Showing papers by "University of South Carolina published in 2022"

Mo⁶⁺–P⁵⁺ co-doped Li₂ZnTi₃O₈ anode for Li-storage in a wide temperature range and applications in LiNi_0.5Mn_1.5O₄/Li₂ZnTi₃O₈ full cells

Abstract: LZM7TP3O co-doped with Mo 6+ and P 5+ , with excellent electrochemical performance at 0–55 °C, has been synthesized using a simple solid-state method. The LiNi 0.5 Mn 1.5 O 4 /LZM7TP3O full cell can power LED bulbs that emit different colors of light.

Mo6+-P5+ co-doped Li2ZnTi3O8 anode for Li-storage in wide temperature range and applications in LiNi0.5Mn1.5O4/Li2ZnTi3O8 full cells

Abstract: One-step solid-state method has been used to synthesize Li2ZnTi3O8 (LZTO) co-doped by Mo6+ and P5+ ions (LZM7TP3O). The structure stability, pore size and specific surface area have been improved via the strategy. In addition, LZM7TP3O has high ionic and electronic conductivities, and small transfer resistance. So, co-doping strategy tremendously enhances the electrochemical performance of LZM7TP3O in the wide temperature range. Cycling for 600 cycles at 25 °C, no capacity fading occurs for LZM7TP3O based on the 2nd cycle at 1 A g-1. 180.5 mAh g-1 is still kept at 3 A g-1 for the 120th cycle. Cycling for 100 cycles at 55 °C, no capacity decay occurs for LZM7TP3O relative to the 2nd cycle at 1 A g-1. At 0 °C, cycling for 1000 cycles at 0.5 A g-1, no capacity loses relative to the 2nd cycle. At 0.5 C, the initial discharge specific capacity of the LiNi0.5Mn1.5O4/LZM7TP3O full cell can reach 214.3 mAh g-1 in 2-4.55 V, when LZM7TP3O is used as the anode of the full cell. Moreover, the full cell can power red, green and blue light emitting diode (LED) bubbles. The results indicate that LZM7TP3O is an appealing anode of lithium-ion batteries.

Radiation Detection Using n-Type 4H-SiC Epitaxial Layer Surface Barrier Detectors

Abstract: While CdZnTe (CZT) is one of the best materials for room-temperature radiation detection, they are not quite suitable for high-temperature or harsh-environment applications. This chapter discusses the fabrication and characterization of high-resolution 4H-SiC epitaxial detectors, which are appropriate for use in harsh environments like high temperature, chemically reactive and corrosive environments, and most importantly high-dose nuclear radiation environments. Schottky barrier diodes on thin (≤20 μm) 4H-SiC epitaxial layer detectors have been found to be a very promising device for charged particle detection at room and elevated temperatures. While such thin epitaxial layers are sufficient to stop energetic charged particle like alpha particles, highly penetrating radiations such as X- and γ-rays need thicker epitaxial layers to enable substantial photon absorption. This chapter discusses the fabrication of Schottky barrier radiation detectors in n-type 4H-SiC epitaxial layers with different thicknesses (20, 50, and 150 μm); their characterization in terms of alpha, X-rays, and γ-detection; and evaluation of the factors like deep-level defects which regulate their performance as radiation detectors.

Cost-Effective Lebesgue Sampling Long Short-Term Memory Networks for Lithium-Ion Batteries Diagnosis and Prognosis

Abstract: Diagnosis and prognosis are critical for the safe operation of lithium-ion batteries in avoiding serious damage and economic loss caused by power failure, fire, or explosion. With capabilities in learning the long-term dependencies in battery capacity degradation, long short-term memory (LSTM) network is widely used in the fault diagnosis and prognosis (FDP) of lithium-ion batteries. However, FDP based on traditional LSTM network in the Riemann sampling framework has heavy demands on computation and training. To address the problem, this article proposes a cost-effective FDP based on Lebesgue Sampling LSTM (LS-LSTM) network. In the proposed method, a Lebesgue time model is developed to describe the fault growth process, which has lower complexity compared with the traditional fault state space model. Based on the Lebesgue time model, the LS-LSTM network is able to implement the FDP of lithium-ion batteries in a unified “as needed” philosophy. The Monte Carlo method is employed to manage the uncertainties of measurement and prognosis. Offline experiments and online experiments on battery capacity degradation are presented to demonstrate the effectiveness of the proposed method. Experimental results and comparison studies show that the proposed method has good performance in terms of accuracy and computation cost and can be applied to many different applications.

Analysis on security-related concerns of unmanned aerial vehicle: attacks, limitations, and recommendations

Abstract: Over time, the use of UAVs (unmanned aerial vehicles)/drones has increased across several civil and military application domains. Such domains include real-time monitoring, remote sensing, wireless coverage in disaster areas, search and rescue, product delivery, surveillance, security, agriculture, civil infrastructure inspection, and the like. This rapid growth is opening doors to numerous opportunities and conveniences in everyday life. On the other hand, security and privacy concerns for unmanned aerial vehicles/drones are progressively increasing. With limited standardization and regulation of unmanned aerial vehicles/drones, security and privacy concerns are growing. This paper presents a brief analysis of unmanned aerial vehicle's/drones security and privacy-related concerns. The paper also presents countermeasures and recommendations to address such concerns. While laying out a brief survey of unmanned aerial vehicles/drones, the paper also provides readers with up-to-date information on existing regulations, classification, architecture, and communication methods. It also discusses application areas, vulnerabilities, existing countermeasures against different attacks, and related limitations. In the end, the paper concludes with a discussion on open research areas and recommendations on how the security and privacy of unmanned aerial vehicles can be improved.