The structure and electrical properties of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic. It was ascertained that th...The structure and electrical properties of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic. It was ascertained that the MnO addition did not cause remarkable change in crystal structure and microstructure. The MnO addition mainly displayed a hard effect on the electrical properties, an increase of coercive field （E） and mechanical quality factor （Qm） together with a decrease of dielectric constant （εr） and piezoelectric constant （d33）. An enhancement of electromechanical coupling factor （kp） with the MnO addition was obtained too. An essential relation between the piezoelectric properties and ferroelectric nature of the ceramics was detected. It was found that the piezoelectric properties of the ceramics highly depended on the corporative contribution of remanent polarization （Pt） and coercive field.展开更多
Double pulsed-laser-ablation is a promising method to prepare nanoparticle composites. The backward movement of the plume after the collision with counter-propagating shock wave has been observed in experiments. In th...Double pulsed-laser-ablation is a promising method to prepare nanoparticle composites. The backward movement of the plume after the collision with counter-propagating shock wave has been observed in experiments. In the present study, collision dynamics of the oppositely injected Si and Ge jets into a He background gas was numerically calculated as a simulation for double pulsed-laser-ablation. The experimentally observed backward movement was reproduced. The effect of distance between two jet exits on the distance of backward movement of the jet, B<sub>L</sub>, after the collision with the counter-propagating shock front was calculated to discuss the collision dynamics and to optimize the target distance for the experiment. We found that B<sub>L </sub>does not decrease monotonically with increasing distance between two jet exits, but has a maximum value at a certain distance. This behavior is discussed by calculating the expansion dynamics of an individual jet. Shock wave grows with time at the initial stage of the jet expansion and then attenuates;the density just behind the shock front for individual jet has a maximum value at a certain time and position. B<sub>L</sub> has a maximum value when the densities just behind the shock fronts for the individual jets have maximum values. This result is important for designing the appropriate distance between the two jet exits, i.e., the distance between the targets of double pulsed-laser-ablation.展开更多
Recent studies have correlated the chronic impact of ambient environmental pollutants like polycyclic aromatic hydrocarbons(PAHs)with the progression of neurodegenerative disorders,either by using statistical data fro...Recent studies have correlated the chronic impact of ambient environmental pollutants like polycyclic aromatic hydrocarbons(PAHs)with the progression of neurodegenerative disorders,either by using statistical data from various cities,or via tracking biomarkers during in-vivo experiments.Among different neurodegenerative disorders,PAHs are known to cause increased risk for Alzheimer’s disease,related to the development of amyloid beta(Aβ)peptide oligomers.However,the complex molecular interactions between peptide monomers and organic pollutants remains obscured.In this work,we performed an atomistic molecular dynamics study via GROMACS to investigate the structure of Aβ_(42) peptide monomer in the presence of benzo[a]pyrene,nicotine,and phenanthrene.Interestingly the results revealed strong hydrophobic,and hydrogen-bond based interactions between Aβpeptides and these environmental pollutants that resulted in the formation of stable intermolecular clusters.The strong interactions affected the secondary structure of the Aβ_(42) peptide in the presence of the organic pollutants,with almost 50%decrease in theα-helix and 2%–10%increase in theβ-sheets of the peptide.Overall,the undergoing changes in the secondary structure of the peptide monomer in the presence of the pollutants under the study indicates an enhanced formation of Aβpeptide oligomers,and consequent progression of Alzheimer’s disease.展开更多
基金the National Natural Science Foundation of China(No.50272044 and 50411140529)the Korea Science and Engineering Foundation(No.F01-2004-000-10084-0)
文摘The structure and electrical properties of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic. It was ascertained that the MnO addition did not cause remarkable change in crystal structure and microstructure. The MnO addition mainly displayed a hard effect on the electrical properties, an increase of coercive field （E） and mechanical quality factor （Qm） together with a decrease of dielectric constant （εr） and piezoelectric constant （d33）. An enhancement of electromechanical coupling factor （kp） with the MnO addition was obtained too. An essential relation between the piezoelectric properties and ferroelectric nature of the ceramics was detected. It was found that the piezoelectric properties of the ceramics highly depended on the corporative contribution of remanent polarization （Pt） and coercive field.
文摘Double pulsed-laser-ablation is a promising method to prepare nanoparticle composites. The backward movement of the plume after the collision with counter-propagating shock wave has been observed in experiments. In the present study, collision dynamics of the oppositely injected Si and Ge jets into a He background gas was numerically calculated as a simulation for double pulsed-laser-ablation. The experimentally observed backward movement was reproduced. The effect of distance between two jet exits on the distance of backward movement of the jet, B<sub>L</sub>, after the collision with the counter-propagating shock front was calculated to discuss the collision dynamics and to optimize the target distance for the experiment. We found that B<sub>L </sub>does not decrease monotonically with increasing distance between two jet exits, but has a maximum value at a certain distance. This behavior is discussed by calculating the expansion dynamics of an individual jet. Shock wave grows with time at the initial stage of the jet expansion and then attenuates;the density just behind the shock front for individual jet has a maximum value at a certain time and position. B<sub>L</sub> has a maximum value when the densities just behind the shock fronts for the individual jets have maximum values. This result is important for designing the appropriate distance between the two jet exits, i.e., the distance between the targets of double pulsed-laser-ablation.
基金conducted under the project“OPCRP2022003 Exposure to Cooking Ultrafine Particles and Neurodegenerative Disease:Clinical Exposure Studies and Computer Modeling”“11022021FD2905 Efficient thermal valorization of municipal sewage sludge in fluidized bed systems:Advanced experiments with process modeling”.
文摘Recent studies have correlated the chronic impact of ambient environmental pollutants like polycyclic aromatic hydrocarbons(PAHs)with the progression of neurodegenerative disorders,either by using statistical data from various cities,or via tracking biomarkers during in-vivo experiments.Among different neurodegenerative disorders,PAHs are known to cause increased risk for Alzheimer’s disease,related to the development of amyloid beta(Aβ)peptide oligomers.However,the complex molecular interactions between peptide monomers and organic pollutants remains obscured.In this work,we performed an atomistic molecular dynamics study via GROMACS to investigate the structure of Aβ_(42) peptide monomer in the presence of benzo[a]pyrene,nicotine,and phenanthrene.Interestingly the results revealed strong hydrophobic,and hydrogen-bond based interactions between Aβpeptides and these environmental pollutants that resulted in the formation of stable intermolecular clusters.The strong interactions affected the secondary structure of the Aβ_(42) peptide in the presence of the organic pollutants,with almost 50%decrease in theα-helix and 2%–10%increase in theβ-sheets of the peptide.Overall,the undergoing changes in the secondary structure of the peptide monomer in the presence of the pollutants under the study indicates an enhanced formation of Aβpeptide oligomers,and consequent progression of Alzheimer’s disease.
