Structural study of cubic pyrochlores based on quantum mechanical simulation

In the ideal A₂B₂O₆O′ pyrochlore structure, the x-value of O atom position is a variable parameter. In Bi_1.5ZnNb_1.5−xTa_xO₇ (BZNT) cubic pyrochlores, the x-values alter with the different compositions of Nb/Ta. In this work, a series of initial models for BZNT were established by analyzing X-ray diffraction data. Then three structure modifying methods, including Rietveld refinement, Rietveld refinement with energy and geometry optimization based on quantum mechanics, were employed to obtain the precise models using Materials Studio. Moreover, the reflectivities of BZNT were computed by quantum mechanical simulation based on the refined models. Comparing the simulation results from different modifying models with the experimental results, it is found that Rietveld refinement with energy optimization is the most accurate method for BZNT pyrochlores. According to the simulation results, the different reflectivities correspond well with various x-values of O atom positions in BZNT pyrochlores.     

B 炸药中绝热剪切带形成机理的细观研究

通过对快速加载后Ｃｏｍｐ．药柱剖面的扫描电镜和光学显微镜观察分析，对Ｃｏｍｐ．Ｂ炸药在快速加载下剪切带形成机理的微观机制有了初步的认识。文中采用形变试样的剖面观察分析方法，针对固体药柱这种比较软的材料，如何进行磨样、抛光、浸蚀，作了一些尝试和探索，总结出一套有效的实施办法。对不同加载速率条件下受压缩的药柱中细观组织进行了观察、分析、比较，首次给出国产Ｃｏｍｐ．Ｂ炸药装药的原始细观组织形貌，以及快速加载后药柱中细观组织形貌。经过分析，得到冲击载荷下炸药装药中绝热剪切带形成、发展的定性认识，为分析Ｃｏｍｐ．Ｂ炸药装药受冲击载荷时热点形成机理提供了一些有益的实验依据。     

高水材料结石体抗压强度环境效应试验研究

借助MTS力学试验系统、SEM电子扫描电镜和X射线衍射等分析设备,对在不同环境下高水速凝结石体的主要物理力学指标、结构特征及内部物质组成进行测试,研究高水结石体强度特征的环境效应。结果表明：高水结石体在不同PH值水环境中强度差异并非由其物质成分变化引起的,PH值主要通过影响结石体的微观结构而使其体现出不同的强度特征;空气环境中,结石体抗压强度值、变形常数及泊松比均大幅减小,力学性质差;水环境中,PH值=5.5时试样的抗压强度值最大,变形常数和泊松比在不同PH值环境中均减小,泊松比呈现随环境酸度或碱度的增大而迅速减小的趋势;不同环境中结石体应力-应变关系曲线相似,应力增长较快且体现蠕变特性。     

A digital twin in transportation: Real-time synergy of traffic data streams and simulation for virtualizing motorway dynamics

The introduction of digital twins is expected to fundamentally change the technology in transportation systems, as they appear to be a compelling concept for monitoring the entire life cycle of the transport system. The advent of widespread information technology, particularly the availability of real-time traffic data, provides the foundation for supplementing predominated (offline) microscopic simulation approaches with actual data to create a detailed real-time digital representation of the physical traffic. However, the use of actual traffic data in real-time motorway analysis has not yet been explored. The reason is that there are no supporting models and the applicability of real-time data in the context of microscopic simulations has yet to be recognized. Thus, this article focuses on microscopic motorway simulation with real-time data integration during system run-time. As a result, we propose a novel paradigm in motorway traffic modeling and demonstrate it using the continuously synchronized digital twin model of the Geneva motorway (DT-GM). We analyze the application of the microscopic simulator SUMO in modeling and simulating on-the-fly synchronized digital replicas of real traffic by leveraging fine-grained actual traffic data streams from motorway traffic counters as input to DT-GM. Thus, the detailed methodological process of developing DT-GM is presented, highlighting the calibration features of SUMO that enable (dynamic) continuous calibration of running simulation scenarios. By doing so, the actual traffic data are directly fused into the running DT-GM every minute so that DT-GM is continuously calibrated as the physical equivalent changes. Accordingly, DT-GM raises a technology dimension in motorway traffic simulation to the next level by enabling simulation-based control optimization during system run-time that was previously unattainable. It, thus, forms the foundation for further evolution of real-time predictive analytics as support for safety–critical decisions in traffic management. Simulation results provide a solid basis for the future real-time analysis of an extended Swiss motorway network.     

Correlation between the plating regime of lead film deposition and electrode response after accumulation of organic compound. Microscopic study

The properties of the lead film electrode designed for adsorptive stripping voltammetric measurements of organic compounds were examined by electrochemical and microscopic techniques. The effect of Pb(II) concentration, the influence of deposition potential and time of the lead film formation on the determination of bleomycin at an in situ lead-coated glassy carbon electrode have been studied. Atomic force microscopy (AFM) was used to characterize the Pb crystallite growth on the glassy carbon surface. The morphology of the deposits was evaluated and its influence on the bleomycin responses was discussed.     

相变诱发塑性钢的研究现状与发展

在现代汽车制造业对汽车轻量化提出要求的趋势下,TRIP钢因其同时具有高强度和高的断后伸长率,以及其优良的高速力学性能而受到青睐。本文简要介绍了相变诱发塑性钢(TRIP钢)的发展现状与研究进展;详细介绍了TRIP钢中各种合金元素的作用,显微组织与性能的关系以及热处理工艺;最后对TRIP钢的发展趋势做了简要阐述。     

Effective stiffness and microscopic deformation of an orthotropic plate containing arbitrary holes

Many engineering materials and structures, such as cellular structures, sandwich core structures and laminated plates with holes, can be modeled by an inclusion problem with anisotropic matrix. The paper studies the effective properties and the microscopic deformation of anisotropic plates with periodic holes by using direct and mathematical homogenization. The effective stiffnesses are calculated by different homogenization methods and the microscopic deformation of a RVE is modeled by the finite element method for the plate with arbitrarily shaped holes. All of the effective stiffness coefficients, especially stretching-shear coupling coefficients are evaluated.     

Extraction of karyocytes and their components from microscopic bone marrow images based on regional color features

Extracting karyocytes and their components from microscopic bone marrow images is prerequisite for computer-aided early diagnosis of hemopathy. Most existing methods assume all pixels belonging to a karyon region or a cytoplasm region have similar colors. Practically, the color of neither a karyon nor a cytoplasm in a microscopic image is homogeneous in the pixel level. Therefore, the regional color features of a region are emphasized in this paper. Based on this observation, we propose a novel method to karyocyte extraction that first identifies a karyon by 4-connected block growing from a karyon feature block, then identifies feature blocks of its cytoplasm based on the extracted karyon, and finally extracts all cytoplasm regions by growing the cytoplasm feature blocks. Combining the karyon region and the corresponding cytoplasm regions can attain a complete karyocyte. Experimental results show that the proposed method is effective and robust.     

Spatiotemporal mapping of microscopic strains and defects to reveal Li-dendrite-induced failure in all-solid-state batteries

Solid-state electrolytes (SSEs) are key to the success and reliability of all-solid-state lithium batteries, potentially enabling improvements in terms of safety and energy density over state-of-the-art lithium-ion batteries. However, there are several critical challenges to their implementation, including the interfacial instability stemming from the dynamic interaction of as-formed dendritic lithium during cycling. For this work, we emphasize the importance of studying the spatial distribution and temporal evolution of strains and defects in crystalline solid-state electrolytes at the micro-scale, and how this affects dendrite growth. A proof-of-principle study is demonstrated using the synchrotron radiation based micro Laue X-ray diffraction method, and a custom-developed in-situ cycling device. Defects and residual strains are mapped, and the evolution of intragranular misorientation is observed. The feasibility of using this technique is discussed, and recommendations for micro-strain engineering to address the Li/SSEs interfacial issues are given. Also, work directions are pointed out with the consideration of combining multi-techniques for “poly-therapy”.