期刊：
Journal of Lightwave Technology,2025年43(7):3506-3512 ISSN：0733-8724
作者机构：
["Zhou, Miaofang; Cao, Guangtao; Zhang, Ling; Liu, Junyu; Guan, Yuhong"] College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha, China;[Zhou, Xinshun] Hubei university of technology engineering and technology college, Wuhan, China
摘要：
We propose a holes-assisted few-mode fiber (HFMF) consisting of a GeO2 doped SiO2 core, a SiO2 cladding, and three strategically positioned holes. The incorporation of these holes produces a significant contribution in separating the non-degenerated linearly polarized (LP) modes and degenerated spatial modes, thereby considerably improving the mode spacing. Numerical simulation results demonstrate that our designed HFMF can support 12 spatial modes with the min effective index difference between adjacent non-degenerated LP modes (Δneff) larger than 1.65 × 10−3 and the min effective index difference between adjacent degenerated spatial modes (δneff) above 2.64 × 10−4 at the wavelength of 1550 nm, breaking through the trade-off between mode spacing and the number of modes. Furthermore, the min Δneff and min δneff of exceeding 1.63 × 10−3 and 2.44 × 10−4 can be achieved over the whole C and L bands, respectively. The new designed fiber is specifically tailored for less MIMO mode division multiplexing (MDM), enabling significant capacity enhancement in optical communication systems.
摘要：
Enhancing light–matter interactions is particularly important in the field of micronano optics, which can be achieved through plasmon-induced transparency. A new type of metasurface consisting of a single layer of graphene is mainly investigated in the study. This structure is mainly composed of a graphene strip and two graphene blocks, generating plasmon-induced transparency at terahertz frequencies via weak coupling between the two bright modes. Furthermore, the time-domain finite-difference method (FDTD) and coupled-mode theory (CMT) are utilized to further explore the physical mechanism of PIT formation. By adjusting the Fermi level of graphene, the transmittance window of PIT can be effectively regulated, resulting in a reflectivity of more than 65% for this structure. Moreover, the influence of the graphene Fermi level on the slow-light effect was analyzed, and the group index was increased from 450 to 562 when the Fermi level of graphene was increased from 0.8 eV to 1.1 eV. The findings are important for the realization of multifunctional terahertz devices such as modulators and slow light.
关键词：
quartz flexible accelerometer;heat transfer simulation model;unsteady heat conduction;temperature field
摘要：
Quartz flexible accelerometers (QFAs) are a type of temperature-sensitive sensor, whereby a change in temperature will cause the key parameters of the accelerometer to drift and cause stability errors. Due to the absence of effective methods for sensing the temperature of internal accelerometer components, existing temperature error correction approaches primarily rely on shell temperature measurements to establish correction models. Consequently, most correction methods achieve higher accuracy during the steady-state heat conduction phase of the accelerometer, whereas the correction error markedly increases during the transient heat conduction phase. To elucidate the temperature discrepancy between the QFA shell and its internal components and to support the development of a temperature error correction method for QFAs based on the internal temperature as a reference, this paper investigated the heat exchange dynamics between the interior and exterior of a QFA. A thermal conduction simulation model of the QFA was established, from which the spatiotemporal distribution patterns of the internal temperature field were derived. The results indicate that the temperature of the QFA shell changes significantly faster than that of the internal meter head in the early stage of the temperature change. The temperature gradient between the shell and the meter head first increases and then decreases, and the rate of temperature change in the upper part of the accelerometer is faster than that in the lower part. Before thermal equilibrium is reached, the temperature distribution inside the accelerometer is uneven in terms of time and space. Inside the accelerometer, the yoke iron, swing plate assembly, servo circuit, and magnetic steel assembly are the main components that exhibit differences in the internal temperature change in the QFA. When developing the temperature error correction method, it was crucial to address and mitigate the impact of temperature variations among these components. The average RMSE between the predicted temperature from the heat transfer model established in this paper and the experimental results was 0.4 °C. This indicates that the model can accurately predict the temperature variation within the QFA, thereby providing robust support for investigating the temperature behavior inside the QFA and offering essential technical foundations for enhancing the accuracy of the temperature error correction method.
摘要：
Magnetic anisotropy (MA) is one of the key properties in two-dimensional (2D) magnetic materials, as it determines the type of magnetism and its stabilities. Since the discovery of intrinsic 2D magnetic materials, the MA has garnered significant attention, and more efforts have been devoted to its effective manipulation. In this study, we construct van der Waals heterostructures by overlaying the CrI3 monolayer on five kinds of MXene layers. Our first-principles calculations reveal that the MA of the CrI3 layer can be effectively tuned through the formation of CrI3/MXene heterostructures. Notably, the magnetic anisotropy energy (MAE) can be enhanced by up to 71% in CrI3/Ti2CO2. Furthermore, by applying biaxial strain to CrI3/MXene, we achieve a wide-range regulation of MAE, and even small strain can induce a switch in the spin direction between in-plane and out-of-plane orientations. This pronounced response of MAE to strain should be attributed to the tunable interfacial effects. Our findings provide enlightenment to manipulate the MAE of 2D magnetic materials effectively through the synergistic effect of interfacial effects and strain. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).
摘要：
Non-Abelian multiband topology, characterized by frame charges, has garnered significant attention in the past few years. The non-Abelian frame charge evolution can be deduced from the rotation of the multiband in momentum space, which can promise potential applications based on the dynamic non-Abelian topological effects. In this work, based on two-dimensional phononic crystals, we directly observe the eigenstate frame rotation to verify non-Abelian band topology, which further predicts the location of the corner modes in this multigap system. These one-dimensional edge states of band gaps or bulk band continuum that induce zero-dimensional corner states are also confirmed experimentally. The corresponding higher-order topology is examined by detecting the acoustic responses in a finite phononic crystal sample. Our work provides experimental evidence for the unique non-Abelian band topology and a convenient platform for studying novel higher-order topological matter phases.
摘要：
Topological boundary state is the hallmark feature of topological physics. Recently, non-Hermicity was found to dramatically expand the scope of topological physics, and provides an exotic strategy to manipulate the topological boundary states. Here, we realize the non-Hermitian winding and braiding of topological edge states in electric circuits. The topological edge states originate from the nontrivial bulk polarization. The twisted winding of a topological edge band and the ensuing bipolar hybrid skin-topological effect, and the Hopf link and Solomon link braidings between two topological edge bands, are visualized by measuring the admittances in circuit experiments. Our findings deepen the insight into the interaction between the Hermitian and non-Hermitian topologies, and inspire a mechanism in topological boundary wave manipulation.
期刊：
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY,2025年88:102791 ISSN：0364-5916
通讯作者：
Du, Y;Fabrichnaya, O
作者机构：
[Du, Yong; Yang, Lianfeng; Liu, Yuling] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Zeng, Yinping] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Fabrichnaya, Olga] TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.;[Zhang, Ligang] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.
通讯机构：
[Du, Y ] C;[Fabrichnaya, O ] T;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.
关键词：
Phase diagram;Two-sublattice partially ionic liquid model;CALPHAD;The Na2O-SiO2 system
摘要：
Thermodynamic investigation of the Na 2 O-SiO 2 system is extremely significant for the silicate glass industry and the control of Na 2 O balance in the input materials of blast furnaces. The Na 2 O-SiO 2 system has been thermodynamically assessed numerous times in the previous studies. However, the phase equilibria in the Na 2 O-rich side remain inadequately described. Consequently, the Na 2 O-SiO 2 system was reassessed by the CALPHAD approach in the present work. The liquid phase was described by using the two-sublattice partially ionic liquid model (Na +1 ) P (O −2 ,SiO 4 −4 ,SiO 2 ) Q and six intermediate compounds were treated as stoichiometric compounds due to their limited solid solubilities. A set of self-consistent thermodynamic parameters was then obtained, and the experimental phase diagram data and thermodynamic properties can be satisfactorily reproduced by the calculation within the experimental errors. The present thermodynamic parameters contribute to the composition design of silicate glass and the formulation of input materials in blast furnaces.
Thermodynamic investigation of the Na 2 O-SiO 2 system is extremely significant for the silicate glass industry and the control of Na 2 O balance in the input materials of blast furnaces. The Na 2 O-SiO 2 system has been thermodynamically assessed numerous times in the previous studies. However, the phase equilibria in the Na 2 O-rich side remain inadequately described. Consequently, the Na 2 O-SiO 2 system was reassessed by the CALPHAD approach in the present work. The liquid phase was described by using the two-sublattice partially ionic liquid model (Na +1 ) P (O −2 ,SiO 4 −4 ,SiO 2 ) Q and six intermediate compounds were treated as stoichiometric compounds due to their limited solid solubilities. A set of self-consistent thermodynamic parameters was then obtained, and the experimental phase diagram data and thermodynamic properties can be satisfactorily reproduced by the calculation within the experimental errors. The present thermodynamic parameters contribute to the composition design of silicate glass and the formulation of input materials in blast furnaces.
期刊：
Micro and Nanostructures,2025年:208218 ISSN：2773-0123
通讯作者：
Lijuan Wu
作者机构：
[Lijuan Wu; Jiahong He; Zhipeng Shen; Gengbin Zhu; Qiqi Tang; Zongyang Yi; Guanglin Yang; Deqiang Yang] School of Physics and Electronic Science, Changsha University of Science and Technology, Yuntang Campus, 410114 Changsha, China
通讯机构：
[Lijuan Wu] S;School of Physics and Electronic Science, Changsha University of Science and Technology, Yuntang Campus, 410114 Changsha, China
摘要：
A 1200V 4H-SiC lateral double-diffused MOSFETs (LDMOS) with embedded auto-adjust JFET (AD-JEFT) and double-reduced surface fields technology is proposed. The AD-JEFT, as the conduction path of electrons from N+ source to the P-well channel, is embedded in P+ well. In the on-state, as the device is pressurized, the increase of depletion charge will reduce the effective channel width of AD-JFET. As a result, the potential barrier of the AD-JFET channel will increase rapidly, making it difficult for electrons to transfer and resulting in a reduction of the saturation current. Compared with the common LDMOS (C-LDMOS), the saturation current ( I dsat ) of the proposed LDMOS with AD-JEFT (ADJ-LDMOS) is reduced by 53.3%. Meanwhile, the short circuit capability is improved by 110.5%. In addition, the top P-type region of ADJ-LDMOS is divided into a higher doped P-top region and a lower doped P-top2 region, which greatly improves the blocking ability. The breakdown voltage was increased by 21.9% without increasing the specific on-resistance ( R on,sp ).
A 1200V 4H-SiC lateral double-diffused MOSFETs (LDMOS) with embedded auto-adjust JFET (AD-JEFT) and double-reduced surface fields technology is proposed. The AD-JEFT, as the conduction path of electrons from N+ source to the P-well channel, is embedded in P+ well. In the on-state, as the device is pressurized, the increase of depletion charge will reduce the effective channel width of AD-JFET. As a result, the potential barrier of the AD-JFET channel will increase rapidly, making it difficult for electrons to transfer and resulting in a reduction of the saturation current. Compared with the common LDMOS (C-LDMOS), the saturation current ( I dsat ) of the proposed LDMOS with AD-JEFT (ADJ-LDMOS) is reduced by 53.3%. Meanwhile, the short circuit capability is improved by 110.5%. In addition, the top P-type region of ADJ-LDMOS is divided into a higher doped P-top region and a lower doped P-top2 region, which greatly improves the blocking ability. The breakdown voltage was increased by 21.9% without increasing the specific on-resistance ( R on,sp ).
摘要：
Two-dimensional (2D) second-order topological insulators (SOTIs) with corner states have recently attracted significant interest. It is fascinating to explore the coupling of corner states with additional degrees of freedom. Here, we propose that layer-polarized corner states can be induced by a perpendicular electric field in the AAstacking bilayer 2D SOTIs. Our result reveals that the transition between non-layer-polarized and layer-polarized corner states depends on the interlayer exchange symmetry, which can be controlled by the perpendicular electric field. This finding is further verified in two types of SOTIs: bilayer modified Kane-Mele model and Cn-symmetric SOTIs. In contrast to the bilayer modified Kane-Mele model, magnetic Cn-symmetric SOTIs are predicted to exhibit corner states that are not only layer polarized but also additionally spin-polarized, as exemplified by 1T-NiCl2. Based on the first-principles calculations and tight-binding (TB) model, we predict that ferromagnetic (FM) single-layer 1T-NiCl2 exhibits C3-symmetric corner states with nontrivial fractional charge in both spin channels. Notably, in the bilayer NiCl2 with antiferromagnetic (AFM) ground state, applying a perpendicular electric field drives the transition of the corner states from a spin- and layer-degenerate state to a spin- and layer-polarized state. Reversing the electric field direction simultaneously switches both the spin and layer polarizations. Finally, layer-polarized corner states are also confirmed in the nonmagnetic bilayer hexagonal SOTI. These results indicate that electrically tunable layer-polarized corner states could be realized in a variety of bilayer SOTIs and interlayer magnetic configurations. Our work offers a strategy for designing layer-polarized corner states in 2D SOTIs, which could enhance their potential applications in topological electronic devices.
作者：
Lam, Leo S. I.;Deng, Hai-Yao;Zhang, Wei-Bing;Nwankwo, Udoka;Xiao, Chu;...
期刊：
Physical Review E,2025年111(4) ISSN：2470-0045
通讯作者：
Ruan, HH;Lee, CS;Lam, CH
作者机构：
[Ruan, Haihui; Nwankwo, Udoka; Lam, Leo S. I.] Hong Kong Polytech Univ, Dept Mech Engn, Hong Kong, Peoples R China.;[Deng, Hai-Yao] Cardiff Univ, Sch Phys & Astron, 5 Parade, Cardiff CF24 3AA, Wales.;[Zhang, Wei-Bing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Peoples R China.;[Lee, Chun-Shing; Lee, CS; Yip, Cho-Tung; Xiao, Chu] Harbin Inst Technol, Dept Phys, Shenzhen 518055, Peoples R China.;[Lam, Chi-Hang; Lam, CH] Hong Kong Polytech Univ, Dept Appl Phys, Hong Kong, Peoples R China.
通讯机构：
[Lee, CS ; Ruan, HH ; Lam, CH ] H;Hong Kong Polytech Univ, Dept Mech Engn, Hong Kong, Peoples R China.;Harbin Inst Technol, Dept Phys, Shenzhen 518055, Peoples R China.;Hong Kong Polytech Univ, Dept Appl Phys, Hong Kong, Peoples R China.
摘要：
The physics of glass has been a significant topic of interest for decades. Dynamical facilitation is widely believed to be an important characteristic of glassy dynamics, but the precise mechanism is still under debate. We propose a lattice model of glass called the facilitated random walk (FRW). Each particle performs a continuous time random walk in the presence of its own random local kinetic constraints. The particles do not interact energetically. Instead, they interact kinetically with a hopping rate resampling rule under which motions of a particle can randomly perturb the local kinetic constraints of other particles. This dynamic interaction is reversible, following a rate restoration rule. A step-by-step reversal of the particle motions exactly restores the previous constraints, modeling randomness quenched in the configuration space of glass. The model exhibits stretched exponential relaxation and dynamical heterogeneity typical of glasses. Despite the lack of an explicit facilitation rule, the FRW shows facilitation behaviors closely analogous to those of the kinetically constrained models (KCM). The FRW is a coarse-grained version of the distinguishable particle lattice model (DPLM) and this exemplifies that compatible defect and atomistic models can complement each other in the study of glass.
期刊：
OPTICS AND LASER TECHNOLOGY,2025年180:111555 ISSN：0030-3992
通讯作者：
Guangtao Cao<&wdkj&>Hui Yang
作者机构：
[Peng, Meiyu; Yang, Hui] School of Physics and Electronics, Hunan Normal University, Changsha 410081, China;Key Laboratory of Physics and Devices in Post-Moore Era, College of Hunan Province, Changsha 410081, China;[Cao, Guangtao; Li, Yanbei; Liu, Hui] School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410004, China;[He, Hairong] School of Physics and Electronics, Hunan Normal University, Changsha 410081, China<&wdkj&>Key Laboratory of Physics and Devices in Post-Moore Era, College of Hunan Province, Changsha 410081, China
通讯机构：
[Guangtao Cao; Hui Yang] S;School of Physics and Electronics, Hunan Normal University, Changsha 410081, China<&wdkj&>School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410004, China
摘要：
Metasurface-enabled holography holds vital applications in various fields such as optical display, optical data storage, and optical encryption. Despite the rapid development of multiplexed metaholograms through exploiting different physical dimensions of photons such as polarization, amplitude, wavelength, and angular momentum, the multiplexing channel is approaching its limit due to the almost exhausted existing physical dimensions of photons. Here we demonstrate the higher-order Poincaré sphere (HOPS)-multiplexed holography by exploiting vector beam on the HOPS as a new physical dimension for holographic multiplexing. The underlying mechanism relies on independent control of phase shifts in two spin eigenstates to modulate the vector beam induced fields. As proof of concept, we demonstrate a meta-hologram with four multiplexing channels that exhibit independent holographic images when the incident beams are on the −2nd order, −1st order, 1st order and 2nd order HOPS, respectively. Moreover, leveraging the unique characteristic of HOPS-multiplexed holography, high-security optical anti-counterfeiting and information encryption have been demonstrated as well. Our work harnesses the previously inaccessible vector beams as independent information carries for holographic multiplexing, promising to potential applications in optical display and optical encryption.
Metasurface-enabled holography holds vital applications in various fields such as optical display, optical data storage, and optical encryption. Despite the rapid development of multiplexed metaholograms through exploiting different physical dimensions of photons such as polarization, amplitude, wavelength, and angular momentum, the multiplexing channel is approaching its limit due to the almost exhausted existing physical dimensions of photons. Here we demonstrate the higher-order Poincaré sphere (HOPS)-multiplexed holography by exploiting vector beam on the HOPS as a new physical dimension for holographic multiplexing. The underlying mechanism relies on independent control of phase shifts in two spin eigenstates to modulate the vector beam induced fields. As proof of concept, we demonstrate a meta-hologram with four multiplexing channels that exhibit independent holographic images when the incident beams are on the −2nd order, −1st order, 1st order and 2nd order HOPS, respectively. Moreover, leveraging the unique characteristic of HOPS-multiplexed holography, high-security optical anti-counterfeiting and information encryption have been demonstrated as well. Our work harnesses the previously inaccessible vector beams as independent information carries for holographic multiplexing, promising to potential applications in optical display and optical encryption.
期刊：
Journal of the American Ceramic Society,2025年:e20565 ISSN：0002-7820
通讯作者：
Du, Y;Fabrichnaya, O
作者机构：
[Du, Yong; Yang, Lianfeng; Liu, Yuling] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Zeng, Yinping] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Peoples R China.;[Fabrichnaya, Olga] TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.;[Zhang, Ligang] Cent South Univ, Sch Mat Sci & Engn, Changsha, Peoples R China.
通讯机构：
[Du, Y ] C;[Fabrichnaya, O ] T;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.
摘要：
The Na2O & horbar;CaO & horbar;SiO2 ternary system, which is a very complex pseudo-ternary system, is a fundamental system widely used as glasses and glass-ceramics. Its thermodynamic description is crucial for understanding solidification and subsequent heat treatments. In this work, a thermodynamic assessment of the Na2O & horbar;CaO & horbar;SiO2 system was conducted by applying the CALPHAD method. The liquid phase in the Na2O & horbar;CaO & horbar;SiO2 system was successfully described by the two-sublattice partially ionic liquid model (Na+1,Ca+2)(P)(O-2,SiO4-4,SiO2)(Q) and two new sublattice models of (Na+1,Ca+2)(2)(Na+1,Va)(1)(Si+4)(1)(O-2)(4) and (Na+1,Ca+2)(2)(M1)(Va,Na+1)(3)(M2)(Ca+2,Na+1)(3)(M3)(Ca+2)(1)(M4)(Si+4)(6)(O-2)(18) with accurate cation distributions in their sublattices were developed to respectively describe the ternary solid solution phases beta N1C1S1 and Combeite in this work. The other ternary compounds were treated as stoichiometric ones due to their limited solid solubilities. Based on the reliable experimental data, a set of self-consistent thermodynamic parameters was obtained. The calculated isothermal sections, vertical sections, liquidus projection, and thermodynamic properties can satisfactorily reproduce the experimental data within the experimental errors. In addition, the present thermodynamic description contributes to the reliable prediction for the melting temperatures and primary crystallization phases for the Na2O & horbar;CaO & horbar;SiO2 glasses, providing valuable insights for the design of glass and glass-ceramics compositions and heat treatment processes.
通讯机构：
[Shu, CC ] C;Cent South Univ, Sch Phys, Hunan Key Lab Nanophoton & Devices, Hunan Key Lab Supermicrostruct & Ultrafast Proc, Changsha 410083, Peoples R China.
摘要：
We theoretically explore the precise control of a molecular polariton by strongly coupling the lowest three rotational states of a single molecule with a single-mode cavity. We examine two distinct cavity resonance configurations: a fundamental frequency cavity (wc = 2B with the rotational constant B) resonating with the lowest two rotational states, and a second harmonic cavity (wc = 4B) coupling with the first and second excited rotational states. We propose two control schemes based on the two polariton configurations and derive the corresponding pulse-area theorems to achieve a theoretical maximum orientation of 0.7746, identical to the molecule without the cavity. The control schemes are analyzed in carbonyl sulfide (OCS) molecules in their ground rotational state. Our numerical simulation results demonstrate the theoretical control schemes and analyze the sensitivity of the molecular polariton orientation degree to the control field bandwidth and phases. This work provides a valuable reference for achieving maximum field-free orientation of ultracold three-state molecules in a cavity using analytically designed pulses.
摘要：
Deep learning-based dMRI super-resolution methods can effectively enhance image resolution by leveraging the learning capabilities of neural networks on large datasets. However, these methods tend to learn a fixed scale mapping between low-resolution (LR) and high-resolution (HR) images, overlooking the need for radiologists to scale the images at arbitrary resolutions. Moreover, the pixel-wise loss in the image domain tends to generate over-smoothed results, losing fine textures and edge information. To address these issues, we propose a novel continuous super-resolution method for dMRI, called CSR-dMRI, which utilizes an anatomical structure-assisted implicit neural representation learning approach. Specifically, the CSR-dMRI model consists of two components. The first is the latent feature extractor, which primarily extracts latent space feature maps from LR dMRI and anatomical images while learning structural prior information from the anatomical images. The second is the implicit function network, which utilizes voxel coordinates and latent feature vectors to generate voxel intensities at corresponding positions. Additionally, a frequency-domain-based loss is introduced to preserve the structural and texture information, further enhancing the image quality. Extensive experiments on the publicly available HCP dataset validate the effectiveness of our approach. Furthermore, our method demonstrates superior generalization capability and can be applied to arbitrary-scale super-resolution, including non-integer scale factors, expanding its applicability beyond conventional approaches.
摘要：
Covalent organic frameworks (COFs) exhibit considerable potential in gas separations owing to their remarkable stability and tunable pore structures. Nevertheless, their application as gas separation membranes is hindered by limited size-sieving capabilities and poor processability. In this study, we propose a novel molecular weaving strategy that combines hydroxyl polymers and 2D TpPa−SO 3 H COF nanosheets, achieving high gas separation efficiency. Driven by the strong electrostatic interactions, the hydroxyl chains thread through the COF pores, effectively weaving and assembling the composites to achieve exceptional flexibility and high mechanical strength. The penetrated chains also reduce the effective pore size of COFs, and combined with the “secondary confinement effect” stemming from abundant CO 2 sorption sites in the channels, the PVA@TpPa−SO 3 H membrane demonstrates a remarkable H 2 permeance of 1267.3 GPU and an H 2 /CO 2 selectivity of 43, surpassing the 2008 Robson upper bound limit. This facile strategy holds promise for the manufacture of large-area COF-based membranes for small-sized gas separations.
摘要：
Silicon-based metasurfaces exhibit significant potential for manipulating optical wavefronts across the visible and infrared wavelength ranges due to their compact size and compatibility with CMOS technology. However, previous research has predominantly focused on developing either monofunctional devices or switchable bifunctional devices. In this work, we propose a silicon-based bifunctional metasurface that demonstrates polarization-selective anomalous transmission and Airy beam shaping within the visible spectrum. The metasurface is composed of an array of 80 × 201 rectangular dielectric silicon elements deposited on a silicon dioxide substrate. We thoroughly analyze the relationship between phase shift and geometric dimensions to enable the successful design of the target metasurface. By carefully selecting the periodicity and geometry of the unit cell, we achieve anomalous transmission and Airy beam shaping for two orthogonal linear polarization states of normally incident light at a wavelength of 632.8 nm. Additionally, we also demonstrate a polarization-multiplexed function for anomalous transmission and autofocusing Airy beam using a similar concept. Our approach presents a novel paradigm for designing multifunctional optical devices that operate in the visible spectrum.
Silicon-based metasurfaces exhibit significant potential for manipulating optical wavefronts across the visible and infrared wavelength ranges due to their compact size and compatibility with CMOS technology. However, previous research has predominantly focused on developing either monofunctional devices or switchable bifunctional devices. In this work, we propose a silicon-based bifunctional metasurface that demonstrates polarization-selective anomalous transmission and Airy beam shaping within the visible spectrum. The metasurface is composed of an array of 80 × 201 rectangular dielectric silicon elements deposited on a silicon dioxide substrate. We thoroughly analyze the relationship between phase shift and geometric dimensions to enable the successful design of the target metasurface. By carefully selecting the periodicity and geometry of the unit cell, we achieve anomalous transmission and Airy beam shaping for two orthogonal linear polarization states of normally incident light at a wavelength of 632.8 nm. Additionally, we also demonstrate a polarization-multiplexed function for anomalous transmission and autofocusing Airy beam using a similar concept. Our approach presents a novel paradigm for designing multifunctional optical devices that operate in the visible spectrum.
摘要：
Wearable thermoelectric generators (WTEGs) are of significance in the conversion of body heat into electricity for the purpose of powering wearable electronic devices. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) exhibit exceptional thermoelectric power factors and mechanical stability, making them promising flexible thermoelectric materials. However, the output voltage of the present TMDC-based WTEGs remains at a relatively low level. In this study, we precisely modulate the electronic structure of titanium disulfide (TiS 2 ) nanosheets in a restacked film by surface modification, leading to the decoupling phenomenon of a simultaneous rise in the electrical conductivity and the Seebeck coefficient. This method enhances the thermoelectric power factor by approximately 14 times compared to pre-modified samples. We fabricated a flexible self-reassembly WTEG using 1T-phase molybdenum disulfide (MoS 2 ) nanosheets as p -type material and modified TiS 2 nanosheets as an n -type material. The generator achieved a voltage output of approximately 15 mV while harvesting heat from the human arm, showcasing its potential for practical applications.
摘要：
Skin effects, the phenomena of the bulk states collapsing toward open boundaries, have mostly been revealed in non-Hermitian systems hosting nonreciprocity. Either the first-order or the higher-order of skin effects have been observed. Here, we report our first discovery of a hybrid-order of skin effects, of which the utilized two-dimensional system exhibits not only the first-order skin modes, but also the second-order skin modes respectively on the edges and the corners, the different type of open boundaries. We propose a universal approach to achieving nonreciprocal couplings by virtue of the loss and bilayer degree of freedom, as the critical role it plays. Our models are implemented in square- and diamond-shaped phononic crystals, and the hybrid order of acoustic skin modes is evidenced in experiment. Our Letter may foster the development of non-Hermitian physics.
期刊：
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS,2025年23(5):e2025SW004336 ISSN：1542-7390
通讯作者：
Zou, ZM
作者机构：
[Li, Qinzeng; Xu, Jiyao; Zou, Ziming; Zhong, Jia; Zou, ZM; Lu, Yang; Sun, Longchang; Yuan, Wei] Chinese Acad Sci, Natl Space Sci Ctr, Beijing, Peoples R China.;[Zhong, Jia] Univ Chinese Acad Sci, Beijing, Peoples R China.;[Zou, Ziming; Zhong, Jia; Zou, ZM; Lu, Yang] Natl Space Sci Data Ctr, Beijing, Peoples R China.;[Wu, Kun] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Peoples R China.
通讯机构：
[Zou, ZM ] C;Chinese Acad Sci, Natl Space Sci Ctr, Beijing, Peoples R China.;Natl Space Sci Data Ctr, Beijing, Peoples R China.
摘要：
We developed a deep convolutional neural network-based program code that automatically detects equatorial plasma bubbles (EPBs), segments EPB morphologies, and then extracts their features (including EPBs' northernmost foot latitudes and zonal drift velocities) from OI 630 nm airglow images. From 2012 to 2022, all-sky airglow images from Qujing Station, China (geographic: 25°N, 104°E; geomagnetic: 15.1°N, 176.7°E), were manually labeled as EPBs or non-EPBs. Some images showing typical EPB morphologies also had their contours annotated. This created two unique data sets which are both suitable for supervised learning models. Based on the above data sets, numerous experiments were conducted to train the EPB recognition model (EPB-RM) and the EPB morphology segmentation model (EPB-MSM). The results on the test set indicate that ResNet18+CBAM model can perform the best in recognizing EPB (precision: 99%, recall: 91%), and all models perform better during geomagnetically quiet periods and high solar activity periods (F10.7 value >140) than during geomagnetically disturbed periods (Dst index ≤ −30 nT or Kp index ≥3) and low solar activity periods. The EPB-MSM based on Deeplabv3plus had the highest accuracy (88.2%) for extracting the EPB morphology. Statistical features extracted using the EPB feature extraction program (EPB-FEP) were highly consistent with those extracted manually. The test results verified that machine learning is an excellent method for automatically detecting and extracting EPB characteristics. Our study provides a convenient tool for analyzing massive EPB images.
Machine learning identified equatorial plasma bubbles (EPBs) and extracted their morphologies, velocities, and northernmost points from the airglow images
The precision of the model in identifying EPBs under different solar and geomagnetic conditions reached 99%
Two new image sets of EPBs were established for EPB research and the training of machine learning models
Equatorial plasma bubbles (EPBs) usually form in the F2 region of the ionosphere after sunset and cause rapid fluctuations in the amplitudes and phases of radio signals. Previous analyses used manual methods to identify EPBs and extract their evolutionary characteristics. However, these methods are inefficient and tedious for large data sets. Our research aims to develop an intelligent EPB detection and feature extraction (the northernmost point latitude and zonal drift velocity) method with high accuracy based on machine learning. Based on 723,375 OI 630 nm airglow images from 2012 to 2022 at Qujing station in China (geographical coordinates: 25°N, 104°E), we manually classified these images as EPB or non-EPB and annotated their image contours exhibiting typical EPB morphologies. On this basis, EPB recognition and morphology segmentation models were trained, and an automatic extraction program for EPB features was constructed. The test results verified that machine learning is an excellent method for automatically detecting and extracting EPB characteristics. Our study provides a convenient tool for analyzing massive EPB images.
摘要：
Change detection using deep learning methods in optical remote sensing imageries has become the mainstream method, primarily due to their strong spatial-temporal transferability. However, current change detection models are designed for high-quality optical remote sensing imageries and seldom account for image conditions such as haze cover or low-light scenarios. As we know, the quality of optical remote sensing imageries can be severely degraded by haze or low-light conditions, which in turn significantly impairs the performance of change detection models. Yet there is still a lack of advanced change detection models designed for the aforementioned adverse scenarios at present. To address this gap, we proposed a simple image-adaptive change detection model named IA-CDNet, aimed at improving model performance in adverse image conditions. Initially, we developed an image-adaptive filter module, which employed several differentiable image filter operators to enhance the quality of the inputted image. Notably, the parameters of these filters are automatically learned using a lightweight convolution neural network (CNN) module. Then, a generic change detection model is integrated to extract low-level and high-level semantic information, facilitating the detection of changes between bi-temporal remote sensing imagery. Ultimately, experiments conducted on three open-sourced change detection datasets and two large-scale real-world scenarios have demonstrated the effectiveness of IA-CDNet. We anticipate this model can make an important contribution to change detection research fields and improve model performance further. The Open sourced code can be accessed at: https://github.com/wzp8023391/Change-detection-in-adverse-conditions.
