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As a core equipment in power system, power transformer plays a vital role in the stability of the power grid. It is necessary to quickly and accurately monitor the fault of the transformer. Frequency response method is an important method for fault diagnosis of transformers. It has many advantages, such as simple and light test equipment, easy measurement and high test sensitivity, intuitive analysis of experimental maps, and comparability of data magnitude analysis. It is considered to be a detection method with good application prospects. In this paper, the monitoring principle of frequency response method and the influencing factors in practical application are analyzed, and the shortcomings of the method and the research direction of the next step are prospected.

Beam wander effects have been discussed as the main reason for the failure of the first-order Rytov approximation to properly predict the scintillation index of Gaussian beam through the atmospheric turbulent channel of optical wireless communication. This paper investigates the beam wander effects on scintillation theory of Gaussian beam based on the new generalized anisotropic non-Kolmogorov power spectrum, where all the influence of the anisotropy of turbulence, the general spectral power law, and the finite turbulence inner and outer scales are considered simultaneously. For both horizontal path and uplink path, novel expressions of the beam wander, the wander-induced pointing error variance and the beam-wander-induced scintillation index are derived. Numerical simulations are performed to show the significant influence of beam wander on the scintillation index in the propagation of Gaussian beam.

The human lower extremity exoskeleton (HLEE) conceived and designed to provide human the ability to carry heavy loads on his back with minimal effort over type of rugged terrain, which integrated human-robotic system under the control of the human. Based on bionics, HLEE structure was analyzed and designed. Mathematical models of human typical gait were built. The Virtual prototype of the human and the Lower Extremity Exoskeleton were produced using Pro/e three-dimensional modeling software and ADAMS kinematic modeling package. Trajectory of human motion was programmed using the cubic spline interpolation. The accuracy and the assumptions feasibility of the model were proven by simulation.