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Progress in Natural Science:Materials International 2016年第6期26卷 665-670页

作者： A.Concha-Balderrama G.Rojas-George J.Alvarado-Flores H.Esparza-Ponce M.H.Bocanegra-Bernal A.Reyes-Rojas Centro de Investigación en materiales avanzados S.C.(CIMAV) Laboratorio Nacional de NanotecnologíaMiguel de Cervantes 120 Complejo Industrial ChihuahuaCd.de Chihuahua

La0.7Sr0.3Cr0.4Mn0.6O3-δperovskite nanoparticles have been synthetized using an ethylene glycol modified solgel method and impregnated by Cu0.75Ni0.25nanoparticles. The phase transitions and nucleation kinetics were studied by time resolved x-ray diffraction, Rietveld, Raman spectroscopy and high resolution transmission electron microscopy. Findings have shown that, an atomic disorder dominates from room temperature to 400 °C. Nanoparticles with crystal size del had described the whole process, where the existence of two phases was shown before it reached its complete D3d6point group symmetry.

关键词： Perovskite structure Sol-gel method Composite Kinetics Rietveld

“H_(2)-free” demethoxylation of guaiacol in subcritical water using Pt supported on N-doped carbon catalysts:A cost-effective strategy for biomass upgrading

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Journal of Energy Chemistry 2021年第7期30卷 377-385页

作者： Laura Pastor-Pérez Wei Jin Juan J.Villora-Picó Qiang Wang M.Mercedes Pastor-Blas Antonio Sepúlveda-Escribano Tomas R.Reina department of Chemical and Process Engineering University of SurreyGuildford GU27XHUnited Kingdom laboratorio de materiales avanzados Departamento de Química Inorgánica-Instituto Universitario de Materiales de AlicanteUniversidad de AlicanteApartado 99E-03080 AlicanteSpain College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China

"H_(2)-free" HDO is a revolutionary route to circumvent the limitations of H_(2)-fed HDO reactors for biomass *** work demonstrates the viability of this economically appealing route when an adequate catalyst is ***,we have developed a new family of Pt catalysts supported on N-doped activated carbons for the H_(2)-free HDO process of *** N-donors have been used to tune the catalyst’s structural and electronic *** a general trend,the N-promoted samples are more selective towards oxygen-depleted *** best performing material,namely Pt/PANI-AC reached outstanding guaiacol conversion values-ca.75% at 300℃ while displaying reasonable stability for multiple recycling *** advanced performance is ascribed to the modified electronic and acid-base properties which favor guaiacol activation and C-O cleavage,as well as the excellent dispersion of the Pt nano particles.

关键词： Biomass upgrading N-doped carbon Pt HDO Guaiacol H_(2)-free

Microstructural evaluation and nanohardness of an AlCoCuCrFeNiTi high-entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 634-641页

作者： C.D.Gómez-Esparza R.Peréz-Bustamante J.M.Alvarado-Orozco J.Mu?oz-Salda?a R.Martínez-Sánchez J.M.Olivares-Ramírez A.Duarte-Moller Centro de Investigación en materiales avanzados (CIMAV) Laboratorio Nacional de Nanotecnología CONACYT-Corporación Mexicana de Investigación en materiales S.A.de C.V.(COMIMSA) Centro de Ingeniería y desarrollo Industrial Querétaro Campus Centro de Investigación y de Estudios avanzados del IPN Unidad Querétaro Universidad Tecnológica de San Juan del Río Escuela de Ingeniería Civil Industrialy Mecánica Universidad De La Salle Bajío

An AlCoCuCrFeNiTi high-entropy alloy(HEA) was prepared by mechanical alloying and sintering to study the effect of Ti addition to the widely studied AlCoCuCrFeNi system. The structural and microstructural characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The formation of four micrometric phases was detected: a Cu-rich phase with a face-centered cubic(fcc) structure, a body-centered cubic(bcc) solid solution with Cu-rich plate-like precipitates(fcc), an ordered bcc phase, and a tetragonal structure. The XRD patterns corroborate the presence of a mixture of bcc-, fcc-, and tetragonal-structured phases. The Vickers hardness of the alloy under study was more than twice that of the AlCoCuCrFeNi alloy. Nanoindentation tests were performed to evaluate the mechanical response of the individual phases to elucidate the relationship between chemical composition, crystal structure, and mechanical performance of the multiphase microstructure of the AlCoCuCrFeNiTi HEA.

关键词： high-entropy alloys mechanical alloying microstructure nanoindentation

Seasonal variation and chemical composition of particulate matter： A study by XPS, ICP-AES and sequential microanalysis using Raman with SEM/EDS

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Journal of Environmental Sciences 2018年第12期30卷 32-49页

作者： Lucy T.González Francisco E.Longoria-Rodríguez Margarita Sánchez-Domínguez Cesar Leyva-Porras Karim Acuna-Askar Boris I.Kharissov Alejandro Arizpe-Zapata Juan M.Alfaro-Barbosa Universidad Autónoma de Nuevo León Facultad de Ciencias Químicas Laboratorio de Química Analítica AmbientalCódigo Postal 64570MaonterreyN.L.Mexico Centro de Investigación en materiales avanzados SC Unidad MonterreyAlianza Notre 202 Código Postal 66628 Apodaca Nueuo León Mexico Centro de Investigación en materiales avanzados SC Miguel de Cervantes # 120 Código Postal 31109 Chihuahua Chih. Mexico Universidad Autónoma de Nuevo León Facultad de Medicina Laboratorio de Biorremediación AmbientalCódigo Postal 64460 MonterreyN.L. Mexico

During the winter period（January–March 2016）, the total suspended particles（TSP） and particulate matter smaller than 2.5 μm（PM2.5） were characterized by the application of various analytical techniques in four zones of the Metropolitan Area of Monterrey in Mexico. To evaluate the seasonal variation of some elements in the particulate matter, the results of this study were compared with those obtained during the summer season（July–September 2015）. The speciation of the C_（1s） signal by X-ray photoelectron spectroscopy revealed the contribution of aromatic and aliphatic hydrocarbons as the main components in both seasons. Conversely, carboxylic groups associated with biogenic emissions were detected only in winter. The percentages of SO_4^（2-） ions were lower in winter, possibly caused by the decrease in the solar radiation, and relative humidity recorded. The results of the ICP analysis revealed that Fe, Zn and Cu were the most abundant metals in both TSP and PM2.5 in the two seasons. There were significant seasonal variations for concentrations of As, Ni and Zn in the urban area and for Fe, As, Cd, Ni and Zn in the industrial zone. This was attributed to the greater burning of fuels as well as to an increase in vehicular traffic, the effect of thermal inversion and changes in some meteorological parameters. The results of the sequential microanalysis by Raman spectroscopy and SEM/EDS allowed observation of deposits of carbonaceous material on the particles and to perform the speciation of particles rich in Fe and Pb, which helped infer their possible emission sources.

关键词： Seasonal variation Total suspended particles PM2.5 X-ray photoelectron spectroscopy Micro-Raman spectroscopy

TiO<sub>2</sub>Films Synthesis over Polypropylene by Sol-Gel Assisted with Hydrothermal Treatment for the Photocatalytic Propane degradation

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Green and Sustainable Chemistry 2014年第3期4卷 120-132页

作者： Vanessa Guzmán-Velderrain Yudith Ortega López Jesús Salinas Gutiérrez Alejandro López Ortiz Virginia H. Collins-Martínez Centro de Investigación en materiales avanzados S. C. Laboratorio Nacional de Nanotecnología Depto. de Materiales Nanoestructurados Chihuahua México

The present investigation shows experimental results obtained with TiO2 thin films synthesized by the sol-gel method assisted with hydrothermal treatment over polypropylene, using the dip coating technique. Obtained coatings were characterized through SEM, XRD, UV-Vis and the photo- catalytic activity was monitored by GC. According to results, the hydrothermal treatment facilitates the crystallization of the TiO2 anatase phase, which is present in all synthesized films. Crystal size formed from precursor solutions (estimated by the Scherrer’s equation) depends on the time and temperature of the hydrothermal treatment, wherein solution exposed to a higher temperature treatment of 150。C for 1.5 h (H150/1.5) exhibited a larger crystal size compared to those synthesized at 80。C for 1.5 h and 3 h (H80/1.5 and H80/3). Sample H150/1.5 over polypropylene resulted in a uniform and crack free coating. This behavior was attributed to the precursor solution being denser than those synthesized at 80。C. Additionally, the photocatalytic activity of the coatings was evaluated through the degradation of propane. Coating H150/1.5 reached 100% conversion after 3 h of UV light irradiation.

关键词： TiO2 Coating Polypropylene Propane Photodegradation Photocatalysis

Sintering and Wear Behavior of a FeCrCB Hardfacing Alloy Applied by Tape Casting: A Study of Cooling Rate Effect

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Journal of Minerals and Materials Characterization and Engineering 2020年第5期8卷 393-406页

作者： Fernando Valenzuela de la Rosa Roal Torres Sánchez José T. Holguín-Momaca Carlos Domínguez Ríos Alfredo Aguilar Elguezabal Centro de Investigación en materiales avanzados S.C. Laboratorio Nacional de Nanotecnología Chihuahua México

This study presents a simple process to deposit a hardfacing coating on a steel substrate, based on the sintering of metallic powder applied by tape casting (by a slurry of metallic powder suspension onto a steel substrate) thus avoiding the use of traditional welding processes and their variants. The effect of the cooling of hardfacing after the sintering process, by air at room temperature or by quenching in water, was studied. This new method ensures a good metallurgical bonding between the substrate steel and the hardfacing layer and shows mechanical property improvement on coated pieces, similar to those exhibited by hardfacing coatings produced by several kinds of welding processes. The characterization of the hardfacing coatings was made by X-ray diffraction, optical microscopy, scanning electron microscopy, microhardness and wear resistance according to the ASTM G65 standard. The characterization results show that the presented faces are: M7C3, M3C, MC, M2B and M23B6;there are three different phases in the micrograph glass phase, eutectic phase and hard phase with a volumetric fraction of 0.14, 0.20 and 0.66, respectively, for the air cooled and 0.15, 0.16 and 0.69 when quenched in water. The average microhardness value for the parts cooled in air was 832.5 HV and for that cooled in water was 958.9 HV, and the wear resistance was a mass loss of 0.219 and 0.128 g for parts cooled in air and water, respectively. These results show that the hardfacing coating could have twice the hardness and wear resistance than that observed for the boron steel used as a substrate.

关键词： Hardfacing Sintering Cooling Rate Wear Resistance

Synthesis and Characterization of Bimetallic Gold-Silver Core-Shell Nanoparticles: A Green Approach

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Advances in Nanoparticles 2015年第4期4卷 116-121页

作者： A. Calagua H. Alarcon F. Paraguay Juan Rodriguez Facultad de Ciencias Universidad Nacional de Ingenier&iacute a Lima Per&uacute laboratorio Nacional de Nanotecnologí a Centro de Investigaci&oacute n de materiales avanzados Chihuahua M&eacute xico

Bimetallic gold-silver core-shell nanoparticles were prepared by chemical reduction in aqueous solution, following a method that was friendly to the environment, allowing us to use this for medicinal purposes. Gold nanoparticles were synthesized, and silver cations were then reduced on the nanoparticles. Using the optical properties of metallic nanoparticles, surface plasmon resonance was determined by UV-Vis spectroscopy, and the values obtained for gold and silver were approximately 520 nm and 400 nm in wavelength, respectively. The absorption peaks of the surface plasmon band show a clear red-shift due to size effect in the case of the silver surface, and a plasmon coupling effect, in the case of gold. To obtain a better understanding of the coating conditions, high resolution transmission electron microscopy was used. The average hydrodynamic size and the size distribution of the synthesized nanoparticles were obtained by dynamic light scattering. The development of this process, which is benign for the environment, opens the possibility for many applications in the areas of renewable energy, medicine and biology.

关键词： Nanoparticles Bimetallic Core-Shell Gold Silver Au/Ag

Ecofriendly E-Nose Based in PLA and Only 0.3 wt%of CNTs

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Journal of Renewable Materials 2019年第4期7卷 355-363页

作者： Laura Ribba Jonathan Cimadoro Silvia Goyanes Universidad de Buenos Aires Facultad de Ciencias Exactas y NaturalesDepartamento de FísicaLaboratorio de Polímeros y Materiales Compuestos(LP&MC)Instituto de Física de Buenos Aires(IFIBA-CONICET)Ciudad Universitaria(1428)Ciudad Autónoma de Buenos AiresArgentina

In this work,conductive polymer nanocomposites were developed based on a biodegradable and biobased polymer(poly(lactic acid)),with the incorporation of only 0.3 wt%of carbon nanotubes(CNTs)to be used as volatile solvent *** correct dispersion of the nanofiller was achieved thanks to a CNT non-covalent modification with an azo-dye(disperse orange 3)which allowed to reach the percolation for electric conduction in values as low as 0.3 wt%.The chemo-resistive properties of the developed sensors were investigated by exposure to organic vapors(ethanol,tetrahydrofuran and toluene)and water vapor,showing good *** addition,considering the manipulation to which the sensor will be exposed,wear resistance was characterized,finding that the incorporation of CNTs produced an increase in more than a 50%.

关键词： Poly(lactic acid) carbon nanotubes sensor CPC organic solvent vapor DO3

Influence of ZnO nanoparticles on the microstructure of a CoCrFeMoNi matrix via powder metallurgy

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1467-1476页

作者： C.D.Gómez-Esparza A.Duarte-Moller C.López-Díaz de León R.Martínez-Sánchez J.F.Hernández-Paz C.A.Rodríguez-González centro de investigación en materiales avanzados(cimav) laboratorio nacional de nanotecnologíamiguel de cervantes no.120chihuahua 31136chi8.mexico facultad de ingeniería civil mecánica e industrialuniversidad de la salle bajíoav.universidad 602león 37150gto.mexico instituto de ingeniería y tecnología universidad autónoma de ciudad juárez(uacj)av.del charro 450 nortec4.juárez 32310chi8.mexico

In the last decade,extensive research has been carried out on the microstructural behavior of high-entropy alloys(HEA),for which the in-situ formation of nanoparticles has been ***,studies of the incorporation of nanoparticles in HEA have been rarely *** this work,the addition of zinc oxide nanoparticles(ZnO NP)as reinforcement in a CoCrFeMoNi high-entropy alloy matrix,as well as the morphological,structural,and microstructural evolution of composites synthesized via powder metallurgy,were *** electron microscopy and X-ray diffraction analysis were performed in order to study the microstructural and phase characterization of the *** sintering,it was found that the ZnO NP addition(0.5 wt%,1 wt%and 2 wt%)had a significant influence on the microstructure and hardness of the CoCrFeMoNi high-entropy *** bonding among metal particles was promoted with the additions of Zn O NP.A reduction in porosity as a function of ZnO NP content was also *** microhardness results showed that the composite reached its highest reinforcement in bulk samples with 1 wt%ZnO NP(HV 870),which represented a 20%improvement over the unreinforced HEA matrix.

关键词： high-entropy alloy mechanical alloying nanoparticles composites

Effect of Sn on synthesis of nanocrystalline Ti-based alloy with fcc structure

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Transactions of Nonferrous Metals Society of China 2020年第8期30卷 2119-2131页

作者： C.AGUILAR E.PIO A.MEDINA C.PARRA R.MANGALARAJA P.MARTIN I.ALFONSO K.TELLO departamento de Ingeniería Metalúrgica y de materiales Departamento de Física(+)Universidad Técnica Federico Santa MaríaValparaísoChile Instituto de Investigación en Metalurgia y materiales Universidad Michoacana de San Nicolás de HidalgoMoreliaMéxico laboratorio de Cerámicos avanzados y Nanotecnologia Departamento de Ingeniería de MaterialesUniversidad de ConcepciónConcepciónChile Instituto de Investigaciones en materiales Universidad Nacional Autónoma de MéxicoCampus Morelia UNAMMoreliaMéxico

The effect of the amount of Sn on the formation of fcc phase in Ti-13 Ta-x Sn(x=3,6,9 and 12,at.%)alloys was *** alloys were synthesized by mechanical alloying using a planetary mill,jar and balls of stabilized *** Rietveld refinement,it was found that the obtained fcc phase has crystallite size smaller than 10 nm and microstrain larger than *** conditions are required to form an fcc phase in Ti-based *** all samples,the microstructure of the fcc phase consists of equiaxial crystallites with sizes smaller than 10 *** largest presence of fcc phase in the studied Ti alloy was found with 6 at.%Sn,because this alloy exhibits the largest microstrain(1.5×10-2)and crystallite size of 6.5 *** data reveal that a solid solution and an amorphous phase were formed during *** necessary conditions to promote the formation of solid solution and amorphous phases were determined using thermodynamic *** the amount of Sn increases,the energy required to form an amorphous phase varies from approximately 10 to approximately-5 k J/mol for 3 and 12 at.%Sn,*** thermodynamic calculations are in agreement with XRD patterns analysis and HRTEM results.

关键词： Ti-based alloy phase transformation fcc phase Rietveld analysis mechanical alloying