Magnetic relaxation and magnetization field dependence measurements in La0.5Ca0.5MnO3

We reported a systematic change in the average magnetic relaxation rate, after the application and removal of a 5 T magnetic field, in a polycrystalline sample of La0.5Ca0.5MnO3. Magnetic relaxation measurements and magnetization versus field curves were taken from 10 K to 160 K. The long time behavior of the relaxation curves was approximately logarithmic in all cases. Keywords: Charge Ordering, Relaxation, Magnetic measurementsComment: 2 figures, accepted to be presented in the International Conference on Magnetism 2000 in Recife, also submitted to Journal of Magnetism and Magnetic Material

Metal Nitride Diffusion Barriers for Copper Interconnects

Advancements in the semiconductor industry require new materials with improved performance. With the introduction of copper as the interconnect material for integrated circuits, efficient diffusion barriers are required to prevent the diffusion of copper into silicon, which is primarily through grain boundaries. This dissertation reports the processing of high quality stoichiometric thin films of TiN, TaN and HfN, and studies their Cu diffusion barrier properties. Epitaxial metastable cubic TaN (B1-NaCl) thin films were grown on Si(001) using an ultra-thin TiN (B1-NaCl) seed layer which was as thin as 1 nm. The TiN/TaN stacks were deposited by Pulsed Laser Deposition (PLD), with the TiN thickness systematically reduced from 15 to 1 nm. Microstructural studies included X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM (HRTEM). Preliminary Cu diffusion experiments showed that the TiN seed layer thickness had little or no obvious effect on the overall microstructure and the diffusion barrier properties of the TaN/TiN stacks. Epitaxial and highly textured cubic HfN (B1-NaCl) thin films (~100 nm) were deposited on MgO(001) and Si(001) using PLD. Low resistivities (~40 mu omega-cm) were measured with a four point probe (FPP). Microstructural characterizations included XRD, TEM, and HRTEM. Preliminary Cu diffusion tests demonstrated good diffusion barrier properties, suggesting that HfN is a promising candidate for Cu diffusion barriers. Cubic HfN (B1-NaCl) thin films were grown epitaxially on Si(001) substrates by using a TiN (B1-NaCl) buffer layer as thin as ~10 nm. The HfN/TiN stacks were deposited by PLD with an overall thickness less than 60 nm. Detailed microstructural characterizations included XRD, TEM, and HRTEM. The electrical resistivity measured by FPP was as low as 70 mu omega-cm. Preliminary copper diffusion tests showed good diffusion barrier properties with a diffusion depth of 2~3 nm after vacuum annealing at 500 degrees C for 30 minutes. Additional samples with Cu deposited on top of the cubic HfN/TiN/Si(001) were vacuum annealed at 500 degrees C, 600 degrees C and 650 degrees C for 30 minutes. The diffusivity of copper in the epitaxial stack was investigated using HRTEM. The measured diffusion depths, 2 Dt , were 3, 4 and 5 nm at 500 degrees C, 600 degrees C and 650 degrees C respectively. Finally, the diffusivity of Cu into epitaxial HfN was determined to be D=D0 exp(-Q/kT)cm2s-1 with D0=2.3x10-14cm2s-1 and Q=0.52eV

Proteinuria en gestantes atendidas en el Hospital Regional Eleazar Guzmán Barrón, Chimbote 2019

La presencia de proteínas con valores > de 150mg/dl en 24 horas durante el embarazo, parto y puerperio es un indicador de trastorno hemodinámico y metabólico, que puede determinar la vía del parto, el momento de nacimiento, tamizar los resultados con eficacia es responsabilidad del tecnólogo médico información que resulta importante para la toma de decisiones. Tiene como objetivos. Identificar los niveles de proteinuria a las gestantes según edad, paridad, tipo de embarazo, edad gestacional, y caracterizar los niveles basales y patológicos. El diseño de la investigación es Básica, Descriptiva, No experimental, Cuantitativa, Prospectiva, de corte Transversal, con una población de 186 gestantes, se elaboró una ficha de recolección de datos los mismos que fueron procesados con el software SPSS 25 y Excel 19., Los resultados fueron , De las 186 muestras tamizadas el 27% (50) presentaron valores de proteínas superiores a 150mg/dl en 24 horas, distribuidas en adolescentes, edad materna adecuada, edad materna avanzada, embarazos prematuros y A términos, el nivel máximo de proteinuria alcanzo los 673mg/dl en 24 horas, Concluyendo que las proteínas elevadas pueden presentarse durante el embarazo independientemente de la edad gestacional, edad del paciente, tamizarlas oportunamente permite mejoras tomas de decisiones en beneficio del binomio madre-niño.Tesi

Electrochemical removal of anodic aluminium oxide templates for the production of phase-pure cuprous oxide nanorods for antimicrobial surfaces.

Antimicrobial surfaces are ones that incapacitate or kill pathogens landing on them, which could allow for self-sanitising surfaces for hospitals or implants, ensuring healthier stays and procedures. Cuprous compounds such as Cu2O are especially effective at incapacitating both viruses and bacteria, and nanorod arrays have been shown to prevent the adhesion of pathogens and mechanically deform bacteria to the point that their cell walls rupture. A Cu2O nanorod array should therefore allow for the exploitation of both of these effects. In the present work, an electrochemical method is introduced, where Cu2O nanorods formed in a substrate-supported anodic aluminium oxide (AAO) template are held at a stable electrochemical potential throughout the removal of the AAO template. This avoids the partial reduction of the nanorods from Cu2O to Cu that was observed during chemical removal of the template, which was attributed to the presence of residual aluminium from the template fabrication process that reacts with the etchant and lowers the electrochemical potential of the nanorods to a value that favours reduction. Using the electrochemical removal method, the reliable production of phase-pure, free-standing, crystalline Cu2O nanorod arrays on ITO/glass substrates is demonstrated. This simple method is compatible with nanorod arrays of any size

MIMO Grid Impedance Identification of Three-Phase Power Systems: Parametric vs. Nonparametric Approaches

A fast and accurate grid impedance measurement of three-phase power systems is crucial for online assessment of power system stability and adaptive control of grid-connected converters. Existing grid impedance measurement approaches typically rely on pointwise sinusoidal injections or sequential wideband perturbations to identify a nonparametric grid impedance curve via fast Fourier computations in the frequency domain. This is not only time-consuming, but also inaccurate during time-varying grid conditions, while on top of that, the identified nonparametric model cannot be immediately used for stability analysis or control design. To tackle these problems, we propose to use parametric system identification techniques (e.g., prediction error or subspace methods) to obtain a parametric impedance model directly from time-domain current and voltage data. Our approach relies on injecting wideband excitation signals in the converter's controller and allows to accurately identify the grid impedance in closed loop within one injection and measurement cycle. Even though the underlying parametric system identification techniques are well-studied in general, their utilization in a grid impedance identification setup poses specific challenges, is vastly underexplored, and has not gained adequate attention in urgent and timely power systems applications. To this end, we demonstrate in numerical experiments how the proposed parametric approach can accomplish a significant improvement compared to prevalent nonparametric methods.Comment: 7 pages, 7 figure

Reduction and reconstruction of multisymplectic Lie systems

A Lie system is a non-autonomous system of first-order ordinary differential equations describing the integral curves of a non-autonomous vector field taking values in a finite-dimensional real Lie algebra of vector fields, a so-called Vessiot–Guldberg Lie algebra. In this work, multisymplectic forms are applied to the study of the reduction of Lie systems through their Lie symmetries. By using a momentum map, we perform a reduction and reconstruction procedure of multisymplectic Lie systems, which allows us to solve the original problem by analysing several simpler multisymplectic Lie systems. Conversely, we study how reduced multisymplectic Lie systems allow us to retrieve the form of the multisymplectic Lie system that gave rise to them. Our results are illustrated with examples from physics, mathematics, and control theory.The authors acknowledge fruitful discussions and comments from our colleague MiguelC Muñoz-Lecanda. J de Lucas acknowledges partial financial support from the Project MINIATURA 5 of the Polish National Science Centre (NCN) under Grant Number Nr 2021/05/X/ST1/01797. X Gr`acia, X Rivas, N Román-Roy, and S Vilariño acknowledge partial financial support from the Spanish Ministerio de Ciencia e Innovaci´on and Gobierno de Arag´on projectsPGC2018-098265-B-C31, PGC2018-098265-B-C33, RED2018-102541T, and E48_20R. We also thank the anonymous referees, whose interesting comments and suggestions have helped us improve our article.Peer ReviewedPostprint (published version

Effects of lattice geometry on thermopower properties of the repulsive Hubbard mode

We obtain the Seebeck coefficient or thermopower $S$, which determines the conversion efficiency from thermal to electrical energy, for the two-dimensional Hubbard model on different geometries (square, triangular, and honeycomb lattices) for different electronic densities and interaction strengths. Using Determinantal Quantum Monte Carlo (DQMC) we find the following key results: (a) the bi-partiteness of the lattice affects the doping dependence of $S$; (b) strong electronic correlations can greatly enhance $S$ and produce non-trivial sign changes as a function of doping especially in the vicinity of the Mott insulating phase; (c) $S(T)$ near half filling can show non-monotonic behavior as a function of temperature. We emphasize the role of strong interaction effects in engineering better devices for energy storage and applications, as captured by our calculations of the power factor $PF=S^2 \sigma$ where $\sigma$ is the dc conductivity.Comment: 10 pages, 8 figure

Unusual magnetic relaxation behavior in La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3

We have carried out a systematic magnetic relaxation study, measured after applying and switching off a 5 T magnetic field to polycrystalline samples of La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3. The long time logarithmic relaxation rate (LTLRR), decreased from 10 K to 150 K and increased from 150 K to 195 K in La0.5Ca0.5MnO3. This change in behavior was found to be related to the complete suppression of the antiferromagnetic phase above 150 K and in the presence of a 5 T magnetic field. At 195 K, the magnetization first decreased, and after a few minutes increased slowly as a function of time. Moreover, between 200 K and 245 K, the magnetization increased throughout the measured time span. The change in the slope of the curves, from negative to positive at about 200 K was found to be related to the suppression of antiferromagnetic fluctuations in small magnetic fields. A similar temperature dependence of the LTLRR was found for the Nd0.5Sr0.5MnO3 sample. However, the temperature where the LTLRR reached the minimum in Nd0.5Sr0.5MnO3 was lower than that of La0.5Ca0.5MnO3. This result agrees with the stronger ferromagnetic interactions that exist in Nd0.5Sr0.5MnO3 in comparison to La0.5Ca0.5MnO3. The above measurements suggested that the general temperature dependence of the LTLRR and the underlying physics were mainly independent of the particular charge ordering system considered. All relaxation curves could be fitted using a logarithmic law at long times. This slow relaxation was attributed to the coexistence of ferromagnetic and antiferromagnetic interactions between Mn ions, which produced a distribution of energy barriers.Comment: Accepted to PRB as a regular article, 10 figures, Scheduled Issue: 01 June 200

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to the substantiation of health claims related to various microorganisms and changes in bowel function, and digestion and absorption of nutrients (ID 960, 961, 967, 969, 971, 975, 983, 985, 994, 996, 998, 1006, 1014), decreasing potentially pathogenic gastro-intestinal microorganisms (ID 960, 967, 969, 971, 975, 983, 985, 994, 996, 998, 1006, 1014), and stimulation of immunological responses (ID 962, 968, 970, 972, 976, 984, 986, 995, 997, 999, 1007, 1015) (further assessment) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

<p>Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to provide a scientific opinion on health claims pursuant to Article 13 of Regulation (EC) No 1924/2006 in the framework of further assessment related to various microorganisms and changes in bowel function, and digestion and absorption of nutrients, decreasing potentially pathogenic gastro-intestinal microorganisms, and stimulation of immunological responses. The food constituents, <em>Bifidobacterium animalis </em>subsp.<em> lactis</em> THT 010801, <em>Bifidobacterium longum </em>subsp. <em>infantis</em> THT 010201, <em>Bifidobacterium longum </em>subsp.<em> longum</em> THT 010301, <em>Bifidobacterium pseudolongum </em>subsp.<em> pseudolongum</em> THT 010501, <em>Lactobacillus casei</em> THT 030401, <em>Lactobacillus gasseri</em> THT 031301, <em>Lactobacillus helveticus</em> THT 031102, <em>Lactobacillus plantarum</em> THT 030701, <em>Lactobacillus plantarum</em> THT 030707, <em>Lactobacillus reuteri</em> THT 030802, <em>Lactobacillus salivarius</em> THT 031001 and <em>Streptococcus thermophilus</em> THT 070102, are sufficiently characterised. The evidence provided did not establish that the proposed claimed effect, stimulation of immunological responses, is a beneficial physiological effect. The references provided for the health claims related to changes in bowel function and decreasing potentially pathogenic gastro-intestinal microorganisms included studies which assessed the effects of food constituents other than the food constituents which are the subject of the claims and/or investigated health outcomes unrelated to the claimed effects. No human studies which investigated the effects of the food constituents on appropriate measures of the claimed effects were provided. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of the food constituents and the claimed effects evaluated in this opinion.</p&gt

Fabrication and evaluation of a micro(bio)sensor array chip for multiple parallel measurements of important cell biomarkers

© 2014 by the authors; licensee MDPI, Basel, Switzerland. This report describes the design and development of an integrated electrochemical cell culture monitoring system, based on enzyme-biosensors and chemical sensors, for monitoring indicators of mammalian cell metabolic status. MEMS technology was used to fabricate a microwell-format silicon platform including a thermometer, onto which chemical sensors (pH, O2) and screen-printed biosensors (glucose, lactate), were grafted/deposited. Microwells were formed over the fabricated sensors to give 5-well sensor strips which were interfaced with a multipotentiostat via a bespoke connector box interface. The operation of each sensor/biosensor type was examined individually, and examples of operating devices in five microwells in parallel, in either potentiometric (pH sensing) or amperometric (glucose biosensing) mode are shown. The performance characteristics of the sensors/biosensors indicate that the system could readily be applied to cell culture/toxicity studies