The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and ele...The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.展开更多
The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and ele...The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.展开更多
Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotati...Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotating rectangle and hexagon scaterers on the gaps are studied, respectively. The results show that the gaps can be substantially opened and tuned by rotating the scatterers. This approach should be helpful in designing magnonic crystals with desired gaps.展开更多
The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the an...The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the annealed one. The dynamically uniaxial compression behavior of the material is tested using the split Hopkinson pressure bar(SHPB) with temperature and strain rate ranging from 297 to 1073 K and500 to 3000 s^(-1), respectively, and a phenomenological plastic flow stress model is developed to describe the mechanical behavior of the material. The material is found to present noticeable temperature sensitivity and weak strain-rate sensitivity. The construction of the plastic flow stress model has two steps. Firstly, three univariate stress functions, taking plastic strain, plastic strain rate and temperature as independent variable, respectively, are proposed by fixing the other two variables. Then, as the three univariate functions describe the special cases of flow stress behavior under various conditions, the principle of stress compatibility is adopted to obtain the complete flow stress function. The numerical results show that the proposed plastic flow stress model is more suitable for the rotating band material than the existing well-known models.展开更多
Properties of the four rotation bands, ^157Er（1,2） and ^15SEr（1,2）, at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO（5） （or SU（5）） sym...Properties of the four rotation bands, ^157Er（1,2） and ^15SEr（1,2）, at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the 7-ray energies and the dynamical moments of inertia in the rotation bands in ^157 Er and ^158 Er at ultrahigh spin are obtained. We theoretically predict that the competition between the anti-pairing and pairing effects may exist in ^157 Er（1,2） and ^158Et（2） bands states. In ^158Er（1） band state, the favourepairing effects may exist and the SO（5） （or SU（5）） symmetry play a dominant role. There may be sphere coexisting with headecupole deformed in ^158Et（1） rotation band state.展开更多
Ru-based superconductor LaRu_(2)As_(2) has been discovered exhibiting the highest critical temperature of ~ 7.8 K among iron-free transition metal pnictides with the ThCr_(2)Si_(2)-type crystal structure. However, mic...Ru-based superconductor LaRu_(2)As_(2) has been discovered exhibiting the highest critical temperature of ~ 7.8 K among iron-free transition metal pnictides with the ThCr_(2)Si_(2)-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu_(2)As_(2). Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of ~ 1.0 me V. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.展开更多
This paper suggests the asymmetric-plastic theory of crystalline solids concerning the plastic rotation of crystal. The deformation of crystalline solids undergoes three microprocesses, lattice distortion, slip over a...This paper suggests the asymmetric-plastic theory of crystalline solids concerning the plastic rotation of crystal. The deformation of crystalline solids undergoes three microprocesses, lattice distortion, slip over active crystallographic planes and the rotation- of the crystal. In the asymmetric-plastic theory of crystal suggested, the corotational rates of symmetric Cauchy stress and moment stress correspond to the rates of elastic strain and the gradient of the rotational rate of the crystal respectively. The Schmid yield condition and Prager's consistency condition incorporating antisymmetric stress are formulated. Then the asymmetric-plastic model of crystalline solids is applied for the investigation of the onset of kink band by a standard stability analysis. The orientation of the kink band is perpendicular to the primary slip system. The width of the kink band is the function of the ''characteristic length'' of the microstructure of metal materials.展开更多
Transition energies of three triaxial superdeformed bands in 86Zr were fitted by the power-series expansion of spin I in odd powers of rotationalfrequeney ψ and by the two-parameter expression for rotational spectra....Transition energies of three triaxial superdeformed bands in 86Zr were fitted by the power-series expansion of spin I in odd powers of rotationalfrequeney ψ and by the two-parameter expression for rotational spectra. Level spins of these bands were assigned by means of the least-squares fits.展开更多
The rigid-rotor with a q-deformed moment of inertia is introduced to describe the nuclear rotational spectra.With the representations of quantum algebra,the normal deformed and superdeformed bands are naturally differ...The rigid-rotor with a q-deformed moment of inertia is introduced to describe the nuclear rotational spectra.With the representations of quantum algebra,the normal deformed and superdeformed bands are naturally differentiated by softness.The yrast normal deformed bands in rare earth and actinium regions,as well as the yrast superdeformed bands in A-190 and 150 regions are investigated.The calculated results agree with experimental data qualitatively well,and the values of the parameters are physically reasonable.This indicates that the fixed deformation,the stretching effect and the many body statistics effect are three possible dominant factors to govern nuclear rotational bands.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
In the N=88,90 region,a strong negative drive of γ deformation is generatedby the second lowest positive signature vi<sub>13/2</sub> quasiparticle orbital.In contrast,thelowest positive-parity and negativ...In the N=88,90 region,a strong negative drive of γ deformation is generatedby the second lowest positive signature vi<sub>13/2</sub> quasiparticle orbital.In contrast,thelowest positive-parity and negative-parity orbitals in this region exhibit positive drivesin the γ deformation toward oblate shapes.Replacing one of these with the negativedrive orbital strengthens the collectivity for the side band configurations at very highspins.展开更多
Experimental estimate values of the n-p interaction between the odd protonand the aligning neutron pairs for odd proton nuclei in the first band crossing region areextracted based on the experimental quasi-particle ro...Experimental estimate values of the n-p interaction between the odd protonand the aligning neutron pairs for odd proton nuclei in the first band crossing region areextracted based on the experimental quasi-particle routhians.The reliability of thismethod and the relation between the anomalous band crossing and the neutron-protoninteraction are discussed.展开更多
Anomalous delay of neutron AB crossing in rotational band based onh<sub>9</sub>/<sub>2</sub>1/2[541]proton state for odd-proton rare earth nuclei is interpreted as shape driv-ing effect.Compari...Anomalous delay of neutron AB crossing in rotational band based onh<sub>9</sub>/<sub>2</sub>1/2[541]proton state for odd-proton rare earth nuclei is interpreted as shape driv-ing effect.Comparisons of TRS/CSM calculations with experimental results are dis-cussed.展开更多
文摘The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.
文摘The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.
基金supported by the National Natural Science Foundation of China(Grant Nos.11264028 and 11072104)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Grant No.2012MS0114)the School Scientific Research Funds of Inner Mongolia Normal University of China(Grant Nos.2013YJRC007 and 2013ZRYB19)
文摘Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotating rectangle and hexagon scaterers on the gaps are studied, respectively. The results show that the gaps can be substantially opened and tuned by rotating the scatterers. This approach should be helpful in designing magnonic crystals with desired gaps.
基金the support from National Natural Science Foundation of China (Grant Nos. 11702137 and U2141246)。
文摘The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the annealed one. The dynamically uniaxial compression behavior of the material is tested using the split Hopkinson pressure bar(SHPB) with temperature and strain rate ranging from 297 to 1073 K and500 to 3000 s^(-1), respectively, and a phenomenological plastic flow stress model is developed to describe the mechanical behavior of the material. The material is found to present noticeable temperature sensitivity and weak strain-rate sensitivity. The construction of the plastic flow stress model has two steps. Firstly, three univariate stress functions, taking plastic strain, plastic strain rate and temperature as independent variable, respectively, are proposed by fixing the other two variables. Then, as the three univariate functions describe the special cases of flow stress behavior under various conditions, the principle of stress compatibility is adopted to obtain the complete flow stress function. The numerical results show that the proposed plastic flow stress model is more suitable for the rotating band material than the existing well-known models.
基金National Natural Science Foundation of China under Grant No.10475026the Natural Science Foundation of Zhejiang Province under Grant No.KY607518
文摘Properties of the four rotation bands, ^157Er（1,2） and ^15SEr（1,2）, at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the 7-ray energies and the dynamical moments of inertia in the rotation bands in ^157 Er and ^158 Er at ultrahigh spin are obtained. We theoretically predict that the competition between the anti-pairing and pairing effects may exist in ^157 Er（1,2） and ^158Et（2） bands states. In ^158Er（1） band state, the favourepairing effects may exist and the SO（5） （or SU（5）） symmetry play a dominant role. There may be sphere coexisting with headecupole deformed in ^158Et（1） rotation band state.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62488201 and 52072401)the National Key R&D Program of China(Grant No.2019YFA0308500)+1 种基金the Chinese Academy of Sciences(Grant No.YSBR-003)the Innovation Program of Quantum Science and Technology(Grant No.2021ZD0302700)。
文摘Ru-based superconductor LaRu_(2)As_(2) has been discovered exhibiting the highest critical temperature of ~ 7.8 K among iron-free transition metal pnictides with the ThCr_(2)Si_(2)-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu_(2)As_(2). Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of ~ 1.0 me V. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.
文摘This paper suggests the asymmetric-plastic theory of crystalline solids concerning the plastic rotation of crystal. The deformation of crystalline solids undergoes three microprocesses, lattice distortion, slip over active crystallographic planes and the rotation- of the crystal. In the asymmetric-plastic theory of crystal suggested, the corotational rates of symmetric Cauchy stress and moment stress correspond to the rates of elastic strain and the gradient of the rotational rate of the crystal respectively. The Schmid yield condition and Prager's consistency condition incorporating antisymmetric stress are formulated. Then the asymmetric-plastic model of crystalline solids is applied for the investigation of the onset of kink band by a standard stability analysis. The orientation of the kink band is perpendicular to the primary slip system. The width of the kink band is the function of the ''characteristic length'' of the microstructure of metal materials.
文摘Transition energies of three triaxial superdeformed bands in 86Zr were fitted by the power-series expansion of spin I in odd powers of rotationalfrequeney ψ and by the two-parameter expression for rotational spectra. Level spins of these bands were assigned by means of the least-squares fits.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19677102,19775044 and 19775044the Doctoral Unit Research Program Foundation of the State Education Commit tee of China(97035807)+1 种基金Centre of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator LanzhouNational Laboratory of Beijing Electron-Positron Collision.
文摘The rigid-rotor with a q-deformed moment of inertia is introduced to describe the nuclear rotational spectra.With the representations of quantum algebra,the normal deformed and superdeformed bands are naturally differentiated by softness.The yrast normal deformed bands in rare earth and actinium regions,as well as the yrast superdeformed bands in A-190 and 150 regions are investigated.The calculated results agree with experimental data qualitatively well,and the values of the parameters are physically reasonable.This indicates that the fixed deformation,the stretching effect and the many body statistics effect are three possible dominant factors to govern nuclear rotational bands.
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.
基金The projecet supported by National Natural Science Foundation of ChinaResearch at the University of Tennessee is supported by the Department of Energy through Contract Number DE-AS05-76ERO-4936.
文摘In the N=88,90 region,a strong negative drive of γ deformation is generatedby the second lowest positive signature vi<sub>13/2</sub> quasiparticle orbital.In contrast,thelowest positive-parity and negative-parity orbitals in this region exhibit positive drivesin the γ deformation toward oblate shapes.Replacing one of these with the negativedrive orbital strengthens the collectivity for the side band configurations at very highspins.
基金The project supported by China Science Foundation of Nuclear Industry
文摘Experimental estimate values of the n-p interaction between the odd protonand the aligning neutron pairs for odd proton nuclei in the first band crossing region areextracted based on the experimental quasi-particle routhians.The reliability of thismethod and the relation between the anomalous band crossing and the neutron-protoninteraction are discussed.
基金The project supported by China National Nuclear Corporation United Kindom Royal Society
文摘Anomalous delay of neutron AB crossing in rotational band based onh<sub>9</sub>/<sub>2</sub>1/2[541]proton state for odd-proton rare earth nuclei is interpreted as shape driv-ing effect.Comparisons of TRS/CSM calculations with experimental results are dis-cussed.
