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New insights into disruption of iron homeostasis by environmental pollutants

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Journal of Environmental Sciences 2015年第8期27卷 256-258页

作者： xiang wang Tian Xia Department of Medicine Division of Nano Medicine University of California California Nano Systems Institute University of California

Among the numerous health conditions environmental pollutants can cause, chronic exposure to pollutants including persistent organic pollutants（POPs） and heavy metals has been shown to disturb a specific biological homeostatic process, the iron metabolism in human body. Disorders of iron metabolism are among the common diseases of humans and encompass a broad spectrum of diseases with different clinical manifestations, ranging from anemia to iron overload, and possibly to neurodegenerative diseases and ***–ferroportin（FPN） signaling is one of the key mechanisms responsible for iron supply, utilization, recycling, and storage, and recent studies demonstrated that exposure to environmental pollutants including POPs and heavy metals could lead to disruption of the hepcidin–FPN axis along with disordered systemic iron homeostasis and diseases. This article introduces and highlights the accompanying review article by Drs. Xu and Liu in this journal, which elaborates in detail the adverse effects of environmental pollutants on iron metabolism, and the mechanisms responsible for these toxicological outcomes. It also points out the knowledge gaps still existing in this subject matter. Research that will fill these gaps will improve our understanding of the issue and provide useful information to prevent or treat diseases induced by environmental pollutants.

关键词： Environmental pollution Persistent organic pollutants Heavy metals Iron homeostasis Hepcidin Ferroportin

High Chern number phase in topological insulator multilayer structures:A Dirac cone model study

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Chinese Physics B 2022年第9期31卷 217-224页

作者： Yi-xiang wang Fu-xiang Li School of Science Jiangnan UniversityWuxi 214122China School of Physics and Electronics Hunan UniversityChangsha 410082China

We employ the Dirac cone model to explore the high Chern number(C)phases that are realized in the magnetic-doped topological insulator(TI)multilayer structures by Zhao et al.[Nature 588419(2020)].The Chern number is calculated by capturing the evolution of the phase boundaries with the parameters,then the Chern number phase diagrams of the TI multilayer structures are *** high-C behavior is attributed to the band inversion of the renormalized Dirac cones,along with which the spin polarization at theΓpoint will get ***,another two TI multilayer structures as well as the TI superlattice structures are studied.

关键词： topological insulator multilayer Chern number phase diagram

Gray codes over certain run-length sequences for local rank modulation

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Science China(Information Sciences) 2018年第10期61卷 98-113页

作者： xiang wang Fang-Wei FU National Computer Network Emergency Response Technical Team The Chern Institute of Mathematics and LPMC Nankai University

In the local rank modulation(LRM) scheme, a sliding window produces a sequence of permutations by moving over a sequence of variables. LRM has been presented as a method of storing data in flash memory, which represents a natural generalization of the classical rank modulation scheme. In this paper, we present a study on Gray codes over certain run-length sequences for the(1, 2, n)-LRM scheme to simulate virtual multilevel flash memory cells while maintaining the advantages of LRM. Unlike previous studies on the LRM scheme, we present Gray codes over certain run-length sequences in the(1, 2, n)-LRM scheme. This class of Gray codes can overcome the drawback of the many distinct charge levels required in the rank modulation scheme and in certain Gray codes for LRM. Furthermore, we demonstrate that the proposed codes have an asymptotically optimal rate.

关键词： flash memory local rank modulation Gray codes rank modulation run-length sequences

Unintentional modulation microstructure enlargement

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Journal of Systems Engineering and Electronics 2022年第3期33卷 522-533页

作者： SUN Liting wang xiang HUANG Zhitao Department of Electronic Science National University of Defense TechnologyChangsha 410073China

Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific *** RFF-related information is mainly in the form of unintentional modulation(UIM),which is subtle enough to be effectively imperceptible and is submerged in the intentional modulation(IM).It is necessary to minimize the influence of the IM and expand the slight differences between emitters for successful *** paper proposes a UIM microstructure enlargement(UMME)method based on feature-level adaptive signal decomposition(ASD),accompanied by autocorrelation and cross-correlation *** common IM part is evaluated by analyzing a newly-defined benchmark *** different indexes are used to quantify the similarity,distance,and dependency of the RFF features from different *** are conducted based on the real-world signals transmitted from 20 of the same type of radar in the same working *** visual image qualitatively shows the magnification of feature differences;different indicators quantitatively describe the changes in *** with the original RFF feature,recognition results based on the Gaussian mixture model(GMM)classifier further validate the effectiveness of the proposed algorithm.

关键词： radio frequency fingerprinting(RFF) unintentional modulation(UIM) adaptive signal decomposition(ASD) variational mode decomposition(VMD) similarity measurement

Unintentional modulation evaluation in time domain and frequency domain

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Chinese Journal of Aeronautics 2022年第4期35卷 376-389页

作者： Liting SUN xiang wang Zhitao HUANG Department of Electronic Science National University of Defense Technology410073 ChangshaChina

With the development of wireless communication technology, the electromagnetic environment has become more and more complex. Conventional signal identification methods are difficult to accurately identify illegal devices. However, electromagnetic signals have an unavoidable device-specific characteristic unintentionally generated by a transmitter, appearing in the form of an Un Intentional Modulation(UIM), namely Radio Frequency Fingerprint(RFF). RFFs can be used to uniquely identify an emitter to match a received signal with its source. In this paper, the authors propose a novel RFF scheme to separate UIM part from the original signals from the time and frequency domain, and then utilize non-Gaussian measuring tools to extract a set of dimensionreduced secondary features. Additionally, Singular Value Reconstruction(SVR) is developed to extract UIM in the frequency spectrum. In time domain, a curve-fitting residual method is proposed to extract the UIM on the estimated instantaneous phase based on Maximum Likelihood Estimator(MLE). Various aspects of the proposed method are evaluated, including identification accuracy under various Signal-to-Noise Ratio(SNR) conditions, energy relationships between the UIM and the whole signal, and sensitivity to training set size. Compared with other methods, experimental results based on real-world signals prove that the proposed method has remarkable performance and high practicability.

关键词： Instantaneous phase estimation Pattern recognition Radio Frequency Fingerprint(RFF) Singular Value Decomposition(SVD) Un Intentional Modulation(UIM)

Underdetermined DOA estimation via multiple time-delay covariance matrices and deep residual network

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Journal of Systems Engineering and Electronics 2021年第6期32卷 1354-1363页

作者： CHEN Ying wang xiang HUANG Zhitao State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense TechnologyChangsha 410073China

Higher-order statistics based approaches and signal sparseness based approaches have emerged in recent decades to resolve the underdetermined direction-of-arrival(DOA)estimation *** model-based methods face great challenges in practical applications due to high computational complexity and dependence on ideal *** paper presents an effective DOA estimation approach based on a deep residual network(DRN)for the underdetermined *** first extract an input feature from a new matrix calculated by stacking several covariance matrices corresponding to different time *** then provide the input feature to the trained DRN to construct the super resolution *** DRN learns the mapping relationship between the input feature and the spatial spectrum by *** proposed approach is superior to existing model-based estimation methods in terms of calculation efficiency,independence of source sparseness and adaptive capacity to non-ideal conditions(e.g.,low signal to noise ratio,short bit sequence).Simulations demonstrate the validity and strong performance of the proposed algorithm on both overdetermined and underdetermined cases.

关键词： direction-of-arrival(DOA)estimation underdetermined condition deep residual network(DRN) time delay covariance matrix

Kinetic study of hydrodesulfurization of coker gas oil in a slurry reactor

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Frontiers of Chemical Science and Engineering 2013年第2期7卷 139-144页

作者： Haiding xiang Tiefeng wang Beijing Key Laboratory of Green Reaction Engineering and Technology Department of Chemical Engineering Tsinghua University Beijing 100084 China

Coker gas oil （CGO） is a poor-quality feed- stock for ftuidized bed catalytic cracking （FCC） or hydrocracking. The pretreatment of CGO, especially hydrotreating, can significantly improve the product quality and protect the catalyst. In this work, we studied the hydrodesulfurization （HDS） of CGO in a slurry reactor. All the experiments were carried out in an autoclave using a NiMo/A1203 catalyst at reaction temperature 340℃- 400℃, pressure 6-10 MPa, and stirring speed 800 r. mn^-1, with hydrogen-to-oil ratio in the range of 500-1500. The effects of the operating parameters on the desulfurization ratio were investigated and discussed. A macro reaction kinetic model was established for the HDS of CGO in the slurry reactor.

关键词： coker gas oil hydrodesulfurization slurryreactor reaction kinetic model

On the Construction and Analysis of Finite Volume Element Schemes with Optimal L^(2) Convergence Rate

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Numerical Mathematics(Theory,Methods and Applications) 2021年第1期14卷 47-70页

作者： xiang wang Yuqing Zhang School of Mathematics Jilin UniversityChangchun 130012China

We provide a general construction method for a finite volume element(FVE)scheme with the optimal L^(2)convergence *** k-(k-1)-order orthogonal condition(generalized)is proved to be a sufficient and necessary condition for a k-order FVE scheme to have the optimal L^(2) convergence rate in 1D,in which the independent dual parameters constitute a(k-1)-dimension surface in the reasonable domain in *** the analysis,the dual strategies in different primary elements are not necessarily to be the same,and they are allowed to be asymmetric in each primary element,which open up more possibilities of the FVE schemes to be applied to some complex problems,such as the convection-dominated *** worth mentioning that,the construction can be extended to the quadrilateral meshes in *** stability and H^(1) estimate are proved for *** the above results are demon-strated by numerical experiments.

关键词： Finite volume L^(2)estimate sufficient and necessary condition orthogonal condition

Solutions for Schrodinger-Poisson system involving nonlocal term and critical exponent

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Applied Mathematics(A Journal of Chinese Universities) 2023年第3期38卷 357-372页

作者： MO Xiu-ming MAO An-min wang xiang-xiang School of Biomedicine Beijing City UniversityBeijing 100094China School of Mathematical Sciences Qufu Normal UniversityQufu 273165China.

In this paper,we consider the following Kirchhoff-Schrodinger-Poisson system:{−(a+b∫_(R^(3))|∇u|^(2))△u+u+ϕu=μQ(x)|u|^(q-2)u+K(x)|u|^(4)u,in R^(3),−△ϕ=u^(2) the nonlinear growth of|u|^(4)u reaches the Sobolev critical *** combining the variational method with the concentration-compactness principle of Lions,we establish the existence of a positive solution and a positive radial solution to this problem under some suitable *** nonlinear term includes the nonlinearity f(u)~|u|^(q-2)u for the well-studied case q∈[4,6),and the less-studied case q∈(2,3),we adopt two different strategies to handle these *** result improves and extends some related works in the literature.

关键词： variational methods critical exponent concentration-compactness principle