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Demonstration of Covalent Sidewall Functionalization of Single Wall Carbon Nanotubes by NMr Spectroscopy:Side Chain Length Dependence on the Observation of the Sidewall sp^(3)Carbons

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Nano research 2008年第1期1卷 72-88页

作者： Liling Zeng Lawrence B.Alemany Christopher L.Edwards andrew r.barron richard E.Smalley Institute for Nanoscale Science and Technology and Department of Chemistry Rice UniversityHoustonTX 77005USA

Carboxylic acid-functionalized single walled carbon nanotubes(SWNTs)prepared via the reaction of an amino acid,NH2(CH2)nCO2H where n=1(glycine,GLY),5(6-aminohexanoic acid,AHA),10(11-aminoundecanoic acid,AUDA),with fl uorinated single walled carbon nanotubes(F-SWNTs)have been characterized by MAS 13C NMr *** ease of observing the aliphatic CH2 groups and the resolution of the signal are dependent on the length of the amino acid’s aliphatic *** have proposed that where substituent chains are short(making NMr data collection difficult)chemical modification to extend the chain length should alleviate analysis *** this regard,we have investigated the esterifi cation of the carboxylic acid *** amino acid-functionalized SWNTs were esterified with an appropriate alcohol to ensure parity of the overall substituent length,i.e.,GLY-SWNT(C1)+1-dodecanol(C_(12))=DOD-GLY-SWNT(1),AHA-SWNT(C_(5))+1-octanol(C_(8))=OCT-AHA-SWNT(2),and AUDA-SWNT(C_(10))+1-propanol(C_(3))=PrO-AUDA-SWNT(3).The 13C NMr shift for the sp3 nitrogen-substituted carbon atoms of the SWNT sidewall is observed atδ≈75 *** the length of SWNT sidewall functional groups enhances the ability to observe the sidewall sp^(3)*** methylene carbon signal intensity is less attenuated in the dipolar dephasing spectrum of the ester-functionalized SWNTs than their associated amino acid derivatives,suggesting more motional freedom of the side chain in the solid *** confi rmation of the dipolar dephasing spectral effects was assisted by the characterization of the ester of AUDA-SWNT with 1,3-propanediol:PPD-AUDA-SWNT(4).

关键词： Single walled carbon nanotube(SWNT) nuclear magnetic resonance(NMr) esterification amino acid functionalization

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radical Addition of Perfluorinated Alkyl Iodides to Multi- Layered Graphene and Single-Walled Carbon Nanotubes

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Nano research 2010年第2期3卷 138-145页

作者： Christopher E.Hamilton Jay r.Lomeda Zhengzong Sun James M.Tour andrew r.barron richard E.Smalley Institute for Nanoscale Science and Technology Department of Chemistry and Department of Mechanical Engineering and Materials ScienceRice UniversityHoustonTexas 77005USA

A simple one-pot reaction that serves to functionalize graphite nanosheets(graphene)and single-walled carbon nanotubes(SWNTs)with perfluorinated alkyl groups is *** radical addition of 1-iodo-1H,1H,2H,2H-perfluorododecane to ortho-dichlorobenzene suspensions of the carbon nanomaterial is initiated by thermal decomposition of benzoyl ***,UV photolysis of 1-iodo-perfluorodecane serves to functionalize the carbon ***-SWNTs,perfluorododecyl-graphene,and perfluorodecyl-graphene are characterized by infrared(Ir)and raman spectroscopy,X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and atomic force microscopy(AFM).The products show enhanced dispersability in CHCl3 as compared to unfunctionalized starting *** advantage of this one-pot functionalization procedure lies in the use of pristine graphite as starting material thereby avoiding the use of harsh oxidizing conditions.

关键词： Nanotube single-walled carbon nanotube graphene radical addition

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Numerical Solution of Partial Differential Equations in Arbitrary Shaped Domains Using Cartesian Cut-Stencil Finite Difference *** II:Higher-Order Schemes

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Numerical Mathematics(Theory,Methods and Applications) 2022年第3期15卷 819-850页

作者： M.Esmaeilzadeh r.M.barron Department of Mechanical Automotive&Materials EngineeringUniversity of WindsorWindsorOntarioN9B 3P4Canada Department of Mathematics&Statistics University of WindsorWindsorOntarioN9B 3P4Canada Department of Mechanical Engineering South Tehran BranchIslamic Azad UniversityTehranP.C:***Iran

Compact higher-order(HO)schemes for a new finite difference method,referred to as the Cartesian cut-stencil FD method,for the numerical solution of the convection-diffusion equation in complex shaped domains have been addressed in this *** Cartesian cut-stencil FD method,which employs 1-D quadratic transformation functions to map a non-uniform(uncut or cut)physical stencil to a uniform computational stencil,can be combined with compact HO Pad´e-Hermitian formulations to produce HO cut-stencil *** modified partial differential equation technique is used to develop formulas for the local truncation error for the cut-stencil HO *** effect of various HO approximations for Neumann boundary conditions on the solution accuracy and global order of convergence are *** numerical results for second-order and compact HO formulations of the Cartesian cut-stencil FD method have been compared for test problems using the method of manufactured solutions.

关键词： Cartesian cut-stencil finite difference method compact higher-order formulation irregular domain Neumann boundary conditions local truncation error

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Solvent-free microwave-assisted synthesis of tenorite nanoparticle-decorated multi-walled carbon nanotubes

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Journal of Materials Science & Technology 2019年第6期35卷 1121-1127页

作者： Jennifer A. rudd Cathren E. Gowenlock Virginia Gomez Ewa Kazimierska Abdullah M. Al-Enizi Enrico Andreoli andrew r. barron Energy Safety research Institute Swansea University Bay Campus Swansea SA1 8EN UK Chemistry Department College of Sciences KingSaud University Riyadh Saudi Arabia Department of Chemistry Rice University Houston Texas 77005 USA Department of Materials Science and Nanoengineering Rice University Houston Texas 77005 USA

Copper-decorated carbon nanotubes(CNTs) have important applications as precursors for ultraconductive copper wires. Tenorite-decorated CNTs(CuO-CNTs) are ideal candidates and are currently developed using laborious processes. For this reason, we have developed a facile and scalable method for the synthesis of CuO-CNTs from copper acetate. It was found that the optimal loading of copper acetate onto the CNTs was 23.1 wt% and that three 1-minute microwave treatments were sufficient for the decomposition of copper acetate to copper oxide. The loading of copper oxide onto the nanotubes was confirmed using X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. The materials were characterised using X-ray diffraction and scanning electron microscopy.

关键词： Microwave-assisted synthesis Multi-walled carbon nanotubes Tenorite Nanoparticle

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A comparison of honeybee (Apis mellifera) queen, worker and drone larvae by rNA-Seq

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Insect Science 2019年第3期26卷 499-509页

作者： Xu-Jiang He Wu-Jun Jiang Mi Zhou andrew B. barron Zhi-Jiang Zeng Honeybee research Institute Jiangxi Agricultural University Nanchang China Biomarker Technologies Co. Ltd. Beijing China 2Department of Biological Sciences Macquarie University North Ryde NSW Australia

Honeybees (Apis mellifera) have haplodiploid sex determination: males develop from unfertilized eggs and females develop from fertilized ones. The differences in larval food also determine the development of females. Here we compared the total somatic gene expression profiles of 2-day and 4-day-old drone, queen and worker larvae by rNASeq. The results from a co-expression network analysis on all expressed genes showed that 2-day-old drone and worker larvae were closer in gene expression profiles than 2-day-old queen larvae. This indicated that for young larvae (2-day-old) environmental factors such as larval diet have a greater effect on gene expression profiles than ploidy or sex determination. Drones had the most distinct gene expression profiles at the 4-day larval stage, suggesting that haploidy, or sex dramatically affects the gene expression of honeybee larvae. Drone larvae showed fewer differences in gene expression profiles at the 2-day and 4-day time points than the worker and queen larval comparisons (598 against 1190 and 1181), suggesting a different pattern of gene expression regulation during the larval development of haploid males compared to diploid females. This study indicates that early in development the queen caste has the most distinct gene expression profile, perhaps reflecting the very rapid growth and morphological specialization of this caste compared to workers and drones. Later in development the haploid male drones have the most distinct gene expression profile, perhaps reflecting the influence of ploidy or sex determination on gene expression.

关键词： caste differentiation envir on mental factors gene expression haploid and diploid honeybees larval development

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A New Phasor Estimator for PMU Applications:P Class and M Class

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Journal of Modern Power Systems and Clean Energy 2020年第1期8卷 55-66页

作者： Jose r.razo-Hernandez Arturo Mejia-barron David Granados-Lieberman Martin Valtierra-rodriguez Jose F.Gomez-Aguilar ENAP-research Group Facultad de IngenieríaUniversidad Autónoma de Querétaro(UAQ)San CayetanoC.P.76807México ENAP-research Group Departamento de Ingeniería ElectromecánicaInstituto Tecnológico Superior de Irapuato(ITESI)Colonia El CopalC.P.36821México CONACyT-Centro Nacional de Investigación y Desarrollo Tecnológico(CENIDET) Tecnológico Nacional de MéxicoInterior Internado Palmira S/NCol.PalmiraC.P.62490México

Phasor measurement units(PMUs)are fundamental tools in the applications of modern power systems,where synchronized phasor estimations are *** accuracy and dynamic performance requirements for phasor,frequency,and rate of change of frequency(rOCOF)estimations are established in the IEEE Std.C37.118.1-2011 along with the IEEE Std.C37.118.1 a-2014,where two PMU performances are suggested:P class filters for applications requiring fast response and M class filters for applications requiring high rejection to aliased *** this paper,a methodology to design new phasor estimators that satisfy the P class and M class requirements in PMUs is *** proposed methodology is based on finite impulse response filters,brick-wall filters,and complex filter design concepts,where frequency range,time performance,harmonic rejection and out-of-band interference requirements are considered in its design.A comparative analysis using the reference model given by the IEEE Std.C37.118.1 is *** results show the effectiveness of the phasor estimators under steady-state and dynamic conditions according to the PMU standard,making them suitable tools for applications in power systems.

关键词： Brick-wall filter complex filter IEEE Std.C37.118.1 M class P class phasor measurement unit(PMU) phasor estimator

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Updating digital elevation models via change detection and fusion of human and remote sensor data in urban environments

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International Journal of Digital Earth 2015年第2期8卷 153-171页

作者： Carolin Klonner Christopher.barron Pascal Neis Bernhard Hofle Department of Geography University of HeidelbergHeidelbergGermany

OpenStreetMap(OSM)currently represents the most popular project of Volunteered Geographic Information(VGI):geodata are collected by common people and made available for public *** Laser Scanning(ALS)enables the acquisition of high-resolution digital elevation models that are used for many *** study combines the advantages of both ALS and OSM,offering a promising new approach that enhances data quality and allows change detection:the mainly up-to-date 2D data of OSM can be combined with the high-resolution–but rarely updated–elevation information provided by *** case study investigates building objects of OSM and ALS data of the city of Bregenz,*** quality of OSM is discerned by the comparison of building footprints using different true positive definitions(*** area).High quality of OSM data is revealed,yet also limitations of each method with respect to heterogeneous regions and building outlines are *** the first time,an up-to-date Digital Surface Model(DSM)combining 2D OSM and ALS data is achieved.A multitude of applications such as flood simulations and solar potential assessments can directly benefit from this data combination,since their value and reliability strongly depend on an up-to-date DSM.

关键词： OpenStreetMap airborne laser scanning change detection 3D modelling up-to-date digital surface models

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Chromium Adsorption in Different Mineralogical Fractions from Subtropical Soils

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Pedosphere 2017年第1期27卷 106-111页

作者： Jovana BAVArESCO Jesse r. FINK Maria Lucia K. rODrIGUES Clesio GIANELLO Vidal barron Jose TOrrENT Department of Soils Federal University of Rio Grande do Sul 91540-000 Porto Alegre Rio Grande do Sul (Brazil) Laboratory of Soils Federal Institute of Parand 85555-000 Palmas Parand (Brazil) Department of research and Laboratory Environmental Protection Foundation of Rio Grande do Sul State 90620-090 Porto AlegreRio Grande do Sul (Brazil) Department of Agronomy University of Cdrdoba C4 Building Campus of Rabanales 14071 C6rdoba (Spain)

Safe application of chromium （Cr）-containing organic industrial wastes to soil requires considering the ability of the soil to adsorb Cr. In this study, the maximum Cr adsorption capacity was assessed for the bulk samples and their clay and iron-free clay fractions of four subtropical soils differing in mineralogy. To this end, the samples were supplied with Cr（Ⅲ） nitrate solutions at pH 4.5 or 5.5. The results of Cr（Ⅲ） adsorption fitted to a Freundlich equation and the adsorption capacity was positively correlated with soil organic matter and iron oxide contents. The clay fractions adsorbed more Cr per unit mass than the bulk soils and the iron-free clay fractions. The Cr（Ⅲ） adsorption capacity increased with increasing soil pH due to more charges on adsorbing surfaces. Our results suggest that the soils rich in organic matter and iron oxides and having a pH above 4.5 are suitable for application of Cr（Ⅲ）-loaded industrial wastes.

关键词： adsorption capacity environmental contamination iron-free clay fractions iron oxides point of zero charge specificsurface area

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Particle image velocimetry evaluation of flow-altering countermeasures for local scour around a submerged circular cylinder

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International Journal of Sediment research 2022年第4期37卷 411-423页

作者： Priscilla Williams ram Balachandar Vesselina roussinova ronald barron Department of Civil and Environmental Engineering University of Windsor Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor Department of Mathematics and Statistics University of Windsor

The effect of scour countermeasures on the mechanism of local scour around a cylinder requires clarification in order to develop design methodology for use in practice. Previous investigations on countermeasure performance, though useful, have not provided adequate measurements to support this understanding. In the present investigation, particle image velocimetry(PIV) measurements were acquired at several streamwise-vertical planes in the flow field surrounding a submerged circular cylinder with a vertical splitter plate and with a rectangular collar(a horizontal base plate). Analysis of the distribution of mean streamwise velocity and reynolds shear stress as well as the scour formation indicated that the splitter plate disrupted shear layer interaction in the wake region, reducing the width of scour downstream of the cylinder by 3%. The collar eliminated scour upstream of the cylinder entirely by providing protection at the sides of the cylinder where the shear stress exceeds the critical bed shear stress, and the streamwise velocity distribution in the region between the cylinder and the channel sidewall indicated that installation of a rectangular collar causes flow separation at a point further upstream on the cylinder surface.

关键词： Scour and erosion Local scour Pier scour Scour countermeasures Hydraulic modelling Particle image velocimetry (PIV)

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Fabrication of Nanoscale Active Plasmonic Elements Using Atomic Force Microscope Tip-Based Nanomachining

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Nanomanufacturing and Metrology 2022年第1期5卷 50-59页

作者： Ciaran barron Silas O'Toole Dominic Zerulla School of Physics University College DublinDublinIreland

Atomic force microscopy(AFM)is a widely adopted imaging and surface analysis technique that provides resolutions on the nanometer *** tip-based nanomachining has recently been adopted for the fabrication of arbitrarily shaped nanoscale structures.A major challenge of using AFM tip-based machining for the sculpting of nanoscale plasmonic structures is the build-up of displaced material along the sides of the *** we apply this nanomechanical machining method to create active plasmonic elements and present the strategy we have been using to avoid the formation of such ***,a number of post-manufacturing treatments that can potentially be used to reduce the amount of debris surrounding the fabricated structures are discussed.

关键词： Nanomechanical machining Nanoscale fabrication Plasmonics Atomic force microscope AFM

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