摘要：
Considerable photovoltaic (PV) panels are installed on building roof, which are exposed to lightning strike at a high risk. Lightning electromagnetic (EM) field will induce a high voltage, which can damage the electronic devices of PV system. By using the method of moments, the EM coupling among the lightning channel and roof structure is modeled, and the induced voltage of PV array is calculated. The influences of building structure, roof material, and shape are discussed. The induced voltage is strongly dependent on the induced current on rooftop generated by the lightning EM field. Since the induced current produces an opposite magnetic field, it weakens the original lightning magnetic field and the presence of roof can lower the induced voltage. Occasionally, the induced voltage becomes higher for the roof with many crossbars and supporting legs, especially for the metal rooftop. The voltage rises as the roof height increases. Compared to the sloped roof, the distance between the flat roof and PV array is greater, and the effect of roof is relatively minor. To reduce the induced voltage, the arrangement of PV panels is investigated. The results can provide guidance for lightning protection design of rooftop PV system.
摘要：
The natural aluminosilicate nanoclay mineral (ANM) has found extensive application in photocatalysis due to its cost-effectiveness, excellent stability, and unique surface properties. The distinctive ANMs surface not only alters the surface characteristics of loaded photocatalysts and regulates the microenvironment of photochemical reactions but also actively participates as a photocatalyst itself, thereby making the roles of ANMs surfaces in photocatalytic reactions highly intricate. This review aims to highlight recent advancements in comprehending the influence of ANMs surfaces on photocatalysis. We commence by summarizing the structural features of ANMs surfaces as traditional supports, functional supports, and photocatalysts. Emphasis is placed on elucidating how the aluminosilicate structure, photochemical activity, and asymmetric structure impact the process of photocatalytic reactions. Particular attention is given to exploring the asymmetric photochemical activity exhibited by ANMs and its consequential unique structural effects. Finally, we summarize challenges faced and future developments pertaining to heterostructure design, enhancement mechanisms, and photochemical applications for ANMs in photocatalysis.
作者机构：
[Qichao Tian; Chi Ding; Xiaodong Qiu; Qinghao Meng; Kaili Wang; Fan Yu; Yuyang Mu] National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, China;School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha, China;Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China;Hefei National Laboratory, Hefei, China;[Can Wang] National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, China<&wdkj&>School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha, China
通讯机构：
[Yi Zhang] N;National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, China<&wdkj&>Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China<&wdkj&>Hefei National Laboratory, Hefei, China
摘要：
Layered material TaS2 hosts multiple structural phases and exotic correlated quantum states, including charge density wave (CDW), superconductivity, quantum spin liquid, and Mott insulating state. Here, we synthesized TaS2 monolayers in H and T phases using the molecular beam epitaxial (MBE) method and studied their electronic structures via angle-resolved photo-emission spectroscopy (ARPES). We found that the H phase TaS2 (H-TaS2) monolayer is metallic, with an energy band crossing the Fermi level. In contrast, the T phase TaS2 (T-TaS2) monolayer shows an insulated energy gap at the Fermi level, while the normal calculated band structure implies it should be metallic without any band gap. However, by considering Hubbard interaction potential U, further density functional theory (DFT) calculation suggests that monolayer T-TaS2 could be a CDW Mott insulator, and the DFT+U calculation matches well with the ARPES result. More significantly, the temperature-dependent ARPES result indicates that the CDW Mott state in the T-TaS2 monolayer is more robust than its bulk counterpart and can persist at room temperature. Our results reveal that the dimensional effect can enhance the CDW Mott state and provide valuable insights for further exploring the exotic properties of monolayer TaS2.
摘要：
Magnetosonic (MS) waves play a significant role in magnetospheric dynamics. They usually appear as electromagnetic fluctuations near the multiples of proton gyro-frequency. Recently, a distinct type of MS wave, quasi-electrostatic magnetosonic (QEMS) wave has been reported, of which only the electric field can be detected. Here we investigate the favorable generation conditions, spatial distribution, and frequency spectral features of the waves through a statistical study using Van Allen probes data. The results show that most (83%) of them are detected with a low plasma density n(e)<20 cm(-3), and the wave tends to be stronger in the lower density region. QEMS waves would also become stronger when the proton ring (10 keV) is more pronounced and the suprathermal (tens to hundreds of eV) proton population is larger. Most of the QEMS waves, especially the intense ones, are confined in the dayside equatorial region (|MLAT| < 3(degrees)). The wave frequencies are typically slightly below the multiples of proton gyro-frequency, and the wave amplitude gradually decreases with the increase of harmonic number. Our results further demonstrate that low plasma densities and abundant suprathermal protons are beneficial for intensifying QEMS waves and reveal the spatial distribution and frequency spectral characteristics of QEMS waves.
作者机构：
[Liu, Yaru; Xiong, Lingyun; Liu, YR] Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Hunan, Peoples R China.;[Liu, Yaru; Liu, YR] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Peoples R China.;[Xiong, Lingyun] Changsha Univ Sci & Technol, Chengnan Coll, Changsha 410076, Peoples R China.;[Zeng, Qing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Lai, Jianping] Southwest Univ Sci & Technol, Key Lab Testing Technol Mfg Proc, State Key Lab Environm friendly Energy Mat, State Key Lab Environm Friendly Energy Mat, Mianyang 621010, Peoples R China.
通讯机构：
[Liu, YR ] C;Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Peoples R China.
摘要：
The present work investigated the effect of destabilization time on the mechanical properties and microstructure evolution of high chromium cast iron, and scanning electron microscopy and electron probe microanalysis techniques were employed. The results show that the hardness of hypoeutectic high chromium cast iron is related to the size and volume fraction of secondary carbides precipitated from the matrix. The hardness of the alloy continues to rise due to the continuous increase of the volume fraction of the secondary carbide at the initial stage of destabilization. The alloy reaches its peak hardness value at 950 degrees C and 1000 degrees C for 1 hour holding time. The solid solubility of carbon and alloying elements in the matrix increases as the holding time extends, resulting in a large number of carbides redissolved into the matrix, making the hardness of the alloy decrease; the hardness of the alloy at 14 h is less than that at 10 min. Under 1050 degrees C, the size and density of the secondary carbide increase significantly; extending the holding time will lead to the continuous reduction of the carbide rod that provides strength, thus, the hardness curve shows a downward trend. The present work investigated the effect of destabilization time on the mechanical properties and microstructure evolution of high chromium cast iron, and scanning electron microscopy and electron probe microanalysis techniques were employed.
关键词：
Bound states in the continuum;Graphene;Absorption;Slow -light;Optical switch
摘要：
It is necessary to explore new mechanisms of plasmon-induced transparency (PIT) formation to achieve high-performance optical multifunction devices. Here, we introduced a symmetry-protected quasi bound states in the continuum (quasi-BIC) in the vicinity of the graphene plasmon resonance (GPR) mode to achieve a tunable plasmon-induced absorption (PIA) with 99.0 % and 99.4 %, which is the result of coupling between the bright modes. PIA supported by quasi-BIC has outstanding characteristics in both optical switching and slow light, with amplitude modulation depth up to 100 %, insertion loss below 0.04 dB, and group delay up to 10.3 ps. Significantly, it also solves the challenge that the absorption of the graphene system is reduced during dynamic modulation of electromagnetic waves. The dynamic modulation range of perfect absorption is up to 4.95 THz, which is much higher than any work that has been reported. We believe that the proposed structure provides a great reference for the future research direction of PIT and stimulates the development of high-performance multifunctional devices.
通讯机构：
[Cheng, F ] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410004, Peoples R China.
关键词：
Goos-Hanchen shifts;Semi-Dirac systems;Transport;Electric field;Magnetic field
摘要：
The semi-Dirac system has been of interest in recent years due to the exotic band structure, which is linear in one direction, but quadratic in a direction perpendicular to it. In the paper we study effects of electric and magnetic fields on the Goos-Hanchen (GH) shift in a semi-Dirac system. Our results show that the magnitude and direction of the GH shift depend on the incidence angle, the height and width of the electric barrier, and the magnetic field. The GH shifts exhibit the saltus step at the critical magnetic field. And the critical magnetic field decreases with the increase of the potential barrier thickness. The magnetic field plays a suppressive role on magnitude of the GH shift. Furthermore, applying the electric field in the III region, the magnitude of the GH shift can be significantly enhanced. The GH shift is a maximum at the point where the transmission probability reaches a minimum. These properties will be useful for the applications in semi-Dirac based electronic devices.
作者机构：
[XuanYun Zeng; Guang Zhong] School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410000, China;[XuanYun Zeng] Key Laboratory of Geospace Environment, Chinese Academy of Sciences, University of Science & Technology of China, Hefei 230026, China
摘要：
Due to the significant changes they bring to high latitude stratospheric temperature and wind, stratospheric sudden warmings (SSWs) can have an impact on the propagation and energy distribution of gravity waves (GWs). The variation characteristics of GWs during SSWs have always been an important issue. Using temperature data from January to March in 2014?2016, provided by the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission, we have analyzed global GW activity at 15?40 km in the Northern Hemisphere during SSW events. During the SSWs that we studied, the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere; the areas affected extended to the east of 90°W. During these SSWs, the potential energy density (ep) of GWs expanded and covered a larger range of longitude and altitude, exhibiting an eastward and downwardEp extension. The usually increased, while partially filtered by the eastward zonal winds. When zonal winds weakened or turnedEp Ep westward, began to strengthen. After SSWs, the usually decreased. These observations can serve as a reference for analyzing the Ep interaction mechanism between SSWs and GWs in future work.
摘要：
舌诊是中医望诊的重要手段,同时,温度与人体的健康息息相关。为了研究舌面的脏腑功能定位及舌象温度关系的反映,论文提出了一种红外技术的感兴趣区域(region of interest, ROI)模型研究方法。首先,利用葛立恒...展开更多 舌诊是中医望诊的重要手段,同时,温度与人体的健康息息相关。为了研究舌面的脏腑功能定位及舌象温度关系的反映,论文提出了一种红外技术的感兴趣区域(region of interest, ROI)模型研究方法。首先,利用葛立恒扫描法和Bezier曲线对多边形ROI模型进行改进;然后,借助U-Net分割网络将提取出的温度信息进行训练与学习,从而做到批量处理舌体温度信息;最后,利用HSV色彩模型进行3D可视化,达成舌象温度分区的可视化研究。此外,为了验证该方法的准确性,实验还对模型截取出的舌体进行了评价指标验证,准确度可以达到0.991 1,分割效果极佳。研究表明:改进后的红外信息提取技术既能直观地观察到舌体的分区状况,也可以完整保留舌体的信息变化,为中医的数据化提供了完整可行性方案。实现了舌体红外信息数据的提取与中医诊断技术的有机结合。解决了中医一体化望诊的舌体信息完整性及准确性问题。收起
作者机构：
[Shu-Zong Li; Jun-Shan Si; Zhixiong Yang; Wei-Bing Zhang] Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, School of Physics and Electronic Sciences, Changsha University of Science and Technology, Hunan, Changsha 410114, China
摘要：
Quantum anomalous Hall (QAH) effect with dissipationless edge channels offers innovative insight for designing the next-generation low-power electronic devices. Based on first-principles calculations and the tight-binding (TB) model, we predict rich QAH states with a tunable Chern number in single-layer ferromagnetic cerium monohalides CeX ( X = Cl, Br, I). These stable ferromagnetic single-layer materials have isotropic magnetocrystalline anisotropy in the x−y plane, which favors the adjustment of the topological state with an external magnetic field. A distinct Weyl nodal loop exists in the band structure of the CeX single layers without spin-orbit coupling (SOC). When SOC is included and all mirror symmetries are broken, QAH state can be realized. Intriguingly, QAH states with varying Chern number ( C=±1 ), two-dimensional Weyl semimetals and band gap periodically manifest as the magnetization direction rotates in the x−y plane. Furthermore, A TB model based on Slater-Koster framework is constructed to explain the origin of nontrivial band structure in CeX single layers. The CeX single layers exhibit remarkable topological states, providing an excellent platform for exploring low-power spintronic devices.
摘要：
Existing wafer pre-alignment methods suffer from high detection and maintenance costs, poor real-time performance, and the inability to simultaneously perform transparent wafer detection. In this paper, an improved visual detection method is proposed. Firstly, the method applies Gaussian filtering to remove noise and uses homomorphic filtering to enhance image contrast. Secondly, local OTSU threshold segmentation and morphological processing are employed for binarization, followed by perspective distortion correction. Finally, the sub-pixel edge rough fitting of the centroid is achieved using Zernike moments, and a geometric feature-based method is used to detect the corner positions of the wafer notches. After removing edge data, an iterative weighted least squares circle fitting algorithm is utilized for precise center fitting and center compensation to measure the wafer eccentricity. Experimental results demonstrate that compared to existing visual detection algorithms, this method can detect multiple types of wafers with low maintenance costs and achieve pre-alignment within 3.8 s, with positioning accuracy within 10 mm and a standard deviation of error of 0.0037 mm. It exhibits good real-time performance and robustness.
作者机构：
[Tao Yu] School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China;[Ji Zou] Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland;School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China;[J.W. Rao] School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China;[Ke Xia] School of Physics, Southeast University, Jiangsu 211189, China
通讯机构：
[Tao Yu] S;School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
摘要：
Dissipation in mechanics, optics, acoustics, and electronic circuits is nowadays recognized to be not always detrimental but can be exploited to achieve non-Hermitian topological phases or properties with functionalities for potential device applications, ranging from sensors with unprecedented sensitivity, energy funneling, wave isolators, non-reciprocal signal amplification, to dissipation induced phase transition. As elementary excitations of ordered magnetic moments that exist in various magnetic materials, magnons are the information carriers in magnonic devices with low-energy consumption for reprogrammable logic, non-reciprocal communication, and non-volatile memory functionalities. Non-Hermitian topological magnonics deals with the engineering of dissipation and/or gain for non-Hermitian topological phases or properties in magnets that are not achievable in the conventional Hermitian scenario, with associated functionalities cross-fertilized with their electronic, acoustic, optic, and mechanic counterparts, such as giant enhancement of magnonic frequency combs, magnon amplification, (quantum) sensing of the magnetic field with unprecedented sensitivity, magnon accumulation, and perfect absorption of microwaves. In this review article, we address the unified approach in constructing magnonic non-Hermitian Hamiltonian, introduce the basic non-Hermitian topological physics, and provide a comprehensive overview of the recent theoretical and experimental progress towards achieving distinct non-Hermitian topological phases or properties in magnonic devices, including exceptional points, exceptional nodal phases, non-Hermitian magnonic SSH model, and non-Hermitian skin effect. We emphasize the non-Hermitian Hamiltonian approach based on the Lindbladian or self-energy of the magnonic subsystem but address the physics beyond it as well, such as the crucial quantum jump effect in the quantum regime and non-Markovian dynamics. We provide a perspective for future opportunities and challenges before concluding this article.
作者机构：
[Xu, Liang; Huang, Lin; Chen, Tong] Jiangxi Univ Sci & Technol, Energy Mat Comp Ctr, Sch Energy & Mech Engn, Nanchang 330013, Peoples R China.;[Chen, Ke-Qiu; Wang, Jue] Hunan Univ, Sch Phys & Elect, Dept Appl Phys, Changsha 410082, Huna, Peoples R China.;[Ning, Feng] Nanning Normal Univ, Sch Phys & Elect, Nanning 530001, Peoples R China.;[Wu, Dan] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha 410114, Peoples R China.
通讯机构：
[Chen, KQ ] H;[Huang, L ] J;Jiangxi Univ Sci & Technol, Energy Mat Comp Ctr, Sch Energy & Mech Engn, Nanchang 330013, Peoples R China.;Hunan Univ, Sch Phys & Elect, Dept Appl Phys, Changsha 410082, Huna, Peoples R China.
摘要：
Manipulating the pi-electron magnetism of single-molecule junctions is an effective means to improve the electronic and spin-polarized thermoelectric transport properties. Here, using the density functional theory combined with the nonequilibrium Green's function method, we demonstrate that the electronic conductance (sigma) of molecular junctions (MJs) can be significantly enhanced by organic radicals due to the shifting of resonant states. Moreover, we find that the spin-dependent quantum interference (SDQI) effects can be largely influenced by organic radicals. The SDQI effects result in nearly 100% spin filtering efficiency in open-shell molecules and greatly enhance the Seebeck coefficients. As a result, the thermoelectric performances of open-shell MJs at room temperature are greatly improved through the combined effects of radicals and SDQI. In particular, the maximum ZT(sp) in the four radical junctions reaches up to 36.5. Our results show great potential for improving thermoelectric performance through the utilization of quantum interference and organic radical.
摘要：
Previous studies have shown that auroral kilometric radiation (AKR) can play an important role in the magnetosphere-atmosphere coupling and has the right-handed extraordinary (R-X), left-handed ordinary (L-O) and left-handed extraordinary (L-X) modes. However, the L-X mode has not been directly observed in the lower latitude magnetosphere yet, probably because of its very limited frequency range. Here, using observations of the Arase satellite on 6 September 2018, we present an AKR event with two distinct bands (8-20 and 300-1000 kHz) around the location: L = 8 and latitude = -37 degrees. The low (high) band is identified as the L-X (R-X) mode based on the polarization and frequency ranges. Simulations of 3-D ray tracing show that most of ray paths with 14 (11 and 18) kHz pass (miss) the location of Arase, basically consistent with observations. Our study provides direct evidence that the L-X mode can propagate from high latitudes downward to lower latitudes. Auroral kilometric radiation (AKR) is a widely existing radio emission with kilometric wavelength at the Earth, contributing to the magnetosphere-atmosphere coupling. Similar emissions have been observed on all magnetic planets of the solar system. Previous studies have shown that AKR primarily occurs in the R-X mode, with a small contribution in the L-O and L-X modes. The L-X mode at lower latitudes has not been directly observed so far, most likely due to its extremely limited frequency range. Here, we present an L-X mode (peak frequency similar to 14 kHz) in the lower latitude magnetosphere observed by the Arase satellite. Using the 3-D ray tracing method, we simulate ray paths with different initial wave parameters and source locations. Simulations show that ray paths with 14 (11 and 18) kHz pass (miss) the location of the Arase satellite and are highly dependent on initial wave parameters and the location of source. Our results provide a direct evidence that the L-X mode from high latitude source regions can propagate downward to lower latitudes under suitable conditions. This study enriches the understanding of AKR propagation characteristics in the magnetosphere. An auroral kilometric radiation (AKR) event with two distinct bands (8-20 kHz and 300-1000 kHz) is observed around the location: L = 8 and latitude = -37 degrees Based on the polarization and frequency ranges, the low (high) band AKR is identified as the L-X (R-X) mode 3-D ray tracing simulations show that L-X mode can propagate downward to lower latitudes, basically consistent with observations
摘要：
To address the safety concerns surrounding liquid electrolyte lithium-ion batteries, the development of a safe and reliable solid electrolyte with high ionic conductivity is of utmost importance. In recent years, the NASICON-type Li1.3Al0.3Ti1.7(PO4)(3) solid electrolyte has garnered increasing attention due to its impressive room temperature ionic conductivity and excellent chemical stability. However, its preparation is usually completed in high temperature up to 1000 degrees C, which is high energy consumption. Herein, F-doped Li1.3Al0.3Ti1.7P3O12 solid electrolytes were synthesized by molten salt assisted synthesis with AlF3 as the precursor and flux, which were prepared at 800 degrees C with relative density of 95.39% and room temperature lithium ionic conductivity of 1.14 x 10(-3) S cm(-1). XRD results show that F doping can inhibit the formation of impurity phase LiTiPO5 to a certain extent, and is beneficial to improve the conductivity and density of LATP solid electrolyte. FT-IR spectra show that the addition of F changes the structural peak of PO43- and increases the number of bridge oxygen, thus enhancing the structural stability of LATP solid electrolyte. The SEM results show that the addition of F can promote the growth of grain at low temperature, increase the density of LATP electrolyte, and reduce the energy consumption. EDS, XPS and TEM results show that F has been successfully doped into LATP solid electrolyte crystals.
摘要：
In this study, the electrical characteristics of depletion-mode AlGaN/GaN high-electron-mobility transistors (HEMTs) with a SiNx gate dielectric were tested under hydrogen exposure conditions. The experimental results are as follows: (1) After hydrogen treatment at room temperature, the threshold voltage V-TH of the original device was positively shifted from -16.98 V to -11.53 V, and the positive bias of threshold was 5.45 V. When the VDS was swept from 0 to 1 V with VGS of 0 V, the IDS was reduced by 25% from 9.45 A to 7.08 A. (2) Another group of original devices with identical electrical performance, after the same duration of hydrogen treatment at 100 C-degrees, exhibited a reverse shift in threshold voltage with a negative threshold shift of -0.91 V. The output characteristics were enhanced, and the saturation leakage current was increased. (3) The C-V method and the low-frequency noise method were used to investigate the effect of hydrogen effect on the device interface trap and border trap, respectively. It was found that high-temperature hydrogen conditions can passivate the interface/border traps of SiNx/AlGaN, reducing the density of interface/border traps and mitigating the trap capture effect. However, in the room-temperature hydrogen experiment, the concentration of interface/border traps increased. The research findings in this paper provide valuable references for the design and application of depletion-mode AlGaN/GaN HEMT devices.
