1,643 research outputs found
Gradient estimates for degenerate quasi-linear parabolic equations
For a general class of divergence type quasi-linear degenerate parabolic
equations with differentiable structure and lower order coefficients form
bounded with respect to the Laplacian we obtain -estimates for the
gradients of solutions, and for the lower order coefficients from a Kato-type
class we show that the solutions are Lipschitz continuous with respect to the
space variable
A method validation for simultaneous determination of phthalates and bisphenol A released from plastic water containers
Phthalates (or phthalate esters, PAEs) and bisphenol A (BPA) are widely used in various industries, particularly in the fields of cosmetics and packaging, and they increase the malleability and workability of materials. As a result of their use, some international health organizations have begun to study them. In this study, the authors developed a methodology for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP); dibutyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP); di-n-octyl-phthalate (DnOP) and bisphenol A (BPA) from drinking and non-potable waters. The extraction of PAEs and BPA was performed using a solvent-based dispersive liquid-liquid microextraction (SB-DLLME) method. The analytical determination was performed using a gas chromatography-ion trap mass spectrometry (GC-IT/MS) analysis. The entire procedure was validated as recoveries were studied according to the volume and the extraction solvent used, pH, and ionic strength. Dynamic linearity ranges and linear equations of all the compounds were experimentally determined as well as the limit of detection (LOD) (1-8 ng mL-1) and the limit of quantification (LOQ) (5-14 ng mL-1), reproducibility, and sensitivity. The method was applied to 15 water samples (mineral water and tap water) for determining PAEs and BPA released from the plastic container. After the release simulation, four PAEs (i.e., DiBP, DBP, DHEP, and DnOP) were determined at very low concentrations (below 1.2 ng mL-1) in two water samples from (sport) bottles
Generation and detection of large and robust entanglement between two different mechanical resonators in cavity optomechanics
We investigate a general scheme for generating, either dynamically or in the
steady state, continuous variable entanglement between two mechanical
resonators with different frequencies. We employ an optomechanical system in
which a single optical cavity mode driven by a suitably chosen two-tone field
is coupled to the two resonators. Significantly large mechanical entanglement
can be achieved, which is extremely robust with respect to temperature.Comment: To appear in New J. Phys. Small extensions in response to the points
raised by the referee and Refs adde
Why do These Match? Explaining the Behavior of Image Similarity Models
Explaining a deep learning model can help users understand its behavior and
allow researchers to discern its shortcomings. Recent work has primarily
focused on explaining models for tasks like image classification or visual
question answering. In this paper, we introduce Salient Attributes for Network
Explanation (SANE) to explain image similarity models, where a model's output
is a score measuring the similarity of two inputs rather than a classification
score. In this task, an explanation depends on both of the input images, so
standard methods do not apply. Our SANE explanations pairs a saliency map
identifying important image regions with an attribute that best explains the
match. We find that our explanations provide additional information not
typically captured by saliency maps alone, and can also improve performance on
the classic task of attribute recognition. Our approach's ability to generalize
is demonstrated on two datasets from diverse domains, Polyvore Outfits and
Animals with Attributes 2. Code available at:
https://github.com/VisionLearningGroup/SANEComment: Accepted at ECCV 202
Sensitivity-bandwidth limit in a multi-mode opto-electro-mechanical transducer
An opto--electro--mechanical system formed by a nanomembrane capacitively
coupled to an LC resonator and to an optical interferometer has been recently
employed for the high--sensitive optical readout of radio frequency (RF)
signals [T. Bagci, \emph{et~al.}, Nature {\bf 507}, 81 (2013)]. Here we propose
and experimentally demonstrate how the bandwidth of such kind of transducer can
be increased by controlling the interference between two--electromechanical
interaction pathways of a two--mode mechanical system. With a
proof--of--principle device \new{operating at room temperature, we achieve a
sensitivity of 300 nV/Hz^(1/2) over a bandwidth of 15 kHz in the presence of
radiofrequency noise, and an optimal shot-noise limited sensitivity of 10
nV/Hz^(1/2) over a bandwidth of 5 kHz. We discuss strategies for improving the
performance of the device, showing that, for the same given sensitivity, a
mechanical multi--mode transducer can achieve a bandwidth} significantly larger
than that of a single-mode one
High-Pressure Synthesis of a Pentazolate Salt
The pentazolates, the last all-nitrogen members of the azole series, have
been notoriously elusive for the last hundred years despite enormous efforts to
make these compounds in either gas or condensed phases. Here we report a
successful synthesis of a solid state compound consisting of isolated
pentazolate anions N5-, which is achieved by compressing and laser heating
cesium azide (CsN3) mixed with N2 cryogenic liquid in a diamond anvil cell. The
experiment was guided by theory, which predicted the transformation of the
mixture at high pressures to a new compound, cesium pentazolate salt (CsN5).
Electron transfer from Cs atoms to N5 rings enables both aromaticity in the
pentazolates as well as ionic bonding in the CsN5 crystal. This work provides a
critical insight into the role of extreme conditions in exploring unusual
bonding routes that ultimately lead to the formation of novel high nitrogen
content species
D'Emma Bovary aĢ Gemma Bovery: une approche traductologique
Gemma Bovery de Posy Simmonds est lāune des reĢcritures les plus eĢtudieĢes de Madame Bovary. Parmi les diffeĢrentes manieĢres de consideĢrer cette reĢcriture en bande dessineĢe du roman de Flaubert, jāadopterai ici une perspective qui releĢve de la traductologie. La lecture que je propose dans cet article prend dāabord appui sur le concept bien connu de Ā« traduction interseĢmiotique Ā» de Roman Jakobson et cherche aĢ lire Gemma Bovery avec les outils propres aĢ cette branche de la traductologie connue sous le nom de critique des traductions. AĢ lāinteĢrieur de ce champ, le paradigme interpreĢtatif privileĢgieĢ sera celui proposeĢ par Lance Hewson, baseĢ sur deux niveaux : celui des Ā« effets de voix Ā» (choix traductifs qui modifient la voix du narrateur ou des personnages), et celui des Ā« effets dāinterpreĢtation Ā» (choix traductifs qui privileĢgient des pistes interpreĢtatives diffeĢrentes). Lāhorizon de ma recherche concernera dāabord les niveaux micro et meĢso-textuel (aĢ savoir, les choix ponctuels), afin de mieux appreĢcier le niveau macro-structurel (les choix strateĢgiques). Sur le plan theĢorique, il sera question de voir ce que les outils de la traductologie peuvent apporter aĢ lāanalyse dāune reĢcriture
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