CoCO_(3) with high theoretical capacity has been considered as a candidate anode for the next generation of lithium-ion batteries(LIBs).However,the electrochemical performance of CoCO_(3) itself,especially the cyclic ...CoCO_(3) with high theoretical capacity has been considered as a candidate anode for the next generation of lithium-ion batteries(LIBs).However,the electrochemical performance of CoCO_(3) itself,especially the cyclic stability at high current density,hinders its application.Herein,pure phase CoCO_(3) particles with different particle and pore sizes were prepared by adjusting the solvents(diethylene glycol,ethylene glycol,and deionized water).Among them,CoCO_(3) synthesized with diethylene glycol(DG-CC)as the solvent shows the best electrochemical performance owing to the smaller particle size and abundant mesoporous structure to maintain robust structural stability.A high specific capacity of 690.7 mAh/g after 1000 cycles was achieved,and an excellent capacity retention was presented.The capacity was contributed by diverse electrochemical reactions and the impedance of DG-CC under different cycles was further compared.Those results provide an important reference for the structural design and stable cycle performance of pure CoCO_(3).展开更多
This paper provides an investigation of the phase transition and spalling characteristic induced during shock loading and unloading in the pure iron and the FeMnNi alloy. The impact for the pure iron is symmetric and ...This paper provides an investigation of the phase transition and spalling characteristic induced during shock loading and unloading in the pure iron and the FeMnNi alloy. The impact for the pure iron is symmetric and with the same-thickness for both the flyer and the target plate. It is found that an abnormal multiple spalling happens in the pure iron sample as the pressure exceeds the α- ε transition threshold of 13 GPa. In the symmetric and same-thickness impact and reverse impact experiments of the FeMnNi alloy, two abnormal tension regions occur when the pressure exceeds the α - ε transition threshold of 6.3 GPa, and the reverse phase transition s - ~ begins below 4.2 GP. The experimental process is simulated successfully from the non-equilibrium mixture phase and Boettger＇s model. Such abnormal spalling phenomena are believed to relate to the shocked α - ε phase transition. The possible reasons for the abnormal multiple spalling, which occurs during the symmetric and same-thickness impact experiments of pure iron and FeMnNi alloy, are discussed.展开更多
设计了一种新型的平行排列液晶相位调制器(LC PM),可在纯相位的模式下进行相位调制,研究了液晶相位调制器的光学特性,理论上给予了分析.对畸变波前进行了调制,在1cm2的校正面积上,调制后的准确度PV(peak to valley)值接近λ/15(λ=0.632...设计了一种新型的平行排列液晶相位调制器(LC PM),可在纯相位的模式下进行相位调制,研究了液晶相位调制器的光学特性,理论上给予了分析.对畸变波前进行了调制,在1cm2的校正面积上,调制后的准确度PV(peak to valley)值接近λ/15(λ=0.6328μm),RMS(Root MeansSquare)可达到λ/100,斯特列尔比SR(Strehl Ratio)达到0.989.改变了传统的扭曲向列液晶器件难于进行纯相位调制和得到高准确度调制的缺点,达到了理想的效果.展开更多
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.51772060,51372052,51672059,51621091,and 51902102)Natural Science Foundation of Hunan Province(No.2020JJ5042)Postdoctoral Science Foundation of China(No.2020M672478).
文摘CoCO_(3) with high theoretical capacity has been considered as a candidate anode for the next generation of lithium-ion batteries(LIBs).However,the electrochemical performance of CoCO_(3) itself,especially the cyclic stability at high current density,hinders its application.Herein,pure phase CoCO_(3) particles with different particle and pore sizes were prepared by adjusting the solvents(diethylene glycol,ethylene glycol,and deionized water).Among them,CoCO_(3) synthesized with diethylene glycol(DG-CC)as the solvent shows the best electrochemical performance owing to the smaller particle size and abundant mesoporous structure to maintain robust structural stability.A high specific capacity of 690.7 mAh/g after 1000 cycles was achieved,and an excellent capacity retention was presented.The capacity was contributed by diverse electrochemical reactions and the impedance of DG-CC under different cycles was further compared.Those results provide an important reference for the structural design and stable cycle performance of pure CoCO_(3).
基金Project supported by the National Science Foundations of China (Grant Nos. 10776032 and 10902102)Science Foundation of China Academy of Engineering Physics (Grant Nos. 20060104 and 2009B0201014)
文摘This paper provides an investigation of the phase transition and spalling characteristic induced during shock loading and unloading in the pure iron and the FeMnNi alloy. The impact for the pure iron is symmetric and with the same-thickness for both the flyer and the target plate. It is found that an abnormal multiple spalling happens in the pure iron sample as the pressure exceeds the α- ε transition threshold of 13 GPa. In the symmetric and same-thickness impact and reverse impact experiments of the FeMnNi alloy, two abnormal tension regions occur when the pressure exceeds the α - ε transition threshold of 6.3 GPa, and the reverse phase transition s - ~ begins below 4.2 GP. The experimental process is simulated successfully from the non-equilibrium mixture phase and Boettger＇s model. Such abnormal spalling phenomena are believed to relate to the shocked α - ε phase transition. The possible reasons for the abnormal multiple spalling, which occurs during the symmetric and same-thickness impact experiments of pure iron and FeMnNi alloy, are discussed.
