海平面的变化往往对区域生态环境、社会经济造成严重影响.通过对全球相对海平面变化(relative sea level,简称RSL)记录的再分析结果,合成了近2 Ma BP以来的全球RSL变化记录,分析了合成RSL记录对原始RSL记录数理特征的继承性,并基于频谱...海平面的变化往往对区域生态环境、社会经济造成严重影响.通过对全球相对海平面变化(relative sea level,简称RSL)记录的再分析结果,合成了近2 Ma BP以来的全球RSL变化记录,分析了合成RSL记录对原始RSL记录数理特征的继承性,并基于频谱、滤波等数理分析验证了合成RSL记录的合理性.在此基础上,讨论了合成RSL与大气CO_2浓度、中高纬度海域表层海水温度(sea surface temperature,简称SST)、全球大洋底栖氧同位素(δ^(18)O_B)等参数指标间的相关性,结果显示:(1)合成RSL不仅与原始RSL记录的变化趋势基本一致,继承了原始RSL记录对全球气候变化的响应特征,而且显示出合成RSL记录对地球轨道参数周期变化响应明显;(2)近2 Ma BP以来,在冰期-间冰期旋回中,合成RSL与δ^(18)O_B变化呈良好的负相关,相关系数r平均值可以达到约0.81,高于合成RSL与大气CO_2浓度及中高纬度海域SST变化的相关系数;(3)在地球轨道参数周期上,合成RSL与极地冰盖体积(δ^(18)O_B)的变化几乎同时,在偏心率周期上,合成RSL落后于SST和大气CO_2浓度变化;在斜率周期上,合成RSL落后于SST变化而领先于大气CO_2浓度变化.推测这些变化的诱导因素可能是在太阳辐射量改变的前提下,大气CO_2浓度及大洋SST变化对极地冰盖体积产生了差异影响,进而引起海平面发生变化.展开更多
Intense investigations have been attracted to the development of materials which can recon-figure into 3D structures in response to external stimuli.Herein we report on the design and self-folding behaviors of hydroge...Intense investigations have been attracted to the development of materials which can recon-figure into 3D structures in response to external stimuli.Herein we report on the design and self-folding behaviors of hydrogels composed of poly(ethylene glycol)methyl ether methacry-late(OEGMA)and 2-(2-methoxyethoxy)ethyl methacrylate(MEO2MA).Upon immersion into a variety of solvents at room temperature,the resulting P(MEO2MA-co-OEGMA)hy-drogel sheets self-fold into 3D morphologies,and the observed transformation in shape is reversible.We further show that composition of the gel,gaseous environment,and prepara-tion procedure play important roles in the self-folding behavior of the resulting hydrogels.This work provides a facile approach for fabricating self-folding hydrogels.展开更多
The N,S co-doped porous carbon nanofibers were fabricated by the carbonization of[Zn_(2)(tdc)_(2)(MA)]n MOFs/polyacrylonitrile nanofibers composite,which was produced by the electrospinning technology.The electrochemi...The N,S co-doped porous carbon nanofibers were fabricated by the carbonization of[Zn_(2)(tdc)_(2)(MA)]n MOFs/polyacrylonitrile nanofibers composite,which was produced by the electrospinning technology.The electrochemical results show that the N,S co-doped porous carbon nanofibers can achieve capacity of 201.2 mAh·g^(-1)at the current density of 0.05 A·g^(-1).Furthermore,the reversible capacity still has 161.3 mAh·g^(-1)even at a high current density of 1 A·g^(-1)after 600 cycles.The superior electrochemical performance shows that the N,S co-doped porous carbon nanofibers electrode material can be used as an ideal anode material for sodium-ion batteries.展开更多
文摘海平面的变化往往对区域生态环境、社会经济造成严重影响.通过对全球相对海平面变化(relative sea level,简称RSL)记录的再分析结果,合成了近2 Ma BP以来的全球RSL变化记录,分析了合成RSL记录对原始RSL记录数理特征的继承性,并基于频谱、滤波等数理分析验证了合成RSL记录的合理性.在此基础上,讨论了合成RSL与大气CO_2浓度、中高纬度海域表层海水温度(sea surface temperature,简称SST)、全球大洋底栖氧同位素(δ^(18)O_B)等参数指标间的相关性,结果显示:(1)合成RSL不仅与原始RSL记录的变化趋势基本一致,继承了原始RSL记录对全球气候变化的响应特征,而且显示出合成RSL记录对地球轨道参数周期变化响应明显;(2)近2 Ma BP以来,在冰期-间冰期旋回中,合成RSL与δ^(18)O_B变化呈良好的负相关,相关系数r平均值可以达到约0.81,高于合成RSL与大气CO_2浓度及中高纬度海域SST变化的相关系数;(3)在地球轨道参数周期上,合成RSL与极地冰盖体积(δ^(18)O_B)的变化几乎同时,在偏心率周期上,合成RSL落后于SST和大气CO_2浓度变化;在斜率周期上,合成RSL落后于SST变化而领先于大气CO_2浓度变化.推测这些变化的诱导因素可能是在太阳辐射量改变的前提下,大气CO_2浓度及大洋SST变化对极地冰盖体积产生了差异影响,进而引起海平面发生变化.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences
文摘Intense investigations have been attracted to the development of materials which can recon-figure into 3D structures in response to external stimuli.Herein we report on the design and self-folding behaviors of hydrogels composed of poly(ethylene glycol)methyl ether methacry-late(OEGMA)and 2-(2-methoxyethoxy)ethyl methacrylate(MEO2MA).Upon immersion into a variety of solvents at room temperature,the resulting P(MEO2MA-co-OEGMA)hy-drogel sheets self-fold into 3D morphologies,and the observed transformation in shape is reversible.We further show that composition of the gel,gaseous environment,and prepara-tion procedure play important roles in the self-folding behavior of the resulting hydrogels.This work provides a facile approach for fabricating self-folding hydrogels.
文摘The N,S co-doped porous carbon nanofibers were fabricated by the carbonization of[Zn_(2)(tdc)_(2)(MA)]n MOFs/polyacrylonitrile nanofibers composite,which was produced by the electrospinning technology.The electrochemical results show that the N,S co-doped porous carbon nanofibers can achieve capacity of 201.2 mAh·g^(-1)at the current density of 0.05 A·g^(-1).Furthermore,the reversible capacity still has 161.3 mAh·g^(-1)even at a high current density of 1 A·g^(-1)after 600 cycles.The superior electrochemical performance shows that the N,S co-doped porous carbon nanofibers electrode material can be used as an ideal anode material for sodium-ion batteries.
