期刊：
JOURNAL OF PHYSICS-CONDENSED MATTER,2021年33(28):285802 ISSN：0953-8984
通讯作者：
Haiou Wang<&wdkj&>Weishi Tan
作者机构：
[Wang, Haiou; Zhang, Hui; Huo, Dexuan; Wang, Yan] Hangzhou Dianzi Univ, Inst Mat Phys, Key Lab Novel Mat Sensor Zhejiang Prov, Hangzhou 310018, Peoples R China.;[Tan, Weishi] Hunan City Univ, Coll Informat & Elect Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413002, Peoples R China.;[Tan, Weishi] Nanjing Univ Sci & Technol, Dept Appl Phys, Key Lab Soft Chem & Funct Mat, Minist Educ, Nanjing 210094, Peoples R China.
通讯机构：
[Haiou Wang] K;[Weishi Tan] A;Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Material Physics, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China<&wdkj&>All-solid-state Energy Storage Materials and Devices Key Laboratory of Hunan Province, College of Information and Electronic Engineering, Hunan City University, Yiyang 413002, People's Republic of China<&wdkj&>Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
摘要：
Emergent phenomena at interfaces have been investigated intensely in pursuit of the next generation spintronics. In this work, we have integrated heterostructure consisting of paramagnetic (PM) metallic Pt and antiferromagnetic (AFM) insulator LaMnO(3)(LMO). High-quality Pt (3nm)/LMO (100nm) heterostructure has been obtained by pulsed laser deposition. The structure, lattice strain and magnetic properties of epitaxial Pt/LMO heterostructure are fully studied. Due to the high sensitivity of synchrotron radiation and the high quality of epitaxial layer, the reflection intensity of the 3 nm-thick ultrathin Pt layer and LMO layer can be detected, and then lattice strain can be calculated. The LMO layer is under relative large tensile strain (2.13%), while the Pt layer is under relative small compressive strain (-0.46%). Magnetization measurements suggest that unexpected ferromagnetic behavior is observed clearly in the PM-Pt/AFM-LMO heterostructure. Moreover, spin glass (SG) state and exchange bias (EB) is also observed in this heterostructure. SG state is observed as a result of competing magnetic orders and spin frustration at the Pt/LMO interface. The heterostructure shows the EB effect below blocking temperature (T(B)), which is much lower than the Néel temperature (T(N)) of LMO, suggesting that the EB is strongly related to the SG state. The EB originates from the coupling between the SG and AFM phases.
期刊：
Journal of Materials Science: Materials in Electronics,2021年32(14):18721-18727 ISSN：0957-4522
通讯作者：
Haiou Wang<&wdkj&>Weishi Tan
作者机构：
[Su, Kunpeng; Zhang, Hui; Wang, Haiou; Yang, Dexin; Huang, Shuai; Huo, Dexuan; Wang, Yan] Hangzhou Dianzi Univ, Inst Mat Phys, Key Lab Novel Mat Sensor Zhejiang Prov, Hangzhou 310018, Peoples R China.;[Tan, Weishi] Hunan City Univ, Coll Informat & Elect Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413002, Peoples R China.;[Tan, Weishi] Nanjing Univ Sci & Technol, Dept Appl Phys, Minist Educ, Key Lab Soft Chem & Funct Mat, Nanjing 210094, Peoples R China.
通讯机构：
[Haiou Wang] K;[Weishi Tan] A;Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Material Physics, Hangzhou Dianzi University, Hangzhou, China<&wdkj&>All-Solid-State Energy Storage Materials and Devices Key Laboratory of Hunan Province, College of Information and Electronic Engineering, Hunan City University, Yiyang, China<&wdkj&>Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, China
摘要：
In this paper, the effect of La3+ doping on the structure, charge ordering and magnetic properties of Sm0.5Ca0.5MnO3 manganite has been studied. A series of LaxSm0.5-xCa0.5MnO3 (x = 0, 0.25, 0.375, 0.5) samples are prepared by traditional solid state reaction. The crystal structures are studied by X-ray diffraction technology. The results show that they are single-phase and orthorhombic structures. The change of La3+ ion concentration does not change the crystal structure of the samples. The surface morphology and particle size of the samples are studied by scanning electron microscope. The average particle size of the samples is several micrometers. Energy-dispersive spectrometer is used to detect the composition of the samples. The results show that the actual element composition of the samples is consistent with that of the modulated element. Magnetic properties are analyzed by magnetization versus temperature (M-T) curves and magnetic hysteresis (M-H) loops. Below 50 K, the zero-field-cooling (ZFC) and field-cooling (FC) M-T curves diverge obviously, which is a typical feature of spin glass transition. The ZFC and FC M-T curves show a significant protuberance peak between 215 and 274 K, which represents the existence of charge-ordered (CO) anti-ferromagnetic (AFM) state. With increasing La3+ ion doping concentration, the CO temperature gradually decreases. Moreover, the butterfly-type M-H loops also confirm the existence of CO-AFM phase in samples. In a few words, the competition between FM and AFM phases determines the charge ordering behavior and magnetic properties of the samples.
摘要：
This theoretical work is devoted to investigating laser-irradiated Floquet topological magnon insulators on a two-dimensional checkerboard ferromagnet and corresponding topological phase transitions. It is shown that the checkerboard Floquet topological magnon insulator is able to be transformed from a topological magnon insulator into another one possessing various Berry curvatures and Chern numbers by changing the light intensity. Especially, we also show that both Tamm-like and topologically protected Floquet magnon edge states can exist when a nontrivial gap opens. In addition, our results display that the sign of the Floquet thermal Hall conductivity is also tunable via varying the light intensity of the laser field. (C) 2021 Elsevier B.V. All rights reserved.
期刊：
E3S Web of Conferences,2021年251:02018-null ISSN：2267-1242
通讯作者：
Song, Y.
作者机构：
[He H.; Song Y.] Business School, Central South University, No.932 Lushan South Road, Changsha, China;[Cao B.] College of Information and Electronic Engineering, Hunan City University, No.518 Yingbin East Road, Yiyang, China
通讯机构：
[Song, Y.] B;Business School, No.932 Lushan South Road, China
会议名称：
2021 International Conference on Tourism, Economy and Environmental Sustainability, TEES 2021
摘要：
In the environment of cloud computing, the data produced by massive users form a data stream and need to be protected by encryption for maintaining confidentiality. Traditional serial encryption algorithms are poor in performance and consume more energy without considering the property of streams. Therefore, we propose a velocity-aware parallel encryption algorithm with low energy consumption (LECPAES) for streams in cloud computing. The algorithm parallelizes Advanced Encryption Standard (AES) based on heterogeneous many-core architecture, adopts a sliding window to stabilize burst flows, senses the velocity of streams using the thresholds of the window computed by frequency ratios, and dynamically scales the frequency of Graphics Processing Units (GPUs) to lower down energy consumption. The experiments for streams at different velocities and the comparisons with other related algorithms show that the algorithm can reduce energy consumption, but only slightly increases retransmission rate and slightly decreases throughput. Therefore, LECPAES is an excellent algorithm for fast and energy-saving stream encryption.
摘要：
We propose a simple quasi-continuous monolayer graphene structure and achieve a dynamically tunable triple plasmon-induced transparency (PIT) effect in the proposed structure. Additional analyses indicate that the proposed structure contains a self-constructed bright-dark-dark mode system. A uniform theoretical model is introduced to investigate the spectral response characteristics and slow light-effects in the proposed system, and the theoretical and the simulated results exhibit high consistency. In addition, the influences of the Fermi level and the carrier mobility of graphene on transmission spectra are discussed. It is found that each PIT window exhibits an independent dynamical adjustability owing to the quasi-continuity of the proposed structure. Finally, the slow-light effects are investigated based on the calculation of the group refractive index and phase shift. It is found that the structure displays excellent slow-light effects near the PIT windows with high-group indices, and the maximum group index of each PIT window exceeds 1000 when the carrier mobility of graphene increases to 3.5 m2 V−1 s−1. The proposed structure has potential to be used in multichannel filters, optical switches, modulators, and slow light devices. Additionally, the established theoretical model lays a theoretical basis for research on multimode coupling effects.
期刊：
Results in Physics,2021年31:104880 ISSN：2211-3797
通讯作者：
Liezun Chen
作者机构：
[Wang, Zhiteng; Luo, Changyou; Ling, Xiaohui] Hunan Provincial Applied Basic Research Base of Optoelectronic Information Technology, College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China;[Chen, Liezun] All-Solid-State Energy Storage Materials and Devices Key Laboratory of Hunan Province, College of Information and Electronic Engineering, Hunan City University, Yiyang 413000, China;[Zhang, Lifu] International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Institute of Microscale Optoelectronic, Shenzhen University, Shenzhen 518060, China
通讯机构：
[Liezun Chen] A;All-Solid-State Energy Storage Materials and Devices Key Laboratory of Hunan Province, College of Information and Electronic Engineering, Hunan City University, Yiyang 413000, China
摘要：
We find analytically an exact soliton-like solution of cubic-quintic nonlinear Schrödinger equation (CQNLSE) with pure normal fourth-order dispersion (FOD). This exact solitary solution is “fixed-parameter” solitary wave, whose waveform is well described by hyperbolic secant function without oscillating tails. Those characteristics contribute importantly new information on solitons generation compared to the conventional pure-quartic soliton (PQS) in the absence of quintic nonlinearity. The numerical results verify that this exact solitary solution can preserve its shape. The formation of such solitary wave is a result of counterbalance between normal FOD as well as positive Kerr nonlinearity and negative quintic nonlinearity. The stability of such exact solitary wave is discussed as well. Although such exact solitary wave is linearly unstable in the presence of perturbation, our results disclose the role of quintic nonlinearity in the formation of high-energy PQS and its propagation, and also provide a way to control the generation of high-energy PQS laser pulse.
期刊：
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY,2021年21(10):5275-5281 ISSN：1533-4880
作者机构：
[Cao, Kesheng; Bai, Suzhen; Sun, Lijuan; Tian, Zhengshan] School of Chemistry and Environmental Engineering, Pingdingshan University, Pingdingshan 467000, China;[Tian, Hao] School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, China;[Li, Jitao] School of Physics and Telecommunications Engineering, Zhoukou Normal University, Zhoukou 466001, China;[Zhu, Qiuxiang] College of Information and Electronic Engineering, Hunan City University, Yiyang 413000, China
摘要：
Waste toner powders are considered as hazardous materials to human and living things, and should be properly recycled by many effective ways due to their fine particle sizes and complex components. In this paper, waste toner powders were used as raw materials to successfully synthesize three dimensions (3D) graphene oxide (GO) hydrogel by means of a one-pot chemical transformation based on the improved Hummers' method. The obtained 3D GO hydrogel has porous structure and abundant oxygen-containing functional groups because of the inherent 3D solid structure of waste toner powder and the strong oxidation process of the improved Hummers' method. Interestingly, the as-prepared 3D GO hydrogel with excellent adsorptive property could quickly remove Pb(II) ions (100 mg/L, removal efficiency of 96% and removal capacity of 144 mg/g) and methylene blue (50 mg/L, removal efficiency of 97% and removal capacity of 48 mg/g) from water, respectively. The preparation process of 3D GO hydrogel was simple and easy to operate, and the output can be moderately mass produced, thus it would provide a new and effective disposal way for the recycling and reusing of waste toner.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2021年23(6):3949-3962 ISSN：1463-9076
通讯作者：
Li, Hongjian
作者机构：
[Gao, Enduo; Xiong, Cuixiu; Zeng, Biao; Wu, Kuan; Li, Min; Chao, Liu; Ruan, Banxian; Zhang, Baihui; Li, Hongjian] Cent South Univ, Sch Phys & Elect, Changsha 410083, Peoples R China.;[Xiong, Cuixiu] Hunan City Univ, Coll Informat & Elect Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413000, Peoples R China.
通讯机构：
[Li, Hongjian] C;Cent South Univ, Sch Phys & Elect, Changsha 410083, Peoples R China.
摘要：
Graphene, a new two-dimensional (2D) material, has attracted considerable attention in recent years because of the metallic characteristics at terahertz frequencies. The phase coupling of multilayer graphene-coupled grating structures is normally used to realize multiple plasmon-induced transparency (PIT) spectral responses. However, the device becomes more complicated with the increase in the number of graphene layers. In this work, we propose a five-step-coupled pyramid-shaped monolayer graphene metamaterial and predict a dynamically controllable PIT with four transparency peaks for the first time in the monolayer graphene metamaterial. A tunable multi-switch and good slow light effect is predicted over the wide PIT window, and the maximum modulation depth is high up to 16.89 dB, which corresponds to 97.95%, while the time delay of the induced transparent window is as high as 0.488 ps, where the corresponding group refractive index is 586. The electric field distributions and quantum level theory are used to explain the physical mechanism of the PIT with four transparency peaks. The coupled mode theory (CMT) is employed to establish the mathematical model of the PIT with four transparency peaks, and the consistency between the simulated and the calculated results is nearly perfect. We believe that the pyramid-shaped monolayer graphene metamaterial could be useful in efficient filters, switches, and slow light devices.
作者机构：
[Yang, Ying; Qin, Feifei; Zhou, Mengyao] Nanjing Univ Posts & Telecommun, Coll Telecommun & Informat Engn, Peter Grunberg Res Ctr, Nanjing 210003, Peoples R China.;[Zhu, Qiuxiang] Hunan City Univ, Coll Informat & Elect Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413000, Peoples R China.;[Wang, Xiaoxuan; Wang, Ru] Southeast Univ, State Key Lab Bioelect, Nanjing 210096, Peoples R China.;[Zhang, Yanfang] Wuxi Inst Technol, Wuxi, Jiangsu, Peoples R China.
通讯机构：
[Zhu, Qiuxiang] H;Hunan City Univ, Coll Informat & Elect Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413000, Peoples R China.
关键词：
GaN membrane;F-P mode;Interface;Au film
摘要：
Transferable membranes were separated from the GaN epitaxial sheet with lift-off (LLO) technology. After the LLO process, the GaN membrane was removed onto various substrates, and then we can create different interfacial conditions, such as GaN attached with Si and GaN attached to Au. The substrate dependent photoluminescence (PL) properties of GaN membranes are studied by PL and time-resolution photoluminescence (TRPL) measurements in situ. Lasing oscillations are observed in the GaN membranes. The lasing features - which include the lasing spectra, Q factor, laser threshold, mode number, carrier dynamics and resonance mechanism - are systematically analyzed. We obtain, for GaN on a Si substrate, two series of ultraviolet lasing emissions with Fabry-Pe ' rot (F-P) mode at the same excitation position. Furthermore, lasing of the GaN membranes can be altered by Au film at the back end of it via the phenomenon of lasing mode merger and red shift. Comparing with the Si substrate, Au film on the back can balance the lasing oscillations through decreasing the threshold value, unifying the resonant modes, and increasing the carrier combination rate. This research provides a feasible method for the realization of flexible membrane lasers.
