Scaling of cluster heterogeneity in percolation transitions

We investigate a critical scaling law for the cluster heterogeneity $H$ in site and bond percolations in $d$-dimensional lattices with $d=2,...,6$. The cluster heterogeneity is defined as the number of distinct cluster sizes. As an occupation probability $p$ increases, the cluster size distribution evolves from a monodisperse distribution to a polydisperse one in the subcritical phase, and back to a monodisperse one in the supercritical phase. We show analytically that $H$ diverges algebraically approaching the percolation critical point $p_c$ as $H\sim |p-p_c|^{-1/\sigma}$ with the critical exponent $\sigma$ associated with the characteristic cluster size. Interestingly, its finite-size-scaling behavior is governed by a new exponent $\nu_H = (1+d_f/d)\nu$ where $d_f$ is the fractal dimension of the critical percolating cluster and $\nu$ is the correlation length exponent. The corresponding scaling variable defines a singular path to the critical point. All results are confirmed by numerical simulations.Comment: 4 pages, 4 figure

Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer

In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the pn junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it. © 2012 Baek et al.1

Predicting Density of States via Multi-modal Transformer

The density of states (DOS) is a spectral property of materials, which provides fundamental insights on various characteristics of materials. In this paper, we propose a model to predict the DOS by reflecting the nature of DOS: DOS determines the general distribution of states as a function of energy. Specifically, we integrate the heterogeneous information obtained from the crystal structure and the energies via multi-modal transformer, thereby modeling the complex relationships between the atoms in the crystal structure, and various energy levels. Extensive experiments on two types of DOS, i.e., Phonon DOS and Electron DOS, with various real-world scenarios demonstrate the superiority of DOSTransformer. The source code for DOSTransformer is available at https://github.com/HeewoongNoh/DOSTransformer.Comment: ICLR 2023 Workshop on Machine Learning for Materials (ML4Materials

Dual Therapy with Cidofovir and Mirtazapine for Progressive Multifocal Leukoencephalopathy in a Sarcoidosis Patient

Background: Progressive multifocal leukoencephalopathy (PML) is a demyelinating central nervous system disease caused by JC virus (JCV) reactivation in immunocompromised patients. The disease course of PML is often progressive, fatal and at present, there are few reports on successful treatment outcomes. Case Report: A 45-year-old man with systemic sarcoidosis presented with rapidly progressive dementia and right hemiparesis. The patient was diagnosed with PML as confirmed via brain biopsy and JCV PCR. With a combination treatment of cidofovir and mirtazapine, there was significant improvement of neurological symptoms without measurable functional deficit. Conclusion: This case suggests that dual therapy with cidofovir and mirtazapine might be an effective treatment option in PML patients with sarcoidosis

Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

Over the last several decades, phenomena related to critical heat flux (CHF) on structured surfaces have received a large amount of attention from the research community. The purpose of such research has been to enhance the safety and efficiency of a variety of thermal systems. A number of theories have been put forward to explain the key CHF enhancement mechanisms on structured surfaces. However, these theories have not been confirmed experimentally because of limitations in the available visualization techniques and the complexity of the phenomena. To overcome these limitations and elucidate the CHF enhancement mechanism on the structured surfaces, we introduce synchrotron x-ray imaging with high spatial (similar to 2 mu m) and temporal (similar to 20,000 Hz) resolutions. This technique has enabled us to confirm that capillary-induced flow is the key CHF enhancement mechanism on structured surfaces.11Ysciescopu

Through the Spherical Looking-Glass: Asymmetry Enables Multicolored Internal Reflection in Cholesteric Liquid Crystal Shells

Spheres of cholesteric liquid crystal generate dynamic patterns due to selec- tive reflection from a helical structure subject to continuously curved bounda- ries. So far the patterns are investigated exclusively as function of reflections at the sphere exterior. Here it is shown that the cholesteric shells in a microfluidics produced double emulsion enable also a sequence of internal reflections if the shells have sufficiently thin top and thick bottom. While such asymmetry is promoted by buoyancy when the internal droplet has lower density than the liquid crystal, the elasticity of the cholesteric helix prefers a symmetric shell geometry, acting against gravity. This subtle balance can hide the internal reflections for long time. Eventually, however, the asymmetry is established, revealing a new class of photonic patterns characterized by colored sharp concentric rings. With the complete knowledge of the diverse light-reflecting behavior of cholesteric liquid crystal shells, and utilizing the tunability of the structure period by, e.g., temperature, electric field, or expo- sure to various chemical species as well as polymer stabilization for making the shells long-term stable, they may be developed into remarkable new optical elements for photonics, sensing, or security pattern generation