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Efficient and stable perovskite-silicon two-terminal tandem solar cells

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Rare Metals 2020年第7期39卷 745-747页

作者： Mustafa Haider Jun-liang yang State Key Laboratory of Powder Metallurgy School of Physics and ElectronicsCentral South UniversityChangsha 410083China

In the past several years, perovskite solar cells (PSCs)exhibited unexpected breakthrough and rapid evolution,and the power conversion efficiency (PCE) of singlejunction PSCs has been increased significantly from 3.81 to25.2%[1, 2], resulting from materials engineering, interface engineering, crystallization engineering, fabrication engineering, etc.[3-5]. In the case of silicon solar cells.

关键词： perovskite breakthrough crystallization

Characteristics of Al_2O_3, MnS, and TiN inclusions in the remelting process of bearing steel

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 869-875页

作者： liang yang Guo-guang Cheng State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

The Al_2O_3, MnS, and TiN inclusions in bearing steel will deteriorate the steel's mechanical properties. Therefore, elucidating detailed characteristics of these inclusions in consumable electrode during the electroslag remelting process is important for achieving a subsequently clean ingot. In this study, a confocal scanning violet laser microscope was used to simulate the remelting process and observe, in real time, the behaviors of inclusions. The obtained images show that, after the temperature exceeded the steel solidus temperature, MnS and TiN inclusions in the specimen began to dissolve. Higher temperatures led to faster dissolution, and the inclusions disappeared before the steel was fully liquid. In the case of an observed Al_2O_3 inclusion, its shape changed from angular to a smooth ellipsoid in the region where the solid and liquid coexisted and it began to dissolve as the temperature continued to increase. This dissolution was driven by the difference in oxygen potential between the inclusion and the liquid steel.

关键词： characteristics inclusions remelting bearing steel confocal microscope

Remote sensing image encryption algorithm utilizing 2D Logistic memristive hyperchaotic map and SHA-512

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Science China(Technological Sciences) 2024年第5期67卷 1553-1566页

作者： LAI Qiang LIU Yuan yang liang School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang330013China

The two-dimensional Logistic memristive hyperchaotic map(2D-LMHM)and the secure hash SHA-512 are the foundations of the unique remote sensing image encryption algorithm(RS-IEA)suggested in this *** proposed map is formed from the improved Logistic map and the memristor,which has wide phase space and hyperchaotic range and is exceptionally excellent to be utilized in specific *** proposed image algorithm uses the permutation-assignment-diffusion *** generates two position matrices in a progressive manner to achieve an efficient random exchange of pixel positions,assignment is carried through on the image pixels of the permutated image to entirely remove the original image information,strengthening the relationship between permutation and diffusion,and loop diffusion in two different directions can use subtle changes of pixels to affect the whole *** random key and plain-image SHA-512 hash values are used to produce an additional key,which is then utilized to figure out the permutation parameters and the initial value of a chaotic *** experimental results with the average NPCR=99.6094%(NPCR:number of pixels change rate),average UACI=33.4638%(UACI:unified average changing intensity),100%pass rate of the targets in the test set,the average correlation coefficient is 0.00075,and the local information entropy is 7.9025,which shows that the algorithm is able to defend against a variety of illegal attacks and provide more trustworthy protection than some of the existing state-of-the-art algorithms.

关键词： chaos memristive hyperchaotic map remote sensing SHA-512 image encryption RS-IEA

New approach to determine common weights in DEA efficiency evaluation model

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Journal of Systems Engineering and Electronics 2010年第4期21卷 609-615页

作者： Feng yang Chenchen yang liang liangc Shaofu Du School of Management University of Science and Technology of China Hefei 230026 R R. China

Data envelopment analysis（DEA） is a mathematical programming approach to appraise the relative efficiencies of peer decision-making unit（DMU）,which is widely used in ranking ***,almost all DEA-related ranking approaches are based on the self-evaluation *** other words,each DMU chooses the weights it prefers to most,so the resulted efficiencies are not suitable to be used as ranking *** this paper proposes a new approach to determine a bundle of common weights in DEA efficiency evaluation model by introducing a multi-objective integer *** paper also gives the solving process of this multi-objective integer programming,and the solution is proven a Pareto efficient *** solving process ensures that the obtained common weight bundle is acceptable by a great number of *** a numeral example is given to demonstrate the approach.

关键词： data envelopment analysis(DEA) common weight ranking multi-objective programming.

Effect of Initial Goss Texture Sharpness on Texture Evolution and Magnetic Properties of Ultra-thin Grain-oriented Electrical Steel

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Acta Metallurgica Sinica(English Letters) 2017年第9期30卷 895-906页

作者： Rui-yang liang Ping yang Wei-Min Mao School of Materials Science and Engineering University ofScience and Technology BeijingBeijing 100083China

In this study, high- and low-grade grain-oriented electrical steels were used as the initial materials to produce 0.08-mm-thick sheet with one-step cold-rolling method. Electron backscattering diffraction analysis technique and X-ray diffraction texture analysis technique were adopted to investigate the effect of initial Goss texture sharpness on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The results showed that primary recrystal- lization and secondary recrystallization were the main processes that occurred during annealing. The induced factors for secondary recrystallization of two grades samples were not Consistent. The high-grade samples presented texture induction mechanism, while the low-grade samples revealed strong surface-energy induction mechanism. The initial Goss texture sharpness had a great impact on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The Goss texture component formed after primary recrystallization was stronger, and better magnetic properties were obtained at low frequencies. For low-grade samples, secondary recrystallization enhanced the intensity of Goss texture, and both grain size and texture contributed to better high-frequency magnetic properties after secondary recrystallization. By controlling the annealing process, the magnetic properties of low-grade products could be significantly improved, thus achieving conversion from low-grade to high-grade products.

关键词： Ultra-thin grain-oriented electrical steel Goss texture Secondary recrystallization Magnetic properties

Numerical Study of Propulsion Mechanism for Oscillating Rigid and Flexible Tuna-Tails

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Journal of Bionic Engineering 2011年第4期8卷 406-417页

作者： liang yang Yumin Su Qing xiao State Key Laboratory of Autonomous Underwater Vehicle Harbin Engineering University Harbin 150001 P. R. China Department of Naval Architecture and Marine Engineering University of Strathelyde Glasgow G40LZ United Kingdom

Numerical study on the unsteady hydrodynamic characteristics of oscillating rigid and flexible tuna-tails in viscous flow-field is performed. Investigations are conducted using Reynolds-Averaged Navier-Stokes （RANS） equations with a moving adaptive mesh. The effect of swimming speed, flapping amplitude, frequency and flexure amplitude on the propulsion performance of the rigid and flexible tuna-tails are investigated. Computational results reveal that a pair of leading edge vortices develop along the tail surface as it undergoes an oscillating motion. The propulsive efficiency has a strong correlation with various locomotive parameters. Peak propulsive efficiency can be obtained by adjusting these parameters. Particularly, when input power coeffcient is less than 2.8, the rigid tail generates larger thrust force and higher propulsive efficiency than flexible tail. However, when input power coefficient is larger than 2.8, flexible tail is superior to rigid tail.

关键词： tuna-tail RANS propulsion mechanism hydrodynamic characteristics viscous flow-fields

A Numerical-analytic Method for Quickly Predicting Springback of Numerical Control Bending of Thin-walled Tube

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Journal of Materials Science & Technology 2006年第5期22卷 713-720页

作者： Mei ZHAN He yang liang HUANG College of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072 China

Springback is one of important factors influencing the forming quality of numerical control （NC） bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process was put forward. The method is based on springback angle model derived using analytic method and simulation results from three-dimensional （3D） rigid-plastic finite element method （FEM）. The method is validated through comparison with experimental results. The features of the method are as follows：（1） The method is high in efficiency because it combines advantages of rigid-plastic FEM and analytic method. （2） The method is satisfactory in accuracy, since the field variables used in the model is resulting from 3D rigid-plastic FEM solution, and the effects both of axial force and strain neutral axis shift have been included. （3） Research on multi-factor effects can be carried out using the method due to its advantage inheriting from rigid-plastic FEM. The method described here is also of general significance to other bending processes.

关键词： Thin-walled tube Numerical control bending Springback Numerical-analytic method 3D rigid-plastic FEM

Performance analysis of UAV-based mixed underwater PLC-RF systems

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Digital Communications and Networks 2024年第5期10卷 1332-1340页

作者： Shenghai Chen liang yang Xianfu Lei College of Computer Science and Electronic Engineering Hunan University Key Laboratory of Intelligent Control Technology for Wuling-Mountain Ecological Agriculture in Hunan Province Huaihua University School of Information Science and Technology Southwest Jiaotong University

In this study,we analyzed the performance of an Unmanned Aerial Vehicle(UAV)-based mixed Underwater Power Line Communication-Radio Frequency(UPLC-RF) *** this network,a buoy located at the sea is used as a relay to transmit signals from the underwater signal source to the UAV through the PLC *** assume that the UPLC channel obeys a log-normal distribution and that the RF link follows the Rician *** this model,we obtained the closed-form expressions for the Outage Probability(OP),Average Bit-error-rate(ABER),and Average Channel Capacity(ACC).In addition,the asymptotic analysis of the OP and ABER was performed,and an upper bound for the average capacity was ***,the analytical results were verified by Monte Carlo simulation thereby demonstrating the effect of impulse noise and the altitude of the UAV on network performance.

关键词： ABER Underwater power line communication Average bit-error-rate ACC Average channel capacity OP Outage probability UAV Unmanned aerial vehicle UPLC

Development of through-thickness texture gradient and persistence of shear-type textures during annealing of commercial purity aluminium sheet processed by accumulative roll-bonding

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Journal of Materials Science & Technology 2018年第5期34卷 821-831页

作者： Saiyi Li liang yang Nan Qin School of Materials Science and Engineering Central South University Changsha 410083 China Key Laboratory of Nonferrous Metal Materials Science and Engineering of the Ministry of Education Central South University Changsha 410012 China

Ultrafine-grained commercial-purity aluminum（AA1070） sheets produced by four cycles of accumulative roll-bonding（ARB） without lubrication are subjected to annealing treatments in the temperature range from 250℃ to 400℃.Microstructures and microtextures in the surface and center regions of the ARBed and annealed sheets are measured by electron backscatter *** results show that annealing treatments at 325℃ or above lead to a reduction in the microstructure gradient but a significant through-thickness texture gradient different from that in the as-deformed *** center region is featured by the development of a strong cube texture at the expense of rolling *** the surface region,shear-type components are either enhanced or largely retained,showing a high persistency upon *** the grain structures are restored predominantly by continuous recrystallization in the surface region,a mixture of continuous and discontinuous recrystallization is envisaged for the center region.

关键词： Accumulative roll-bonding Texture Annealing Recrystallization Shear deformation