Harbin, China

Harbin Engineering University , also referred to as HEU, was founded in 1953 in Harbin, China. It offers over 150 degree programs, 48 of which are conducted in English. Designated a Project 211 university, HEU is billed as a top institution for engineering and marine projects. Wikipedia.


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Liu M.,Harbin Institute of Technology | Zhang L.,Harbin Institute of Technology | Shi P.,University of Adelaide | Shi P.,Victoria University of Melbourne | Zhao Y.,Harbin Engineering University
Automatica | Year: 2017

This paper investigates the design problem of sliding mode control for a class of continuous-time Markovian jump systems with digital communication constraints. Two types of classical quantization schemes, that is, dynamical uniform quantizer and static logarithmic quantizer, are employed to perform the design work, respectively. In this study, a novel quantized sliding mode control design method is developed to stabilize the closed-loop systems in the presence of both state and input quantization and unknown time-varying actuator faults. Under the proposed quantized control strategies, the quantization effects can be completely compensated via injecting quantizer parameters into the controller gains. Moreover, in both quantization cases, the proposed robust quantized sliding mode controllers can guarantee the state trajectories of the closed-loop systems to be mean-square stable, and ensure the reachability of the specified sliding surface with probability 1 at the same time. Finally, a numerical example with an F-404 aircraft engine system is provided to show the effectiveness of the proposed digital control design approach. © 2017 Elsevier Ltd


Xu H.,Harbin Engineering University | Gu H.,Harbin Engineering University | Sun Z.,Harbin Engineering University
International Journal of Heat and Mass Transfer | Year: 2017

An experimental investigation on condensation heat transfer characteristics of steam in the presence of multicomponent noncondensable gases in a horizontal tube is conducted in the present research. The experimental runs are carried out at a volume ratio of helium and noncondensable gases varying from 0% to 90%, the mixture gases pressure between 0.13 and 0.2 MPa, over the mixture gases velocity changing from 8 to 34 m/s, covering all the major flow patterns inside a pipe. The effects of inner wall subcooling, mixture gases velocity and pressure on local heat transfer coefficient have been analyzed for annular, wavy and stratified flow. The change of the condensation heat transfer capacity for different volume ratios of helium in the noncondensable gases have been studied at the same time. The results indicate that the local heat transfer coefficient increases with the increasing wall subcooling for annular and wavy flow but decreases for stratified flow. With the flow regime transforming from annular to stratified flow, the active influence of the gases velocity is gradually weakened and the local heat transfer coefficient even starts to decrease when it reaches stratified flow. For all flow patterns, the increases of helium volume fraction and mixture gases pressure always enhance the condensation heat transfer. Based on the experimental analysis, an empirical correlation for predicting the local heat transfer coefficient is proposed. The comparison of the calculated results and the experimental data shows that the present correlation can give satisfactory engineering accuracy. © 2016 Elsevier Ltd


Ma Q.W.,Harbin Engineering University | Ma Q.W.,City University London
European Journal of Mechanics, B/Fluids | Year: 2017

This paper presents an experimental study on inertial hydrodynamic behaviors of an open-frame remotely operated vehicle (ROV) that has a complex open-frame hull but a large capacity to hold more instruments on board than those of other ROVs. A 1:4 scaled model was tested by a vertical planar motion mechanism in a circulating water channel of Harbin Engineering University. The inertial coefficients, which can be used for the simulation of motions and therefore for the maneuverability of the ROV, were calculated. Particular attention was paid to discuss the properties of the cross-inertial coefficients, which are related to the inertial forces/moments induced by the motion in other directions. © 2017 Elsevier Masson SAS


Chu Z.,Harbin Engineering University | Wu Y.,Harbin Engineering University | Zhuang J.,State University of New York at Buffalo
Waste Management and Research | Year: 2017

This article aims to design an increasing block pricing model to estimate the waste fee with the consideration of the goals and principles of municipal household solid waste pricing. The increasing block pricing model is based on the main consideration of the per capita disposable income of urban residents, household consumption expenditure, production rate of waste disposal industry, and inflation rate. The empirical analysis is based on survey data of 5000 households in Beijing, China. The results indicate that the current uniform price of waste disposal is set too high for low-income people, and waste fees to the household disposable income or total household spending ratio are too low for the medium- and high-income families. An increasing block pricing model can prevent this kind of situation, and not only solve the problem of lack of funds, but also enhance the residents' awareness of environmental protection. A comparative study based on the grey system model is made by having a preliminary forecast for the waste emissions reduction effect of the pay-as-you-throw programme in the next 5 years of Beijing, China. The results show that the effect of the pay-as-you-throw programme is not only to promote the energy conservation and emissions reduction, but also giving a further improvement of the environmental quality. © The Author(s) 2017.


Liu G.,Harbin Engineering University | Li X.,Zhejiang GongShang University | Campos L.C.,University College London
Journal of Water Supply: Research and Technology - AQUA | Year: 2017

Surface properties of activated carbons play vital roles in adsorption of contaminants. Aiming to improve the adsorption of phenolic endocrine disrupting chemicals (EDCs), commercially activated carbon (W20) was modified via thermal treatment to obtain a carbon sample (W20N) with different characteristics. The content of acidic oxygen-containing groups of W20 was obviously reduced by the thermal modification. Bisphenol A (BPA) was chosen as the target compound. The adsorption results indicated that the acidic oxygen-containing groups (especially carboxyl groups) on the surface of activated carbons weakened the ability of carbon acting as π-donors that lead to the reduction of BPA adsorption. Compared to W20, W20N with a greater number of phenyl groups exhibited higher adsorption capacity for BPA in a wide range of pH (4.0-10.0). Therefore, thermal modification improved BPA adsorption onto activated carbon. Furthermore, thermodynamic analysis and effect of solution pH revealed that BPA adsorption onto W20 and W20N probably followed face-to-face π-π dispersion interactions. Coexisting tannic acid (TA) formed BPA-TA complexes and played a negative role in BPA adsorption onto carbon based on the π-π dispersion interaction. This study should help broaden the scope of modification methods and the application of activated carbons to enhance the removal of phenolic EDCs. © IWA Publishing 2017.


Baozhi C.,Harbin Engineering University | Baozhi C.,Daqing Normal University
2016 1st IEEE International Conference on Computer Communication and the Internet, ICCCI 2016 | Year: 2016

Anomaly target detection of hyperspectral image has become a hot in remote sensing research field, the paper is studied on the popular sparse representation method of anomaly target detection, and which are compared with traditional algorithm, such as the generalized likelihood ratio detection KRX and RX algorithm. The results show very good detection performance for sparse representation method of anomaly target detection. At last, the simulation results demonstrate that the proposed sparse representation algorithm outperforms the other algorithm, it is higher precision and lower false alarm rate. © 2016 IEEE.


Qi H.,Harbin Engineering University | Zhang X.-M.,Harbin Engineering University
Waves in Random and Complex Media | Year: 2017

With the aid of the Green function method and image method, the problem of scattering of SH-wave by a semi-cylindrical salient near vertical interface in bi-material half-space is considered to obtain its steady state response. Firstly, by the means of the image method, Green function which is the essential solution of displacement field is constructed to satisfy the stress-free condition on the horizontal boundary in a right-angle space including a semi-cylindrical salient and bearing a harmonic out-of-plane line source force at any point on the vertical boundary. Secondly, the bi-material is separated into two parts along the vertical interface, then unknown anti-plane forces are applied on the vertical interface, and according to the continuity condition, the first kind of Fredholm integral equations is established to determine unknown anti-plane forces by “the conjunction method”, then the integral equations are reduced to the linear algebraic equations by effective truncation. Finally, the dynamic stress concentration factor (DSCF) around the edge of semi-cylindrical salient is calculated, and the influences of incident wave number, incident angle, effect of interface and different combination of material parameters, etc. on DSCF are discussed. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Li T.,Harbin Engineering University | Yuan G.,Harbin Engineering University
Journal of Computational and Theoretical Nanoscience | Year: 2016

High pressure waterjet drilling (HPWD) as a cutting-edge upstream technology receives considerable attention in horizontal drilling fields. HPWD technology achieves great commercial benefits for the reentry multilateral well drilling in small diameter space where the conventional rotary drill bit needs high-cost tools to implement. The sophisticated waterjet downhole drilling environments are difficult to predict because the temperatures and pressures varied with the depth of the well and the chemical compositions of drilling fluid. Different proportion of waterjet drilling fluid (density or viscosity) may produce different pressures and temperatures for the waterjet drilling bit. Therefore, computational fluid dynamics (CFD) simulation of the waterjet drilling environments is of crucial significance, especially for the design of downhole navigation apparatus. This paper describes the design details of helix drilling calibration (HIDC) apparatus with MEMS gyroscope based measurement while drilling (MGWD) device in downhole harsh conditions. The design objective of HIDC apparatus is that the determined errors of MGWD device interrupted by scale factor errors and axis non-orthogonal errors can be modulated and the stochastic errors and the bias drift of MGWD device can be reduced. The drilling environments of HIDC apparatus are simulated by ANSYS INFLUENT software and the simulation results demonstrate that the temperature, the pressure and the flow rate of waterjet drilling fluid to HIDC apparatus are 172.85 °C, 4×108 Pa and 704.4823 m/s respectively. © Copyright 2016 American Scientific Publishers All rights reserved.


Wang H.,Harbin Engineering University | Lu Z.,Harbin Engineering University
Journal of Computational and Theoretical Nanoscience | Year: 2016

In this paper, a new algorithm is proposed to retrieve wind direction from marine X-band radar image-sequences. This method is based on piecewise fitting technique which can reduce the effect of radar radial attenuation through correcting radar image-sequences. Wind direction is found using energy spectrum of wind-induced streaks, which is obtained through establishing energy spectrum scale separation filter and the characteristics of wind streaks, two dimensions FFT is used to obtain the energy spectrum of radar images. Compared to local gradient method (LGM), this method doesn't need to find the right image resolution for retrieving. The comparison of the wind directions measured by in-situ vane and retrieved from marine X-band radar image sequences have a correlation coefficient of 0.99, with a bias of -0.64° and a standard deviation of 8.29, which indicate that the proposed method is reasonable. © 2016 American Scientific Publishers All rights reserved.


Xia G.-Q.,Harbin Engineering University | Zhao A.,Harbin Engineering University
Journal of Computational and Theoretical Nanoscience | Year: 2016

This paper focuses on discussing the problem of identifying a continuous-time (CT) mathematical model for the dynamics of a Dynamic Positioning (DP) ship. The model of the ship is considered as a black box and is identified by applying the subspace identification method for the first time. The identification problem is first transformed from time domain into the all-pass domain using Laguerre filters applied to the sampled input/output data. Then Continuous-Time Predictor-Based Subspace Identification algorithm (CT-PBSID) can be used to identify the transformed model. At last, the system matrices of the continuous-time state space model of the ship can be extracted through bijective mapping. By using the data collected from the identification experiments carried on the DP-3 simulation system, the feasibility and effectiveness of CT-PBSID is verified, and the identified continuous-time model can well establish the characteristics of a DP ship. © 2016 American Scientific Publishers All rights reserved.


Yu-Long H.,Harbin Engineering University | Yong-Gang Z.,Harbin Engineering University
Asian Journal of Control | Year: 2017

In this paper, a new particle smoother based on forward filtering backward simulation is developed to solve the nonlinear and non-Gaussian smoothing problem when measurements are randomly delayed by one sampling time. The heart of the proposed particle smoother is computation of delayed posterior filtering density based on stochastic sampling approach, whose particles and corresponding weights are updated in Bayesian estimation framework by considering the one-step randomly delayed measurement model. The superior performance of the proposed particle smoother as compared with existing methods is illustrated in a numerical example concerning univariate non-stationary growth model. © 2016 Chinese Automatic Control Society and John Wiley & Sons Australia, Ltd


Tang D.,Harbin Engineering University | Yao X.,Harbin Engineering University | Wu G.,Harbin Engineering University | Peng Y.,China Ship Development And Design Center
Thin-Walled Structures | Year: 2017

A semi-analytical procedure for free and forced vibration analysis of multi-stepped circular cylindrical shell with arbitrary boundary conditions is developed with the employment of the method of reverberation-ray matrix. Based on the Flügge thin shell theory, the equations of motion of the circular cylindrical shell are introduced and exact solutions of the traveling wave form along the axial direction and the standing wave form along the circumferential direction are obtained for each segment of uniform shell. With such a unidirectional traveling wave form solution, the method of reverberation-ray matrix is adopted to calculate natural frequencies and steady-state responses of the multi-stepped circular cylindrical shell. Comparisons of the present results with those previously published in literature and those obtained by the finite element method prove that the method of reverberation-ray matrix is applicable and of high precision for free and forced vibration analysis of the multi-stepped circular cylindrical shell. Effects of elastic support stiffness and the number of steps on natural frequencies are investigated. © 2017 Elsevier Ltd


Liu C.,Harbin Engineering University | Li Y.,Harbin Engineering University | Nie W.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

This paper includes mixed matrix estimation of underdetermined blind source separation (UBSS) under the anechoic mixing model and introduces single source points to the anechoic mixing model. First, we adopt a clustering algorithm to get the amplitude in the mixing matrix. Then, utilizing the amplitudes, We use a single source point detection method to determine the presence of only one source signal. This algorithm finds that single source points by using the real and the imaginary parts of the TF coefficients of mixed signals. Finally, using the points of single source cluster to obtain the mixing matrix. The results of our experiments indicate it can calculate the mixing matrix accurately under the condition when there are more sources using the proposed algorithm. © 2016 IEEE.


Dai J.,Harbin Engineering University | Lv W.,A+ Network | Ye F.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

As the explosive growth of wireless date requirements, heterogeneous network (HetNet) has become an effective solution for improving the system performance such as the throughput. The femtocells are always arranged to share the spectrum with the macro base stations (MBSs). Thus, the co-channel interference leads to the degradation of the HetNet throughput. In this paper, we discuss the program of spectrum reuse in the two-tier HetNet, and the problem is defined as a Stackelberg game approach. The MBS is play as a leader and it releases a part of spectrum resource for femtocells to avoid intertier interference. And the femtocells provide services to fractional macro users (MUEs) in return. Therefore, the throughput can be improved by the reduction of the inter-tier interference. Compared with the former works, the prominent characteristic of the method in the paper is that the benefit relation between the leader and followers is not measured by the real money. Furthermore, considering the system throughput specifically, we define the utility of the femto base stations (FBSs) by the average throughput as same as the utility of the MBS, which is used to improve the overall throughput of the system. Moreover, the gradient descent algorithm is also applied to compute the Nash equilibrium as the range of variables become continuous. The simulation results indicate that the proposed algorithm can observably reduce the interference and enhance the throughput of the network. © 2016 IEEE.


Yang Z.,Harbin Engineering University | Li Y.,Harbin Engineering University | Ye F.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

Communication signal and noise's waveform can be described and distinguished by fractal theory with their irregular characteristics. In current cognitive radio system, single node spectrum sensing is susceptible to noise uncertainty and its detection accuracy in low SNR situation is poor. To solve these issues, a cooperative spectrum sensing algorithm based on Katz fractal dimension is proposed. It detects Primary user's signals that is according to the difference between noise and Katz fractal dimension's characteristics in frequency domain multi-user environment. Simulations and analyses of the proposed method show some advantages by comparing with cooperative spectrum sensing algorithm based on box dimension and traditional energy detection method, such as insensitive to noise uncertainty, high detection accuracy in low SNR situations, not requiring for priori knowledge of primary user, and less affected by modulation parameters. © 2016 IEEE.


Liu B.,CAS Changchun Institute of Applied Chemistry | Li C.,Zhejiang Normal University | Yang P.,Harbin Engineering University | Hou Z.,CAS Changchun Institute of Applied Chemistry | Lin J.,CAS Changchun Institute of Applied Chemistry
Advanced Materials | Year: 2017

808 nm-light-excited lanthanide (Ln3+)-doped nanoparticles (LnNPs) hold great promise for a wide range of applications, including bioimaging diagnosis and anticancer therapy. This is due to their unique properties, including their minimized overheating effect, improved penetration depth, relatively high quantum yields, and other common features of LnNPs. In this review, the progress of 808 nm-excited LnNPs is reported, including their i) luminescence mechanism, ii) luminescence enhancement, iii) color tuning, iv) diagnostic and v) therapeutic applications. Finally, the future outlook and challenges of 808 nm-excited LnNPs are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gao H.,Harbin Engineering University | Du Y.,Harbin Engineering University | Diao M.,Harbin Engineering University
International Journal of Computing Science and Mathematics | Year: 2017

In order to solve discrete optimisation problem, a novel intelligence algorithm called as quantum-inspired glowworm swarm optimisation (QGSO) is proposed. By hybridising the glowworm swarm optimisation, quantum coding and quantum evolutionary theory, the quantum state and binary state of the quantum glowworms can be well evolved by simulated quantum rotation gate. The classical benchmark functions are used to test effectiveness of QGSO. The proposed QGSO algorithm is an effective discrete optimisation algorithm which has better convergent accuracy and speed. Then QGSO is used to resolve thinned array optimisation difficulties. Simulation results are provided to show that the proposed thinned array method based on QGSO is superior to the thinned array methods based on previous classical intelligence algorithms. The proposed thinned array method based on QGSO can search the global optimal solution of thinned array. Copyright © 2017 Inderscience Enterprises Ltd.


Ye F.,Harbin Engineering University | Dai J.,Harbin Engineering University | Li Y.,Harbin Engineering University
Symmetry | Year: 2017

In order to improve system performance such as throughput, heterogeneous network (HetNet) has become an effective solution in Long Term Evolution-Advanced (LET-A). However, co-channel interference leads to degradation of the HetNet throughput, because femtocells are always arranged to share the spectrum with the macro base station. In this paper, in view of the serious cross-layer interference in double layer HetNet, the Stackelberg game model is adopted to analyze the resource allocation methods of the network. Unlike the traditional system models only focusing on macro base station performance improvement, we take into account the overall system performance and build a revenue function with convexity. System utility functions are defined as the average throughput, which does not adopt frequency spectrum trading method, so as to avoid excessive signaling overhead. Due to the value scope of continuous Nash equilibrium of the built game model, the gradient iterative algorithm is introduced to reduce the computational complexity. As for the solution of Nash equilibrium, one kind of gradient iterative algorithm is proposed, which is able to intelligently choose adjustment factors. The Nash equilibrium can be quickly solved; meanwhile, the step of presetting adjustment factors is avoided according to network parameters in traditional linear iterative model. Simulation results show that the proposed algorithm enhances the overall performance of the system. © 2017 by the authors.


Chen Y.X.,Harbin Engineering University
International Journal of Simulation Modelling | Year: 2016

Production planning and the development of manufacturing production scheduling are two important operational management tasks. The results of these tasks will strongly influence the development of corporate profits, as well as the efficiency of utilization of resources. Considering the production scheduling problems in production plans can effectively avoid conflicts between the specific implementation production plan and the actual situations, and ultimately maximize resource utilization efficiency. This paper attempts to establish an integrated optimization model of production planning and scheduling with consideration of logistics constraints. A modified heuristic algorithm is proposed to solve this problem. In the final portion of this paper, a simulation analysis is given to demonstrate the outstanding advantage of the model and the algorithm, which gives further thought for the production planning. © 2016, Vienna University of Technology. All rights reserved.


Tang J.,University of Sichuan | Mo Z.,University of Sichuan | Sun L.,University of Sichuan | Yan C.,Harbin Engineering University
Experimental Thermal and Fluid Science | Year: 2017

In view of its super high ability of heat dissipation, Microbubble Emission Boiling (MEB) was investigated under atmospheric pressure and liquid subcooling of 0–60 K with the aid of a high-speed video camera. An experimental apparatus was designed and fabricated to achieve stable MEB, by which a more detailed bubble behaviors and heat transfer characteristics during MEB were obtained. It is reaffirmed that liquid subcooling of 20 K is the minimum subcooling triggering MEB for water. The increase in liquid subcooling would raise the wall superheat and vapor generation rate for forming MEB. The heat transfer coefficient in the beginning of MEB is about 20–70 kW/m2 K, less than that at CHF (Critical Heat Flux) under the same condition. Three typical interfacial phenomena were observed in MEB, which are partial collapse on the periphery of vapor film, partial collapse on the top of vapor film and violent surface wave process without collapse. The average collapse frequency in MEB is much higher than the bubble departure frequency in nucleate boiling, greatly enhancing the heat transfer process. Finally, a dimensionless heat transfer correlation for MEB is proposed with considering the effect of the vapor film collapse, condensation, Marangoni convection and vapor generation rate. © 2016 Elsevier Inc.


Teng X.,Harbin Engineering University | Dong H.,Harbin Engineering University | Zhou X.,Heilongjiang Provincial Corps Hospital Chinese Peoples Armed Police Forces
PLoS ONE | Year: 2017

Feature selection is an important preprocessing method in machine learning and data mining. This process can be used not only to reduce the amount of data to be analyzed but also to build models with stronger interpretability based on fewer features. Traditional feature selection methods evaluate the dependency and redundancy of features separately, which leads to a lack of measurement of their combined effect. Moreover, a greedy search considers only the optimization of the current round and thus cannot be a global search. To evaluate the combined effect of different subsets in the entire feature space, an adaptive feature selection method based on V-shaped binary particle swarm optimization is proposed. In this method, the fitness function is constructed using the correlation information entropy. Feature subsets are regarded as individuals in a population, and the feature space is searched using V-shaped binary particle swarm optimization. The above procedure overcomes the hard constraint on the number of features, enables the combined evaluation of each subset as a whole, and improves the search ability of conventional binary particle swarm optimization. The proposed algorithm is an adaptive method with respect to the number of feature subsets. The experimental results show the advantages of optimizing the feature subsets using the V-shaped transfer function and confirm the effectiveness and efficiency of the feature subsets obtained under different classifiers. © 2017 Teng et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Li N.,Harbin Engineering University | Liu H.,Beijing Institute of Machinery | Su Y.,Harbin Engineering University
PLoS ONE | Year: 2017

Numerical simulations are employed to study the hydrodynamics of self-propelled thunniform swimming. The swimmer is modeled as a tuna-like flexible body undulating with kinematics of thunniform type. The wake evolution follows the vortex structures arranged nearly vertical to the forward direction, vortex dipole formation resulting in the propulsion motion, and finally a reverse Kármán vortex street. We also carry out a systematic parametric study of various aspects of the fluid dynamics behind the freely swimming behavior, including the swimming speed, hydrodynamic forces, power requirement and wake vortices. The present results show that the fin thrust as well as swimming velocity is an increasing function of both tail undulating amplitude Ap and oscillating amplitude of the caudal fin θm. Whereas change on the propulsive performance with Ap is associated with the strength of wake vortices and the area of suction region on the fin, the swimming performance improves with θm due to the favorable tilting of the fin that make the pressure difference force more oriented toward the thrust direction. Moreover, the energy loss in the transverse direction and the power requirement increase with Ap but decrease with θm, and this indicates that for achieving a desired swimming speed increasing θm seems more efficiently than increasing Ap. Furthermore, we have compared the current simulations with the published experimental studies on undulatory swimming. Comparisons show that our work tackles the flow regime of natural thunniform swimmers and follows the principal scaling law of undulatory locomotion reported. Finally, this study enables a detailed quantitative analysis, which is difficult to obtain by experiments, of the force production of the thunniform mode as well as its connection to the self-propelled swimming kinematics and vortex wake structure. The current findings help provide insights into the swimming performance and mechanisms of self-propelled thunniform locomotion. © 2017 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Li Y.,Harbin Engineering University | Fang X.-X.,Harbin Engineering University
Proceedings - 2016 6th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2016 | Year: 2016

Aimed at the electromagnetic compatibility problems between same frequency radars on fleet battle ships, the maximum radar range is used to describe the EMC degree between the same frequency or similar frequency radars in radar system. The radar system is divided into Omani-directional antenna and directional antenna radar to analysis and get the two radar electromagnetic compatibility models, then the EMC degree model of entire radar system. Quantitative analysis of the simulation is represented for the relationship between several important parameters and EMC degree. It is an important complement of the radar deployment optimization methods, which provides a digital basis for analyzing the radars maximum benefit when coordinating combat. © 2016 IEEE.


Yu L.-S.,Harbin University of Science and Technology | Liu Y.-M.,Harbin Engineering University
Proceedings - 2016 6th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2016 | Year: 2016

Image segmentation is a key preprocessing step for object recognition and has a profound effect on the subsequent classification and recognition. Visual spatial clustering based segmentation is a commonly used method in image segmentation, which clusters pixels using visual descriptors by space similarity measure. It can achieve good results in simple image segmentation with less noise. This paper presents a segmentation method based on spatial position constraint of the pixel. The image is divided into overlapping rectangular blocks. By iteratively clustering these blocks with typical visual features and splitting the blocks with worse visual consistence, the spatial constraint information is added to the clustering process implicatively. The method is still unsupervised learning algorithm essentially by no guidance information provided beforehand. Experiments using real images are presented to show the efficiency of the proposed algorithm with better segmentation results than K-means.


Li F.,University of Siegen | Zhang C.,University of Siegen | Liu C.,Harbin Engineering University
Journal of Sound and Vibration | Year: 2017

A novel strategy is proposed to actively tune the vibration and wave propagation properties in elastic beams. By periodically placing the piezoelectric actuator/sensor pairs along the beam axis, an active periodic beam structure which exhibits special vibration and wave propagation properties such as the frequency pass-bands and stop-bands (or band-gaps) is developed. Hamilton's principle is applied to establish the equations of motion of the sub-beam elements i.e. the unit-cells, bonded by the piezoelectric patches. A negative proportional feedback control strategy is employed to design the controllers which can provide a positive active stiffness to the beam for a positive feedback control gain, which can increase the stability of the structural system. By means of the added positive active stiffness, the periodicity or the band-gap property of the beam with periodically placed piezoelectric patches can be actively tuned. From the investigation, it is shown that better band-gap characteristics can be achieved by using the negative proportional feedback control. The band-gaps can be obviously broadened by properly increasing the control gain, and they can also be greatly enlarged by appropriately designing the structural sizes of the controllers. The control voltages applied on the piezoelectric actuators are in reasonable and controllable ranges, especially, they are very low in the band-gaps. Thus, the vibration and wave propagation behaviors of the elastic beam can be actively controlled by the periodically placed piezoelectric patches. © 2017 Elsevier Ltd.


Song Z.-G.,Harbin Engineering University | Li F.-M.,Harbin Engineering University | Li F.-M.,Beijing University of Technology
Composites Part B: Engineering | Year: 2017

Sandwich structures with lattice core are novel composite structures, but the aeroelastic behaviors of them have not been fully studied. This paper is devoted to investigate the flutter and buckling properties of sandwich panels with triangular lattice core in supersonic airflow, and the active flutter and buckling control are also carried out, which can provide theoretical basis for the use of sandwich structures in the design of aircrafts. The unsteady aerodynamic pressure is evaluated by the supersonic piston theory in which the yawed flow angle is taken into account. Hamilton's principle with the assumed mode method is applied to formulate the equation of motion of the structural system. The active controller is designed by the displacement feedback method. Aeroelastic characteristics of the sandwich panels are studied, and the influences of the aerodynamic pressure on the frequency and mode shape of the panel are analyzed. The effects of yawed flow angle on the flutter properties of the sandwich panel are also analyzed. When considering the external in-plane load, the buckling behaviors of the sandwich panel are investigated. Moreover, the flutter and buckling properties between the sandwich and equivalent isotropic panels are compared to show the superior aeroelastic properties of the sandwich panels. The effects of piezoelectric patch placements on the active flutter control are analyzed. The optimal locations of piezoelectric actuator and sensor pairs are obtained by the genetic algorithm. The present study verifies that the sandwich structures have different aeroelastic and flutter suppression properties, which is useful in the research of lightweight sandwich materials. © 2016 Elsevier Ltd


Liu L.,Harbin Engineering University | Ma X.,Harbin Engineering University | Magagnato F.A.,Karlsruhe Institute of Technology
Fuel | Year: 2017

In order to meet the growing demand for reduction of pollutant emissions and improvement in thermal efficiency, advanced combustion modes, such as low-temperature combustion (LTC), premixed charge compression ignition (PCCI), have been adopted in modern diesel engines. Compared to conventional diesel combustion, the ignition delay becomes longer in advanced combustion modes. The longer ignition delay usually results in the fuel injection ending earlier than ignition. Therefore, the spray propagation after end-of-injection (EOI) plays a significant role in diesel combustion process, and it is needed to estimate the spray evolution and mixture formation after EOI. For this purpose, a simple and analytical diesel spray model including the spray evolution after the EOI is developed in this study. To develop the model, the theoretical analysis on the decelerating process of the turbulent jet tip is performed based on the integral momentum flux and mass flow rate of the injected fluid over the cross-sectional area at the jet tip. It is observed that the decrease of mass flow rate of the injected fluid over the tip cross-sectional area causes reduction of the momentum flux over the tip cross-sectional area and the turbulent jet tip decelerating. Then the mass flow rate of injected fluid over the tip cross-sectional area is formulated, furthermore the analytical equation of the turbulent jet tip penetration during decelerating state is derived, and the correctness of the developed analytical equation has been proved theoretically. Finally, the calculation is extended to diesel spray penetration, and the calculated results are validated against the one-dimensional discrete model and the experimental data from Engine Combustion Network (ECN) respectively. © 2017 Elsevier Ltd


Sun Y.-S.,Harbin Engineering University | Zhang Q.,Harbin No. 1 Tool Manufacture Corporation Ltd.
Neural Computing and Applications | Year: 2017

Based on the traditional boring bar, a boring bar with friction damper is proposed in the paper. Firstly, the frequency response under different pressures is computed primarily based on the theory, which shows that the proposed boring bar has a certain vibration reduction effect. Secondly, the finite element model of the boring bar is built, and the first 6-order modes are computed, whose results are compared with the experimental value. As a result, the virtual reality of the boring bar is achieved. They are consistent with each other, which show that the finite element model is reliable. Then, the experimental cutting process of the boring bar is researched, which is compared with the simulation model with good coincidence. It is found from the result that the cutting simulation model of the boring bar is effective. Later, based on the verified simulation model, the positive pressure between the friction vibrator and boring bar, cutting speed, feed rate, back cutting depth and other parameters are changed to study the vibration reduction effects of the boring bar with friction damper. PSO (particle swarm optimization)-BP (backpropagation) neural network is then used to optimize the cutting process of the boring bar, and the optimal cutting parameters can be obtained. Finally, these optimized parameters are applied in the boring bar, the vibration reduction effect of the boring bar is verified by means of experiments, and the corresponding result shows that the proposed optimization in this paper is feasible. We can obtain higher quality work piece when we use this boring bar in the actual engineering. © 2017 The Natural Computing Applications Forum


Gao H.,Harbin Engineering University | Du Y.,Harbin Engineering University | Liang Y.,Harbin Engineering University
International Conference on Digital Signal Processing, DSP | Year: 2017

In order to solve spectrum sensing problem, this paper proposes a cultural bacterial foraging algorithm (CBFA) based on bacterial foraging optimization algorithm (BFOA) and knowledge strategy of cultural algorithm. The proposed CBFA applies the knowledge strategy and new movement equations to bacterial foraging optimization, and thus has the advantages of low computational complexity and fast convergence. As a key step of CBFA, chemotactic movement is modelled as guiding cultural behaviour and thus may improve the capability of BFOA to find the optimum solution. Then we applied the proposed CBFA in cooperative spectrum sensing of cognitive radio (CR). We compare the performance of the proposed CBFA with classical BFOA, shuffled frog leaping algorithm (SFLA) and particle swarm optimization (PSO). The simulation results show that CBFA has a better searching speed and an obvious improvement in accuracy. © 2016 IEEE.


Wang Y.,Harbin Engineering University | Li Y.,Harbin Engineering University
International Conference on Digital Signal Processing, DSP | Year: 2017

A reweighted l1-norm penalized set-membership normalized least mean square (RL1SM-NLMS) algorithm is proposed for sparse system identification in this paper. The proposed RL1SM-NLMS algorithm is realized by incorporating a reweighted l1-norm constraint into the cost function of the traditional SM-NLMS algorithm to obtain a desired zero attractor term which is used for promoting the convergence for identifying the sparse systems. RL1SM-NLMS algorithm can speed up the convergence and provide a low estimation error floor by means of the zero attractor which is an additional shrinkage in its update equation. The proposed RL1SM-NLMS algorithm is mathematically given and its estimation performance is discussed by using computer simulation in detail. The simulation results obtained from different sparsity level and a echo channel confirm that the proposed RL1SM-NLMS algorithm is effective and robust for sparse system identification in comparison with the existing NLMS, SM-NLMS, ZA-NLMS, ZASM-NLMS and RZASM-NLMS algorithms. © 2016 IEEE.


Tian Y.,Harbin Engineering University | Li Y.,Harbin Engineering University | Ye F.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

Multimodal medical image fusion is an indispensable branch in the field of image fusion. In order to obtain a more complete and more reliable medical image, this paper presents a novel approach for multimodal medical image fusion using an improved pulse-coupled neural network (IPCNN) in nonsubsampled contourlet transform (NSCT) domain. First, the image is decomposed into sub-bands with different scales and different directions by NSP and NSDFB. Next, local area singular value is introduced to determine the structural information factor which will be the linking strength parameter of PCNN. After the fire process we can get the fire mapping images that can reflect the characteristics of single pixel and its neighborhood. Then, we extract the objects with salient features of the fire mapping images by compare-selection operator. Finally, we construct the fused image by inverse NSCT. Our proposed algorithm in multimodal medical image fusion is proved to perform better in robustness and reliability over the existing methods, meeting the requirement of human vision. © 2016 IEEE.


Chen J.,Harbin Engineering University | Ye F.,Harbin Engineering University | Li Y.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

In the field of rotary machinery fault diagnosis, the diversity and complexity of fault signals cause some uncertainty to fault diagnosis system. Aiming to obtain accurate diagnosis results, we propose a robust approach based on weighted entropy fusion and modified DS theory. The novel algorithm is realized by three steps. Firstly, we present a weighted entropy fusion method to combine four different features of fault signals. Then, we utilize DS theory to synthesize these fault signals from different measurement periods and different combination rules. And finally, a comprehensive decision-making method is applied to export precise fault identification. Simulation results and analyses demonstrate that the neoteric approach can not only get correct and effective fault characteristics under noise environment and limit-precision sensors, but also obtain accurate fault identification. Thus, this paper achieves the goal of safe operation of rotary machinery, which has great application value. © 2016 IEEE.


Zhao C.,Harbin Engineering University | Zhang H.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

The intention for fusion of low-spatial-resolution hyperspectral image (HSI) and high-spatial-resolution multi-spectral image (MSI) is to obtain a high-resolution image in both spectral and spatial domains, which is more suitable for object identification and precise positioning. A novel fusion algorithm for HSI and MSI is proposed in this paper to obtain a better spectral preserving performance. The method commences by endmembers extraction to extract the pure object spectra in HSI, then the abundances of these objects obtained by spectral unmixing are used to classify the pixels in MSI and determine which object these pixels belong to. Once the endmembers extraction and spectral unmixing results are obtained, a fused HSI with almost no distortion in spectra will be reconstructed by assigning the pure object spectra to pixels of MSI. The experimental results demonstrate that the proposed algorithm provides an effective way for fusion of HSI and MSI and avoids the spectral distortion to the most extent. © 2016 IEEE.


Zhang X.,Harbin Engineering University | Chen J.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

An approach was developed using maximum eigenvalue principal components analysis(PCA) neural network for direct sequence spread spectrum (DSSS) signals to reconstruct the pseudo noise(PN) sequence blindly in low SNR conditions. Firstly, the received signals were divided into column vectors to form an observation matrix according to a temporal window, whose duration is one period of PN sequence. Then, the autocorrelation matrix is obtained from the observation matrix of the signals. At last, we choose the neural network to find out the maximum eigenvalue of the autocorrelation matrix and use the corresponding eigenvector to reconstruct the PN sequence. This method can reconstruct the PN sequence accurately in the asynchronous condition without phase ambiguity. Simulation results show that the proposed algorithm performs well at low signal to noise ratios(SNR) in non-cooperation communication system. The disadvantages of the traditional neural network such as the sensitive to noise are improved. © 2016 IEEE.


Nie W.,Harbin Engineering University | Lv W.,A+ Network | Li Y.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

A new method to extract fetal electrocardiogram (FECG) signal from the mixed ECG signals is presented by introducing time-correlation to traditional independent component analysis (ICA). FECG signal extraction is a hot research topic because the FECG signal reflects the heart situation of the fetus and provides the basis of early diagnosis. In this paper, an objective function based on time-correlation and non-Gaussianity described in ICA is proposed. Maximizing the objective function, we present a fixed-point blind source extraction (BSE) algorithm. Simulation experiments of some typical data indicate the availability of the proposed algorithm. What's more, the proposed algorithm owns better performance than the comparison algorithms. © 2016 IEEE.


Jiang Y.,Harbin Engineering University | Tong Q.,Harbin Engineering University
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

Compressed Sensing(CS) is a novel signal processing technique. CS indicates that a sparse signal can be reconstructed from fewer measurements obtained by lower sampling frequency than Nyquist sampling. In this paper, we use the CS technique to compress and recover the infrared image. A central problem in CS is the construction of the measurement matrix. While the random measurement matrix has been studied intensively, it is hard to implement. Hence, we introduced a simple deterministic measurement matrix for infrared rosette scan sub-imaging system. The simulation results show that the proposed measurement matrices can compress and recover the infrared image. Furthermore, the proposed measurement matrices have the lower computational complexity. © 2016 IEEE.


Zhuang N.,Harbin Engineering University | Tan S.,Harbin Engineering University | Yuan H.,Harbin Engineering University | Yang B.,Harbin Engineering University
International Journal of Heat and Fluid Flow | Year: 2017

Plate-type nuclear reactor fuel is currently getting increasing attentions as it features excellent heat transfer ability and compact structure. To gain an insight into the influences of channel size and pulsatile parameters on flow resistance characteristics, steady and pulsatile turbulent experimental investigation were performed. Three channels with varying height were used. The covered ranges of time-averaged Re Reta = (0.5–2) ×104, dimensionless frequency sqrtω’ = 0.3–3.2, and pulsatile velocity amplitude Av = 0.04–0.93. A normalized parameter, friction factor ratio C =λta/λta, was proposed to denote the effects of flow fluctuation on time-averaged friction factor, where λta and λta are time-averaged and steady friction factor. The results show that in channel I (40 × 2 mm2), the time-averaged friction factor is remarkably larger than the steady values in the ranges of 1.5


Sun M.,Harbin Engineering University | Wang Z.,Harbin Engineering University | Yang B.,East China University of Science and Technology | Sun X.,Harbin Engineering University
Composite Structures | Year: 2017

In this paper, the impact response of unidirectional cross-ply GF/epoxy laminates with different shape memory alloys (SMAs) positions was investigated. According to vacuum assisted resin injection (VARI) process, we manufactured the laminates without SMAs, the laminates with one layer of SMAs were inserted in 1/8 thickness, in 1/2 thickness, in 14/16 thickness, and in 15/16 thickness of specimen, respectively, the laminates with two layers of SMAs were inserted in the 15/16 and 14/16 thickness, in 15/16 and 1/2 thickness, in 15/16 and 1/8 thickness, in 14/16 and 1/2 thickness, in 14/16 and 1/8 thickness, and in 1/2 and 1/8 thickness of specimen, respectively. The low-velocity impact experiment was performed by Dynatup 9250HV Drop Weight Impact Testing Machine under the impact energy of 28 J to analyze the impact response, and the impact parameters such as contact force (F), displacement (D) and energy (E) of the laminates were obtained. To further observe and analyze the impact damage morphology, we also adopted visual inspection and scanning electron microscope (SEM) technology. The experimental results showed that impact performance of laminates improved by embedding SMAs. By contrast, the impact performance of the laminates with two layers of SMAs was optimum. © 2017 Elsevier Ltd


Qian H.,Harbin Engineering University | Qiu Z.,Harbin Engineering University | Wu Y.,Harbin Engineering University
Aerospace Science and Technology | Year: 2017

In this paper, the robust filtering problem is investigated for nonlinear stochastic systems with random sensor delays, packet dropouts and correlated noises. The stochastic multiplicative noises which enter into both state equation and measurement equation are modeled as random variables with bounded variance, and a Bernoulli distributed random sequence is introduced to describe the random delays and packet dropouts. Then, the system is converted to the stochastic parameterized one through introducing a group of new variables. Moreover, the two-step prediction framework is employed to achieve the goal of noise decoupling. The objective of the addressed estimation problem is to design a filter, such that in the presence of random delays, packet dropouts, multiplicative noises and correlated noises, the upper bounds for the prediction error and estimation error covariance can be guaranteed. Subsequently, the upper bounds are minimized by designing the optimal prediction gain and filter gain. Finally, the attitude estimation example is used to demonstrate the effectiveness of the proposed robust extended Kalman filter. © 2017 Elsevier Masson SAS


Bai X.,Jiangsu University of Science and Technology | Xu W.,Harbin Engineering University | Ren H.,Harbin Engineering University | Li J.,Shandong Academy of Sciences
Ocean Engineering | Year: 2017

Load carrying capacity is of importance in the evaluation of the stability of submarine pressure shell structure. During the buckling process of cylindrical shell under hydrostatic pressure, the total potential energy of ring-stiffened cylindrical shell can be divided into constant component, linear component and square nonlinear component. Based on the derivations of buckling loads of smooth cylindrical shell and ring-stiffened cylindrical shell, the reduced stiffness method (RSM) is applied to assess the role of different stiffness reductions in the evaluation of stable load carrying capacity of cylindrical shell. This study shows: (1) the circumferential membrane stiffness is influence the stability of cylindrical shell largest; (2) the ring ribs have a significant effect on the overall stability of ring-stiffened cylindrical shells under hydrostatic pressure; (3) the circumferential buckling wave number of ring-stiffened cylindrical shell may not depend on the membrane stiffness reduction of shell, but it increases with the bending stiffness reduction of ring ribs. © 2017 Elsevier Ltd


Sun Y.,Harbin Engineering University | Xue R.,Harbin Engineering University | Zhao D.,Harbin Engineering University
Aerospace Science and Technology | Year: 2017

The number of satellite navigation signals in space grows dramatically as the number of global and regional navigation satellites constant increases. This phenomenon further aggravates an already crowded radio spectrum in-band and increases out-of-band (OOB) emissions. One feasible solution to the issue of signal compatibility is to design a spectrum-efficient modulation signal that has better navigation performance and backward compatibility with adjacent signals and services in operation. In this study, a time domain raised cosine (TDRC) pulse is introduced as an alternative waveform. A binary coded symbol (BCS) modulation family based on TDRC pulse called TDRC-BCS is also proposed as a candidate for future global navigation satellite system (GNSS). An extensive study on the multipath model analysis approach is also provided. The proposed modulation and existing modulations are then comprehensively evaluated. Theoretical analysis and simulation results show that TDRC-BCS signals offer superior navigation performance compared with existing modulations in terms of code tracking accuracy, multipath mitigation capacity, while maintaining comparable or better anti-jamming performance. These signals can also attain higher spectral efficiency and better backward compatibility with the existing GNSS signals. The proposed modulation scheme provides additional degrees of freedom for GNSS signal design. © 2017 Elsevier Masson SAS


Bi X.,Harbin Engineering University | Diao P.,Harbin Engineering University
Journal of Harbin Institute of Technology (New Series) | Year: 2016

Coverage control for each sensor is based on a 2D directional sensing model in directional sensor networks conventionally. But the 2D model cannot accurately characterize the real environment. In order to solve this problem, a new 3D directional sensor model and coverage enhancement algorithm is proposed. We can adjust the pitch angle and deviation angle to enhance the coverage rate. And the coverage enhancement algorithm is based on an improved gravitational search algorithm. In this paper the two improved strategies of GSA are directional mutation strategy and individual evolution strategy. A set of simulations show that our coverage enhancement algorithm has a good performance to improve the coverage rate of the wireless directional sensor network on different number of nodes, different virtual angles and different sensing radius. © 2016, The Editorial Department of Journal of Harbin Institute of Technology. All right reserved.


Liu D.,Dalian Nationalities University | Wang L.,Harbin Engineering University | Benediktsson J.A.,University of Iceland
International Journal of Remote Sensing | Year: 2017

Data visualization can accelerate data processing so that enormous quantities of data can be utilized effectively. Visualization of data can achieve image communication between people and data as well as between people to help observers get information hidden in data, providing a tool for discovery and understanding of scientific law. To solve the problem of multi-image and multi-modality image display in the field of remote sensing, an interactive colour visualization method for hyperspectral imagery (HSI) is proposed in this article. This method visualizes complex information of original HSI data through different fusion results of multiple images in a colour space, which is under the interactive control of the observers. By gradually determining predetermined points, observers can obtain a relatively satisfying image blending mode, output an image with clearer interested target, and obtain the corresponding mixing coefficient of images. The proposed method can also solve the problem that traditional visualization methods only display information from three bands in one image, and conduct information mining in HSI with a certain purpose based on the demands of users. In addition, this approach is also applicable for visualization of other types of multi-modal imagery. © 2017 Informa UK Limited, trading as Taylor & Francis Group.


Gao X.,Harbin Engineering University | Sun Y.,Harbin Engineering University | Zhu C.,Harbin Engineering University | Li C.,Harbin Engineering University | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2017

Increasing demands for detection of toxic gases in ambient atmosphere have attracted much attention to design and fabricate gas sensors with high sensitivity, good selectivity and low operating temperature. Herein, porous ZnFe2O4nanosheets (NSs) have been successfully synthesized using graphene sheets as hard templates. The as-fabricated ZnFe2O4NSs are composed of small particles with a diameter of approximately 10–20 nm and the pore size in the NSs is in range of 5–50 nm. In comparison with the Fe2O3NSs, ZnO NSs and ZnFe2O4nanoparticles (NPs), the gas sensors based on ZnFe2O4NSs exhibit superior H2S sensing performance, including high sensor response at a low working temperature (85 °C), relatively fast response and recovery times, and good selectivity. Furthermore, the sensors based on ZnFe2O4NSs show good repeatability and long-term stability. Our results demonstrate that the porous ZnFe2O4NSs are very promising for the fabrication of high-performance H2S gas sensors. The work highlights the possibility to develop a novel high performance gas sensor for practical applications. © 2017 Elsevier B.V.


Wang L.,Harbin Engineering University | Wang L.,Harbin University of Science and Technology | Sheng Y.,Harbin University of Science and Technology
Electronics Letters | Year: 2017

Due to the edge-preserving ability, the bilateral filter is considered as the fundamental tool in computer vision and computer graphics. However, its computational complexity has a close connection with the size of the box window. This drawback leads that the bilateral filter is inappropriate for the computational insensitive application. One way to accelerate the bilateral filter is to approximate the Gaussian range kernel by trigonometric functions and synthesise final results from a set of filtering results of fast convolutions. A novel approximation that can be applied to any range kernel is proposed. Specifically, first the Z transformation of the range kernel is obtained, then approximate the Z transformation of the range kernel using the Padé Approximation. Finally, inverse the transformation of the Padé approximation and obtain an exponential sum to approximate original range kernel, where the coefficients of the exponential basis are computed by solving a set of linear equations. Experiments show the method achieves state-of-the-art results in terms of accuracy and speed. © The Institution of Engineering and Technology 2017.


Wang L.,Harbin Engineering University | Sheng Y.,Harbin University of Science and Technology
Electronics Letters | Year: 2017

It has been demonstrated that the bilateral filter can be computed using a series of fast convolutions by approximating its Gaussian range kernel using trigonometric functions. A novel approximation that can be applied to any range kernel is proposed. Specifically speaking, an exponential sum is exploited to approximate the range kernel of the bilateral filter, where the coefficients of the exponential basis are computed by solving a set of linear equations. The major advantage of the method is that the tradeoff between the run-time and the filtering accuracy can be controlled by the cardinality of the exponential basis. Experiments show that the method achieves state-of-the-art results in terms of accuracy and speed. © 2017 The Institution of Engineering and Technology.


Sun Y.,Harbin Engineering University | Wang X.,Harbin Engineering University
Applied Computational Electromagnetics Society Journal | Year: 2017

Since the parameters of transmission line can affect the signal integrity and electromagnetic compatibility directly in high frequency circuit, and there is lack of researches in the field of solving the inductance parameter of nonuniform transmission line in anisotropic dielectric, a novel method has been proposed in this paper to solve this problem. The new method uses filament division to establish the dispersion model of nonuniform transmission line, and formulates the filament division principle based on Biot-Savart Law and skin effect. Then it develops the Ampere loop integral dyadic equations and the closed circuit dyadic impedance matrix equation with direction factor in frequency domain based on electromagnetic quasi-static (EMQS). To obtain the corresponding magnetic field direction factor, the relative position of filaments in geometric space is analyzed. Finally, the inductance parameters are obtained by the impedance matrix equation. The correctness of proposed method is verified by applying to uniform transmission line model. Then the new method is applied to the calculation of two nonuniform transmission line models which filled in free space and anisotropic dielectric respectively. The inductance parameters and frequency dependency solved by different methods are compared, showing accuracy and validity of the proposed method. Besides, the new method can be applied to various transmission line structures and different anisotropic dielectric. © ACES.


Ren H.-L.,Harbin Engineering University | Tian B.,Harbin Engineering University | Zhong Q.,Harbin Engineering University
Chuan Bo Li Xue/Journal of Ship Mechanics | Year: 2017

The wave loads characteristic of trimaran's main hull and cross structure is a great concern to ship structure designers, but comprehensive model tests are researched little in China currently. In this work, a trimaran's segmented model test was carried out in a towing tank and a square tank, the design principle of segmented model was introduced in detail, and different segmented models were designed for measuring longitudinal loads and transverse loads. According to analysis of the experimental values and comparison with the results of theoretical calculation, the nonlinear method of roll motion prediction was improved, and the wave loads characteristics of midship transverse section and cross structure longisection were reserached. Finally, some conclusions were obtained, which can be the basis for the design loads of this trimaran to ship structure designers. © 2017, Editorial Board of Journal of Ship Mechanics. All right reserved.


Wang Y.,Harbin Engineering University | Cao X.,Harbin Engineering University
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2017

Compared with conservative accident analysis method, best estimate plus uncertainty (BEPU) accident analysis method can gain realistic analysis results and safety margins, and improve the nuclear power plant economy and flexibility of operation with the reasonable security assurance. The rod ejection accident (REA) analysis models under the condition of hot full power (HFP) and hot zero power (HZP) were established by using the best estimate code RELAP5-3D according to the design features of CNP600. The dominant phenomena and processes were identified through REA phenomena identification and ranking table (PIRT), and the important input parameters which have significant impacts on the key safety parameters were selected. The DAKOTA code was used to generate the samples of the important uncertainty input parameters by taking the Latin hypercube sampling (LHS) approach and the one sided tolerance upper limits of the key safety parameters were calculated through non-parametric method. In both cases the results obtained show that the maximum average fuel pellet enthalpy, peak fuel pellet temperature, peak cladding temperature, peak system pressure during accident transient meet the REA acceptance criteria. In both cases the one sided tolerance upper limits of peak nuclear power obtained by the non-parametric method are reasonable, and the one sided tolerance upper limits of maximum average fuel enthalpy obtained have considerable safety margins compared with the traditional REA conservative analysis values. © 2017, Editorial Office of High Power Laser and Particle Beams. All right reserved.


Yang S.,Harbin Engineering University
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2017

In this paper, the received signal intensity, noise intensity of isotropic ambient noise, total self-noise, and mutual scattering effect caused by the incident wave of a multi-pole transducer were analyzed. The potential of the applicability of multi-pole-forming was deduced by the value of SNR. © 2017, Editorial Department of Journal of HEU. All right reserved.


He Z.,Harbin Engineering University | Sun X.-Y.,Harbin Engineering University | Gu X.,Harbin Engineering University
Ceramics International | Year: 2017

SrTiO3:Er3+ nanofibers were fabricated by the electrospinning process. The phase, microstructure, Doxorubicin loading and release properties, as well as upconversion emission of the fabricated SrTiO3:Er3+ nanofibers were investigated. The X-ray diffraction patterns indicate that the SrTiO3:Er3+ nanofibers have the pure cubic phase. The images of scanning electron microscopy and transmission electron microscopy demonstrate that nanofibers with a porous structure have been obtained. The SrTiO3:Er3+ nanofibers can be used in drug delivery system, which is confirmed by the Fourier transform infrared spectra, results of Barrett–Emmett–Teller measurements and thermogravimetry. Under 808 nm light irradiation, the release process of Doxorubicin in SrTiO3:Er3+ nanofiber shows close relation with the pH value. An acidic condition increases the solubility of the Doxorubicin for the protonated daunosamine group, which accelerates and improves the release of Doxorubicin in SrTiO3:Er3+ nanofibers. In addition, the degree of Doxorubicin release can be manifested by the changing intensity of upconversion emission. © 2017 Elsevier Ltd and Techna Group S.r.l.


Lu Y.,Harbin Engineering University | Olsen D.B.,Colorado State University
Journal of Engineering for Gas Turbines and Power | Year: 2017

Variable valve timing technologies for internal combustion engines are used to improve power, torque, and increase fuel efficiency. Details of a new solution are presented in this paper for optimizing valve motions of a full variable valve actuation (FVVA) system. The optimization is conducted at different speeds by varying full variable valve motion (variable exhaust open angle, intake close angle, velocity of opening and closing, overlap, dwell duration, and lift) parameters simultaneously; the final optimized valve motions of CY4102 diesel engine are given. The CY4102 diesel engine with standard cam drives is used in large quantities in Asia. An optimized electrohydraulic actuation motion used for the FVVA system is presented. The electrohydraulic actuation and optimized valve motions were applied to the CY4102 diesel engine and modeled using gt-power engine simulation software. Advantages in terms of volumetric efficiency, maximum power, brake efficiency, and fuel consumption are compared with baseline results. Simulation results show that brake power is improved between 12.8% and 19.5% and torque is improved by 10%. Brake thermal efficiency and volumetric efficiency also show improvement. Modeling and simulation results show significant advantages of the full variable valve motion over standard cam drives. Copyright © 2017 by ASME.


Zhao C.,Harbin Engineering University | Deng W.,Harbin Engineering University | Yao X.,Harbin Engineering University
Guangxue Xuebao/Acta Optica Sinica | Year: 2017

Real-time processing can reduce the pressure of data storage and downlink transmission caused by the ever-expending hyperspectral dataset, which has received more and more attention in hyperspectral anomaly detection. Since acquiring data with pushbroom has become main stream for hyperspectral imaging sensors, a real-time anomaly target detection method is proposed based on the framework of progressive line processing. In order to make sure the causality of real-time processing, the local causal window model is introduced into the Reed-Xiaoli anomaly detection algorithm, and the sliding local causal window is used to detect anomaly targets. In terms of the high computational complexity caused by the inversion of matrix, the recursive principle of the Kalman filter and the Woodbury's lemma are employed to update the status information of current data through iterating data status information at the previous moment, which avoids the inversion of large matrix. The simulated and real hyperspectral data are adopted for the experiment. The results show that under the premise of maintaining the detection accuracy, the proposed real-time algorithm improves the processing efficiency significantly compared with the original algorithm. © 2017, Chinese Lasers Press. All right reserved.


Huo Y.,Harbin Engineering University | Chow W.K.,Hong Kong Polytechnic University | Chow C.L.,City University of Hong Kong
Advances in Space Research | Year: 2017

Generation and characteristics of internal fire whirl (IFW) in a shaft model under microgravity are studied using Computational Fluid Dynamics (CFD). The shaft model has two diagonally opposite corner slits with an open roof and a 10-cm diameter heptane pool fire inside. Acceleration due to gravity is varied from normal value of g to 0.0125. g. Numerical simulation indicates that even under low gravity of 0.0125. g, circular air motion would still bring fuel to a high level to give a larger flame height in the shaft model, compared with that in free space under the same gravity environment, the ratio in flame height being about 1.5 except at very low gravity value. For IFW generated in the shaft model, the heat release rate, the maximum tangential velocity and the maximum axial velocity decrease slowly as gravity decreases when gravity is above 0.1. g. Below 0.1. g, these quantities decrease rapidly as gravity decreases. Reduction in gravity also changes the flame shape of IFW. © 2017 COSPAR.


Fu Y.-W.,Harbin Engineering University | Liao Y.-L.,Harbin Engineering University
CGNCC 2016 - 2016 IEEE Chinese Guidance, Navigation and Control Conference | Year: 2016

The micro unmanned surface vehicles (MTJSV) can be disturbed by ocean environment easily when moving and is usually equipped with low precision sensors. Thus, the data collected by sensors has the disadvantage of high noise, low precision and inadequate information. So it is hard to be used in motion control system directly. To solve above problems, an improved unscented Kalman filter (ITJKF) algorithm is proposed and applied to heading control system of MTJSV. The method optimizes unscented Kalman filter (UKF) and enhances the capability of anti-disturbance under high-noise condition. This paper is based on Charlie MTJSV and carries out the simulation and contrast experiment on ITJKF, UKF and extended Kalman filter (EKF). The results indicate that compared with UKF and EKF, IUKF has the advantage of strong ability of anti-disturbance, high precision and good convergence property. The algorithm eliminates the adverse effect caused by environmental noise and model vibration effectively and also estimates real-time yaw rate, yaw acceleration and create the condition for heading control. Therefore, the accuracy and stability of the control system are improved considerably. © 2016 IEEE.


Yang Y.-Z.,Harbin Engineering University | Gao Y.,Harbin Engineering University
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2016

Cold flow numerical simulation of different obstacle's height and different mass flow injection was developed to study the effect of vortex impact frequency and intensity on pressure oscillations magnitude-frequency characteristic in chamber. The results show that the pressure oscillation amplitude in chamber and at the location of impact has the same order of magnitude. The impacts only strengthen acoustic field when the impact strength is not strong, but with the increase of impact strength, the pressure oscillation induced by impact gradually covers acoustic field. The pressure oscillations magnitude-frequency characteristic in chamber is mainly decided by the frequency and strength of vortex impacting, which usually presents low frequency, nonlinear and non-acoustic. © 2016, Editorial Dept. of JSRT. All right reserved.


Zhang Y.,Harbin Engineering University | Tang X.,Harbin Engineering University | Liu Z.,Harbin Engineering University
Optics InfoBase Conference Papers | Year: 2016

We propose and demonstrate a novel structure of single optical fiber tweezers with high trapping efficiency based on bessel-like beams, trapping of polystyrene with deep micrometerscale and submicrometer-scale with larger force and high capture efficiency. © OSA 2016.


Liu Z.,Harbin Engineering University | Tang X.,Harbin Engineering University | Zhang Y.,Harbin Engineering University
Optics InfoBase Conference Papers | Year: 2016

We propose and demonstrate a novel structure of non-contact single optical fiber multioptical tweezers based on Bessel-like beams, simplified the structure of multi-optical tweezers, achieve the non-contact capture of particles at different axial positions. © OSA 2016.


Li Z.,Queen's University | Yuan Y.,Zhejiang University | Jing X.,Harbin Engineering University
Journal of Alloys and Compounds | Year: 2017

Various strategies for the elimination of inherent defects from plasma electrolytic oxidation (PEO) coatings are being developed for practical applications. In this regard, two types of composite coatings were introduced via PEO treatment followed by chemical conversion approach on a magnesium-lithium alloy (Mg-Li alloy). Detailed morphologies and compositions of the composite coatings were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and thin-film X-ray diffraction (TF-XRD). Barrier properties of the composite coatings were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results demonstrate that this two-step approach improves the anti-corrosion performance of the composite coatings for protection of the Mg-Li alloy. Specifically, the stannate composite coating exhibits enhanced corrosion resistance and impressive long-term stability relative to the composite coating prepared in cerium and lanthanum conversion solution. Our method allows the simple, efficient, and cost-effective fabrication of high-quality composite coatings based on a combined PEO and chemical conversion process on Mg-Li alloys, and therefore it holds great promise for a wide range of applications where corrosion resistance is vital. © 2017 Elsevier B.V.


Shi Y.,Harbin University of Science and Technology | Tang Y.,Harbin University of Science and Technology | Li S.,Harbin Engineering University
IET Control Theory and Applications | Year: 2017

In this study, the finite-time control problem is studied for discrete time-varying systems with randomly occurring non-linearity and missing measurements. The randomly occurring non-linearity is modelled according to a Bernoulli distributed white sequence with a known conditional probability. The missing measurements phenomenon is assumed to occur in a random way and the missing probabilities are time-varying with known upper and lower bounds. Two sufficient conditions are established for the existence of the state feedback and output feedback controllers, which guarantee the finite-time stochastic stability of the closed-loop systems. The recursive linear matrix inequality approach is employed to design the desired controller gains. A numerical example is provided to illustrate the effectiveness of the obtained results. © The Institution of Engineering and Technology 2017.


Pak C.,Harbin Engineering University | Pak C.,Korea University | Huang L.,Harbin Engineering University
Signal Processing | Year: 2017

This paper introduces a method of making a simple and effective chaotic system by using a difference of the output sequences of two same existing one-dimension (1D) chaotic maps. Simulations and performance evaluations show that the proposed system is able to produce a one-dimension (1D) chaotic system with better chaotic performances and larger chaotic ranges compared with the previous chaotic maps. To investigate its applications in image encryption, a novel encryption system of linear-nonlinear-linear structure based on total shuffling is proposed. The experiment demonstrated the accuracy of the encryption algorithm. Experiments and security analysis prove that the algorithm has an excellent performance in image encryption and various attacks. © 2017 Elsevier B.V.


Xu B.,Harbin Engineering University | Wang G.,Harbin Engineering University | Bai J.,Harbin Engineering University
Ocean Engineering | Year: 2017

High accuracy reference velocity is important for damping network of inertial navigation system, but complexity of underwater environment and movement of carrier bring high frequency and low frequency error into DVL velocity. The traditional damping network is difficult to inhibit high & low frequency error simultaneously. This paper proposes a method of damping network designed optimally based on the complementary filter: 1) DVL velocity error model is constructed, and the characteristic of velocity error in several typical motion state is analyzed; 2) Based on inertial measurement unit and DVL velocity, the designed principles of damping network are discussed, and amplitude-frequency characteristic of different damping network is analyzed; 3) Damping network is designed through the complementary filter that combines the good low frequency characteristic of lag-lead calibration network and high frequency characteristic of constant velocity feedback network. It has both excellent high frequency and low frequency characteristics. Software simulation and experimental results show that the proposed damping network not only eliminate high frequency noise component of inertial devices, but also effectively inhibit high & low frequency error of DVL reference velocity. © 2017 Elsevier Ltd


Xu G.D.,Harbin Engineering University | Xu W.H.,Harbin Engineering University | Dai J.,Harbin Engineering University
Applied Ocean Research | Year: 2017

The energy extraction performance of a flapping foil generator is studied through experiment and numerical simulation. A practical flapping foil generator has been proposed. The heave motion and the pitch motion of the foil are adjusted through a crankshaft-like structure. The heave and pitch motions of the foil are transferred to the rotational motion of the main shaft. A pair of gears is adopted to increase the pitch angle. A prototype with pitch amplitude θ0 = 60∘ has been built and the experiment is carried out in a tunnel. The overall performance of the mechanism has been analysed. Good agreement of numerical results and experiment data has been found. Further simulations with larger pitch amplitudes are carried out. It is found that higher efficiency can be achieved with larger pitch amplitude at medium frequency. © 2017 Elsevier Ltd


Hu Y.,Harbin Engineering University | Zhang S.,Harbin Engineering University | Chen J.,Harbin Engineering University
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

In this paper, a multi-objective slotting optimization problem of stereoscopic warehousing system based on different demand frequencies and the principle of shelf stability is studied. The objectives are to minimize the total routing with the weight of turnover rate of the goods, and the shelf center of gravity, at which a multi objective 0-1 integer programming model is established aimed. Dimensionless method and weighted sum method are first applied to transfer the multiple objective model to a single objective model formulation. The Hungarian method is then used to solve the problem and the solution has been proved to get optimal. Finally, a data test is provided to illustrate the effectiveness of the method. This study can provide theoretical and technical support for warehousing slotting optimization system.


Qi H.,Harbin Engineering University | Zhang X.M.,Harbin Engineering University
Journal of Mechanics | Year: 2017

With the aid of the Green's function method and complex function method, the scattering problem of SH-wave by a circular inclusion near the two symmetrically permeable interfacial cracks in the piezoelectric bi-material half -space is considered to obtain the steady state response. Firstly, by means of the image method, the essential function of Green's function is constructed, which satisfies the stress free and electric insulation conditions on the horizontal boundaries in a right-angle space including a circular inclusion and bearing a harmonic out-plane line source force on the vertical boundary. Secondly, the bi-material media is divided into two parts along the vertical boundary. According to continuity condition, the first kind of Fredholm integral equations containing undetermined anti-plane forces are established by “the conjunction method” and “the crack-division technology”, then the integral equations are reduced to the algebraic equations including finite items by effective truncation. Finally, the dynamic stress concentration factor around the edge of circular inclusion and dynamic stress intensity factor at the crack tip are calculated, then the influences of the frequency of incident wave, the length of crack, the position of the crack, the position of circular inclusion, etc. on the dynamic stress concentration factor and dynamic stress intensity factor are discussed. Copyright © The Society of Theoretical and Applied Mechanics 2017


Li W.,Harbin Engineering University | Yue C.,Harbin Engineering University | Elsherbeni A.,Colorado School of Mines
International Journal of Antennas and Propagation | Year: 2017

Numerical analysis methods are often employed to improve the efficiency of the design and application of the source-stirring reverberation chamber. However, the state of equilibrium of the field inside the chamber is hard to reach. In this paper, we present a fast simulation method, which is able to significantly decrease the simulation time of the source-stirring reverberation chamber. The mathematical model of this method is given in detail and home-made FDTD code is employed to conduct the simulations and optimizations as well. The results show that the implementation of the method can give us the accurate frequency response of the source-stirring chamber and make the simulation of source-stirring chamber more efficient. © 2017 Wenxing Li et al.


Wang G.,Harbin Engineering University | Li N.,Harbin Engineering University | Zhang Y.,Harbin Engineering University
Signal Processing | Year: 2017

In this paper, we propose a new diffusion strategy based distributed state estimation algorithm over sensor networks. In the proposed algorithm, every sensor only communicates with their neighboring sensors, and only intermediate estimation information is exchanged to avoid sharing raw measurements, which may be unavailable or inconvenient to be transmitted under some circumstances. Local estimations are obtained through a new method and the convex combination weights are obtained through covariance intersection (CI) technology. To further release the communication burden and energy consuming, one simplified algorithm is also given, where the local and final estimations are fused at a selected rate. We analyze the mean and convergence performances of proposed algorithms under some assumptions. Numerical simulations show that the first algorithm has better estimation accuracy when comparing with several existing diffusion based methods, and the latter simplified algorithm has good estimation accuracy but greatly reduced communication burden and energy consuming. © 2016


Sun Y.,Harbin Engineering University | Wang X.,Harbin Engineering University
ISAPE 2016 - Proceedings of the 11th International Symposium on Antennas, Propagation and EM Theory | Year: 2016

In this paper, a novel method using conformal technique of finite-difference method (FDM) is proposed to solve the distributed capacitance for microstrip lines. Instead of deriving the average dielectric constant ϵ, this method uses electric field numerical weights to process the inhomogeneous cells, and takes the discontinuous effects of both inhomogeneous Ampere cell and Faraday cell into account. The new method shows good agreement with the measurement and traditional methods. © 2016 IEEE.


Li Y.,Harbin Engineering University | Wang Y.,Harbin Engineering University | Yu K.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

In this paper, a single-band and dual-band circular polarized antenna is proposed by using stacked asymmetric-circular shaped slots and its performance is investigated in detail. The proposed circular polarized antenna is implemented by setting the positions of these asymmetric-circular shaped slots to render it suitable for dual-band and single-band applications. The proposed antenna has two radiation layers. The performance of the proposed antenna is numerically investigated in order to achieve a good circular polarization characteristic. The circular polarization function can be adjusted by changing the sizes and positions of these circular slots. Simulated results show that the designed antenna can provide circular polarized characteristics. © 2016 IEEE.


Jiao T.,Harbin Engineering University | Jiang T.,Harbin Engineering University | Li Y.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

A two-element low mutual coupling antenna array is designed by using alternating-direction S-shaped defected ground structures (ADS-DGSs). The proposed antenna array operates at 2.45GHz WLAN band, and it consists of two identical rectangle patch antennas and a pair of ADS-DGSs etching on the common ground plane. The performance of the proposed antenna is numerically investigated in order to achieve a high isolation. The mutual coupling of the antenna array is reduced by means of the ADS-SGS. Simulated results show that the design can provide a 30 dB mutual coupling reduction at the operating band. © 2016 IEEE.


Gao S.,Harbin Engineering University | Jiang T.,Harbin Engineering University | Hao S.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

In this paper, we simulate an electromagnetic model of sea surface under typical sea conditions based on the geometrical theory of diffraction. And an estimation method of effective scattering area is analyzed to meet the requirements of electromagnetic simulation of sea surface. To improve the computing efficiency, a method of simulation area extension for rough sea surface is presented and the effectiveness of the extension method is demonstrated. © 2016 IEEE.


Hao S.,Harbin Engineering University | Jiang T.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

In this paper, a novel UWB antenna with good characteristics for microwave imaging system is represented. The antenna is printed on an FR4 substrate of thickness 1.6 mm and permittivity 4.4. The antenna is fed by a CPW line which is designed for 50 Ohm characteristic impedance. The antenna structure is composed of a circular radiating element, a micro-strip transmission line and a defected ground structure which provides a wide band width. By tuning the parameters of the defected ground structure, the proposed UWB antenna can cover from 2.7GHz to 13.8GHz frequency with a VSWR less than 2 and return loss less than-10. It is promising in microwave imaging systems due to its wider bandwidth, better VSWR response, lower return loss and better surface current distribution for using in microwave image field. © 2016 IEEE.


Xu P.,Harbin Engineering University | Jiang T.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

In this paper, a new indoor location algorithm using RFID is proposed in order to improve the positioning accuracy. The new algorithm is based on VIRE. This new algorithm introduces the concept of assit virtual reference tags to generate a more accurate estimate, and makes each virtual tag own a more appropriate threshold. It is shown that the new algorithm improve the positioning accuracy compared with the conventional algorithm using RFID. The simulation results compared to the conventional algorithm-VIRE are presented. © 2016 IEEE.


Liu W.,Harbin Engineering University | Jiang T.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

A novel ultra-wideband (UWB) antenna with tri-band notched characteristics is proposed which based on complementary split ring resonator (CSRR) and slots structure. The tri-band notched characteristics are achieved by etching CSRR on radiating patch and slots on ground plane. The UWB antenna can work effectively in the frequency regions of 3.1GHz∼12.4GHz and realized characteristic of band-notched in frequency bands of 4.1∼4.9GHz, 6.9∼7.1GHz (RADIO and TELEVISION) 9.3∼10.4GHz (X band of Radar). The simulated results indicate that the presented antenna has good radiation, ultra-wideband characteristic and has a monopole-like radiation patterns in pass band. © 2016 IEEE.


Li Y.,Harbin Engineering University | Kong Y.,Harbin Engineering University | Yu K.,Harbin Engineering University
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

This paper proposes a compact dual band-notched UWB-MIMO antenna whose size is 26.5-30mm2. Two identical semicircle ring shaped monopole UWB antennas are designed and placed side by side. Two notched bands are realized by etching two L-shaped slots on the ground plane and inserting two 'anchor' shaped stubs into the radiating patch to suppress the WiMAX and WLAN band interferences. Simulated results show that two notch bands and wide bandwidth are achieved. Furthermore, the proposed UWB-MIMO antenna can provide a high isolation which is better than-19.74 dB in most of the UWB band. Also, gain and radiation patterns are given to verify the effectiveness of the designed UWB-MIMO antenna. © 2016 IEEE.


Zhang W.,Harbin Engineering University | Zhang J.,Harbin Engineering University | Zhang T.,Harbin Engineering University
Journal of Physics: Conference Series | Year: 2017

For the randomness and complexity of ocean wave, and the simulation of large-scale ocean requires a great amount of computation, but the computational efficiency is low, the real-time ability is poor, a fast method of wave simulation is proposed based on the observation and research results of oceanography, it takes advantage of the grid which combined with the technique of LOD and projection, and use the height map of ocean which is formd by retrieval of ocean wave spectrum and directional spectrum to compute with FFT, and it uses the height map to cyclic mapping for the grid on GPU which combined with the technique of LOD and projection to get the dynamic height data and simulation of ocean. The experimental results show that the method is vivid and it conforms with randomness and complexity of ocean wave, it effectively improves the simulation speed of the wave and satisfied with the real-time ability and fidelity in simulation system of ocean. © Published under licence by IOP Publishing Ltd.


Jian S.,Harbin Engineering University | Wen W.,Harbin Engineering University
Journal of Physics: Conference Series | Year: 2017

This paper analyzes the application of MATLAB in underwater image processing, the transmission characteristics of the underwater laser light signal and the kinds of underwater noise has been described, the common noise suppression algorithm: Wiener filter, median filter, average filter algorithm is brought out. Then the advantages and disadvantages of each algorithm in image sharpness and edge protection areas have been compared. A hybrid filter algorithm based on wavelet transform has been proposed which can be used for Color Image Denoising. At last the PSNR and NMSE of each algorithm has been given out, which compares the ability to de-noising. © Published under licence by IOP Publishing Ltd.


Wang M.,Harbin Institute of Technology | Zhang Y.,Harbin Engineering University
Nonlinear Analysis, Theory, Methods and Applications | Year: 2017

In Guo and Wu (2015) and Wu (2015), the authors studied a two-species competition-diffusion model with two free boundaries. These two free boundaries describing the spreading fronts of two competing species, respectively, may intersect each other as time evolves. The existence, uniqueness and long time behavior of global solution have been established. In this note we discuss the conditions for spreading and vanishing, and more accurate limits of (u,v) as t→∞ when spreading occurs. Some new results and simpler proofs will be provided. © 2017 Elsevier Ltd.


Yang L.,Harbin Engineering University | Zhang J.,Harbin Engineering University
Eurasip Journal on Wireless Communications and Networking | Year: 2017

As a new emerging technique, transfer learning enjoys the advantage of integrating the well-learnt knowledge from another related work to facilitate an improved learning result of one task. Most of the existing transfer learning methods are designed for long texts and short texts. However, the latter one distinguishes from the former one in terms of its sparse nature, noise words, syntactical structure, and colloquial terminologies used. A transfer learning algorithm called automatic transfer learning (AutoTL) is proposed for short text mining. By transferring knowledge automatically learnt from the online information, the proposed method enables training data to be selected automatically. Furthermore, it does not make any a priori assumption about probability distribution. Our experimental results on 20Newsgroups, Simulated Real Auto Aviation, and Reuter-21578 validate the higher performance of the proposed AutoTL over several state-of-of-the-art methods. © 2017, The Author(s).


Ning X.,Harbin Engineering University | Guo L.,Harbin Engineering University | Sha X.,Harbin Institute of Technology
International Conference on ICT Convergence | Year: 2012

Time delay is an important issue in signal processing. In this paper, we propose an approach to joint time delay and frequency offset estimation by parameters detection on the Fractional Fourier Transform (FRFT) domain with fractional correlation. We analyze the selection of transmitted signal, transform order and complexity of computation, after which simulation results are given for validation. © 2012 IEEE.


Zhong Y.,Harbin Engineering University | Chang S.,Harbin Engineering University | Dong G.,Harbin Engineering University
Microporous and Mesoporous Materials | Year: 2017

A double-walled Na2(TiO)SiO4 nanotube was prepared by an effective hydrothermal process with cetyltrimethyl ammonium bromide (CTAB) as an assistant. The precursor SiO2-TiO2 composite powder with diverse Si/Ti molar ratios was prepared by co-precipitation method using silica sol and titanyl sulfate as raw materials. Then it was added into the NaOH aqueous solution with CTAB for hydrothermal reaction. The Na2(TiO)SiO4 nanotubes were characterized by X-ray diffraction (XRD), thermogravimetric and differential scanning calorimeter (TG-DSC), transmission electron microscope (TEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (29Si-NMR), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and N2 adsorption-desorption. The results showed that the Na2(TiO)SiO4 nanotubes are of large specific surface area, double-wall and Q0 structure. The length of Na2(TiO)SiO4 nanotubes can be controlled by adjusting the Si/Ti molar ratios from 100 nm to several hundred nanometers. A possible formation mechanism of the novel double-walled Na2(TiO)SiO4 nanotubes was also proposed. © 2016 Elsevier Inc.


Yan X.,Harbin Engineering University | Fan G.,Harbin Engineering University | Sun Z.,Harbin Engineering University
Annals of Nuclear Energy | Year: 2017

Flow characteristics are relevant to the safe operation of natural circulation systems. Experimental research on flow characteristics in an open natural circulation loop was conducted. It was shown that flashing and geysering are the two fundamental phenomena influencing the flow characteristics; in addition, flashing and geysering interact reciprocally: geysering weakens the impact of flashing on the flow, while flashing can suppress geysering. Six circulation modes were identified based on the weight of flashing and geysering, as well as typical inlet flowrate curve and experimental observations. As the heating power varies, so do the weights of flashing and geysering, which result in variable flow behavior and the evolution of circulation modes. Based on the theoretical analysis and the calculation of average circulation flowrate by taking into account the effects of subcooling, flashing and heat dissipation, suggestions for the operating and improvement of the system were proposed. © 2017


Liu L.,Harbin Engineering University | Yang X.,Harbin Engineering University | Jing X.,Communication University of China
Applied Optics | Year: 2017

Multifractal analysis (MFA) based on generalized concepts of fractals has been applied to biological tissues composed of complex structures. In this paper, a new MFA methodology based on the neighborhood spatial correlation (NSC) is proposed for an extracting texture feature. NSC is used to extract spatial features, and the obtained spatial features are combined with spectral features of characteristic absorption peaks (CAPs) to promote more feature information. This spatial-spectral structure is used as a feature to differentiate cholesterol from Fourier transform infrared spectroscopy microscopic imaging of a rabbit artery by a support vector machine classifier. The dataset was collected between 4000 and 720 cm-1 on rabbit arteries as research objects. The experimental results show that the accuracy of the proposed spatial-spectral structure is higher than that of other multivariate analysis methods (PCA and 2DPCA). The NSC method, compared to the bottom interface method, new bottom interface method, variance method multi-weight method, and neighborhood spatial correlation method, could effectively reduce the influence of speckle noise, and the convergence rate of the weight factor q is not increased. © 2017 Optical Society of America.


Chen L.,Harbin Engineering University | Qiao Y.,Harbin Engineering University
2016 IEEE International Conference on Information and Automation, IEEE ICIA 2016 | Year: 2016

Dynamic texture segmentation is to partition a video (image sequence) comprising of different dynamic texture into disjointed regions with uniformity and consistency property. This paper introduces a Markov random field based dynamic texture segmentation algorithm using the inter-scale context. The method models the lab ENGLel field and the observed field with the Multi-level Logistic Model (MLL) and Gaussian Markov random field, respectively. For dynamic texture segmentation, we iteratively refine and update the initial segmentation result. Specially, we refine the segmentation results with the two-scale random field description from the coarsest scale to finest scale, and then update the segmentation with single scale random field description from the finest scale to coarsest scale. Finally, the lab ENGLel at the fine scale is the segmentation result. The experimental results demonstrate the effectiveness of the proposed algorithm. © 2016 IEEE.


Zhong Z.,Harbin Engineering University | Qin H.,Harbin Engineering University | Liu L.,Harbin Engineering University | Zhang Y.,Harbin Engineering University | Shan M.,Harbin Engineering University
Optics Express | Year: 2017

A novel approach for silhouette-free image encryption based on interference is proposed using discrete multiple-parameter fractional Fourier transform (DMPFrFT), which generalizes from fractional Fourier transform. An original image is firstly applied by chaotic pixel scrambling (CPS) and then encoded into the real part of a complex signal. Using interference principle, the complex signal generates three phase-only masks in DMPFrFT domain. The silhouette of the original image cannot be extracted using one or two of the three phase-only masks. The parameters of both CPS and DMPFrFT can also serve as encryption keys to extend the key space, which further enhance the level of cryptosystem security. Numerical simulations are demonstrated to show the feasibility and validity of this approach. © 2017 Optical Society of America.


Shi L.,Kagawa University | Guo S.,Harbin Engineering University | Guo S.,Kagawa University | Asaka K.,Japan National Institute of Advanced Industrial Science and Technology
IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM | Year: 2011

For applications such as pollution detection and video mapping in limited space, underwater microrobots are urgently demanded. To meet these purposes, we designed a novel microrobot with ionic polymer metal composite (IPMC) actuators. We carried out some experiments to evaluate its crawling speeds on the underwater floor. Then we proposed a new type of underwater microrobot using ten ionic polymer metal composite (IPMC) actuators as legs or fingers, which could implement walking, rotating, floating, and grasping motions. We developed a prototype of this underwater microrobot and carried out some experiments to evaluate its walking and floating speeds. We then analysed the walking mechanism of the microrobot and calculated its theoretical walking speed. © 2011 IEEE.


Song Z.,Kagawa University | Guo S.,Kagawa University | Guo S.,Harbin Engineering University
2011 IEEE International Conference on Mechatronics and Automation, ICMA 2011 | Year: 2011

Rehabilitation based on robot has been important researches field. In this paper, an exoskeleton device for upper limb has been developed, and it includes three active DoFs (Degree of Freedoms) and four passive DoFs. This device is used to assist performance for the impaired upper limb. Hemiplegic patients can move their intact upper limb by manipulating a haptic device (Phantom Premium) and their impaired upper limb can move synchronously, which is driven by the exoskeleton device. Different from general joystick, haptic device not only exert force to patients, but also can detect the movement of upper limb because of its 6 DoFs and enough work range. Therefore, the impaired upper limb can perform following the intact upper limb and patients can perform some rehabilitation by themselves. In this paper we focused on the motion detection of intact limb. Control on exoskeleton device was discussed in previous work. Also this system can be used in remote rehabilitation. © 2011 IEEE.


Gao B.,Kagawa University | Guo S.,Kagawa University | Guo S.,Harbin Engineering University
IEEE International Conference on Automation and Logistics, ICAL | Year: 2011

As the development of the ICPF (ionic conducting polymer films) actuator in MEMS, it has been one of the most interested materials due to its large bending deflection, high mechanical deformation, low excitation voltage, low density and manufacturing cost. In this paper, we will present the Cube Minimum Unit Model according to the hypothesis of considerable mechanical deformation principle of the ICPF actuator, and discuss the material relationships for ICPF actuator being recognized as a isotropic material, and show the equations of the forces, bending moment and transverse shear forces. We also give the electric field and stress analysis of the ICPF actuator based on the equivalent electrical circuit model and resolve the subject of output stress control based on the open-loop response. For the fish-like underwater microrobot, the ICPF actuated fish fin is an important mechanism, we will use ANSYS to give the dynamics analysis and improve the moving performance of the fish-like underwater microrobot by revising the shape of fish fin. © 2011 IEEE.


Zhao J.,National University of Singapore | Tao Z.-Y.,Harbin Engineering University
Journal of Sound and Vibration | Year: 2013

We investigate the nonBragg bandgap (NBBG) resulting from interference between two transverse guided wave modes in an axisymmetric duct with periodic walls. We find that the NBBG bandwidth is proportional to both the height and shape factor of the wall undulations. The shape factor is defined as the norm of the major Fourier component of the periodic wall profile. Varying the height directly tunes the bandwidth, while manipulating the wall profile results in a slight change in the shape factor, which leads to fine-tuning of the bandgap. We also find that for a fixed height, the NBBG width is related to the area under the curve for the product of the wall profile and a half-period sine or cosine function. We propose an area estimation method according to which a larger area results in a wider NBBG. A numerical example reveals that NBBG fine-tuning can be achieved by carefully varying the shape factor. The results will benefit the design of band structures, especially subtle modifications by selecting suitable wall undulations. © 2013 Elsevier Ltd.


Luo Y.,University of New South Wales | Wen J.,Shanghai University | Zhang J.,University of New South Wales | Zhang J.,Harbin Engineering University | And 2 more authors.
Optics Letters | Year: 2012

We report the first (to our knowledge) development of a Bi/Er/Al/P codoped germanosilica optical fiber showing ultrabroadband luminescence between 1000 and 1570 nm, covering O-, E-, S-, C-, and L-bands, when pumped by 532, 808, or 980 nm lasers. The fluorescence profiles are found highly pump wavelength dependent, closely associated with different combinations of excitations from both Bi centers and Er ions as active centers. With a proper selection of pump wavelength(s), this Bi/Er codoped fiber could be used as an ultrabroadband gain medium for ultrabroadband amplified spontaneous emission sources, fiber lasers, or amplifiers in telecommunications and in other fields. © 2012 Optical Society of America.


Shi L.,Kagawa University | Guo S.,Kagawa University | Guo S.,Harbin Engineering University | Asaka K.,Japan National Institute of Advanced Industrial Science and Technology
International Journal of Robotics and Automation | Year: 2012

In this paper, we introduce a new biomimetic underwater microrobot with a shape memory alloy (SMA). It moves like a jellyfish while floating or sinking and has two pectoral fins to implement a swimming motion like that of a butterfly. To achieve a larger volume change, the body was designed as a triangular prism. We then modelled the characteristics of the body and calculated its floating speed. Moreover, we used two pectoral fins to push water horizontally and analysed the resulting swimming motion. We measured the response time of the SMA actuator with different driving voltages and calculated its theoretical swimming speed. Finally, we developed a prototype hybrid biomimetic microrobot and evaluated floating and swimming speeds experimentally. The values obtained from the floating and swimming experiments were in close agreement with the theoretical values. Also, the experimental floating performance of the new microrobot was better than that of the earlier two-ring units. Its floating speed reached a maximum of 10.2 mm/s, and it attained a maximum swimming speed of 57.2 mm/s at 24 V, a frequency of 0.4 Hz, and a duty cycle of 35%. Additionally, it exhibited better flexibility, balance, and load capacity than its predecessors.


Guo S.,Kagawa University | Guo S.,Harbin Engineering University | Shi L.,Kagawa University | Xiao N.,Kagawa University | Asaka K.,Japan National Institute of Advanced Industrial Science and Technology
Robotics and Autonomous Systems | Year: 2012

Underwater microrobots are in urgent demand for applications such as pollution detection and video mapping in limited space. Compact structure, multi-functionality, and flexibility are normally considered incompatible characteristics for underwater microrobots. Nevertheless, to accomplish our objectives, we designed a novel inchworm-inspired biomimetic locomotion prototype with ionic polymer metal composite (IPMC) actuators, and conducted experiments to evaluate its crawling speed on a flat underwater surface. Based on this type of biomimetic locomotion, we introduced a new type of underwater microrobot, using ten IPMC actuators as legs or fingers to implement walking, rotating, floating, and grasping motions. We analysed the walking mechanism of the microrobot and calculated its theoretical walking speed. We then constructed a prototype of the microrobot, and carried out a series of experiments to evaluate its walking and floating speeds. Diving/surfacing experiments were also performed by electrolysing the water around the surfaces of the actuators. The microrobot used six of its actuators to grasp small objects while walking or floating. To implement closed-loop control, we employed three proximity sensors on the microrobot to detect an object or avoid an obstacle while walking. © 2012 Elsevier Ltd. All rights reserved.


Lei H.,Harbin Engineering University | Lei H.,University of Sydney | Wang Z.,Harbin Engineering University | Tong L.,University of Sydney | And 2 more authors.
Composite Structures | Year: 2013

This paper presents an experimental and numerical investigation into the macroscopic mechanical behavior of shape memory alloy hybrid composites (SMAHCs) subjected to quasi-static loading taking into account of weak interface effect and damage evolution. SMA fiber reinforced hybrid laminates were fabricated by vacuum assisted resin injection (VARI). Scanning electron microscopy was used to evaluate the quality of SMA-matrix interface. Uniaxial tensile tests were performed to study the effects of weak interface on the effective modulus of hybrid composite. Failure morphology was discussed based on the observation using digital HF microscope. Owing to the embedding of SMA fiber, the material exhibited a bilinear mechanical behavior, and the overall stiffness of composite at the second stage was lower on average 32.7% than that of the first stage. Ultimate strength was improved by 3.4% for the three-SMA-fiber composite, and rupture elongation was slightly decreased (∼0.1%). A script program was developed to generate the hybrid composite model by using ANSYS Parameter Design Language (APDL). Uniaxial tensile test was simulated using finite element method to study the macroscopic behavior of hybrid composite based on a bilinear cohesive zone model (BCZM). The effects of embedded SMA fiber number and fiber ratio were respectively discussed. © 2013 Elsevier Ltd.


Liu G.,National University of Singapore | Chen H.,Marine Design and Research Institute of China | Liu D.,Harbin Engineering University | Khoo B.C.,National University of Singapore
Bulletin of the Seismological Society of America | Year: 2010

Wave propagation in a half-space with complex surface configuration is often encountered in fields like seismology and ocean engineering. This article presents a theoretical study of multiple scattering of SH waves by two hills of different geometries (a triangle and a semicircle) on a solid half-space. The standing waves in the triangular and semicircular hills are constructed by the fractional-order Bessel function method and Fourier integral transform method, respectively. The unknown coefficients of the standing waves are determined via the region-matching method. It is shown that the apexes of the hills are very sensitive to the external dynamic load because of multiple incidences; in particular, the apex of the triangular hill exhibiting maximum amplitude is most susceptible to the external load. Furthermore, the effect of the interaction between the triangular and semicircular hills is evaluated. It is found that the amplitudes on the showdown zone that connects the two hills have been largely amplified due to the interaction between the two hills. The mutual interaction between the hills should not be neglected if the distance between them is less than O(100) times the typical dimension of the hill.


Chang J.-C.,National Taipei University of Technology | Hung T.-C.,National Taipei University of Technology | He Y.-L.,Xi'an Jiaotong University | Zhang W.,Harbin Engineering University
Applied Energy | Year: 2015

This paper focuses on experimental performance of an open-drive scroll type expander in an organic Rankine cycle (ORC) system. The expander was an originally oil-free scroll type air compressor with a built-in volume ratio of 4.05. The cycle used HFC-245fa as working fluid, and the loop has been mixed with a moderate concentration of refrigerant oil that circulated in the cycle. The experimental results of this study are divided into two main parts: first part focuses the experimental performance on the fixed superheating at the expander inlet with respect to various pressure differences of the system and rotational speeds of the expander. Second part involves various superheating at the expander inlet which was operated at fixed rotational speed and operating pressure difference of 5. bars and 6. bars. When the cycle was operated under fixed superheating conditions, the maximum cycle efficiency, expander efficiency and power output of the expander are 9.44%, 73.1% and 2.3. kW respectively. On the other hand, when the expander is operated in various superheating conditions, the expander and cycle efficiency simultaneously increase with the increasing of superheating. In addition, this paper not only focuses on the experimental results using the current expander, but also integrates the previous experimental data with present study to identify an appropriate scroll type expander with respect to various operating pressure differences for the heat source below 100. °C. © 2015 Elsevier Ltd.


Yang X.,Harbin Engineering University | Yang X.,National University of Singapore | Low J.M.W.,National University of Singapore | Tang L.C.,National University of Singapore
Journal of Transport Geography | Year: 2011

This paper presents an intermodal network optimization model to examine the competitiveness of 36 alternative routings for freight moving from China to and beyond Indian Ocean. The proposed model, which is built upon the principles of goal programming, is able to handle multiple and conflicting objective functions such as minimizing transportation cost, transit time and transit time variability while ensuring flow continuity and transit nodes compatibility among the rail, road, ocean vessel, airplane and inland waterway transports. Transportation time and cost obtained from comprehensive industry sources are then fed into the intermodal transport network connecting two important Chinese origins and four Indian destinations, from which the most attractive routes are identified. In addition, the paper investigates several non-dominated transportation cases through sensitivity analysis tests, and analyzes the potential competitiveness and possible influences of future route developments to current transportation patterns in Asia. © 2010 Elsevier Ltd.


Su X.,Key Laboratory of Dependable Service Computing | Su X.,Chongqing University | Wu L.,Harbin Institute of Technology | Shi P.,Harbin Engineering University | And 3 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2015

In this paper, the model approximation problem is investigated for a Takagi-Sugeno fuzzy switched system with stochastic disturbance. For a high-order considered system, our attention is focused on the construction of a reduced-order model, which not only approximates the original system well with a Hankel-norm performance but translates it into a lower dimensional fuzzy switched system as well. By using the average dwell time approach and the piecewise Lyapunov function technique, a sufficient condition is first proposed to guarantee the mean-square exponential stability with a Hankel-norm error performance for the error system. The model approximation is then converted into a convex optimization problem by using a linearization procedure. Finally, simulations are provided to illustrate the effectiveness of the proposed theory. © 2014 IEEE.


Li H.,Bohai University | Sun X.,Bohai University | Shi P.,Harbin Engineering University | Shi P.,University of Adelaide | And 2 more authors.
Information Sciences | Year: 2015

This paper focuses on designing sampled-data controller for interval type-2 (IT2) fuzzy systems with actuator fault. The IT2 fuzzy system and the IT2 state-feedback controller share different membership functions. Firstly, considering the mismatched membership functions, the IT2 fuzzy model and the IT2 state-feedback sampled-data controller are constructed. Secondly, based on Lyapunov stability theory, an IT2 state-feedback sampled-data controller is designed such that the closed-loop system is asymptotically stable. The actuator failure is considered in the control systems. The resulting closed-loop system is reliable since the designed controller can guarantee the asymptotic stability and H∞ performance when the actuator experiences failure. The existence condition of the IT2 fuzzy H∞ sampled-data controller can be expressed by solving a convex optimization problem. An inverted pendulum model is utilized to demonstrate the effectiveness of the proposed new design techniques. © 2015 Published by Elsevier Inc.


Song Z.,Kagawa University | Guo S.,Kagawa University | Guo S.,Harbin Engineering University
Journal of Medical and Biological Engineering | Year: 2012

With the development of neurorehabilitation, physical rehabilitation strategies for the upper limbs have become gradually accepted by therapists and researchers. These strategies include intensive intervention, task-oriented training, and bilateral training. Most upper limb rehabilitation systems have been developed for unilateral training. This paper develops an upper limb exoskeleton rehabilitation device (ULERD) that can be used for bilateral training. The device has three active degrees of freedom (DoFs) in the elbow and wrist joints, and an additional four passive DoFs at these joints to correct any misalignment between the human and device joints. A bilateral training strategy is implemented with the developed ULERD and a haptic device according to neurorehabilitation theory. In a preliminary study, a healthy user was able to manipulate the haptic device with one hand (intact hand for hemiplegic patients) when the upper arm was fixed, and the ULERD assisted in moving the other hand (impaired upper limb for hemiplegic patients). To implement bilateral training, the kinematics of one upper limb (intact limb) and the haptic device is analyzed, respectively. The angles of the three active DoFs are determined via integration. An inertia sensor is used to evaluate the kinematics resolution. The ULERD was evaluated by experienced therapists during the design process to determine its potential for clinic application. Experimental results indicate that the kinematics resolution is effective and that this type of bilateral movement can be implemented using the ULERD and the haptic device.


Ren B.,Key Laboratory of Superlight Materials and Surface Technology | Fan M.,Key Laboratory of Superlight Materials and Surface Technology | Liu Q.,Key Laboratory of Superlight Materials and Surface Technology | Wang J.,Key Laboratory of Superlight Materials and Surface Technology | And 3 more authors.
Electrochimica Acta | Year: 2013

NiO nanofibers modified by citric acid (NiO/CA) for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers are investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. Results show that the NiO/CA nanofibers are hollow tube and comprised of many NiO sheets. Furthermore, the NiO/CA nanofibers have good electrochemical reversibility and display superior capacitive performance with large capacitance (336 F g-1), which is 2.5 times of NiO electrodes. Moreover, the NiO/CA nanofibers show excellent cyclic performance after 1000 cycles. © 2013 Elsevier Ltd.


Liang H.,University Of Science And Technology Liaoning | Li X.,Harbin Engineering University
International Journal of Advanced Manufacturing Technology | Year: 2013

Five-axis machining is more widely used in manufacturing of freeform surfaces. However, in five-axis machining of freeform surfaces, incomplete information exchange between computer numerical control (CNC) and computer-aided design/computer-aided manufacturing (CAM) results in many limitations need to be rectified. In the paper, a new structure of CNC based on STEP-NC standard is proposed, where tool path planning, tool offset, and inverse kinematics are transferred from CAM to CNC. In order to guarantee good openness, open platform and standard interface are applied in the development. Technology of module collaboration and design of data flow are studied. A five-axis real-time interpolator for non-uniform rational B-spline surfaces machining is realized. Based on these technologies, a five-axis CNC is developed in the manner of software realization, which consists of interpreter, task coordinator, axis group, softPLC, etc. The software CNC system has been applied on a tilt-rotary type five-axis machine tool, where the milling experiment has been performed successfully. © 2013 Springer-Verlag London.


Kang Z.,Harbin Engineering University | Jia L.-S.,China National Offshore Oil Corporation
Acta Mechanica Sinica/Lixue Xuebao | Year: 2013

In the paper, an experiment investigation was conducted for one- and two-degree of freedom vortex-induced vibration (VIV) of a horizontally-oriented cylinder with diameter of 11 cm and length of 120 cm. In the experiment, the spring constants in the cross-flow and in-line flow directions were regulated to change the natural vibration frequency of the model system. It was found that, in the one-degree of freedom VIV experiment, a "double peak" phenomenon was observed in its amplitude within the range of the reduced velocities tested, moreover, a "2T" wake appeared in the vicinity of the second peak. In the two-degree of freedom VIV experiment, the trajectory of cylinder exhibited a reverse "C" shape, i.e., a "new moon" shape. Through analysis of these data, it appears that, besides the non-dimensional in-line and cross-flow natural vibration frequency ratios, the absolute value of the natural vibration frequency of cylinder is also one of the important parameters affecting its VIV behavior. © 2013 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.


Jia H.-M.,Harbin Engineering University
Proceedings - 2013 International Conference on Communication Systems and Network Technologies, CSNT 2013 | Year: 2013

Appropriate response of immune system to variety antigen is the key organisms to maintain a stable internal environment. It mainly depends on the regulation of T cell. The function of T cells is both active and inhibitive, which provides immune system with fast response and adequate stabilization. Based on the immune system regulating law and comparison the control system and the immune system, an immune PID controller is proposed in this paper. The effects of parameters of immune PID controller are described. Simulation results obtained for wood drying control system with parameters changing and perturbations demonstrate the effectiveness of the immune PID control system. © 2013 IEEE.


Li H.,Bohai University | Gao Y.,Harbin Institute of Technology | Shi P.,Harbin Engineering University | Shi P.,Victoria University of Melbourne | And 2 more authors.
IEEE Transactions on Automatic Control | Year: 2016

In this technical note, a new fault detection design scheme is proposed for interval type-2 (IT2) Takagi-Sugeno (T-S) fuzzy systems with sensor fault based on a novel fuzzy observer. The parameter uncertainties can be captured by the membership functions of the IT2 fuzzy model. The premise variables of the plant are perfectly shared by the fuzzy observer. A stochastic process between the plant and the observer is considered in the system. A fault sensitive performance is established, and then sufficient conditions are obtained for determining the fuzzy observer gains. Finally, simulation results are provided to verify the effectiveness of the presented scheme. © 1963-2012 IEEE.


Gao P.,Harbin Engineering University
ACS Applied Materials and Interfaces | Year: 2013

In the paper, we developed an in situ diffusion growth method to fabricate porous Fe2(MoO4)3 nanorods. The average diameter and the length of the porous nanorods were 200 nm and 1.2-4 μm, respectively. Moreover, many micropores existed along axial direction of the Fe2(MoO4)3 nanorods. In terms of nitrogen adsorption-desorption isotherms, calculated pore size was in the range of 4-115 nm, agreeing well with the transmission electron microscope observations. Because of the uniquely porous characteristics and catalytic ability at low temperatures, the porous Fe2(MoO4)3 nanorods exhibited very good H2S sensing properties, including high sensitivity at a low working temperature (80 C), relatively fast response and recovery times, good selectivity, and long-term stability. Thus, the porous Fe2(MoO4)3 nanorods are very promising for the fabrication of high-performance H2S gas sensors. Furthermore, the strategy presented here could be expended as a general method to synthesize other hollow/porous-type transition metal molybdate nanostructures by rational designation in nanoscale. © 2013 American Chemical Society.


Wen Q.,Harbin Engineering University | Wang S.,Harbin Engineering University | Chen Y.,Harbin Engineering University | Cong L.,Harbin Engineering University | Qu Y.,Harbin Engineering University
Journal of Hazardous Materials | Year: 2013

Bioelectrochemical systems (BESs), such as microbial fuel cells (MFCs) and microbial electrolysis cells (MECs), are generally regarded as a promising key technology to effectively treat wastewater and better exploit the renewable resource. This study explored the use of a BES to abiotically cathodic dechlorination of aromatic chlorides such as 4-chlorophenol, where the process was driven by microbial oxidation of glucose at the anode. It was confirmed that the 4-CP reduction process was feasible in BES and the dechlorination efficiency of 4-CP could achieve 50.3% at the cathode with energy generation. The 4-CP dechlorination efficiency was significantly enhanced when the BES was supplied with voltages, reaching up to 92.5% at an energy consumption of 0.549kWhmol-1 4-CP (at applied voltage of 0.7V). Besides, phenol was identified as the major product of 4-CP dechlorination at the cathode of BES in this study, which was the same as electrochemical reduction. © 2012 Elsevier B.V.


Meng Z.X.,Harbin Engineering University | Zheng W.,Harbin Engineering University | Li L.,Harbin Engineering University | Zheng Y.F.,Harbin Engineering University | Zheng Y.F.,Peking University
Materials Chemistry and Physics | Year: 2011

In this study both aligned and randomly oriented poly(d,l-lactide-co- glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which would be beneficial for drug release. © 2010 Elsevier B.V. All rights reserved.


Wu L.,Harbin Engineering University | Su X.,Harbin Institute of Technology | Shi P.,University of Adelaide | Shi P.,Victoria University of Melbourne
IEEE Transactions on Automatic Control | Year: 2014

This paper is concerned with the induced ℓ2 dynamic output feedback controller (DOFC) design problem for discrete-time Markovian jump repeated scalar nonlinear systems. By employing both the switching-sequence dependent Lyapunov function approach and the positive definite diagonally dominant Lyapunov function technique, a sufficient condition is first established, which guarantees the underlying system to be stochastically stable with an induced ℓ2 disturbance attenuation performance. Then the desired full- or reduced-order DOFCs are designed by using projection approach. Cone complementarity linearization procedure is employed to cast the nonconvex feasibility problem into a sequential minimization problem. Finally, a numerical example is presented to show the effectiveness of the proposed methods. © 2013 IEEE.


Sun Y.,Harbin Normal University | Sun Y.,Peking University | Ma L.,Harbin Normal University | Zhou B.,Harbin Normal University | Gao P.,Harbin Engineering University
International Journal of Hydrogen Energy | Year: 2012

Our recent progress shows that Cu(OH)2 and CuO nanoribbon arrays exhibit notable electrochemical hydrogen storage capacities of 180 and 160 mAh/g, respectively, which also suggests that porous or tubular nanostructures can have a higher ability of hydrogen uptake. Two dimensional (2D) networks consisting of crossed Cu(OH)2 nanotubes were prepared by a simple topotactic transformation process, including the fabrication of hexaoxacyclooctadecane-like intermediate posnjakite microplates and their subsequent chemical transformation into Cu(OH)2 nanotube networks, which further dehydrated to produce CuO nanotube networks with partial morphological preservation. The formation of half-tube and half-ribbon structures, nanoribbons, and nanotubes during the transformation processes revealed that the deformations of corrugated posnjakite sheets to give lamellar Cu(OH)2 with rolling into tubular structures could be responsible for the growth of Cu(OH)2 nanotube networks from posnjakite microplates. The Cu(OH)2 and CuO nanotube networks could electrochemically charge and discharge with higher hydrogen storage capacities of 220 and 188 mAh/g than the Cu(OH)2 and CuO nanoribbon arrays at room temperature, respectively, which made them promising candidates for hydrogen storage, high-energy batteries and catalytic fields. Based on the rolling mechanism of layered structural materials, this simple topotactic transformation route might be extendable to the preparation of novel nanotube networks with higher capacities of hydrogen storage if appropriate precursors of numerous materials with layered structures were treated in solution. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Li H.,Bohai University | Wang J.,Bohai University | Shi P.,Harbin Engineering University | Shi P.,Victoria University of Melbourne | Shi P.,University of Adelaide
IEEE Transactions on Fuzzy Systems | Year: 2015

In this paper, a novel adaptive sliding mode controller is designed for Takagi-Sugeno (T-S) fuzzy systems with actuator saturation and system uncertainty. By delta operator approach, the discrete-time nonlinear system is described by a T-S fuzzy model with unmeasurable state. By singular value decomposition (SVD) of system input matrix, a reduced-order system is obtained for the design of sliding mode surface. A new adaptive sliding mode controller based on system output is presented to guarantee that the closed-loop system is uniformly ultimately bounded (UUB). Four examples are provided to illustrate the effectiveness and applicability of the proposed control scheme. © 2015 IEEE.


Kang Z.,Harbin Engineering University | Jia L.,China National Offshore Oil Corporation
Ocean Engineering | Year: 2013

The paper reports the results of experiments on the vortex-induced vibration of a horizontal cylinder with two degrees of freedom and with the diameter of 5 cm, and length of 120 cm. It has been found that the vibration of the cylinder in in-line direction appeared to be "multi-frequency". That is, under certain combinations of natural vibration frequency and reduced velocity, the in-line vibration frequency contained both the cross-flow vibration frequency and two times the cross-flow vibration frequency. Consequently, the trajectories of the cylinder were "egg" and "raindrop" shapes, which were significantly different from the traditional figure "8" and "new moon" shapes. In addition, the study found that the vibration trajectory in other forms moves towards a figure "8" shape as xxx increases. Also, it was found that the various forms of cylinder vortex vibration trajectories depended primarily on the combination of natural vibration frequency and reduced velocity. © 2013 Published by Elsevier Ltd. All rights reserved.


Jia X.,Beijing Normal University | Jia X.,University of New South Wales | Wang L.,Harbin Engineering University
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014

While a single spectrum is often used to present a pure class, it is more realistic to consider intra-class spectral variation and model a pure class using a group of its representative spectra. In line with this consideration, crisp unmixing accuracy assessment, where unmixing performance is assessed using a mean squared error of the estimated endmember fractions, can be misleading. In this paper, alterative spectral unmixing assessment methods are introduced to account for the uncertainty contained in the spectral measurements and during the ground truth data collection. Two fuzzy measures are developed to assess unmixing performance. One is fuzzy unmixing fraction error for a realistic assessment and the other is pixel level unmixing accuracy to provide a good quantitative understanding of the unmixing success rates spatially. To demonstrate and illustrate how they work, the two fuzzy measures are applied to evaluate the performance of several spectral unmixing methods including both single spectrum based and multiple spectra based algorithms. Crisp assessments and fuzzy results at various tolerance levels are presented and compared. Based on the realistic measures proposed, it is found the recent developed unmixing method with extended Support Vector Machines outperforms other algorithms tested. © 2013 IEEE.


News Article | October 23, 2015
Site: news.mit.edu

Mujid S. Kazimi, the TEPCO Professor of Nuclear Engineering and one of the world’s foremost educators and researchers in nuclear technology, died suddenly on Wednesday in China. Kazimi, who was 67, suffered a heart attack while visiting Harbin Engineering University to participate in an international advisory committee. He held faculty appointments in MIT’s Departments of Nuclear Science and Engineering (NSE) and Department of Mechanical Engineering, and was director of both MIT’s Center for Advanced Nuclear Energy Systems and the Kuwait-MIT Center for Natural Resources and the Environment. He served as NSE’s department head from 1989 to 1997. Current NSE department head Richard Lester shared the news of Kazimi’s death in an email to the department’s faculty on Wednesday, describing it as “a devastating blow.” “The international community knew Mujid as one of the world’s great nuclear engineers,” Lester told MIT News. “In NSE, we also knew him as a wonderful human being. Wise, kind, tough when he needed to be, but always gracious and respectful toward his students and his colleagues — he was a true gentleman, and he was a good man. His dedication and loyalty to his students, and to the department, were inspirational. It is a huge loss for our department, and for our field. But his colleagues in NSE are grateful for the privilege of knowing and serving with him.” Kazimi was born in Jerusalem in 1947, and later moved with his family to Amman, Jordan. He earned his bachelor’s degree in nuclear engineering from Alexandria University in Egypt in 1969, then came to MIT, where he earned an SM in 1971 and a PhD in 1973. Before joining the MIT faculty in 1976, Kazimi worked briefly at Westinghouse Electric Corp. and Brookhaven National Laboratory. Kazimi was an expert in the design and analysis of nuclear power plants and the nuclear fuel cycle. He supervised 45 PhD theses and 80 master’s theses at MIT; Lester notes that many of his students have gone on to faculty positions at universities worldwide, or to leadership positions in the nuclear energy field. Kazimi was dedicated to the advancement of the profession, and advised governments, universities, and research institutions on the development of nuclear energy. He authored over 200 scientific papers, and co-authored, with Neil Todreas, a two-volume textbook, “Nuclear Systems.” Lester says that Kazimi’s contributions to the field included “numerous technological advances that promise to enhance the safety and economics of nuclear power plants.” Among his most important contributions are the development of annular fuel with internal and external cooling, offering the potential for dramatic reductions in the fuel operating temperature, thereby reducing the thermal energy stored in the fuel. Kazimi also led efforts to develop a ceramic fuel cladding made of silicon carbide to replace the zirconium alloy cladding that is currently used in most reactor fuel. This new cladding, Lester says, “has the potential to reduce significantly the consequences of loss-of-coolant accidents in light water reactors,” because it greatly reduces the generation of potentially explosive hydrogen in such accidents. Kazimi also made “a number of influential contributions to the development of technological strategies for the nuclear fuel cycle,” Lester says. “His research generated fundamental insights into the range of options for fuel-recycling technologies, enabling the sustainable development of nuclear energy along economically competitive paths that will take advantage of the abundance of natural uranium.” Kazimi co-chaired, with Ernest Moniz — the former MIT physicist who is now the U.S. Secretary of Energy — an influential, and widely read, interdisciplinary study on the future of the nuclear fuel cycle. Kazimi received many honors for his work. He was a member of the National Academy of Engineering, a fellow of the American Nuclear Society and the International Nuclear Energy Academy, and recipient of the Kuwait Prize in Applied Sciences in 2011. Kazimi served on many boards, including the board of trustees of Al-Quds University in Jerusalem, a committee on the rejuvenation of scientific research in Kuwait, and the international advisory board on nuclear energy for the United Arab Emirates. He was a member of the Nuclear Energy Advisory Committee of the U.S. Department of Energy, and at the time of his death was chairing its subcommittee on nuclear reactor technology. Lester described Kazimi as “one of the world’s most distinguished educators and researchers in the field of nuclear technology. His outstanding scientific and engineering achievements are recognized around the world.” Kazimi is survived by his wife of 41 years, Nazik Denny, by three children — daughter Yasmeen and sons Marwan (a 1996 MIT alumnus) and Omar — and by three grandchildren. A memorial service for Kazimi will be held Oct. 1 in MIT's Bartos Theater, E15-070, beginning at 4:00 p.m. A reception will follow. Donations in his memory can be made to The Mujid S. Kazimi Memorial Fund to support future NSE graduate students. For any questions about the memorial service, contact Carolyn Carrington at carrin@mit.edu or 617-253-7407.


Xie X.,Shanghai JiaoTong University | Zheng H.,Shanghai JiaoTong University | Jin G.,Harbin Engineering University
Composites Part B: Engineering | Year: 2015

Abstract The objective of this work is to present a Haar Wavelet Discretization (HWD) method-based solution approach for the free vibration analysis of functionally graded (FG) spherical and parabolic shells of revolution with arbitrary boundary conditions. The first-order shear deformation theory is adopted to account for the transverse shear effect and rotary inertia of the shell structures. Haar wavelet and their integral and Fourier series are selected as the basis functions for the variables and their derivatives in the meridional and circumferential directions, respectively. The constants appearing in the integrating process are determined by boundary conditions, and thus the equations of motion as well as the boundary condition equations are transformed into a set of algebraic equations. The proposed approach directly deals with nodal values and does not require special formula for evaluating system matrices. Also, the convenience of the approach is shown in handling general boundary conditions. Numerical examples are given for the free vibrations of FG shells with different combinations of classical and elastic boundary conditions. Effects of spring stiffness values and the material power-law distributions on the natural frequencies of shells are also discussed. Some new results for the considered shell structures are presented, which may serve as benchmark solutions. © 2015 Elsevier Ltd. All rights reserved.


Zheng L.,Harbin Engineering University | Zheng L.,Hejiang Institute of Agriculture Science | Shi D.,Kyungpook National University | Zhang J.,Hejiang Institute of Agriculture Science
Pattern Recognition Letters | Year: 2010

In this paper, a hybrid method of combining the mean shift (MS) with the Fisher linear discriminant (FLD) is implemented to improve the performance of crop image segmentation. The highlight is the adoption of a point-line-distance-based strategy for weighting training data at the stage of the FLD. A wide set of images was employed to test the proposed method, and the results demonstrate its high quality and stable performance. In addition, the simulation results show that the point-line-distance-based strategy takes affect via enlarging the distance of class means, increasing the between-class scatter while decreasing the within-class scatter. © 2010 Elsevier B.V. All rights reserved.


Zhang J.,Harbin Engineering University | Qiao G.,Harbin Engineering University | Wang C.,Shanghai Marine Equipment Research Institute
Proceedings - 2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012 | Year: 2012

Acoustic modem is one of the key components of underwater acoustic communication, in order to adapt to the complex and changeable acoustic environment and complete the underwater sensor network, an intelligent modem management platform is needed to achieve the parameter adjustment and the network protocol operation, while the commercial underwater acoustic modems which are already in use are hard to meet this requirement. In this paper, we designed and implemented an intelligent underwater acoustic modem management platform, based on the chip ARM6410. The platform supports the executable program written by users, and can complete the functions of modem state control, data storage and forwarding, and network protocol implementation. Experiments on testing capability of the platform were conducted in the yellow sea, results show that the management platform performs well. © 2012 IEEE.


Yu H.,Harbin Engineering University | Wang T.,Harbin Engineering University | Wen B.,Beijing Institute of Technology | Lu M.,Beijing Institute of Technology | And 6 more authors.
Journal of Materials Chemistry | Year: 2012

In the paper, we find that graphene has a strong dielectric loss, but exhibits very weak attenuation properties to electromagnetic waves due to its high conductivity. As polyaniline nanorods are perpendicularly grown on the surface of graphene by an in situ polymerization process, the electromagnetic absorption properties of the nanocomposite are significantly enhanced. The maximum reflection loss reaches -45.1 dB with a thickness of the absorber of only 2.5 mm. Theoretical simulation in terms of the Cole-Cole dispersion law shows that the Debye relaxation processes in graphene/polyaniline nanorod arrays are improved compared to polyaniline nanorods. The enhanced electromagnetic absorption properties are attributed to the unique structural characteristics and the charge transfer between graphene and polyaniline nanorods. Our results demonstrate that the deposition of other dielectric nanostructures on the surface of graphene sheets is an efficient way to fabricate lightweight materials for strong electromagnetic wave absorbents. © 2012 The Royal Society of Chemistry.


Chen Y.,Harbin Engineering University | Wang Q.,Harbin Engineering University | Zhu C.,Harbin Engineering University | Gao P.,Harbin Engineering University | And 4 more authors.
Journal of Materials Chemistry | Year: 2012

Graphene/porous cobalt nanocomposite was successfully prepared through a facile method, whose hydrogen storage capacity was up to 241.9 mA h g -1 at room temperature, higher than those of graphene and commercial cobalt. This journal is © The Royal Society of Chemistry 2012.


Ye X.,Harbin Engineering University | Liu S.,Harbin Engineering University | Liu P.X.,Carleton University
IET Control Theory and Applications | Year: 2010

The modelling and stabilising control of networked control systems (NCSs) with stochastic packet loss and time-varying delays are addressed. In specific, a novel Markovian jump linear system with time-varying delays is used to model the NCS. Without using the augmented state method, sufficient conditions for the stochastic stabilisation of the NCS with packet loss and time-varying delays are obtained via the mode-dependent Lyapunov function method. The mode-dependent controller for the closed-loop NCS is presented in the linear matrix inequalities formulation via the Shur complement theory. A numerical example is given to illustrate the effectiveness of the proposed method. © 2010 The Institution of Engineering and Technology.


Cao J.,Beijing University of Posts and Telecommunications | Gao H.,Harbin Engineering University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In order to solve discrete optimization problem, this paper proposes a quantum-inspired bacterial swarming optimization (QBSO) algorithm based on bacterial foraging optimization (BFO). The proposed QBSO algorithm applies the quantum computing theory to bacterial foraging optimization, and thus has the advantages of both quantum computing theory and bacterial foraging optimization. Also, we use the swarming pattern of birds in block introduced in particle swarm optimization (PSO). Then we evaluate the efficiency of the proposed QBSO algorithm through four classical benchmark functions. Simulation results show that the designed algorithm is superior to some previous intelligence algorithms in both convergence rate and convergence accuracy. © 2012 Springer-Verlag.


Sun X.,Harbin Engineering University | He J.,Harbin Engineering University | Li X.,Design Institute Ltd Company of CSCEC. | Lv J.,Harbin Engineering University
Ceramics International | Year: 2014

BiPO4:xEu3+ powders were synthesized by a solid state reaction method. The BiPO4:xEu3+ samples were characterized by X-ray powder diffraction (XRD), infrared spectra (IR), scanning electron microscopy (SEM), and luminescence spectroscopy. The XRD and IR results reveal that the BiPO4:xEu3+ samples present monoclinic phases. The SEM observations demonstrate that the BiPO 4:xEu3+ powders are regular polyhedrons with particle sizes in the range of 50-300 nm. The excitation spectra of BiPO 4:xEu3+ samples show that there exist the broad band at 288 nm and many sharp peaks in the wavelength range of 310-550 nm. The emission spectra of BiPO4:xEu3+ samples display the bands associated to the 5D0→7FJ electronic transitions characteristics of the Eu3+ ions at different positions. The concentration quenching will occur when the dosage concentration reached a value of 5 mol%. © 2013 Elsevier Ltd and Techna Group S.r.l.All rights reserved.


Wang X.,KTH Royal Institute of Technology | Wang X.,Harbin Engineering University | Ma Y.,KTH Royal Institute of Technology | Ma Y.,Harbin Engineering University | Zhu B.,KTH Royal Institute of Technology
International Journal of Hydrogen Energy | Year: 2012

Solid oxide fuel cells (SOFCs) are considered as one of the most promising power-generation technologies. However, the current high operation temperature (800-1000 °C) of SOFCs impedes their commercialization significantly. A key requirement for reducing the operation temperature of SOFCs is to improve the performance of the electrolyte at such low temperature. Recently, ceria-based composite materials, especially ceria-carbonate composites (3C), have been developed as competitive electrolyte candidates for SOFCs operated below 600 °C, which resulted in an emerging R & D upsurge followed up by worldwide activities. This report gives a short review on current worldwide activities on 3C for advanced low temperature ceramic fuel cells (LTCFCs), which mainly based on recent more than 70 publications since 2010. It gives an overview of materials composition and microstructure, multi-ion conduction effects, durability of the 3C materials in the areas of LTCFC or joint SOFC/MCFC filed, as well as some other novel applications of the 3C materials. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Sun X.,Harbin Engineering University | Li X.,Design Institute Ltd Company of CSCEC | He J.,Harbin Engineering University | Wang B.,Harbin Engineering University
Journal of Materials Science: Materials in Electronics | Year: 2014

Barium tungstate (BaWO4) nanorods were synthesized by a hydrothermal process with the assistant of cetyltrimethyl ammonium bromide (CTAB). The samples were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and photoluminescence measurements. The XRD and FT-IR results show that BaWO 4 samples can be indexed as a pure tetragonal scheelite structure. The SEM results show that the morphologies are nanorods with a diameter about 45 nm and a length exceeding 1 μm. The CTAB and "oriented attachment" play key roles in the growth of BaWO4 nanorods in the hydrothermal process. When excited at 265 nm, BaWO4 nanorods show the intrinsic emission band centered at 467 nm. The calculated luminescence lifetime of WO4 2- in BaWO4 is 8.9 μs. © 2014 Springer Science+Business Media New York.


Zheng L.,Harbin Engineering University | Shi D.,Kyungpook National University
IEEE Signal Processing Letters | Year: 2010

A maximum-amplitude-based coarse-to-fine algorithm is proposed with two novel ideas highlighted: adopting the maximum value of the fractional Fourier amplitude spectrum to measure the compactness of a signal, and using a coarse-to-fine strategy to speed up the searching process. The simulation results on synthetic and real signals show the validity of the proposed method. © 2010 IEEE.


Sun C.,University of Texas at Austin | Sun C.,CAS Institute of Physics | Rajasekhara S.,University of Texas at Austin | Chen Y.,Harbin Engineering University | Goodenough J.B.,University of Texas at Austin
Chemical Communications | Year: 2011

A solvothermal method was developed to prepare on a large scale monodisperse porous β-Co(OH)2 microspheres consisting of nanoplatelets. Co3O4 microspheres with porous platelets were obtained via subsequent thermal decomposition. These Co3O 4 microspheres show much higher ethanol sensitivity and selectivity at a relatively low temperature (135 °C) compared with those of commercial Co3O4 nanoparticles. © 2011 The Royal Society of Chemistry.


Dai Y.,CAS Changchun Institute of Applied Chemistry | Dai Y.,University of Chinese Academy of Sciences | Xiao H.,University of Notre Dame | Liu J.,Jilin University | And 8 more authors.
Journal of the American Chemical Society | Year: 2013

Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core-shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-[Pt(N3) 2(NH3)(py)(O2CCH2CH 2COOH)2]. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy. © 2013 American Chemical Society.


Xu F.,Shanghai JiaoTong University | Zou Z.-J.,Shanghai JiaoTong University | Yin J.-C.,Shanghai JiaoTong University | Cao J.,Harbin Engineering University
Ocean Engineering | Year: 2013

An identification method based on support vector machines (SVM) is proposed for modeling nonlinear dynamics of underwater vehicles (UVs), and a typical torpedo-shaped autonomous underwater vehicle (AUV) is employed for the purpose of validation. To obtain the hydrodynamic derivatives of the vehicle and the dynamical models of the thruster and fins, a series of hydrodynamic experiments are conducted by using vertical planar motion mechanism (PMM) and circulating water channel (CWC). Maneuvering simulation is carried out by using the hydrodynamic model obtained from experiments, and SVM is applied to identify the damping terms together with Coriolis and centripetal terms by analyzing the simulation data. By using the identified nonlinear model and experiment-based hydrodynamic model respectively, maneuvering simulations and control applications are implemented. The results are compared to verify the proposed method, and the effectiveness and good generalization performance of SVM in modeling the nonlinear dynamics of UVs are demonstrated. © 2013 Elsevier Ltd. All rights reserved.


Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University | Gao H.,Harbin Engineering University | Meng F.L.,Harbin Engineering University | Zhang M.,Harbin Engineering University
Electrochimica Acta | Year: 2013

Li2+xMn1-xPxSi1-xO4 are prepared by a sol-gel method and characterized as novel cathode materials for lithium ion batteries. Single-phase Li2+xMn1-xPxSi 1-xO4 can be obtained when x is equal to 0, 0.05 and 0.1 and the calcination temperature is 700 °C. Calcining at 900 °C is of no avail to prepare single-phase Li2+xMn1-xP xSi1-xO4. Incontrast to Li 2MnSiO4 and Li2.1 Mn0.9 P 0.1 Si0.9 O4,Li2.05 Mn 0.95P0.05 Si0.95 O4 has nearly the same structure at both calcination temperatures. The Li2.05Mn 0.95P0.05Si0.95O4/C sample calcined at 700 °C has the best electrochemical performance among the three single-phase samples, which is in accordance with the fact that it has the lowest charge transfer resistance. Smaller particle size and larger specific surface area are obtained at higher x value, and all the Li2+xMn 1-xPxSi1-xO4/C (x = 0,0.05 and 0.1) samples have a core-shell structure. The calcination temperature of 700 ° C is the best between 600 and 800 °C in consideration of both phase purity and crystallinity, resulting in the highest discharge capacity of Li2.05 Mn0.95P0.05Si0.95 O4. © 2013 Elsevier Ltd. All rights reserved.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University | Wu Y.,Harbin Normal University
Nanoscale | Year: 2015

Both high safety and low cost give aqueous rechargeable sodium-ion batteries (ARSB) the opportunity for application in stationary energy storage, but the low operating potential of the existing cathode materials limits its energy density. Here, we introduce a hydrothermal-assisted strategy to prepare the Na7V4(P2O7)4(PO4)/C nanorod and employ it as a novel high-property cathode material for ARSB. The hierarchical structure is formed by direct in situ carbonization of the surfactants (CTAB and oxalic acid) along with the crystallization of Na7V4(P2O7)4(PO4). The prepared Na7V4(P2O7)4(PO4) with a well-defined 1D nanostructure and uniform particle size is wrapped with a thin carbon layer. For the first time, its sodium intercalation chemistry in an aqueous electrolyte was investigated. Based on the reversible phase transformation and high sodium diffusion coefficient, it is demonstrated to be reliable in an aqueous electrolyte with the rapid ion transport capability. A pair of redox plateaus is observed in the charge and discharge curves at 0.961 and 0.944 V (vs. SCE) respectively with the capacity of 51.2 mA h g-1 at 80 mA g-1. Favored by the open ion channel and 1D morphology, the composite exhibits superior high rate capability and 72% of the capacity remains at 1000 mA g-1. The results not only demonstrate a high-property cathode material for ARSB, but also are helpful for design and synthesis of mixed-polyanion electrode materials with tailored architecture. This journal is © The Royal Society of Chemistry.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University
ACS Applied Materials and Interfaces | Year: 2014

Tailoring materials into nanostructure offers unprecedented opportunities in the utilization of their functional properties. High-purity Na 7V4(P2O7)4(PO 4) with 1D nanostructure is prepared as a cathode material for rechargeable Na-ion batteries. An efficient synthetic approach is developed by carefully controlling the crystal growth in the molten sodium phosphate. Based on the XRD, XPS, TG, and morphological characterization, a molten-salt assisted mechanism for nanoarchitecture formation is revealed. The prepared Na 7V4(P2O7)4(PO 4) nanorod has rectangle sides and preferential [001] growth orientation. GITT evaluation indicates that the sodium de/intercalation of Na7V4(P2O7)4(PO 4) nanorod involves V3+/V4+ redox reaction and Na5V3.5+ 4(P2O7) 4(PO4) as intermediate phase, which results in two pairs of potential plateaus at the equilibrium potentials of 3.8713 V (V 3+/V3.5+) and 3.8879 V (V3.5+/V4+), respectively. The unique nanoarchitecture of the phase-pure Na7V 4(P2O7)4(PO4) facilitates its reversible sodium de/intercalation, which is beneficial to the high-rate capability and the cycling stability. The Na7V4(P 2O7)4(PO4) cathode delivers 80% of the capacity (obtained at C/20) at the 10 C rate and 95% of the initial capacity after 200 cycles. Therefore, it is feasible to design and fabricate an advanced rechargeable sodium-ion battery by employment of 1D nanostructured Na 7V4(P2O7)4(PO 4) as the cathode material. © 2014 American Chemical Society.


Shi J.H.,Nanjing Southeast University | Shi J.H.,Harbin Engineering University | Ma H.F.,Nanjing Southeast University | Guan C.Y.,Harbin Engineering University | And 2 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

A broadband asymmetric transmission of linearly polarized waves with totally suppressed copolarization transmission is experimentally demonstrated in ultrathin 90°-twisted Babinet-inverted metasurfaces constructed by an array of asymmetrically split ring apertures. The only accessible direction-dependent cross-polarization transmission is allowed in this anisotropic chiral metamaterial. Through full-wave simulation and experiment results, the bilayered Babinet-inverted metasurface reveals broadband artificial chirality and asymmetric transmission, with a transmission contrast that is better than 17.7 dB within a 50% relative bandwidth for two opposite directions. In particular, we can modify polarization conversion efficiency and the bandwidth of asymmetric transmission via parametric study. © 2014 American Physical Society.


Lu X.,Harbin Engineering University | Shi J.,Harbin Engineering University | Shi J.,Nanjing Southeast University | Liu R.,Harbin Engineering University | Guan C.,Harbin Engineering University
Optics Express | Year: 2012

We propose, design and experimentally demonstrate highlydispersive electromagnetically induced transparency (EIT) in planar symmetric metamaterials actively switched and controlled by angles of incidence. Full-wave simulation and measurement results show EIT phenomena, trapped-mode excitations and the associated local field enhancement of two symmetric metamaterials consisting of symmetrically split rings (SSR) and a fishscale (FS) metamaterial pattern, respectively, strongly depend on angles of incidence. The FS metamaterial shows much broader spectral splitting than the SSR metamaterial due to the surface current distribution variation. © 2012 Optical Society of America.


Fan Z.-J.,Harbin Engineering University | Yan J.,Harbin Engineering University | Wei T.,Harbin Engineering University | Ning G.-Q.,China University of Petroleum - Beijing | And 5 more authors.
ACS Nano | Year: 2011

We report on the fabrication of 3D carbonaceous material composed of 1D carbon nanofibers (CNF) grown on 2D graphene sheets (GNS) via a CVD approach in a fluidized bed reactor. Nanographene-constructed carbon nanofibers contain many cavities, open tips, and graphene platelets with edges exposed, providing more extra space for Li+ storage. More interestingly, nanochannels consisting of graphene platelets arrange almost perpendicularly to the fiber axis, which is favorable for lithium ion diffusion from different orientations. In addition, 3D interconnected architectures facilitate the collection and transport of electrons during the cycling process. As a result, the CNF/GNS hybrid material shows high reversible capacity (667 mAh/g), high-rate performance, and cycling stability, which is superior to those of pure graphene, natural graphite, and carbon nanotubes. The simple CVD approach offers a new pathway for large-scale production of novel hybrid carbon materials for energy storage. © 2011 American Chemical Society.


Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University | Meng Y.,Harbin Engineering University
Journal of Materials Chemistry A | Year: 2014

Mixed polyanion materials with a 3D framework for battery electrodes have been attracting significant attention recently in view of the requirements to further improve energy storage and power densities. Herein, we present a design of a hierarchical Na7V4(P2O7)4(PO4)/C nanorod-graphene composite as sodium- and lithium-storage cathode materials. The hierarchical structure is composed of a 1D rectangular Na7V4(P2O7)4(PO4)/C nanorod, which is coated by in situ residual carbon and wrapped by a reduced graphene-oxide sheet. The open network of graphene and the surface carbon coating of the Na7V4(P2O7)4(PO4)/C nanorod provide bicontinuous electron and ion pathways, providing a three-dimensional conductive network for efficient electron and ion transfer. The flexible electrode built from the hierarchical composite free of binder or conductive additive exhibits improved electron conductivity and higher sodium/lithium ion migration coefficients than the pristine Na7V4(P2O7)4(PO4)/C nanorod. It approaches the initial reversible electrochemical capacities of 91.4 and 91.8 mA h g-1 with high discharge potentials over 3.8 V (vs. Na/Na+ or Li/Li+) and good cycling properties with capacity retentions of 95% and 83% after 200 cycles at a 1 C rate in sodium and lithium intercalation systems, respectively. Even at 10 C, it still delivers 87.4% (for sodium) and 78.2% (for lithium) of the capacity and high cycling stability. Taking into consideration the compatibilities of both sodium/lithium ions and their superior electrochemical characteristics, the bicontinuous hierarchical composite is considered to be a promising high-rate capability electrode material for advanced energy storage applications. © The Royal Society of Chemistry 2014.


Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University | Fu B.L.,Harbin Engineering University | Yang S.Y.,Harbin Engineering University | Ma L.,Harbin Normal University
Journal of Electroanalytical Chemistry | Year: 2010

Li2Fe0.97Mg0.03SiO4 and Li 2FeSiO4 have been synthesized via a sol-gel method. The effects of Mg doping on the characteristics of Li2FeSiO4 are investigated. Both Li2Fe0.97Mg0.03SiO 4 and Li2FeSiO4 have a monoclinic structure (space group: P21) and their lattice parameters are similar, which indicates that Mg2+ has been doped into the structure of Li 2FeSiO4 without destroying its lattice structure. Mg doping improves the discharge capacity and cycle stability of Li 2FeSiO4. Electrochemical impedance analysis shows that Mg doping decreases charge transfer resistance of Li2FeSiO4, and moreover, Mg doping increases the lithium ion diffusion coefficient of Li2FeSiO4 by one order of magnitude. Compared with Li 2FeSiO4, the higher lithium ion diffusion capability of Li2Fe0.97Mg0.03SiO4 results in its higher reversible capacity, especially at high rates. Furthermore, Mg 2+ is unchangeable during cycling, which stabilizes the crystal structure and results in higher cycle stability of Li2Fe 0.97Mg0.03SiO4.© 2009 Elsevier B.V.


Chen Y.,East China University of Science and Technology | Liu X.,East China University of Science and Technology | Liu X.,University of Pennsylvania | Mao X.,East China University of Science and Technology | And 3 more authors.
Nanoscale | Year: 2014

Ferromagnetic γ-Fe2O3 nanoparticles were successfully loaded into multi-walled carbon nanotubes (MWNTs) as probed by transmission electron microscopy. Upon incorporation of the γ-Fe 2O3-MWNTs into poly(p-phenylenebenzobisoxazole) (PBO), a conjugated polymer with high mechanical strength and outstanding thermal and oxidative stability, microwave absorbing materials were obtained. Attributed to the special structure of the γ-Fe2O3-MWNTs, synergistic effects on dielectric loss and magnetic loss, and a better matched characteristic impedance of the composites were achieved. The optimal minimum reflection loss reached -32.7 dB at 12.09 GHz on a composite containing 12 wt% γ-Fe2O3-MWNTs with a thickness of 2.7 mm, and the corresponding bandwidth below -5 dB was 6.2 GHz. This demonstrated its potential applications as a low-density microwave absorbing material operating under extreme environments. © The Royal Society of Chemistry 2014.


Ren Y.,Harbin Engineering University | Zhu C.,Harbin Engineering University | Qi L.,Harbin Engineering University | Gao H.,Harbin Normal University | Chen Y.,Harbin Engineering University
RSC Advances | Year: 2014

We developed a seed-assisted method to grow ultra-thin γ-Fe 2O3 nanosheets with a paramagnetic behaviour on the surfaces of graphene sheets. Scanning electron microscopy and the transmission electron microscopy measurements showed that the length, height and thickness of the nanosheets were about 140, 120 and 5 nm, respectively. The measured electromagnetic parameters indicated that the three-dimensional (3D) graphene/γ-Fe2O3 nanosheet arrays exhibited a significantly enhanced electromagnetic wave absorption property compared to that of the graphene sheets and some magnetic nanomaterials. The minimal reflection loss was less than -15.2 dB for 3D graphene/γ-Fe2O3 nanosheet arrays with thicknesses of 2 mm, and it was up to -64.1 dB when the thickness was 4.92 mm. Good electromagnetic wave absorption properties of the 3D graphene/γ-Fe2O3 nanosheet arrays indicate that they are very promising for applications in the electromagnetic wave absorbing field. This journal is © the Partner Organisations 2014.


Yan J.,Harbin Engineering University | Fan Z.,Harbin Engineering University | Sun W.,Harbin Engineering University | Ning G.,China University of Petroleum - Beijing | And 5 more authors.
Advanced Functional Materials | Year: 2012

Hierarchical flowerlike nickel hydroxide decorated on graphene sheets has been prepared by a facile and cost-effective microwave-assisted method. In order to achieve high energy and power densities, a high-voltage asymmetric supercapacitor is successfully fabricated using Ni(OH) 2/graphene and porous graphene as the positive and negative electrodes, respectively. Because of their unique structure, both of these materials exhibit excellent electrochemical performances. The optimized asymmetric supercapacitor could be cycled reversibly in the high-voltage region of 0-1.6 V and displays intriguing performances with a maximum specific capacitance of 218.4 F g -1 and high energy density of 77.8 Wh kg -1. Furthermore, the Ni(OH) 2/graphene//porous graphene supercapacitor device exhibits an excellent long cycle life along with 94.3% specific capacitance retained after 3000 cycles. These fascinating performances can be attributed to the high capacitance and the positive synergistic effects of the two electrodes. The impressive results presented here may pave the way for promising applications in high energy density storage systems. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University | Fu B.L.,Harbin Engineering University | Yang S.Y.,Harbin Engineering University | Ma L.,Harbin Normal University
Materials Chemistry and Physics | Year: 2010

Two members of the family of orthosilicate, Li2FeSiO4 and Li2MnSiO4, are prepared by a citric acid assisted sol-gel method. As cathode materials for lithium-ion batteries, their structural, morphological and electrochemical characteristics are investigated and compared. Both cathode materials have nanoparticles with similar lattice parameters. Li2FeSiO4 has a maximum discharge capacity of 152.8 mAh g-1, and 98.3% of its maximum discharge capacity is retained after fifty cycles. However, the discharge capacity of Li2MnSiO4 fades rapidly and stabilized at about 70 mAh g-1 after twenty cycles. The electrochemical impedance and differential capacity analysis indicate that Li2MnSiO4 has larger charge transfer impedance and higher electrochemical irreversibility than Li2FeSiO4, which makes its electrochemical behaviors seriously deteriorate and leads to difference between two silicate materials. © 2009 Elsevier B.V. All rights reserved.


Xu Y.,Harbin Engineering University | Shi Q.,Harbin Engineering University | Zhu Z.,Harbin Engineering University | Shi J.,Harbin Engineering University | Shi J.,Nanjing Southeast University
Optics Express | Year: 2014

We propose a kind of planar chiral optical metamaterial consisting of two layers of connected I-shape resonators arranged by a twist angle of 90°. Numerical simulation results demonstrate that our scheme can realize a mutual polarization conversion and dual-band asymmetric transmission for linearly polarized waves in the optical regime. For the forward propagation, the x-to-y and y-to-x polarization conversions in the proposed bilayered metamaterial result from the concentric and eccentric Cshaped dimers, respectively. The current distributions of bilayered metamaterials at the resonant frequencies are presented to interpret the dualband asymmetric transmission. The polarization conversion efficiency and resonant frequencies can be modified via parametric study. © 2014 Optical Society of America.


Liu G.,Harbin Engineering University | Li S.,Harbin Engineering University | Li Y.,China Ship Development And Design Center | Chen H.,Shenyang Aeroengine Research Institute
Journal of Sound and Vibration | Year: 2013

Branched pipes of arbitrary shapes are prevalent in pipe systems. Considering fluid-structure interaction (FSI), an absorbing transfer matrix method in frequency domain for fluid-filled pipelines with any branched pipes is proposed in this paper. A dominant chain of pipeline would be selected, and the point transfer matrix of each junction on the dominant chain would be determined. Here, the point transfer matrix, representing the influence of branched pipes at the junction on the dominant pipeline, was "absorbed" by the dominant chain. Based on these, with transfer matrixes of other elements, the fluid and structure dynamics problem could be solved following the chain transfer matrix method process. Several numerical examples with different constraints are presented to illustrate the application of the proposed method. Moreover, the experiment of cross-shaped pipes with various boundary conditions was carried out. And results from the present approach were validated by measured and numerical data. Then, the forced vibrations of branched pipes were analyzed by considering the effects of various parameters, which shows the fluid pressure and vibrations can be optimized by changing the branch angles and positions. Through these examples, it is shown that the proposed method is efficient and can be used to calculate branched pipes of any shape. © 2013 Elsevier Ltd.


Meng Y.,Harbin Engineering University | Yu T.,Harbin Normal University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Journal of Materials Chemistry A | Year: 2016

The tailoring of materials into bio-inspired structures is triggering unprecedented innovations. Muscle tissue is composed of myofibrils and densely wired blood vessels; it is a perfect model for designing high-performance electrode materials that have the advantage of fast mass transport and superior durability. We design a top-down strategy as a facile approach to tailor the alluaudite Na2+2xFe2-x(SO4)3 into a muscle-like spindle. A precipitation process is employed to prepare the hydrated "top" precursor, which is subjected to dehydration and phase transformation to obtain the "down" product. The alluaudite sulfate nanoparticles closely anchor on the single-wall carbon nanotubes (SWNT), and they together aggregate into microscale particles in the shape of spindles. The Na2+2xFe2-x(SO4)3/SWNT composite as a whole copies the morphology and function of muscle tissue. Taking advantage of its 3D conductive framework and porous structure, the composite achieves fast electron/ion transport and sodium intercalation. Moreover, the single-phase reaction mechanism during sodium intercalation is beneficial to its cycling property. It exhibits such desirable electrochemical performance as an operating potential as high as ∼3.8 V and a high-rate capability, which achieves a capacity retention of 92% after 100 cycles at 5C. The muscle-inspired architecture makes electrode materials favorable for superior electrochemical performance. © The Royal Society of Chemistry 2016.


Shi J.H.,Harbin Engineering University | Shi J.H.,Nanjing Southeast University | Ma H.F.,Nanjing Southeast University | Jiang W.X.,Nanjing Southeast University | Cui T.J.,Nanjing Southeast University
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We propose a kind of stereometamaterial composed of periodic structures with twisted asymmetrical split-ring (ASR) resonators. The proposed stereometamaterial has intrinsic chirality and can be used as a multiband polarization spectral filter. Full-wave simulation and experimental results demonstrate that the stereometamaterial with the twist angle of φ=90 exhibits three ripple-free cross-polarization transmission peaks at normal incidence of plane waves. The cross-polarization transmission bands are centered at the maxima of circular dichroism, accompanied by pairs of pure circular birefringence points. In physics, the near-field electric and magnetic coupling of orthogonal ASR molecules in parallel planes contributes to the conversion of two orthogonal linear polarizations. The transmission of the proposed multiband polarization spectral filter can be engineered via the mutual twist angle and asymmetry of the ASRs and the thickness of the dielectric spacer layer and also be tuned via the angle of incidence. © 2012 American Physical Society.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University | Yang S.Y.,Harbin Engineering University | Fu B.L.,Harbin Engineering University | Ma L.,Harbin Normal University
Journal of Power Sources | Year: 2011

Attempts to dope Zn2+, Cu2+ or Ni2+ are made for Li2FeSiO4. The effects of dopant on the physical and electrochemical characteristics of Li2FeSiO4 were investigated. Zn2+ successfully entered into the lattice of Li 2FeSiO4 and induced the change of lattice parameters. Compared with the undoped Li2FeSiO4, Li2Fe 0.97Zn0.03SiO4 has higher discharge capacity, better electrochemical reversibility and lower electrode polarization. The improved electrochemical performance of Li2Fe0.97Zn 0.03SiO4 can be attributed to the improved structural stability and the enhanced lithium ion diffusivity brought about by Zn 2+ doping. However, Ni2+ and Cu2+ cannot be doped into the lattice of Li2FeSiO4. Cu and NiO are formed as impurities in the Cu- and Ni-containing samples, respectively. Compared with the undoped Li2FeSiO4, the Cu- and Ni-containing samples have lower capacities and higher electrochemical polarization. © 2010 Elsevier B.V.


Shi J.,Harbin Engineering University | Shi J.,Nanjing Southeast University | Liu X.,Harbin Engineering University | Yu S.,Harbin Engineering University | And 4 more authors.
Applied Physics Letters | Year: 2013

A bilayered chiral metamaterial is proposed and demonstrated to exhibit dual-band asymmetric transmission of linearly polarized electromagnetic waves in two opposite directions. Simulated and measured results show that the bilayered chiral metamaterial can achieve cross-polarization conversion with an efficiency of over 90 for both y- and x-polarized waves. The proposed metasurface can be regarded as an ultrathin polarization-controlled switch that is easily switched on/off by changing a linearly polarized wave to its orthogonal component. © 2013 AIP Publishing LLC.


Gao X.,Nanjing Southeast University | Gao X.,Guilin University of Electronic Technology | Hui Shi J.,Nanjing Southeast University | Hui Shi J.,Harbin Engineering University | And 5 more authors.
Applied Physics Letters | Year: 2013

We present an ultrathin dual-band plasmonic waveguide and frequency splitter experimentally based on designer surface plasmon polaritons (DSPPs) of planar composite periodic gratings. In such planar plasmonic metamaterials, the electromagnetic wave can be tightly confined around an ultrathin metallic grating, and the propagation of DSPPs strongly depends on the dispersion relation determined by the depth of groove. Based on such features, we design and fabricate an ultrathin composite grating to support two DSPP modes, which exhibit low bending loss in the bending surface plasmon polariton (SPP) waveguide. We further propose an ultrathin SPP frequency splitter by adjusting the groove depths of two branches. The experimental results are in good agreement to the numerical simulations. © 2013 AIP Publishing LLC.


Zhang H.,Harbin Engineering University | Zhu C.,Harbin Engineering University | Chen Y.,Harbin Engineering University | Gao H.,Harbin Normal University
ChemPhysChem | Year: 2014

A facial strategy is developed to fabricate a three-dimensional (3D) Fe3O4 nanorod array/graphene architecture, in which Fe3O4 nanorods with a length and diameter of about 600 and 100 nm, respectively, are grown on both surfaces of the graphene sheets. The measured electromagnetic parameters show that the 3D architecture exhibits excellent electromagnetic wave-absorption properties, that is, more than 99 % of electromagnetic wave energy can be attenuated by the 3D architecture if it is added in only 20 wt % of the paraffin matrix, as the thickness of the absorber is in the range from 2.38 to 5.00 mm. The analysis of the electromagnetic (EM) absorption mechanism reveals that the excellent EM absorption properties are related to the special 3D architecture, and therefore, the construction of graphene-based 3D heteronanostructures is effective in obtaining lightweight EM absorbers with strong absorption properties. Show EM who's boss: Three-dimensional (3D) Fe3O4 nanorod arrays/G heteronanostructures are fabricated by a facial method, and they exhibit significantly enhanced electromagnetic (EM) wave-absorption properties. Moreover, the content of the 3D heteronanostructures in a wax matrix is only 20 wt %. Thus, the presented method is very effective in fabricating lightweight EM wave absorbents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University | Fu B.L.,Harbin Engineering University | Yang S.Y.,Harbin Engineering University | Ma L.,Harbin Normal University
Electrochimica Acta | Year: 2010

Cr-doped Li2FeSiO4 was prepared by a sol-gel method. The effects of Cr doping on the characteristics of Li2FeSiO 4 were carefully investigated. Compared with the XRD pattern of the Li2FeSiO4 sample, the XRD patterns of the Cr-doped samples have no extra reflections. This indicates that Cr enters the structure of Li2FeSiO4 rather than forming impurities. As indicated by the charge-discharge measurements, the highest capacity is obtained by 3% Cr doping. The particle size of the Li2Fe0.97Cr 0.03SiO4 sample was smaller than that of the Li 2FeSiO4 sample, and the BET surface area of the Li 2Fe0.97Cr0.03SiO4 sample was more than twice as high as that of the Li2FeSiO4 sample. Compared with the Li2FeSiO4 sample, the Li 2Fe0.97Cr0.03SiO4 sample shows faster activation, higher reversible capacity, and better rate capability, which can be attributed to the smaller particle size and larger surface area as well as the crystal defects induced by Cr doping. © 2010 Elsevier Ltd All rights reserved.


Qu Z.,Harbin Normal University | Qu Z.,Harbin Engineering University | Wu R.,Harbin Engineering University | Zhan H.,Harbin Engineering University | Zhang M.,Harbin Engineering University
Journal of Alloys and Compounds | Year: 2012

As-cast Mg-9Li-3Al(LA93) and Mg-9Li-6Al(LA96) alloys were prepared under the ambient of pure argon, and the effect of solution treatment and room temperature (RT) aging on the microstructure and microhardness of the alloys were investigated. The results show that the main phase compositions of the two alloys both consist of α(Mg), β(Li), AlLi phase, besides that there is θ(MgLi 2Al) phase in LA96. After solid solution treatment, AlLi phase can completely be dissolved into the matrix, while θ phase is not fully dissolved into the matrix. In LA93 and LA96 alloys, AlLi phase precipitates from matrix during the 24 h RT aging. When the aging time increases to 48 h, more AlLi phase turns up and appears to aggregate which results in the decrease of hardness, and the transformation of θ phase into the equilibrium phase (AlLi) in LA96 also causes the hardness decrease. © 2012 Elsevier B.V. All rights reserved.


Fan Z.,Harbin Engineering University | Yan J.,Harbin Engineering University | Wei T.,Harbin Engineering University | Zhi L.,National Center for Nanosciences and Technology of China | And 3 more authors.
Advanced Functional Materials | Year: 2011

Asymmetric supercapacitor with high energy density has been developed successfully using graphene/MnO2 composite as positive electrode and activated carbon nanofibers (ACN) as negative electrode in a neutral aqueous Na2SO4 electrolyte. Due to the high capacitances and excellent rate performances of graphene/MnO2 and ACN, as well as the synergistic effects of the two electrodes, such asymmetric cell exhibits superior electrochemical performances. An optimized asymmetric supercapacitor can be cycled reversibly in the voltage range of 0-1.8 V, and exhibits maximum energy density of 51.1 Wh kg-1, which is much higher than that of MnO2//DWNT cell (29.1 Wh kg-1). Additionally, graphene/MnO2//ACN asymmetric supercapacitor exhibits excellent cycling durability, with 97% specific capacitance retained even after 1000 cycles. These encouraging results show great potential in developing energy storage devices with high energy and power densities for practical applications. A novel asymmetric supercapacitor based on graphene/MnO2 and activated carbon nanofibers (ACN) as the positive and negative electrodes, respectively, has been developed in aqueous Na2SO4 electrolyte solution. More interestingly, the asymmetric supercapacitor exhibits a maximum energy density of 51.1 Wh kg-1 and excellent cycling durability, with 97% specific capacitance retained even after 1000 cycles. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University | Wu Y.X.,Harbin Normal University | Zhao B.D.,Harbin Normal University
Journal of Electroanalytical Chemistry | Year: 2014

Partial substitution of Mn/Si with V, Cr or Al is employed to modify Li2MnSiO4 nanoparticles. The dependence of the physical and chemical properties on the substitution strategy is clarified. In comparison with partial substitution of Mn, partial substitution of Si with the same substituent usually results in larger lattice volume, lower O-Si-O bridging linkage and higher specific surface area with smaller particle size, which contributes to lower charge transfer resistance and higher lithium ion diffusion coefficient. Li2.05MnSi0.95Al0.05O4 delivers a discharge capacity as high as 108 mA h g-1 at the current density of 660 mA g-1. However, partial substitution of Si leads to faster capacity fading in comparison with partial substitution of Mn with the same substituent, which can be attributed to the absence of the pillar effect when Si is substituted. Substitution of Si with Al, V or Cr is a promising strategy to break through the insulation effect of (SiO4) 4- polyanion and thus improves the high rate capability of Li 2MnSiO4. © 2014 Elsevier B.V. All rights reserved.


Deng C.,Harbin Normal University | Zhang S.,Harbin Engineering University | Dong Z.,Harbin Normal University | Shang Y.,Harbin Normal University
Nano Energy | Year: 2014

1D nanostructured sodium vanadium oxide, i.e. Na2V6O16·nH2O, was introduced as a novel anode material for aqueous sodium ion batteries. A simple hydrothermal method is employed to prepare bundles of straight nanobelts whose crystals grow along the (010) direction. In each bundle, most nanobelts are aligned along the same direction. Sodium vanadium oxide hydrate has a layered structure, and that sodium ions are located at the interstices between layers. The solid-state diffusion coefficient of sodium ion in the bulk of Na2V6O16·nH2O is in the order of magnitude of 10-14cmS-1. The discharge/charge capacity fades quickly in the initial few cycles upon galvanostatic cycling. It is revealed by ex-situ XRD analyses that this fast capacity fading can be attributed to the irreversible phase transition which mainly occurs in the first discharge. A full aqueous sodium ion battery was built using Na2V6O16·nH2O as anode and Na0.44MnO2 as cathode. Although its charge capacity fades quickly in the initial few cycles and stabilizes in the following cycles, its discharge capacity is comparatively stable upon cycling. © 2014.


Zhang L.,Harbin Engineering University | Zhang L.,Northwestern Polytechnical University | Zhang K.,Harbin Engineering University | Zhang K.,University of Turku
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

This brief investigates the controllability and observability of Boolean control networks with (not necessarily bounded) time-variant delays in states. After a brief introduction to converting a Boolean control network to an equivalent discrete-time bilinear dynamical system via the semi-tensor product of matrices, the system is split into a finite number of subsystems (constructed forest) with no time delays by using the idea of splitting time that is proposed in this brief. Then, the controllability and observability of the system are investigated by verifying any so-called controllability constructed path and any so-called observability constructed paths in the above forest, respectively, which generalize some recent relevant results. Matrix test criteria for the controllability and observability are given. The corresponding control design algorithms based on the controllability theorems are given. We also show that the computing complexity of our algorithm is much less than that of the existing algorithms. © 2012 IEEE.


Zhang L.J.,Harbin Engineering University | Zhang K.Z.,Harbin Engineering University | Zhang K.Z.,University of Turku
Science China Information Sciences | Year: 2013

This paper investigates the controllability of time-variant Boolean control networks (BCNs). For the time-variant BCNs, a necessary and sufficient condition for the controllability is given, and a control design algorithm is presented. For a BCN with finite memories, an equivalent transformation to a time-variant BCN is constructed. Then a necessary and sufficient condition for the controllability and a control design algorithm are obtained. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.


Wang J.-W.,Beihang University | Wu H.-N.,Beihang University | Guo L.,Beihang University | Luo Y.-S.,Harbin Engineering University
Fuzzy Sets and Systems | Year: 2013

This paper investigates the problem of robust H ∞ fuzzy control for a class of uncertain nonlinear Markovian jump systems with time-varying delay. The class of systems under consideration is described by the Takagi-Sugeno fuzzy model. The goal of the paper is to design a mode-dependent fuzzy state-feedback controller such that the closed-loop system is stochastically stable with a prescribed H ∞ performance of disturbance attenuation for all admissible parameter uncertainties. In order to obtain a less conservative control design, a new stochastic Lyapunov-Krasovskii functional is first constructed by decomposing the delay interval into multiple equidistant subintervals. Then, by employing this functional, a delay decomposition approach to the design of robust H ∞ fuzzy controllers is developed in terms of linear matrix inequalities. Finally, two examples are given to illustrate the merit and usability of the proposed design method. © 2012 Elsevier B.V.


Fan Z.,Harbin Engineering University | Yan J.,Harbin Engineering University | Zhi L.,National Center for Nanosciences and Technology of China | Zhang Q.,Tsinghua University | And 5 more authors.
Advanced Materials | Year: 2010

Three-dimensional carbon nanotube/graphene sandwich structures with CNT pillars grown in between the graphene layers have been developed by chemical vapor deposition. The special structure endows the high-rate transportation of electrolyte ions and electrons throughout the electrode matrix, resulting in excellent electrochemical performance of this hybrid material. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Tan L.,Harbin Engineering University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Journal of Power Sources | Year: 2014

Lithium iron pyrophosphate has drawn great attention because of its interesting physical and electrochemical properties, whereas its high rate capability is far from satisfactory. We synthesize nano-Li2FeP2O7/C with hierarchical pore via a low cost method which uses iron powder instead of Vitamin C as the reducing agent. The hierarchical pore is constructed through a "combustion" mechanism according to the thermogravimetric and morphological characterizations. The phase-pure nanoparticles of Li2FeP2O7 are embedded in the three-dimensional network of amorphous carbon. The hierarchical pore together with the two-dimensional diffusion channel of lithium in Li2FeP2O7 is beneficial to lithium diffusion capability which is evaluated by the lithium diffusion coefficients calculated from the results of GITT measurements. The fast lithium intercalation chemistry facilitates the reversible de/intercalation of lithium, resulting in the high cycling stability and rate-capability. After 100 cycles at the current density of 1C, 93.8% of the initial capacity is retained. The discharge capacity is 62.1 mAh g-1 at the current density of 4C. Therefore, the hierarchically porous nano-Li2FeP2O7/C is a promising cathode material for advanced rechargeable lithium ion battery. © 2014 Elsevier B.V. All rights reserved.


Feng Ma H.,Nanjing Southeast University | Hui Shi J.,Nanjing Southeast University | Hui Shi J.,Harbin Engineering University | Geng Cai B.,Nanjing Southeast University | Jun Cui T.,Nanjing Southeast University
New Journal of Physics | Year: 2012

We demonstrate theoretically and experimentally total transmission and super reflection which are realized by anisotropic zero-index materials (AZIMs). We show that total transmission will be observed when using a rectangular perfectly magnetic conductor (PMC)-coated object sandwiched by two AZIM slabs, which has the properties of μrx = 0 (in the normal direction to the wavefronts) and μry = εrz = 1 for transverse-electric polarized incident waves. When the object is coated with a perfectly electric conductor (PEC), however, the incident waves will be totally reflected by the finite-sized object in the way of an infinite PEC plane, generating a super reflection. Closed-form formulas are derived to explain the physical mechanisms of total transmission and super reflection, which agree with the full-wave numerical simulations perfectly. Experimental samples of AZIM and PMC are designed, fabricated and measured in the microwave frequency, which show good transparent and super-reflecting effects. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


Sun F.,Harbin Engineering University | Tang L.-J.,China Ship Development And Design Center
Kongzhi yu Juece/Control and Decision | Year: 2013

In order to select the appropriate filtering method from the UKF and CKF for the different dimensions nonlinear systems estimation, the two filters are analyzed and compared through the Taylor expansion of function and the numerical stability. Due to the different dimension, the captured high-order item degree of function Taylor expansion and the numerical stability are different to appear different filter precisions, so that the filter choice ways of different dimension are acquired. Simulation results show the correctness of with the theoretical analysis.


Lu X.,Harbin Engineering University | Shang Y.,Harbin Normal University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Electrochimica Acta | Year: 2015

Poor ion transport and rate capability are the main challenges for LiV3O8 as cathode material for lithium ion batteries.Here we report a novel strategy for enhancing lithium ion transport by building superionic pathways on the surface of Li0.85Na0.15V3O8 nanosheet.The two-dimensional Li0.85Na0.15V3O8 nanoparticle with an ion conductive layer of LixV2O5 on its surface is constructed by a modified sol-gel strategy with carefully controlled sodium incorporation and elements stoichiometry.Ultrathin LixV2O5 surface layer not only provides facile pathways for lithium migration,but also increases the structure stability during cycling.The LixV2O5-Li0.85Na0.15V3O8 composite displays good high rate capability of 172.3 mAh g-1 at 5C and excellent cycling stability of 98.9%over fifty cycles.This superior electrochemical property is attributed to the occupation of lithium site by Na+ in LiV3O8 host crystals and the surface superionic pathways of LixV2O5 phase. Therefore, the advantages of both high ion transport and the structure stabilization in present study put forward a new strategy for achieving high-performance LiV3O8 electrode material with tailored nanoarchitecture. © 2014 Elsevier Ltd. All rights reserved.


Gai S.,Harbin Engineering University | Qu F.,Harbin Normal University | Yang P.,Harbin Engineering University
ACS Applied Materials and Interfaces | Year: 2013

A novel bifunctional (fluorescent, mesoporous) hollow sphere was prepared by coating luminescent YBO3:Eu3+ nanoparticles onto uniform hollow mesoporous silica spheres (HMSs), derived from an etching strategy using spherical Fe3O4 as templates. The composites exhibit typical mesoporous shells, large interior space, high surface area, and well dispersed nanospheres with controlled size. In addition, the textural properties including the specific surface and pore volume can be easily altered by simply tuning of the spherical Fe3O4 cores. Upon ultraviolet (UV) excitation, the composite shows the characteristic 5D0-7F1-4 red emission lines of Eu3+ even after loading of the model drug. The composite with a large surface area and cavity was used as the host for loading the anticancer drug doxorubicin hydrochloride (DOX). It is observed that the multifunctional composites exhibit an obvious sustained release property and released in texture- and pH-sensitive patterns. Particularly, the down-conversion (DC) fluorescence intensity of the bifunctional vehicle increases with the release of drug molecules, making it possible to track the position and the drug release amount of the drug carrier system and to detect them by the change of fluorescence intensity. © 2013 American Chemical Society.


Wang C.,China Ship Development And Design Center | Wang S.,China Ship Development And Design Center | Wang H.,China Ship Development And Design Center | Gao P.,Harbin Engineering University
Annals of Nuclear Energy | Year: 2014

The effect of additional inertial forces on the flow rate pulsation in rolling motion condition is theoretically and experimentally studied, and the essential influencing factors that affect the flow pulsation behavior are clarified. Both the theoretical and experimental results indicate that the relative pulsation amplitude of flow rate increases with the driving head increasing, however, it decreases with the increase of experimental loop friction resistance. Furthermore, the investigation results also indicate that the effect of additional inertial force can be neglected and the flow rate will not present significant pulsation when the intensity of driving force is 10 times larger than the additional inertial force. The pulsation intensity of flow rate in rolling motion condition depends on the relative quantity of driving head, friction resistance and additional inertial acceleration. © 2013 Published by Elsevier Ltd. All rights reserved.


Wang C.,China Ship Development And Design Center | Li X.,China Ship Development And Design Center | Wang H.,China Ship Development And Design Center | Gao P.,Harbin Engineering University
Progress in Nuclear Energy | Year: 2014

Friction and heat transfer characteristics of pulsating flow induced by rolling motion are experimentally studied. A series of single-phase forced circulation flow experiments are conducted in a vertical narrow channel. In the present study the flow rate is adjusted through control the impeller rotator speed of the pump. The results show that the flow rate pulsation simultaneously with the rolling motion and the relative amplitude of the flow rate pulsation decreases with the increasing flow rate. Accordingly, the relationships between the relative pulsation amplitude of friction factor, heat transfer coefficient and flow rate are classified. Therefore, the correlations have been developed to calculate the friction and heat transfer coefficient based on the relative pulsation amplitude of the flow rate. © 2013 Elsevier Ltd. All rights reserved.


Zhao B.,Harbin Normal University | Wang Q.,Harbin Normal University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Journal of Materials Chemistry A | Year: 2015

The three-dimensional (3D) hierarchical porous structure is ideal for constructing high-performance electrode materials and offers advantages such as large surface area, stable structural integrity and efficient ionic transport. In this report, we prepared a novel wafer-like 3D porous structured NaTi2(PO4)3/C by a facile self-assembled strategy. The NaTi2(PO4)3 crystal was not only coated by a nanoscale carbon layer but was also embedded in a microscale carbon network, which self-assembled into a secondary particle in a plate-like shape. The hierarchical carbon in the plate-like particle constitutes a 3D porous framework with a bicontinuous electronic conductive skeleton, showing a wafer-like structure. When used as an anode in an aqueous system, the wafer-like composite exhibited better sodium intercalation kinetics and enhanced high-rate capability than nonporous samples. Moreover, a full aqueous rechargeable sodium battery was fabricated using the wafer-like NaTi2(PO4)3 as the anode and Na0.44MnO2 as the cathode. The cell exhibited superior high rate property and an ultralong-life performance, which delivered 64% capacity at 30 C and retained 67% capacity after 400 cycles at alternate 50 and 5 C. In view of the highly efficient electron/ion transport pathways and robust structure stability, the wafer-like structure is put forward as a new strategy for nanoarchitecture tailoring to achieve high-performance electrodes. © The Royal Society of Chemistry 2015.


Wang Q.,Harbin Normal University | Zhao B.,Harbin Normal University | Zhang S.,Harbin Engineering University | Gao X.,Northeast Agricultural University | Deng C.,Harbin Normal University
Journal of Materials Chemistry A | Year: 2015

Tailoring materials into a hierarchical porous micro/nanostructure offers unprecedented opportunities in the utilization of their functional properties. Particularly, it is crucial for the electrode materials to realize high-performance because of the advantages such as large surface area, superior structure stability and short ion transport pathway. Here we report the design of a new architecture, named "honeycomb-type hierarchical porous microball", for Na3V2(PO4)3 by a facile one-pot synthesis. The network between nanovoids is formed by in situ carbonization of surfactants (CTAB) along with the crystallization of Na3V2(PO4)3, which results in the hierarchical porous Na3V2(PO4)3 skeleton with a surface conductive layer. The prepared Na3V2(PO4)3/C composite consists of spherical particles filled with hierarchical pores and interconnective nanochannels, resulting in the honeycomb-type architecture. It not only enables easier electrolyte penetration, but also provides a high-efficiency electron/ion transport pathway for fast sodium intercalation. Both the GITT and EIS results demonstrate the improved sodium diffusion capability and decreased electrochemical resistance for the honeycomb-structured microball in comparison to the microsized nonporous reference samples. Moreover, it also delivers superior high rate capability and cycling stability, which retains 93.6% of the initial capacity after 200 cycles at the 1 C rate. Even at 20 C, it still delivers a high capacity of 80.2 mA h g-1 corresponding to 71% of the capacity. Given the superior ion intercalation kinetics and excellent structure stability, the honeycomb-type structure puts forward a new strategy to develop high-performance polyanion-based materials for low-cost and high-power "rocking-chair" batteries. © The Royal Society of Chemistry 2015.


Zhao B.,Harbin Normal University | Lin B.,Harbin Normal University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Nanoscale | Year: 2015

Hollow micro/nano-arrays have attracted tremendous attention in the field of energy conversion and storage, but such structures usually compromise the volumetric energy density of the electrode materials. Frogspawn consists of a spawn core and a transparent jelly shell organized in a hierarchical porous array, which exhibits superior mechanical strength and high-efficiency oxygen permeability. It can be used as a model for designing a new high-performance electrode material, which has advantages such as a high surface area, fast mass transport and superior durability. Herein, we report a frogspawn-like NaTi2(PO4)3/C array prepared by a facile preform impregnation strategy. The framework is formed by a hollow carbon sphere connected by the NaTi2(PO4)3/C skeleton, and its hollow is filled with the NaTi2(PO4)3 nanospheres. The whole hierarchical porous three-dimensional array copies the structure of a frogspawn. This unique structure not only enables easy electrolyte percolation and fast electron/ion transport, but also enhances the reversible capacity and cycling durability. When it is applied as an anode of the aqueous sodium ion battery, it exhibits favorable high rate capability and superior cycling stability, and retains 89% of the initial capacity after two thousand cycles at 20 C. Moreover, the full cell using the frogspawn-inspired NaTi2(PO4)3-C as the anode and Na0.44MnO2 as the cathode is capable of ultralong cycling up to one thousand cycles at alternate 10 and 60 C, which is among the best of state-of-the-art aqueous sodium ion systems. Therefore, the frogspawn-inspired architecture provides a new strategy to the tailored design of polyanion materials for high-power applications. © 2015 The Royal Society of Chemistry.


Fan Z.-J.,Harbin Engineering University | Kai W.,Harbin Engineering University | Yan J.,Harbin Engineering University | Wei T.,Harbin Engineering University | And 5 more authors.
ACS Nano | Year: 2011

The synthesis of graphene nanosheets from graphite oxide typically involves harmful chemical reductants that are undesirable for most practical applications of graphene. Here, we demonstrate a green and facile approach to the synthesis of graphene nanosheets based on Fe reduction of exfoliated graphite oxide, resulting in a substantial removal of oxygen functionalities of the graphite oxide. More interestingly, the resulting graphene nanosheets with residual Fe show a high adsorption capacity of 111.62 mg/g for methylene blue at room temperature, as well as easy magnetic separation from the solution. This approach offers a potential for costeffective, environmentally friendly, and large-scale production of graphene nanosheets. © 2011 American Chemical Society.


Lv T.T.,Harbin Engineering University | Zhu Z.,Harbin Engineering University | Zhu Z.,Nanjing Southeast University | Shi J.H.,Harbin Engineering University | And 4 more authors.
Optics Letters | Year: 2014

We demonstrate a multiband background-free terahertz (THz) switch in photoactive chiral metamaterial using polarization conversion. Orthogonal arrangement of two asymmetrical split-ring apertures allows a high polarization conversion efficiency and low copolarization transmission. The chiral metamaterial embedded with photoactive silicon promises a dynamic control on cross-polarization transmission and thus enables an efficient background-free THz switch. The on/off state of THz metamaterial switching can be efficiently controlled by an optical pump. The realization of a cross-polarization THz switch provides a new mechanism of mode switching to control THz wave propagation and will be a promising candidate for polarization devices. © 2014 Optical Society of America.


Long C.,Harbin Engineering University | Chen X.,Harbin Engineering University | Jiang L.,Harbin Engineering University | Zhi L.,National Center for Nanosciences and Technology of China | Fan Z.,Harbin Engineering University
Nano Energy | Year: 2015

Two-dimensional (2D) porous graphene-based materials such as graphene nanomesh, activated graphene and curved graphene, possess high gravimetric performances due to their high surface area and short ion transport path. However, their poor volumetric performances come from low density and/or high pore volume of the electrode materials, as well as their high manufacturing cost, which would limit their further applications. In this work, densely porous graphene-like carbon (PGC) materials were greenly synthesized through hydrothermal treatment of fungus (Auricularia) and subsequent carbonization process. Layer-stacking PGC derived from cell walls of fungus has high surface area (1103m2g-1), high bulk density (about 0.96g cm-3), and hierarchically interconnected porous framework, which can provide more storage sites and short transport paths for electrolyte ions, and enhance the overall conductivity of the electrode. As a result, the PGC electrode shows ultra-high volumetric capacitance of 360F cm-3 and excellent cycling stability with 99% capacitance retention after 10000 cycles. More importantly, the as-assembled symmetric supercapacitor delivers superior volumetric energy density of 21WhL-1 and excellent cycling stability (96% specific capacitance retention after 10000 cycles). These exciting results suggest a low-cost and environmentally friendly design of electrode materials for high volumetric-performance supercapacitors. © 2014 Elsevier Ltd.


Meng Y.,Harbin Engineering University | Zhang S.,Harbin Engineering University | Deng C.,Harbin Normal University
Journal of Materials Chemistry A | Year: 2015

Sulfate-based (SO42-) polyanionic materials with low cost and ionic-conduction break fresh ground for "rocking-chair" systems. But the high moisture sensitivity and limited conductivity led to their poor crystal stability and inferior alkaline-ion intercalation chemistry. Here we report the design of graphene-based sandwich-type nanoarchitecture for sulfate. The three-dimensional graphene-based network not only provides continuous electron/ion pathways for fast intercalation kinetics, but also effectively protects the crystal structure from deterioration to depress moisture sensitivity. As a case study, the hydrated sulfate (Na2Fe(SO4)2·2H2O)-graphene composite with a sandwich-type structure is prepared by a facile low-temperature synthesis. The depressed moisture sensitivity of hierarchical graphene-Na2Fe(SO4)2·2H2O compared to the pristine one is demonstrated by comparing their hydration process, and moreover, a shell-core hydration mechanism is disclosed. The hierarchical composite exhibits improved electronic conductivity and better sodium-lithium insertion capability than the pristine one. It delivers a reversible capacity of 72 and 69 mA h g-1 with redox potentials of 3.415/3.234 V (vs. Na+/Na) and 3.579/3.483 V (vs. Li+/Li) in sodium and lithium intercalation systems, respectively. Moreover, it also exhibits superior high rate capabilities and good cycling stability, which delivers 81% (for sodium) and 70% (for lithium) of the capacity at a 5 C rate. Therefore, the hierarchical sandwich-type architecture is favorable to realizing superior electrochemical performance for the sulfate, which presents a significant step forward in the development of low-cost large-scale batteries. This journal is © The Royal Society of Chemistry 2015.


Feng Ma H.,Nanjing Southeast University | Hui Shi J.,Nanjing Southeast University | Hui Shi J.,Harbin Engineering University | Xiang Jiang W.,Nanjing Southeast University | Jun Cui T.,Nanjing Southeast University
Applied Physics Letters | Year: 2012

We experimentally demonstrate that the guiding waves can be perfectly bended and transmitted by using anisotropic zero-index materials (AZIMs). In our experiment, the split-ring resonators are used to realize AZIMs, whose permeability component along the wave propagating direction is designed as zero. Meanwhile, metal patches are designed to realize the artificial magnetic conductors as the boundaries of waveguide. The electric-field distributions are measured by two-dimensional near-field scanning apparatus in the microwave frequency, which show good bending performance as expected by simulations. © 2012 American Institute of Physics.


Dai L.,Harbin Engineering University | Yang T.,Harbin Engineering University | Du J.,Harbin Engineering University | Li W.L.,Wayne State University | Brennan M.J.,São Paulo State University
Applied Acoustics | Year: 2013

In this paper, an exact series solution for the vibration analysis of circular cylindrical shells with arbitrary boundary conditions is obtained, using the elastic equations based on Flügge's theory. Each of the three displacements is represented by a Fourier series and auxiliary functions and sought in a strong form by letting the solution exactly satisfy both the governing differential equations and the boundary conditions on a point-wise basis. Since the series solution has to be truncated for numerical implementation, the term "exactly satisfying" should be understood as a satisfaction with arbitrary precision. One of the important advantages of this approach is that it can be universally applied to shells with a variety of different boundary conditions, without the need of making any corresponding modifications to the solution algorithms and implementation procedures as typically required in other techniques. Furthermore, the current method can be easily used to deal with more complicated boundary conditions such as point supports, partial supports, and non-uniform elastic restraints. Numerical examples are presented regarding the modal parameters of shells with various boundary conditions. The capacity and reliability of this solution method are demonstrated through these examples. © 2012 Elsevier Ltd. All rights reserved.


Fan Z.,Harbin Engineering University | Yan J.,Harbin Engineering University | Ning G.,China University of Petroleum - Beijing | Wei T.,Harbin Engineering University | And 2 more authors.
Carbon | Year: 2013

Porous graphene obtained by chemical vapor deposition (CVD) using porous MgO sheets as template is demonstrated to exhibit a high reversible capacity (1723 mAh g-1), excellent high-rate capability and cycling stability for Li-ion batteries. The simple CVD approach offers a new way for large-scale production of porous graphene materials for energy storage. © 2013 Elsevier Ltd. All rights reserved.


Zhu X.,Zhejiang GongShang University | Yuan L.,Harbin Engineering University
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2011

An effective linking and coupling method for single core single mode fiber (SMF) and capillary optical fiber is proposed. Two types of capillary optical fiber which have different structures are investigated. By splicing and tapering at the fusion point of single mode fiber and capillary optical fiber, an effective bi-tapered fiber coupling technique is implemented. The coupling mechanism and the transmission properties are studied and compared. The theoretical prediction is confirmed by the experimental results. The coupling approach is simple and efficiency.


Jia J.,Harbin Engineering University | Abudula A.,Hirosaki University | Wei L.,Jilin University | Sun B.,Harbin Engineering University | Shi Y.,Harbin Engineering University
Renewable Energy | Year: 2015

An integrated process of biomass gasification and solid oxide fuel cells (SOFC) is investigated using energy and exergy analyses. The performance of the system is assessed by calculating several parameters such as electrical efficiency, combined heat and power efficiency, power to heat ratio, exergy destruction ratio, and exergy efficiency. A performance comparison of power systems for different gasification agents is given by thermodynamic analysis. Exergy analysis is applied to investigate exergy destruction in components in the power systems. When using oxygen-enriched air as gasification agent, the gasifier reactor causes the greatest exergy destruction. About 29% of the chemical energy of the biomass is converted into net electric power, while about 17% of it is used to for producing hot water for district heating purposes. The total exergy efficiency of combined heat and power is 29%. For the case in which steam as the gasification agent, the highest exergy destruction lies in the air preheater due to the great temperature difference between the hot and cold side. The net electrical efficiency is about 40%. The exergy combined heat and power efficiency is above 36%, which is higher than that when air or oxygen-enriched air as gasification agent. © 2015 Elsevier Ltd.


Yang W.,Harbin Engineering University | Gao Z.,Harbin Engineering University | Gao Z.,University of Virginia | Ma J.,Harbin Engineering University | And 3 more authors.
Journal of Materials Chemistry A | Year: 2014

A hierarchical NiCo2O4@NiO core-shell nanowire hetero-nanostructure has been successfully anchored on a carbon cloth conductive substrate by the stepwise design to fabricate the NiCo2O 4@NiO/CC composite for a high-performance flexible all-solid-state electrochemical capacitor. The assembled capacitor exhibits improved pseudocapacitive performance because of the synergetic effect of each component. Impressively, based on the total mass of active material on both electrodes, a high gravimetric capacitance of 1792 F g-1 at 5 mA cm-2 is achieved for the final NiCo2O4@NiO/CC flexible capacitor, along with excellent rate capability and cycle performance (with the capacity retention of 87.5% after 5000 cycling). The outstanding electrochemical performances are attributed to its superstructure with significantly enhanced active-surface area, favorable morphological stability and convenient ion transport paths. These results clearly present a cost-effective and alterable method for fabrication of various core-shell nanostructures on flexible conductive substrates, which may bring new design opportunities of device configuration for energy-storage applications in future wearable electronics. © 2014 The Royal Society of Chemistry.


Yan J.,Harbin Engineering University | Sun W.,Harbin Engineering University | Wei T.,Harbin Engineering University | Zhang Q.,Tsinghua University | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

Hierarchical porous Ni(OH) 2 nanoflakes anchored on graphene sheets has been fabricated by a facile chemical precipitation approach. The as-prepared Ni(OH) 2/graphene composite as a electrode material for supercapacitors displays ultrahigh specific capacitance, superior cycling performance, and excellent rate capability. A maximum specific capacitance of 2194 F g -1 could be obtained at 2 mV s -1 in 6 M KOH aqueous solution. Meanwhile, the electrode exhibits excellent long cycle life along with 95.7% specific capacitance retained after 2000 cycle tests. Such composite is a highly promising candidate as electrode material for broad applications in energy conversion/storage systems. © 2012 The Royal Society of Chemistry.


Zhu X.,China University of Petroleum - Beijing | Ning G.,China University of Petroleum - Beijing | Ma X.,China University of Petroleum - Beijing | Fan Z.,Harbin Engineering University | And 3 more authors.
Journal of Materials Chemistry A | Year: 2013

Here, we report a novel Co3O4-graphene hybrid electrode material with high density Co3O4 nanoparticles (NPs) in a size range of 2-3 nm confined in a few-layered porous graphene nanomesh (PGN) framework driven by an electrochemical process. Raman spectra indicate that Co species preferentially anchor on the defective sites of the PGN, which results in markedly reduced irreversible Li storage and therefore significantly enhanced coulombic efficiency. The ultra-small Co 3O4 NPs provide a large surface area and a short solid-state diffusion length, which is propitious to achieving a high Li ion capacity at high rate. Also, the few-layered graphene network with high electronic conductivity not only permits easy access to the high surface area of the Co3O4 NPs for the electrolyte ions, but also serves as a reservoir for high capacity Li storage. As a result, the Co 3O4-PGN composite layers deliver an ultra-high capacity (1543 mA h g-1 at 150 mA g-1) and excellent rate capability (1075 mA h g-1 at 1000 mA g-1) with good cycling stability. This journal is © The Royal Society of Chemistry.


Yang W.,Harbin Engineering University | Gao Z.,Harbin Engineering University | Gao Z.,University of Virginia | Ma J.,Harbin Engineering University | And 3 more authors.
Electrochimica Acta | Year: 2013

Nano-structured cobalt oxides (Co3O4) with various morphologies (sheet-like, herbs-like and net-like) have been in situ synthesized on the surface of nickel foam via a facile solvothermal method. Ethanol, ethylene glycol (EG) and glycerol (GR) were used to investigate the effects of solvent on the size and morphology of nanocrystals in detail. The possible formation mechanisms have been proposed that the dielectric constants and viscosity of solvents is speculated to be the main factor to determine the morphology of Co3O4 crystal. Applied for supercapacitor, the fabricated Co3O4 electrodes show the desired properties of macroporosity, allowing facile electrolyte flow and fast electrochemical reaction kinetics. Results show that the nanonet-like Co 3O4 electrode synthesized in glycerol solvothermal condition has the highest capacitance (1063 F/g at a discharge current density of 10 mA/cm2), and good rate capability, excellent electrochemical stability (90.8% retention after 1000 cycles). The enhanced electrochemical performance is attributed to the open and ultrathin nanostructure of net-like Co3O4 electrode, which facilitates the electron transport. The findings in this work demonstrate the importance of solvents used for solvothermal reaction, and are meaningful in understanding the self-assembly process of various Co3O4 nanostructures. © 2013 Elsevier Ltd. All rights reserved.


Zhu C.,China Academy of Launch Vehicle Technology | Ni J.,Harbin Engineering University
Proceedings - 6th International Conference on Internet Computing for Science and Engineering, ICICSE 2012 | Year: 2012

Differential Evolution (DE) is one of the current best evolutionary algorithms. It becomes important in many fields such as evolutionary computing and intelligent optimization. At present, DE has successfully been applied to diverse domains of science and engineering, such as signal processing, neural network optimization, pattern recognition, machine intelligence, chemical engineering and medical science. However, almost all the DE-related evolutionary algorithms still suffer from the problems such as premature convergence, slow convergence rate and difficult parameter setting. To overcome these drawbacks, we propose a novel Cloud Model-Based Differential Evolution Algorithm (CMDE) in which the pheromone and the sensitivity model of free search algorithm replaces the traditional roulette wheel selection model. The model incorporates Opposition-Based Leaning (OBL) to present an improved artificial bee colony algorithm. Experimental results verify the superiority of CMDE is over several state-of-the-art evolutionary optimizers. © 2012 IEEE.


Du J.,Harbin Engineering University | Li W.L.,Wayne State University | Liu Z.,Harbin Engineering University | Yang T.,Harbin Engineering University | Jin G.,Harbin Engineering University
Journal of Sound and Vibration | Year: 2011

An analytical method is derived for determining the vibrations of two plates which are generally supported along the boundary edges, and elastically coupled together at an arbitrary angle. The interactions of all four wave groups (bending waves, out-of-plane shearing waves, in-plane longitudinal waves, and in-plane shearing waves) have been taken into account at the junction via four types of coupling springs of arbitrary stiffnesses. Each of the transverse and in-plane displacement functions is expressed as the superposition of a two-dimensional (2-D) Fourier cosine series and several supplementary functions which are introduced to ensure and improve the convergence of the series representation by removing the discontinuities that the original displacement and its derivatives will potentially exhibit at the edges when they are periodically expanded onto the entire xy plane as mathematically implied by a 2-D Fourier series. The unknown expansions coefficients are calculated using the RayleighRitz procedure which is actually equivalent to solving the governing equation and the boundary and coupling conditions directly when the assumed solutions are sufficiently smooth over the solution domains. Numerical examples are presented for several different coupling configurations. A good comparison is observed between the current results and the FEA models. Although this study is specifically focused on the coupling of two plates, the proposed method can be directly extended to structures consisting of any number of plates. © 2010 Elsevier Ltd. All rights reserved.


Li X.,Nanjing University | Fang J.,Sun Yat Sen University | Liu G.,Harbin Engineering University | Zhang S.,Nanjing University | And 2 more authors.
Water Research | Year: 2014

Hydrated electron (eaq -), which is listed among the most reactive reducing species, has great potential for removal and detoxification of recalcitrant contaminants. Here we provided quantitative insight into the availability and conversion of eaq - in a newly developed sulfite/UV process. Using monochloroacetic acid as a simple eaq --probe, the eaq --induced dehalogenation kinetics in synthetic and surface water was well predicted by the developed models. The models interpreted the complex roles of pH and S(IV), and also revealed the positive effects of UV intensity and temperature quantitatively. Impacts of humic acid, ferrous ion, carbonate/bicarbonate, and surface water matrix were also examined. Despite the retardation of dehalogenation by electron scavengers, the process was effective even in surface water. Efficiency of the process was discussed, and the optimization approaches were proposed. This study is believed to better understand the eaq --induced dehalogenation by the sulfite/UV process in a quantitative manner, which is very important for its potential application in water treatment. © 2014 Elsevier Ltd.


Ning G.,China University of Petroleum - Beijing | Fan Z.,Harbin Engineering University | Wang G.,China University of Petroleum - Beijing | Gao J.,China University of Petroleum - Beijing | And 2 more authors.
Chemical Communications | Year: 2011

Graphene that had nanomeshes, only one to two graphene layers, and specific surface areas of up to 1654 m 2 g -1 was produced on gram-scale by template growth on porous MgO layers. Its unique porous structure gave excellent electrochemical capacitance (up to 255 F g -1), cycle stability and rate performance. © 2011 The Royal Society of Chemistry.


Xu H.,Wayne State University | Du J.,Harbin Engineering University | Li W.L.,Wayne State University
Journal of Sound and Vibration | Year: 2010

This paper presents an analytical method for the vibration analysis of plates reinforced by any number of beams of arbitrary lengths and placement angles. Both the plate and stiffening beams are generally modeled as three-dimensional (3-D) structures having six displacement components at a point, and the coupling at an interface is genetically described by a set of distributed elastic springs. Each of the displacement functions is here invariably expressed as a modified Fourier series, which consists of a standard Fourier cosine series plus several supplementary series/functions used to ensure and improve uniform convergence of the series representation. Unlike most existing techniques, the current method offers a unified solution to the vibration problems for a wide spectrum of stiffened plates, regardless of their boundary conditions, coupling conditions, and reinforcement configurations. Several numerical examples are presented to validate the methodology and demonstrate the effect on modal parameters for a stiffened plate with various boundary conditions, coupling conditions, and reinforcement configurations. © 2010 Elsevier Ltd. All rights reserved.


Yan J.,Harbin Engineering University | Fan Z.,Harbin Engineering University | Wei T.,Harbin Engineering University | Qian W.,Tsinghua University | And 2 more authors.
Carbon | Year: 2010

We present a quick and easy method to synthesize graphene-MnO2 composites through the self-limiting deposition of nanoscale MnO2 on the surface of graphene under microwave irradiation. These nanostructured graphene-MnO2 hybrid materials are used for investigation of electrochemical behaviors. Graphene-MnO2 composite (78 wt.% MnO 2) displays the specific capacitance as high as 310 F g-1 at 2 mV s-1 (even 228 F g-1 at 500 mV s-1), which is almost three times higher than that of pure graphene (104 F g -1) and birnessite-type MnO2 (103 F g-1). Interestingly, the capacitance retention ratio is highly kept over a wide range of scan rates (88% at 100 mV s-1 and 74% at 500 mV s-1). The improved high-rate electrochemical performance may be attributed to the increased electrode conductivity in the presence of graphene network, the increased effective interfacial area between MnO2 and the electrolyte, as well as the contact area between MnO2 and graphene. © 2010 Elsevier Ltd. All rights reserved.


Li J.,Harbin Engineering University | Yang L.,Harbin Engineering University | Yang L.,York University
Mathematical Problems in Engineering | Year: 2014

This paper proposes an adaptive proportion-integral (PI)-based sliding mode control design (APISMC) used for nanopositioning of piezoelectric actuators (PEAs). Nonlinearities, mainly hysteresis, can drastically degrade the system performance. As well as the model imperfection, hysteresis can be treated as uncertainties of the system. These uncertainties can be addressed by sliding mode control (SMC) since SMC is promising for positioning and tracking control. To further improve the response speed, suppress chattering, and reduce the steady-state error, the adaptive PI-based SMC is employed to replace the discontinuous control. Actually, the adaptive PI-based SMC offers a fast convergence of the sliding surface. Further, another advantage of the proposed controller lies in that its implementation only requires the online tuning PI parameters without acquiring the knowledge of bounds on system uncertainties. A linear second-order system is utilized as the estimated model to compensate for the process nonlinearity and estimate the control gain. The robust stability of the APISMC is proved through a Lyapunov stability analysis. Simulation results demonstrate that the modified SMC is superior to the original one for both positioning and tracking applications. Compared with the original, the proposed controller provides better performance - less chattering, faster response, and higher precision. © 2014 Jin Li and Liu Yang.


Wang R.,CAS Beijing National Laboratory for Molecular | Li X.,CAS Beijing National Laboratory for Molecular | Bai J.,Harbin Engineering University | Zhang J.,CAS Beijing National Laboratory for Molecular | And 2 more authors.
Macromolecules | Year: 2014

Six novel chiral bulky styrenic monomers, (+)-2-[4′-((S)-2″- methylbutyloxy)phenyl]-5-phenylstyrene (A-1), (+)-2-[4′-((S)-2″- methylbutyloxy)phenyl]-5-(4′-fluorophenyl)styrene (A-2), (+)-2-[4′-((S)-2″-methylbutyloxy)phenyl]-5-(4′-tert- butylphenyl)styrene (A-3), (+)-2-phenyl-5-[4′-((S)-2″- methylbutyloxy)phenyl]styrene (B-1), (+)-2-(4′-fluorophenyl)-5-[4′- ((S)-2″-methylbutyloxy)phenyl]styrene (B-2), and (+)-2-(4′-tert- butylphenyl)-5-[4′-((S)-2″-methylbutyloxy)phenyl]styrene (B-3), were synthesized and radically polymerized to yield the corresponding polymers, PA-1-PA-3 and PB-1-PB-3. All of them consisted of laterally attached p-terphenyl pendants terminated by an identical (+)-(S)-2-methylbutyloxy end and an achiral end with various size. The first three differed the others by the position of vinyl group relative to chiral motifs. Evidenced by the results of NMR, polarimetry, circular dichroism spectroscopy, computer simulation, thermal properties, and X-ray diffractions, the chiral p-alkoxyphenyl group ortho to the vinyl group induced the helical conformation of polymer backbone with an excess screw sense as in PA-1-PA-3, whereas that meta to the vinyl group failed to dictate the growth of polymer backbone. The achiral end of the side group had a great effect on the optical rotation of polymer. The specific optical rotation of PA-3 that bore tertiary butyl groups was over 3 times larger than PA-1 and PA-2 terminated with hydrogen and fluorine atoms. Accompanied by the existence of helical structure with a predominant screw sense, stable liquid crystalline phases were generated by PA-1-PA-3 at above glass transition temperatures but not by PB-1-PB-3. An unusual glass transition temperature and structure relationship was also revealed. © 2014 American Chemical Society.


Gao Z.,University of Virginia | Gao Z.,Harbin Engineering University | Yang W.,Harbin Engineering University | Wang J.,Harbin Engineering University | And 2 more authors.
Nano Energy | Year: 2015

Two nanostructured electrodes were fabricated and used to construct flexible high performance supercapacitors. Hierarchical NiCo2O4 nanostructures (with airy organdy NiCo2O4 nanosheets on vertical NiCo2O4 nanoarrays) were grown on flexible carbon cloth by a facile template-free method while three dimensional (3D) porous graphene papers (PGP) with scaffold-like microstructure were fabricated by freeze-drying. The hierarchical NiCo2O4/carbon cloth (NiCo2O4/CC) and PGP electrodes achieved the maximum specific capacitance of 1768 (based on the mass of NiCo2O4) and 151Fg-1, respectively. The NiCo2O4/CC (as the positive electrode), PGP (as the negative electrode), and PVA-LiOH gel (as both the solid state electrolyte and separator) were assembled into flexible all-solid-state (NiCo2O4/CC//PGP) asymmetric supercapacitor with an exceptional combination of electrochemical properties in terms of working potential (1.8V), maxmum energy density (60.9Whkg-1), maxmium power density (11.36kWkg-1), and cycling stability (96.8% capacitance retention ratio over 5000 cycles under mechanical bending). © 2015 Elsevier Ltd.


Zhu X.,China University of Petroleum - Beijing | Ning G.,China University of Petroleum - Beijing | Fan Z.,Harbin Engineering University | Gao J.,China University of Petroleum - Beijing | And 3 more authors.
Carbon | Year: 2012

Graphene-carbon nanotube (G-CNT) hybrids were synthesized by a one-step chemical vapor deposition process using a mixed catalyst of MgO and Fe/MgO. MgO layers acted as templates for the growth of graphene, and Fe particles on the MgO layers catalyzed the growth of single or double-walled CNTs. The G-CNT hybrids had porous structures with hierarchical pore distributions due to the composition of graphene with CNT network. Superparamagnetism with a saturation magnetization of 2.7 emu/g was found in the G-CNT hybrids due to the existence of Fe 3C nanoparticles of size ∼3 nm. The graphene to CNT ratio was conveniently changed by varying the MgO to Fe/MgO ratio, as characterized by Raman analysis and specific surface area measurements. Furthermore, a simplified synthesis of G-CNT hybrids was demonstrated by using MgO supported Fe or Ni catalysts with a low metal concentration. © 2012 Elsevier Ltd. All rights reserved.


Jing Y.,Harbin Institute of Technology | Wu G.,Harbin Engineering University | Guo L.,Harbin Institute of Technology | Sun Y.,Harbin Institute of Technology | Shen J.,Harbin Institute of Technology
Computational Materials Science | Year: 2013

Using the non-equilibrium Green's function method together with the density-functional theory, the electronic transport properties of graphyne and its family have been studied. Unlike graphene, the graphyne and its family display semi-conductive characteristic along zigzag direction and metallic characteristic along armchair direction. The transport properties of graphyne and its family are associated with the length of C link in their structures. With the length of C link increasing, the electrical conductivity decreases. In addition, both the zigzag and armchair graphdiyne nanoribbons display semi-conductive characteristic. The armchair graphene-graphdiyne nanoribbon heterojunction displays symmetrical semi-conductive characteristic. However, the zigzag graphene-graphdiyne nanoribbon heterojunction shows asymmetrical metallic characteristic and displays the superior rectification behavior. Comparison with the previous studies, it can be found that the heterojunction constructed with metallic and semi-conductive nanoelements which behave distinct electronic structures can display the rectification behavior, and it can open up opportunities for design of nanodevices. © 2013 Published by Elsevier B.V. All rights reserved.


Qi B.,Harbin Engineering University | Zhao C.,Harbin Engineering University | Youn E.,Texas Tech University | Nansen C.,Texas AgriLife Research Center | Nansen C.,University of Western Australia
Optics Express | Year: 2011

Support vector machine (SVM) is widely used in classification of hyperspectral reflectance data. In traditional SVM, features are generated from all or subsets of spectral bands with each feature contributing equally to the classification. In classification of small hyperspectral reflectance data sets, a common challenge is Hughes phenomenon, which is caused by many redundant features and resulting in subsequent poor classification accuracy. In this study, we examined two approaches to assigning weights to SVM features to increase classification accuracy and reduce adverse effects of Hughes phenomenon: 1) "RSVM" refers to support vector machine with relief feature weighting algorithm, and 2) "FRSVM" refers to support vector machine with fuzzy relief feature weighting algorithm. We used standardized weights to extract a subset of features with high classification contribution. Analyses were conducted on a reflectance data set of individual corn kernels from three inbred lines and a public data set with three selected land-cover classes. Both weighting methods and reduction of features increased classification accuracy of traditional SVM and therefore reduced adverse effects of Hughes phenomenon. © 2011 Optical Society of America.


Chen M.,Harbin Engineering University | Wang Z.-B.,Harbin Institute of Technology | Zhou K.,Harbin Engineering University | Chu Y.-Y.,Harbin Institute of Technology
Fuel Cells | Year: 2010

Pd catalyst supported on Vulcan XC-72 carbon black was prepared by a modified polyol process. Its performance was compared with that of Pd/C catalyst prepared by impregnation reduction method by using NaBH4 as a reducing agent for formic acid electrooxidation. Their physical characterisations were tested by means of energy dispersive analysis of X-ray, X-ray diffraction and transmission electron micrographs. Their activities were presented by cyclic voltammetry and chronoamperometry. The results show that the particle sizes of Pd/C catalysts prepared by modified polyol process and impregnation reduction method are 3.9 and 7.9 nm, respectively. The size dispersion of the former is narrower and more homogeneous than that of the latter. However, both of Pd/C catalysts display the characteristic diffraction peaks of a Pd face-centred cubic (f.c.c.) crystal structure. The results of electrochemical measurements present that the Pd/C catalyst prepared by modified polyol process has the higher electrocatalytic activity and stability for formic acid electrooxidation in comparison to the Pd/C one by impregnation reduction method due to the particle size effect, and its peak current density of CV and the current of chronoamperometric curve at 1,000 s reach 33.2 and 11.2 mA cm-2, respectively. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gong W.-J.,Harbin Engineering University | Liang H.,Harbin Institute of Technology | Li W.-Z.,Harbin Engineering University | Wang Z.-Z.,Harbin Engineering University
Energy | Year: 2011

Selection and evaluation of biofilm carrier represent the two significant ways for improving the anaerobic digesters. This study investigated the performances of the AD (anaerobic digestion) reactors using three types of fibrous biofilm carriers, including the ACF (activated carbon fiber), the PVAF (polyvinyl alcohol fiber) and the GF (glass fiber). The biogas and methane production, pH, COD (chemical oxygen demand), TS (total solids), VS (volatile solids), residual coenzyme F420 as well as the residual amount of methanogen were measured periodically during the experimental run. Also, the SEM (scanning electron microscopy) was used to identify the microbial consortium and their attachments onto the surface of ACF carrier. The ACF carrier performed better than the other two types of carriers in achieving higher amount of biogas and methane production and pollutants' removal. The experimental results also demonstrated that the ACF carrier could make the reactor keep higher biogas and methane productions than the control blank reactor during the long run. © 2011 Elsevier Ltd.


Du C.,Harbin Institute of Technology | Gao C.,Harbin Institute of Technology | Yin G.,Harbin Institute of Technology | Chen M.,Harbin Engineering University | Wang L.,Harbin Engineering University
Energy and Environmental Science | Year: 2011

In this paper, we demonstrate that a novel silicon electrode with a large amount of nanopores can be fabricated by an in-situ thermal generating approach using triethanolamine as a sacrificing template. The fabrication process is simple, green, low cost, and easy to be scaled up. This electrode achieves high reversible capacities (2500 mAh g-1) with excellent cycling stability (∼90% capacity retention after 100 charge-discharge cycles), showing great potential as a high-performance anode for lithium-ion batteries. It is revealed that the high void volume with pore size of <200 nm can both enlarge the interface between active silicon particles and the electrolyte, and accommodate the severe volume change of silicon, thus leading to remarkably improved reversible capacity and cycling stability. The design concept and the fabrication approach used in the nanoporous silicon electrode may also be extended to other electrodes for electrochemical applications. © 2011 The Royal Society of Chemistry.


Tan Q.,Harbin Institute of Technology | Du C.,Harbin Institute of Technology | Yin G.,Harbin Institute of Technology | Zuo P.,Harbin Institute of Technology | And 2 more authors.
Journal of Catalysis | Year: 2012

This paper reports the easy synthesis of Au@Pd core-shell nanoparticles (NPs) with uniform shell thickness and demonstrates their viability as a nonplatinum catalyst for the electrooxidation of methanol in alkaline anion-exchange membrane fuel cells. The synthesis involves the first preparation of Au core NPs, followed by a three-phase-transfer procedure to coat Pd shells, through which homogeneous Pd shell growth on Au cores can be achieved. The as-prepared Au@Pd NPs have an activity more than 40 times higher than that of the Pd catalyst for the methanol oxidation. Moreover, these Au@Pd NPs possess excellent stability (over seven times more stable than Pd catalysts). The remarkable performance enhancement is mainly attributed to the finely tailored electronic structure of the Pd shell achieved by the underlying Au core. The easily synthesized Au@Pd core-shell NPs represent a promising class of nonplatinum anode catalysts with high activity and durability for alkaline fuel cell applications. © 2012 Elsevier Inc. All rights reserved.


Han H.-Z.,Harbin Engineering University | Han H.-Z.,Harbin Institute of Technology | Li B.-X.,Harbin Institute of Technology | Wu H.,Harbin Institute of Technology | Shao W.,Harbin Institute of Technology
International Journal of Thermal Sciences | Year: 2015

Integrated a fully developing three-dimensional heat transfer and flow model, a multi-objective optimization aims to fulfill the geometric design for double-tube heat exchangers with inner corrugated tube is investigated in this work with RSM. Dimensionless corrugation pitch (p/D), dimensionless corrugation height (H/D), dimensionless corrugation radius (r/D) and Reynolds number (Re) are considered as four design parameters. Considering the process parameters, the characteristic numbers involving heat transfer characteristic, resistance characteristic and overall heat transfer performance calculated by CFD, and are served as objective functions to the RSM (Nuc, fc, Nuc/Nuc, fs/fc and σ in this paper). The results of optimal designs are a set of multiple optimum solutions, called 'Pareto optimal solutions'. It reveals the identical tendency of Nuc/Nus and fc/fs reflecting the conflict between them that means augmenting the heat transfer performance with various design parameters in the optimal situation inevitably sacrificed the increase of flow resistance. According to the Pareto optimal curves, the optimum designing parameters of double pipe heat exchanger with inner corrugated tube under the constrains of Nuc/Nus ≥ 1.2 are found to be P/D = 0.82, H/D = 0.22, r/D = 0.23, Re = 26,263, corresponding to the maximum value of σ = 1.12. © 2014 Elsevier Masson SAS. All rights reserved.


Du C.,Harbin Institute of Technology | Chen M.,Harbin Engineering University | Wang W.,Harbin Engineering University | Yin G.,Harbin Institute of Technology
ACS Applied Materials and Interfaces | Year: 2011

Highly active and durable catalysts for formic acid oxidation are crucial to the development of direct formic acid fuel cell. In this letter, we report the synthesis, characterization, and electrochemical testing of nanoporous Pd57Ni43 alloy nanowires for use as the electrocatalyst towards formic acid oxidation (FAO). These nanowires are prepared by chemically dealloying of Ni from Ni-rich PdNi alloy nanowires, and have high surface area. X-ray diffraction data show that the Pd57Ni43 nanowires have the face-centered cubic crystalline structure of pure Pd, whereas X-ray photoelectron spectroscopy confirm the modification of electronic structure of Pd by electron transfer from Ni to Pd. Electrocatalytic activity of the nanowires towards FAO exceeds that of the state-of-the-art Pd/C. More importantly, the nanowires are highly resistant to deactivation. It is proposed that the high active surface area and modulated surface properties by Ni are responsible for the improvement of activity and durability. Dealloyed nanoporous Pd57Ni43 alloy nanowires are thus proposed as a promising catalyst towards FAO. © 2010 American Chemical Society.


Tan Y.,Harbin Institute of Technology | Ouyang J.,Harbin Institute of Technology | Lv J.,Harbin Institute of Technology | Lv J.,Harbin Engineering University | Li Y.,Harbin Institute of Technology
Construction and Building Materials | Year: 2013

Cement asphalt mortar (CA mortar) is a key material of non-ballasted track structure. In order to solve the problem that cement hardens slowly in CA mortar, the retarding effect of emulsifier on cement hydration was studied by measurement of cement setting time, hydration heat and X-ray diffraction analysis. Results show that emulsifier has significant retarding effect on cement hydration, which is relevant to the types of emulsifier and its dosages. The retarding effect increases with the increment of the mass ratio of emulsifier to cement. Significant differences in the setting time, cement hydration rate, hydration heat and the content of Ca(OH)2 are detected utilizing different types of emulsifier. Emulsifier with excessive retarding effect on cement not only abort cement hydration in early age, but also cause a loss in the later hydration heat and content of cement hydrates. Therefore, suitable emulsifier with little retarding effect on cement hydration and its appropriate dosage are recommended when producing asphalt emulsion for CA mortar. © 2013 Elsevier Ltd. All rights reserved.


Zhang K.,Harbin Engineering University | Ren N.-Q.,Harbin Institute of Technology | Wang A.-J.,Harbin Institute of Technology
International Journal of Hydrogen Energy | Year: 2014

Five individual pretreatment methods (heat, ultrasonic, ultraviolet, acid, and base) were performed on two typical seed sludges (river sediments and anaerobic granular sludge) to evaluate their effectiveness on enriching efficient hydrogen (H2)-producing bacteria and enhancing H 2 production using corn stover hydrolyzate. Results indicated that pretreatment processes caused more remarkable improvements for river sediments than anaerobic granular sludge. Among the five protocols, heat pretreatment reached high H2 yield for both river sediments (4.17 mmol H 2/g utilized sugar) and anaerobic granular sludge (2.84 mmol H 2/g utilized sugar). Ultraviolet and ultrasonic pretreatments were conditionally effective for river sediments and anaerobic granular sludge, respectively. In most cases, pretreatment processes altered soluble metabolites distribution towards more acetate and less ethanol production. Microbial community analysis indicated that heat and ultrasonic pretreatments can respectively lead to significant and indistinctive change on original microbial community. Besides frequently detected Escherichia spp., Serratia spp., and Klebsiella spp., some species of Clostridium spp. and Bacillus spp. might be efficient H2 producer responsible for better H2-producing performances. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Liu S.,Harbin Engineering University | Zhang Y.,Harbin Institute of Technology
Applied Optics | Year: 2012

We describe the effects of incoherent pump on an atomic filter based on laser-induced optical anisotropy in a three-level ladder system interacting with a strong pump polarized circularly and a weak probe polarized linearly. According to the analysis of the numerical simulation results with some comparison, at the same time of eliminating noise, the filter can enhance the probe's transmission or even the probe gain can be achieved without population inversion. Moreover, the incoherent pumping rate and the cell temperature performance are evaluated and measures are taken to improve the filter's transmission and tunability by selecting proper parameters. © 2012 Optical Society of America.


Guo X.,Harbin Engineering University | Liu L.,Harbin Institute of Technology | Liu Y.,Harbin Institute of Technology | Zhou B.,China University of Petroleum - East China | Leng J.,Harbin Institute of Technology
Smart Materials and Structures | Year: 2014

Recently, increasing applications of shape memory polymers have pushed forward the development of appropriate constitutive models for smart materials such as the shape memory polymer. During the heating process, the phase transition, which is a continuous time-dependent process, happens in the shape memory polymer, and various individual phases will form at different configuration temperatures. In addition, these phases can generally be divided into two parts: the frozen and active phase (Liu Y et al 2006 Int. J. Plast. 22 279-313). During the heating or cooling process, the strain will be stored or released with the occurring phase transition between these two parts. Therefore, a shape memory effect emerges. In this paper, a new type of model was developed to characterize the variation of the volume fraction in a shape memory polymer during the phase transition. In addition to the temperature variation, the applied stress was also taken as a significant influence factor on the phase transition. Based on the experimental results, an exponential equation was proposed to describe the relationship between the stress and phase transition temperature. For the sake of describing the mechanical behaviors of the shape memory polymer, a three-dimensional constitutive model was established. Also, the storage strain, which was the key factor of the shape memory effect, was also discussed in detail. Similar to previous works, we first explored the effect of applied stress on storage strain. Through comparisons with the DMA and the creep experimental results, the rationality and accuracy of the new phase transition and constitutive model were finally verified. © 2014 IOP Publishing Ltd.


Wang X.J.,Harbin Institute of Technology | Wang N.Z.,Harbin Institute of Technology | Wang L.Y.,Harbin Turbine Company Ltd | Hu X.S.,Harbin Institute of Technology | And 3 more authors.
Materials and Design | Year: 2014

The novel stir casting assisted by ultrasonic treatment processing was studied. Unlike traditional stir casting, short semi-solid stir time was needed for addition and pre-dispersion of the particles in the novel processing. For ultrasonic treatment, there existed an optimal time. Both too short and too long time for the treatment resulted in nonhomogeneous particle distribution. Furthermore, the liquid stirring after ultrasonic treatment was proved to be necessary to further improve particle distribution. The mechanical properties of the composites fabricated by different parameters indicated that ultrasonic treatment evidently improved the mechanical properties compared with traditional stir casting. 5-20% SiCp/AZ91 composites were fabricated by the novel processing. The particle distribution was uniform in these composites. The grains were refined by addition of SiC particles. Grain sizes of composites decreased with the increases of particle contents. The ultimate tensile strength, yield strength and elastic modulus were enhanced as the particle contents increased. © 2014 Elsevier Ltd.


Wang M.,Harbin Institute of Technology | Zhang Y.,Harbin Engineering University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2016

To understand the spreading of invasive and native species, in this paper we consider the diffusive competition models with a free boundary in the heterogeneous time-periodic environments, in which the variable intrinsic growth rates of these two species change signs and may be very negative in some large regions. We study the spreading–vanishing dichotomy, long-time dynamical behavior of solution, sharp criteria for spreading and vanishing, and estimates of the asymptotic spreading speed of the free boundary. Moreover, we establish the existence of positive solutions to a T-periodic boundary value problem of the diffusive competition system with sign-changing growth rates in the half line. © 2016, Springer International Publishing.


Wang X.,Harbin Engineering University | Zhang J.,Harbin Engineering University | Wang Z.,Harbin Engineering University | Zhou S.,Harbin Engineering University | Sun X.,Harbin Institute of Technology
Materials and Design | Year: 2011

A micromechanical study has been performed to investigate the mechanical properties of unidirectional fiber reinforced composite materials under transverse tensile loading. In particular, the effects of different properties of interphase within the representative volume element (RVE) on both the transverse effective properties and damage behavior of the composites have been studied. In order to evaluate the effects of interphase properties on the mechanical behaviors of unidirectional fiber reinforced composites considering random distribution of fibers, the interphase is represented by pre-inserted cohesive element layer between matrix and fiber with tension and shear softening constitutive laws. Results indicate a strong dependence of the RVE transverse effective properties on the interphase properties. Furthermore, both the damage initiation and its evolution are also clearly influenced by the interphase properties. © 2011 Elsevier Ltd.


Chen M.,Harbin Engineering University | Du C.,Harbin Institute of Technology | Zhang J.,Harbin Engineering University | Wang P.,Harbin Institute of Technology | Zhu T.,Harbin Institute of Technology
Journal of Power Sources | Year: 2011

The poisoning of nitrogen oxides (NOx) on the oxygen reduction reaction (ORR) at the Pt/C catalyst has been studied for proton exchange membrane fuel cells by a three-electrode method in liquid electrolyte solution. The cyclic voltammetry (CV) results reveal that the absorption of NOx on metallic Pt is more significant than on Pt oxides, and this absorption is probably a chemical rather than an electrochemical process. Linear sweeping voltammetry (LSV) curves for the ORR show that it is the absorption of NO x on the Pt surface that results in significant performance degradation of Pt/C catalysts. This degradation is mainly due to the reduction of electrochemically active surface area, since the ORR mechanism remains almost the same after the NOx poisoning as revealed by similar Tafel slopes. Because lower potentials facilitate the reduction of NOx to water soluble NH4+, reducing the working potential can mitigate the poisoning of NOx. However, to completely recover the performance loss due to NOx poisoning through the potential sweeping, it is found that the oxidation removal is more efficient than the reduction removal. © 2010 Elsevier B.V.


Ma Y.,Harbin Institute of Technology | Li N.,Harbin Institute of Technology | Li N.,Harbin Engineering University | Li D.,Harbin Institute of Technology | And 2 more authors.
Journal of Power Sources | Year: 2011

In this research, a new Mg-air battery based on Mg-14Li-1Al-0.1Ce was prepared and the battery performance was investigated by constant current discharge test. The corrosion behavior of Mg, AZ31 and Mg-Li-Al-Ce were studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The characteristics of Mg-Li-Al-Ce after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that Mg-Li-Al-Ce is more active than Mg and AZ31. The self-corrosion rate is found to be in the order: Mg-Li-Al-Ce < Mg < AZ31. It has been observed that the Mg-air battery based on Mg-Li-Al-Ce offers higher operating voltage, anodic efficiency and capacity than those with Mg and AZ31. SEM and EIS results show that the discharge product of Mg-Li-Al-Ce is loosely adhered to the alloy surface, and thus Mg-Li-Al-Ce could keep high discharge activity during discharge. © 2010 Elsevier B.V.


Fang G.,Harbin Institute of Technology | Liang J.,Harbin Institute of Technology | Lu Q.,Harbin Institute of Technology | Wang B.,Harbin Engineering University | Wang Y.,Harbin Institute of Technology
Composite Structures | Year: 2011

The compressive mechanical properties of three dimensional (3D) braided composites are of key concern for design in actual engineering application. A representative volume cell (RVC) is chosen to study the uniaxial compressive mechanical properties of the braided composites with different braid angles by combing damage theory and finite element method. The fiber misalignment and longitudinal shear nonlinearity of braid yarn are considered in the computation model. And their influences on the compressive behavior of the braided composites are also evaluated. The damage development of constituents within the braided composites are obtained and analyzed. The main damage and failure modes and their interaction of braid yarn are provided as well. The numerical results are found that the compressive mechanical behavior of the braided composites with lower braid angle is sensitive to the fiber initial imperfection of braid yarn. The strength of the braided composites with different braid angle is controlled by the different microscopic failure modes. © 2010 Elsevier Ltd.


Ke T.,CAS Shanghai Advanced Research Institute | Zheng Q.,Harbin Engineering University
Nuclear Engineering and Design | Year: 2012

A design study of multistage axial helium compressor of a 300 MWe high temperature gas-cooled reactor is presented in this paper. Helium compressor is characterized by shorter blades, narrow flow channels, numerous stages and longer slim rotor, which result in losses due to blade surface and end wall boundary layers growths, secondary flows and clearance leakage flows, any occurrence of flow separation and stage mismatch. Therefore, the purpose of this paper is to improve and optimize the aerodynamic design of helium compressor. The property of helium is different from that of air, so how to choose the design parameters of a helium compressor is discussed first. And then how to shorten the axial length of the helium compressor or how to decrease the number of stages for a certain pressure ratio by increasing the stage loading are investigated. The new highly loaded helium compressor of larger flow coefficient and high reaction is designed and optimized. Three-dimensional flow patterns in a helium stage are simulated with CFD software (NUMECA). Adjusting the position of blade maximum camber deflection position; redistributing radial compression work; 3D blading techniques, such as distribution spanwise relative airfoil thickness, custom tailoring airfoils and bowed stator vane to mitigate end wall boundary layers and corner separation have improved the aerodynamic performance of the first stage of helium compressor. © 2012 Elsevier B.V.


Baoquan K.,Harbin Institute of Technology | Chunyan L.,Harbin Engineering University | Shukang C.,Harbin Institute of Technology
IEEE Transactions on Plasma Science | Year: 2011

The permanent-magnet (PM) synchronous motor (PMSM) takes advantages of small capacity, high efficiency, and high power density and have become commonplace in electric-vehicle driving systems. However, the excitation of PMSM cannot be adjusted, which restrains the PMSM from widening the speed range above its base speed. A PMSM with a variable magnetic reluctance field adjustment is presented in this paper. A new structure of the rotor is introduced, and flux-weakening (FW) principle is formulated. Analysis is discussed, including the force on the main PM, the movement process of the PM in the PM slot, the characteristics of the movement of the PM, and the FW performance of the new PMSM used for electric vehicles. The emulation analysis coincides with the test result, which verifies the availability and feasibility of the FW method for this kind of PMSM used for electric vehicles. © 2010 IEEE.


Ren Y.-M.,Harbin Engineering University | Yang J.,Harbin Engineering University | Ma W.-Q.,Qingdao Municipal Engineering Design Research Institute | Ma J.,Harbin Institute of Technology | And 2 more authors.
Water Research | Year: 2014

A molecular imprinted particle for Bisphenol A (BPA-MIP) was successfully used for selective recognition of BPA in the water. The contaminants such as 3, 3', 5, 5'-Tetrabromobisphenol A (TBBPA), phenol and phenol red (PSP) were selected as the latent interferon to investigate the selectivity. The binding efficiencies of BPA-MIP for different phenols were explored at various initial concentrations in the single and mixed water. Various selective parameters such as Kd, K and K' of BPA-MIP for BPA were calculated. The influences of humic acid (HA) and common ions on the BPA binding were investigated. A physical model was proposed to illustrate the selective binding performance. The results showed that BPA-MIP possessed strong selectivity for BPA in competitive water, while the other similar phenols had the influence for BPA binding at the order of TBBPA > phenol > PSP. The HA and common ions indicated little effect on the BPA binding process onto BPA-MIP. It was found that the molecular geometry and the hydrogen bonding interactions between the hydroxyl and carboxyl played an important role in recognizing the target molecular in the binding process. © 2013 Elsevier Ltd.


Yang X.T.,Harbin Engineering University | Yao B.Y.,Harbin Institute of Technology
Optik | Year: 2014

We reported the Ho:GdVO4 laser pumped by Tm-doped laser with a fiber Bragg grating. 2.03 W continuous-wave Ho:GdVO4 laser output power is obtained under 10.5 W incident pump power, with the optical-to-optical conversion efficiency and slope efficiency of 19.3% and 32.3%, respectively, at 7 °C. We can see that, the lower the temperature is, the better the laser output character is. The beam quality factor is M2 ∼ 1.29 measured by the traveling knife-edge method. © 2014 Elsevier GmbH. All rights reserved.


Lv J.,Harbin Engineering University | Mao J.,Harbin Engineering University | Ba H.,Harbin Institute of Technology
Construction and Building Materials | Year: 2015

This work investigated the inhibition of ions transporting into and out of the mortar by Pseudoalteromonas (strain B18) and Paracoccus marcusii (strain B23). Mortar samples were immersed for 154 days in sterilized seawater, 2216E liquid medium, and 2216E liquid medium containing one of the above strains. Two strains positively decelerated chloride (Cl-) ions and magnesium (Mg2+) ions in the solutions permeating into the mortar and OH- ions leaching out from the mortar. And strain B23 is stronger than strain B18 in reducing the permeation of Cl- ions and Mg2+ ions into and the leakage of OH- ions out of the mortar. Micro structural observation revealed that the biofilm with rod-shaped bacteria covered the mortar surface. Some fibrous and colloidal substances were observed between cells. Thus, biofilm formation can lower the ion permeability of mortar samples. And it can enhance the durability of reinforced concrete (RC) structures located in tidal zones. © 2014 Elsevier Ltd. All rights reserved.


Wang L.,Harbin Institute of Technology | Sun X.,Harbin Institute of Technology | Xing J.,Harbin Engineering University
Optics Communications | Year: 2012

Retrieval of spheroidal particle size distribution using an approximate method in spectral extinction technique is proposed. The combined approximate method, which is the combination of Mie method and generalized eikonal approximation (GEA) method, is used as an alternative to the rigorous solutions to calculate the averaging extinction efficiency of spheroid. Based on the averaging extinction efficiency, the accuracy and limitations of the retrieval are then investigated. Moreover, the validity range and effect of the refractive index are also examined. The Johnson's S B function in this paper is used as a versatile function to fit the commonly used particle size distribution functions in the dependent model. Simulations and experimental results show that the combined approximate method can be successfully applied to retrieval of spheroidal particle size distribution. In certain constraint conditions, the retrieval results demonstrate the high reliability and stability of the method. By using the combined approximate method, the complexity and computation time of the retrieval are significantly reduced, which is more suitable for quick and easy measurement. The method can also be used as a replacement when the rigorous solutions suffer computationally intractable difficulties. © 2011 Elsevier B.V. All rights reserved.


Yao J.,Harbin Engineering University | Di D.,Harbin Engineering University | Han J.,Harbin Institute of Technology
JVC/Journal of Vibration and Control | Year: 2012

The acceleration output of an electro-hydraulic servo system corresponding to a sinusoidal input contains higher harmonics besides the fundamental input, because of complex nonlinearities occurring in the system. This causes harmonic distortion of the acceleration signal. The method for harmonic elimination based on adaptive notch filter is proposed here. The task is accomplished by generating a reference signal with a frequency that should be eliminated from the output. The reference input is filtered in such a way that it closely matches the harmonic. The filtered reference signal is added to the fundamental signal such that the output harmonic is cancelled leaving the desired signal alone. The weights of the adaptive filter are adjusted by the error between the input and the feedback acceleration to eliminate acceleration harmonic, creating an adaptive notch filter. The above concept is used as a basis for the development of an acceleration harmonic cancellation algorithm. Results of simulation and experiment on an electro-hydraulic servo shaking table demonstrate the efficiency and validity of the proposed control scheme. © The Author(s) 2011.


Liu C.-Y.,Harbin Engineering University | Jiang T.,Harbin Engineering University | Li Y.-S.,Harbin Engineering University | Li Y.-S.,Harbin Institute of Technology
Journal of Electromagnetic Waves and Applications | Year: 2011

This paper presents a novel approach for designing compact ultra-wideband (UWB) bandpass filter with a good notched band characteristic. A notch band characteristic is obtained by using the radial-uniform impedance resonators (UIR)/stepped impedance resonators (SIR) loaded stub resonator. The main advantage of the proposed filter is that the frequency of the notched band can be tuned easily in a wide frequency range. Current density and equivalent model is also given depending on the odd/even excitation resonance condition. The characteristics of the filter are analyzed. To verify the proposed methods, two filters are designed and fabricated. Measured results show that the proposed UWB properties from 3 to 10.8 GHz and the notch band can be changed optionally from 4 GHz to 10 GHz. These filters can be integrated in UWB radio systems and efficiently enhance the interference immunity from undesired signals such as wireless local area network (WLAN) and WiMAX. © 2011 VSP.


Ren Y.,Harbin Engineering University | Lin L.,Harbin Engineering University | Ma J.,Harbin Institute of Technology | Yang J.,Harbin Engineering University | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2015

Magnetic ferrospinel MFe2O4 (M=Co, Cu, Mn, and Zn) prepared in a sol-gel process was introduced as catalyst to generate powerful radicals from peroxymonosulfate (PMS) for refractory di-n-butyl phthalate (DBP) degradation in the water. Various catalysts were described and characterized, and the catalytic activities in PMS oxidation system were investigated. Most important of all, the mechanism of different catalysts in the catalytic PMS solution was illustrated. The results showed that the incorporation of CoFe2O4 had the highest catalytic performance in PMS oxidation for DBP degradation. All catalysts presented favorable recycling and stability in the repeated batch experiment. The catalytic process showed a dependence on initial pH, and an uncharged surface of the catalyst was more profitable for sulfate radical generation. H2-TPR and CVs analysis indicated that the sequence of the catalyst's reducibility in PMS solution was CoFe2O4>CuFe2O4>MnFe2O4>ZnFe2O4, which had a close connection with the activity of metal ion in A site of the catalysts. The surface hydroxyl sites played an important role in the catalytic process, and its quantity determined the degradation of DBP. Moreover, the reactive species in PMS/MFe2O4 system were identified as sulfate radical and hydroxyl radical. The promotion of these radical's reaction was due to the fact that a balance action in the process of M2+/M3+, O2-/O2, occurred, and at the same time, PMS was catalyzed. © 2014 Elsevier B.V..


Ketui D.,Harbin Engineering University | Chi F.,Harbin Engineering University | Shan G.,Harbin Institute of Technology
Measurement: Journal of the International Measurement Confederation | Year: 2016

Radiation thermometers are the instruments most opted for when measuring surface temperatures of high speed rotating parts non-intrusively in many industrial applications. However, reflection of ambient radiation from the measured target goes against the operating principles of most of these thermometers thus introducing errors to the temperature measurements. Reflection errors introduced into single wavelength and ratio pyrometer temperature measurements of a rotating cooled gas turbine blade were investigated in this work through simulation. Errors for the two pyrometers based on varied target surface emissivity, view factor and ambient temperature were calculated. At high ambient temperatures, high view factors and low surface emissivity, errors exceeding 70% and 30% were realized for single wavelength and ratio pyrometers respectively. Thus temperature measured on reflective targets surrounded by surfaces at much higher temperature should be corrected for reflection errors if its reliability is to be guaranteed. © 2016 Elsevier Ltd. All rights reserved.


Ru X.,Harbin Engineering University | Ru X.,Nuclear Power Institute of China | Staehle R.W.,Staehle Consulting
Corrosion | Year: 2013

This review assesses past experiences from superheated fossil plants, supercritical fossil plants, superheated nuclear plants, and light water reactors from the late 1940s until the present. Data from the development and operation of these plants are directly applicable to supercritical water reactor (SCWR) plants being developed currently. This past work can be applied to the development of current designs in the choice of materials, temperature dependencies, effects of stress, and effects of environments on materials. Some of the past data from light water reactor (LWR) technology can be extrapolated into the present SCWR regimes. The past data are in good agreement among the various previous investigators. These past data are considered with respect to specific components in SCWR: fuel cladding, reactor structurals, reactor vessels, and feedwater heaters. Choosing materials for the SCWR applications must recognize that the materials at nominal outlet temperatures are in a dynamic thermal range, i.e., in the nuclear superheat and fossil superheat range, the atomic structures of materials change significantly and change properties such as ductility. It is also possible that compositions and structures of grain boundaries can change, for example, the susceptibility to SCC. The surface temperatures on fuel cladding will be significantly higher than the outlet temperature, and both temperatures will exceed, substantially, the outlet temperatures of present water-cooled plants. Past isothermal data directed toward core structures may not be relevant to the same alloy as fuel cladding. The outlet temperature is useful for considering core structural materials but not for fuel elements, owing to an inevitably high film drop. SCW environments are expected to produce extensive SCC, which differs from past experience. Finally, past data were reanalyzed and additional useful insights were obtained. © 2013, NACE International.


Zhang F.,Harbin Engineering University | Yu D.,Harbin Institute of Technology | Ding Y.,Harbin Institute of Technology | Li H.,Harbin Institute of Technology
Applied Physics Letters | Year: 2011

A two-dimensional particle in cell model is used to simulate the sheath oscillation in stationary plasma thrusters. The embedded secondary electron emission (SEE) submodel is based on that of Morozov but improved by considering the electron elastic reflection effect. The simulation results show that when the SEE coefficient is smaller than one due to the relative low electron temperature, one-dimensional static sheath can be found; as the electron temperature increase, the SEE coefficient approaches to one and temporal oscillation sheath appears; when the electron temperature increases so high that the SEE coefficient is beyond one, the sheath oscillates not only in time but also in space. © 2011 American Institute of Physics.


Du C.,Harbin Institute of Technology | Chen M.,Harbin Engineering University | Wang W.,Harbin Engineering University | Yin G.,Harbin Institute of Technology | Shi P.,Harbin Institute of Technology
Electrochemistry Communications | Year: 2010

Bimetallic palladium-nickel (PdNi2) alloy catalyst has been prepared for the electrooxidation of formic acid through a simple electrodepositing approach. Scanning Electron Microscopy and X-ray Diffraction revealed that the particle morphology and the crystalline lattice of PdNi 2 alloy were highly different from those of Pd. Although the PdNi2 catalyst had less noble Pd content, the cyclic voltammetry and chronoamperometry results clearly demonstrated that its catalytic activity was significantly higher than that of Pd. The novel enhancement of catalytic activity was mainly ascribed to the weak absorption strength of intermediates on Pd through the interaction between Pd and additive Ni, which facilitated the formic acid oxidation through direct pathway. © 2010 Elsevier B.V. All rights reserved.


Guan Y.-H.,Harbin Institute of Technology | Guan Y.-H.,Harbin University | Ma J.,Harbin Institute of Technology | Ren Y.-M.,Harbin Engineering University | And 4 more authors.
Water Research | Year: 2013

Magnetic porous copper ferrite (CuFe2O4) showed a notable catalytic activity to peroxymonosulfate (PMS). More than 98% of atrazine was degraded within 15min at 1mM PMS and 0.1g/L CuFe2O4. In contrast, CuFe2O4 exhibited no obvious catalytic activity to peroxodisulfate or H2O2. Several factors affecting the catalytic performance of PMS/CuFe2O4 were investigated. Results showed that the catalytic degradation efficiency of atrazine increased with PMS and CuFe2O4 doses, but decreased with the increase of natural organic matters concentration. The catalytic oxidation also showed a dependence on initial pH. The presence of bicarbonate stimulated atrazine degradation by PMS/CuFe2O4 at low concentrations but inhibited the degradation at high concentrations. Furthermore, the reactive species for atrazine degradation in PMS/CuFe2O4 system were identified as hydroxyl radical (HO) and sulfate radical (SO4·-) through competition reactions of atrazine and nitrobenzene, instead of commonly used alcohol scavenging, which was not a reliable method in metal oxide catalyzed oxidation. Surface hydroxyl groups of CuFe2O4 were a critical part in radical generation and the copper on CuFe2O4 surface was an active site to catalyze PMS. The catalytic degradation of atrazine by PMS/CuFe2O4 was also effective under the background of actual waters. © 2013 Elsevier Ltd.


Bao Y.,Harbin Institute of Technology | Li H.,Harbin Institute of Technology | Sun X.,Harbin Engineering University | Yu Y.,Dalian University of Technology | And 2 more authors.
Structural Health Monitoring | Year: 2013

In a wireless sensor network, data loss often occurs during the data transmission between the wireless sensor nodes and the base station. In the wireless sensor network applications for civil structural health monitoring, the errors caused by data loss inevitably affect the data analysis of the structure and subsequent decision making. This article explores a novel application of compressive sampling to recover the lost data in a wireless sensor network used in structural health monitoring. The main idea in this approach is to first perform a linear projection of the transmitted data x onto y by a random matrix and subsequently to transmit the data y to the base station. The original data x are then reconstructed on the base station from the data y using the compressive sampling method. The acceleration time series collected by the field test on the Jinzhou West Bridge and the Structural Health Monitoring System on the National Aquatics Center in Beijing are employed to validate the accuracy of the proposed data loss recovery approach. The results indicate that good recovery accuracy can be obtained if the original data have a sparse characteristic in some orthonormal basis, whereas the recovery accuracy is degraded when the original data are not sparse in the orthonormal basis. © The Author(s) 2012.


Lu F.,Harbin Institute of Technology | Lu F.,Harbin Engineering University | Yu J.,Harbin Institute of Technology
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

For phasor measurement unit (PMU) can't be installed in all buses of a power system, how to analyze power system transient stability with little measurements is an urgent problem to be solved. This paper proposes a method of applying the equal area criterion (EAC) to multi-machine system transient stability assessment directly: the machines with the most leading angle and the most lagging angle are selected, and by fitting their relative power angle curve, EAC is used to identify the transient stability type and to fast calculate the stability index. The advantages of this method is that it avoids machine group division, equivalence, and needs less information and little computation cost. Moreover, it can obtain the same accuracy as time domain simulation method. The validity of the proposed method is proven by an example system. ©2010 State Grid Electric Power Research Institute Press.


Zhang C.,Harbin Institute of Technology | Li J.,Harbin Engineering University | Hu Z.,Harbin Institute of Technology | Zhu F.,Harbin Institute of Technology | Huang Y.,Harbin Institute of Technology
Materials and Design | Year: 2012

Interconnected pore cell in appropriately chosen porous media can help to enhance their sound absorption performance. Acoustic absorbing foam materials were produced from polyurethane (PU) with addition of water as a blowing agent and OR-501 as open pore cell agent. The pore sizes of the foams were varied from 0.35 to 1.05. mm in diameter and the pore cells were interconnected with open porosity in the range from 16.0% to 88.6%. The compressive strength of the foams decreased with increase of interconnected cell ratios. There was a decrease of the strength lower than 92.6% compared to the closed cell sample when interconnected cell ratio was 88.6%. The acoustical efficiencies of PU foams were studied, and the results showed that the porous cell size and interconnected porosity of PU foams had significant influence on the acoustical efficiencies. Significant enhancements of the absorption properties could be obtained over a low frequency band by increasing the interconnected porous cell. The absorption coefficient of the interconnected cell foam was 0.66 at low frequency of 250-600. Hz with an increase of 100% compared to the closed-cell ones. The internal transmission path and loss mechanism of noise in the porous polyurethane materials were also analyzed in the present work. © 2012 Elsevier Ltd.


Wu L.,Harbin Institute of Technology | Wu L.,Harbin Engineering University | Feng Z.,University of Hong Kong | Lam J.,University of Hong Kong
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

This paper is concerned with the problems of exponential stability analysis and synchronization of discrete-time switched delayed neural networks. Using the average dwell time approach together with the piecewise Lyapunov function technique, sufficient conditions are proposed to guarantee the exponential stability for the switched neural networks with time-delays. Benefitting from the delay partitioning method and the free-weighting matrix technique, the conservatism of the obtained results is reduced. In addition, the decay estimates are explicitly given and the synchronization problem is solved. The results reported in this paper not only depend upon the delay, but also depend upon the partitioning, which aims at reducing the conservatism. Numerical examples are presented to demonstrate the usefulness of the derived theoretical results. © 2012 IEEE.


Zhao J.Q.,Harbin Institute of Technology | Zhao J.Q.,Harbin Engineering University | Wang Y.Z.,Harbin Institute of Technology | Yao B.Q.,Harbin Institute of Technology | Ju Y.L.,Harbin Institute of Technology
Laser Physics Letters | Year: 2010

An efficient single-frequency laser-diode pumped, continuous wave (CW) ring Nd laser emitting at 1064.4 nm is demonstrated. A composite crystal (Nd:YVO4/YVO4) with un-doped ends is single end pumped by a fiber-coupled laser diode (LD) at 808 nm. A four-mirror ring cavity is deigned to keep the laser unidirectional operating, which eliminate spatial hole burning in standing-wave cavity. With the incident pump power of 31.5 W, the obtained output power is 13.6 W, with a slope efficiency of 52.6% and an optical efficiency of 43.2%. At the same time, a beam quality of M2 ∼1.1 is found. © 2010 by Astro Ltd.


Zhang X.L.,Harbin Engineering University | Li L.,Harbin Engineering University | Cui J.H.,Harbin Engineering University | Ju Y.L.,Harbin Institute of Technology | Wang Y.Z.,Harbin Institute of Technology
Laser Physics Letters | Year: 2010

In this paper we report on a laser diode end-pumped single longitudinal mode (SLM) and continuously tunable frequency Tm,Ho:YLF laser with high beam quality at room temperature. The maximal output power of single longitudinal mode is as high as 118 mW by using two uncoated fused silica etalons, which are respectively 0.1 mm and 1 mm thick. Furthermore, the output frequency of the laser can be tuned continuously over 1 GHz by only angle tuning the 1 mm thick etalon. The single longitudinal mode laser can be used as a seed laser for coherent wind measurements and differential absorption lidar systems. © 2010 by Astro Ltd.


Zhang J.,Harbin Engineering University | Zhang L.,Harbin Engineering University | Leng Z.,Harbin Engineering University | Liu S.,Harbin Institute of Technology | And 2 more authors.
Scripta Materialia | Year: 2013

18R long-period stacking ordered (LPSO) structure was introduced into Mg-Li alloys. For the investigated Mg-8Li-6Y-2Zn alloy, LPSO phase cannot be formed in the as-cast state as Mg-Y-Zn alloys, but it can be transformed from (Mg,Zn)24Y5 phase via heat treatment at 500 °C. Tensile test results indicate that the formation of 18R LPSO phase can effectively improve both the strength and plasticity of extruded Mg-8Li-6Y-2Zn alloy. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Yan M.F.,Harbin Institute of Technology | Wu Y.Q.,Harbin Institute of Technology | Liu R.L.,Harbin Engineering University
Applied Surface Science | Year: 2013

The nanocrystallized 18Ni maraging steel was plasma nitrocarburized at 460 °C for 4 h in a mixture gas of N2, H2 and C 2H5OH. The surface phase compositions of the specimens were analyzed using X-ray diffractometer. The grain shape and size, and grain boundaries in the subsurface layers of the samples were characterized by electron backscattering diffraction and transmission electron microscopy. The results show that the nitrocarburized layers are composed of α-Fe, γ′-Fe4N and FeN0.049 phases. Most α-Fe and γ′-Fe4N grains show in columnar shape. The major and minor axes of some α-Fe grains are elongated and shortened after nitrocarburizing, respectively. In the subsurface layers of the untreated and nitrocarburized specimens, the average areas of γ′-Fe4N and α-Fe grains both with a dimension of nanometer are 0.395 μm 2 and 0.397 μm2, respectively. The γ′- Fe4N grain boundaries are mainly high angle boundaries with a very small fraction of low angle boundaries. Coincidence site lattice boundaries in the subsurface layer of the untreated specimen are composed mainly of Σ3, Σ11 and Σ13b, and their fraction decreases after nitrocarburizing. © 2013 Elsevier B.V. All rights reserved.


Liu J.,Harbin Institute of Technology | Yi F.,Harbin Engineering University | Wei J.,Harbin Institute of Technology
International Journal of Bifurcation and Chaos | Year: 2010

A reaction-diffusion Gierer-Meinhardt model of morphogenesis subject to Dirichlet fixed boundary condition in the one-dimensional spatial domain is considered. We perform a detailed Hopf bifurcation analysis and steady state bifurcation analysis to the system. Our results suggest the existence of spatially nonhomogenous periodic orbits and nonconstant positive steady state solutions, which imply the possibility of complex spatiotemporal patterns of the system. Numerical simulations are carried out to support our theoretical analysis. © 2010 World Scientific Publishing Company.


Yi F.,Harbin Engineering University | Liu J.,Harbin Institute of Technology | Wei J.,Harbin Institute of Technology
Nonlinear Analysis: Real World Applications | Year: 2010

In this paper, we have investigated a homogeneous reactiondiffusion bimolecular model with autocatalysis and saturation law subject to Neumann boundary conditions. We mainly consider Hopf bifurcations and steady state bifurcations which bifurcate from the unique constant positive equilibrium solution of the system. Our results suggest the existence of spatially non-homogeneous periodic orbits and non-constant positive steady state solutions, which implies the possibility of rich spatiotemporal patterns in this diffusive biomolecular system. Numerical examples are presented to support our theoretical analysis. © 2009 Elsevier Ltd. All rights reserved.


Zhang X.,Harbin Institute of Technology | Zhang X.,Harbin Engineering University
Journal of Control Theory and Applications | Year: 2012

This paper investigates the attitude tracking and disturbance rejection problem of rigid spacecraft. Using a new matrix product, i. e., the semitensor product of matrices, the parameter uncertainties in the inertia matrix is isolated. Both the parameter uncertainties and the external disturbance are handled by robust adaptive control method. By combining the semitensor product of matrices, backstepping control methodology, and adaptive control technique, a new adaptive control law is designed. Simulation result is also presented to demonstrate the proposed design method. © 2012 South China University of Technology, Academy of Mathematics and Systems Science, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.


Du C.,Harbin Institute of Technology | Chen M.,Harbin Engineering University | Wang W.,Harbin Engineering University | Tan Q.,Harbin Institute of Technology | And 2 more authors.
Journal of Power Sources | Year: 2013

This paper describes the facile synthesis of the PtCu intermetallic nanotubes, which are obtained by a galvanic replacement reaction using Cu nanowires as templates followed by chemical etching and heat annealing. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy are used to characterize the PtCu intermetallic nanotubes. Both cyclic voltammetry and chronoamperometry results demonstrate that these PtCu nanotubes exhibit significantly high catalytic activity toward the formic acid oxidation reaction in comparison with the conventional Pt/C catalyst. Furthermore, the PtCu nanotubes show >10 times higher durability than the Pt/C catalyst in the accelerated ageing test. It is revealed that the PtCu intermetallic nanotubes have a Pt/PtCu core-shell nanostructure that combines the merits of tailorable electronic structures for core-shell nanoparticles and unique geometries for one-dimensional nanotubes, which synergistically contribute to the activity and durability. We believe that the design concept of hierarchy intermetallic nanotubes and the versatile synthetic strategy can not only be used for fuel cell catalysts but also be potentially extended to other catalysis fields. © 2013 Elsevier B.V. All rights reserved.


Han H.,Harbin Engineering University | Li B.,Harbin Institute of Technology | Shao W.,Harbin Institute of Technology
Applied Thermal Engineering | Year: 2014

Multi-objective optimal designs of high efficiency corrugated tube heat exchangers applied in nuclear plants are presented in this paper. Dimensionless corrugation pitch (p/D), dimensionless corrugation height (H/D), dimensionless corrugation radius (r/D) and Reynolds number (Re) were considered as four design parameters. The analyses of heat transfer characteristic, resistance characteristic and overall heat transfer performance for the corrugated tube were conducted based on CFD to acquire the objective functions (Nuc, fc, Nuc/Nus, fc/fs and η in this paper) for combination of process parameters. The Response surface methodology (RSM) with Central composite design (CCD) was used to identify the relationships between the objective functions and the design variables. Variance of the linear term, quadratic term and interactive term for design parameters in the response variables were analyzed. Response surface analyses were applied to visualize the effects of the interactive term. The results of optimal designs are a set of multiple optimum solutions, called 'Pareto optimal solutions'. It reveals that augmenting the heat transfer performance caused by various design parameters in the optimum situation would lead to the increase of the resistance. The optimum values of fc/fs = 1.22 and η = 1.42 are obtained in the condition of specific (fixed) Nuc/Nu s ≤ 1.2. © 2014 Elsevier Ltd. All rights reserved.


Zhang Y.,Harbin Engineering University | Jiang S.,Harbin Engineering University | Zhao Y.,Harbin Engineering University | Shan D.,Harbin Institute of Technology
International Journal of Advanced Manufacturing Technology | Year: 2014

7A09 aluminum alloy ring seat of airplane is subjected to isothermal precision forging. The influence of the different preforms on flow line, microstructures, mechanical properties, and defects of the forging is comprehensively investigated by means of experiments and FEM. Isothermal precision forging of the ring seat is implemented on the basis of three disk preforms with the height of 15, 25, and 35 mm, respectively. The experimental results indicate that the flow of metal along the radial direction increases with the increase in the height of the preform, and large plastic deformation of metal along the radial direction contributes to forming flow line of the forging. In the case of the preform with the height of 35 mm, the forging exhibits perfect profile, where there exist no defects such as underfilling and folding, while breaking of flow line frequently occurs. Furthermore, the high preform causes the forging to possess finer grain and substructure and consequently contributes to enhancing comprehensive mechanical properties. As a consequence, the preforging preform is appropriately designed so that high-quality forging with perfect flow line can be obtained by means of the optimum process procedure. © 2014 Springer-Verlag London.


Chen M.,Harbin Engineering University | Du C.,Harbin Institute of Technology | Song B.,Harbin Engineering University | Xiong K.,Harbin Institute of Technology | And 3 more authors.
Journal of Power Sources | Year: 2013

This paper reports a facile approach to prepare FePO 4 microspheres with carbon nanotube embedded (FePO 4/CNT) by a hydrothermal process, from which LiFePO 4/CNT microspheres were further obtained by chemical lithiation. The preparation procedure is simple, well reproducible, and easy to be scaled up. In addition to the desirable spherical morphology that leads to high tap density, these microspheres contain uniform and well-connected CNT networks, which remarkably enhances their electronic conductivity. Meanwhile, these materials develop a large amount of nanopores during the synthesis, giving rise to both large surface area and good electrolyte infiltration. The LiFePO 4/CNT material displays both excellent volumetric Li storage properties at high current rates (>155 mAh cm -3 at 5C), and stable charge/discharge cyclability (>90% capacity retention after 1000 charge/discharge cycles). The LiFePO 4/CNT microspheres are rather promising for high-power lithium ion batteries, and such an approach can be extended to prepare other high-performance electrode materials. © 2012 Elsevier B.V. All rights reserved.


Zhang X.,Harbin Institute of Technology | Zhang X.,Harbin Engineering University | Cheng D.,Chinese Academy of Sciences
Asian Journal of Control | Year: 2012

In this paper, we consider the attitude tracking and disturbance rejection problem of rigid spacecraft, which is subject to some disturbances generated by nonlinear exosystems. A new nonlinear internal model is designed to manipulate the uncertainties caused by external disturbances, which includes the linear internal model as a special case. A numerical example is given to illustrate the theoretical result presented in the paper. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.


Du C.,Harbin Institute of Technology | Chen M.,Harbin Engineering University | Wang L.,Harbin Engineering University | Yin G.,Harbin Institute of Technology
Journal of Materials Chemistry | Year: 2011

This paper reports the facile fabrication of Si@C core-shell nanocomposites by covalently grafting aniline monomer onto the surface of silicon nanoparticles, followed by a carbonizing process. Our covalently-functionalizing approach can lead to a uniform carbon coating with a tunable thickness and is low cost, environmentally friendly and easily scaled up. The Si@C nanocomposite was employed as an anode material for lithium-ion batteries (LIBs), showing a high initial reversible capacity of >1300 mA h g-1 as well as a good cycling stability. The enhanced performance is attributed to the fact that the uniform and elastic carbon coating can efficiently increase the electronic conductivity and accommodate severe volume changes of the Si particles. This Si@C nanocomposite exhibits great potential as an anode material in LIBs, and the fabrication strategy can be extended to prepare other carbon-coated core-shell nanocomposites. © 2011 The Royal Society of Chemistry.


Zhang X.L.,Harbin Engineering University | Li L.,Harbin Engineering University | Liu Y.F.,Harbin Engineering University | Peng Y.F.,Harbin Engineering University | And 2 more authors.
Laser Physics Letters | Year: 2011

In this paper we first report on a continuous wave laser diode end-pumped passively Q-switched Tm,Ho:YLF laser at 2053 nm with Cr:ZnS crystal as a saturable absorber near room temperature. The pulsewidth is very stable at about 1.25 μs, the pulsed energy is about 4 μJ, and the pulse repetition is between 1.3 and 2.6 kHz when the pump power is changed from 1.0 to 1.9 W. The nearly diffraction-limited and stable long pulse laser can be used to laser lidar systems for accurate wind velocity measurements. © 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.


Ge B.,Harbin Engineering University | Ge B.,Harbin Institute of Technology | Xue X.,Harbin Institute of Technology | Zhou Q.,Northeast Forestry University
Nonlinear Analysis: Real World Applications | Year: 2011

We studied a nonlinear Dirichlet problem driven by the p(x)-Laplacian and having a nonsmooth potential (hemivariational inequalities). Using a variational method combined with suitable truncation techniques based on nonsmooth critical point theory for locally Lipschitz function, we proved the existence of at least five solutions under the suitable conditions. © 2011 Elsevier Ltd. All rights reserved.


Ge B.,Harbin Engineering University | Zhou Q.-M.,Northeast Forestry University | Xue X.-P.,Harbin Institute of Technology
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2012

In this paper, we consider the differential inclusion in ℝ N involving the p(x)-Laplacian of the type, where p: ℝ N → ℝ is Lipschitz continuous function satisfying some given assumptions. The approach used in this paper is the variational method for locally Lipschitz functions. Under suitable oscillatory assumptions on the potential F at zero or at infinity, we show the existence of infinitely many solutions of (P). We also establish a Bartsch-Wang type compact embedding theorem for variable exponent spaces. © 2012 Springer Basel AG.


Guo Y.,Harbin Engineering University | Huang J.,Nuclear Power Institute of China | Xia G.,Harbin Engineering University | Zeng H.,Harbin Engineering University
Annals of Nuclear Energy | Year: 2010

In this paper, the behavior of two-phase flow instability of a twin-channel system is studied experimentally. The two-phase flow instability between twin channels (FIBT) was observed in the experiments at three different system pressures, different inlet resistance coefficients and nonuniform heating condition. The instability boundaries of the twin-channel system are obtained in the phase plane of the subcooling and phase change number. The influences of inlet resistance, system pressure and nonuniform heating are obtained. In the end the numerical simulation results based on RELAP5/MOD3.4 code are also discussed. © 2010 Elsevier Ltd. All rights reserved.


Ru X.,Harbin Engineering University | Staehle R.W.,Nuclear Power Institute of China
Corrosion | Year: 2013

This review assesses past experiences from superheated fossil plants, supercritical fossil plants, superheated nuclear plants, and light water reactors from the late 1940s until the present. Data from the development and operation of these plants are directly applicable to supercritical water reactor (SCWR) plants being developed currently. This past work can be applied to the development of current designs in the choice of materials, temperature dependencies, effects of stress, and effects of environments on materials. Some of the past data from light water reactor (LWR) technology can be extrapolated into the present SCWR regimes. The past data are in good agreement among the various previous investigators. These past data are considered with respect to specific components in SCWR: fuel cladding, reactor structurals, reactor vessels, and feed water heaters. Choosing materials for the SCWR applications must recognize that the materials at nominal outlet temperatures are in a dynamic thermal range, i.e., in the nuclear superheat and fossil superheat range, the atomic structures of materials change significantly and change properties such as ductility. It is also possible that compositions and structures of grain boundaries can change, for example, the susceptibility to SCC. The surface temperatures on fuel cladding will be significantly higher than the outlet temperature, and both temperatures will exceed, substantially, the outlet temperatures of present water-cooled plants. Past isothermal data directed toward core structures may not be relevant to the same alloy as fuel cladding. The outlet temperature is useful for considering core structural materials but not for fuel elements, owing to an inevitably high film drop. SCW environments are expected to produce extensive SCC, which differs from past experience. Finally, past data were reanalyzed and additional useful insights were obtained. © 2013, NACE International.


Cheng B.-Z.,Daqing Normal University | Zhao C.-H.,Harbin Engineering University
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2013

The high dimensionality of hyperspectral image increases information, but it also leads to the question of dimensionality curse. There are several problems to be solved in reducing dimension, eliminating redundancy of bands, and suppressing background interferences during hyperspectral anomaly targets detection. Aiming at the problems, this paper proposes a new anomaly target detection algorithm of hyperspectral image based on particle swarm optimization (PSO) clustering. Firstly, the algorithm optimizes the traditional-means clustering by using PSO method, the original hyperspectral image is divided for bands subset class by PSO clustering while the features of hyperspectral image bands aren't changed, and those bands with similar features are clustering; Then, the feature information of all band subsets is extracted by using the principal component analysis, which makes the information of anomaly target with highlight and suppresses background interference; At last, the optimal band subsets are achieved by fourth-order cumulant of principal component in band subsets, and anomaly detection is carried on by the kernel RX. The results show that the proposed algorithm was higher precision and lower false alarm probability.


Zhang A.M.,Harbin Engineering University | Cui P.,Harbin Engineering University | Wang Y.,Naval Academy of Armament
Experiments in Fluids | Year: 2013

Experiments were conducted where the underwater bubble oscillates between two boundaries, a free surface and a horizontal rigid wall. The motion features of both the bubble and the free surface were investigated, via the consideration of two key factors, i.e., the non-dimensional distances from the bubble to the two boundaries. To support the investigation, experiments were conducted in the first place where the bubble oscillates near only one of the two boundaries. Then the other boundary was inserted at different positions to observe the changes in the motion features, including the types, maximum speed and height of the water spike and skirt, the form and speed of the jets, and bubble shapes. Correspondence is found between the motion features of the free surface and different stages of bubble oscillation. Intriguing details such as gas torus around the jet, double jets, bubble entrapment, and microjet of the water spike, etc., are observed. © 2013 Springer-Verlag Berlin Heidelberg.


Liu L.,Harbin Engineering University | Namikoshi T.,Kitami Institute of Technology | Zang Y.,Niigata University | Aoki T.,Niigata University | And 6 more authors.
Journal of the American Chemical Society | Year: 2013

A novel, highly selective photocyclic aromatization (SCAT) of π-conjugated polymers from phenylacetylene having two hydroxyl groups to exclusively yield a 1,3,5-trisubstituted benzene derivative was developed, and its success was confirmed by 1H NMR, GPC, and TOF-MS. The SCAT reaction has many unique characteristics. (1) It is a quantitative reaction: it gave only the corresponding cyclic trimer, i.e., a 1,3,5-trisubstituted benzene derivative, quantitatively (100%). No byproducts were produced under the best conditions. (2) It is an intramolecular reaction: it occurred between three adjacent monomer units in one macromolecule. (3) It is a stereospecific and topochemical or template reaction: the reactivity strongly depended on the configuration and conformation of the starting polymer substrates. (4) It is a photoreaction: high selectivity (100%) was observed only by the use of visible light irradiation, not by heating. (5) It is a solid-state reaction: high selectivity (100%) was observed only in the solid state, not in solution. In addition, (6) the resulting cyclic trimers could form a self-supporting membrane, despite their low molecular weights. This new approach resulted in a new class of supramolecular polymers consisting of a 1,3,5-trisubstituted benzene derivative, numbers of which were linearly linked by hydrogen bonds and stacked benzene derivatives. Since SCAT has such high selectivities and is useful for the preparation of a self-supporting supramolecular polymer membrane, many applications can be expected. © 2012 American Chemical Society.


Schaller G.R.,University of Kiel | Topic F.,University of Jyväskylä | Rissanen K.,University of Jyväskylä | Okamoto Y.,Nagoya University | And 2 more authors.
Nature Chemistry | Year: 2014

As long as 50 years ago theoretical calculations predicted that Möbius annulenes with only one π surface and one edge would exhibit peculiar electronic properties and violate the Hückel rules. Numerous synthetic attempts notwithstanding, the first singly twisted Möbius annulene was not prepared until 2003. Here we present a general, rational strategy to synthesize triply or even more highly twisted cyclic π systems. We apply this strategy to the preparation of a triply twisted [24]dehydroannulene, the structure of which was confirmed by X-ray analysis. Our strategy is based on the topological transformation of 'twist' into 'writhe'. The advantage is twofold: the product exhibits a lower degree of strain and precursors can be designed that inherently include the writhe, which, after cyclization, ends up in the Möbius product. With our strategy, triply twisted systems are easier to prepare than their singly twisted counterparts. © 2014 Macmillan Publishers Limited.


Xu G.D.,Harbin Engineering University | Wu G.X.,University of London
Engineering Analysis with Boundary Elements | Year: 2013

The dynamic performance of a rigid foil with harmonic vertical and rotational motions in fluid flow has been studied through velocity potential theory. A boundary element based time stepping scheme is introduced to simulate the flow around the foil and the vortex wake. The body surface condition is satisfied on the exact foil surface and the motion and deformation of the wake sheet shed at the trailing edge is tracked. Kelvin condition is satisfied and a Kutta condition for the unsteady motion is proposed to circumvent the singularity at the trailing edge. Point vortex, which is reduced from wake vortex dipole, is introduced to approximate the vorticity. The performance of foil NACA0012 with harmonic vertical and rotational motions are studied extensively; the propulsion/swimming mode, energy harvesting mode and the flying mode are analysed in detail. © 2013 Published by Elsevier Ltd.


Zhou R.,Harbin Engineering University | Khemmarat S.,University of Massachusetts Amherst | Gao L.,University of Massachusetts Amherst
Proceedings of the ACM SIGCOMM Internet Measurement Conference, IMC | Year: 2010

Hosting a collection of millions of videos, YouTube offers several features to help users discover the videos of their interest. For example, YouTube provides video search, related video recommendation and front page highlight. The understanding of how these features drive video views is useful for creating a strategy to drive video popularity. In this paper, we perform a measurement study on data sets crawled from YouTube and find that the related video recommendation, which recommends the videos that are related to the video a user is watching, is one of the most important view sources of videos. Despite the fact that the YouTube video search is the number one source of views in aggregation, the related video recommendation is the main source of views for the majority of the videos on YouTube. Furthermore, our results reveal that there is a strong correlation between the view count of a video and the average view count of its top referrer videos. This implies that a video has a higher chance to become popular when it is placed on the related video recommendation lists of popular videos. We also find that the click through rate from a video to its related videos is high and the position of a video in a related video list plays a critical role in the click through rate. Finally, our evaluation of the impact of the related video recommendation system on the diversity of video views indicates that the current recommendation system helps to increase the diversity of video views in aggregation. Copyright 2010 ACM.


Wang D.,Harbin Engineering University | Wang D.,Automobile Management Institute of PLA | Ma C.-G.,Harbin Engineering University | Wu P.,Harbin Engineering University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In DBSec'11, Li et al. showed that Kim and Chung's password-based remote user authentication scheme is vulnerable to various attacks if the smart card is non-tamper resistant. Consequently, an improved version was proposed and claimed that it is secure against smart card security breach attacks. In this paper, however, we will show that Li et al.'s scheme still cannot withstand offline password guessing attack under the non-tamper resistance assumption of the smart card. In addition, their scheme is also prone to denial of service attack and fails to provide user anonymity and forward secrecy. Therefore, a robust scheme with a brief analysis is presented to overcome the identified drawbacks. © 2012 IFIP International Federation for Information Processing.


Ma C.-G.,Harbin Engineering University | Wang D.,Harbin Engineering University | Wang D.,Automobile Management Institute of PLA | Zhang Q.-M.,Harbin Engineering University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Anonymity is one of the important properties of remote authentication schemes to preserve user privacy. Recently, Sood et al. showed that Wang et al.'s dynamic ID-based remote user authentication scheme fails to preserve user anonymity and is vulnerable to various attacks if the smart card is non-tamper resistant. Consequently, an improved version of dynamic ID-based authentication scheme was proposed and claimed that it is efficient and secure. In this paper, however, we will show that Sood et al.'s scheme still cannot preserve user anonymity under their assumption. In addition, their scheme is also vulnerable to the offline password guessing attack and the stolen verifier attack. To remedy these security flaws, we propose an enhanced authentication scheme, which covers all the identified weaknesses of Sood et al.'s scheme and is more secure and efficient for practical application environment. © 2012 Springer-Verlag.


Peng R.,Jiangsu University | Peng R.,University of Minnesota | Yi F.,Harbin Engineering University
Physica D: Nonlinear Phenomena | Year: 2013

Identifying the epidemic risk for infectious disease is crucial in order to effectively perform control measures. In a series of our work, from an analytical aspect we study the effects of epidemic risk and population movement on the spatiotemporal transmission of infectious disease via an SIS epidemic reaction-diffusion model proposed by Allen et al. (2008) in [36]. In Allen et al. (2008) [36], Peng (2009) [37], it was assumed that the habitat of the populations consists of only the low and high risk areas. The present paper concerns a more complicated heterogeneous environment where the moderate risk area occurs, and deals with two cases: (i) only the moderate and high risk areas exist; (ii) the low, moderate and high risk areas coexist. In each case, we rigorously determine the asymptotic profile of the positive steady state (i.e., the endemic equilibrium) as the migration rate of either the susceptible or infected population tends to zero. Our results show how epidemic risk and population movement affect the spatial distribution of infectious disease and thereby suggest important implications for predicting the patterns of disease occurrence and designing optimal control strategies. Numerical simulations are carried out to support the theoretical results. © 2013 Elsevier B.V. All rights reserved.


Wang Q.,Harbin Engineering University | Yan J.,Harbin Engineering University | Wang Y.,Harbin Engineering University | Ning G.,China University of Petroleum - Beijing | And 5 more authors.
Carbon | Year: 2013

A carbon material consisting of hollow carbon spheres anchored on the surface of carbon nanotubes (CNT-HCS) has been synthesized by an easy chemical vapor deposition process using a CNT-MnO2 hybrid as template. An electrode made of this material exhibits a maximum specific capacitance of 201.5 F g-1 at 0.5 A g-1 and excellent rate performance (69% retention ratio at 20 A g-1). It has impressive cycling stability with 90% initial capacitance retained after 5000 cycles at 5 A g-1 in 6 mol L-1 KOH. Symmetric supercapacitors based on CNT-HCS achieve a maximum energy density of 11.3 W h kg-1 and power density of 11.8 kW kg-1 operated within a wide potential range of 0-1.6 V in 1.0 mol L-1 Na2SO4 solution. © 2012 Elsevier Ltd. All rights reserved.


Wang D.,Harbin Engineering University | Wang D.,Automobile Management Institute of PLA | Ma C.-G.,Harbin Engineering University
Journal of China Universities of Posts and Telecommunications | Year: 2012

With the broad implementations of the electronic business and government applications, robust system security and strong privacy protection have become essential requirements for remote user authentication schemes. Recently, Chen et al. pointed out that Wang et al.'s scheme is vulnerable to the user impersonation attack and parallel session attack, and proposed an enhanced version to overcome the identified security flaws. In this paper, however, we show that Chen et al.'s scheme still cannot achieve the claimed security goals and report its following problems: (1) It suffers from the offline password guessing attack, key compromise impersonation attack and known key attack; (2) It fails to provide forward secrecy; (3) It is not easily repairable. As our main contribution, a robust dynamic ID-based scheme based on non-tamper resistance assumption of the smart cards is presented to cope with the aforementioned defects, while preserving the merits of different related schemes. The analysis demonstrates that our scheme meets all the proposed criteria and eliminates several grave security threats that are difficult to be tackled at the same time in previous scholarship. © 2012 The Journal of China Universities of Posts and Telecommunications.


Wang Q.,Harbin Engineering University | Shi D.,Harbin Engineering University | Liang Q.,Harbin Engineering University | Shi X.,China Academy of Engineering Physics
Composites Part B: Engineering | Year: 2016

The vibrations of functionally graded circular plates, annular plates, and annular, circular sectorial plates have been traditionally treated as different boundary value problems, which results in numerous specific solution algorithms and procedures. It is the problem itself that has been an overwhelming task for a new researcher or application engineer to comprehend. Furthermore each type of plate usually needs treating separately when different boundary conditions are involved. In this paper, a unified method is presented for the vibration analysis of the plates mentioned above with general boundary conditions based on the first-order shear deformation theory and Ritz procedure. The material properties are assumed to vary continuously through the thickness according to the general four-parameter power-law distribution. Regardless of the shapes of the plates and the types of boundary conditions, the displacements of the plates are described as an improved Fourier series expansion which is composed of a double Fourier cosine series and several auxiliary functions. As an innovative point of this work, the auxiliary functions are introduced to eliminate all the relevant discontinuities with the displacement and its derivatives at the boundaries and to accelerate the convergence of series representations. The accuracy, reliability and versatility of the current solution are fully demonstrated and verified through numerical examples involving plates with various shapes and boundary conditions. Some new results of functionally graded circular, annular and sector plates with various boundary conditions are presented, which may serve as datum solutions for future computational methods. In addition, the influence of boundary conditions, the material and geometric parameters on the vibration characteristics of the plates are also reported. © 2015 Elsevier Ltd. All Rights Reserved.


Liu Y.,Harbin Engineering University | Tang C.,Tianjin Polytechnic University
Guangxue Xuebao/Acta Optica Sinica | Year: 2013

The holographic camera system for research and analysis on marine microorganisms and particles has a wide application prospect. Because of the special imaging technique (the holographic imaging technology) and the special imaging environment (seabed), there are a variety of different oblique stripe noises in the holograms. The existence of oblique stripe noises seriously affect quality of reconstructed image of the marine biological hologram and further processing, and the present methods for common stripe noise are no longer suitable. An effective method is proposed to deal with the oblique stripe noises. For the periodic oblique stripe noise, the local threshold method is adopted to find out the frequency center of the noise, and the Gaussian notch filter is utilized to eliminate the noise. For the aperiodic oblique stripe noise, the linear equation is used to simulate the bright line of the noise in the frequency domain, and the partial notch filter is exploited to depress the noise. Simulation results illustrate that the proposed method can filter out the periodic oblique stripe noise completely as well as the aperiodic oblique stripe noise mostly, and the useful information of the holograms can be kept.


Zhang S.,Harbin Engineering University | Gai S.,Harbin Engineering University | He F.,Harbin Engineering University | Ding S.,Xi'an Jiaotong University | And 2 more authors.
Nanoscale | Year: 2014

The easy aggregation nature of ferromagnetic nanoparticles (NPs) prepared by conventional routes usually leads to a large particle size and low loading, which greatly limits their applications to the reduction of 4-nitrophenol (4-NP). Herein, we developed a novel in situ thermal decomposition and reduction strategy to prepare Ni nanoparticles/silica nanotubes (Ni/SNTs), which can markedly prevent the aggregation and growth of Ni NPs, resulting in an ultra-small particle size (about 6 nm), good dispersion and especially high loading of Ni NPs. It was found that Ni/SNTs, which have a high specific surface area (416 m2g-1), exhibit ultra-high catalytic activity in the 4-NP reduction (complete reduction of 4-NP within only 60 s at room temperature), which is superior to most noble metal (Au, Pt, and Pd) supported catalysts. Ni/SNTs still showed high activity even after re-use for several cycles, suggesting good stability. In particular, the magnetic property of Ni/SNTs makes it easy to recycle for reuse. This journal is © the Partner Organisations 2014.


Tang C.,Tianjin Polytechnic University | Hussain A.,Harbin Engineering University
IEEE Transactions on Vehicular Technology | Year: 2015

Vehicle surveillance in complex dark traffic scenes has been a key research topic, as the background is dramatically altered due to the reflections from headlights on normal, snowy, and rainy roads. Under dark conditions, a vehicle's headlights and rear lights are used for foreground extraction. The presented algorithm provides several steps, including the detection, pairing, and tracking of headlights and rear lights. First, the headlights are automatically extracted by a novel approach called azimuthally blur, which uses the exponentially attenuating nature of reflected light. This approach is robust on highly reflective scenes because it makes the headlights orthogonal to the reflections. The headlights are then paired by partitioning the image into subgroups such that in each group, the headlights remain equidistant. The optimized tracker based on the maximum a posteriori (MAP) probability estimator is employed for further analysis such as speed estimation. This whole scheme is computationally inexpensive and can be deployed in application-specific integrated circuits. The proposed approach has outperformed state-of-the-art methods in challenging unlit traffic scenes. © 1967-2012 IEEE.


Wang D.,Harbin Engineering University | Wang D.,Automobile Management Institute of PLA | Ma C.-G.,Harbin Engineering University
Information Fusion | Year: 2013

Understanding security failures of cryptographic protocols is the key to both patching existing protocols and designing future schemes. The design of secure remote user authentication schemes based on elliptic curve crypto-graphy (ECC) for mobile applications is still quite a challenging problem, though many schemes have been published lately. In this paper, we analyze an efficient ID-based scheme for mobile client-server environment without the MapToPoint function introduced by He et al. in 2012. This proposal attempts to overcome many of the well known security and efficiency shortcomings of previous schemes, and it also carries a claimed proof of security in the random oracle model. However, notwithstanding its formal security arguments, we show that He et al.'s protocol even cannot attain the basic goal of mutual authentication by demonstrating its vulnerabilities to reflection attack and parallel session attack. Besides these two security vulnerabilities, their scheme also suffers from some practical pitfalls such as user anonymity violation and clock synchronization problem. In addition, we carry out an investigation into their security proof and propose some changes to the scheme so that it can achieve at least its basic security goal, in the hope that similar mistakes are no longer made in the future. © 2013 Elsevier B.V. All rights reserved.


Wang Q.,Hong Kong Polytechnic University | Shi W.,Hong Kong Polytechnic University | Shi W.,Wuhan University | Wang L.,Harbin Engineering University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

There is a type of algorithm for subpixel mapping (SPM), namely, the soft-then-hard SPM (STHSPM) algorithm that first estimates soft attribute values for land cover classes at the subpixel scale level and then allocates classes (i.e., hard attribute values) for subpixels according to the soft attribute values. This paper presents a novel class allocation approach for STHSPM algorithms, which allocates classes in units of class (UOC). First, a visiting order for all classes is predetermined, and the number of subpixels belonging to each class is calculated using coarse fraction data. Then, according to the visiting order, the subpixels belonging to the being visited class are determined by comparing the soft attribute values of this class, and the remaining subpixels are used for the allocation of the next class. The process is terminated when each subpixel is allocated to a class. UOC was tested on three remote sensing images with five STHSPM algorithms: back-propagation neural network, Hopfield neural network, subpixel/pixel spatial attraction model, kriging, and indicator cokriging. UOC was also compared with three existing allocation methods, i.e., linear optimization technique (LOT), sequential assignment in units of subpixel (UOS), and a method that assigns subpixels with highest soft attribute values first (HAVF). Results show that for all STHSPM algorithms, UOC is able to produce higher SPM accuracy than UOS and HAVF; compared with LOT, UOC is able to achieve at least comparable accuracy but needs much less computing time. Hence, UOC provides an effective and real-time class allocation method for STHSPM algorithms. © 1980-2012 IEEE.


Zhang A.-M.,Harbin Engineering University | Wang S.-P.,Harbin Engineering University | Huang C.,China Academy of Engineering Physics | Wang B.,China Academy of Engineering Physics
European Journal of Mechanics, B/Fluids | Year: 2013

Numerical and experimental methods are combined in this paper to study the bubble dynamics generated by an underwater charge explosion with different initial charge shape, detonating styles and boundary conditions. Outdoor experiments are carried out to employ sunlight with the assistant of lamplight to get clearer pictures of bubble motion. The results show that the charge detonating stage is not finished instantly but takes some time to explode fully. The explosion begins from its detonating end and finishes at the other end, which results in its uneven distribution of initial normal velocity. So instead of following the traditional method of treating the charge explosion instantly, a real charge explosion model is built in this paper with the combination of LS-DYNA and the boundary element method (BEM). LS-DYNA is used to solve the charge initial detonation and the BEM to solve its subsequent bubble motion. The linking relationship between these two methods is modeled. The convergence study has been firstly taken with different meshes. In this paper, charges with a different slenderness ratio from 0.99 to 20 are chosen to carry out the experiments and their corresponding numerical results are put forward. It can be found in both experimental and numerical results that the initial charge shape and its detonating style would affect its following bubble dynamic behavior. When the cylindrical charge is horizontally installed and end detonated, an oblique jet leaned to the detonating end would be formed and a horizontal migration process is also observed during the whole bubble pulsating stage. The bubble dynamic behaviors near different solid boundaries are further studied and the numerical results coincide well with the experimental ones. © 2013 Elsevier Masson SAS. All rights reserved.


Wang Q.,Hong Kong Polytechnic University | Shi W.,Hong Kong Polytechnic University | Shi W.,Wuhan University | Wang L.,Harbin Engineering University
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014

Subpixel mapping (SPM) is a technique for predicting the spatial distribution of land cover classes in remote sensing images at a finer spatial resolution level than those of the input images. Indicator cokriging (ICK) has been found to be an effective and efficient SPM method. The accuracy of this model, however, is limited by insufficient constraints. In this paper, the accuracy of the ICK-based SPM model is enhanced by using additional information gained from multiple shifted images (MSIs). First, each shifted image is utilized to compute the conditional probability of class occurrence at any fine spatial resolution pixel (i.e., subpixel) using ICK, and a set of conditional probability maps for all classes are generated for each image. The multiple ICK-derived conditional probability maps are then integrated, according to the estimated subpixel shifts of MSI. Lastly, class allocation at the subpixel scale is implemented to produce SPM results. The proposed algorithm was tested on two synthetic coarse spatial resolution remote sensing images and a set of real Moderate Resolution Imaging Spectroradiometer (MODIS) data. It was evaluated both visually and quantitatively. The experimental results showed that more accurate SPM results can be generated with MSI than with a single observed coarse image in conventional ICK-based SPM. In addition, the accuracy of the proposed method is higher than that of the existing Hopfield neural network (HNN)-based SPM and the HNN with MSI. © 2008-2012 IEEE.


Zhang A.-M.,Harbin Engineering University | Yang W.-S.,Ship Research Institute | Huang C.,China Academy of Engineering Physics | Ming F.-R.,Harbin Engineering University
Computers and Fluids | Year: 2013

Underwater explosion detonated by column charge can generate exceedingly high-pressure shock wave, bubble pulsing and high-speed jet formed by bubble. Its physical course involves many complicated problems such as transient state, high temperature and high pressure, large distortion and multi-medium flow. For this reason, axisymmetric Smoothed Particle Hydrodynamics (SPHs) numerical model was established combined with Boundary Element Method (BEM) to simulate the whole process of underwater explosion detonated by column charge in this paper. Calculation results of various phases such as shock wave propagation, bubble pulsing and jet formation agree well with the experiment values. In this study, column charge detonation and bubble jet are successfully simulated via axisymmetric SPH method. The calculation results are still of highly precise at the symmetrical axis, verifying the feasibility of the axisymmetric SPH method established in this paper in the computation of three-dimensional underwater explosion, bubble jet and other physical problems. Meanwhile, axisymmetric SPH method and BEM are successfully combined in this paper to fully utilize their advantages, which is favorable in the solution of other hydrodynamic problems. © 2012 Elsevier Ltd.


Ma C.-G.,Harbin Engineering University | Wang D.,Harbin Engineering University | Wang D.,Automobile Management Institute of PLA | Zhao S.-D.,Harbin Engineering University
International Journal of Communication Systems | Year: 2014

Understanding security failures of cryptographic protocols is the key to both patching existing protocols and designing future schemes. In this paper, we analyze two recent proposals in the area of password-based remote user authentication using smart cards. First, we point out that the scheme of Chen et al. cannot achieve all the claimed security goals and report its following flaws: (i) it is vulnerable to offline password guessing attack under their nontamper resistance assumption of the smart cards; and (ii) it fails to provide forward secrecy. Then, we analyze an efficient dynamic ID-based scheme without public-key operations introduced byWen and Li in 2012. This proposal attempts to overcome many of the well-known security and efficiency shortcomings of previous schemes and supports more functionalities than its counterparts. Nevertheless, Wen-Li's protocol is vulnerable to offline password guessing attack and denial of service attack, and fails to provide forward secrecy and to preserve user anonymity. Furthermore, with the security analysis of these two schemes and our previous protocol design experience, we put forward three general principles that are vital for designing secure smart-card-based password authentication schemes: (i) public-key techniques are indispensable to resist against offline password guessing attack and to preserve user anonymity under the nontamper resistance assumption of the smart card; (ii) there is an unavoidable trade-off when fulfilling the goals of local password update and resistance to smart card loss attack; and (iii) at least two exponentiation (respectively elliptic curve point multiplication) operations conducted on the server side are necessary for achieving forward secrecy. The cryptanalysis results discourage any practical use of the two investigated schemes and are important for security engineers to make their choices correctly, whereas the proposed three principles are valuable to protocol designers for advancing more robust schemes. © 2012 John Wiley & Sons, Ltd.


Wang L.,Harbin Engineering University | Wang Q.,Harbin Engineering University | Wang Q.,University of Hong Kong
IEEE Geoscience and Remote Sensing Letters | Year: 2013

Subpixel mapping (SPM) is a promising technique to increase the spatial resolution of land cover maps. Markov random field (MRF)-based SPM has the advantages of considering spatial and spectral constraints simultaneously. In the conventional MRF, only the spectral information of one observed coarse spatial resolution image is utilized, which limits the SPM accuracy. In this letter, supplementary information from subpixel shifted remote sensing images (SSRSI) is used with MRF to produce more accurate SPM results. That is, spectral information from SSRSI is incorporated into the likelihood energy function of MRF to provide multiple spectral constraints. Simulated and real images were tested with the subpixel/pixel spatial attraction model, Hopfield neural networks (HNNs), HNN with SSRSI, image interpolation then hard classification, conventional MRF, and proposed MRF with SSRSI based SPM methods. Results showed that the proposed method can generate the most accurate SPM results among these methods. © 2004-2012 IEEE.


Zubair M.,Harbin Engineering University | Zubair M.,Sudan University of Science and Technology | Zhijian Z.,Harbin Engineering University
Safety Science | Year: 2013

In the field of Living Probabilistic Safety Assessment (LPSA) the reliability data updating is an important factor. In risk analysis equipment failure data is needed to estimate the frequencies of events contributing to risk posed by a facility. Five years data of Emergency Diesel Generator (EDG) of Daya Bay Nuclear Power Plant (NPP) has been studied in this paper. The data updating process has been done by using two methods (i.e.) classical method and Bayesian method. The aim of using these methods is to calculate operational failure rate (λ) and demand failure probability (p). The results show that operational failure rate is 1.7E-3 per hour and demand failure probability is 2.4E-2 per day of Daya Bay NPP. By comparing the results obtain from classical and Bayesian method with EDF (Electric De France) it is concluded that the design and construction of Daya Bay NPP is very different with EDF so reliability parameters used in Daya Bay NPP is based on classical method. © 2013 Elsevier Ltd.


Yu H.,Jiangsu University of Science and Technology | Ni J.,University of Iowa | Zhao J.,Harbin Engineering University
Neurocomputing | Year: 2013

In DNA microarray data, class imbalance problem occurs frequently, causing poor prediction performance for minority classes. Moreover, its other features, such as high-dimension, small sample, high noise etc., intensify this damage. In this study, we propose ACOSampling that is a novel undersampling method based on the idea of ant colony optimization (ACO) to address this problem. The algorithm starts with feature selection technology to eliminate noisy genes in data. Then we randomly and repeatedly divided the original training set into two groups: training set and validation set. In each division, one modified ACO algorithm as a variant of our previous work is conducted to filter less informative majority samples and search the corresponding optimal training sample subset. At last, the statistical results from all local optimal training sample subsets are given in the form of frequence list, where each frequence indicates the importance of the corresponding majority sample. We only extracted those high frequency ones and combined them with all minority samples to construct the final balanced training set. We evaluated the method on four benchmark skewed DNA microarray datasets by support vector machine (SVM) classifier, showing that the proposed method outperforms many other sampling approaches, which indicates its superiority. © 2012 Elsevier B.V.


Zhang J.,University of New South Wales | Zhang J.,Harbin Engineering University | Sathi Z.M.,University of New South Wales | Luo Y.,University of New South Wales | And 2 more authors.
Optics Express | Year: 2013

We demonstrate a broadband optical emission from Bi/Er codoped fiber and a single 830nm laser diode pump. The ultra-broadband mechanism is studied and discussed in details based on a combination of experimental measurements, including luminescence, differential luminescence and ESA, on fiber samples of different Bi and Er concentrations. The Er co-doping in Bi doped fiber is found to be effective for broadband emission, by enhancing not only luminescence at C and L bands but also that at O and shorter wavelength bands. The luminescence intensity between 1100 and 1570nm is over -45dBm/5nm in single mode fiber using a few meters of Bi/Er co-doped fiber and offers a modest ~40dB dynamic range and a broad bandwidth of ~470nm for an OSA based spectral measurement. © 2013 Optical Society of America.


Liu Y.,Shenyang Normal University | Drew M.G.B.,University of Reading | Wang J.,Harbin Engineering University | Zhang M.,Harbin Engineering University
Journal of Magnetism and Magnetic Materials | Year: 2010

LaMn and LaCo doped barium hexaferrites of formula Ba (1-x)LaxFe(12-x)MxO19 (M=Mn, Co) (x=0.05 to 0.40) were prepared with an improved co-precipitation/ molten salt method. For the synthesis, aqueous solutions of the appropriate metal chlorides were prepared in the ratio required except that the initial mole ratio of Fe and dopants to Ba was chosen to be 11:1, and then mixed with excess Na2CO3. The solutions were then cooled, filtered off, dried, then mixed with KCl flux, and heated at 450 °C and for 2 h. The temperature was then raised to 950 °C and kept for 4 h, then cooled. This new synthesis method, which employs a lower temperature and shorter reaction time, gives products with improved crystallinity and purity while the saturation magnetization and coercivity values are comparable with those synthesized via the high temperature method. © 2010 Elsevier B.V. All rights reserved.


Ren Y.-L.,Harbin Engineering University | Wu H.-Y.,Harbin Engineering University | Lu M.-M.,Beijing Institute of Technology | Chen Y.-J.,Harbin Engineering University | And 5 more authors.
ACS Applied Materials and Interfaces | Year: 2012

This paper presents for the first time a successful synthesis of quaternary nanocomposites consisting of graphene, Fe3O4@Fe core/shell nanopariticles, and ZnO nanoparticles. Transmission electron microscopy measurements show that the diameter of the Fe3O 4@Fe core/shell nanoparitcles is about 18 nm, the Fe 3O4 shell's thickness is about 5 nm, and the diameter of ZnO nanoparticles is in range of 2-10 nm. The measured electromagnetic parameters show that the absorption bandwidth with reflection loss less than -20 dB is up to 7.3 GHz, and in the band range more than 99% of electromagnetic wave energy is attenuated. Moreover, the addition amount of the nanocomposites in the matrix is only 20 wt %. Therefore, the excellent electromagnetic absorption properties with lightweight and wide absorption frequency band are realized by the nanocomposites. © 2012 American Chemical Society.


Liu Y.,Shenyang Normal University | Drew M.G.B.,University of Reading | Wang J.,Harbin Engineering University | Zhang M.,Harbin Engineering University
Journal of Magnetism and Magnetic Materials | Year: 2010

The synthesis of hexagonal barium ferrite (BaFe12O19) was studied under hydrothermal conditions by a method in which a significant amount of ferrous chloride was introduced alongside ferric chloride among the starting materials. Though all of the Fe2+ ions in the starting material were converted to Fe3+ ions in the final product, Fe2+ was confirmed to participate differently from the Fe3+ used in the conventional method in the mechanism of forming barium ferrite. Indeed the efficiency of the synthesis and the quality of the product and the lack of impurities such as Fe2O3 and BaFe2O4 were improved when Fe2+ was included. However, the amount of ferrous ions that could be included to obtain the desired product was limited with an optimum ratio of 2:8 for FeCl2/FeCl3 when only 2 h of reaction time were needed. It was also found that the role of trivalent Fe3+ could be successfully replaced by Al3+. Up to 50% of the iron could be replaced by Al3+ in the reactants to produce Al-doped products. It was also found that the ratio of Fe2+/M3+ could be increased in the presence of Al3+ to produce high quality barium ferrite. © 2009 Elsevier B.V.


Li X.,CAS Changchun Northeast Institute of Geography and Agroecology | Wang L.,Harbin Engineering University | Jia X.,University of New South Wales
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012

Extended support vector machines (ESVM) was introduced recently for spectral unmixing. It models a class using a group of representative spectra to accommodate within class spectral variation. This paper presents a further geometry analysis of this method, and an improved ESVM is developed, which takes into account both within-class spectral variability and within each mixed case. The experiments illustrate that the new proposed algorithm can obtain more realistic unmixing results. © 2012 IEEE.


Zhang L.,Harbin Engineering University | Zhen X.,University of Western Ontario | Shao L.,University of Sheffield
IEEE Transactions on Image Processing | Year: 2014

High-level image representations have drawn increasing attention in visual recognition, e.g., scene classification, since the invention of the object bank. The object bank represents an image as a response map of a large number of pretrained object detectors and has achieved superior performance for visual recognition. In this paper, based on the object bank representation, we propose the object-to-class (O2C) distances to model scene images. In particular, four variants of O2C distances are presented, and with the O2C distances, we can represent the images using the object bank by lower-dimensional but more discriminative spaces, called distance spaces, which are spanned by the O2C distances. Due to the explicit computation of O2C distances based on the object bank, the obtained representations can possess more semantic meanings. To combine the discriminant ability of the O2C distances to all scene classes, we further propose to kernalize the distance representation for the final classification. We have conducted extensive experiments on four benchmark data sets, UIUC-Sports, Scene-15, MIT Indoor, and Caltech-101, which demonstrate that the proposed approaches can significantly improve the original object bank approach and achieve the state-of-the-art performance. © 1992-2012 IEEE.


Liu Y.,Shenyang Normal University | Drew M.G.B.,University of Reading | Wang J.,Harbin Engineering University | Zhang M.,Harbin Engineering University
Journal of Magnetism and Magnetic Materials | Year: 2010

A series of powders of M-typed barium hexaferrites doped with Co, Zn and Sn of general formula BaFe12-2xCox/2Znx/2SnxO19 (x=0-2.0) were prepared by the co-precipitation/molten salt method. The structures, particle morphology and magnetic properties of the products were characterized by X-ray powder diffraction, vibrating sample magnetometer and ESEM/EDX. The results show that the crystallinity of the samples decreases with increase in the doping amount x. When x is less than 0.6, it is possible to obtain perfectly crystallized hexagonal BaFe12-2xCox/2Znx/2SnxO19, where the diameters of the particles are around 500 nm. The saturation magnetization of pure barium ferrite BaFe12O19 produced with this method is 71.9 A m2 kg-1 at room temperature and the intrinsic coercivity (Hc) is 367.8 kA m-1. The doped barium hexaferrite powder obtained when x is between 0.3 and 0.4 exhibits high saturation magnetization and a temperature dependence of coercivity close to zero. © 2009 Elsevier B.V. All rights reserved.


Shen F.,Harbin Engineering University | Cheong J.W.,University of New South Wales | Dempster A.G.,University of New South Wales
Measurement Science and Technology | Year: 2015

Relative position awareness is a vital premise for the implementation of emerging intelligent transportation systems, such as collision warning. However, commercial global navigation satellite systems (GNSS) receivers do not satisfy the requirements of these applications. Fortunately, cooperative positioning (CP) techniques, through sharing the GNSS measurements between vehicles, can improve the performance of relative positioning in a vehicular ad hoc network (VANET). In this paper, while assuming there are no obstacles between vehicles, a new enhanced tightly coupled CP technique is presented by adding ultra-wide bandwidth (UWB)-based inter-vehicular range measurements. In the proposed CP method, each vehicle fuses the GPS measurements and the inter-vehicular range measurements. Based on analytical and experimental results, in the full GPS coverage environment, the new tight integration CP method outperforms the INS-aided tight CP method, tight CP method, and DGPS by 11%, 15%, and 24%, respectively; in the GPS outage scenario, the performance improvement achieves 60%, 65%, and 73%, respectively. © 2015 IOP Publishing Ltd.


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