Parallel numerical continuation of periodic responses of local nonlinear systems

Nonlinear Dynamics - The aim of this paper is to develop an efficient and robust parallel numerical continuation method for periodic solutions of local nonlinear systems. In this method, a...     

Primitive decompositions of Johnson graphs

A transitive decomposition of a graph is a partition of the edge set together with a group of automorphisms which transitively permutes the parts. In this paper we determine all transitive decompositions of the Johnson graphs such that the group preserving the partition is arc-transitive and acts primitively on the parts.     

中间逻辑中的良构范式

本文在中间逻辑中引入了良构范式的概念,为该类范式的研究提出了一个通用方法,并应用该方法证明了HT逻辑是存在一般蕴含范式的最弱中间逻辑,经典命题逻辑CPL是存在限制蕴含范式的仅有中间逻辑.     

不同合成方法对LiFePO4/C正极材料性能的影响

以磷酸亚铁为原料,分别采用磷酸亚铁与磷酸锂的直接合成法(直接法)和磷酸亚铁与原位合成磷酸锂的合成法(磷酸锂原位合成法)合成了橄榄石型LiFePO4/C复合正极材料.用X射线衍射(XRD)、扫描电镜(SEM)、以及充放电测试等方法对材料进行了结构表征和电化学性能测试.实验结果表明两种不同方法得到的样品具有橄榄石晶体结构....     

温和条件下对甲基苯磺酸铝高效催化一锅法合成β-氨基酮衍生物

室温条件下,对甲基苯磺酸铝可有效催化芳香酮、芳香醛和芳香胺的Mannich反应,三组分"一锅法"合成了一系列β-氨基酮衍生物.考察了溶剂及反应条件对产率的影响.反应结束后,催化剂经简单相分离可回收并多次重复使用,催化活性无明显下降.产物结构经IR,~1H NMR,元素分析进行表征.     

Ensemble-Based Relative Permeability Estimation Using B-Spline Model

A novel technique has been developed to implicitly estimate relative permeability by history matching the production data with the ensemble Kalman filter (EnKF) method. Water and oil relative permeability curves were approximated using the B-spline model, which has been modified to better represent the relative permeability curves. Compared to the existing implicit approaches, the newly developed technique did not require the use of the gradient of the objectives function and thus, was easy to implement. The newly developed technique has been validated by accurately evaluating relative permeability in a two-dimension synthetic heterogeneous reservoir. The case study showed that the estimated relative permeability was improved gradually as observation data were assimilated and that a good estimation of relative permeability curves can be effectively obtained. In this study, three estimation scenarios assimilating various types of observation data were examined and compared. It was also found that the oil relative permeability was sensitive to the oil production rate (OPR) data, as OPR was directly affected by oil relative permeability. On the other hand, water relative permeability was more sensitive to the bottomhole pressure data of the producers. Additionally, the production data, obtained prior to water breakthrough, contributed more to the estimation of the two-phase relative permeability curves.     

Some congruences for Andrews-Paule’s broken 2-diamond partitions

We prove two conjectures of Andrews and Paule [G.E. Andrews, P. Paule, MacMahon’s partition analysis XI: Broken diamonds and modular forms, Acta Arith. 126 (2007) 281-294] on congruences of broken k-diamond partitions.