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We propose a structure that uses surface plasmon resonance (SPR) of two-dimensional (2D) materials to enhance the sensitivity of the biosensor. When the GH shift is used as an interrogation to the biosensor, since SPR can greatly enhance and control the Goos-Hanchen (GH) shift, the biosensor will have excellent sensitivity. Theoretical research results show that by adjusting the structural parameters, a huge GH shift and a sensitivity that is hundreds of times higher than that of ordinary biosensors can be obtained. This will help research in areas such as basic biology and environmental monitoring.

In this paper, a bimetallic sensor based on graphene-hexagonal boron nitride (hBN) heterostructure is theoretically studied. The sensitivity of the sensor can be improved by enhancing the Goos–Hänchen (GH) shift in the infrared band. The theoretical results show that adjusting the Fermi level, the number of graphene layers and the thickness of hBN, a GH shift of 182.09 λ can be obtained. Moreover, sensitivity of 2.02 × 105&nbsp, λ/RIU can be achieved with monolayer graphene, the thickness of gold layer is 20 nm, silver layer is 15 nm, and the hBN thickness of 492 nm. This heterogeneous infrared sensor has the advantages of high sensitivity and strong stability. The research results will provide a theoretical basis for the design of a new high-sensitivity infrared band sensor.

With more attention to sustainable development, renewable energy generation is widely used in the region with abundant solar energy and wind energy. However, they also bring security problems to power network quality. In order to improve the power quality and ensure the stability of renewable energy generation, this paper proposes an automatical parameter droop control (APDC) method that automatically adjusts parameters. This control algorithm combines the improved virtual resistance capacitor control with the improved droop control. Firstly, a typical renewable energy microgrid model is proposed. Secondly, a power differential term and a DC bus voltage correction term are added for inverter droop control. Finally, the output power of energy storage units is timely adjusted according to the change of the state of charge (SoC). The simulation results show that the control method has faster response than traditional droop control and increases stability of DC grid.

The blade deformation caused by aerodynamic and centrifugal loads during operating makes blade configurations different from their stationary shape. Based on the load incremental approach, a novel pre-deformation method for cold blade shape is provided in order to compensate blade deformation under running. Effect of nonlinear blade stiffness is considered by updating stiffness matrix in response to the variation of blade configuration when calculating deformations. The pre-deformation procedure is iterated till a converged cold blade shape is obtained. The proposed pre-deformation method is applied to a transonic compressor rotor. Effect of load conditions on blade pre-deformation is also analyzed. The results show that the pre-deformation method is easy to implement with fast convergence speed. Neither the aerodynamic load nor centrifugal load can be neglected in blade pre-deformation.

Shrimp that touch each other can be slightly misleading in assessing shrimp quality using a machine vision system. To address this problem, a recognition-based segmentation technique called improved pruning method based watershed algorithm is presented. 352 individual shrimp was used to construct the classification model in the training stage, average hit ratio of 96.39% and average standard deviation of 0.0265 were achieved with three repetitions. In the testing stage, 247 touching shrimp were tested using the proposed algorithm under six touching scenarios. Results indicate that the proposed algorithm can successfully separate the touching shrimp with average hit ratio of 90.94% and average standard deviation of 0.065 on touching shrimp dataset with three repetitions. This outcome demonstrates that the proposed algorithm is effective and appears to be sufficiently robust to separate most of the touching scenarios with a few exceptions when shrimp are overlapped or have rough boundaries.

A wheel-legged rescue robot design with strong environmental adaptability is proposed. The design presented is aimed at helping rescue workers complete their missions, such as environmental and personnel search, quickly and accurately. So it has broad application prospects. In order to achieve the advantages of simple structure, easy control, small occupation space, and wide motion range, a wheel-legged rescue robot is designed in this paper, and the robot can realize three kinds of motion states, which include wheel state, rotation center lifting process, and leg state. Then the motion states are analyzed in detail, which provides a reference for motion control. Considering the wheel state and leg state share the same structure to contact with the ground, the effect of the stiffness of wheel-legged structure to the motion performance is analyzed. Then the experiment is carried out to prove the feasibility of the structure design. This study offers a design and quantitative analysis for wheel-legged rescue robot. Furthermore, a basis for future control research and engineering applications is established.

Torsional vibration of shafts is a very important problem in engineering, in particular in ship engines and aeroengines. Due to their high levels of integration and complexity, it is hard to get their accurate structural data or accurate modal data. This lack of data is unhelpful to vibration control in the form of structural modifications. Besides, many parts in shaft systems are not allowed to be modified such as rotary inertia of a pump or an engine, which is designed for achieving certain functions. This paper presents a strategy for torsional vibration control of shaft systems in the form of structural modifications based on receptances, which does not need analytical or modal models of the systems under investigation. It only needs the torsional receptances of the system, which can be obtained by testing simple auxiliary structure attached to relevant locations of the shaft system and using the finite element model (FEM) of the simple structure. An optimization problem is constructed to determine the required structural modifications, based on the actual requirements of modal frequencies and mode shapes. A numerical experiment is set up and the influence of several system parameters is analysed. Several scenarios of constraints in practice are considered. The numerical simulation results demonstrate the effectiveness of this method and its feasibility in solving torsional vibration problems in practice.

In order to effectively evaluate the impact on network situation under DDoS attacks, this paper proposes a hierarchical network threat situation assessment method based on D-S evidence theory for DDoS. It is divided into the basic data acquisition layer, the metric indexes extraction layer, the device threat assessment layer and the threat situation assessment layer. Firstly, we calculate indexes that represent degrees of host resources consumption and qualities of network from the basic running data. Next, the D-S evidence theory is used to fuse above indexes, which assesses impact on the network of each device caused by DDoS attacks. Then, on the basis of service importance principle, we calculate the weight value of each device in the network. Furthermore, the threat situation value is obtained through weighted algorithm. Finally, experimental results show that the proposed method can vividly reflect the impact of DDoS attacks on the network security threat situation.

This paper presents a study of a beam-like semi-active electromagnetic vibration absorber (EVA). The EVA consists of a flexible ferromagnetic cantilever beam, a ferromagnetic mass attached to the free end of the beam, and an E-shaped electromagnet. By changing the current of the electromagnet, the interactive force between the ferromagnetic mass and the electromagnet is varied accordingly, hence, the stiffness of this EVA is online tunable. The working frequency of the EVA is adjusted simultaneously as well. A finite element method (FEM) analysis study has been carried out to determine the characterization of the EVA. The effective stiffness of the absorber from FEM agrees with the results from the experiment well. A 2 degree-of-freedom experimental semi-active control system is built up to test the effectiveness of the EVA design. The performance under both steady-state exciting and sweeping frequency exciting show the EVA effectiveness in vibration suppression.

In this paper, the influences of fiber link and laser source on performances of Radio over Fiber (RoF) including error vector magnitude (EVM), constellation and eye diagram are investigated by simulation using Opti-system12 (trial version). The investigated RoF network is built on IEEE 802.16a WiMAX, with 16 QAM and a Mach-Zehnder modulator for intensity modulation. The mechanism of that the dispersion in fiber link makes the constellation rotate is investigated. The relationship between the rotation angle of the constellation and dispersion is analyzed, where we first put forward a fitting formula to describe this approximate quantitative relation. In the analysis of the influence of the laser source on the network, where the dispersion compensates fiber (DCF) is applied to compensate the rotation in constellation caused by fiber link, the threshold in the relationship curve of the linewidth and EVM is obtained. It is found that if the laser linewidth exceeds this threshold, the EVM will increase rapidly, then, the performance decreases.

The CXC chemokines (CXC-motif ligand 12 and CXC-motif ligand 14) and platelet-derived growth factor are suggested to modulate remyelination in the course of many demyelinating diseases. The present study compared the difference in the brain levels of these chemokines between patients with idiopathic demyelinating optic neuritis (IDON) and neuromyelitis optica (NMO) by measuring their concentrations in the cerebrospinal fluid using an enzyme linked immunosorbent assay. Our data indicate that the prognosis of neuritis depends on the remyelinating process that is impaired due to decreased chemokines. The much lower levels of chemokines would specifically indicate the severe neuritis, such as NMO.