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Search Results: 1 - 10 of 127170 matches for " Xianhui Li "
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XPS CHARACTERIZATION AND PERCOLATION BEHAVIOR OF POLYANILINE-COATED CONDUCTIVE PAPER
Jian Li,Xueren Qian,Lijuan Wang,Xianhui An
BioResources , 2010,
Abstract: Polyaniline (PAn)-coated conductive paper was prepared by in-situ polymerization of aniline and a two-step process. XPS results confirmed that the bond between PAn and cellulose existed in the form of hydrogen bonding. The mild treatment did not result in the oxidation and degradation of cellulose. Decreased bonding strength of conductive paper was attributed to the coverage of hydroxyl groups on pulp fibers by PAn. For the PAn-coated paper about one in every three nitrogen atoms was doped with p-toluenesulfonic acid (PTSA). The quinoid imine nitrogens of the PAn molecular chain were preferentially doped. Pulp fibers seemed to be favorable for the doping of PAn with PTSA. The surface resistivity sharply decreased at least two orders of magnitude with a very small increase in the amount of PAn coated (from 3.6% to 4.2%). A continuous conductive network was formed and the surface resistivity was lowest when the amount of PAn coated reached 30.1%. The upper and lower threshold values were around 4% and 30%, respectively. SEM study showed that the shape of the PAn coated on pulp fibers was spherical with a diameter from 100 to 200 nm.
A Hybrid LSSVR/HMM-Based Prognostic Approach
Zhijuan Liu,Qing Li,Xianhui Liu,Chundi Mu
Sensors , 2013, DOI: 10.3390/s130505542
Abstract: In a health management system, prognostics, which is an engineering discipline that predicts a system’s future health, is an important aspect yet there is currently limited research in this field. In this paper, a hybrid approach for prognostics is proposed. The approach combines the least squares support vector regression (LSSVR) with the hidden Markov model (HMM). Features extracted from sensor signals are used to train HMMs, which represent different health levels. A LSSVR algorithm is used to predict the feature trends. The LSSVR training and prediction algorithms are modified by adding new data and deleting old data and the probabilities of the predicted features for each HMM are calculated based on forward or backward algorithms. Based on these probabilities, one can determine a system’s future health state and estimate the remaining useful life (RUL). To evaluate the proposed approach, a test was carried out using bearing vibration signals. Simulation results show that the LSSVR/HMM approach can forecast faults long before they occur and can predict the RUL. Therefore, the LSSVR/HMM approach is very promising in the field of prognostics.
Impact of the Fe Doping on Magnetism in Perovskite Cobaltites
Xigang Luo,Wendong Xing,Zhaofeng Li,Gang Wu,Xianhui Chen
Physics , 2007,
Abstract: We systematically studied the magnetic and transport properties for the polycrystalline samples of Fe-doped perovskite cobaltites: Pr$_{1-y}$Ca$_{y}$Co$_{1-x}$Fe$_x$O$_3$ ($y$=0.3, $x$=0-0.15; $y$=0.45, $x$=0-0.3) and Gd$_{0.55}$Sr$_{0.45}$Co$_{1-x}$Fe$_x$O$_{3}$ ($x$=0-0.3). Fe doping leads to an enhancement of the ferromagnetism in the systems of Pr$_{1-y}$Ca$_{y}$Co$_{1-x}$Fe$_x$O$_3$, while the ferromagnetism is suppressed with further increasing Fe content and spin-glass behavior is observed at high doping level of Fe. In contrast, the ferromagnetism is suppressed in the system Gd$_{0.55}$Sr$_{0.45}$Co$_{1-x}$Fe$_x$O$_{3}$ as long as Fe is doped, and no spin-glass behavior is observed in the sample with Fe doping up to 0.3. The competition between ferromagnetic interactions through Fe$^{3+}$-O-(LS)Co$^{4+}$ and antiferromagnetic interactions through Fe$^{3+}$-O-Fe$^{3+}$ and Fe$^{3+}$-O-(IS)Co$^{3+}$ is considered to be responsible for the behavior observed above. The average radius of the ions on A sites plays the key role in determining what type of interactions Fe doping mainly introduces.
Nonexistence of the Longitudinal Polarisation of a Massive Gauge Bosons
Ze-sen Yang,Xianhui Li,Weizhen Deng,Xiaolin Chen
Physics , 2000,
Abstract: This paper has been withdrawn by the authors due to some errors.
Renormalisability of the SU(2)$\times$U(1) Electroweak Theory with Massive W Z Fields and Massive Matter Fields
Ze-sen Yang,Xianhui Li,Weizhen Deng,Xiaolin Chen
Physics , 2000,
Abstract: We extend the previous work and study the renormalisability of the SU$_L$(2) $\times$ U$_Y$(1) electroweak theory with massive W Z fields and massive matter fields. We expound that with the constraint conditions caused by the W Z mass term and the additional condition chosen by us we can still performed the quantization in the same way as before. We also show that when the $\delta-$ functions appearing in the path integral of the Green functions and representing the constraint conditions are rewritten as Fourier integrals with Lagrange multipliers $\lambda_a$ and $\lambda_y$, the total effective action consisting of the Lagrange multipliers, ghost fields and the original fields is BRST invariant. Furthermore, with the help of the the renormalisability of the theory without the the mass term of matter fields, we find the general form of the divergent part of the generating functional for the regular vertex functions and prove the renormalisability of the theory with the mass terms of the W Z fields and the matter fields.
BRST Invariance and Renormalisability of the SU(2)$\times$U(1) Electroweak Theory with Massive W Z Bosons
Ze-sen Yang,Xianhui Li,Zhinig Zhou,Yushu Zhong
Physics , 2000,
Abstract: Since the SU(n) gauge theory with massive gauge bosons has been proven to be renormalisable we reinvestigate the renormalisability of the SU$_L$(2) $\times$ U$_Y$(1) electroweak theory with massive W Z bosons. We expound that with the constraint conditions caused by the W Z mass term and the additional condition chosen by us we can performed the quantization and construct the ghost action in a way similar to that used for the massive SU(n) theory. We also show that when the $\delta-$ functions appearing in the path integral of the Green functions and representing the constraint conditions are rewritten as Fourier integrals with Lagrange multipliers $\lambda_a$ and $\lambda_y$, the BRST invariance is kept in the total effective action consisting of the Lagrange multipliers, ghost fields and the original fields. Furthermore, by comparing with the massless theory and with the massive SU(n) theory we find the general form of the divergent part of the generating functional for the regular vertex functions and prove the renormalisability of the theory. It is also clarified that the renormalisability of the theory with the W Z mass term is ensured by that of the massless theory and the massive SU(n) theory.
Renormalisability of the SU(n) Gauge Theory with Massive Gauge Bosons
Ze-sen Yang,Zhining Zhou,Yushu Zhong,Xianhui Li
Physics , 1999,
Abstract: The problem of renormalisability of the SU(n) theory with massive gauge bosons is reinverstigated in the present work. We expound that the quantization under the Lorentz condition caused by the mass term of the gauge fields leads to a ghost action which is the same as that of the usual SU(n) Yang-Mills theory in the Landau gauge. Furthermore, we clarify that the mass term of the gauge fields cause no additional complexity to the Slavnov-Taylor identity of the generating functional for the regular vertex functions and does not change the equations satisfied by the divergent part of this generating functional. Finally, we prove that the renormalisability of the theory can be deduced from the renormalisability of the Yang-Mills theory.
Scattering Matrix of the SU(n) Gauge Theory with Explicit Gauge Mass Term
Yang Ze-sen,Li Xianhui,Zhou Zhining,Zhong Yushu
Physics , 1999,
Abstract: Based on the renormalisability of the SU(n) theory with massive gauge bosons, we start with the path integral of the generating functional for the renormalized Green functions and develop a method to construct the scattering matrix so that the unitarity is evident. By using as basical variables the renormalized field functions and defining the unperturbed Hamiltonian operator $H_0$ that, under the Lorentz condition, describes the free particles of the initial and final states in scattering processes, we form an operator description with which the renormalized Green functions can be expressed as the vacuum expectations of the time ordered products of the Heisenberg operators of the renormalized field functions, that satisfy the usual equal time commutation or anticommutation rules. From such an operator description we find a total Hamiltonian $\widetilde{H}$ that determine the time evolution of the Heisenberg operators of the renormalized field functions. The scattering matrix is nothing but the matrix of the operator $U(\infty, -\infty)$, which describes the time evolution from $-\infty$ to $\infty$ in the interaction picture specified by $\widetilde{H}$ and $H_0$, respect to a base formed by the physical eigen states of $H_0$. We also explain the asymptotic field viewpoint of constructing the scattering matrix within our operator description. Moreover, we find a formular to express the scattering matrix elements in terms of the truncated renormalized Green functions.
Initial-Final State Subspace of the SU(n) Gauge Theory with Explicit Gauge Field Mass Term
Ze-sen Yang,Xianhui Li,Xiaolin Chen
Physics , 2000,
Abstract: As a part of our study on the SU(n) gauge theory with explicit gauge field mass term this paper is devoted to form the Gupta-Bleuler subspace of the initial-final states in the scattering process.
NUMERICAL SIMULATION OF SURFACE CRACK PROPAGATION FOR GLASS
玻璃表面裂纹扩展的数值模拟

HUANG Li,SONG Xianhui,
黄莉
,宋显辉,彭立华,沈为

材料研究学报 , 1996,
Abstract: In this paper we have prepared controllble surface cracks on glasss pecimens and measured the extension data along crack length. By themethod of crack extension resistance curve a numerical simulationon the surface crack extension is made and the data on the crack depth andthe ration of depth to length are obtained respectively, providing the basis for deeply understanding the propagation proccess of surface cracks.
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