Energy Correction Method Research Articles

Unraveling the charge transfer variation of tetrathiafulvalene-based organic crystals through fragment charge difference calculation

Organic crystals assembled by a well-established family of electron donors, tetrathiafulvalene (TTF)-based molecules, hold great potential for electronics, smart materials, and superconductors. Combining with Marcus' theory and first-principles calculations, we have adopted a fragment charge difference (FCD) method to investigate the charge transfer properties of the TTF-based crystals. Our FCD predictions are highly consistent with those obtained from a well-accepted site energy correction method. We have demonstrated the significant influence of both structure and chemistry on the charge transfer properties using polymorphs, i.e., α-phase tetrathiafulvalene (1) versus β-phase tetrathiafulvalene (2), and crystals with homologous molecular packings, i.e., 1 versus dithiophene-TTF (3). We have also introduced multiple factors to provide further insights into the variation in charge transfer properties of the TTF-based crystals, including energy gap (∆E), centroid distance (ri), orbital distribution correction factor (Hs), and reorganization energy (λ). By taking advantage of our analysis, we have rationalized high mobility in hexamethylene-TTF (4) and low mobility in bis(ethylenedithio)-TTF (5). Our multiple-factor evaluation could support an approach to designing electrically conducting TTF-based materials and provide a method to estimate charge transfer properties effectively.

DOI correction for gamma ray energy reconstruction based on energy segment in 3D position-sensitive CdZnTe detectors

The amplitude of the induced signal in 3D CdZnTe detector depends on the depth of interaction (DOI). Therefore, calibrating the detector by using DOI correction technology plays a crucial role in improving the energy resolution of the detectors to gamma rays. The current DOI correction method focuses on the single energy gamma rays, and its application to multiple energy gamma-rays are not found. In this study, we propose an improved energy correction algorithm with excellent correction results in the multiple energy gamma-ray detection. In the experiment, the DOI correction factors of a CdZnTe detector under different energies are discussed. The energy resolution and peak height of multiple energy peaks in the energy spectrum are significantly improved by using the segment energy correction method. We also extend the DOI correction method to the gamma detectors used in the Compton imaging, and the influence of this method on the Compton imaging quality is also discussed. For a single 60Co point source, the intrinsic efficiency increases from 6.5‰ to 8.3‰.

A SOE estimation method for lithium batteries considering available energy and recovered energy

State of energy (SOE) is a critical index of lithium battery. The problem of the inaccurate available energy and recovered energy of lithium battery affects the accuracy of SOE estimation. In order to solve the problem, this paper proposes a method to estimate the available discharge energy of lithium batteries based on response surface model. In this method, the energy efficiency of lithium batteries in different states is obtained by establishing the relationship model of external charge voltage and external discharge voltage, so as to estimate the actual available energy of lithium batteries in different charge states. On this basis, a correction method based on radial basis function (RBF) neural network is proposed to estimate the actual energy released by the recovered energy when the current direction of the battery is changed. The proposed energy correction method is combined with the adaptive particle filter algorithm to estimate SOE. This method is not limited to the assumption of Gaussian function and can accurately predict the noise variance, so as to improve the estimation accuracy of SOE. Simulations under urban dynamometer driving schedule (UDDS) are conducted, and the result shows that the proposed method can effectively estimate the battery energy and improve the accuracy of SOE estimation.

An FPGA Based energy correction method for one-to-one coupled PET detector: model and evaluation

A PET scanner based on silicon photomultipliers (SiPMs) has been widely used as an advanced nuclear medicine imaging technique that yields quantitative images of regional in vivo biology and biochemistry. The compact size of the SiPM allows direct one-to-one coupling between the scintillation crystal and the photosensor, yielding better timing and energy resolutions than the light sharing methods that have to be used in photomultiplier tube (PMT) PET systems. To decrease the volume of readout electronics, a front-end multiplexer with position decoder is a common choice for the one-to-one system without a highly integrated application specific integrated circuit (ASIC). However, in this case we cannot measure each crystal's deposited energy inspired by an annihilation photon, so the inter-crystal scatter (ICS) events will lead to the crystal mispositioning and then deteriorate the detector intrinsic resolution. Besides, considering the events rejection within the energy window resulting from the gain dispersion and non-linear outputs of the SiPMs, an energy correction mechanism is needed. Yet, lack of the information of each crystal's energy will introduce large energy correction error for the ICS events. For this issue, an online energy correction mechanism implemented on a Kintext-7 Field Programmable Gate Array (FPGA) device is presented in this paper. Experiments in the laboratory were performed using an 8 × 8 segmented LYSO crystals coupled with an 8 × 8 SiPM (J-series, from ON Semiconductor) array which is under 22Na point source excitation. Test results indicate that both the energy of the non-ICS and ICS events can be precisely corrected and the energy resolution is better than 12 %. We also applied this method to an actual clinical PET scanner under a 68Ge line source to verify its multi-channel reliability.

Energy balance and energy correction in dynamics of classical spin systems.

An energy-correction method is proposed as an addition to mainstream integrators for equations of motion of systems of classical spins. This solves the problem of nonconservation of energy in long computations and makes mainstream integrators competitive with symplectic integrators for spin systems that for different-site interactions conserve the energy explicitly. The proposed method is promising for spin systems with single-site interactions for which symplectic integrators do not conserve energy and thus have no edge against mainstream integrators. From the energy balance in the spin system with a phenomenological damping and Langevin fields, a formula for the dynamical spin temperature in the presence of single-site anisotropy is obtained.

Wave dispersion and quantitative accuracy analysis of bond-based peridynamic models with different attenuation functions

Peridynamics (PD) reformulates classical continuum mechanics in terms of spatial integral equations rather than partial differential equations. PD has successfully matched fracture patterns observed in experiments. However, issues remain, such as its dispersion characteristics, constant micromodules, and behavior at material boundaries. The introduction of attenuation functions can effectively address these three problems. In this study, we attempted to conduct a systematic investigation of bond-based peridynamics (BPD) with different attenuation functions. This mainly involved an analysis of the wave dispersion, surface effect, and quantitative accuracy of BPD models with different attenuation functions. Initially, a novel quartic polynomial attenuation function was proposed, and various types of functions were investigated. The corresponding expressions for non-constant micromodulus functions were determined, and attenuation bond-based peridynamic (ABPD) models that considered the effect of attenuation were established. Furthermore, the dispersion relationship of ABPD for the one-dimensional case was derived, and the effects of the horizon size, material point size, and attenuation functions on the dispersion properties were investigated. Finally, the surface effect and the effectiveness of different attenuation functions were examined by considering the attenuation functions and energy correction method in ABPD models under plane stress and plane strain conditions. Thus, the accuracy of ABPD was evaluated. The influence function proposed in this work and other several attenuation functions can be used to minimize wave dispersion for a fixed material point size or horizon size and to reduce the surface effect. The energy correction method had a remarkable influence on the computational accuracies of the classical BPD model and ABPD models. Practical recommendations for selecting the attenuation functions for coupling PD with other methods and for enhancing the accuracy of the BPD model were provided.

Development of a new database for Auger electron and X-ray spectra

An energy correction method is described to account for the Breit and QED effects on Auger electrons and X-ray energies in the recently developed atomic relaxation model BrIccEmis. The results are compared with literature and new experimental data for Z = 52. Overall this improves the agreement of the calculated energies with the literature values. A new atomic radiation database NS_Radlist, will contain atomic transition energies from the BrIccEmis program with these energy corrections.

Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter

For personal radiation dose monitoring, electronic personal dosimeters (EPD), also known as active personal dosimeter (APD), using silicon diode detector have the advantage capability of measuring and displaying directly the exposure results of gamma, beta and neutron radiations in real time. They are mainly considered as good complement to passive dosimeters to satisfy ALARA principle in the radiation protection. In this paper, the meansurement methods and algorithms for evaluating personal dose equivalents such as Hp(10) and Hp(0.07) from air-kerma are studied and developed in two directions: the first, named energy correction method based on incident energy determined by the ratio of two detector responses with the different filter configurations; the second new method is carried out in the way that matching the shape of a detector’s energy response curve to the kerma-to-personal dose equivalent conversion function provides an approximate means of determining the dose equivalent without the need to resolve the actual incident energies. The algorithm has also been experimentally verified at Secondary Standards Dosimetry Laboratory (SSDL) of INST by the beam of radiation defined in ISO 4037-1. The obtained results of personal dose equivalents with errors almost less than 30% in energy range from 20 keV to 1.5 MeV are partially met the EPD design requirements according to the IEC 61526 Standard. The work and results of described in this paper are important basics for design and construction of completed electronic personal dosimeter.

Solution of the Skyrme-Hartree–Fock–Bogolyubovequations in the Cartesian deformed harmonic-oscillator basis. (VIII) hfodd (v2.73y): A new version of the program

We describe the new version (v2.73y) of the code hfodd which solves the nuclear Skyrme Hartree–Fock or Skyrme Hartree–Fock–Bogolyubov problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we have implemented the following new features: (i) full proton–neutron mixing in the particle–hole channel for Skyrme functionals, (ii) the Gogny force in both particle–hole and particle–particle channels, (iii) linear multi-constraint method at finite temperature, (iv) fission toolkit including the constraint on the number of particles in the neck between two fragments, calculation of the interaction energy between fragments, and calculation of the nuclear and Coulomb energy of each fragment, (v) the new version 200d of the code hfbtho, together with an enhanced interface between hfbtho and hfodd, (vi) parallel capabilities, significantly extended by adding several restart options for large-scale jobs, (vii) the Lipkin translational energy correction method with pairing, (viii) higher-order Lipkin particle-number corrections, (ix) interface to a program plotting single-particle energies or Routhians, (x) strong-force isospin-symmetry-breaking terms, and (xi) the Augmented Lagrangian Method for calculations with 3D constraints on angular momentum and isospin. Finally, an important bug related to the calculation of the entropy at finite temperature and several other little significant errors of the previous published version were corrected. Program summaryTitle of the program:hfodd (v2.73y)Program Files doi:http://dx.doi.org/10.17632/3b28fs62wc.1Licensing provisions: GPL v3Programming language: FORTRAN-90Journal reference of previous version: N. Schunck, J. Dobaczewski, J. McDonnell, W. Satuła, J. Sheikh, A. Staszczak, M. Stoitsov, and P. Toivanen, Comput. Phys. Comm. 183 (2012) 166-192.Does the new version supersede the previous one: YesNature of problem: The nuclear mean field and an analysis of its symmetries in realistic cases are the main ingredients of a description of nuclear states. For the density functional generated by a zero-range velocity-dependent Skyrme interaction, the nuclear mean field is quasilocal. This allows for an effective and fast solution of the self-consistent Hartree–Fock equations, even for heavy nuclei, and for various nucleonic (n-particle n-hole) configurations, deformations, excitation energies, or angular momenta. Similarly, the local particle–particle density functional, generated by a zero-range interaction, allows for a simple implementation of pairing effects within the Hartree–Fock–Bogolyubov method. For finite-range interactions, like Coulomb, Yukawa, or Gogny interaction, the nuclear mean field becomes nonlocal, but using the spatial separability of the deformed harmonic-oscillator basis in three Cartesian directions, the self-consistent calculations can be efficiently performed.Solution method: The program uses the Cartesian harmonic oscillator basis to expand single-particle or single-quasiparticle wave functions of neutrons and protons interacting by means of the Skyrme or Gogny effective interactions and zero-range or finite-range pairing interactions. The expansion coefficients are determined by the iterative diagonalization of the mean-field Hamiltonians or Routhians which depend non-linearly on the local or nonlocal neutron, proton, or mixed proton–neutron densities. Suitable constraints are used to obtain states corresponding to a given configuration, deformation or angular momentum. The method of solution has been presented in: J. Dobaczewski and J. Dudek, Comput. Phys. Comm. 102 (1997) 166.Summary of revisions:1.Full proton–neutron mixing in the particle–hole channel for Skyrme functionals was implemented.2.The Gogny force was implemented in both particle–hole and particle–particle channels.3.Linear multi-constraint method based on the cranking approximation of the QRPA matrix was extended at finite temperature.4.Fission toolkit includes the constraint on the number of particles in the neck between two fragments, calculation of the interaction energy between fragments, and calculation of the nuclear and Coulomb energy of each fragment.5.The HFBTHO module was updated to version 200d, and an enhanced interface between HFBTHO and HFODD was implemented.6.Parallel capabilities were significantly extended by adding several restart options for large-scale jobs.7.The Lipkin translational energy correction method with pairing was implemented.8.Higher-order Lipkin particle-number corrections were implemented.9.Interface to a program plotting single-particle energies or Routhians was added.10.Strong-force isospin-symmetry-breaking terms were implemented.11.The Augmented Lagrangian Method for calculations with 3D constraints on angular momentum and isospin was implemented.12.An important bug related to the calculation of the entropy at finite temperature and several other little significant errors of the previous published version were corrected.Unusual features of the program: The user must have access to (i) the LAPACK subroutines zhpev, zhpevx, zheevr, or zheevd, which diagonalize complex hermitian matrices, (ii) the LAPACK subroutines dgetri and dgetrf which invert arbitrary real matrices, (iii) the LAPACK subroutines dsyevd, dsytrf and dsytri which compute eigenvalues and eigenfunctions of real symmetric matrices and (iv) the LINPACK subroutines zgedi and zgeco, which invert arbitrary complex matrices and calculate determinants, (v) the BLAS routines dcopy, dscal, dgeem and dgemv for double-precision linear algebra and zcopy, zdscal, zgeem and zgemv for complex linear algebra, or provide another set of subroutines that can perform such tasks. The BLAS and LAPACK subroutines can be obtained from the Netlib Repository at the University of Tennessee, Knoxville: http://netlib2.cs.utk.edu/.

A parameterized energy correction method for electromagnetic showers in BGO-ECAL of DAMPE

DAMPE is a space-based mission designed as a high energy particle detector measuring cosmic-rays and γ-rays which was successfully launched on Dec.17, 2015. The BGO electromagnetic calorimeter is one of the key sub-detectors of DAMPE for energy measurement of electromagnetic showers produced by e±/γ. Due to energy loss in dead material and energy leakage outside the calorimeter, the deposited energy in BGO underestimates the primary energy of incident e±/γ. In this paper, based on detailed MC simulations, a parameterized energy correction method using the lateral and longitudinal information of electromagnetic showers has been studied and verified with data of electron beam test at CERN. The measurements of energy linearity and resolution are significant improved by applying this correction method for electromagnetic showers.

Evaluating one- and two-source energy balance models in estimating surface evapotranspiration from Landsat-derived surface temperature and field measurements

This article compares one- and two-source energy balance (OSEB and TSEB) models in the estimates of surface energy components using Landsat imagery and surface measurements acquired from an experimental field at Yucheng Station in Northern China. Compared to surface measurements, similar performance between the TSEB and OSEB models has been observed for estimated surface net radiation and soil heat flux. The root mean square difference (RMSD) is within 14–39 W m−2 in both the TSEB and OSEB models. The residual energy (E R) correction method yields the best agreement in comparisons of the sensible (H) and latent (LE) heat fluxes estimated using both the TSEB and OSEB models to the eddy covariance (EC) system measurements. The TSEB model is shown to greatly outperform the OSEB model in reproducing surface H and LE measurements. Cirrus clouds are likely responsible for the surface temperature retrieved from the enhanced thematic mapper plus (ETM+) sensor being lower than air temperature on days of the year (DOYs) 178 and 218 of 2009. This atmospheric stability is contrary to the unstable atmosphere that the EC measurements observe. If data on these two days are excluded and the E R correction method is applied, when comparing the estimated H and LE to the EC measurements, RMSD is within 55 W m−2 in the TSEB model and is larger than 97 W m−2 in the OSEB model.

Evaluating the SEBS‐estimated evaporative fraction from MODIS data for a complex underlying surface

AbstractWith the complex nature of land surfaces, more attention should be paid to the performance of remotely sensed models to estimate evapotranspiration from moderate and low spatial resolution data. Taking into account the characteristic of a stable evaporative fraction (EF) in the daytime, this paper uses the surface energy balance system (SEBS) to estimate the EF from MODIS data for a subtropical evergreen coniferous plantation in southern China and evaluates the stability of the SEBS model in estimating the EF under complex surface conditions. The results show that the SEBS‐estimated EF is larger than the measured EF partly because of the serious lack of energy‐balance closure. This difference can be largely reduced by the residual energy correction method. More evaporative land cover within the MODIS pixel is a main reason for the overestimated EF. SEBS underestimates sensible heat flux, and the underestimation of surface available energy also contributes to the overestimation of the EF. The EF estimated from MODIS/Terra data is in agreement with that from MODIS/Aqua data with a coefficient of determination (R2) of 0.552, a mean bias error (BIAS) of 0.028, and a root mean square error (RMSE) of 0.079, which is consistent with the result from in situ measurements. In addition, the estimation of surface available energy from remotely sensed data is evaluated on this complex underlying surface. Compared with in situ measurements, the available energy is underestimated by 28 W m−2 with an RMSE = 50 W m−2 and an R2 = 0.87. Copyright © 2012 John Wiley & Sons, Ltd.

Solution of the Skyrme–Hartree–Fock–Bogolyubov equations in the Cartesian deformed harmonic-oscillator basis.: (VII) hfodd (v2.49t): A new version of the program

We describe the new version (v2.49t) of the code HFODD which solves the nuclear Skyrme Hartree-Fock (HF) or Skyrme Hartree-Fock-Bogolyubov (HFB) problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we have implemented the following physics features: (i) the isospin mixing and projection, (ii) the finite temperature formalism for the HFB and HF+BCS methods, (iii) the Lipkin translational energy correction method, (iv) the calculation of the shell correction. A number of specific numerical methods have also been implemented in order to deal with large-scale multi-constraint calculations and hardware limitations: (i) the two-basis method for the HFB method, (ii) the Augmented Lagrangian Method (ALM) for multi-constraint calculations, (iii) the linear constraint method based on the approximation of the RPA matrix for multi-constraint calculations, (iv) an interface with the axial and parity-conserving Skyrme-HFB code HFBTHO, (v) the mixing of the HF or HFB matrix elements instead of the HF fields. Special care has been paid to using the code on massively parallel leadership class computers. For this purpose, the following features are now available with this version: (i) the Message Passing Interface (MPI) framework, (ii) scalable input data routines, (iii) multi-threading via OpenMP pragmas, (iv) parallel diagonalization of the HFB matrix in the simplex breaking case using the ScaLAPACK library. Finally, several little significant errors of the previous published version were corrected.

Predictability of the polymorphs of small organic compounds: Crystal structure predictions of four benchmark blind test molecules

Predicting the crystal structure of an organic molecule from first principles has been a major challenge in physical chemistry. Recently, the application of Density Functional Theory including a dispersive energy correction (the DFT(d) method) has been shown to be a reliable method for predicting experimental structures based purely on their ranking according to lattice energy. Further validation results of the application of the DFT(d) method to four organic molecules are presented here. The compounds were targets (labelled molecule II, VI, VII and XI) in previous blind tests of crystal structure prediction, and their structures proved difficult to predict. However, this study shows that the DFT(d) approach is capable of predicting the solid state structures of these small molecules. For molecule VII, the most stable (rank 1) predicted crystal structure corresponds to the experimentally observed structure. For molecule VI, the rank 1, 2 and 3 predicted structures correspond to the three experimental polymorphs, forms I, III and II, respectively. For molecules II and XI, their rank 1 predicted structures are energetically more stable than those corresponding to the experimental crystal structures, and were not found amongst the structures submitted by the participants in the blind tests. The rank 1 structure of molecule II is predicted to exist under high pressure, whilst the rank 1 structure predicted for molecule XI has the same space group and hydrogen bonding pattern as observed in the crystal of 1-amino-1-methyl-cyclopropane, which is structurally related to molecule XI. The experimental crystal structure of molecule II corresponds to the rank 4 prediction, 0.8 kJ mol(-1) above the global minimum structure, and the experimental structure of molecule XI corresponds to the rank 2 prediction, 0.4 kJ mol(-1) above the global minimum.

Real-time gain shift correction for on-line alpha-liquid scintillation spectroscopy

A method for real-time correction of α -particle energy calibration in the SISAK detection system has been developed. The scintillation light yield is continuously monitored by measuring the inflection point of the Compton electron spectrum from a 137Cs source. The energy of any registered α -particle in the SISAK liquid scintillation detection cells is corrected using the scintillation light yield, resulting in an energy resolution of ∼ 300 keV . An experiment with the transactinide 257Rf is described which demonstrates that this energy correction method works well under actual experimental conditions.

Quantum chemical study on reaction of O( 3P) with ClONO 2

The reaction of O( 3P) with ClONO 2 was studied by means of the density functional method at the B3PW91/6-31G(d) level and the correlation energy correction method at the MP2/6-311G(2df) level. Geometries, energies, and vibrational frequencies of reactants, transition states, intermediates and products for the investigated reaction were examined. The energies were also computed by employing the quadratic CI calculation at the QCISD/6-311G(2df) level. The reaction mechanism was investigated.

Reaction of O( 3P) with ClONO 2: a MP2 computation

The reaction of O( 3P) with ClONO 2 were studied by means of the density functional method at the B3PW91/6-31G(d) level and the correlation energy correction method at the MP2/6-311G(2df) level. Geometries, energies, and vibrational frequencies of reactants, transition states, intermediates and products for the examined reaction were examined. The reliable energies were also computed by employing the quadratic CI calculation at the QCISD/6-311G(2df) level. The reaction mechanism was investigated.

Thermodynamic analysis of compact formation; compaction, unloading, and ejection: I. Design and development of a compaction calorimeter and mechanical and thermal energy determinations of powder compaction

The aim of this investigation was to determine and evaluate the thermodynamic properties, i.e. heat, work, and internal energy change, of the compaction process by developing a ‘Compaction Calorimeter’. Compaction of common excipients and acetaminophen was performed by a double-ended, constant-strain tableting waveform utilizing an instrumented ‘Compaction Simulator.’ A constant-strain waveform provides a specific quantity of applied compaction work. A calorimeter, built around the dies, used a metal oxide thermistor to measure the temperature of the system. A resolution of 0.0001°C with a sampling time of 5 s was used to monitor the temperature. An aluminum die within a plastic insulating die, in conjunction with fiberglass punches, comprised the calorimeter. Mechanical (work) and thermal (heat) calibrations of the elastic punch deformation were performed. An energy correction method was outlined to account for system heat effects and mechanical work of the punches. Compaction simulator transducers measured upper and lower punch forces and displacements. Measurements of the effective heat capacity of the samples were performed utilizing an electrical resistance heater. Specific heat capacities of the samples were determined by differential scanning calorimetry. The calibration techniques were utilized to determine heat, work, and the change in internal energies of powder compaction. Future publications will address the thermodynamic evaluation of the tablet sub-processes of unloading and ejection.

Calorimetric analysis of powder compression: I. Design and development of a compression calorimeter

The heat of compression and work of compression of three common pharmaceutical excipients (Avicel PH-101, anhydrous lactose, and Starch 1500) were determined using experimental instrumentation of original design. The heat of compression was independently determined using two different temperature sensors: a tungsten wire temperature sensor positioned within the powder sample and a two-thermistor system positioned behind thin metal plates in the lower surface of the upper punch. The effective heat capacity of the sample when contained within the punch and die apparatus was determined by a simultaneous heating and compression method. An energy correction method was used to account for system heat effects. Upper and lower punch force transducers and a displacement transducer were used to determine the work of compression. In the materials studied, exothermic powder compression subprocesses outweighed the endothermic subprocesses and an overall net exotherm was observed. The rank orders of the heats of compression determined from the in-sample and in-punch temperature sensors were in agreement. This instrumentation and approach, while still being developed, is proposed as a discriminating method to characterize and quantitate fundamental powder compression behavior.

Encircled energy correction method for raytrace programs

Program adjustments to increase the accuracy of the diffraction-based encircled energy analysis algorithms of the optical design computer programs ACCOS-V and SYNOPSYS are proposed. It is noted that the erroneous algorithms are based on the incorrect assumption that all the energy in a diffraction point spread function is contained within a circle of finite radius. Using these adjustments, more accurate encircled energy results are obtained for circles of radii less than or equal to the 100 percent boundary.