In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are c...In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are closely related to the hydrogen bonds(H-bonds)network between water molecules.Therefore,it is crucial to analyze the relationship between these two aspects.In this paper,the infrared spectrum and motion characteristics of the stretching vibrations of the O-H bonds in one-dimensional confined water(1DCW)and bulk water(BW)in(6,6)single-walled carbon nanotubes(SWNT)are studied by molecular dynamics simulations.The results show that the stretching vibrations of the two O-H bonds in 1DCW exhibit different frequencies in the infrared spectrum,while the O-H bonds in BW display two identical main frequency peaks.Further analysis using the spring oscillator model reveals that the difference in the stretching amplitude of the O-H bonds is the main factor causing the change in vibration frequency,where an increase in stretching amplitude leads to a decrease in spring stiffness and,consequently,a lower vibration frequency.A more in-depth study found that the interaction of H-bonds between water molecules is the fundamental cause of the increased stretching amplitude and decreased vibration frequency of the O-H bonds.Finally,by analyzing the motion trajectory of the H atoms,the dynamic differences between 1DCW and BW are clearly revealed.These findings provide a new perspective for understanding the behavior of water molecules at the nanoscale and are of significant importance in advancing the development of infrared spectroscopy detection technology.展开更多
在光敏面上镀制荧光薄膜将紫外光转变为可见光，是提高CCD和CMOS图像传感器紫外响应灵敏度的一种有效方法。针对荧光薄膜入射界面的散射和反射损耗降低荧光发光强度的分析，研究在荧光薄膜上镀制增透膜和阻隔膜的灵敏度增强特性。采用...在光敏面上镀制荧光薄膜将紫外光转变为可见光，是提高CCD和CMOS图像传感器紫外响应灵敏度的一种有效方法。针对荧光薄膜入射界面的散射和反射损耗降低荧光发光强度的分析，研究在荧光薄膜上镀制增透膜和阻隔膜的灵敏度增强特性。采用真空热阻蒸发的镀膜方法分别制备了单层Lumogen荧光薄膜和MgF2/Lumogen复合膜。利用原子力显微镜，紫外可见近红外分光光度计，荧光光谱仪对两种样品的表面粗糙度，漫反射和透射光谱以及荧光发光光谱分别进行对比测试分析。结果表明：M g F2保护层降低了表面粗糙度，减小了入射界面的漫反射损耗，对500～700 nm的可见波段具有明显增透作用，也增强了Lumogen薄膜对紫外波段受激发射的荧光强度；同时，MgF2薄膜的抗损伤及水汽隔离性能对荧光薄膜紫外响应能力具有保护作用，为延长紫外CCD薄膜及器件的工作寿命提供了有效手段。展开更多
基金Supported by the Natural Science Foundation of China(51705326,52075339)。
文摘In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are closely related to the hydrogen bonds(H-bonds)network between water molecules.Therefore,it is crucial to analyze the relationship between these two aspects.In this paper,the infrared spectrum and motion characteristics of the stretching vibrations of the O-H bonds in one-dimensional confined water(1DCW)and bulk water(BW)in(6,6)single-walled carbon nanotubes(SWNT)are studied by molecular dynamics simulations.The results show that the stretching vibrations of the two O-H bonds in 1DCW exhibit different frequencies in the infrared spectrum,while the O-H bonds in BW display two identical main frequency peaks.Further analysis using the spring oscillator model reveals that the difference in the stretching amplitude of the O-H bonds is the main factor causing the change in vibration frequency,where an increase in stretching amplitude leads to a decrease in spring stiffness and,consequently,a lower vibration frequency.A more in-depth study found that the interaction of H-bonds between water molecules is the fundamental cause of the increased stretching amplitude and decreased vibration frequency of the O-H bonds.Finally,by analyzing the motion trajectory of the H atoms,the dynamic differences between 1DCW and BW are clearly revealed.These findings provide a new perspective for understanding the behavior of water molecules at the nanoscale and are of significant importance in advancing the development of infrared spectroscopy detection technology.
基金Supported by the National Basic Research Program of China(2007CB935303,2005CB724304)the National Natural Science Foundation of China(60778031)the Shanghai Leading Academic Discipline Project(S30502)
文摘在光敏面上镀制荧光薄膜将紫外光转变为可见光，是提高CCD和CMOS图像传感器紫外响应灵敏度的一种有效方法。针对荧光薄膜入射界面的散射和反射损耗降低荧光发光强度的分析，研究在荧光薄膜上镀制增透膜和阻隔膜的灵敏度增强特性。采用真空热阻蒸发的镀膜方法分别制备了单层Lumogen荧光薄膜和MgF2/Lumogen复合膜。利用原子力显微镜，紫外可见近红外分光光度计，荧光光谱仪对两种样品的表面粗糙度，漫反射和透射光谱以及荧光发光光谱分别进行对比测试分析。结果表明：M g F2保护层降低了表面粗糙度，减小了入射界面的漫反射损耗，对500～700 nm的可见波段具有明显增透作用，也增强了Lumogen薄膜对紫外波段受激发射的荧光强度；同时，MgF2薄膜的抗损伤及水汽隔离性能对荧光薄膜紫外响应能力具有保护作用，为延长紫外CCD薄膜及器件的工作寿命提供了有效手段。
基金The National Science Instrument Important Project(No.2012YQ17000407)the National Natural Science Foundation(Nos.61205156,61378060)Innovation Program of Shanghai Municipal Education Commission(No.14YZ095)
