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Quantized innovations Kalman filter: stability and modification with scaling quantization

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第2期13卷 118-130页

作者： jian XU jian-xun LI Sheng XU Science and Technology on Avionics Integration Laboratory Shanghai Jiao Tong UniversityShanghai 200240 MOE Key Laboratory of System Control and Information Processing Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The stability of quantized innovations Kalman filtering (QIKF) is analyzed. In the analysis, the correlation between quantization errors and measurement noises is considered. By taking the quantization errors as a random perturbation in the observation system, the QIKF for the original system is equivalent to a Kalman-like filtering for the equivalent state-observation system. Thus, the estimate error covariance matrix of QIKF can be more exactly analyzed. The boundedness of the estimate error covariance matrix of QIKF is obtained under some weak conditions. The design of the number of quantized levels is discussed to guarantee the stability of QIKF. To overcome the instability and divergence of QIKF when the number of quantization levels is small, we propose a Kalman filter using scaling quantized innovations. Numerical simulations show the validity of the theorems and algorithms.

关键词： Kalman filtering Quantized innovation Stability Scaling quantization Wireless sensor network

Two Kinds of New Lie Algebras for Producing Integrable Couplings

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Communications in Theoretical Physics 2006年第2X期46卷 203-208页

作者： YAN Qing-You QI jian-xun School of Business Administration North China Electric Power University Beijing 102206 China

Two types of Lie algebras are constructed, which are directly used to deduce the two resulting integrable coupling systems with multi-component potential functions. Many other integrable couplings of the known integra... 详细信息

关键词： KN hierarchy integrable couplings Lie algebra loop algebra

Orbifold Gromov–Witten Invariants of Weighted Blow-up at Smooth Points

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Acta Mathematica Sinica,English Series 2015年第5期31卷 825-846页

作者： Wei Qiang HE jian xun HU Department of Mathematics Sun Yat-Sen University

In this paper, one considers the change of orbifold Gromov Witten invariants under weighted blow-up at smooth points. Some blow-up formula for Gromov-Witten invariants of sym- pleetic orbifolds is proved. These result... 详细信息

关键词： Gromov-Witten invariant orbifold weighted blow-up

Wavelet Transform and Radon Transform on the Quaternion Heisenberg Group

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Acta Mathematica Sinica,English Series 2014年第4期30卷 619-636页

作者： jian xun HE He Ping LIU School of Mathematics and Information Sciences Guangzhou University Key Laboratory of Mathematics and Interdisciplinary Sciences of Guangdong Higher Education Institutes Guangzhou University LMAM School of Mathematical SciencesPeking University

Let be the quaternion Heisenberg group, and let P be the affine automorphism group of . We develop the theory of continuous wavelet transform on the quaternion Heisenberg group via the unitary representations of P on L2（）. A class of radial wavelets is constructed. The inverse wavelet transform is simplified by using radial wavelets. Then we investigate the Radon transform on . . A Semyanistyi-Lizorkin space is introduced, on which the Radon transform is a bijection. We deal with the Radon transform on both by the Euclidean Fourier transform and the group Fourier transform. These two treatments are essentially equivalent. We also give an inversion formula by using wavelets, which does not require the smoothness of functions if the wavelet is smooth. In addition, we obtain an inversion formula of the Radon transform associated with the sub-Laplacian on .

关键词： Quaternion Heisenberg group wavelet transform Radon transform inverse Radon transform

Effects of the width and thickness of slabs on broadening in continuous casting

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 723-728页

作者： jian-xun Fu Jing-she Li Hui Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China National Engineering Research Center of Continuous Casting Technology Central Iron and Steel Research Institute Beijing 100081 China

A 3D viscoelastic-plastic thermal-mechanical coupled finite element model was built on the basis of the secondary development of the commercial software ***. Numerical simulations were performed to study slab broadening in the secondary cooling zone. The effects of slab width and thickness on slab broadening were considered. The obtained results reveal that the width broadening is noticeable, and the ratio of ultimate broadening slightly increases with the increase of slab width. This agrees well with the measured data in practice. There is no obvious increase in ultimate broadening when the thickness of slabs increases.

关键词： continuous casting slabs broadening finite element method

Texture Evolution and Dynamic Recrystallization of Zr-1Sn-0.3Nb-0.3Fe-0.1Cr Alloy During Hot Rolling

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Acta Metallurgica Sinica(English Letters) 2020年第2期33卷 215-224页

作者： jian xun Gaoyong Lin Huiqun Liu Siyu Zhao Jing Chen xun Dai Ruiqian Zhang School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Lab of Nonferrous Materials Ministry of EducationCentral South UniversityChangsha 410083China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610213China

In the present work,the sheets of Zr-1Sn-0.3Nb-0.3Fe-0.1Cr alloy were hot rolled with different reductions(10%,30%,50%,and 60%) at 1023 K and 1073 *** micro structure evolutions including grain micro structure,texture,and dislocation were investigated,using electron backscattering diffraction and transmission electron *** results showed that dislocation slip,twinning,and dynamic recrystallization(DRX) were the main deformation *** was found to be promoted by larger reduction and higher rolling *** predominant texture formed during hot rolling was basal //ND,whose intensity reached peak value after 30% reduction hot *** the intensity of DRX texture //ND and//ND increased with increasing reduction and *** study provided an effective way to tailor the texture and microstructure of the alloy,for optimizing process parameters.

关键词： Zr–1Sn–0.3Nb–0.3Fe–0.1Cr alloy Hot rolling Texture evolution Recrystallization

Analysis of precipitation behavior of MnS in sulfur-bearing steel system with finite-difference segregation model

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Journal of Iron and Steel Research International 2018年第8期25卷 803-812页

作者： De-lin Hu Hui Liu jian-bo Xie Juan Cheng jian Li jian-xun Fu State Key Laboratory of Advanced Special Steel and Shanghai Key Laboratory of Advanced Ferrometallurgy and School of Materials Science and Engineering Shanghai University Shanghai 200444 China

To further reveal the influence of micro-segregation on the precipitation behavior of MnS in sulfur-bearing steel system, a coupled model of micro-segregation and MnS precipitation was established by the finite-difference method based on various calculation domains and the solid diffusion degrees, and a new controlled diffusion equation with more stable convergence was also used. 49MnVS3 and 1215 steels were used to analyze the influence of calculation domain, segregation model and S content on the precipitation behavior of MnS. The calculation results were verified by a high- temperature confocal laser scanning microscope （HT-CLSM）. The results show that the domain has little effect on the precipitation temperature, precipitation solid fraction and precipitation amount of MnS, but affects the precipitation location and segregation of the solutes. For low- and medium-sulfur steels, the temperatures calculated by the diffusion control growth （DCG） model and the Lever model were nearly identical, whereas the temperature calculated by the Scheil model was lower. However, for high-sulfur steels, the precipitation temperatures calculated by three segregation models were nearly same. The precipitation solid fraction is more reasonable to describe the precipitation behavior of MnS. The precipitation behavior of MnS, observed by the HT-CLSM, matches well with that in the DCG model.

关键词： MnS precipitation Micro-segregation Mathematical model Solidification In situ observation

Physics-informed deep learning for solving phonon Boltzmann transport equation with large temperature non-equilibrium

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npj Computational Materials 2022年第1期8卷 245-254页

作者： Ruiyang Li jian-xun Wang Eungkyu Lee Tengfei Luo Department of Aerospace and Mechanical Engineering University of Notre DameNotre DameIN46556USA Department of Electronic Engineering Kyung Hee UniversityYongin-siGyeonggi-do17104South Korea Department of Chemical and Biomolecular Engineering University of Notre DameNotre DameIN46556USA Center for Sustainable Energy of Notre Dame(ND Energy) University of Notre DameNotre DameIN46556USA

Phonon Boltzmann transport equation(BTE)is a key tool for modeling multiscale phonon transport,which is critical to the thermal management of miniaturized integrated circuits,but assumptions about the system temperatures(i.e.,small temperature gradients)are usually made to ensure that it is computationally *** include the effects of large temperature non-equilibrium,we demonstrate a data-free deep learning scheme,physics-informed neural network(PINN),for solving stationary,mode-resolved phonon BTE with arbitrary temperature *** scheme uses the temperature-dependent phonon relaxation times and learns the solutions in parameterized spaces with both length scale and temperature gradient treated as input *** experiments suggest that the proposed PINN can accurately predict phonon transport(from 1D to 3D)under arbitrary temperature ***,the proposed scheme shows great promise in simulating device-level phonon heat conduction efficiently and can be potentially used for thermal design.

关键词： phonon equilibrium equation

Dynamic response characteristics of dry and watersaturated schist under impact loading

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Journal of Mountain Science 2020年第12期17卷 3123-3136页

作者： ZHOU Yang SU Sheng-rui CHEN jian-xun School of Geological Engineering and Geomatics Chang’an UniversityXi’an 710064China School of Highway Chang’an UniversityXi’an 710064China

Many geological engineering hazards are closely related to the dynamic mechanical properties of rock ***,most existing studies on the dynamic mechanical properties of rock materials were conducted on the hard rocks such as sandstone,granite,limestone,and marble,whereas soft rocks,such as schist,are less ***,in this study,a series of triaxial impact tests were conducted on dry and saturated schist by employing a modified triaxial split Hopkinson pressure bar system to reveal the coupling effects of water,strain rate,and triaxial confining pressure on the mechanical properties of *** results show that schist is a type of watersensitive rock and the stress-strain curve of saturated schist has apparent *** effects of strain rate on dynamic strain,deformation modulus and peak stress were *** results also show that the dynamic peak stress is affected by the combined softening effect and viscous effect of water under impact ***,it was found that the failure mode of schist belongs to typical axial tensile failure under uniaxial impact tests,and shear failure is the main failure mode under triaxial impact *** the increase in confining pressure,the failure modes of schist change from tensile failure to shear *** research can provide useful parameters for geological engineering hazard prevention in mountain areas.

关键词： Dry and water-saturated schist Triaxial stress constraint Modified triaxial split Hopkinson pressure bar Dynamic mechanical behavior Impact loading