A lightweight symmetric image encryption cryptosystem in wavelet domain based on an improved sine map

In the era of big data,the number of images transmitted over the public channel increases exponentially.As a result,it is crucial to devise the efficient and highly secure encryption method to safeguard the sensitive image.In this paper,an improved sine map(ISM)possessing a larger chaotic region,more complex chaotic behavior and greater unpredictability is proposed and extensively tested.Drawing upon the strengths of ISM,we introduce a lightweight symmetric image encryption cryptosystem in wavelet domain(WDLIC).The WDLIC employs selective encryption to strike a satisfactory balance between security and speed.Initially,only the low-frequency-low-frequency component is chosen to encrypt utilizing classic permutation and diffusion.Then leveraging the statistical properties in wavelet domain,Gaussianization operation which opens the minds of encrypting image information in wavelet domain is first proposed and employed to all sub-bands.Simulations and theoretical analysis demonstrate the high speed and the remarkable effectiveness of WDLIC.

Research advances of magnesium and magnesium alloys worldwide in 2022

More than 4600 papers in the field of Mg and Mg alloys were published and indexed in the Web of Science(WoS)Core Collection database in 2022.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys are still the main research focus.Bio-Mg materials,Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Notable contributions to the research and development of magnesium alloys were made by Chongqing University(>200 papers),Chinese Academy of Sciences,Shanghai Jiao Tong University,and Northeastern University(>100 papers)in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the USA,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,and National University of Singapore in Singapore,etc.This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2022.Based on the issues and challenges identified here,some future research directions are suggested.

Research advances in magnesium and magnesium alloys worldwide in 2020

Research on magnesium alloys continues to attract great attention,with more than 3000 papers on magnesium and magnesium alloys published and indexed in SCI in 2020 alone.The results of bibliometric analyses show that microstructure control and mechanical properties of Mg alloys are continuously the main research focus,and the corrosion and protection of Mg alloys are still widely concerned.The emerging research hot spots are mainly on functional magnesium materials,such as Mg ion batteries,hydrogen storage Mg materials,and bio-magnesium alloys.Great contributions to the research and development of magnesium alloys in 2020 have been made by Chongqing University,Chinese Academy of Sciences,Central South University,Shanghai Jiaotong University,Northeastern University,Helmholtz Zentrum Geesthacht,etc.The directions for future research are suggested,including:1)the synergistic control of microstructures to achieve high-performance magnesium alloys with concurrent high strength and superior plasticity along with high corrosion resistance and low cost;2)further development of functional magnesium materials such as Mg batteries,hydrogen storage Mg materials,structural-functional materials and bio-magnesium materials;3)studies on the effective corrosion protection and control of degradation rate of magnesium alloys;4)further improvement of advanced processing technology on Mg alloys.

Research advances of magnesium and magnesium alloys worldwide in 2021

More than 4000 papers in the field of Mg and Mg alloys were published and indexed in Web of Science(WoS)Core Collection database in 2021.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys still are the main research focus.Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Significant contributions to the research and development of magnesium alloys were made by Chongqing University,Shanghai Jiaotong University,and Chinese Academy of Sciences in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the United States,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,etc..This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2021.Based on the issues and challenges identified here,some future research directions are suggested.

Research on the microstructure and properties of a multi-pass friction stir processed 6061Al coating for AZ31 Mg alloy

A 6061 Al coating for AZ31 Mg alloy was prepared by multi-pass friction stir welding(FSW)with different travel speeds.The mi-crostructure,mechanical properties of the interfacial region and the corrosion behavior of the coating were investigated systematically.The results indicate that the interfacial intermetallic compounds formed in the stir zone(SZ)consist of mainly Al12Mg17 and Al3Mg2.The inter-metallic compounds in the SZ are significantly increased when the travel speed is increased from 30 mm/min to 60 mm/min.Microhardness measurements and results of shear-tensile tests show that the mechanical properties are influenced by the intermetallic compounds formed in the SZ during FSW.Corrosion tests indicate that the 6061 Al coating can significantly improve the corrosion resistance of AZ31 plate.The 6061 Al coating obtained with a travel speed of 30 mm/min has a maximum corrosion potential E corr of-0.503 V VSE.

Microstructure and Corrosion Properties of Duplex-Structured Extruded Mg-6Li-4Zn-xMn Alloys

The extruded Mg-6 Li-4 Zn-xMn(x=0,0.4,0.8,1.2 wt%)alloys were prepared,and the microstructure of the test alloys was investigated by optical microscopy,scanning electron microscopy and transmission electron microscopy.The corrosion properties were determined by electrochemical measurements and immersion measurements in 3.5%NaCl solution.The results indicate that the extruded Mg-6 Li-4 Zn-xMn alloys are mainly composed ofα-Mg phase,β-Li phase,Mn precipitates and some intermetallic compounds(MgLi_(2)Zn).With the addition of Mn,stable corrosion products were formed on the surface of the test alloy,which can effectively inhibit further corrosion progress and improve the corrosion resistance.Mg-6 Li-4 Zn-1.2 Mn alloy exhibits the best corrosion resistance,attributed to grain refinement,the improvement of the stability of corrosion product film and uniform distribution of fine second phases.