The secondary electron (SE) yield, delta, was measured from 24 different elements at low primary beam energy (250-5,000 eV). Surface contamination affects the intensity of delta but not its variation with primary electron energy. The experiments suggest that the mean free path of SEs varies across the d bands of transition metals in agreement with theory. Monte Carlo simulations suggest that surface plasmons may need to be included for improved agreement with experiment.

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The electron backscattering factor was measured from 24 different elements at low primary beam energy (250-5,000 eV). The results were compared with Monte Carlo simulations from a variety of freely available programs and an in-house developed program. The results suggest that a thin film of oxide can modify the backscattering factor at low primary energy. In addition, a number of problems have been identified with the freely available programs.

Surface fogging is a common phenomenon that can have significant and detrimental effects on surface transparency and visibility. It affects the performance in a wide range of applications including windows, windshields, electronic displays, cameras, mirrors, and eyewear. A host of ongoing research is aimed at combating this problem by understanding and developing stable and effective anti-fogging coatings that are capable of handling a wide range of environmental challenges "passively" without consumption of electrical energy. Here we introduce an alternative approach employing sunlight to go beyond state-of-the-art techniques-such as superhydrophilic and superhydrophobic coatings-by rationally engineering solar absorbing metasurfaces that maintain transparency, while upon illumination, induce localized heating to significantly delay the onset of surface fogging or decrease defogging time.For the same environmental conditions, we demonstrate that our metasurfaces are able to reduce defogging time by up to four-fold and under supersaturated conditions inhibit the nucleation of condensate outperforming conventional state-of-the-art approaches in terms of visibility retention. Our research illustrates a durable and environmentally sustainable approach to passive anti-fogging and defogging for transparent surfaces. This work opens up the opportunity for large-scale manufacturing that can be applied to a range of materials, including polymers and other flexible substrates.

ABSTRACT:The electrostatic potentials and average local ionization energies computed on the molecular surfaces of four tetracyclines have been investigated with the objective of identifying common features as well as subtle differences that may be related to their biological activities. The four are the parent molecule tetracycline, chlortetracycline, oxytetracycline, and doxycyline. The calculations were carried out at the HF/STO-3G * //STO-3G * level. Our electrostatic potential results show that each molecule has a large negative region that extends along its lower portion, consistent with its ability to complex Ca 2+ and Mg 2+ ions. Although the surface electrostatic potentials of the four tetracyclines show many similarities, our statistical measure of local polarity allows us to label doxycycline as the one with the lowest degree of local polarity, consistent with its longer half-life in vivo. The regions in the tetracyclines with the most reactive electrons are the amide nitrogen lone pairs and certain carbons of the outermost rings.