The structural, electronic and elastic properties of Rb As systems （RbAs in NaP, LiAs and AuCu structures, RbAs2 in the MgCu2 structure, Rb3As in NaaAs, Cu3P and Li3Bi structures, and Rb5As4 in the A5B4 structure） a...The structural, electronic and elastic properties of Rb As systems （RbAs in NaP, LiAs and AuCu structures, RbAs2 in the MgCu2 structure, Rb3As in NaaAs, Cu3P and Li3Bi structures, and Rb5As4 in the A5B4 structure） are investigated with the generalized gradient approximation in tile frame of density functional theory. The lattice parameters, cohesive energies, formation energies, bulk moduli and the first derivatives of the bulk moduli （to fit Murnaghan＇s equation of state） of the considered structures are calculated and reasonable agreement is obtained. In addition, the phase transition pressures are also predicted. The electronic band structures, the partial densities of states corresponding to the band structures and the charge density distributions are presented and analysed. The second-order elastic constants based on the stress-strain method and other related quantities such as Young＇s modulus, the shear modulus, Poisson＇s ratio, sound velocities, the Debye temperature and shear anisotropy factors are also estimated.展开更多
As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution ...As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.展开更多
为提高邮轮建造物资物流管理水平,提出基于改进逼近理想解排序法(technique for order preference by similarity to an ideal solution,TOPSIS)与模糊贝叶斯网络的风险评估模型。采用工作分解结构-风险分解结构(work breakdown structu...为提高邮轮建造物资物流管理水平,提出基于改进逼近理想解排序法(technique for order preference by similarity to an ideal solution,TOPSIS)与模糊贝叶斯网络的风险评估模型。采用工作分解结构-风险分解结构(work breakdown structure-risk breakdown structure,WBS-RBS)全面识别物流各环节风险因素,引入改进TOPSIS剔除重要度较小的风险因素。根据事故树构建贝叶斯网络,结合梯形模糊数和Buckley法计算贝叶斯网络根节点的概率,利用其正反向推理对风险进行预测、诊断及重要度分析,找出关键风险,提出改进措施。选取国产首艘大型邮轮的暖通空调物资物流进行实证研究发现,该物资配送延迟发生概率较高,通过加强对第三方和供应商的监管和信息交互、提高计划准确性和仓储集配规范性等可快速降低风险。研究表明:该模型能有针对性地找出物流中的薄弱环节,为邮轮建造物资物流风险管理提供借鉴。展开更多
文摘The structural, electronic and elastic properties of Rb As systems （RbAs in NaP, LiAs and AuCu structures, RbAs2 in the MgCu2 structure, Rb3As in NaaAs, Cu3P and Li3Bi structures, and Rb5As4 in the A5B4 structure） are investigated with the generalized gradient approximation in tile frame of density functional theory. The lattice parameters, cohesive energies, formation energies, bulk moduli and the first derivatives of the bulk moduli （to fit Murnaghan＇s equation of state） of the considered structures are calculated and reasonable agreement is obtained. In addition, the phase transition pressures are also predicted. The electronic band structures, the partial densities of states corresponding to the band structures and the charge density distributions are presented and analysed. The second-order elastic constants based on the stress-strain method and other related quantities such as Young＇s modulus, the shear modulus, Poisson＇s ratio, sound velocities, the Debye temperature and shear anisotropy factors are also estimated.
基金funded by the NSFC Grant(52177213)supported through NSFC Committee of Chinathe foundation(2020A1414010346 and 2019622163008)supported through the Science and Technology Bureau of Guangdong Governmentsponsored by the Student Research Program(X202110561688)supported through South China University of Technology。
文摘As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.
文摘为提高邮轮建造物资物流管理水平,提出基于改进逼近理想解排序法(technique for order preference by similarity to an ideal solution,TOPSIS)与模糊贝叶斯网络的风险评估模型。采用工作分解结构-风险分解结构(work breakdown structure-risk breakdown structure,WBS-RBS)全面识别物流各环节风险因素,引入改进TOPSIS剔除重要度较小的风险因素。根据事故树构建贝叶斯网络,结合梯形模糊数和Buckley法计算贝叶斯网络根节点的概率,利用其正反向推理对风险进行预测、诊断及重要度分析,找出关键风险,提出改进措施。选取国产首艘大型邮轮的暖通空调物资物流进行实证研究发现,该物资配送延迟发生概率较高,通过加强对第三方和供应商的监管和信息交互、提高计划准确性和仓储集配规范性等可快速降低风险。研究表明:该模型能有针对性地找出物流中的薄弱环节,为邮轮建造物资物流风险管理提供借鉴。
