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Study on Coded Permutation Entropy of Finite Length Gaussian White Noise Time Series

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Chinese Journal of Electronics 2024年第1期33卷 185-194页

作者： Huihui SUN Xiaofeng ZHANG school of {1. and information Technology Shaanxi Normal University

As an extension of permutation entropy(PE), coded permutation entropy(CPE) improves the performance of PE by making a secondary division for ordinal patterns defined in PE. In this study, we provide an exploration of the statistical properties of CPE using a finite length Gaussian white noise time series theoretically. By means of the Taylor series expansion, the approximate expressions of the expected value and variance of CPE are deduced and the Cramér-Rao low bound(CRLB) is obtained to evaluate the performance of the CPE estimator. The results indicate that CPE is a biased estimator, but the bias only depends on relevant parameters of CPE and it can be easily corrected for an arbitrary time series. The variance of CPE is related to the encoding patterns distribution,and the value converges to the CRLB of the CPE estimator when the time series length is large enough. For a finitelength Gaussian white noise time series model, the predicted values can match well with the actual values, which further validates the statistic theory of CPE. Using the theoretical expressions of CPE, it is possible to better understand the behavior of CPE for most of the time series.

关键词： Time series analysis White noise Predictive models Taylor series Entropy Encoding Time measurement

Exploring dark matter-gauge boson effective interactions at current and future colliders

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Chinese physics C 2024年第6期48卷 58-68页

作者：张宇黄祎伟张伟涛宋昴丁然 Institutes of Physical Science and information Technology Anhui UniversityHefei 230601China school of {1. Hefei University of TechnologyHefei 230601China school of {1. and optoelectronics Engineering Anhui UniversityHefei 230601China

In this study,we systematically investigate collider constraints on effective interactions between Dark Matter(DM)particles and electroweak gauge *** consider the simplified models in which scalar or Dirac fermion DM candidates couple only to electro weak gauge bosons through high dimensional effective *** the induced DM-quarks and DM-gluons operators from the Renormalization Group Evolution(RGE)running effect,we present comprehensive constraints on the effective energy scaleΛand Wilson coefficients CB(Λ),CW(Λ)from direct detection,indirect detection,and collider *** particular,we present the corresponding sensitivity from the Large Hadron Electron Collider(LHeC)and Future Circular Collider in the electronproton mode(FCC-ep)for the first time,update the mono-j and mono-γsearch limits at the Large Hadron Collider(LHC),and derive the new limits at the Circular Electron Positron Collider(CEPC).

关键词： dark matter effective field theory LHC CEPC LHeC FCC-ep

A visible-light-assisted Pd/TiO_(2)gas sensor with carbon nanotubes electrodes for trace formaldehyde detection

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Rare Metals 2024年第1期43卷 257-266页

作者： Can Liu Qiao-Qiao Zou Bin Liu Yong Zhang school of {1. and optoelectronics Xiangtan UniversityXiangtan 411105China Hunan Institute of Advanced Sensing and information Technology Xiangtan UniversityXiangtan 411105China school of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China

Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment ***,the traditional resistive gas sensors hardly meet the requirement due to the weak signal generated by trace gas molecules that are difficult to ***,a visible-light-assisted Pd/TiO_(2)gas sensor is proposed to endow the effective detection of trace formaldehyde(HCHO)gas without heating *** from the enhanced photocatalytic properties of TiO_(2)by Pd decoration,the visible-light-assisted Pd/TiO_(2)gas sensor can detect the HCHO gas as low as80×1.^(–9)at room *** successful preparation of nanoscale TiO_(2)sensing layer is facilitated by the ultrathin carbon nanotube interdigital electrode in the gas sensor,which avoids the discontinuity of the sensing layer caused by the excessive thickness of the traditional metal *** addition,the whole preparation process of the Pd/TiO_(2)gas sensor with carbon nanotube electrodes is compatible with mainstream CMOS fabrication technology,which is expected to realize the batch fabrication and micro-integrated application of gas *** is expected that our work can provide a new strategy for the batch preparation of high-performance trace HCHO gas sensors and their future applications in portable electronic devices such as smartphones.

关键词： Visible-light-assisted gas sensor Pd/TiO_(2) Trace HCHO detection Carbon nanotubes electrodes

Robust optical mode converter based on topological waveguide arrays

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Chinese physics B 2024年第6期33卷 197-203页

作者：徐宇翔唐文剑姜力炜吴德兴王恒许冰聪陈林 Wuhan National Laboratory for optoelectronics and {1. of Optical and Electronic information Huazhong University of Science and TechnologyWuhan 430074China

Optical mode converters are essential for enhancing the capacity of optical communication systems. However, fabrication errors restrict the further improvement of conventional mode converters. To address this challenge, we have designed an on-chip TE0–TE1.ode converter based on topologically protected waveguide arrays. The simulation results demonstrate that the converter exhibits a mode coupling efficiency of 93.5% near 1.50 nm and can tolerate a relative fabrication error of 30%. Our design approach can be extended to enhance the robustness for other integrated photonic devices, beneficial for future development of optical network systems.

关键词： on-chip integrated photonic devices topological photonics mode converter robustness

Mechanical and magnetocaloric adjustable properties of Fe3O4/PET deformed nanoparticle film

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Chinese physics B 2024年第3期33卷 589-595页

作者：范凤国段林彤 school of {1. and Electrical information Shangqiu Normal UniversityShangqiu 476000China

The flexibility of nanoparticle films is a topic of rapidly growing interest in both scientific and engineering researches due to their numerous potential applications in a broad range of wearable electronics and biomedical *** article presents the elucidation of the properties of nanoparticle ***,a flexible film is fabricated based on polyethylene terephthalate(PET)and magnetic iron oxide at the nanoscale using layer-by-layer *** 2D thin flexible film material can be bent at different angles from 0°to 360°.With an increase in elastic deformation angles,the magnetocaloric effect of the film gradually increases in the alternating magnetic *** test results from a vibrating sample magnetometer and a low-frequency impedance analyzer demonstrate that the film has a good magnetic response and *** magnetocaloric effect and magnetic induction effect are controlled by deformation,providing a new idea for the application of elastic *** combines the flexibility of the nanoparticle PET substrate and,in the future,it may be used for skin adhesion for administration and magnetic stimulation control.

关键词： nanoparticle film deformation magnetic properties flexible substrates

Asymmetric frequency multiplexing topological devices based on a floating edge band

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Photonics Research 2024年第6期12卷 1201-1212页

作者： JIAJUN MA CHUNMEI OUYANG YUTING YANG DONGYANG WANG HONGYI LI LI NIU YI LIU QUAN XU YANFENG LI ZHEN TIAN JIAGUANG HAN WEILI ZHANG Center for Terahertz Waves and College of Precision Instrument and optoelectronics Engineering and Key Laboratory of Optoelectronics Information and TechnologyTianjin UniversityTianjin 300072China school of Materials Science and {1. China University of Mining and TechnologyXuzhou 221116China optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK Guangxi Key Laboratory of Optoelectronic information Processing School of Optoelectronic EngineeringGuilin University of Electronic TechnologyGuilin 541004China school of Electrical and Computer Engineering Oklahoma State UniversityStillwaterOklahoma 74078USA

Topological photonics provides a platform for robust energy transport regardless of sharp corners and ***,the frequency multiplexing topological devices have attracted much attention due to the ability to separate optical signals by wavelength and hence the potential application in optical communication *** frequency multiplexing topological devices are generally based on the slow light ***,the resulting static local spatial mode or finely tuned flat band has zero-group velocity,making it difficult for both experimental excitation and channel ***,we propose and experimentally demonstrate an alternative prototype of asymmetric frequency multiplexing devices including a topological rainbow and frequency router based on floating topological edge mode(instead of localized ones);hence the multiple wavelength channels can be collectively excited with a point source and efficiently routed to separate output *** channel separation in our design is achieved by gradually tuning the band gap truncation on a topological edge band over a wide range of frequencies.A crucial feature lies in that the topological edge band is detached from bulk states and floating within the upper and lower photonic band *** interestingly,due to the sandwiched morphology of the edge band,the top and bottom band gaps will each truncate into transport channels that support topological propagation towards opposite directions,and the asymmetrical transportation is realized for the frequency multiplexing topological devices.

关键词： tuning floating hence

Microscopic mechanism of plasmon-mediated photocatalytic H_(2) splitting on Ag-Au alloy chain

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Chinese physics B 2024年第3期33卷 322-326页

作者：宋玉慧芦一瑞郭阿鑫曹逸飞李金萍付正坤严蕾张正龙 school of {1. and information Technology Shaanxi Normal UniversityXi'an 710119China

Alloy nanostructures supporting localized surface plasmon resonances has been widely used as efficient photocatalysts,but the microscopic mechanism of alloy compositions enhancing the catalytic efficiency is still *** using time-dependent density functional theory(TDDFT),we analyze the real-time reaction processes of plasmon-mediated H_(2) splitting on linear Ag-Au alloy chains when exposed to femtosecond laser *** is found that H_(2) splitting rate depends on the position and proportion of Au atoms in alloy chains,which indicates that specially designed Ag-Au alloy is more likely to induce the reaction than pure Ag ***,more electrons directly transfer from the alloy chain to the anti-bonding state of H_(2),thereby accelerating the H_(2) splitting *** results establish a theoretical foundation for comprehending the microscopic mechanism of plasmon-induced chemical reaction on the alloy nanostructures.

关键词： plasmon photocatalysis time-dependent density functional theory(TDDFT)

Tunable artificial plasmonic nanolaser with wide spectrum emission operating at room temperature

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Chinese physics B 2024年第5期33卷 466-471页

作者：周鹏郭佳琦梁琨金磊梁熊玉李俊强邓绪彦秦建宇张家森于丽 State Key Laboratory of information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory for Artificial Microstructures and Mesoscopic physics School of PhysicsPeking UniversityBeijing 100876China Peking University Yangtze Delta Institute of optoelectronics Peking UniversityNantong 226010China

With the rapid development of information and communication technology,a key objective in the field of optoelectronic integrated devices is to reduce the nano-laser size and energy *** nanolasers are unable to exceed the diffraction limit and typically exhibit low modulation rates of several *** contrast,plasmonic nanolaser utilizes highly confined surface plasmon polariton(SPP)mode that can exceed diffraction limit and their strong Purcell effect can accelerate the modulation rates to several ***,we propose a parametrically tunable artificial plasmonic nanolasers based on metal–insulator–semiconductor–insulator–metal(MISIM)structure,which demonstrates its ability to compress the mode field volume toλ/*** the pump power increases,the proposed artificial plasmonic nanolaser exhibits 20-nm-wide output ***,we investigate the effects of various cavity parameters on the nanolaser’s output threshold,offering potentials for realizing low-threshold artificial plasmonic ***,we observe a blue shift in the center wavelength of the nanolaser output with thinner gain layer thickness,predominantly attributed to the increased exciton–photon coupling *** work brings inspiration to several areas,including spaser-based interconnects,nano-LEDs,spontaneous emission control,miniaturization of photon condensates,eigenmode engineering of plasmonic nanolasers,and optimal design driven by artificial intelligence(AI).

关键词： surface plasmon polaritons nanolaser ultrafast MISIM

Interfacial DMI in Fe/Pt thin films grown on different buffer layers

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Chinese physics B 2024年第4期33卷 712-718页

作者：张文君魏菲刘冰周阳康仕寿孙兵 school of {1. and Electronic information Weifang UniversityWeifang 261061China school of {1. and State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

We study the interfacial Dzyaloshinskii-Moriya interactions(i-DMI)of Fe/Pt bilayers grown on Si substrates with MgO,SiO_(2),or Ta each as a buffer layer on the basis of wave-vector-resolved Brillouin light scattering(BLS)*** obtained i-DMI energy values for Fe/Pt on MgO,Ta,and SiO_(2) buffer layers are 0.359,0.321.and 0.274 mJ/m~2,*** large i-DMI value observed in Fe/Pt system on the MgO buffer layer can be attributed to the good interfacial quality and the Rshaba effect at the MgO/Fe ***,the MgO/Fe/Pt system,benefiting from better sample quality,exhibits a lower damping ***,layer-resolved first-principles calculations are carried out to gain a more in-depth understanding of the origin of the i-DMI in the Fe/Pt *** results indicate that in the Fe(1.0)/Pt(1.1.system,the substantial DMI energy between Fe spins at the interface is related to a significant change in spin-orbit coupling(SOC)energy in the neighboring Pt *** contrast,for the MgO(002)/Fe(002)system,both the DMI and its related SOC energy are concentrated at the interfacial Fe *** investigation will provide a valuable insight into the spintronic community in exploring novel devices with chirality dependence.

关键词： Fe/Pt i-DMI BLS ferromagnetic resonance magnetic relaxation