We employed random distributions and gradient descent methods for the Generator Coordinate Method(GCM)to identify effective basis wave functions,taking halo nuclei ^(6)He and ^(6)Li as examples.By comparing the ground...We employed random distributions and gradient descent methods for the Generator Coordinate Method(GCM)to identify effective basis wave functions,taking halo nuclei ^(6)He and ^(6)Li as examples.By comparing the ground state(0^(+))energy of ^(6)He and the excited state(0^(+))energy of 6 Li calculated with various random distributions and manually selected generation coordinates,we found that the heavy tail characteristic of the logistic distribution better describes the features of the halo nuclei.Subsequently,the Adam algorithm from machine learning was applied to optimize the basis wave functions,indicating that a limited number of basis wave functions can approximate the converged values.These results offer some empirical insights for selecting basis wave functions and contribute to the broader application of machine learning methods in predicting effective basis wave functions.展开更多
The existence of nanographene in cluster form is discussed in organic solvents. Theories are developed based on the columnlet, bundlet and droplet models describing the size-distribution functions. Phenomena present a...The existence of nanographene in cluster form is discussed in organic solvents. Theories are developed based on the columnlet, bundlet and droplet models describing the size-distribution functions. Phenomena present a unified explanation in the columnlet model in which free energy of Cgraphene involved in cluster is combined from a volume part proportional to the number of molecules n in cluster and a constant. The columnlet model enables describing distribution function of Cgraphene clusters by size. From purely geometrical considerations the columnlet （Cgraphene）, bundlet （single-wall carbon nanotube）, CNT （carbon nanotube）, SWNT （single-wall C-nanotube）, and carbon nanobud, CNB （carbon nanobud）） and droplet （fullerene） models predict dissimilar behaviours. The interaction-energy parameters of Cgraphene are taken from C60. An CNB behaviour or further is expected. The decay of solubility with rising temperature is smaller for Cgraphene than for SWNT and CNB and, furthermore, than for C60, in agreement with lesser numbers of units in Cgraphene clusters. The discrepancy between the experimental data of the heat of solution of fullerenes, CNTs, CNBs and graphenes is ascribed to the sharp concentration dependence of the heat of solution. The diffusion coefficient drops with temperature result greater for Cgraphene than CNB and SWNT than C60 corresponding to lesser number of units in clusters. The aggregates near （C60）13, SWNT/CNB7 and （Cgraphene）3 could be representative of the droplet, bundlet and columnlet models.展开更多
In this paper, a cluster model in particle flow code was used to simulate granite specimens after heat treatment under uniaxial compression. The results demonstrated that micro-cracks are randomly distributed in the s...In this paper, a cluster model in particle flow code was used to simulate granite specimens after heat treatment under uniaxial compression. The results demonstrated that micro-cracks are randomly distributed in the specimen when the temperature is below 300?C, and have partial coalescence when the temperature is up to 450?C, then form macro-cracks when the temperature is above 600?C. There is more inter-granular cracking than intra-granular cracking, and their ratio increases with increasing temperature.The micro-cracks are almost constant when the temperature decreases from 900?C to room temperature, except for quartz α–β phase transition temperature(573?C). The fracture evolution process is obviously affected by these cracks, especially at 600–900?C. Elevated temperature leads to easily developed displacement between the grains, and the capacity to store strain energy becomes weaker, corresponding to the plasticity of granite after heat treatment.展开更多
The chemisorption properties of N^18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures o...The chemisorption properties of N^18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K, and (high) temperature of 980 K. This meant that N^18O decomposed and recombined during the process of N2 desorption after N^18O was exposed. Analysis of thestable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO2(110) cluster modelshowed that there was clear preference for the Ti-NO orientation.展开更多
As a widely used measurement technique in rock mechanics,spatial correlation modeling of acoustic emission(AE)scattering signals is attracting increasing focus for describing mechanical behavior quantitatively.Unlike ...As a widely used measurement technique in rock mechanics,spatial correlation modeling of acoustic emission(AE)scattering signals is attracting increasing focus for describing mechanical behavior quantitatively.Unlike the statistical description of the spatial distribution of randomly generated AE signals,spatial correlation modeling is based mainly on short-range correlation considering the interrelationship of adjacent signals.As a new idea from percolation models,the covering strategy is used to build the most representative cube cluster,which corresponds to the critical scale at peak stress.Its modeling process of critical cube cluster depends strongly on the full connection of the main fracture network,and the corresponding cube for coverage is termed the critical cube.The criticality pertains to not only the transition of local-to-whole connection of the fracture network but also the increasing-to-decreasing transition of the deviatoric stress with an obvious stress drop in the brittle failure of granite.Determining a reasonable critical cube guarantees the best observation scale for investigating the failure process.Besides,the topological connection induces the geometric criticality of three descriptors,namely anisotropy,pore fraction,and specific surface area,which are evaluated separately and effectively.The results show that cluster modeling based on the critical cube is effective and has criticality in both topology and geometry,as well as the triaxial behavior.Furthermore,the critical cube length presents a high confidence probability of being correlated to the mineral particle size.Besides,its pore fraction of cube cluster is influenced strongly by the critical cube length and confining pressure.展开更多
The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model con...The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model containing seven octahedral cations was the smallest size to be employed to simulate other properties.The fact that the n＋ charge of cluster models containing n aluminum atoms can reflect electronic properties of anionic clay layer sheet.The bond lengths of clusters can be modified by terminating with or without OH-/H2O groups in terms of principle of bond order conservation.展开更多
The α-target semimicroscopic single folding potentials have been derived by folding a composite (repul-sive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. T...The α-target semimicroscopic single folding potentials have been derived by folding a composite (repul-sive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phe-nomenologicaly expressed using the Woods-Saxon form. Nine sets of measured experimental data of the 4He+12C and 4 He+16O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.展开更多
Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have ...Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have been investigated by employing DV - Xa method, in which different cluster models were adopted to calculate electron structure.It is proved that some regulations must be taken into ac- count in order to carry out alloy design calculation successfully,which are described in this paper in detail.展开更多
We investigate the ground-state rotational bands of nuclei with Z 〉 100 using cluster model proposed by Buck et al. [Phys. Rev. Left. 94 （2005） 202501]. The core-duster decomposition of each nucleus is determined b...We investigate the ground-state rotational bands of nuclei with Z 〉 100 using cluster model proposed by Buck et al. [Phys. Rev. Left. 94 （2005） 202501]. The core-duster decomposition of each nucleus is determined by the corresponding electric quadrupole transition strength B（E2 ： 2^＋ → 0^＋）. The theoretical spectra of fermium and nobelium isotopes are compared with available experimental data. Good agreement between model and data is obtained.展开更多
One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must ...One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(); (2) to find the right projection direction ; (3) to calculate projection characteristic value of the i th sample z-i, and (4) to draw comprehensive analysis on the basis of z-i. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.展开更多
In this study,a comprehensive investigation on different cluster configurations of the ~9Be nucleus is performed with a simple cluster approach.With this goal,the elastic scattering angular distributions of ~9Be by ^(...In this study,a comprehensive investigation on different cluster configurations of the ~9Be nucleus is performed with a simple cluster approach.With this goal,the elastic scattering angular distributions of ~9Be by ^(27)A1,^(28)Si,^(64)Zn,^(144)Sm,^(208)Pb,and ^(209)Bi target nuclei are reanalyzed for α + α + n,d + ~7Li,~3H + ~6Li,~3He + ~6He and n + ~8Be cluster configurations of the ~9Be projectile within the framework of the optical model.The theoretical results are compared with each other as well as the experimental data.The results provide an opportunity for a test of different cluster configurations in explaining the elastic scattering of^9Be nucleus.展开更多
The paper describes the development results on one-dimensional (1D) asymptotic model of the formation kinetics for the objects (clusters) of subnuclear (quark) and subatomic (nuclear) matters. A concept of the objects...The paper describes the development results on one-dimensional (1D) asymptotic model of the formation kinetics for the objects (clusters) of subnuclear (quark) and subatomic (nuclear) matters. A concept of the objects distribution density wave φ(a, t) in space of sizes a lies in the basis for analytical description of the processes under consideration. The proposed formalism makes it possible to describe in an adequate way the final outcomes of the well-known catastrophic phenomena in the world of elementary particles. Mass characteristics of different processes of approach to equilibrium in nuclear reactions are calculated.展开更多
The properties of the modified surface of SnO2(110) with benzoic acid (Y-C6H4-COOH: Y is para position relative to -COOH group) derivatives were investigated using density functional theory. Zehner et al. mentioned th...The properties of the modified surface of SnO2(110) with benzoic acid (Y-C6H4-COOH: Y is para position relative to -COOH group) derivatives were investigated using density functional theory. Zehner et al. mentioned that the modification of surface dipole moment made it possible to tune the work function of the system. The experiment of Ganzorig et al. showed that there was a linear relationship between the dipole moment of the binding molecule and the work function change of the system using the modified surface of indium-tin oxide (ITO) with some benzoic acid derivatives. To elucidate the relation between the dipole moment of the molecule and the work function change, we investigated the modified surface of SnO2(110) using Sn7O14 cluster model which was embedded in the fixed point charges. On the modification of the surface, benzoic acid derivatives were bound to SnO2 surface. By changing the terminal group of benzoic acid with H, Cl, F, CF3 and CCl3, the work function changed and the dipole moment of the binding molecules of the modified SnO2(110) were evaluated. The results showed that there was a linear relationship between the dipole moment of the binding molecules and the work function changed. From this relation, the average value of the dipole moments of Sn-OOC linkage at the surface was also evaluated.展开更多
Several criteria for determining self consistently the magnitude of point charges employed in the embedded cluster modeling of metal oxides have been proposed and investigated. Merits and demerits of these criteria ha...Several criteria for determining self consistently the magnitude of point charges employed in the embedded cluster modeling of metal oxides have been proposed and investigated. Merits and demerits of these criteria have been compared. Ab initio study has been performed to show the influence of the values of point charges chosen on the calculated electronic properties of the embedded MgO cluster. The calculation results demonstrate that the electronic properties of the embedded cluster are of great dependence on the magnitude of the embedding point charges; that the employment of the nominal charges, ±2.0, would cause overestimation of the crystal potential even in the case of the so called purely ionic oxide, MgO; and that certain requirements for the consistence between the embedded cluster and the embedding point charges should be reached. It is further found that errors for the calculated properties of the embedded cluster still exist with respect to those of bulk solid even in the case that self consistence in terms of charge, dipole moment, or electrostatic potential was met between the cut out cluster and the embedding point charges. As far as spherical expansion is performed upon the embedding point charges, which furnishes the embedding point charges with a continuous distribution of charge density, a global agreement is reached between the calculated properties of the embedded cluster model and those of the bulk solid.展开更多
Symplectic symmetry approach to clustering(SSAC)in atomic nuclei,recently proposed,is modified and further developed in more detail.It is firstly applied to the light two-cluster^(20)Ne+αsystem of^(24)Mg,the latter e...Symplectic symmetry approach to clustering(SSAC)in atomic nuclei,recently proposed,is modified and further developed in more detail.It is firstly applied to the light two-cluster^(20)Ne+αsystem of^(24)Mg,the latter exhibiting well developed low-energy K^(π)=0_(1)^(+),k^(π)=2_(1)^(+) and π^(π)=0_(1)^(-) rotational bands in its spectrum.A simple algebraic Hamiltonian,consisting of dynamical symmetry,residual and vertical mixing parts is used to describe these three lowest rotational bands of positive and negative parity in^(24)Mg.A good description of the excitation energies is obtained by considering only the SU(3)cluster states restricted to the stretched many-particle Hilbert subspace,built on the leading Pauli allowed SU(3)multiplet for the positive-and negative-parity states,respectively.The coupling to the higher cluster-model configurations allows us to describe the known low-lying experimentally observed B(E2)transition probabilities within and between the cluster states of the three bands under consideration without the use of an effective charge.展开更多
We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transition...We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transitions from the n^(13)B scattering states to the ground and first excited states of^(14)B are presented.The 1st resonance at Ex=1.275 MeV(1+)is revealed in both the cross-section and reaction rate.Within the variation in the asymptotic constant,a thermal cross-section interval of 5.1-8.9 mb is proposed.Based on the theoretical total cross-sections at energies of 0.01 eV to 5 MeV,we calculate the reaction rate in the temperature range of 0.01 to 10T9.The ignition T9 values of the^(13)B(n,γ0+1)^(14)B reaction depending on a neutron number density n_(n)of~10^(22)cm^(−3)are determined.The radiative neutron capture reaction rates on the boron^(10-13)B and carbon^(12-14)Сisotopes are compared.展开更多
It was supposed that, the nucleus was composed of α-cluster, pn-pair, and nn-pair. The reciprocity of the α-cluster, pn-pair, and nn-pair caused the regular change of the separating energy to separate the nn-pair in...It was supposed that, the nucleus was composed of α-cluster, pn-pair, and nn-pair. The reciprocity of the α-cluster, pn-pair, and nn-pair caused the regular change of the separating energy to separate the nn-pair in the exotic nuclei. The regular change was that the separating energy was high behind low to separate the nn-pair in the light and exotic nuclei. This phenomenon must had more profound physical meaning.展开更多
A cluster model is used to calculate electron energy-loss fine structures in crystal. The multiple-scattering self-consistent-field method is employed in the calculation. Our theoretical results of N near K-edge energ...A cluster model is used to calculate electron energy-loss fine structures in crystal. The multiple-scattering self-consistent-field method is employed in the calculation. Our theoretical results of N near K-edge energy loss fine structures in hexagonal GaN crystal are in good agreement with the experimental spectra. Future possible experiments in energy-filtered transmission electron microscopy (EFTEM) are discussed and proposed because our theoretical work can provide clear assignments for transmitted electrons with different energy losses.展开更多
The problem of the deuteron interaction with lithium nuclei,treated as a system of two coupled pointlike clusters,is formulated to calculate the cross sections of the d+Li reaction.The d+Li reaction mechanism is descr...The problem of the deuteron interaction with lithium nuclei,treated as a system of two coupled pointlike clusters,is formulated to calculate the cross sections of the d+Li reaction.The d+Li reaction mechanism is described using the Faddeev theory for the three-body problem of deuteron-nucleus interaction.This theory is slightly extended for calculation of the stripping processes ^6Li(d,p)^7Li,^7Li(d,p)^8 ,^6Li(d,n)^7 Be,and ^7Li(d,n)^8 Be,as well as fragmentation reactions yielding tritium,a-particles,and continuous neutrons and protons in the initial deuteron kineticenergy region Ed=0.5-20 MeV.The phase shifts found for d+^6Li and d+^7Li elastic scattering,as part of the simple optic model with a complex central potential,were used to find the cross sections for the 6^Li(d,yM)^8 and ^7Li(d,yE1)^9 Be radiation captures.The three-body dynamics role is also summarized to demonstrate its significant influence within the d+^7Li system.展开更多
Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from ...Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from 10^(-2)eV up to 5 MeV.The thermal cross-section σ_(th)=8.35mb is in good agreement with experimental data.We considered five resonances at the excitation energies E_(x)from 7.371 MeV up to 10.570 MeV corresponding to the following states with J^(π)(E_(x),MeV):3^(-)(7.371),2^(+)(7.542),3^(+)(9.4),2^(+)(9.56),and 3^(-)(10.570).The partial and total ^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rates are calculated at temperatures from 0.001 to 10 T_(9).Contrary to the available data,we propose that the rise in the reaction rate near factor five at T_(9)>1 is mainly due to the first 3^(-)(E_(R)=0.559 MeV)resonance.We foresee this contrast as arising from different model approaches.展开更多
基金supported by the National Key R&D Program of China(No.2023YFA1606701)the National Natural Science Foundation of China(Nos.12175042,11890710,11890714,12047514,12147101,and 12347106)+1 种基金Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030008)China National Key R&D Program(No.2022YFA1602402).
文摘We employed random distributions and gradient descent methods for the Generator Coordinate Method(GCM)to identify effective basis wave functions,taking halo nuclei ^(6)He and ^(6)Li as examples.By comparing the ground state(0^(+))energy of ^(6)He and the excited state(0^(+))energy of 6 Li calculated with various random distributions and manually selected generation coordinates,we found that the heavy tail characteristic of the logistic distribution better describes the features of the halo nuclei.Subsequently,the Adam algorithm from machine learning was applied to optimize the basis wave functions,indicating that a limited number of basis wave functions can approximate the converged values.These results offer some empirical insights for selecting basis wave functions and contribute to the broader application of machine learning methods in predicting effective basis wave functions.
文摘The existence of nanographene in cluster form is discussed in organic solvents. Theories are developed based on the columnlet, bundlet and droplet models describing the size-distribution functions. Phenomena present a unified explanation in the columnlet model in which free energy of Cgraphene involved in cluster is combined from a volume part proportional to the number of molecules n in cluster and a constant. The columnlet model enables describing distribution function of Cgraphene clusters by size. From purely geometrical considerations the columnlet （Cgraphene）, bundlet （single-wall carbon nanotube）, CNT （carbon nanotube）, SWNT （single-wall C-nanotube）, and carbon nanobud, CNB （carbon nanobud）） and droplet （fullerene） models predict dissimilar behaviours. The interaction-energy parameters of Cgraphene are taken from C60. An CNB behaviour or further is expected. The decay of solubility with rising temperature is smaller for Cgraphene than for SWNT and CNB and, furthermore, than for C60, in agreement with lesser numbers of units in Cgraphene clusters. The discrepancy between the experimental data of the heat of solution of fullerenes, CNTs, CNBs and graphenes is ascribed to the sharp concentration dependence of the heat of solution. The diffusion coefficient drops with temperature result greater for Cgraphene than CNB and SWNT than C60 corresponding to lesser number of units in clusters. The aggregates near （C60）13, SWNT/CNB7 and （Cgraphene）3 could be representative of the droplet, bundlet and columnlet models.
基金supported by the National Natural Science Foundation of Jiangsu Province of China for Distinguished Young Scholars (Grant BK20150005)the Fundamental Research Funds for the Central Universities (China University of Mining and Technology) (Grant 2014XT03)
文摘In this paper, a cluster model in particle flow code was used to simulate granite specimens after heat treatment under uniaxial compression. The results demonstrated that micro-cracks are randomly distributed in the specimen when the temperature is below 300?C, and have partial coalescence when the temperature is up to 450?C, then form macro-cracks when the temperature is above 600?C. There is more inter-granular cracking than intra-granular cracking, and their ratio increases with increasing temperature.The micro-cracks are almost constant when the temperature decreases from 900?C to room temperature, except for quartz α–β phase transition temperature(573?C). The fracture evolution process is obviously affected by these cracks, especially at 600–900?C. Elevated temperature leads to easily developed displacement between the grains, and the capacity to store strain energy becomes weaker, corresponding to the plasticity of granite after heat treatment.
文摘The chemisorption properties of N^18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K, and (high) temperature of 980 K. This meant that N^18O decomposed and recombined during the process of N2 desorption after N^18O was exposed. Analysis of thestable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO2(110) cluster modelshowed that there was clear preference for the Ti-NO orientation.
基金the National Natural Science Foundation of China(No.51504257)the State Key Research Development Program of China(No.2016YFC0600704)+1 种基金the Fund of Yueqi Outstanding Scholars(No.2018B051616)the Open Fund of the State Key Laboratory of Coal Mine Disaster Dynamics and Control(No.2011DA105287-FW201604).
文摘As a widely used measurement technique in rock mechanics,spatial correlation modeling of acoustic emission(AE)scattering signals is attracting increasing focus for describing mechanical behavior quantitatively.Unlike the statistical description of the spatial distribution of randomly generated AE signals,spatial correlation modeling is based mainly on short-range correlation considering the interrelationship of adjacent signals.As a new idea from percolation models,the covering strategy is used to build the most representative cube cluster,which corresponds to the critical scale at peak stress.Its modeling process of critical cube cluster depends strongly on the full connection of the main fracture network,and the corresponding cube for coverage is termed the critical cube.The criticality pertains to not only the transition of local-to-whole connection of the fracture network but also the increasing-to-decreasing transition of the deviatoric stress with an obvious stress drop in the brittle failure of granite.Determining a reasonable critical cube guarantees the best observation scale for investigating the failure process.Besides,the topological connection induces the geometric criticality of three descriptors,namely anisotropy,pore fraction,and specific surface area,which are evaluated separately and effectively.The results show that cluster modeling based on the critical cube is effective and has criticality in both topology and geometry,as well as the triaxial behavior.Furthermore,the critical cube length presents a high confidence probability of being correlated to the mineral particle size.Besides,its pore fraction of cube cluster is influenced strongly by the critical cube length and confining pressure.
基金supported by China University of Petroleum (East China) (grant 09CX04045A)
文摘The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model containing seven octahedral cations was the smallest size to be employed to simulate other properties.The fact that the n＋ charge of cluster models containing n aluminum atoms can reflect electronic properties of anionic clay layer sheet.The bond lengths of clusters can be modified by terminating with or without OH-/H2O groups in terms of principle of bond order conservation.
文摘The α-target semimicroscopic single folding potentials have been derived by folding a composite (repul-sive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phe-nomenologicaly expressed using the Woods-Saxon form. Nine sets of measured experimental data of the 4He+12C and 4 He+16O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.
文摘Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have been investigated by employing DV - Xa method, in which different cluster models were adopted to calculate electron structure.It is proved that some regulations must be taken into ac- count in order to carry out alloy design calculation successfully,which are described in this paper in detail.
基金The project supported by National Natural Science Foundation of China under Grant No. 10535010, the 973 State Key Basic Research Program of China under Grant No. G2000077400, the CAS Knowledge Innovation Project under Grant No. KJCX2-SW-N02, and the Research Fund for the Doctoral Program of Higher Education under Grant No. 20010284036.
文摘We investigate the ground-state rotational bands of nuclei with Z 〉 100 using cluster model proposed by Buck et al. [Phys. Rev. Left. 94 （2005） 202501]. The core-duster decomposition of each nucleus is determined by the corresponding electric quadrupole transition strength B（E2 ： 2^＋ → 0^＋）. The theoretical spectra of fermium and nobelium isotopes are compared with available experimental data. Good agreement between model and data is obtained.
文摘One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(); (2) to find the right projection direction ; (3) to calculate projection characteristic value of the i th sample z-i, and (4) to draw comprehensive analysis on the basis of z-i. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.
文摘In this study,a comprehensive investigation on different cluster configurations of the ~9Be nucleus is performed with a simple cluster approach.With this goal,the elastic scattering angular distributions of ~9Be by ^(27)A1,^(28)Si,^(64)Zn,^(144)Sm,^(208)Pb,and ^(209)Bi target nuclei are reanalyzed for α + α + n,d + ~7Li,~3H + ~6Li,~3He + ~6He and n + ~8Be cluster configurations of the ~9Be projectile within the framework of the optical model.The theoretical results are compared with each other as well as the experimental data.The results provide an opportunity for a test of different cluster configurations in explaining the elastic scattering of^9Be nucleus.
文摘The paper describes the development results on one-dimensional (1D) asymptotic model of the formation kinetics for the objects (clusters) of subnuclear (quark) and subatomic (nuclear) matters. A concept of the objects distribution density wave φ(a, t) in space of sizes a lies in the basis for analytical description of the processes under consideration. The proposed formalism makes it possible to describe in an adequate way the final outcomes of the well-known catastrophic phenomena in the world of elementary particles. Mass characteristics of different processes of approach to equilibrium in nuclear reactions are calculated.
文摘The properties of the modified surface of SnO2(110) with benzoic acid (Y-C6H4-COOH: Y is para position relative to -COOH group) derivatives were investigated using density functional theory. Zehner et al. mentioned that the modification of surface dipole moment made it possible to tune the work function of the system. The experiment of Ganzorig et al. showed that there was a linear relationship between the dipole moment of the binding molecule and the work function change of the system using the modified surface of indium-tin oxide (ITO) with some benzoic acid derivatives. To elucidate the relation between the dipole moment of the molecule and the work function change, we investigated the modified surface of SnO2(110) using Sn7O14 cluster model which was embedded in the fixed point charges. On the modification of the surface, benzoic acid derivatives were bound to SnO2 surface. By changing the terminal group of benzoic acid with H, Cl, F, CF3 and CCl3, the work function changed and the dipole moment of the binding molecules of the modified SnO2(110) were evaluated. The results showed that there was a linear relationship between the dipole moment of the binding molecules and the work function changed. From this relation, the average value of the dipole moments of Sn-OOC linkage at the surface was also evaluated.
文摘Several criteria for determining self consistently the magnitude of point charges employed in the embedded cluster modeling of metal oxides have been proposed and investigated. Merits and demerits of these criteria have been compared. Ab initio study has been performed to show the influence of the values of point charges chosen on the calculated electronic properties of the embedded MgO cluster. The calculation results demonstrate that the electronic properties of the embedded cluster are of great dependence on the magnitude of the embedding point charges; that the employment of the nominal charges, ±2.0, would cause overestimation of the crystal potential even in the case of the so called purely ionic oxide, MgO; and that certain requirements for the consistence between the embedded cluster and the embedding point charges should be reached. It is further found that errors for the calculated properties of the embedded cluster still exist with respect to those of bulk solid even in the case that self consistence in terms of charge, dipole moment, or electrostatic potential was met between the cut out cluster and the embedding point charges. As far as spherical expansion is performed upon the embedding point charges, which furnishes the embedding point charges with a continuous distribution of charge density, a global agreement is reached between the calculated properties of the embedded cluster model and those of the bulk solid.
文摘Symplectic symmetry approach to clustering(SSAC)in atomic nuclei,recently proposed,is modified and further developed in more detail.It is firstly applied to the light two-cluster^(20)Ne+αsystem of^(24)Mg,the latter exhibiting well developed low-energy K^(π)=0_(1)^(+),k^(π)=2_(1)^(+) and π^(π)=0_(1)^(-) rotational bands in its spectrum.A simple algebraic Hamiltonian,consisting of dynamical symmetry,residual and vertical mixing parts is used to describe these three lowest rotational bands of positive and negative parity in^(24)Mg.A good description of the excitation energies is obtained by considering only the SU(3)cluster states restricted to the stretched many-particle Hilbert subspace,built on the leading Pauli allowed SU(3)multiplet for the positive-and negative-parity states,respectively.The coupling to the higher cluster-model configurations allows us to describe the known low-lying experimentally observed B(E2)transition probabilities within and between the cluster states of the three bands under consideration without the use of an effective charge.
基金the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259174)。
文摘We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transitions from the n^(13)B scattering states to the ground and first excited states of^(14)B are presented.The 1st resonance at Ex=1.275 MeV(1+)is revealed in both the cross-section and reaction rate.Within the variation in the asymptotic constant,a thermal cross-section interval of 5.1-8.9 mb is proposed.Based on the theoretical total cross-sections at energies of 0.01 eV to 5 MeV,we calculate the reaction rate in the temperature range of 0.01 to 10T9.The ignition T9 values of the^(13)B(n,γ0+1)^(14)B reaction depending on a neutron number density n_(n)of~10^(22)cm^(−3)are determined.The radiative neutron capture reaction rates on the boron^(10-13)B and carbon^(12-14)Сisotopes are compared.
文摘It was supposed that, the nucleus was composed of α-cluster, pn-pair, and nn-pair. The reciprocity of the α-cluster, pn-pair, and nn-pair caused the regular change of the separating energy to separate the nn-pair in the exotic nuclei. The regular change was that the separating energy was high behind low to separate the nn-pair in the light and exotic nuclei. This phenomenon must had more profound physical meaning.
基金the National Natural Science Foundation of China ( Grant Nos.19874035, 59831020, 19734030), National 973 Project, National 863 Program, Climbing Project, The Ministry of Science and Technology of China, National High-Tec ICF Committee, the Ministry of
文摘A cluster model is used to calculate electron energy-loss fine structures in crystal. The multiple-scattering self-consistent-field method is employed in the calculation. Our theoretical results of N near K-edge energy loss fine structures in hexagonal GaN crystal are in good agreement with the experimental spectra. Future possible experiments in energy-filtered transmission electron microscopy (EFTEM) are discussed and proposed because our theoretical work can provide clear assignments for transmitted electrons with different energy losses.
基金The reported study was funded by RFBR,(20-02-00004)。
文摘The problem of the deuteron interaction with lithium nuclei,treated as a system of two coupled pointlike clusters,is formulated to calculate the cross sections of the d+Li reaction.The d+Li reaction mechanism is described using the Faddeev theory for the three-body problem of deuteron-nucleus interaction.This theory is slightly extended for calculation of the stripping processes ^6Li(d,p)^7Li,^7Li(d,p)^8 ,^6Li(d,n)^7 Be,and ^7Li(d,n)^8 Be,as well as fragmentation reactions yielding tritium,a-particles,and continuous neutrons and protons in the initial deuteron kineticenergy region Ed=0.5-20 MeV.The phase shifts found for d+^6Li and d+^7Li elastic scattering,as part of the simple optic model with a complex central potential,were used to find the cross sections for the 6^Li(d,yM)^8 and ^7Li(d,yE1)^9 Be radiation captures.The three-body dynamics role is also summarized to demonstrate its significant influence within the d+^7Li system.
基金Supported by the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259021)。
文摘Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from 10^(-2)eV up to 5 MeV.The thermal cross-section σ_(th)=8.35mb is in good agreement with experimental data.We considered five resonances at the excitation energies E_(x)from 7.371 MeV up to 10.570 MeV corresponding to the following states with J^(π)(E_(x),MeV):3^(-)(7.371),2^(+)(7.542),3^(+)(9.4),2^(+)(9.56),and 3^(-)(10.570).The partial and total ^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rates are calculated at temperatures from 0.001 to 10 T_(9).Contrary to the available data,we propose that the rise in the reaction rate near factor five at T_(9)>1 is mainly due to the first 3^(-)(E_(R)=0.559 MeV)resonance.We foresee this contrast as arising from different model approaches.
