that as forcing amplitudes are increased there is enhanced conversion of transient to seasonal potential energy. Additionally, there is a systematic redistribution from seasonal to small-scale transient kinetic energy. Our approach has zero mean noise such that the total kinetic energy spectra remain largely unchanged even as small-scale eddy kinetic energy is increased in the targeted regions. However, we also show that strong stochastic forcing, particularly when applied in the tropics, can induce substantial changes to the ocean steady state that are undesirable. These changes include overly strong vertical mixing leading to unrealistic increases in ocean heat content and latitudinally dependent changes to sea level. We show that judicious selection of the magnitude and spatial extent of the stochastic forcing is required for desirable results. Our results point to the importance of a comprehensive evaluation of ocean model responses to stochastic parameterizations.

Generalized Kohn-Sham equations with accurate total energy and single-particle eigenvalue spectrum.

We propose a new generalized Kohn-Sham or constrained hybrid method, where the exchange potential is the (equally weighted) average of the nonlocal Fock-exchange term and the self-interaction-corrected exchange potential, as obtained from our constrained minimization method of semi-local approximations. The new method gives an accurate single-particle eigenvalue spectrum with an average deviation between (the negative of) the valence orbital eigenvalues and the experimental ionization potentials of about 0.5eV, while the deviation of core orbitals is within 2eV. The improvement in the eigenvalue spectrum is achieved with a minimal increase in the total energy.

Primordial black holes and stochastic gravitational wave background from inflation with a noncanonical spectator field

We investigate the enhancement of the curvature perturbations in a single-field slow-roll inflation with a spectator scalar field kinetically coupled to the inflaton. The coupling term with a periodic function of inflaton triggers the exponential growth of the spectator field perturbations, which indirectly amplifies the curvature perturbations to produce a sizable abundance of primordial black holes (PBHs). This scenario is found to be insensitive to the inflationary background. We study two distinct populations of the stochastic gravitational wave background (SGWB) produced in this scenario, i.e., induced by the scalar perturbations during the inflationary era and the radiation-dominated era, respectively. With the appropriate choices of parameter space, we consider two PBH mass windows of great interest. One is PBHs of masses $\mathcal{O}(10^{-12})M_\odot$ that can be a vital component of dark matter, and the predicted total energy spectrum of SGWB shows a unique profile and is detectable by LISA and Taiji. The other is PBHs of masses $\mathcal{O}(10)M_\odot$ which can provide consistent explanation for the LIGO-Virgo events. More interestingly, the predicted gravitational wave signal from the radiation-dominated era may account for the NANOGrav results.

Effects of the secondary baroclinic vorticity on the energy cascade in the Richtmyer–Meshkov instability

We investigate the effect of the secondary baroclinic vorticity (SBV) on the energy cascade in the mixing induced by the multi-mode Richtmyer–Meshkov instability (RMI). With the aid of vorticity-based simplified models and the vortex-surface field, we find that the effect of the SBV peaks at a critical time when the vortex reconnection widely occurs in the mixing zone. Before the critical time, spikes and bubbles evolve almost independently, and we demonstrate that the variation of the kinetic energy spectrum induced by the SBV has the $-1$ scaling law at intermediate wavenumbers using the model of vortex rings. This SBV effect causes the slope of the total energy spectrum at intermediate wavenumbers to evolve towards $-3/2$ at the critical time. Subsequently, the SBV effect diminishes and the energy spectrum decays to the $-5/3$ law. Inspired by the vortex dynamics, we develop a model for estimating the mixing width and validate the model using numerical simulations of the multi-mode RMI with various modes of initial perturbations. This model captures the nonlinear growth of the mixing width before the self-similar growth stage.

Structural and physical properties of trichloroethylene under an external electric field

AbstractStudy on a series of physical and chemical changes of molecules under an external electric field (EEF) can deeply understand the properties of molecules. Trichloroethylene is widely used in industrial solvents, extractants, fungicides, refrigerants, dry cleaning, and other fields. In this work, the structural and physical characteristics of trichloroethylene under EEF were investigated on the basis of density functional theory within the B3LYP/def2‐TZVP level. Calculated results show that the bond lengths, bond angles, total energy, dipole moment, charge, and Raman spectra change under EEF. Under the effect of EEF, the Raman spectra show vibrational stark effect, which causes a redshift or blueshift of the wavenumbers. These results help to understand the effect of EEF on structures and physical properties and provide effective guidance for various applications.

Barotropic and baroclinic tides in Panay Strait, Philippines

The Panay Strait constitutes a bathymetrically complex system with intense tidal currents. The four major tidal constituents in the total energy spectra inferred from sea level and current profiles are K1, O1, M2, and S2. Spatially, O1 and M2 dominate over K1 and S2, respectively. The diurnal tide accounts for highest amplitude variability over the shallow shelf while semi-diurnal tides over the deeper channel of the strait. Rotary spectra of surface currents shows inertial frequency peaks and exhibit an unusually broad peak in both the clockwise (CW) and counterclockwise (CCW) rotating components, indicating frequency shift by the vorticity of sub-inertial currents prevalent in the region. Vertically, variance of the horizontal velocity explained by the major tidal constituents peaks in two distinct depth bands; the upper layer centered at 110 m (11% variance) dominated by semi-diurnal tide (M2) and the lower layer at 470 m (26% variance) dominated by diurnal tides (O1). Semi-diurnal tidal current ellipses (M2 and S2) exhibit a dominance of CW motions at near-surface depth (110 m), indicative of downward energy propagation and implying a surface energy source. These features from Acoustic Doppler Current Profiler (ADCP) deployed close to the sill is consistent with the dominant semi-diurnal tide (M2) over the channel of the strait from the High Frequency Doppler Radar (HFDR). Comparison of incoherent to coherent tidal energy shows K1 dominated the incoherent tidal band. Spatially, incoherent energy is dominant over the channel particularly near the sill and the constricted part of the strait. The incoherent portion of the tide is presumably attributable to the surface expression of the internal tide which seems to be generated near the sill and then topographically steered west over the edge of the shallow shelf where incoherent energy is dominant.

Addendum to: Updated constraints on non-standard interactions from global analysis of oscillation data

In this addendum we re-assess the constraints on Non-Standard Interactions (NSI) from the global analysis of neutrino oscillation data after including the new results released since the publication of ref. [1], in particular those presented at the Neutrino2020 conference. The new data considered here includes the total energy spectrum and the day-night asymmetry of the 2970-day SK4 solar neutrino sample [2], as well as the latest results from long-baseline (LBL) experiments T2K [3, 4] and NOvA [5, 6]. In addition, we have updated the reactor experiments Double-Chooz [7, 8] to 1276/587 days of far/near detector data and RENO [9, 10] to 2908 days of exposure.

Multi-neutron transfer in He8 -induced reactions near the Coulomb barrier

The measured inclusive $^6$He and $^4$He production cross sections of G. Marqu{\'i}nez-Dur{\'a}n {\em et al.}, Phys.\ Rev.\ C {\bf 98}, 034615 (2018) are reexamined and the conclusions concerning the relative importance of 1n and 2n transfer to the production of $^6$He arising from the interaction of a 22 MeV $^8$He beam with a $^{208}$Pb target revised. A consideration of the kinematics of the 2n-stripping reaction when compared with the measured $^6$He total energy versus angle spectrum places strict limits on the allowed excitation energy of the $^{210}$Pb residual, so constraining distorted wave Born approximation calculations that the contribution of the 2n stripping process to the inclusive $^6$He production can only be relatively small. It is therefore concluded that the dominant $^6$He production mechanism must be 1n stripping followed by decay of the $^7$He ejectile. Based on this result we present strong arguments in favor of direct, one step four-neutron (4n) stripping as the main mechanism for $^4$He production.

Assessment of SGS Models for Large Eddy Simulation (LES) of a Stratified Taylor–Green Vortex

Eddy viscosity-based and regularization-based subgrid-scale (SGS) models are quantitatively assessed for large eddy simulations (LES) of stratified Taylor–Green vortex (TGV). LES calculations using the dynamic Smagorinsky, Leray- $$\alpha$$ , LANS- $$\alpha$$ and Clark- $$\alpha$$ models are conducted using a pseudo-spectral formulation on a $$128^{3}$$ grid and using $$\alpha =\frac{1}{160}$$ (for all the regularization models) for Froude number, $$Fr_0=\frac{{\mathcal {U}}}{{{\mathcal {N}}}{{\mathcal {L}}}}=1$$ , and Reynolds number, $$Re_{0}= \frac{\mathcal {U L} }{\nu }=1600$$ . Results are compared in detail with in-house direct numerical simulation (DNS) calculations. Validation of the formulation is carried out through grid-dependent studies using grids of $$64^3$$ , $$128^3$$ and $$256^3$$ , $$\alpha$$ (regularization parameter)-dependent studies using $$\alpha$$ values of $$\frac{1}{40}, \frac{1}{80}, \frac{1}{160}$$ and $$\frac{1}{320}$$ , and comparisons with previously published results Remmler and Hickel, 2012, of the same problem. Various quantities including turbulent kinetic energy (tke), turbulent potential energy (tpe), Q-criteria based vortical structures, potential & total energy spectra, and horizontal & vertical energy fluxes in the respective directions, are analyzed to understand the capability of the various LES models in predicting the development of stratified turbulence. Results showed that all the SGS model predictions were very similar to each other with Smagorinsky and Leray displaying the lowest and highest errors, respectively, in comparison to DNS. The effect of $$Fr_0$$ was also studied through additional LES calculations at $$Fr_0=0.5$$ and 0.16, again using the dynamic Smagorinsky and regularization models and comparing various parameters including tke, tpe and energy spectra to DNS. Decay rates of tke and tpe decreased and turbulence was significantly suppressed with decrease in $$Fr_0$$ . At these lower $$Fr_0$$ , all the SGS model predictions were almost identical to each other and compared extremely well with the DNS results.

Approaching the neutron-rich heavy and superheavy nuclei by multinucleon transfer reactions with radioactive isotopes

The dynamical mechanism of multinucleon transfer (MNT) reactions has been investigated within the dinuclear system (DNS) model, in which the sequential nucleon transfer is described by solving a set of microscopically derived master equations. Production cross sections, total kinetic energy spectra, angular distribution of formed fragments in the reactions of $^{124,132}$Sn+ $^{238}$U/$^{248}$Cm near Coulomb barrier energies are thoroughly analyzed. It is found that the total kinetic energies of primary fragments are dissipated from the relative motion energy and rotational energy of the two colliding nuclei. The fragments are formed in the forward angle domain. The energy dependence of the angular spectra is different between projectile-like and target-like fragments. Isospin equilibrium is governed under the potential energy surface. The production cross sections of neutron-rich isotopes are enhanced around the shell closure.

Theory of elastic neutrino-electron scattering

Theoretical predictions for elastic neutrino-electron scattering have no hadronic or nuclear uncertainties at leading order making this process an important tool for normalizing neutrino flux. However, the process is subject to large radiative corrections that differ according to experimental conditions. In this paper, we collect new and existing results for total and differential cross sections accompanied by radiation of one photon, $\nu e \to \nu e (\gamma)$. We perform calculations within the Fermi effective theory and provide analytic expressions for the electron energy spectrum and for the total electromagnetic energy spectrum as well as for double- and triple-differential cross sections with respect to electron energy, electron angle, photon energy, and photon angle. We discuss illustrative applications to accelerator-based neutrino experiments and provide the most precise up-to-date values of neutrino-electron scattering cross sections. We present an analysis of theoretical error, which is dominated by the $\sim 0.2 - 0.4\%$ uncertainty of the hadronic correction. We also discuss how searches for new physics can be affected by radiative corrections.