共查询到20条相似文献,搜索用时 765 毫秒
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介绍了兰州重离子冷却储存环主环(CSRm)的改进W型二极磁铁和实验环(CSRe)C型二极磁铁的磁场计算和物理设计,在降低了磁铁造价和运行费用的前提下设计参数达到或超过了物理要求.根据样机的加工和检测结果来看,所有的磁场计算和物理设计的结果是可靠的.Magnetic field calculation and design of CSRm modified W-type dipoles and of CSRe C-type dipoles are presented in this paper. Under the condition of lower cost, all of the designed parameters are better than required values. Now the prototype has been fabricated and also the magnetic field measurement has been done. According to the measured results, all the calculation and design are very reliable. 相似文献
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中国工程物理研究院流体物理研究所目前正在建造一台医用11 MeV回旋加速器,该加速器磁铁采用小气隙、深谷结构以提供更高的平均磁场和更强的聚焦能力。为实现510-4的测量精度,自行研发了一套磁场点测装置,该装置可实现二维极坐标下的精确测量。经过多次磁场垫补,束流的相位偏移控制在9,一次谐波幅值控制在0.001 T以内,满足了磁铁的设计需求。在束流调试过程中,成功实现了质子束的引出,表明回旋加速器磁铁建造成功。此外,还对磁铁研制过程中出现的磁场缺陷及磁测误差进行了讨论。 相似文献
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首先叙述了由单个轴向磁化环所产生的磁场,并就两个永磁环所产生的纵向磁场进行了分析.对于两个沿同一方向磁化的永磁体环,沿磁环中心线将会产生一个强度较为均匀的轴向磁场.如果两者的磁化方向相反,则在两磁铁间的区域将产生一个纵向的梯度磁场,其磁场强度介于-B0到+B0之间.设计制造了一个高梯度的轴向磁场,其磁场梯度为47.2Tm,测量结果与计算结果非常一致.文中还讨论了产生变梯度磁场的方法.由于永磁环所产生的磁场和螺线管的磁场较为相似,磁铁外部空间将有较大的漏场,最后还讨论了屏蔽漏场的问题. 相似文献
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介绍了强流重离子加速器装置HIAF(High Intensity heavy-ion Accelerator Facility)项目增强器BRing(Booster Ring)快脉冲二极磁铁的性能指标、测量要求和测量方法,描述了快脉冲二极磁铁稳态磁场测量系统及动态磁场测量系统的构成。在稳态磁场测量中,为提高积分磁场测量精度和测量效率,长线圈测量系统采用了on fly技术;在动态磁场测量中,研制了用于磁场延迟及磁场畸变测量的矩阵线圈。通过样机磁铁的测量,完成了测量系统的性能指标验证和磁铁的稳态磁场测量。实测结果表明,样机磁铁的设计和制造均达到了预期指标,并依据测量数据完成了磁铁的二次削斜。 相似文献
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Tim?Langen Michael?Gring Maximilian?Kuhnert Bernhard?Rauer Remi?Geiger David?Adu?Smith Igor?E.?Mazets J?rg?Schmiedmayer
In magnetohydrodynamics, model experiments are commonly conducted to investigate the interaction between magnetic fields and electrically conductive fluids. The available flow instrumentation for opaque fluids usually lacks the ability to capture and visualize a velocity field in one shot. We present a multidimensional ultrasound array Doppler velocimeter that employs multiple line arrays of transducers and allows the resolution of small scale structures in complex flows. The system achieves a lateral resolution up to 3 mm, an axial resolution of approx. 1.4 mm and frame rates up to 30 Hz in metal melts at room temperature. A flexible sensor arrangement allows for various measurement configurations, e.g. four planes can be measured simultaneously with one velocity component, two planes with two components or two lines with three components. We present an experiment in a square-shaped container driven by a rotating magnetic field and results of a model experiment for continuous steel casting. The measurement system has proven to be a powerful tool for research in magnetohydrodynamics. 相似文献
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《Current Applied Physics》2014,14(7):936-940
Arc rotation velocities of a plasma centrifuge with a counter-rotating electrical discharge were measured by using double probes placed perpendicular to each other. The measurement results were compared with the results calculated from the analytic solutions suggested by Hong et al. The comparison revealed that the arc column near the electrodes can be rotated much faster by increasing the arc currents and magnetic fields. For example, the rotational velocity of the are column near the electrodes was increased from 75 to 150 m/s with the increase of magnetic flux density from 15 to 45 mT at the fixed arc current of 50 A. On the other hand, the rotational velocity of the arc column showed only negligible changes at the plane of symmetry, where the radial component of the arc current was designed to become zero due to the symmetry of the counter-rotating electrical discharge. From these measurement results and analytic solutions, gaseous mixtures of different masses can be separated effectively near the electrode regions of a plasma centrifuge with a counter-rotating electrical discharge. 相似文献
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P. V. Artel’nyi A. L. Virovlyansky A. Yu. Kazarova P. I. Korotin L. Ya. Lyubavin A. V. Stulenkov 《Acoustical Physics》2018,64(2):175-185
The paper presents the results of processing measurement data on the spatiotemporal structures of sound fields in Lake Ladoga. Measurements were taken with an extended vertical receiver array. The aim of processing was to isolate the field components that were stable with respect to small variations in the waveguide parameters. Since a model of the medium is inevitably inaccurate, such components can be predicted with greater accuracy than the total field. In terms of the ray approach, a stable component is generated by a beam of rays propagating over close trajectories. The discussed experiment analyzed sound fields excited by a point source that emitted wideband pulses, as well as the fields of wave beams excited by the emitting vertical array at fixed frequencies. In both cases, the processing results showed that the isolated stable components, as expected, coincide substantially better with the prediction of theoretical calculation (by the wide angle parabolic equation method) than with the total wave field. 相似文献
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油井含水率是油田开发过程中的一个重要指标。光纤传感器具有体积小、重量轻、抗干扰能力强、实时、高效、准确等优点,将其应用于石油测井,有利于提高勘探效率。介绍测井应用中原油含水率计量仪的结构,分析了光纤传感器对混合液体含水率测量的基本原理。激光在弯曲光纤中的传输效率随外界混合介质折射率的变化而改变,根据光纤输出光功率的大小可以测量外界混合介质的组成成分。通过数值模拟,给出了光纤传感器中光束强度随混合液体含水率的变化现象,计算得到混合液体中含水率测量结果。结果表明,光纤传感器计量仪能实现0%~100%含水量的连续测量。最后基于数值模拟结果讨论了系统设计中的注意事项。 相似文献
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A simple fiber sensor for magnetic field measurement based on nanoparticle Fe(3)O(4) magnetic fluid and relative Fresnel reflection is presented. The sensor includes only a light source, three couplers, two photodetectors, and two fiber sensing ends. Magnetic fields at different concentrations of magnetic fluid are measured. Magnetic fluid with high concentration can be used for the measurement of weak magnetic fields, while low concentration fluid is used for the measurement of strong magnetic fields. The temperature dependence of the sensor is also addressed. 相似文献
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Fractional Fourier transform (FRFT) plays an important role in many fields of optics and signal processing. This paper considers the problem of real-time measurement of the spectrum of a signal in the FRFT domain. In this paper, we propose two approaches for real-time measurement of the FRFT of a signal based on modulation and bandpass filtering systems. The relation is established between the linear frequency modulation (LFM or chirp) spectrum and the FRFT of its envelope. In addition, two applications for spectrum measurement are presented in the FRFT domain. The LFM signal can be bandlimited in the Fourier transform (FT) domain through spectrum measurement associated with bandpass filtering method. The results can also be useful in the problems related to swept-frequency filter for measurement in the FRFT domain. 相似文献
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To analyze the complex three-dimensional flow structure of an axial flow fan and determine the validity of its application, PIV is used to provide detailed space and time resolved experimental data for understanding and control of flow field. The high resolution stereoscopic PIV system was successfully employed in this study for the investigation of flow structure around the axial flow fan. Using the once-per-revolution signal from the rotor, image fields were captured at a fixed position of the blades and hence provides the ability to do phase-averaging. The three-dimensional instantaneous velocity fields, phase-averaged velocity fields, instantaneous and mean vorticity distributions of the stereoscopic PIV measurement results were represented at typical planes of the flow field. Phaseaveraged velocity fields were calculated based on 200 frames of the instantaneous stereoscopic PIV measurement results. From the velocity distribution, the vorticity and turbulent intensity distribution, which are known to be major factors of fan noise, were calculated and its diffusion was discussed as they travel downstream. From the reconstructed three-dimensional velocity iso-surface at 8 cross planes of the outlet flow fields, the three-dimensional features can be seen clearly. 相似文献
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《Waves in Random and Complex Media》2013,23(4):682-707
We develop a new theory of the optical theorem for scalar fields in nonhomogeneous media which can be bounded or unbounded. It applies to arbitrary lossless backgrounds and quite general probing fields. The derived formulation holds for arbitrary passive scatterers, which can be dissipative, as well as for the more general class of active scatterers which are composed of a (passive) scatterer component and an active, radiating (antenna) component. The generalization of the optical theorem to active scatterers is relevant to many applications such as surveillance of active targets including certain cloaks and invisible scatterers and wireless communications. The derived theoretical framework includes the familiar real power optical theorem describing power extinction due to both dissipation and scattering as well as a novel reactive optical theorem related to the reactive power changes. The developed approach naturally leads to three optical theorem indicators or statistics which can be used to detect changes or targets in unknown complex media. The paper includes numerical simulation results that illustrate the application of the derived optical theorem results to change detection in complex and random media. 相似文献
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The reciprocity measurement theory in anomalous reverberant sound fields was investigated.An improved method Was proposed due to the interrelated errors.The source volume velocity Was corrected by spatial average of measurement results and evaluation of the reverberant sound field influence on acoustic energy density.The result was validated in underwater experiment,corrected reciprocity measurement results were almost the same as direct measurement results.It indicates that reverberant sound field does not affect the validitv of the principle,but influences the obtainment of source volume velocity,then influences the measurement of transfer functions with the principle.The proposed method is simple and effective in anomalous reverberant sound fields.The study mav be valuable for the applications which are based on the principle. 相似文献