Based on Mohr-Coulomb （M-C） criterion, the parameters of Druker-Prager （D-P） criterion for geomaterial were determined under non-associated flow rule, and thus a new D-P type criterion was presented. Two assumptio...Based on Mohr-Coulomb （M-C） criterion, the parameters of Druker-Prager （D-P） criterion for geomaterial were determined under non-associated flow rule, and thus a new D-P type criterion was presented. Two assumptions were employed during the derivation： 1） principal strains by M-C model and D-P model are equal, and 2） the material is under plane strain condition. Based on the analysis of the surface on rt plane, it is found that the proposed D-P type criterion is better than the D-P criterion with M-C circumscribed circle or M-C inscribed circle, and is applicable for stress Lode angle less than zero. By comparing the predicted results with the test data of sand under plane strain condition and other D-P criteria, the proposed criterion is verified and agrees well with the test data, which is further proved to be better than other D--P type criteria in certain range of Lode angle. The criterion was compiled into a finite difference package FLAC3D by user-subroutine, and was used to analyze the stability of a slope by strength reduction method. The predicted slope safety factor from the proposed criterion agrees well with that by Spencer method, and it is more accurate than that from classic D-P criteria.展开更多
Quantum dots comprise a type of quantum impurity system. The entanglement and co- herence of quantum states are significantly influenced by the strong electron-electron interactions among impurities and their dissipat...Quantum dots comprise a type of quantum impurity system. The entanglement and co- herence of quantum states are significantly influenced by the strong electron-electron interactions among impurities and their dissipative coupling with the surrounding environment. Competition between many-body effects and transfer couplings plays an important role in determining the entanglement among localized impurity spins. In this work, we employ the hierarchical-equations-of-rnotion approach to explore the entanglement of a strongly correlated double quantum dots system. The relation between the total system entropy and those of subsystems is also investigated.展开更多
With the increasing popularity of the Internet and mobile Internet, the Virtual Community （VC） is becoming an important medium for person-to-person communication. To realise the potential of the VC, it is neces- sar...With the increasing popularity of the Internet and mobile Internet, the Virtual Community （VC） is becoming an important medium for person-to-person communication. To realise the potential of the VC, it is neces- sary to cultivate within it good group cohesion and vitality. Using empirical and experimental research methods, this study explores the ef- fect of users＇ trust in the VC Platform （VCP） on group cohesion and vitality and how brand and perceived privacy security can affect us- ers＇ trust in the VC. The research results indi- cate that the brand of the VCP can directly af- fect users＇ trust in the VC, and can also influe- nce it indirectly through users＇ perceived pri- vacy protection and perceived security protec- tion. Further, this study also confu＇ms that the performance of the VC （group cohesion and vitality） is significantly affected by users＇ trust in the VC. The results of this study can provide theoretical guidance for internet companies to maintain and enhance the value of VCs.展开更多
It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform.Through the numerical method,a new tandem wings hybrid airship w...It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform.Through the numerical method,a new tandem wings hybrid airship with both higher utility value and economy efficiency was obtained and its total performance and technical parameters were analyzed in detail.In order to further improve the lift-drag characteristics,we implemented the optimization design for aerodynamic configuration of tandem wings hybrid airship via the response surface method.The results indicate that the tandem wings hybrid airship has considerable volume efficiency and higher aerodynamic characteristics.After optimization,the lift-drag ratio of this hybrid airship was increased by 6.08%.In a given gross lift condition,tandem wings hybrid airship may provide more payload and specific productivity.Furthermore,the size of tandem airship is smaller so the demand for skin flexible materials can be reduced.Results of this study could serve as a new approach to designing buoyancy-lifting integrated hybrid airship.展开更多
基金Project(2010B14814) supported by the Fundamental Research Funds for the Central Universities of ChinaProject(200801133) supported by the Ministry of Water Resources of China for Public Welfare ProfessionProject(50809023) supported by the National Natural Science Foundation of China
文摘Based on Mohr-Coulomb （M-C） criterion, the parameters of Druker-Prager （D-P） criterion for geomaterial were determined under non-associated flow rule, and thus a new D-P type criterion was presented. Two assumptions were employed during the derivation： 1） principal strains by M-C model and D-P model are equal, and 2） the material is under plane strain condition. Based on the analysis of the surface on rt plane, it is found that the proposed D-P type criterion is better than the D-P criterion with M-C circumscribed circle or M-C inscribed circle, and is applicable for stress Lode angle less than zero. By comparing the predicted results with the test data of sand under plane strain condition and other D-P criteria, the proposed criterion is verified and agrees well with the test data, which is further proved to be better than other D--P type criteria in certain range of Lode angle. The criterion was compiled into a finite difference package FLAC3D by user-subroutine, and was used to analyze the stability of a slope by strength reduction method. The predicted slope safety factor from the proposed criterion agrees well with that by Spencer method, and it is more accurate than that from classic D-P criteria.
基金supported by the Ministry of Science and Technology of China(No.2016YFA0400900 and No.2016YFA0200600)the National Natural Science Foundation of China(No.21573202 and No.21633006)the Fundamental Research Funds for the Central Universities(No.2340000074)
文摘Quantum dots comprise a type of quantum impurity system. The entanglement and co- herence of quantum states are significantly influenced by the strong electron-electron interactions among impurities and their dissipative coupling with the surrounding environment. Competition between many-body effects and transfer couplings plays an important role in determining the entanglement among localized impurity spins. In this work, we employ the hierarchical-equations-of-rnotion approach to explore the entanglement of a strongly correlated double quantum dots system. The relation between the total system entropy and those of subsystems is also investigated.
基金supported by the National Natural Science Foundation of China under Grants No.71201011,No.71301106,No.71103021the Ministry of Education in China under Grants No.13YJA630084,No.13YJC630034,No.20120005120001
文摘With the increasing popularity of the Internet and mobile Internet, the Virtual Community （VC） is becoming an important medium for person-to-person communication. To realise the potential of the VC, it is neces- sary to cultivate within it good group cohesion and vitality. Using empirical and experimental research methods, this study explores the ef- fect of users＇ trust in the VC Platform （VCP） on group cohesion and vitality and how brand and perceived privacy security can affect us- ers＇ trust in the VC. The research results indi- cate that the brand of the VCP can directly af- fect users＇ trust in the VC, and can also influe- nce it indirectly through users＇ perceived pri- vacy protection and perceived security protec- tion. Further, this study also confu＇ms that the performance of the VC （group cohesion and vitality） is significantly affected by users＇ trust in the VC. The results of this study can provide theoretical guidance for internet companies to maintain and enhance the value of VCs.
基金supported by the National High-Tech Research and Development Program of China (Grant No. 863-2007AA11Z243)Foundation for Basic Research of Northwestern Polytechnic University (Grant No.JC-201103)
文摘It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform.Through the numerical method,a new tandem wings hybrid airship with both higher utility value and economy efficiency was obtained and its total performance and technical parameters were analyzed in detail.In order to further improve the lift-drag characteristics,we implemented the optimization design for aerodynamic configuration of tandem wings hybrid airship via the response surface method.The results indicate that the tandem wings hybrid airship has considerable volume efficiency and higher aerodynamic characteristics.After optimization,the lift-drag ratio of this hybrid airship was increased by 6.08%.In a given gross lift condition,tandem wings hybrid airship may provide more payload and specific productivity.Furthermore,the size of tandem airship is smaller so the demand for skin flexible materials can be reduced.Results of this study could serve as a new approach to designing buoyancy-lifting integrated hybrid airship.
