针对传统路径路由方法在复杂网络中出现的负载不均衡,传输路径复杂等问题,提出一种基于软件定义网络(Software Defined Network,SDN)的跳数负载均衡策略(SDNHop Link Load Balancing,SDN-HLLB)。基于SDN对网络架构的全局查看能力,控制...针对传统路径路由方法在复杂网络中出现的负载不均衡,传输路径复杂等问题,提出一种基于软件定义网络(Software Defined Network,SDN)的跳数负载均衡策略(SDNHop Link Load Balancing,SDN-HLLB)。基于SDN对网络架构的全局查看能力,控制器对传输过程中的节点进行实时更新并计算,选出最优路径并进行数据传输。通过Mininet工具进行模拟,利用Networkx实现最短路径转发,结果表明SDN-HLLB可提高数据传输速率,实现网络链路负载均衡,满足用户在复杂环境中对传输速率要求。展开更多
The research involving the crystal structures and properties of uranyl carbonate minerals is essential in actinide environmental chemistry due to the fundamental role played by these minerals in the migration of actin...The research involving the crystal structures and properties of uranyl carbonate minerals is essential in actinide environmental chemistry due to the fundamental role played by these minerals in the migration of actinides from uranium deposits and nuclear waste repositories and in the investigation of accidental site contaminations.In this work,the crystal structure,hydrogen bonding network,X-ray diffraction pattern and mechanical properties of six important uranyl carbonate minerals,roubaultite(Cu_(2)[(UO_(2))_(3)(CO_(3))_(2)(OH)_(2)]·4H_(2)O),fontanite(Ca[(UO_(2))_(3)(CO_(3))_(2)(OH)_(2)]·6H_(2)O),sharpite(Ca[(UO_(2))_(3)(CO_(3))_(4)(OH)_(2)]·3H_(2)O),widenmannite(Pb_(2)[(UO_(2))(CO_(3))_(2)(OH)_(2)]),grimselite(K_(3)Na[(UO_(2))(CO_(3))_(3)]·H_(2)O)andčejkaite(Na_(4)[(UO_(2))(CO_(3))_(3)]),are investigated using first principles solid-state methods based in density functional theory.The determination of the positions of the hydrogen atoms in the unit cells of fontanite,sharpite and grimselite minerals,defining the hydrogen bonding network in their crystal structures,has not been feasible so far due to the low quality of their experimental X-ray diffraction patterns.The full crystal struc-tures of these minerals are obtained here and their hydrogen bonding networks are studied in detail.Furthermore,the experimental structures of roubaultite,widenmannite andčejkaite,obtained by refine-ment from X-ray diffraction data,are confirmed.In the six cases,the computed unit-cell parameters and the associated geometrical variables are in excellent agreement with the available experimental infor-mation.Furthermore,the X-ray diffraction patterns computed from the optimized structures are in satis-factory agreement with their experimental counterparts.The knowledge of the full crystal structures,being extraordinarily relevant for many scientific fields,is also extremely interesting because it opens the possibility of determining their physico-chemical properties using the first principles methodology.The measurement of these properties under safe conditions is very expensive and complicated due to the radiotoxicity of these minerals.In this paper,a large set of relevant mechanical properties of these min-erals are determined including their bulk,shear and Young moduli,the Poisson’s ratio,ductility,hardness and anisotropy indices and bulk modulus pressure derivatives.These properties have not been measured so far and,therefore,are predicted here.Four of these minerals,roubaultite,fontanite,sharpite and wide-mmannite,are highly anisotropic and exhibit negative mechanical phenomena under the effect of small external pressures.展开更多
文摘针对传统路径路由方法在复杂网络中出现的负载不均衡,传输路径复杂等问题,提出一种基于软件定义网络(Software Defined Network,SDN)的跳数负载均衡策略(SDNHop Link Load Balancing,SDN-HLLB)。基于SDN对网络架构的全局查看能力,控制器对传输过程中的节点进行实时更新并计算,选出最优路径并进行数据传输。通过Mininet工具进行模拟,利用Networkx实现最短路径转发,结果表明SDN-HLLB可提高数据传输速率,实现网络链路负载均衡,满足用户在复杂环境中对传输速率要求。
基金supported by the Ministry of Culture of the Czech Republic(long-term project DKRVO_(2)019–2023/1.Ⅱ.bNational Museum,00023272).
文摘The research involving the crystal structures and properties of uranyl carbonate minerals is essential in actinide environmental chemistry due to the fundamental role played by these minerals in the migration of actinides from uranium deposits and nuclear waste repositories and in the investigation of accidental site contaminations.In this work,the crystal structure,hydrogen bonding network,X-ray diffraction pattern and mechanical properties of six important uranyl carbonate minerals,roubaultite(Cu_(2)[(UO_(2))_(3)(CO_(3))_(2)(OH)_(2)]·4H_(2)O),fontanite(Ca[(UO_(2))_(3)(CO_(3))_(2)(OH)_(2)]·6H_(2)O),sharpite(Ca[(UO_(2))_(3)(CO_(3))_(4)(OH)_(2)]·3H_(2)O),widenmannite(Pb_(2)[(UO_(2))(CO_(3))_(2)(OH)_(2)]),grimselite(K_(3)Na[(UO_(2))(CO_(3))_(3)]·H_(2)O)andčejkaite(Na_(4)[(UO_(2))(CO_(3))_(3)]),are investigated using first principles solid-state methods based in density functional theory.The determination of the positions of the hydrogen atoms in the unit cells of fontanite,sharpite and grimselite minerals,defining the hydrogen bonding network in their crystal structures,has not been feasible so far due to the low quality of their experimental X-ray diffraction patterns.The full crystal struc-tures of these minerals are obtained here and their hydrogen bonding networks are studied in detail.Furthermore,the experimental structures of roubaultite,widenmannite andčejkaite,obtained by refine-ment from X-ray diffraction data,are confirmed.In the six cases,the computed unit-cell parameters and the associated geometrical variables are in excellent agreement with the available experimental infor-mation.Furthermore,the X-ray diffraction patterns computed from the optimized structures are in satis-factory agreement with their experimental counterparts.The knowledge of the full crystal structures,being extraordinarily relevant for many scientific fields,is also extremely interesting because it opens the possibility of determining their physico-chemical properties using the first principles methodology.The measurement of these properties under safe conditions is very expensive and complicated due to the radiotoxicity of these minerals.In this paper,a large set of relevant mechanical properties of these min-erals are determined including their bulk,shear and Young moduli,the Poisson’s ratio,ductility,hardness and anisotropy indices and bulk modulus pressure derivatives.These properties have not been measured so far and,therefore,are predicted here.Four of these minerals,roubaultite,fontanite,sharpite and wide-mmannite,are highly anisotropic and exhibit negative mechanical phenomena under the effect of small external pressures.
