为了进一步提高电能质量评估结果的精细化程度,提出了一种基于灰色关联度分析(Grey Relational Analysis,GRA)、二元语义(Binary Semantics,BS)和逼近理想解排序法(Technique for Order Preference by Similarity to an Ideal Solution,...为了进一步提高电能质量评估结果的精细化程度,提出了一种基于灰色关联度分析(Grey Relational Analysis,GRA)、二元语义(Binary Semantics,BS)和逼近理想解排序法(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)的电能质量综合评估方法。首先建立电能质量综合评估指标体系;其次利用G1法确定主观权重,采用指标相关法(Criteria Importance Though Intercrieria Correlation,CITIC)确定客观权重,并引入博弈论优化主客观综合权重系数,得到各项指标的综合权重;然后使用TOPSIS方法计算监测点指标数据与各指标对应的最优、最劣解之间的欧氏距离,并结合灰色关联度计算出相对贴近度,将其作为确定电能质量等级的判据并进行一次评估;最后利用二元语义法对一次评估结果中电能质量等级相同的监测点进行更为精细的二次评估。仿真算例结果验证该方法的有效性和精细性。展开更多
The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfe...The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfect and flow irrotational. A so-called new multi-domain method has been developed based on the fluid domain division by an analytical control surface surrounding bodies and the application of different methods adapted in the external and internal domains. In the analytical domain external to the control surface, the fundamental solution satisfying the linear boundary condition on the free surface associated with a point singularity （often called Green fimction and referred here as point solution） is applied to capture all wavy features of free-surface flows extending horizontally to infinity. Unlike classical studies in which the control surface is discretized, the unknown velocity potential and its normal derivatives are expressed by expansions of orthogonal elementary functions. The velocity potential associa- ted with each elementary distribution （elementary solutions） on the control surface can be obtained by performing multi-fold inte- grals in an analytical way. In the domain internal to the control surface containing the bodies, we could apply different methods like the Rankine source method based on the boundary integral equations for which the elementary solutions obtained in the external domain playing the role of Dirichlet-to-Neumarm operator close the problem.展开更多
文摘为了进一步提高电能质量评估结果的精细化程度,提出了一种基于灰色关联度分析(Grey Relational Analysis,GRA)、二元语义(Binary Semantics,BS)和逼近理想解排序法(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)的电能质量综合评估方法。首先建立电能质量综合评估指标体系;其次利用G1法确定主观权重,采用指标相关法(Criteria Importance Though Intercrieria Correlation,CITIC)确定客观权重,并引入博弈论优化主客观综合权重系数,得到各项指标的综合权重;然后使用TOPSIS方法计算监测点指标数据与各指标对应的最优、最劣解之间的欧氏距离,并结合灰色关联度计算出相对贴近度,将其作为确定电能质量等级的判据并进行一次评估;最后利用二元语义法对一次评估结果中电能质量等级相同的监测点进行更为精细的二次评估。仿真算例结果验证该方法的有效性和精细性。
文摘结合对称性破损(BS)方法,采用不同的密度泛函理论(DFT)对反铁磁性μ-1,3-N3-Ni(II)叠氮配合物[LNi2(N3)](Cl O4)2(L=pyrazolate)的磁特性进行了研究.结果显示,杂化密度泛函理论(HDFT)的计算结果与实验数据非常吻合,能够准确描述配合物的磁特性.磁轨道研究结果表明,配合物表现出较大的单占据轨道能量劈裂(0.93-0.99 e V),显示配合物的单占据轨道去简并化程度较大,且配合物中的2个磁通道(叠氮基、配体pyrazolate)中都分别存在有氮原子之间的p轨道重叠,这些都使得体系表现为反铁磁耦合作用.另外,配合物的磁性与叠氮桥和两金属离子间形成的二面角(τ,Ni-N-N-N-Ni)密切相关,τ从-55.38°逐渐变化到-1.5°的过程中,其反铁磁性逐渐增强,交换耦合常数(Jab)的绝对值逐渐增大,并在-11.95°处达到最大值(Jab=-151.02 cm-1).在此过程中,配合物中叠氮桥及其所连接的2个Ni离子与pyrazolate基配体L-中的2个桥原子N(4)、N(5)形成的七元环共平面性不断增强,即共平面性会诱导增强体系的反铁磁相互作用.
文摘The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfect and flow irrotational. A so-called new multi-domain method has been developed based on the fluid domain division by an analytical control surface surrounding bodies and the application of different methods adapted in the external and internal domains. In the analytical domain external to the control surface, the fundamental solution satisfying the linear boundary condition on the free surface associated with a point singularity （often called Green fimction and referred here as point solution） is applied to capture all wavy features of free-surface flows extending horizontally to infinity. Unlike classical studies in which the control surface is discretized, the unknown velocity potential and its normal derivatives are expressed by expansions of orthogonal elementary functions. The velocity potential associa- ted with each elementary distribution （elementary solutions） on the control surface can be obtained by performing multi-fold inte- grals in an analytical way. In the domain internal to the control surface containing the bodies, we could apply different methods like the Rankine source method based on the boundary integral equations for which the elementary solutions obtained in the external domain playing the role of Dirichlet-to-Neumarm operator close the problem.
