只有在没有反射或反射因素极小的情况下，在发射端和接收端电磁场的时间差可以用于计算电磁场从反射端到接收端的传播相速度。由于反射，测量到的合成波的相位是入射波和反射波相位的合成，由反射而引入的相位变化导致发射和接收端之间的同相位电磁波的时间差的移动。这种两点间的合成波的时间差由于反射既能增加也可能减小，在一定的情况下，时间差还可以是负数。由于忽视因反射而引起的相位差或时间差的变化，最近发表在《现代物理》上的两篇文章的作者们用带有反射的合成波的时间差计算电场传播速度，并和光在自由空间里传播相速度比较，进而在两篇文章中错误地宣称：“交变电场的速度超过光速20倍以上。”这两篇在《现代物理》上发表的文章是：“导线中交流电场时间延迟的测定”(现代物理，2015，5，29-34)和“交变电场速度测量的物理原理”(现代物理，2015，5，35-39)。此评论文章用理论和实验数据推翻其文章“超光速20倍”的结论。
The time shift of an electromagnetic wave at a single frequency between a transmitter and a re-ceiver can be used to determine the phase velocity of the wave propagation only if there is no reflection at the receiver or the reflection is very small. The reflection adds additional phase shifts to the composted wave of an incident wave and a reflected wave so that the time difference of the composted wave is shifted between the transmitter and the receiver. This time difference may be either decreased or increased and even negative in a certain condition. Ignoring the phase shift and time shift induced by the reflection, the authors of two articles recently published on “Modern Physics” wrongly claim of “the speed of alternating electric field can be 20 times faster than the speed of light”. The two articles are: “Measurement of Time Delay of Alternating Electrical Field in Wires” (Modern Physics, 2015, 5, 29-34) and “Physical Principles of Measuring the Speed of Alternating Electrical Field” (Modern Physics, 2015, 5, 35-39). In this communication note, theory and experiments are presented to falsify their claim.

交流电源产生的电动势在电路内产生了电势差以及交变纵向电场。交变电场在金属导线内的速度不是常数，它与电路参数相关。在大多数情况下，交变电场的速度是低于光速的。可是，在特定的电路参数情况下，交变电场的速度超过光速20倍以上。本文分析了RL电路中交变电场的时间延迟问题，并且推导出了导线中交变电场的速度公式。 AC electromotive force generates alternating potential differences and longitudinal electric fields in a circuit. The speed of alternating electric field within the metal wire is not constant, which is related to the circuit parameters. In most cases, the speed of alternating electric field is lower than the speed of light. However, under certain circuit parameters, the speed of alternating electric field can be 20 times more than the speed of light. This paper analyzes the time delay of the alternating electric field in RL circuits. The formula of the speed of alternating electric field in a wire is deduced.

交流电源产生的电动势在电路内产生了交变电势差以及纵向电场。交变电场在金属导线内带动了电子运动，产生了电流和电功率。交流电(功率)的速度不是常数，它与电路参数相关。在大多数情况下，交流电的速度是低于光速的。可是在特定的电路参数情况下，交流电的速度可能超过光速20倍以上。我们实验的出发点是RL交流电路的电压方程,其中包含了欧姆定律。这个方程是与Maxwell方程相互独立的。本实验的关键是：RL电路中纵向交变电场的时间延迟是由直导线自身的电感是引起的，导线自感量与长度有一定的相关性。实验表明，交流电在金属导线中可能以超光速传输信号和电能。光速不是一切物质运动的极限。
Alternating electromotive force generates alternating electrical potential difference and produces a longitudinal electric field in circuits. An alternating electric field within the metal wire leads the movement of electrons, resulting in a current and electric power. The speed of alternating elec-tricity is not constant, which is associated with the circuit parameters. In most cases, the speed of alternating electricity is less than the speed of light. However, under some specific circuit para-meters, the speed of alternating electricity may exceed more than 20 times the speed of light. The voltage equation of RL circuit involves the Ohm’s law. This equation is independent of Maxwell equations. The key in our experiment is: in RL circuits, the time delay of alternating electric field is caused by the wire inductance, which is related to the length of the wire. Our experimental results show that the speed of alternating electricity may be 20 times faster than the speed of light. The speed of light is not the up-limit in universe.

交流电源产生的电动势在电路的金属导线内产生了电势差以及纵向电场。纵向电场驱动了电子，形成了电流。纵向电场是非局域的。由于金属导线自身分布电感的存在，产生了时间延迟。这篇论文给出了电路中低频交流电场的时间延迟的初步测量结果。实验结果表明，在小于3 MHz的频率区，纵向电场的速度超过光速20倍以上。 AC electromotive force generates a potential difference and a longitudinal electric field in a circuit. The longitudinal electric field drives the electrons, and forms a current. Longitudinal electric field is non-localized. Due to the distributed self-inductance of the metal wire, it generates a time delay. This paper gives the results of preliminary measurements of time delay of low-frequency AC electric field. Experimental results show that, in less than 3 MHz frequency region, the speed of longitudinal electric field is more than 20 times of the speed of light.

Abstract:
Based on transformation-optical approach, the distribution of permittivity and permeability for the N-sided regular polygonal electromagnetic wave concentrator is derived and functionality of the concentrator is numerically confirmed by the finite element solver COMSOL. Electric field and total energy distributions in the vicinity of the three-, four-, five- and six-sided regular polygonal concentrators are simulated. The influence of the focus area and deviation of material parameters from perfect N-sided regular polygonal concentrator on the concentrating effect is studied. The results show that the smaller the focus area, the stronger the total energy density; The deviation of material parameters from perfect concentrator results in a distortion of the electrical field and total energy density distribution.

Abstract:
The movement and radiation of fast electrons emitting along the surface of a target irradiated by intense laser pulses has been investigated theoretically and numerically by use of the classical theory of Thomson scattering by free electrons in static field. The results indicate that the surface electrons are oscillating in the quasistatic field and the laser field at the beginning. The electrons will be accelerated when their oscillation frequency comes close to the laser frequency, and the attosecond pulse trains and high harmonic are emitted along the surface by surface electrons. The temporal and spatial characteristics of the acceleration and radiation of electrons in different initial states has been compared. The frequency characteristic of the coherent radiation of electron beams are also investigated.

Abstract:
A quasi-direct solution (QDS) for the finite difference equations has been developed, which is basel on the sparse and pivot-dominant properties of the matrix and is the combination of the direct method and the iterative method. The principle and the features of QDS method have been discussed. A comparison has been made with the successive over-relaxation (SOR) method. It is shown that the QDS method requires less computer memory than the direct method, covnerges faster than the SOR method and is suitable for calculating the finite difference equations of electromagnetic and magnetostadc problems.

Abstract:
中医之气分类繁多，基于全同性的概念通过分析各类气的基本属性、功能特点及现代化研究，发现各类中医之气具有不可分辨性，推断出中医之气具有全同性。对明晰中医气的概念、完善中医理论体系、促进中医学的发展和指导临床实践具有一定的指导意义。 There are many kinds of categories of Qi in traditional Chinese medicine (TCM). Based on the concept of identity principle, by analyzing the basic attributes, functional characteristics and modern researches of various categories of Qi, we have the presumption that Qi of TCM has identity principle. This provides a theoretical significance for clarifying the concept of Chinese medicine Qi, perfecting the theoretical system of TCM, promoting the development of TCM and guiding clinical practice.

Abstract:
The difficulties that exist in classical electromagnetic field theory are discussed and it is pointed out that the Maxwell's equation set in classical theory is not self-consistent and only the approximate solutions can be gotten in classical electromagnetic theory. And how to establish the modern electromagnetic field theory based on modern mathematics and concepts of modern physics is given for solving this problem. By the modern electromagnetic theory, the mathematical form for macroscopic electromagnetic field theory is obtained and the exact solutions for electromagnetic field boundary value problem can be gotten.