The commuting graphs of some subsets in the quaternion algebra over the ring of integers modulo <Emphasis Type="Italic">N</Emphasis>

Let R be an arbitrary ring, S be a subset of R, and Z(S) = {s ∈ S | sx = xs for every x ∈ S}. The commuting graph of S, denoted by Γ(S), is the graph with vertex set S \ Z(S) such that two different vertices x and y are adjacent if and only if xy = yx. In this paper, let I _n , N _n be the sets of all idempotents, nilpotent elements in the quaternion algebra ℤ _n [i, j, k], respectively. We completely determine Γ(I _n ) and Γ(N _n ). Moreover, it is proved that for n ≥ 2, Γ(I _n ) is connected if and only if n has at least two odd prime factors, while Γ(N _n ) is connected if and only if n ∈ 2, 2², p, 2p for all odd primes p.     

热电制冷模组热端散热器性能优化研究

针对实际项目热电制冷模组进行了三维数值模拟,对比分析断槽数不同的四种典型散热器在不同电流、翅片厚度、断槽宽度下的散热能力,得到了性能较佳的工况与散热器模型.结果 表明,随着电流增加,热电制冷模组冷面温度不断降低,当电流超过一定数值时,冷面温度趋于平衡,热面温度急剧上升.四类散热器中,断槽数为一的散热器散热能力较佳,并对...     

几种陶瓷和金属等离子喷涂层铸铁副的摩擦学特性研究

本文对等离子喷涂ZrO_2+MgO和Al_2O_3+40％ZrO_2陶瓷涂层、Mo+NiCrBSi(Ar/H_2)和Mo+NiCrBSi(N_2/H_2)混合粉末涂层,以及Mo+4％O_2渗氧涂层等的摩擦学特性进行了试验研究,测定了它们的抗咬合裁荷及其在边界润滑状态下的磨损率。结果表明,Al_2O_3+40％ZrO_2陶瓷涂层/铸铁副的抗咬合性能最好,在其轻度粘着的表面上形成了一层表面膜;Mo+NiCrBSi(N_2/H_2)金属涂层是一种实用性能较好的活塞环材料;在粘着磨损条件下,涂层材料的抗咬合性越好,与之配磨的铸铁材科的磨损率越低;涂层材料的抗咬合性与其本身的固有特性及孔隙率等有关。     

Characterizing the anticipating chaotic synchronization of RCL-shunted Josephson junctions

This study addresses the problem of anticipating synchronization of two chaotic RCL-shunted Josephson junctions (RCLSJ) based on time-delayed feedback control. The error dynamical system can be dealt with in virtue of non-linear pendulum-like system methods, through which we establish sufficient conditions to guarantee the existence of anticipating synchronizing slave systems. The design of a desired feedback controller can be achieved by solving a group of linear matrix inequalities (LMIs) by utilizing available numerical software. In the presence of parameter uncertainties, we further explore the robust anticipating synchronization, and propose corresponding criteria as well. These results are demonstrated through numerical simulations that under the derived conditions, the slave RCLSJ model could respond in exactly the same way as the master would do in the future, hence it allow us to anticipate the non-linear chaotic dynamics.     

Tertiary Amine — Enhanced Activity of ATRP Catalysts CuBr/TPMA and CuBr/Me6TREN

Tertiary amines were found to remarkably enhance the catalytic activity of ATRP catalysts CuBr/tris[(2‐pyridyl)methyl]amine and CuBr/tris[2‐(dimethylamino)ethylamine]. These two catalysts alone failed to polymerize MA, MMA, and styrene at reduced catalyst concentrations. With tertiary amines such as triethylamine both catalysts could mediate fast polymerizations of the three monomers in a controlled manner at as low as 1 mol‐% catalyst relative to initiator. A mechanism study showed that tertiary amines reduced copper(II) complexes to active copper(I) complexes.

     

两结点简支的弹性基础框架的变形分析

基于初参数法, 研究了均布载荷作用下、两结点简支的弹性基础闭合框架的变形与内力 分布规律. 首先给出了两端弹性支撑的有限长弹性基础梁的挠曲线计算式, 根据结构的边界 条件和对称特性, 不考虑两结点处的位移边界条件, 取出一个局部结构进行了分析; 进而利 用位移和内力的边界条件确定了局部结构的初参数, 并根据结构的对称性得出了整个结构的 内力分布; 最后按照整个结构的位移边界条件, 对以上位移计算结果进行修正, 得出了框架 实际的挠度解析计算式.     

原位聚合甲基丙烯酸盐/低温氢化丁腈橡胶的结构与性能

采用不同阳离子的碱和甲基丙烯酸(MAA),通过混炼和硫化过程的原位聚合,制备了聚甲基丙烯酸盐(SPMAA)改性氢化丁腈橡胶(SPMAA-HNBR).用扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱仪、示差扫描量热仪及浸泡溶胀实验研究了SPMAA阳离子种类(Na+,Mg2+和Al3+)对SPMAA-HNBR性能的影响.结果表明,随着阳离子电荷数的增加,SPMAA逐渐在SPMAA-HNBR内部形成强的离子簇结构,导致其与HNBR间的相容性变差,甚至出现大尺寸的聚集体.这种明显的相分离结构造成聚甲基丙烯酸铝(Al SPMAA)改性氢化丁腈橡胶的拉伸强度和耐油溶胀性能都低于含电荷数较少的聚甲基丙烯酸钠(Na SPMAA)和聚甲基丙烯酸镁(Mg SPMAA)改性氢化丁腈橡胶的性能.各种SPMAA-HNBR的玻璃化转变温度均未发生变化,保持了-30℃的低温弹性.因此,选择生成不同阳离子的SPMAA,可在保持HNBR低温性能的基础上,有效控制SPMAA-HNBR的性能.