RESUMEN
We studied the physical aging of glycerol in response to upward temperature steps of amplitude ranging from 0.3 to 18 K. This was done using a specially designed experimental setup allowing quick heating of a liquid film while measuring the evolution of its dielectric properties. Despite the nonlinear evolution of these observables for large steps, a fictive temperature could be obtained. In the case of moderate step amplitudes, we checked that the material time approach in its simplest form, the single parameter aging (SPA), applies well. The memory kernel extracted from the quasi-linear regime was used to test its frontiers of validity for significant step amplitudes. We showed that the observations deviate from the prediction of the material time framework and of SPA simultaneously. As these approaches link aging to equilibrium dynamics, our results help set the bounds beyond which new theoretical arguments are needed.
RESUMEN
We report an original method for directly fabricating gold nanoparticles (Au NPs) in a polymer matrix using a thermal treatment technique and theoretically and experimentally investigate their plasmonic properties. The polymeric-metallic nanocomposite samples were first prepared by simply mixing SU-8 resist and Au salt with different concentrations. The Au NPs growth was triggered inside the polymer through a thermal process on a hot plate and in air environment. The Au NPs creation was confirmed by the color of the nanocomposite thin films and by absorption spectra measurements. The Au NPs sizes and distributions were confirmed by transmission electron microscope measurements. It was found that the concentrations of Au salt and the annealing temperatures and durations are all crucial for tuning the Au NPs sizes and distributions, and, thus, their optical properties. We also propose a simulation model for calculations of Au NPs plasmonic properties inside a polymer medium. We realized that Au NPs having large sizes (50 to 100 nm) play an important role in absorption spectra measurements, as compared to the contribution of small NPs (<20 nm), even if the relative amount of big Au NPs is small. This simple, low-cost, and highly reproducible technique allows us to obtain plasmonic NPs within polymer thin films on a large scale, which can be potentially applied to many fields.
RESUMEN
This paper presents the dataset of a survey on Vietnamese female students' behavioral intention to use video conferencing tools (VCTs; e.g. Zoom, Microsoft Teams or Google Hangout) in COVID-19 pandemic. The questionnaire was designed based on the Technology Acceptance Model according to the result of research conducted by [1] and [2]. The survey was conducted on an online platform using the questionnaire of 21 items to collect the information of respondents' characteristics and their perception on computer self-efficacy, computer playfulness, COVID-19 context, behavioral intention to Use VCTs. The dataset contains 254 valid responses from female students who have been in distance learning in Vietnam. It can serve as a reference source for future studies on educational equity and for policy making on distance education.
RESUMEN
We investigated the in vivo activity of crude water extracts of Ajuga remota Benth (Labiatae) against Plasmodium berghei in mice using plants harvested from two areas in Kenya where the plant is commonly used to treat malaria. The extract was tested using a 4-day test at a dose of 30 mg/kg/day (equivalent to 0.2 ml solution per mouse). Wet leaf extract was the most effective with 90.4% suppression of parasitemia. Extract from air-dried and powdered flowers were the least effective with 17.2% suppression of parasitemia.
