Nanjing, China
Nanjing, China

Nanjing University of Science and Technology or NUST is one of the national key universities under the Ministry of Industry and Information Technology of China. The university was derived from the Institute of Military Engineering of the PLA, which was the highest institution of military technology in China established in 1953. The institute was successively called Artillery Engineering Institute, Engineering Institute of Eastern China, and East China Institute of Technology, and finally to its current name in 1993. It is a science-oriented university located in Xuanwu District in the east suburban area of Nanjing, China. The university places emphasis on both education and research, and is listed in the national 211 Project. The main campus is located in 200 Xiaolingwei, Xuanwu district, Nanjing, Jiangsu Province, China. Wikipedia.

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Lin L.,Nanjing University of Science and Technology | Li Z.,Nanjing University of Science and Technology
Proceedings of 2016 IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference, IMCEC 2016 | Year: 2016

With the decline in air quality, China has frequently appeared foggy and hazy weather. It would have a negligible impact on the detection performance of millimeter wave systems. In this paper, the physical characteristics of fog and haze are discussed in detail. The mechanism of millimeter wave attenuation through fog and haze will be introduced as well. Calculation model of fog scattering and atmospheric absorption attenuation during millimeter wave propagation are established in this paper. Based on the above analysis, it works out the total attenuation consists of the haze scattering and atmospheric absorption, and further analysis the performance of the millimeter-wave systems working at non-atmospheric windows emphatically. The result shows that it has superior anti-reconnaissance performance and anti-jamming performance at non-atmospheric windows. © 2016 IEEE.

Zhang W.,University of Washington | Qi Y.,Nanjing University of Science and Technology | Yan Y.,Chang'an University | Tang J.,Central South University | Wang Y.,University of Washington
Transportation Research Part D: Transport and Environment | Year: 2017

The growth of urban traffic in recent decades has led to environmental problems in terms of increased emissions. In some cities located along waterfronts, multimodal transportation that includes ferry trips plays an important role in public transportation. Compared with roadway traffic, ferry service can often provide shorter routes between given origins and destinations as well as reduce emissions. However, in some areas with high ferry demand, travel delay occurs frequently because of traffic congestion caused by drivers waiting to board the ferry, which can significantly increase travel time and decrease its reliability. In addition, changes in other factors, such as fuel prices, also may influence drivers’ decision making processes in terms of route choice. In this paper, a study focusing on travel time and travel time reliability of ferry service during peak travel periods is performed. Furthermore, as a key result an emission loss model under multimodal conditions is developed that also takes travel cost into account. The analysis of route choice is conducted based on a mixed logit model which is able to handle individual preference. Based upon validation with data from the Seattle area, the proposed model is verified as an efficient way to analyse emission factors in a multimodal transportation environment. © 2017 Elsevier Ltd

Yin H.,CAS Nanjing Institute of Geography and Limnology | Yan X.,Nanjing University of Science and Technology | Gu X.,CAS Nanjing Institute of Geography and Limnology
Water Research | Year: 2017

The cost-effective and geographically available substrates are vital for the design of constructed wetlands (CWs), especially the saturated subsurface flow CWs, which are deemed as an efficient way to remove the inlet-lake phosphorus concentrations. In this study, phosphorus removal of thermally-treated calcium-rich attapulgite (TCAP) with varied particle sizes (0.2–0.5 mm, 0.5–1 mm and 1–2 mm) was assessed using batch and long-term column experiments to evaluate its feasibility as a CWs substrate. The phosphorus-bound mechanism in TCAP was identified in various initial phosphorus concentrations. Batch studies indicated that more than 95% of P can be rapidly (<1 h) removed by TCAP from solution with a concentration of 20 mg P/L, and P sorption can be well fitted by a pseudo-second-order equation. The maximum P sorption capacity of TCAP was in the range of 4.46–5.99 mg P/g, and the availability of Ca2+ concentration might limit the P removal capacity of TCAP at high phosphorus concentrations. Both the P removal rate and capacities decreased with the increase of TCAP particle sizes. Column P removal experiments indicated that hydraulic retention time (HRT) exerts great influence on P removal performance and longer HRTs favor the dissolution of CaO in TCAP, consequently increasing the P removal rate. In a 150-day P removal experiment, TCAP removed an average of 93.1%–95.4% of the influent P with a HRT of eight hours. Both the batch and chemical extraction of the P fraction of TCAP showed that the P removed by TCAP was mainly through formation of Ca phosphate precipitation. However, the species of Ca-P precipitation formed might be varied in different phosphorus concentrations. All results indicated that TCAP can be a suitable substrate when used in CWs, and field experiments should be carried out to test its real P removal performance in the future. © 2017 Elsevier Ltd

Wang Q.,Nanjing University of Science and Technology | Zhu Y.,Nanjing University of Science and Technology | Wang Y.,Nanjing University of Science and Technology
Energy | Year: 2017

This paper investigates the effects of oil shocks on export duration of China using the firm-level dataset of Chinese industrial enterprises over the period 1999–2009. The results show that oil supply shocks and other oil-specific shocks have significantly negative impacts on China's export duration, while aggregate demand shocks have a significantly positive impact on China's export duration in the full sample. The sub-samples analysis shows that the adverse effects of oil supply shocks and aggregate demand shocks on export duration are smaller in energy intensive industries (EII) than in non-energy intensive industries (NEII). All the three oil price shocks have lower adverse effects on China's export duration in the processing firms (PF) than in non-processing firms (NPF). © 2017 Elsevier Ltd

Wang J.,Nanjing University of Science and Technology | Jager T.,Friedrich - Schiller University of Jena
Communications in Mathematical Physics | Year: 2017

We study the phenomenon of mode-locking in the context of quasiperiodically forced non-linear circle maps. As a main result, we show that under certain (Formula presented.)-open condition on the geometry of twist parameter families of such systems, the closure of the union of mode-locking plateaus has positive measure. In particular, this implies the existence of infinitely many mode-locking plateaus (open Arnold tongues). The proof builds on multiscale analysis and parameter exclusion methods in the spirit of Benedicks and Carleson, which were previously developed for quasiperiodic (Formula presented.)-cocycles by Young and Bjerklöv. The methods apply to a variety of examples, including a forced version of the classical Arnold circle map. © 2017 Springer-Verlag Berlin Heidelberg

Xu D.,Nanjing University of Science and Technology | Chen Z.,University of Newcastle | Wang X.,Hefei University of Technology
Automatica | Year: 2017

The authors consider a global robust asymptotic stabilization problem (GRS) for cascaded systems having dynamic uncertainties that are not necessarily input-to-state stable (ISS). Specifically, a recursive Lyapunov design approach is developed by induction on the system relative degree, providing a smoothly globally stabilizing controller. It is applicable to nonlinear cascaded systems having multiple distinct iISS dynamic uncertainties. The proposed design is constructive and leads to an iISS-Lyapunov characterization in a superposition form for the closed-loop system. © 2017 Elsevier Ltd

Huang X.,Nanjing University of Science and Technology
2016 IEEE International Conference on Ubiquitous Wireless Broadband, ICUWB 2016 | Year: 2016

PCM/FM is a kind of system used in telemetry. In order to meet the needs of the future high-speed telemetry program, this paper studies the design of the 10K to 10M rate universal telemetry system. As the digital technology is more stable and flexible than the analog technology, this paper uses the full digital frequency synthesis technology to achieve PCM/FM modulation. In the digital implementation of PCM/FM modulation and demodulation, the software algorithm uses MATLAB language to simulate and verify, and combined with the hardware debugging results to prove that the system meets the requirements. © 2016 IEEE.

Lu J.-Q.,Nanjing University of Science and Technology | Yang J.-P.,Nanjing University of Science and Technology
2016 IEEE International Conference on Ubiquitous Wireless Broadband, ICUWB 2016 | Year: 2016

Based on the Mattis-Bardeen equations, the contour maps for complex conductivity, bulk surface impedance and conductivity quality factor of a classical superconducting material (aluminum) are calculated with the temperature ranging from 0 K to 1.2K (the transition temperature, Tc), and the frequency ranging from 1 GHz to 162 GHz (twice gap frequency). It is shown that the microwave properties of superconducting materials are mainly determined by temperature when the operating frequency is below the gap frequency. Also, it is found that the surface impedance is near a pure reactance in the range [0, 0.25Tc], and the quality factor is more than 108 in the range [0, 0.1Tc]. © 2016 IEEE.

Ma R.,Nanjing University of Science and Technology | Wang L.,Nanjing University of Science and Technology
2016 IEEE International Conference on Ubiquitous Wireless Broadband, ICUWB 2016 | Year: 2016

The speed of vehicles has been making too many breakthroughs, even 20 times of the speed of sound has been achieved. When using high communicating frequencies, it has huge difficulty to acquire spread spectrum (SS) signals with high Doppler shifts for a receiver. This article studied a time domain parallel acquisition method based on FFT, carrier tracking method for PLL-ring with FLL-ring, getting a full set of signal receiving scheme. Theoretical analysis and simulation results show that the algorithm in this article can complete acquisition. © 2016 IEEE.

Zhang X.,Zhongyuan University of Technology | Gong X.,Nanjing University of Science and Technology
Canadian Journal of Chemistry | Year: 2017

High energetic materials tetranitroacetimidic acid (TNAA) and tetranitroacetamide (NTNAA) with positive oxygen balance (OB = 30%) are highly potential replacements for ammonium perchlorate (AP). Tautomerization from TNAA to NTNAA is feasible, reflected by the activation energy of 160.2 ∼ 170.0 kJ/mol. No transition state appears on the C-NO2 bond breaking, which triggers pyrolysis of two compounds. The C-NO2 bond dissociation energies are 116.1 167.2 kJ/mol and 120.4 ∼ 174.6 kJ/mol for TNAA and NTNAA, respectively. The chemical stabilities of TNAA and NTNAA are higher than that of the insensitive explosive 1,1-diamino-2,2-dinitroethylene. TNAA and NTNAA possess lower impact sensitivities (h50 ≥ 77.51 cm) than AP does. Detonation properties of the composite explosives containing TNAA or NTNAA are comparable with that of the composite explosives containing AP. The acceptable stabilities, highly positive OB, environmentally friendly decomposition products, and the comparable ability to improve detonation performance of composite explosives show that TNAA and NTNAA are potential replacements for AP as an oxidizer used in composite explosives.

Zhang T.,Nanjing University of Science and Technology | Fang Z.,Nanjing University of Science and Technology
RSC Advances | Year: 2017

We describe the synthesis and biological evaluation of C-glycosyl chalcone analogues of aspalathin. The DPPH radical scavenging method was used to detect their antioxidant activity and an MTT colorimetric assay was employed to test the anticancer activity against Hep-G2 liver carcinoma cells and MCF-7 human breast carcinoma cells. The antioxidant ability between C-furanosides and C-pyranosides was compared. Compound 3c′ was shown to be the most promising compound with good antioxidant ability and the ability to inhibit Hep-G2 and MCF-7 cells, with IC50 values of 4.9 μM and 19 μM, respectively. © The Royal Society of Chemistry.

Xiang D.,Nanjing University of Science and Technology | Zhu W.,Nanjing University of Science and Technology
RSC Advances | Year: 2017

We performed ab initio molecular dynamics simulations to study the initiation chemical reaction and subsequent decomposition mechanism of a 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX) crystal at 2160 K. It was found that there are three different initial reactions involved in the decomposition of an isolated TEX molecule. The activation energy barriers for the initial decomposition reactions indicate that among the three initial reaction paths, cleavage of the nitrogen-nitro bond is the easiest path to be triggered. The decomposition of the TEX crystal is triggered by the unimolecular C-H bond breaking to form a hydrogen radical. The generated H radicals can prompt other unreacted TEX molecules to decompose. Moreover, there are many multimolecular reactions during the decomposition of the TEX crystal. Overall, after the decomposition of TEX was triggered, some long chains and complicated carbon-rich heterocyclic rings were formed, and then they split to form small fragments. This study may provide useful information to understand the decomposition mechanism of cage explosives and develop new high-energy explosives. © The Royal Society of Chemistry.

Li Z.-L.,Nanjing University of Science and Technology | Jin L.-K.,Nanjing University of Science and Technology | Cai C.,Nanjing University of Science and Technology
Organic and Biomolecular Chemistry | Year: 2017

A nickel-catalyzed product-controllable imidation and amidation of sp3 C-H bonds in substituted toluenes with sulfonamides were developed. Based on the change of the reaction time and atmosphere from N2 to O2, this reaction proceeded in high yields and excellent selectivity under different conditions. Mechanistic details were also described. © The Royal Society of Chemistry.

Zhang L.W.,Shanghai JiaoTong University | Zhang Y.,Nanjing University of Science and Technology | Liew K.M.,City University of Hong Kong
Composites Part B: Engineering | Year: 2017

Graphene sheets have wide application, in which the integration of multiple disparate fields for the realization of expanded functionalities is of great significance. This study investigates the vibration behavior of quadrilateral single-layered graphene sheets (SLGSs) in a magnetic field using classic plate theory and incorporating nonlocal elasticity theory, concerning the small scale effect. The element-free kp-Ritz method is employed to perform the numerical simulation. The efficiency of the proposed numerical tool is verified by published results. The effect of nonlocal parameters, skew angles, magnetic parameters and boundary conditions on the vibration behavior of parallelogram SLGSs is studied. The results show that skew angles and the magnetic field help increase the fundamental frequencies of SLGSs, which indicates the potential application of SLGSs as highly sensitive mass detectors. Moreover, 14 different quadrilateral SLGSs, with different nonlocal parameters and magnetic parameters for different boundary conditions, are simulated. © 2017 Elsevier Ltd

Tao C.,Nanjing University of Science and Technology | Gao J.,San Jose State University
2014 Workshop on Joining AcadeMiA and Industry Contributions to Test Automation and Model-Based Testing, JAMAICA 2014 - Proceedings | Year: 2014

With the rapid advance of mobile computing technology and wireless networking, there is a significant increase of mobile subscriptions. This drives a strong demand on mobile application testing on mobile devices. Since mobile APPs are native to mobile devices, an underlying mobile platform becomes the basic foundation of their test environments. To achieve effective test automation, test solutions must be compatible, deployable, and executable on different mobile platforms, devices, network, and appliance APIs. This paper is written to provide an approach to modeling mobile test environments based on a Mobile Test Environment Semantic Tree (MTEST). Based on this model, the paper discusses test complexity evaluation methods for test environment. Furthermore, some case study results are reported to demonstrate and analyze the proposed testing models. Copyright 2014 ACM.

Chen S.,Tsinghua University | Fan J.,National University of Singapore | Li G.,Tsinghua University | Feng J.,Tsinghua University | And 2 more authors.
Proceedings of the VLDB Endowment | Year: 2015

Influence maximization, whose objective is to select k users (called seeds) from a social network such that the number of users influenced by the seeds (called influence spread) is maximized, has attracted significant attention due to its widespread applications, such as viral marketing and rumor control. However, in real-world social networks, users have their own interests (which can be represented as topics) and are more likely to be influenced by their friends (or friends' friends) with similar topics. We can increase the influence spread by taking into consideration topics. To address this problem, we study topic-aware influence maximization, which, given a topic-aware influence maximization (TIM) query, finds k seeds from a social network such that the topic-aware influence spread of the k seeds is maximized. Our goal is to enable online TIM queries. Since the topic-aware influence maximization problem is NP-hard, we focus on devising effcient algorithms to achieve instant performance while keeping a high influence spread. We utilize a maximum influence arborescence (MIA) model to approximate the computation of influence spread. To effciently find k seeds under the MIA model, we first propose a best-effort algorithm with 1-1/e approximation ratio, which estimates an upper bound of the topic-aware influence of each user and utilizes the bound to prune large numbers of users with small influence. We devise effective techniques to estimate tighter upper bounds. We then propose a faster topic-sample-based algorithm with ε. (1-1/e ) approximation ratio for any ε ε (0; 1], which materializes the influence spread of some topic-distribution samples and utilizes the materialized information to avoid computing the actual influence of users with small in uences. Experimental results show that our methods significantly outperform baseline approaches. © 2015 VLDB Endowment 21508097/15/02.

Lee T.H.,Yeungnam University | Park J.H.,Yeungnam University | Xu S.,Nanjing University of Science and Technology
Automatica | Year: 2017

In this paper, the problem of delay-dependent stability analysis of time-varying delay systems is investigated. Firstly, a new inequality which is the modified version of free-matrix-based integral inequality is derived, and then by aid of this new inequality, two novel lemmas which are relaxed conditions for some matrices in a Lyapunov function are proposed. Based on the lemmas, improved delay-dependent stability criteria which guarantee the asymptotic stability of the system are presented in the form of linear matrix inequality (LMI). Two numerical examples are given to describe the less conservatism of the proposed methods. © 2016 Elsevier Ltd

Xu Z.-Y.,Nanjing University of Science and Technology | Zhao Z.,Nanjing University of Science and Technology
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

A time-frequency pooled angular spectrum capable of suppressing spatial aliasing effectively is studied for a widely spaced microphone array to estimate multi-source directions of arrival (DOA) in a reverberant environment based on diffuse noise model and time-frequency sparsity of acoustic signals. By using constant false-alarm rate (CFAR) detection technique, only the high-valued elements very likely corresponding to the active sources are temporally pooled. As a result, the difference between the true DOA peaks and the false ones are enlarged significantly, which is more important for multi-source detection and localization. Simulation results demonstrate that the proposed method obviously outperforms the existing counterparts in spatial aliasing suppression for widely spaced arrays. © 2016 IEEE.

Wang X.J.,Nanjing University of Science and Technology | Xiao J.J.,Nanjing University of Science and Technology
Structural Chemistry | Year: 2017

Molecular dynamics simulations were carried out to explore a ε-CL-20/HMX (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexazaisowurtzitane/1,3,5,7-tetranitro-1,3,5,7- tetrazacyclooctane) co-crystal-based polymer-bonded explosive (PBX) with HTPB (hydroxyl-terminated polybutadiene). The binding energies, pair correlation functions, and mechanical properties of the PBXs were reported. From the calculated binding energy, it was found that the order of the binding energies per unit surface between the crystalline surface and HTPB is (0 1 0) > (1 0 0) > (0 0 1). The pair correlation function revealed that the H···O and H···N H-bonds exist on the interfaces between the crystalline surfaces and HTPB, and the number of H∙∙∙O hydrogen bonds (H-bonds) atom pairs is ten times more than that of H∙∙∙N H-bonds. Additionally, the calculated mechanical data indicated that the stiffness of the co-crystal/HTPB PBX is weaker and its ductility is better than those of the co-crystal. © 2017 Springer Science+Business Media New York

Liu J.-X.,Nanjing University of Posts and Telecommunications | Sun Q.-S.,Nanjing University of Science and Technology
IET Signal Processing | Year: 2017

Exact compressed sensing (CS) recovery theoretically depends on a large number of random measurements. In this study, the authors present a novel CS measurement technique based on the cellular automata chaos (CAC) model. The proposed method selects original signal thresholding (OST) as its initial seed to realise CS signal coding. The benefits of CS coding with CAC-OST are that: (i) the signal compression ratio of this coding method can be far below the signal sparsity level and (ii) the signal can be recovered perfectly, even with slow CS measurements. This study reports some experiments that demonstrate the excellent performance of CAC-OST in CS coding. © The Institution of Engineering and Technology.

Qin H.,Nanjing University of Science and Technology | Dai Y.,Nanjing University of Science and Technology
Quantum Information Processing | Year: 2017

Through generating the d-dimensional GHZ state in the Z-basis and measuring it in the X-basis, a dynamic quantum secret sharing scheme is proposed. In the proposed scheme, multiple participants can be added or deleted in one update period, and the shared secret does not need to be changed. The participants can be added or deleted by themselves, and the dealer does not need to be online. Compared to the existing schemes, the proposed scheme is more efficient and more practical. © 2017, Springer Science+Business Media New York.

Wang L.,Nanjing University of Science and Technology | Song H.,Nanjing University of Science and Technology | Wang Y.,Anyang University, China
Computers and Industrial Engineering | Year: 2017

This paper investigates the pricing and service decisions of complementary products in a dual-channel supply chain which consists of two manufacturers and one common retailer. One of two manufacturers distributes products through both the direct online channel and the traditional retail channel. Considering the efficacy of different supply chain structures and two types of channel pricing forms, four game models are established. By using the backwards induction and game theory, the corresponding analytical equilibrium solutions are obtained. Finally, numerical examples are presented to compare the effectiveness of optimal results, which gained from the model above and perform a sensitivity analysis of some key parameters, by which obtain some valuable managerial insights. © 2016 Elsevier Ltd

An D.,Nanjing University of Science and Technology | Ye Z.,Nanjing University of Science and Technology
Journal of Dispersion Science and Technology | Year: 2017

A series of glucosyl esters surfactants were synthesized based on glucose molecule by enzymatic catalysis. It could reach the highest esterification yield of 83.4% at the optimal condition, molar ratio of D-glucose and fatty acyl amino acid as 3:2 using 11% (w/w) enzyme catalyst Lipozyme 435 as catalyst in t-butanol at 40°C. The surface activities were studied, such as the critical micelle concentration (CMC), surface tension (γcmc), maximum excess concentration (Γmax), minimum surface area/molecule (Amin), and the adsorption efficiency (pC20); values of these were obtained by surface tension test. The results show that the longer the hydrophobic chain length, the lower the CMC and γcmc. The CMCs of novel glucosyl esters were between 4.4 and 1.5 mM. Further, the micellization physiochemical parameters, including Gibbs free energy of micellization (ΔG), standard enthalpy change (ΔH), and standard entropy change (ΔS) were calculated. It was indicated the micellization of glucosyl esters 9–16 was driven by entropy and deduced at different temperature. © 2017 Taylor & Francis.

Peng G.,Nanjing University of Science and Technology | Zhang Y.-Y.,Nanjing University of Science and Technology | Li Z.-Y.,Tohoku University
Inorganic Chemistry Communications | Year: 2017

Two mononuclear DyIII complexes [Dy(H2TEG)(NO3)3]·[18-crown-6] (H2TEG = triethylene glycol) (1) and [Dy(H2TEG)Cl3]·[18-crown-6] (2) have been prepared using H2TEG as ligands. Magnetic studies revealed that both complexes show field-induced double magnetic relaxation behavior with energy barriers of 28 K and 54 K. Distinct magnetic dynamic properties observed in 1 and 2 are mostly attributed to the dissimilar coordination environments around DyIII centers in these two complexes. © 2017 Elsevier B.V.

Xu Z.-B.,Nanjing University of Science and Technology | Lu G.-P.,Nanjing University of Science and Technology | Cai C.,Nanjing University of Science and Technology
Organic and Biomolecular Chemistry | Year: 2017

An acid-induced protocol for the chemoselective arylthiolations of electron-rich arenes in ionic liquids from sodium arylsulfinates is introduced. The chemistry, in which [Hmim]Br (heaxylmethylimidazolium bromide) is used as both a solvent and a reducer, provides several advantages including odorless and simple operation, inexpensive reagents, recyclable solvents and gram-scale synthesis. © 2017 The Royal Society of Chemistry.

Lin Y.-M.,Nanjing University of Science and Technology | Lu G.-P.,Nanjing University of Science and Technology | Wang R.-K.,Nanjing University of Science and Technology | Yi W.-B.,Nanjing University of Science and Technology
Organic Letters | Year: 2017

A radical-mediated approach has been introduced for the C-S bond activation of arylalkenyl sulfides. The protocol provides an efficient approach for the generation of various alkenes including alkenyl silanes, sulfones, phosphine oxides, and nitroolefins. In most cases, these radical substitutions are performed under metal-free conditions with stereospecificity. © 2017 American Chemical Society.

Gu X.,Nanjing University of Science and Technology | Fang Z.,Nanjing University of Science and Technology
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2017

In this paper, two novel easily available probes based on rhodamine B and β-C-glycoside were synthesized and characterized by 1H NMR, 13C NMR and elemental analysis. Sensor 1 exhibited very high sensitivity and selectivity toward Hg2 + over other metal ions, due to the opening of the spiro ring in thiooxorhodamine B caused by Hg2 + through desulfurization. The binding analysis using Job's plot suggested 1:1 stoichiometry for the complexes formed for Hg2 +. The fluorescent probe is pH independent in medium condition and common interferent ions do not show any interference with the Hg2 + determination. It is anticipated that 1 could be a good candidate probe and has potential application for Hg2 + determination. © 2016 Elsevier B.V.

Gao X.,Nanjing University of Science and Technology | Feng W.,Nanjing University of Science and Technology | Che W.,Nanjing University of Science and Technology
IEEE Microwave and Wireless Components Letters | Year: 2017

Two novel high-selectivity wideband balanced filters using symmetrical/asymmetrical coupled lines with open/shorted stubs are proposed in this letter. Multiple transmission zeros are achieved to obtain sharp rejection and good out-of-band suppression for the differential mode, in which fixed transmission zeros can be realized by half-wavelength open stubs and adjustable transmission zeros can be realized by loaded open/shorted coupled lines. In addition, all the transmission zeros can be allocated to suppress the common mode from 0 GHz to 3f0 (f0 is the center frequency of the passband). Two balanced filters with 3-dB fractional bandwidths of 22% and 21% are, respectively, designed and fabricated. © 2001-2012 IEEE.

Guo X.,Nanjing University of Science and Technology | Zhu L.,Macau University of Science and Technology | Wu W.,Nanjing University of Science and Technology
IEEE Microwave and Wireless Components Letters | Year: 2017

This letter presents an optimized design of differential moderate-band bandpass filter (BPF) with intrinsic common-mode rejection on three half-wavelength slotline resonators. The slotline resonator element's unloaded $Q$ -factor is highly enhanced by using a long coupling length. Thus, it can be utilized to construct a low insertion loss differential moderate-band BPF. © 2017 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.

Bao H.,Nanjing University of Science and Technology | Chen R.,Nanjing University of Science and Technology
IEEE Transactions on Antennas and Propagation | Year: 2017

A flexible and universal domain decomposition parallel scheme is proposed for the unconditionally stable finite-difference time-domain (FDTD) method. The leapfrog alternating direction implicit FDTD (ADI-FDTD) method is employed to eliminate the restriction of the Courant-Friedrichs-Lewy stability condition. The proposed domain decomposition parallel implementation of the leapfrog ADI-FDTD method is more flexible with process allocation and requires fewer data communications. A buffer region is introduced to decouple the interactions between neighboring subdomains at each time step. Electromagnetic simulations are presented to demonstrate the applicability, accuracy, and efficiency of the proposed method. © 1963-2012 IEEE.

Zhou L.,Nanjing University of Science and Technology | Yu Y.,Nanjing University of Science and Technology
Applied Ocean Research | Year: 2017

To further understand the gas-curtain generation characteristics during the launching process of the underwater guns, a simulated gas-injector with multiple nozzles is designed and the expansion process of these multiple combustion-gas jets is experimentally captured. Experiment results indicate that, with turbulent mixing between the gas jets and the liquid medium, the gas curtain is generated in the observation chamber. Based on the experiment, a three dimensional unsteady model is established to simulate the expansion process of the multiple jets. Numerical result shows, with the injection of the gas jets, pressure declines in the Taylor cavity along the axial direction at the beginning. During the expansion process, the multiple jets contact and interact with each other, and pressure rises in the mixing area. After merging, backflow vortexes interact and converge, and the vortexes move along the axial direction with the expansion of the combustion gas jets. © 2017 Elsevier Ltd

Pan X.,Nanjing University of Science and Technology | Weng C.,Nanjing University of Science and Technology
Nanjing Li Gong Daxue Xuebao/Journal of Nanjing University of Science and Technology | Year: 2017

To explore the working characteristics of small-scale pulse detonation engine(SPDE), a series of experiments and numerical simulations are carried out on SPDE.A gas-liquid small-scale pulse detonation rocket engine is designed with 30 mm inner diameter and a total length of 900 mm. The characteristics of pressure wave in detonation tube at different ignition frequencies are studied by using gasoline as fuel. Multi-cycle detonation experiments show that SPDE can work stably and continuously under the frequency range of 10~40 Hz, and the average pressure of detonation wave is between 2~3 MPa; with the increase of frequency, the peak pressure and the average pressure are reduced. Two-dimensional CE/SE method is used to simulate the propagation characteristics of detonation wave in gas-liquid two-phase SPDE, and the calculation results are in good agreement with the experimental results. The research results are significant to the study of SPDE atomization, mixing and the realization of high frequency SPDE. © 2017, Editorial Department of Journal of Nanjing University of Science and Technology. All right reserved.

Cao Y.-F.,Nanjing University of Science and Technology | Xu C.,Nanjing University of Science and Technology
Binggong Xuebao/Acta Armamentarii | Year: 2017

Muzzle velocity degradation prediction of machine gun is a complicated non-linear problem. Generalized regression neural network (GRNN) has been widely used in the modeling of the non-linear problems, but GRNN has rarely been used to predict the muzzle velocity degradation of machine gun. Since the smoothing factor of GRNN obviously affects the prediction performance of neural network, the fruit fly optimization algorithm is used to automatically select the parameters of GRNN. A method to model a muzzle velocity degradation based on general regression neural network with fruit fly optimization algorithm (FOAGRNN) is proposed. A prediction model is established based on the experimental data of muzzle velocity degradation, in which the muzzle velocity degradation is taken as characteristic quantity. The predicted results are basically consistent with the experimental results. The research result shows that FOAGRNN model outperforms GRNN model with default parameter and BPNN prediction model in the prediction of muzzle velocity degradation. © 2017, Editorial Board of Acta Armamentarii. All right reserved.

Lin Q.-H.,Nanjing University of Science and Technology | Li B.-M.,Nanjing University of Science and Technology
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2017

In order to investigate the thermal generation mechanisms and temperature distribution characteristics of electromagnetic railgun, a 3D transient electromagnetic field and thermal field coupling model was developed. The finite element method was used to simulate the temporal and spatial evolution of temperature distribution in barrel and projectile, the cooling process of barrel was also calculated. The results of numerical simulation indicated that the melting-wave effect generated on the armature, the temperature rose rapidly in the rails nearing breech, the rail played a major role in heat conduction at the initial stage after launch. This model built the relationships of the barrel configuration, material properties, electrical current and temperature, indicated the rails adjacent to breech was the critical areas for thermal management, and provided the theoretical basis for the thermal design of railgun launchers. © 2017, Science Press. All right reserved.

Xu Q.,Nanjing University of Science and Technology | He W.-D.,Nanjing University of Science and Technology
Hanneng Cailiao/Chinese Journal of Energetic Materials | Year: 2017

Zhao Q.-Q.,Nanjing University of Science and Technology | Hou B.-L.,Nanjing University of Science and Technology
Binggong Xuebao/Acta Armamentarii | Year: 2017

Shell transfer arm is a complicated mechatronic and hydraulic integrated system of howitzer with multi-parameters. During the modeling process, some parameters are hard or unable to be measured but have significant effect on the performance of shell transfer arm, which can only be achieved by identification. For identifying the parameters of shell transfer arm, the dynamic and control models are built in Simulink, and the uncertainty parameters are described by interval number. The identification problem of interval uncertainty parameters is transformed into a certainty optimization problem via order relation of interval number transformation model. The similarity of angular velocity of shell transfer arm is set as the optimization objective function, and three parameters are identified by differential evolution (DE) method. The proposed method is verified by simulated and test data. The identification results of simulated data show that the identification accuracy satisfies the requirement, and the identification results of test data show that the proposed method is feasible and effective. © 2017, Editorial Board of Acta Armamentarii. All right reserved.

Xu M.,Nanjing University of Science and Technology | Liu D.,Nanjing University of Science and Technology
Journal of Energetic Materials | Year: 2017

A new type of composite explosive used in a permissible detonator for coal mining has been manufactured through a two-phase granulation process. The new composite explosive (NCE) contains 79–88 wt% RDX, 3–5 wt% polymer binder, 1.5–2.5 wt% insensitive agent, 6–14 wt% sodium aluminum silicate (SAS), and 1–2 wt% polyvinyl alcohol (PVA). Firstly, a water suspension granulation method was utilized to produce spherical explosive molding powder. Then, the molding powder was coated with a flame inhibitor by a spraying granulation technique. Comparatively, the molding powder provided in this work outperforms the powder manufactured from other processing in terms of fluidity, particle size distribution, flame inhibitor coating quality, and accumulation of static electricity as a result of the chemical composition and the unique granulation process. This study offers a new type of detonating explosive with improved safety and initiating ability for mining industries, and it may also provide a novel strategy for processing other types of energetic materials. © 2017 Taylor & Francis Group, LLC

Chen C.,Nanjing University of Science and Technology | Wang Y.,Nanjing University of Science and Technology
Physica A: Statistical Mechanics and its Applications | Year: 2017

The multifractality in stock returns have been investigated extensively. However, whether the autocorrelations in portfolio returns are multifractal have not been considered in the literature. In this paper, we detect multifractal behavior of returns of portfolios constructed based on two popular trading rules, size and book-to-market (BM) ratio. Using the multifractal detrended fluctuation analysis, we find that the portfolio returns are significantly multifractal and the multifractality is mainly attributed to long-range dependence. We also investigate the multifractal cross-correlation between portfolio return and market average return using the detrended cross-correlation analysis. Our results show that the cross-correlations of small fluctuations are persistent, while those of large fluctuations are anti-persistent. © 2016 Elsevier B.V.

Filimonov S.N.,Tomsk State University | Liu W.,Nanjing University of Science and Technology | Tkatchenko A.,University of Luxembourg
Journal of Physical Chemistry Letters | Year: 2017

The design of novel elementary surface processes is important for applications in catalysis, single-molecule junctions, molecular sensors, switches, and surface-mounted molecular machines. Here we demonstrate by van der Waals inclusive density functional theory calculations that a small and relatively simple heteroaromatic compound s-triazine (C3H3N3) unexpectedly possesses five metastable states when adsorbed on the Pt(111) surface. This diversity of the adsorption states stems from an interplay between versatile molecule/surface chemical bonding and van der Waals interactions and from “softening” of the aromatic ring by nitrogen substitution, which makes folding of the aromatic ring energetically much less demanding as compared to benzene. The intricate seesaw-like surface dynamics and tunable electronic structure of s-triazine show promise for applications in molecular sensors and switches. The broad implications of our findings are demonstrated for triazine- and pyrimidine-based heteroaromatic compounds and other metal surfaces. © 2017 American Chemical Society.

Dai X.,Nanjing University of Science and Technology | Dai X.,PLA University of Science and Technology
Materials Research Express | Year: 2017

Nano ZnO enhanced 3D porous reduced graphene oxide (RGO) with superior electromagnetic interferece (EMI) shielding efficiency (SE) was fabricated through a UV enhanced hydrothermal process. In this study, a composite with 10 wt% of 3D-RGO/ZnO was tested in a broadband frequency range from 2 to 18 GHz. Under the whole test conditions, the ratio of SEA/SET is higher than 50% and the maximum value can reach to 94%, indicating the shielding mechanism mainly attributes to absorption. The EMI SE showed that the thinnest thicknesses to shield different frequency range are 0.7 mm for 10 dB, 1.6 mm for 20 dB and 3.7 mm for 30 dB, which suggests 3D-RGO/ZnO could meet the requirement of new generate EMI shielding material. © 2017 IOP Publishing Ltd.

Li B.,Nanjing University of Science and Technology | Zhu Y.,Nanjing University of Science and Technology
Engineering Optimization | Year: 2017

It is well known that the optimal control of a linear quadratic model is characterized by the solution of a Riccati differential equation. In many cases, the corresponding Riccati differential equation cannot be solved exactly such that the optimal feedback control may be a complex time-oriented function. In this article, a parametric optimal control problem of an uncertain linear quadratic model under an optimistic value criterion is considered for simplifying the expression of optimal control. Based on the equation of optimality for the uncertain optimal control problem, an approximation method is presented to solve it. As an application, a two-spool turbofan engine optimal control problem is given to show the utility of the proposed model and the efficiency of the presented approximation method. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Shao Z.,Nanjing University of Science and Technology | Xiang Z.,Nanjing University of Science and Technology
International Journal of Systems Science | Year: 2017

This paper is concerned with the design of a high-order repetitive control (RC) law for a class of discrete-time linear switched systems with repetition-varying reference trajectories. First, a high-order RC law, which embeds the characteristic of known variation of the reference trajectories, is proposed to the system, and a two-dimensional (2D) model is presented to describe the control and learning actions of the repetitive control system by using the lifting technique. By choosing appropriate multiple Lyapunov–Krasovskii functions, sufficient conditions for asymptotic stability of the 2D system are derived in the form of a set of linear matrix inequalities. Finally, an example is given to illustrate the effectiveness of the proposed results. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Zou W.,Nanjing University of Science and Technology | Xiang Z.,Nanjing University of Science and Technology
International Journal of Systems Science | Year: 2017

In this paper, the event-triggered distributed containment control of heterogeneous linear multi-agent systems in the output regulation framework is studied. The leaders are treated as exosystems and the containment control problem will be converted into an output regulation problem. An event-triggered protocol is then designed for each follower by the output information of neighbours. It is proved that the followers can asymptotically converge to the dynamic convex hull spanned by multiple leaders under the designed protocol and triggered strategy. Furthermore, it is shown that the proposed protocol and triggered condition can exclude Zeno behaviour, so the feasibility of the control strategy is verified. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed protocol. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Xu B.,Nanjing University of Science and Technology | Dou L.,Nanjing University of Science and Technology
CGNCC 2016 - 2016 IEEE Chinese Guidance, Navigation and Control Conference | Year: 2016

This paper presents a vector tracking loop (VTL)-based carrier tracking algorithm assisted by desired trajectory of vehicles during short signal outages. The VTL-based carrier tracking algorithm is first derived. The desired trajectory of vehicles is then introduced to assist the VTL, ensuring that the carrier numerically controlled oscillator (NCO) keeps working during signal outages. The performance improvement of the proposed algorithm is verified in two different scenarios. It is shown that the VTL assisted by desired trajectory has higher frequency precision than that with no assistance. Besides, the proposed method can maintain the navigation solving and restrain the frequency error from increasing. © 2016 IEEE.

An Y.-C.,Nanjing University of Science and Technology | Suo H.-M.,Guizhou University
Advances in Mathematical Physics | Year: 2017

This paper studies the following system of degenerate equations - d i v p x δ u + q x u = α u + β v + g 1 x, v + h 1 x, x ϵ Ω, - d i v (p (x) δ v) + q (x) v = β u + α v + g 2 (x, u) + h 2 (x), x ϵ Ω, ∂ u / ∂ = ∂ v / ∂ = 0, x ϵ ∂ Ω. Here Ω ⊂ R n is a bounded C 2 domain, and is the exterior normal vector on ∂ Ω. The coefficient function p may vanish in Ω , q ϵ L r (Ω) with r > n s / (2 s - n), s > n / 2. We show that the eigenvalues of the operator - d i v (p (x) δ u) + q (x) u are discrete. Secondly, when the linear part is near resonance, we prove the existence of at least two different solutions for the above degenerate system, under suitable conditions on h 1, h 2, g 1, and g 2. © 2017 Yu-Cheng An and Hong-Min Suo.

Ban T.,Nanjing University of Science and Technology | Junior G.G.S.,Telecom ParisTech
Journal of Electrical and Computer Engineering | Year: 2017

Hardware redundancy at different levels of design is a common fault mitigation technique, which is well known for its efficiency to the detriment of area overhead. In order to reduce this drawback, several fault-tolerant techniques have been proposed in literature to find a good trade-off. In this paper, critical constituent gates in math circuits are detected and graded based on the impact of an error in the output of a circuit. These critical gates should be hardened first under the area constraint of design criteria. Indeed, output bits considered crucial to a system receive higher priorities to be protected, reducing the occurrence of critical errors. The 74283 fast adder is used as an example to illustrate the feasibility and efficiency of the proposed approach. © 2017 Tian Ban and Gutemberg G. S. Junior.

Xia G.,Nanjing University of Science and Technology | Sun H.,Nanjing University of Science and Technology | Niu X.,Nanjing Chenguang Group Corporation | Zhang G.,Nanjing University of Science and Technology | Feng L.,Nanjing University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2017

Human motion capture data, which are used to animate animation characters, have been widely used in many areas. To satisfy the high-precision requirement, human motion data are captured with a high frequency (120 frames/s) by a high-precision capture system. However, the high frequency and nonlinear structure make the storage, retrieval, and browsing of motion data challenging problems, which can be solved by keyframe extraction. Current keyframe extraction methods do not properly model two important characteristics of motion data, i.e., sparseness and Riemannian manifold structure. Therefore, we propose a new model called joint kernel sparse representation (SR), which is in marked contrast to all current keyframe extraction methods for motion data and can simultaneously model the sparseness and the Riemannian manifold structure. The proposed model completes the SR in a kernel-induced space with a geodesic exponential kernel, whereas the traditional SR cannot model the nonlinear structure of motion data in the Euclidean space. Meanwhile, because of several important modifications to traditional SR, our model can also exploit the relations between joints and solve two problems, i.e., the unreasonable distribution and redundancy of extracted keyframes, which current methods do not solve. Extensive experiments demonstrate the effectiveness of the proposed method. © 1982-2012 IEEE.

Xu L.,Nanjing University of Science and Technology | Nallanathan A.,King's College London | Song X.,Nanjing University of Aeronautics and Astronautics
IEEE Transactions on Wireless Communications | Year: 2017

In this paper, a joint video scheduling, subchannel assignment, and power allocation problem in cognitive heterogeneous networks are modeled as a mixed integer non-linear programming (MINLP), which maximizes the minimum video transmission quality among different secondary mobile terminals (MTs) subject to the total available energy at each secondary, the total interference power at each primary base station, the total available capacity at each radio interface of each secondary MTs, and the video sequence encoding characteristic. In order to solve it, we decompose the original MINLP as joint subchannel and power allocation problem and video packet scheduling problem. Then, we model the joint subchannel and power allocation problem as a max-min fractional programming, and transform it as a convex optimization problem. Finally, we utilize dual decomposition method to design a joint subchannel and power allocation algorithm, and propose a video packet scheduling scheme based on auction theory to maximize the video quality for each secondary MT. Simulation results demonstrate that the proposed framework not only improves the video transmission quality significantly, but also guarantees the fairness among different secondary MTs. © 2017 IEEE.

Xu J.,Northwestern Polytechnical University | Xu J.,Nanjing University of Science and Technology | Xu J.,Nanjing Southeast University | Zhu Y.,Northwestern Polytechnical University
IEEE Transactions on Industrial Electronics | Year: 2017

In this paper, a new technique using two p-i-n diodes to switch between two channels of a tunable diplexer with constant return loss is proposed to design a tunable bandpass filter (BPF) with wide frequency tuning range (FTR). The used third-order tunable diplexer with two independently tuned channels consists of one common varactor-tuned lumped-element dual-resonance resonator and two varactor-tuned LC resonators. The ports of its two channels are connected by a single-pole double-throw switch, so that one port of the tunable BPF is constituted. And its common port serves as the other port of the tunable BPF. In the switched tunable diplexer design, its direct current (dc) bias voltages are also appropriately selected to improve the in-band and out-of-band performances of the tunable BPF. As examples, a third-order tunable diplexer with constant return loss of 15 dB is first designed. The measured results show that the 3 dB cutoff frequency of its lower channel can be tuned from 0.5 to 1.02 GHz, while the 3 dB cutoff frequency of its upper channel can be tuned from 1.01 to 1.78 GHz. Then, a tunable BPF is designed, and its 3 dB cutoff frequency covers from 0.485 to 1.82 GHz. The proposed tunable BPF exhibits good return loss, wide FTR, and compact size. © 2016 IEEE.

Shao Z.,Nanjing University of Science and Technology | Xiang Z.,Nanjing University of Science and Technology
IET Control Theory and Applications | Year: 2017

This study is concerned with the iterative learning controller design for a class of non-linear switched discrete-time repetitive systems. First, the definitions of exponential stability and average dwell time in iterative learning control (ILC) systems are introduced, and sufficient conditions for exponential stability of non-linear switched discrete-time ILC systems are established by using the methods of common two-dimensional (2D) Lyapunov function and multiple 2D Lyapunov functions, respectively. Then, the proposed results are used to design the iterative learning controller. Finally, an example is given to illustrate the effectiveness of the proposed results. © The Institution of Engineering and Technology 2017.

Chen T.,Nanjing University of Science and Technology | Cai C.,Nanjing University of Science and Technology
New Journal of Chemistry | Year: 2017

An efficient approach for the synthesis of N-substituted 3-oxoisoindoline-1-difluoroalkyl derivatives via a one-pot cascade reaction has been developed. The reaction proceeded smoothly in the presence of In(OTf)3 and afforded a broad scope of isoindolinones with moderate to good yields. Moreover, the reaction could be run on a gram-scale with comparable yield. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Zhou L.,Nanjing University of Science and Technology | Yu Y.,Nanjing University of Science and Technology
Experimental Thermal and Fluid Science | Year: 2017

To further understand the mechanism of new submerged water piercing gun launcher, the simulation device of an imitated projectile is designed with using multi combustion gas jets to drain off the water in gun tube. The expansion characteristic of multi gas jets and generation mechanism of the gas-curtain in the liquid medium are experimental observed by a high speed camera. The experiment shows that, with the mixing process between the multi combustion gas jets and the liquid medium, the gas-curtain is generated, which provides a gas path for the projectile motion. On the base of experimental observation result, the influences of injection pressure and sprayer structure on projectile motion are discussed. Experiment result indicates: increasing injection pressure, both axial expansion velocities of gas-curtain and projectile moving speed increase; magnifying the center nozzle cannot enhance the drainage performance of the gas-curtain and will restrain projectile motion in the later stage; with enlarging the oblique plane nozzles, the axial velocity of gas-curtain tend to rise after converging and projectile kinematic performance is also improved. © 2017 Elsevier Inc.

Zhang J.,University of Dayton | Zhang J.,Nanjing University of Science and Technology | Hirakawa K.,University of Dayton
IEEE Transactions on Image Processing | Year: 2017

This paper describes a study aimed at comparing the real image sensor noise distribution to the models of noise often assumed in image denoising designs. A quantile analysis in pixel, wavelet transform, and variance stabilization domains reveal that the tails of Poisson, signal-dependent Gaussian, and Poisson-Gaussian models are too short to capture real sensor noise behavior. A new Poisson mixture noise model is proposed to correct the mismatch of tail behavior. Based on the fact that noise model mismatch results in image denoising that undersmoothes real sensor data, we propose a mixture of Poisson denoising method to remove the denoising artifacts without affecting image details, such as edge and textures. Experiments with real sensor data verify that denoising for real image sensor data is indeed improved by this new technique. © 1992-2012 IEEE.

Hu J.,CAS Shenyang Institute of Metal Research | Shi Y.N.,CAS Shenyang Institute of Metal Research | Sauvage X.,INSA Rouen | Sha G.,Nanjing University of Science and Technology | And 2 more authors.
Science | Year: 2017

Conventional metals become harder with decreasing grain sizes, following the classical Hall-Petch relationship. However, this relationship fails and softening occurs at some grain sizes in the nanometer regime for some alloys. In this study, we discovered that plastic deformation mechanism of extremely fine nanograined metals and their hardness are adjustable through tailoring grain boundary (GB) stability. The electrodeposited nanograined nickel-molybdenum (Ni-Mo) samples become softened for grain sizes below 10 nanometers because of GB-mediated processes. With GB stabilization through relaxation and Mo segregation, ultrahigh hardness is achieved in the nanograined samples with a plastic deformation mechanism dominated by generation of extended partial dislocations. Grain boundary stability provides an alternative dimension, in addition to grain size, for producing novel nanograined metals with extraordinary properties.

Sun H.,Nanjing University of Science and Technology | Su C.-L.,University of Chicago | Chen X.,Hong Kong Polytechnic University
Mathematical Programming | Year: 2017

Utility-based choice models are often used to determine a consumer’s purchase decision among a list of available products; to provide an estimate of product demands; and, when data on purchase decisions or market shares are available, to infer consumers’ preferences over observed product characteristics. These models also serve as a building block in modeling firms’ pricing and assortment optimization problems. We consider a firm’s multiproduct pricing problem, in which product demands are determined by a pure characteristics model. A sample average approximation (SAA) method is used to approximate the expected market share of products and the firm profit. We propose an SAA-regularized method for the multiproduct price optimization problem. We present convergence analysis and numerical examples to show the efficiency and the effectiveness of the proposed method. © 2017 Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society

Jiao T.,Nanjing University of Science and Technology | Zheng W.X.,University of Western Sydney
2016 IEEE 55th Conference on Decision and Control, CDC 2016 | Year: 2016

This paper is concerned with analyzing noise-to-state stability of a class of nonlinear systems with random disturbances and impulses. It is assumed that the random noises have finite second-order moments and the random impulses have impulse ranges driven by a sequence of random variables. The Lyapunov approach is first utilized to establish the criteria on global existence and stability of solutions for the considered random nonlinear impulsive systems. Then the average impulsive interval approach is applied to develop sufficient conditions on noise-to-state stability of random nonlinear impulsive systems. A numerical example is presented to show the efficiency of the proposed theoretical results. © 2016 IEEE.

Tang J.,Nanjing University of Science and Technology | Li Z.,Nanjing University of Science and Technology | Zhu X.,Nanjing University of Science and Technology
Pattern Recognition | Year: 2017

Hashing has been widely utilized for Approximate Nearest Neighbor (ANN) search due to its fast retrieval speed and low storage cost. In this work, we propose a novel supervised hashing method for scalable face image retrieval, i.e., Deep Hashing based on Classification and Quantization errors (DHCQ), by simultaneously learning feature representations of images, hash codes and classifiers. The supervised information and the deep architecture are collaboratively explored. Specifically, a deep convolutional network is introduced to learn discriminative feature representations, which are directly used to generate hash codes and predict labels of images. The quantization errors and the prediction errors jointly guide the learning of the deep network. They are highly interrelated and promoted each other. It is worth noting that the proposed method is a general hashing method and can be applied to the general image retrieval task. Extensive experiments on two face image datasets and one general image dataset demonstrate the effectiveness of the proposed method compared with several state-of-the-art hashing methods. © 2017 Elsevier Ltd.

Liao J.,Nanjing University of Science and Technology | Gao W.,Nanjing University of Science and Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

The kidneys are essential regulatory organs whose main function is to regulate the balance of electrolytes in the blood, along with maintaining pH homeostasis. The study of the microscopic structure of the kidney will help identify kidney diseases associated with specific renal histology change. Spectrally encoded microscopy (SEM) is a new reflectance microscopic imaging technique in which a grating is used to illuminate different positions along a line on the sample with different wavelengths, reducing the size of system and imaging time. In this paper, a SEM device is described which is based on a super luminescent diode source and a home-built spectrometer. The lateral resolution was measured by imaging the USAF resolution target. The axial response curve was obtained as a reflect mirror was scanned through the focal plane axially. In order to test the feasibility of using SEM for depth-section imaging of an excised swine kidney tissue, the images of the samples were acquired by scanning the sample at 10 μm per step along the depth direction. Architectural features of the kidney tissue could be clearly visualized in the SEM images, including glomeruli and blood vessels. Results from this study suggest that SEM may be useful for locating regions with probabilities of kidney disease or cancer. © 2016 SPIE.

Wang J.,Nanjing University of Science and Technology | Ke J.,Nanjing University of Science and Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

LIDAR three-dimensional imaging technology have been used in many fields, such as military detection. However, LIDAR require extremely fast data acquisition speed. This makes the manufacture of detector array for LIDAR system is very difficult. To solve this problem, we consider using compress sensing which can greatly decrease the data acquisition and relax the requirement of a detection device. To use the compressive sensing idea, a spatial light modulator will be used to modulate the pulsed light source. Then a photodetector is used to receive the reflected light. A convex optimization problem is solved to reconstruct the 2D depth map of the object. To improve the resolution in transversal direction, we use multiframe image restoration technology. For each 2D piecewise-planar scene, we move the SLM half-pixel each time. Then the position where the modulated light illuminates will changed accordingly. We repeat moving the SLM to four different directions. Then we can get four low-resolution depth maps with different details of the same plane scene. If we use all of the measurements obtained by the subpixel movements, we can reconstruct a high-resolution depth map of the sense. A linear minimum-mean-square error algorithm is used for the reconstruction. By combining compress sensing and multiframe image restoration technology, we reduce the burden on data analyze and improve the efficiency of detection. More importantly, we obtain high-resolution depth maps of a 3D scene. © 2016 SPIE.

Wan H.,Nanjing University of Science and Technology | Peng C.,Nanjing University of Science and Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

With the development of information technology, two-dimensional code is more and more widely used. In the technology of two-dimensional code recognition, the noise reduction of the two-dimensional code image is very important. Wavelet transform is applied to the noise reduction of two-dimensional code, and the corresponding Matlab experiment and simulation are made. The results show that the wavelet transform is simple and fast in the noise reduction of two-dimensional code. And it can commendably protect the details of the two-dimensional code image. © 2017 SPIE.

Shao Z.,Nanjing University of Science and Technology | Xiang Z.,Nanjing University of Science and Technology
Circuits, Systems, and Signal Processing | Year: 2017

This paper is concerned with the design of an iterative learning control (ILC) law, which is developed to improve the tracking performance of a class of switched repetitive systems with time-varying delay. Firstly, the ILC scheme is introduced and a two-dimensional (2D) switched model is proposed to describe the switched repetitive system. Secondly, sufficient conditions for the exponential stability with l2-gain performance of the 2D switched system are derived by choosing a Lyapunov–Krasovskii functional. The ILC gains are then obtained by solving a set of linear matrix inequalities. Finally, a numerical example is given to illustrate the effectiveness of the proposed results. © 2016, Springer Science+Business Media New York.

Hu Z.,Nanjing University of Science and Technology | Yu Y.,Nanjing University of Science and Technology
Acta Mechanica Sinica/Lixue Xuebao | Year: 2017

To explore further the launch mechanism of the new underwater launching technology proposed in this paper, the expansion characteristics of four wall combustion-gas jets in confined liquid space must be studied firstly. The experimental device is designed, and the high-speed digital photographic system is adopted to obtain the expansion sequence processes of Taylor cavities formed by the four wall jets. Meanwhile, the influence of the injection pressure on the axial expansion property of the four wall jets is discussed. Based on the experiments, a three-dimensional unsteady mathematical model is established to simulate the turbulent flow process of the four wall jets expanding in liquid, and the temporal and spatial distribution laws of phase, pressure, temperature, and velocity and the evolution rules of vortices are illustrated in detail. Results show that, accompanied by the jets expanding downstream, the four wall combustion-gas jets get close to each other and achieve convergence eventually under induction of the interference effect between multiple jets. Meanwhile, the heads of the Taylor cavities separate from the observation chamber wall and offset to the central axis of the observation chamber with time going on. The numerical simulation results of the four wall combustion-gas jets coincide well with the experimental data. © 2017 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg

Wang J.-M.,Nanjing University of Science and Technology | Du Y.,Nanjing University of Science and Technology
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2017

2, 6-Diamino-pyrazine-1-oxide(DAPO) was synthesized by two-step reactions of nitrosylation and cyclization, using iminodiacetonitrile as starting material. The total yield of DAPO was 66.6%. Its structure was characterized by 1H NMR, IR and MS. The effects of catalyst, dosage of sodium hydroxide and initial temperature etc factors for cyclization reaction on the total yield of DAPO were investigated. Triethylamine used in traditional synthesis method was replaced by sodium hydroxide as the catalyst. The optimum process conditions of preparing DAPO via cyclization reaction were determined as∶ONN(CH2CN)2∶NH2OH·HCl∶NaOH=1.0∶0.6∶1.0 (mass ratio), the initial temperature was 5-10℃, the reaction time was 30min, then, the reaction temperature was 20℃, the reaction time was 2h. The results show that compared with the method of triethylamine as catalyst, the yield of synthesizing DAPO by cyclization reaction is significantly increased from 57.0% to 78.7% with sodium hydroxide as catalyst. According to the synthetic process of DAPO, the cyclization mechanism of DAPO is proposed: nucleophilic addition occurs between hydroxylamine and N-nitrosobis(cyanomethyl)amine, generating the condensation product of N-nitroso-bis(cyanomethyl)amine, this compound cyclizes with hydroxylamine under the effect of alkali, and the final product DAPO is obtained. © 2017, Editorial Board of Journal of Explosives & Propellants. All right reserved.

Liu Y.,Nanjing University of Science and Technology | Liu Y.,U.S. National Center for Atmospheric Research | Yang T.,Nanjing University of Science and Technology
Communications in Computational Physics | Year: 2017

In order to study the local refinement issue of the horizontal resolution for a global model with Spherical Centroidal Voronoi Tessellations (SCVTs), the SCVTs are set to 10242 cells and 40962 cells respectively using the density function. The ratio between the grid resolutions in the high and low resolution regions (hereafter RHL) is set to 1:2, 1:3 and 1:4 for 10242 cells and 40962 cells, and the width of the grid transition zone (for simplicity, WTZ) is set to 18° and 9° to investigate their impacts on the model simulation. The ideal test cases, i.e. the cosine bell and global steady-state nonlinear zonal geostrophic flow, are carried out with the above settings. Simulation results showthat the larger the RHL is, the larger the resulting error is. It is obvious that the 1:4 ratio gives rise to much larger errors than the 1:2 or 1:3 ratio; the errors resulting from the WTZ is much smaller than that from the RHL. No significant wave distortion or reflected waves are found when the fluctuation passes through the refinement region, and the error is significantly small in the refinement region. Therefore,when designing a local refinement scheme in the global model with SCVT, the RHL should be less than 1:4, i.e., the error is acceptable when the RHL is 1:2 or 1:3. © 2017 Global-Science Press.

Xu X.-B.,Nanjing University of Science and Technology | Zhang H.,Nanjing University of Science and Technology
Guangzi Xuebao/Acta Photonica Sinica | Year: 2017

Pulse laser fuze of conventional ammunition cannot accurately obtain the azimuth information of target. Therefore, the circumferential azimuth detection scheme of single beam laser fuze was designed based on magnetic-electric detection. The magnetic-electric detection system was modeled; a cylindrical permanent magnet rotating magnetic field model was established. The analytic expression of magnetic position which is measured by magneto resistive sensor was deduced. According to the analytical expression of the magnetic signal, rising along the cycle threshold detection method was put forward. The high precision azimuth resolution was achieved by using the method of combining FPGA with TDC-GP21 to measure high precision time, which is the time of laser echo signal appearance and the period of motor speed signal. According to the scheme, prototype was designed, and the program of the host computer was finished. The experiment of azimuth angle detection was carried out. The experimental results show that, the magnetic-electric detection system uses multiple shield method which can effectively suppress electromagnetic interference. Meanwhile, this system can achieve real time monitoring of the motor speed and range angle solver. Azimuth solution calculation error is in plus or minus 2°. The magnetic-electric detection system can meet the requirement of high precision and anti-interference ability of the azimuth angle measurement of laser fuze. © 2017, Science Press. All right reserved.

Wang J.,Nanjing University of Science and Technology | Wu W.,Nanjing University of Science and Technology
Optics Express | Year: 2017

This paper presents a polarization converter to convert a linearly polarized (LP) incident wave into an outgoing circularly polarized (CP) wave. It is constructed by a 2D array of thin cavities, with each cavity etched with three slots. The front slot is used to couple the LP wave into the cavity, while the backside orthogonal slots are utilized to couple the field out of the cavity with the same amplitude and 90° out-of-phase; subsequently, a CP wave is formed at the other side of the converter. As a proof-of-concept, a sample of the proposed converter is fabricated and measured in the microwave regime. Eventually, a perfect CP wave is demonstrated after the LP wave passes through the converter. The proposed linear-to-circular polarization converter features an extremely low insertion loss of around 0.1 dB and a high polarization conversion efficiency of 0.97. © 2017 Optical Society of America.

Tong B.,Nanjing University of Science and Technology | Liu Y.,Nanjing University of Science and Technology
2016 IEEE International Conference on Robotics and Biomimetics, ROBIO 2016 | Year: 2016

Studies show that multiple modal biometric systems for small-scale populations perform better than single modal biometric systems for robots's recognition. This paper establishes a new fusion method for multiple biometric feature identification which combines visual with auditory information. Before the fusion, speaker recognition based on vector quantization and face recognition based on sparse representation get their single modal similarity and accepted rate respectively, then the similarity is normalized to get the matching score. Finally, fuzzy measure and fuzzy integrals are used for the fusion of speaker recognition and face recognition to obtain the matching result. In the actual environment, the mobile robot utilize this method to realize the recognition. The result of experiment indicates that the performance is better than single modal recognition. © 2016 IEEE.

Zhao J.,Nanjing University of Science and Technology | Xiang X.,Nanjing University of Science and Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

In this paper, we propose a novel video matting approach based on motion estimation. For a given video sequence, we first select some keyframes according to a dynamic rule. Then we segment keyframes into foreground and background using grabcut and automatically propagate these segmentations to the whole video sequence. Finally, we apply guided filter to every frame and its segmentation to get a fine alpha matte sequence. Instead of using optical flow to propagate segmentations, we adopt a motion estimation method which uses a fast block matching algorithm. Experiment results on various video sequences show that our approach not only achieves faster speed in segmentation propagation process but also improves the matting quality compared with methods using optical flow. © 2016 IEEE.

Tang L.,Nanjing University of Science and Technology | Chen X.,Sun Yat Sen University
2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings | Year: 2016

Chen T.-T.,Nanjing University of Science and Technology | Cai C.,Nanjing University of Science and Technology
Synlett | Year: 2017

Copper triflate catalyzed oxidative C–H functionalization of glycine derivatives with allyltributyltin has been established using oxygen or tert-butyl hydroperoxide as oxidant. Various glycine esters and glycine amides were suitable substrates for this oxidative allylation reaction and afforded the desired homoallylic amines in moderate to good yields. Copyright © 2017, Georg Thieme Verlag. All rights reserved.

Li J.,Nanjing University of Science and Technology | Li J.,Utah State University | Ren W.,University of California at Riverside | Xu S.,Nanjing University of Science and Technology
IEEE Transactions on Automatic Control | Year: 2012

This note studies the distributed containment control problem for a group of autonomous vehicles modeled by double-integrator dynamics with multiple dynamic leaders. The objective is to drive the followers into the convex hull spanned by the dynamic leaders under the constraints that the velocities and the accelerations of both the leaders and the followers are not available, the leaders are neighbors of only a subset of the followers, and the followers have only local interaction. Two containment control algorithms via only position measurements of the agents are proposed. Theoretical analysis shows that the followers will move into the convex hull spanned by the dynamic leaders if the network topology among the followers is undirected, for each follower there exists at least one leader that has a directed path to the follower, and the parameters in the algorithm are properly chosen. Numerical results are provided to illustrate the theoretical results. © 2011 IEEE.

van Hees H.,Frankfurt Institute for Advanced Studies | van Hees H.,Institute for Theoretical Physics | He M.,Nanjing University of Science and Technology | Rapp R.,Texas A&M University
Nuclear Physics A | Year: 2015

We compute the spectra and elliptic flow of thermal photons emitted in ultrarelativistic heavy-ion collisions (URHICs) at RHIC and LHC. The thermal emission rates are taken from complete leading-order rates for the QGP and hadronic many-body calculations including baryons and antibaryons, as well as meson-exchange reactions (including Bremsstrahlung). We first update previous thermal fireball calculations by implementing a lattice-QCD based equation of state and extend them to compare to recent LHC data. We then scrutinize the space-time evolution of Au-Au collisions at RHIC by employing an ideal hydrodynamic model constrained by bulk- and multistrange-hadron spectra and elliptic flow, including a non-vanishing initial flow. We systematically compare the evolutions of temperature, radial flow, azimuthal anisotropy and four-volume, and exhibit the temperature profile of thermal photon radiation. Based on these insights, we put forward a scenario with a "pseudo-critical enhancement" of thermal emission rates, and investigate its impact on RHIC and LHC direct photon data. © 2014 Elsevier B.V.

Zuo C.,Nanjing University of Science and Technology | Zuo C.,Nanyang Technological University | Zuo C.,Beijing Institute of Technology | Chen Q.,Nanjing University of Science and Technology | And 3 more authors.
Optics Express | Year: 2013

Several existing strategies for estimating the axial intensity derivative in the transport-of-intensity equation (TIE) from multiple intensity measurements have been unified by the Savitzky-Golay differentiation filter - an equivalent convolution solution for differentiation estimation by least-squares polynomial fitting. The different viewpoint from the digital filter in signal processing not only provides great insight into the behaviors, the shortcomings, and the performance of these existing intensity derivative estimation algorithms, but more important, it also suggests a new way of improving solution strategies by extending the applications of Savitzky-Golay differentiation filter in TIE. Two novel methods for phase retrieval based on TIE are presented - the first by introducing adaptivedegree strategy in spatial domain and the second by selecting optimal spatial frequencies in Fourier domain. Numerical simulations and experiments verify that the second method outperforms the existing methods significantly, showing reliable retrieved phase with both overall contrast and fine phase variations well preserved. © 2013 Optical Society of America.

Wang L.,Nanjing University of Science and Technology | Wang L.,National University of Singapore | Guo Y.-X.,National University of Singapore | Sheng W.-X.,Nanjing University of Science and Technology
IEEE Transactions on Antennas and Propagation | Year: 2013

A 4× 4 L-probe patch antenna array using multilayer low temperature co-fired ceramic (LTCC) technology is presented for 60-GHz band applications. The proposed antenna array is designed with a high gain in the impedance bandwidth by introducing a novel soft-surface structure. The soft-surface structure comprised of metal strips and via fences reduces the losses caused by severe surface waves and mutual coupling between adjacent elements to improve the radiation performance. The proposed antenna array is convenient for integrated applications. The fabricated antenna array excluding the measurement transition has dimension of 14.4× 14.4× 1 mm3. The simulated and measured impedance and radiation performance are studied and compared. Good agreement is achieved between simulation and measurement. The proposed antenna array shows a wide simulated impedance of 29% from 53 GHz to 71 GHz for S11<-10 dB, measured broadband 3-dB gain bandwidth of 18.3% from 54.5 GHz to 65.5 GHz and the gain up to 17.5 dBi at 60 GHz, respectively. © 1963-2012 IEEE.

Cao X.,Nanjing University of Science and Technology | Jiang S.,Nanjing University of Science and Technology | Yu C.,Nanjing University of Science and Technology | Wang Y.,Nanjing University of Science and Technology | And 3 more authors.
Optics Express | Year: 2014

We present a theoretical investigation of high-order harmonic generation in spatially inhomogeneous two-color laser fields by solving three dimensional time dependent Schrödinger equation. The cutoff in the harmonic spectra can be significantly extended by means of our proposed method (i.e., from helium interacting with the plasmon-enhanced two-color laser fields), and an ultrabroad supercontinuum up to 1.5 keV is generated by selecting proper carrier-envelope phase of the controlling field. Moreover, classical trajectory extraction, time-dependent ionization and recombination rates, and time-frequency analyses are used to explain the generation of this ultrabroadband supercontinuum. As a result, an isolated 8.8 attosecond pulse can be generated directly by the superposition of the supercontinuum harmonics. © 2014 Optical Society of America.

Ren R.,Nanjing University of Science and Technology | Ren R.,National University of Singapore | Guo Y.,National University of Singapore | Zhu R.,Nanjing University of Science and Technology
Optics Letters | Year: 2012

This Letter presents a crystalline silicon thin film solar cell model with Si nanowire arrays surface decoration and metallic nanostructure patterns on the back reflector. The nanostructured Ag back reflector can significantly enhance the absorption in the near-infrared spectrum. Furthermore, by inserting a ZnO:Al layer between the silicon substrate and nanostructured Ag back reflector, the absorption loss in the Ag back reflector can be clearly depressed, contributing to a maximum Jsc of 28.4 mA/cm2. A photocurrent enhancement of 22% is achieved compared with a SiNW solar cell with a planar Ag back reflector. © 2012 Optical Society of America.

Zhou Q.,Nanjing University of Science and Technology | Shi P.,University of Adelaide | Shi P.,Victoria University of Melbourne | Xu S.,Nanjing University of Science and Technology | Li H.,Bohai University
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

This paper considers the problem of observer-based adaptive neural network (NN) control for a class of single-input single-output strict-feedback nonlinear stochastic systems with unknown time delays. Dynamic surface control is used to avoid the so-called explosion of complexity in the backstepping design process. Radial basis function NNs are directly utilized to approximate the unknown and desired control input signals instead of the unknown nonlinear functions. The proposed adaptive NN output feedback controller can guarantee all the signals in the closed-loop system to be mean square semi-globally uniformly ultimately bounded. Simulation results are provided to demonstrate the effectiveness of the proposed methods. © 2012 IEEE.

Sheng C.,Nanjing University of Science and Technology | Sheng C.,University of Utah | Zhang C.,University of Utah | Zhai Y.,University of Utah | And 5 more authors.
Physical Review Letters | Year: 2015

We studied the ultrafast transient response of photoexcitations in two hybrid organic-inorganic perovskite films used for high efficiency photovoltaic cells, namely, CH3NH3PbI3 and CH3NH3PbI1.1Br1.9 using polarized broadband pump-probe spectroscopy in the spectral range of 0.3-2.7 eV with 300 fs time resolution. For CH3NH3PbI3 with above-gap excitation we found both photogenerated carriers and excitons, but only carriers are photogenerated with below-gap excitation. In contrast, mainly excitons are photogenerated in CH3NH3PbI1.1Br1.9. Surprisingly, we also discovered in CH3NH3PbI3, but not in CH3NH3PbI1.1Br1.9, transient photoinduced polarization memory for both excitons and photocarriers, which is also reflected in the steady state photoluminescence. From the polarization memory dynamics we obtained the excitons diffusion constant in CH3NH3PbI3, D≈0.01cm2s-1. © 2015 American Physical Society.

Zeng Z.,Nanjing University of Science and Technology | Ai Y.,Singapore University of Technology and Design | Qian S.,Old Dominion University
Physical Chemistry Chemical Physics | Year: 2014

Mimicking biological ion channels capable of pH-regulated ionic transport, synthetic nanopores functionalized with pH-tunable polyelectrolyte (PE) brushes have been considered as versatile tools for active transport control of ions, fluids, and bioparticles on the nanoscale. The ionic current rectification (ICR) phenomenon through a conical nanopore functionalized with PE brushes whose charge highly depends upon the local solution properties (i.e., pH and background salt concentration) is studied theoretically for the first time. The results show that the rectification magnitude, as well as the preferential rectification direction, is sensitive to the pH stimulus. The bulk concentration of the background salt can also significantly influence the charge of the PE brushes and accordingly affect the ICR phenomenon. The obtained results provide an insightful understanding of the pH-regulated ICR and guidelines for designing nanopores functionalized with PE brushes for pH-tunable applications. © 2014 the Owner Societies.

Chen W.,Nanjing University of Science and Technology | Wang L.,Nanjing University of Posts and Telecommunications
Neurocomputing | Year: 2013

In this paper, the problem of stochastic stability of neutral-type neural networks with Markovian jumping parameters is considered. By choosing an mode-dependent Lyapunov-Krasovskii functional, novel delay-dependent stochastically stable conditions are derived in terms of linear matrix inequalities. Numerical examples are given to illustrate the effectiveness of the proposed approach. © 2013 Elsevier B.V.

Lu C.,National University of Singapore | Tang J.,Nanjing University of Science and Technology | Yan S.,National University of Singapore | Lin Z.,Peking University
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2014

As surrogate functions of 0-norm, many nonconvex penalty functions have been proposed to enhance the sparse vector recovery. It is easy to extend these nonconvex penalty functions on singular values of a matrix to enhance low-rank matrix recovery. However, different from convex optimization, solving the nonconvex low-rank minimization problem is much more challenging than the nonconvex sparse minimization problem. We observe that all the existing nonconvex penalty functions are concave and monotonically increasing on [0, ∞). Thus their gradients are decreasing functions. Based on this property, we propose an Iteratively Reweighted Nuclear Norm (IRNN) algorithm to solve the nonconvex nonsmooth low-rank minimization problem. IRNN iteratively solves a Weighted Singular Value Thresholding (WSVT) problem. By setting the weight vector as the gradient of the concave penalty function, the WSVT problem has a closed form solution. In theory, we prove that IRNN decreases the objective function value monotonically, and any limit point is a stationary point. Extensive experiments on both synthetic data and real images demonstrate that IRNN enhances the low-rank matrix recovery compared with state-of-the-art convex algorithms. © 2014 IEEE.

Chu H.,National University of Singapore | Chu H.,Nanjing University of Science and Technology | Guo Y.-X.,National University of Singapore | Wang Z.,Nanjing Electronic Devices Institute
IEEE Transactions on Antennas and Propagation | Year: 2013

Wideband 60-GHz vertical off-center dipole antenna and its arrays on low-temperature cofired ceramic substrate are presented in this paper. The dipole antenna is designed using the off-center-fed technology to cover all the four channels defined in 60-GHz standards from 57 to 66 GHz. A 4 \times 4 planar array is optimized to achieve a maximum gain of 15.6 dBi at 60 GHz and above 10.2 dBi in the passband, while a beam-steering array is optimized to give a 5-dB measured beamwidth wider than 80\circ at 60 GHz. Measured results indicate our designs meet the above requirements well and satisfy 60-GHz applications. © 1963-2012 IEEE.

Chen W.,Nanjing University of Science and Technology | Wang L.,Nanjing University of Posts and Telecommunications
Journal of the Franklin Institute | Year: 2014

In this paper, the problem of H∞ filtering of uncertain time-delay systems with Markovian jumping parameters is considered. Firstly, by utilizing the delay-partitioning idea, an augmented mode-dependent Lyapunov functional is employed to analyze the stochastic stability and H∞ performance of the resulting filtering error systems. It is noted that the derived performance analysis results are less conservative than the recent ones in the literature. Secondly, based on the criteria obtained, a desired filter can be constructed by introducing a given nonsingular matrix and a scalar. Numerical examples are given to illustrate the effectiveness of the proposed approach. © 2013 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Yeh L.-H.,National Yunlin University of Science and Technology | Hughes C.,Old Dominion University | Zeng Z.,Nanjing University of Science and Technology | Qian S.,Old Dominion University
Analytical Chemistry | Year: 2014

Inspired by ion channels in biological cells where the intracellular and extracellular ionic concentrations are typically different, a salt concentration gradient through a charged nanopore is proposed to actively regulate its ion transport and selectivity. Results obtained show that, in addition to the ion current rectification phenomenon, a reversed ion selectivity of the nanopore occurs when the concentration gradient is sufficiently large. In addition, if the directions of the applied concentration gradient and electric field are identical, a reversed magnified electric field occurs near the cathode side of the nanopore. This induced field can be used to enhance the capture rate of biomolecules and is therefore capable of improving the performance of single biomolecule sensing using nanopores. © 2014 American Chemical Society.

Ai Y.,Singapore University of Technology and Design | Zeng Z.,Nanjing University of Science and Technology | Qian S.,Old Dominion University
Journal of Colloid and Interface Science | Year: 2014

Under an AC electric field, individual particles in close proximity induce spatially non-uniform electric field around each other, accordingly resulting in mutual dielectrophoretic (DEP) forces on these particles. The resulting attractive DEP particle-particle interaction could assemble individual colloidal particles or biological cells into regular patterns, which has become a promising bottom-up fabrication technique for bio-composite materials and microscopic functional structures. In this study, we developed a transient multiphysics model under the thin electric double layer (EDL) assumption, in which the fluid flow field, AC electric field and motion of finite-size particles are simultaneously solved using an Arbitrary Lagrangian-Eulerian (ALE) numerical approach. Numerical simulations show that negative DEP particle-particle interaction always tends to attract particles and form a chain parallel to the applied electric field. Particles usually accelerate at the first stage of the attractive motion due to an increase in the DEP interactive force, however, decelerate until stationary at the second stage due to a faster increase in the repulsive hydrodynamic force. Identical particles move at the same speed during the interactive motion. In contrast, smaller particles move faster than bigger particles during the attractive motion. The developed model explains the basic mechanism of AC DEP-based particle assembly technique and provides a versatile tool to design microfluidic devices for AC DEP-based particle or cell manipulation. © 2013 Elsevier Inc.

Xia H.,Nanjing University of Science and Technology | Luo Z.,National University of Singapore | Xie J.,National University of Singapore
Nanotechnology Reviews | Year: 2014

Lithium-ion (Li-ion) batteries with high energy and power are promising power sources for electric vehicles (including hybrid electric vehicles). One of the challenges is to develop advanced anode materials with high safety, good cycling stability, and fast charge/discharge capabilities. The Li4Ti5O12 spinel is a state-of-the-art Li-ion battery anode material owing to its outstanding safety and excellent structural stability during cycling. However, Li4Ti5O12 large particles still suffer from low ionic conductivity and electronic conductivity, which result in poor rate performance and inhibit its wide practical application. Developing nanostructured electrode materials is one of the most attractive strategies to dramatically enhance the electrochemical performance, including capacity, rate capability, and cycling life. Currently, extensive efforts have been devoted to developing nanostructured Li4Ti5O12 and Li4Ti5O12/carbon nanocomposites to improve their rate performance for high-power Li-ion batteries. In this article, we review the recent progress in developing nanostructured Li4Ti5O12 and Li4Ti5O12/carbon nanocomposites and discuss the benefits of nanostructure and carbon incorporation for the electrochemical performance of Li4Ti5O12-based anodes.

Zhu D.,Nanjing University of Science and Technology | Yuan G.,Nanjing University of Science and Technology | Xia H.,Nanjing University of Science and Technology
Chemical Communications | Year: 2014

Ti nanowire arrays (NAs) prepared by a facile and template-free hydrothermal method were used as three-dimensional (3D) current collectors for the electrodeposition of MnO2. The resulting Ti@MnO2 NAs exhibit remarkable electrochemical behavior with high specific capacitance, good rate performance and desired cycling stability. © 2014 The Royal Society of Chemistry.

Chu H.,Nanjing University of Science and Technology | Shi X.Q.,Nanjing University of Science and Technology | Guo Y.X.,National University of Singapore
Journal of Electromagnetic Waves and Applications | Year: 2011

A novel ultra-wideband (UWB) bandpass filter (BPF) with a notch band is proposed and implemented. The filter is realized by using a high pass filter (HPF) and an array of multiband electromagnetic bandgap (EBG) cells etched on the ground of a 50 Ω microstrip line. The first and third stopband of the designed EBG array generate the edges at each side of the passband of the UWB BPF, while the second stopband creates a very sharp notch response. Since it is the passband of the designed EBG array at lower frequency, a HPF is involved. To the authors' knowledge, we present for the first time a sharp notch band generated by using an EBG array in UWB BPF. The proposed filter was successfully designed, simulated and fabricated. The measured results show that the proposed BPF has a wide bandwidth from 3.8 GHz to 10.1 GHz with a notch response centered at 5.1 GHz. Both simulated and measured results are described. © 2011 VSP.

Shen F.,University of Adelaide | Shen F.,Nanjing University of Science and Technology | Shen C.,University of Adelaide | Shi Q.,University of Adelaide | And 2 more authors.
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2013

Learning based hashing methods have attracted considerable attention due to their ability to greatly increase the scale at which existing algorithms may operate. Most of these methods are designed to generate binary codes that preserve the Euclidean distance in the original space. Manifold learning techniques, in contrast, are better able to model the intrinsic structure embedded in the original high-dimensional data. The complexity of these models, and the problems with out-of-sample data, have previously rendered them unsuitable for application to large-scale embedding, however. In this work, we consider how to learn compact binary embeddings on their intrinsic manifolds. In order to address the above-mentioned difficulties, we describe an efficient, inductive solution to the out-of-sample data problem, and a process by which non-parametric manifold learning may be used as the basis of a hashing method. Our proposed approach thus allows the development of a range of new hashing techniques exploiting the flexibility of the wide variety of manifold learning approaches available. We particularly show that hashing on the basis of t-SNE [29] outperforms state-of-the-art hashing methods on large-scale benchmark datasets, and is very effective for image classification with very short code lengths. © 2013 IEEE.

Xia H.,Nanjing University of Science and Technology | Xiong W.,Nanjing University of Science and Technology | Yao Q.,National University of Singapore | Xie J.,National University of Singapore
Nano Research | Year: 2014

This paper reports a simple yet efficient method for the synthesis of hierarchical TiO2-B nanowire@α-Fe2O3 nanothorn core-branch arrays based on a stepwise hydrothermal approach. The as-fabricated hybrid arrays show impressive performance as a high-capacity anode for lithium-ion batteries. The key design in this study is a core-branch hybrid architecture, which not only provides large surface active sites for lithium ion insertion/extraction, but also enables fast charge transport owing to the reduced diffusion paths for both electrons and lithium ions. The peculiar combination of attributes of TiO2 (good structural stability) and Fe2O3 (large specific capacity) provides the hybrid array electrodes with several desirable electrochemical features: large reversible capacity (∼800 mA·h·g−1 for specific mass capacity and ∼750 μA·h·cm−2 for specific areal capacity), good cycling stability, and high rate capability. The impressive electrochemical performance, together with the facile synthesis procedure, may provide an efficient platform to integrate the TiO2 nanowire@Fe2O3 nanothorn core-branch arrays as a three-dimensional thin film electrode for lithium-ion microbatteries.[Figure not available: see fulltext.]. © 2014, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Xia J.,University of Oklahoma | Chen J.,Nanjing University of Science and Technology | Chen J.,University of Toledo | Piao S.,Peking University | And 4 more authors.
Nature Geoscience | Year: 2014

Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30and 90N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research. © 2014 Macmillan Publishers Limited.

Zhang C.,University of Utah | Sun D.,University of Utah | Sheng C.-X.,University of Utah | Sheng C.-X.,Nanjing University of Science and Technology | And 4 more authors.
Nature Physics | Year: 2015

Magnetic field effects have been a successful tool for studying carrier dynamics in organic semiconductors as the weak spin-orbit coupling in these materials gives rise to long spin relaxation times. As the spin-orbit coupling is strong in organic-inorganic hybrid perovskites, which are promising materials for photovoltaic and light-emitting applications, magnetic field effects are expected to be negligible in these optoelectronic devices. We measured significant magneto-photocurrent, magneto-electroluminescence and magneto-photoluminescence responses in hybrid perovskite devices and thin films, where the amplitude and shape are correlated to each other through the electron-hole lifetime, which depends on the perovskite film morphology. We attribute these responses to magnetic-field-induced spin-mixing of the photogenerated electron-hole pairs with different g-factors - the Δg model. We validate this model by measuring large Δg (∼ 0.65) using field-induced circularly polarized photoluminescence, and electron-hole pair lifetime using picosecond pump-probe spectroscopy.

Xia R.,Nanjing University of Science and Technology | Zong C.,Chinese Academy of Sciences | Hu X.,Nanjing University of Science and Technology | Cambria E.,National University of Singapore
IEEE Intelligent Systems | Year: 2013

Domain adaptation problems often arise often in the field of sentiment classification. Here, the feature ensemble plus sample selection (SS-FE) approach is proposed, which takes labeling and instance adaptation into account. A feature ensemble (FE) model is first proposed to learn a new labeling function in a feature reweighting manner. Furthermore, a PCA-based sample selection (PCA-SS) method is proposed as an aid to FE. Experimental results show that the proposed SS-FE approach could gain significant improvements, compared to FE or PCA-SS, because of its comprehensive consideration of both labeling adaptation and instance adaptation. © 2013 IEEE.

Xia H.,Nanjing University of Science and Technology | Wang Y.,Institute of Chemical and Engineering Sciences, Singapore | Lin J.,Institute of Chemical and Engineering Sciences, Singapore | Lu L.,National University of Singapore
Nanoscale Research Letters | Year: 2012

MnO 2/carbon nanotube [CNT] nanocomposites with a CNT core/porous MnO 2 sheath hierarchy architecture are synthesized by a simple hydrothermal treatment. X-ray diffraction and Raman spectroscopy analyses reveal that birnessite-type MnO 2 is produced through the hydrothermal synthesis. Morphological characterization reveals that three-dimensional hierarchy architecture is built with a highly porous layer consisting of interconnected MnO 2 nanoflakes uniformly coated on the CNT surface. The nanocomposite with a composition of 72 wt.% (K 0.2MnO 2·0.33H 2O)/28 wt.% CNT has a large specific surface area of 237.8 m 2/g. Electrochemical properties of the CNT, the pure MnO 2, and the MnO 2/CNT nanocomposite electrodes are investigated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The MnO 2/CNT nanocomposite electrode exhibits much larger specific capacitance compared with both the CNT electrode and the pure MnO 2 electrode and significantly improves rate capability compared to the pure MnO 2 electrode. The superior supercapacitive performance of the MnO 2/CNT nancomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport. © 2012 Xia et al.

Yang J.,Nanjing University of Science and Technology | Chu D.,National University of Singapore | Zhang L.,Hong Kong Polytechnic University | Xu Y.,Harbin Institute of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

A sparse representation-based classifier (SRC) is developed and shows great potential for real-world face recognition. This paper presents a dimensionality reduction method that fits SRC well. SRC adopts a class reconstruction residual-based decision rule, we use it as a criterion to steer the design of a feature extraction method. The method is thus called the SRC steered discriminative projection (SRC-DP). SRC-DP maximizes the ratio of between-class reconstruction residual to within-class reconstruction residual in the projected space and thus enables SRC to achieve better performance. SRC-DP provides low-dimensional representation of human faces to make the SRC-based face recognition system more efficient. Experiments are done on the AR, the extended Yale B, and PIE face image databases, and results demonstrate the proposed method is more effective than other feature extraction methods based on the SRC. © 2012 IEEE.

Xia H.,Nanjing University of Science and Technology | Li B.,Nanjing University of Science and Technology | Lu L.,National University of Singapore
RSC Advances | Year: 2014

Nanocrystalline Ru film is deposited on Ni foam by a chemical replacement reaction. The deposited Ru film exhibits a mesoporous structure comprising nanocrystallites and nanopores of 2-3 nm in diameter. A 1.8 V symmetric supercapacitor is developed using nanocrystalline Ru films as both negative and positive electrodes. © 2014 The Royal Society of Chemistry.

Jin Z.,Nanjing University of Posts and Telecommunications | Jin Z.,Nanjing University of Science and Technology | Yang X.,Nanjing University of Science and Technology
Journal of Mathematical Imaging and Vision | Year: 2011

In this paper we study a variational model to deal with the speckle noise in ultrasound images. We prove the existence and uniqueness of the minimizer for the variational problem, and derive the existence and uniqueness of weak solutions for the associated evolution equation. Furthermore, we show that the solution of the evolution equation converges weakly in BV and strongly in L 2 to the minimizer as t→∞. Finally, some numerical results illustrate the effectiveness of the proposed model for multiplicative noise removal. © 2010 Springer Science+Business Media, LLC.

Xia H.,Nanjing University of Science and Technology | Ragavendran K.R.,Bar - Ilan University | Xie J.,National University of Singapore | Lu L.,National University of Singapore
Journal of Power Sources | Year: 2012

Ultrafine LiMn 2O 4/carbon nanotube (CNT) nanocomposite is synthesized by a one-step hydrothermal treatment. In the nanocomposite, LiMn 2O 4 nanoparticles of 10-20 nm in diameters are well crystallized and uniformly distributed in the CNT matrix. The CNTs not only provide a conductive matrix, facilitating fast electron transport, but also effectively reduce agglomeration of LiMn 2O 4 nanoparticles. The nano-LiMn 2O 4/CNT nanocomposite exhibits superior rate capability and cycling stability compared with the sol-gel synthesized LiMn 2O 4, making it promising for high-power applications. © 2012 Elsevier B.V. All rights reserved.

Tang G.,Nanjing University of Science and Technology | Shi X.,Nanjing University of Science and Technology | Huo C.,China Institute of Metrology | Wang Z.,Nanjing University
Ceramics International | Year: 2013

The fabrication and magnetic characteristics of Ni and Cu co-doped ZnO nanorods are reported. The Ni and Cu co-doped ZnO nanorods are synthesized by a facile hydrothermal method. Structural characterizations reveal that Ni and Cu ions enter into ZnO lattices without any secondary phases. SEM images show that they are regular nanorods. Magnetic measurements indicate that the obtained rod arrays exhibit room-temperature ferromagnetic behaviors. The exchange interaction between free delocalized carriers (holes from valence band) and the localized d spins of Ni and Cu ions is considered as the cause of the room-temperature ferromagnetism. © 2012 Elsevier Ltd and Techna Group S.r.l.

Ye J.,Nanjing University of Science and Technology | Ye J.,Nanjing University of Posts and Telecommunications | Jin Z.,Nanjing University of Science and Technology
Neurocomputing | Year: 2014

In past decades, tremendous growths in the amount of text documents and images have become omnipresent, and it is very important to group them into clusters upon desired. Recently, matrix factorization based techniques, such as Non-negative Matrix Factorization (NMF) and Concept Factorization (CF), have yielded impressive results for clustering. However, both of them effectively see only the global Euclidean geometry, whereas the local manifold geometry is not fully considered. Recent research has shown that not only the observed data are found to lie on a nonlinear low dimensional manifold, namely data manifold, but also the features lie on a manifold, namely feature manifold. In this paper, we propose a novel algorithm, called dual-graph regularized concept factorization for clustering (GCF), which simultaneously considers the geometric structures of both the data manifold and the feature manifold. As an extension of GCF, we extend that our proposed method can also be apply to the negative dataset. Moreover, we develop the iterative updating optimization schemes for GCF, and provide the convergence proof of our optimization scheme. Experimental results on TDT2 and Reuters document datasets, COIL20 and PIE image datasets demonstrate the effectiveness of our proposed method. © 2014 Elsevier B.V.

Wu F.,Nanjing Forestry University | Liu Y.,Nanjing Forestry University | Yu G.,Nanjing Forestry University | Shen D.,Nanjing Forestry University | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2012

Although graphitic C3N4 (g-C3N 4) has been demonstrated to be a potential candidate for solar cell absorber and photovoltaic materials, the application has been limited by the low photoconversion efficiency in the visible range. Here, we explored that a g-C3N4 bilayer has much better visible-light adsorption than a single layer via first-principles calculations, and the calculated optical adsorption threshold of bilayer significantly shifts downward by 0.8 eV, which is induced by the interlayer coupling. Additionally, we also found that the optical energy gap of bilayer can be engineered by the external electric field. The insights obtained in this study are general and will be helpful for future studies of two-dimensional solar cell absorber and photovoltaic materials. © 2012 American Chemical Society.

Zhou Q.,Nanjing University of Science and Technology | Zhou Q.,University of Portsmouth | Shi P.,University of South Wales | Shi P.,Victoria University of Melbourne | And 3 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2013

In this paper, the problem of adaptive fuzzy tracking control via output feedback for a class of uncertain single-input single-output (SISO) strict-feedback nonlinear systems with unknown time-delay functions is investigated. Dynamic surface control technique is used to avoid the problem of 'explosion of complexity,' which is caused by repeated differentiation of certain nonlinear functions in the backstepping design process. In addition, the fuzzy logic systems are utilized to approximate the unknown and desired control input signals directly instead of the unknown nonlinear functions. The designed controller can guarantee all the signals in the closed-loop system to be semiglobally uniformly ultimately bounded and the tracking error to converge to a small neighborhood of the origin. Simulations results are provided to demonstrate the effectiveness of the proposed methods. © 1993-2012 IEEE.

Gao Y.,Tsinghua National Laboratory for Information Sciences and Technology | Tang J.,Nanjing University of Science and Technology | Hong R.,Hefei University of Technology | Yan S.,National University of Singapore | And 3 more authors.
IEEE Transactions on Image Processing | Year: 2012

Recently, extensive research efforts have been dedicated to view-based methods for 3-D object retrieval due to the highly discriminative property of multiviews for 3-D object representation. However, most of state-of-the-art approaches highly depend on their own camera array settings for capturing views of 3-D objects. In order to move toward a general framework for 3-D object retrieval without the limitation of camera array restriction, a camera constraint-free view-based (CCFV) 3-D object retrieval algorithm is proposed in this paper. In this framework, each object is represented by a free set of views, which means that these views can be captured from any direction without camera constraint. For each query object, we first cluster all query views to generate the view clusters, which are then used to build the query models. For a more accurate 3-D object comparison, a positive matching model and a negative matching model are individually trained using positive and negative matched samples, respectively. The CCFV model is generated on the basis of the query Gaussian models by combining the positive matching model and the negative matching model. The CCFV removes the constraint of static camera array settings for view capturing and can be applied to any view-based 3-D object database. We conduct experiments on the National Taiwan University 3-D model database and the ETH 3-D object database. Experimental results show that the proposed scheme can achieve better performance than state-of-the-art methods. © 2011 IEEE.

Shen C.,University of Adelaide | Wang P.,Beihang University | Shen F.,Nanjing University of Science and Technology | Wang H.,Xiamen University | Wang H.,University of Adelaide
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2012

It has been shown that the Universum data, which do not belong to either class of the classification problem of interest, may contain useful prior domain knowledge for training a classifier [1], [2]. In this work, we design a novel boosting algorithm that takes advantage of the available Universum data, hence the name UBoost. UBoost is a boosting implementation of Vapnik's alternative capacity concept to the large margin approach. In addition to the standard regularization term, UBoost also controls the learned model's capacity by maximizing the number of observed contradictions. Our experiments demonstrate that UBoost can deliver improved classification accuracy over standard boosting algorithms that use labeled data alone. © 2012 IEEE.

Li Z.C.,Nanjing University of Science and Technology | Li Z.C.,Nanjing Forestry University | Wang J.,Nanjing University of Science and Technology
Smart Materials and Structures | Year: 2012

This research aims to design and control a full scale gun recoil buffering system which works under real firing impact loading conditions. A conventional gun recoil absorber is replaced with a controllable magnetorheological (MR) fluid damper. Through dynamic analysis of the gun recoil system, a theoretical model for optimal design and control of the MR fluid damper for impact loadings is derived. The optimal displacement, velocity and optimal design rules are obtained. By applying the optimal design theory to protect against impact loadings, an MR fluid damper for a full scale gun recoil system is designed and manufactured. An experimental study is carried out on a firing test rig which consists of a 30mm caliber, multi-action automatic gun with an MR damper mounted to the fixed base through a sliding guide. Experimental buffering results under passive control and optimal control are obtained. By comparison, optimal control is better than passive control, because it produces smaller variation in the recoil force while achieving less displacement of the recoil body. The optimal control strategy presented in this paper is open-loop with no feedback system needed. This means that the control process is sensor-free. This is a great benefit for a buffering system under impact loading, especially for a gun recoil system which usually works in a harsh environment. © 2012 IOP Publishing Ltd.

Tang J.,Nanjing University of Science and Technology | Zha Z.-J.,National University of Singapore | Tao D.,Intelligent Systems Technology, Inc. | Chua T.-S.,National University of Singapore
IEEE Transactions on Image Processing | Year: 2012

User interaction is an effective way to handle the semantic gap problem in image annotation. To minimize user effort in the interactions, many active learning methods were proposed. These methods treat the semantic concepts individually or correlatively. However, they still neglect the key motivation of user feedback: to tackle the semantic gap. The size of the semantic gap of each concept is an important factor that affects the performance of user feedback. User should pay more efforts to the concepts with large semantic gaps, and vice versa. In this paper, we propose a semantic-gap-oriented active learning method, which incorporates the semantic gap measure into the information-minimization- based sample selection strategy. The basic learning model used in the active learning framework is an extended multilabel version of the sparse-graph-based semisupervised learning method that incorporates the semantic correlation. Extensive experiments conducted on two benchmark image data sets demonstrated the importance of bringing the semantic gap measure into the active learning process. © 2011 IEEE.

Xia H.,Nanjing University of Science and Technology | Shirley Meng Y.,University of California at San Diego | Yuan G.,Nanjing University of Science and Technology | Cui C.,Nanjing University of Science and Technology | Lu L.,National University of Singapore
Electrochemical and Solid-State Letters | Year: 2012

A novel symmetric RuO 2RuO 2 supercapacitor with a high operating voltage of 1.6 V is built using the nanocrystalline hydrous RuO 2. The symmetric supercapacitor exhibits an energy density of 18.77 Wh kg -1 at a power density of 500 W kg -1 based on the total mass of active electrode material and excellent cycling stability and power capability. These results demonstrate the potentialities of using RuO 2 for symmetric supercapacitor or using RuO 2 as negative electrode for asymmetric supercapacitor with high energy density. © 2012 The Electrochemical Society.

Camarillo-Cisneros J.,Fritz Haber Institute | Camarillo-Cisneros J.,CIMAV | Liu W.,Fritz Haber Institute | Liu W.,Nanjing University of Science and Technology | Tkatchenko A.,Fritz Haber Institute
Physical Review Letters | Year: 2015

The study of how molecules adsorb, diffuse, interact, and desorb from imperfect surfaces is essential for a complete understanding of elementary surface processes under relevant pressure and temperature conditions. Here we use first-principles calculations to study the adsorption of benzene and naphthalene on a vicinal Cu(443) surface with the aim to gain insight into the behavior of aromatic hydrocarbons on realistic surfaces at a finite temperature. Upon strong adsorption at step edges at a low temperature, the molecules then migrate from the step to the (111) terraces, where they can freely diffuse parallel to the step edge. This migration happens at temperatures well below the onset of desorption, suggesting a more complex dynamical picture than previously proposed from temperature-programed desorption studies. The increase of the adsorption strength observed in experiments for Cu(443) when compared to Cu(111) is explained by a stronger long-range van der Waals attraction between the hydrocarbons and the step edges of the Cu(443) surface. Our calculations highlight the need for time-resolved experimental studies to fully understand the dynamics of molecular layers on surfaces. © 2015 American Physical Society.

Zhao H.,Huaiyin Institute of Technology | Ren W.,University of California at Riverside | Yuan D.,Nanjing University of Science and Technology | Chen J.,Beijing Institute of Technology
Systems and Control Letters | Year: 2012

This paper deals with the distributed discrete-time coordinated tracking problem for multi-agent systems with Markovian switching topologies. In the multi-agent team, only some of the agents can obtain the leader's state directly. The leader's state considered is time varying. We present necessary and sufficient conditions for boundedness of the tracking error system and show the ultimate bound of the tracking errors. A linear matrix inequality approach is developed to determine the allowable sampling period and the feasible control gain. A simulation example is given to illustrate the effectiveness of the results. © 2012 Elsevier Ltd. All rights reserved.

Xu L.,Nanjing University of Information Science and Technology | Li X.,Nanjing University of Science and Technology | Chen Y.,Nanjing University of Information Science and Technology | Xu F.,Nanjing University of Information Science and Technology
Applied Surface Science | Year: 2011

In this work, ZnO thin films with different thickness were prepared by sol-gel method on glass substrates and the structural and optical properties of these films were studied by X-ray diffractometer, atomic force microscope, UV-visible spectrophotometer, ellipsometer and fluorophotometer, respectively. The structural analyses show that all the samples have a wurtzite structure and are preferentially oriented along the c-axis perpendicular to the substrate surface. The growth process of highly c-axis oriented ZnO thin films derived from sol-gel method is a self-template process. With the increase of film thickness, the structural disorder decreases and the crystalline quality of the films is gradually improved. A transition of crystal growth mode from vertical growth to lateral growth is observed and the transition point is found between 270 and 360 nm thickness. The optical analyses show that with the increase of film thickness, both the refractive index and ultraviolet emission intensity are improved. However, the transmittance in the visible range is hardly influenced by the film thickness, and the averages are all above 80%. © 2010 Elsevier B.V.

Huang X.,Nanjing University of Information Science and Technology | Zhang J.,Nanjing Center | Xiao S.,Nanjing University of Information Science and Technology | Sang T.,Nanjing University of Science and Technology | Chen G.,Nanjing University of Information Science and Technology
Materials Letters | Year: 2014

The ZnFe2O4 ferrite nanoparticle and nanofiber were synthesized by electrospinning method. The phase composition, morphology, magnetic and electromagnetic properties were analyzed. The results showed that both the samples exhibited a pure phase of spinel type ferrite. The ZnFe 2O4 ferrite nanoparticle was aggregated, while the ZnFe2O4 ferrite nanofiber performed the homogeneous nano-fibrous shape as well as single-particle-chain structure. The magnetic analysis indicated that the ZnFe2O4 ferrite nanofiber showed ferromagnetic behaviour. Moreover, the dielectric loss and magnetic loss properties of ZnFe2O4 ferrite nanofiber were both enhanced due to its better dipole polarization, interfacial polarization and shape anisotropy. © 2014 Elsevier B.V.

Chen Y.-Y.,Nanjing University of Information Science and Technology | Wang J.,Nanjing University of Science and Technology | Wang Q.-H.,Nanjing University of Science and Technology | Li Z.-H.,Nanjing University of Science and Technology
Optics Letters | Year: 2012

In this Letter, moiré and emission tomography are integrated to visualize and diagnose high-temperature flow fields, and a jet flame is chosen as a practical example for experiment. The refractive index and intensity distributions are simultaneously obtained by moiré and emission tomography, respectively. Based on the intensity distribution, the structure of the jet flame is well visualized, so that the spatial distribution of species composition can be considered in the temperature reconstruction process. Finally, the refractive index and intensity distributions are matched, and a partition model is adopted to reconstruct the temperature distribution of the jet flame. © 2012 Optical Society of America.

Kowalczyk P.J.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Kowalczyk P.J.,University of Lodz | Mahapatra O.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Brown S.A.,MacDiarmid Institute for Advanced Materials and Nanotechnology | And 4 more authors.
Nano Letters | Year: 2013

We show that bismuth nanostructures form three-dimensional patterns governed by two-dimensional electronic effects. Scanning tunneling microscopy reveals that both the vertical and the lateral dimensions of the structures strongly favor certain values and that the preferred widths are substantially different for each preferred height. First-principles calculations demonstrate that this vertical-lateral correlation is governed by the Fermi surface topology and that this is itself sensitively dependent on the dimensions of the structure. © 2012 American Chemical Society.

Zuo C.,Nanjing University of Science and Technology | Zuo C.,Nanyang Technological University | Chen Q.,Nanjing University of Science and Technology | Huang L.,Brookhaven National Laboratory | Asundi A.,Nanyang Technological University
Optics Express | Year: 2014

The transport of intensity equation (TIE) has long been recognized as a quantitative method for phase retrieval and phase contrast imaging. However, it is shown that the most widely accepted fast Fourier transform (FFT) based solutions do not provide an exact solution to the TIE in general. The root of the problem lies in the so-called "Teague's assumption" that the transverse flux is considered to be a conservative field, which cannot be satisfied for a general object. In this work, we present the theoretical analysis of the phase discrepancy owing to the Teague's assumption, and derive the necessary and sufficient conditions for the FFT-based solution to coincide with the exact phase. An iterative algorithm is then proposed aiming to compensate such phase discrepancy in a simple yet effective manner. © 2014 Optical Society of America.

Cong S.,Heilongjiang University | Zou Y.,Nanjing University of Science and Technology
International Journal of Systems Science | Year: 2010

On the basis of the Lyapunov-Krasovskii method, the exponential stability in the mean square sense is investigated for Ito stochastic systems with Markovian switching and time-varying delay. The statistic properties of the Markov process and Brownian motion are employed to compute the constructed Lyapunov-Krasovskii functional of a rather general form. This enables us to make sense of the challenging problems in the stochastic framework, and then find a way to extend the techniques developed in the deterministic framework. Therefore, the stability conditions are established with the aid of some slack matrices and the boundary conditions on time-varying delay. Numerical examples are given to demonstrate the reduced conservatism. © 2010 Taylor & Francis.

Chen M.Z.Q.,University of Hong Kong | Hu Y.,Nanjing University of Science and Technology | Huang L.,University of Hong Kong | Huang L.,Zhejiang Institute of Research and Innovation | Chen G.,City University of Hong Kong
Journal of Sound and Vibration | Year: 2014

This paper investigates the influence of inerter on the natural frequencies of vibration systems. First of all, the natural frequencies of a single-degree-of-freedom (SDOF) system and a two-degree-of-freedom (TDOF) system are derived algebraically and the fact that the inerter can reduce the natural frequencies of these systems is demonstrated. Then, to further investigate the influence of inerter in a general vibration system, a multi-degree-of-freedom system (MDOF) is considered. Sensitivity analysis is performed on the natural frequencies and mode shapes to demonstrate that the natural frequencies of the MDOF system can always be reduced by increasing the inertance of any inerter. The condition for a general MDOF system of which the natural frequencies can be reduced by an inerter is also derived. Finally, the influence of the inerter position on the natural frequencies is investigated and the efficiency of inerter in reducing the largest natural frequencies is verified by simulating a six-degree-of-freedom system, where a reduction of more than 47 percent is obtained by employing only five inerters. © 2013 Elsevier Ltd.

Xu L.,Nanjing University of Information Science and Technology | Li X.,Nanjing University of Science and Technology
Journal of Crystal Growth | Year: 2010

In this work, Fe-doped ZnO thin films were prepared by sol-gel method on Si and glass substrates and influence of Fe-doping concentration on the structural and optical properties of the films was studied. The X-ray diffraction (XRD) analyses show that all the ZnO thin films prepared in this work have a hexagonal wurtzite structure and are preferentially oriented along the c-axis perpendicular to the substrate surface. After 1 at% Fe is doped, the crystalline quality and the preferential orientation of ZnO thin film are improved. However, when Fe-doping concentration is above 1 at%, the crystalline quality and the preferential orientation of ZnO thin film is weakened in turn. The surface morphology analyses of the samples show that the ZnO grain sizes tend to decrease with the increase of Fe-doping concentration. Fe-incorporation hardly influences the transmittance in the visible range, but the optical band-gaps of ZnO thin films gradually increase with the improved Fe-doping concentration. The photoluminescence spectra display that all the samples have an ultraviolet emission peak centered at 381 nm and the 1 at% Fe-doped ZnO thin film has the strongest ultraviolet emission peak. The above results suggest that 1 at% Fe-incorporation can improve the crystalline quality and enhance the ultraviolet emission of ZnO thin film. © 2009 Elsevier B.V. All rights reserved.

Xu L.,Nanjing University of Information Science and Technology | Zheng G.,Nanjing University of Information Science and Technology | Miao J.,Nanjing University of Information Science and Technology | Xian F.,Nanjing University of Science and Technology
Applied Surface Science | Year: 2012

In this work, ZnO thin films were prepared by sol-gel method and the dependence of structural and optical properties of these films on sol concentrations was deeply investigated. Unlike the previous studies, the ZnO thin films deposited in this study have approximately equal thickness, which excludes the influence of film thickness on the physical properties. The results show that low sol concentration is favorable for obtaining high c-axis oriented ZnO thin films with good crystalline quality. When the sol concentration is above 0.7 mol/L, the degree of c-axis orientation of ZnO thin films decreases and the optical quality is also degraded. Photoluminescence spectra indicate that the defect-related blue emission is increased with the enhancement of sol concentration. The mechanism of the blue emission is analyzed. The reason why high sol concentration is unfavorable for formation of high c-axis oriented ZnO thin films and obtaining high optical quality is also discussed. © 2012 Elsevier B.V. All rights reserved.

Ma Q.,Nanjing University of Science and Technology | Wang Z.,Shandong University of Science and Technology | Miao G.,Nanjing University of Information Science and Technology
Journal of the Franklin Institute | Year: 2014

This paper addresses the group consensus problem of second-order nonlinear multi-agent systems through leader-following approach and pinning control. The network topology is assumed to be directed and weakly connected. The pinning consensus protocol is designed according to the agent property, that is, the inter-act agent and the intra-act agent. Some consensus criteria are proposed to guarantee that the agents asymptotically follow the virtual leader in each group, while agents in different groups behave independently. Numerical example is also provided to demonstrate the effectiveness of the theoretical analysis. © 2013 The Franklin Institute. Published by Elsevier Ltd. All right sreserved.

Wang X.,Nanjing University of Science and Technology | Wang X.,University of Illinois at Urbana - Champaign | Bian G.,University of Illinois at Urbana - Champaign | Miller T.,University of Illinois at Urbana - Champaign | Chiang T.-C.,University of Illinois at Urbana - Champaign
Physical Review Letters | Year: 2012

Topological surface states are protected against local perturbations, but this protection does not extend to chemical reaction over the whole surface, as demonstrated by theoretical studies of the oxidation of Bi 2Se 3 and its effects on the surface spin polarization and current. While chemisorption of O 2 largely preserves the topological surface states, reaction with atomic O removes the original surface states and yields two new sets of surface states. One set forms a regular Dirac cone but is topologically trivial. The other set, while topologically relevant, forms an unusual rounded Dirac cone. The details are governed by the hybridization interaction at the interface. © 2012 American Physical Society.

Bian G.,University of Illinois at Urbana - Champaign | Wang X.,University of Illinois at Urbana - Champaign | Wang X.,Nanjing University of Science and Technology | Liu Y.,University of Illinois at Urbana - Champaign | And 2 more authors.
Physical Review Letters | Year: 2012

Spin-polarized gapless surface states in topological insulators form chiral Dirac cones. When such materials are reduced to thin films, the Dirac states on the two faces of the film can overlap and couple by quantum tunneling, resulting in a thickness-dependent insulating gap at the Dirac point. Calculations for a freestanding Sb film with a thickness of four atomic bilayers yield a gap of 36 meV, yet angle-resolved photoemission measurements of a film grown on Si(111) reveal no gap formation. The surprisingly robust Dirac cone is explained by calculations in terms of interfacial interaction. © 2012 American Physical Society.

Xie Y.,Shanghai Dianji University | Feng Y.,Nanjing University of Science and Technology | Qiu Y.,Nanjing University of Science and Technology
Renewable Energy | Year: 2013

Wind energy has been identified in China as an important alternative energy source to balance its energy mix. By the end of 2012, wind power (2%) has surpassed nuclear power to become China's 3rd largest energy resource of electricity, only behind thermal power and hydropower. The rapid growth of China wind power industry in recent years has made China become the biggest market in the world. Meanwhile, it has created a big market for educational institutions to provide wind energy related education and training. The main objective of this study is to review current wind energy education and training in Chinese universities and training centers. Most of wind energy courses are provided by public universities because they have been accredited by Ministry of Education of China to offer students different options, including full-time and part-time degrees in Bachelor, Master or Ph.D. On-the-job training also has tremendous demand from the professionals who prefer short-term courses or on-site courses. Generally, the development of wind energy education and training lags behind the growth of wind power industry. Our study highlights the major opportunities and future challenges in China wind energy education and training. © 2013 Elsevier Ltd.

Zhang S.,Japan National Institute of Materials Science | Zhang S.,Nanjing University of Science and Technology | Yang X.,Japan National Institute of Materials Science | Qin C.,Japan National Institute of Materials Science | And 3 more authors.
Journal of Materials Chemistry A | Year: 2014

Dye-sensitized solar cells as "low-cost" alternatives to traditional silicon-based solar cells are promising for clean electricity generation. The key processes in practical devices, such as generation, collection, and recombination of charges that greatly affect the cell performance, occur at interfaces and are influenced by properties of the interfacial materials. In this article, we summarize recent progress of materials and technologies associated with the functionalization of interfaces to significantly improve DSCs' performance, emphasizing greatly the most important semiconductor/dye/electrolyte interface where major energy conversion and charge transfer processes occur. Finally, the prospects of interfacial engineering for highly efficient dye-sensitized solar cells are highlighted in the outlook. © 2014 the Partner Organisations.

Xu Z.,Shanghai JiaoTong University | Xu Z.,Nanjing University of Science and Technology | Yager R.R.,The College of New Rochelle
IEEE Transactions on Fuzzy Systems | Year: 2010

The power-average (PA) operator and the power-ordered-weighted-average (POWA) operator are the two nonlinear weighted-average aggregation tools whose weighting vectors depend on the input arguments. In this paper, we develop a power-geometric (PG) operator and its weighted form, which are on the basis of the PA operator and the geometric mean, and develop a power-ordered-geometric (POG) operator and a power-ordered-weighted-geometric (POWG) operator, which are on the basis of the POWA operator and the geometric mean, and study some of their properties. We also discuss the relationship between the PA and PG operators and the relationship between the POWA and POWG operators. Then, we extend the PG and POWG operators to uncertain environments, i.e., develop an uncertain PG (UPG) operator and its weighted form, and an uncertain power-ordered-weighted-geometric (UPOWG) operator to aggregate the input arguments taking the form of interval of numerical values. Furthermore, we utilize the weighted PG and POWG operators, respectively, to develop an approach to group decision making based on multiplicative preference relations and utilize the weighted UPG and UPOWG operators, respectively, to develop an approach to group decision making based on uncertain multiplicative preference relations. Finally, we apply both the developed approaches to broadband Internet-service selection. © 2006 IEEE.

Ma Q.,Nanjing University of Science and Technology | Miao G.,Nanjing University of Information Science and Technology
Neurocomputing | Year: 2014

This paper investigates the distributed containment control problem for linear multi-agent systems. Distributed dynamic output feedback controllers on the basis of the relative outputs of neighboring agents are proposed. Necessary and sufficient containment control conditions are presented which are less conservative than those in the literature. These conditions depend on the spectral properties of the topology matrix. Effective algorithms are proposed to obtain control gain matrices based on H∞ type Riccati design. Then, distributed static output feedback control method is also discussed. Simulation examples are provided finally to demonstrate the effectiveness of the proposed design methods. © 2014 Elsevier B.V.

Xu L.,Nanjing University of Science and Technology | Nallanathan A.,King's College London
IEEE Journal on Selected Areas in Communications | Year: 2016

In this paper, an energy-efficient resource allocation problem is modeled as a chance-constrained programming for multicast cognitive orthogonal frequency division multiplexing (OFDM) network. The resource allocation is subject to constraints in service quality requirements, total power, and probabilistic interference constraint. The statistic channel state information (CSI) between cognitive-based station (CBS) and primary user (PU) is adopted to compute the interference power at the receiver of PU, and we develop an energy-efficient chance-constrained subcarrier and power allocation algorithm. Support vector machine (SVM) is employed to compute the probabilistic interference constraint. Then, the chance-constrained resource allocation problem is transformed into a deterministic resource allocation problem, and Zoutendijk's method of feasible direction is utilized to solve it. Simulation results demonstrate that the proposed algorithm not only achieves a tradeoff between energy efficiency and satisfaction index, but also guarantees the probabilistic interference constraint very well. © 2016 IEEE.

Ge W.,Nanjing University of Science and Technology | Zhu X.,Nanjing University of Science and Technology | Zhu X.,Yancheng Institute of Technology | Wei Y.,Nanjing University of Science and Technology
European Journal of Organic Chemistry | Year: 2013

An aerobic CeCl3·7H2O/NaI-catalyzed C-H functionalization reaction was developed for the synthesis of 3-sulfenylimidazo[1,2-a]pyridines from easily available ketones, 2-aminopyridines, and disulfides without DMSO or peroxide as an oxidant. This three-component tandem reaction process involves the formation of imidazo[1,2-a]pyridines followed by Friedel-Crafts sulfenylation in one pot under mild conditions. Both aryl and alkyl ketones afforded the desired products in good to excellent yields without the presence of other additives. Aerobic oxidative three-component tandem formation of C-N and C-S bonds in one-pot! A CeCl3·7H2O/NaI system is efficient for the synthesis of 3-sulfenylimidazo[1,2-a]pyridines through a C-H functionalization strategy. Without the use of disulfides, a variety of imidazo[1,2-a]pyridines are obtained in good yields by using this protocol. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feng Y.,Nanjing University of Science and Technology | Qiu Y.,Nanjing University of Science and Technology | Crabtree C.J.,Durham University | Long H.,University of Sheffield | Tavner P.J.,Durham University
Wind Energy | Year: 2013

Song G.,Nanjing University of Science and Technology | Wang Z.,Shandong University of Science and Technology | Wang Z.,Nanjing University
Nonlinear Dynamics | Year: 2013

This paper is concerned with the problems of output feedback control for uncertain discrete time-delay systems with input saturation. The delay partitioning approach is proposed to obtain new stability criteria. The dynamic output feedback controller is designed based on a linear matrix inequality framework. A sufficient condition is developed, which guarantees the existence of dynamic output feedback controllers such that all trajectories of the closed-loop system starting from an admissible initial condition domain converge to a smaller ellipsoid. Simulation examples are provided to show the potential of the proposed techniques. © 2013 Springer Science+Business Media Dordrecht.

Hu J.,Zhejiang Ocean University | Li N.,Donghua University | Liu X.,Nanjing University of Science and Technology | Zhang G.,Nanjing University of Science and Technology
Nonlinear Dynamics | Year: 2013

This paper is concerned with the sampled-data state estimation problem for a class of delayed neural networks with Markovian jumping parameters. Unlike the classical state estimation problem, in our state estimation scheme, the sampled measurements are adopted to estimate the concerned neuron states. The neural network under consideration is assumed to have multiple modes that switch from one to another according to a given Markovian chain. By utilizing the input delay approach, the sampling period is converted into a time-varying yet bounded delay. Then a sufficient condition is given under which the resulting error dynamics of the neural networks is exponentially stable in the mean square. Based on that, a set of sampled-data estimators is designed in terms of the solution to a set of linear matrix inequalities (LMIs) which can be solved by using the available software. Finally, a numerical example is used to show the effectiveness of the estimation approach proposed in this paper. © 2013 Springer Science+Business Media Dordrecht.

Li X.-W.,Nanjing Southeast University | Li X.-W.,Nanjing University of Science and Technology | Zhang X.-S.,Nanjing Southeast University | Quan S.,China Wuzhou Engineering Corporation Ltd.
Applied Energy | Year: 2011

Liquid desiccant cooling system (LDCS) is a novel air-conditioning system with good energy saving potential. However, the present LDCS has a poor performance, mainly because the conventional thermal regeneration method wastes too much energy during the regeneration process. To improve that, photovoltaic-electrodialysis (PV-ED) regeneration method is introduced: it has a higher performance by using solar photovoltaic panels to drive an electrodialysis regeneration process. To further explore the PV-ED method, both single-stage and double-stage photovoltaic-electrodialysis regeneration systems are presented in this paper. Analysis is made on these two systems and some influential factors are investigated. It reveals that the concentration difference between the desiccant solution before and after regeneration has a strong impact on system performance. Moreover, comparison is conducted between the single-stage and the double-stage systems, the results show that the double-stage system is more energy-efficient and it can save more than 50% energy under optimized working conditions. © 2011 Elsevier Ltd.

Zhang D.,Linyi Normal University | Zhang D.,Nanjing University of Science and Technology | Yang H.,Linyi Normal University
Journal of Molecular Structure | Year: 2014

In this work, polyvinylpyrrolidone(PVP)-capped silver nanoparticles were synthesized using ethylene glycol as solvent and reducing agent through a simple, one-pot solvothermal method at 160 C. UV-vis spectroscopy, TEM and Raman spectra are used to characterize the PVP-capped silver nanoparticles. The results show that the formed silver nanoparticles are anisotropy with different size and morphology such as triangle, hexagon and pentagon. Moreover, the formation process of silver nanoparticles was discussed in detail. Furthermore, the formed silver nanoparticles displayed high surface-enhanced Raman scattering effects. © 2013 Elsevier B.V. All rights reserved.

Wang Z.,Nanjing University of Science and Technology | Wang Z.,Shandong University of Science and Technology | Huang X.,Shandong University of Science and Technology | Shen H.,Anhui University of Technology
Neurocomputing | Year: 2012

This paper addresses the design of sliding mode controller (SMC) for an uncertain chaotic fractional order economic system. A new fraction-integer integral switching surface is constructed to facilitate stability analysis of the closed-loop system. A sliding mode controller is developed to guarantee that sliding mode motion exists on every point of the switching surface and any state outside the surface is driven to reach the surface in a finite time. Moreover, an adaptive SMC is designed in the case that the upper bound of the uncertainties is unknown. Numerical simulations are performed to verify the feasibility and effectiveness of the proposed controllers. © 2011 Elsevier B.V.

Cheng Q.,Nanjing Southeast University | Zhang X.-S.,Nanjing Southeast University | Li X.-W.,Nanjing Southeast University | Li X.-W.,Nanjing University of Science and Technology
Energy and Buildings | Year: 2012

Photovoltaic-electrodialysis (PV-ED) regeneration is a novel method for liquid desiccant cooling system (LDCS), which has a higher performance than the conventional thermal regeneration method by using solar photovoltaic components to drive an electrodialysis regeneration process. However, there are many defects in the previous proposed single-stage PV-ED system. In this paper, a new double-stage photovoltaic/thermal ED regeneration system is presented. Analysis of the performances of the single-stage and double-stage regeneration system is made and the influential factors are investigated. It reveals that the double-stage PVT-ED regeneration system is more applicable than the single-stage PV-ED regeneration system for liquid desiccant cooling system. Moreover, comparisons between the single-stage system and the double-stage system show that the double-stage system is more energy efficient than the single-stage system under the optimized working conditions. © 2012.

Yin J.,Nanjing University of Science and Technology | Liu Z.,Nanjing University of Science and Technology | Jin Z.,Nanjing University of Science and Technology | Yang W.,Nanjing Southeast University
Neurocomputing | Year: 2012

Sparse representation has attracted great attention in the past few years. Sparse representation based classification (SRC) algorithm was developed and successfully used for classification. In this paper, a kernel sparse representation based classification (KSRC) algorithm is proposed. Samples are mapped into a high dimensional feature space first and then SRC is performed in this new feature space by utilizing kernel trick. Since samples in the high dimensional feature space are unknown, we cannot perform KSRC directly. In order to overcome this difficulty, we give the method to solve the problem of sparse representation in the high dimensional feature space. If an appropriate kernel is selected, in the high dimensional feature space, a test sample is probably represented as the linear combination of training samples of the same class more accurately. Therefore, KSRC has more powerful classification ability than SRC. Experiments of face recognition, palmprint recognition and finger-knuckle-print recognition demonstrate the effectiveness of KSRC. © 2011 Elsevier B.V.

Zuo X.-B.,Nanjing University of Science and Technology | Li A.-Q.,Nanjing Southeast University
Structural Control and Health Monitoring | Year: 2011

This paper estimates the effectiveness of shape memory alloy (SMA) damper on cable vibration mitigation by numerical simulation and experimental investigation. First, a simplified constitutive law of superelastic SMA and the structure of the SMA damper developed by superelastic SMA wires are presented. Second, based on Hamilton principle and Galerkin method, the vibration equations for a cable-SMA damper system are established, and numerical solutions of which are adopted to obtain the dynamic responses of the system without and with SMA damper using the Newmark-β method. Finally, numerical simulation associated with a practical cable and experiments on a scaled test cable are, respectively, carried out to investigate the effectiveness of SMA damper on the vibration mitigation of the cable subjected to the free and forced vibration. Numerical simulations indicate that the SMA damper developed can clearly shorten the free vibration decay time of the cable and increase the equivalent damping ratios of the cable with the reasonable parameter and location of SMA damper, and that it can decrease the displacement response amplitude when the cable is subjected to white-noise excitations. The experimental results show that the SMA damper can reduce the acceleration response of the test cable under free vibration and forced vibration induced by the deck motion. As a result, the SMA damper developed is very effective for mitigating cable vibration. Copyright © 2009 John Wiley & Sons, Ltd.

Huang H.,Rice University | Huang H.,Nanjing University of Science and Technology | Yang S.,Rice University | Yang S.,Beihang University | And 3 more authors.
Advanced Materials | Year: 2014

Homogeneous dispersion of ultrafine Pt nanoparticles on 3D architectures constructed of graphene and exfoliated graphitic carbon nitride results in hybrids with 3D porous structures, large surface area, high nitrogen content, and good electrical conductivity. This leads to excellent electrocatalytic activity, unusually high poison tolerance, and reliable stability for methanol oxidation, making them of interest as catalysts in direct methanol fuel cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ding S.-N.,Nanjing Southeast University | Gao B.-H.,Nanjing Southeast University | Shan D.,Nanjing University of Science and Technology | Sun Y.-M.,Nanjing Southeast University | Cosnier S.,CNRS Molecular Chemistry Department
Biosensors and Bioelectronics | Year: 2013

Electrochemiluminescence (ECL) of TiO 2 nanocrystals with different crystal styles modified fluorine-doped tin oxide (FTO) electrode was investigated in H 2O 2 solution. The amorphous TiO 2 nanospheres were facilely synthesized by the hydrothermal and condensation method. Crystal TiO 2, namely anatase and rutile, were prepared by calcination of the amorphous TiO 2 nanospheres at 450 and 800°C, respectively. The transmission electron microscope (TEM) and electron diffraction pattern were used to characterize the obtained TiO 2 nanoparticles morphology and the corresponding crystal styles. The electrochemical and ECL behaviors were investigated by cyclic voltammetry. The ECL quenching was observed by introduction of gold nanoparticles. Based on the quenching effect, a sensitive glucose ECL biosensor as a model was fabricated by in-situ growing-up gold seeds in AuCl 4 - solution induced by biologically generated H 2O 2. The linear range to detect glucose is from 5.0×10 -7M to 4.0×10 -3M with the limit of detection of 2.5×10 -7M. © 2012 Elsevier B.V..

Chen G.,Nanjing University of Science and Technology | Zhang W.,Nanjing Southeast University
IEEE Transactions on Industrial Electronics | Year: 2016

The paper describes application of unmanned robot applied to automotive test (URAT) to save time, costs, and to improve accuracy of tests. A hierarchical coordinated control method based on fuzzy logic theory is proposed for URAT, to realize the coordinated control and the accurate speed tracking of driving test cycle during all kinds of conditions. The system structure is briefly described in the paper. Similar to a skilled human driver, a control method based on Saridis hierarchical architecture to coordinate multiple robot manipulators systems for the automotive test system is presented. The coordinated movements for throttle mechanical leg, clutch mechanical leg, brake mechanical leg are designed. On top of that, the fuzzy speed controller for URAT is used to accurately track the desired vehicle velocity under different test conditions. Experiments have been conducted by using a Ford FOCUS car. The proposed control method of URAT is experimentally proved and compared with other control methods and with human driver performances. © 1982-2012 IEEE.

Gleiter H.,Karlsruhe Institute of Technology | Gleiter H.,Nanjing University of Science and Technology
Beilstein Journal of Nanotechnology | Year: 2013

Nanoglasses are a new class of noncrystalline solids. They differ from today's glasses due to their microstructure that resembles the microstructure of polycrystals. They consist of regions with a melt-quenched glassy structure connected by interfacial regions, the structure of which is characterized (in comparison to the corresponding melt-quenched glass) by (1) a reduced (up to about 10%) density, (2) a reduced (up to about 20%) number of nearest-neighbor atoms and (3) a different electronic structure. Due to their new kind of atomic and electronic structure, the properties of nanoglasses may be modified by (1) controlling the size of the glassy regions (i.e., the volume fraction of the interfacial regions) and/or (2) by varying their chemical composition. Nanoglasses exhibit new properties, e.g., a Fe90Sc10 nanoglass is (at 300 K) a strong ferromagnet whereas the corresponding melt-quenched glass is paramagnetic. Moreover, nanoglasses were noted to be more ductile, more biocompatible, and catalytically more active than the corresponding melt-quenched glasses. Hence, this new class of noncrystalline materials may open the way to technologies utilizing the new properties. © 2013 Gleiter; licensee Beilstein-Institut.

Zhang D.,Linyi Normal University | Zhang D.,Nanjing University of Science and Technology | Zou W.,Nanjing University of Science and Technology
Current Applied Physics | Year: 2013

In this paper, a composite of reduced graphene oxide decorated by Co 3O4 hollow spheres (Co3O4/RGO composite) has been synthesized by a one-pot solvothermal method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR), Raman spectra and so on. The results demonstrate that the Co3O4 hollow spheres with good purity and homogenous size are absorbed onto the reduced graphene oxide sheets as spacers to prevent the aggregation of the graphene oxide sheets. Furthermore, the well electrochemical properties demonstrate that the Co3O 4/RGO composite might have potential applications as electrode materials for supercapacitors. © 2013 Elsevier Ltd. All rights reserved.

Lin X.,Nanjing Agricultural University | Lin X.,Nanjing University of Science and Technology | Du H.,Nanjing Southeast University | Li S.,Nanjing Southeast University | Zou Y.,Nanjing University of Science and Technology
IET Control Theory and Applications | Year: 2013

Finite-time stability and finite-time boundedness for a class of switched linear systems with time-varying delay are studied. Sufficient conditions which guarantee switched linear systems with time-varying delay finite-time stable or finite-time bounded are presented. These conditions are delay-dependent and are given in terms of linear matrix inequalities. Average dwell time of switching signals is also given such that switched linear systems are finite-time stable or finite-time bounded. Moreover, finite-time weighted L2-gain of switched linear systems with time-varying delay are also given to measure its disturbance tolerance capability in the fixed time interval. Detail proofs are accomplished by using multiple Lyapunov-like functions. An example is employed to verify the efficiency of the proposed method. © 2013 The Institution of Engineering and Technology.

Xu J.,Northwestern Polytechnical University | Xu J.,Nanjing University of Science and Technology | Xu J.,Nanjing Southeast University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2016

This later firstly presents a quasi-elliptic bandpass filter (QE-BPF) which consists of a pair of shorted stepped-impedance resonator (SSIR) and a dual-mode resonator (DMR). Then, a 900 MHz switchable bandpass filter (SW-BPF) and a 1250 MHz SW-BPF are designed by loading p-i-n diodes at two open ends of DMR or SSIRs. Finally, a common-T junction constructed by two T-networks is used to combine the above designed 900 and 1250 MHz SW-BPFs to constitute a switchable diplexer. The fabricated QE-BPF, two SW-BPFs and switchable diplexer exhibit wide bandwidth, low insertion loss, sharp passband selectivity, high port isolation and compact size. © 2015 IEEE.

Yao J.,Nanjing University of Science and Technology | Deng W.,Beihang University | Jiao Z.,Beihang University
IEEE Transactions on Industrial Electronics | Year: 2015

This paper concerns high-accuracy tracking control for hydraulic actuators with nonlinear friction compensation. Typically, LuGre model-based friction compensation has been widely employed in sundry industrial servomechanisms. However, due to the piecewise continuous property, it is difficult to be integrated with backstepping design, which needs the time derivation of the employed friction model. Hence, nonlinear model-based hydraulic control rarely sets foot in friction compensation with nondifferentiable friction models, such as LuGre model, Stribeck effects, although they can give excellent friction description and prediction. In this paper, a novel continuously differentiable nonlinear friction model is first derived by modifying the traditional piecewise continuous LuGre model, then an adaptive backstepping controller is proposed for precise tracking control of hydraulic systems to handle parametric uncertainties along with nonlinear friction compensation. In the formulated nonlinear hydraulic system model, friction parameters, servovalve null shift, and orifice-type internal leakage are all uniformly considered in the proposed controller. The controller theoretically guarantees asymptotic tracking performance in the presence of parametric uncertainties, and the robustness against unconsidered dynamics, as well as external disturbances, is also ensured via Lyapunov analysis. The effectiveness of the proposed controller is demonstrated via comparative experimental results. © 1982-2012 IEEE.

Chen G.,Nanjing University of Science and Technology | Zhang W.-G.,Nanjing Southeast University
Robotics and Computer-Integrated Manufacturing | Year: 2015

The digital prototyping design of electromagnetic unmanned robot applied to automotive test (URAT) is presented in this paper. The electromagnetic URAT adopts electromagnetic linear motor (EMLM) as its drive mechanism. The three-dimensional simulation model of electromagnetic URAT is established. And the kinematics simulation and dynamics simulation of electromagnetic URAT is conducted. The displacement, speed and force of shift mechanical arm, throttle mechanical leg, brake mechanical leg and clutch mechanical leg are obtained. Using the finite element method (FEM), the structure and material of key components of electromagnetic URAT are checked. The automatic driving simulation of electromagnetic URAT is conducted. Experiments are performed using a Ford FOCUS car. Simulation and experiment results demonstrate the effectiveness of the proposed prototyping of electromagnetic URAT system. © 2014 Elsevier Ltd. All rights reserved.

Wang W.,Nanjing University of Science and Technology | Cao Y.,Tianjin Normal University
International Journal of Energy Research | Year: 2013

Chemical-looping ethanol reforming with carbon dioxide capture is proposed. It combines chemical-looping reforming and carbon dioxide capture for pure hydrogen generation from ethanol with inherent separation of carbon dioxide. A thermal analysis of the process using NiO oxygen carrier is performed by simulating reactions using the Gibbs energy minimization method. The promising systems are investigated further with respect to temperature, NiO/C2H5OH molar ratio, CaO/C2H5OH molar ratio and pressure changes as well as possible carbon formation in the reformer. Favorable operation conditions in the presence of CaO are: pressures around 3 atm, reactor temperatures around 850 K, NiO/C2H5OH molar ratio=3 and CaO/C2H5OH=3. The H2 yield and thermal efficiency with CaO addition are higher than that without CaO addition, showing that the addition of a CO2 sorbent in the process increases the H2 production. © 2012 John Wiley & Sons, Ltd.

Yao J.,Nanjing University of Science and Technology | Jiao Z.,Beihang University | Ma D.,Nanjing University of Science and Technology | Yan L.,Beihang University
IEEE/ASME Transactions on Mechatronics | Year: 2014

Structured and unstructured uncertainties are the main obstacles in the development of advanced controllers for high-accuracy tracking control of hydraulic servo systems. For the structured uncertainties, nonlinear adaptive control can be employed to achieve asymptotic tracking performance. But modeling errors, such as nonlinear frictions, always exist in physical hydraulic systems and degrade the tracking accuracy. In this paper, a robust integral of the sign of the error controller and an adaptive controller are synthesized via backstepping method for motion control of a hydraulic rotary actuator. In addition, an experimental internal leakage model of the actuator is built for precise model compensation. The proposed controller accounts for not only the structured uncertainties (i.e., parametric uncertainties), but also the unstructured uncertainties (i.e., nonlinear frictions). Furthermore, the controller theoretically guarantees asymptotic tracking performance in the presence of various uncertainties, which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive comparative experimental results are obtained to verify the high-accuracy tracking performance of the proposed control strategy. © 2013 IEEE.

Yao J.,Nanjing University of Science and Technology | Jiao Z.,Beihang University | Ma D.,Nanjing University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2014

In this paper, an output feedback nonlinear control is proposed for a hydraulic system with mismatched modeling uncertainties in which an extended state observer (ESO) and a nonlinear robust controller are synthesized via the backstepping method. The ESO is designed to estimate not only the unmeasured system states but also the modeling uncertainties. The nonlinear robust controller is designed to stabilize the closed-loop system. The proposed controller accounts for not only the nonlinearities (e.g., nonlinear flow features of servovalve), but also the modeling uncertainties (e.g., parameter derivations and unmodeled dynamics). Furthermore, the controller theoretically guarantees a prescribed tracking transient performance and final tracking accuracy, while achieving asymptotic tracking performance in the absence of time-varying uncertainties, which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive comparative experimental results are obtained to verify the high-performance nature of the proposed control strategy. © 1982-2012 IEEE.

Zuo X.-B.,Nanjing University of Science and Technology | Sun W.,Nanjing Southeast University | Yu C.,Nanjing Southeast University
Construction and Building Materials | Year: 2012

In order to evaluate numerically the volumetric expansion of concrete under sulfate attack, models are proposed to calculate the expansive volume strain of concrete exposed to sulfate solutions. Firstly, a one-dimensional differential equation related to the diffusion-reaction behavior of sulfate ions in concrete is presented; secondly, based on chemical reactions between sulfate and calcium aluminates in concrete, the expansive volume strain caused by ettringite growth is obtained; thirdly, numerical analysis is carried out to investigate the volume expansion of concrete when it is exposed in sulfate solutions. Numerical results provide the evolution response of concrete volume expansion with the diffusion time, sulfate concentration, and calcium aluminates dissipation. © 2012 Elsevier Ltd. All rights reserved.

Yao J.,Nanjing University of Science and Technology | Jiao Z.,Beihang University | Ma D.,Nanjing University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2014

Structured and unstructured uncertainties always exist in physical servo systems and degrade their tracking accuracy. In this paper, a practical method named adaptive robust control with extended state observer (ESO) is synthesized for high-accuracy motion control of a dc motor. The proposed controller accounts for not only the structured uncertainties (i.e., parametric uncertainties) but also the unstructured uncertainties (i.e., nonlinear friction, external disturbances, and/or unmodeled dynamics). Adaptive control for the structured uncertainty and ESO for the unstructured uncertainty are designed for compensating them respectively and integrated together via a feedforward cancellation technique. The global robustness of the controller is guaranteed by a feedback robust law. Furthermore, the controller theoretically guarantees a prescribed tracking performance in the presence of various uncertainties, which is very important for high-accuracy control of motion systems. Extensive comparative experimental results are obtained to verify the high-performance nature of the proposed control strategy. © 1982-2012 IEEE.

Yao J.,Nanjing University of Science and Technology | Jiao Z.,Beihang University | Ma D.,Nanjing University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2014

Continuous friction compensation along with other modeling uncertainties is concerned in this paper, to result in a continuous control input, which is more suitable for controller implementation. To accomplish this control task, a practical method, named as robust integral of the sign of the error controller, is synthesized with a continuous differentiable friction model for high-accuracy motion control of a dc motor. To reduce the noise sensitivity and further improve the tracking accuracy, a desired compensation technique is employed in the proposed controller, in which the model compensation term depends on the reference trajectory only, and its global stability is guaranteed by a proper robust feedback law. Furthermore, the proposed controller theoretically guarantees an asymptotic output tracking performance even in the presence of modeling uncertainties, which is very important for high-accuracy control of motion systems. Comparative experimental results are obtained for the motion control of a dc motor drive system to verify the high-performance nature of the proposed control strategy. © 2014 IEEE.

Wang Z.,Nanjing University of Science and Technology | Wang Z.,Shandong University of Science and Technology | Huang X.,Shandong University of Science and Technology | Shi G.,Changzhou University
Computers and Mathematics with Applications | Year: 2011

In this paper, a delayed fractional order financial system is proposed and the complex dynamical behaviors of such a system are discussed by numerical simulations. A great variety of interesting dynamical behaviors of such a system including single-periodic, multiple-periodic, and chaotic motions are displayed. In particular, the effect of time delay on the chaotic behavior is investigated, it is found that an approximate time delay can enhance or suppress the emergence of chaos. Meanwhile, corresponding to different values of delay, the lowest orders for chaos to exist in the delayed fractional order financial systems are determined, respectively. © 2011 Elsevier Ltd. All rights reserved.

Chen S.,Nanjing University of Science and Technology | Zhu J.,Nanjing University of Science and Technology | Qiu L.,Monash University | Li D.,Monash University | Wang X.,Nanjing University of Science and Technology
Chemistry - A European Journal | Year: 2013

The development of novel nanostructured electrode materials with high performance and based on abundant elements is a key element in the societal pursuit of sustainable energy. Graphene-based structures with rich macroporosity and high conductive networks are promising components to develop novel electrode materials. Herein, we described a facile procedure to confine Ni(OH)2 particles in a graphene film, leading to a new sandwich-like hybrid structure. The hybrid film offers simultaneously ordered ion diffusion channels and high electrical conductivity, which facilitate the improvement of both electrode kinetics and electrochemical stability, thus leading to high capacitance, fast rate capability, and stable cycle life as supercapacitor materials. This work provides a facile pathway for optimized structures for electrode materials, and represents a benefit for the global issues of energy shortage and environmental pollution. Sandwich-like structures: Confinement of Ni(OH)2 particles in a graphene film has resulted in a new sandwich-like structure with excellent electrode kinetics and electrochemical stability. This system is a promising candidate for supercapacitor materials (see figure). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xu Z.,Nanjing Southeast University | Xu Z.,Nanjing University of Science and Technology
IEEE Transactions on Fuzzy Systems | Year: 2012

We investigate multiattribute decision-making problems, where the attribute values are intuitionistic fuzzy values, and the weight information on attributes cannot be known completely. We first define the concepts of the overall attribute ideal solution and the overall attribute negative ideal solution of alternatives. Based on these two solutions, we define the satisfaction degree of each alternative. After that, we establish a multiobjective optimization model and then transform it into a single-objective optimization model. Furthermore, we establish an interactive method for multiattribute decision making with intuitionistic fuzzy information. A numerical example is also given to illustrate the solution processes of our methods. Finally, the extended results in interval-valued intuitionistic fuzzy situations are also pointed out. © 2012 IEEE.

Zheng L.,Nanjing University of Science and Technology | Zheng S.,Zhejiang University of Finance and Economics | Zhai Q.,Chaohu University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2015

In this paper a lattice Boltzmann equation (LBE) method is designed that is different from the previous LBE for the Cahn-Hilliard equation (CHE). The starting point of the present CHE LBE model is from the kinetic theory and the work of Lee and Liu [T. Lee and L. Liu, J. Comput. Phys. 229, 8045 (2010)JCTPAH0021-999110.1016/j.jcp.2010.07.007]; however, because the CHE does not conserve the mass locally, a modified equilibrium density distribution function is introduced to treat the diffusion term in the CHE. Numerical simulations including layered Poiseuille flow, static droplet, and Rayleigh-Taylor instability have been conducted to validate the model. The results show that the predictions of the present LBE agree well with the analytical solution and other numerical results. © 2015 American Physical Society.

Li X.-W.,Nanjing University of Science and Technology | Li X.-W.,Nanjing Southeast University | Zhang X.-S.,Nanjing Southeast University
Energy Conversion and Management | Year: 2012

Absorption air-conditioning system has many priorities over vapor compression air-conditioning system as absorption system is more environment-friendly, capable of utilizing low grade heat and less dependent on the electric power. However, because of the low efficiency of energy usage, the performance of absorption system is not yet as competitive as vapor compression system. To improve that, a novel membrane absorption system is proposed in this paper: a regenerator consists of stacks with ion-exchange membranes, takes the places of the generator and the condenser; the electric energy gained from solar or wind power is utilized to drive this system. Primary analysis has been made, and the results show that this proposed membrane absorption air-conditioning system can raise its coefficient of performance as high as, or even higher than that of vapor compression system when the absorbent is LiBr solution, of which the mass concentration is below 52%, and the applied voltage is no more than 100 V. © 2011 Elsevier Ltd. All rights reserved.

Yao J.,Nanjing University of Science and Technology | Jiao Z.,Beihang University | Han S.,Beihang University
Chinese Journal of Aeronautics | Year: 2013

Low-velocity tracking capability is a key performance of flight motion simulator (FMS), which is mainly affected by the nonlinear friction force. Though many compensation schemes with ad hoc friction models have been proposed, this paper deals with low-velocity control without friction model, since it is easy to be implemented in practice. Firstly, a nonlinear model of the FMS middle frame, which is driven by a hydraulic rotary actuator, is built. Noting that in the low velocity region, the unmodeled friction force is mainly characterized by a changing-slowly part, thus a simple adaptive law can be employed to learn this changing-slowly part and compensate it. To guarantee the boundedness of adaptation process, a discontinuous projection is utilized and then a robust scheme is proposed. The controller achieves a prescribed output tracking transient performance and final tracking accuracy in general while obtaining asymptotic output tracking in the absence of modeling errors. In addition, a saturated projection adaptive scheme is proposed to improve the globally learning capability when the velocity becomes large, which might make the previous proposed projection-based adaptive law be unstable. Theoretical and extensive experimental results are obtained to verify the high-performance nature of the proposed adaptive robust control strategy. © 2013 Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.

Li X.-W.,Nanjing University of Science and Technology | Li X.-W.,Nanjing Southeast University | Zhang X.-S.,Nanjing Southeast University | Wang F.,Nanjing University of Science and Technology
Energy and Buildings | Year: 2013

Liquid desiccant cooling system (LDCS) is an alternative air-conditioning system with promising energy-saving potential. To further explore the potential of LDCS, it is important to reveal the mass transfer mechanism of dehumidification process. The classical mass transfer model does well in theoretical analysis, but failed to explain the dehumidification reverse phenomenon in experiments. Therefore, this paper proposes a mass transfer model based on the kinetic theory for improvement. Through theoretical and experimental research, it proves the new model clearly describes the dehumidification mechanism and did better in predicting the dehumidification reverse phenomenon. This paper also gives a method through which we can get some important parameters of the new model from the mass transfer coefficient of the classical model. © 2013 Elsevier B.V.

Ding S.-N.,Nanjing Southeast University | Shan D.,Nanjing University of Science and Technology | Cosnier S.,CNRS Molecular Chemistry Department | Le Goff A.,CNRS Molecular Chemistry Department
Chemistry - A European Journal | Year: 2012

Ru being served: A pyrene-Ru/SWCNT nanohybrid was formed through noncovalent π-π stacking interactions (see figure). After oxidative treatment, the pyrene-Ru/SWCNT-functionalized Pt electrode achieved a highly reversible redox process and exhibited excellent electrogenerated chemiluminescence behavior. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ding S.-N.,Nanjing Southeast University | Gao B.-H.,Nanjing Southeast University | Shan D.,Nanjing University of Science and Technology | Sun Y.-M.,Nanjing Southeast University | Cosnier S.,CNRS Molecular Chemistry Department
Chemistry - A European Journal | Year: 2012

Shining brightly: Several tens to hundreds of times enhanced solid-state electrochemiluminescence (ECL) of CdTe quantum dots (CdTe-QDs) was realized by combining them with TiO 2 nanoparticles. The mechanism was due to the synergetic effect between titania and CdTe-QDs during the ECL process in H 2O 2 solution (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiong G.,Nanjing University of Science and Technology | Zhang S.,Nanjing University of Science and Technology | Liu Q.,Air Defense Forces Academy
Physica A: Statistical Mechanics and its Applications | Year: 2012

Although the multifractal singularity spectrum revealed the distribution of singularity exponent, it failed to consider the temporal information, therefore it is hard to describe the dynamic evolving process of non-stationary and nonlinear systems. In this paper, we aim for a multifractal analysis and propose a time-singularity multifractal spectrum distribution (TS-MFSD), which will hopefully reveal the spatial dynamic character of fractal systems. Similar to the Wigner-Ville time-frequency distribution, the time-delayed conjugation of fractal signals is selected as the windows function. Furthermore, the time-varying Holder exponent and the time-varying wavelet singularity exponent are deduced based on the instantaneous self-correlation fractal signal. The time-singularity exponent distribution i.e. TS-MFSD is proposed, which involves time-varying Hausdorff singularity spectrum distribution, time-varying large deviation multifractal spectrum and time-varying Legendre spectrum distribution, which exhibit the singularity exponent distribution of fractal signal at arbitrary time. Finally, we studied the algorithm of the TS-MFSD based on the wavelet transform module maxima method, analyzed and discussed the characteristic of TS-MFSD based on Devil Staircase signal, stochastic fractional motion and real sea clutter. © 2012 Elsevier B.V. All rights reserved.

News Article | February 15, 2017
Site: phys.org

Ellipsoid plot of (N5)6(H3O)3(NH4)4Cl at the 50% probability level. The occupancies of H3O+ (O1), H3O+ (O2), Clˉ, N5ˉ, and NH4+ are 1/12, 1/24, 1/24, 1/4, and 1/6, respectively. Credit: (c) Science (2017). DOI: 10.1126/science.aah3840 (Phys.org)—The pentazole molecule and its anion, cyclo-N - has proven elusive to researchers for almost a century. The pentazole anion is highly unstable and cannot be made in bulk. Researchers from Nanjing University of Science and Technology and the University of Science and Technology Liaoning have devised a synthesis of a salt containing the pentazole anion that is stable up to 117oC. Their report appears in Science. The pentazole and its anion have a sordid history, at least for molecules. Pentazole was thought to be isolated as an arylpentazole in 1915, but was disproven several years later. Then, in the 1950s, a group of researchers managed to identify pentazole as an intermediate for another reaction. Later researchers became interested in combining N + and N - as a possible alternative to hydrazine as rocket fuel. Many attempts have been made to isolate the pentazole anion by cleaving the carbon-nitrogen bond in an arylpentazole. However, these have proven unsuccessful because of the difficulties in selectively cleaving the carbon-nitrogen bond. The addition of electron donating groups at the ortho and para positions of the arene helped with selective cleavage. In the current study, Zhang et al. were able to selectively cleave the carbon-nitrogen bond of 3,5-dimethyl-4-hydroxyphenylpentazole and stabilize the resulting pentazole anion using ferrous bisglycinate, Fe(Gly) . The anion was isolated as part of a salt, (N ) (H O) (NH ) Cl (19% yield). The Fe(Gly) stabilizer also served as a mediator for m-chloroperbenzoic acid. The molecular conformation of the salt ions was determined using single-crystal x-ray diffraction analysis where the five nitrogen atoms in cylco-N - are co-planar and aromatic. The structure was confirmed using 1H and 15N NMR as well as infrared and Raman spectroscopy. Additional studies showed that the salt is remarkably thermally stable up to 117oC, which is attributed to the salt's hydrogen bonding arrangement. All of the ions in the salt apparently play a role in stabilizing the pentazole anion. When Zhang et al. removed Cl- or when they removed NH +, cyclo-N - decomposed. This research allows for the isolation and characterization of an elusive aromatic azole molecule, one that has been out of reach for chemists for many years, and according to the authors this ends the search for this elusive molecule. More information: Chong Zhang et al. Synthesis and characterization of the pentazolate anion-Nˉ in (N)(HO)(NH)Cl, Science (2017). DOI: 10.1126/science.aah3840 Abstract Pentazole (HN5), an unstable molecular ring comprising five nitrogen atoms, has been of great interest to researchers for the better part of a century. We report the synthesis and characterization of the pentazolate anion stabilized in a (N5)6(H3O)3(NH4)4Cl salt. The anion was generated by direct cleavage of the C–N bond in a multisubstituted arylpentazole using m-chloroperbenzoic acid and ferrous bisglycinate. The structure was confirmed by single-crystal x-ray diffraction analysis, which highlighted stabilization of the cyclo-N5ˉ ring by chloride, ammonium, and hydronium. Thermal analysis indicated the stability of the salt below 117°C on the basis of thermogravimetry-measured onset decomposition temperature.

Huang H.W.,CAS Shenyang Institute of Metal Research | Wang Z.B.,CAS Shenyang Institute of Metal Research | Lu J.,City University of Hong Kong | Lu K.,CAS Shenyang Institute of Metal Research | Lu K.,Nanjing University of Science and Technology
Acta Materialia | Year: 2015

By means of surface mechanical rolling treatment (SMRT), a gradient nanostructured (GNS) surface layer was formed on AISI 316L stainless steel. The mean grain size is ∼30 nm in the topmost surface layer and increases with depth. Tension-compression fatigue measurements were performed on the SMRT sample under the stress-controlled mode. In comparison with the coarse-grained sample, the fatigue strength of the SMRT sample is significantly enhanced in both the low- and high- cycling fatigue regimes. Meanwhile, the fatigue ratio is evidently elevated with an increasing tensile strength in the SMRT sample. The initiation and growth of cracks, the cyclic deformation behaviors, as well as effects of strength and residual stresses, have been investigated to clarify the fatigue mechanism of the SMRT sample. The results emphasized the GNS surface layer enhances the fatigue property by suppressing the initiation of cracks and accommodating a remarkable cyclic plastic strain amplitude. © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Rong G.,Nanjing University of Science and Technology | Huang D.W.,Shenyang Ligong University | Yang M.C.,CAS Shenyang Institute of Metal Research
Theoretical and Applied Fracture Mechanics | Year: 2012

Ballistic tests are performed by shooting both tungsten fiber/bulk metallic glass W/Zr 58Ti 13Cu 17Ni 12 composite rods (composite rod) and tungsten heavy alloy rods (95W rod) into 30CrMnMo target. The composite rod exhibits self-sharpening behaviors, and its matrix damages and fibers break are limited in a thin, narrow area, which is defined as " edge layer" Penetrating depth of composite rods is 50% deeper than the depth of 95W rods with same dimension size. © 2012 Elsevier Ltd.

Zhou Q.,University of Portsmouth | Zhou Q.,Nanjing University of Science and Technology | Shi P.,University of South Wales | Shi P.,Victoria University of Melbourne | And 2 more authors.
IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics | Year: 2012

This paper focuses on the problem of neural-network-based decentralized adaptive output-feedback control for a class of nonlinear strict-feedback large-scale stochastic systems. The dynamic surface control technique is used to avoid the explosion of computational complexity in the backstepping design process. A novel direct adaptive neural network approximation method is proposed to approximate the unknown and desired control input signals instead of the unknown nonlinear functions. It is shown that the designed controller can guarantee all the signals in the closed-loop system to be semiglobally uniformly ultimately bounded in a mean square. Simulation results are provided to demonstrate the effectiveness of the developed control design approach. © 1996-2012 IEEE.

Liu M.,Qingdao University of Science and Technology | Zhang J.,Qingdao University of Science and Technology | Liu J.,Nanjing University of Science and Technology | Yu W.W.,Jilin University
Journal of Catalysis | Year: 2011

Stable poly(N-vinyl-2-pyrrolidone)-stabilized Pt/Ru colloidal nanoparticles (PVP-Pt/Ru) were prepared via ethanol reduction of H2PtCl 66H2O and RuCl3nH2O. The average diameters of the nanoparticles with different molar ratio of Pt/Ru were in a range of 2.1-2.8 nm with narrow size distributions. X-ray photoelectron spectroscopy verified that both Pt and Ru were in the metallic state and Ru was rich on the surface. These nanoparticles were employed to selectively hydrogenate ortho-chloronitrobenzene at 298 K and 0.1 MPa hydrogen pressure. They showed high activity [TOF was in the range of 0.8-5.3 × 10 -2 molo-CNB/(molM,surface atom) s] and high selectivity (93-99%) to ortho-chloroaniline (o-CAN) for the reaction, which were composition-dependent. The selectivity to o-CAN monotonously increased, but the activity of the catalyst decreased with the increasing proportion of Ru in Pt/Ru colloidal catalysts. PVP-1Pt/4Ru nanoparticles exhibited the highest selectivity of 99.0% to o-CAN at a complete conversion. © 2010 Elsevier Inc. All rights reserved.

Zhou Q.,Nanjing University of Science and Technology | Shi P.,University of South Wales | Shi P.,Victoria University of Melbourne
International Journal of Robust and Nonlinear Control | Year: 2012

This paper deals with the problem of network-based H ∞ control for a class of uncertain stochastic systems with both network-induced delays and packet dropouts. The networked control system under consideration is represented by a stochastic model, which consists of two successive delay components in the state. The uncertainties are assumed to be time varying and norm bounded. Sufficient conditions for the existence of H ∞ controller are proposed to ensure exponentially stable in mean square of the closed-loop system that also satisfies a prescribed performance. The conditions are expressed in the frame of linear matrix inequalities (LMIs), which can be verified easily by means of standard software. Two practical examples are provided to show the effectiveness of the proposed techniques. Copyright © 2011 John Wiley & Sons, Ltd.

Zhang P.,Nanjing University of Science and Technology | Zhang P.,Guilin University of Electronic Technology | Li Q.,Nanjing University of Science and Technology | Xuan Y.,Nanjing University of Science and Technology
Composites Part A: Applied Science and Manufacturing | Year: 2014

To enhance heat transfer performance of epoxy resin as a thermal interface material (TIM), multi-walled carbon nanotubes (MWCNTs) and nano-copper particles are incorporated into an epoxy resin to form hybrid composites. The total thermal contact resistance (TCR) between the heated and cooled surfaces as well as its components such as the bulk resistance (RBLT) of the TIM, and the boundary resistance (RB) between the TIM and the joint surfaces above and below the TIM of the composites are measured. The influence of the compound in different proportions of MWCNTs and nano-copper particles on R BLT and RB is discussed in detail. The results indicate that the total TCR is related not only to the thermal conductivity of the TIM, but also to the other factors such as the property of the filler, the microstructural characterization, and the surface morphology of the TIM.© 2013 Elsevier Ltd. All rights reserved.

Greenbaum A.,University of California at Los Angeles | Luo W.,University of California at Los Angeles | Su T.-W.,University of California at Los Angeles | Gorocs Z.,University of California at Los Angeles | And 6 more authors.
Nature Methods | Year: 2012

We discuss unique features of lens-free computational imaging tools and report some of their emerging results for wide-field on-chip microscopy, such as the achievement of a numerical aperture (NA) of ∼0.8-0.9 across a field of view (FOV) of more than 20 mm2 or an NA of ∼0.1 across a FOV of ∼18 cm2, which corresponds to an image with more than 1.5 gigapixels. We also discuss the current challenges that these computational on-chip microscopes face, shedding light on their future directions and applications. © 2012 Nature America, Inc. All rights reserved.

Che Y.,Nanjing University of Science and Technology | Benson B.L.,Florida State University
Journal of Drug Issues | Year: 2014

Decision making in the face of risk from law enforcement is considered from the perspective provided by theoretical models of interdependent decisions of potential drug smugglers regarding entry and the use of violence following entry. Implications of three different models of decision making under risk are examined: expected value, expected utility, and prospect theory. The theoretical results help explain many observed characteristics of drug-smuggling operations and allow clarification of some implications drawn from studies of smuggling behavior that were not considered in the context of such models. © The Author(s) 2013.

Li Z.,Nanjing University of Science and Technology | Liu J.,CAS Institute of Automation | Yang Y.,Queensland University of Technology | Zhou X.,CAS Institute of Automation | Lu H.,CAS Institute of Automation
IEEE Transactions on Knowledge and Data Engineering | Year: 2014

Many pattern analysis and data mining problems have witnessed high-dimensional data represented by a large number of features, which are often redundant and noisy. Feature selection is one main technique for dimensionality reduction that involves identifying a subset of the most useful features. In this paper, a novel unsupervised feature selection algorithm, named clustering-guided sparse structural learning (CGSSL), is proposed by integrating cluster analysis and sparse structural analysis into a joint framework and experimentally evaluated. Nonnegative spectral clustering is developed to learn more accurate cluster labels of the input samples, which guide feature selection simultaneously. Meanwhile, the cluster labels are also predicted by exploiting the hidden structure shared by different features, which can uncover feature correlations to make the results more reliable. Row-wise sparse models are leveraged to make the proposed model suitable for feature selection. To optimize the proposed formulation, we propose an efficient iterative algorithm. Finally, extensive experiments are conducted on 12 diverse benchmarks, including face data, handwritten digit data, document data, and biomedical data. The encouraging experimental results in comparison with several representative algorithms and the theoretical analysis demonstrate the efficiency and effectiveness of the proposed algorithm for feature selection. © 1989-2012 IEEE.

Zhang L.,Nanjing University of Science and Technology | Sun K.,Tsinghua University | Xing Y.,Nanjing University of Science and Technology | Feng L.,Nanjing University of Science and Technology | Ge H.,Nanjing University of Science and Technology
IEEE Transactions on Power Electronics | Year: 2011

In order to enhance the efficiency and reliability for distributed microgeneration, a modular grid-connected photovoltaic (PV) generation system is proposed. It consists of modular dc-dc converters and modular dc-ac inverters. The outputs of dcdc converter and the inputs of dc-ac inverter share a dc bus. AC current coupling between the parallel-operated inverters, which is the key issue in this generation system, has been investigated. A current-decoupling method is proposed and implemented by regulating the currents of split-filter inductors, respectively. An optimal control strategy for the efficiency enhancement of PV generation system is proposed by utilizing the dispersion of control parameters. During power generation, only one modular dc-ac inverter is operating with nonfull load, and the other modular dc-ac inverters are operating with full load or at standby mode. A prototype of this modularized grid-connected PV generation system is implemented. The steady state and dynamic experimental results show that the fundamental components of two split-filter inductor currents in one inverter module are equivalent, which are decoupled completely, and only one inverter module operates with nonfull load among the parallel-operated inverter modules. The feasibility of the proposed system and the effectiveness of the control strategies have been verified by experimental results. © 2006 IEEE.

Zhou Q.,Nanjing University of Science and Technology | Zhou Q.,Victoria University of Melbourne | Shi P.,Victoria University of Melbourne | Shi P.,University of South Wales | And 2 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2011

This paper is concerned with the problem of adaptive fuzzy tracking control via output feedback for a class of uncertain single-input single-output (SISO) strict-feedback nonlinear systems. The dynamic feedback strategy begins with an input-driven filter. By utilizing fuzzy logic systems to approximate unknown and desired control input signals directly instead of the unknown nonlinear functions, an output-feedback fuzzy tracking controller is designed via a backstepping approach. It is shown that the proposed fuzzy adaptive output controller can guarantee that all the signals remain bounded and that the tracking error converges to a small neighborhood of the origin. Simulations results are presented to demonstrate the effectiveness of the proposed methods. © 2011 IEEE.

Ren Y.-M.,Anhui Polytechnic University | Cai C.,Nanjing University of Science and Technology | Yang R.-C.,Anhui Polytechnic University
RSC Advances | Year: 2013

The multicomponent reactions (MCRs) consist of two or more synthetic steps which are carried out without isolation of any intermediate thus reducing time, saving money, energy and raw materials. The development of MCRs in the presence of molecular iodine is an efficient approach that meets with the requirements of sustainable chemistry. The aim of this review is to highlight the synergistic effect of the combined use of MCRs and molecular iodine for the development of new eco-compatible methodologies for organic chemistry. © The Royal Society of Chemistry 2013.

Fang T.H.,CAS Shenyang Institute of Metal Research | Tao N.R.,CAS Shenyang Institute of Metal Research | Lu K.,CAS Shenyang Institute of Metal Research | Lu K.,Nanjing University of Science and Technology
Scripta Materialia | Year: 2014

With surface mechanical grinding treatment, a gradient nanograined (GNG) surface layer is produced on a bulk coarse-grained (CG) pure Cu, where the grain size increases gradually from 20 nm (topmost surface) to micrometer scale. Microhardness measurements of the GNG/CG sample after tension revealed that tension induces softening for grains smaller than 165 nm and induces hardening above this size. This critical size agrees with the strain-induced saturation grain size of Cu subjected to severe plastic deformation. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Cao J.,Nanjing University of Finance and Economics | Wu Z.,Nanjing University of Finance and Economics | Wang Y.,Nanjing University of Science and Technology | Zhuang Y.,Zhejiang GongShang University
Knowledge and Information Systems | Year: 2013

Web service recommendation has become a hot yet fundamental research topic in service computing. The most popular technique is the Collaborative Filtering (CF) based on a user-item matrix. However, it cannot well capture the relationship between Web services and providers. To address this issue, we first design a cube model to explicitly describe the relationship among providers, consumers and Web services. And then, we present a Standard Deviation based Hybrid Collaborative Filtering (SD-HCF) for Web Service Recommendation (WSRec) and an Inverse consumer Frequency based User Collaborative Filtering (IF-UCF) for Potential Consumers Recommendation (PCRec). Finally, the decision-making process of bidirectional recommendation is provided for both providers and consumers. Sets of experiments are conducted on real-world data provided by Planet-Lab. In the experiment phase, we show how the parameters of SD-HCF impact on the prediction quality as well as demonstrate that the SD-HCF is much better than extant methods on recommendation quality, including the CF based on user, the CF based on item and general HCF. Experimental comparison between IF-UCF and UCF indicates the effectiveness of adding inverse consumer frequency to UCF. © 2012 Springer-Verlag London.

Xu D.,Nanjing University of Science and Technology | Ugrinovskii V.,Tech Force
Systems and Control Letters | Year: 2013

This paper studies the problem of decentralized measurement feedback stabilization of nonlinear interconnected systems. As a natural extension of the recent development on control vector Lyapunov functions, the notion of output control vector Lyapunov function (OCVLF) is introduced for investigating decentralized measurement feedback stabilization problems. Sufficient conditions on (local) stabilizability are discussed which are based on the proposed notion of OCVLF. It is shown that a decentralized controller for a nonlinear interconnected system can be constructed using these conditions under an additional vector dissipation-like condition. To illustrate the proposed method, two examples are given. © 2013 Elsevier B.V. All rights reserved.

Zhang J.-K.,McMaster University | Huang F.,Nanjing University of Science and Technology | Ma S.,University of Jinan
IEEE Transactions on Information Theory | Year: 2011

In this paper, the systematic design of a space-time block code is considered for a wireless communication system with multiple transmitter-receiver antennas and flat fading, in which channel state information is completely unknown. From the viewpoint of blind signal processing, a necessary and sufficient condition is given for the unique identification of the multi-input multi-output flat fading channel and transmitted signal. Then, some novel unique factorizations for a pair of coprime P-ary and Q-ary phase shift keying (PSK) constellations are established. With this and currently available coherent space-time block code designs, a method is developed to systematically construct full diversity blind nonunitary space-time block codes as well as unitary codes by just performing the QR decomposition of the nonunitary codes. It is proved that under a noise-free environment, the code design proposed in this paper can guarantee that the transmitted signals and the channel coefficients are uniquely identified, and that under a complex Gaussian noise environment in which Pth-order and Q th-order statistics (P and Q are co-prime) of the received signals are available, the channel coefficients can be still uniquely identified. In addition, a closed-form solution to determine the channel coefficients is obtained. © 2011 IEEE.

Li H.,Harbin Institute of Technology | Li H.,University of Portsmouth | Zhou Q.,Nanjing University of Science and Technology | Chen B.,Qingdao University | Liu H.,University of Portsmouth
Journal of the Franklin Institute | Year: 2011

In this paper, the problem of parameter-dependent robust stability analysis is addressed for uncertain Markovian jump linear systems (MJLSs) with polytopic parameter uncertainties and time-varying delay. By constructing parameter-dependent Lyapunov functional, some sufficient conditions are developed to enable robust exponential mean square stability for the systems. New parameter-dependent robust stability criteria for MJLSs are established in the form of linear matrix inequalities (LMIs), which can be solved efficiently by the interior-point algorithm. Finally, a numerical example is given to demonstrate the effectiveness of the proposed approach. © 2011 The Franklin Institute © 2011 Published by Elsevier Ltd. on behalf of The Franklin Institute.

Mao J.-R.,Nanjing University of Science and Technology | Mao J.-R.,Aviation Industry Corporation of China | Choi W.-W.,Macau University of Science and Technology | Tam K.-W.,Macau University of Science and Technology | And 2 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2013

In this paper, a tunable bandpass filter using crossshaped multiple mode resonators (MMRs) and transformer based external quality factor tuning structures is proposed. The use of a cross-shaped MMR simplifies inter-resonators control while two tuning structures are investigated and incorporated with theMMR to implement simultaneous center frequency agility and narrow and wide bandwidth tuning. Compared with traditional tunable filters, the proposed architecture requires less tuning elements and is easier to realize wideband and high-order tunable filters. Two examples (Filter I and II) are presented to validate the design. Both filters use a single MMR and six tuning elements to achieve a third-order wideband tunable filter. Filter I reports 58% center frequency tuning with constant bandwidth and 14%-64.4% fractional bandwidth (FBW) tuning when center frequency locates at 1 GHz. Filter II achieves larger frequency agility and wider FBW tuning of 82.9% and 95%, respectively, for the same bandwidth and center frequency of Filter I. © 2013 IEEE.

Zhao Y.,City College of New York | Zhao Y.,Nanjing University of Science and Technology | Seredych M.,City College of New York | Zhong Q.,Nanjing University of Science and Technology | Bandosz T.J.,City College of New York
ACS Applied Materials and Interfaces | Year: 2013

New composites Cu-BTC MOF and graphite oxide modified with urea (GO-U) are developed and tested as CO2 adsorbents at room temperature. The composite containing GO-U with the highest nitrogen content exhibits an excellent CO2 uptake (4.23 mmol/g) at dynamic conditions. The incorporation of GO-U into MOF changes the chemistry and microstructure of the parent MOF and results in synergistic features beneficial for CO2 retention on the surface. To identify these features the initial and exhausted materials were extensively characterized from the points of view of their porosity and chemistry. Although the adsorption forces are relatively strong, the results indicate that CO2 is mainly physisorbed on the composites at dry dynamic conditions at ambient temperature and pressure. The primary adsorption sites include small micropores specific for the composites, open Cu sites, and cage window sites. © 2013 American Chemical Society.

Lu G.-F.,Nanjing University of Science and Technology | Lu G.-F.,Anhui Science and Technology University | Lin Z.,Nanjing University of Science and Technology | Jin Z.,Nanjing University of Science and Technology
Pattern Recognition | Year: 2010

In this paper, we propose a new discriminant locality preserving projections based on maximum margin criterion (DLPP/MMC). DLPP/MMC seeks to maximize the difference, rather than the ratio, between the locality preserving between-class scatter and locality preserving within-class scatter. DLPP/MMC is theoretically elegant and can derive its discriminant vectors from both the range of the locality preserving between-class scatter and the range space of locality preserving within-class scatter. DLPP/MMC can also derive its discriminant vectors from the null space of locality preserving within-class scatter when the parameter of DLPP/MMC approaches +∞. Experiments on the ORL, Yale, FERET, and PIE face databases show the effectiveness of the proposed DLPP/MMC. © 2010 Elsevier Ltd. All rights reserved.

Xu X.,Nanjing University of Science and Technology | Wang J.,Nanjing University of Science and Technology | Zhu L.,Macau University of Science and Technology
IEEE Microwave and Wireless Components Letters | Year: 2013

A new approach to design differential-mode (DM) bandpass filters is proposed and implemented based on the substrate integrated waveguide (SIW) technology. By properly constructing the topologies of SIW resonant cavities, the balanced section of the proposed filter achieves an attractive capacity in simultaneously realizing the desired DM transmission and expected common-mode (CM) suppression in a certain band. In design, the specified DM frequency response is achieved with an equivalent two-port circuit model. To illustrate the possibilities of the new approach, a fourth-order Ku-band prototype is designed and fabricated on a single-layer substrate. Measured results agree well with the predicted counterparts. © 2013 IEEE.

Qiu J.,Harbin Institute of Technology | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Gao H.,Harbin Institute of Technology
IEEE Transactions on Fuzzy Systems | Year: 2012

This paper is concerned with the problem of robust ${\mathscr H}infty output feedback control for a class of continuous-time Takagi-Sugeno (T-S) fuzzy affine dynamic systems using quantized measurements. The objective is to design a suitable observer-based dynamic output feedback controller that guarantees the global stability of the resulting closed-loop fuzzy system with a prescribed${\mathscr H}\infty disturbance attenuation level. Based on common/piecewise quadratic Lyapunov functions combined with S-procedure and some matrix inequality convexification techniques, some new results are developed to the controller synthesis for the underlying continuous-time T-S fuzzy affine systems with unmeasurable premise variables. All the solutions to the problem are formulated in the form of linear matrix inequalities (LMIs). Finally, two simulation examples are provided to illustrate the advantages of the proposed approaches. © 1993-2012 IEEE.

Xu Y.,Harbin Institute of Technology | Zhang D.,Harbin Institute of Technology | Zhang D.,Hong Kong Polytechnic University | Yang J.-Y.,Nanjing University of Science and Technology
Pattern Recognition | Year: 2010

Bimodal biometrics has been found to outperform single biometrics and are usually implemented using the matching score level or decision level fusion, though this fusion will enable less information of bimodal biometric traits to be exploited for personal authentication than fusion at the feature level. This paper proposes matrix-based complex PCA (MCPCA), a feature level fusion method for bimodal biometrics that uses a complex matrix to denote two biometric traits from one subject. The method respectively takes the two images from two biometric traits of a subject as the real part and imaginary part of a complex matrix. MCPCA applies a novel and mathematically tractable algorithm for extracting features directly from complex matrices. We also show that MCPCA has a sound theoretical foundation and the previous matrix-based PCA technique, two-dimensional PCA (2DPCA), is only one special form of the proposed method. On the other hand, the features extracted by the developed method may have a large number of data items (each real number in the obtained features is called one data item). In order to obtain features with a small number of data items, we have devised a two-step feature extraction scheme. Our experiments show that the proposed two-step feature extraction scheme can achieve a higher classification accuracy than the 2DPCA and PCA techniques. © 2009 Elsevier Ltd. All rights reserved.

Xu Y.,Harbin Institute of Technology | Zhong A.,Harbin Institute of Technology | Yang J.,Nanjing University of Science and Technology | Zhang D.,Hong Kong Polytechnic University
Pattern Recognition | Year: 2010

Locality preserving projection (LPP) is a manifold learning method widely used in pattern recognition and computer vision. The face recognition application of LPP is known to suffer from a number of problems including the small sample size (SSS) problem, the fact that it might produce statistically identical transform results for neighboring samples, and that its classification performance seems to be heavily influenced by its parameters. In this paper, we propose three novel solution schemes for LPP. Experimental results also show that the proposed LPP solution scheme is able to classify much more accurately than conventional LPP and to obtain a classification performance that is only little influenced by the definition of neighbor samples. © 2010 Elsevier Ltd. ALL rights reserved.

Yong X.,Harbin Institute of Technology | Zhang D.,Hong Kong Polytechnic University | Yang J.,Nanjing University of Science and Technology | Zhong J.,Nanjing University of Science and Technology
International Journal of Information Technology and Decision Making | Year: 2011

Since in the feature space the eigenvector is a linear combination of all the samples from the training sample set, the computational efficiency of KPCA-based feature extraction falls as the training sample set grows. In this paper, we propose a novel KPCA-based feature extraction method that assumes that an eigenvector can be expressed approximately as a linear combination of a subset of the training sample set ("nodes"). The new method selects maximally dissimilar samples as nodes. This allows the eigenvector to contain the maximum amount of information of the training sample set. By using the distance metric of training samples in the feature space to evaluate their dissimilarity, we devised a very simple and quite efficient algorithm to identify the nodes and to produce the sparse KPCA. The experimental result shows that the proposed method also obtains a high classification accuracy. © 2011 World Scientific Publishing Company.

Zhang C.,City University of Hong Kong | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Qiu J.,City University of Hong Kong | And 2 more authors.
IEEE Transactions on Industrial Electronics | Year: 2013

This paper investigates the controller design for a class of linear network-based systems with communication constraints on both uplink and downlink channels, where the network-induced transmission time delay, packet dropouts, and signal quantization are considered simultaneously. To deal with the phenomenon of quantization, a novel approach is adopted, which converts the quantized state and control signal into a kind of actuator saturation with bounded disturbances. Based on a proposed Lyapunov-Krasovskii functional, the existence conditions of a linear memory-less state feedback controller are derived, and an estimation method for the domain of admissible initial conditions is proposed from which all solutions of the systems under study converge exponentially to an ellipsoid with a prescribed convergence rate. Finally, a simulation example is provided to show the effectiveness of the developed approach. © 1982-2012 IEEE.

Song J.,Nanjing University of Science and Technology | Song J.,Nanjing University of Aeronautics and Astronautics | Kulinich S.A.,Tokai University | Kulinich S.A.,Aston University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2015

For all-solution-processed (ASP) devices, transparent conducting oxide (TCO) nanocrystal (NC) inks are anticipated as the next-generation electrodes to replace both those synthesized by sputtering techniques and those consisting of rare metals, but a universal and one-pot method to prepare these inks is still lacking. A universal one-pot strategy is now described; through simply heating a mixture of metal-organic precursors a wide range of TCO NC inks, which can be assembled into high-performance electrodes for use in ASP optoelectronics, were synthesized. This method can be used for various oxide NC inks with yields as high as 10 g. The formed NCs are of high crystallinity, uniform morphology, monodispersity, and high ink stability and feature effective doping. Therefore, the inks can be readily assembled into films with a surface roughness of 1.6 nm. Typically, a sheet resistance of 110 Ω sq-1 can be achieved with a transmittance of 88%, which is the best performance for TCO NC ink-based electrodes described to date. These electrodes can thus drive a polymer light-emitting diode (PLED) with a luminance of 2200 cdm-2 at 100 mA cm-2. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Liu Y.,CAS Institute of Automation | Liu J.,CAS Institute of Automation | Li Z.,CAS Institute of Automation | Tang J.,Nanjing University of Science and Technology | Lu H.,CAS Institute of Automation
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2013

In this paper, we propose a novel Weakly-Supervised Dual Clustering (WSDC) approach for image semantic segmentation with image-level labels, i.e., collaboratively performing image segmentation and tag alignment with those regions. The proposed approach is motivated from the observation that super pixels belonging to an object class usually exist across multiple images and hence can be gathered via the idea of clustering. In WSDC, spectral clustering is adopted to cluster the super pixels obtained from a set of over-segmented images. At the same time, a linear transformation between features and labels as a kind of discriminative clustering is learned to select the discriminative features among different classes. The both clustering outputs should be consistent as much as possible. Besides, weakly-supervised constraints from image-level labels are imposed to restrict the labeling of super pixels. Finally, the non-convex and non-smooth objective function are efficiently optimized using an iterative CCCP procedure. Extensive experiments conducted on MSRC and Label Me datasets demonstrate the encouraging performance of our method in comparison with some state-of-the-arts. © 2013 IEEE.

Gao Q.,Hefei University of Technology | Gao Q.,City University of Hong Kong | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | And 2 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2013

This paper investigates the universal fuzzy model and universal fuzzy controller problems for stochastic nonaffine nonlinear systems. The underlying mechanism of stochastic fuzzy logic is first discussed, and a stochastic generalized fuzzy model with new stochastic fuzzy rule base is then given. Based on their function approximation capability, these kinds of stochastic generalized fuzzy models are shown to be universal fuzzy models for stochastic nonaffine nonlinear systems under some sufficient conditions. An approach to stabilization controller design for stochastic nonaffine nonlinear systems is then developed through their stochastic generalized Takagi-Sugeno (T-S) fuzzy approximation models. Then, the results of universal fuzzy controllers for two classes of stochastic nonlinear systems, along with constructive procedures to obtain the universal fuzzy controllers, are also provided, respectively. Finally, a numerical example is presented to illustrate the effectiveness of the proposed approach. © 1993-2012 IEEE.

Qiu J.,Harbin Institute of Technology | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Gao H.,Harbin Institute of Technology
IEEE Transactions on Fuzzy Systems | Year: 2013

This paper investigates the problem of robust H∞ output feedback control for a class of continuous-time Takagi-Sugeno (T-S) fuzzy affine dynamic systems with parametric uncertainties and input constraints. The objective is to design a suitable constrained piecewise affine static output feedback controller, guaranteeing the asymptotic stability of the resulting closed-loop fuzzy control system with a prescribed H∞ disturbance attenuation level. Based on a smooth piecewise quadratic Lyapunov function combined with S-procedure and some matrix inequality convexification techniques, some new results are developed for static output feedback controller synthesis of the underlying continuous-time T-S fuzzy affine systems. It is shown that the controller gains can be obtained by solving a set of linear matrix inequalities (LMIs). Finally, three examples are provided to illustrate the effectiveness of the proposed methods. © 1993-2012 IEEE.

Qiu J.,Harbin Institute of Technology | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Gao H.,Harbin Institute of Technology
IEEE Transactions on Fuzzy Systems | Year: 2011

This paper investigates the problem of robust ℋ∞ output-feedback control for a class of networked nonlinear systems with multiple packet dropouts. The nonlinear plant is represented by Takagi-Sugeno (T-S) fuzzy affine dynamic models with norm-bounded uncertainties, and stochastic variables that satisfy the Bernoulli random binary distribution are adopted to characterize the data-missing phenomenon. The objective is to design an admissible output-feedback controller that guarantees the stochastic stability of the resulting closed-loop system with a prescribed ℋ∞ disturbance attenuation level. It is assumed that the plant premise variables, which are often the state variables or their functions, are not measurable so that the controller implementation with state-space partition may not be synchronous with the state trajectories of the plant. Based on a piecewise quadratic Lyapunov function combined with an S-procedure and some matrix inequality convexifying techniques, two different approaches to robust output-feedback controller design are developed for the underlying T-S fuzzy affine systems with unreliable communication links. The solutions to the problem are formulated in the form of linear matrix inequalities (LMIs). Finally, simulation examples are provided to illustrate the effectiveness of the proposed approaches. © 2011 IEEE.

Zhang C.,City University of Hong Kong | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Gao H.,Harbin Institute of Technology | And 2 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2011

This paper investigates the problem of H∞ filtering for a class of nonlinear discrete-time systems with measurement quantization and packet dropouts. Each output is transmitted via an independent communication channel, and the phenomenon of packet dropouts in transmission is governed by an individual random binary distribution, while the quantization errors are treated as sector-bound uncertainties. Based on a piecewise-Lyapunov function, an approach to the design of H∞-piecewise filter is proposed such that the filtering-error system is stochastically stable with a guaranteed H∞ performance. Some slack matrices are introduced to facilitate the filter design procedure by eliminating the coupling between the Lyapunov matrices and the system matrices. The filter parameters can be obtained by solving a set of linear-matrix inequalities (LMIs), which are numerically tractable with commercially available software. Finally, two illustrative examples are provided to show the effectiveness of the proposed method. © 2011 IEEE.

Qiu J.,Harbin Institute of Technology | Qiu J.,City University of Hong Kong | Feng G.,City University of Hong Kong | Feng G.,Nanjing University of Science and Technology | Gao H.,Harbin Institute of Technology
IEEE Transactions on Fuzzy Systems | Year: 2011

This paper investigates the problem of robust ℋ∞state estimation for a class of multichannel networked nonlinear systems with multiple packet dropouts. The nonlinear plant is represented by TakagiSugeno (TS) fuzzy-affine dynamic models with norm-bounded uncertainties, and stochastic variables with general probability distributions are adopted to characterize the data missing phenomenon in output channels. The objective is to design an admissible state estimator guaranteeing the stochastic stability of the resulting estimation-error system with a prescribed ℋ ∞disturbance attenuation level. It is assumed that the plant premise variables, which are often the state variables or their functions, are not measurable so that the estimator implementation with state-space partition may not be synchronized with the state trajectories of the plant. Based on a piecewise-quadratic Lyapunov function combined with S -procedure and some matrix-inequality-convexifying techniques, two different approaches are developed to robust filtering design for the underlying TS fuzzy-affine systems with unreliable communication links. All the solutions to the problem are formulated in the form of linear-matrix inequalities (LMIs). Finally, simulation examples are provided to illustrate the effectiveness of the proposed approaches. © 2006 IEEE.

Wang J.,Nanjing University of Science and Technology | Song Y.,Nanjing University of Science and Technology | Li Z.-H.,Nanjing University of Science and Technology | Kempf A.,University of Duisburg - Essen | He A.-Z.,Nanjing University of Science and Technology
Optics Letters | Year: 2015

Flame chemiluminescence tomography (FCT) has been widely used in flame diagnostics for three-dimensional (3D), spatially resolved measurements of instantaneous flame geometry and, to some extent, of species concentrations. However, in most studies, tomographic reconstructions are based on a traditional parallel projection model. Due to the light collection characteristics of a lens, a parallel projection model is not appropriate for the practical optical setups that are used for emission imaging, particularly at small F-numbers. Taking the light collection effect of the lens into account, this Letter establishes a complete and novel tomographic theory for a multi-directional tomography system consisting of a lens and CCD cameras. A modified camera calibration method is presented first. It determines the exact spatial locations and intrinsic parameters of the cameras. A 3D projection model based on the lens imaging theory is then proposed and integrated into the multiplicative algebraic reconstruction technique (MART). The new approach is demonstrated with a 12-camera system that is used to reconstruct the emission field of a propane flame, thereby resolving space and time. © 2015 Optical Society of America.

Yang J.,Nanjing University of Science and Technology | Yang J.,California Institute of Technology | Zhang L.,Hong Kong Polytechnic University | Xu Y.,Harbin Institute of Technology | Yang J.-Y.,Nanjing University of Science and Technology
Pattern Recognition | Year: 2012

The newly-emerging sparse representation-based classifier (SRC) shows great potential for pattern classification but lacks theoretical justification. This paper gives an insight into SRC and seeks reasonable supports for its effectiveness. SRC uses L1-optimizer instead of L0- optimizer on account of computational convenience and efficiency. We re-examine the role of L1-optimizer and find that for pattern recognition tasks, L1-optimizer provides more classification meaningful information than L0-optimizer does. L0-optimizer can achieve sparsity only, whereas L1-optimizer can achieve closeness as well as sparsity. Sparsity determines a small number of nonzero representation coefficients, while closeness makes the nonzero representation coefficients concentrate on the training samples with the same class label as the given test sample. Thus, it is closeness that guarantees the effectiveness of the L1-optimizer based SRC. Based on the closeness prior, we further propose two kinds of class L1-optimizer classifiers (CL1C), the closeness rule based CL1C (C-CL1C) and its improved version: the Lasso rule based CL1C (L-CL1C). The proposed classifiers are evaluated on five databases and the experimental results demonstrate advantages of the proposed classifiers over SRC in classification performance and computational efficiency for large sample size problems. © 2011 Elsevier Ltd. All rights reserved.

Song C.-J.,Nanjing University of Science and Technology | Zhang Y.,Suzhou University of Science and Technology
International Journal of Theoretical Physics | Year: 2015

Based on El-Nabulsi-Birkhoff fractional equations, Lie symmetry and the Hojman conserved quantity, the Noether conserved quantity deduced indirectly by the Lie symmetry and adiabatic invariants of Lie symmetrical perturbation are studied under the framework of El-Nabulsi’s fractional model. Firstly, Lie symmetry and the Hojman conserved quantity are obtained, including the equations of motion of EI-Nabulsi’s fractional Birkhoff system, the determining equations of Lie symmetry for the system and the generalization of the Hojman theorem. Secondly, the Noether conserved quantity deduced indirectly by the Lie symmetry is obtained. Thirdly, the adiabatic invariants of Lie symmetrical perturbation for disturbed EI-Nabulsi’s fractional Birkhoff system is achieved, including the disturbed El-Nabulsi-Birkhoff fractional equations, the determining equations of Lie symmetrical perturbation and adiabatic invariants for disturbed El-Nabulsi’s fractional Birkhoff system. Fourthly, adiabatic invariants and exact invariants under the special ifinitesimal transformations are presented. Finally, the Hojman-Urrutia problem is discussed to illustrate the application of these methods and results. © 2014, Springer Science+Business Media New York.

Shi S.,Nanjing University of Science and Technology | Choi W.-W.,Macau University of Science and Technology | Che W.,Nanjing University of Science and Technology | Tam K.-W.,Macau University of Science and Technology | Xue Q.,City University of Hong Kong
IEEE Microwave and Wireless Components Letters | Year: 2012

A novel microstrip ultra-wideband (UWB) differential filter with narrow notched band based on the transversal signal- interference concept is presented. In order to enhance the interference immunity from undesired signals efficiently, the notched band is implemented by coupling with quarter wavelength shorted-line at input and output ports. By taking advantage of the bandgap characteristic of defected ground structure (DGS), a slot-line DGS is used for improving the common-mode rejection. In this work, at the center frequency of the notched band which is 2.45 GHz, about 7.3% bandwidth (2.35-2.53 GHz) is realized by full-wave simulator. Agreement between experiment and simulation is observed. © 2012 IEEE.

Lai Z.,Harbin Institute of Technology | Xu Y.,Harbin Institute of Technology | Yang J.,Nanjing University of Science and Technology | Tang J.,Nanjing University of Science and Technology | Zhang D.,Hong Kong Polytechnic University
IEEE Transactions on Image Processing | Year: 2013

The classical linear discriminant analysis has undergone great development and has recently been extended to different cases. In this paper, a novel discriminant subspace learning method called sparse tensor discriminant analysis (STDA) is proposed, which further extends the recently presented multilinear discriminant analysis to a sparse case. Through introducing the L1 and L2 norms into the objective function of STDA, we can obtain multiple interrelated sparse discriminant subspaces for feature extraction. As there are no closed-form solutions, k-mode optimization technique and the L 1 norm sparse regression are combined to iteratively learn the optimal sparse discriminant subspace along different modes of the tensors. Moreover, each non-zero element in each subspace is selected from the most important variables/factors, and thus STDA has the potential to perform better than other discriminant subspace methods. Extensive experiments on face databases (Yale, FERET, and CMU PIE face databases) and the Weizmann action database show that the proposed STDA algorithm demonstrates the most competitive performance against the compared tensor-based methods, particularly in small sample sizes. © 1992-2012 IEEE.

Qian J.,Nanjing University of Science and Technology | Yang J.,Nanjing University of Science and Technology | Yang J.,California Institute of Technology | Xu Y.,Harbin Institute of Technology
IEEE Transactions on Image Processing | Year: 2013

This paper presents a robust but simple image feature extraction method, called image decomposition based on local structure (IDLS). It is assumed that in the local window of an image, the macro-pixel (patch) of the central pixel, and those of its neighbors, are locally linear. IDLS captures the local structural information by describing the relationship between the central macro-pixel and its neighbors. This relationship is represented with the linear representation coefficients determined using ridge regression. One image is actually decomposed into a series of sub-images (also called structure images) according to a local structure feature vector. All the structure images, after being down-sampled for dimensionality reduction, are concatenated into one super-vector. Fisher linear discriminant analysis is then used to provide a low-dimensional, compact, and discriminative representation for each super-vector. The proposed method is applied to face recognition and examined using our real-world face image database, NUST-RWFR, and five popular, publicly available, benchmark face image databases (AR, Extended Yale B, PIE, FERET, and LFW). Experimental results show the performance advantages of IDLS over state-of-the-art algorithms. © 2013 IEEE.

Xu Y.,Harbin Institute of Technology | Zhang D.,Hong Kong Polytechnic University | Yang J.,Nanjing University of Science and Technology | Yang J.-Y.,Nanjing University of Science and Technology
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2011

In this paper, we propose a two-phase test sample representation method for face recognition. The first phase of the proposed method seeks to represent the test sample as a linear combination of all the training samples and exploits the representation ability of each training sample to determine M nearest neighbors for the test sample. The second phase represents the test sample as a linear combination of the determined M nearest neighbors and uses the representation result to perform classification. We propose this method with the following assumption: the test sample and its some neighbors are probably from the same class. Thus, we use the first phase to detect the training samples that are far from the test sample and assume that these samples have no effects on the ultimate classification decision. This is helpful to accurately classify the test sample. We will also show the probability explanation of the proposed method. A number of face recognition experiments show that our method performs very well. © 2011 IEEE.

Li Z.,Nanjing University of Science and Technology | Liu J.,CAS Institute of Automation | Tang J.,Nanjing University of Science and Technology | Lu H.,CAS Institute of Automation
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2015

To uncover an appropriate latent subspace for data representation, in this paper we propose a novel Robust Structured Subspace Learning (RSSL) algorithm by integrating image understanding and feature learning into a joint learning framework. The learned subspace is adopted as an intermediate space to reduce the semantic gap between the low-level visual features and the high-level semantics. To guarantee the subspace to be compact and discriminative, the intrinsic geometric structure of data, and the local and global structural consistencies over labels are exploited simultaneously in the proposed algorithm. Besides, we adopt the ℓ2,1 -norm for the formulations of loss function and regularization respectively to make our algorithm robust to the outliers and noise. An efficient algorithm is designed to solve the proposed optimization problem. It is noted that the proposed framework is a general one which can leverage several well-known algorithms as special cases and elucidate their intrinsic relationships. To validate the effectiveness of the proposed method, extensive experiments are conducted on diversity datasets for different image understanding tasks, i.e., image tagging, clustering, and classification, and the more encouraging results are achieved compared with some state-of-the-art approaches. © 1979-2012 IEEE.

Xu J.,Nanjing University of Science and Technology | Xu J.,Shaoguan University | Yang J.,Nanjing University of Science and Technology | Lai Z.,Harbin Institute of Technology
Information Sciences | Year: 2013

K-local hyperplane distance nearest neighbor (HKNN) classifier is an improved K-nearest neighbor (KNN) algorithm that has been successfully applied to pattern classification. This paper embeds the decision rule of HKNN classifier into the discriminant analysis model to develop a new feature extractor. The obtained feature extractor is called K-local hyperplane distance nearest neighbor classifier oriented local discriminant analysis (HOLDA), in which a regularization item is imposed on the original HKNN algorithm to obtain a more reliable distance metric. Based on this distance metric, the homo-class and hetero-class local scatters are characterized in HOLDA. By maximizing the ratio of the hetero-class local scatter to the homo-class local scatter, we obtain a subspace which is suitable for feature extraction and classification. In general, this paper provides a framework for building a feature extractor from the decision rule of a classifier. By this means, the feature extractor and classifier can be seamlessly integrated. Experimental results on four databases demonstrate that the integrated pattern recognition system is effective. © 2013 Elsevier Inc. All rights reserved.

Yuan Y.-H.,Jiangnan University | Sun Q.-S.,Nanjing University of Science and Technology
Pattern Recognition | Year: 2014

Multiset canonical correlation analysis (MCCA) is a powerful technique for analyzing linear correlations among multiple representation data. However, it usually fails to discover the intrinsic geometrical and discriminating structure of multiple data spaces in real-world applications. In this paper, we thus propose a novel algorithm, called graph regularized multiset canonical correlations (GrMCCs), which explicitly considers both discriminative and intrinsic geometrical structure in multiple representation data. GrMCC not only maximizes between-set cumulative correlations, but also minimizes local intraclass scatter and simultaneously maximizes local interclass separability by using the nearest neighbor graphs on within-set data. Thus, it can leverage the power of both MCCA and discriminative graph Laplacian regularization. Extensive experimental results on the AR, CMU PIE, Yale-B, AT&T, and ETH-80 datasets show that GrMCC has more discriminating power and can provide encouraging recognition results in contrast with the state-of-the-art algorithms. © 2014 Elsevier Ltd.

Zhao Y.,City College of New York | Zhao Y.,Nanjing University of Science and Technology | Seredych M.,City College of New York | Zhong Q.,Nanjing University of Science and Technology | Bandosz T.J.,City College of New York
RSC Advances | Year: 2013

New composites of a copper-based metal-organic framework and graphite oxide modified by urea (GO-U) were synthesized. The materials and the parent composite components were characterized using X-ray diffraction, FT-IR spectroscopy, potentiometric titration, sorption of nitrogen, thermal analysis, elemental analysis, Raman spectroscopy, UV-Vis spectroscopy, and scanning electron microscopy. The introduction of GO-U does not prevent the formation of MOF crystal structure. The synergistic effect of the composite formation is clearly seen in the surface features. The new materials exhibit a unique texture, high porosity and nitrogen enriched surface chemistry. Incorporation of amino groups in the specific chemical and structural environment enhances CO2 adsorption. Therefore, this kind of composites has a potential application in CO2 capture technologies to remit global warming. © 2013 The Royal Society of Chemistry.

Li J.,Zhejiang University of Technology | Chen Y.,Nanjing University of Science and Technology
Optics and Laser Technology | Year: 2012

Based on the theory of paraxial electromagnetic beams in anisotropic medium, propagation properties of a linearly polarized confluent hypergeometric (HyG) beam through uniaxial crystals orthogonal to the optical axis are investigated. Analytical expressions are derived for the resultant optical field components. Effects of separate beam parameters together with the ratio of refractive indices of crystals on transversal intensity distributions are revealed by numerical calculations, respectively. It is shown that the beam profile finally converts into an elliptical shape due to influences of anisotropic crystals. Moreover, it is also indicated that through suitable selection of parameters, types of the optical vortices of resultant field would change from a central dark spot to a slight dark ring or an axial shadow during the propagation. These numerical results may provide alternative advantages to the trapping of tiny particles by utilizing HyG beams in practical experiments. © 2011 Elsevier Ltd. All rights reserved.

Wang J.-T.,Huaibei Normal University | Chen D.-B.,Huaibei Normal University | Chen H.-Y.,Nanjing University of Science and Technology | Yang J.-Y.,Nanjing University of Science and Technology
Pattern Recognition Letters | Year: 2012

This article presents an approach for pedestrian detection and tracking from infrared imagery. The GMM background model is first deployed to separate the foreground candidates from background, then a shape describer is introduced to construct the feature vector for pedestrian candidates, and a SVM classifier is trained based on datasets generated from infrared images or manually. After detecting the pedestrian based on the SVM classifier, a multi-cues fusing algorithm is provided to facilitate the task of pedestrian tracking using both edge feature and intensity feature under the particle filter framework. Experimental results with various Infrared Video Database are reported to demonstrate the accuracy and robustness of our algorithm. © 2011 Elsevier B.V. All rights reserved.

Xiang Z.,Nanjing University of Science and Technology | Qiao C.,Nanjing University of Science and Technology | Mahmoud M.S.,King Fahd University of Petroleum and Minerals
Journal of the Franklin Institute | Year: 2012

This paper investigates the problem of robust H ∞ filtering for switched stochastic systems under asynchronous switching. The so-called asynchronous switching means that the switching between the filters and system modes is asynchronous. The aim is to design a filter ensuring robust exponential mean square stability and a prescribed H ∞ performance level for the filtering error systems. Based on the average dwell time approach and piecewise Lyapunov functional technique, sufficient conditions for the existence of the robust H ∞ filter are derived, and the proposed filter can be obtained by solving a set of LMIs(linear matrix inequalities). Finally, a numerical example is given to show the effectiveness of the proposed approach. © 2012 The Franklin Institute.

Li P.,University of Aizu | Guo S.,University of Aizu | Zhuang W.,University of Waterloo | Ye B.,Nanjing University of Science and Technology
IEEE Journal on Selected Areas in Communications | Year: 2014

Cooperative communication (CC) can offer high channel capacity and reliability in an efficient and low-cost way by forming a virtual antenna array among single-antenna nodes that cooperatively share their antennas. It has been well recognized that the selection of relay nodes plays a critical role in the performance of multiple source-destination pairs. Unfortunately, all prior work has made an unrealistic assumption that spectrum resources are unlimited and each source-destination pair can communicate over a dedicated channel with no mutual interference. In this paper, we study the problem of maximizing the minimum transmission rate among multiple source-destination pairs using CC in a cognitive radio network (CRN). We jointly consider the relay assignment and channel allocation under a finite set of available channels, where the interference must be considered. In order to improve the spectrum efficiency, we exploit the network coding opportunities existing in CC that can further increase the capacity. Such max-min rate problems for cognitive and cooperative communications are proved to be NP-hard and the corresponding MINLP (Mixed-Integer Nonlinear Programming) formulations are developed. Moreover, we apply the reformulation and linearization techniques to the original optimization problems with nonlinear and nonconvex objective functions such that our proposed algorithms can produce high competitive solutions in a timely manner. Extensive simulations are conducted to show that the proposed algorithms can achieve high spectrum efficiency in terms of providing a much improved max-min transmission rate under various network settings. © 1983-2012 IEEE.

Yan S.,University of Maryland University College | Yan S.,Nanjing University of Science and Technology | Jian G.,University of Maryland University College | Zachariah M.R.,University of Maryland University College
ACS Applied Materials and Interfaces | Year: 2012

In this work, we present a first time fabrication of thermite-based nanofiber mats with a nitrocellulose composite energetic binder to create a new class of energetic 1D nanocomposite. The as prepared thermite based nanofibrous mats were characterized and tested for their burning behavior, and compared with the pure nitrocellulose and nanoaluminum incorporated nanofibers for their combustion performances. Thermite-based nanofibers show enhanced burning rates in combustion tests, which correlate to the mass loading of nanothermite relative to binder in nanofibers. The electrospinning method demonstrates the possibility of avoiding some of the problems associated with melt casting nanometalized propellants. © 2012 American Chemical Society.

Xiang Z.,Nanjing University of Science and Technology | Qiao C.,Nanjing University of Science and Technology | Mahmoud M.S.,King Fahd University of Petroleum and Minerals
Journal of the Franklin Institute | Year: 2012

This paper is concerned with the finite-time stability, boundedness and H ∞ control problems for a class of switched stochastic systems. Using the average dwell time method and the multiple Lyapunov-like function technique, some sufficient conditions are proposed to guarantee the finite-time properties for the switched stochastic systems in the form of matrix inequalities. Also, a state feedback controller for the finite-time H ∞ control problem is obtained. An example is employed to verify the effectiveness of the proposed method. © 2011 The Franklin Institute.

Che W.,Nanjing University of Science and Technology | Gu L.,Nanjing University of Science and Technology | Chow Y.L.,University of Waterloo
IEEE Microwave and Wireless Components Letters | Year: 2010

Double-sided parallel strip line (DSPSL) is a versatile microwave transmission line. With an offset, it allows for large variations of the characteristic impedance and therefore flexibility for the design of novel microwave devices. In this letter, a formula for the characteristic impedance of DSPSL is derived by the fuzzy EM method and verified by commercial software. Very good agreement is observed. © 2010 IEEE.

Yoshimura A.,University of Minnesota | Middleton K.R.,University of Minnesota | Zhu C.,Nanjing University of Science and Technology | Nemykin V.N.,University of Minnesota | Zhdankin V.V.,University of Minnesota
Angewandte Chemie - International Edition | Year: 2012

Look, no metal: A metal-free catalytic procedure for aziridination of alkenes using tetrabutylammonium iodide as the catalyst, m-chloroperoxybenzoic acid (mCPBA) as the terminal oxidant, and N-aminophthalimide as the nitrenium precursor has been developed (see scheme; right: X-ray structure of one of the products). Control experiments suggests that the active oxidant is in situ generated hypoiodous acid (HIO). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ding J.,Nanjing University of Science and Technology | Zhong Q.,Nanjing University of Science and Technology | Zhang S.,Nanjing AIREP Environmental Protection Technology Co.
Fuel Processing Technology | Year: 2014

A novel oxidation-removal process for simultaneous removal of NO X and SO2 was developed, which utilized the catalytic ozonation over Ce-Ti catalyst and assisted with a glass made ammonia-based washing tower. Compared with conventional flue gas treatment, the present method acquires non-secondary pollution, minimal waste production and low operating costs. The main byproducts, ammonia sulfate and nitrate, are important fertilizers and industrially raw materials. A maximum removal of 95% for NO X and nearly complete SO2 removal were obtained with the assistance of washing tower under the following experimental conditions: O 3 concentration, 8.5 mg·L- 1; flow of oxidant mixtures, 100 mL·min- 1; simulated flue gas temperature, 120 °C; H2O flow, 2.4 mL·min- 1; and total gas flow, 400 mL·min- 1. The reaction mechanisms are discussed, and the final oxidation products are characterized. The experimental results show that the OH radicals from catalytic ozonation have an oxidation-removal effect of NOX and SO2. The multipollutant capacity of the washing tower is largely enhanced with the Ce-Ti catalyst. And the present method performs better stability with the assistance of the washing tower. © 2014 Published by Elsevier B.V.

He C.,East China Jiaotong University | He C.,Nanjing University of Science and Technology
International Journal of Machine Learning and Cybernetics | Year: 2014

Approximation capabilities are important and primary properties of neural networks and fuzzy neural networks (FNNs). Neural networks have been successfully applied in many fields since they can work as approximators in nature. Many scholars research FNNs' approximation abilities for continuous fuzzy functions. It is concluded that FNNs can work as approximators for continuous fuzzy functions if the fuzzy functions satisfy some specified conditions. However, the problem whether FNNs can work as approximators for discontinuous fuzzy functions is not solved completely until now. In this work, we focus on the approximation of polygonal FNN for discontinuous fuzzy functions in sense of Choquet integral norms. We first introduce the Choquet integral norms in sub-additive fuzzy measure. Then the universal approximation of polygonal FNNs for fuzzy valued functions in sense of Choquet integral norms is analyzed in this paper. It is proved that the polygonal FNNs can work as approximators for fuzzy valued functions in the sense of Choquet integral norms with respect to sub-additive fuzzy measure. © 2013 Springer-Verlag Berlin Heidelberg.

Bao B.C.,Jiangsu Teachers University of Technology | Liu Z.,Nanjing University of Science and Technology | Xu J.P.,Southwest Jiaotong University
Electronics Letters | Year: 2010

By replacing Chua's diode in the canonical Chua's oscillator with a smooth flux-controlled memristor, a memristor based oscillator is presented. The memristor oscillator generates a steady periodic orbit and has a transition from transient chaotic to steady periodic behaviour. The complicated dynamical behaviour is extremely dependent on the initial condition of the memristor. © 2010 The Institution of Engineering and Technology.

Ding Y.,Nanjing University of Science and Technology | Wang P.,China First Metallurgical Construction Co. | Yu S.,Nanjing University of Science and Technology
Measurement: Journal of the International Measurement Confederation | Year: 2015

This paper introduces a new monitoring technology which is characterized by the use of distributed sensing optical fiber to monitor the deformation state of the SMW pile under the stress. With distributed sensing optical fiber attached to the surface inside it, the H-pile is transformed into a pile that has self-sensing capacity. The transformation enables the H-pile to automatically acquire force deformation data such as H-pile flange strain, bending moment, and horizontal displacement. Through the analysis of the H-pile's force structure, a certain method of continuously calculating the pile bending moment, is proposed, with no need to determine the neutral axis' place, and thus achieving temperature self-compensation in the pile measurement. This kind of technology referred to above has been applied in some foundation pit engineering and achieved great success. © 2015 Elsevier Ltd. All rights reserved.

Hu K.,University of New Brunswick | Chen Z.,University of New Brunswick | Fu J.,University of New Brunswick | Fu J.,Nanjing University of Science and Technology
Composite Structures | Year: 2014

The dynamic response of an interface crack between magnetoelectroelastic and functionally graded elastic layers under anti-plane shear and in-plane electric and magnetic impacts is investigated by the integral transform method. Fourier and Laplace transforms are applied to reduce the mixed boundary value problem of the interface crack to dual integral equations, which are expressed in terms of a Fredholm integral equation of the second kind. The singular stress, electric displacement and magnetic induction fields near the crack tip are obtained asymptotically, and the stress intensity factors (SIFs), electric displacement intensity factors (EDIFs) and magnetic induction intensity factors (MIIFs) are determined accordingly. Laplace inverse transform is applied to get the field intensities in time domain. Numerical results show how the dynamic SIF is influenced by the magnetoelectric interactions, the material properties, the electric and magnetic loadings, and the geometric size ratios and the functionally graded parameter. © 2013 Elsevier Ltd.

Fang D.,Jiangsu Provincial Key Laboratory of Coast Wetland Bioresources and Environment Protection | Zhang H.-B.,Jiangsu Provincial Key Laboratory of Coast Wetland Bioresources and Environment Protection | Liu Z.-L.,Nanjing University of Science and Technology
Journal of Heterocyclic Chemistry | Year: 2010

(Chemical Equation Presented) Some halogen-free acyclic task-specific ionic liquids (TSILs) were synthesized as novel and recyclable catalysts for the synthesis of 5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyrans by one-pot three-component condensation of aromatic aldehyde, malononitrile (or ethyl cyanoacetate), and dimedone (or 1,3-cyclohexanedione) in water. The condensation accomplished successfully with good yields ranged from 86 to 94%. After the reaction, the products could simply be separated from the catalyst/water, and the catalyst could be reused at least 10 times without noticeably decreasing the catalytic activity. © 2009 HeteroCorporation.

He C.,East China Jiaotong University | Ye Y.,Nanjing University of Science and Technology
International Journal of Intelligent Systems | Year: 2011

We present two fuzzy conjugate gradient learning algorithms based on evolutionary algorithms for polygonal fuzzy neural networks (PFNN). First, we design a new algorithm, fuzzy conjugate algorithm based on genetic algorithm (GA). In the algorithm, we obtain an optimal learning constant η by GA and the experiment indicates the new algorithm always converges. Because the algorithm based on GA is a little slow in every iteration step, we propose to get the learning constant η by quantum genetic algorithm (QGA) in place of GA to decrease time spent in every iteration step. The PFNN tuned by the proposed learning algorithm is applied to approximation realization of fuzzy inference rules, and some experiments demonstrate the whole process. © 2011 Wiley Periodicals, Inc.

Bao B.,Changzhou University | Zhou G.,Southwest Jiaotong University | Xu J.,Southwest Jiaotong University | Liu Z.,Nanjing University of Science and Technology
IEEE Transactions on Power Electronics | Year: 2011

With the variation of circuit parameters, the operation-state regions of current-mode-controlled switching dc-dc converters can shift among stable period region, robust chaos region in continuous conduction mode, and intermittent chaos region in discontinuous conduction mode. This paper presents a unified approach to the operation-states analysis of switching dc-dc converters with ramp compensation. The piecewise map model of the converters is first derived. With the bifurcation analyses, two boundary classification equations of the orbit state shifting are then obtained. Finally, the operation-state regions are well classified. To verify the theoretical analysis results, 2-D bifurcation diagrams are simulated and experimentations with current-mode-controlled buck converter are conducted. It is revealed that regular and irregular (chaotic or intermittent) operation states can be generated depending on circuit parameters or control of ramp-compensation current. © 2011 IEEE.

Shi X.,Nanjing University of Science and Technology | Shi X.,Nanjing Institute of Technology | Chang S.,Nanjing University of Science and Technology
Mechatronics | Year: 2013

An extended state observer-based time-optimal control is proposed in this paper to achieve fast and precise point-to-point motions driven by a novel electromagnetic linear actuator. Working principle and characteristics of the actuator are analyzed. Total disturbance is estimated by an extended state observer, and the nonlinear system is compensated as a linear one. Time-optimal control is used to realize accurate point-to-point motions with minimal time. Comparative simulations and experimental results demonstrate the effectiveness of the proposed method, especially for non-repetitive point-to-point motions, and good positioning performance has been achieved in the presence of both model uncertainties and external disturbances. © 2013 Elsevier Ltd. All rights reserved.

Bao B.-C.,Jiangsu Teachers University of Technology | Xu J.-P.,Southwest Jiaotong University | Liu Z.,Nanjing University of Science and Technology
Chinese Physics Letters | Year: 2010

Unlike conventional chaotic systems, a memristor based chaotic circuit has an equilibrium set, whose stability is dependent on the initial state of the memristor. The initial state dependent dynamical behaviors of the memristor based chaotic circuit are investigated both theoretically and numerically. © 2010 Chinese Physical Society and IOP Publishing Ltd.

Zhu W.,Nanjing University of Science and Technology | Zhu W.,Beijing Institute of Technology | Xiao H.,Nanjing University of Science and Technology
Journal of Physical Chemistry C | Year: 2011

Ab initio molecular dynamics simulations have been performed to study the effects of different temperatures on the structure and stability of energetic solid silver azide. The results indicate that the N-N bond fission takes place at 523 K. The azide sublattice structure broke down prior to the silver sublattice. The initiation decomposition of silver azide is triggered by the N-N bond breaking. This will initiate many decomposition reactions and produce many nitrogen radicals, N2, and silver clusters. Silver azide has metallic properties at 573 K. As the temperature increases, its sensitivity becomes more and more sensitive. The calculated power spectra of the velocity autocorrelation function show that the low-frequency vibrational modes become more prominent than the high-frequency ones with increasing temperature. This would allow low-frequency vibrations and rotations to occur more freely than in the solid. © 2011 American Chemical Society.

Wang K.,Nanjing University of Science and Technology | Chen M.Z.Q.,University of Hong Kong | Hu Y.,Nanjing University of Science and Technology
Journal of the Franklin Institute | Year: 2014

In this paper, we consider the passive network synthesis problem of biquadratic impedances with at most four elements, motivated by the passive mechanical control. In order to solve this problem, a necessary and sufficient realizability condition for no more than three elements is obtained by some topological properties derived previously. Furthermore, the constraints on the possible realizations are used to derive the networks which can cover all the cases, and they are classified as several quartets. Through investigating one of the networks in each quartet, we obtain a necessary and sufficient condition for any biquadratic impedance to be realizable with at most four elements. Finally, the interlocking conditions are illustrated graphically, and numerical examples are given. © 2013 The Franklin Institute. Published by The Franklin Institute. All rights reserved.

Lu J.,University of Iowa | Yang G.,Nanjing University of Science and Technology | Ge J.,Nanjing University of Science and Technology
Computer Methods in Applied Mechanics and Engineering | Year: 2013

This article introduces a method for blending NURBS with Lagrangian representations in isogeometric analysis. In the blended representation, selected boundary edges or surfaces of a multivariate NURBS patch are parameterized in (rational) Lagrangian form. Lagrangian parameters are obtained by transforming the NURBS representation. The transformation, by construction, exactly preserves the original geometry. The transformation method is described in detail. In analysis, the blended form is useful for interfacing NURBS domains to finite element domains, or for imposing essential boundary conditions. The application is demonstrated using numerical examples. © 2013 Elsevier B.V..

Chen M.Z.Q.,University of Hong Kong | Wang K.,Nanjing University of Science and Technology | Shu Z.,University of Southampton | Li C.,CAS Academy of Mathematics and Systems Science
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2013

This paper investigates the simplified realization problem of a special class of positive-real admittances similar to biquadratic functions but with an extra pole at the origin, which is widely used in the analysis of suspension systems. The results in this paper are motivated by passive mechanical control with the inerter. The concept of strictly lower complexity is first defined, whose indices in this paper are the total number of elements, the number of resistors (dampers), and the number of capacitors (inerters). We then derive a necessary and sufficient condition for this class of admittance to be realized by the networks that are of strictly lower complexity than the canonical realization by the Foster Preamble method. To solve this problem, it is shown that it suffices to consider the following: 1) networks with at most four elements, 2) irreducible five-element resistor-inductor (RL) networks, and 3) irreducible five-element resisitor-inductor-capacitor (RLC) networks. Other cases are shown to be impossible. By finding their corresponding network configurations through a series of constraints and deriving the corresponding realizability conditions, the final condition can be obtained. Finally, the U-V plane and numerical examples are provided to illustrate the theoretical results. © 2004-2012 IEEE.

Wang K.,Nanjing University of Science and Technology | Chen M.Z.Q.,University of Hong Kong
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2012

This brief is concerned with the realization problem of biquadratic impedances, motivated by the recent development in passive mechanical control. This brief generalizes a realization procedure of a special class of biquadratic impedances to a more general form, and the resulting series-parallel RLC networks whose elements are no more than those in Bott-Duffin's networks are obtained without minimization. The realizability condition is proven by providing a constructive synthesis procedure. The series-parallel network obtained contains elements no more than those of Bott-Duffin's network when the impedance is nonregular. © 2004-2012 IEEE.

Xiong P.,University of Texas at Austin | Xiong P.,Nanjing University of Science and Technology | Liu B.,University of Texas at Austin | Teran V.,University of Texas at Austin | And 4 more authors.
ACS Nano | Year: 2014

Hybrid inorganic/graphene two-dimensional (2D) nanostructures can offer vastly open large surface areas for ion transport and storage and enhanced electron transport, representing a promising material platform for next-generation energy storage. Here we report chemically integrated hybrid ZnMn2O4/graphene nanosheets synthesized via a facile two-step method for greatly enhanced lithium storage capability. The hybrid 2D nanosheets are composed of ultrafine ZnMn2O4 nanocrystals with a mean diameter of ∼4 nm attached to and well dispersed on the surface of reduced graphene oxide sheets. The hybrid nanosheets based anode offers a high capacity of ∼800 mAh g-1 at a current rate of 500 mA g -1, excellent rate capability, and long-term cyclability with reversible capacity of ∼650 mAh g-1 over 1500 cycles at a current density of 2000 mA g-1. Moreover, when tested in a temperature range of ∼0-60 °C, the designed anode can maintain high discharge capacities from 570 to 820 mAh g-1. © 2014 American Chemical Society.

Du B.,Nanjing University of Science and Technology | Lam J.,University of Hong Kong | Shu Z.,University of Southampton
IET Control Theory and Applications | Year: 2012

This study addresses the strong stabilisation problem for continuous-time linear systems with an unknown input delay via dynamic output feedback controllers. A new criterion for dynamic output feedback stabilisability is proposed in terms of matrix inequalities with the separation of the controller gain with the Lyapunov matrix and the system matrices. Based on these new characterisations, an iterative algorithm is given to design the dynamic output feedback controllers with the initial values obtained by some proposed state feedback stabilisation methods. The effectiveness and merits of the proposed approach are shown through several examples. © 2012 The Institution of Engineering and Technology.

Zuo C.,Nanjing University of Science and Technology | Zuo C.,Nanyang Technological University | Zuo C.,Beijing Institute of Technology | Chen Q.,Nanjing University of Science and Technology | And 3 more authors.
Optics Express | Year: 2013

We present a high-speed transport-of-intensity equation (TIE) quantitative phase microscopy technique, named TL-TIE, by combining an electrically tunable lens with a conventional transmission microscope. This permits the specimen at different focus position to be imaged in rapid succession, with constant magnification and no physically moving parts. The simplified image stack collection significantly reduces the acquisition time, allows for the diffraction-limited through-focus intensity stack collection at 15 frames per second, making dynamic TIE phase imaging possible. The technique is demonstrated by profiling of microlens array using optimal frequency selection scheme, and time-lapse imaging of live breast cancer cells by inversion the defocused phase optical transfer function to correct the phase blurring in traditional TIE. Experimental results illustrate its outstanding capability of the technique for quantitative phase imaging, through a simple, non-interferometric, high-speed, high-resolution, and unwrapping-free approach with prosperous applications in micro-optics, life sciences and bio-photonics. ©2013 Optical Society of America.

Zhang B.,Nanjing University of Science and Technology | Lam J.,University of Hong Kong | Xu S.,Nanjing University of Science and Technology
Journal of the Franklin Institute | Year: 2014

This paper is concerned with the problems of reachable set estimation and state-feedback controller design for linear systems with distributed delays and bounded disturbance inputs. The disturbance inputs are assumed to be either unit-energy bounded or unit-peak bounded. First, based on the Lyapunov-Krasovskii functional approach and the delay-partitioning technique, delay-dependent conditions for estimating the reachable set of the considered system are derived. These conditions guarantee the existence of an ellipsoid that contains the system state under zero initial conditions. Second, the reachable set estimation is taken into account in the controller design. Here, the purpose is to determine an ellipsoid and find a state-feedback controller such that the determined ellipsoid contains the reachable set of the resulting closed-loop system. Sufficient conditions for the solvability of the control synthesis problem are obtained. Based on these results, the problem of how to design a controller such that the state of the resulting closed-loop system is contained in a prescribed ellipsoid is studied. Finally, numerical examples and simulation results are provided to show the effectiveness of the proposed analysis and design methods. © 2014 The Franklin Institute.

Du B.,Nanjing University of Science and Technology | Lam J.,University of Hong Kong | Zou Y.,Nanjing University of Science and Technology | Shu Z.,University of Southampton
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2013

This paper focuses on the stability analysis and controller synthesis of continuous-time Markovian jump time-delay systems with incomplete transition rate descriptions. A general stability criterion is formulated first for state-and input-delay Markovian jump time-delay systems with fully known transition rates. On the basis of the proposed condition, an equivalent condition is given under the assumption of partly known/unknown transition rates. A new design technique based on a projection inequality has been applied to design both state feedback and static output feedback controllers. All conditions can be readily verified by efficient algorithms. Finally, illustrative examples are provided to show the effectiveness of the proposed approach. © 2004-2012 IEEE.

Xu C.,Fuzhou University | Wang X.,Nanjing University of Science and Technology
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012

Graphene oxide sheets have been used as a kind of plane stabilizing agent to prepare Ag nanoparticle colloids. The utilization of graphene oxide has effects on the size of Ag nanoparticles and can enhance the stability of the as-prepared colloids. These graphene oxide stabilized Ag nanoparticles possess relatively uncapped surface, which behave good catalysis activity. Furthermore, we also prepared graphene oxide-mediated Au and Pt nanoparticle colloids through galvanic replacement reactions using graphene oxide-Ag nanoparticles as templates. © 2012 Elsevier B.V.

Dou L.,Nanjing University of Science and Technology | Dou J.,China Academy of Space Technology
IEEE Transactions on Advanced Packaging | Year: 2010

This paper applies the LaxFriedrichs technique, usually used in fluid dynamics, to transmission line sensitivity analysis. The LaxFriedrichs difference scheme for sensitivity analysis of both uniform and nonuniform transmission lines is derived. Based on this scheme, a method for analyzing multiconductor transmission line sensitivity, which does not need to be decoupled, is presented by combining with matrix operations. Using numerical experiments, the proposed method is compared with the characteristic method and the fast Fourier transform approach. With the presented method, the sensitivity of a nonlinear circuit including nonuniform multiconductor transmission lines is analyzed and the results are verified by the HSPICE perturbation method. The proposed method can be applied to either linear or nonlinear circuits, which include lossy nonuniform multiconductor transmission lines, and is proved to be efficient. © 2006 IEEE.

Hu Y.,Nanjing University of Science and Technology | Chen M.Z.Q.,University of Hong Kong | Shu Z.,University of Southampton
Journal of Sound and Vibration | Year: 2014

This paper investigates passive vehicle suspensions with inerters by considering multiple performance requirements including ride comfort, suspension deflection and tyre grip, where suspension deflection performance is novelly considered which is formulated as a part of objective functions and a constraint separately. Six suspension configurations are analyzed and the analytical solutions for each performance measure are derived. The conditions for each configuration to be strictly better than the simpler ones are obtained by presenting the analytical solutions of each configuration based on those of the simpler ones. Then, two stages of comparisons are given to show the performance limitations of suspension deflection for passive suspensions with inerters. In the first stage, it is shown that although the configurations with inerters can improve the mixed performance of ride comfort and tyre grip, the suspension deflection performance is significantly decreased simultaneously. In the second stage, it is shown that for passive suspensions with inerters, suspension deflection is the more basic limitation for both ride comfort and tyre grip performance by doing comparisons among mixed ride comfort and suspension deflection optimization, mixed ride comfort and tyre grip optimization, and mixed suspension deflection and tyre grip optimization. Finally, the problem of mixed ride comfort and tyre grip performance optimization with equal suspension deflection is investigated. The limitations of suspension deflection for each configuration are further highlighted. © 2013 Elsevier Ltd. All rights reserved.

Zhang Y.,Nanjing University of Science and Technology | Xu S.,Nanjing University of Science and Technology | Chu Y.,Huzhou Teachers College
International Journal of Robust and Nonlinear Control | Year: 2012

This paper proposes a sliding mode observer-controller design method for uncertain Markovian jump systems with time delays and uncertain switching probabilities. Both the structures of a sliding mode observer and a sliding mode controller are given. By the mode-dependent Lyapunov functional approach, a sufficient condition for the stochastic stability of the closed-loop system is given, which can be converted into a convex optimization problem. The reachability of the sliding surfaces in both the estimation error space and the state estimate space can be ensured by the presented control scheme. Finally, the effectiveness of the proposed design method is demonstrated by a simulation example. © 2011 John Wiley & Sons, Ltd.

Chen M.Z.Q.,University of Hong Kong | Wang K.,Nanjing University of Science and Technology | Zou Y.,Nanjing University of Science and Technology | Lam J.,University of Hong Kong | Lam J.,Nanjing University of Science and Technology
IEEE Transactions on Automatic Control | Year: 2013

In this note, we investigate the realization problem of a special class of positive-real admittances, which is common in vehicle suspension designs. The number of inerters and dampers is restricted to one in each case and the number of the springs is arbitrary. To solve the problem, we first convert a previous result by to a more direct form. A necessary and sufficient condition for realizability is then derived and explicit circuit arrangements are provided by assuming that the three-port network consisting of only springs after extracting the damper and the inerter has a well-defined impedance. To remove the assumption on the existence of a well-defined impedance, a condition is established on the topological property of the $n$-port network without a well-defined impedance to obtain an equivalent class of such networks so that the realizability condition is derived with realization. By combining the conditions with and without a well-defined impedance, the final realization result is obtained. © 1963-2012 IEEE.

Lam J.,University of Hong Kong | Zhang B.,Nanjing University of Science and Technology | Chen Y.,University of Hong Kong | Xu S.,Nanjing University of Science and Technology
International Journal of Robust and Nonlinear Control | Year: 2015

This paper is concerned with the reachable set estimation problem for discrete-time linear systems with multiple constant delays and bounded peak inputs. The objective is to check whether there exists a bounded set that contains all the system states under zero initial conditions. First, delay-dependent conditions for the solvability of the addressed problem are derived by employing a novel Lyapunov-Krasovskii functional. The obtained conditions are expressed in terms of matrix inequalities, which are linear when only one scalar variable is fixed. On the basis of these conditions, an ellipsoid containing the reachable set of the considered system is obtained. An approach for determining the smallest ellipsoid is also provided. Second, the approach and results developed in the first stage are generalized to the case of systems with polytopic parameter uncertainties, and delay-dependent conditions are given in the form of relaxed matrix inequalities. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed methods. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Zhang B.,Nanjing University of Science and Technology | Xu S.,Nanjing University of Science and Technology | Lam J.,University of Hong Kong
Neurocomputing | Year: 2014

This paper revisits the problem of passivity analysis for neural networks with time-varying delays. A new delay-dependent criterion is obtained in terms of linear matrix inequalities, guaranteeing that the input and output of the considered neural network satisfy a prescribed passivity-inequality constraint. This newly presented criterion does not require all the symmetric matrices involved in the employed quadratic Lyapunov-Krasovskii functional to be positive definite. This feature is remarkable since it sheds new light on the traditional ideas for constructing Lyapunov-Krasovskii functionals. More importantly, the conservatism of delay-dependent passivity conditions can be reduced due to the relaxation on the positive-definiteness of every Lyapunov matrix. It is shown both theoretically and numerically that the passivity criterion proposed in this paper is truly less conservative than some of the latest results in the literature. © 2014 Elsevier B.V.

Li L.,Nanjing University of Science and Technology | Yang J.,Yingyeda Electronics Company | Zhong Q.,Delta Electronics Inc
IEEE Transactions on Power Electronics | Year: 2011

The capacitor-clamped base cell is presented. Based on the base cell, a novel family of single-stage three-level (TL) ac choppers is proposed. The converters can directly transfer unsteady high ac voltage with distortion into regulated sinusoidal voltage with low THD. The circuit configuration is constituted of a TL converter, and input and output filters. The topological family includes buck, boost, buckboost, Cuk, Sepic, and Zeta modes. In order to achieve a reliable TL ac-ac conversion, a double transient voltage feedback control strategy of output voltage and the voltage across the clamp capacitor is introduced in this paper. A prototype of a 500 VA 220 V ± 10% 50 Hz ac/180-240 V 50 Hz ac converter is presented with the experimental results to prove that the converters have four improved advantages simultaneously, including the lower voltage stress of power switches, the bidirectional power flow, the low total harmonic distortion of output voltage, and the higher input power factor. © 2006 IEEE.

Zhang B.,Nanjing University of Science and Technology | Li Y.,Huzhou Teachers College
Signal Processing | Year: 2013

This paper is concerned with the problem of exponential L2- L∞ filter design for linear systems simultaneously with distributed delays, Markovian jumping parameters and norm-bounded parametric uncertainties. The purpose is to design full-order mode-dependent filters such that the filtering error system is not only mean-square robustly exponentially stable with a specified decay rate but also satisfies an L2- L∞ performance requirement. First, sufficient conditions for the stability and performance analysis of the filtering error system are derived based on a novel version of mode-dependent Lyapunov-Krasovskii functional. Then, delay-dependent and decay-rate-dependent conditions for the existence of desired filters are obtained in terms of linear matrix inequalities (LMIs). The filter coefficients can be computed by using feasible solutions of the presented LMIs. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed design method. © 2012 Elsevier B.V.

Tang L.,Nanjing Pengtu Power Supply Co., Ltd | Wu J.,Nanjing University of Science and Technology
Dianwang Jishu/Power System Technology | Year: 2012

At present the phasor measurement unit (PMU) based on clock synchronization technology becomes an important technical means to observe dynamic behavior of power system directly. When power system is in the N-1 failure state, traditional configuration of PMU cannot meet the demand of "whole system observable". If the condition of N-1 failure state is taken into account during the configuration of PMU, more PMUs should be configured than traditional configuration and the cost for the configuration will evidently increase. In allusion to it, a new optimal scheme for PMU configuration is proposed. Firstly, the vulnerability of power system and its branches is analyzed by generalized Tellegen's theorem; then the PMU configuration of the whole system and the PMU configuration considering N-1 failure state are performed; finally through the sorting of vulnerability and analyzing economic index and robustness, the configuration of PMU is determined. The feasibility of the proposed method is verified by simulation results of IEEE 14-bus system.

Doan M.T.,Nanjing University of Science and Technology | Doan M.T.,Hanoi University | Che W.Q.,Nanjing University of Science and Technology | Feng W.J.,Nanjing University of Science and Technology
Electronics Letters | Year: 2012

A tri-band bandpass filter (BPF) using square ring short stub loaded resonators (SRSLR) is presented. The characteristics of the triple-mode resonator are investigated by using even/odd mode analysis. The centre frequencies of the first three passbands can be independently controlled by tuning the dimensions of the SRSLR. Moreover, the filter has been implemented with eight transmission zeros to improve the selectivity. A prototype of a tri-band BPF centred at 2.4, 3.5 and 5.2GHz has been designed and fabricated. Good agreement can be found between the measured and simulated results. © 2012 The Institution of Engineering and Technology.

Mao Y.,University of Electronic Science and Technology of China | Zhang H.,University of Electronic Science and Technology of China | Xu S.,Nanjing University of Science and Technology
IEEE Transactions on Fuzzy Systems | Year: 2014

In this paper, we investigate the problem of exponential stability and asynchronous stabilization for a class of switched nonlinear systems. The Takagi and Sugeno (T-S) fuzzy model is employed to approximate the subnonlinear dynamic systems. With two-level functions, namely, crisp switching functions and local fuzzy weighting functions, we introduce continuous-time switched fuzzy systems, which inherently contain the features of the switched hybrid systems and T-S fuzzy systems. By the use of delicately constructed piecewise Lyapunov-like functions (PLFs) and minimum dwell time method, we obtain the exponential stability of the switched fuzzy systems, which allows us to have stable and unstable nonlinear subsystems. In practice, for the control problem, it inevitably takes some time to identify the system modes and apply the matched controller, the asynchronous phenomena between the system modes switching and the controllers switching generally exists. Based on the result of stability, the fuzzy state feedback controller under asynchronous switching is proposed for switched fuzzy systems. In addition, the lower bound of minimum dwell time can be obtained using convex optimization such that the switched fuzzy system can be exponentially stabilized if its minimum dwell time is larger than the bound. The stability results and control laws of the switched fuzzy systems are formulated in the form of linear matrix inequalities that are numerically feasible. Finally, two illustrated numerical examples are presented to show the effectiveness of the obtained theoretical results. © 1993-2012 IEEE.

Xia H.,Nanjing University of Science and Technology | Meng Y.S.,University of California at San Diego | Li X.,Dalian University of Technology | Yuan G.,Nanjing University of Science and Technology | Cui C.,Nanjing University of Science and Technology
Journal of Materials Chemistry | Year: 2011

For manganese oxides with low manganese oxidation states, such as MnO or Mn3O4, the electrochemical oxidation during potential cycling is critical to achieve high supercapacitor performance. In this work, dense Mn3O4 thin films are prepared by pulsed laser deposition. An electrochemical lithiation/delithiation process is applied to the Mn3O4 thin film, which leads to a nanoporous structure of the film and greatly increases the porosity of the film. The nanoporous MnOx thin film electrode exhibits significantly improved supercapacitive performance compared to the as-prepared Mn3O 4 thin film electrode. After 1000 cyclic voltammetric scans in 1 M Na2SO4 electrolyte between 0 and 1 V, only part of the surface of the as-prepared Mn3O4 thin film transforms into a MnO2 porous structure while the complete film of the nanoporous MnOx transforms into a MnO2 porous structure. It is believed that the nanoporous structure, which facilitates the electrolyte penetration, leads to the completion of electrochemical oxidation through the film during the potential cycling, resulting in promising supercapacitive performance of the film. © 2011 The Royal Society of Chemistry.

Song J.,Nanjing University of Aeronautics and Astronautics | Song J.,Nanjing University of Science and Technology | Li J.,Nanjing University of Science and Technology | Xu J.,Shanghai Institute of Technology | And 2 more authors.
Nano Letters | Year: 2014

Low cost and high conductivity make copper (Cu) nanowire (NW) electrodes an attractive material to construct flexible and stretchable electronic skins, displays, organic light-emitting diodes (OLEDs), solar cells, and electrochromic windows. However, the vulnerabilities that Cu NW electrodes have to oxidation, bending, and stretching still present great challenges. This work demonstrates a new Cu@Cu4Ni NW conductive elastomer composite with ultrahigh stability for the first time. Cu@Cu4Ni NWs, facilely synthesized through a one-pot method, have highly crystalline alloyed shells, clear and abrupt interfaces, lengths more than 50 μm, and smooth surfaces. These virtues provide the NW-elastomer composites with a low resistance of 62.4 ohm/sq at 80% transparency, which is even better than the commercial ITO/PET flexible electrodes. In addition, the fluctuation amplitude of resistance is within 2 ohm/sq within 30 days, meaning that at ΔR/R0 = 1, the actual lifetime is estimated to be more than 1200 days. Neither the conductivity nor the performances of OLED with elastomers as conductive circuits show evident degradation during 600 cycles of bending, stretching, and twisting tests. These high-performance and extremely stable NW elastomeric electrodes could endow great chances for transparent, flexible, stretchable, and wearable electronic and optoelectronic devices. © 2014 American Chemical Society.

Pei H.,CAS Shanghai Institute of Applied Physics | Li F.,CAS Shanghai Institute of Applied Physics | Wan Y.,Nanjing University of Science and Technology | Wei M.,CAS Shanghai Institute of Applied Physics | And 5 more authors.
Journal of the American Chemical Society | Year: 2012

Conjugates of DNA and gold nanoparticles (AuNPs) typically exploit the strong Au-S chemistry to self-assemble thiolated oligonucleotides at AuNPs. However, it remains challenging to precisely control the orientation and conformation of surface-tethered oligonucleotides and finely tune the hybridization ability. We herein report a novel strategy for spatially controlled functionalization of AuNPs with designed diblock oligonucleotides that are free of modifications. We have demonstrated that poly adenine (polyA) can serve as an effective anchoring block for preferential binding with the AuNP surface, and the appended recognition block adopts an upright conformation that favors DNA hybridization. The lateral spacing and surface density of DNA on AuNPs can also be systematically modulated by adjusting the length of the polyA block. Significantly, this diblock oligonucleotide strategy results in DNA-AuNPs nanoconjugates with high and tunable hybridization ability, which form the basis of a rapid plasmonic DNA sensor. © 2012 American Chemical Society.

Yang X.,Jiangsu University of Science and Technology | Song X.,Jiangsu University of Science and Technology | Chen Z.,Taiyuan University of Technology | Yang J.,Nanjing University of Science and Technology
International Journal of Machine Learning and Cybernetics | Year: 2012

Multigranulation rough set is a new and interesting topic in the theory of rough set. In this paper, the multigranulation rough sets approach is introduced into the incomplete information system. The tolerance relation, the similarity relation and the limited tolerance relations are employed to construct the optimistic and the pessimistic multigranulation rough sets, respectively. Not only the properties about these multigranulation rough sets are discussed, but also the relationships among these multigranulation rough sets models are explored. It is shown that by the multigranulation rough sets theory, the limited tolerance relations based multigranulation lower approximations fall between the tolerance and the similarity relations based multigranulation lower approximations, the limited tolerance relations based multigranulation upper approximations fall between the similarity and the tolerance relations based multigranulation upper approximations. Such results are consistent to those in single-granulation based rough sets models. © 2011 Springer-Verlag.

Wan Y.,Nanjing University of Science and Technology | Su Y.,Nanjing University of Science and Technology | Zhu X.,Nanjing University of Science and Technology | Liu G.,Shanghai Institute of Technology | Fan C.,CAS Shanghai Institute of Applied Physics
Biosensors and Bioelectronics | Year: 2013

Electrochemical immunosensors (EI) has attracted numerous interests due to its inherent benefits over the other transduction schemes, such as a high sensitivity, ease of use, a possible automation and integration in compact analytical devices, mostly cheap and relatively simple technology of its production. Thus, EIs have great potential in point of care (POC) diagnostics for early detection of diseases. During last decades, numerous efforts have been put into EIs development. Firstly, different fabrication methods and amplification strategies have been employed to achieve high sensitivity. To be pointed, nanotechnology has been involved in the fabrication and signal amplification of EIs, which present great superiority. Secondly, EI arrays have been used for multiparametric analysis. Thirdly, several attempts have been made to construct integrated systems, which showed promising applications for POC test. Several of them are commercially available for POC use. Herein, we will review briefly the recent achievements and progress in developing EIs towards POC diagnostics. © 2013 Elsevier B.V.

Gleiter H.,Institute of Nanotechnology | Gleiter H.,Nanjing University of Science and Technology | Schimmel T.,Institute of Nanotechnology | Schimmel T.,Nanjing University of Science and Technology | And 2 more authors.
Nano Today | Year: 2014

It is the aim of this review to discuss the preparation, the atomic structure and the properties of nanometer structured solids that consist either totally or partially of amorphous components. We shall try to present evidence suggesting that it is the variation of the boundary conditions applied for preparing these nano-structures that open the way to a variety of materials with new atomic arrangements/new properties ranging from nano-glasses to switchable atomic quantum transistors. In order to discuss the basic ideas, we shall consider (in the first part of this review) solid materials that are assembled of nanometer-sized crystalline or amorphous building blocks connected by interfaces. The resulting materials are called nano-crystalline materials (nc) and nano-glasses (NG). Nano-crystalline materials and nano-glasses are solid materials composed of nanometer-sized crystalline or nanometer-sized glassy regions connected by crystal/crystal or glass/glass interfaces. As the atomic structures of these interfaces differ from the ones in the building blocks, the atomic and electronic structures of these interfaces differ from the ones in the building blocks. The atomic and the electronic structures (and hence the properties) of nano-crystalline materials and/or nano-glasses differ from the ones of single crystals or of glasses, respectively, that are available today with the same chemical compositions. In the second part of this review solid materials will be discussed the properties of which are controlled by nanometer spaced solid/liquid or solid/gas interfaces. The first group of materials of this kind to be discussed are nano-porous metals with electrolyte or gas filled interconnected nanometer-sized ligaments. The properties of the resulting numerous solid/liquid or solid/gas interfaces may be controlled reversibly by external variables e.g. by applying an external voltage between an aqueous electrolyte in the pores and the nano-porous metal or by varying the chemical composition of the gas in the pores. Due to the high density (∼1015 mm-3) of nano-scale ligaments, the entire nano-porous material reacts and becomes a solid of macroscopic dimensions with tunable mechanical, electric, magnetic, etc. properties. The other group of materials to be discussed in the second section of this review are nanometer-sized single crystals embedded in an aqueous electrolyte. By varying the boundary conditions for the formation of these nanometer-sized crystals, the size, the shape and the electronic structure of these nanometer-sized crystals can be switched reversibly so that switchable quantum transistors are obtained. All of these findings may also be interpreted in a more general context suggesting that in all the above mentioned cases, complex structures evolve if the following four conditions are met: (i) a substrate or nucleation site, on which the structures can organize, (ii) a free volume providing the sterical degrees of freedom for building the new structures, (iii) a reservoir of building blocks (molecules, atoms, ions, crystallites, glassy clusters) from which the structures can be (reversibly or irreversibly) formed and finally (iv) confined geometries preventing the return to thermal equilibrium by preventing the growth of macroscopic single crystals. This general approach seems to open the way for understanding and developing the guidelines for the growth of new self-organized complex material systems far from thermal equilibrium. © 2014 Elsevier Ltd.

Zhao F.,Nanjing Agricultural University | Xie Q.,Nanjing Agricultural University | Xu M.,Nanjing Agricultural University | Wang S.,Nanjing University of Science and Technology | And 2 more authors.
Biosensors and Bioelectronics | Year: 2015

Cyclic adenosine monophosphate (cAMP) is an important small biological molecule associated with the healthy state of living organism. In order to realize highly sensitive and specific detection of cAMP, here an RNA aptamer and electrochemical impedance spectroscopy (EIS) based biosensor enhanced by gold nanoparticles electrodeposited on the surface of gold electrode is designed. The designed aptasensor has a wide effective measuring range from 50. pM to 250. pM with a detection limit of 50. pM in PBS buffer, and an effective measuring range from 50. nM to 1. μM with a detection limit of 50. nM in serum. The designed biosensor is also able to detect cAMP with high sensitivity, specificity, and stability. Since the biosensor can be easily fabricated with low cost and repeatedly used for at least two times, it owns great potential in wide application fields such as clinical test and food inspection, etc. © 2014 Elsevier B.V.

Hao Q.,Nanjing University of Science and Technology | Xia X.,Nanjing University of Science and Technology | Lei W.,Nanjing University of Science and Technology | Wang W.,Nanjing University of Science and Technology | Qiu J.,Dalian University of Technology
Carbon | Year: 2015

Shi Y.,Nanjing University of Science and Technology | Xia M.-Y.,University of Electronic Science and Technology of China | Chen R.-S.,Nanjing University of Science and Technology | Michielssen E.,University of Michigan | Lu M.,University of Texas at Arlington
IEEE Transactions on Antennas and Propagation | Year: 2011

Prior theoretical studies and experience confirm that the stability of marching-on-in-time (MOT) solvers pertinent to the analysis of scattering from free-standing three-dimensional perfect electrically conducting surfaces hinges on the accurate evaluation of MOT matrix elements resulting from a Galerkin discretization of the underlying time domain integral equation (TDIE). Unfortunately, the accurate evaluation of the four-dimensional spatial integrals involved in the expressions for these matrix elements is prohibitively expensive when performed by computational means. Here, a method that permits the quasi-exact evaluation of MOT matrix elements is presented. Specifically, the proposed method permits the analytical evaluation of three out of the four spatial integrations, leaving only one integral to be evaluated numerically. Since the latter has finite range and a piecewise smooth integrand, it can be evaluated to very high accuracy using standard quadrature rules. As a result, the proposed method permits the fast evaluation of MOT matrix elements with arbitrary (user-specified) accuracy. Extensive numerical experiments show that an MOT solver for the electric field TDIE that uses the proposed quasi-exact method is stable for a very wide range of time step sizes and yields solutions that decay exponentially after the excitation vanishes. © 2010 IEEE.

Zhao J.,Nanjing University of Science and Technology | Wang J.,Nanjing University of Science and Technology | Zhang G.,Nanjing University of Science and Technology | Li J.-L.,University of Electronic Science and Technology of China
IEEE Microwave and Wireless Components Letters | Year: 2013

A new microstrip ultra-wideband (UWB) bandpass filter (BPF) with two sharp notches using E-shaped resonator is proposed in this letter. The circuit topology and its corresponding electrical parameters of the initial microstrip UWB BPF are achieved by a variation of genetic algorithm (GA). Then, the resonance properties of the E-shaped resonator are studied. Results reveal that the multiple-mode property of the E-shaped resonator can be utilized in the UWB BPF design to achieve dual band-notched performance. To validate the design concept, a microstrip UWB BPF with two notched bands respectively centered at frequencies of 5.9 GHz and 8.0 GHz is designed and fabricated. Both simulation and experimental results are provided with good agreement. © 2013 IEEE.

Kuang F.,Nanjing University of Science and Technology | Kuang F.,Hunan Institute of Technology | Xu W.,Nanjing University of Science and Technology | Xu W.,Changsha University of Science and Technology | Zhang S.,Hunan Institute of Technology
Applied Soft Computing Journal | Year: 2014

A novel support vector machine (SVM) model combining kernel principal component analysis (KPCA) with genetic algorithm (GA) is proposed for intrusion detection. In the proposed model, a multi-layer SVM classifier is adopted to estimate whether the action is an attack, KPCA is used as a preprocessor of SVM to reduce the dimension of feature vectors and shorten training time. In order to reduce the noise caused by feature differences and improve the performance of SVM, an improved kernel function (N-RBF) is proposed by embedding the mean value and the mean square difference values of feature attributes in RBF kernel function. GA is employed to optimize the punishment factor C, kernel parameters σ and the tube size É of SVM. By comparison with other detection algorithms, the experimental results show that the proposed model performs higher predictive accuracy, faster convergence speed and better generalization. © 2014 Elsevier B.V.

Fang J.,Novartis | Zhou J.,Novartis | Fang Z.,Nanjing University of Science and Technology
RSC Advances | Year: 2013

An iridium-catalyzed hydrogen transfer reaction was successfully applied in the synthesis of 2-substituted quinazolines in moderate yields starting from aldehydes or alcohols with 2-aminobenzylamines. © 2013 The Royal Society of Chemistry.

Wei T.,Nanjing University of Science and Technology | Wei T.,Wenzhou Medical College | Zhu W.,Nanjing University of Science and Technology | Zhang J.,Wenzhou Medical College | Xiao H.,Nanjing University of Science and Technology
Journal of Hazardous Materials | Year: 2010

The heats of formation (HOFs) for a series of tetrazolo-[1,5-b]-1,2,4,5-tetrazine (TETZ) and 1,2,4-triazolo-[4,3-b]-1,2,4,5-tetrazine (TTZ) derivatives were studied by using density functional theory. The results show that the substitution of the -N3 or -N(NO2)2 group in the TETZ or TTZ ring extremely enhances its HOF values. For monosubstituted case, attachment of a substituent to position 8 in the TETZ or TTZ ring will increase its energy gaps except for the derivatives with the -NO2 group. It is also found that the energy gap of TTZ can be tuned by incorporating a substituent into different positions in the parent ring. The substitution of the -NH2 group in the TETZ ring is favorable for enhancing its thermal stability. For the TTZ ring, different substituted positions and number of the substituent might affect its thermal stability. The calculated detonation properties indicate that incorporating the -NO2, -NF2, -ONO2, or -N(NO2)2 group into the TETZ or TTZ ring is very helpful for enhancing its detonation performance. Considered the detonation performance and thermal stability, four derivatives may be regarded as the promising candidates of high-energy density materials (HEDMs). © 2010 Elsevier B.V.

He M.,Nanjing University of Science and Technology | Fries R.J.,Texas A&M University | Rapp R.,Texas A&M University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

Employing nonperturbative transport coefficients for heavy-flavor (HF) diffusion through quark-gluon plasma (QGP), hadronization and hadronic matter, we compute D- and B-meson observables in Pb+Pb (s=2.76TeV) collisions at the LHC. Elastic heavy-quark scattering in the QGP is evaluated within a thermodynamic T-matrix approach, generating resonances close to the critical temperature which are utilized for recombination into D and B mesons, followed by hadronic diffusion using effective hadronic scattering amplitudes. The transport coefficients are implemented via Fokker-Planck Langevin dynamics within hydrodynamic simulations of the bulk medium in nuclear collisions. The hydro expansion is quantitatively constrained by transverse-momentum spectra and elliptic flow of light hadrons. Our approach thus incorporates the paradigm of a strongly coupled medium in both bulk and HF dynamics throughout the thermal evolution of the system. At low and intermediate p T, HF observables at LHC are reasonably well accounted for, while discrepancies at high p T are indicative for radiative mechanisms not included in our approach. © 2014 The Authors.

Shi L.,Huaihai Institute of Technology | Li X.,Nanjing University of Science and Technology
Journal of Luminescence | Year: 2011

ZnO/SiO2 thin films were fabricated on Si substrates by E-beam evaporation with thermal retardation. The as-prepared films were annealed for 2 h every 100 °C in the temperature range 400800 °C under ambient air. The structural and optical properties were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL). The XRD analysis indicated that all ZnO thin films had a highly preferred orientation with the c-axis perpendicular to the substrate. From AFM images (AFM scan size is 1 μm×1 μm), the RMS roughnesses of the films were 3.82, 5.18, 3.65, 3.40 and 13.2 nm, respectively. PL measurements indicated that UV luminescence at only 374 nm was observed for all samples. The optical quality of the ZnO film was increased by thermal retardation and by using an amorphous SiO2 buffer layer. © 2010 Elsevier B.V. All rights reserved.

Ma L.,Nanjing University of Science and Technology | Wang Z.,Brunel University | Bo Y.,Nanjing University of Science and Technology | Guo Z.,Nanjing University of Science and Technology
Systems and Control Letters | Year: 2011

This paper is concerned with the mixed ℋ2/ ℋH∞ control problem for a class of stochastic time-varying systems with nonlinearities. The nonlinearities are described by statistical means and could cover several kinds of well-studied nonlinearities as special cases. The occurrence of the addressed nonlinearities is governed by two sequences of Bernoulli distributed white sequences with known probabilities. Such nonlinearities are named as randomly occurring nonlinearities (RONs) as they appear in a probabilistic way. The purpose of the problem under investigation is to design a controller such that the closed-loop system achieves the expected ℋ2 performance requirements with a guaranteed ℋH∞ disturbance attenuation level. A sufficient condition is given for the existence of the desired controller by means of solvability of certain coupled matrix equations. By resorting to the game theory approach, an algorithm is developed to obtain the controller gain at each sampling instant. A numerical example is presented to show the effectiveness and applicability of the proposed method. © 2011 Elsevier B.V. All rights reserved.

Ma L.,Nanjing University of Science and Technology | Wang Z.,Brunel University | Bo Y.,Nanjing University of Science and Technology | Guo Z.,Nanjing University of Science and Technology
International Journal of Robust and Nonlinear Control | Year: 2012

In this paper, an H ∞ sliding mode control (SMC) problem is studied for a class of discrete-time nonlinear stochastic systems with multiple data packet losses. The phenomenon of data packet losses, which is assumed to occur in a random way, is taken into consideration in the process of data transmission through both the state-feedback loop and the measurement output. The probability for the data packet loss for each individual state variable is governed by a corresponding individual random variable satisfying a certain probabilistic distribution over the interval [0 1]. The discrete-time system considered is also subject to norm-bounded parameter uncertainties and external nonlinear disturbances, which enter the system state equation in both matched and unmatched ways. A novel stochastic discrete-time switching function is proposed to facilitate the sliding mode controller design. Sufficient conditions are derived by means of the linear matrix inequality (LMI) approach. It is shown that the system dynamics in the specified sliding surface is exponentially stable in the mean square with a prescribed H ∞ noise attenuation level if an LMI with an equality constraint is feasible. A discrete-time SMC controller is designed capable of guaranteeing the discrete-time sliding mode reaching condition of the specified sliding surface with probability 1. Finally, a simulation example is given to show the effectiveness of the proposed method. © 2011 John Wiley & Sons, Ltd.

Xu S.,Nanjing University of Science and Technology | Feng G.,Nanjing University of Science and Technology | Feng G.,City University of Hong Kong | Zou Y.,Nanjing University of Science and Technology | And 2 more authors.
IEEE Transactions on Automatic Control | Year: 2012

This technical note deals with the problem of robust controller design of uncertain discrete time-delay systems subject to control input saturation and bounded external disturbances. A sufficient condition is obtained, which guarantees the existence of state feedback controllers and an admissible initial condition domain such that the resulting closed-loop system is uniformly exponentially convergent to a ball with certain exponential decay rate for every initial condition emanating from the admissible domain. An iterative linear matrix inequality relaxation scheme can be used to construct desired state feedback controllers. A simulation example is provided to demonstrate the effectiveness of the proposed method. © 1963-2012 IEEE.

Tao W.,Nanjing University of Science and Technology | Liu T.,Kochi University of Technology | Zheng R.,University of Tokyo | Feng H.,Nanjing University of Science and Technology
Sensors | Year: 2012

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. © 2012 by the authors.

Xin Y.,Nanjing University of Science and Technology | He Y.,Guangdong University of Petrochemical Technology | Chen Y.,Nanjing University of Science and Technology | Li J.,Nanjing University of Science and Technology
Optics Letters | Year: 2010

The correlation between intensity fluctuations of light scattered from a quasi-homogeneous random media was analytically derived. We showed the correlation depends on spatial Fourier transforms of both the intensity and degree of spatial correlation of scattering potentials of the media, while the normalized correlation equals the squared modulus of the degree of spatial coherence of the scattered fields. © 2010 Optical Society of America.

He M.,Nanjing University of Science and Technology | Fries R.J.,Texas A&M University | Rapp R.,Texas A&M University
Physical Review C - Nuclear Physics | Year: 2015

We calculate open heavy-flavor (HF) production in Au+Au collisions at sNN=62.4 GeV utilizing a nonperturbative transport approach as previously applied in nuclear collisions at top Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. The effects of hot QCD matter are treated in a strong-coupling framework, by implementing heavy-quark diffusion, hadronization, and heavy-flavor meson diffusion within a hydrodynamic background evolution. Since in our approach the heavy-flavor coupling to the medium is strongest in the pseudocritical region (including the effects of resonance recombination), it is of interest to test its consequences at lower collision energies where the sensitivity to this region should be enhanced relative to the initially hotter fireball temperatures reached at top RHIC and LHC energies. We find that the suppression and flow pattern of the nonphotonic electrons from heavy-flavor decays at 62.4 GeV emerges from an intricate interplay of thermalization and initial-state effects, in particular a Cronin enhancement which is known to become more pronounced toward lower collision energies. © 2015 American Physical Society.

Rapp R.,Texas A&M University | van Hees H.,FIAS | van Hees H.,Institute for Theoretical Physics | He M.,Nanjing University of Science and Technology
Nuclear Physics A | Year: 2014

We study the emission characteristics of thermal photons at RHIC and LHC as affected by both the space-time evolution of the bulk medium and the thermal emission rates. For the former we compare the results of two evolution models (expanding fireball and hydrodynamics). For the latter, we detail the influence of hadronic emission components and study a speculative scenario by upscaling the default QGP and hadronic rates around the pseudo-critical region. © 2014 Elsevier B.V.

Li L.,Nanjing University of Science and Technology | Zhong Q.,Delta Electronics Inc
IEEE Transactions on Industrial Electronics | Year: 2012

In this paper, a novel Zeta-mode three-level ac direct converter is proposed. The converter realizes three-level voltage waveforms before the output filter, which can get a better harmonic spectrum and reduce the bulk of the filter. Compared with two-level ac choppers, voltage stresses of the converter can be lowered. Compared with ac-dc-ac converters with no isolation and low- or middle-frequency isolation, the converter has single power stage and bidirectional power flow. Moreover, compared with buck-mode three-level ac choppers, it can realize buck and boost output voltage. The converter has four operation states in one period of input voltage and three different operation modes in one switching period. To ensure that the converter operates reliably, the noncomplementary control strategy is presented, which can make the converter switch smoothly between different modes in bidirectional power flow. Therefore, the converter is suitable to different kinds of loads. Principle analysis and experiment results of the prototype well verify the advantages of the proposed converter. © 2011 IEEE.

Zhang Z.,Qufu Normal University | Zhang Z.,Key Laboratory of System Control and Information Processing | Xu S.,Nanjing University of Science and Technology | Zhang B.,Nanjing University of Science and Technology
IEEE Transactions on Automatic Control | Year: 2014

This technical note is concerned with the problem of adaptive tracking control for a class of nonlinear systems with parametric uncertainty, unknown actuator nonlinearity and bounded external disturbance. Two type of actuator nonlinearities, that is, symmetric dead-zone and Bouc-Wen hysteresis, are considered, respectively. First, an adaptive control scheme with positive integrable time-varying function is presented to compensate for the dead-zone nonlinearity. Then, the actuator nonlinearity under consideration is modeled as Bouc-Wen hysteresis, and desired compensation controller is designed based on the backstepping technique and Nussbaum gain approach. In both of the two schemes, the asymptotic tracking is guaranteed with the tracking error converging to zero. Finally, an illustrative example is provided to show the effectiveness of the proposed design methods. © 1963-2012 IEEE.

Xiang H.J.,Fudan University | Xiang H.J.,National Renewable Energy Laboratory | Huang B.,National Renewable Energy Laboratory | Kan E.,Nanjing University of Science and Technology | And 2 more authors.
Physical Review Letters | Year: 2013

Diamond silicon (Si) is the leading material in the current solar cell market. However, diamond Si is an indirect band gap semiconductor with a large energy difference (2.3 eV) between the direct gap and the indirect gap, which makes it an inefficient absorber of light. In this work, we develop a novel inverse band structure design approach based on the particle swarming optimization algorithm to predict the metastable Si phases with better optical properties than diamond Si. Using our new method, we predict a cubic Si 20 phase with quasidirect gaps of 1.55 eV, which is a promising candidate for making thin-film solar cells. © 2013 American Physical Society.

Tan H.,Nanjing University of Science and Technology | Gao X.,Nanjing University of Science and Technology | Sun J.,Nanjing University of Science and Technology | Xiao C.,Nanjing University of Science and Technology | Hu X.,Jinling Institute of Technology
Chemical Communications | Year: 2013

A double stimulus-sensing platform based on a biopolymer hydrogel was developed for inducing stem cell aggregation and subsequent release. Our work will bring up a novel methodology to generate smart scaffolds with tailorable properties for biomedical applications. © 2013 The Royal Society of Chemistry.

Chen Y.,CAS Dalian Institute of Chemical Physics | Chen Y.,Nanjing University of Science and Technology | Wang F.,CAS Dalian Institute of Chemical Physics | Zhen W.,CAS Dalian Institute of Chemical Physics | Li X.,CAS Dalian Institute of Chemical Physics
Advanced Synthesis and Catalysis | Year: 2013

The rhodium(III)-catalyzed coupling of azomethine ylides with alkynes via C-H activation has been developed for the synthesis of indenamines in moderate to high yields. The coupled products can be further oxidized to indenones and derivatives. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiang H.J.,Fudan University | Kan E.J.,Nanjing University of Science and Technology | Wei S.-H.,National Renewable Energy Laboratory | Whangbo M.-H.,North Carolina State University | Gong X.G.,Fudan University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

A novel general method of describing the spin-lattice interactions in magnetic solids is proposed in terms of first-principles calculations. The spin exchange and Dzyaloshinskii-Moriya interactions, as well as their derivatives with respect to atomic displacements, can be evaluated efficiently on the basis of density-functional calculations for four ordered spin states. By taking into consideration the spin-spin interactions, the phonons, and the coupling between them, we show that the ground-state structure of a representative spin-frustrated spinel, MgCr 2O 4, is tetragonally distorted, in agreement with experiments. However, our calculations find the lowest energy for the collinear spin ground state, in contrast to previously suggested noncollinear models. © 2011 American Physical Society.

Kan E.,Nanjing University of Science and Technology | Li M.,Nanjing University of Science and Technology | Hu S.,Uppsala University | Xiao C.,Nanjing University of Science and Technology | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2013

Two-dimensional materials have been the hot subject of studies due to their great potential in applications. However, their applications in spintronics have been blocked by the difficulty in producing ordered spin structures in 2D structures. Here we demonstrated that the ultrathin films of recently experimentally realized wurtzite MnO can automatically transform into a stable graphitic structure with ordered spin arrangement via density functional calculation, and the stability of graphitic structure can be enhanced by external strain. Moreover, the antiferromagnetic ordering of graphitic MnO single layer can be switched into half-metallic ferromagnetism by small hole-doping, and the estimated Curie temperature is higher than 300 K. Thus, our results highlight a promising way toward 2D magnetic materials. © 2013 American Chemical Society.

Chen F.,Nanjing University of Science and Technology | Hu W.,Jiangsu Academy of Environmental Sciences | Zhong Q.,Nanjing University of Science and Technology
Atmospheric Research | Year: 2013

Real-world vehicle emission factors for PM10 (particulate matter with aerodynamic diameter smaller than 10μm) and particle-phase polycyclic aromatic hydrocarbons (PAHs) from mixed vehicles were quantified in the Fu Gui-shan Tunnel of Nanjing during summer and winter of 2010. Concentrations of PM10 and sixteen particle phase polycyclic aromatic hydrocarbons (PAHs) in the entrance and exit of the tunnel were studied. The results showed that the four most abundant particular phase polycyclic aromatic hydrocarbons (PAHs) of motor vehicle were benzo[ghi]perylene, benzo[k]fluoranthene, benz[a]anthracene and benzo[a]pyrene. The emission factors for PM10 and particle-phase PAHs were 687mgveh-1km-1 and 18.853mgveh-1km-1 in summer, 714mgveh-1km-1 and 20.374mgveh-1km-1 in winter. Higher particle-phase PAH emission factors were found to be associated with a high proportion of diesel-fueled vehicles (DV). The estimated PM10 emission factor of gasoline-fueled vehicles (GV) was 513mgveh-1km-1 and the value for DV was 914mgveh-1km-1, while EFDV of particulate PAH (31.290mgveh-1km-1) was nearly 4 times higher than EFGV (9.310mgveh-1km-1). The five highest emission factors of diesel-fueled vehicles (DV) were benzo[ghi]perylene, benzo[k]fluoranthene, Indeno[1,2,3-cd]pyrene, benz[a]anthracene and benzo[a]pyrene, which was similarly found in the gasoline-fueled vehicles (GV). The sum of these five emission factors accounted for ~69% of the total particle-phase PAH of DV and ~67% of GV. © 2013 Elsevier B.V.

Tan H.,Nanjing University of Science and Technology | Xiao C.,Nanjing University of Science and Technology | Sun J.,Nanjing University of Science and Technology | Xiong D.,Nanjing University of Science and Technology | Hu X.,Jinling Institute of Technology
Chemical Communications | Year: 2012

A biological hydrogel was self-assembled via Watson-Crick base pairing of thymine and adenine from functionalized star poly(ethylene glycol). Our work should provide a novel methodology to generate robust injectable scaffolds with tailorable properties for biomedical applications. © 2012 The Royal Society of Chemistry.

Xiong R.,PLA University of Science and Technology | Chen B.,PLA University of Science and Technology | Fang D.,Nanjing University of Science and Technology
IEEE Transactions on Antennas and Propagation | Year: 2014

A sub-cell algorithm for the finite-difference time-domain (FDTD) modeling of flat electrode in grounding systems is proposed. The electromagnetic field variation near a flat electrode is derived from the integral of the differential electric field which is radiated by the distributed charge on an electrostatic charged flat electrode. By fully incasing the field singularity into the coarse cells containing the electrode with the Faraday's Law, a sub-cell algorithm has been proposed to reduce computational resources when modeling the flat electrode. The accuracy of the derived field singularity is verified from comparison with the field given by the high-resolution standard FDTD simulation. The efficiency of the proposed algorithm has been approved by verifying the transient grounding resistance (TGR) of the grounding system using the proposed algorithm and the computational memory and time usage. © 2013 IEEE.

Xiang H.J.,Fudan University | Kan E.J.,Nanjing University of Science and Technology | Zhang Y.,North Carolina State University | Whangbo M.-H.,North Carolina State University | Gong X.G.,Fudan University
Physical Review Letters | Year: 2011

The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained by any existing model of magnetic-order-driven ferroelectricity. We resolve this problem by developing a general theory for the ferroelectric polarization induced by spin-spiral order and then by evaluating the coefficients needed to specify the general theory on the basis of density functional calculations. Our theory correctly describes the ferroelectricity of triangular-lattice antiferromagnets driven by helical spin-spiral order and incorporates known models of magnetic-order-driven ferroelectricity as special cases. © 2011 American Physical Society.

Tan H.,Nanjing University of Science and Technology | Hu X.,Jinling Institute of Technology
Journal of Applied Polymer Science | Year: 2012

An injectable and glucose-responsive hydrogel derived from dextran derivatives and lectin concanavalin A (ConA) was synthesized to deliver adipogenic factor for adipose tissue engineering. The gelation is attributed to the Schiff-base reaction cross-linking between aldehydic and aminated dextran. To enhance adipogenesis, the adipogenic factor of insulin was incorporated in the ConA immobilized hydrogels. The gelation time, compressive modulus, morphologies, weight loss, and swelling properties of the hydrogels were investigated. The ConA triggered a competitive displacement of dextran by glucose from the lectin receptor sites, and results in increasing swelling of the gel network. The swelling ratio (SR) of ConA immobilized hydrogel showed glucose dependent properties and linearly increased from 19.8 to 31.3 at 37°C in PBS at glucose concentrations between 0 and 1.0% (w/v). The in vitro release experiments showed that the insulin would be released from this dextran hydrogel into the local microenvironment in response to glucose, thus highlighting the potential of such a injectable and biodegradable hydrogel to be used as part of implantable scaffold to delivery adipogenic factor for adipose tissue engineering. © 2012 Wiley Periodicals, Inc.

Chen Y.,CAS Dalian Institute of Chemical Physics | Chen Y.,Nanjing University of Science and Technology | Wang F.,CAS Dalian Institute of Chemical Physics | Jia A.,Nanjing University of Science and Technology | Li X.,CAS Dalian Institute of Chemical Physics
Chemical Science | Year: 2012

Substrate-controlled selective oxidative olefination of N-protected 2-pyridones has been achieved under palladium catalysis. The 5-position selectivity was followed for N-protected simple pyridones. Introduction of substituents into the 4- or the 6-position switched the site selectivity to the 3-position. Diolefination can also be achieved with high efficiency. Oxidative arylation with polyfluorobenzenes followed a similar selectivity except that the system is more sterically and electronically demanding. © 2012 The Royal Society of Chemistry.

Zhang X.,Nanjing University | Zhang X.,CAS Dalian Institute of Chemical Physics | Chen D.,CAS Dalian Institute of Chemical Physics | Chen D.,Nanjing University of Science and Technology | And 4 more authors.
Advanced Synthesis and Catalysis | Year: 2011

Isoquinolines have been synthesized from the redox-neutral dehydrative C-N and C-C cross-coupling between oximines and alkynes using a catalytic amount of (pentamethylcyclopentadiene)rhodium dichloride dimer {[RhCp*Cl 2]2} and cesium acetate (CsOAc), a process that involves ortho C-H activation of oximines and subsequent functionalization with alkynes. This redox-neutral catalytic isoquinoline synthesis operates under mild conditions, and is insensitive to moisture or air. A broad scope of coupling partners has been established, and a likely mechanism has been suggested. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiang Z.,Nanjing University of Science and Technology | Wang R.,PLA University of Science and Technology
Transactions of the Institute of Measurement and Control | Year: 2010

This paper considers the problem of stability and robust H ∞ stabilization for a class of uncertain switched systems using the delta operator. Based on multiple Lyapunov function method, a sufficient condition for the existence of stability of the delta operator switched system is presented, and the design approach to robust H∞ state feedback controller is addressed. The proposed controller can robustly stabilize the uncertain delta operator switched system, and also guarantee H ∞ performance of the closed-loop system for all admissible parameter perturbations. The solution to the controller is formulated in the form of a set of linear matrix inequalities. A numerical example is provided to illustrate the effectiveness of the developed method. © 2010 The Institute of Measurement and Control.

Dai J.,Jiangsu University | Xu X.,Nanjing University of Science and Technology | Zhao D.,Jiangsu University
IEEE Antennas and Wireless Propagation Letters | Year: 2013

Sparse representation direction-of-arrival (DOA) estimation methods exhibit many advantages over other DOA estimation methods. However, they suffer from a high computational complexity. This letter describes a real-valued sparse representation method through utilizing a unitary transformation that can convert complex-valued manifold matrices of uniform linear arrays (ULAs) into real ones. Due to this transformation, the computational complexity is decreased by a factor of at least four. The letter also shows that the proposed method has a better noise suppression because of exploiting an additional real structure. Therefore, it outperforms the original method, especially when signal-to-noise ratio (SNR) is low. Simulation results verify the performance improvement of the proposed method. © 2002-2011 IEEE.

Cui L.,Nanjing University of Science and Technology | Wu W.,Nanjing University of Science and Technology | Fang D.-G.,Nanjing University of Science and Technology
IEEE Antennas and Wireless Propagation Letters | Year: 2013

A frequency beam-scanning antenna with backfire-to-endfire beam-steering capability is proposed and investigated. This antenna is with printed planar structure that consists of a low-loss slow-wave printed meander line based on the even-mode bilateral broadside-coupled suspended microstrip line (BSML). The propagation properties of the meander-line unit and its principles for frequency-scanning applications are studied extensively. This printed antenna achieves the measured beam scanning of-27.5° to 46° with the frequency sensitivity of 43.24°/GHz and a maximum gain of 15.5 dBi. The antenna exhibits flat gain of more than 13 dBi in the whole frequency range from 8.9 to 10.6 GHz. The sidelobe levels are near 20 dB. The design flexibility of this kind of antenna is shown. © 2002-2011 IEEE.