## 2017年 第1期

2017, (1): 1-10. doi: 10.3969/j.issn.1000-5641.2017.01.001

2017, (1): 11-18. doi: 10.3969/j.issn.1000-5641.2017.01.002

2017, (1): 19-25. doi: 10.3969/j.issn.1000-5641.2017.01.003

k-边连通图在网络研究和图论研究中有着极其重要的地位.图论中有关2-,边连通图的命题很多, 它们刻画了2-,边连通的本质.本文给出17种关于2-边连通图的等价性命题,力图从不同角度深入理解、挖掘2-边连通图的本征,并从本文定义的2种新运算出发, 提出了新的有关2-边连通图的命题,并给出这些命题相互间的等价性证明.
2017, (1): 26-31. doi: 10.3969/j.issn.1000-5641.2017.01.004

A(G)表示G的邻接矩阵,Q(G)=D(G)+A(G)是G的无符号拉普拉斯矩阵,Q(G)的最大特征值是G的无符 号拉普拉斯谱半径. 在这篇文章中,我们分别确定了给定点连通度、给定块数和给定悬挂点数的图类中无符号拉普拉斯谱半径最大的图的结构.
2017, (1): 32-37. doi: 10.3969/j.issn.1000-5641.2017.01.005

2017, (1): 38-51. doi: 10.3969/j.issn.1000-5641.2017.01.006

A lot of empirical studies have demonstrated that Java software system is a kind of artificial complex network and its in-degree distribution obeys the power law, while out-degree distribution is lognormal. However, most experiment objects in these studies are Java development tools, such as JDK, log4j and Tomcat, and the type of data analyzed in dependence graph is limited, because they only consider some class dependence relationships and omit certain useful data types, like member variables and local variables. In this paper, we all useful dependence relationships between entities or modules on both class and function levels, and we further propose a novel method to transform a system network into a weighted directed graph. Comprehensive experiment results show that the in- and out-degree of 10 types of Java application systems mostly fit the power law distributions, and our proposed method to detect the scale-free feature of a weighted and directed network is effective in analyzing Java application systems.

2017, (1): 52-63. doi: 10.3969/j.issn.1000-5641.2017.01.007

2017, (1): 64-70. doi: 10.3969/j.issn.1000-5641.2017.01.008

2017, (1): 71-79. doi: 10.3969/j.issn.1000-5641.2017.01.009

Different thickness of Ni80Fe20 films are deposited on the Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons using RF (radio frequency) magnetron sputtering method. The magnetic properties and magneto impedance effect are measured and compared with as-cast Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons. The results show that the ribbon coated with 260 nm Ni80Fe20 layer achieves a much better performance than others, which produces a GMI (giant magneto-impedance) ratio of 33.0%. It is found that the surface of 260 nm Ni80Fe20 layer is smoother and the particle size is relatively smaller. The hysteresis loops of the ribbons with and without Ni80Fe20 coating layer are almost unchanged. However, the hysteresis loops of the Ni80Fe20 films sputtered onto glass substrate indicate the shift of anisotropy direction from parallel to normal to the surface as the thickness increases. The shifting will influence the magnetic exchange interaction between the amorphous ribbons and the Ni80Fe20 coating layers. The variation of GMI effect can be interpreted by the surface structure and magnetic exchange interaction.

2017, (1): 80-90. doi: 10.3969/j.issn.1000-5641.2017.01.010

2017, (1): 91-103,112. doi: 10.3969/j.issn.1000-5641.2017.01.011

2017, (1): 104-112. doi: 10.3969/j.issn.1000-5641.2017.01.012

2017, (1): 113-124. doi: 10.3969/j.issn.1000-5641.2017.01.013

2017, (1): 125-131. doi: 10.3969/j.issn.1000-5641.2017.01.014

2017, (1): 132-138. doi: 10.3969/j.issn.1000-5641.2017.01.0015

2017, (1): 133-139.