University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

Sandwich-Like Heterostructures of MoS2/Graphene with Enlarged Interlayer Spacing and Enhanced Hydrophilicity as High-Performance Cathodes for Aqueous Zinc-Ion Batteries

Abstract: Layered materials have great potential as cathodes for aqueous zinc-ion batteries (AZIBs) because of their facile 2D Zn2+ transport channels; however, either low capacity or poor cycling stability limits their practical applications. Herein, two classical layered materials are innovatively combined by intercalating graphene into MoS2 gallery, which results in significantly enlarged MoS2 interlayers (from 0.62 to 1.16 nm) and enhanced hydrophilicity. The sandwich-structured MoS2 /graphene nanosheets self-assemble into a flower-like architecture that facilitates Zn-ion diffusion, promotes electrolyte infiltration, and ensures high structural stability. Therefore, this novel MoS2 /graphene nanocomposite exhibits exceptional high-rate capability (285.4 mA h g-1 at 0.05 A g-1 with 141.6 mA h g-1 at 5 A g-1 ) and long-term cycling stability (88.2% capacity retention after 1800 cycles). The superior Zn2+ migration kinetics and desirable pseudocapacitive behaviors are confirmed by electrochemical measurements and density functional theory computations. The energy storage mechanism regarding the highly reversible phase transition between 2H- and 1T-MoS2 upon Zn-ion insertion/extraction is elucidated through ex situ investigations. As a proof of concept, a flexible quasi-solid-state zinc-ion battery employing the MoS2 /graphene cathode demonstrates great stability under different bending conditions. This study paves a new direction for the design and on-going development of 2D materials as high-performance cathodes for AZIBs.

Sheet-like MoSe2/C composites with enhanced Li-ion storage properties

Abstract: Carbon–transition-metal dichalcogenide composites have demonstrated favourable properties for lithium-ion batteries. Herein, a sheet-like MoSe2/C composite was successfully synthesized using Na2MoO4·2H2O, Se powder and glucose as the source materials through a simple hydrothermal method and subsequent annealing treatment. The as-synthesized sheet-like MoSe2/C composite was characterized by XRD, FSEM, FTEM, and XPS. When fabricated into a lithium-ion battery, the composite exhibited improved Li storage properties compared to a pure MoSe2 electrode, including a good cycling stability and high rate capacity. After 50 cycles, a reversible specific capacity of about 576.7 mA h g−1 at a current density of 100 mA g−1 was still achieved for the sheet-like composite electrode.

Thermoelectric Nanogenerators Based on Single Sb-Doped ZnO Micro/Nanobelts

Abstract: We demonstrate a thermoelectric nanogenerator (NG) made from a single Sb-doped ZnO micro/nanobelt that generates an output power of about 1.94 nW under a temperature difference of 30 K between the two electrodes. A single Sb-doped ZnO microbelt was bonded at its ends on a glass substrate as a NG, which can give an output voltage of 10 mV and an output current of 194 nA. The single Sb-doped ZnO microbelt shows a Seebeck coefficient of about −350 μV/K and a high power factor of about 3.2 × 10–4 W/mK2. The fabricated NG demonstrated its potential to work as a self-powered temperature sensor with a reset time of about 9 s.

Self-organization paradigms and optimization approaches for cognitive radio technologies: a survey

Abstract: Cognitive radio is regarded as a promising technology to provide high bandwidth to mobile users via heterogeneous wireless network architectures and dynamic spectrum access techniques. However, cognitive radio networks may also impose some challenges due to various factors such as the ever increasing complexity of network architecture, the high cost of configuring and managing large-scale networks, the fluctuating nature of the available spectrum, diverse QoS requirements of various applications, and the intensifying difficulties of centralized control. A plethora of work has been carried out to address the challenges aforementioned by employing cognitive radio functionalities with self-organization features. In this article, variant aspects of selforganization paradigms in cognitive radio networks, including critical functionalities of MACand network-layer operations, are surveyed. The main contributions of this survey include introducing the fundamentals of existing cognitive radio and self-organization techniques as well as their current progress, surveying critical cognitive radio issues (including common control channel management, cooperative spectrum sensing, bioinspired spectrum sharing, network scalability and adaptive routing) as well as their self-organization features, and identifying new directions and open problems in cognitive radio networks.