Silicon
nitride (SiN) mechanical resonators with high quality mechanical
properties are attractive for fundamental research and applications.
However, it is challenging to maintain these mechanical properties
while achieving strong coupling to an electrical circuit for efficient
on-chip integration. Here, we present a SiN drum resonator covered
with an aluminum thin film, enabling large capacitive coupling to
a suspended top-gate. Implementing the full electrical measurement
scheme, we demonstrate a high quality factor ∼104 (comparable to that of bare drums at room temperature) and present
our ability to detect ∼10 mechanical modes at low temperature.
The drum resonator is also coupled to a microwave cavity, so that
we can perform optomechanical sideband pumping with a fairly good
coupling strength G and demonstrate mechanical parametric
amplification. This SiN drum resonator design provides efficient electrical
integration and exhibits promising features for exploring mode coupling
and signal processing.
Dragon's blood (DB) possesses great medicinal values due to the presence of several phenolic compounds. This study was designed to investigate the effects of DB and its extracts (DBEs) on oxidative stress in mice exposed to whole body 60Co-γ irradiation (4 Gy). DB and DBEs were intragastrically administered to mice for 5 d prior to radiation. The antioxidant activities, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels in liver and spleen were measured using kits. Furthermore, DB and DBE effects were determined by organ indices and histology of liver and spleen. Our results indicated that the DB and DBE-treated groups showed a significant decrease (P < 0.05) in levels of MDA in liver and spleen compared with the irradiation-only group. Moreover, the activity of SOD, CAT and the level of GSH in liver and spleen tissue were enhanced significantly (P < 0.05) in the DB and DBE groups. DB and DBE also had a significant effect on the recovery of thymus indices. The histological observations of groups having treatment with DB and DBE indicated significant reduction in the radiation-induced damage to the liver and spleen, together with improvement in the morphology of the liver and spleen. These results suggest that DB and DBE treatment prevents radiation-induced oxidative stress injury and restores antioxidant status and histopathological changes in the liver and spleen, but there is need for further study to explore the precise molecular mechanism and strategy for optimal practical application of DB and DBE.
Aimed at the bottleneck of Firework Algorithm's performance and the problem that it is easy to fall into the local extremum, this paper introduces a chaotic map approach and analyzes its statistical characteristics. New hybrid chaotic systems and a chaotic perturbation operator are designed. Based on different chaotic map approaches, a new Chaotic Firework Algorithm (CFWA) is proposed and simulated by typical test functions. The results show that performance of the Chaotic Firework Algorithm is generally better than the original algorithms, and the chaotic hybrid approaches are superior to single chaotic approaches. In order to further verify the application of the proposed algorithm in practical engineering problems, CFWA is applied to Blind Source Separation (BSS) of radar signals. As a result, it does well in sorting observed signals, and has faster convergence and better sorting performance than the traditional algorithms. In this way, the CFWA extends its engineering application.
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