The problems of electromagnetic wave(EMW)pollution in X and Ku bands(8–18 GHz)are becoming more and more serious.Therefore,it is urgent to design EMW absorbing materials with high-efficiency such as thin thickness,li...The problems of electromagnetic wave(EMW)pollution in X and Ku bands(8–18 GHz)are becoming more and more serious.Therefore,it is urgent to design EMW absorbing materials with high-efficiency such as thin thickness,lightweight,wide bandwidth and strong EMW absorption.Inspired by the biomorph of sea cucumber,Nb_(2)CT_(x) MXene@Co nitrogen-doped carbon nanosheet arrays@carbon fiber aerogels(Nb_(2)CT_(x)@Co-NC@CFA,Nb_(2)CT_(x)=niobium carbide)were constructed by self-assembly,in-situ chemical deposition and subsequent pyrolysis.The carbon fiber aerogel,as the basic skeleton of sea cucumber,forms lightweight three-dimensional interconnected conductive network,enhances the dielectric loss and extends the multiple reflection and absorption paths of EMW.As the tentacles of sea cucumber surface,Nb_(2)CT_(x) MXene and Co nitrogen-doped carbon nanosheet arrays exist rich heterogeneous interfaces,which play an important role in improving EMW polarization loss and optimizing impedance matching.The minimum reflection loss(RLmin)of Nb_(2)CT_(x)@Co-NC@CFA reaches−54.7 dB at 9.84 GHz(2.36 mm)with a low filling ratio of 10 wt.%and the effective absorption bandwidth(EAB)of Nb_(2)CT_(x)@Co-NC@CFA reaches 2.96 GHz(8.48–11.44 GHz)with 2.36 mm and 5.2 GHz(12.8–18 GHz)with 1.6 mm,covering most of X and Ku bands by adjusting thickness.The radar cross section(RCS)value of Nb_(2)CT_(x)@Co-NC@CFA is 26.64 dB·m^(2),which is lower than that of the perfect electrical conductor(PEC),indicating that Nb_(2)CT_(x)@Co-NC@CFA can effectively decrease the probability of the target being detected by the radar detector.This work provides ideas for design and development of EMW absorbing materials with high-efficiency EMW absorption in X and Ku bands.展开更多
When atoms are accelerated in the vacuum,entanglement among atoms will degrade compared with the initial situation before the acceleration.In this study,we propose a novel and interesting view that the lost entangleme...When atoms are accelerated in the vacuum,entanglement among atoms will degrade compared with the initial situation before the acceleration.In this study,we propose a novel and interesting view that the lost entanglement can be recovered completely when the high-dimensional spacetime is exploited,in the case that the acceleration is not too large,since the entanglement loss rate caused by the large acceleration is faster than the recovery process.We also calculate the entanglement change caused by the anti-Unruh effect and found that the lost entanglement could just be recovered part by the anti-Unruh effect,and the anti-Unruh effect could only appear for a finite range of acceleration when the interaction time scale is approximately shorter than the reciprocal of the energy gap in two dimensional spacetime.The limit case of zero acceleration is also investigated,which gives an analytical interpretation for the increase or recovery of entanglement.展开更多
This study aimed to develop a novel edible packaging film for the postharvest preservation of banana based on chitosan(CS)and persimmon peel extract(PPE).Scanning electron microscopy analysis showed that PPE was evenl...This study aimed to develop a novel edible packaging film for the postharvest preservation of banana based on chitosan(CS)and persimmon peel extract(PPE).Scanning electron microscopy analysis showed that PPE was evenly distributed in the CS matrix and Fourier transform infrared spectroscopy analysis showed that CS and PPE interacted to form hydrogen bonds,demonstrating good compatibility.Simultaneously,the addition of PPE also significantly improved the physical properties and antioxidant activity of the CS film.Among them,the CS film containing 10%PPE(CS-PPE 10)showed the optimal mechanical properties,water vapor barrier properties and oxygen barrier properties.The CS film containing 15%PPE(CS-PPE 15)exhibited the best thermal stability,UV-Vis barrier properties and antioxidant activity.In the experiment on banana preservation,CS-PPE 10 film obtained optimal performance on decreasing senescence spots,weight loss,fruit softening,and cell wall degradation,inhibiting the activities of polyphenol oxidase and cell wall-degrading enzymes and maintaining the content of total soluble sugar and ascorbic acid during the storage period.Consequently,CS-PPE 10 film was expected to be a novel edible packaging material to maintain banana quality and prolong shelf life.展开更多
基金financially supported by the National Natural Science Foundation of China and the Civil Aviation Administration of China(No.U1833118)the Open Project Program of High-Tech Organic Fibers Key Laboratory of Sichuan Province(No.PLN2022-10)+3 种基金the Science and Technology Plan Project of Chengdu City(2022-YF05-00411-SN)Science and Technology Planning Project of Sichuan Province(Nos.2023YFQ0090,2024YFHZ0218,2023YFN0016,and 2023YFQ083)Yibin Science and Technology Plan Project(No.2022JB013)Engineering characteristic team of Sichuan University(No.2020SCUNG122).
文摘The problems of electromagnetic wave(EMW)pollution in X and Ku bands(8–18 GHz)are becoming more and more serious.Therefore,it is urgent to design EMW absorbing materials with high-efficiency such as thin thickness,lightweight,wide bandwidth and strong EMW absorption.Inspired by the biomorph of sea cucumber,Nb_(2)CT_(x) MXene@Co nitrogen-doped carbon nanosheet arrays@carbon fiber aerogels(Nb_(2)CT_(x)@Co-NC@CFA,Nb_(2)CT_(x)=niobium carbide)were constructed by self-assembly,in-situ chemical deposition and subsequent pyrolysis.The carbon fiber aerogel,as the basic skeleton of sea cucumber,forms lightweight three-dimensional interconnected conductive network,enhances the dielectric loss and extends the multiple reflection and absorption paths of EMW.As the tentacles of sea cucumber surface,Nb_(2)CT_(x) MXene and Co nitrogen-doped carbon nanosheet arrays exist rich heterogeneous interfaces,which play an important role in improving EMW polarization loss and optimizing impedance matching.The minimum reflection loss(RLmin)of Nb_(2)CT_(x)@Co-NC@CFA reaches−54.7 dB at 9.84 GHz(2.36 mm)with a low filling ratio of 10 wt.%and the effective absorption bandwidth(EAB)of Nb_(2)CT_(x)@Co-NC@CFA reaches 2.96 GHz(8.48–11.44 GHz)with 2.36 mm and 5.2 GHz(12.8–18 GHz)with 1.6 mm,covering most of X and Ku bands by adjusting thickness.The radar cross section(RCS)value of Nb_(2)CT_(x)@Co-NC@CFA is 26.64 dB·m^(2),which is lower than that of the perfect electrical conductor(PEC),indicating that Nb_(2)CT_(x)@Co-NC@CFA can effectively decrease the probability of the target being detected by the radar detector.This work provides ideas for design and development of EMW absorbing materials with high-efficiency EMW absorption in X and Ku bands.
基金supported by the National Natural Science Foundation of China(Grant Nos.12375057,11947301,and 12047502)the Fundamental Research Funds for the Central UniversitiesChina University of Geosciences(Wuhan)(Grant No.G1323523064)。
文摘When atoms are accelerated in the vacuum,entanglement among atoms will degrade compared with the initial situation before the acceleration.In this study,we propose a novel and interesting view that the lost entanglement can be recovered completely when the high-dimensional spacetime is exploited,in the case that the acceleration is not too large,since the entanglement loss rate caused by the large acceleration is faster than the recovery process.We also calculate the entanglement change caused by the anti-Unruh effect and found that the lost entanglement could just be recovered part by the anti-Unruh effect,and the anti-Unruh effect could only appear for a finite range of acceleration when the interaction time scale is approximately shorter than the reciprocal of the energy gap in two dimensional spacetime.The limit case of zero acceleration is also investigated,which gives an analytical interpretation for the increase or recovery of entanglement.
基金supported by the National Natural Science Foundation of China(Nos.51979133,51769010).
文摘This study aimed to develop a novel edible packaging film for the postharvest preservation of banana based on chitosan(CS)and persimmon peel extract(PPE).Scanning electron microscopy analysis showed that PPE was evenly distributed in the CS matrix and Fourier transform infrared spectroscopy analysis showed that CS and PPE interacted to form hydrogen bonds,demonstrating good compatibility.Simultaneously,the addition of PPE also significantly improved the physical properties and antioxidant activity of the CS film.Among them,the CS film containing 10%PPE(CS-PPE 10)showed the optimal mechanical properties,water vapor barrier properties and oxygen barrier properties.The CS film containing 15%PPE(CS-PPE 15)exhibited the best thermal stability,UV-Vis barrier properties and antioxidant activity.In the experiment on banana preservation,CS-PPE 10 film obtained optimal performance on decreasing senescence spots,weight loss,fruit softening,and cell wall degradation,inhibiting the activities of polyphenol oxidase and cell wall-degrading enzymes and maintaining the content of total soluble sugar and ascorbic acid during the storage period.Consequently,CS-PPE 10 film was expected to be a novel edible packaging material to maintain banana quality and prolong shelf life.
