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In this study, numerical investigations of flow characteristics of a pumpjet propulsor based on Computational Fluid Dynamics (CFD) method have been presented. The Zwart-Gerber-Belamri (Z-G-B) cavitation model based on the Reynolds Averaged Navier-Stokes (RANS) method is employed. The structured gird is applied. A four-blade skewed E779A propeller has been used to verify the numerical method. The comparison...
Image compression plays more and more important role in image processing. Image sparse coding with learned over-complete dictionaries shows promising results on image compression by representing images with dictionary atoms compactly. Within the sparse coding based compression framework, a sparse dictionary is first learned from training images in a predefined image library, and then an image is compressed...
In this paper, a method is proposed for classification of patients with disorder of consciousness (DOC) based on the diffusion tensor imaging (DTI) sequences analysis. The patients are divided into vegetative state (VS) and minimally consciousness state (MCS). Firstly, tract-based spatial statistics (TBSS) was applied to find the regions of interest (ROIs), and the values of fractional anisotropy...
We experimentally demonstrate the connection of two multipartite entangled states by quantum entanglement swapping. The results provide a feasible technical reference for constructing more complicated quantum networks.
Two kinds of wavelength-tunable thermal sources at 3–5 urn mid-infrared atmospheric window are experimentally demonstrated with simple layered structures by controlling the intermediate phases of Ge2Sb2Te5 (GST).
InAs/InAlGaAs quantum dot microdisk lasers were epitaxially grown on Si (001) substrates by MOCVD. CW lasing at 1544 nm was achieved at 4.5 K, with a low threshold of 230 μW and quality factor of 2200.
A switchable, tunable and wavelength-selective thermal emitter is experimentally demonstrated with simple layered structures by controlling the phases of Ge2Sb2Te5, achieving a high emission extinction ratio of 11dB.
We propose to separate out the toroidal multipoles in the polar coordinates that is simpler than previous methods done in the Cartesian coordinates. We uncover higher order current configurations other than the toroidal electric multipole.
We demonstrate the first electrically pumped quantum-dot micro-ring lasers epitaxially grown on (001) silicon. Continuous-wave lasing around 1.3 μm was achieved with ultra-low thresholds as small as 0.6 mA and maximum operation temperatures up to 100°.
This paper proposes a multiperiod optimal dispatch model for hybrid voltage source converter based multi-terminal DC (VSC-MTDC) system and AC grids with consideration of optimal coordination of offshore wind farm (OWF) and battery energy storage (BES). The OWF is connected to onshore AC grid by VSC-MTDC. The VSC capacity limits and Grid Code for OWF connection to AC grid are taken into consideration...
Omnidirectional wireless power transfer (WPT) system has been studied recently due to its better user experience compared with directional WPT system. And this paper focus on resonant converter topologies study in omnidirectional WPT system. At first, three challenges of resonant converter design are identified: I. moving resonant frequency under variable coupling condition; II. voltage controllability...
In this paper, a new critical-conduction-mode (CRM)-based modulation is proposed for three-phase inverters. With this modulation, soft switching is achieved and the efficiency of the inverter is improved, especially for high frequency operation with SiC MOSFET. In three-phase string PV inverter applications, by operating at switching frequency above 300 kHz, power density of the inverter is estimated...
Wide-band-gap devices can provide much faster switching speed. But the dv/dt of switching node voltage also becomes much higher, causing potential common mode noise issue. On the other hand, PCB winding transformer has significant large inter-winding capacitance, which provides a low impedance path for common mode noise. In this paper, a symmetrical resonant converter as well as a symmetrical PCB...
48V voltage regulator modules (VRMs) are critical for telecom power supplies, and is becoming popular for future data centers. By using a novel sigma converter topology, an outstanding performance in terms of efficiency (94%) and power density (420 W/in3) have been demonstrated in [11]. Both the efficiency and power density are much higher than state-of-art solutions. The sigma converter is a quasi-parallel...
A deadbeat predictive control based current sensorless control method is proposed as a backup method in this paper, by replacing the current feedback with the predicted current at one sampling period ahead, the feedback current information is not needed, thus current sensors can be omitted. Noticing that parameter mismatch will largely influence the control performance of predictive control, q axis...
This paper proposes an optimal locating and sizing method of distributed generations (DGs) considering local consumption and power export potential. Based on the analysis of seasonal and temporal characteristics of different types of DGs and load, the proposed DGs locating and sizing model, is to minimize the total costs of DGs depreciation, network power losses, and redundant power. Under the premise...
As the deep learning exhibits strong advantages in the feature extraction, it has been widely used in the field of computer vision and among others, and gradually replaced traditional machine learning algorithms. This paper first reviews the main ideas of deep learning, and displays several related frequently-used algorithms for computer vision. Afterwards, the current research status of computer...
In this paper, a novel dual-band suspended stripline (SSL) filter is proposed. Based on traditional designing technique, a band-pass SSL filter is designed. Considering the unique properties of metamaterials, we apply it to the filter structure designing. Metamaterials can produce negative permittivity and thus there forms a dual-band. The simulated results exhibit low insertion loss, high selectivity...
In-memory key-value store is a crucial building block of large-scale web architecture. Given the growth of the data volume and the need for low-latency responses, cost-effective storage expansion and fast large-message processing are the major challenges. In this paper, we explore the design of key-value middleware that takes advantage of modern NVMe SSDs and RDMA interconnects to achieve high performance...
As a meaningful and typical application scenario of Internet of Things (IoT), Internet of Vehicles (IoV) has attracted a lot of attentions to solve the increasingly severe problem of traffic congestion and safety issues in smart city. Information-centric networks (ICN) is a main stream of next generation network because of its content based forwarding strategy and in-network caching properties. Many...
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