Revista Mexicana de Física最新文献

{"title":"Obtaining nanoparticles of Cu2O by means of a pulsed discharge of CH3CH2OH-N2","authors":"Marcos C. Gonzalez, P. Reyes, Aaron Gomez, Horacio Martínez, Victor Hugo Castrejon","doi":"10.31349/revmexfis.70.011006","DOIUrl":"https://doi.org/10.31349/revmexfis.70.011006","url":null,"abstract":"CH3CH2OH-N2 plasma mixture was used to synthesize cuprous oxide (Cu2O) micro-particles in a pulsed DC sputtering system, using a ethanol pressure of 1.5 Torr and a current of 400 mA at a frequency of 30 kHz. The plasma mixture was used successfully to obtain the micro-particles of Cu2O using a copper (Cu) target and a stainless steel substrate. The Cu2O products are characterized by the scanning electron microscope (SEM), the results show that the morphology of the Cu2O microparticles have a spherical shape which are randomly distributed on the stainless steel substrate. Raman results show that from the CH3CH2OH-N2 plasma mixture it is possible to obtain one of the Cu oxidation phases which corresponds to Cu2O due to the fact that within the sample analyzed by means of Raman it is possible to observe only the peaks that correspond to the Cu2O phase. The analysis by energy dispersive spectroscopy (EDS) serves to determine the stoichiometric balance present in the substrate, from which the presence of the characteristic peaks of stainless steel was confirmed, along with the characteristic peaks of Cu and O which exhibit an atomic ratio of 2:1 respectively. Atomic force microscopy (AFM) was used to again determine the morphology of the microparticles, finding a spherical morphology. In addition, the value of roughness and grain size was determined, finding values of 20 nm and 45 nm respectively. The images 3-D show the presence of peaks and valleys within the substrate and an non-homogeneous distribution of spherical micro-particles on the surface of the stainless steel.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"20 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139389565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wetting properties of thin films of exfoliated hexagonal boron nitride in different solvents","authors":"S. Acosta, Verónica Pérez Luna, Gregorio Sánchez Balderas, J. M. Hernández Meza, Bernardo Yáñez Soto, M. Quintana","doi":"10.31349/revmexfis.69.041607","DOIUrl":"https://doi.org/10.31349/revmexfis.69.041607","url":null,"abstract":"Hexagonal boron nitride (h-BN) is a 2D material with excellent properties, such as large band gap, high thermal and chemical stability, transparency, and high resistance to oxidation and corrosion. These properties make h-BN a suitable candidate to be used in the development of advanced coatings. However, as for other nanomaterials, tailor and control the properties of h-BN is a fundamental key for their application into several fields. Here, the wetting properties of h-BN when is exfoliated by ultrasonic cavitation in different solvents including isopropyl alcohol (IPA), dioxane (Dx), N-methyl pyrrolidone (NMP) and dimethyl formamide (DMF) were investigated. The wetting properties of the different h-BN materials were determined by measuring the water contact angle (WCA) of h-BN thin films deposited on silicon dioxide, different contact angles were observed for each sample, the different WCA values are explained by the differences in the structure and roughness of the thin film surfaces obtained just by changing the solvent during exfoliation. These surface properties were characterized by optic and transmission electronic microscopy (TEM) as well as atomic force microscopy (AFM).","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139362810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparative study between the addition of nano and micro-particles of Co3O4 on the electrical and microstructural properties of a ceramic system based on SnO2","authors":"M. I Miranda López, M. B. Hernández Hernández, B. S. Vera Barrios, A. Toxqui Teran, J. A. Aguilar Martinez","doi":"10.31349/revmexfis.66.47","DOIUrl":"https://doi.org/10.31349/revmexfis.66.47","url":null,"abstract":"A comparative study between the addition of Co3O4 micro-particles and nano-particles as densifying dopant of a SnO2 based varistor system was conducted. The ceramic composition was (99.9-X) %SnO2–X %Co3O4–0.05 %Cr2O3–0.05 %Nb2O5 where X = 0, 0.5, 1.0, 2.0 and 4.0 mol%. Two particle sizes of Co3O4 were used (~5 µm and ~50 nm). The addition of 0.5 mol% of Co3O4 nano-particles promoted an increase of grain size of sintered samples up to 7.9 µm, that is, the maximum value among all variations.  Characterization techniques such as TGA, DTA, XRD, and Rietveld analysis revealed a decrease of 16 ºC in the formation temperature of Co2SnO4 as well as an increase of 2.6 wt% in the amount of said phase with the use of 4.0 mol% of Co3O4 nano-particles in comparison with micro-particles. Statistical analysis indicated that the addition of nano-particles of Co3O4 yield better repeatability on densification of ceramic samples. Residual porosity also was decreased. Electrical breakdown and non-linear coefficient values correspond to a non-ohmic behavior with potential application on manufacture of high voltage varistors. The findings of this work can be used as a reference for conducting a later study to improve the electrical properties or even to lower the sintering temperature.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129391330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth of a TiO2 nanotubular layer without presence of nanograss in a short time","authors":"M. Luna Cervantes, J. Hernández Torres, L. Zamora Peredo, A. Báez Rodríguez","doi":"10.31349/revmexfis.65.49","DOIUrl":"https://doi.org/10.31349/revmexfis.65.49","url":null,"abstract":"Many studies, focused in TiO2 anodized, uses frequently a NH4F salt concentration from 0.3 – 0.5 wt% and the whole information about how voltage, time and even pH affects to nanotubes morphology, are effective just for these concentration range. It is known, increasing salt concentration, the electrolyte increases their conductivity and anodization speed (oxidation-dissolution) suffer also an increment and for a specifically concentration 1.2wt%, there is no data about morphology repercussions. A TiO2 nanotubular matrix is synthesized, in order to identify the range of time where it is possible to obtain with no presence of nanograss. The anodization process consists of an organic electrolyte of ethylene glycol, deionized water and 1.2 wt% NH4F salts, constant potential of 30 V and a time lapse from 10 to 60 minutes (short time). All anodized samples are rinsed and annealed to 400 °C by 4 hours to obtain an anatase crystalline structure; no samples are cleaned in ultrasonic bath to preserve the nanograss structure. Optical characterization was performed by Raman Spectroscopy to identify the increases in signal intensity, associated with thickness. The morphological characterization was carried out by Scanning Electron Microscopy to verify the presence and density of the nanograss and nanotubes.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132028549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hamiltoniano efectivo de un circuito LC con carga discreta bajo la aproximación semiclásica","authors":"Evaristo MAMANI CARLO, Marcelo CALCINA NOGALES, Diego SANJINÉS CASTEDO","doi":"10.31349/revmexfis.64.456","DOIUrl":"https://doi.org/10.31349/revmexfis.64.456","url":null,"abstract":"Se utiliza un modelo de un circuito LC con carga discreta y una fuente AC de frecuencia w elevada para determinar su hamiltoniano efectivo aplicando la aproximación semiclásica y el método de promediación temporal de Kapitza hasta 1/(w^2). El resultado corresponde al de la propagación de una partícula en una red de enlace fuerte por el mecanismo de hopping bajo la acción simultánea de un campo homogéneo rápidamente oscilante y un campo estático lineal, donde la coordenada de posición de la partícula equivale a la carga eléctrica del condensador en el circuito LC. De manera análoga a resultados previos para el oscilador armónico en la red, en este caso también se encuentra una condición de bifurcación dada por la carga inicial del condensador que determina la aparición súbita de un voltaje DC. Otra predicción relevante es la supresión controlada de la corriente efectiva al elegir los parámetros de la fuente AC.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123810711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shortest path fractal dimension for randomly crumpled thin paper sheets","authors":"H. S. Sánchez Chávez, Leonardo Flores Cano","doi":"10.31349/revmexfis.64.415","DOIUrl":"https://doi.org/10.31349/revmexfis.64.415","url":null,"abstract":"We realized a study of the shortest path fractal dimension  in three dimensions for randomly crumpled paper balls. We took measurements between all possible combinations of pairs of points in crumpled and flat configurations, we found that a correlation between these distances exist, even more, such mean experimental value is dmin=1.2953±0.02 that coincides almost numerically with the very known 3D shortest path fractal dimension for percolation systems reported in computational simulations.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130827572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Síntesis y caracterización electroquímica de recubrimientos de multicapas metal cerámico de W/WN, Ti/TiN y WTiN","authors":"Andrés González Hernández, Martin Flores Martinez, Julio Cesar Caicedo Angulo, William Arnulfo Aperador Chaparro, Ana Beatriz Morales Cepeda","doi":"10.31349/revmexfis.64.368","DOIUrl":"https://doi.org/10.31349/revmexfis.64.368","url":null,"abstract":"Corrosion causes great losses and catastrophic damages in industrial plants and infrastructure, among the methods to reduce it are the coatings. The use of metal-ceramic multilayer coatings to reduce corrosion in steels is a viable option, since they offer several advantages over single-layer coatings, among which, they can be deposited with relatively high thicknesses and are able to dissipate the residual stresses that form during the growth of the thin films, which maintains its adhesion to the substrate. The coatings were deposited by magnetron Sputtering, using Ti and W targets. Two multilayer architectures were designed and deposited, including tungsten nitride (WN) and titanium tungsten nitride (WTiN) coatings with alternated bilayers of Ti/TiN and W/WN, those two deposition sequences of layer were identified as A with more Ti and B layers with higher W content; both consist of a nine-layer deposit process. The structure was studied by X-ray diffraction and the morphology and composition by SEM and EDS respectively. The surface was studied with profilometry and atomic force microscopy. The electrochemical behavior was analyzed in a sodium chloride solution by means of potentiodynamic polarizations and electrochemical impedance spectroscopy (EIS). X-ray diffraction results show the presence of two phases of WN. The grain size of coating A is similar to that obtained in coating B. The morphology of the multilayers showed a mostly smooth surface but with the presence of spherical domes, as well as cracks in both coatings, being more abundant in the coating B. In its cross section, the sequence of multilayers composed of layers of Ti, W, TiN, WTiN and WN is observed, however in some cases the change between the individual layers is not observed and two layers remain as one in the images of MEB. The electrochemical results obtained by potentiodynamic polarization curves showed a shift of the corrosion potential towards more noble values. The corrosion current in coating A with more layers of Ti is lower than coating B and both improve the corrosion resistance of the substrate. This behavior was confirmed in the Nyquist diagram obtained by EIS.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121979438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent progress in confined atoms and molecules: Superintegrability and symmetry breakings","authors":"Eugenio Ley Koo","doi":"10.31349/revmexfis.64.326","DOIUrl":"https://doi.org/10.31349/revmexfis.64.326","url":null,"abstract":"This review article has the antecedents of Jaskolski’s 1996 Physics Report Confined Many-electron Systems , the fifteen chapters on the Theory of Confined Quantum Systems in Vols. 57 and 58 of 2009 Advances in Quantum Chemistry, and the nine chapters of the 2014 Monograph “Electronic Structure of Confined Quantum Atoms and Molecules”. In this contribution the last two sets of reviews are taken as the points of reference to illustrate some advances in several lines of research in the elapsed periods. The recent progress is illustrated on the basis of a selection of references from the literature taking into account the confined quantum systems, the confining environments and their modelings; their properties and processes, emphasizing the changes due to the confinement; the methods of analysis and solutions, their results including confiability and accuracy; as well as applications in other areas. The updated and current works of the Reviewer are also presented. The complementary words in the title apply to the simplest atom in its free configuration and to the harmonic oscillator quantum dot because they admit more exact solutions than the number of their degrees of freedom; and to their many-electron and confined counterparts, due to their additional interactions and changes in boundary conditions.","PeriodicalId":207412,"journal":{"name":"Revista Mexicana de Física","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115879331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}