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Brandaleze Elena Ávalos M. Benavidez Edgardo 《Journal of Thermal Analysis and Calorimetry》2022,147(1):219-228
Journal of Thermal Analysis and Calorimetry - Recent advances in the technology of black refractories for steel continuous casting promote the development of materials that operate at extreme... 相似文献
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Dr. Esther Frederick Dr. Quinn Campbell Dr. Igor V. Kolesnichenko Dr. Luis F. Peña Dr. Angelica Benavidez Dr. Evan M. Anderson Dr. David R. Wheeler Dr. Shashank Misra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13337-13341
Ultradoping introduces unprecedented dopant levels into Si, which transforms its electronic behavior and enables its use as a next-generation electronic material. Commercialization of ultradoping is currently limited by gas-phase ultra-high vacuum requirements. Solvothermal chemistry is amenable to scale-up. However, an integral part of ultradoping is a direct chemical bond between dopants and Si, and solvothermal dopant-Si surface reactions are not well-developed. This work provides the first quantified demonstration of achieving ultradoping concentrations of boron (∼1e14 cm2) by using a solvothermal process. Surface characterizations indicate the catalyst cross-reacted, which led to multiple surface products and caused ambiguity in experimental confirmation of direct surface attachment. Density functional theory computations elucidate that the reaction results in direct B−Si surface bonds. This proof-of-principle work lays groundwork for emerging solvothermal ultradoping processes. 相似文献
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Edgardo R. Benavidez Carlos J. R. González Oliver 《Journal of Thermal Analysis and Calorimetry》2010,99(2):369-375
Organometallic-derived ceramic compositions surrounding YBa2Cu3O7–x (123) were evaluated via DTA-TG runs and dilatometric densification. The compositions were either Y, Ba or Cu deficient respect
to 123. For the Yttrium deficient compact the presence of liquids containing 0–1.3 mole %YO1.5—capable of dissolving the 123 grains—can promote a rapid sintering behavior. For Copper deficient compact the main densification/contraction
mechanisms were delayed till 985 °C. For both Barium and Copper deficient compacts a strong exudation of liquids was detected
at 990 °C and 1020 °C, respectively. 相似文献
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In this work, an isocratic high-performance liquid chromatographic method for quantitation of liposomal benznidazole (BNZ) in biological tissues is presented. The method comprises protein precipitation together with an efficient extraction of bulk or liposomal BNZ with acetonitrile-dimethylsulfoxide (1:1, v/v) at a 2:1 (extraction solvent-tissue matrix, v/v or /vw) ratio; the process is completed by a final precipitation with trichloroacetic acid. The resultant supernatants are assayed chromatographically using a Kromasil C18 (25- x 0.4-cm i.d., 100 A, 5- microm particle size), with an isocratic mobil phase consisting of acetonitrile-water (40:60, v/v), a flow rate of 0.9 mL/min, and detected at 324 nm. Bulk BNZ is used as a reference standard for the analysis of samples containing liposomal BNZ. The assay is linear over a concentration range of 0.75 (the lowest quantity of analyte determined with precision and accuracy of >or= 20%) to 25 microg/mL-g in all liquid and solid matrices. Within-day precision is better than 6.4% in plasma and 8.6% in liver, the same for the two assayed concentrations. Between-day precision is 5.4% and 12.3% in plasma and 9% and 6.9% in liver for the two assayed concentrations, respectively. The absolute recoveries range between 70% and 97%. Therefore, the method is accurate and precise to be employed for detection of minor quantities of liposomal BNZ in biological tissues. 相似文献
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Brandaleze Elena Valentini Marcelo Santini Leandro Benavidez Edgardo 《Journal of Thermal Analysis and Calorimetry》2018,133(1):271-277
Journal of Thermal Analysis and Calorimetry - Casting powders are commonly used in continuous casting of steels. The chemical composition of these powders is based on various oxides, carbonaceous... 相似文献
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E. Benavidez L. Santini E. Brandaleze 《Journal of Thermal Analysis and Calorimetry》2011,103(2):485-493
Mold fluxes develop important functions during steel continuous casting process. To obtain a free-defect product the melting
rate of mold flux is an important property to be controlled. The melting rate depends on the reactivity of carbonaceous material
added to these powders as carbon source. In this article, the decomposition kinetic of two carbonaceous materials added to
mold flux: petroleum coke and synthetic graphite, was analyzed. By measuring mass loss at different heating rates the decomposition
reaction was determined on both types of materials. Applying several kinetic models of non-isothermal decomposition, the average
activation energy E = 48 kJ/mol to mold powder with 15 wt% coke and E = 67 kJ/mol to one with 15 wt% graphite was determined. A first order of reaction (n = 1) associated to the decomposition process was assumed to both types of materials. The lower activation energy presented
by mold powder-15 wt% petroleum coke indicated a higher reactivity of this material. A higher level of variation of E and n values with decomposition degree and temperature observed in the powder with petroleum coke was associated to a less thermally
stable material along with a more complex degradation process. 相似文献
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Dr. Tomás E. Benavidez Prof. José D. S. Guerra Prof. Carlos D. Garcia 《Chemphyschem》2022,23(10):e202100914
This report describes the application of dielectric spectroscopy as a simple and fast way to guide protein adsorption experiments. Specifically, the polarization behavior of a layer of adsorbed lysozyme was investigated using a triangular-wave signal with frequencies varying from 0.5 to 2 Hz. The basic experiment, which can be performed in less than 5 min and with a single sample, not only allowed confirming the susceptibility of the selected protein towards the electric signal but also identified that this protein would respond more efficiently to signals with lower frequencies. To verify the validity of these observations, the adsorption behavior of lysozyme onto optically transparent carbon electrodes was also investigated under the influence of an applied alternating potential. In these experiments, the applied signal was defined by a sinusoidal wave with an amplitude of 100 mV and superimposed to +800 mV (applied as a working potential) and varying the frequency in the 0.1–10000 Hz range. The experimental data showed that the greatest adsorbed amounts of lysozyme were obtained at the lowest tested frequencies (0.1–1.0 Hz), results that are in line with the corresponding dielectric features of the protein. 相似文献
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Tomás E. Benavidez Raúl H. Capra Cecilia I. Alvarez Ana M. Baruzzi 《Electroanalysis》2009,21(7):837-843
An amperometric electrode for oxalate determination immobilizing the oxalate oxidase in a mucin/chitosan (muc/chit) gel with glutaraldehyde as crosslinking agent is presented. The effect of muc/chit weight ratio and volume percent (vol.%) of glutaraldehyde was studied. A very low dynamic response was observed in the case of 100% chitosan with 5 vol.% crosslinking agent. The addition of mucin to chitosan for enzyme immobilization resulted in a biosensor with much better performance, concerning to dynamic response, sensitivity, and stability, with 75% of the initial response after two months. The ratio muc/chit 70/30 was considered optimum for the immobilization. A slight crosslinking and the incorporation of mucin largely influences the swelling and diffusion of the analyte; a direct effect of these properties on the calibration slope was found; the hydrophilic environment for the biomolecule also favor the enzymatic activity through a higher enzyme‐substrate interaction. 相似文献
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