This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and gr...This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and graphs which supersede those given in Ame2016.The first table presents the recommended atomic mass values and their uncertainties.It is followed by a table of the influences of data on primary nuclides,a table of various reaction and decay energies,and finally,a series of graphs of separation and decay energies.The last section of this paper provides all input data references that were used in the Ame2020 and the Nubase2020 evaluations.展开更多
Dislocation structures in polycrystalline Ni 3Al alloy doped with palladium deformed at room temperature have been investigated by transmission electron microscopy. The structure consists mainly of dislocations dissoc...Dislocation structures in polycrystalline Ni 3Al alloy doped with palladium deformed at room temperature have been investigated by transmission electron microscopy. The structure consists mainly of dislocations dissociated into a /2〈011〉 super partials bounding an anti phase boundary (APB). Dislocations dissociated into a /3〈112〉 super Shockley partials bounding a superlattice intrinsic stacking fault (SISF) are also common debris. The majority of the SISFs are truncated loops, i.e. the partials bounding the SISF are of similar Burgers vector. These faulted loops are generated from APB coupled dislocations, according to a mechanism for formation of SISFs proposed by Suzuki et al , and recently modified by Chiba et al . The APB energies for {111} and {010} slip planes are measured to be 144±20 mJ/m 2 and 102±11 mJ/m 2 respectively, and the SISF energy has been estimated to be 12 mJ/m 2 in this alloy. It is concluded that the dislocation structure in Ni 74.5 Pd 2Al 23.5 alloy deformed at room temperature is similar to that in binary Ni 3Al, and the difference in fault energies between these two alloys is small. Thus, it seems unlikely that the enhancement of ductility of Ni 74.5 Pd 2Al 23.5 results from only such a small decrease of the ordering energy of the alloy. SISF bounding dislocations also have no apparent influence on the ductilization of Ni 74.5 Pd 2Al 23.5 alloy.展开更多
This paper is the second part of the new evaluation of atomic masses, AME2016. Using least-squares adjustments to all evaluated and accepted experimental data, described in Part I, we derive tables with numerical valu...This paper is the second part of the new evaluation of atomic masses, AME2016. Using least-squares adjustments to all evaluated and accepted experimental data, described in Part I, we derive tables with numerical values and graphs to replace those given in AME2012. The first table lists the recommended atomic mass values and their uncertainties. It is followed by a table of the influences of data on primary nuclides, a table of various reaction and decay energies, and finally, a series of graphs of separation and decay energies. The last section of this paper lists all references of the input data used in the AME2016 and the NUBASE2016 evaluations （first paper in this issue）.展开更多
A few multi-terminal direct current(MTDC)systems are in operation around the world today. However,MTDC grids overlaying their AC counterpart might a reality in a near future. The main drivers for constructing such dir...A few multi-terminal direct current(MTDC)systems are in operation around the world today. However,MTDC grids overlaying their AC counterpart might a reality in a near future. The main drivers for constructing such direct current grids are the large-scale integration of remote renewable energy resources into the existing alternative current(AC) grids, and the promotion and development of international energy markets through the socalled supergrids. This paper presents the most critical challenges and prospects for such emerging MTDC grids,along with a foreseeable technology development roadmap,with a particular focus on crucial control and operational issues that are associated with MTDC systems and grids.展开更多
Machine learning(ML)is becoming a new paradigm for scientific research in various research fields due to its exciting and powerful capability of modeling tools used for big-data processing tasks.In this review,we firs...Machine learning(ML)is becoming a new paradigm for scientific research in various research fields due to its exciting and powerful capability of modeling tools used for big-data processing tasks.In this review,we first briefly introduce the different methodologies used in ML algorithms and techniques.As a snapshot of many applications by ML,some selected applications are presented,especially for low-and intermediate-energy nuclear physics,which include topics on theoretical applications in nuclear structure,nuclear reactions,properties of nuclear matter,and experimental applications in event identification/reconstruction,complex system control,and firmware performance.Finally,we present a summary and outlook on the possible directions of ML use in low-intermediate energy nuclear physics and possible improvements in ML algorithms.展开更多
Due to the growing penetration of renewable energies(REs)in integrated energy system(IES),it is imperative to assess and reduce the negative impacts caused by the uncertain REs.In this paper,an unscented transformatio...Due to the growing penetration of renewable energies(REs)in integrated energy system(IES),it is imperative to assess and reduce the negative impacts caused by the uncertain REs.In this paper,an unscented transformation-based mean-standard(UT-MS)deviation model is proposed for the stochastic optimization of cost-risk for IES operation considering wind and solar power correlated.The unscented transformation(UT)sampling method is adopted to characterize the uncertainties of wind and solar power considering the correlated relationship between them.Based on the UT,a mean-standard(MS)deviation model is formulated to depict the trade-off between the cost and risk of stochastic optimization for the IES optimal operation problem.Then the UT-MS model is tackled by a multi-objective group search optimizer with adaptive covariance and Levy flights embedded with a multiple constraints handling technique(MGSO-ACL-CHT)to ensure the feasibility of Peratooptimal solutions.Furthermore,a decision-making method,improved entropy weight(IEW),is developed to select a final operation point from the set of Perato-optimal solutions.In order to verify the feasibility and efficiency of the proposed UT-MS model in dealing with the uncertainties of correlative wind and solar power,simulation studies are conducted on a test IES.Simulation results show that the UT-MS model is capable of handling the uncertainties of correlative wind and solar power within much less samples and less computational burden.Moreover,the MGSOACL-CHT and IEW are also demonstrated to be effective in solving the multi-objective UT-MS model of the IES optimal operation problem.展开更多
The share of voltage source converter(VSC)technology is increasing in conventional power systems,and it is penetrating into specific transportation systems such as electric vehicles,railways,and ships.Researchers are ...The share of voltage source converter(VSC)technology is increasing in conventional power systems,and it is penetrating into specific transportation systems such as electric vehicles,railways,and ships.Researchers are identifying feasible methods to improve the performance of railway electrification systems(RESs)by utilizing VSC-based medium-voltage direct current(MVDC)railways.The continuous motion of electric trains makes the catenary resistance a variable quantity,as compared to the traction substation(TSS),and affects the currentsharing behavior of the system.A modified droop control technique is proposed in this paper for VSC-based MVDC RES to provide more effective current-sharing while maintaining catenary voltages above the minimum allowable limit.The droop coefficient is selected through an exponential function based on the ratio between the concerned TSS current and the system average current.This enables small adjustments of droop values in less concerning marginal current deviations,and provides higher droop adjustments for large current deviations.Meanwhile,the catenary voltages are regulated by considering the voltage data at the midpoint between two TSSs,which experiences the lowest voltages owing to the larger distance from the TSSs.The proposed techniques are validated via simulations and experiments.展开更多
Exciton energies as a function of radii of quantum dots in the range of 5–35 ? are calculated based on effective mass approximation model with the B-spline technique and compared with experimental and other theoretic...Exciton energies as a function of radii of quantum dots in the range of 5–35 ? are calculated based on effective mass approximation model with the B-spline technique and compared with experimental and other theoretical data for the CdS dots. This method leads to accurate and fast convergent exciton energy, which are in good agreement with experimental data in the whole confinement regime. The effect of penetration of wave function from the inside to the outside of the dots and the effect of dielectric constants are taken into account. The magnitudes of dynamical parameters are discussed. It is found that the different materials surrounding the CdS quantum dot affect not only the potential energy and Coulomb interaction energy of the system, but also the effective masses. The comparison shows that the effective mass approximation model can describe very well the quantum size effects observed experimentally on the exciton ground state energy.展开更多
This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for whic...This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for which any experimental information is known were considered. NUSASE2016 covers all data published by October 2016 in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new data and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2016, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides （TNN） were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.展开更多
Mozambique is doing well in its implementation of renewable energies (green energies), and this is a positive move as it sees to the protection of the environment, reduction of the emission of greenhouse gases, and th...Mozambique is doing well in its implementation of renewable energies (green energies), and this is a positive move as it sees to the protection of the environment, reduction of the emission of greenhouse gases, and the reduction of the country’s reliance on foreign fuels which are expensive and an economic burden on a country with an extremely high poverty index in Africa. Green energies like hydropower, solar energy and biomass are already in use with biomass leading, followed by hydropower. This paper explores and analyses the use of hydropower and biomass in Mozambique with the focus being on the extent of their use in the country and the impacts associated with their use. It also aims to look at policies that have been implemented to promote the use of these renewable sources of energy, and it discusses the success of the implementation of these policies and if they have helped in making the use of biomass and hydropower sustainable. The environmental impact of the use of green energies is minimum if compared to fossil fuels but this paper aims to show that there is concern in their use, especially the use of Biomass as there is little consideration being given to its environmental footprint. Mozambique has great potential for hydropower and bioenergy, but potential does not depict the reality as there are several issues to consider before the implementation of such in a developing country like Mozambique and this work explores the existence of issues that affect or hinder the growth and the sustainability of the use Biomass and Hydropower, and this is crucial in policy revision and implementation.展开更多
The explosive technological improvement of photovoltaic systems as well as the necessity of populations to come to less expensive energy sources, that have led to an implosion at the level of solar panel manufacturers...The explosive technological improvement of photovoltaic systems as well as the necessity of populations to come to less expensive energy sources, that have led to an implosion at the level of solar panel manufacturers. This causes a large flow of these equipments to developing countries where the need is high, without any quality control. That conducted an experimental investigation on the performance characteristics of a 250 wp monocrystalline silicon photovoltaic module in other to check the verification and quality control. Most of these PV panels which often have missing informations are manufactured and tested in places that are inadequate for our environmental and meteorological conditions. Also, their influences on the stability of internal parameters were evaluated in order to optimize their performance. The results obtained at maximum illumination (1000 w/m<sup>2</sup>) confirmed those produced by the manufacturer. The analysis of these characteristics showed that the illumination and the temperature (meteorological factors) influenced at most the stability of the internal characteristics of the module in the sense that the maximum power increased very rapidly beyond 750 w/m<sup>2</sup> but a degradation of performance was accentuated for a temperature of the solar cells exceeding 50°C. The degradation coefficients were evaluated at -0.0864 V/°C for the voltage and at -1.6248 w/°C for the power. The 10° inclination angle of the solar panel proved to be ideal for optimizing overall efficiency in practical situations.展开更多
Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)C...Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)U.However,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific research.In this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such calculations.Additionally,we investigated the energy dependence of independent yields to select important products.Furthermore,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)U.Given the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific research.The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U fission.In this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.展开更多
In current report,the structural,magnetic,and thermoelectric properties of RE doped MgPm_(2)X_(4)(X=S,Se) spinels were investigated.The energy difference in ferromagnetic and antiferromagnetic states reveals the stabi...In current report,the structural,magnetic,and thermoelectric properties of RE doped MgPm_(2)X_(4)(X=S,Se) spinels were investigated.The energy difference in ferromagnetic and antiferromagnetic states reveals the stability of MgPm_(2)(S/Se)_(4) in the ferromagnetic states.The co mputation of enthalpy of formation also ascertains thermodynamic stability of crystal structure.Spin-dependent band structure and density of states analysis reveal ferromagnetic semiconducting character showing different electronic behavior in both spin channels.The room temperature ferromagnetism,spin polarization and Curie temperature are estimated from exchange energies analysis.In addition,exchange constants(N_(0)α and N_(0)β),exchange energy Δ_(x)(pd),crystal ifeld energy,and double exchange mechanism were studied to explore the magnetic response.Likewise,the electrical conductivity,thermal conductivity,Seebeck co-efficient,and power factor show effect on electrons spin and their potential for thermoelectric devices.展开更多
We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigati...We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigation of the ^(15)N(p,γ0)^(16)O reaction includes the consideration of ^(3)S_(1) resonances due to E1 transitions and the contribution of the ^(3)P_(1) scattering wave in the p+^(15)N channel due to the ^(3)P_(1)→^(3)P_(0)M1 transition.We calculated the astrophysical low-energy S-factor,and the extrapolated S(0)turned out to be within 34.7−40.4 keV·b.The important role of the asymptotic constant(AC)for the ^(15)N(p,γ0)16O process with interfering ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances is elucidated.A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed,and a reasonable agreement is found.The reaction rate is calculated and compared with the existing rates.It has negligible dependence on the variation of AC but shows a strong impact of the interference of ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances in reference to the CNO Gamow windows,especially at low temperatures.We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys.Rev.C.85,065810(2012).The reaction rate enhancement due to the cascade transitions is observed from T_(9)>0.3 and reaches the maximum factor~1.3 at T_(9)=1.3.We present the Gamow energy window and a comparison of rates for radiative proton capture reactions ^(12)N(p,γ)^(13)O,^(13)N(p,γ)^(14)O,^(14)N(p,γ)^(15)O,and ^(15)N(p,γ)^(16)O obtained in the framework of the MPCM and provide the temperature windows,prevalence,and significance of each process.展开更多
Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate energies.Researchers urgently need solutions to the...Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate energies.Researchers urgently need solutions to the dilemma of traditional particle identification methods.This study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate energies.Multiple intelligent algorithms,including XgBoost and TabNet,were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics(NIMROD-ISiS)and Geant4 simulation.Tree-based machine learning algorithms and deep learning algorithms e.g.TabNet show excellent performance and generalization ability.Adding additional data features besides energy deposition can improve the algorithm’s performance when the data distribution is nonuniform.Intelligent learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.展开更多
Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the ...Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett B 834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.展开更多
Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollu...Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.展开更多
Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those ...Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those resulting from the biomethanization of biomass now provide an opportunity in the world of farmers and breeders. The treatment of agro-pastoral residues by anaerobic digestion has been the subject of renewed interest in recent years, thanks in particular to the production of energy from biomass, not to mention the production of fertilizers from effluents. Expelled from the digesters. This method of transformation offers many environmental, socio-economic and agricultural interests. Indeed, the biogas obtained from organic matter allows, among other things, to cook, light houses, and produce electricity and heat. The objective of this study is to compare the construction techniques and costs of the biodigester models that exist in Senegal. There are many biodigesters, the choice of an installation depends on the available space and the nature of the soil. Several types of biodigester technologies are installed in Senegal. The GGC 2047 fixed dome, the RMB geomembrane and the BEG geomembrane. First we will describe the construction techniques of the modified GGC model fixed dome biodigester, then of the RMB model geomembrane and finally of the BEG model geomembrane.展开更多
基金This work is supported in part by the Strategic Priority Research Program of Chinese Academy of Sciences(CAS,Grant No.XDB34000000)the National Key Research and Development Program of China(Grant No.2016YFA0400504)the U.S.Department of Energy,Of-fice of Science,Office of Nuclear Physics,under Contract No.DE-AC02-06CH11357.
文摘This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and graphs which supersede those given in Ame2016.The first table presents the recommended atomic mass values and their uncertainties.It is followed by a table of the influences of data on primary nuclides,a table of various reaction and decay energies,and finally,a series of graphs of separation and decay energies.The last section of this paper provides all input data references that were used in the Ame2020 and the Nubase2020 evaluations.
文摘Dislocation structures in polycrystalline Ni 3Al alloy doped with palladium deformed at room temperature have been investigated by transmission electron microscopy. The structure consists mainly of dislocations dissociated into a /2〈011〉 super partials bounding an anti phase boundary (APB). Dislocations dissociated into a /3〈112〉 super Shockley partials bounding a superlattice intrinsic stacking fault (SISF) are also common debris. The majority of the SISFs are truncated loops, i.e. the partials bounding the SISF are of similar Burgers vector. These faulted loops are generated from APB coupled dislocations, according to a mechanism for formation of SISFs proposed by Suzuki et al , and recently modified by Chiba et al . The APB energies for {111} and {010} slip planes are measured to be 144±20 mJ/m 2 and 102±11 mJ/m 2 respectively, and the SISF energy has been estimated to be 12 mJ/m 2 in this alloy. It is concluded that the dislocation structure in Ni 74.5 Pd 2Al 23.5 alloy deformed at room temperature is similar to that in binary Ni 3Al, and the difference in fault energies between these two alloys is small. Thus, it seems unlikely that the enhancement of ductility of Ni 74.5 Pd 2Al 23.5 results from only such a small decrease of the ordering energy of the alloy. SISF bounding dislocations also have no apparent influence on the ductilization of Ni 74.5 Pd 2Al 23.5 alloy.
基金supported in part by the National Key Program for S&T Research and Development (Contract No. 2016YFA0400504)the Major State Basic Research Development Program of China (Contract No. 2013CB834401)+3 种基金supported by the U.S. Department of Energy, Office of Science,Office of Nuclear Physics,under Contract No.DE-AC0206CH11357the support from the China Scholarship Council,grant No. 201404910496the support of “RIKEN Pioneering Project Funding” from the Riken projectthe support of “Light of West China Program” of Chinese Academy of Sciences
文摘This paper is the second part of the new evaluation of atomic masses, AME2016. Using least-squares adjustments to all evaluated and accepted experimental data, described in Part I, we derive tables with numerical values and graphs to replace those given in AME2012. The first table lists the recommended atomic mass values and their uncertainties. It is followed by a table of the influences of data on primary nuclides, a table of various reaction and decay energies, and finally, a series of graphs of separation and decay energies. The last section of this paper lists all references of the input data used in the AME2016 and the NUBASE2016 evaluations （first paper in this issue）.
文摘A few multi-terminal direct current(MTDC)systems are in operation around the world today. However,MTDC grids overlaying their AC counterpart might a reality in a near future. The main drivers for constructing such direct current grids are the large-scale integration of remote renewable energy resources into the existing alternative current(AC) grids, and the promotion and development of international energy markets through the socalled supergrids. This paper presents the most critical challenges and prospects for such emerging MTDC grids,along with a foreseeable technology development roadmap,with a particular focus on crucial control and operational issues that are associated with MTDC systems and grids.
基金supported by the National Natural Science Foundation of China(Grant Nos.11875070,11875323,12275359,11875125,12147219,U2032145,11705163,11790320,11790323,11790325,11975032,11835001,11935001,11890710,12147101,11835002,11705031,and 11961141003)the National Key R&D Program of China(Grant Nos.2018YFA0404404,2018YFA0404403,and 2020YFE0202001)+3 种基金the Continuous Basic Scientific Research Project(Grant No.WDJC-2019-13)the funding of China Institute of Atomic Energy(Grant No.YZ222407001301)the Leading Innovation Project of the China National Nuclear Corporation(Grant Nos.LC192209000701,and LC202309000201)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)。
文摘Machine learning(ML)is becoming a new paradigm for scientific research in various research fields due to its exciting and powerful capability of modeling tools used for big-data processing tasks.In this review,we first briefly introduce the different methodologies used in ML algorithms and techniques.As a snapshot of many applications by ML,some selected applications are presented,especially for low-and intermediate-energy nuclear physics,which include topics on theoretical applications in nuclear structure,nuclear reactions,properties of nuclear matter,and experimental applications in event identification/reconstruction,complex system control,and firmware performance.Finally,we present a summary and outlook on the possible directions of ML use in low-intermediate energy nuclear physics and possible improvements in ML algorithms.
基金supported by the State Key Program of National Natural Science Foundation of China(No.51437006)the Fundamental Research Funds for the Central Universities and the China Postdoctoral Science Foundation(No.2017M622690).
文摘Due to the growing penetration of renewable energies(REs)in integrated energy system(IES),it is imperative to assess and reduce the negative impacts caused by the uncertain REs.In this paper,an unscented transformation-based mean-standard(UT-MS)deviation model is proposed for the stochastic optimization of cost-risk for IES operation considering wind and solar power correlated.The unscented transformation(UT)sampling method is adopted to characterize the uncertainties of wind and solar power considering the correlated relationship between them.Based on the UT,a mean-standard(MS)deviation model is formulated to depict the trade-off between the cost and risk of stochastic optimization for the IES optimal operation problem.Then the UT-MS model is tackled by a multi-objective group search optimizer with adaptive covariance and Levy flights embedded with a multiple constraints handling technique(MGSO-ACL-CHT)to ensure the feasibility of Peratooptimal solutions.Furthermore,a decision-making method,improved entropy weight(IEW),is developed to select a final operation point from the set of Perato-optimal solutions.In order to verify the feasibility and efficiency of the proposed UT-MS model in dealing with the uncertainties of correlative wind and solar power,simulation studies are conducted on a test IES.Simulation results show that the UT-MS model is capable of handling the uncertainties of correlative wind and solar power within much less samples and less computational burden.Moreover,the MGSOACL-CHT and IEW are also demonstrated to be effective in solving the multi-objective UT-MS model of the IES optimal operation problem.
基金partly supported by‘‘the Open Project of National Rail Transit Electrification and Automation Engineering Technique Research Center’’(No.NEEC-2017-A03)partly supported by‘‘the Fundamental Research Funds for the Central Universities’’(No.2682017CX041).
文摘The share of voltage source converter(VSC)technology is increasing in conventional power systems,and it is penetrating into specific transportation systems such as electric vehicles,railways,and ships.Researchers are identifying feasible methods to improve the performance of railway electrification systems(RESs)by utilizing VSC-based medium-voltage direct current(MVDC)railways.The continuous motion of electric trains makes the catenary resistance a variable quantity,as compared to the traction substation(TSS),and affects the currentsharing behavior of the system.A modified droop control technique is proposed in this paper for VSC-based MVDC RES to provide more effective current-sharing while maintaining catenary voltages above the minimum allowable limit.The droop coefficient is selected through an exponential function based on the ratio between the concerned TSS current and the system average current.This enables small adjustments of droop values in less concerning marginal current deviations,and provides higher droop adjustments for large current deviations.Meanwhile,the catenary voltages are regulated by considering the voltage data at the midpoint between two TSSs,which experiences the lowest voltages owing to the larger distance from the TSSs.The proposed techniques are validated via simulations and experiments.
文摘Exciton energies as a function of radii of quantum dots in the range of 5–35 ? are calculated based on effective mass approximation model with the B-spline technique and compared with experimental and other theoretical data for the CdS dots. This method leads to accurate and fast convergent exciton energy, which are in good agreement with experimental data in the whole confinement regime. The effect of penetration of wave function from the inside to the outside of the dots and the effect of dielectric constants are taken into account. The magnitudes of dynamical parameters are discussed. It is found that the different materials surrounding the CdS quantum dot affect not only the potential energy and Coulomb interaction energy of the system, but also the effective masses. The comparison shows that the effective mass approximation model can describe very well the quantum size effects observed experimentally on the exciton ground state energy.
基金This work has been undertaken with the efidorsement of the IUPAP Commission on Symbols, Units, Nomenclature, Atomic Masses and Fundamental Constants （SUNAMCO）.
文摘This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for which any experimental information is known were considered. NUSASE2016 covers all data published by October 2016 in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new data and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2016, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides （TNN） were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.
文摘Mozambique is doing well in its implementation of renewable energies (green energies), and this is a positive move as it sees to the protection of the environment, reduction of the emission of greenhouse gases, and the reduction of the country’s reliance on foreign fuels which are expensive and an economic burden on a country with an extremely high poverty index in Africa. Green energies like hydropower, solar energy and biomass are already in use with biomass leading, followed by hydropower. This paper explores and analyses the use of hydropower and biomass in Mozambique with the focus being on the extent of their use in the country and the impacts associated with their use. It also aims to look at policies that have been implemented to promote the use of these renewable sources of energy, and it discusses the success of the implementation of these policies and if they have helped in making the use of biomass and hydropower sustainable. The environmental impact of the use of green energies is minimum if compared to fossil fuels but this paper aims to show that there is concern in their use, especially the use of Biomass as there is little consideration being given to its environmental footprint. Mozambique has great potential for hydropower and bioenergy, but potential does not depict the reality as there are several issues to consider before the implementation of such in a developing country like Mozambique and this work explores the existence of issues that affect or hinder the growth and the sustainability of the use Biomass and Hydropower, and this is crucial in policy revision and implementation.
文摘The explosive technological improvement of photovoltaic systems as well as the necessity of populations to come to less expensive energy sources, that have led to an implosion at the level of solar panel manufacturers. This causes a large flow of these equipments to developing countries where the need is high, without any quality control. That conducted an experimental investigation on the performance characteristics of a 250 wp monocrystalline silicon photovoltaic module in other to check the verification and quality control. Most of these PV panels which often have missing informations are manufactured and tested in places that are inadequate for our environmental and meteorological conditions. Also, their influences on the stability of internal parameters were evaluated in order to optimize their performance. The results obtained at maximum illumination (1000 w/m<sup>2</sup>) confirmed those produced by the manufacturer. The analysis of these characteristics showed that the illumination and the temperature (meteorological factors) influenced at most the stability of the internal characteristics of the module in the sense that the maximum power increased very rapidly beyond 750 w/m<sup>2</sup> but a degradation of performance was accentuated for a temperature of the solar cells exceeding 50°C. The degradation coefficients were evaluated at -0.0864 V/°C for the voltage and at -1.6248 w/°C for the power. The 10° inclination angle of the solar panel proved to be ideal for optimizing overall efficiency in practical situations.
基金Supported by the National Natural Science Foundation of China(12075105)the NSFC-Nuclear Technology Innovation Joint Fund(U2167203)+1 种基金the Major Science and Technology Projects of Gansu Province(22ZD6GB020)the Fundamental Research Funds for the Central Universities of China(lzujbky-2022-ey14,Izujbky-2022-kb07)。
文摘Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)U.However,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific research.In this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such calculations.Additionally,we investigated the energy dependence of independent yields to select important products.Furthermore,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)U.Given the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific research.The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U fission.In this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.
基金funded by the Princess Nourah bint Abdulrahman University Researchers Supporting Project(PNURSP2023R29)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabiathe Deanship of Scientific Research at King Khalid University,SaudiArabia for funding this work through Large Groups Project(L.R.G.P2/431/44)。
文摘In current report,the structural,magnetic,and thermoelectric properties of RE doped MgPm_(2)X_(4)(X=S,Se) spinels were investigated.The energy difference in ferromagnetic and antiferromagnetic states reveals the stability of MgPm_(2)(S/Se)_(4) in the ferromagnetic states.The co mputation of enthalpy of formation also ascertains thermodynamic stability of crystal structure.Spin-dependent band structure and density of states analysis reveal ferromagnetic semiconducting character showing different electronic behavior in both spin channels.The room temperature ferromagnetism,spin polarization and Curie temperature are estimated from exchange energies analysis.In addition,exchange constants(N_(0)α and N_(0)β),exchange energy Δ_(x)(pd),crystal ifeld energy,and double exchange mechanism were studied to explore the magnetic response.Likewise,the electrical conductivity,thermal conductivity,Seebeck co-efficient,and power factor show effect on electrons spin and their potential for thermoelectric devices.
基金the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259174)。
文摘We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigation of the ^(15)N(p,γ0)^(16)O reaction includes the consideration of ^(3)S_(1) resonances due to E1 transitions and the contribution of the ^(3)P_(1) scattering wave in the p+^(15)N channel due to the ^(3)P_(1)→^(3)P_(0)M1 transition.We calculated the astrophysical low-energy S-factor,and the extrapolated S(0)turned out to be within 34.7−40.4 keV·b.The important role of the asymptotic constant(AC)for the ^(15)N(p,γ0)16O process with interfering ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances is elucidated.A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed,and a reasonable agreement is found.The reaction rate is calculated and compared with the existing rates.It has negligible dependence on the variation of AC but shows a strong impact of the interference of ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances in reference to the CNO Gamow windows,especially at low temperatures.We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys.Rev.C.85,065810(2012).The reaction rate enhancement due to the cascade transitions is observed from T_(9)>0.3 and reaches the maximum factor~1.3 at T_(9)=1.3.We present the Gamow energy window and a comparison of rates for radiative proton capture reactions ^(12)N(p,γ)^(13)O,^(13)N(p,γ)^(14)O,^(14)N(p,γ)^(15)O,and ^(15)N(p,γ)^(16)O obtained in the framework of the MPCM and provide the temperature windows,prevalence,and significance of each process.
基金This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34030000)the National Key Research and Development Program of China(No.2022YFA1602404)+1 种基金the National Natural Science Foundation(No.U1832129)the Youth Innovation Promotion Association CAS(No.2017309).
文摘Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate energies.Researchers urgently need solutions to the dilemma of traditional particle identification methods.This study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate energies.Multiple intelligent algorithms,including XgBoost and TabNet,were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics(NIMROD-ISiS)and Geant4 simulation.Tree-based machine learning algorithms and deep learning algorithms e.g.TabNet show excellent performance and generalization ability.Adding additional data features besides energy deposition can improve the algorithm’s performance when the data distribution is nonuniform.Intelligent learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.
基金the National Key R&D Program of China(No.2023YFA1606503)the National Natural Science Foundation of China(Nos.12035011,11975167,11947211,11905103,11881240623,and 11961141003).
文摘Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett B 834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.
文摘Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.
文摘Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those resulting from the biomethanization of biomass now provide an opportunity in the world of farmers and breeders. The treatment of agro-pastoral residues by anaerobic digestion has been the subject of renewed interest in recent years, thanks in particular to the production of energy from biomass, not to mention the production of fertilizers from effluents. Expelled from the digesters. This method of transformation offers many environmental, socio-economic and agricultural interests. Indeed, the biogas obtained from organic matter allows, among other things, to cook, light houses, and produce electricity and heat. The objective of this study is to compare the construction techniques and costs of the biodigester models that exist in Senegal. There are many biodigesters, the choice of an installation depends on the available space and the nature of the soil. Several types of biodigester technologies are installed in Senegal. The GGC 2047 fixed dome, the RMB geomembrane and the BEG geomembrane. First we will describe the construction techniques of the modified GGC model fixed dome biodigester, then of the RMB model geomembrane and finally of the BEG model geomembrane.
