Página 1 dos resultados de 13736 itens digitais encontrados em 0.044 segundos

W/O/W multiple emulsions obtained by one-step emulsification method and evaluation of the involved variables

MORAIS, Jacqueline M.; SANTOS, Orlando D. H.; NUNES, Junia R. L.; ZANATTA, Cinthia F.; ROCHA-FILHO, Pedro A.
Fonte: TAYLOR & FRANCIS INC Publicador: TAYLOR & FRANCIS INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
45.93%
The effects of some composition variables on the development of multiple emulsions by one-step method were evaluated and their morphology characterized. The formulations that remained stable during the period of the test were submitted to centrifugation and thermal stress tests. The stability and the morphology of multiple droplets were affected not only by the type and concentration of the surfactants employed, but also by the water/oil ratios used. The results suggest that the formation of multiple droplets could involve a combination of transitional and catastrophic phase inversions. The results provide improved knowledge about the one-step emulsification method, a simplified process to prepare multiple emulsions when compared to the two-steps method.

Comparison of Sorbitol MacConkey Agar and a Two-Step Method Which Utilizes Enzyme-Linked Immunosorbent Assay Toxin Testing and a Chromogenic Agar To Detect and Isolate Enterohemorrhagic Escherichia coli

Novicki, Thomas J.; Daly, Judy A.; Mottice, Susan L.; Carroll, Karen C.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2000 EN
Relevância na Pesquisa
45.93%
Enterohemorrhagic Escherichia coli (EHEC) and specifically serotype O157:H7 are a significant cause of hemorrhagic gastrointestinal disease and the hemolytic uremic syndrome. Methods currently used in clinical microbiology labs, such as sorbitol-MacConkey (SMAC) agar, reliably detect only O157:H7. We have evaluated a two-step method that has the potential to identify and isolate all EHEC serotypes, including serotype O157:H7. This method utilizes a chromogenic selective-differential medium for the isolation of E. coli together with an enzyme-linked immunosorbent assay (ELISA) that detects the Shiga-like toxins Stx1 and Stx2. Both are commercially available and usable in a wide range of clinical microbiology laboratories. Compared to a Vero cell cytotoxic assay, SMAC had sensitivities of 23.5% for the identification of all EHEC serotypes and of 50.0% for the identification of O157:H7 alone. The two-step method had sensitivities of 76.5 and 100%, respectively. The ELISA alone had a sensitivity of 82.4% in the detection of Stx1 and Stx2. The specificity was 100% in all cases. Overall, 14 EHEC isolates were obtained: 8 (58%) O157:H7, 2 (14%) O26, 2 (14%) O111:NM, 1 (7%) O103:H2, and 1 (7%) O121:H19. All but one were isolated during the months of May to September. The two-step method was found to be considerably more expensive than SMAC for both positive and negative samples.

A simple, fast, one-step method for the purification of the skeletal-muscle ryanodine receptor.

Shoshan-Barmatz, V; Zarka, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/07/1992 EN
Relevância na Pesquisa
45.78%
In this paper we describe a simple, fast, one-step method for the purification of the skeletal-muscle ryanodine receptor. The ryanodine receptor from CHAPS-solubilized junctional sarcoplasmic-reticulum membranes was adsorbed to a spermine-agarose column and eluted by 2 mM-spermine. The purified receptor, consisting predominantly of a 450 kDa polypeptide on SDS/PAGE, binds [3H]ryanodine with a specific activity of approximately 300 pmol/mg of protein and with a high affinity (KD = 4.7 +/- 2 nM). The purified receptor appears to retain the pharmacological properties of the receptor in the original membranes. The purification resulted in over 80% recovery of the initial ryanodine-binding sites and about 30-96-fold purification. This simple and fast method is highly reproducible and suitable for purification of small as well as large quantities of ryanodine receptor.

Evolution-Operator-Based Single-Step Method for Image Processing

Sun, Yuhui; Wu, Peiru; Wei, G. W.; Wang, Ge
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.94%
This work proposes an evolution-operator-based single-time-step method for image and signal processing. The key component of the proposed method is a local spectral evolution kernel (LSEK) that analytically integrates a class of evolution partial differential equations (PDEs). From the point of view PDEs, the LSEK provides the analytical solution in a single time step, and is of spectral accuracy, free of instability constraint. From the point of image/signal processing, the LSEK gives rise to a family of lowpass filters. These filters contain controllable time delay and amplitude scaling. The new evolution operator-based method is constructed by pointwise adaptation of anisotropy to the coefficients of the LSEK. The Perona-Malik-type of anisotropic diffusion schemes is incorporated in the LSEK for image denoising. A forward-backward diffusion process is adopted to the LSEK for image deblurring or sharpening. A coupled PDE system is modified for image edge detection. The resulting image edge is utilized for image enhancement. Extensive computer experiments are carried out to demonstrate the performance of the proposed method. The major advantages of the proposed method are its single-step solution and readiness for multidimensional data analysis.

The back-step method—Method for obtaining unbiased population parameter estimates for ordered categorical data

Kjellsson, Maria C.; Jönsson, Siv; Karlsson, Mats O.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em 11/08/2004 EN
Relevância na Pesquisa
45.84%
A significant bias in parameters, estimated with the proportional odds model using the software NONMEM, has been reported. Typically, this bias occurs with ordered categorical data, when most of the observations are found at one extreme of the possible outcomes. The aim of this study was to assess, through simulations, the performance of the Back-Step Method (BSM), a novel approach for obtaining unbiased estimates when the standard approach provides biased estimates. BSM is an iterative method involving sequential simulation-estimation steps. BSM was compared with the standard approach in the analysis of a 4-category ordered variable using the Laplacian method in NONMEM. The bias in parameter estimates and the accuracy of model predictions were determined for the 2 methods on 3 conditions: (1) a nonskewed distribution of the response with low interindividual variability (IIV), (2) a skewed distribution with low IIV, and (3) a skewed distribution with high IIV. An increase in bias with increasing skewness and IIV was shown in parameters estimated using the standard approach in NON-MEM. BSM performed without appreciable bias in the estimates under the 3 conditions, and the model predictions were in good agreement with the original data. Each BSM estimation represents a random sample of the population; hence...

A one-step method to fabricate PLLA scaffolds with deposition of bioactive hydroxyapatite and collagen using ice-based microporogens

Li, Jiashen; Chen, Yun; Mak, Arthur F.T.; Tuan, Rocky S.; Li, Lin; Li, Yi
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.8%
Porous poly(L-lactic acid) (PLLA) scaffolds with bioactive coatings were prepared by a novel one-step method. In this process, ice-based microporogens containing bioactive molecules, such as hydroxyapatite (HA) and collagen, served as both porogens to form the porous structure and vehicles to transfer the bioactive molecules to the inside of PLLA scaffolds in a single step. Based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, the bioactive components were found to be transferred successfully from the porogens to PLLA scaffolds evenly. Osteoblast cells were used to evaluate the cellular behaviors of the composite scaffolds. After 8 days culturing, MTT assay and alkaline phosphatase (ALP) activity results suggested that HA/collagen could improve the interactions between osteoblast cells and the polymeric scaffold.

A Four-Step Method for Optimising the Normal Water Level of Reservoirs Based on a Mathematical Programming Model—A Case Study for the Songyuan Backwater Dam in Jilin Province, China

Sun, Shijun; Yan, Xiaofei; Cui, Peng; Feng, Jiang
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.85%
Determination of the optimal normal water level of reservoirs (RNWL) was investigated, incorporating environmental ecology as a primary consideration. RNWL constitutes a relatively significant eigenvalue of any water conservancy project. In the present study, a four-step method based on a mathematical programming model and suitable for RNWL decision making was developed and applied to the water conservancy project of the Songyuan backwater dam in China. System analysis, correlation analysis, significance testing, principal component analysis, sensitivity analysis, and system optimisation theory are used in the solution process. In this study, various factors that impact the economic viability, engineering characteristics, environmental and urban ecology are considered for holistic optimisation. The study shows that the proposed four-step method may provide a feasible quantitative form of support for RNWL decision making.

What we talk about when we talk about capacitance measured with the voltage-clamp step method

Taylor, Adam L.
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.91%
Capacitance is a fundamental neuronal property. One common way to measure capacitance is to deliver a small voltage-clamp step that is long enough for the clamp current to come to steady state, and then to divide the integrated transient charge by the voltage-clamp step size. In an isopotential neuron, this method is known to measure the total cell capacitance. However, in a cell that is not isopotential, this measures only a fraction of the total capacitance. This has generally been thought of as measuring the capacitance of the “well-clamped” part of the membrane, but the exact meaning of this has been unclear. Here, we show that the capacitance measured in this way is a weighted sum of the total capacitance, where the weight for a given small patch of membrane is determined by the voltage deflection at that patch, as a fraction of the voltage-clamp step size. This quantifies precisely what it means to measure the capacitance of the “well-clamped” part of the neuron. Furthermore, it reveals that the voltage-clamp step method measures a well-defined quantity, one that may be more useful than the total cell capacitance for normalizing conductances measured in voltage-clamp in nonisopotential cells.

A rapid two-step method for isolation of functional primary mouse hepatocytes: cell characterization and asialoglycoprotein receptor based assay development

Severgnini, Mariano; Sherman, Jennifer; Sehgal, Alfica; Jayaprakash, Narayanannair K.; Aubin, Justin; Wang, Gang; Zhang, Ligang; Peng, Chang G.; Yucius, Kristina; Butler, Jim; Fitzgerald, Kevin
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.78%
Primary mouse hepatocytes are an important tool in the biomedical research field for the assessment of hepatocyte function. Several methods for hepatocyte isolation have been published; however, many of these methods require extensive handling and can therefore compromise the viability and function of the isolated cells. Since one advantage of utilizing freshly isolated cells is to maintain an environment in which the cells are more comparable to their in vivo state, it is important to have robust methods that produce cells with high viability, good purity and that function in a similar manner to that in their in vivo state. Here we describe a modified two-step method for the rapid isolation and characterization of mouse primary hepatocytes that results in high yields of viable cells. The asialoglycoprotein receptor (ASGPR), which is one of the most abundant cell surface receptors on hepatocytes, was used to monitor the function of the isolated hepatocytes by demonstrating specific binding of its ligand using a newly developed flow cytometry based ligand-receptor binding assay. Also, an in vitro screening method for siRNA drug candidates was successfully developed utilizing freshly isolated hepatocytes with minimum culture time.

Synthesis of LiFePO₄/C composite as a cathode material for lithium-ion battery by a novel two-step method; Synthesis of LiFePO(4)/C composite as a cathode material for lithium-ion battery by a novel two-step method

Zhang, L.; Xiang, H.; Zhu, X.; Yang, W.; Wang, H.
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
45.98%
In this study, LiFePO4/C is synthesized via a novel two-step method. The first step is the synthesis of nano-sized intermediate FePO4 by a modified sol–gel method. A fast and full combustion procedure is involved to remove carbon and control the size of the intermediate particles. The second step is to prepare LiFePO4/C by combining solid-state reaction with controllable carbon coating. This two-step method is facile to prepare nano-sized LiFePO4 and easy to optimize the carbon content for surface coating. X-ray diffraction shows that the LiFePO4/C composite possesses good crystallinity. Spherical morphology with a diameter of 30–150 nm is observed by scanning electron microscope and transmission electron microscope. Electrochemical measurements indicate that the LiFePO4/C composite exhibits discharge capacities of 162, 144, 126, and 106 mAh g−1 at 0.1, 1, 2, and 5C, respectively. No capacity fading is observed in 50 cycles.; Le Zhang, Hongfa Xiang, Xuefeng Zhu, Weishen Yang, Haihui Wang

Rapid, low-cost, two-step method to screen for urinary schistosomiasis at the district level: the Kilosa experience.

Lengeler, C.; Kilima, P.; Mshinda, H.; Morona, D.; Hatz, C.; Tanner, M.
Fonte: World Health Organization Publicador: World Health Organization
Tipo: Artigo de Revista Científica
Publicado em //1991 EN
Relevância na Pesquisa
45.87%
The operational and diagnostic performance of a two-step method for the cost-effective screening of urinary schistosomiasis was investigated in the Kilosa District of east-central Tanzania. In the first step a simple questionnaire was administered to 15,073 primary schoolchildren by their class teachers over a 4-week period. The answers to the questionnaires had a high negative predictive value for schistosomiasis, and this permitted the safe exclusion of schools where the risk of the disease was low. In the second step, the head-teachers of the 49 high-risk schools and of 26 low-risk schools were instructed on the use of reagent sticks to detect haematuria. Each head-teacher then performed this test on 80 children selected at random in their schools (5750 children were screened within 6 weeks). Crosschecks of the results in 18 schools confirmed the reliability of the head-teachers' testing and their findings were therefore used to prepare an epidemiological map of the district and to arrange for treatment of positive children. This two-step approach relied entirely on the existing school system and permitted screening of a rural district of area 15,000 km2 (population, 350,000) over a 4-month period at a cost of only US$3000.

Pyrosequencing™ : A one-step method for high resolution HLA typing

Ramon, Daniel; Braden, Megan; Adams, Sharon; Marincola, Francesco M; Wang, Lu
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 26/11/2003 EN
Relevância na Pesquisa
45.81%
While the use of high-resolution molecular typing in routine matching of human leukocyte antigens (HLA) is expected to improve unrelated donor selection and transplant outcome, the genetic complexity of HLA still makes the current methodology limited and laborious. Pyrosequencing™ is a gel-free, sequencing-by-synthesis method. In a Pyrosequencing reaction, nucleotide incorporation proceeds sequentially along each DNA template at a given nucleotide dispensation order (NDO) that is programmed into a pyrosequencer. Here we describe the design of a NDO that generates a pyrogram unique for any given allele or combination of alleles. We present examples of unique pyrograms generated from each of two heterozygous HLA templates, which would otherwise remain cis/trans ambiguous using standard sequencing based typing (SBT) method. In addition, we display representative data that demonstrate long read and linear signal generation. These features are prerequisite of high-resolution typing and automated data analysis. In conclusion Pyrosequencing is a one-step method for high resolution DNA typing.

Resolución numérica de las ecuaciones de Navier-Stokes; Numerical solution of the Navier-Stokes equations

Cavada López-Tapia, Adriana
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Trabalho de Conclusão de Curso
SPA
Relevância na Pesquisa
45.81%
RESUMEN: El objetivo fundamental de este proyecto consiste en resolver numéricamente las ecuaciones de Navier-Stokes en su forma incompresible mediante la creación de un código programado con MatLab que permita resolver y estudiar la fenomenología de la mecánica de fluidos. La idea principal es profundizar en la física que hay detrás del proceso de la implementación computacional de un problema, por lo que el código resolverá casos con geometrías sencillas, y la eficiencia del mismo no será una prioridad. Se ha propuesto una discretización espacial mediante el método de volúmenes finitos y se ha utilizado el método de pasos fraccionados para resolver el acoplamiento de la velocidad y la presión. Con el fin de validar el programa se ha utilizado un caso test denominado \driven cavity\ en dos dimensiones, caso muy común en la dinámica de fluidos computacional para validar nuevos códigos que resuelven el movimiento de fluidos. Se han estudiado tres números de Reynolds en régimen laminar, 100, 1000 y 2000. Los resultados obtenidos con el código nuevo son similares a los obtenidos con el software comercial ANSYS Fluent.; ABSTRACT: The main objective of this project is to numerically solve the incompressible Navier-Stokes equations by creating a code programmed with MatLab that allows solving and studying the phenomenology of fluids dynamics. The principal idea is to delve into the physics behind the process of implementing computationally a problem...

On converting any one-step method to a variational integrator of the same order

Patrick, George W.; Spiteri, Raymond J.; Zhang, William; Cuell, Charles
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/03/2009
Relevância na Pesquisa
45.85%
In the formalism of constrained mechanics, such as that which underlies the SHAKE and RATTLE methods of molecular dynamics, we present an algorithm to convert any one-step integration method to a variational integrator of the same order. The one-step method is arbitrary, and the conversion can be automated, resulting in a powerful and flexible approach to the generation of novel variational integrators with arbitrary order.

One-step method to grow Ba0.6K0.4Fe2As2 single crystals without fluxing agent

Wang, Chunlei; Yao, Chao; Wang, Lei; Qi, Yanpeng; Gao, Zhaoshun; Wang, Dongliang; Zhang, Xianping; Ma, Yanwei
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/11/2010
Relevância na Pesquisa
45.8%
Single crystals of Ba0.6K0.4Fe2As2 with excellent quality have been successfully grown without fluxing agent through a simple one-step method for the first time. X-ray diffraction patterns demonstrate that the samples have high crystalline quality and c-axis orientation. The onset transition temperature is up to 38 K with the zero resistivity temperature about 36.7 K. Both the R-T and M-T data show a very sharp superconducting transition with transition width 0.4 K. We also found that the samples possess very large current carrying ability and high upper critical fields, indicating potential applications requiring very high field. The above simple and safe one-step technique of single crystal growth can be effective in other systems of Fe-based superconductors.; Comment: 15 pages, 7 figures

Instability of the finite-difference split-step method on the background of a soliton of the nonlinear Schrodinger equation

Lakoba, T. I.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/08/2012
Relevância na Pesquisa
45.89%
We consider the implementation of the split-step method where the linear part of the nonlinear Schr\"odinger equation is solved using a finite-difference discretization of the spatial derivative. The von Neumann analysis predicts that this method is unconditionally stable on the background of a constant-amplitude plane wave. However, simulations show that the method can become unstable on the background of a soliton. We present an analysis explaining this instability. Both this analysis and the instability itself are substantially different from those of the Fourier split-step method, which computes the spatial derivative by spectral discretization. We also found that the modes responsible for the numerical instability are supported by the sides of the soliton, in contrast to unstable modes of linearized nonlinear wave equations, which (the modes) are supported by the soliton's core.; Comment: 25 pages, 8 figures

On the Dynamic Consistency of the Split Step Method for Classifying the Asymptotic Behaviour of Globally Stable Differential Equations perturbed by State--independent Stochastic terms

Appleby, John A. D.; Cheng, Jian; Rodkina, Alexandra
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/10/2013
Relevância na Pesquisa
45.8%
In this paper we classify the pathwise asymptotic behaviour of the discretisation of a general autonomous scalar differential equation which has a unique and globally stable equilibrium. The underlying continuous equation is subjected to a stochastic perturbation whose intensity is state--independent. In the main result, it is shown that when the split--step--method is applied to the resulting stochastic differential equation, and the stochastic intensity is decreasing, the solutions of the discretised equation inherit the asymptotic behaviour of the continuous equation, regardless of whether the continuous equation has stable, bounded but unstable, or unbounded solutions, provided the step size is chosen sufficiently small.; Comment: 34 pages

A high-order positivity-preserving single-stage single-step method for the ideal magnetohydrodynamic equations

Christlieb, Andrew J.; Feng, Xiao; Seal, David C.; Tang, Qi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/09/2015
Relevância na Pesquisa
45.93%
We propose a high-order finite difference weighted ENO (WENO) method for the ideal magnetohydrodynamics (MHD) equations. The proposed method is single-stage (i.e. it has no internal stages to store), single-step (i.e. it has no time history that needs to be stored), maintains a discrete divergence-free condition on the magnetic field, and has the capacity to preserve the positivity of the density and pressure. To accomplish this, we use a Taylor discretization of the Picard integral formulation (PIF) of the finite difference WENO method proposed in [SINUM, 53 (2015), pp. 1833-1856], where the focus is on a high-order discretization of the fluxes (as opposed to the conserved variables). We use constrained transport in order to obtain divergence-free magnetic fields, which means that we simultaneously evolve the magnetohydrodynamic (which has an evolution equation for the magnetic field) and magnetic potential equations alongside each other, and set the magnetic field to be the (discrete) curl of the magnetic potential after each time step. In order to retain a single-stage, single-step method, we develop a novel Lax-Wendroff discretization for the evolution of the magnetic potential, where we start with technology used for Hamilton-Jacobi equations in order to construct a non-oscillatory magnetic field. Positivity preservation is realized by introducing a parameterized flux limiter that considers a linear combination of the high and low-order numerical fluxes. The choice of the free parameter is then given in such a way that the fluxes are limited towards the low-order solver until positivity is attained. We present two and three dimensional numerical results for several standard test problems including a smooth Alfven wave...

Superovulação de novilhas da raça Nelore com diferentes doses de FSH/LH e congelação de embriões pelo método one-step com etilenoglicol; Superovulation of Nelore heifers with different FSH/LH doses and embryo freezing by one-step method with ethylene-glycol

Visintin, José Antonio; Arruda, Rubens Paes de; Madureira, Ed Hoffman; Mizuta, Katia; Celeghini, Eneiva Carla Carvalho; Assumpção, Mayra Elena Ortiz D’Avila; Gusmões, Pedro Paulo Gimenes; Candini, Pedro Henrique
Fonte: Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia Publicador: Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/01/1999 POR
Relevância na Pesquisa
45.97%
Este trabalho teve como objetivo identificar a dose mais eficiente de FSH/LH (300, 400 e 500 UI) no tratamento superovulatório de novilhas da raça Nelore, assim como avaliar o método one-step no processo de congelação de embriões. A variação da resposta superovulatória tem sido muito grande, o que explica o interesse de diversos pesquisadores em encontrar novos hormônios, doses e momentos para realizar a estimulação ovariana. Foram empregadas doses de 300 (n = 20), 400 (n = 21) ou 500 UI (n = 21) de FSH/LH, iniciando-se no décimo dia do ciclo estral, em 8 aplicações decrescentes, durante quatro dias consecutivos. Foi aplicado PGF2alfa concomitante com a quinta subdose de FSH/LH e realizadas duas inseminações artificiais às 12 e às 24 horas após o início dos sintomas de estro. As colheitas dos embriões foram realizadas 6,5 dias após a primeira inseminação artificial. Pelo exame ultra-sonográfico, avaliaram-se os números de folículos no momento da inseminação artificial (15,12; 15,76; e 14,94) e de corpos lúteos (10,68; 11,55; e 10,81) no dia da colheita, encontrando 5,20; 1,81; e 2,76 embriões viáveis, respectivamente, para 300 UI, 400 UI e 500 UI de FSH/LH. O grupo de 300 UI de FSH/LH apresentou os melhores resultados em relação aos embriões viáveis. Dos 106 embriões congelados pelo método one-step em 1...

γ-Fe2O3/ZnO composite particles prepared by a two step chemical soft method

López-Romero,S.; Morales Leal,F.
Fonte: Sociedad Mexicana de Física Publicador: Sociedad Mexicana de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
45.93%
Composite iron oxide-Zinc oxide (γ-Fe2O3/ZnO) was synthesized by two step method: in the first one step γ-Fe2O3 particles were obtained by a cetyltrimethylammonium hydroxide (CTAOH) assisted hydrothermal method at low temperature (60°C). In the second step, the γ-Fe2O3 particles were included in the ZnO particles synthesis, which were obtained by a hexamethylenetetramine (HMTA) assisted hydrothermal method at low temperature (90° C). SEM study of the samples revealed that the γ-Fe2O3/ZnO composites present a compact morphology. The γ-Fe2O3 and ZnO phases were identified by XRD, energy dispersive X-ray analysis (EDX) and analysis of the IR spectrum. The composite exhibit the characteristic emissions of ZnO under UV radiation and ferromagnetic behavior of γ-Fe2O3 under an external magnetic field.