相同子结构串的本征对问题及展开解法

本文讲述了串连式子结构的分析计算方法,它相当于结构分析中按横截面展开的方法。文中讲述了移位不变法以及初参数与传递矩阵法两个方面,并指明了两种方法的联合运用及相互关系,截面上本征值问题的计算以及按本征向量展开等问题。     

Eigenproblem of substructure chain and the expansion solution

In this paper, a new method for dealing with substructure chain is presented. Here, a substructure chain means a structure consisting of a number of identical substructures connected in series. This method is parallel to the expansion method in the structural analysis according to the transverse section. The method of shift invariance and that of initial parameter and transfer matrix, their mutual-relation and combined use, as well as the analysis of the eigenproblem on the transverse section, and the expansion method based on the eigenvectors are described in this paper. Project supported by National Natural Science Foundation of China.     

基于首超破坏机制的大跨斜拉桥抖振动力可靠性分析

分别采用泊松分布和马尔可夫过程，给出了在一次强风作用下以及在设计基准期内桥梁结构某一特定截面或节点的抖振动力可靠性分析方法。然后，考虑斜拉桥的结构特点及其承受风荷栽的具体情况，确定了以斜拉桥的主梁系统为研究对象的结构体系抖振动力可靠性分析模型。在此基础上，采用串联失效模式，建立了斜拉桥主梁系统抖振动力可靠性分析过程。本文采用有限元法分析结构的空气静力响应。为了快速、准确地计算结构的抖振响应，考虑气弹力与抖振力的联合作用以及多模态耦合效应，采用有限元法和虚拟激励法相结合分析结构的抖振响应。最后，以某大跨斜拉桥为工程背景，对其主梁系统进行了基于刚度要求的抖振动力可靠性分析。     

基于USB的箭载数字量变换器测试仪设计

为配合箭上某型号数字量变换器进行全面的性能测试,通过对数字量变换器性能指标以及各状态信号的分析,提出了基于USB接口的高速数字量变换器测试仪的设计方案;详细说明了系统各功能模块的实现方法,并对系统进行了实际的分析和测试;与以往测试仪器性能相比,该设计从硬件、软件及其工作模式方面都做了一些优化,明显提高了测试的精度;系统整体采用模块化设计方法,完成幅值8-10 V的计算机字信号以及幅值28 V的指令信号的传输,具有很强的通用性和可扩展性;在实际应用中,该测试仪设计可行,能全面检测数字量变换器的性能。     

Highly-Efficient Ion Gating through Self-Assembled Two-Dimensional Photothermal Metal-Organic Framework Membrane

Biological ion channels regulate the ion flow across cell membrane via opening or closing of the pores in response to various external stimuli. Replicating the function of high ion gating effects with artificial porous materials has been challenging. Herein, we report that the self-assembled two-dimensional metal-organic framework (MOF) membrane can serve as an excellent nanofluidic platform for smart regulation of ion transport. The MOF membrane with good photothermal performance exhibits extremely high ion gating ratio (up to 10⁴), which is among the highest values in MOF membrane nanochannels for light-controlled ion gating reported so far. By repeatedly turning on and off the light, the nanofluidic device shows outstanding stability and reversibility that can be applied in the remote light-switching system. This work may spark promising applications of MOF membrane with variety of stimuli responsive properties in ion sieving, biosensing, and energy conversion.     

香港青马桥抗震分析

对香港青马桥的地震反应分析表明，地震地面运动的空间变化效应（特别是行波效应）对大跨度结构的响应有着相当大的影响。本文也表明随机振动方法在处理多点激励地震问题时相对于当前广泛使用的反应谱方法具有明显的优越性。     

转子系统的平稳／非平稳随机地震响应分析

应用虚拟激励法结合精细时程积分计算了转子系统受平稳／非平稳随机地震激励的动力响应。采用虚拟激励分析将平稳随机激励转化为稳态简谐激励，将非平稳随机激励转化为瞬态确定性激励，即使对于非对称的油膜刚度阵和阻尼阵，算法仍然简单高效，并得到精确的结果。     

Determination of the half-life of 184gRe and the isomeric ratio of 184m,gRe induced by D-T neutrons

The isomeric ratio of ^{184m, g}Re and the half-life of ^184gRe were measured in the ¹⁸⁵Re (n, 2n) ¹⁸⁴Re reaction at 14.8 MeV, and the uncertainty was discussed in detail. The measurements were performed using the activation method implemented for a rhenium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics (CAEP). Isomeric state and ground state nuclei of ¹⁸⁴Re were identified by their γ-ray spectra. To eliminate the effect of the γ-ray emitted from the isomer on the counting of the ground state characteristic peaks, the isomeric ratio of ^{184m, g}Re was calculated to be 0.29 ± 0.11 according to the neutron activation cross-section formula. This result is consistent with previous data within the uncertainty and can be used to determine parameters that characterize the dependence of the level density on the excitation energy and angular momentum. Through exponential function fitting and a detailed discussion of the uncertainty evaluation, the half-life of ^184gRe was determined as 35.43 ± 0.16 d, which is consistent with the currently recommended value; however, the uncertainty assessment of the latter was barely documented. In addition, this study indicates that the half-life of the ground state can be obtained by eliminating the contamination of γ-rays emitted from the isomer, which provides the possibility of determining the half-lives of nuclides containing isomers.