A simple chemical method was employed to coat carbon nanotubes with a layer of copper. Due to the hydrophobic nature, large surface curvature, small diameter and large aspect ratio, it is difficult to gain continuous ...A simple chemical method was employed to coat carbon nanotubes with a layer of copper. Due to the hydrophobic nature, large surface curvature, small diameter and large aspect ratio, it is difficult to gain continuous electroless plating layer on the surface of carbon nanotubes. In this paper, a series methods (oxidization, sensitization and activation) are used to add active sites before electroless plating, and the adjustment of the traditional composition of copper electroless plating bath and operating condition can decelerate electroless plating rate. The samples before and after coating were analyzed using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that the surface of carbon nanotubes was successfully coated with continuous layer of copper, which lays a good foundation for applying carbon nanotubes in composites.展开更多
Imparting electro-conductive properties to nanocellulose-based products may render them suitable for applications in electronics, optoelectronics, and energy storage devices. In the present work, an electro...Imparting electro-conductive properties to nanocellulose-based products may render them suitable for applications in electronics, optoelectronics, and energy storage devices. In the present work, an electro-conductive nanocrystalline cellulose (NCC) film filled with TiO2-reduced-graphene oxide (TiO2-RGO) was developed. Initially, graphene oxide (GO) was prepared using the modified Hummers method and thereafter photocatalytically reduced using TiO2 as a catalyst. Subsequently, an electro-conductive NCC film was prepared via vacuum filtration with the as-prepared TiO2-RGO nanocomposite as a functional filler. The TiO2-RGO nanocomposite and the NCC/TiO2-RGO film were systematically characterized. The results showed that the obtained TiO2-RGO nanocomposite exhibited reduced oxygen-containing group content and enhanced electro-conductivity as compared with those of GO. Moreover, the NCC flm flled with TiO2-RGO nanocomposite displayed an electro-conductivity of up to 9.3 S/m and improved mechanical properties compared with that of the control. This work could provide a route for producing electro-conductive NCC flms, which may hold signifcant potential as transparent ?exible substrates for future electronic device applications.展开更多
The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied fo...The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied for manufacturing the resid hydrotreating catalysts. The influence of different TiO2 contents and calcination temperatures on specific surface area, pore volume and pore size distribution of complex supports was studied. TEM and SEM were employed to characterize the Al2O3-TiO2 complex supports. Test results revealed that the specific surface area of Al2O3-TiO2 complex supports was the largest at a TiO2 mass fraction of 20%, and when the calcination temperature was in the range between 300 ℃ to 700 ℃, the pore distribution of the complex support was stable. Characterization of the complex support by TEM and SEM demonstrated that TiO2 was homo- geneously distributed in the complex support, which was in favor of carrying active components. The Al2O3-TiO2 complex supports can function as the best catalyst support for resid hydrotreating catalysts.展开更多
A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two te...A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two templates respectively are optically projected onto a photodetector array, then the detected Moiré signals are used to estimate the alignment errors in x and y directions. The experiment result indicates that complex differential Moiré signal is sensitive to relative displacement of the pair of marks than each single Moiré signal, and the alignment resolutions obtained in x and y directions are ±20nm(3σ) and ±24nm(3σ). They can meet the requirement of alignment accuracy for submicron imprint lithography.展开更多
To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bott...To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.展开更多
This multivariate study investigated whether Parental Support, Teacher Support, and Academic Motivation mediate the relationship between Parental Status (i.e., children from single or both parents homes) and Academi...This multivariate study investigated whether Parental Support, Teacher Support, and Academic Motivation mediate the relationship between Parental Status (i.e., children from single or both parents homes) and Academic Performance, The research design used for the study was a cross sectional survey using the quantitative approach. Data set from 250 primary school pupils from the Effutu Municipality were analysed using partial correlation and multiple regression analytical techniques. Among the study findings, that were when the effects of Parental Status were controlled for, Parental Support, Teacher Support, and Academic Motivation still related significantly to Academic Performance. Among the conclusions of the findings are that, whether the child was from a single or both parent home was not important with regard to his or her academic performance but rather it was the quality of support that the child gets from whoever is doing the parenting, teacher support and the child's own academic motivation that were important to determine the child's Academic Performance. The study also found that Parental Support was the best predictor of the pupils' Academic Performance out of the three factors includingTeacher Support and Academic Motivation.展开更多
Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) s...Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM (Deepetching, Electroforming and Microreplicating) and FIB (Focused Ion Beam) techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.展开更多
Nanotechnology currently represents one of the most fascinating human discoveries. With creativity, nanotechnology looks for increasingly smaller spaces in nature to meet the needs and interests of the individuals and...Nanotechnology currently represents one of the most fascinating human discoveries. With creativity, nanotechnology looks for increasingly smaller spaces in nature to meet the needs and interests of the individuals and of the society. Considering that the researches aim to create techniques to move and combine atoms and molecules, a question arises, how will these atoms and molecules behave in the new arrangement. This is the great challenge and this article attempts to bring some benefits to the subiect. It also intends to bring the human sciences, particularly law, to the scenery of this scientific revolution. The lack of regulatory frameworks does not allow humans to search and produce anything without limits. Thus, human rights should be considered an ethical foundation for nanotechnology discoveries, as they represent the "rights" that, at least, humans should have respected.展开更多
At an accelerating development pace, Hicro-Nano Satellite technology has become one of the most ac- tive research topics in the current aerospace field. Its applications have been extended from engineering education a...At an accelerating development pace, Hicro-Nano Satellite technology has become one of the most ac- tive research topics in the current aerospace field. Its applications have been extended from engineering education and technology demonstration into various other fields, such as communication, remote sensing, navigation and scientific experiments just to name a few, In this paper issues raised on Micro/Nano-Satellites in recent news are reviewed and the opportunities and challenges confronting Micro/Nano-Satellites are analyzed. Then the Plicro/nano-Satellites of Na- tional University of Defense Technology, (NUDT) are briefly introduced. Finally, some suggestions on the development of Micro/Nano-Satellites in the future are proposed.展开更多
An economical idea was developed to synthesize fluorescent carbon quantum dots (CQDs) directly fl-om the refluxing extraction of orange pericarp via a hydrothermal technique. Hydrothermal temperatures and times were...An economical idea was developed to synthesize fluorescent carbon quantum dots (CQDs) directly fl-om the refluxing extraction of orange pericarp via a hydrothermal technique. Hydrothermal temperatures and times were adjusted to control the particle sizes and the quantum yields of the obtained CQDs. The as-prepared carbon quantum dots showed narrow particle size distribution, good water solubility, and acceptable fluorescence lifetimes. Due to their high stability, these obtained carbon quantum dots have great application potential in nano-biotechnology. Furthermore, carbon spheres with uniform morphology and size can be easily obtained as the reaction byproducts of this green synthesis process.展开更多
Optical traps use focused laser beams to generate forces on targeted objects ranging in size from nanometers to micrometers. However, for their high coefficients of scattering and absorption, micrometer-sized metallic...Optical traps use focused laser beams to generate forces on targeted objects ranging in size from nanometers to micrometers. However, for their high coefficients of scattering and absorption, micrometer-sized metallic particles were deemed non-trappable in three dimensions using a single beam. This barrier is now removed. We demon- strate, both in theory and experiment, three-dimensional (3D) dynamic all-optical manipulations of micrometer- sized gold particles under high focusing conditions. The force of gravity is found to balance the positive axial optical force exerted on particles in an inverted optical tweezers system to form two trapping positions along the vertical direction. Both theoretical and experimental results confirm that stable 3D manipulations are achievable for these particles regardl for a variety of in-depth ess of beam polarization and wavelength. research requiting metallic particles. The present work opens up new opportunities .展开更多
Enzymes are biological catalysts that can convert substrates into products in biochemical reactions.In 1926,the first enzyme,urease,was determined to be a protein by James B.Sumner who won the Nobel Prize in 1946.Sinc...Enzymes are biological catalysts that can convert substrates into products in biochemical reactions.In 1926,the first enzyme,urease,was determined to be a protein by James B.Sumner who won the Nobel Prize in 1946.Since then,enzymes have been considered to be proteins,which allows them to achieve their high catalytic activity with high specific activity under mild conditions.However,in general,the enzyme activity of proteins is lost after exposure to extremes of p H and high temperature,and proteins are also susceptible to digestion by proteases in the environment,which dramatically hinders their practical applications in展开更多
Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to r...Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to realizing functional plasmonie resonances that can manipulate light at the optical frequencies relies on the creation of conductive metallic structures at the nanoscale with low structural defects. Currently, most plasmonic nanostructures are fabricated either by electron beam lithography (EBL) or by focused ion beam (FIB) milling, which are expensive, complicated and time-consuming. In comparison, the direct laser writing (DLW) technique has demonstrated its high spatial resolution and cost-effectiveness in three-dimensional fabrication of micro/nanostrucmres. Furthermore, the recent breakthroughs in superresolution nanofabrication and parallel writing have significantly advanced the fabrication resolution and throughput of the DLW method and made it one of the promising future nanofabrication technologies with low-cost and scalability. In this review, we provide a comprehensive summary of the state-of-the-art DLW fabrication technology for nanometer scale metallic structures. The fabrication mechanisms, different material choices, fabrication capability, including resolution, conductivity and structure surface smoothness, as well as the characterization methods and achievable devices for different applications are presented. In particular, the development trends of the field and the perspectives for future opportunities and challenges are provided at the end of the review. It has been demonstrated that the quality of the metallic structures fabricated using the DLW method is excellent compared with other methods providing a new and enabling platform for functional nanophotonic device fabrication.展开更多
文摘A simple chemical method was employed to coat carbon nanotubes with a layer of copper. Due to the hydrophobic nature, large surface curvature, small diameter and large aspect ratio, it is difficult to gain continuous electroless plating layer on the surface of carbon nanotubes. In this paper, a series methods (oxidization, sensitization and activation) are used to add active sites before electroless plating, and the adjustment of the traditional composition of copper electroless plating bath and operating condition can decelerate electroless plating rate. The samples before and after coating were analyzed using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that the surface of carbon nanotubes was successfully coated with continuous layer of copper, which lays a good foundation for applying carbon nanotubes in composites.
基金financially supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. LY14C160003, LQ16C160002)the National Natural Science Foundation of China (Grant No.31100442)+2 种基金the Public Projects of Zhejiang Province (Grant No. 2017C31059)Zhejiang Provincial Top Key Academic Discipline of Chemical Engineering and Technology, Zhejiang Open Foundation of the Most Important Subjects (Grant No. 2016KF01)521 Talent Cultivation Program of Zhejiang Sci-Tech University (Grant No. 11110132521310)
文摘Imparting electro-conductive properties to nanocellulose-based products may render them suitable for applications in electronics, optoelectronics, and energy storage devices. In the present work, an electro-conductive nanocrystalline cellulose (NCC) film filled with TiO2-reduced-graphene oxide (TiO2-RGO) was developed. Initially, graphene oxide (GO) was prepared using the modified Hummers method and thereafter photocatalytically reduced using TiO2 as a catalyst. Subsequently, an electro-conductive NCC film was prepared via vacuum filtration with the as-prepared TiO2-RGO nanocomposite as a functional filler. The TiO2-RGO nanocomposite and the NCC/TiO2-RGO film were systematically characterized. The results showed that the obtained TiO2-RGO nanocomposite exhibited reduced oxygen-containing group content and enhanced electro-conductivity as compared with those of GO. Moreover, the NCC flm flled with TiO2-RGO nanocomposite displayed an electro-conductivity of up to 9.3 S/m and improved mechanical properties compared with that of the control. This work could provide a route for producing electro-conductive NCC flms, which may hold signifcant potential as transparent ?exible substrates for future electronic device applications.
文摘The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied for manufacturing the resid hydrotreating catalysts. The influence of different TiO2 contents and calcination temperatures on specific surface area, pore volume and pore size distribution of complex supports was studied. TEM and SEM were employed to characterize the Al2O3-TiO2 complex supports. Test results revealed that the specific surface area of Al2O3-TiO2 complex supports was the largest at a TiO2 mass fraction of 20%, and when the calcination temperature was in the range between 300 ℃ to 700 ℃, the pore distribution of the complex support was stable. Characterization of the complex support by TEM and SEM demonstrated that TiO2 was homo- geneously distributed in the complex support, which was in favor of carrying active components. The Al2O3-TiO2 complex supports can function as the best catalyst support for resid hydrotreating catalysts.
文摘A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two templates respectively are optically projected onto a photodetector array, then the detected Moiré signals are used to estimate the alignment errors in x and y directions. The experiment result indicates that complex differential Moiré signal is sensitive to relative displacement of the pair of marks than each single Moiré signal, and the alignment resolutions obtained in x and y directions are ±20nm(3σ) and ±24nm(3σ). They can meet the requirement of alignment accuracy for submicron imprint lithography.
基金Supported by National Natural Science Foundation of China (No. E05020203) , "863" National Hi-Tech Program(No.2002AA420050) and "973" National Key Basic Research Program ( No. 2003CB716202).
文摘To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.
文摘This multivariate study investigated whether Parental Support, Teacher Support, and Academic Motivation mediate the relationship between Parental Status (i.e., children from single or both parents homes) and Academic Performance, The research design used for the study was a cross sectional survey using the quantitative approach. Data set from 250 primary school pupils from the Effutu Municipality were analysed using partial correlation and multiple regression analytical techniques. Among the study findings, that were when the effects of Parental Status were controlled for, Parental Support, Teacher Support, and Academic Motivation still related significantly to Academic Performance. Among the conclusions of the findings are that, whether the child was from a single or both parent home was not important with regard to his or her academic performance but rather it was the quality of support that the child gets from whoever is doing the parenting, teacher support and the child's own academic motivation that were important to determine the child's Academic Performance. The study also found that Parental Support was the best predictor of the pupils' Academic Performance out of the three factors includingTeacher Support and Academic Motivation.
文摘Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM (Deepetching, Electroforming and Microreplicating) and FIB (Focused Ion Beam) techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.
文摘Nanotechnology currently represents one of the most fascinating human discoveries. With creativity, nanotechnology looks for increasingly smaller spaces in nature to meet the needs and interests of the individuals and of the society. Considering that the researches aim to create techniques to move and combine atoms and molecules, a question arises, how will these atoms and molecules behave in the new arrangement. This is the great challenge and this article attempts to bring some benefits to the subiect. It also intends to bring the human sciences, particularly law, to the scenery of this scientific revolution. The lack of regulatory frameworks does not allow humans to search and produce anything without limits. Thus, human rights should be considered an ethical foundation for nanotechnology discoveries, as they represent the "rights" that, at least, humans should have respected.
文摘At an accelerating development pace, Hicro-Nano Satellite technology has become one of the most ac- tive research topics in the current aerospace field. Its applications have been extended from engineering education and technology demonstration into various other fields, such as communication, remote sensing, navigation and scientific experiments just to name a few, In this paper issues raised on Micro/Nano-Satellites in recent news are reviewed and the opportunities and challenges confronting Micro/Nano-Satellites are analyzed. Then the Plicro/nano-Satellites of Na- tional University of Defense Technology, (NUDT) are briefly introduced. Finally, some suggestions on the development of Micro/Nano-Satellites in the future are proposed.
基金supported by the National Basic Research Program of China(2013CB922102,2011CB935800)the National Natural Science Foundation of China(21071076,51172106,21021062)
文摘An economical idea was developed to synthesize fluorescent carbon quantum dots (CQDs) directly fl-om the refluxing extraction of orange pericarp via a hydrothermal technique. Hydrothermal temperatures and times were adjusted to control the particle sizes and the quantum yields of the obtained CQDs. The as-prepared carbon quantum dots showed narrow particle size distribution, good water solubility, and acceptable fluorescence lifetimes. Due to their high stability, these obtained carbon quantum dots have great application potential in nano-biotechnology. Furthermore, carbon spheres with uniform morphology and size can be easily obtained as the reaction byproducts of this green synthesis process.
基金National Natural Science Foundation of China(NSFC)(91750205,61377052,61422506,61427819,61605117)National Key Basic Research Program of China(973)(2015CB352004)+3 种基金National Key Research and Development Program of China(2016YFC0102401)Leading Talents of Guangdong Province Program(00201505)Natural Science Foundation of Guangdong Province(2016A030312010,2016A030310063)Excellent Young Teacher Program of Guangdong Province(YQ2014151)
文摘Optical traps use focused laser beams to generate forces on targeted objects ranging in size from nanometers to micrometers. However, for their high coefficients of scattering and absorption, micrometer-sized metallic particles were deemed non-trappable in three dimensions using a single beam. This barrier is now removed. We demon- strate, both in theory and experiment, three-dimensional (3D) dynamic all-optical manipulations of micrometer- sized gold particles under high focusing conditions. The force of gravity is found to balance the positive axial optical force exerted on particles in an inverted optical tweezers system to form two trapping positions along the vertical direction. Both theoretical and experimental results confirm that stable 3D manipulations are achievable for these particles regardl for a variety of in-depth ess of beam polarization and wavelength. research requiting metallic particles. The present work opens up new opportunities .
文摘Enzymes are biological catalysts that can convert substrates into products in biochemical reactions.In 1926,the first enzyme,urease,was determined to be a protein by James B.Sumner who won the Nobel Prize in 1946.Since then,enzymes have been considered to be proteins,which allows them to achieve their high catalytic activity with high specific activity under mild conditions.However,in general,the enzyme activity of proteins is lost after exposure to extremes of p H and high temperature,and proteins are also susceptible to digestion by proteases in the environment,which dramatically hinders their practical applications in
基金supported by the Australian Research Council through the Discovery Early Career Researcher Award Scheme(Grant No.DE120100291)the Discovery Project Scheme(Grant No.DP150102972)
文摘Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to realizing functional plasmonie resonances that can manipulate light at the optical frequencies relies on the creation of conductive metallic structures at the nanoscale with low structural defects. Currently, most plasmonic nanostructures are fabricated either by electron beam lithography (EBL) or by focused ion beam (FIB) milling, which are expensive, complicated and time-consuming. In comparison, the direct laser writing (DLW) technique has demonstrated its high spatial resolution and cost-effectiveness in three-dimensional fabrication of micro/nanostrucmres. Furthermore, the recent breakthroughs in superresolution nanofabrication and parallel writing have significantly advanced the fabrication resolution and throughput of the DLW method and made it one of the promising future nanofabrication technologies with low-cost and scalability. In this review, we provide a comprehensive summary of the state-of-the-art DLW fabrication technology for nanometer scale metallic structures. The fabrication mechanisms, different material choices, fabrication capability, including resolution, conductivity and structure surface smoothness, as well as the characterization methods and achievable devices for different applications are presented. In particular, the development trends of the field and the perspectives for future opportunities and challenges are provided at the end of the review. It has been demonstrated that the quality of the metallic structures fabricated using the DLW method is excellent compared with other methods providing a new and enabling platform for functional nanophotonic device fabrication.