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We use two-dimensional Fourier transform spectroscopy to measure coherence between the trions in the opposite valleys in monolayer MoSe2. The trion valley coherence time ∼230fs is limited by pure dephasing of the trion resonance.
Recent work in terrain recognition for outdoor mobile robots mainly focused on several typical pure terrain sample classification, and only one terrain feature is extracted for terrain sample description. In this paper, a segmentation scheme for complex terrain samples is designed for the terrain recognition process. The segmentation scheme is achieved using the graph segmentation followed by the...
The frequency selective surface (FSS) with ultra-wide passband performance and a sharp rejection near the side of the passband is investigated in this paper. The proposed cascaded FSS consists of a 2-D periodic array of square loop aperture (SLA) and an array of bandstop square loop (SL) with different period. Under different incident waves, the proposed second-order FSS and third-order FSS provide...
Research results in neurophysiology show the predictive nature of vergence eye movement, vergence eye movement can persistently track a moving target which shifts in distance relative to the head. Few models have attempted to consider prediction of target motion in vergence models. Most models only considered static targets, their input are frozen driving signals. In this paper, a model with estimator...
This article intends to provide an overview of the state of art in developmental models of cognitive robots. With the development of artificial intelligence, robots have been able to perform a variety of complex tasks controlled by human. However, it is still a challenge for robots that they can explore and develop their cognitive ability in the specific environment like human beings. The current...
Human action recognition has attracted much attentions because of its great potential applications. With the rapid development of computer performance and Internet, the methods of human action recognition based on deep learning become mainstream and develop at a breathless pace. This paper will give a novel reasonable taxonomy and a review of deep learning human action recognition methods based on...
In this study, quadrotor vertical taking off and landing (VTOL) control problem of a quadrotor is investigated. A control strategy which has an inner-outer loop structure is proposed. A backstepping based controller is designed for the outer loop to fulfill position tracking aim. The inner loop is regarded as a nominal system with lumped disturbances which contains parameter perturbations, external...
Boiler drum system plays a crucial role in the process of chemical industry. It is a complicated dynamic system with both unknown external disturbances and time varying parameters in model. Due to the external and internal disturbances in the process, it is hard to keep system totally stable in the real operating condition. In this paper, time varying parameters in model are identified and the internal...
The design, fabrication and testing of a novel resonant accelerometer integrated with a temperature sensor is presented in this paper. The accelerometer consists of double quartz resonators and a silicon substrate. A novel diamond like carbon (DLC) film with special electrical property, excellent mechanical property and chemical stability, which has negative temperature coefficient of resistance (TCR),...
In this paper, a model independent PD with sliding mode control (PD-SMC) method for the bionic eye system is proposed. The designed controller is model independent, and has the advantages of both simple structure, easy design of PD controller and strong robustness of SMC method with respect to system parameter uncertainty. Lyapunov techniques and LaSalle's invariance theorem are used to support the...
Image-guided navigation is an important component of the orthognathic assisted robot, and it allows the robots to operate in precise accordance with a preoperative virtual plan. However, the present commercially available image-guided navigation systems, which use infrared-based tracking, cant guide the relocation of the bone in the orthognathic operation, that means they are not suitable for orthognathic...
Grey forecasting model is an important part of grey theory, and it is an important tool to deal with small samples and poor information. The grey GM(1,1) model is one of the most important forecasting models. In recent years, the GM(1,1) model has been widely used in industrial production, social science and other fields. However, the GM(1,1) model has a large error in the practical application process,...
To facilitate understanding of the relationship between the most significant greenhouse gas carbon dioxide and human activities, we have developed a differential absorption lidar (DIAL) detection system at 1.57 μm. The goal of this lidar system is to detect the temporal and spatial distribution of atmospheric carbon dioxide gas from 0.3 km to 3 km in the atmosphere. Beginning in 2009, the system was...
The modular multilevel converter (MMC) is a competitive candidate for VSC-HVDC systems. However, the conventional HB-MMC can't block dc link fault current because of the freewheeling effect of diodes. To solve this problem, researchers proposed an account of sub-modules (SMs) with DC-fault current clearing capability. This paper summarizes the 2 basic criteria and provides a comprehensive review of...
Solid state transformer (SST) has recently attracted much attention due to its great potential of being applied in the future smart grid. Modular structure is commonly employed in SST, which makes it possible to enhance the reliability of the system by introducing redundancy fault-tolerant control (RFC). This paper presents a general design of 10kV/1MW SST with 800V DC bus, and the various RFC strategies...
With the widespread use of solar energy, the grid-connected photovoltaic (PV) systems based on solid state transformer (SST) have considerable prospect. This paper presents the design and demonstration of a three-phase 800-V/10-kV 1-MW SST for grid-connected PV system. The topology of the 10-kV/1-MW SST is designed as a modular structure containing the dual active bridge (DAB) converter and full bridge...
This study presents a data-driven method for fault detection and diagnosis. Aiming at the problem of low diagnosis accuracy and not easy to obtain faulty data, the neighborhood rough set and signed directed graph are combined together to improve the diagnosis efficiency without prior knowledge. The node status in signed directed graph is described as a continuous fuzzy membership degree. The diagnosis...
Object tracking is an important capability for robots tasked with interacting with humans and the environment, and it enables robots to manipulate objects. In object tracking, selecting samples to learn a robust and efficient appearance model is a challenging task. Model learning determines both the strategy and frequency of model updating, which concerns many details that can affect the tracking...
A three-phase solid state transformer (SST) based on serial H-bridge multilevel converter, with advantages as expandable modular structure, controlled power quality and low dependence on copper/steel, is applied to replace the traditional line frequency step-up transformer on PV generation. Because of the input-parallel output-serial dual active bridge (DAB) based submodules with inner dc links, the...
This paper presents a novel designed SiC MOSFET module based on low-inductance layout using split damping capacitors. The voltage rating of this power module is 1200V and the current rating is 288A. The influence of parasitic inductance on SiC MOSFET in one-phase-leg module is analyzed, and the design of the SiC MOSFET module is also described in this work. The double pulse test is used to evaluate...
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