作者机构：
[Zhao, Xu; Li, Shaozhen] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430023, Peoples R China.;[Wu, Sujuan; Zhong, Shoudeng; Wu, SJ; Wang, Shuqi] South China Normal Univ, Inst Adv Mat, South China Acad Adv Optoelect, Guangzhou 510006, Peoples R China.;[Wu, Sujuan; Zhong, Shoudeng; Wu, SJ; Wang, Shuqi] South China Normal Univ, South China Acad Adv Optoelect, Guangdong Prov Key Lab Quantum Engn & Quantum Mat, Guangzhou 510006, Peoples R China.
通讯机构：
[Wu, SJ ] S;[Li, SZ ] W;Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430023, Peoples R China.;South China Normal Univ, Inst Adv Mat, South China Acad Adv Optoelect, Guangzhou 510006, Peoples R China.;South China Normal Univ, South China Acad Adv Optoelect, Guangdong Prov Key Lab Quantum Engn & Quantum Mat, Guangzhou 510006, Peoples R China.
关键词：
potassium thiocyanate;diluted PEDOT:PSS solution;tin-based perovskite solar cells;photovoltaic performance
摘要：
The commercialized poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) is usually used as hole transport layers (HTLs) in tin-based perovskite solar cells (TPSCs). However, the further development has been restricted due to the acidity that could damage the stability of TPSCs. Although the PEDOT:PSS solution can be diluted by water to decrease acidity and reduce the cost of device fabrication, the electrical conductivity will decrease obviously in diluted PEDOT:PSS solution. Herein, potassium thiocyanate (KSCN) is selected to regulate the properties of PEDOT:PSS HTLs from the diluted PEDOT:PSS aqueous solution by water with a volume ratio of 1:1 to prepare efficient TPSCs. The effect of KSCN addition on the structure and photoelectrical properties of PEDOT:PSS HTLs and TPSCs have been systematically studied. At the optimal KSCN concentration, the TPSCs based on KSCN-doped PEDOT:PSS HTLs (KSCN-PSCs) demonstrate the champion power conversion efficiency (PCE) of 8.39%, while the reference TPSCs only show a champioan PCE of 6.70%. The further analysis demonstrates that the KSCN additive increases the electrical conductivity of HTLs prepared by the diluted PEDOT:PSS solution, improves the microstructure of perovskite film, and inhibits carrier recombination in TPSCs, leading to the reduced hysteresis effect and enhanced PCE in KSCN-PSCs. This work gives a low-cost and practical strategy to develop a high-quality PEDOT:PSS HTLs from diluted PE-DOT:PSS aqueous solution for efficient TPSCs.
摘要：
The structural, electronic and optical properties of MoSSe, PbS (111) and MoSSe/PbS (111) have been studied by the first-principles calculations, and the effect of V(S)on electronic and optical properties of MoSSe/PbS (111). When PbS (111) is stacked on MoSSe, an internal electric field and ohmic contact are formed at interlayer, and exhibited metal property. Compared with MoSSe and PbS (111) monolayer, MoSSe/PbS (111) heterostructure has higher absorption coefficients. Further analysis shows that this can be attributed to the orbital hybridization between the heterostructure layers. When V(S)is introduced, spin splitting occurs, making the spin-down channel below the Fermi level and inducing half-metallicity. What's more, Vs MoSSe/PbS (111) still performances better optical absorption coefficient. Based on these findings, the heterogeneous structures and defects not only affect the electronic properties, but also can be used as an effective method to regulate the electrical and optical properties, providing useful theoretical guidance for further experimental studies.
作者：
Fang, Chao;Chen, Xiqu;Zhang, Juanjuan;Xia, Xiaodong;Weng, George J.
期刊：
Journal of Physics D: Applied Physics,2023年56(4):045301 ISSN：0022-3727
通讯作者：
George J Weng
作者机构：
[Fang, Chao; Chen, Xiqu] Wuhan Polytech Univ, Dept Elect & Elect Engn, Wuhan 430023, Hubei, Peoples R China.;[Zhang, Juanjuan] Lanzhou Univ, Key Lab Mech Environm & Disaster Western China, Minist Educ China, Lanzhou 730000, Gansu, Peoples R China.;[Zhang, Juanjuan] Lanzhou Univ, Coll Civil Engn & Mech, Dept Mech & Engn Sci, Lanzhou 730000, Gansu, Peoples R China.;[Xia, Xiaodong] Cent South Univ, Sch Civil Engn, Changsha 410083, Peoples R China.;[Weng, George J.] Rutgers State Univ, Dept Mech & Aerosp Engn, New Brunswick, NJ 08903 USA.
通讯机构：
[George J Weng] D;Department of Mechanical and Aerospace Engineering, Rutgers University, New Brunswick, NJ 08903, United States of America
关键词：
graphene films;EMI shielding;electromagnetic plane wave;path;wrinkles;Monte Carlo
摘要：
In this paper, the electromagnetic interference shielding effectiveness (EMI SE) of multilayer graphene films is studied by the Monte Carlo (MC) method. First, we use the transfer matrix method to study the transmission and reflection of electric fields of the incident light passing through the graphene plane and the dielectric interface, and then determine the reflection and transmission probability of the light. In this way, the path of light can be obtained by the MC method. From the distance and emission direction of a large number of lights passing through the film, the expected value of the emitted light field is calculated and the EMI SE is determined. The obtained results of SE are shown to be in good agreement with several sets of experimental data. This model also takes into account the influence of wrinkles of graphene. It is found that EMI SE first increases and then decreases with the increase of wrinkle. The effects of film thickness, conductivity, and dielectric constant on EMI SE in the X-band frequency range are also investigated.
通讯机构：
[Lei, C; Liu, S ] W;Wuhan Univ, Inst Technol Sci, Wuhan 430072, Peoples R China.;Wuhan Univ, Sch Power & Mech Engn, Wuhan 430072, Peoples R China.
关键词：
RF compression cavity;dynamic atomic motion;ultrafast electron diffraction
摘要：
Ultrafast electron diffraction (UED) is a powerful tool for observing the evolution of transient structures at the atomic level. However, temporal resolution is a huge challenge for UEDs, mainly depending on the pulse duration. Unfortunately, the Coulomb force between electrons causes the pulse duration to increase continually when propagating, reducing the temporal resolution. In this paper, we theoretically design a radio frequency (RF) compression cavity using the finite-element method of electromagnetic-thermal coupling to overcome this limitation and obtain a high-brightness, short-pulse-duration, and stable electron beam. In addition, the cavity's size parameters are optimized, and a water-cooling system is designed to ensure stable operation. To the best of our knowledge, this is the first time that the electromagnetic-thermal coupling method has been used to study the RF cavity applied to UED. The results show that the RF cavity operates in TM010 mode with a resonant frequency of 2970 MHz and generates a resonant electric field. This mode of operation generates an electric field that varies periodically and transiently, compressing the electronic pulse duration. The electromagnetic-thermal coupling method proposed in this study effectively improves the temporal resolution of UED.
摘要：
Multipartite nonlocality is a measure of multipartite quantum correlations. In this paper we investigate the influence of symmetry-breaking perturbations upon ground-state nonlocality by considering several typical finite-size quantum models, including the transverse-field Ising chains, the XY ( XX ) chains, and the XXZ chains. We find that even a slight perturbation can reshape the nonlocality curve dramatically. For instance, in the XY chains, a perturbation can induce an oscillation behavior in the nonlocality curve. A clear microscopic mechanism for the results is proposed. Furthermore, we also connect the behaviors to the macroscopic symmetry properties of the chains and make some predictions on general models.
摘要：
为提升DV-Hop(distance vector-hop)算法定位精度水平,提出一种基于割圆术的DV-Hop全局优化(circle-cutting technique for global optimization o...展开更多 为提升DV-Hop(distance vector-hop)算法定位精度水平,提出一种基于割圆术的DV-Hop全局优化(circle-cutting technique for global optimization of DV-Hop algorithm,CTGO-DV-Hop)算法。该算法精确了最小跳数,引入权值模型对全部锚节点的平均单跳距离进行优化,并采用加权最小二乘递推算法对未知节点坐标进行拟合。实验测试多种因素对于算法的影响,结果表明,所提出的CTGO-DV-Hop算法表现出良好的性能,相较于DV-Hop、OCSLC-DV-Hop和WOCS-DV-Hop,平均定位误差的最大降幅为70%左右,适用于构建节点数目大、锚节点比例低的无线传感器网络系统。收起
通讯机构：
[Liu, HT ] W;[Liu, HT; Huang, ZY ] X;Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430023, Peoples R China.;Xiangtan Univ, Sch Phys & Optoelect, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;Hunan Univ, Hunan Key Lab Two Dimens Mat, Changsha 410082, Peoples R China.
关键词：
Janus transition metal dichalcogenides;heterostructures;electronic structure;multilayer
摘要：
The structure and electronic properties of bilayer, trilayer, and multilayer vertical Janus heterostructures are studied by first-principles calculation. By comparing the electronic structure of monolayer SMoS, monolayer SeMoS, and SMoS/SeMoS heterostructures, it has been found that, when SMoS forms heterostructures with more than two layers of Janus SeMoS, the band gap of the system changes from direct to indirect. In the Janus heterostructure system, significant charge transfer occurs between layers and a certain built-in electric field occurs. Due to the different contribution of Mo-d orbital coupling to CBM in different SeMoS layers, the band gap oscillates periodically with three layers of SeMoS. As the number of SeMoS layers in the heterostructure increases, the electrostatic potential difference and built-in electric field of the system increases continuously, resulting in the band gap value decreasing slowly. At the same time, the valence band offset value of the heterostructure constructed by SMoS and multilayer SeMoS decreases, and the conduction band offset value increases. These properties enrich the research and application of transition metal dichalcogenide-related heterostructures as optoelectronic and nanoelectronic devices.
关键词：
UAV;artificial potential field method;virtual target points;adaptive step size;path planning
摘要：
The obstacle avoidance system of a drone affects the quality of its flight path. The artificial potential field method can react quickly when facing obstacles; however, the traditional artificial potential field method lacks consideration of the position information between drones and obstacles during flight, issues including local minima, unreachable targets, and unreasonable obstacle avoidance techniques that lengthen flight times and consume more energy get encountered. Therefore, an improved artificial potential field method is proposed. First, a collision risk assessment mechanism was introduced to avoid unreasonable obstacle avoidance actions and reduce the length of unmanned aerial vehicle flight paths. Then, to solve the problem of local minimum values and unreachable targets, a virtual sub-target was set up and the traditional artificial potential field model was modified to enable the drone to avoid obstacles and reach the target point. At the same time, a virtual sub-target evaluation factor was set up to determine the reasonable virtual sub-target, to achieve a reasonable obstacle avoidance path compared to the traditional artificial potential field method. The proposed algorithm can plan a reasonable path, reduce energy consumption during flight, reduce drone turning angle changes in the path, make the path smoother, and can also be applied in complex environments.
摘要：
The oscillatory potential well can cause the mass points in it to move chaotically, which can be considered as a physical mechanism of chaos generation. Based on this physical mechanism, the oscillatory multi-well potential with multi-concave is used to generate controllable multi-scroll chaotic attractors with multi-wing. These attractors have two kinds of topological units: scroll and wing. The topological structure of the attractor depends on the shape of the potential well, that is, the wells and the concaves correspond to the scrolls and wings of the attractor. By constructing potential wells with different shapes, we can obtain attractors with different topological structure. The number of scrolls and wings of the chaotic attractor can be controlled by the oscillation amplitude of the potential well and damping coefficient, that is, stronger oscillation or smaller damping allows the mass points to enter the higher potential wells or concaves, resulting in attractors with more scrolls or wings. As the number of scrolls or wings increases, the attractors become more complex, as expressed by Poincare & PRIME; maps and quantified by the Kaplan-Yorke dimensions. Kaplan-Yorke dimensions of attractors can be adjusted continuously from 2 to 3 by the two control parameters. Finally, the results are confirmed by Multisim simulation circuit and actual analog circuit.
摘要：
We investigate the many-body localization (MBL) transitions in a spin-1/2 Heisenberg chain with an on-site random magnetic field by employing global quantum discord (GQD). We use the disorder-averaged GQD to estimate the MBL critical point, which is found to be around at $W_{c}=3.8$ by making a finite-size scaling analysis. We further compare our results of GQD with those of half-chain entanglement entropy (EE) that is promising in the study of MBL. We show that GQD can exclude the finite-size interference under the same condition, which implies that GQD is more robust than the half-chain EE in characterizing MBL.
通讯机构：
[Liu, XP ] W;Wuhan Polytech Univ, Sch Anim Sci & Nutr Engn, Wuhan 430023, Peoples R China.
关键词：
brown rice kernels;bonding parameters;discrete element;bonded particle model;orthogonal test
摘要：
Aiming to resolve the practical problem of brown rice kernels being easily broken due to overprocessing during processing (milling and polishing), brown rice kernels of Japonica rice, after hulling, were used as the research object in this study. Firstly, through a texture meter test, the discrete element bonding parameters (K-n is normal stiffness per unit area, K-tau is tangential stiffness per unit area, C-n is critical normal stiffness, C-tau is critical shear stiffness) were obtained. Secondly, a brown rice kernels' bonding particle model was established by EDEM, and then a second orthogonal rotational combination test was carried out to calibrate the discrete bonding parameters, K-n = 4.43 x 10(12) N/m(3), K-tau = 6.13 x 10(11) N/m(3), C-n = 2.55 x 10(7) Pa, and C-tau = 7.92 x 10(7) Pa. The error of parameter calibration was within 5%, and the results were able to reflect the actual situation more realistically. Finally, analysis of the crushing process of brown rice kernels showed that their ability to withstand shear damage was not as great as their pressure-bearing capacity. The design of the relevant mechanism and the setting of parameters should be based on the critical shear stiffness of brown rice kernels, and the actual shear force F-tau* set during the processing should be smaller than the theoretical critical shear force F-tau (F-tau* < F-tau = 9.11 N). This study can provide a theoretical basis for optimizing the key structure and operating parameters of rice milling machines and polishing machines to effectively solve the practical problem of increased crushing of brown rice kernels due to overprocessing.
