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1.
本文针对托卡马克装置中超导载磁体的磁弹性弯曲与稳定性问题,动用Biot-Savart定律和曲梁弯曲理论,给出了其环向磁场的超导载流线圈结构在自身电流产生的磁力作用下的磁弹性力学模型。  相似文献   

2.
本文针对托卡马克装置中超导载流磁体的磁弹性弯曲与稳定性问题,运用Biot-Savart定律和曲梁弯曲理论,给出了其环向磁场的超导载流线圈结构在自身电流产生的磁力作用下的磁弹性力学模型。所得到的控制方程反映了磁场与线圈变形之间的非线性耦合作用,全面描述了结构的轴向拉伸、绕轴扭转、面内弯曲和面外弯曲等各种变形模式。本文采用半解析半数值方法对控制方程进行了定量求解,获得了有关线圈形变和内力分布的定量结果。通过其面外弯曲变形与外加电流的非线性关系,应用Southwel图,给出了线圈在磁弹性相互作用下发生磁弹性失稳的临界电流值,并讨论了临界电流随环向磁场线圈个数变化的规律  相似文献   

3.
李兰凯  王厚生  倪志鹏  程军胜  王秋良 《物理学报》2013,62(5):58403-058403
为了增加超导线圈中导线的占空比, 提高超导磁体正常运行时的机械稳定性, 通常在超导线圈绕制过程中施加一定的绕制张紧力. 绕制张紧力的大小会对超导磁体的失超特性和退化性能产生重要的影响, 因此有必要对绕制过程中的机械应力进行详细的分析. 本文仔细地分析了绕制过程中导线的受力情况, 进行了一些合理的假设和近似, 提出了研究超导线圈绕制应力的理论模型, 并根据轴对称结构的弹性力学方程式推导了计算超导线圈应力应变分布的理论公式. 基于该模型分别研究了单一绕组的超导线圈和双绕组的超导线圈的绕制应力, 分析了绕制张紧力和绕组的各向异性特性对径向应力和环向应力的影响. 在该理论模型分析结果的基础上可以进一步分析多物理场作用下的超导磁体的应力应变行为, 为高性能超导线圈的设计和建造提供理论指导. 关键词: 超导线圈 机械稳定性 绕制张力 应力  相似文献   

4.
三线圈超导磁体在脉冲电流下的动力稳定性分析   总被引:2,自引:1,他引:1  
对于聚变反应堆中超导载流磁体在稳态电流基础上受到脉冲电流影响时的动力稳定性给出了定量分析方法。结合其超导载流磁体的实验结构,给出了超导磁体在不同稳态工作电流(即低于稳态的磁弹性人稳临界电流)作用下受到矩形脉冲电流作用 磁弹性动力响应的数值模拟结果。在此基础上,给出了关于稳态工作电流、脉冲电流强度和脉冲持续时间等参数的磁弹性动力稳定性参数范围。  相似文献   

5.
核磁共振成像和核磁共振谱仪是高场超导磁体的主要应用领域.高场超导磁体通常具有较高的磁场和运行电流,在运行过程中超导线会产生较高的电磁应力,其临界特性将发生退化,影响磁体的稳定性.开展高场超导磁体的电磁应力精确分析显得尤为必要.本文发展了一种快速有效的有限元分析方法,第一步,为整个超导磁体系统建立平均有限元模型,采用传统的电磁-结构耦合方法求解电磁应力,获得最大应力位置;第二步,对最大应力所在的超导线圈建立详细有限元模型,采用单积分-结构分析方法精确求解每一组分中电磁应力.基于该模型研究了500 MHz NMR超导磁体的电磁应力.该分析方法也可以用于超导磁体冷却过程中的热应力分析.为高场超导磁体设计和建造提供有益的理论依据.  相似文献   

6.
超导导体的力学性能是决定导体载流性能的重要影响因素之一,构成超导磁体的超导电缆在运行过程中受电磁力、热应力的作用,会导致其内部超导线产生应变,进而影响其载流性能和交流损耗,因此研究电磁循环载荷对超导电缆的影响有着重要的意义。对国际热核聚变实验堆中极向场线圈中Nb Ti超导导体进行机械压缩实验,并从形变量、弹性模量、弹性功等方面,对其机械强度进行分析。该方法可以在不进行电磁循环测试的情况下快速判断导体机械性能,为导体设计提供初步性能评判依据。结果显示,PF1-6NbTi超导导体相对于测试的其他PF导体在相同工况下,累积形变量与最大形变量更小。通过进一步对导体结构设计进行对比分析,发现低空隙率以及短节距绞线可以有效提高电缆机械性能。  相似文献   

7.
电枢是电磁线圈发射器的关键能量转换部分,针对感应实体电枢、感应线圈电枢、串联载流线圈电枢和并联载流线圈电枢4种电磁发射器的发射原理和结构特点,推导了4种发射器的系统数学模型。根据等效电路方法,利用MATLAB建立仿真系统,对影响电磁线圈发射器系统特性的电枢尺寸、实体电枢材料、线圈电枢线径、电枢初始位置与初速度、多级发射器电枢位置序列等因素进行了仿真计算和比较分析。结果表明:感应电枢发射器在初级和末级驱动线圈电流下降阶段存在磁力拖拽效应,使得发射体速度在发射管出口处下降明显,而载流电枢发射器不存在拖拽效应;增大感应线圈电枢和串联载流线圈电枢线径,或减小并联载流线圈电枢线径,可以有效提高发射出口速度;载流电枢适用于低速较少级数发射系统。研究方法和结论对电磁发射器电枢结构选择和方案设计具有一定的指导意义。  相似文献   

8.
《低温与超导》2021,49(8):17-20,65
提出了一个冷孔直径150 mm、中心磁场为15 T的NbTi/Nb_3Sn超导磁体电磁结构。分析了超导磁体各线圈中磁场的分布规律,结合超导材料临界性能,得到了超导磁体的运行电磁裕度。针对线圈结构组份材料的机械性能,采用平均有限元法仿真了超导磁体的应力/应变,最大环向应力和应变分别为112 MPa和0.297%。该结果表明了超导Nb_3Sn线圈中的应力/应变处于合理水平。  相似文献   

9.
超导磁储能系统通过超导体制成的导电线圈储存能量,它的投入使用完全依赖于超导磁体的设计和研制,作为电磁储能元件,超导磁体在运行过程中会产生相当强的磁场。以储能量为1MJ的单螺管型、Bi系高温超导磁体作为研究对象,根据电磁场理论,推导出数学模型,并借助ANSYS有限元分析软件,建立了一个由44个双饼线圈构成的二维电磁分析模型,得到磁场分布规律等。该分析结果对超导磁体的结构设计、优化及漏磁屏蔽提供了一定的参考依据。  相似文献   

10.
随着超导线圈在电力领域中的应用越来越广泛,该文利用有限元仿真软件对处于交变磁场中载流高温超导带材的电-磁-力特性进行了研究,通过超导体的非线性E-J本构关系和基于棱边元法的磁场强度法来求解超导线圈内的电流分布、线圈周围的磁场分布及其受到的电磁力大小等电磁特性,重点研究了在以涂层超导磁体为励磁线圈的直线牵引系统中超导线圈和三相绕组之间的电磁力大小.基于仿真结果,分析了超导线圈内电流分布随气隙的变化关系;线圈周围的磁场分布情况及其对超导线圈临界电流的影响;线圈受到的电磁力随时间和气隙的变化关系等,所得结果为高温超导直线电机的设计和应用提供参考依据.  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

13.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

14.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

15.
16.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

17.
A transient suppression method for piezoelectric ceramic transducer is presented. By adding some special pedestal pulses to the original transmitted signal, the transient effects in the output of the transducer can be just precisely transmission by use of a narrowband transducer. canceled, thereby achieving the broadband The experimental results show that the transient responses of the sinusoid pulses and coded signals are suppressed successfully and the acoustic waveforms radiated into the surrounding water are improved significantly.  相似文献   

18.
We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.  相似文献   

19.
The(2 1)-dimensional nonlinear Schr(o)dinger(NLS)equation with spatially inhomogeneous nonlinearities is investigated,which describes propagation of light in(2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities.New types of optical modes and nonlinear effects in optical media are presented numerically.The results reveal that the regular split of beam can be obtained in (2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities,by adjusting the guiding parameter.Furthermore,the stability of beam regular split is discussed numerically,and the results reveal that the beam regular split is stable to the finite initial perturbations.  相似文献   

20.
In the real-world application of face recognition system, owing to the difficulties of collecting samples or storage space of systems, only one sample image per person is stored in the system, which is so-called one sample per person problem. Moreover, pose and illumination have impact on recognition performance. We propose a novel pose and illumination robust algorithm for face recognition with a single training image per person to solve the above limitations. Experimental results show that the proposed algorithm is an efficient and practical approach for face recognition.  相似文献   

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