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Crystallization and Morphology of Gold Thin Films on Unpolished Si（100） Substrates after Furnace and Flame Annealing

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材料科学与工程（中英文版） 2010年第1期4卷 1-10页

作者： luis de los santos v Angel Bustamante D. Lizbet Leon F. Thanos Mitrelias Adrian Ionescu JustinianoQuispe M. Crispin H. W. Barnes Cavendish Laboratory University of Cambridge J. J Thomson .Av. Cambridge CB3 0HE United Kingdom Facultad de Ciencias Fisicas Universidad Nacional Mayor de San Marcos Ap. Postal 14-0149 Peru

A crystallization and surface evolution study of Au thin film on unpolished Si(100) substrates after annealing at different temperatures above the eutectic point of the Au/Si system are reported. Samples were prepared by conventional evaporation of gold in high vacuum (10-7mbar) environment on substrates at room temperature. Thermal treatments were performed by both furnace and flame annealing techniques. After evaporation, some Au crystallizes were textured in the (111) direction. However, most of the thin film was amorphous and gold silicides such as Au7Si and Au3Si were also found. This crystallization can be achieved by furnace annealing or flame annealing in spite of the differences between their cell parameters. Annealing overcomes the mismatch between the cell parameters arranging the Au layers in the (111) direction and forming gold islands on the surface. Crystallization of gold strongly depends on both, the temperature and time of annealing. Epitaxial formation of Au can be easily reached after some minutes in the case of flame annealing. The epitaxial temperature for Au/Si(100) should be around the eutectic (363 oC). Above the eutectic point, the Au layer melt, the melting starts most likely from grain boundaries and from the interface allowing the islands separate even further and change shapes until hexagonal geometries. The mean crystallite diameters grow up to a maximum mean size of around 90 nm. The free activation energy for grain boundary migration above the eutectic temperature is 0.09 ev. Therefore the type of the silicon substrate changes the mechanism of diffusion and growth of crystallites during annealing of the Au/Si system.

关键词：退火工艺薄膜形貌热处理炉硅衬底黄金火焰结晶糙米

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Bacterial and archaeal communities in saline soils from a los Negritos geothermal area in Mexico

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Pedosphere 2023年第2期33卷 312-320页

作者： Joseph GUEvARA-LUNA Mario HERNÁNdeZ-GUZMÁN Nina MONTOYA-CIRIACO Luc deNDOOvEN Marina Olivia FRANCO-HERNÁNdeZ Paulina ESTRADA-de los santos María Soledad vÁSQUEZ-MURRIETA Escuela Nacional de Ciencias Biológicas Instituto Politécnico NacionalCiudad de México 11340(Mexico) Laboratory of Soil Ecology CinvestavMexico City 07360(Mexico) Centro Tlaxcala de Biología de la Conducta Universidad Autónoma de Tlaxcala.Carretera Federal Tlaxcala-Puebla km.1.5Tlaxcala 90070(Mexico) Unidad Profesional Interdisciplinaria de Biotecnología Instituto Politécnico NacionalCiudad de México 07340(Mexico)

In recent years,there has been a growing need to understand how salinity affects microbial communities in agricultural *** and bacterial community diversities and structures were investigated by high-throughput sequencing analysis of their 16S rRNA in two arable soils with low electrical conductivity(EC)(2.3 and 2.6 dS m^(-1))and a saline soil(EC=17.6 dS m^(-1)).The dominant bacterial phyla in the soils were Proteobacteria(relative abundance(RA)=46.2%),followed by Acidobacteria(RA=13.1%)and Actinobacteria(RA=10.0%),whereas Serratia(RA=6.0%)and Bacillus(RA=4.0%)were the dominant bacterial *** Nitrososphaera(53.5%)was the dominant archaeal phylotype in the arable soils,whereas Nitrosopumilus(RA=0.4%)dominated in the saline *** archaeal and bacterial community structures were different between the soils and significantly correlated with soil sand,arsenic,barium,and antimony contents,but not with soil salinity.

关键词： agricultural soil compositional approach microbial community mud volcano soil salinity soluble anion

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Physical and chemical characterization of sediments from an Andean river exposed to mining and agricultural activities: The Moquegua River, Peru

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International Journal of Sediment Research 2022年第6期37卷 780-793页

作者： luis de los santos valladares Juan luis Ccamapaza Renato Arturo valencia-Bedregal luis Enrique Borja-Castro Jose velazquez-Garcia dehiwalage Harshani Nimalika Perera Adrian Ionescu David Arvidsson Eustace Peregrine Barnes Peter Newton Hugo Lepage Patrick Byrne Angel Guillermo Bustamante Dominguez Crispin H.W.Barnes Cavendish Laboratory Department of Physics University of Cambridge Escuela Acad emico Profesional de Ingeniería Ambiental Universidad Nacional de Moquegua Provincia de Mariscal Nieto Laboratorio de Cer amicos y Nanomateriales Facultad de Ciencias Físicas Universidad Nacional Mayor de San Marcos School of Biological and Environmental Science Liverpool John Moores University

This study presents an analysis of sediments in an Andean river impacted by both natural conditions and anthropogenic activities. Fifty samples were collected from selected sites throughout the Moquegua River drainage basin, and Tambo River headwaters at Pasto Grande, in Peru, and analysed with X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy and thermogravimetric analysis. Si, Ca, Al, Fe, and O, common constituents of soils, were dominant, along with K, N, and P. The latter originating as primary macronutrients or chemical residuals from fertilizers used in agriculture. Higher concentrations of macronutrients and organic components were found in agricultural and urban areas, respectively. Arsenic minerals were also detected, which occur naturally, but possibly at levels augmented by anthropogenic activity. The application of cluster analysis revealed clustering between arsenic, arsenolite, and potassium but no significant geospatial correlation between sample sites in the drainage basin.

关键词： Andean river Moquegua river Sediments Fourier-transform infrared spectroscopy TG-DTG/DTA Clustering analysis

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Arsenic and chromium resistance mechanisms in the Micrococcus luteus group

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Pedosphere 2023年第4期33卷 600-611页

作者： Ivan ARROYO-HERRERA Brenda ROMÁN-PONCE Rafael BUSTAMANTE-BRITO Joseph GUEvARA-LUNA Erika Yanet TAPIA-GARCÍA violeta LARIOS-SERRATO Nannan ZHANG Paulina ESTRADA-de los santos En Tao WANG María Soledad vÁSQUEZ-MURRIETA Escuela Nacional de Ciencias Biológicas Instituto Politécnico NacionalCiudad de México 11340(Mexico) Universidad Politécnica del Estado de Morelos Jiutepec 62550(Mexico) Centro de Ciencias Genómicas Universidad Autónoma de MéxicoCuernavaca 62210(Mexico) CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilisation&Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province Chengdu Institute of BiologyChinese Academy of SciencesChengdu 610041(China)

High arsenic(As)and chromium(Cr)concentrations are currently receiving attention because of their negative effects on the environment and human *** inhabiting contaminated environments have developed resistance mechanisms against the toxicity of these ***,members of the bacterial genus Micrococcus have been isolated from different toxic metal-contaminated environments;however,knowledge concerning its resistance mechanisms to As and Cr toxicity remains *** luteus strains(An24,Mh,NE2TL6,and NE2TTS4)were isolated from the endosphere and soil of two heavy metal-contaminated sites in Mexico to identify differences in the resistance mechanisms by the *** *** strains were resistant to As(As^(3+)and As^(5+)),chromate,dichromate,cobalt,copper,nickel,and *** analysis indicated that the heavy metal-resistant strains(An24,Mh,NE2TL6,and NE2TTS4)could be assigned to the *** group and had more heavy metal-resistant genes(transporters,chaperones,and enzymes)compared to reference strains of the *** group,*** NCTC 2665^(T)and Micrococcus endophyticus JCM 16951^(T).The resistant bacteria were able to biotransform As^(3+)and As^(5+)through a carbon source-dependent *** biotransformation of As5+was potentially carried out in the cytoplasm through a thioredoxin-dependent pathway,which may be coupled with biosorption.A qualitative analysis of organic acids(OAs)identified a change in the OA profile of the metal-resistant strains that was As-or *** genomic and phenotypic findings suggest that the four *** group strains evaluated in the current study have developed resistance mechanisms that may enable their survival in contaminated sites.

关键词： arsenophore biosorption genome analysis heavy metal-resistant strain immobilization organic acid pollutant

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Plant Growth-Promoting Traits in Rhizobacteria of Heavy Metal-Resistant Plants and Their Effects on Brassica nigra Seed Germination

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Pedosphere 2017年第3期27卷 511-526页

作者： Brenda ROMN-PONCE Diana Miryel REZA-vZQUEZ Sonia GUTIRREZ-PAREdeS María de Jesús de HARO-CRUZ Jessica MALDONADO-HERNNdeZ Yanely BAHENA-OSORIO Paulina ESTRADA-de los santos En Tao WANG María Soledad vSQUEZ-MURRIETA Instituto Politécnico Nacional Escuela Nacional de Ciencias Biológicas Prolongación Carpio y Plan de Ayala s/n Col.Santo Tomás Del.Miguel Hidalgo Ciudad de México

Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria(PGPR) for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting(PGP) traits, including production of siderophores and indol-3-acetic acid(IAA). Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizobacteria were also resistant to high levels of heavy metals(including As as a metalloid)(up to 480 mmol L(-1)As(v), 24 mmol L(-1)Pb(Ⅱ), 21 mmol L(-1)Cu(Ⅱ), and 4.5 mmol L(-1)Zn(Ⅱ)). Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further *** inoculation of Brassica nigra seeds with Microbacterium sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1,and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L(-1)Zn(Ⅱ). The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals.

关键词：重金属污染土壤植物根际土壤植物生长种子萌发抗性植物植物修复技术 PGPR 甘蓝

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Correlations between corneal and optic nerve head variables in healthy subjects and patients with primary open angle glaucoma

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International Journal of Ophthalmology(English edition) 2015年第6期8卷 1156-1161页

作者： Federico Saenz-Frances luis Janez Lara Borrego-Sanz Clara Berrozpe-villabona Jose Maria Martinez-de-la-Casa Laura Morales-Fernandez Julian Garcia-Sanchez Enrique santos-Bueso Julian Garcia-Feijoo department of Ophthalmology Clinico San Carlos HospitalComplutense University of Madrid Technology of Knowledge Institute Complutense University of Madrid

AIMTo correlate corneal variables (determined using the Pentacam) with optic nerve head (ONH) variables determined using the Heidelberg retina tomograph (HRT) in healthy subjects and patients diagnosed with primary open angle glaucoma (POAG).METHODSMeasurements were made in 75 healthy eyes and 73 eyes with POAG and correlations examined through Pearson correlation coefficients between the two sets of variables in the two subject groups. The corneal variables determined were corneal volume (Cvol), central corneal thickness (CCT), overall corneal thickness (OvCT), the mean thickness of a circular zone centered at the corneal apex of 1 mm radius (zone I) and the mean thickness of several concentric rings, also centered at the apex until the limbus, each of 1 mm width (zones II to vI respectively). The ONH variables were determined using the *** following pairs of variables were correlated in the control group: CCT-disc area (DAr) (-0.48; Pv-height variation contour (HvC) (0.378; P=0.002); Zone v-HvC (0.388, Pve correlation was detected between central and paracentral corneal thickness and optic disc area. In contrast, the POAG patients showed significant negative correlation between central and paracentral corneal thickness and the cup-disc ratio and CSM, and positive correlation between peripheral corneal thickness and HvC.

关键词： glaucoma optic nerve head corneal thickness

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Structural and Magnetic Properties of Monophasic Maghemite (γ-Fe2O3) Nanocrystalline Powder

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Advances in Nanoparticles 2014年第3期3卷 114-121页

作者： Juan Adrián Ramos Guivar Arturo Isaías Martínez Ana Osorio Anaya luis de los santos valladares Lizbet León Félix Angel Bustamante Dominguez Cavendish Laboratory Department of Physics University of Cambridge Cambridge UK Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional Cinvestav Unidad Saltillo Ciudad de México México Ciudad de México México Laboratorio de Cerámicos y Nanomateriales Facultad de Ciencias Físicas Universidad Nacional Mayor de San Marcos Lima Perú Laboratorio de Nanotecnología e Innovación Tecnológica Departamento de Química e Ingeniería Química Universidad Nacional Mayor de San Marcos Lima Perú Núcleo de Física Aplicada Instituto de Física Universidade de Brasília Brasília Brasil

Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.

关键词： Monophasic Nanomaghemite Rietveld Refinement TEM SAED M-H Loops ZFC

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Chemical Solution deposition of YBa2Cu3O7 Films on YSZ （100） Substrates

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Journal of Chemistry and Chemical Engineering 2014年第6期8卷 547-551页

作者： Henry Elías Sanchez Comejo Angel Bustamante Dominguez1 Ana María Osorio luis de los santos valladares José Albino Aguiar Crispin H. W. Barnes Ceramics and Nanomaterials Laboratory Department of Physics Major National University of San Marcos Lima 14-0149 Peru department of Chemistry and Chemical Engineering Major National University of San Marcos Lima 14-0149 Peru Superconductivity and Advanced Materials Laboratory Department of Physics Federal University of Pernambuco Recife50670-901 Brazil Cavendish Laboratory Department of Physics University of Cambridge Cambridge CB3 0HE United Kingdom

We report the epitaxial growth of YBCO (YBa 2 Cu 3 O 7 ) films on YSZ (Yttria-stabilized Zirconia) (100) substrates by chemical solution deposition. The precursor solution was prepared by dissolving stoichiometric amounts of acetates of Y(OOCCH 3 ) 3 ·4H 2 O, Ba(OOCCH 3 ) 2 and Cu(OOCCH 3 )·2H 2 O in an aqueous solution of oxalic acid (H 2 C 2 O 4 ) and following the sol-gel route. This solution was directly dripped onto YSZ (100) substrates with the help of a Fisher pipette. To form the YBCO film, the sample was crystallized by annealing at 860 °C for 12 h in an oxidizing atmosphere. The characterization was performed by XRD (X-ray diffraction) analysis which revealed high intensity (001) reflections and denoted that most of the grains were c-axis oriented. Randomly oriented grains and other phases such as Y 2 BaCuO 5 and CuO were also detected. The superconducting YBCO phase is demonstrated from the susceptibility versus temperature measurements which indicate a superconducting critical temperature ≈ 90 K. In addition, a surface morphology analysis was performed by optical microscopy and atomic force microscopy which revealed an average roughness of 0.2197 μm.

关键词： YBa2Cu3O7 化学溶液沉积 YBCO薄膜 YSZ 氧化钇稳定的氧化锆超导临界温度原子力显微镜 X射线衍射

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dengue Climate variability in Rio de Janeiro City with Cross-Wavelet Transform

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Journal of Environmental Protection 2022年第3期13卷 261-276页

作者： Suellen Araujo Franco dos santos Hugo Abi Karam Augusto José Pereira Filho Jú lio Cesar Barreto da Silva Jose luis Flores Rojas Julio Migue Angeles Suazo Isela Leonor vá squez Panduro Cesar Arturo Sanchez Pe&ntilde a departamento de Meteorologia Instituto de Geoci&ecirc ncias Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Brasil departamento de Ciê ncias Atmosfé ricas Instituto de Astronomia Geofísica e Ci&ecirc ncias Atmosfé ricas Universidade de S&atilde o Paulo (IAG-USP) S&atilde o Paulo Brasil Programa de Pós-Graduaç &atilde o em Ciê ncias Ambientais Universidade Estadual do Rio de Janeiro (UERJ) Rio de Janeiro Brasil Instituto Geofísico do Peru (IGP) Lima Per&uacute Facultad de Ingeniería Forestal y Ambiental. Universidad Nacional Autó noma de Tayacaja Daniel Herná ndez Morillo (UNAT) Pampas Per&uacute Universidad Tecnoló gicadel Perú Faculdad de Engenier&iacute a Industrial Lima Per&uacute Centro de Previs&atilde o do Tempo e Estudos Climá ticos Cachoeira Paulista Brasil Programa de Pó s-Graduaç &atilde o em Computaç &atilde o Aplicada Instituto Nacional de Pesquisas Espaciais (INPE) S&atilde o José dos Campos S&atilde o Paulo SP Brasil

dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesaegypti, such as high-temperature days interlaced with afternoon or nocturnal rainstorms in summer. This work has the objective of investigating the relationships between variabilities of the El Ni?o-South Oscillation (ENSO) and greater epidemics of dengue in Rio de Janeiro city. To accomplish this goal, the analysis and signal decomposition by cross-wavelet transform (WT) was applied to obtain the cross variability associated with variations of power and phase of both signals by characteristic periods and along with the time series. Data considered in the analysis are (the decimal logarithm of normalized value) of the monthly available notifications of dengue worsening, provided by the public health system of Brazil, and the Southern Oscillation Index (SOI) Ni?o 3.4 data, provided by the National Oceanic and Atmospheric Administration (NOAA), in the period 2000-2017. A maximum cross-wavelet power close to 0.45 was obtained for the representative period of 1 year and also to periods between 3 and 4 years, associated with the positive phase of the SOI index (i.e. , La Ni?a) or with a transition to the positive phase. The evolution of the combined variability of SOI and dengue can be expressed by progressive differences in phase along the time, eventually resulting in yielding phases (i.e., La Niña-dengue epidemic).

关键词： dengue Fever Cross-Wavelet Transform Analysis El Niño-Southern Oscillation Index

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Curupira v1.0: Joint Inversion of vES and TEM for Environmental and Mass Movements Studies

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International Journal of Geosciences 2023年第11期14卷 1160-1176页

作者： Cassiano Antonio Bortolozo Jorge Luís Porsani Tristan Pryer Jorge luis Abril Benjumea Fernando Acácio Monteiro dos santos Marco Antonio Couto Jr. Luana Albertani Pampuch Tatiana Sussel Gonçalves Mendes Daniel Metodiev Marcio Augusto Ernesto de Moraes Rodolfo Moreda Mendes Marcio Roberto Magalhães de Andrade CEMAdeN—National Center for Monitoring and Early Warning of Natural Disasters General Coordination of Research and Development S&#227o José dos Campos Brazil Geophysics department Institute of Astronomy Geophysics and Atmospheric Sciences (IAG) University of S&#227o Paulo (USP) S&#227o Paulo Brazil department of Mathematical Sciences University of Bath Bath UK Colombian Geological Service (SGC) Bogotá Colombia Don Luiz Institute (IDL) University of Lisboa Lisboa Portugal CPRM—Brazilian Geological Survey SUREG-BH Belo Horizonte Brazil Institute of Science and Technology S&#227o Paulo State University (Unesp) S&#227o José dos Campos Brazil

An innovative inversion code, named “Curupira v1.0”, has been developed using Matlab to determine the vertical distribution of resistivity beneath the subsoil. The program integrates vertical Electrical Sounding (vES), successful in shallow subsurface exploration and Time Domain Electromagnetic (TEM) techniques, better suited for deeper exploration, both of which are widely employed in geophysical exploration. These methodologies involve calculating subsurface resistivity through appropriate inversion processes. To address the ill-posed nature of inverse problems in geophysics, a joint inversion scheme combining vES and TEM data has been incorporated into Curupira v1.0. The software has been tested on both synthetic and real-world data, the latter of which was acquired from the Parana sedimentary basin which we summarise here. The results indicate that the joint inversion of vES and TEM techniques offers improved recovery of simulated models and demonstrates significant potential for hydrogeological studies.

关键词： vES TEM Joint Inversion CRS—Controlled Random Search Paraná Sedimentary Basin Brazil

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