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Iron oxide (Fe3O4) pyramid nanostructures were synthesized via a co-precipitation method, without using surfactants or template, for photocatalytic and photoelectrocatalytic activities. The as-made Fe3O4 was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV-vis spectroscopy, photoluminescence spectroscopy, N2 adsorption-desorption analysis, and X-ray photoelectron spectroscopy (XPS). The data clearly demonstrate that the Fe3O4 nanostructures display excellent crystallinity, uniform morphology with a Brunauer-Emmett-Teller (BET) surface area of 52.95 m2 g−1, and an optical bandgap of 2.17 eV, which allows them to serve as outstanding catalysts under visible irradiation. The highest photocatalytic activity of ~ 97% was achieved in the degradation of rhodamine B under visible irradiation, with a degradation rate constant of 0.0322 min−1 at room temperature. Further, electrochemical studies demonstrated that the Fe3O4 electrode possesses good electrocatalytic activity in 0.1 M KOH electrolyte. The highest photocurrent density of 1.2 × 10−4 mA cm−2 was observed in the water splitting reaction. The Fe3O4 nanostructures exhibited superior performance in terms of both dye degradation and photoelectrochemical activity. [ABSTRACT FROM AUTHOR]

A composite-antenna-structure covering three bands of global positioning system (1.575 GHz), digital multimedia broadcasting (2.62 GHz) and direct broadcast satellite (11.7–13.5 GHz) was designed and fabricated as a part of the structure surfaces. A new concept of antennas integrated into a composite sandwich structure provides a design that is an electrically and structurally effective multi-functional antenna structure. We designed two types of antennas. One is an annular ring patch antenna for global positioning system and digital multimedia broadcasting. The other is a microstrip patch antenna for direct broadcast satellite. In the design process, the effects of the composites and adhesive films are considered for in the design processes, because structural materials affect the antenna performance. Additionally, the composite-antenna-structure was designed by considering the coupling effect in a strict substrate. The measured results of buckling tests have provided useful information regarding not only the compression behavioral characteristics but also its degradation in electrical performance before and after the test. The experimental results have shown good results for compressive tolerance, though the specimens after compression loading returns to their original shape before failure. Additionally, an acoustic emission system is implemented in the buckling test system to study the inner behavior of the composite-antenna-structure for the reliability of secure mechanical performance. The antenna performance, as measured by the return loss and radiation pattern, remained excellent after the compression tests. These electrical performance results suggest that antennas with composite laminates will function well despite damage. [ABSTRACT FROM PUBLISHER]

Here we design, fabricate, and study a composite-antenna-structure (CAS) with excellent electrical and mechanical properties. The CAS, consisting of a glass/epoxy face sheet and a honeycomb core, acts as a basic mechanical structure in which a spiral type antenna is embedded. To increase the signal intensity, a carbon fiber plate is used as the bottom sheet. This reflector interrupts radiation, causing the wave from the antenna source to flow to the end of the arms without sufficient radiation. To overcome this problem, a microwave absorber is used for unwanted radiation to reduce the effect of the reflector. We measured the antenna performance by the return loss, axial ratio, gain, and radiation pattern. The structure showed a bandwidth of 0.5–2 GHz and a gain of 5–9 dBi, with circular polarization characteristics and a reflection loss below −10 dB within the desired frequency band. [ABSTRACT FROM AUTHOR]

Introduction: While abnormal responses to threat, including overgeneralization to conditioned fear, have been postulated to play a critical role in pathological anxiety, the relevance of previous findings to social anxiety disorder (SAD) is unclear. We investigated conditioned and generalized fear responses in patients with SAD using socially relevant stimuli., Methods: A total of 26 patients with SAD and 25 healthy controls participated in a fear conditioning and generalization paradigm consisting of two neutral faces as conditioned stimuli (CS+ or CS-) and an angry face with contemptuous comments as unconditioned stimuli. Eight morphed faces of two conditioned stimuli in each continuum were given to test generalization. Behavioral data and physiological responses were acquired., Results: Successful conditioning was observed in the risk ratings for both groups, while only a marginal indication of conditioning was noted in physiological measures. During the generalization phase, patients rated the risk higher than CS- when the stimuli close to CS- contained a portion of CS+ features. Larger skin conductance responses to this stimulus were linked to higher fear of negative evaluation. In addition, patients spent a longer time evaluating safe and ambiguous stimuli than healthy controls and exhibited consistently high levels of subjective arousal., Discussion: Taken together, our findings suggest that SAD patients may exhibit a tendency towards overgeneralization of fear responses and show distinct patterns in processing generalized threat stimuli compared to healthy controls. Even though overgeneralization was not evident in physiological measures, it is necessary to consider this behavioral characteristic in the clinical management of patients with SAD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lee, Lee, Kim, Kim, Jeong, Kim, Glotzbach-Schoon and Choi.)