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Zero index metamaterials (ZIM) experience near-perfect spatial coherence and infinite spatial wavelength. We model, through both analytical calculations and simulations, superradiant emission of silicon vacancy centers (SiV) in a diamond ZIM that extends well beyond the emission wavelength near 737 nm.
We present small-footprint à λ/2-wide) silicon-based waveguides with an effective index of zero at a wavelength near λ = 1630 nm. We characterize the refractive index using on-chip interferometry and measure the propagation loss to be 1.3 dB/μm.
We achieve strong local-field enhancement within a novel inhomogeneous metamaterial whose graded refractive index is realized using Dirac-cone metamaterials. This transition metamaterial provides a powerful tool for sensing, nonlinear optics, and quantum optics.
Harmonic resonance issues have been attracted more and more attention due to a large number of power electronic inverters being used in power systems. In this paper, in order to have a deep insight into resonances, the singular value sensitivities with respect to component parameters of the network and the control parameters of inverters are used for harmonic resonance analysis based on Singular Value...
In the paper, a nonlinear modeling approach for a class of unmanned-aerial-vehicle (UAV) helicopters is presented. The applied approach adopts a component buildup method to calculate the component forces and moments. In order to improve the modeling accuracy and applicability, the rotor dynamics are detailedly analyzed by taking into account the influences of airspeed in hub center and the coupling...
The design of radar waveforms needs to deal with ambiguity resolution both in range and Doppler. Particularly, the waveforms of Pulse Doppler (PD) radars using low pulse repetition frequency(PRF) waveforms are unambiguous in range but ambiguous in Doppler. To solve the problem, the existing detection algorithms are mostly based on the Chinese Remainder Theorem (CRT), but these algorithms do not have...
Named Data Networking (NDN) is a clean state Internet paradigm that considers some security primitives in its original design, and one of the promising candidates for the future Internet architecture. However, it may suffer from the specific threats such as Interest Flooding Attacks (IFA). Most researches are focused on the defense against fake IFA, where the PIT resources in victim routers are exhausted...
Content-Centric Networking (CCN) proposals rethink the communication model around named data. In-network caching is a fundamental feature to distinguish the CCN from the current host-centric IP network. In this paper, we have proposed a hybrid caching scheme which combines the on-path one and the off-path one. We leverage the ISOMAP manifold learning algorithm to distinguish the importance of nodes...
In all the security issues in wireless sensor networks (WSNs), session key exchange is fundamental one with a great challenge. Owning to the semi-group property and one-way trapped characteristic of Chebyshev polynomials, an enhanced key exchange scheme based on Chebyshev chaotic map for WSNs was proposed in this paper. Our scheme aims at increasing the security of the session key between nodes. According...
This paper researches on millimeter-wave (mm-wave) channel estimation based on interference cancellation (IC) and DOA (Direction of Angles) estimation in hybrid massive MIMO systems. According to the ray-tracing model, the mm-wave channel estimation problem can be solved by converting into the estimation of parameters including the angles of departure (AOD), the angles of arrival (AOA) and the path...
In this paper, a novel pilot extension scheme is proposed for massive MIMO uplink transmission, and its performance is evaluated analytically. Specifically, we divide the cell users into two groups, namely near users and far users, according to their distances to the service base stations. The far users are more motivated to mitigate the inter-cell interference than the near users at the price of...
This paper introduces a real-time energy management strategy for hybrid electric vehicles (HEVs), called as RB-ECMS, which combines rule-based (RB) control and equivalent consumption minimization strategy (ECMS). Three working modes of the HEVs, motor/engine separately propelling the vehicle, and motor and engine jointly propelling the vehicle, is first divided by the rule-based control, and while...
The transmission factor of a dipole to dipole and a loop to loop through homogenous human muscle equivalent material is investigated using the FDTD analysis. The transmission factors of the dipole system and the loop system are compared and the optimization of antenna type and the optimal frequency is also discussed. In the case of dipole system, a local maximum of transmission factor is observed...
Real-time demand response pricing mechanism can guide electricity consumption habits through price signals, thereby saving costs and improving the quality of the electricity curve. In this paper, the carbon emission permits trade mechanism is introduced into real-time electricity price (RTP) mechanism. Under the basic principle of carbon trading and the traditional unit commitment model, an economic...
A high breakdown voltage AlGaN/GaN HEMTs is fabricated by using source-connected field plate (SCFP) in Dynax. The output capacitance (Cds) of this device shows a strong dependence on Vds. A modified Angelov large signal model considering Cds nonlinearity is presented to achieve a more accurate simulation on efficiency and linearity. The small signal simulation results indicate that the proposed nonlinear...
While the memory footprints of cloud and HPC applications continue to increase, fundamental issues with DRAM scaling are likely to prevent traditional main memory systems, composed of monolithic DRAM, from greatly growing in capacity. Hybrid memory systems can mitigate the scaling limitations of monolithic DRAM by pairing together multiple memory technologies (e.g., different types of DRAM, or DRAM...
In most studies on vascular shear wave imaging (SWI), longitudinal section is mainly concerned, and the radial motion and reflected waves are not considered in cross section. It is important to investigate the SWI in cross section when evaluating the anisotropy of the vessel wall or the complete plaque composition. In our previous study, a novel method based on coordinate transformation and directional...
In vivo measurement of the mechanical properties of thin-walled soft tissues (e.g., mitral valve, artery and bladder) and in situ mechanical characterization of thin-walled artificial soft biomaterials in service are of great challenge. Those thin-walled structures are usually pre-stressed to achieve and/or improve their functional performance, which further complicate the inverse analysis to identify...
Intravascular ultrasound (IVUS) has frequently been used by the cardiologist to diagnose atherosclerosis and guide the interventional procedures. IVUS has gained widely clinical acceptance over the past twenty years because of its superior capability to assess plaque burden and monitor artery remodeling, which also makes it as the irreplaceable image modality for most innovative multimodality intravascular...
Rotate Vector (RV) reducer is widely used in robotics because of its high precision and stiffness. However, the long-term operation leads to unpredictable reducer failures due to the inevitable abrasions of mechanical parts. To this end, this paper is intentionally designed to diagnose the RV reducer crankshaft abrasion faults using acoustic emission (AE) techniques. Firstly, the AE signal features...
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