65 research outputs found
Analysis of Ionic Domains on a Proton Exchange Membrane Using a Numerical Approximation Model Based on Electrostatic Force Microscopy
Understanding the ionic channel network of proton exchange membranes that dictate fuel cell performance is crucial when developing proton exchange membrane fuel cells. However, it is difficult to characterize this network because of the complicated nanostructure and structure changes that depend on water uptake. Electrostatic force microscopy (EFM) can map surface charge distribution with nano-spatial resolution by measuring the electrostatic force between a vibrating conductive tip and a charged surface under an applied voltage. Herein, the ionic channel network of a proton exchange membrane is analyzed using EFM. A mathematical approximation model of the ionic channel network is derived from the principle of EFM. This model focusses on free charge movement on the membrane based on the force gradient variation between the tip and the membrane surface. To verify the numerical approximation model, the phase lag of dry and wet Nafion is measured with stepwise changes to the bias voltage. Based on the model, the variations in the ionic channel network of Nafion with different amounts of water uptake are analyzed numerically. The mean surface charge density of both membranes, which is related to the ionic channel network, is calculated using the model. The difference between the mean surface charge of the dry and wet membranes is consistent with the variation in their proton conductivity. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Author keywords1
Non-monotonic quantum to classical transition in multiparticle interference
We experimentally demonstrate the non-monotonic dependence of genuine
many-particle interference signals on the particles' mutual distinguishability.
Our theoretical analysis shows that such non-monotonicity is a generic feature
of the quantum to classical transition in multiparticle correlation functions
of more than two particles
Observation of Young's Double-Slit Interference with the Three-Photon N00N State
Spatial interference of quantum mechanical particles exhibits a fundamental
feature of quantum mechanics. A two-mode entangled state of N particles known
as N00N state can give rise to non-classical interference. We report the first
experimental observation of a three-photon N00N state exhibiting Young's
double-slit type spatial quantum interference. Compared to a single-photon
state, the three-photon entangled state generates interference fringes that are
three times denser. Moreover, its interference visibility of is
well above the limit of 0.1 for spatial super-resolution of classical origin.
The demonstration of spatial quantum interference by a N00N state composed of
more than two photons represents an important step towards applying quantum
entanglement to technologies such as lithography and imaging
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