共查询到20条相似文献,搜索用时 78 毫秒
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在考虑平面型摆动器(Wiggler)场误差△B(z)的情况下,求解电子在磁场中运动的洛仑兹(Lotentz)方程,得到场误差对电子横向速度的改变,然后作傅里叶变换即为电子自发辐射谱的改变,并讨论了各种场误差对自由电子激光器自发辐射谱的影响,选择北京自由电子激光器(BFEL)参数,进行模拟,最后确定出各种场误差的可接受条件。 相似文献
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测量了有机超导体κ(BEDTTTF)2Cu(SCN)2单晶的X射线衍射和强磁场下磁阻.样品沿垂直于传导面的晶格常数为1.49nm.在1.2K温度,磁场垂直于传导面的位形下,在6T以上观测到磁阻振荡,即ShubnikovdeHas效应.由FFT(FastFouierTransformation)谱图,我们发现了对应于κ(BEDTTTF)2Cu(SCN)2单晶Fermi面闭合轨道Fα频率和开放轨道磁突破频率Fβ的存在,Fα=620±30T,Fβ=4100±200T. 相似文献
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Denisov A. P. Bryzgunov M. I. Ivanov A. V. Parkhomchuk V. V. Putmakov A. A. Reva V. B. 《Physics of Particles and Nuclei Letters》2019,16(6):876-884
Physics of Particles and Nuclei Letters - One way to increase the efficiency of electron cooling is to increase the electron density in the beam reference frame. As a rule, with an increase in the... 相似文献
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Leif Henriksen 《辐射效应与固体损伤》2013,168(1)
T. B. Rymer Methuen, London; Barnes and Noble, New York, 165 pages, 7 plates. £2.50 相似文献
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The arguments leading to the concept of an electron crystal in the low density regime of ‘jellium’ are reviewed. Ground-state properties discussed include estimates of the critical density at which the transition to a crystalline state takes place, and then in the low density regime the dielectric function, pair function and momentum distribution are dealt with. The magnetic character of the ground state as a function of density is also considered. The low-lying excitations of the Wigner electron crystal are phonon-like and hence the low temperature specific heat obeys a T 3 law. Defect models are considered in order to throw further light on the character of excited states. Finally experimental conditions favourable for electron crystallization are briefly considered. 相似文献
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Ballistic electron waveguides are open quantum systems that can be formed at very low temperatures at a GaAs/AlGaAs interface. Dissipation due to electron–phonon and electron–electron interactions in these systems is negligible. Although the electrons only interact with the walls of the waveguide, they can have a complicated spectrum including both positive energy bound states and quasibound states which appear as complex energy poles of the scattering S-matrix or energy Green's function. The quasibound states can give rise to zeros in the waveguide conductance as the energy of the electrons is varied. The width of the conduction zeros is determined by the lifetimes of the quasibound states. The complex energy spectrum associated with the quasibound states also governs the survival probability of electrons placed in the waveguide cavities. 相似文献
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We present experimental conditions that lead to high-quality Cu2+-based double electron electron resonance (DEER) data. Such experiments are feasible at temperature of about 20 K, and sample
concentrations in the range of 0.15–1.5 mM. By systematically investigating the effects of pulse lengths, we find that observer
π pulse lengths of 20–48 ns provide reasonable modulation depths as well as signals. The length of the pump pulse needs to
be minimized (16 ns in our case). For a Cu2+–Cu2+ DEER measurement, the optimal frequency offset is about 100 MHz. For a Cu2+–nitroxide DEER measurement, the frequency offset is often varied in the range of 100–500 MHz, to probe orientational selectivity.
For both cases, the frequency of the pump pulse should be smaller than the observer pulse in order to obtain a larger modulation
depth. 相似文献
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采用法国的MAFIA程序计算电场.编制了TRAJ程序,用逐点跟踪计算电子轨迹,得到了束流包络.观察了在高压电场中栅压对束流光学传输的影响,并获得了在不同能量范围内的栅压聚焦作用,为栅压调节提供了理论依据,也为将来对其它规格的电子帘加速器的物理设计积累了十分宝贵的经验. 相似文献
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We here investigate the density and temperature dependence of polarization using the relativistic formalism for the electron–electron
interaction within the Fermi liquid model. The variational method has been used: the free energy has been minimized with respect
to the effective mass and the polarization parameter. Then we obtained the equation of state and magnetic susceptibility of
the system. The exact results for polarization and magnetic susceptibility have been obtained at zero temperature. It has
been shown that for a given temperature (density) there is a critical density (temperature) at which the ferromagnetic phase
can appear in an electron gas. The results are in agreement with previous work. Our results show that at nonzero temperatures
and in very low and very high densities the ferromagnetism phase cannot exist. 相似文献