开采引起地表沉陷规律的有限元分析

地表移动规律是采矿领域的重要研究内容。开采必将对覆岩、地表以及地表附属物造成影响,地表移动规律是反映影响程度的尺度。本文通过有限元分析计算得出哈拉钩矿开采后地表下状况,为研究该矿区地表移动规律提供定量的依据。     

Air oxidation behavior of nitrogen ion implanted zircaloy-4 at 500 °C

Journal of Materials Science -     

Influences of ZrO<Subscript>2</Subscript> nanoparticles on the microstructure and mechanical behavior of Ce-TZP/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> nanocomposites

Influences of ZrO₂ nanoparticles on the mechanical properties and microstructure of hot-pressing Ce-TZP/Al₂O₃ ceramics were investigated. Meanwhile, t-ZrO₂ to m-ZrO₂ transformation toughening mechanism was investigated by X-ray diffractometry (XRD) method, and deflection of samples under applied stress were recorded too. The results show that when the percentage of ZrO₂ was 20%, the mechanical properties and microstructures of materials are optimum. Moreover, TEM observation show dislocation structures formation both in the Al₂O₃ and on the grain boundary. Because the dislocation agglomeration and fixation by ZrO₂ nanoparticles could deflect cracking or stop cracking development, a strengthening and toughening effect could be achieved.     

Bridgman growth of bismuth tellurite crystals

The photorefractive crystal, Bi₂TeO₅, was grown by the modified Bridgman method for the first time. High purity Bi₂O₃ and TeO₂ were used as starting materials and were mixed thoroughly with molar ratio of Bi₂O₃/TeO₂ = 1 ∶ 1. Platinum crucible was fabricated with a seed well of 10 mm in diameter and several folds were pressed so that the spontaneous nuclei could be eliminated through competition. The crucible was sealed during the growth so that the evaporation of TeO₂ was controlled effectively. By optimizing growth parameters, transparent and crack-free Bi₂TeO₅ crystal up to 25 mm in diameter and 40 mm in length was grown successfully.     

One-step and rapid synthesis of high quality alloyed quantum dots (CdSe-CdS) in aqueous phase by microwave irradiation with controllable temperature

In this paper, we presented a seed-mediated approach for rapid synthesis of high quality alloyed quantum dots (CdSe-CdS) in aqueous phase by microwave irradiation with controllable temperature in 1 h. In the synthesis, CdSe seeds were first formed by the reaction of NaHSe and Cd²⁺, and then alloyed quantum dots (CdSe-CdS) were rapidly produced by releasing of sulfide ions from 3-mercaptopropionic acid as sulfide source with microwave irradiation. The alloyed quantum dots synthesized had good optical properties, the quantum yield was up to 25%, and the full width at half maximum of the emission spectrum peak was about 28 nm. The as-prepared alloyed CdSe-CdS QDs were characterized by XRD, XPS and ICP-AES in order to explore the structure and component of the alloyed nanocrystals and the reaction mechanism. We speculate that the alloyed CdSe-CdS quantum dots may exist a gradient internal structure according to our preliminary results.     

JMASE与HLA仿真系统的互连研究

JMASE是一个建模与仿真的支撑环境，主要用于构建分析和测试领域所需要的工程级和交战级数字系统模型和仿真系统，它采用的是基于事件的仿真调度机制，通过端口消息进行通信。JMASE提供了灵活易用而且功能强大的开发工具、配置工具、执行工具和分析工具支持建模与仿真的全过程，还提供一系列的公共服务方便模型的开发，极大地促进了模型与仿真的重用以及互操作。该文在介绍JMASE基本概念、特点和功能的基础上，基于JMASE的事件调度机制和数据日志服务以及HLA的接口规范开发了一个JMASE—HLA框架，实现了JMASE仿真系统与HLA仿真系统的互连。     

企业网中虚拟局域网的实现研究

通过对虚拟局域网的划分方法及一个典型的企业网的实现,从理论、实现两方面对其技术及应用做探讨.     

磁调制器的建模与仿真研究

基于MATLAB软件中的SIMULINK仿真环境建立了磁调制器的仿真模型,它可以精确模拟坡莫合金磁化曲线的饱和段,有效克服传统作图法的不足,能够快速分析包括激励线圈、直流偏磁线圈、检测线圈等的内阻在内的各种参数对调制性能的影响,有利于了解磁调制器工作机理,对于快速设计具有合理特性的磁调制器有指导意义。     

压电智能夹层及其特性分析

压电智能夹层可以有效地解决压电自诊断系统中直接使用压电片引起的弊端.通过适当改进当前的柔性印刷线路工艺制作出的压电智能夹层,不仅具有柔性印刷线路的特点,而且,应用在结构健康监测系统中还有其他一些独特的优越性能.并利用压电智能夹层进行了初步的拉伸载荷识别,同压电片相比,识别效果更明显.     

一种新型超声波油料密度检测装置的设计

现行的检测手段已经不能满足现代油料计量的发展要求,研究一种精度高的在线检测装置十分必要。利用超声波纵波的特性,提出一种利用超声波在油料中传播的时间差和相位差两项指标综合判定油料密度的方法,并设计了检测装置。通过试验证明:该装置具有稳定性好、灵敏度高、测量范围广、自动化程度高、响应速度快以及抗暴性能好等特点,完全可以满足油料密度在线检测的需要。