自均衡线性相位高温超导滤波器的设计

针对第三代移动通信CDMA 2000标准用超导滤波器的技术要求,设计了一种自均衡线性相位高温超导滤波器,给出了14阶三个交叉耦合的CQ结构滤波器理论计算结果、等效电路、耦合矩阵,设计的滤波器中心频率为830MHz,65%带宽内的群时延波动优于±10ns,滤波器模拟仿真结果与理论计算很好得吻合。     

高温超导磁体临界电流的磁矢量分析法及其验证

临界电流是高温超导磁体的关键参数,文中提出了一种名为“磁矢量分析法”的高温超导临界电流计算方法.这种方法以高温超导带材性能测试结果为依据,以有限元仿真软件为手段,通过对计算高温超导磁体内部电磁感应强度矢量的分布,采用插值运算来确定高温超导磁体的临界电流.通过在77K温度下进行1:1的磁体实验,磁矢量分析法的可行性得到了验证.     

基于线性霍尔传感器的太阳能磁悬浮演示仪

应用电磁学理论、机械力学以及电子技术自制了一套太阳能磁悬浮演示仪,该演示实验仪由太阳能电池供电,利用线性霍尔传感器来探测悬浮物体的位移,以达到控制悬浮的目的,添加数码管电压显示电路,可以定量显示电磁铁的磁性在悬浮过程中随悬浮物位置变化的自动调整,能精确而直观地演示磁悬浮的物理现象该仪器结构简单、性能稳定、操作方便,能广...     

超导倒挂模型的引力特性研究

通过不同条件下的悬浮力测量实验,研究冷却条件、场冷距离、轴距对单磁体式超导倒挂模型的引力特性的影响,在确定悬浮力的有限元仿真方法可行的基础上,仿真得到组合磁体式超导倒挂模型中不同磁极组合形式下的超导引力特性。实验和仿真结果表明:场冷的退磁过程能够获得较宽的超导引力区域,且场冷距离越小,轴距越小,组合磁体的磁极数越少,引力极大值越大。     

On some consequences of an external magnetic field applied to HTS coils

A computational model which enables to evaluate the distribution of the critical currents, electric fields and the voltage in the winding of a solenoidal high temperature superconducting (HTS) magnets subjected to an external magnetic field parallel with the magnet axis, was developed. The model comes out from the well-known power law between the electric field and the transport current of the HTS tape short sample. It allows to predict the voltage–current V(I) characteristics of both the pancake coils and the complete magnet. The model was applied to the magnet system consisting of 22 pancake coils made of multifilamentary Bi(2223)/Ag tape at 20 K, which is subjected to an external uniform magnetic field parallel with the coil axis. A rather unexpected behavior of the magnet at different operating conditions (operating current and external magnetic field strength) is predicted, analyzed and reported together with a theoretical explanation. On one hand, the external uniform magnetic field parallel with the coil axis increases the resulting magnetic field strength, however, on the other hand it simultaneously decreases the angle between the resulting magnetic field and the tape surface. Thus, the effect of higher magnetic loading caused by the presence of an external magnetic field strength which is acting on individual turns located close to the coil’s flanges is compensated by more favorable orientation of the tape with respect to the resulting magnetic field. As a result, increase in the critical currents of these turns is expected. Further, the results indicate, that in case of the high field HTS insert coils the anisotropy in the I_c(B) characteristic does not play a substantial role. As a consequence, the technology of the production of the tapes for high field insert HTS coils should concentrate rather on the tapes having the current carrying capacity as high as possible, than on the attempt how to decrease the anisotropy in the I_c(B) by changing the architecture of the filaments in the tape.     

Numerical and experimental investigation of laser propulsion

Aiming at the application of laser propulsion to stratospheric flight, we propose here a repetitive propulsion system, friction-less environment and metal-free ablation in a water cannon target. A special reservoir of water is proposed to supply a definite amount of water only at the time of laser irradiation. This system is tested for the object levitated on the airflow, which is called air-slider in order to simulate friction-less environment. In order to avoid the evaporation and freezing of water in lower atmospheric pressures, we propose here an air curtain system. We have performed simulations and experiments and confirmed that a small amount of air flow can sustain the high pressure inside the water reservoir. PACS 42.62.Cf; 52.38.Mf; 07.87.+v     

跑道形高温超导转子磁体设计与测试

基于前期开发的60 kW风力发电机样机,设计并制造了两个应用于直驱式风力发电机的转子磁体,包括磁体的电磁设计、结构设计及制备流程,磁体为两种形式的跑道形高温超导磁体。通过在77 K液氮温区的直流测试,获得了磁体的临界电流、电阻等参数,及电流-电压变化曲线;通过磁体在30 K氦气低温传导冷却系统中直流励磁测试,获得了系统降温曲线、磁场随电流的变化曲线。测试结果表明,磁体满足励磁和传导冷却要求,验证了磁体设计的合理性和运行的可靠性。     

斯特林制冷机与高温超导滤波器集成及降温试验

介绍了一种高效斯特林制冷机与移动通信基站用高温超导滤波器耦合集成系统设计及降温试验;详细描述了集成系统结构设计时主要考虑因素、整体方案设计,并进行了耦合集成和性能试验;实验结果表明,制冷机对其应用背景具有良好的匹配性。     

基于H方程的超导磁悬浮系统悬浮特性分析

高精度的重力测量在地震监测、资源勘探、惯性导航等领域均有着十分重要的意义,将超导磁悬浮系统应用于重力测量可以极大提高重力测量的精度,减少漂移率。当前对超导重力仪内磁悬浮系统的仿真主要采用A方程静磁场法,仿真得到的数据与实验结果相差较大,为了提高仿真精度和效率,采用H方程在COMSOL中建立了新的仿真模型,仿真得到的数据与实验结果偏差较小,验证了该方法可以提高超导磁悬浮系统的仿真精度和效率。仿真得到了超导重力仪内磁悬浮系统的磁场分布,屏蔽电流分布,受力,穿透深度等特征,分析了超导球在磁场中受到的悬浮力与悬浮高度、悬浮线圈电流大小、通入速率的关系,计算得到了超导磁悬浮系统的磁力梯度。     

高温超导空心变压器椭圆磁场计算分析

变压器的磁场研究对于高温超导变压器的设计具有非常重要的意义,尤其是对高温超导空心变压器。由于每一条磁力线均直接作用于线圈,因此磁场对高温超导空心变压器临界电流和交流损耗磁场的影响更为显著。文中通过数学计算,得出高温超导空心变压器在其空间任一点产生的磁场为形状和大小,论证了该磁场为带旋转分量的椭圆形磁场,并通过有限元仿真验证计算结果。     

New aspects of energy transfer from an alternating magnetic field to a pendulum with ferromagnetic suspension

New data are presented about energy transfer from an alternating magnetic field to a pendulum with ferromagnetic suspension. For each frequency of the alternating magnetic field there is a certain field intensity for which energy transfer is maximum.     

一元线性问题中的实验标准差

分析了用不同方法处理具有一元线性函数关系的物理实验数据的实验标准差．结果表明,在n≥4时,用逐差法计算线性系数6的实验标准差明显小于简单平均值法,但是稍大于最小二乘法     

Ultrasonic investigation of magnetic nanoparticles suspension with PEG biocompatible coating

Water suspension of nanoparticles was studied by ultrasound spectroscopy. Nanoparticles have a core-shell structure with magnetic core Fe₃O₄ and surfactant shells. The surface of magnetic particles was coated with oleate sodium as the primary layer and polyethylene glycol as the secondary layer. The acoustic properties of suspensions, such as velocity and attenuation of ultrasonic waves, have been measured. From experimental data mechanical properties have been determined. Adiabatic compressibility of nanoparticles suspension decreased with increase of temperature. The changes of ultrasonic wave attenuation under the influence of the external magnetic field, show that magnetic liquids with high concentration of magnetic material (despite two surfactant shells) show tendency to aggregate.     

电磁感应与磁悬浮力实验的设计

利用电磁感应实验仪,开设了电磁感应与磁悬浮力、电磁感应与各种材料的关系和电磁感应中感应电场及能量的转换等内容的实验,较好地演示了电磁感应和磁悬浮相关原理.     

Exact soliton solution of spin chain with an external magnetic field in linear wave background

Employing a simple, straightforward Darboux transformation we construct exact N-soliton solution for anisotropic spin chain driven by an external magnetic field in linear wave background. As a special case the explicit one- and two-soliton solution dressed by the linear wave corresponding to magnon in quantum theory is obtained analytically and its property is discussed in detail. The dispersion law, effective soliton mass, and the energy of each soliton are investigated as well. Our result show that the stability criterion of soliton is related with anisotropic parameter and the amplitude of the linear wave.     

高温超导感应电机分析与仿真

将一个320kW的普通鼠笼式感应电机进行改造,分别采用两种不同的高温超导材料Bi-2223/Ag和YBCO,替代原电机的导条和端环。采用等效电路的分析方法,并结合能在较宽的电场强度与电密范围内描述超导材料特性的Weibull函数,分析超导感应电机性能。分析表明,超导感应电机的启动转矩有明显提高,且稳定后可达到同步速,稳定运行效率提高。进一步对这两种不同材料对电机的影响进行分析,表明采用YBCO的电机性能更好。最后对电机的暂态过程进行仿真。     

高温超导飞轮储能系统磁悬浮力的仿真计算与实验分析

超导磁悬浮飞轮储能装置储能密度大、储能效率高,具有很好的发展前景。阐述了超导磁悬浮飞轮储能装置的基本原理。主要研究了超导块与永磁体之间的间隙、两者的半径和永磁体厚度等尺寸参数对磁悬浮力的影响。运用有限元分析软件ANSYS对磁悬浮的基本模型进行仿真计算,得到模型的磁力线分布,进一步总结各个参数和磁悬浮力之间的关系,并进行实验验证得到的结论。     

苯酚和邻苯二酚同步及导数—同步荧光光谱解析

本文用拟面积多波长数据线性双组合、双峰倍增配平、多波长生回归和导数（一阶、二阶）解析苯酚和邻苯二酚混合物的同步荧光光谱，建立了五种同时测定混合物中苯酚和邻苯二酚的新荧光分析方法。     

基于ANSYS的供电频率对高温超导直线感应电机性能影响的分析

通过对高温超导直线电机的理论分析,从内部电磁场的角度出发,研究供电频率的变化对高温超导直线电机的各项电磁性能影响。利用ANSYS有限元分析软件对电机的电磁场、电磁推力以及热损耗进行仿真,并对仿真结果进行简要说明。文中的研究结果对高温超导直线感应电机的运行参数设计提供了理论依据和分析基础。     

Acoustic wave in a suspension of magnetic nanoparticle with sodium oleate coating

The ultrasonic propagation in the water-based magnetic fluid with doubled layered surfactant shell was studied. The measurements were carried out both in the presence as well as in the absence of the external magnetic field. The thickness of the surfactant shell was evaluated by comparing the mean size of magnetic grain extracted from magnetization curve with the mean hydrodynamic diameter obtained from differential centrifugal sedimentation method. The thickness of surfactant shell was used to estimate volume fraction of the particle aggregates consisted of magnetite grain and surfactant layer. From the ultrasonic velocity measurements in the absence of the applied magnetic field, the adiabatic compressibility of the particle aggregates was determined. In the external magnetic field, the magnetic fluid studied in this article becomes acoustically anisotropic, i.e., velocity and attenuation of the ultrasonic wave depend on the angle between the wave vector and the direction of the magnetic field. The results of the ultrasonic measurements in the external magnetic field were compared with the hydrodynamic theory of Ovchinnikov and Sokolov (velocity) and with the internal chain dynamics model of Shliomis, Mond and Morozov (attenuation).