Cohen-Macaulay and Gorenstein property of Rees algebras of non-singular equimultiple prime ideals

We give criteria for the Cohen-Macaulay and Gorenstein property of Rees algebras of height 2 non-singular equimultiple prime ideals in terms of explicite representations of the associated graded rings. As consequences, we show that in general, the Cohen-Macaulay resp. Gorenstein property of such Rees algebras does not imply the Cohen-Macaulay resp. Gorenstein property of the base ring and that these properties depend upon the characteristic. Dedicated to the memrory of Professor Lê Van Thiêm Professor Lê Van Thiêm was the first directorof Hanoi Institute of Mathematics     

Stability of strongly continuous representations of abelian semigroups

Part of this work was carried out while the authors were visiting the University of Franche-Comté, Besan?on, and Hokkaido University, Sapporo, respectively     

Characteristics of an add-drop filter composed of a Mach-Zehnder interferometer and double ring resonators

A planar lightwave circuit (PLC) add-drop filter is proposed and analyzed, which consists of a symmetric Mach-Zehnder interferometer (MZI) combined with double microring resonators. A critical coupling condition is derived for a better box-like drop spectrum. Comparisons of its characteristics with other schemes,such as a MZI with a single ring resonator, are presented, and some of the issues about device design and fabrication are also discussed.     

碳纳米管锁模双包层光纤激光器的实验研究

本文采用双包层掺镱光纤作为增益介质,用单壁碳纳米管作为饱和吸收体,获得最高输出功率为336 mW的锁模脉冲激光.用飞秒激光诱导水击穿法直接在单模光纤上制备出D形区,通过在D形光纤上滴涂单壁碳纳米管溶液,成功制备出碳纳米管饱和吸收体,并对其饱和吸收特性进行测试,发现其调制深度为27％.利用该饱和吸收体作为锁模器件,制备出具有环形腔结构的锁模光纤激光器.当抽运功率为4W时,获得了脉宽为93.8 fs,中心波长为1083.8 nm,3 dB谱宽为8.6 nm,重复频率为5.59 MHz,平均功率为336 mW的飞秒脉冲激光输出.     

中国散裂中子源快循环同步加速器主准直器的设计与研究

为满足强流加速器对准直器高散热性能、高抗辐射性能、超高真空、高定位精度、高稳定性和在线实时调整等特殊要求,在CSNS/RCS主准直器设计时针对结构方案和控制方案进行了详细设计和研究,针对关键部件:刮束器、真空盒、驱动装置和远程快速拆卸装置等设计难点进行了阐述,在设计中使用ANSYS完成了刮束器的热分析及支架强度和变形校核,用FLUKA程序对辐射屏蔽进行了分析和设计,确保主准直器设计的可靠性。     

掺Mn对NiFeGa磁性形状记忆材料单晶特性的影响

在单晶Ni₅₄Fe₁₉Ga₂₇中掺入少量Mn，对增强磁交换相互作用，提高居里温度和稳定了B2相并增强晶格的刚度，起到了非常明显的作用.Mn的存在使样品中取向内应力得以保持，提高了变体择优取向的水平，大大提高了单晶的相变应变和磁场增强作用.发现内应力对超弹性性质的影响也很明显. 关键词： 磁性形状记忆合金 NiFeGa 单晶 超弹性     

Rugate光学薄膜通带内反射次峰的抑制

本文探讨了抑制Rugate光学薄膜通带内反射次峰的各种方法。以五次函数匹配和正弦调制相结合的方法获得了在宽光谱范围内能很好抑制反射次峰并能保持其截止带反射率的Rugate膜系。     

用激光感生荧光法测量亚稳态原子寿命

本文用激光感生荧光法(LIF)分析了Gd原子亚稳态能级215cm~(-1),533cm~(-1),999cm~(-1)在原子束中的速度分布。由原子束轴线上两不同点上的亚稳态原子速度分布的变化得到了亚稳态原子的寿命。理论分析和实验结果表明这是一种简单、灵敏并且有效的亚稳态原子寿命测量方法。     

Contract Theory-Based Incentive Mechanism for Full Duplex Cooperative NOMA with SWIPT Communication Networks

Cooperative Non-Orthogonal Multiple Access (NOMA) with Simultaneous Wireless Information and Power Transfer (SWIPT) communication can not only effectively improve the spectrum efficiency and energy efficiency of wireless networks but also extend their coverage. An important design issue is to incentivize a full duplex (FD) relaying center user to participate in the cooperative process and achieve a win–win situation for both the base station (BS) and the center user. Some private information of the center users are hidden from the BS in the network. A contract theory-based incentive mechanism under this asymmetric information scenario is applied to incentivize the center user to join the cooperative communication to maximize the BS’s benefit utility and to guarantee the center user’s expected payoff. In this work, we propose a matching theory-based Gale–Shapley algorithm to obtain the optimal strategy with low computation complexity in the multi-user pairing scenario. Simulation results indicate that the network performance of the proposed FD cooperative NOMA and SWIPT communication is much better than the conventional NOMA communication, and the benefit utility of the BS with the stable match strategy is nearly close to the multi-user pairing scenario with complete channel state information (CSI), while the center users get the satisfied expected payoffs.