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For the stabilization problem of underactuated RTAC (Rotational/Translational ACtuator), a sliding mode control (SMC) strategy is designed and presented based on neural network and active disturbance compensation. To overcome the underactuated characteristics, a new "actuated" state is constructed as an output by combining the underactuated and actuated states to transform the underactuated model to an actuated form, and the linear extended state observer (LESO) is employed for the total disturbance of the proposed model. By applying the neural network to approximate the optimal control outputs, the proposed method can achieve satisfactory control performance without a precise dynamic model. Furthermore, The stability analysis of the RTAC is presented based on rigorous Lyapunov method. The simulations are provided to validate the method. The simulations with the existing method are also provided as a comparison.

This paper presents a 40-75 GHz balanced vector modulator using a 0.15μm GaAs pHEMT technology for quadrature phase shift keying modulation. In order to enhance operation bandwidth, balanced vector modulator with a compact broadside coupler is proposed. To miniaturize the parasitic effects, a balanced or a push-pull topology is adopted, where two bi-phase amplitude modulators with 180° phase difference are co-designed to realize the bi-phase function. Thus, the influence of parasitic parameters is canceled out due to the out of phase signal combination. The designed prototype has simulated results of a 35 GHz operation bandwidth centered at 58 GHz, the amplitude and phase errors within ±1 dB and ±3°, insertion loss of less than 14 dB and input return loss is better than 11 dB.

Mannitol, an important raw material in food industry and medical fields, is always expected to be produced by the method of biotransformation. It was found in our previous work that Lactobacillus buchneri CGMCC 7300, isolated from traditional fermented sauerkraut, showed the ability of high-producing mannitol. In this study, the production methods of mannitol by L. buchneri CGMCC 7300 with one-step or two-step transformation strategy were optimized using the mixture of fructose and glucose as the substrate. One-step method involved the cell growth and mannitol production in a single process. The result indicated the mixture of fructose and glucose with a total concentration of 90 g/L and ratio of 3:2 was the optimal substrate to produce mannitol, reaching a yield of mannitol 48.82 g/L. On this basis, a two-step transformation strategy was tried and optimized to produce mannitol. In this method, the cells were firstly cultured, then collected and added into the 3 substrate for biotransformation. The optimal transformation conditions were found as follows: the total concentration of the fructose and glucose mixture 120 g/L, transformation time 36 h at 32 °C, medium pH 5.0. Under the above conditions, mannitol’s yield reached 63.71 g/L, 30.5% more than the yield of the one-step transformation method, showing that the two-step transformation method had a great advantage in mannitol production. The results will be significant for further industrial-scale production of mannitol.

This paper presents a 6-way power combining amplifier based on a 3-way traveling-wave waveguide combiner and waveguide-microstrip double probes. According to the reactive measure results, the input and output return loss (RL) of the 6-way dividing/combining networks are more than 17dB from ×3.5 GHz to ×5.5 GHz.The insert loss (IL) of the back-to-back is about 1.5dB, the combining loss is about 0.65dB.The saturated power (Psat) of the power amplifie (PA) is more than 9W, the combining efficiency is about 80%.