Nanjing University

About: Nanjing University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 85961 authors who have published 105504 publications receiving 2289036 citations. The organization is also known as: NJU & Nanking University.

Critical Challenges in Rechargeable Aprotic Li–O2 Batteries

Abstract: Rechargeable aprotic Li–O2 batteries are one of the most promising next-generation battery technologies that can deliver extremely high energy density. In the past decades, this technology has attracted worldwide attention, and considerable progress has been achieved. However, numerous critical scientific challenges remain to be solved for practical applications. A specific discussion of recent progress from the perspective of the stable aprotic Li–O2 system with high energy efficiency is presented. The discussion is highlighted on the reaction mechanisms on air cathode, stability of cell components in semi-open surroundings, and improvement of battery performance by catalyst design. Challenges and perspectives are also presented. This study provides an intensive understanding of aprotic Li–O2 batteries and offers an important guideline for developing reversible and high-efficiency Li–O2 batteries.

Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector

Abstract: Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy of 13 TeV collected in 2015 and 2016 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons (e or μ). Several signal regions are considered with increasing requirements on the missing transverse momentum above 250 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.

Secrecy Rate Maximization for Intelligent Reflecting Surface Assisted Multi-Antenna Communications

Abstract: We investigate transmission optimization for intelligent reflecting surface (IRS) assisted multi-antenna systems from the physical-layer security perspective. The design goal is to maximize the system secrecy rate subject to the source transmit power constraint and the unit modulus constraints imposed on phase shifts at the IRS. To solve this complicated non-convex problem, we develop an efficient alternating algorithm where the solutions to the transmit covariance of the source and the phase shift matrix of the IRS are achieved in closed form and semi-closed form, respectively. The convergence of the proposed algorithm is guaranteed theoretically. Simulation results validate the performance advantage of the proposed optimized design.