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Dongjie CUI 《等离子体科学和技术》2022,24(4):45504
Mung bean (Vigna radiata) sprouts are widely consumed worldwide due to their high nutritional value. However, the low yield and microbial contamination of mung bean sprouts seriously reduces their economic value. This study investigates the effects of non-thermal plasma on the quality and microbial reduction of mung bean sprouts by pretreatment of seeds in water for different times (0, 1, 3 and 6 min). The quality results showed that short-time plasma treatment (1 and 3 min) promoted seed germination and seedling growth, whereas long-time plasma treatment (6 min) had inhibitory effects. Plasma also had a similar dose effects on the total flavonoid and phenolic contents of mung bean sprouts. The microbiological results showed that plasma treatment achieved a reduction of native microorganisms ranging from 0.54 to 7.09 log for fungi and 0.29 to 6.80 log for bacteria at 96 h incubation. Meanwhile, plasma treatment could also efficiently inactivate artificially inoculated Salmonella typhimurium (1.83–6.22 log) and yeast (0.53–3.19 log) on mung bean seeds. The results of seed coat permeability tests and scanning electron microscopy showed that plasma could damage the seed coat structure, consequently increasing the electrical conductivity of mung bean seeds. The physicochemical analysis of plasma-treated water showed that plasma generated various long- and short-lived active species [nitric oxide radicals (NO·), hydroxyl radicals (·OH), singlet oxygen (1O2), hydrogen peroxide (H2O2), nitrate (${{\rm{NO}}}_{3}^{-}$), and nitrite (${{\rm{NO}}}_{2}^{-}$)] in water, thus the oxidizability, acidity and conductivity of plasma-treated water were all increased in a treatment time-dependent manner. The result for mimicked chemical mixtures confirmed the synergistic effect of activity of H2O2, ${{\rm{NO}}}_{3}^{-}$ and ${{\rm{NO}}}_{2}^{-}$ on bacterial inactivation and plant growth promotion. Taken together, these results imply that plasma pretreatment of mung bean seeds in water with moderate oxidizability and acidity is an effective method to improve the yield of mung bean sprouts and reduce microbial contamination. 相似文献
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结合北京地理位置、降雨特点以及山区旅游资源特点,总结山区旅游区多年来历史洪灾和发生频次,通过分析旅游区山洪灾害形成的原因,受洪灾的影响和危害、目前防范工作存在的问题等,提出防范应对策略,特别加强非工程措施完善,确保山区旅游区人员和财产安全. 相似文献
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建立台风信息系统是防御台风的非工程措施之一,根据水务现代业务需求,开发出的系统实现了在信息获取上自动化,信息分析上客观化,用户使用上简单化,系统运行稳定化.其建设的目标是建立一套高效实用的台风监测系统,通过卫星和计算机网络系统,高效和有序地传输数据和进行数据库管理.用户只需通过客户计算机上的浏览器(Internet方式或Intranet方式)调用该程序,就可以查询、显示历史台风和实时台风信息等. 相似文献
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根据北京市近年来形成的平原降雨量多于山区降雨量,城区突发性暴雨频发等降雨特点,提出了建立调度联动工作机制,从过去单一纵向指挥体系发展为纵横交错的联动体系。通过两年多的运用与深化,建立调动联动机制有利于统一指挥,协同作战,形成防汛救灾的工作合力,确保防汛安全。 相似文献
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以北京城市河湖流域为例,分析北京城市河湖流域当前防洪管理现状,包括管理体制、责任制体系、管理职能、工作机制及管理措施等,查找存在的问题和不足,分析防洪管理工作的弊端,从流域角度,提出流域与区域相结合的综合型防洪管理模式,创新制定防洪工程措施体系和非工程措施体系,明确工作职责,制定工作机制,完善防洪管理保障体系等,对提高北京市城市河湖防洪管理工作水平有一定借鉴作用. 相似文献
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对基于平面裁切的乙烯-四氟乙烯(ethylene-tetrafluoroethylene,ETFE)气枕进行充气成形试验,利用激光位移计测量气枕矢高,基于三维摄影测量得到的形状,分析了气枕膜面应力分布。采用Peirce模型模拟ETFE膜材的材料力学非线性并进行相同充气过程的数值模拟,对比分析数值模拟与实测的气枕矢高和应力分布。结果表明:Peirce模型仅在反映ETFE两个屈服点之间的应力-应变关系上有所偏差;气枕充气完成后矢高约为172mm,气枕膜面应力最大值集中于气枕中心与各边中点的连线区域;不同内压下的气枕矢高,膜面应力、应变的数值模拟结果与实测结果相对误差均在10%以内。此外,Peirce 模型数值模拟结果表明,内压为2kPa时气枕膜面出现塑性应变;膜面总应变与塑性应变最大值集中于气枕中心与各边中点连线区域。 相似文献
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