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《低温物理学报》2015,(5)
高温超导带材的各向异性特性一直影响着它工程使用中性能的充分发挥,为了提高带材的利用率,本文提出了一种基于阶梯电流的优化方法,利用MATLAB对YBCO高温超导储能单螺管磁体的结构进行优化获得初步模型,对双饼线圈进行分组,以两阶梯电流和三阶梯电流为例对磁体进行了优化.分析了各组双饼线圈的磁场分布和临界电流,计算了各部分带材性能的利用率.利用有限元软件分析阶梯电流引起的磁场变化,在充分考虑带材的临界特性和各向异性的前提下优化各组线圈的电流大小.仿真计算表明,和统一电流磁体相比,采用阶梯电流法能够优化磁体磁场构型,提高平均储能密度,最终提高磁体带材的利用率从而提升储能.阶梯电流法同样适用于多螺管磁体,对于超导储能磁体的优化是一种行之有效的方法. 相似文献
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电缆核磁共振测井仪探测特性研究 总被引:8,自引:5,他引:3
磁场形状和分布对核磁共振测井仪探测特性有决定性的作用. 该文利用电磁场有限元方法,模拟分析了国际主流核磁共振测井仪MRIL-P、CMR、 MREx、以及MR Scanner等4种仪器的磁场分布,考察了探头结构参数对磁场分布的影响,并进一步分析了仪器探测特性及其影响因素,同时对探头磁场形状进行了优化匹配,确定了探头的结构设计,并对比分析了4种探头之间的优缺点. 结果表明,梯度磁场方案优于均匀磁场方案; 居中型探头结构相对简单,信号量大,但其测量信号受钻井液影响; 贴井壁型探头结构相对复杂,信号量较小,但其设计灵活,测量信号不受钻井液影响. 相似文献
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非平衡磁控溅射镀膜机中的磁场分布对镀膜有着重要的影响。介绍一种利用有限元法求解非平衡磁控溅射镀膜机中带电线圈所产生的磁场的方法。根据电磁场理论,推导出求解带电线圈所产生的磁场的计算模型,利用基于有限元法的ANSYS软件对非平衡磁控溅射镀膜机中线圈所产生的磁场分布进行了数值模拟。通过与实测值进行比较,验证了计算模型和计算结果的可靠性。总结了非平衡磁控溅射镀膜机中的磁场分布情况,为优化镀制薄膜设计方案和提高薄膜质量提供了参考依据。 相似文献
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高温超导带材的出现,使超导储能磁体能以更高的性价比应用于工程中,然而YBCO的各向异性使带材整体的利用率较低,储能潜力没很好开发出来。本文通过ANSYS maxwell建立磁体有限元模型,结合YBCO带材的临界电流特性以及磁体上"坏点"的位置分布规律,提出一种新磁体结构即阶梯填充系数结构。与初始储能磁体相比,优化后双阶梯填充系数磁体最大径向磁场值降低14.08%,储能提高24.88%;三阶梯填充系数磁体最大径向磁场值降低44.52%,储能提高67.17%。在此基础上进行了磁体机械稳定性检验,结果表明,机械稳定度约达80%,可稳定运行。 相似文献
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本文对波荡器(Wiggler)入口区绝热压缩磁场分布对自由电子激光输出功率、增益、效率的影响,进行了非线性计算机模拟.结果表明:磁场幅值沿轴向接立方函数分布,比通常采用的正弦平方函数和平方函数这两种分布更好,更接近实验值. 相似文献
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为了研究激光鞘场中质子层的尺寸对质子束特性的影响,本文应用中国工程物理研究院 激光聚变研究中心的二维Particle-In-Cell (2D-PIC)数值模拟程序Flips2D进行了相关数值模拟研究. 研究了质子束总能量随时间的变化,得出了加速持续过程与激光脉冲持续时间的关系; 研究了质子层的宽度对加速后质子束发散角和能谱的影响;研究了质子层的厚与加速后质子束 发散角和能谱的关系;得出了质子层的初始尺寸对加速后质子特性的影响规律. 相似文献
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In this paper, the 2-D electrostatic field software, POISSON, is used to calculate the characteristic impedance of a BPM (beam position monitor) for a high current proton linac. Furthermore, the time-domain 3-D module of MAFIA with a beam microbunch at a varying offset from the axis is used to compute the induced voltage on the electrodes as a function of time. Finally, the effect of low 13 beams on the induced voltage, the sensitivity and the signal dynamic range of the BPM are discussed. 相似文献
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The aim of this study is to analyze the effect of proton and ion beam treatment on injection molded plastic parts. We employed cyclic olefin copolymers (COCs) as a resin for the manufacturing. A light guide panel was designed and fabricated via injection molding. The size and fluence of ions were changed for the analysis. The physical and chemical properties of the samples irradiated with proton and nitrogen ion beams were investigated through UV–Vis spectroscopy, FT-IR, differential scanning calorimetry (DSC), nanoindentation, residual stress, and electrical analyses. The penetration behavior of ion beams was modeled numerically, and the injection molding process was simulated. The finding showed that the irradiation of proton and nitrogen ion beams led to a change in the chemical structure and energy level of the samples. We anticipate that this study could provide a meaningful strategic way to engineer a polymeric part for broader applications using proton and ion beams. 相似文献
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M. Roth A. Blazevic E. Brambrink M. Geissel T. E. Cowan J. Fuchs A. Kemp H. Ruhl P. Audebert J. Cobble J. Fernandez M. Hegelich S. Letzring K. Ledingham P. McKenna R. Clarke D. Neely S. Karsch D. Habs J. Schreiber 《Hyperfine Interactions》2005,162(1-4):45-53
Intense beams of protons and heavy ions have been observed in ultra-intense laser-solid interaction experiments. Thereby,
a considerable fraction of the laser energy is transferred to collimated beams of energetic ions (e.g. up to 50 MeV protons;
100 MeV fluorine), which makes these beams highly interesting for various applications. Experimental results indicate very
short pulse duration and an excellent beam quality, leading to beam intensities in the TW range. To characterize the beam
quality and its dependence on laser parameters and target conditions, we performed experiments at several high-power laser
systems. We found a strong dependence on the target rear surface conditions allowing to tailor the ion beam by an appropriate
target design. We also succeeded in the generation of heavy ion beams by suppressing the proton amount at the target surface.
We will present recent experimental results demonstrating a transverse beam emittance far superior to accelerator-based ion
beams. Finally, we will discuss the prospect of laser-accelerated ion beams as new diagnostics in laser-solid interaction
experiements. Special fields of interest are proton radiography, electric field imaging, and relativistic electron transport
inside the target. 相似文献
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Chang Fu Dee Ishaq Ahmad Yan Long Zhou Xingtai M.M. Salleh B.Y. Majlis 《Physica E: Low-dimensional Systems and Nanostructures》2011,43(10):1857-1862
Study of proton beam induced welding of multiwall carbon nanotubes (MWCNTs) with ZnO nanowires (NWs) has been carried out by proton (H+) beam irradiation. The samples were irradiated by 70-keV proton (H+) ion beams at different substrate temperatures. The irradiation-induced defects in CNTs and ZnO NWs were greatly reduced at elevated temperature. The crystalline structure of ZnO NWs and MWCNTs were found to remain stable after the irradiation at 700 K. As a preparation step, a coupling of two parallel ZnO NWs with irradiation has also been demonstrated. The welding mechanisms of MWCNTs and ZnO NWs were also been suggested. These two welding processes between same and distinct nanostructures to form homo- and hetero-junctions have provided an opportunity to mass produce interconnecting one-dimensional structures used for the manufacturing of future nanowire-based electronic circuits and devices. 相似文献
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Dielectric microspheres can confine light in a three-dimensional (3D) region called photonic nanojet is shown when they are illuminated by different polarized beams. The influence of incident light polarization on photonic nanojet using the finite-difference time-domain (FDTD) method is demostrated. The axial field intensity profiles of photonic nanojets for both the linear and circular polarization incident beams are very similar. Azimuthal polarization incident beam induces a doughnut beam along the optical axis, while the radial polarization incident beam permits one to reach an effective volume as small as 0.7(λ/n) 3 . 相似文献
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Tahir NA Kain V Schmidt R Shutov A Lomonosov IV Gryaznov V Piriz AR Temporal M Hoffmann DH Fortov VE 《Physical review letters》2005,94(13):135004
The Large Hadron Collider (LHC) at CERN will generate two extremely powerful 7 TeV proton beams. Each beam will consist of 2808 bunches with an intensity per bunch of 1.15x10(11) protons so that the total number of protons in one beam will be about 3x10(14) and the total energy will be 362 MJ. Each bunch will have a duration of 0.5 ns and two successive bunches will be separated by 25 ns, while the power distribution in the radial direction will be Gaussian with a standard deviation, sigma=0.2 mm. The total duration of the beam will be about 89 mus. Using a 2D hydrodynamic code, we have carried out numerical simulations of the thermodynamic and hydrodynamic response of a solid copper target that is irradiated with one of the LHC beams. These calculations show that only the first few hundred proton bunches will deposit a high specific energy of 400 kJ/g that will induce exotic states of high energy density in matter. 相似文献
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Li CK Séguin FH Frenje JA Rygg JR Petrasso RD Town RP Amendt PA Hatchett SP Landen OL Mackinnon AJ Patel PK Tabak M Knauer JP Sangster TC Smalyuk VA 《Physical review letters》2007,99(1):015001
Monoenergetic proton radiography was used to make the first measurements of the long-time-scale dynamics and evolution of megagauss laser-plasma-generated magnetic field structures. While a 1-ns 10(14) W/cm2 laser beam is on, the field structure expands in tandem with a hemispherical plasma bubble, maintaining a rigorous 2D cylindrical symmetry. With the laser off, the bubble continues to expand as the field decays; however, the outer field structure becomes distinctly asymmetric, indicating instability. Similarly, localized asymmetry growth in the bubble interior indicates another kind of instability. 2D LASNEX hydrosimulations qualitatively match the cylindrically averaged post-laser plasma evolution but even then it underpredicts the field dissipation rate and of course completely misses the 3D asymmetry growth. 相似文献