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Nanoindentation response analysis of TiN-Cu coating deposited by magnetron sputtering

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Progress in Natural Science:Materials International 2018年第1期28卷 40-44页

作者： Fuxing Ye xu sun School of Materials Science & Engineering Tianjin University Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University Tianjin Key Laboratory of Advanced Joining Technology Tianjin University

To investigate the change of the mechanical properties of soft metals doped PVD(Physical Vapor Deposition)coatings after the migration of soft metal to the surface, TiN-Cu coating was deposited on Si(100) by magnetron sputtering. The microstructure and mechanical properties at room temperature and after vacuum heat treatment at 300 ℃ were investigated. The results showed that the grains were clustered and the microstructure was porous for TiN-Cu coating at room temperature, while many micro-and nano-sized Cu particles were observed on the surface after vacuum heat treatment at 300 ℃. The elastic properties of the TiN-Cu coating after vacuum heat treatment at 300℃ degraded compared with that at room temperature. The hardness and elasticity modulus of TiN-Cu coating kept constant(3.7 GPa and 125.0 GPa, respectively) with the increase of nano-indentation depth, while the hardness and elasticity modulus of TiN-Cu coating after vacuum heat treatment at 300 ℃ increased gradually.

关键词： TiN-Cu coating Vacuum heat treatment Mechanical properties Nano-indentation depth

Resolution Enhancement in Ultrasonic TOFD Imaging by Combining Sparse Deconvolution and Synthetic Aperture Focusing Technique(Sparse-SAFT)

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 141-149页

作者： xu sun Li Lin Shijie Jin School of Materials Science and Engineering Dalian University of TechnologyDalianChina

The shallow subsurface defects are difficult to be identified and quantified by ultrasonic time-of-flight diffraction(TOFD)due to the low resolution induced by pulse width and beam *** this paper,Sparse-SAFT is proposed to improve the time resolution and lateral resolution in TOFD imaging by combining sparse deconvolution and synthetic aperture focusing technique(SAFT).The mathematical model in the frequency domain is established based on the l1 and l2 norm constraints,and the optimization problem is solved for enhancing time *** this basis,SAFT is employed to improve lateral resolution by delay-and-sum *** simulated and experimental results indicate that the lateral wave and tip-diffracted waves can be decoupled with *** shallow subsurface defects with a height of 3.0 mm at the depth of 3.0 mm were detected quantitatively,and the relative measurement errors of flaw heights and depths were no more than 10.3%.Compared to conventional SAFT,the time resolution and lateral resolution are enhanced by 72.5 and 56%with Sparse-SAFT,***,the proposed method is also suitable for improving resolution to detect the defects beyond dead zone.

关键词： Time resolution Lateral resolution Time-of-flight diffraction(TOFD) Sparse deconvolution Synthetic aperture focusing technique(SAFT) Sparse-SAFT

Dimensional effects of organic anion templates in modulating the assembly of water clusters in cucurbit[6]uril supramolecular systems

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Chinese Chemical Letters 2016年第3期27卷 417-422页

作者： Bo Li xu-Zhuo sun College of Chemistry and Chemical Engineering Henan University of Technology

Two new supramolecular architectures {（HC2O4）2^2- [C6H（18）N2^2＋ C（36）H（36）N（24）O（12）]} 12H2O（1） and{（C6H5SO3）22 [C6H（18）N22＋ C（36）H（36）N（24）O（12）]} 12H2O（2） were synthesized and characterized by singlecrystal X-ray diffraction, thermogravimetric analysis and X-ray powder diffraction. Compound 1contains infinite two dimensional（2D） L18（8）14（8）8（4） type anion–water aggregates [（HC2O4）4（H2O）（22）]^4- and results in the construction of sandwich-like three dimensional（3D） networks. In compound 2, honeycomb-like three dimensional（3D） networks are fabricated by one dimensional（1D）＂W＂-like T5（0）A2 type anion–water clusters [（C6H5SO3）（H2O）6]^-. These results indicate that anionic groups play a crucial role in modulating the structures of water clusters with their spatial structure and binding sites. In these two structures, the majority of interactions are O...H and H...H interactions on the Hirshfeld surface, which means that hydrogen bonding and hydrophobic interactions are the dominate drive forces in forming these supramolecular systems.

关键词： Cucurbituril Supramolecular Water clusters Anion templates Pseudorotaxane

NF_3 decomposition over Al_2O_3 reagents without water

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Journal of Natural Gas Chemistry 2011年第4期20卷 418-422页

作者： Xiufeng xu Liang sun Yanan Wang School of Chemistry and Biology Yantai University Yantai 264005 Shandong China

Several Al2O3 samples were prepared by a precipitation method coupled with ultrasonic treatment,and NF3 decomposition without water over Al2O3 reagents is carried *** effect of preparation parameters of Al2O3 reagents,such as precipitating agents,structure directing agents,and calcining temperatures on their reactivity for NF3 decomposition has been *** results show that NF3 can be decomposed completely at 400-C,and full conversion of NF3 maintains 580 min over the best Al2O3 reagent,calcined at 600-C which was prepared using both PEG-2000 and Tween-60 as structure directing agents,ammonia as a precipitating agent.

关键词： NF3 decomposition without water Al2O3 preparation parameters reactivity

Design and comparison of minimal symmetric model-subset for maneuvering target tracking

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Journal of Systems Engineering and Electronics 2010年第2期21卷 268-272页

作者： Fuming sun xu E Hongyu Ma School of Electronic and Informational Engineering Liaoning University of Technology Jinzhou 121001 E R. China

Model-set is utilized in state estimation for maneuver- ing target tracking. Two minimal symmetric model-subsets are designed and investigated by moment matching method, which include hypersphere-symmetric model-subset and axis-symmetric model-subset, if system mode is a random variable and obeys certain probability distribution. They can be used as the fun- damental model-subset for multiple models estimation with fixed structure, variable structure and moving bank. The model-groups constructed by above designed subsets are given, which give the practical guidance for use of model-set in multiple models ap- proach with a variable structure. Simulation results show that the performances of two minimal model-set significantly outperform the corresponding model-sets with fixed spacing.

关键词： adaptive estimation multiple models target tracking variable structure.

EV Response Capability Assessment Considering User Travel Demand and Cyber System Reliability

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Engineering 2022年第8期8卷 186-195页

作者： Yanli Liu Ke Liu xu sun School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China

With the increasing penetration rate of electric vehicles(EVs),EV demand response holds great significance for promoting the optimal and secure operation of the power *** paper proposes an EV response capability assessment method that considers EV users’travel demands and the reliability of the cyber systems integrated into both the power grid and the transportation network.A novel framework for an integrated cyber-power-transportation system is proposed for the first time,and a reliability model for the cyber system is provided.A method is further proposed to calculate the state of an EV when it is plugged in,considering the reliability of traffic guidance information and the reliability of the release of such *** degree of relaxation in the EV charging demand is proposed to reflect the user’s travel demand,based on which the EV response capability can be *** test results on a cyber-power-transportation system containing RBTS BUS6 and the Beijing transportation network are conducted to show the efficiency of the proposed *** impact of cyber reliability on the EV trip and response capability is analyzed.

关键词： Cyber system Demand response Electric vehicle

A Spectrally Accurate Boundary Integral Method for Interfacial Velocities in Two-Dimensional Stokes Flow

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Communications in Computational Physics 2010年第9期8卷 933-946页

作者： xu sun Xiaofan Li Department of Applied Mathematics Illinois Institute of TechnologyChicagoIL 60616USA.

We present a new numerical method for solving two-dimensional Stokes flow with deformable interfaces such as dynamics of suspended drops or *** method is based on a boundary integral formulation for the interfacial velocity and is spectrally accurate in *** analyze the singular behavior of the integrals(single-layer and double-layer integrals)appearing in the *** interfaces are formulated in the tangent angle and arc-length coordinates and,to reduce the stiffness of the evolution equation,the marker points are evenly distributed in arc-length by choosing a proper tangential velocity along the *** of Stokes flow with bubbles are provided to demonstrate the accuracy and effectiveness of the numerical method.

关键词： Boundary integral method Stokes flow two-phase flow weakly singular integral spectral accuracy

Robust and Discriminative Feature Learning via Mutual Information Maximization for Object Detection in Aerial Images

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Computers, Materials & Continua 2024年第9期80卷 4149-4171页

作者： xu sun Yinhui Yu Qing Cheng School of Communication Engineering Jilin UniversityChangchun130012China

Object detection in unmanned aerial vehicle(UAV)aerial images has become increasingly important in military and civil *** object detection models are not robust enough against interclass similarity and intraclass variability of small objects,and UAV-specific nuisances such as uncontrolledweather *** previous approaches focusing on high-level semantic information,we report the importance of underlying features to improve detection accuracy and robustness fromthe information-theoretic ***,we propose a robust and discriminative feature learning approach through mutual information maximization(RD-MIM),which can be integrated into numerous object detection methods for aerial ***,we present the rank sample mining method to reduce underlying feature differences between the natural image domain and the aerial image ***,we design a momentum contrast learning strategy to make object features similar to the same category and dissimilar to different ***,we construct a transformer-based global attention mechanism to boost object location semantics by leveraging the high interrelation of different receptive *** conduct extensive experiments on the VisDrone and Unmanned Aerial Vehicle Benchmark Object Detection and Tracking(UAVDT)datasets to prove the effectiveness of the proposed *** experimental results show that our approach brings considerable robustness gains to basic detectors and advanced detection methods,achieving relative growth rates of 51.0%and 39.4%in corruption robustness,*** code is available at https://***/cq100/RD-MIM(accessed on 2 August 2024).

关键词： Aerial images object detection mutual information contrast learning attention mechanism

Integrated Equivalent Model of Permanent Magnet Synchronous Generator Based Wind Turbine for Large-scale Offshore Wind Farm Simulation

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Journal of Modern Power Systems and Clean Energy 2023年第5期11卷 1415-1426页

作者： Ming Zou Yan Wang Chengyong Zhao Jianzhong xu Xiaojiang Guo xu sun State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University(NCEPU)BeijingChina China Huaneng Group Clean Energy Technology Research Institute Co. Ltd.BeijingChina

The high-speed simulation of large-scale offshore wind farms(OWFs) preserving the internal machine information has become a huge challenge due to the large wind turbine(WT) count and microsecond-range time step. Hence, it is undoable to investigate the internal node information of the OWF in the electro-magnetic transient(EMT) programs. To fill this gap,this paper presents an equivalent modeling method for largescale OWF, whose accuracy and efficiency are guaranteed by integrating the individual devices of permanent magnet synchronous generator(PMSG) based WT. The node-elimination algorithm is used while the internal machine information is recursively updated. Unlike the existing aggregation methods, the developed EMT model can reflect the characteristics of each WT under different wind speeds and WT parameters without modifying the codes. The access to each WT controller is preserved so that the time-varying dynamics of all the WTs could be simulated. Comparisons of the proposed model with the detailed model in PSCAD/EMTDC have shown very high precision and high efficiency. The proposed modeling procedures can be used as reference for other types of WTs once the structures and parameters are given.

关键词： Offshore wind farm(OWF) electro-magnetic transient(EMT) integrated equivalent modelling permanent magnet synchronous generator(PMSG)based wind turbine(WT)