The fabrication of light-weight,highly impact-resistant,and energy-absorbent materials is urgently demanded in many facets of the society from body armor to aerospace engineering,especially under an extreme environmen...The fabrication of light-weight,highly impact-resistant,and energy-absorbent materials is urgently demanded in many facets of the society from body armor to aerospace engineering,especially under an extreme environment.Carbon nanotubes(CNTs),one of the strongest and toughest materials ever found,also have good conductivity,chemical stability,and thermal stability,etc,making them a competitive candidate as building blocks to help achieve the above goal.In this work,a kind of CNT network was prepared by using chlorosulfonic acid(CSA)to release the internal stress of super-aligned carbon nanotube films(SA-CNTF)and dendritic polyamide amine(PAMAM)to further introduce multiple hydrogen bonds and interlocking structures.The fabricated bioinspired carbon nanotube network films(PAMAM@C-CNTF)have a high toughness of 45.97 MJ/m3,showing an increase of 420%compared to neat SA-CNTF.More importantly,the anti-impact performance of the films(e.g.,with a maximum specific energy absorption of 1.40 MJ/kg under 80-100 m/s projectile impact)is superior to that of conventional protective materials from steel and Kevlar fiber,and also exceeds that of any other reported carbon-based materials.The hierarchical energy dissipation mechanism was further revealed through experiment and simulation.Additional functions including intelligent heating/anti-icing,ultraviolet protection,as well as electromagnetic interference shielding properties make these network films have great potential in practical multi-protection applications,especially under an extreme environment.展开更多
Following reform and opening up, China witnessed a rapid increase in legal cases, but the rate of increase has undergone a marked decline since 1997. The reasons this has occurred in a period of social transformation ...Following reform and opening up, China witnessed a rapid increase in legal cases, but the rate of increase has undergone a marked decline since 1997. The reasons this has occurred in a period of social transformation are threefold： a non-litigious dispute-settling mechanism, judicial policy and the credibility of the courts. A data analysis of the average annual rate of growth, the correlation coefficient and the respective proportions of solutions under the litigious and the non-litigious dispute-settling mechanisms indicates that the slowing of the rate of growth of litigation has been accompanied by a decrease in the role of the people＇s mediation system and the economic arbitration system. However, it is the strengthening of administrative dispute-settling mechanisms, a judicial policy of not accepting cases, the reform of litigation fees and a series of institutional cbnstructs aimed at judicial corruption that has curbed the rapid increase of legal cases.展开更多
基金supported by the National Key Basic Research Program of China(No.2022YFA1205400)the Chinese Postdoctoral Science Foundation(Nos.E1I41IR1 and E2911IR1).
文摘The fabrication of light-weight,highly impact-resistant,and energy-absorbent materials is urgently demanded in many facets of the society from body armor to aerospace engineering,especially under an extreme environment.Carbon nanotubes(CNTs),one of the strongest and toughest materials ever found,also have good conductivity,chemical stability,and thermal stability,etc,making them a competitive candidate as building blocks to help achieve the above goal.In this work,a kind of CNT network was prepared by using chlorosulfonic acid(CSA)to release the internal stress of super-aligned carbon nanotube films(SA-CNTF)and dendritic polyamide amine(PAMAM)to further introduce multiple hydrogen bonds and interlocking structures.The fabricated bioinspired carbon nanotube network films(PAMAM@C-CNTF)have a high toughness of 45.97 MJ/m3,showing an increase of 420%compared to neat SA-CNTF.More importantly,the anti-impact performance of the films(e.g.,with a maximum specific energy absorption of 1.40 MJ/kg under 80-100 m/s projectile impact)is superior to that of conventional protective materials from steel and Kevlar fiber,and also exceeds that of any other reported carbon-based materials.The hierarchical energy dissipation mechanism was further revealed through experiment and simulation.Additional functions including intelligent heating/anti-icing,ultraviolet protection,as well as electromagnetic interference shielding properties make these network films have great potential in practical multi-protection applications,especially under an extreme environment.
文摘Following reform and opening up, China witnessed a rapid increase in legal cases, but the rate of increase has undergone a marked decline since 1997. The reasons this has occurred in a period of social transformation are threefold： a non-litigious dispute-settling mechanism, judicial policy and the credibility of the courts. A data analysis of the average annual rate of growth, the correlation coefficient and the respective proportions of solutions under the litigious and the non-litigious dispute-settling mechanisms indicates that the slowing of the rate of growth of litigation has been accompanied by a decrease in the role of the people＇s mediation system and the economic arbitration system. However, it is the strengthening of administrative dispute-settling mechanisms, a judicial policy of not accepting cases, the reform of litigation fees and a series of institutional cbnstructs aimed at judicial corruption that has curbed the rapid increase of legal cases.
