分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-04-19
Lu, Yudong
Zheng, Jinxing
Liu, Xufeng
Wu, Huan
Ge, Jian
Xu, Kun
Li, Ming
Liu, Haiyang
Zhu, Lei
Liu, Fei
摘要： The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement, a processthat can be disrupted by various operational factors. A critical parameter for evaluating the temperature marginof superconducting magnets during normal operation is the nuclear heating caused by D-T neutrons. This studyinvestigates the impact of nuclear heating on a superconducting magnet system by employing an improvedanalysis method that combines neutronics and thermal hydraulics.In the magnet system, toroidal field (TF) magnets are positioned closest to the plasma and bear the highestnuclear-heat load, making them prime candidates for evaluating the influence of nuclear heating on stability.To enhance the modeling accuracy and facilitate design modifications, a parametric TF model that incorporatesheterogeneity is established to expedite the optimization design process and enhance the accuracy of the computations. A comparative analysis with a homogeneous TF model reveals that the heterogeneous model improvesaccuracy by over 12%. Considering factors such as heat load, magnetic-field strength, and cooling conditions,the cooling circuit facing the most severe conditions is selected to calculate the temperature of the superconductor. This selection streamlines the workload associated with thermal-hydraulic analysis. This approach enablesa more efficient and precise evaluation of the temperature margin of TF magnets. Moreover, it offers insightsthat can guide the optimization of both the structure and cooling strategy of superconducting magnet systems.
分类： 生物学 >> 生物物理学 >> 细胞生物学 提交时间： 2016-05-11
Zhu, Lei
Yang, Jing-Yu
Dong, Ying-Xu
Liu, Yang
Miao, Feng-Rong
Xue, Hong
Wu, Chun-Fu
Xue, Hong
Xue, Xue
Wang, Yong-Feng
摘要： In Alzheimer's disease (AD), activated microglia invade and surround beta-amyloid plaques, possibly contributing to the aggregation of amyloid beta (A beta), which affect the survival of neurons and lead to memory loss. Phosphodiesterase-5 (PDE-5) inhibitors have recently been shown a potential therapeutic effect on AD. In this study, the effects of yonkenafil (yonk), a novel PDE-5 inhibitor, on cognitive behaviors as well as the pathological features in transgenic AD mice were investigated. Seven-month-old APP/PSI transgenic mice were treated with yonk (2, 6, or 18 mg/kg, intraperitoneal injection (i.p.)) or sildenafil (slid) (6 mg/kg, i.p.) daily for 3 months and then behavioral tests were performed. The results demonstrated that yonk improved nesting-building ability, ameliorated working memory deficits in the Y-maze tasks, and significantly improved learning and memory function in the Morris water maze (MWM) tasks. In addition, yonk reduced the area of A beta plaques, and inhibited over-activation of microglia and astrocytes. Furthermore, yonk increased neurogenesis in the dentate granule brain region of APP/PSI mice, indicated by increased BrdU(+)/NeuN(+) and BrdU(+)/DCX+ cells compared to vehicle-treated transgenic mice. These results suggest that yonk could rescue cognitive deficits by ameliorated amyloid burden through regulating APP processing, inhibited the over-activation of microglia and astrocytes as well as restored neurogenesis. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
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