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This article is concerned with the inverse eigenvalue problem for rank one perturbations of the Sturm-Liouville operator. I obtain the relationship between the spectra of the Sturm-Liouville operator and its rank one perturbations, and from the spectra I reconstruct the perturbed operators, provided that the potential is known a priori.

Laser-scribed graphene (LSG), a classic three-dimensional porous carbon nanomaterial, is directly fabricated by laser irradiation of substrate materials. Benefiting from its excellent electrical and mechanical properties, along with flexible and simple preparation process, LSG has played a significant role in the field of flexible sensors. This review provides an overview of the critical factors in fabrication, and methods for enhancing the functionality of LSG. It also highlights progress and trends in LSG-based sensors for monitoring physiological indicators, with an emphasis on device fabrication, signal transduction, and sensing characteristics. Finally, we offer insights into the current challenges and future prospects of LSG-based sensors for health monitoring and disease diagnosis. [ABSTRACT FROM AUTHOR]

A phosphoric acid additive with an optimal concentration of 0.1 M can vastly promote the diffusion kinetics of the redox reaction between V(IV) and V(V) without a significant decline in energy efficiency for 300 cycles, and maintain the high-temperature stability (55 °C) of an electrolyte at a high state of charge (SOC) of 70% over the course of 30 days. [ABSTRACT FROM AUTHOR]

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Cognitive radio networks (CRNs) and millimeter wave (mmWave) communications are two major technologies to enhance the spectrum efficiency (SE). Considering that the SE improvement in the CRNs is limited due to the interference temperature imposed on the primary user (PU), and the severe path loss and high directivity in mmWave communications make it vulnerable to blockage events, we introduce an intelligent reflecting surface (IRS) into mmWave CRNs. Due to the estimation mismatch and the passivity of Eavesdroppers (Eves), perfect channel state information (CSI) of wiretap links is challenging to obtain, which promotes our research on robust secure beamforming (BF) design in the IRS-assisted mmWave CRNs. This paper considers the collaborate scenario of Eves, which allows us to investigate the BF design in the harsh eavesdropping environment. Specifically, by using a uniform linear array (ULA) at the cognitive base station (CBS) and a uniform planar array (UPA) at the IRS, and supposing that imperfect CSIs of angle-of-departures for wiretap links are known, we formulate a constrained problem to maximize the worst-case achievable secrecy rate (ASR) of the secondary user (SU) by jointly designing the transmit BF at the CBS and reflect BF at the IRS. To solve the non-convex problem with coupled variables, an efficient alternating optimization algorithm is proposed. As for the transmit BF at the CBS, we propose a heuristic robust transmit BF algorithm to attain the BF vectors analytically. As for the reflect BF at the IRS, by means of an auxiliary variable, we transform the non-convex problem into a semi-definite programming problem with rank-1 constraint, which is handled with the help of an iterative penalty function, and then obtain the optimal reflect BF through CVX. Finally, simulation results indicate that the ASR performance of our proposed algorithm has a small gap with that of the optimal solution with perfect CSI compared with the other benchmarks. [ABSTRACT FROM AUTHOR]

A 3.5 tonne forklift containing proton exchange membrane fuel cells (PEMFCs) and lithium-ion batteries was manufactured and tested in a real factory. The work efficiency and economic applicability of the PEMFC forklift were compared with that of a lithium-ion battery-powered forklift. The results showed that the back-pressure of air was closely related to the power density of the stack, whose stability could be improved by a reasonable control strategy and membrane electrode assemblies (MEAs) with high consistency. The PEMFC powered forklift displayed 40.6% higher work efficiency than the lithium-ion battery-powered forklift. Its lower use-cost compared to internal engine-powered forklifts, is beneficial to the commercialization of this product. [ABSTRACT FROM AUTHOR]

In this research, the features of the Kuroshio Current in 2019 were studied based on the observations of 29 self-developed surface current experiment drifters deployed in the western Pacific Ocean and the East China Sea. The Kuroshio flow pattern and velocity magnitude observed in 2019 were largely consistent with the climatology based on the historical drifter dataset, but they still exhibited distinctive characteristics. The intrusion of the Kuroshio into the South China Sea in the spring was observed by a group of drifters crossing the Luzon Strait from east to west, which is a notable departure from the non-intrusion pattern noted to occur in the spring in most of the historical records. A strong intrusion of the Kuroshio into the East China Sea was also observed, taking an anti-cyclonic turn in the northeast of Taiwan Island. Both the drifter trajectories and altimeter-derived dynamical topography captured the large meander pattern of the Kuroshio south of Japan in 2019, with the flow path having a maximum offshore distance of 470 km. In addition, Lagrangian statistics (lateral diffusivity, integral time scale, and integral space scale) were estimated for four selected regions with adequate drifter samplings. The lateral diffusivity had large values along the Kuroshio segment in the East China Sea and small values on the continental shelf of the East China Sea. The integral time scales for the four regions ranged from 0.8 to 3.7 days, with a corresponding integral space scale of 19~128 km. [ABSTRACT FROM AUTHOR]

This paper is concerned with the inverse eigenvalue problem for singular rank one perturbations of a Sturm-Liouville operator. We determine uniquely the potential function from the spectra of the Sturm-Liouville operator and its rank one perturbations. [ABSTRACT FROM AUTHOR]