To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying techn...To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying technology.The thermal reaction characteristics,AP decomposition behavior,and decomposition reaction pathways of Al/AP and Al@AP composite fuels were investigated using thermal analysis and Ab Initio Molecular Dynamics(AIMD)calculations.Under the influence of fine interfacial control,the low-temperature decomposition heat release peak of AP was delayed by 25.5℃,while the high-temperature decomposition peak was advanced by 36.2℃,leading to an increase in the decomposition heat release of AP from 410.7 J/g to 1068.7 J/g.Compared to the unclad structure,the apparent activation energy of AP in low-temperature decomposition increased,and slightly decreased during high-temperature decomposition in the Al@AP composite fuel.The physical model of AP decomposition shifted to the model with higher degrees of freedom and a faster diffusion rate,characterized by rapid bidirectional diffusion at the interface.Furthermore,due to fine interfacial control,the oxidation reaction pathway of Al has been altered,changing from the final products of AP decomposition(O_(2),Cl2,etc.)to the direct oxidation of AP decomposition intermediates(HClO,ClO_(2),etc.).This accelerated and strengthened the oxidation reaction process of Al.As a result of these performance improvements,the final combustion temperature of Al@AP in the Microcanonical Ensemble(NVE)system stabilized at 2370 K,which is significantly higher than 1400 K observed for Al/AP,indicating enhanced ignition and combustion performance.展开更多
Rice is one of the most consumed staple food plants around the world, and its plant architecture is very important to improve the grain yield （Zhang et al., 2008）. Plant height, leaf angle, tiller number and angle, ...Rice is one of the most consumed staple food plants around the world, and its plant architecture is very important to improve the grain yield （Zhang et al., 2008）. Plant height, leaf angle, tiller number and angle, and uniformity of panicle layer all can have strong effects on grain yield （Wang and Li, 2008）. During the long history of domestication, rice has been selected to develop uniform tiller height architecture that ensures panicle layer uniformity and ease of harvesting （Ma et al., 2009）, and is largely determined by the synchronic culm elongation.展开更多
In some cases of emergency backfill engineering projects, traditional backfill materials cannot meet the requirements of fast construction due to their long curing time. This study presents a new kind of rapid hardeni...In some cases of emergency backfill engineering projects, traditional backfill materials cannot meet the requirements of fast construction due to their long curing time. This study presents a new kind of rapid hardening controlled low strength material, which utilizes both rapid hardening sulphoaluminate cement and recycled fine aggregate from urban red brick construction waste. Totally, sixteen mixtures were prepared for the experiment with different cement-to-sand ratios and water-to-solid ratios. The flowability and bleeding rate of fresh mixture were measured to evaluate its workability, and the compressive strength of hardened mixture was tested to evaluate its rapid hardening and mechanical properties. Test results indicate that rapid hardening controlled low strength material containing recycled fine aggregate from urban red brick construction waste can achieve the desirable flowability, but the bleeding rate increases with the increase of flowability. In addition, 2-hour compressive strength can reach 0.08 - 0.12 MPa, and 4-hour compressive strength is 0.32 - 1.54 MPa, which can meet the requirements of emergency backfill construction. At last, based on the derived compressive strength, a fitting model for predicting compressive strength evolution of this new rapid hardening backfill material is developed, which fits accurately with these experimental data.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.52176099 and 52306130)the Applied Basic Research Project of Changzhou City,China(No.CJ20235033)the High-Performance Computation Laboratory of Hefei and Changzhou University,China.
文摘To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying technology.The thermal reaction characteristics,AP decomposition behavior,and decomposition reaction pathways of Al/AP and Al@AP composite fuels were investigated using thermal analysis and Ab Initio Molecular Dynamics(AIMD)calculations.Under the influence of fine interfacial control,the low-temperature decomposition heat release peak of AP was delayed by 25.5℃,while the high-temperature decomposition peak was advanced by 36.2℃,leading to an increase in the decomposition heat release of AP from 410.7 J/g to 1068.7 J/g.Compared to the unclad structure,the apparent activation energy of AP in low-temperature decomposition increased,and slightly decreased during high-temperature decomposition in the Al@AP composite fuel.The physical model of AP decomposition shifted to the model with higher degrees of freedom and a faster diffusion rate,characterized by rapid bidirectional diffusion at the interface.Furthermore,due to fine interfacial control,the oxidation reaction pathway of Al has been altered,changing from the final products of AP decomposition(O_(2),Cl2,etc.)to the direct oxidation of AP decomposition intermediates(HClO,ClO_(2),etc.).This accelerated and strengthened the oxidation reaction process of Al.As a result of these performance improvements,the final combustion temperature of Al@AP in the Microcanonical Ensemble(NVE)system stabilized at 2370 K,which is significantly higher than 1400 K observed for Al/AP,indicating enhanced ignition and combustion performance.
基金supported by funds from the National Transgenic Major Program Grants(No.2009ZX08009-022B)
文摘Rice is one of the most consumed staple food plants around the world, and its plant architecture is very important to improve the grain yield （Zhang et al., 2008）. Plant height, leaf angle, tiller number and angle, and uniformity of panicle layer all can have strong effects on grain yield （Wang and Li, 2008）. During the long history of domestication, rice has been selected to develop uniform tiller height architecture that ensures panicle layer uniformity and ease of harvesting （Ma et al., 2009）, and is largely determined by the synchronic culm elongation.
文摘In some cases of emergency backfill engineering projects, traditional backfill materials cannot meet the requirements of fast construction due to their long curing time. This study presents a new kind of rapid hardening controlled low strength material, which utilizes both rapid hardening sulphoaluminate cement and recycled fine aggregate from urban red brick construction waste. Totally, sixteen mixtures were prepared for the experiment with different cement-to-sand ratios and water-to-solid ratios. The flowability and bleeding rate of fresh mixture were measured to evaluate its workability, and the compressive strength of hardened mixture was tested to evaluate its rapid hardening and mechanical properties. Test results indicate that rapid hardening controlled low strength material containing recycled fine aggregate from urban red brick construction waste can achieve the desirable flowability, but the bleeding rate increases with the increase of flowability. In addition, 2-hour compressive strength can reach 0.08 - 0.12 MPa, and 4-hour compressive strength is 0.32 - 1.54 MPa, which can meet the requirements of emergency backfill construction. At last, based on the derived compressive strength, a fitting model for predicting compressive strength evolution of this new rapid hardening backfill material is developed, which fits accurately with these experimental data.
