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A novel DOA estimation algorithm using directional antennas in cylindrical conformal arrays

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Defence Technology（防务技术） 2021年第3期17卷 1042-1051页

作者： Xiao-feng Gao Ping li Xin-hong Hao guo-lin li Zhi-jie Kong Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing100081China China Academy of Launch Vehicle Technology Beijing100076China

In this paper, a novel direction of arrival(DOA) estimation algorithm using directional antennas in cylindrical conformal arrays(CCAs) is proposed. To eliminate the shadow effect, we divide the CCAs into several subarrays to obtain the complete output vector. Considering the anisotropic radiation pattern of a CCA, which cannot be separated from the manifold matrix, an improved interpolation method is investigated to transform the directional subarray into omnidirectional virtual nested arrays without non-orthogonal perturbation on the noise vector. Then, the cross-correlation matrix(CCM) of the subarrays is used to generate the consecutive co-arrays without redundant elements and eliminate the noise vector. Finally, the full-rank equivalent covariance matrix is constructed using the output of co-arrays,and the unitary estimation of the signal parameters via rotational invariance techniques(ESPRIT) is performed on the equivalent covariance matrix to estimate the DOAs with low computational complexity. Numerical simulations verify the superior performance of the proposed algorithm, especially under a low signal-to-noise ratio(SNR) environment.

关键词： Direction of arrival(DOA) Conformal antenna array Interpolation technique Nested array

Risk factor analysis of perioperative mortality after ruptured bleeding in hepatocellular carcinoma

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World Journal of Gastroenterology 2014年第40期20卷 14921-14926页

作者： Hao-Ming lin li-Ming Lei Jie Zhu guo-lin li Jun Min Department of Hepatobiliary Surgery Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University ICU of Cardiac Surgery Guangdong General Hospital Department of Emergency Surgery Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University

AIM: To discuss strategies and prognosis for the emergency treatment of ruptured bleeding in primary hepatocellular carcinoma.

关键词： Hepatocellular carcinoma Spontaneous rupture liver resection

Presentation of the Berry-Tabor conjecture in Levy plates

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Chinese Physics B 2024年第10期33卷 240-247页

作者： Chao li guo-lin Hou School of Mathematical Sciences Inner Mongolia UniversityHohhot 010021China

The Berry-Tabor(BT)conjecture is a famous statistical inference in quantum chaos,which not only establishes the spectral fluctuations of quantum systems whose classical counterparts are integrable but can also be used to describe other wave *** this paper,the BT conjecture has been extended to Lévy *** predicted by the BT conjecture,level clustering is present in the spectra of Lévy *** consequence of level clustering is studied by introducing the distribution of nearest neighbor frequency level spacing ratios P(r),which is calculated through the analytical solution obtained by the Hamiltonian *** work investigates the impact of varying foundation parameters,rotary inertia,and boundary conditions on the frequency spectra,and we find that P(r)conforms to a Poisson distribution in all *** reason for the occurrence of the Poisson distribution in the Lévy plates is the independence between modal frequencies,which can be understood through mode functions.

关键词： Berry-Tabor conjecture frequency spectra Hamiltonian approach Lévy plates

Machine learning model based on non-convex penalized huberized-SVM

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Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang Ji guo lin-Feng li School of Finance and Economics Xizang Minzu UniversityXianyang712082China Research Center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

Ferroelectric-controlled graphene plasmonic surfaces for all-optical neuromorphic vision

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Science China(Technological Sciences) 2024年第3期67卷 765-773页

作者： CHEN JianBo liU Yu li ShangDong lin lin li YaDong HUANG Wen guo JunXiong School of Electronic Information and Electrical Engineering Institute for Advanced StudyChengdu UniversityChengdu 610106China School of Integrated Circuits Tsinghua UniversityBeijing 100084China School of Integrated Circuits(National Exemplary Schoolof Microelectronics) Universityof Electronic Science and Technologyof China Chengdu 610054China Jincheng Research Institute of Opto-mechatronics Industry Jincheng 048000China Shanxi Key Laboratory of Advanced Semiconductor Optoelectronic Devices and Integrated Systems Jincheng 048000China Engineering Research Center of Digital Imaging and Display Ministry of EducationSoochow UniversitySuzhou 215006China

Artificial visual systems can recognize desired objects and information from complex environments, and are therefore highly desired for pattern recognition, object detection, and imaging applications. However, state-of-the-art artificial visual systems with high recognition performances that typically consist of electronic devices face the challenges of requiring huge storage space and high power consumption owing to redundant data. Here, we report a terahertz(THz) frequency-selective surface using a graphene split-ring resonator driven by ferroelectric polarization for efficient visual system applications. The downward polarization of the ferroelectric material offers an ultrahigh electrostatic field for doping p-type graphene with an anticipated Fermi level. By optimizing the geometric parameters of the devices and modulating the carrier behaviors of graphene, our plasmonic devices exhibit a tunable spectral response in a range of 1.7–6.0 THz with continuous transmission values. The alloptical neural network using graphene plasmonic surfaces designed in this study exhibited excellent performance in visual preprocessing and convolutional filtering and achieved an ultrahigh recognition accuracy of up to 99.3% in training the Modified National Institute of Standards and Technology(MNIST) handwritten digit dataset. These features demonstrate the great potential of graphene plasmonic devices for future smart artificial vision systems.

关键词： graphene plasmon ferroelectric frequency selective surface artificial vision system

Engineering Ru（N^N）3-modified covalent organic framework for photocatalytic olefin epoxidation

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Science China Chemistry 2024年第11期67卷 3719-3728页

作者： Yan-lin li Sheng-li Huang guo-Yu Yang Key Laboratory of Cluster Science (Ministry of Education) Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion MaterialsSchool of Chemistry and Chemical Engineering Beijing Institute of Technology

Photocatalytic olefin oxidation using air as an oxidant is an environmentally friendly method for producing epoxides. Covalent organic frameworks（COFs） have emerged as promising photocatalysts in various organic synthesis reactions. The combination of tri-（2-pyridinal aldehyde）-containing precursor with 4,4’,4’’-（1,3,5-triazine-2,4,6-triyl）trianiline generated（N^N）-I-COF. Via imine-to-quinoline transformation and coordination anchorage of Ru（N^N）3unit, Ru（N^N）3@Q-COF was obtained with improved chemical stability, skeleton conjugation, and novel photochemical characteristics, and demonstrated excellent photocatalytic activity in olefin epoxidation with a wide range of substrates. The presence of H2O played a crucial role in the formation of reactive oxygen species（ROSs）, which in turn influenced the olefin oxidation process. The hydrophilicity of Ru（N^N）3facilitated the approach of H2O and O2to the photogenerated charges, thereby promoting ROSs generation. The lipophilicity of Q-COF allowed for the absorption of olefin substrates, and its nano-channels increased encountering possibility between olefins and ROSs. Consequently, Ru（N^N）3@Q-COF provided an intriguing platform for olefin photooxidation and could be recycled multiple times without any degradation in performance. This report revealed that the conversion of classical ROSs into less potent oxidants with rapid kinetic rates played a crucial role in achieving highly efficient and selective epoxidation of terminal olefins.

关键词： polypyridyl Ru covalent organic framework olefin epoxidation photocatalysis

Stabilizing iridium sites via interface and reconstruction regulations for water oxidation in alkaline and acidic media

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Journal of Energy Chemistry 2024年第2期89卷 355-363,I0009页

作者： Weibin Chen Yanhui Song Lei li Junjie guo Zhan lin Guangdong Provincial Key Laboratory of Plant Resources Biorefinery School of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina Key Laboratory of Interface Science and Engineering in AdvancedMaterials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024ShanxiChina

Exploring effective iridium(Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction(OER).Herein,we regulated the incorporation manner of Ir in Co_(3)O_(4)support to stabilize the Ir sites for effective *** anchored on the surface of Co_(3)O_(4)in the form of Ir(OH)_6 species,the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir *** doped into Co_(3)O_(4)lattice,the analyses of X-ray absorption spectroscopy,in-situ Raman,and OER measurements show that the partially replacement of Co in Co_(3)O_(4)by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface,and simultaneously master the reconstruction effect to mitigate Ir dissolution,realizing the improved OER activity and stability in alkaline and acidic *** a result,Ir_(lat)@Co_(3)O_(4)with Ir loading of 3.67 wt%requires 294±4 mV/285±3 mV and 326±2 mV to deliver 10 mA cm^(-2)in alkaline(0.1 M KOH/1.0 M KOH)and acidic(0.5 M H_(2)SO_(4))solution,respectively,with good stability.

关键词： Interface effect Reconstruction Ir dissolution Ir-O-Co Oxygen evolution reaction

Stable stripe and vortex solitons in two-dimensional spin-orbit coupled Bose-Einstein condensates

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Communications in Theoretical Physics 2024年第6期76卷 26-33页

作者： Yuan guo Muhammad Idrees Ji lin Hui-jun li Institute of Nonlinear Physics and Department of Physics Zhejiang Normal UniversityJinhua 321004China Zhejiang Institute of Photoelectronics and Zhejiang Institute for Advanced light Source Zhejiang Normal UniversityJinhua 321004China

We present a flexible manipulation and control of solitons via Bose-Einstein *** the presence of Rashba spin-orbit coupling and repulsive interactions within a harmonic potential,our investigation reveals the numerical local solutions within the *** manipulating the strength of repulsive interactions and adjusting spin-orbit coupling while maintaining a zero-frequency rotation,diverse soliton structures emerge within the *** include plane-wave solitons,two distinct types of stripe solitons,and odd petal solitons with both single and double *** stability of these solitons is intricately dependent on the varying strength of spin-orbit ***,stripe solitons can maintain a stable existence within regions characterized by enhanced spin-orbit coupling while petal solitons are unable to sustain a stable existence under similar *** rotational frequency is introduced to the system,solitons undergo a transition from stripe solitons to a vortex array characterized by a sustained *** rotational directions of clockwise and counterclockwise are non-equivalent owing to spin-orbit *** a result,the properties of vortex solitons exhibit significant variation and are capable of maintaining a stable existence in the presence of repulsive interactions.

关键词： Bose-Einstein condensate spin-orbit coupling rotation frequency stripe solitons vortex array

Electrochemical Cascade Annulation for the Synthesis of 3-Sulfanylquinoline Derivatives under Mild Conditions

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Chinese Journal of Chemistry 2024年第16期42卷 1833-1838页

作者： Ke li Ming-Zhong guo Zhuo Chen Hao-Ran li Weisi guo Ming li lin-Bao Zhang State Key Laboratory Base of Eco-Chemical Engineering College of Chemistry and Molecular EngineeringQingdao University of Science&TechnologyQingdaoShandong 266042China

An efficient electrochemical approach has been developed for the construction of 3-sulfanylquinoline derivatives by treating phenylethynylbenzoxazinanones with disulfides in an undivided *** protocol provided a convenient route to functionalized quinolines with good functional group ***,it does not require any metal catalysts or additives,furnishing a series of biologicalquinolines inmoderatetogoodyields.

关键词： Electrocatalysis Electrooxidation Annulation 3-Sulfany quinoline C3-thioetherification