Remote sensing image encryption algorithm based on novel hyperchaos and an elliptic curve cryptosystem

Remote sensing images carry crucial ground information,often involving the spatial distribution and spatiotemporal changes of surface elements.To safeguard this sensitive data,image encryption technology is essential.In this paper,a novel Fibonacci sine exponential map is designed,the hyperchaotic performance of which is particularly suitable for image encryption algorithms.An encryption algorithm tailored for handling the multi-band attributes of remote sensing images is proposed.The algorithm combines a three-dimensional synchronized scrambled diffusion operation with chaos to efficiently encrypt multiple images.Moreover,the keys are processed using an elliptic curve cryptosystem,eliminating the need for an additional channel to transmit the keys,thus enhancing security.Experimental results and algorithm analysis demonstrate that the algorithm offers strong security and high efficiency,making it suitable for remote sensing image encryption tasks.

Effect of particle gradation characteristics on yield stress of cemented paste backfill

Along with slurry concentration and particle density,particle size distribution(PSD)of tailings also exerts a significant influence on the yield stress of cemented paste,a non-Newtonian fluid.In this work,a paste stability coefficient(PSC)was proposed to characterize paste gradation and better reveal its connection to yield stress.This coefficient was proved beneficial to the construction of a unified rheological model,applicable to different materials in different mines,so as to promote the application of rheology in the pipeline transportation of paste.From the results,yield stress showed an exponential growth with increasing PSC,which reflected the proportion of solid particle concentration to the packing density of granular media in a unit volume of slurry,and could represent the properties of both slurry and granular media.It was found that slurry of low PSC contained extensive pores,generally around 20μm,encouraging free flow of water,constituting a relatively low yield stress.In contrast,slurry of high PSC had a compact and quite stable honeycomb structure,with pore sizes generally<5μm,causing the paste to overcome a higher yield stress to flow.

Changes in intestinal microflora in rats with acute respiratory distress syndrome

AIM:To implement high-throughput 16S rDNA sequencing to study microbial diversity in the fecal matter of rats with acute lung injury/acute respiratory distress syndrome(ALI/ARDS).METHODS:Intratracheal instillation of lipopolysaccharide was used to induce ALI,and the pathological changes in the lungs and intestines were observed.D-lactate levels and diamine oxidase(DAO)activities were determined by enzymatic spectrophotometry.The fragments encompassing V4 16S rDNA hypervariable regions were PCR amplified from fecal samples,and the PCR products of V4 were sequenced by Illumina MiSeq.RESULTS:Increased D-lactate levels and DAO activities were observed in the model group(P<0.01).Sequencing results revealed the presence of 3780 and4142 species in the control and model groups,respectively.The percentage of shared species was 18.8419%.Compared with the control group,the model group had a higher diversity index and a lower number of species of Fusobacteria(at the phylum level),Helicobacter and Roseburia(at the genus level)(P<0.01).Differences in species diversity,structure,distribution and composition were found between the control group and early ARDS group.CONCLUSION:The detection of specific bacteria allows early detection and diagnosis of ALI/ARDS.

Correlation of angiotensin converting enzyme gene polymorphism with perioperative myocardial protection under extracorporeal circulation

Objective:To observe the expression of angiotensin converting enzyme(ACE),angiotensinⅡ(AngⅡ),cardiac troponin 【cTnⅠ),creatine kinase isozymes(CK-MB) and muscle red protein(Myo) after cardiopulmonary bypass(CPB),and to investigate the association of polymorphisms in angiotensin converting enzyme genes and myocardial injury.Methods:Sixty-three patients suffered from rheumatic mitral stenosis and scheduled for mitral valve replacement with CPB, were randomly divided into three groups according polymorphisms in angiotensin converting enzyme genes:typeⅡ,type ID,type DD(each=21).Blood samples were withdrawn from artery before operation(T1),at the beginning of CPB(T2),30 min after CPB(T3),(T4) at the end of CPB(T5), 2 h after CPB(T6),6 h after CPB(17) to measure the expression of ACE,AngⅡ,cTnⅠ,CK-MB, Myo.Results:The level of ACE during and after CPB were significantly higher than those before CPB(P【0.05).As extension of CPB time,the expression of ACE was increased.The level of cTnⅠ, CK-MB,Myo after CPB were significantly higher than those before CPB(P【0.05).The level of cTnⅠ,CK-MB and Myo were highest at T7,T6 and T5 and T7,respectively.The level of ACE,AngⅡ,cTnⅠin patients with DD genotype was significantly higher than the ID andⅡgenotype(P【 0.05).Besides,the level of ACE,AngⅡin patients with ID genotype was significantly higher than the II(P【 0.05).Conclusions:There is certain correlation between CPB perioperative midterm ACE and cTnⅠ,Myo,CK-MB.ACE DD genotype is a susceptibility gene of the CPB perioperative myocardial injury.

Two-dimensional square-Au_(2)S monolayer:A promising thermoelectric material with ultralow lattice thermal conductivity and high power factor

The search for new two-dimensional(2 D)harvesting materials that directly convert(waste)heat into electricity has received increasing attention.In this work,thermoelectric(TE)properties of monolayer square-Au_(2)S are accurately predicted using a parameter-free ab initio Boltzmann transport formalism with fully considering the spin–orbit coupling(SOC),electron–phonon interactions(EPIs),and phonon–phonon scattering.It is found that the square-Au_(2)S monolayer is a promising room-temperature TE material with an n-type(p-type)figure of merit ZT=2.2(1.5)and an unexpected high n-type ZT=3.8 can be obtained at 600 K.The excellent TE performance of monolayer square-Au_(2)S can be attributed to the ultralow lattice thermal conductivity originating from the strong anharmonic phonon scattering and high power factor due to the highly dispersive band edges around the Fermi level.Additionally,our analyses demonstrate that the explicit treatments of EPIs and SOC are highly important in predicting the TE properties of monolayer square-Au_(2)S.The present findings will stimulate further the experimental fabrication of monolayer square-Au_(2)S-based TE materials and offer an in-depth insight into the effect of SOC and EPIs on TE transport properties.

Weldability of 1000 MPa Grade Ultra-low Carbon Bainitic Steel

Maximum hardness test in weld heat-affected zone（HAZ）,oblique Y-groove cracking test and mechanical property test of welding joint of 1 000 MPa grade ultra-low carbon bainitic steel were carried out,so as to research the weldability of the steel.The results show that the steel has lower cold cracking sensitivity,and preheating temperature of 100 ℃ can help completely eliminate cold cracks,generating good process weldability.The increase of preheating temperature can reduce the hardening degree of heat-affected zone.The strength of welding joint decreases and hardness reduces when heat inputs increase,and excellent mechanical properties can be obtained when low welding heat inputs are used.Fine lath bainites of different orientations combined with a few granular bainites that effectively split the original coarse austenite grains are the foundation of good properties.