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论述了在交变磁场下测量磁光薄膜动态法拉第效应的原理和方法,利用此方法,在不同的调制磁场强度和频率下测量磁光薄膜的动态法拉第旋转特性,获得了较好的测量结果,并对测量误差进行了分析。 相似文献
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利用有效场理论研究了纳米管上外磁场中Blume-Capel模型格点的磁化强度、磁化率、内能、比热和自由能,得到了系统格点的磁化强度、磁化率、内能、比热和自由能与外磁场和晶场的关系.结果表明:外磁场强度、交换相互作用和晶场强度等诸多因素相互竞争,使系统表现出比没有外磁场作用的Blume-Capel模型更为丰富的磁学特性;外磁场能够增大系统格点的磁化强度,导致系统的二级相变消失;负晶场作用系统时,系统会发生一级相变;晶场强度、外磁场强度不同时,系统的磁化率、内能、比热和自由能也呈现出复杂性. 相似文献
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With the Nambu-Jona-Lasinio (NJL) model we calculate the properties of pion and σ-meson at finite temperature and finite magnetic field. The obtained temperature and magnetic field strength dependence of the constituent quark mass M, the pion and σ-meson masses and the neutral pion decay constant indicates that, in the simple four fermion interaction model, there exists the magnetic catalysis effect. It also shows that the Gell-Mann-Oakes-Renner relation is violated obviously with the increasing of the temperature, and the effect of the magnetic field becomes pronounced only around the critical temperature. The deviation of the critical temperatures obtained with different criteria indicates that the chiral phase transition driven by the temperature in the magnetic field strength region we have considered is in fact a crossover. 相似文献
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In this paper, an optimization design method for high field superconducting magnet with ferromagnetic shield is discussed. Firstly, the analytical formula for calculating the magnetic field at any space point is derived based on the equivalent magnetic charge model. Then the validity and accuracy of the formula are discussed by comparing the results with that of the finite element method (FEM)for the same model. Finally, a joint optimization of MRI magnet system with ferromagnetic shielding is carried out in order to improve the homogeneity of magnetic field in the DSV(diameter of spherical volume)region and enhance the field intensity in the center. 相似文献
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主要研究了斯格明子的质量和电荷半径在均匀磁场中的变化性质。基于系统所拥有的对称性,本研究采用一组拥有轴对称性的拟设方程式以便进行研究工作。本研究证明重子数即使在非零磁场中也是一个守恒量。本研究发现随着磁场强度的增加,斯格明子的质量和电荷半径对磁场的依赖方式不同:由于磁场的主要贡献由线性项过渡到平方项,因此随着磁场的增强,斯格明子的质量先下降然后上升;与此相对应的,随着磁场的增强,斯格明子的电荷半径先增加然后减小。最后,本研究发现磁星内部的状态方程式对磁场强度有强烈的依赖,因此在理论计算磁星的质量上限时应考虑磁场所产生的影响。The mass and shape of skyrmion in an uniform magnetic field are investigated. Base on the symmetry of the system, an axially symmetric ansatz of the soliton is proposed to perform the study. The baryon number is shown to be always conserved even in a nonzero magnetic background. It is found that with the increase of the strength of magnetic field, the static mass of skyrmion first decreases then increases, as the dominant role shift from the linear term of magnetic field to the quadratic term of magnetic field, while the soliton size first increase then decrease. Finally, in the core part of magnetar, the equation of state have strong dependence of magnetic field, which also modifies the mass limit for magnetar. 相似文献
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讨论了磁场中夸克物质的非轻子弱作用过程. 改进了在弱磁场情况下的近似计算方法, 分别给出了强弱磁场下非轻子过程的反应率的表达式, 以及一定条件下的近似表达式. 结果显示, 强磁场极大的抑制反应率的大小, 进而影响奇异夸克物质的粘滞性. 相似文献
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1.IntroductionAtpresent,therearetwokindsofpracticalrewritableopticalstorage:phase-changeoptiCalandmagneto-opticalstoraged].Magneto-opticaldatastorageisattractiveformassdatastoragebecauseofitshighrecordingdensityandthecontinuouslyincreasingdatatransferrate.DirectoverwriteisapromisingschemetoobtainhighdatatransferratellJ.Magneticfieldmodulation(MFM)andlightintensitymodulation(Lin)arethemajormethodstorealizemagneto--opticaldirectoverwrite[2-8].InLIM,pulsedlaserintensityismodulatedaccordingtot… 相似文献
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WU Liu-Po ZHOU Shi-Ping SONG Hong-Yan SHI Yao-Ming 《理论物理通讯》2007,48(5):943-948
We study electronic transport through a quantum dot (QD) with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states (LDOS) and conductance of QD are derived self-consistently. It shows that the LDOS and conductance have obvious changes with the Coulomb blockade interaction. The intensity and angle of the magnetic field or temperatures, which reflect the mesoscopic structure of the QD are derived. The superiority of this device is that the QD can be controlled easily by the magnetic field, so it is valuable to apply in generating, manipulating and probing spin state. 相似文献
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S. A. Mikhnov 《Journal of Applied Spectroscopy》2004,71(5):757-759
It has been found that the phase shift min in the synchronous detection block that ensures the minimum amplitude of the EPR lines of ruby, diphenylpicrylhydrazyl, and MnSO4·5H2O, depends on the amplitude of the modulationH
m of a stationary magnetic field. The dependence of min on H
m is explained by the inertial nature of the recovery of the stationary states of paramagnetic centers on a change in the magnetic field strength. 相似文献
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顺磁性物质CeF3中磁化率和费尔德常数的定量计算 总被引:1,自引:0,他引:1
本文首先计及晶场对顺磁性物质CeF_3中Ce~(3+)离子4f基态和5d激发态能级的影响,进而考虑了间接交换作用有效场II_v和外磁场H_e共同作用下导致的晶场基态能级的进一步分裂,然后应用基态双能级跃迁模型定量计算了CeF_3中的比法拉第旋转θ_F,费尔德常数F和磁化率X以及它们与温度的依赖关系.计算表明,CeF_3中的磁光效应及其温度特性与Ce~(3+)离子之间的间接交换作用密切相关,在60相似文献
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为了获得飞秒激光与固体靶相互作用中自生磁场的大小与空间分布情况, 利用光学多道分析(OMA)谱仪(谱分辨0.1nm )加电荷耦合器件(CCD)相机(11521242)探测设备, 用消色差的相机镜头作为空间分辨,在固体靶前表面测量了激光的高次谐波(n0)光谱, 观测到了n0光谱的精细结构及其频率间隔,由此推出激光与固体靶相互作用中产生的等离子体内的自生磁场达60-70特斯拉(T)量级, 且越接近靶法线方向磁场越强,其一维空间分布为环形。 这一结果为进一步研究强场物理中自生磁场的特性及等离子体的整体行为提供了依据。 相似文献
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采用光学传输矩阵方法,研究了外磁场作用下一维光子晶体的光传输特性.在外磁场作用下,介质介电函数在回旋频率ω.附近受到强烈的调制,使组分材料的色散关系发生明显改变,导致光子晶体的能带发生变化,透射谱出现复杂结构.在光子带隙中出现窄通带,窄带中的光是局域的.这表明,在不改变光子晶体组分材料的条件下,可以通过改变外磁场的大小,调制光子晶体的能带及其光传输性质. 相似文献