通讯机构：
[Qing-Xia Ge; Wen-Jin Yin] S;School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China<&wdkj&>School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China<&wdkj&>Key Laboratory of Intelligent Sensors and Advanced Sensing Materials of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China
摘要：
Low activity and poor product selectivity of CO(2) reduction have seriously hampered its further practical application. Introducing p-block atoms to the catalyst is regarded as a promising strategy due to the versatility of p orbitals and diversity of p-block elements. Here, we systematically studied the influence of p-block atom X (X = C, N, O, S, and Se) on CO(2) catalytic properties on a Sn(200) surface by first-principles calculation. Our work shows that all the p-block atoms are relative stable with E(f) in the range of -5.11 to -3.59 eV. Further calculation demonstrates that the diversity of the p-block atoms results in unique CO(2) electrocatalytic activity and product selectivity. Interestingly, the p-block C atom shows bi-functional activity to form two-electron products HCOOH and CO, with the corresponding energy barriers remarkably low at about 0.19 eV and 0.28 eV. In particular, the p-block S(Se) atom appears to have striking HCOOH selectivity, with the energy barrier to form HCOOH only a quarter of that to form the CO product. This unusual behavior is mainly attributed to the adsorption strength and frontier orbital interaction between the p-block atom and intermediates. These findings can effectively provide a valuable insight into the design of highly efficient CO(2) electrocatalyst.
关键词：
Adsorption and desorption;Doped graphene;Molecular dynamics
摘要：
Two-dimensional materials have promised an important application as gas sensors due to their big surface areas. Although it's conceptually attractive, the real performance may be dramatically altered at finite temperatures. Therefore, to find out the underlying physical mechanism or dynamics at finite temperatures is of importance before any actual application. Here, we find that boron-doped graphene (BG) should be an ideal sensor to detect gas molecules such as NO2. Our results from first-principle molecular dynamics simulations show NO2 molecule can adsorb stably on BG at room temperature. Furthermore, its desorption time from BG is in the level of micro-seconds (ms), which has fully met the standards of industrial applications. The desorption time will be further decreased to the pico-seconds (ps) level at higher temperature, promising an opportunity for BG to detect the NO2 molecule using more accurate and sensitive measuring techniques, for example femtoseconds laser or ter-ahertz pulses.
作者机构：
[Tan, Yanliang; Lin, Fen; Hu, Tao; Yuan, Hongzhi; Mo, Yixiang; Fan, Zhongkai] Hengyang Normal Univ, Coll Phys & Elect Engn, Huangbai Rd 165, Hengyang 421008, Hunan, Peoples R China.;[Xie, Lin] Hengyang Normal Univ, Coll Math & Stat, Huangbai Rd 165, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Yanliang Tan] C;College of Physics and Electronic Engineering , Hengyang Normal University, Huangbai Road 165#, Hengyang, Hunan Province 421008 , China
摘要：
As Rn-222 decays, an alpha particle is emitted and the residual polonium nucleus recoils in the opposite direction. At the end of the recoil path, 88% of the polonium atoms have a positive charge and 12% are neutral. The electric potential distribution in the 60 ml hemispherical internal cell of the radon monitor based on electrostatic collection is studied for reducing the combined probability of the positively charged Po-218 and the OH− produced by the ionization of water vapour in the air. The COMSOL software is used to simulate the electric potential distribution in the internal cell of the radon monitor based on the electrostatic collection method at 27°C, a pressure of 0.1 Mpa. For improving the collection efficiency of Po-218 ions, the average collection time along vertical and oblique lines is calculated when the upper surface of the internal cell is plastic, uncharged metal and charged metal, respectively. Assuming that the gas in the internal cell is uniformly distributed, the results show that if the upper surface of the hemispherical internal cell is plastic or uncharged metal, the electric potential formed in the internal cell is more uniform, and it is beneficial to reduce the total collection time of the positively charged Po-218 ions, thereby improving collection efficiency. The simulation results can be used as an effective reference for optimizing the design of the internal cell structure of the radon monitor based on electrostatic collection method.
通讯机构：
[Qing-Xia Ge; Wen-Jin Yin] S;School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China<&wdkj&>School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China<&wdkj&>Key Laboratory of Intelligent Sensors and Advanced Sensing Materials of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China
摘要：
Designing photocatalysts with suitable band alignment and considerable carrier mobility is extremely important. Here, by means of first-principles calculation, we systematically investigated the structural, photoelectronic, and carrier mobility behavior of the two-dimensional Janus MoSSe/WSSe superlattice. The results show that both armchair-type (AN-SL) and zigzag-type (ZN-SL) superlattices are relatively stable with negative Ef values in the range of −2.35 to −1.16 eV. Band gap and band edge position calculations demonstrate that these superlattices are completely suitable for water splitting by visible light. Particularly, the interface contact of the superlattice can be spontaneously changed from type-I to type-II when N > 4, facilitating separation of photogenerated carriers. Furthermore, the hole carrier mobility (μh) in AN-SL can be effectively regulated from 1200 to 2200 cm2 V−1 s−1, much larger than that of the isolated components. Interestingly, the disparity of hole/electron carrier mobility is remarkably large with an approximately 20-fold difference, showing the potential in prohibiting the recombination of photogenerated carriers. This unique behavior is further illustrated by the relaxation times of carriers, where the lifetime of hole carriers is about 7 times larger than that of electron carriers. These findings suggest that forming a Janus superlattice is a promising approach for regulating the photoelectronic properties of semiconductors, providing a promising way to design high efficiency photocatalysts.
通讯机构：
[Lang Li] C;College of Computer Science and Technology, Hengyang Normal University, Hengyang, 421002, China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang Normal University, Hengyang, 421002, China
作者机构：
[Shao Lin CHEN] College of Mathematics and Statistics,Hengyang Normal University,Hengyang 421002,P.R.China;[Shao Lin CHEN] Hunan Provincial Key Laboratory of Intelligent Information Processing and Application,Hengyang 421002,P.R.China;Department of Mathematics,Indian Institute of Technology Madras,Chennai-600 036,India;[Saminathan PONNUSAMY] 马德拉斯理工学院
通讯机构：
[Shao Lin Chen] C;College of Mathematics and Statistics, Hengyang Normal University, Hengyang, P. R. China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang, P. R. China
关键词：
Harmonic K-quasiconformal mapping;Koebe type covering theorem;Koebe type distortion theorem;Radial John disk
作者机构：
[Dong, Jiansheng; Ouyang, Gang] Hunan Normal Univ, Sch Phys & Elect, Key Lab Low Dimens Quantum Struct & Quantum Contro, Key Lab Matter Microstruct & Funct Hunan Prov,Mini, Changsha 410081, Peoples R China.;[Zhao, Yipeng] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421008, Peoples R China.;[Yang, Guowei] Sun Yat Sen Zhongshan Univ, Sch Mat Sci & Engn, State Key Lab Optoelect Mat & Technol, Guangzhou 510275, Peoples R China.
通讯机构：
[Ouyang, G.] K;[Yang, G.] S;Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control, Ministry of Education, Key Laboratory for Matter Microstructure and Function of Hunan Province, School of Physics and Electronics, Hunan Normal University, Changsha, China
作者机构：
[Mengqin Gao; Wan-Ying Zhou; Yu-Xue Mo; Yanhong Deng; Liezun Chen; Yanliang Tan] College of Physics and Electronic Engineering, Hengyang Normal University, Henghua Road No. 16, Hengyang City, 421002, Hunan Province, China;[Tian Sheng] College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000, China;[Haiqing Zhou] Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China;[Kai Wang] Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, 76344, Germany
通讯机构：
[Yu-Xue Mo; Yanliang Tan] C;[Haiqing Zhou] K;College of Physics and Electronic Engineering, Hengyang Normal University, Henghua Road No. 16, Hengyang City, 421002, Hunan Province, China<&wdkj&>College of Physics and Electronic Engineering, Hengyang Normal University, Henghua Road No. 16, Hengyang City, 421002, Hunan Province, China<&wdkj&>Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China
摘要：
Here we proposed a novel approach to greatly enhance the electrochemical performance of Li–S batteries by designing a composite electrode material composed of a core-shell structure of S@Pt composite (sulfur content, 85%) grown on the S surface. The platinum (Pt) nanosheets provide physical barrier and strong chemical binding to anchor LiPSs and improve the electronic conductivity of S. Significantly, by introducing carbon nanofibers (CNFs) as the interlayer, we achieved outstanding Li–S battery with a high initial discharge capacity of 1040 mAh g−1 at 1.0C and a reversible capacity of 742 mAh g−1 after 350 cycles, demonstrating its excellent long-term cycling stability with a low capacity decay rate of 0.08% per cycle. According to the density functional theory (DFT) calculations, we proposed that the superior performance is attributed to the cooperative effects of the strong interfacial interaction between Pt (111) surface and the S8 molecule, and very low reaction energy of decomposition, −6.4 eV.
期刊：
Results in Physics,2022年42:105951 ISSN：2211-3797
通讯作者：
Zhen-Jun Yang
作者机构：
[Dai, Zhi-Ping; Wang, Yi-Cheng] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.;[Pang, Zhao-Guang; Yang, Zhen-Jun; Wang, Yue-Jiao] Hebei Normal Univ, Coll Phys, Hebei Key Lab Photophys Res & Applicat, Shijiazhuang 050024, Peoples R China.;[Pang, Zhao-Guang; Yang, Zhen-Jun; Wang, Yue-Jiao] Hebei Prov Semicond Photoelect Applicat Technol In, Shijiazhuang 050000, Peoples R China.
通讯机构：
[Zhen-Jun Yang] C;College of Physics, Hebei Key Laboratory of Photophysics Research and Application, Hebei Normal University, Shijiazhuang 050024, China<&wdkj&>Hebei Province Semiconductor Photoelectric Application Technology Innovation Center, Shijiazhuang 050000, China
关键词：
Optical nonlocal medium;Controllable anomalous hollow beam;Beam propagation and evolution
摘要：
The evolution properties of controllable anomalous hollow beams (CAHBs) in strongly nonlocal nonlinear medium are studied theoretically and numerically. The CAHB has a circular light intensity distribution, but there is a solid light intensity peak in the center. By changing initial parameters, the central and peripheral light intensities can be adjusted, so the CAHB can represent many different types of beams. The CAHBs in strongly nonlocal media shows a very rich variety of propagation characteristics. The transmission evolution properties of CAHBs, such as the light intensity distribution, the beam width and the on-axis light intensity, are mainly studied. The results show that by choosing appropriate initial parameters, the light intensity pattern of CAHBs can remain unchanged and form solitons, but also change periodically. The beam width of CAHBs can be widened or compressed in two transverse directions at the same time, or widened in one direction and compressed in the other direction. Some typical transmission characteristics are illustrated by numerical simulation, and the role of various parameters in transmission evolution is analyzed.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2022年24(45):27804-27811 ISSN：1463-9076
通讯作者：
Zeng, Jing
作者机构：
[Zeng, Jing] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
通讯机构：
[Zeng, Jing] C;College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, 421002, People's Republic of China.
摘要：
Dithiane is an ultra-short single-molecule insulator which has been confirmed in a recent experimental study [B. Zhang, M. H. Garner, L. Li, L. M. Campos, G. C. Solomon and L. Venkataraman, Chem. Sci., 2021, 12, 10299-10305]. In this work, we investigate the spin-dependent transport properties of dithiane sandwiched between conventional ferromagnetic electrodes using nonequilibrium Green's functions in combination with density functional theory. Here we explore the spin-transport properties of dithiane connected to two different ferromagnetic electrodes, namely, Ni and Co electrodes. An obvious spin-filtering effect can be observed when dithiane is coupled to Ni or Co electrodes. Moreover, it is found that the magnetoresistance (MR) effect strongly depends on the type of ferromagnetic electrodes, and a relatively high MR ratio is only observed in dithiane bonded to Co electrodes. The mechanisms for spin-filtering and MR effects in dithiane-based magnetic molecular junctions are also explained.
摘要：
Dynamical controls on terahertz (THz) wavefronts are crucial for many applications, but available mechanism requests tunable elements with sub-micrometer sizes that are difficult to find in the THz regime. Here, different from the local-tuning mechanism, we propose an alternative approach to construct wavefront-control meta-devices combining specifically designed metasurfaces and globally tuned graphene layers. Coupled-mode-theory (CMT) analyses reveal that graphene serves as a tunable loss to drive the whole meta-device to transit from one functional phase to another passing through an intermediate regime, exhibiting distinct far-field (FF) reflection wavefronts. As a proof of concept, we design/fabricate a graphene meta-device and experimentally demonstrate that it can reflect normally incident THz wave to pre-designed directions with different polarizations under appropriate gating voltages. We finally design a graphene meta-device and numerically demonstrate that it can generate vectorial THz beams with continuously varying polarization distributions upon gating. These findings pave the road to realizing a wide range of THz applications, such as sensing, imaging, and wireless communications.
通讯机构：
College of Physics and Electronic Engineering, Hengyang Normal University, Hunan Province, Hengyang, China
关键词：
Accelerator modelling and simulations (multi-particle dynamics, single-particle dynamics);Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc);Models and simulations;Radiation monitoring
摘要：
Developing an ultra-high sensitivity electrostatic collection radon monitor benefits the scientific experiments of China Jinping Underground Laboratory. Here, a one cubic meter electrostatic collection vessel with a multi-layer hemispherical metal grid was designed to increase the collection efficiency of positively charged Po-218 ions. The 3D model of the giant electrostatic collection vessel was constructed using the COMSOL Multiphysics simulation software, and the potential and electric field distributions in the vessel were simulated. Numerical simulation results were obtained according to the different radii and voltages applied to the grid. The electric field between the vessel wall and grid, between two grids, and between the grid and surface of the PIPS detector must be set uniformly to reduce the collection time of the positively charged Po-218 ions. Simulation results showed that setting a charged metal grid in the vessel can optimize the electric field distribution, and setting a two-layer charged metal grid in the giant vessel can further increase the cost performance. The average collection times of the electrostatic collection vessel with the two-layer grid along the vertical and oblique lines approximately 15% and 13% of that without the grid. The rates of positively charged Po-218 ions that could pass through the one and two-layer metal grids were 86.78% and 50%. Optimizing the electric field can greatly increase the sensitivity of radon monitors and reduce the humidity restrictions.
作者机构：
[Dai, Zhi-Ping; Wang, Yi-Cheng] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.;[Pang, Zhao-Guang; Yang, Zhen-Jun; Wang, Yue-Jiao] Hebei Normal Univ, Coll Phys, Hebei Key Lab Photophys Res & Application, Shijiazhuang 050024, Peoples R China.;[Liu, Xian-Jun] Hebei Univ, Postdoctoral Res Station Management Sci & Engn, Baoding 071002, Peoples R China.;[Liu, Xian-Jun] Hebei Acad Sci, Inst Applied Math, Postdoctoral Innovat Pract Base, Shijiazhuang, Peoples R China.;[Liu, Xian-Jun] Hebei Normal Univ, Sch Math Sci, Shijiazhuang 050024, Peoples R China.
通讯机构：
[Xian-Jun Liu] P;Postdoctoral Research Station of Management Science and Engineering, Hebei University, Baoding 071002, China<&wdkj&>Institute of Applied Mathematics, Postdoctoral Innovation Practice Base, Hebei Academy of Sciences, Shijiazhuang 050081, China<&wdkj&>School of Mathematical Sciences, Hebei Normal University, Shijiazhuang 050024, China
摘要：
In this paper, the propagation characteristics of adjustable anomalous hollow Gaussian beams are investigated in different cascaded systems composed of left-handed medium and right-handed medium. The propagation expressions of adjustable anomalous hollow Gaussian beams through different cascaded systems are derived, and the effects of negative refractive index and beam parameters on the propagation characteristics are analyzed in detail. It is found that when the negative refractive index changes, the position of the maximum axial intensity is different for different cascades. But the magnitude of the maximum axial intensity is not affected by the negative refractive index. The effects of negative refractive index and beam parameters on the beam width and intensity pattern evolution are also analyzed in detail. Although the propagation characteristics in this paper are obtained under certain parameters, it is very convenient to study the evolution characteristics under various conditions through the analytical formula obtained in this paper.
摘要：
Image hazing refers to artificially adding haze to a clear image to produce a natural haze effect. However, it might also be used as an image forgery for malicious purposes such as misleading tourists or spreading fake weather information. Up to the present, there are still no works specially designed for fake hazy image detection. Inspired by the fact that almost all artificial hazy images are synthesized based on the atmospheric scattering model (ASM), we observe that though synthetic and real hazy images are very difficult to be differentiated by naked eyes, there still exist some ASM-related imprints in synthesized hazy images. Specifically, the subtle differences between synthetic hazy images and real hazy ones are image saturation and haze distribution. In this work, we propose a dual-stream image hazing detection network, namely HDNet, to distinguish synthetic hazy images from natural hazy ones. One stream explicitly learns features from the image saturation channel, and the other one learns haze distribution features from the dark channel and gray level co-occurrence matrix. Moreover, to fuse well the learned features from two streams, we propose a progressive attention mechanism. A stage-wise learning strategy is exploited for network training, in which the learning process is divided into four sub-tasks that are completed stage-by-stage. Extensive experimental results prove that the proposed HDNet achieves desirable detection accuracy and robustness.
通讯机构：
[Gang Ouyang] K;Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Key Laboratory for Matter Microstructure and Function of Hunan Province, Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University, Changsha 410081, People's Republic of China
关键词：
band alignment;electron transfer rate;mixed-dimensional van der Waals heterostructures;power conversion efficiency
