通讯机构:
[Xiaohui Ling] L;[Lei Zhou] S;Laboratory for Spin-Orbit Photonics, College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, 421002 China<&wdkj&>State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Physics Department, Fudan University, Shanghai, 200433 China<&wdkj&>State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Physics Department, Fudan University, Shanghai, 200433 China
摘要:
The photonic spin‐Hall effect (PSHE) at generic interfaces is dictated by two geometric phases with different origins, namely the spin‐redirection‐Berry and Pancharatnam–Berry phases. The Pancharatnam–Berry phase plays an important role in the PSHE, while it is generally believed that the PSHE at interfaces is solely caused by the spin‐redirection‐Berry phase. Abstract Although the photonic spin‐Hall effect (PSHE) at optical interfaces has been widely studied in past years, its physical origin remains obscure. Here, through studying the scatterings of circularly polarized beams obliquely incident on a series of junctions linking two homogenous optical media, how the physical origin of the PSHE evolves as the interface changes from a slowly varying junction to a step‐like sharp one is explored. Beams transmitted through a generic interface consist of two modes, a spin‐maintained normal mode carrying a spin‐redirection Berry (SRB) phase and a spin‐flipped abnormal mode exhibiting a Pancharatnam–Berry (PB) phase. Under linear‐polarization incidence, a spin‐polarized beam transmitted through each junction is generally an interference of normal and abnormal modes corresponding to two different incident circular polarizations, and thus the resulting PSHE is dictated by the interplay and competition between two effects dictated by SRB and PB phases, respectively. Shrinking the interfacial region can increase the strength of the abnormal mode, making the measured PSHE change from the SRB‐dominated one to the PB‐dominated one. The results establish a unified framework to understand the PSHE at generic interfaces, offering practical ways to control the PSHE by “designing” the abnormal scatterings on optical interfaces.
摘要:
Recently, there has been renewed interest in the combination of deep learning and side-channel analysis (SCA). Many previous studies have transformed the traditional SCA into a classification problem in deep learning. This paper considers it as a regression problem based on the principle that the changes of some circuit states are related to the special operation in cipher. We proposed a regression model which consists of an initial layer, a deep feature mining dense layer, and a regression layer. In the term of dataset, there are two sources of data: the raw ASCAD power traces and the data sampled from FPGA implementation of AES and PRESENT. The mainly advantages of this model and regression task processing method is that it can adapt to different cryptographic algorithms on the same hardware device. Moreover, the experimental result that the model can significantly improve the attack accuracy of SCA. In ASCAD, its prediction accuracy achieves 2.90% and 3.63% for two different intermediate values, and their correlation coefficient evaluation 0.873, 0.840. In FPGA power dataset, their prediction and correlation coefficient are 3%, 4%, and 0.963, 0.987 respectively.
关键词:
Berry phase;First order optics;Gaussian beams;Light beams;Light fields;Vortex beams
摘要:
We employ a full-wave theory to systematically investigate two types of spin-orbit interactions and their topological phase transitions for various light beams (e.g., Laguer re Gaussian, Bessel, and Bessel-Gaussian beams) at optical interfaces, and explore the influence of beam parameters on the spin-Hall shift. It is demonstrated that at small-angle incidence, the beam profile and spin-Hall shift are significantly affected by the beam parameters (e.g., waist radius, radial index, azimuthal index, and cone angle), whereas at large-angle incidence, only the azimuthal index has a salient influence on them. We further find that the Bessel beam and the Gaussian-modulated ones (i.e., Laguer re-Gaussian and Bessel-Gaussian beams) have similar topological phase transition phenomena but different shifts. Quantitative dependences of beam parameters, such as waist radius, radial index, azimuthal index, and cone angle, on the shift are also presented. Our findings offer alternative degrees of freedom in controlling the topological phase transitions of light, and suggest a valuable insight for exploring the applications of SOIs of diverse light fields.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
摘要:
We investigate the nonlinear evolutions of modulation instability (MI) under the interaction of Kerr nonlinearity with pure higher, even-order dispersion (HEOD) by using the truncating method of three-wave mixing. For any HEOD, we find the phase-plane topological structure of the MI changes in three frequency regions whose ranges depend on the order of HEOD. And we present the novel types of nonlinear evolutions of the MI, which do not exist in the case of quadratic dispersion. Taking the pure-sextic dispersion as an example, the theoretical predictions of the MI evolutions are confirmed by numerically solving the modified nonlinear Schrodinger equation. Our results not only further deepen the understanding of MI, but also provide a universal guideline for experimental investigation of nonlinear waves, such as breather solitons or rogue waves excitation, in nonlinear Kerr media with pure HEOD. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
通讯机构:
[Tan, YL ] H;Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421008, Hunan, Peoples R China.
关键词:
Radon monitor;Rn-222;Rn-220;CR-39;Collection efficiency;The effect of humidity;Electrostatic collection method
摘要:
Based on electrostatic collection and CR-39, a novel radon monitor (Hynu EIRM-II) was designed to reduce the effect of humidity for simultaneous measurement of Rn-222 and Rn-220 with two 50 mL hemispherical internal cells connected in a serial configuration. A 10 cm tube connects two internal cells to avoid entry of Rn-220 into the second one. While the relative humidity in the internal cell of Hynu EIRM-II is 1% or above 10%, the difference of Po-216 collection efficiency estimated by an improved model is 8.36% at a cell-wall voltage of 2000 V. The simultaneous measurement experiments of Rn-222 and Rn-220 concentrations were performed under three relative humidity ranges of 5%-10%, 80%-88% and 99%-100%. These experimental data show that the maximum differences of the calibration factors for Rn-222 and Rn-220 are 10.13% and 14.42%, respectively. The detection efficiency of Hynu EIRM-II was less affected by humidity. The measurement data of Rn-222 and Rn-220 by the Hynu EIRM-II can provide references for further improvement of radon monitors to accurately measure radon and thoron concentration.
作者机构:
[Liu, Gang] Hengyang Normal Univ, Coll Math & Stat, Hunan Prov Key Lab Intelligent Informat Proc & App, Hengyang, Peoples R China.;[Ponnusamy, Saminathan] Indian Inst Technol Madras, Dept Math, Chennai, India.;[Ponnusamy, Saminathan] Lomonosov Moscow State Univ, Moscow Ctr Fundamental & Appl Math, Moscow, Russia.;[Ponnusamy, Saminathan] Indian Inst Technol Madras, Dept Math, Chennai 600036, India.
通讯机构:
[Saminathan Ponnusamy] D;Department of Mathematics, Indian Institute of Technology Madras, Chennai, India<&wdkj&>Lomonosov Moscow State University, Moscow Center of Fundamental and Applied Mathematics, Moscow, Russia
摘要:
In order to improve the classical Bohr inequality, we explain some refined versions for a quasi-subordination family of functions in this paper, one of which is key to build our results. Using these investigations, we establish an improved Bohr inequality with refined Bohr radius under particular conditions for a family of harmonic mappings defined in the unit disk D ${\mathbb {D}}$ . Along the line of extremal problems concerning the refined Bohr radius, we derive a series of results. Here, the family of harmonic mappings has the form f = h + g ¯ $f=h+\overline{g}$ , where g ( 0 ) = 0 $g(0)=0$ , the analytic part h is bounded by 1 and that | g ′ ( z ) | ≤ k | h ′ ( z ) | $|g^{\prime }(z)|\le k|h^{\prime }(z)|$ in D ${\mathbb {D}}$ and for some k ∈ [ 0 , 1 ] $k\in [0,1]$ .
摘要:
Photoelectric catalytic and solar cells are two effective ways to solve the global energy shortage and en-vironmental pollution problems. However, low carrier separation efficiency has been becoming a common problem of current photocatalytic water decomposition and solar cells. In this work, both the electronic structures and optical properties of Janus MoSSe/MoGeSiN4 vdW heterostructures were systematically studied by density functional theory. The results show that the Janus MoSSe/MoGeSiN4 vdW hetero-structure with Se/Ge interfacial contact (Se/Ge heterostructure) is a direct band gap semiconductor. Interestingly, for the Se/Ge heterostructure, spatial separation of the photo-generated electrons and holes is expected, due to the conduction band minimum (CBM) and the valence band maximum (VBM) separately locating on the MoGeSiN4 and MoSSe layer. Besides, the Se/Ge heterostructure not only exhibits con-siderable absorption index in the visible light range but also maximum theoretical photoelectric conversion efficiency approaches 26.4 %, which can be furthermore enhanced by varying the layer distance and biaxial strain. The Se/Ge heterostructure shows high carrier mobility, obvious carrier separation, notably visible light absorption and tunable photoelectric properties, making it promising candidates for novel two di-mensional photocatalysis devices and solar cells.(c) 2023 Elsevier B.V. All rights reserved.
通讯机构:
[Fuliang Jiang] S;School of Resource and Environment and Safety Engineering, University of South China, Hengyang, China<&wdkj&>School of Safety and Management Engineering, Hunan Institute of Technology, Hengyang, China<&wdkj&>School of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, China<&wdkj&>Hunan Provincial Engineering Research Center for Uranium Mineral Exploration Technology, Hengyang, China
关键词:
Similar material;Orthogonal design;Uranium-bearing quasi-granite;Sensitivity analysis;Regression analysis;Radon diffusion coefficient
摘要:
Preparing similar materials of uranium-bearing granite surrounding rocks in high-level radioactive waste geological disposal repository is the prerequisite for the similar simulation test of the radon exhalation mechanism. The samples of uranium-bearing granite were prepared based on the model similarity principle. The optimized proportion of the samples was obtained by testing their density, compressive strength, elastic modulus, and tensile strength and conducting polar sensitivity analysis and quadratic multiple regression analysis. The radon diffusion coefficient and other properties between the sample and the original rock were verified by similarity ratio, and it meets the requirements.
摘要:
Spin-transport properties of molecular spin valves constructed by two chromium-salophene (CrSal) molecules connected with boron nitride (BN) atomic chains are investigated by applying a nonequiblium Green's function method with density functional theory. Nearly perfect spin-filtering effect can be found when the molecular spin valves are set in parallel magnetic configuration. In particular, the direction of the detected spin-polarization signal is reversible by tuning the types of BN atomic chains. Moreover, obvious magnetoresistance (MR) effects are also found in the molecular spin valves. More importantly, the MR ratio can be changed from about 359% to about 1.31 x 105% by adjusting the types of BN atomic chains. Our work provides a new avenue to realize high-performance multifunctional molecular spin valves.(c) 2023 Elsevier B.V. All rights reserved.
通讯机构:
[Javed Rehman] D;[Mohamed F. Shibl] R;Department of Physics, Baluchistan University of Information Technology, Engineering and Management Sciences (BUITEMS), Quetta, Pakistan<&wdkj&>Renewable Energy Program, Center for Sustainable Development, College of Arts and Sciences, Qatar University, Doha, Qatar
摘要:
Owing to their low cost, potassium-ion batteries (PIBs) are considered the best alternatives to Li-ion batteries (LIBs) due to the high abundance and reactivity of K. However, the large ionic size of K than Li, hinder the commercial availability of PIBs. Herein, DFT calculations are employed to shed light on the electrochemical performance of 2D SnO as an anode for PIBs. The electronic properties of bare SnO reveal semiconducting nature. However, it is metallic with a small amount of K-adsorption. As an anode for PIBs, 2D SnO has a very low average open-circuit voltage (OCV) of 0.292V with a high K storage capacity (398mAhg−1). Additionally, the outcomes of the AIMD simulations of the SnO monolayer are displayed with low and high content of K-loading which shows the thermal stability of the host material for PIBs. Eventually, we discuss the potassiation and depotassiation mechanism of the SnO sheet, which reveal fast charging and discharging rates due to the low activation energy barrier (0.07eV). Based on the above fascinating outcomes, the SnO monolayer could be a promising anode for rechargeable PIBs. The table of content (TOC) depicts the structural model of SnO monolayer as anode material and rapid charging and discharging processes for K-migration.
摘要:
The topological phase transitions (TPT) of light refers to a topological evolution from one type of spin-orbit interaction to another, which has been recently found in beam scattering at optical interfaces and propagation in uniaxial crystals. In this work, the focusing of off-axis and partially masked circular-polarization Gaussian beams are investigated by using of a full-wave theory. Moreover, two different types of spin-orbit interactions (i.e., spin-dependent vortex generation and photonic spin-Hall effect) in the focusing system are unified from the perspective of TPT. It is demonstrated that as the off-axis distance or the masked area increases, a TPT phenomenon in the focused optical field takes place, evolving from the spin-dependent vortex generation to the spin-Hall shift of the beam centroids. The intrinsic mechanism is attributed to the cylindrical symmetry-breaking of the system. This symmetry-breaking induced TPT based on the method of vortex mode decomposition is further examined. The main difference between the TPT phenomenon observed here and that trigged by oblique incidence at optical interfaces or oblique propagation in uniaxial crystals is also uncovered. Our findings provide fruitful insights for understanding the spin-orbit interactions in optics, providing an opportunity for unifying the TPT phenomena in various spin-orbit photonics systems.
作者机构:
[Ju, Sailong; Dai, Jiayu; Zhang, Enrui; Wu, Hongjian; Lai, Kang; Yang, Ming] Natl Univ Def Technol, Dept Phys, Changsha 410073, Peoples R China.;[Zhu, Hongen; Cui, Shengtao] Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230029, Peoples R China.;[Wang, Hanwen] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;[Yang, Bingjie; Li, Fangsen] Univ Sci & Technol China, Sch Nanotech & Nanobion, Hefei 230026, Peoples R China.;[Deng, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
通讯机构:
[Han, Zheng] S;[Zhu, Mengjian] C;[Dai, Jiayu] D;Department of Physics, National University of Defense Technology, Changsha, China<&wdkj&>State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, China<&wdkj&>Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China<&wdkj&>College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
关键词:
Models and simulations;Analysis and statistical methods
摘要:
Two models can be used to measure the radon exhalation rate with a ventilation chamber. The first is the custom model with a flow meter, and the second is the improved model without flow meter. As the established radon exhalation standard facilities can't simulate any medium to be measured by adjusting the radon exhalation rate and effective decay constants as required, numerical simulation is useful to compare the two models for measuring radon exhalation rate under different effective decay constants. Three different effective decay constants and two different radon exhalation rates were simulated for measuring radon exhalation rates, and the simulation results confirmed that the improved model is quick and accurate even when the radon exhalation rate is very low. While the custom model can only be used to calculate the radon exhalation rates when the ventilation rate is far larger than the effective decay constant, and it takes a long time for the radon concentration inside the ventilation chamber to be stable. Therefore, the improved model without flow meter is more accurate to measure the radon exhalation rate under different effective decay constants.
通讯机构:
[Zheng Zhou] D;Department of Physics, Hunan Institute of Technology, Hengyang, China
关键词:
Lee–Huang–Yang correction;Non-parity-time-symmetric potential;Self-bound states
摘要:
We numerically investigate the existence and stability of self-bound states forming in a one-dimensional binary bosonic condensate confined in non-parity-time (
$$\mathcal{PT}\mathcal{}$$
)-symmetric complex potentials under the influence of the Lee–Huang–Yang (LHY) correction. The linear spectrum of the non-
$$\mathcal{PT}\mathcal{}$$
-symmetric complex potentials may undergo phase transition where the eigenspectrum changes from partially complex to all real through the adjustment of the phase transition parameter. Below the phase transition, it is shown that the fundamental and dipole self-bound states can exist in different regions bifurcating from different discrete eigenvalues in the linear spectrum. The fundamental and dipole self-bound states are completely stable for the general case (i.e.,
$$\sigma =1$$
, with
$$\sigma $$
being the relative strength of the cubic self-interaction between atoms with respect to the quadratic LHY correction). Above the phase transition, the self-bound states are not stable for
$$\sigma =1$$
regardless of the value of the condensate norm. However, the fundamental self-bound states in the large condensate are able to become stable by decreasing
$$\sigma $$
to relatively small values.