Compact Antenna with Enhanced Performances Using Artificial Meta-Surfaces

In recent years, artificial meta‐surfaces, with the advantages of smaller physical space and less losses compared with three‐dimensional (3D) metamaterials (MTM), have intrigued a great impetus and been applied widely to cloaks, subwavelength planar lenses, holograms, etc. Typically, one most important part for meta‐surfaces’ applications is to improve the performance of antennas. In this chapter, we discuss our effort in exploring novel mechanisms of enhancing the antenna bandwidth using the magneto‐electro‐dielectric waveguided meta‐surface (MED‐WG‐MS), achieving circular polarization radiation through fractal meta‐surface, and also realizing beam manipulation using cascaded resonator layers, which is demonstrated from aspects of theoretical analysis, numerical calculation, and experimental measurement. The numerical and measured results coincide well with each other. Note that all designed antenna and microwave devices based on compact meta‐surfaces show advantages compared with the conventional cases

A MPPT Method based on Improved Fibonacci Search Photovoltaic Array

The P-U curve of photovoltaic arrays (PVAs) has multi-peak characteristics under uneven illumination environments, and the maximum power point tracking (MPPT) strategy for the single peak may fail. An improved Fibonacci search algorithm is proposed to carry out MPPT of photovoltaic arrays under uniform illumination or light mutation. A multiple-interval search algorithm based on a circuit analysis method is presented for different topology arrays and illumination distributions. The series array analysis adopts the current analysis method, the parallel array analysis adopts the voltage analysis method, and the series and parallel array analysis adopts the current and voltage analysis method; then, the output control volume is determined, and the search interval is divided. The search steps in the Fibonacci method and the real-time changes of parameters in the optimization process can be observed by MATLAB simulation. Experimental results show that the algorithm uses less computation time and small area search instead of global search

Oxygen uptake rate (OUR) control strategy for improving avermectin B1a production during fed-batch fermentation on industrial scale (150 m3)

Glucose metabolism plays a crucial role in the process of avermectin B1a biosynthesis. Controlling glucose feeding based on oxygen uptake rate (OUR) was established to improve the efficiency of avermectin B1a  production. The result showed that avermectin B1a production was greatly enhanced by OUR control strategy. In the glucose feeding phase, OUR was maintained at approximate 12 mmol/L/h, which was conducive to avermectin B1a biosynthesis. Using this OUR control strategy, an adequate supply of organic acid precursors produced avermectin B1a 5228 U/mL, which was 22.8% higher than that of the control (batch fermentation, 4256 U/mL) on industrial scale.Key words: Avermectin B1a, glucose feeding, oxygen uptake rate, industrial scale

Randomized, Double-Blind, and Placebo-Controlled Trial of Clenbuterol in Denervated Muscle Atrophy

Objectives. β2-adrenergic agonists, such as clenbuterol, have been shown to promote the hypertrophy of healthy skeletal muscles and to ameliorate muscle wasting in a few pathological conditions in both animals and humans. We intended to investigate the clinical efficacy of clenbuterol on attenuating denervation-induced muscle atrophy. Methods. A double-blind, placebo-controlled, parallel, and randomized trial was employed. 71 patients, suffering from brachial plexus injuries, were given either clenbuterol (60 μg, bid) or placebo for 3 months. Before and at the end of the study, patients were given physical examinations, biopsies of biceps brachii, electromyograms (EMGs), and other laboratory tests. Results. Compared with placebo treatment, clenbuterol significantly mitigated the decreases in cross-sectional areas of type I and II muscle fibers and alleviated the reduction in fibrillation potential amplitudes, without any adverse effects. Conclusions. Clenbuterol safely ameliorated denervated muscle atrophy in this cohort; thus larger clinical studies are encouraged for this or other β2 agonists on denervation-induced muscle atrophy