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A compact wideband omnidirectional antenna that can cover frequency range from 0.8 GHz to 4.0 GHz is proposed in this paper, which can be adapted to 2G, 3G, 4G and 5G frequency bands. The proposed antenna is designed according to dipole structure but having excitation at one edge of the antenna via a tapering feeding line. Moreover, the antenna is purposely placed on a ABS shell to evaluate its radiation performance in practical application environment.

In this paper, a shared-radiator dual-polarized wideband antenna for 5G applications is proposed. It consists of a shared-radiator and a ground plane together with two orthogonal feeding plates. The feeding structure is formed by a microstrip power divider and a coupling slot opened on the ground to perform as a balun. The operating frequency range of the proposed antenna is 3.2 GHz to 3.7 GHz. Simulation results show that the antenna reaches reflection coefficient < -10 dB in the operating frequency band with and port isolation better than 30 dB. The antenna not only possesses good electromagnetic properties in terms of high gain, wide bandwidth, but also has simple physical structure for potential production, which makes the antenna proposed in this paper to be suitable for 5G applications.

Taking the technical and tactical performance of the world’s top female table tennis player Liu Shiwen as the research object, this study detects Liu Shiwen’s offensive performance characteristics from the perspective of the duration of preparing for the 2020 Tokyo Olympic Games. Using professional high-speed camera system software to analyze her offensive movement structure, combined with table tennis technical and tactical analysis software, this study detects and analyzes Liu Shiwen’s offensive performance in a series of contests against the world’s top female table tennis players. By integrating the offensive technical and tactical effect data, this study comprehensively describes the offensive application process in the actual combat of the team so as to improve the availability of data analysis. Different from the traditional method of video observation combined with artificial statistics, this study analyzes the techniques and tactics adopted by Liu Shiwen when she was playing against left-handed and right-handed players, as well as the advantages and disadvantages of these techniques and tactics. In doing so, the study aims to provides detailed detection information of technical and tactical performance for coaches and players, make a dynamic study of the offensive characteristics of the world’s top female table tennis players, and provide technical support for the preparation of Chinese female table tennis players for the 2020 Tokyo Olympic Games.

In order to estimate the state-of-charge (SoC) for all cells in the battery pack, this paper proposed an average cell model to represent every cell in the pack. The average cell model consisted of a basic model and a bias function. First, the parameter identification of the basic model was conducted, and the inconsistencies between cells were calibrated by the uncertainties of the basic model parameters. Second, artificial neural networks were used to construct the response surface approximate model of the bias function. In order to make the average cell model more adaptable to different working conditions, a novel bias function considering the polarization voltage and the temperature was proposed to correct the basic model, and it was compared with other bias functions. Then, the extended Kalman filtering algorithm was used for SoC estimation based on the corrected model. Finally, a case study with six lithium-ion battery cells was performed for the verification and evaluation of the proposed method. The results indicated that the average model corrected by the proposed bias function showed good adaptability to different working conditions, and the maximum absolute SoC estimate errors of all cells in the battery pack were less than 2% at 25°C, and 3.5%at 10 °C or 40 °C.

This paper deals with the model reduction methods for very flexible aircraft (VFA). Such aircraft is characterized by strong coupling between rigid motion and flexible motion, resulting in a very high order system for controll design. Recently released high-fidelity Vulture model of 707 order is chosen to be a typical example of VFA and is regarded as the reference model. Then three model reduction methods: balanced truncation method, balanced residual method and optimal hankel norm approximation are presented. Finally, numerical simulation is used to illustrate the characteristic of VFA and determine the best method for model reduction of VFA. In addition, the relationship between model error and model order is given. Both frequency domain and time domain analysis verify the reduced model of order 80 using balanced singular perturbation method is sufficient to maintain the accuracy of the full model.

Crohn's disease is a chronic autoimmune disease of the intestinal tract affecting 700,000 people in the United States. The pathology of Crohn's disease is characterized by obstructing intestinal strictures due to inflammation, fibrosis, or a combination of both. The identification of fibrosis in intestinal strictures is critical, as the fibrotic strictures are irreversible and have to be removed surgically. Fibrotic strictures are characterized by the increased collagen content in the submucosa below the inner surface of the intestine. The standard diagnostic procedure for the strictures is the endoscopic biopsy, which has limited diagnostic accuracy due to the superficial sampling. Conventional imaging modalities can identify intestinal strictures but cannot assess the molecular components within the strictures. In our previous studies, photoacoustic imaging (PAI) has demonstrated the capability to identify fibrosis in intestinal strictures by increased collagen content. The objective of this research is to further investigate the feasibility of identifying fibrosis in intestinal strictures using PAI in vivo.