真空开关电器中接触触点热过程的仿真研究

金属蒸气是真空开关电弧存在的根源, 基于流体动力学理论, 建立真空开关开断初期分离最终电接触触点由固体、金属液桥到金属蒸气相变过程的完整模型。考虑了金属触点的熔化变形边界, 同时关注金属液桥断裂后金属蒸气的扩散过程, 计算结果表明电触点最高温度点出现在接触触点的中心, 也正是金属桥断裂形成的初始位置。金属液桥相变过程中伴随金属蒸气的蒸发, 并在真空环境中迅速扩散, 在阴极斑点形成之前, 金属蒸气密度高达1.092×10²⁵ m^-3, 并沿着扩散半径迅速降低。计算结果表明, 随着电极加载电流的增大, 金属液桥完全断裂时间大大缩短。     

Circadian Rhythm Disorders Aggravate Periodontitis by Modulating BMAL1

Circadian rhythms regulate the body’s homeostasis through the temporal control of tissue-specific circadian rhythm control genes. Circadian rhythm disorders (CRD) affect the expression levels of circadian rhythms-associated genes in brain and muscle aryl hydrocarbon receptor nuclear translocator-like-1(BMAL1), which is thought to contribute to metabolic disorders and an altered immune system. However, the relationship between CRD and the development of periodontitis was poorly reported. Therefore, this study aimed to investigate the role played by BMAL1 in periodontitis. We used a modified multi-platform approach (MMPM) to induce circadian rhythm disturbances in rats to investigate the role of BMAL1 in periodontitis. Our results showed significant downregulation of BMAL1 in the CRD with periodontitis group, significant resorption of alveolar bone, increased osteoclast differentiation, and upregulation of the inflammatory signaling molecule NF-κB. In addition, apoptosis and oxidative stress levels were increased in periodontal tissues. Collectively, our study suggests that BMAL1 is a key regulator in periodontitis exacerbated by CRD and that CRD may lead to the downregulation of BMAL1, thereby exacerbating oxidative stress and apoptosis in periodontal tissues. Our study found that BMAL1 may be associated with the progression of periodontitis and provides a new perspective on the treatment of periodontitis.     

光纤集成化高分辨率无标记差分显微成像系统

得益于荧光标记技术,远场超分辨显微成像技术的不断发展为人们打开了一道微观世界的大门。远场超分辨光学显微镜也成为现代医学、生命科学等领域研究发展的重要工具和设备。但是相比之下,远场无标记显微成像技术发展却相对缓慢。为此,本文提出了一种采用光纤器件的集成化差分显微成像方法。该方法通过特制的光纤模式选择耦合器(MSC)实现了差分成像系统中空心光斑的生成,并解决了空心光斑和实心光斑严格对准困难的问题。搭建了一套结构简单紧凑,高度集成化的无标记显微成像系统。实验中,采用直径为150 nm的金颗粒和最小间距约50 nm的无标记聚合物线对结构对系统进行成像测试,分辨率相较传统扫描共聚焦显微镜大幅提升。

     

太赫兹技术在医学科学中的应用及研究进展

近年来太赫兹光(0.1 THz~10 THz)因其良好的探测能力和非电离特性受到研究者们的关注。根据不同的检测方式和信号处理方法,可分为太赫兹成像技术和太赫兹光谱技术两大类。太赫兹技术在医学科学中发展迅速,其中生物大分子检测和组织成像令人印象深刻。水含量和结构差异是太赫兹成像技术的理论基础,据此可对生物组织进行检测识别。不同的生物组织具有不同的太赫兹特征谱,太赫兹光谱技术通过检测吸收系数、折射系数和反射系数来识别不同的生物分子、细胞或组织。实时、无标记的检测方式有望在临床实践中发挥重要作用,但仍需克服生物安全性不明等困难。综述介绍了太赫兹技术在医学科学中的应用及研究进展,同时探讨了太赫兹技术目前需要克服的难题和潜在的生物安全性问题。

     

光纤偏振器件与组件的分布式串音测量研究进展

偏振串音是指光纤偏振器件与组件中两个正交偏振传输模式之间在微扰点发生的能量相互耦合的现象,而沿传输方向串音的连续分布既能够直接反映其光学偏振性能,如起偏、椭偏、消偏等特性,也能间接反映其制备工艺和外部环境状态,如连接与固定处的应力和应变、温度状态等。因此,偏振串音是光纤偏振器件与组件的固有性能和环境影响的综合体现,有望发展成为在线测试、诊断评价光纤偏振器件与组件性能的通用特征参量。基于白光干涉原理的光学相干域偏振测量(OCDP)技术是实现分布式偏振串音检测的最优方法,它利用扫描式白光干涉仪实现不同偏振模式间的干涉,对分布式串音发生的空间位置及幅值强度进行精确测量,具有超高灵敏度、超大动态范围、超长测量长度等优点。本文以光纤偏振器件与组件——保偏光纤环和多功能集成光学调制器作为分布式偏振串音精确测量与应用的范例,介绍了基于OCDP技术的分布式串音测试原理,回顾了测量误差的来源及相应的抑制方法,如由测试光路的参数非理想引入的静态误差以及由测试环境变化引入的动态误差,展示了不同环境温度下光纤偏振器件与组件的精确测试结果。最后,结合光纤偏振器件与组件复杂多变的工作环境,对分布式串音测量方法的发展进行了展望。

     

Electrolyte/Structure?Dependent Cocktail Mediation Enabling High?Rate/Low?Plateau Metal Sulfide Anodes for Sodium Storage

As promising anodes for sodium-ion batteries, metal sulfides ubiquitously suffer from low-rate and high-plateau issues, greatly hindering their application in f...     

天车调度在优化钢厂物流管制中的重要作用

运用物流学中装卸搬运的知识,归纳了现代制造流程中运输环节的功能和作用,分析了炼钢厂物流系统中天车作业的特点,并对钢厂时间因素和生产工艺进行了研究与分析,从中可知天车调度在优化钢厂物流管制中的重要作用。     

地下矿井巷工程CAD及造型系统3DMS的研究与开发

在AutoCAD for Windows环境下开发地下矿井巷工程计算机辅助设计及实体造型系统3DMS.根据采矿设计规范开发辅助设计及绘图工具;建立井巷工程数据库,从设计图中识别井巷工程并录入井巷工程的几何参数及其属性;以井巷工程数据库为基础,利用AME(AutoCADModelling Extention)技术开发可视化井巷工程实体造型系统.3DMS系统的推广应用,能够大幅度提高设计效率和质量.     

Scheduling Dual-Arm Multi-Cluster Tools With Regulation of Post-Processing Time

As wafer circuit width shrinks down to less than ten nanometers in recent years, stringent quality control in the wafer manufacturing process is increasingly important. Thanks to the coupling of neighboring cluster tools and coordination of multiple robots in a multi-cluster tool, wafer production scheduling becomes rather complicated. After a wafer is processed, due to high-temperature chemical reactions in a chamber, the robot should be controlled to take it out of the processing chamber at the right time. In order to ensure the uniformity of integrated circuits on wafers, it is highly desirable to make the differences in wafer post-processing time among the individual tools in a multi-cluster tool as small as possible. To achieve this goal, for the first time, this work aims to find an optimal schedule for a dual-arm multi-cluster tool to regulate the wafer post-processing time. To do so, we propose polynomial-time algorithms to find an optimal schedule, which can achieve the highest throughput, and minimize the total post-processing time of the processing steps. We propose a linear program model and another algorithm to balance the differences in the post-processing time between any pair of adjacent cluster tools. Two industrial examples are given to illustrate the application and effectiveness of the proposed method.

     

小方坯连铸机铸坯质量研究

邯郸钢铁厂R5.25米的一机四流弧形小方坯连铸机。本文结合现行工艺操作,调查研究了小方坯铸坯的表面质量,内部质量和产品的机械性能。为改善铸坯质量提供了依据。