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Shen G.,Nanjing University of Information Science and Technology | Xu Y.,Science and Technology on Near surface Detection Laboratory | Liu B.,Nanjing University of Information Science and Technology
Desalination and Water Treatment | Year: 2016

Carbon materials are effective for removal of both toxic inorganic and organic substances. In this study, a novel magnetic mesoporous carbon aerogel which combined high specific surface area, adsorption capacity and magnetic property of Fe3C was prepared by citrate sol-gel method. The as-prepared samples were characterized by powder X-ray diffraction, TEM, scanning electron microscope, and BET methods. Results show that the aerogel has the specific surface and average pore size of 290 m2/g and 2.7 nm, respectively. Magnetic Fe3C nanoparticles were dispersed uniformly in carbon matrix and exhibit excellent response to an external magnetic field. As a result, the adsorbent can be easily separated from solution using an external magnetic field. Batch experimental results on As(V) removal showed that the adsorption kinetics and isotherm data were fitted well by a pseudo-second-order model and a Freundlich model, respectively. The monolayer adsorption capacity (qm) of the adsorbent was calculated to be 56.2 mg/g at pH 7.0. The excellent uptake capability of the magnetic mesoporous materials make it be potentially attractive materials for removal of hazardous substances from water. © 2016 Balaban Desalination Publications. All rights reserved. Source


Yang M.,Nanjing Southeast University | Yin X.,Nanjing Southeast University | Chen Z.N.,National University of Singapore | Rong Y.,Science and Technology on Near surface Detection Laboratory | Qian H.,Science and Technology on Near surface Detection Laboratory
IEEE Antennas and Wireless Propagation Letters | Year: 2016

A planar bow-tie antenna loaded with open stubs is proposed to realize image rejection and gain enhancement for superheterodyne applications. The loading open stubs are two open-circuit double-sided parallel-strip lines symmetrically connected to the feedline of a planar bow-tie antenna, which functions as a bandstop filter in frequency band lower than the operating frequency to reject image interference and simultaneously as a reflector across the operating frequency band to enhance the antenna gain. Simulated results show that the realized gain of the proposed antenna in the main radiation direction is suppressed by 25 dB at the image frequency and is enhanced by about 3 dB at the operating frequency compared to that of an unloaded antenna. Good agreements between the simulated and the measured results have been observed. © 2015 IEEE. Source


Xu P.,Wuhan Naval University of Engineering | Xu P.,Science and Technology on Near surface Detection Laboratory | Yan B.,Wuhan Naval University of Engineering | Hu S.,Science and Technology on Near surface Detection Laboratory
Cluster Computing | Year: 2016

An algorithm to improve direction of arrival (DOA) estimation accuracy with an extended sensor array in the presence of multiple coherent signal sources is proposed. The algorithm uses virtual element theory to extend the sensor array, estimates virtual element information via linear prediction and expands the array aperture in practical sense; the sparsity of the target orientation in angle space is exploited to establish an over-complete dictionary and a reception model for the array signal in sparse space; the received array data is preprocessed using singular value decomposition (SVD) method and target DOA estimation is realized by calculating the best atoms. The algorithm improves DOA estimation accuracy by extended array and uses SVD to control computational complexity effectively, which ensures the accuracy and efficiency. Computer simulation shows that the proposed algorithm is able to accurately estimate the DOA for both single-target and closely spaced multi-target cases in low signal-to-noise ratio environments, and also has excellent DOA estimation performance in the presence of multiple coherent signal sources. © 2016 Springer Science+Business Media New York Source


Du K.,PLA University of Science and Technology | Du K.,Science and Technology on Near surface Detection Laboratory | Fang X.,PLA University of Science and Technology | Zhang W.-P.,PLA University of Science and Technology | Ding K.,Science and Technology on Near surface Detection Laboratory
Shock and Vibration | Year: 2016

Seismic waves are widely used in ground target classification due to its inherent characteristics. However, they are often affected by extraneous factors and have been found to demonstrate a complicated nonlinear characteristic. The traditional signal analysis methods cannot effectively extract the nonlinear features. Motivated by this fact, this paper applies the fractal dimension (FD) based on morphological covering (MC) method to extract features of the seismic signals for ground targets classification. With the data measured from test field, three different schemes based on MC method are employed to classify tracked vehicle and wheeled vehicle in different operation conditions. Experiment results demonstrate that the three proposed methods achieve more than 90% accuracy for vehicle classification. Copyright © 2016 Kai Du et al. Source


Qi H.,Nanjing Southeast University | Yin X.,Nanjing Southeast University | Liu L.,Nanjing University of Posts and Telecommunications | Rong Y.,Science and Technology on Near surface Detection Laboratory | Qian H.,Science and Technology on Near surface Detection Laboratory
IEEE Antennas and Wireless Propagation Letters | Year: 2016

This letter introduces an effective solution for improving isolation between closely spaced patch antennas. A satisfactory isolation is realized by three interdigital lines that excite an orthogonal polarization mode on the adjacent patch. A two-patch array is simulated and fabricated to verify the decoupling effectiveness of the proposed structure. The investigations of the electric field and current distributions reveal the working mechanism of the proposed structure. The experimental results show that the achieved isolation is better than 20 dB, and the maximum isolation enhancement is 24.7 dB, with a compact edge-to-edge separation of just 0.07λ0. Moreover, the proposed structure can also be applied for the decoupling of a multielement patch array. © 2002-2011 IEEE. Source

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