Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,none...Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,nonemissive displays,optical filters,among others.Although the current rigid electrochromic devices have shown emerging interest and developed rapidly,many applications(e.g.,wearable/deformable optoelectronics)are blocked due to their inflexible features.Herein,the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics.In this review,the current state-of-the-art achievements of flexible electrochromic devices(FECDs)are highlighted,along with their design strategies and the choice of electrochromic materials.The recent research progress of FECDs is reviewed in detail,and the challenges and corresponding solutions for real-world applications of FECDs are discussed.Furthermore,we summarize the basic fabrication strategies of FECDs and their potential applications.In addition,the development trend,the perspectives,and the outlook of FECDs are discussed at the end of this Review,which may provide recommendations and potential directions to advance the practical applications of FECDs.展开更多
In this article, we obtain Li-Yau-type gradient estimates with time dependent parameter for positive solutions of the heat equation that are different with the estimates by Li-Xu [21] and Qian [23]. As an application ...In this article, we obtain Li-Yau-type gradient estimates with time dependent parameter for positive solutions of the heat equation that are different with the estimates by Li-Xu [21] and Qian [23]. As an application of the estimate, we also obtained slight improvements of Davies' Li-Yau-type gradient estimate.展开更多
Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.Th...Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility.Here,we report a seeded growth strategy for the synthesis of TiO_(2-x)/WO_(3)·0.33H_(2)Ohetero-nanoparticles(HNPs)with networked wire-like structure of〜10 nm in diameters that enable the highly reversible light-responsive color switching properties.For the TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs,T P species self-doped in TiO_(2-x)nanoparticles(NPs)act as efficient sacrificial electron donors(SEDs)and Ti-O-W linkages formed between TiO2-x and WO30.33H2O NPs ensure the nanoscale interfacial contact,endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet(UV)illumination to achieve highly efficient color switching.The TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs exhibits rapid light response(<15 s)and long reversible color switching cycles(>180 times).We further demonstrate the applications of TiO_(2-x)/WO_(3)·0.33H_(2)O HNPs in ink-free,light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light.This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.展开更多
Precision and low damage grinding of aviation optical elements can effectively improve the overall processing efficiency.The mechanism of high-speed cross scuffing of multiple abrasive particles has become an importan...Precision and low damage grinding of aviation optical elements can effectively improve the overall processing efficiency.The mechanism of high-speed cross scuffing of multiple abrasive particles has become an important factor affecting the forming quality of workpiece.Interaction of abrasive trajectory determines machined surface and subsurface morphology and damage.According to the relative motion trajectory of wear particles on the workpiece surface,a theoretical model of the trochoidal trajectory intersection angle is proposed.High-speed scratches with different cross angles are experimentally obtained to explore the interference mechanism and damage accumulation of cross scratches.The results indicate that the Crack system I and Crack system II,produced by the two cross scratches,are mainly based on the stress principle and the strength principle,respectively.An increase in the damage radius is observed with a decrease in the crossing angle.Furthermore,as the duration of the normal cutting force decomposition curve at the entrance/exit of the intersection increases,the half-peak width also increases.The accumulation of cross-scratch damage promotes the propagation of deep subsurface lateral and median cracks.In other words,damage accumulation and interference mechanism formed by the cross scratches increase the longitudinal depth and lateral length of the damage.展开更多
基金the support from the “Qilu Young Scholar” program (62460082163097) of Shandong Universitythe National Natural Science Foundation of China (62105185)+1 种基金Shandong Excellent Young Scientists Fund Program (Overseas) (2022HWYQ-021)Guangdong Basic and Applied Basic Research Foundation (2022A1515011516)
文摘Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,nonemissive displays,optical filters,among others.Although the current rigid electrochromic devices have shown emerging interest and developed rapidly,many applications(e.g.,wearable/deformable optoelectronics)are blocked due to their inflexible features.Herein,the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics.In this review,the current state-of-the-art achievements of flexible electrochromic devices(FECDs)are highlighted,along with their design strategies and the choice of electrochromic materials.The recent research progress of FECDs is reviewed in detail,and the challenges and corresponding solutions for real-world applications of FECDs are discussed.Furthermore,we summarize the basic fabrication strategies of FECDs and their potential applications.In addition,the development trend,the perspectives,and the outlook of FECDs are discussed at the end of this Review,which may provide recommendations and potential directions to advance the practical applications of FECDs.
基金partially supported by the Yangfan project from Guangdong ProvinceNSFC(11571215)
文摘In this article, we obtain Li-Yau-type gradient estimates with time dependent parameter for positive solutions of the heat equation that are different with the estimates by Li-Xu [21] and Qian [23]. As an application of the estimate, we also obtained slight improvements of Davies' Li-Yau-type gradient estimate.
基金the Natural Science Foundation of Shandong Province(No.ZR2019JQ15)the National Natural Science Foundation of China(Nos.21671120,51972199).We would like to thank the Analytical Center for Structural Constituent and Physical Property of Core Facilities Sharing Platform,Shandong University for ESR and Raman characterizations.
文摘Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility.Here,we report a seeded growth strategy for the synthesis of TiO_(2-x)/WO_(3)·0.33H_(2)Ohetero-nanoparticles(HNPs)with networked wire-like structure of〜10 nm in diameters that enable the highly reversible light-responsive color switching properties.For the TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs,T P species self-doped in TiO_(2-x)nanoparticles(NPs)act as efficient sacrificial electron donors(SEDs)and Ti-O-W linkages formed between TiO2-x and WO30.33H2O NPs ensure the nanoscale interfacial contact,endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet(UV)illumination to achieve highly efficient color switching.The TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs exhibits rapid light response(<15 s)and long reversible color switching cycles(>180 times).We further demonstrate the applications of TiO_(2-x)/WO_(3)·0.33H_(2)O HNPs in ink-free,light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light.This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.
基金supported by the National Natural Science Foundation of China(Nos.51875406 and 51805365)Natural Science Foundation of Tianjin,China(No.19JCQNJC04000)。
文摘Precision and low damage grinding of aviation optical elements can effectively improve the overall processing efficiency.The mechanism of high-speed cross scuffing of multiple abrasive particles has become an important factor affecting the forming quality of workpiece.Interaction of abrasive trajectory determines machined surface and subsurface morphology and damage.According to the relative motion trajectory of wear particles on the workpiece surface,a theoretical model of the trochoidal trajectory intersection angle is proposed.High-speed scratches with different cross angles are experimentally obtained to explore the interference mechanism and damage accumulation of cross scratches.The results indicate that the Crack system I and Crack system II,produced by the two cross scratches,are mainly based on the stress principle and the strength principle,respectively.An increase in the damage radius is observed with a decrease in the crossing angle.Furthermore,as the duration of the normal cutting force decomposition curve at the entrance/exit of the intersection increases,the half-peak width also increases.The accumulation of cross-scratch damage promotes the propagation of deep subsurface lateral and median cracks.In other words,damage accumulation and interference mechanism formed by the cross scratches increase the longitudinal depth and lateral length of the damage.
