619 research outputs found
A microfabricated sensor for thin dielectric layers
We describe a sensor for the measurement of thin dielectric layers capable of
operation in a variety of environments. The sensor is obtained by
microfabricating a capacitor with interleaved aluminum fingers, exposed to the
dielectric to be measured. In particular, the device can measure thin layers of
solid frozen from a liquid or gaseous medium. Sensitivity to single atomic
layers is achievable in many configurations and, by utilizing fast, high
sensitivity capacitance read out in a feedback system onto environmental
parameters, coatings of few layers can be dynamically maintained. We discuss
the design, read out and calibration of several versions of the device
optimized in different ways. We specifically dwell on the case in which
atomically thin solid xenon layers are grown and stabilized, in cryogenic
conditions, from a liquid xenon bath
Adsorption of Superplasticizers on Model Powders: Temperature dependance, effect on Zeta Potential and Role of Chemical Structure
Retarding cement hydration by increasing temperature
Trabajo presentado a la 12th International Conference on Superplasticizers and Other Chemical Admixtures in Concrete, celebrada en Bejing (China) del 28 al 31 de octubre de 2018.Specific polymer structures at particular dosages have been identified to be able to delay cement hydration as temperature increases. The aim of the present work is to understand the underlying mechanisms involved behind this unexpected phenomenon. In particular, hydration kinetics of chemically admixed cement pastes at different temperatures have been related to the mineralogical changes in pastes, chemical composition of the pore solution and rheological properties. Results have demonstrated a dramatic increase in the low- concentration elements (Si, Al, Mg and Fe) in the pore solution of admixed samples hydrated at room temperature. At this temperature, nano-particles (polymer aggregates involving complexes and/or organoaluminates) have been detected. In contrast, nano-particles are not present at higher temperatures, when the delay of hydration is observed. This could lead to a higher amount of free polymer in the pore solution leading to a greater delay of silicates hydration.This research has been funded by the SP-SC 01-14 and SCCER-SoE projects
Obesity: A Biobehavioral Point of View
Excerpt: If you ask an overweight person, “Why are you fat?’, you will, almost invariably, get the answer, “Because 1 eat too much.” You will get this answer in spite of the fact that of thirteen studies, six find no significant differences in the caloric intake of obese versus nonobese subjects, five report that the obese eat significantly less than the nonobese, and only two report that they eat significantly more
Expression of South East Asian Ovalocytic Band 3 Disrupts Erythroblast Cytokinesis and Reticulocyte Maturation
A linear RFQ ion trap for the Enriched Xenon Observatory
The design, construction, and performance of a linear radio-frequency ion
trap (RFQ) intended for use in the Enriched Xenon Observatory (EXO) are
described. EXO aims to detect the neutrinoless double-beta decay of Xe
to Ba. To suppress possible backgrounds EXO will complement the
measurement of decay energy and, to some extent, topology of candidate events
in a Xe filled detector with the identification of the daughter nucleus
(Ba). The ion trap described here is capable of accepting, cooling, and
confining individual Ba ions extracted from the site of the candidate
double-beta decay event. A single trapped ion can then be identified, with a
large signal-to-noise ratio, via laser spectroscopy.Comment: 18 pages, pdflatex, submitted to NIM
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