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Feasibility study of thermo-compensated resistance brazing welding of C/C composites and T2 copper with AgCuTi filler metal

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Chinese Journal of Aeronautics 2023年第5期36卷 534-548页

作者： Jiang YU Xinglin MIAO Hongtao ZHANG bo WANG Changming qu Peng HE State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Institute for Shipwelding Technology Shandong Institute of Shipbuilding TechnologyWeihai 264209China

The dissimilar materials joining of C/C composites to T2 copper were performed successfully by thermo-compensated Resistance Brazing Welding(RBW)with AgCuTi filler *** interfacial microstructure,phase composition,and shear strength of the resistance brazed joints were investigated by the relevant analysis *** results indicated that the order affecting the shear strength of the C/C-Cu joint was welding current,welding pressure,and welding time in *** shear strength of backward thermo-compensated RBW was higher than that of forward thermo-compensated RBW due to the Peltier *** maximum shear strength of the C/C-Cu joint was 11.56 MPa in the optimized welding parameter with welding current of 8.0 kA,welding time of 60 ms,and welding pressure of 0.10 MPa by backward thermo-compensated *** interface structure at the resistance brazed joint with this welding parameter was C/C composites/TiC/Cu(s.s)/T2 *** TiC phase was verified at the interface of the brazed joint by Scanning Electron Microscope(SEM),Energy-Dispersive X-ray Spectrometer(EDS),and X-ray Diffraction(XRD).Considerable fractures occurred in the C/C composites and partial fracture occurred at the interfacial reaction layer.

关键词： AgCuTi C/C composites Copper Resistance Brazing welding Shear strength

Compact wideband FSS-absorber-based low-RCS reflectarray antenna

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Chinese Journal of Aeronautics 2023年第6期36卷 332-339页

作者： Jianing YANG Yanting ZHANG ming-Chun TANG Zhehao ZHANG Meijun qu School of Microelectronics and Communication Engineering Chongqing UniversityChongqing 400044China State Key Laboratory of Media Convergence and Communication Communication University of ChinaBejing 100024 China

This paper presents a method to realize compact broadband low-RCS ReflectArray(RA)antenna based on a Frequency Selective Surface(FSS)absorber and a reflective *** an FSS absorber consists of a resistance-loaded lossy layer and an FSS layer,which is utilized to reach an absorption-transmission *** bottom reflective metasurface works as a phase array,reshaping the quasi-sphere wave from the feeding antenna into the quasi-plane *** a demonstration,the low-RCS RA antenna is simulated,fabricated,and *** simulated and measured results show that the developed low-RCS RA antenna has an aperture efficiency of 42.7%and a gain of 25.4 dBi in the X *** the meantime,it simultaneously reaches the 10 dB RCS reduction for the orthogonal polarizations at the S and C bands,corresponding to a fractal bandwidth of 120%.Specifically,the adopted patch-feeding antenna makes the RA antenna more compact than the horn-feed conventional ***,the proposed RA antenna uses a few layers of substrates,making it lower in cost and easier for *** proposed design may have potential application in integrated stealth communication systems.

关键词： Absorption Broadband RCS reduction Compactness Reflectarray antenna Stealth

Noise-Induced Voltage Collapse in Power Systems

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Chinese Physics Letters 2012年第3期29卷 44-47页

作者： WEI Du-qu LUO Xiao-Shu ZHANG bo College of Electronic Engineering Guangxi Normal UniversityGuilin 541004 College of Electric Power South China University of TechnologyGuangzhou 510640

We investigate numerically the influences of Gaussian white noise on the dynamical behaviors of power *** studied model is a three-bus system at some specific parameters,and it demonstrates a stable regime that is far from *** is found that with the increasing noise intensityσ,power systems become unstable and fall into oscillations;asσis further increased,noise-induced voltage collapse in power systems takes *** results confirm that the presence of noise has a detrimental effect on power system ***,the possible mechanism behind the action of noise is addressed based on a dynamical approach where the bifurcation of the system is *** results may provide useful information for avoiding instability problems in power systems.

关键词： system systems unstable

Hardware-in-loop adaptive neural control for a tiltable V-tail morphing aircraft

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Defence Technology（防务技术） 2023年第4期22卷 197-211页

作者： Fu-xiang Qiao Jing-ping Shi Xiao-bo qu Yong-xi Lyu School of Automation Northwestern Polytechnical UniversityXi'an710129China Shaanxi Province Key Laboratory of Flight Control and Simulation Technology Xi'an710129China

This paper proposes an adaptive neural control(ANC)method for the coupled nonlinear model of a novel type of embedded surface morphing aircraft which has a tiltable V-tail.A nonlinear model with sixdegrees-of-freedom is *** first-order sliding mode differentiator(FSMD)is applied to the control scheme to avoid the problem of“differential explosion”.Radial basis function neural networks are introduced to estimate the uncertainty and external disturbance of the model,and an ANC controller is proposed based on this design *** stability of the proposed ANC controller is proved using Lyapunov theory,and the tracking error of the closed-loop system is semi-globally uniformly *** effectiveness and robustness of the proposed method are verified by numerical simulations and hardware-in-the-loop(HIL)simulations.

关键词： Morphing aircraft Back-stepping control Adaptive control Neural networks Radial basis function

Fuzzy Q-learning in continuous state and action space

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The Journal of China Universities of Posts and Telecommunications 2010年第4期17卷 100-109页

作者： XU ming-liang XU Wen-bo Department of Electronic Information Engineering Wuxi City College of Vocational Technology Wuxi 214063 China School of Information Technology Jiangnan University Wuxi 214122 China

An adaptive fuzzy Q-leaming （AFQL） based on fuzzy inference systems （FIS） is proposed. The FIS realized by a normalized radial basis function （NRBF） neural network is used to approach Q-value function, whose input is composed of state and action. The rules of FIS are created incrementally according to the novelty of each element of the pair of state-action. Moreover the premise part and consequent part of the FIS are updated using extended Kalman filter （EKF）. The action that impacts on environment is the one with maximum output of FIS in the current state and generated through optimization method. Simulation results in the wall-following task of mobile robots and the inverted pendulum balancing problem demonstrate that the superiority and applicability of the proposed AFQL method.

关键词： Q-learning FIS continuous adaptation

Unsaturated Creep Behaviors of Weak Intercalated Soils in Soft Rock of Badong Formation

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Journal of Mountain Science 2015年第6期12卷 1460-1470页

作者： ZHU Yan-bo YU Hong-ming College of Geology Engineering and Geomatics Chang'an University Faculty of Engineering China University of Geosciences

The cutting slopes in soft rock of redbed appeared in Yichang-Badong highway often suffer from the instability along weak intercalations, so the creep behaviors of weak intercalated soils are crucially important for the stability of cutting slopes. Because the deformation of weak intercalated soils is significantly affected by water content due to the strong water sensitivity, it is necessary to study the influence of matric suction on the creep behaviors of weak intercalated soils. In order to find out the unsaturated creep characters of weak intercalated soils, a GDS unsaturated triaxial apparatus was used. Then the triaxial creep experiments on weak intercalated soil samples under varying matric suction were conducted to obtain the unsaturated creep curves. The results show that the weak intercalated soils have obvious creep behaviors, and the creep strain is in nonlinear relationship with stress and time. When the matric suction is constant, a larger deviator stress will lead to a larger creep strain; When the deviator stress is constant, a smaller matric suction will lead to a larger creep strain. Based on the Mesri creep model, an improved creep model for weak intercalated soils under varying matric suction was established, in which the relationship of stress-strain was expressed with a hyperbolic function, and the relationship of strain-time was expressed with power functions in stages. Then an unsaturated creep model including stress-matric suction-strain-time for weak intercalated soils was established based on the power function relationship between matric suction and Ed(a parameter of the improved creep model). The comparison of the calculated values of creep model and the experimental values shows that the creep behaviors of weak intercalated soils can be predicted by the unsaturated creep model by and large.

关键词： Badong formation Weak intercalated soils Unsaturated creep behaviors Soil triaxial apparatus Creep model

Structural and Optical Characteristics of InGaN／GaN Multi-quantum Wells Grown on α-and c-Plane Sapphire Substrates

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Chinese Physics Letters 2004年第7期21卷 1323-1326页

作者： YUHong-bo CHENHong LIDong-Sheng ZHOUJun-ming StateKeyLaboratoryforSurfacePhysics InstituteofPhysicsChineseAcademyofSciencesPOBox603Beijing100080

We investigate the structural and optical properties of InGaN-based multi-quantum wells grown on a–c plane sapphire substrates by atomic force microscopy, high-resolution x-ray diffraction and temperature-dependent photoluminescence measurements. The multi-quantum wells grown on a-plane sapphire substrate show stronger exciton localization effect compared with that grown on the c-plane substrate, although the threading dislocation densities in the two samples are almost the same. We attribute the results to the different in-plane strain of quantum well grown on different substrate orientations at the same growth temperature. Since the exciton localization effect plays a key role to obtain high efficiency InGaN-based optoelectronics devices, the presented result should be emphasized.

关键词： Strain

Development of ELISA and immunochromatographic assay for ofloxacin

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Chinese Chemical Letters 2007年第9期18卷 1107-1110页

作者： Wu Yong Sun Wen Ying Liu Ling bo qu Department of Pharmacy China Pharmaceutical UniversityNanjing 210009China Department of Chemistry Zhengzhou UniversityZhengzhou 450052China

Two rapid, sensitive and reliable immunoassay methods, namely competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) and colloidal gold-based immunochromatographic assay (CGIA), were developed to detect ofloxacin (OFL). The linear range of the CI-ELISA was from 0.5 to 128 ng/mL with a limit of detection (LOD) of 0.35 ng/mL. Good recoveries were obtained in analyzing simulated swine urine samples. The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min, and test results were read visually without any instrument.

关键词： Ofloxacin (OFL) Polyclonal antibody (pAb) Competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) Colloidal gold-based immunochromatographic assay (CGIA)

Signifying quantum uncertainty relations by optimal observable sets and the tightest uncertainty constants

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 43-50页

作者： Xiao-Bin Liang bo Li Shao-ming Fei School of Mathematics and Computer Science Shangrao Normal UniversityShangrao 334001China quantum Information Research Center Shangrao Normal UniversityShangrao 334001China School of Mathematical Sciences Capital Normal UniversityBeijing 100048China

quantum uncertainty relations constrain the precision of measurements across multiple non-commuting quantum mechanical ***,we introduce the concept of optimal observable sets and define the tightest uncertainty constants to accurately describe these measurement *** any quantum state,we establish optimal sets of three observables for both product and summation forms of uncertainty relations,and analytically derive the corresponding tightest uncertainty *** demonstrate that the optimality of these sets remains consistent regardless of the uncertainty relation ***,the existence of the tightest constants excludes the validity of standard real quantum mechanics,underscoring the essential role of complex numbers in this ***,our findings resolve the conjecture posed in[***.118,180402(2017)],offering novel insights and potential applications in understanding preparation uncertainties.

关键词： uncertainty relation the tightest uncertainty constants optimal observable sets