Based on the transfer matrix method, the recursion of an electromagnetic wave propagating in an asymmetric Kerr nonlinear medium is analytically formulated, from which the rectification effect is clearly presented. The effects on the rectification region of the linear part and nonlinear coefficient of permittivity are both studied, and the energy densities before and after rectification are discussed. We use a rectifying factor to describe the intensity of the rectification effect.The result shows that every transmission peak is divided into two parts when the symmetry is broken, and nonlinear asymmetry has a more significant effect on the rectification effect than the linear asymmetry. The rectification intensity and area will be enlarged when the asymmetry factor is increased in a certain range.
在射频识别(Radio Frequency IDentification,RFID)系统中,传输信号在高速远距离传输过程中,受传输环境和突发状况等影响,导致传输信号产生畸变和衰减,解调后的基带信号会产生码间干扰,影响了信号传输质量,并且限制了传输的速度。文中提出了一种适用于RFID系统基带数据传输的自适应FFE-DFE均衡的方法。该方法实现复杂度低,不需要很复杂的电路设计,算法计算速度快。实验结果表明,自适应FFE-DFE均衡方法有效改善了均衡效果,减小了误码率,消除了信号中的码间干扰和噪声,数据传输距离大大延长。
We have performed density-functional calculations of the transport properties of the zigzag graphene nanoribbon(ZGNR) adsorbed with a single iron atom. Two adsorption configurations are considered, i.e., iron adsorbed on the edge and on the interior of the nanoribbon. The results show that the transport features of the two configurations are similar.However, the transport properties are modified due to the scattering effects induced by coupling of the ZGNR band states to the localized 3d-orbital state of the iron atom. More importantly, one can find that several dips appear in the transmission curve, which is closely related to the above mentioned coupling. We expect that our results will have potential applications in graphene-based spintronic devices.
Tantalum-doped TiO_(2) films were deposited on glass at 300℃ by pulsed laser deposition(PLD).After postannealing in vacuum(∼10^(−4) Pa)at temperatures ranging from 450℃ to 650℃,these films were crystallized into an anatase TiO_(2) structure and presented good conductive features.With increasing annealing temperature up to 550℃,the resistivity of the films was measured to be around 8.7×10^(−4)Ω・cm.Such films exhibit high transparency of over 80%in the visible light region.These results indicate that tantalum-doped anatase TiO_(2) films have a great potential as transparent conducting oxides.
