一种外磁场自抑制霍尔电流传感器

本文分析了几种外磁场自抑制技术,设计了一种外磁场自抑制霍尔电流传感器。研制的传感器在80Gs磁场下,零点输出变化在0.6%FS以内,传感器抗磁场干扰能力大大提高。     

建筑钢结构焊接残余应力磁测技术研究

本文从铁磁材料内部磁畴结构角度出发,介绍了铁磁材料的应力致磁各向异性特性。磁弹性法测残余应力即通过对材料导磁率变化的检测反映材料表面的应力水平。将磁弹性应力检测技术应用到工程实际中,标定了Q235钢的磁测灵敏系数,利用sc21型残余应力磁测仪对建筑钢结构的焊接残余应力进行了测量。     

Ca掺杂对SmCoAsO磁性的影响

为了探究SmCoAsO体系中Sm在其磁性中的作用,用Ca在Sm位进行掺杂。采用固相反应法制备Sm1-xCaxCoAsO(x=0,0.05,0.1,0.2),通过X射线衍射仪、超导量子干涉仪等对其结构和磁性进行表征。结果表明,制得的Sm1-xCaxCoAsO单相性较好,具有四方ZrCuSiAs型晶体结构,且Ca掺杂对晶格参数的影响很小。Sm1-xCaxCoAsO在低温下发生了反铁磁、铁磁及亚铁磁多重磁转变,而且在反铁磁转变温度以下,观察到了磁场导致的变磁性转变,且变磁场随温度的升高而降低。Ca在Sm位掺杂抑制了SmCoAsO的亚铁磁转变,当掺杂量为0.2时,亚铁磁转变温度降低了23K。因此,在SmCoAsO中,Co的磁矩决定铁磁和反铁磁性,而Sm经由在c方向上的Sm-O层与Co-As层之间的相互作用决定亚铁磁性。     

一种多通道光吸收增强的石墨烯结构

为改善石墨烯的光吸收性能并实现多通道吸收,提出一种含间隔层的光子晶体异质结构。利用4×4传输矩阵法研究了设计波长、外磁场、费米能量和光子晶体周期数等参数对该结构吸收特性的影响。结果表明:由于石墨烯的磁光效应,在外磁场的作用下该结构的吸收特性表现出一定的磁圆二色性,且其多通道吸收特性可通过外磁场和费米能量来实现调节;吸收通道数和位置可通过设计波长、间隔层厚度和光子晶体的周期数等参数来调节。研究结果可为基于石墨烯的多通道光吸收器和磁圆二色性传感器等器件的设计提供参考。     

钢箱梁桥挑檐制作工艺方法

武汉市二环线钢箱梁桥挑檐因其多处位置设计采用薄板焊接,焊接变形难以控制,现场安装线形不易保证.根据钢箱梁桥挑檐制作过程中的方法,通过提炼总结,制定合理制作顺序及控制焊接变形工艺,为同类钢箱梁桥结构制作提供经验.     

一种抗强工频磁场干扰的泄漏电流传感器设计

针对特高压变电站避雷器泄漏电流数据采集不准确的问题,在实验室内搭建工频磁场仿真环境,对不同结构的电流传感器进行工频磁场采集精度试验,选取一种抗干扰能力最好的线圈结构进行设计.设计一种双线圈泄漏电流传感器,经实验室和现场测试,结果表明该传感器在强工频磁场干扰下采集误差≤±2％,满足泄漏电流采集技术规范要求.     

铁磁材料磁化涡旋在应变作用下的响应

磁化涡旋是微米/亚微米铁磁材料中一种常见的磁畴结构,由于它可以被用于高密度的磁性存储设备中,近年来受到了人们的广泛关注。本文基于随时间变化的Ginzburg-Landau方程,采用实空间下的相场模型研究了铁磁材料中磁化涡旋的力磁耦合行为,探讨了铁磁纳米圆柱体中自发磁化涡旋形态以及该结构在沿圆柱体轴向应变作用下的响应行为。结果表明,沿圆柱体轴向的应变对面内磁化分量的幅值和分布影响十分微弱,但对垂直于圆柱体表面磁化分量的影响却十分明显,具体表现为平面外磁化分量的幅值将随着拉应变的增大而增大,又会伴随压应变的增大而减小。随着平面外磁化分量的增加,则更容易探测到该磁化涡旋的极性情况,从而有利于实验观察和实际应用。     

基于单片机的管道漏磁检测系统硬件设计

本文主要介绍了基于51单片机的磁场检测系统硬件设计、工作原理及主要功能。该实验以8051单片机为核心,采用线性霍尔元件UGN3503UA作为传感器来感应线圈磁场的变化,并将磁场的变化转化为电压的变化,硬件系统主要由单片机、磁传感器、A/D模块、显示器等组成,该系统的研究主要是为了能更好的应用于磁场检测等方面,比如管道漏磁检测、缺陷漏磁场的检测等。     

建筑索结构索力测量新方法与工程应用

索作为建筑索结构中的重要构件,索的预张力大小是索结构设计中的重要参数,也是索结构施工过程中进行控制的重要环节。开发新型的索力传感器是索结构施工监测和控制中面临的新课题。基于铁磁材料的磁弹性能阐述磁弹法测量索力的基本原理,开发了一种新型的磁通量传感器,并将其应用在双曲面索网模型张拉试验中进行索力监测控制。试验结果表明,该方法可以非常方便快捷、准确地测定索在张拉过程中的索力,可为工程参考使用。     

一种小型化双频天线的设计

在传统微带天线的基础上提出了一种单层方形微带天线的设计,通过在矩形贴片上增加支节实现天线的双频工作。仿真结果表明该天线圆极化性能良好,结构尺寸比常规的微带天线有所减小。制作并实测了该天线的实物模型,实测结果验证了仿真结果的有效性。     

Micro-generation technology assessment for housing technology

Micro-generation is defined as a notion of simultaneous generation of both heat and power in an individual dwelling. It offers an elegant and economically viable way to meet the residential power/thermal loads and Kyoto targets by demonstrating superior environmental performance with high efficiency and low harmful greenhouse gas emissions. However, before introducing micro-generation systems in large quantities a number of issues should be resolved in terms of system integration, interconnect, reliability and safety.Two demonstration houses were built at the Canadian Centre for Housing Technology that have the capability of assessing different energy and building technologies under real-life conditions. A project was initiated involving a consortia of Canadian electric and gas utilities, Canadian Government agencies and Canadian fuel cell manufacturers to modify one of two existing research houses and to integrate a prototype micro-generation unit in it that would provide electricity and heat to the house, and supply surplus electricity back to the grid. The key research objectives were assessment of building integration, micro-generation system design issues and system performance characteristics. A Stirling engine micro-generation unit, fuelled by natural gas, was used for this demonstration. The unit had an electrical output of 736 W_e and a thermal output of 6.5 kW_th. The Stirling engine was connected in parallel to the grid and the residual heat from the engine was utilized through a specifically designed heat utilization module.The paper discusses the micro-generation system performance in two different setups and scenarios that were tested over the 2003 winter/spring seasons. Data showed that the micro-generation unit was able to satisfy all of the space and water heating loads to the house during the testing period. The unit provided a considerable percentage of the house’s electrical requirement, and even exported, in a few instances, some electricity back to the grid.     

Information technology

An important message from the presented results is that neither of the systems is better or worse. The suitability of gas and electric heating depends on the circumstances where these systems are applied. Both electricity and gas have advantages and disadvantages, which are listed, and are most sensibly used only when working together