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Petal-like ultra-evenly Rh-doped Co2Fe-P composite was fabricated by a solvothermal and in-situ phosphorization strategy. Through doping a small amount of Rh within the Co2Fe-P structure, the catalytic activities of the composite for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) could be highly improved, and an excellent electrochemical bifunctional catalyst could be achieved. Under acidic reaction conditions, it only required an overpotential of 76 mV for HER to achieve a current density of 10 mA·cm−2. Meanwhile, excellent electrochemical performance could also be obtained in alkaline electrolytes. The overpotential was 48 mV for HER and 303 mV for OER at 10 mA·cm−2 in 1 M KOH, respectively. Impressively, as a bifunctional electrode, the Rh doped Co2Fe-P composite can release a current density of 10 mA·cm−2 at a low cell voltage of 1.54 V in 1 M KOH for overall water splitting, which could be compared with that using commercial noble metal catalysts.

A series of Al-doped CoP2/rGO composites have been fabricated by in-situ precipitation and phosphorization protocol. The well-ordered arrangement and widely adjustable mole ratio of cations within Co–Al layered double hydroxide (CoAl-LDH) make it suitable as a precursor for phosphiding and generating evenly dispersed Al element within CoP2 structure. The effect of Al doping content on the catalytic activities for hydrogen evolution reaction thus could be discussed in detail. Electrocatalytic performance indicates that the doping of Al element within CoP2 structure could efficiently prevent the oxidation of phosphide on the surface, and thus resulting in the high electrocatalytic activity for hydrogen evolution reaction (HER). Among all the Al-doped CoP2/rGO materials, the composite with the Co/Al mole ratio of 2/1 presents the highest HER activity and stability whatever under acidic or basic reaction conditions, which could be comparable to the most reported HER electrocatalysts and even the commercial 20% Pt/C. At the current density of −10 ​mA ​cm−2 in 0.5 ​M ​H2SO4, the overpotential is only 59 ​mV with a Tafel slope of 73.2 ​mV dec−1. Interestingly, the Al content could be dissolved under basic media and resulting in a porous structured electrode. Only the overpotential of 60 ​mV is needed to get the current density of −10 ​mA ​cm−2 in 1 ​M KOH.

This study presents a novel planar coupled-line directional coupler with tunable both power division ratio and operating frequency, which is achieved using microstrip technology for the first time. Its tunability of the operating frequency and the power division ratio, or coupling ratio, can be independently controlled by the bias voltages. Moreover, it can simultaneously maintain perfect port match and isolation. On the basis of the even–odd mode analysis method, both the closed-form analytical equations and parameter discussions are provided to facilitate the practical design. An experimental prototype of the tunable coupler is simulated, fabricated, and measured to demonstrate how it works. The measured results indicate that power division ratio can vary from 0.35 (9 dB) to 0.71 (3 dB) when operating frequency ranges from 0.55 to 1.48 GHz (91.63%) while power division ratio varies from 0.35 (9 dB) to 1 (0 dB) when operating frequency is fixed at 1 GHz, which validated the reliability of the proposed model.

In this paper, a novel coupled-line tunable Wilkinson power divider with perfect port match and isolation in a continuously tunable passband is presented. The proposed tunable power divider consists of an isolation resistor, two coupled lines, and two types of varactors. By providing these varactors with suitable bias voltages, the operating frequency of the proposed power divider can be flexibly changed as desired. Meanwhile, perfect port match and isolation are maintained at all tunable operating frequencies. After applying the even-odd mode analysis method, the closed-form equations of the design parameters are derived to illuminate the effects on the minimum and maximum operating frequencies. These equations exhibit that the proposed power divider has a wide frequency tuning range and a high tunability (more than 110% in ideal conditions). Owing to the limitation of manufacturing process, a microstrip power divider with a tunable frequency of 0.54–1.41 GHz (89.23%) is designed and simulated based on the provided closed-form equations. The measured results show a frequency tuning range from 0.56 to 1.39 GHz (85.13%) with a more than 20-dB return loss and isolation in the entire tuning range, agreeing well with the simulation results.

Steerable properties dominate the design of traditional filters, e.g., Gabor filters, and endow features the capability of dealing with spatial transformations. However, such excellent properties have not been well explored in the popular deep convolutional neural networks (DCNNs). In this paper, we propose a new deep model, termed Gabor Convolutional Networks (GCNs or Gabor CNNs), which incorporates Gabor filters into DCNNs to enhance the resistance of deep learned features to the orientation and scale changes. By only manipulating the basic element of DCNNs based on Gabor filters, i.e., the convolution operator, GCNs can be easily implemented and are compatible with any popular deep learning architecture. Experimental results demonstrate the super capability of our algorithm in recognizing objects, where the scale and rotation changes occur frequently. The proposed GCNs have much fewer learnable network parameters, and thus is easier to train with an endtoend pipeline. The source code will be here 1.

A novel dual-band Butler matrix is proposed with the same phase difference, aiming at the interest of long-term evolution. The total circuit simply includes four 3-dB 90° dual-band couplers and two 45° broadband phase shifters, which are capable of operating at two separate frequencies. Due to the utilized 45° broadband phase shifter, the phase differences remain invariant at two unrelated frequencies between the adjacent outputs. This Butler matrix can be easily fabricated by using single-layer microstrip technology. The measured results of a prototype demonstrate that it can operate at both 1.85 and 2.7 GHz, which perform phase errors and coupling ratios within 5.44° and –6.63 ± 0.72 dB.

In this paper, a novel compact tunable coupled-line power divider using varactors is presented. It has a compact circuit due to the coupled line with short electrical length. The operating frequency can be flexibly controlled by the bias voltage because the capacitance of the varactors is regulated by the applied bias voltage. The theory of this power divider is analyzed and a microstrip example of this tunable power divider is designed, fabricated, and measured. The measured results indicate that the operating frequency of the proposed tunable power divider ranges from 0.8 to 1.15 GHz, agreeing well with the simulated result.

All-optical XOR gates for QPSK signal based optical network applications such as checksum, error recognisation etc., aided by a partially-modulated QPSK signal, are demonstrated through a 10-Gbaud proof-of-concept experiment with power penalty of 4 dB.

As an important means to sense the environment for robot, laser scanner has high accuracy, relatively simple data processing and large measurement range, compared with other sensors. The application of laser in robot is mainly used in obstacle avoidance, environment modeling and mapping. In this paper, the application of laser scanner in obstacle avoidance, automatic recharge and target tracking, is introduced through a laser-vision based robot navigation system. And the feasibility of application is verified through experiments.