On the hopping pattern design for D2D discovery with invariant

In this paper, we focus on the hopping pattern design for device-to-device (D2D) discovery. The requirements of hopping pattern is discussed, where the impact of specific system constraints, e.g., frequency hopping, is also taken into consideration. Specifically speaking, we discover and utilize the novel feature of resource hopping, i.e., "hopping invariant" to design four new hopping patterns and analyze their performance. The hopping invariant can be used to deliver information for specific users without extra radio resources, and due to the connection between hopping invariant and resource location, receiver complexity can be significantly reduced. Furthermore, our schemes are designed to be independent of discovery frame number, which makes them more suitable to be implemented in practical systems

Recent Advances in Noble Metal (Pt, Ru, and Ir)-Based Electrocatalysts for Efficient Hydrogen Evolution Reaction

Noble metal (Pt, Ru, and Ir)-based electrocatalysts are currently considered the most active materials for the hydrogen evolution reaction (HER). Although they have been associated with high cost, easy agglomeration, and poor stability during the HER reaction, recent efforts to intentionally tailor noble-metal-based catalysts have led to promising improvements, with lower cost and superior activity, which are critical to achieving large-scale production of pure hydrogen. In this mini-review, we focus on the recent advances in noble-metal-based HER electrocatalysts. In particular, the synthesis strategies to enhance cost-effectiveness and the catalytic activity for HER are highlighted

A New Code for Nonlinear Force-Free Field Extrapolation of the Global Corona

Reliable measurements of the solar magnetic field are still restricted to the photosphere, and our present knowledge of the three-dimensional coronal magnetic field is largely based on extrapolation from photospheric magnetogram using physical models, e.g., the nonlinear force-free field (NLFFF) model as usually adopted. Most of the currently available NLFFF codes have been developed with computational volume like Cartesian box or spherical wedge while a global full-sphere extrapolation is still under developing. A high-performance global extrapolation code is in particular urgently needed considering that Solar Dynamics Observatory (SDO) can provide full-disk magnetogram with resolution up to $4096\times 4096$. In this work, we present a new parallelized code for global NLFFF extrapolation with the photosphere magnetogram as input. The method is based on magnetohydrodynamics relaxation approach, the CESE-MHD numerical scheme and a Yin-Yang spherical grid that is used to overcome the polar problems of the standard spherical grid. The code is validated by two full-sphere force-free solutions from Low & Lou's semi-analytic force-free field model. The code shows high accuracy and fast convergence, and can be ready for future practical application if combined with an adaptive mesh refinement technique.Comment: Accepted by ApJ, 26 pages, 10 figure