热点成果rss-机构知识库http:www.notefist.com科研成功热点成果rssMechanically stretchable and tunable metamaterial absorberhttp://ir.nwpu.edu.cn/AchivementDetails/Index/181Zhang, Fuli;Feng, Shuqi;Qiu, Kepeng,等2016/11/25 15:34:42In this letter, we present experimental demonstration of a mechanically stretchable and tunable metamaterial absorber composed of dielectric resonator stacked on a thin conductive rubber layer. A near unity absorption is observed due to strong local field confinement around magnetic Mie resonance of dielectric resonator. Furthermore, the interspacing between unit cells is modulated dynamically under uniaxial stress. Owing to the decreases of longitudinal coupling between neighboring unit cells, the resonant absorption peak is reversibly tuned by 410 MHz, as the stain varies up to 180% along H field direction. On the contrary, the resonant absorption state is nearly independent on strain variation when external stress is applied along E field direction, due to the weak transverse interplaying. The mechanically tunable metamaterial absorber featured by flexibility paves a way forwards for actual application. (C) 2015 AIP Publishing LLC.APPLIED PHYSICS LETTERS20151069APPLIED PHYSICS LETTERS,2015,106(9)Tunable Terahertz Meta-Surface with Graphene Cut-Wireshttp://ir.nwpu.edu.cn/AchivementDetails/Index/570Fan, Yuancheng;Shen, Nian-Hai;Koschny, Thomas,等2016/11/25 15:34:57We propose a tunable meta-surface in the terahertz regime by Patterning a graphene sheet in cut-wire array. The enhancement of terahertz absorption of such a graphene meta-surface was studied detailedly via the optimization to the geometry of the structure. Considering the data of graphene in both the experimental and theoretical perspectives, we investigated the performance of the absorbing graphene meta-surface by extracting its effective surface conductivities through a sheet retrieval method. We also specifically considered two sets of well-known experimental graphene data and comparatively studied the properties of graphene meta-surface by changing the graphene parameters in-between. It shows that there has been significant improvement in preparing high-quality graphene samples, which makes it possible to strengthen optical properties of graphene microstructures, and therefore benefits various practical applications.ACS PHOTONICS201521151-156ACS PHOTONICS,2015,2(1):151-156Synthesis, characterization and excellent electromagnetic wave absorption properties of graphene/poly (3,4-ethylenedioxythiophene) hybrid materials with Fe3O4 nanoparticleshttp://ir.nwpu.edu.cn/AchivementDetails/Index/682Liu, Panbo;Huang, Ying;Zhang, Xiang2016/11/25 15:34:57The electromagnetic wave absorption properties of the ternary nanocomposites consisting of graphene, poly (3,4-ethylenedioxythiophene) and Fe3O4 nanoparticles had never been reported. Herein, in order to expand the scope of electromagnetic wave absorption materials, the nanostructured graphene/poly (3,4-ethylenedioxythiophene) hybrid materials with Fe3O4 nanoparticles had been synthesized by a controllable co-precipitation method. The nanocomposites were characterized by FTIR, XRD, TEM, Raman spectroscopy, XPS and TG analysis. The investigation of the electromagnetic parameters revealed that the excellent electromagnetic wave absorption properties of the nanocomposites may be attributed to the improved impedance matching, the enhanced interfacial effects and the geometric effect. The maximum reflection loss of the nanocomposites was up to -56.5 dB at 8.9 GHz and the absorption bandwidths exceeding -10 dB were 3 GHz with a thickness of 2.9 mm. Furthermore, our development strategies expanded the scope of the electromagnetic wave absorption materials and confirmed that the modification of graphene with poly (3,4-ethylenedioxythiophene) and Fe3O4 nanoparticles makes the nanocomposites have a promising future in electromagnetic wave absorption materials. (C) 2014 Elsevier B.V. All rights reserved.JOURNAL OF ALLOYS AND COMPOUNDS2014617511-517JOURNAL OF ALLOYS AND COMPOUNDS,2014,617:511-517Tunable terahertz coherent perfect absorption in a monolayer graphenehttp://ir.nwpu.edu.cn/AchivementDetails/Index/933Fan, Yuancheng;Zhang, Fuli;Zhao, Qian,等2016/11/25 15:34:57Coherent perfect absorber (CPA) was proposed as the time-reversed counterpart to laser: a resonator containing lossy medium instead of gain medium can absorb the coherent optical fields completely. Here, we exploit a monolayer graphene to realize the CPA in a nonresonant manner. It is found that quasi-CPA point exists in the terahertz regime for suspending monolayer graphene, and the CPA can be implemented with the assistance of proper phase modulation among two incident beams at the quasi-CPA frequencies. The graphene-based CPA is found of broadband angular selectivity: CPA point splits into two frequency bands for the orthogonal s and p polarizations at oblique incidence, and the two bands cover a wide frequency range starting from zero frequency. Furthermore, the coherent absorption can be tuned substantially by varying the gate-controlled Fermi energy. The findings of CPA with nonresonant graphene sheet can be generalized for potential applications in terahertz/infrared detections and signal processing with two-dimensional optoelectronic materials. (C) 2014 Optical Society of AmericaOPTICS LETTERS201439216269-6272OPTICS LETTERS,2014,39(21):6269-6272Formation mechanism of banded structure during directional solidification of Sn-Cd peritectic alloy under convection conditionhttp://ir.nwpu.edu.cn/AchivementDetails/Index/2055Wang, Lingshui;Shen, Jun;Wang, Lei,等2016/11/25 15:35:36Directional solidification experiments of Sn-0.75 wt%Cd and Sn-1.6 wt%Cd peritectic alloys have been conducted under convection condition to investigate the formation mechanism of banded structure. Many types of banded structure were obtained, which cannot be interpreted by the Karma's model. The reason for this conflict is that there are many banded structure formation mechanisms such as abundant nucleation, regrowth, fast radial cellular growth and radial competitive growth under convection condition, but the Karma's model only considers the abundant nucleation and ignores other mechanisms. The analyses showed that these formation mechanisms changed along with an increase in alloy composition. Based on these analyses, a simple modified banding window, which considered these different formation mechanisms, has been presented. Compared with the banding window defined by the Karma's model, this modified banding window contained it and could predict different banded structure formations under convection condition appropriately.APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING20141143769-776APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING,2014,114(3):769-776Reinforcement Learning Output Feedback NN Control Using Deterministic Learning Techniquehttp://ir.nwpu.edu.cn/AchivementDetails/Index/2071Xu, Bin;Yang, Chenguang;Shi, Zhongke2016/11/25 15:35:36In this brief, a novel adaptive-critic-based neural network (NN) controller is investigated for nonlinear pure-feedback systems. The controller design is based on the transformed predictor form, and the actor-critic NN control architecture includes two NNs, whereas the critic NN is used to approximate the strategic utility function, and the action NN is employed to minimize both the strategic utility function and the tracking error. A deterministic learning technique has been employed to guarantee that the partial persistent excitation condition of internal states is satisfied during tracking control to a periodic reference orbit. The uniformly ultimate boundedness of closed-loop signals is shown via Lyapunov stability analysis. Simulation results are presented to demonstrate the effectiveness of the proposed control.IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS2014253635-641IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS,2014,25(3):635-641Elastic flexural and torsional buckling behavior of pre-twisted bar under axial loadhttp://ir.nwpu.edu.cn/AchivementDetails/Index/2236Chen, Chang Hong;Yao, Yao;Huang, Ying2016/11/25 15:35:36According to deformation features of pre-twisted bar, its elastic bending and torsion buckling equation is developed in the paper. The equation indicates that the bending buckling deformations in two main bending directions are coupled with each other, bending and twist buckling deformations are coupled with each other as well. However, for pre-twisted bar with dual-axis symmetry cross-section, bending buckling deformations are independent to the twist buckling deformation. The research indicates that the elastic torsion buckling load is not related to the pre-twisted angle, and equals to the torsion buckling load of the straight bar. Finite element analysis to pre-twisted bar with different pre-twisted angle is performed, the prediction shows that the assumption of a plane elastic bending buckling deformation curve proposed in previous literature (Shadnam and Abbasnia 2002) may not be accurate, and the curve deviates more from a plane with increasing of the pre-twisting angle. Finally, the parameters analysis is carried out to obtain the relationships between elastic bending buckling critical capacity, the effect of different pre-twisted angles and bending rigidity ratios are studied. The numerical results show that the existence of the pre-twisted angle leads to "resistance" effect of the stronger axis on buckling deformation, and enhances the elastic bending buckling critical capacity. It is noted that the "resistance" is getting stronger and the elastic buckling capacity is higher as the cross section bending rigidity ratio increases.STRUCTURAL ENGINEERING AND MECHANICS2014492273-283STRUCTURAL ENGINEERING AND MECHANICS,2014,49(2):273-283Characteristics and mechanisms of 4A zeolite supported nanoparticulate zero-valent iron as Fenton-like catalyst to degrade methylene bluehttp://ir.nwpu.edu.cn/AchivementDetails/Index/2327Wu, Yaoguo;Yang, Mengchen;Hu, Sihai,等2016/11/25 15:35:364A zeolite supported nanoparticulate zero-valent iron (nZVI/4A zeolite), synthesized through borohydride reduction method, was used as a catalyst with H2O2 to build Fenton-like reaction system to degrade methylene blue (MB) in model wastewater. The characteristics and primary mechanisms of the catalyst were investigated. The results show that nZVI/4A zeolite has the potential as a Fenton-like catalyst, and (about 30 mg/L) MB was degraded completely in 3 h with 10 mM H2O2, 0.2 g/L catalyst, and initial pH of 3.0. The MB degradation rates were obtained at least 70% in the tests with initial pH ranged from 2.0 to 9.0 and the catalyst dose rose from 0.2 to 5.0 g/L. Importantly, the catalyst also has a distinctive ability to increase the solution pH value from its initial acidic pH and then maintain the value at close to neutrality. This ability was controlled by both the initial pH and the catalyst dose. MB degradation clarified that hydroxyl radical was the dominated active oxidative specie in the tests with initial acidic pH and low catalyst dose (less 2.5 g/L); otherwise, Fe (VI) oxidation was the main mechanism for MB degradation; and the two processes shared synergistic effect in MB degradation in the present test. The catalyst has high operational stability in both of the composites with low iron leaching (less 2%) and catalyzing ability. Therefore, nZVI/4A zeolite has great potential as a Fenton-like catalyst and is used with H2O2 to build Fenton-like system which could be used to degrade MB efficiently.TOXICOLOGICAL AND ENVIRONMENTAL CHEMISTRY2014962227-242TOXICOLOGICAL AND ENVIRONMENTAL CHEMISTRY,2014,96(2):227-242Synthesis and microwave absorption enhancement of graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structureshttp://ir.nwpu.edu.cn/AchivementDetails/Index/2443Wang, Lei;Huang, Ying;Sun, Xu,等2016/11/25 15:35:36Hierarchical structures of graphene@Fe3O4@SiO2@NiO nanosheets were prepared by combining the versatile sol-gel process with a hydrothermal reaction. Graphene@Fe3O4 composites were first synthesized by the reduction reaction between FeCl3 and diethylene glycol (DEG) in the presence of GO. Then, graphene@Fe3O4 was coated with SiO2 to obtain graphene@Fe3O4@SiO2. Finally, NiO nanosheets were grown perpendicularly on the surface of graphene@Fe3O4@SiO2 and graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures were formed. Moreover, the microwave absorption properties of both graphene@Fe3O4 and graphene@Fe3O4@SiO2@NiO nanosheets were investigated between 2 and 18 GHz microwave frequency bands. The electromagnetic data demonstrate that graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures exhibit significantly enhanced microwave absorption properties compared with graphene@Fe3O4, which probably originate from the unique hierarchical structure with a large surface area and high porosity.NANOSCALE2014663157-3164NANOSCALE,2014,6(6):3157-3164Facile synthesis and performance of polypyrrole-coated hollow Zn2SnO4 boxes as anode materials for lithium-ion batterieshttp://ir.nwpu.edu.cn/AchivementDetails/Index/2489Wang, Ke;Huang, Ying;Han, Tiaozheng,等2016/11/25 15:35:36Polypyrrole-coated hollow Zn2SnO4 boxes (hollow Zn2SnO4@PPY nanocomposites) had been prepared by a microemulsion polymerization. The structural, morphological and electrochemical properties were methodically investigated by means of XRD, TGA, BJH (pore size distribution analysis), SEM, TEM, and electrochemical measurements. Results show that the hollow Zn2SnO4 boxes with the uniform and cube like structure are coated by PPY. Electrochemical measurement suggests that hollow Zn2SnO4@PPY composites exhibit better cycling properties and lower initial irreversible capacities as anode materials for lithium-ion batteries. At a current density of 60 mA/g in the voltage about 0.01-3.0 V, the first discharge-charge capacities of hollow Zn2SnO4@PPY composites are 1105.2 mAh/g and 556 mAh/g. After 50 cycles, a specific charge capacity of 478.4 mAh/g remained and the coulombic efficiency reaches 98.2%, revealing better capacity retention compared with hollow Zn2SnO4 boxes. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.CERAMICS INTERNATIONAL20144012359-2364CERAMICS INTERNATIONAL,2014,40(1):2359-2364One-pot hydrothermal synthesis of RGO/CoFe2O4 composite and its excellent microwave absorption propertieshttp://ir.nwpu.edu.cn/AchivementDetails/Index/2569Zong, Meng;Huang, Ying;Wu, Haiwei,等2016/11/25 15:35:50Reduced graphene oxide (RGO)/CoFe2O4 composite was synthesized by a one-pot hydrothermal route, which avoided the usage of chemical reducing agent. The reduction of graphene oxide (GO) and the crystallization of CoFe2O4 crystals happened in a one step process by the hydrothermal method. The RGO/CoFe2O4 composite shows remarkably improved electromagnetic performance in comparison with CoFe2O4 NPs and reported pure RGO. Not only a larger reflection loss (-47.9 dB at 12.4 GHz), but also a wider absorption band (less than -10 dB from 12.4 to 17.4 GHz) has been achieved in the frequency range of 2-18 GHz. It is believed that such composites could be used as a candidate microwave absorber. (C) 2013 Elsevier B.V. All rights reserved.MATERIALS LETTERS201411452-55MATERIALS LETTERS,2014,114:52-55Preparation and electromagnetic properties of graphene-supported Ni0.8Zn0.2Ce0.06Fe1.94O4 nanocompositehttp://ir.nwpu.edu.cn/AchivementDetails/Index/2774Wang, Yan;Huang, Ying;Wang, Qiufen,等2016/11/25 15:35:50The graphene supported Ni0.8Zn0.2Ce0.06Fe1.94O4 nanocomposite was prepared by a deoxidation technique. The structure, morphology and electromagnetic properties of the composites were characterized by various instruments. The Ni0.8Zn0.2Ce0.06Fe1.94O4 powders could be distributed on the graphene sheets (GNS). The as-prepared Ni0.8Zn0.2Ce0.06Fe1.94O4/GNS nanocomposite exhibits a saturated magnetization of 50.42 emu/g. The electromagnetic parameters of NiasZno.2CeaosFeLs404/GNS nanocomposite were investigated in the 2-18 GHz range. The composite Ni0.8Zn0.2Ce0.06Fe1.94O4/GNS exhibits better microwave absorbing properties than Ni0.8Zn0.2Ce0.06Fe1.94O4. The minimum loss value of Ni0.8Zn0.2Ce0.06Fe1.94O4/GNS nanocomposite is 37.4 dB at 123 GHz and a broad peak with a bandwidth lower than 10 dB is at 10.7-152 GHz. These results show that the introduction of GNS can increase the complex permittivities and has an important effect on the improvement of microwave absorption properties. (C) 2013 Elsevier BV. All rights reserved.POWDER TECHNOLOGY2013249304-308POWDER TECHNOLOGY,2013,249:304-308Microstructure Investigation of Directionally Solidified NiAl-Cr(Mo)-xDy (x=0, 0.1 wt.%) Hypereutectic Alloys at Different Withdrawal Rateshttp://ir.nwpu.edu.cn/AchivementDetails/Index/2800Wang, Lei;Shen, Jun;Shang, Zhao,等2016/11/25 15:35:50The microstructures of directionally solidified Ni-31Al-32Cr-6Mo (at.%)-xDy (x = 0, 0.1 wt.%) hypereutectic alloys were studied at different withdrawal rates. The results show that the microstructure changes from the planar eutectic to the cellular eutectic and the volume fraction of the primary Cr(Mo) dendrites decreases for the Dy-free alloy with the withdrawal rate varying from 6 mu m/s to 30 mu m/s. The addition of 0.1 wt.% Dy promotes the planar-to-cellular transition. Moreover, the white Dy-containing phase does not form in the alloy for the planar interface growth (6 mu m/s), but it can occur in the boundary of eutectic cells for the cellular interface growth (30 mu m/s). A sketchy model of the planar and cellular growth is supposed to interpret it.JOM201365111419-1425JOM,2013,65(11):1419-1425Direct neural control of hypersonic flight vehicles with prediction model in discrete timehttp://ir.nwpu.edu.cn/AchivementDetails/Index/3004Xu, Bin;Wang, Danwei;Sun, Fuchun,等2016/11/25 15:35:50In this paper, the direct adaptive neural controller is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV). The objective of the controller is to make the altitude and velocity to follow a given desired trajectory in the presence of aerodynamic uncertainties. Based on the functional decomposition, the adaptive discrete-time nonlinear controllers are developed using feedback linearization and neural approximation for the two subsystems. Different from the back-stepping design, the altitude subsystem is transformed into the explicit four-step ahead prediction model. With the prediction model, the controller is proposed without virtual controller design. Furthermore, only one direct neural network (NN) is employed for the lumped system uncertainty approximation. The controller is considerably simpler than the ones based on back-stepping scheme and the algorithm needs less NN parameters to be adjusted online. The semiglobal uniform ultimate boundedness (SGUUB) stability is investigated by the discrete-time Lyapunov analysis and the output tracking error is made within a neighborhood of zero. Accordingly, the NN controller is designed for velocity subsystem. The simulation is presented to show the effectiveness of the proposed control approach. (C) 2013 Elsevier B.V. All rights reserved.NEUROCOMPUTING201311539-48NEUROCOMPUTING,2013,115:39-48Synthesis and electrochemical characterizations of Ce doped SnS2 anode materials for rechargeable lithium ion batterieshttp://ir.nwpu.edu.cn/AchivementDetails/Index/3668Wang, Qiufen;Huang, Ying;Miao, Juan,等2016/11/25 15:36:26The nanocomposites Ce doped SnS2 (Ce-SnS2) have been synthesized by a hydrothermal route. The Ce-SnS2 composites exhibit 3D flowerlike structures. The particle sizes of each petal are in the range from 100 to 200 nm with clear lattice fringes. The electrode cycling performance and rate retention ability of Ce-SnS2 are better than those of SnS2 as anode electrodes materials for lithium ion batteries. The Ce-SnS2 compound (Ce of 5 mol%) shows the best reversible capacities and cycling performance among the synthesized Ce-SnS2 compounds. The reason is that the part of large-radius cerium ions (much larger than that of Sn4+) can be the substitutes for Sn4+ in the SnS2 lattice. The expansion of the crystal lattice can provide more lattice space for lithium intercalation and de-intercalation, and further improves the cycling performance of Ce-SnSz. (C) 2013 Elsevier Ltd. All rights reserved.ELECTROCHIMICA ACTA201393120-130ELECTROCHIMICA ACTA,2013,93:120-130Unsteady simulation of a counter-rotating research compressor using the nonlinear harmonic methodhttp://ir.nwpu.edu.cn/AchivementDetails/Index/3697Wang, Lei;Liu, Bo;Yang, Xiaodong,等2016/11/25 15:36:26In this article, the nonlinear harmonic method implemented in Fine/Turbo code has been evaluated for unsteady rotor-rotor interaction analysis. Strengths and weaknesses of the nonlinear harmonic method are highlighted through direct comparison with experimental data and time-domain unsteady simulation for the Northwestern Polytechnical University counter-rotating research compressor at the design and off-design conditions. The rotor-rotor interactions were studied in detail to advance the understanding of the flow physics involved. Based on the unsteady simulation, deterministic stresses were computed and compared to the nonlinear harmonic method to analyze distinct sources of unsteadiness and their effect on the time-averaged flow field. For the present case, the nonlinear harmonic method efficiently computes unsteady flows and shows major improvements regarding the computational time (to a factor up to 10).PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING2013227G3415-424PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING,2013,227(G3):415-424Synthesis and microwave absorption enhancement of NiO nanosheets@SiO2@graphene hierarchical structureshttp://ir.nwpu.edu.cn/AchivementDetails/Index/3938Wang, Lei;Huang, Ying;Ding, Xiao,等2016/11/25 15:36:27Three kinds of NiO@SiO2@graphene hierarchical structures, NiO nanoparticles@SiO2@graphene, NiO nanosheets@SiO2@graphene and NiO nanoflowers@SiO2@graphene composites were successfully fabricated by multi-step routes. The measured electromagnetic parameters show that NiO nanosheets@SiO2@graphene composites exhibit enhanced microwave absorption performance with wide absorption bandwidth as compared to NiO nanoparticles@SiO2@graphene and NiO nanoflowers@SiO2@graphene. The maximum reflection loss can reach -43.8 dB at 11.6 GHz with a thickness of 3 mm, and the absorption bandwidth with the reflection loss below -10 dB is 5.8 GHz (from 9.2 to 15 GHz). In addition, the mechanisms for the enhanced absorption performance are also discussed.RSC ADVANCES201334523290-23295RSC ADVANCES,2013,3(45):23290-23295Facile preparation, high microwave absorption and microwave absorbing mechanism of RGO-Fe3O4 compositeshttp://ir.nwpu.edu.cn/AchivementDetails/Index/3940Zong, Meng;Huang, Ying;Zhao, Yang,等2016/11/25 15:36:27Reduced graphene oxide (RGO)-Fe3O4 composites with obviously enhanced microwave absorption properties were successfully fabricated by a rational one-pot simplified co-precipitation route, which avoided the usage of an inert gas and any additional chemical agents (such as surfactants and stabilizers). Given these advantages, the strategy described in this study can be developed as a simple and large-scale route to yield RGO-Fe3O4 composites. The morphology, structure, thermal stability, magnetic and microwave electromagnetic properties of the as-prepared composites were characterized by XRD, XPS, TEM, FT-IR, Raman, TG and VSM. These composites exhibit excellent microwave absorption properties, which are attributed to effective complementarities between the dielectric loss and the magnetic loss. The microwave absorption mechanism of the RGO-Fe3O4 composites was studied in detail. For the RGO-Fe3O4-3 composite, the maximum R-L reaches -44.6 dB at 6.6 GHz with a thickness of 3.9 mm, and the bandwidth of R-L less than -10 dB can reach up to 4.3 GHz (from 12.2 to 16.5 GHz) with a thickness of 2.0 mm. Moreover, the microwave absorption properties can be tuned easily by varying the (RGO)/(Fe3O4) ratio and layer thickness of the samples. It is believed that such composites will find wide applications in the microwave absorbing area.RSC ADVANCES201334523638-23648RSC ADVANCES,2013,3(45):23638-23648Transient electromagnetic S-inversion in tunnel predictionhttp://ir.nwpu.edu.cn/AchivementDetails/Index/9266Xue, G. Q.;Yan, Y. J.;Li, X.,等2016/11/25 15:40:20This paper presents S-inversion method to tunnel prediction to forecasting water-filled faults or fracture zones ahead of the front wall of a tunnel during tunnel excavation. S-inversion is an interpretation method of transient electromagnetic (TEM) data using the second derivative of the conductivity parameter based on the moving thin sheet approach. It is suggested for the technology of second derivative of vertical apparent conductivity, which is traditionally used in surface TEM data interpretation, the theoretical analyses and the method of numerical calculation in detail are also given. Finally, a real tunnel forecasting is studied for TEM surveys, and results show that the proposed method is effective and successful for exploring and predicting unfavorable geology during tunnel construction. Citation: Xue, G. Q., Y. J. Yan, X. Li, and Q. Y. Di ( 2007), Transient electromagnetic S-inversion in tunnel prediction, Geophys. Res. Lett., 34, L18403, doi: 10.1029/2007GL031080.GEOPHYSICAL RESEARCH LETTERS20073418GEOPHYSICAL RESEARCH LETTERS,2007,34(18)Experimental validation of vibration-based damage detection for static laminated composite shells partially filled with fluidhttp://ir.nwpu.edu.cn/AchivementDetails/Index/9433Yu, L.;Cheng, L.;Yam, L. H.,等2016/11/25 15:40:21A vibration-based damage detection method for a static laminated composite shell partially filled with fluid (LCSFF) is presented and validated by experiment. The crack damage is simulated using advanced composite damage mechanics in a dynamic finite element model, in which the interaction between the fluid and the composite shell is considered. The accuracy of FE model is first validated by comparing the computed and measured structural frequency response function. Structural damage indexes are constructed and calculated based on energy variation of the structural vibration responses decomposed using wavelet package before and after the occurrence of structural damage. An artificial neural network (ANN) is trained using numerically simulated structural damage index to establish the mapping relationship between the structural damage index and damage status. The test specimen used in experiment contains a cut in its surface made by laser cutting system. Response signals of both intact and damaged specimen are measured and used to construct the corresponding damage indices. The damage status is successfully identified using ANN, indicating that the method adopted in this paper can be applied to online structural damage detection and health monitoring for static LCSFF. (C) 2006 Elsevier Ltd. All rights reserved.COMPOSITE STRUCTURES2007792288-299COMPOSITE STRUCTURES,2007,79(2):288-299Development in vibration-based structural damage detection techniquehttp://ir.nwpu.edu.cn/AchivementDetails/Index/9450Yan, Y. J.;Cheng, L.;Wu, Z. Y.;Yam, L. H.2016/11/25 15:40:21This paper presents a general summary and review of state-of-the-art and development of vibration-based structural damage detection. Various structural damage detection methods based on structural dynamic characteristic parameters are summarised and evaluated. The principle of intelligent damage diagnosis and its application prospects in structural damage detection are introduced, and the development trends of structural damage detection are also put forward. (c) 2006 Elsevier Ltd. All rights reserved.MECHANICAL SYSTEMS AND SIGNAL PROCESSING20072152198-2211MECHANICAL SYSTEMS AND SIGNAL PROCESSING,2007,21(5):2198-2211Application of eigenvalue perturbation theory for detecting small structural damage using dynamic responseshttp://ir.nwpu.edu.cn/AchivementDetails/Index/9554Yu, L.;Cheng, L.;Yam, L. H.,等2016/11/25 15:40:21Current methods for structural damage identification, such as genetic algorithms and artificial neural networks, are often implemented based on a few measured data and a large number of simulation data. The tremendous time-consuming computational work needed for calculating the response data to establish the dynamic model of damaged structures is an important issue for dynamic damage detection. In this paper through using the advanced modeling method of element stiffness matrix modification, the order of the global stiffness matrix can be kept invariable in establishing the model of intact and damaged structures. Then, eigenvalue perturbation theory is introduced to obtain the eigenvalues and eigenvectors of the damaged structure for reducing the computation load. Two artificial neural networks (ANN) are trained based on the response data simulated using finite element method (FEM) and perturbation theory enhanced finite element method (PFEM), respectively. The damage identification capability of these two ANN's are compared. Results show that the PFEM using the first order eigenvalue perturbation theory provides enough precision for detecting small structural damage and the computational requirement is greatly reduced. Typically, the eigensolution computational time for obtaining the train sample data using PFEM is only 1% of that using the traditional FEM. (c) 2005 Elsevier Ltd. All rights reserved.COMPOSITE STRUCTURES2007783402-409COMPOSITE STRUCTURES,2007,78(3):402-409Flexural strength distribution of 3D SiC/SiC compositehttp://ir.nwpu.edu.cn/AchivementDetails/Index/9859Wu, S.;Cheng, L.;Dong, N.,等2016/11/25 15:40:45Flexural strength of a four-step, three-dimensional (3D) braiding SiC/SiC composite was tested at room temperature. The strength distribution was studied based on Weibull distribution and Normal distribution as well as examined by the Kolmogorov test. The results indicated that the flexural failure behavior of the composite was rather brittle with a small displacement. And the statistical strength distribution of the 3D SiC/SiC composite was in agreement with two-parameter Weibull distribution of the Weibull modulus, m = 8.1545 and normal distribution. And the predicated mean flexural strength of the 3D SiC/SiC composite by the two-parameter Weibull distribution was consistent with the tested value.JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE2006156712-716JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE,2006,15(6):712-716A synthetic analysis on design of optimum control for an optimized intelligent structurehttp://ir.nwpu.edu.cn/AchivementDetails/Index/11616Yan, YJ;Yam, LH2016/11/25 15:42:03A hybrid optimization algorithm is developed to minimize the control energy and the structural weight under the constraints of the structural dynamic property requirements. A 72-bar space truss with two piezoelectric actuators is used to illustrate the complete process of this algorithm. It is shown that the control energy and the structural weight are clearly reduced using the proposed method. (C) 2002 Academic Press.JOURNAL OF SOUND AND VIBRATION20022494775-784JOURNAL OF SOUND AND VIBRATION,2002,249(4):775-784高超声速飞行器的模糊预测控制http://ir.nwpu.edu.cn/AchivementDetails/Index/19235王士星;孙富春;许斌2016/11/25 15:55:13为了简化已有的高超声速飞行器纵向通道反步法控制,提出了一种基于预测模型的模糊控制器.针对高度子系统,通过对原模型进行转换得到四步预测模型.控制器设计仅需一个模糊系统对不确定部分进行估计补偿,可避免虚拟控制量的不断求取.稳定性分析证明了系统跟踪误差是一致终值有界的.与反步法相比,该策略大大简化控制器的设计复杂度.仿真验证了算法的有效性.东南大学学报(自然科学版)201343z122-27东南大学学报(自然科学版),2013,43(z1):22-27基于混沌时间序列分析法的短时交通流预测研究http://ir.nwpu.edu.cn/AchivementDetails/Index/48183薛洁妮;史忠科2016/11/25 16:59:41交通流预测分析已成为智能交通的核心研究内容之一.依据混沌时间序列分析方法,建立了短时交通流的预测模型.在对实测的交通流数据进行相空间重构的基础上,综合考虑欧氏距离和均等系数,提出了最邻近点的两步优化选择方法,并采用了局部多项式拟合方法对所选取的最邻近点进行逼近以求得预测公式.本文将此方法运用于东莞东江大道流量预测,比较预测流量和实测流量,得出最大相对误差为0.445%,最小相对误差为0.038%,且单步预测时间仅为38.52秒.结果表明,该预测模型具有较高的精度,同时也能够满足实时性的要求.交通运输系统工程与信息20088568-72交通运输系统工程与信息,2008,8(5):68-72The Pre-twisted Thin-Walled Beam Element Stiffness Matrix Considering the Saint-Venant Warping Deformationhttp://ir.nwpu.edu.cn/AchivementDetails/Index/77667Chen, Changhong;Huang, Ying2016/11/25 18:08:28Based on the traditional mechanical model of thin-walled straight beam, the paper makes a systematic analysis and research on the pre-twisted thin-walled beam finite element numerical model. Firstly, based on the geometric deformation differential relationship, the paper deduces the pre-twisted thin-walled beam Saint-Venant warping strain. According to traditional thin-walled straight beam finite element mechanical model, the paper establishes its finite element stiffness matrix considering the Saint-Venant warping deformations. Finally, by calculating the pre-twisted elliptical section beam example, and contrasting three-dimensional solid finite element using ANSYS, the comparative analysis results show that pre-twisted thin-walled beam element stiffness matrix considering Saint-Venant warping deformation has good accuracy.APPLIED MECHANICS, FLUID AND SOLID MECHANICS2014871129-134APPLIED MECHANICS, FLUID AND SOLID MECHANICS,2014,871:129-134Speech feature extracting based on DSPhttp://ir.nwpu.edu.cn/AchivementDetails/Index/83560Niu, JT;Shi, ZK2016/11/25 18:12:40In this paper, for the voiced frame in the speech processing, the implementations of LPC prognosticate coefficient resolution by Levisohn-Durbin algorithm on the DSP based system was proposed, and also the implementation of L.R.Rabiner basic frequency estimation is discussed. At the end of this paper, several new methods of sound feature extraction only by voiced frame is also discussed.FIFTH INTERNATIONAL SYMPOSIUM ON INSTRUMENTATION AND CONTROL TECHNOLOGY20035253139-142FIFTH INTERNATIONAL SYMPOSIUM ON INSTRUMENTATION AND CONTROL TECHNOLOGY,2003,5253:139-142Influence of (RGO)/(ferrite) ratios and graphene reduction degree on microwave absorption properties of graphene compositeshttp://ir.nwpu.edu.cn/AchivementDetails/Index/221238Zong, Meng;Huang, Ying;Zhang, Na,等2016/11/25 19:30:34The reduced graphene oxide (RGO)/cobalt ferrite (CoFe2O4) composites with three different (RGO)/(CoFe2O4) ratios were synthesized by a one-pot hydrothermal route. To research the influence of graphene reduction degree on electromagnetic parameters of graphene composites, RGO/CoFe2O4-2 was treated further by reduction process with different reducing agents (N2H4/NaBH4). The crystalline structure, morphology, thermal stability, magnetic property of the synthesized samples were characterized by XRD, TEM, SEM, FT-IR, Raman, TG, VSM and XPS. The absorption properties of the RGO/CoFe2O4 composites were studied. The maximum R-L of RGO/COFe2O4-2 composite is -47.9 dB at 12.4 GHz with a thickness of 2.3 mm, and the absorption bandwidth with the R-L below -10 dB is up to 5.0 GHz (from 12.4 to 17.4 GHz) with a thickness of 2.0 mm. The results indicated that the RGO/CoFe2O4 composites have remarkably electromagnetic performance, which are attributed to effective complementarities between the dielectric loss and the magnetic loss. Additionally, the microwave absorption properties of the RGO/CoFe2O4 composites can be tuned easily by varying the (RGO)/(CoFe2O4) ratio, the reduction degree of graphene and layer thickness of the samples. (C) 2015 Elsevier B.V. All rights reserved.JOURNAL OF ALLOYS AND COMPOUNDS2015644491-501JOURNAL OF ALLOYS AND COMPOUNDS,2015,644:491-501A dynamic Bayesian networks model for structural time-dependent reliability with deteriorationhttp://ir.nwpu.edu.cn/AchivementDetails/Index/223175Wu, Z.Y.;Sun, H.B.;Liu, S.K.2016/11/25 19:32:46A dynamic Bayesian network (DBN) model is proposed for time-dependent reliability of structure with resistance deterioration. Gamma process is selected to model the deterioration process and loads are considered as random variables.The DBN of the structural time-dependent reliability is established by combining three models:deterioration model, reliability model, observation model, and is simplified with node elimination algorithm and discretization to allow exact inference. The framwork proposed is demonstrated by a one-bay frame with resistance deterioration. Comparison of the results obtained by DBN with Monte Carlo simulation approach, in terms of reliability index for 30 years shows the validity and accuracy of the DBN approach. Also exact inference of DBN such as filtering, prediction and smoothing with 10 years' evidence is presented in this paper. ? 2013 Taylor & Francis Group, London.11th International Conference on Structural Safety and Reliability, ICOSSAR 201320131191-119711th International Conference on Structural Safety and Reliability, ICOSSAR 2013,2013,1191-1197Crystallization and dielectric property of Si-B-C-N ceramics at different annealing temperatureshttp://ir.nwpu.edu.cn/AchivementDetails/Index/232530Ye, F.;Zhang, L.;Yin, X.,等2016/11/25 19:33:58Polymer derived Si-B-C-N ceramics were prepared from the liquid polyborosilazane. The TG-DSC analysis was carried out to determine the conditions of the crossing, curing and pyrolysis. The as-received Si-B-C-N ceramics were respectively annealed at 1200-1800 oC for 2 hours in a high-purity nitrogen atmosphere. The effects of annealing temperature on the surface morphology and phase composition of Si-B-C-N ceramics were discussed. With the increasing of temperature, the crystallization degree of ceramics increases gradually, the crystallization is more and more adequate, and the grains grow gradually. When temperature is up to 1800 oC, the crystallization of SiC has completed. Owing to the formation of SiC crystals and the increase of grain boundary, the permittivity and dielectric loss of Si-B-C-N ceramics gradually increase as the temperature increases. The reflection coefficient of Si-B-C-N ceramics was calculated in terms of the measured permittivity and permeability. It shows that the reflection coefficient gradually decreases as the annealing temperature increases, which demonstrates that the as-annealed ceramics possess the superior electromagnetic wave absorbing ability compared to as-received ceramics, and the higher annealing temperature is more conducive to the increase of waves-absorbing potential. KEY WORDS Si-B-C-N ceramics; heat treatment; crystallization; dielectric property; electromagnetic wave absorbing ability.27th Annual Technical Conference of the American Society for Composites 2012, Held Jointly with 15th Joint US-Japan Conference on Composite Materials and ASTM-D30 Meeting20121739-175027th Annual Technical Conference of the American Society for Composites 2012, Held Jointly with 15th Joint US-Japan Conference on Composite Materials and ASTM-D30 Meeting,2012,1739-1750Studies on ablation-resistant properties of inorganic nano-particles hybrid phenolic resinhttp://ir.nwpu.edu.cn/AchivementDetails/Index/238201Liu, Nai-Liang;Huang, Ying;Li, Chun-Hua,等2016/11/25 19:36:53Ablative thermal protection is a common thermal protection technology for recoverable spacecraft, which makes use of the decomposition, depolymerization, melting, evaporation, gasification or ionization of materials to transfer a large quantity of heat in order to ensure the safety of the internal device. The ablation-resistant properties of hybrid phenolic materials with 5 wt% SiC, SiO2 and Al2O3 inorganic nano-particles were studied in this paper. Glass transition temperature (Tg) of hybrid phenolic materials with SiC, SiO2 and Al2O3 inorganic nano-particles which studied by differential scanning calorimetry (DSC) increased by 6.31??C, 1.35??C and 4.93??C separately. This indicated that adding inorganic nano-particles hindered movement of molecular chain. Moreover the Tg values were also raised. Activation energies of thermal decomposition of different kinds of materials were calculated by Kissinger and Flynn-Wall-Ozawa method. It was found that after adding inorganic particles activation energy of thermal decomposition in the first stage decreased slightly, which made post-curing reaction easier. The degree of decreasing was: SiO2>Al2O3>SiC. While in the third stage activation energy of thermal decomposition increased to improve heat resistance of materials at high temperatures. The degree of increasing was: Al 2O3>SiC>SiO2. The average linear ablation rate of glass fiber reinforced pure phenolic, phenolic with SiC hybrid, phenolic with SiO2-hybrid and phenolic with Al2O 3-hybrid tested by oxygen-acetylene ablation were 0.210 mm/s, 0.178 mm/s, 0.194 mm/s and 0.166 mm/s separately. The morphologies of composite materials observed by scanning electron microscopy (SEM) after ablation showed that glass fiber were melted during ablation, which formed a compact insulating layer at the surface. The carbon layer ablated beside the decomposed area kept the porous structure caused by ablation, which reduced thermal conduction.61st International Astronautical Congress 2010, IAC 2010201064823-482861st International Astronautical Congress 2010, IAC 2010,2010,6:4823-4828Dynamically tunable Fano resonance in planar structures based on periodically asymmetric graphene nanodisk pairhttp://ir.nwpu.edu.cn/AchivementDetails/Index/275918Zhang, Zhengren;Su, Xiaopeng;Fan, Yuancheng,等2016/11/25 19:39:31We present a dynamically frequency tunable Fano resonance planar device composed of periodically asymmetric graphene nanodisk pair for the mid-infrared region. The two asymmetric graphene nanodisks can be directly excited by the light simultaneously and produce two kinds of reflected light with almost the same spectrum linewidth. By studying the local field distributions of our structure, we find that there are two kinds of modes for the two asymmetric graphene nanodisks, i.e., the symmetric mode and antisymmetric mode. Resonance coupling between the symmetric and antisymmetric modes generates the Fano resonance in our structure. This Fano resonance generation mechanism is different from it in traditional Fano resonance structure. In the traditional Fano resonance structure, the Fano resonance comes from the coupling effect between continuum and discrete structure. Moreover, we find that both of the Fano resonance amplitude and frequency of the structure can be dynamically controlled by varying the Fermi energy of graphene. Resonance transition in the structure is studied to reveal the physical mechanism behind it. (C) 2015 Elsevier B.V. All rights reservedPHYSICA B-CONDENSED MATTER20154737-10PHYSICA B-CONDENSED MATTER,2015,473:7-10Reconfigurable-focus flat lens based on gradient index metamaterialshttp://ir.nwpu.edu.cn/AchivementDetails/Index/304307Fu, Quanhong;Zhang, Fuli;Fan, Yuancheng2016/11/25 19:51:12We propose a reconfigurable-focus flat lens based on a gradient index metamaterial, which is composed of metal hole arrays incorporated with varactor diodes and is able to transform a plane wave into a cylindrical wave. The transmission phase of each metal hole array is modified by changing the width of the rectangular holes. With the gradient transmission phase along the lateral direction of a flat lens, a plane wave can be transformed into a cylindrical wave. By delicately designing the capacitance of varactor diodes, the focus length of a flat lens can be reconfigured by 1.3 cm. Furthermore, the focusing performance of a flat lens is still preserved for oblique incidence.JOURNAL OF OPTICS2015178JOURNAL OF OPTICS,2015,17(8)An extended signal control strategy for urban network traffic flowhttp://ir.nwpu.edu.cn/AchivementDetails/Index/447666Yan, Fei;Tian, Fuli;Shi, Zhongke2016/11/25 20:29:24Traffic flow patterns are in general repeated on a daily or weekly basis. To improve the traffic conditions by using the inherent repeatability of traffic flow, a novel signal control strategy for urban networks was developed via iterative learning control (ILC) approach. Rigorous analysis shows that the proposed learning control method can guarantee the asymptotic convergence. The impacts of the ILC-based signal control strategy on the macroscopic fundamental diagram (MFD) were analyzed by simulations on a test road network. The results show that the proposed ILC strategy can evenly distribute the accumulation in the network and improve the network mobility. (C) 2015 Elsevier B.V. All rights reserved.PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS2016445117-127PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS,2016,445:117-127Electrically tunable Fano-type resonance of an asymmetric metal wire pairhttp://ir.nwpu.edu.cn/AchivementDetails/Index/559810Fu, Quanhong;Zhang, Fuli;Fan, Yuancheng,等2017/5/15 9:33:11We theoretically and experimentally investigate the electrically tunable Fano-type resonance of asymmetric metal wire pair loaded with varactor diodes. It is illustrated that Fano-type transmission spectrum with high quality factor Q appears as a result of interference between the dipole and quadrupole modes. The ohmic loss of series resistance in varactor diode makes major contribution to absorption. At the Fano-type resonance frequency, both the two metal wires exhibit the strongest electric resonance simultaneously, and the Fano-type resonance manifests a large group delay. As the bias voltage ranges from 0 V to 8 V, the Fano-type resonance frequency exhibits a prominent blueshift of 0.16 GHz and the transmission experiences a modulation with a modulation depth of 97%. (C) 2016 Optical Society of AmericaOPTICS EXPRESS201624111708-1715OPTICS EXPRESS,2016,24(11):1708-1715Minimal-learning-parameter technique based adaptive neural control of hypersonic flight dynamics without back-steppinghttp://ir.nwpu.edu.cn/AchivementDetails/Index/813126Xu, Bin;Fan, Yonghua;Zhang, Shangmin2016/12/5 18:25:08This paper investigates one robust adaptive controller for hypersonic flight dynamics. The altitude tracking is transformed into the control problem of the attitude subsystem, which is composed of flight path angle, pitch angle and pitch rate. Different from previous design using back-stepping related technique, this paper analyzed the tracking control without back-stepping where the controller is synthesized with high gain observer and minimal-learning-parameter technique. The highlight is that the design procedure is greatly simplified and the computation burden of parameter updating is reduced. It is proved that the filtered tracking error is guaranteed in the semiglobal sense. Simulation results are presented to demonstrate the effectiveness of the design. (C) 2015 Elsevier B.V. All rights reserved.NEUROCOMPUTING2015164201-209NEUROCOMPUTING,2015,164:201-209Action recognition based on semantic feature description and cross classificationhttp://ir.nwpu.edu.cn/AchivementDetails/Index/818870Zhao, Yang;Wang, Qi;Yuan, Yuan2016/12/5 19:38:18Action recognition is a challenging topic in computer vision. In this work, we present a novel method for action recognition which is based on two claimed contributions: semantic feature description and cross classification. The designed descriptor is combined by several local 3D-SIFT and is informative and distinctive, reflecting the spatiooral clues of the video. The cross classification effectively combines the feature localization and action categorization together. The proposed method is justified on a popular dateset named UCF50 and the experimental results demonstrate that our method outperforms the state-of-the-art competitors. ? 2014 IEEE.2nd IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 20142014626-6302nd IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014,2014,626-630Synthesis of functionalized graphene oxide nanoflakes using silane coupling agentshttp://ir.nwpu.edu.cn/AchivementDetails/Index/920368Ding, Juan;Huang, Ying;Han, Tiaozheng,等2016/12/7 10:33:47Carbon-based nanomaterials have captured significant interest in academics for decades. Recently, graphene has been found to be a promising nanomaterial. In this study, novel functionalized graphene oxide nanoflakes (FGONs) were successfully synthesized using silane coupling agents via a chemical approach and used as a reinforcement in cyanate ester (CE)/bismaleimide (BMI) copolymers. The curing mechanism and thermal properties of the FGONs/CE/BMI nanocomposites were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry. The results show that the addition of FGONs not only catalyzed the entire curing process but also increased the thermal stability of the nanocomposites. The flexural and impact strengths reached optimum values of 110 MPa and 10.98 kJ m-2with a load of 1.0 wt% FGONs, respectively. Moreover, the glass transition temperature and dielectric properties of the nanocomposites were lower than those of the CE/BMI copolymer. ? 2015 The Author(s).High Performance Polymers2016282147-155High Performance Polymers,2016,28(2):147-155Simulation of combined conductive, convective and radiative heat transfer in moving irregular porous fins by spectral element methodhttp://ir.nwpu.edu.cn/AchivementDetails/Index/991961Ma, Jing, Sun, Yasong, Li, Benwen,2017/8/18 8:23:32A spectral element method (SEM) is developed to solve coupled conductive, convective and radiative heat transfer in moving porous fins of trapezoidal, convex parabolic and concave parabolic profiles. In these irregular porous fins, non-uniform heat generation, heat transfer coefficient and surface emissivity vary with temperature. In the SEM model, the solution domain is decomposed into non-overlapping elements by mesh tools of finite element method, and Chebyshev polynomials are used to establish basis functions on each element. A case of nonlinear heat transfer in the irregular porous fin is taken as an example to verify the performance of SEM. Compared with available data in the literature, SEM can provide a good accuracy. The h and p convergence characteristics of SEM are also studied. The p convergence rate is faster than the h convergence rate and approximately follows an exponential law. In addition, a volume adjusted fin efficiency is developed to evaluate the thermal performance of irregular porous fin. The effects of porous materials, irregular profiles and other thermo-physical parameters, such as Peclet number, surface emissivity coefficient, power index of heat transfer coefficient, convective conductive parameter, radiative-conductive parameter, non-dimensional heat generation at ambient temperature, heat generation parameters, porosity and non-dimensional ambient temperature on non dimensional temperature and fin efficiency are also studied. (C) 2017 Elsevier Masson SAS. All rights reserved.INTERNATIONAL JOURNAL OF THERMAL SCIENCES2017118475-487INTERNATIONAL JOURNAL OF THERMAL SCIENCES,2017,118:475-487Global hashing system for fast image searchhttp://ir.nwpu.edu.cn/AchivementDetails/Index/995194Dayong Tian, Dacheng Tao,2017/11/14 15:37:30IEEE Transactions on Image Processing201726179-89IEEE Transactions on Image Processing,2017,26(1):79-89Coupled learning for facial deblurhttp://ir.nwpu.edu.cn/AchivementDetails/Index/995195Dayong Tian, Dacheng Tao,2017/11/14 15:40:32IEEE Transactions on Image Processing2016252961-972IEEE Transactions on Image Processing,2016,25(2):961-972Generalized correlation for shape alignmenthttp://ir.nwpu.edu.cn/AchivementDetails/Index/995196Dayong Tian, Maoguo Gong, Linzhi Su,2017/11/14 15:43:53Information Science201636340-51Information Science,2016,363:40-51Viral and cellular N-6-methyladenosine and N-6,2 '-O-dimethyladenosine epitranscriptomes in the KSHV life cyclehttp://ir.nwpu.edu.cn/AchivementDetails/Index/995807Tan, Brandon, Liu, Hui, Zhang, Songyao, et al. 2018/2/14 15:55:35N-6-methyladenosine (m(6)A) and N-6,2'-O-dimethyladenosine (m(6)Am) modifications (m(6)A/m) of messenger RNA mediate diverse cellular functions. Oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases that are essential for the development of KSHV-associated cancers. To date, the role of m(6)A/m in KSHV replication and tumorigenesis is unclear. Here, we provide mechanistic insights by examining the viral and cellular m(6)A/m epitranscriptomes during KSHV latent and lytic infection. KSHV transcripts contain abundant m(6)A/m modifications during latent and lytic replication, and these modifications are highly conserved among different cell types and infection systems. Knockdown of YTHDF2 enhanced lytic replication by impeding KSHV RNA degradation. YTHDF2 binds to viral transcripts and differentially mediates their stability. KSHV latent infection induces 5' untranslated region (UTR) hypomethylation and 3'UTR hypermethylation of the cellular epitranscriptome, regulating oncogenic and epithelial-mesenchymal transition pathways. KSHV lytic replication induces dynamic reprogramming of epitranscriptome, regulating pathways that control lytic replication. These results reveal a critical role of m(6)A/m modifications in KSHV lifecycle and provide rich resources for future investigations.NATURE MICROBIOLOGY201831108-120NATURE MICROBIOLOGY,2018,3(1):108-120轴对称塞式喷管电磁散射特性数值模拟http://ir.nwpu.edu.cn/AchivementDetails/Index/995811陈玲玲, 杨青真, 陈立海, et al. 2017/11/20 8:45:48为研究塞锥存在对喷管雷达隐身特性的影响,以涡扇发动机轴对称喷管为基础,设计了加有不同锥度塞锥的塞式喷管;运用自主开发的基于物理光学迭代(IPO)和等效边缘电磁流(EEC)方法的程序对各型塞式喷管的雷达散射特性进行了数值计算并与原轴对称喷管特性进行对比分析。结果表明:塞式喷管能够有效降低喷管雷达散射截面(RCS);但0°仰俯角附近会有局部升高,在水平极化和垂直极化方式下RCS值分别比原喷管最大增大8.14%,11.77%;存在最优锥度,在水平和垂直极化方式下都能够最大程度减小喷管总场RCS均值,使得其比原喷管分别减缩13.2%,15.2%。推进技术2018011-6推进技术,2018,01,1-6弯掠优化对高负荷跨声速串列转子的影响分析http://ir.nwpu.edu.cn/AchivementDetails/Index/995815宋召运, 刘波, 张鹏, et al. 2017/11/20 8:45:54为了研究三维弯掠优化对串列转子性能的影响,设计了一套基于NURBS参数化方法和Kriging代理模型的串列转子三维弯掠优化系统。以一高负荷跨声速串列转子为研究对象,分别研究了掠形优化、弯形优化和复合弯掠优化对串列转子性能的影响。结果表明:三维弯掠优化可以改善串列转子的性能,与原型串列转子相比,前掠转子、正弯转子和复合弯掠转子在近设计点的效率分别提高了1%,1.03%,1.47%,正弯转子的稳定裕度增加了23%,但前掠转子和复合弯掠转子稳定裕度有少许下降。在高负荷跨声速串列转子的弯掠优化造型中,前掠造型能改善串列转子叶中和叶尖的性能,叶根性能有所下降,正弯造型能改善串列转子大部分叶展的性能,弯掠优化造型提升高负荷跨声速串列转子效率的原因是弯掠优化降低了转子通道正激波的波前马赫数,而激波位置基本不变。推进技术2018011-10推进技术,2018,01,1-10进口畸变下缝式机匣处理改善轴流压气机性能的研究http://ir.nwpu.edu.cn/AchivementDetails/Index/995817张皓光, 谭锋, 安康, et al. 2017/11/20 8:46:00为了研究进口畸变下缝式机匣处理改善轴流压气机性能的机理,以亚声速单级轴流压气机的孤立转子为研究对象,在53.4%设计转速下,采用10通道非定常的数值模拟方法,开展进口畸变下轴向倾斜缝机匣处理改善轴流压气机性能的机理研究。采取在进口径向延伸段中部沿周向设置栏杆的方式产生畸变。与进口均匀实体壁机匣相比,进口畸变实体壁机匣的失速裕度改进量和峰值效率改进量分别为-5.88%和-1.44%,而进口畸变带机匣处理的失速裕度改进量和峰值效率改进量分别为24.37%和-1.09%。进口均匀实体壁机匣时,压气机的失速类型为典型的突尖型失速,即由叶顶间隙泄漏流引起的堵塞所造成。进口畸变引发叶顶处吸力面的气流分离,且气流分离沿周向呈非轴对称分布,进口畸变后叶顶通道内的低速区在很大程度上还是由叶顶间隙泄漏流所造成,只不过相比于进口均匀,叶顶处吸力面的气流分离提前发生,并且反过来又加剧叶顶间隙泄漏流的负面影响,即进口畸变后压气机失速的主要诱因没有发生本质的变化。机匣处理上、下游的喷射、抽吸过程分别对叶顶通道上游、中部的低速区气流起到激励、吹除作用,其有效地抑制了由叶顶间隙泄漏流所造成的叶顶前缘溢流和叶顶通道内压力面附近的回流,进而提高推进技术2018011-13推进技术,2018,01,1-13FLADE变循环发动机模态转换过程特性分析http://ir.nwpu.edu.cn/AchivementDetails/Index/995818张晓博, 王占学, 周红,2017/11/20 8:46:05为对带FLADE(Fan on Blade)的变循环发动机总体性能进行评估,发展了FLADE部件计算方法以及带FLADE的双外涵变循环发动机稳态性能计算模型,加入反映转子惯性效应和部件容积效应的动力学方程,建立了变循环发动机过渡态性能计算模型。分析了FLADE变循环发动机在双外涵与单外涵模式之间的模态转换过渡态特性,重点研究了几何参数调节及其不同组合形式对FLADE变循环发动机模态转换过程的影响。结果表明,带FLADE的双外涵变循环发动机的模态转换过程只与FLADE导叶角度和FLADE喷管面积有关,且两者应同时放大或关小;FLADE的开/关对风扇外涵气流及核心机的影响较小。推进技术2018011-9推进技术,2018,01,1-9从财务资本导向到智力资本导向:公司治理范式的演进研究http://ir.nwpu.edu.cn/AchivementDetails/Index/1028852张雪,2018/2/25 21:05:32本文运用科学哲学中的Kuhn范式理论对公司治理的历史演进进行了梳理和研究,提出了公司治理正在从财务资本导向范式向智力资本导向范式演进的命题。第一次产业革命后,工业经济在相当长的发展时期内,财务资本作为最稀缺的资源在企业生产和并购活动中扮演关键角色。资本雇佣劳动信念逐渐形成并不断强化,在此基础上形成了财务资本掌握控制权、以股东利益最大化为目标、以同股同权为原则的财务资本导向公司治理范式。知识经济时代到来后,公司治理实践中的新现象使财务资本导向公司治理范式的基本信念、目标和原则发生了动摇和松弛。中国工业经济20181156-173中国工业经济,2018,1,156-173Application of a Cohesive Zone Model for Simulating Fatigue Crack Growth from Moderate to High Delta K Levels of Inconel 718http://ir.nwpu.edu.cn/AchivementDetails/Index/1030127Li, Huan, Li, Jinshan, Yuan, Huang,2018/3/17 13:55:43A cyclic cohesive zone model is applied to characterize the fatigue crack growth behavior of a IN718 superalloy which is frequently used in aerospace components. In order to improve the limitation of fracture mechanics-based models, besides the predictions of the moderate fatigue crack growth rates at the Paris' regime and the high fatigue crack growth rates at the high stress intensity factor Delta K levels, the present work is also aimed at simulating the material damage uniformly and examining the influence of the cohesive model parameters on fatigue crack growth systematically. The gradual loss of the stress-bearing ability of the material is considered through the degradation of a novel cohesive envelope. The experimental data of cracked specimens are used to validate the simulation result. Based on the reasonable estimation for the model parameters, the fatigue crack growth from moderate to high Delta K levels can be reproduced under the small-scale yielding condition, which is in fair agreement with the experimental results.INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING20182018INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING,2018,2018