Electronics over flexible substrates offer advantages of flexibility, portability and low cost, and promising applications in the areas of energy, information, defense science and medical service. In recent years, tre...Electronics over flexible substrates offer advantages of flexibility, portability and low cost, and promising applications in the areas of energy, information, defense science and medical service. In recent years, tremendous progress has been witnessed in the development of flexible wearable devices that can be potentially massively deployed. Of particular interest are intelligent wearable devices, such as sensors and storage cells, which can be integrated by flexible magnetoelectronic devices based on magnetic thin films. To examine this further, the magnetic properties of FeNi thin films with different thicknesses grown on flexible graphene substrate are investigated at room temperature. The coercivity increases with increasing thicknesses of FeNi thin film, which can be attributed to the increase of grain size and decrease of surface roughness. Moreover, the thickness modulated magnetic property shows a magnetic anisotropy shift increase with varying thicknesses of FeNi thin film by using measurements based on ferromagnetic resonance, which further enhances the resonance frequency. In addition, the resonance peak is quite stable after bending it for ten cycles. The result is promising for the future design of flexible magnetoelectronic devices.展开更多
Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with...Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).展开更多
The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging.It is of practical and fundamental importance...The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging.It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies.However,the underlying surface interaction mechanisms of scalants(e.g.,calcite)with various substrates are still not fully understood.In this work,the colloidal probe atomic force microscopy(AFM)technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates,including carbon steel(CR1018),low alloy steel(4140),stainless steel(SS304)and tungsten carbide,under different water chemistries(i.e.,salinity and pH).Measured force profiles revealed that the attractive van der Waals(VDW)interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces,while the repulsive electric double layer(EDL)interactions could inhibit the attachment behaviors.High salinity and acidic p H conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior.The adhesion of calcite particles with CR1018 and4140 substrates was much stronger than that with SS304 and tungsten carbide substrates.The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide,which agreed with surface force measurement results.Besides,high salinity and acidic p H can significantly enhance the scaling phenomena.This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable antiscaling materials in petroleum industries.展开更多
Near-field radiative heat transfer(NFRHT)has the potential to exceed the blackbody limit by several orders of magnitude,offering significant opportunities for energy harvesting.In this study,we have examined the NFRHT...Near-field radiative heat transfer(NFRHT)has the potential to exceed the blackbody limit by several orders of magnitude,offering significant opportunities for energy harvesting.In this study,we have examined the NFRHT between two borophene sheets through the calculation of heat transfer coefficient(HTC).Due to the tunneling of evanescent waves,borophene sheet allows for enhanced heat flux and adjustable NFRHT by varying its electron density and electron relaxation time.Additionally,the near field coupling is further examined when the borophene is deposited on dielectric or lossy substrates.The maximum HTC is closely related to the real part of the dielectric substrate.As a case study,the HTCs on the lossy substrate of MoO_(3),ZnSe,and SiC are calculated for comparisons.Our results indicate that MoO_(3)is the optimal substrate to get the enhanced energy transfer coefficient.It results in a remarkable value of 1737 times higher than the blackbody limit owing to the enhanced photon tunneling probability.Thus,our study reveals the effect of substrate on the HTC between borophene sheets and provides a theoretical guidance for the design of near-field thermal radiation devices.展开更多
建立了一种在温和条件下,用可见光催化合成一系列3,4-二氢异喹啉-1(2H)-酮及其衍生物的方法。该方法在室温条件下,以2-烯丙基-N-甲氧基苯甲酰胺为模板底物,以碘化钾作为光催化剂,25 W 460 nm的蓝色LED灯照射下,合成一系列3,4-二氢异喹啉...建立了一种在温和条件下,用可见光催化合成一系列3,4-二氢异喹啉-1(2H)-酮及其衍生物的方法。该方法在室温条件下,以2-烯丙基-N-甲氧基苯甲酰胺为模板底物,以碘化钾作为光催化剂,25 W 460 nm的蓝色LED灯照射下,合成一系列3,4-二氢异喹啉-1(2H)-酮衍生物,最高产率可达到83%。该合成路径具有底物适用范围广、经济实用等特点,为3,4-二氢异喹啉-1(2H)-酮衍生物合成提供了一种经济简便的方法。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 51901163 and 12104171)the Fundamental Research Funds for the Central Universities (Grant No. 2021XXJS025)the Natural Science Foundation of Hubei Province (Grants No. 2024AFB888)。
文摘Electronics over flexible substrates offer advantages of flexibility, portability and low cost, and promising applications in the areas of energy, information, defense science and medical service. In recent years, tremendous progress has been witnessed in the development of flexible wearable devices that can be potentially massively deployed. Of particular interest are intelligent wearable devices, such as sensors and storage cells, which can be integrated by flexible magnetoelectronic devices based on magnetic thin films. To examine this further, the magnetic properties of FeNi thin films with different thicknesses grown on flexible graphene substrate are investigated at room temperature. The coercivity increases with increasing thicknesses of FeNi thin film, which can be attributed to the increase of grain size and decrease of surface roughness. Moreover, the thickness modulated magnetic property shows a magnetic anisotropy shift increase with varying thicknesses of FeNi thin film by using measurements based on ferromagnetic resonance, which further enhances the resonance frequency. In addition, the resonance peak is quite stable after bending it for ten cycles. The result is promising for the future design of flexible magnetoelectronic devices.
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park (Project HZQBKCZYB-2020030)National Key R&D Program of China (Project 2017YFA0204403)+2 种基金the National Natural Science Foundation of China (Project 51590892)the Major Program of Changsha Science and Technology (Project kh2003023)the Innovation and Technology Commission of HKSAR through Hong Kong Branch of National Precious Metals Material Engineering Research Centre,and the City University of Hong Kong (Project 9667207)。
文摘Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).
基金support from Science Foundation of China University of Petroleum,Beijing (No.2462023QNXZ018)the Natural Sciences and Engineering Research Council of Canada (NSERC)+2 种基金Canada Foundation for Innovation (CFI)the Research Capacity Program (RCP)of Albertathe Canada Research Chairs Program。
文摘The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging.It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies.However,the underlying surface interaction mechanisms of scalants(e.g.,calcite)with various substrates are still not fully understood.In this work,the colloidal probe atomic force microscopy(AFM)technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates,including carbon steel(CR1018),low alloy steel(4140),stainless steel(SS304)and tungsten carbide,under different water chemistries(i.e.,salinity and pH).Measured force profiles revealed that the attractive van der Waals(VDW)interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces,while the repulsive electric double layer(EDL)interactions could inhibit the attachment behaviors.High salinity and acidic p H conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior.The adhesion of calcite particles with CR1018 and4140 substrates was much stronger than that with SS304 and tungsten carbide substrates.The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide,which agreed with surface force measurement results.Besides,high salinity and acidic p H can significantly enhance the scaling phenomena.This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable antiscaling materials in petroleum industries.
基金Project supported by the Natural Science Foundation of Henan Province,China(Grant No.232102231023)。
文摘Near-field radiative heat transfer(NFRHT)has the potential to exceed the blackbody limit by several orders of magnitude,offering significant opportunities for energy harvesting.In this study,we have examined the NFRHT between two borophene sheets through the calculation of heat transfer coefficient(HTC).Due to the tunneling of evanescent waves,borophene sheet allows for enhanced heat flux and adjustable NFRHT by varying its electron density and electron relaxation time.Additionally,the near field coupling is further examined when the borophene is deposited on dielectric or lossy substrates.The maximum HTC is closely related to the real part of the dielectric substrate.As a case study,the HTCs on the lossy substrate of MoO_(3),ZnSe,and SiC are calculated for comparisons.Our results indicate that MoO_(3)is the optimal substrate to get the enhanced energy transfer coefficient.It results in a remarkable value of 1737 times higher than the blackbody limit owing to the enhanced photon tunneling probability.Thus,our study reveals the effect of substrate on the HTC between borophene sheets and provides a theoretical guidance for the design of near-field thermal radiation devices.
文摘建立了一种在温和条件下,用可见光催化合成一系列3,4-二氢异喹啉-1(2H)-酮及其衍生物的方法。该方法在室温条件下,以2-烯丙基-N-甲氧基苯甲酰胺为模板底物,以碘化钾作为光催化剂,25 W 460 nm的蓝色LED灯照射下,合成一系列3,4-二氢异喹啉-1(2H)-酮衍生物,最高产率可达到83%。该合成路径具有底物适用范围广、经济实用等特点,为3,4-二氢异喹啉-1(2H)-酮衍生物合成提供了一种经济简便的方法。
