The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and t...The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output predictions.The quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the TBRE.However,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists.展开更多
In random-interaction ensembles, the electric quadrupole moments(Q) and magnetic moments(μ) of the Iπ = 11/2-isomers of the Cd isotopes predominantly exhibit a linear correlation with the neutron numbers,correspondi...In random-interaction ensembles, the electric quadrupole moments(Q) and magnetic moments(μ) of the Iπ = 11/2-isomers of the Cd isotopes predominantly exhibit a linear correlation with the neutron numbers,corresponding to the recently emphasized linear Q and μsystematics in realistic nuclear systems. Although the seniority scheme enhances such predominance(more essentially for μ), the configuration mixing due to quadrupole-like and δ-force-like proton-neutron(pn) interactions is responsible for the linear Q and μ systematics,respectively, in realistic nuclear system, as well as randominteraction ensembles.展开更多
By creating and analyzing two dimensional gas temperature and abundance maps of the RGH 80 compact galaxy group with high-quality Chandra data,we detect a high-abundance ( 0.7 Z⊙) arc,where the metal abundance is s...By creating and analyzing two dimensional gas temperature and abundance maps of the RGH 80 compact galaxy group with high-quality Chandra data,we detect a high-abundance ( 0.7 Z⊙) arc,where the metal abundance is significantly higher than the surrounding regions by 0.3Z⊙.This structure shows tight spatial correlations with the member galaxy PGC 046529,as well as with the arm-like feature identified on the X-ray image in the previous work of Randall et al.(2009).Since no apparent signature of AGN activity is found to be associated with PGC 046529 in multi-band observations,and the gas temperature,metallicity,and mass of the high-abundance arc resemble those of the ISM of typical early-type galaxies,we conclude that this high-abundance structure is the remnant of the ISM of PGC 046529,which was stripped out of the galaxy by ram pressure stripping due to the motion of PGC 046529 in RGH 80.This novel case shows that ram pressure stripping can work as efficiently in the metal enrichment process in galaxy groups as it can in galaxy clusters.展开更多
We study ten galaxy groups and clusters suggested in the literature to be "fossil systems(FSs)"based on Chandra observations. According to the M(500)- T and LX- T relations, the gas properties of FSs are not phy...We study ten galaxy groups and clusters suggested in the literature to be "fossil systems(FSs)"based on Chandra observations. According to the M(500)- T and LX- T relations, the gas properties of FSs are not physically distinct from ordinary galaxy groups or clusters. We also first study the f(gas, 2500)- T relation and find that the FSs exhibit the same trend as ordinary systems. The gas densities of FSs within 0.1r200 are - 10^-3cm^-3, which is the same order of magnitude as galaxy clusters. The entropies within 0.1r200(S(0.1r200)) of FSs are systematically lower than those in ordinary galaxy groups, which is consistent with previous reports, but we find their S(0.1r200)- T relation is more similar to galaxy clusters. The derived mass profiles of FSs are consistent with the Navarro, Frenk and White model in(0.1- 1)(r200), and the relation between scale radius rs and characteristic mass density δc indicates self-similarity of dark matter halos of FSs. The ranges of rs and δc for FSs are also close to those of galaxy clusters. Therefore, FSs share more common characteristics with galaxy clusters. The special birth place of the FS makes it a distinct type of galaxy system.展开更多
We present a study of a fossil cluster,SDSS J0150–1005(z 0.364),with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric...We present a study of a fossil cluster,SDSS J0150–1005(z 0.364),with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent merger.According to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±11.The central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar temperatures.Our results indicate that SDSS J0150–1005 formed during an early epoch.展开更多
By performing a two dimensional spectral analysis on the galaxy group NGC 533 with high-quality Chandra data, we find that the metal abundance distribution in this group is anisotropic. In the area around 2.5′ from t...By performing a two dimensional spectral analysis on the galaxy group NGC 533 with high-quality Chandra data, we find that the metal abundance distribution in this group is anisotropic. In the area around 2.5′ from the center, we find two concentrations of high abundance structures, in which the abundances are significantly higher than their surrounding regions at the 90% confidence level. We find that the total iron mass in these two regions agrees with the iron mass synthesized in the central dominant galaxy in n 19+0.08 Gyr. The double-sided configuration of the high abun- 0.03 dance structure, together with the point-like radio emission in the center suggests that the abundance structures could have been transported from the center to their present positions by active galactic nucleus (AGN) activity. We further calculate the energy required for transport, and find that it could have been supplied during an AGN period. However, considering that this group is reported to have experienced a recent merger, the possibility that this merger is responsible for the abundance structures still cannot be excluded.展开更多
The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role....The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.展开更多
基金supported by the National Natural Science Foundation of China Youth Fund(12105234)。
文摘The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output predictions.The quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the TBRE.However,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists.
基金supported by the National Natural Science Foundation of China(Nos.11647059 and 11305151)Research Fund for the Doctoral Program of the Southwest University of Science and Technology(No.14zx7102)Education Reform Project of the Southwest University of Science and Technology(No.17xn0102)
文摘In random-interaction ensembles, the electric quadrupole moments(Q) and magnetic moments(μ) of the Iπ = 11/2-isomers of the Cd isotopes predominantly exhibit a linear correlation with the neutron numbers,corresponding to the recently emphasized linear Q and μsystematics in realistic nuclear systems. Although the seniority scheme enhances such predominance(more essentially for μ), the configuration mixing due to quadrupole-like and δ-force-like proton-neutron(pn) interactions is responsible for the linear Q and μ systematics,respectively, in realistic nuclear system, as well as randominteraction ensembles.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10673008,10878001 and 10973010)the Ministry of Science and Technology of China (Grant No. 2009CB824900/2009CB24904)the Ministry of Education of China (the NCET Program)
文摘By creating and analyzing two dimensional gas temperature and abundance maps of the RGH 80 compact galaxy group with high-quality Chandra data,we detect a high-abundance ( 0.7 Z⊙) arc,where the metal abundance is significantly higher than the surrounding regions by 0.3Z⊙.This structure shows tight spatial correlations with the member galaxy PGC 046529,as well as with the arm-like feature identified on the X-ray image in the previous work of Randall et al.(2009).Since no apparent signature of AGN activity is found to be associated with PGC 046529 in multi-band observations,and the gas temperature,metallicity,and mass of the high-abundance arc resemble those of the ISM of typical early-type galaxies,we conclude that this high-abundance structure is the remnant of the ISM of PGC 046529,which was stripped out of the galaxy by ram pressure stripping due to the motion of PGC 046529 in RGH 80.This novel case shows that ram pressure stripping can work as efficiently in the metal enrichment process in galaxy groups as it can in galaxy clusters.
基金supported by the Research Fund for the Doctoral Program of the Southwest University of Science and Technology (No. 14zx7102)
文摘We study ten galaxy groups and clusters suggested in the literature to be "fossil systems(FSs)"based on Chandra observations. According to the M(500)- T and LX- T relations, the gas properties of FSs are not physically distinct from ordinary galaxy groups or clusters. We also first study the f(gas, 2500)- T relation and find that the FSs exhibit the same trend as ordinary systems. The gas densities of FSs within 0.1r200 are - 10^-3cm^-3, which is the same order of magnitude as galaxy clusters. The entropies within 0.1r200(S(0.1r200)) of FSs are systematically lower than those in ordinary galaxy groups, which is consistent with previous reports, but we find their S(0.1r200)- T relation is more similar to galaxy clusters. The derived mass profiles of FSs are consistent with the Navarro, Frenk and White model in(0.1- 1)(r200), and the relation between scale radius rs and characteristic mass density δc indicates self-similarity of dark matter halos of FSs. The ranges of rs and δc for FSs are also close to those of galaxy clusters. Therefore, FSs share more common characteristics with galaxy clusters. The special birth place of the FS makes it a distinct type of galaxy system.
基金Supported by the National Natural Science Foundation of China(Grant Nos. 10878001, 10973010 and 11125313)the National Basic Research Program of China (973 Program+2 种基金 Grant Nos. 2009CB824900 and 2009CB824904)the Shanghai Science and Technology Commission (Program of Shanghai Subject Chief Scientist Grant Nos. 12XD1406200 and 11DZ2260700)
文摘We present a study of a fossil cluster,SDSS J0150–1005(z 0.364),with high spatial resolution based on the imaging spectroscopic analysis of Chandra observations.The Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent merger.According to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±11.The central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar temperatures.Our results indicate that SDSS J0150–1005 formed during an early epoch.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10878001,10973010,and 11125313)the National Basic Research Program of China (973 Program+1 种基金Grant Nos.2009CB824900 and 2009CB824904)Shanghai Jiao Tong University Innovation Fund For Postgraduates
文摘By performing a two dimensional spectral analysis on the galaxy group NGC 533 with high-quality Chandra data, we find that the metal abundance distribution in this group is anisotropic. In the area around 2.5′ from the center, we find two concentrations of high abundance structures, in which the abundances are significantly higher than their surrounding regions at the 90% confidence level. We find that the total iron mass in these two regions agrees with the iron mass synthesized in the central dominant galaxy in n 19+0.08 Gyr. The double-sided configuration of the high abun- 0.03 dance structure, together with the point-like radio emission in the center suggests that the abundance structures could have been transported from the center to their present positions by active galactic nucleus (AGN) activity. We further calculate the energy required for transport, and find that it could have been supplied during an AGN period. However, considering that this group is reported to have experienced a recent merger, the possibility that this merger is responsible for the abundance structures still cannot be excluded.
基金This study was financially supported by the National Natural Science Foundation of China(Nos.52006057,51906097 and 11904324)the Fundamental Research Funds for the Central Universities(Nos.531119200237 and 541109010001)the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body at Hunan University(No.52175013).
文摘The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.