Quantum Anomalous Hall Multilayers Grown by Molecular Beam Epitaxy

Quantum anomalous Hall(QAH) effect is a quantum Hall effect that occurs without the need of external magnetic field. A system composed of multiple parallel QAH layers is an effective high Chern number QAH insulator and the key to the applications of the dissipationless chiral edge channels in low energy consumption electronics. Such a QAH multilayer can also be engineered into other exotic topological phases such as a magnetic Weyl semimetal with only one pair of Weyl points. This work reports the first experimental realization of QAH multilayers in the superlattices composed of magnetically doped(Bi,Sb)_2Te_3 topological insulator and Cd Se normal insulator layers grown by molecular beam epitaxy. The obtained multilayer samples show quantized Hall resistance h/N_e~2, where h is Planck's constant, e is the elementary charge and N is the number of the magnetic topological insulator layers, resembling a high Chern number QAH insulator. The QAH multilayers provide an excellent platform to study various topological states of matter.     

高精度单晶硅挠性摆式加速度计组件的工程化实现

针对单晶硅挠性摆式加速度计的高精度工程化应用需求,设计了加速度计组件及温控系统。针对大多数温控系统工作时的瞬时电流较大问题,设计了一种带抽头的加热片,将温控分为粗温控和精温控两个阶段,不同阶段采用不同的加热电阻。测试结果表明,设定目标温度为60℃,当外界环境温度从5℃到55℃变化时,温控系统到温时间小于15 min,控温精度小于±0.1℃,精温控时的最大电流为粗温控时的33.4%。连续15天通电实验表明,该组件的加速度计刻度系数K1稳定性小于10×10~(-6),偏值K0稳定性小于10μg,满足各类高精度、工程化的应用需求。     

剪切型钢筋混凝土柱临界斜裂缝倾角的概率模型

对于剪切型钢筋混凝土(RC)柱,传统的确定性临界斜裂缝倾角模型难以有效考虑其材料参数、几何尺寸和边界约束条件等方面不确定性因素的影响,导致计算精度有限,且离散性较大。鉴于此,本文研究建立了剪切型RC柱临界斜裂缝倾角的概率模型。首先,基于变角桁架模型理论,建立了剪切型RC柱临界裂缝倾角的确定性模型;然后,考虑主观不确定性和客观不确定性因素的影响,结合贝叶斯理论和马尔可夫链蒙特卡洛(MCMC)法,建立了剪切型RC柱临界斜裂缝倾角的概率模型,并推导了均值和方差的解析表达式,从而能够合理描述临界斜裂缝倾角的概率分布特性;最后,利用试验数据对比验证了该模型的有效性,并校准了现有确定性模型的置信水平,进而确定了不同置信水平下剪切型RC柱临界斜裂缝倾角的概率特征值。     

效应代数的表示理论

The aim of this paper is to characterize representable and weak representable effect algebras and establish a representation theory of effect algebras. An effect algebra E is said to be representable if there exists a Hilbert space H and a monomorphism π from E into the Hilbert space effect algebra ε(H) and it is said to be weakly representable if there exists an injective morphism from E into some ε(H). It is proved that an effect algebra E with the nonempty state space S(E) is representable if and only if x, y ∈ E, f(x)+f(y) ≤ 1 implies x⊕y is defined; it is weakly representable if and only if the state space S(E) separates the points of E. Some operational properties of representable effect algebras are established, and some applications of the obtained results are listed.     

硝基苯酰基硫脲衍生物的合成与生物活性研究

酰氨基硫脲类化合物具有很好的生物活性,如消炎、抗菌、抗结核、抗癌、杀菌、杀虫及植物生长调节等[1-8],也是重要的有机合成中间体[9-12].因此,随着新型农药的开发研究,酰氨基硫脲类化合物又成为药物开发的热点之一.     

弹性力学的平衡差分解法

本文从基本的平衡方程出发,导出了含边界条件的弹性力学差分方程;给出了平面问题,梁弯曲问题,薄板弯曲问题的具体形式和算例。这种方法适用各种边界和荷载情况,而且放松了对位移连续性的要求。     

扭转预变形提高Cu71.6Al17Mn11.4形状记忆合金强度和阻尼性能的研究

为了提高铜基形状记忆合金(SMAs)的强度和阻尼性能,并保持较高的恢复应变,本文选择扭转预变形工艺(TPD)对Cu71.6Al17Mn11.4 SMA进行预变形处理,并且研究了几种不同TPD变形量对Cu71.6Al17Mn11.4 SMA的力学性能和相组织结构的影响.结果表明,通过TPD处理后,Cu71.6Al17Mn...     

半群作用Li-Yorke对的存在性

设X为紧度量空间,T为半群,本文研究了动力系统（X,T）上Li-Yorke对的存在性问题,证明了当（X,T）拓扑可迁且包含周期点时,在（X,T）上存在无限scrambled集.另外,列举了一些不包含Li-Yorke对的动力系统.     

半群的混沌作用

引进了半群混沌作用的概念,证明了若半群5在紧致度量空间X上的连续作用满足拓扑可迁和周期点稠两个条件,则此作用满足对初值的敏感依赖性,另外也讨论了半群S在X的逆极限空间上诱导作用的混沌性问题。