一种新型机械式延时自闭水嘴的设计与操作性能分析

针对目前市场上延时自闭水嘴在操作性能上的不足, 设计了一种新型机械式延时自闭水嘴. 对该水嘴启闭过程中的操作性能和延时性能进行分析, 得到了水嘴操作力矩、延时时间与卷簧结构参数之间的函数关系, 并提出了水嘴操作力矩的大小与变动率优化模型. 以操作力轻便、稳定为指标, 得到了水嘴延时组件结构参数的最优组合解. 结果表明: 参数优化后的水嘴最大操作力矩为374N?mm, 且趋于稳定, 性能明显提高.     

电子式互感器高频数据采集与传输方案

针对当前电力系统电子式互感器采样率偏低,难以满足行波测距装置准确定位电力故障的问题,提出了电子式互感器高频信号采集与传输方案;电子式互感器内部为Rogowski 线圈,电网电流信号被其微分作用转换为小电压信号并附加了90°超前相差,设计积分电路补偿该相差;设计采样率为2 MSps的高频信号采集电路,FPGA通过LVDS接口读取采样数据,并进行幅值处理,最后利用大容量FIFO(先入先出单元)进行缓存;由于百兆网数据传输速率有限,利用FPGA设计吉比特光纤以太网传输特定格式报文,把电流数据传输至电力行波测距装置;解决了积分电路由于运放输入偏置电压带来的积分饱和问题,以及高速ADC输入量程小于输入信号幅值等技术难点;试验结果表明,高频信号采集及传输方案能够满足行波测距装置百米级别的测距精度要求,具有一定工程应用价值。     

硅基半导体芯片激光红外显微成像系统研究

为了解决可见光显微成像技术无法实现硅基芯片内部结构观测的问题,根据1 064nm的红外激光对硅材料具有一定穿透深度的特性,设计了一种硅基半导体芯片激光红外显微成像系统.该系统采用数值孔径为0.42的长工作距显微物镜,通过音圈电机振动多模石英光纤消除散斑噪音,由系统观察CD-RW盘片道间距,表明系统分辨率可达到1.6μm,接近理论值,实现了对芯片厚度为70μm的静态随机存储器内部结构显微成像的观测.     

平行共轴线圈的磁场特征研究与实验设计

通过计算机及相关的传感器和数据采集接口辅助,研究了平行共轴双线圈间距分别为0.5R,R,1.5R时,轴线方向磁场强度的分布规律及特征.从平行共轴双线圈间距为R的亥姆霍兹线圈所形成的均匀磁场出发,结合理论推导,自己设计并组装了三线圈实验装置,实现了平行共轴三线圈均匀磁场区域扩大、强度增强的实验设计,在一定程度上弥补了传统亥姆霍兹线圈磁场测量的不足并有助于对其深入的理解和研究.     

Design of SC solenoid with high homogeneity

A novel kind of SC (superconducting) solenoid coil is designed to satisfy the homogeneity requirement of the magnetic field. In this paper, we first calculate the current density distribution of the solenoid coil section through the linear programming method. Then a traditional solenoid and a nonrectangular section solenoid are designed to produce a central field up to 7 T with a homogeneity to the greatest extent. After comparision of the two solenoid coils designed in magnet field quality, fabrication cost and other aspects, the new design of the nonrectangular section of a solenoid coil can be realized through improving the techniques of framework fabrication and winding. Finally, the outlook and error analysis of this kind of SC magnet coil are also discussed briefly.     

ITERУ������Ȧ��ͷȥ���������������о�

分别采用机械打磨去镍加热镀锡工艺和反电镀去镍加电刷镀银工艺制作一对接头,然后对接头进行低温直流测试,测得前者的直流电阻为1.98n-,后者的直流电阻为1.53n-。对比分析可知,反电镀去镍和电镀银工艺更有效、更简单。这些工艺研究对ITER校正场线圈超导接头的制作具有重要指导意义。     

多级感应线圈炮最优发射控制策略

基于电路理论,建立了多级感应线圈炮数学机电控制模型;分析了电枢受力的影响因素,结果表明,电枢受力决定于驱动线圈和电枢的电流大小和它们之间的互感梯度。总结了多级同步感应线圈炮设计原则,根据设计原则,提出了感应线圈炮的最优发射控制策略,并从理论上证明其可行性,最后以10级线圈炮为例,归纳了多级感应线圈炮的触发公式,并进行了实验验证,其结果表明,通过修正触发公式,仿真结果与测量值吻合较好。     

A novel electromagnetic induction detector with a coaxial coil for capillary electrophoresis

A novel electromagnetic induction detector with two inductors for CE was described here.The two inductors were used as signal detection and reference,respectively.The parameters affecting the detector performance(including coil turns,detection distance, excitation frequency,voltage,etc.) were optimized.Under the optimum condition,the feasibility of the detector was examined by analyzing inorganic ions.The fabricated detector showed good linear relationship between the response and the analytes concentrations,with a detection limit of 13μmol/L for Na~+(S/N = 3).A variety of advantages,such as simple construction, ease of operation,and considerably universal response,suggested this novel detector a promising application prospect in analytical area.     

Multichannel transceiver dual-tuned RF coil for proton/sodium MR imaging of knee cartilage at 3 T

Sodium magnetic resonance (MR) imaging is a promising technique for detecting changes of proteoglycan (PG) content in cartilage associated with knee osteoarthritis. Despite its potential clinical benefit, sodium MR imaging in vivo is challenging because of intrinsically low sodium concentration and low MR signal sensitivity. Some of the challenges in sodium MR imaging may be eliminated by the use of a high-sensitivity radiofrequency (RF) coil, specifically, a dual-tuned (DT) proton/sodium RF coil which facilitates the co-registration of sodium and proton MR images and the evaluation of both physiochemical and structural properties of knee cartilage. Nevertheless, implementation of a DT proton/sodium RF coil is technically difficult because of the coupling effect between the coil elements (particularly at high field) and the required compact design with improved coil sensitivity. In this study, we applied a multitransceiver RF coil design to develop a DT proton/sodium coil for knee cartilage imaging at 3 T. With the new design, the size of the coil was minimized, and a high signal-to-noise ratio (SNR) was achieved. DT coil exhibited high levels of reflection S11 (～-21 dB) and transmission coefficient S12 (～-19 dB) for both the proton and sodium coils. High SNR (range 27-38) and contrast-to-noise ratio (CNR) (range 15-21) were achieved in sodium MR imaging of knee cartilage in vivo at 3-mm(3) isotropic resolution. This DT coil performance was comparable to that measured using a sodium-only birdcage coil (SNR of 28 and CNR of 20). Clinical evaluation of the DT coil on four normal subjects demonstrated a consistent acquisition of high-resolution proton images and measurement of relative sodium concentrations of knee cartilages without repositioning of the subjects during the same MR scanning session.     

跑道型Bi系高温超导双饼线圈I～E特性计算与实验研究

本文使用Ansys有限元分析软件,建立三维跑道线圈模型,考虑超导线截面电流密度的非均匀分布特性,计算Bi系高温超导双饼线圈中各区域磁场分布、临界电流分布、电流密度分布和电场分布,从而计算线圈的I～E关系曲线,为超导线圈提供一个更为准确的检验标准,对照线圈的测试结果,用此程序计算的线圈I～E关系曲线与测试曲线吻合的较好.