Ultra-Thin Ion Exchange Membranes by Low Ionomer Blending for Energy Harvesting.

Exploring the utilization of ion exchange membranes (IEMs) in salinity gradient energy harvesting, a technique that capitalizes on the salinity difference between seawater and freshwater to generate electricity, this study focuses on optimizing PVDF to Nafion ratios to create ultra-thin membranes. Specifically, our investigation aligns with applications such as reverse electrodialysis (RED), where IEMs facilitate selective ion transport across salinity gradients. We demonstrate that membranes with reduced Nafion content, particularly the 50:50 PVDF:Nafion blend, retain high permselectivity comparable to those with higher Nafion content. This challenges traditional understandings of membrane design, highlighting a balance between thinness and durability for energy efficiency. Voltage-current analyses reveal that, despite lower conductivity, the 50:50 blend shows superior short-circuit current density under salinity gradient conditions. This is attributed to effective ion diffusion facilitated by the blend's unique microstructure. These findings suggest that blended membranes are not only cost-effective but also exhibit enhanced performance for energy harvesting, making them promising candidates for sustainable energy solutions. Furthermore, these findings will pave the way for advances in membrane technology, offering new insights into the design and application of ion exchange membranes in renewable energy.

Antireflective Transparent Conductive Oxide Film Based on a Tapered Porous Nanostructure.

A new architecture for antireflection (AR) has been developed to break the trade-off between the optical transmittance and the electrical conduction impeding the performance of transparent conductive oxide (TCO) films. The tapered porous nanostructure with a complex continuous refractive index effectively eliminates reflections from the interfaces between air and the TCO and TCO and the substrate. Compared to the conventional TCO film, the AR TCO film exhibited the same electrical conduction, with an average transmittance of 88.7% in the 400-800 nm range, a 10.3% increase. The new AR TCO film is expected to improve the performance of various optoelectronic devices.

Multi-Asymmetric Ion-Diode Membranes with Superior Selectivity and Zero Concentration Polarization Effect.

Biological ion channels exhibiting selective and rectified ion transport properties feature nanoscale asymmetries in their physical structure, chemical composition, and charge distribution. Inspired by this, a multi-asymmetric ion-diode membrane (IDM) having a heterojunction between a positively charged anodic aluminum oxide membrane with conical macropores and a negatively charged Nafion membrane with very narrow mesopores was designed and practically fabricated in this study. Experiments and theoretical calculations demonstrated that the proposed membrane has the highest selectivity among IDMs and provides complete suppression of the concentration polarization (CP) effect limiting the current density in ion-exchange membrane electrodialysis. These findings present direct evidence that the physical and chemical design of the channel structure can provide both superior selectivity and a zero CP effect to IDMs and practical fabrication methods of IDMs for diverse, promising membrane applications.

Late-Time Magnetogenesis Driven by Axionlike Particle Dark Matter and a Dark Photon.

We propose a mechanism generating primordial magnetic fields after the e^{+}e^{-} annihilations. Our mechanism involves an ultralight axionlike particle (ALP) which constitutes the dark matter and a dark U(1)_{X} gauge boson introduced to bypass the obstacle placed by the conductivity of cosmic plasma. In our scheme, a coherently oscillating ALP amplifies the dark photon field, and part of the amplified dark photon field is concurrently converted to the ordinary magnetic field through the ALP-induced magnetic mixing. For the relevant ALP mass range 10^{-21} eV≲m_{ϕ}≲10^{-17} eV, our mechanism can generate B∼10^{-24} G(m_{ϕ}/10^{-17} eV)^{5/4} with a coherent length λ∼(m_{ϕ}/10^{-17} eV)^{-1/2} kpc, which is large enough to provide a seed of the galactic magnetic fields. The mechanism also predicts a dark U(1)_{X} electromagnetic field E_{X}∼B_{X}∼80 nG(m_{ϕ}/10^{-17} eV)^{-1/4}, which can result in interesting astrophysical or cosmological phenomena by inducing the mixings between the ALP, ordinary photon, and dark photon states.

Curvature-Driven Rigid Nanowire Orientation inside Nanotube Walls.

Self-aligning of a rigid hard domain nanowire inside the nanotube wall has been found for a segmented block copolymer, and applicability of the attenuated total reflection (ATR) technique of Fourier transform infrared (FTIR) spectroscopy to obtain quantitative three-dimensional orientation information of the nanowires in the nanotube has been demonstrated. The preferential orientation of a nanowire along a nanocylinder is explained in terms of the curvature of the nanotube and the persistence length of the hard domain nanowire. This observation may pave the way to new fabrication methods for the anisotropic performance of one-dimensional structures, such as electrical conductivity, piezoelectricity, and photonic properties of polymeric nanofibers and nanotubes.

Transverse mass for pairs of gluinos.

We introduce a new observable, "gluino m_{T2}," which is an application of the Cambridge m_{T2} variable to the process where gluinos are pair produced in a proton-proton collision and each gluino subsequently decays into two quarks and one lightest supersymmetric particle, i.e., g[over ]g[over ]-->qqchi[over ]_{1};{0}qqchi[over ]_{1};{0}. We show that the gluino m_{T2} can be utilized to measure the gluino mass and the lightest neutralino mass separately and also the 1st and 2nd generation squark masses if squarks are lighter than the gluino, thereby providing a good first look at the pattern of sparticle masses experimentally.

QCD axion from a higher dimensional gauge field theory.

We point out that a QCD axion solving the strong CP problem can arise naturally from a parity-odd gauge field in five-dimensional (5D) orbifold field theory. The required axion coupling to the QCD anomaly comes from the 5D Chern-Simons coupling, and all other unwanted U(1)PQ breaking axion couplings can be avoided naturally by the 5D gauge symmetry and locality. If the fifth dimension is warped, the resulting axion scale is suppressed by a small warp factor compared to the Planck scale, thereby the model can generate naturally an intermediate axion scale fa = 10(10)-10(12) GeV.

Sneutrino-antisneutrino mixing and neutrino mass in anomaly-mediated supersymmetry breaking scenario.

In supersymmetric models with nonzero Majorana neutrino mass, the sneutrino and antisneutrino mix, which may lead to same-sign dilepton signals in future collider experiments. We point out that the anomaly-mediated supersymmetry breaking scenario has a good potential to provide an observable rate of such signals for the neutrino masses suggested by the atmospheric and solar neutrino oscillations. It is noted also that the sneutrino-antisneutrino mixing can provide much stronger information on some combinations of the neutrino masses and mixing angles than the neutrino experiments.