制备软X光多层膜的转速控厚法

本文提出了一种新的监控软X光多层膜膜厚的方法——转速控厚法,利用这种方法镀制的设计周期厚度分别为8.4和10nm,周期数达50对和30对的W/C多层膜,经小角X光衍射测试,结果表明周期厚度随机误差在0.1nm左右。     

ZnSe纳米材料及界面的制备与表征

利用热蒸发法对ZnSe纳米材料的相控合成进行了研究,制备了多种具有稳定闪锌矿和亚稳纤锌矿结构的ZnSe纳米材料,如ZnSe纳米线、纳米圈、纳米轮及三晶纳米带。同时,在相控合成基础上,通过改变管式炉内反应压强获得了几种同质与异质界面。利用多种透射电子显微学手段对合成的ZnSe纳米材料及相关同质与异质界面进行了深入表征,并对ZnSe纳米材料的生长机理进行了探讨。     

杠杆耦合式微机械陀螺仪特性分析

基于机械杠杆的位移放大效应,提出了一种具有微杠杆结构的电容检测式微机械陀螺结构,所设计的杠杆放大机构设置在陀螺的检测模态中,通过杠杆将科氏质量块的检测位移放大传递到检测框上,以提升检测位移。建立杠杆结构陀螺的二阶振动微分方程,分析了杠杆结构对微机械陀螺结构静刚度和固有频率的影响,探讨了在不同结构条件下杠杆结构对检测位移的放大效果。通过仿真验证了理论的准确性与可行性,结果表明,在陀螺谐振情况下,可有效增大检测框位移60%以上,提升了检测位移,进而提升检测灵敏度。     

丙酮/水混合体系合成聚苯胺的聚合过程研究

对丙酮/水体系中合成聚苯胺(PAn)的反应进行跟踪,通过聚合过程的开路电压、聚合温度、特性粘度和中间体的分子结构对聚合过程进行研究。结果表明,丙酮/水体系对控制产物的粒度和分子量都有利;当丙酮/水的体积比为0.2左右时,所得产物的各项性能较好。与水体系相比,在丙酮/水混合体系中聚合过程维持高电位的时间延长,聚合链增长时间和自加速反应时间也有延长。苯胺聚合是以头-尾连接形式进行,且中间产物由高氧化态逐渐转变成中间氧化态。     

基于层次分析法的风洞试验装备全寿命健康因素量化评价方法研究

针对风洞试验装备健康管理面临的实际问题,基于层次分析法(AHP)确定装备全寿命过程中影响装备健康的因素体系,并计算各类因素所占的权重,建立了量化评价模型和反馈修正方法,并给出了该方法在风洞试验装备健康管理工作中的实际应用流程。     

全球减灾与灾害物理学(三)——灾害声学及其噪声控制技术

声环境是环绕人们的并对其生存产生很大影响的重要条件,但以往人类只注意发展声环境的正向方面,而对于由此产生的隐伏的声危害却关注不够,从而致使声环境会给人类带来灾难性的环境压力,危及人类健康．本文重点介绍突出的灾害噪声问题及其控制技术．     

玻碳电极表面复合配位银电结晶机理研究

以具有实际应用价值的复合配位体系无氰镀银电解液为研究对象, 运用循环伏安和电位阶跃等实验方法, 结合 Scharifker-Hill 经典理论模型分析, 成功获得了Ag在玻碳电极（GCE）表面电沉积的成核机理及成核动力学参数, 并分析了温度对成核方式及成核动力学参数的影响. 结果表明, 该体系下Ag在GCE表面的电沉积是由扩散控制的不可逆过程, 遵循三维瞬时成核生长机理. 随着阶跃电位从-750 mV 负移至-825 mV, 峰值还原电流Im逐渐增大, 达到峰值还原电流所需时间tm逐渐缩短; 扩散系数D变化不大, 基本稳定在（7.61±0.34）×10^-5 cm²·s^-1; 成核密度数N₀则从3.26 ×10⁵ cm^-2提高至10.2×10⁵ cm^-2. 银沉积初期的形貌观察, 验证了其三维瞬时成核生长机理. 提高温度可以显著改善电解液中具备活性的银配位离子的扩散能力, 缩短成核时间, 提升成核密度数N0.     

The robustness of sparse network under limited attack capacity

The paper studies the robustness of the network in terms of the network structure. We define a strongly dominated relation between nodes and then we use the relation to merge the network. Based on that, we design a dominated clustering algorithm aiming at finding the critical nodes in the network. Furthermore, this merging process is lossless which means the original structure of the network is kept. In order to realize the visulization of the network, we also apply the lossy consolidation to the network based on detection of the community structures. Simulation results show that compared with six existed centrality algorithms, our algorithm performs better when the attack capacity is limited. The simulations also illustrate our algorithm does better in assortative scale-free networks.     

块石形状对土石混合体力学行为影响的颗粒流模拟

考虑块石形状为球体、正方体和长方体三种情况,通过正方体与球体相比较来探究块石棱角度不同对土石混合体力学特性的影响,通过长方体与正方体相比较来探究块石球度不同对土石混合体力学特性的影响。首先,提出特定形状块石三维离散元精细建模的方法;接着建立含石量为30%和80%的块石形状分别为球体、正方体和长方体的土石混合体三维颗粒流数值模型;然后,对土石混合体大三轴试验进行颗粒流模拟,获得了不同含石量及不同块石形状的土石混合体试样的宏观力学特征;最后,详细分析了块石形状对土石混合体力学行为影响的细观机理。结果表明,块石形状会影响土石混合体的力学行为,其影响的程度与含石量密切相关;配位数、块石颗粒平均旋转量和摩擦功的演化规律能够很好地从细观水平上反映块石形状的作用机理。     

Three-dimensional size and orientation of the precipitates in AZ91 magnesium alloys measured by TEM techniques

Knowledge of the microscopic structure, including three-dimensional (3-D) size and orientation of the precipitates, is essential to fully understand the mechanical properties of the magnesium alloys and designing the alloys with better performance. Analytical TEM with high spatial resolution offers the simultaneous measurements of 3-D size, structure, orientation, composition of the precipitates from one typical sample along an established crystallographic axis. Besides popular Burgers orientation relationship (OR), other ORs such as Pitsch--Schrader OR, Crawley OR, Potter OR and a new OR with the form of [0001]_α 1.0° from [311]_γ and (11\bar 20)_α 2.0° from (03\bar 3)_γ between the magnesium matrix and the precipitate γ -Mg₁₇Al₁₂ are identified by TEM imaging and diffraction techniques. As a case study, the thicknesses of the individual precipitates with Burgers OR are further measured to be 100--200~nm through both electron energy-loss spectroscopy and x-ray energy dispersive spectroscopy combining differential x-ray absorption and extrapolation, which are in agreement with the overall 3-D size statistic distribution results obtained through analysing various samples along various directions. Furthermore, the fabricated wedge-shape structure provides a platform on which to study the dependence of the interfacial strain on the variation of the thickness.