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劳伦斯利弗莫尔和劳伦斯伯克利国立实验室的研究工作者们正在发展一项激光荧光技术,用该技术能够探测贮存的核反应堆废物的渗漏。利弗莫尔的Fred.P.Milanovich认为:该技术在鉴定和测量浓度低到10^-18克分子的锕系(包括铀、钚、镅)元素时,比任何其它的检测方法要灵敏“几千倍”。 相似文献
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基于激光诱导荧光原理研制出一套激光诱导荧光探测气溶胶的装置。该装置采用Nd:YAG脉冲激光器产生355 nm波长脉冲激光,经过引导后进入样品池,激发出的荧光被系统收集后进入高分辨率光栅光谱仪,得到样品的荧光光谱图。选用还原型辅酶I(NADH)和核黄素两种典型的生物荧光物质对系统的性能进行测试,在355 nm激光激发下,获取了还原型辅酶I(NADH)、核黄素荧光光谱图;研究了样品浓度对于荧光光谱强度的影响,结果表明在低浓度范围荧光强度与浓度呈线性关系;考查了激光能量对荧光强度的影响,在一定能量范围荧光强度与激光能量呈线性关系,但当激光能量达到一定值后荧光强度会发生饱和。该装置所建立的生物性物质荧光数据库有利于了解和掌握生物荧光特性,对于进一步实现生物气溶胶远距离探测具有重要意义。 相似文献
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水体可溶性有机物(也叫黄色物质,CDOM),直接影响水体光学特性和遥感光谱特征,在水体生态系统、光学遥感、海洋碳循环中都发挥重要的作用。针对现有水体黄色物质(CDOM)常规测量需要对水样进行过滤等耗时耗力预处理过程,研制了一种水体黄色物质快速测量的可用于实验室及野外分析的激光诱导荧光仪,该仪器集成了405 nm激光激发、高光谱接收和特征荧光光谱解析技术,使得激光雷达能够从各种成分的叠加信号中分离和确认出特定组分。此外,在实验室测量和分析了温度对于CDOM荧光光谱的影响,并提出了一种荧光数据的温度校正算法。该仪器在中国东海2013年4月的测量结果与常规仪器测量结果具有显著的相关性(R2=0.83),揭示了激光诱导荧光技术在CDOM实时监测上的应用潜力。 相似文献
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基于激光诱导荧光原理搭建了用于机动车尾气测量的羟基(OH) 自由基总反应性直接测量系统(LP-LIF-kOH), 并开展了典型柴油车尾气的转鼓测试, 获得了不同排放水平下重型柴油车尾气OH 自由基总反应性的特征。该系统使用中心波长为266 nm的紫外脉冲激光在流动管中光解臭氧产生过量OH 自由基, 使其与采样进入流动管中的活性气体反应发生浓度衰减; 利用中心波长为308 nm 的脉冲激光作为激发光, OH 自由基吸收激发激光能量后释放荧光光子信号, 利用激光诱导荧光技术记录OH 自由基衰减曲线对衰减过程进行测量; 而通过对衰减曲线进行指数拟合, 即可获得采样气的OH 自由基总反应性(kOH)。在柴油车尾气中的活性有机物闭合测量实验中, 对国三与国五的柴油车尾气进行kOH 的测量, 发现柴油车尾气kOH 的值随着国家排放标准的升高而降低, 不同车辆的kOH 差别较大, 同一车辆冷启动测得的kOH 值大于热启动测得的kOH 值。kOH 的主要贡献来自氮氧化物(55%)、一氧化碳(2%) 和一次排放的挥发性有机物(34%)。最后初步建立了一种利用kOH 估算柴油车尾气碳氢化合物(HC) 排放因子的方法。 相似文献
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Yaru Cheng Fan Yang Kai Zhang Yiyi Zhang Yu Cao Conghui Liu Huiting Lu Haifeng Dong Xueji Zhang 《Advanced functional materials》2019,29(45)
Here, in terms of the highly reactive oxidative hydroxyl radical (?OH) generation ability of isoniazid (INH) catalyzed by Mn2+ ion and the photothermal effect of WSSe nanoflakes, a WSSe/MnO2‐INH nanocomposite for synergistic anticancer treatment is developed. Advanced INH‐induced ?OH formation ability is systemically demonstrated in the presence of manganese and relevant non‐Fenton‐type mechanism, and good photothermal conversion efficiency of the WSSe/MnO2 nanocomposite. After modifying with mitochondria‐targeted triphenylphosphonium bromide (TPP) moieties and camouflaging with cancer cells membrane (WSSe/MnO2‐INH‐TPP@CM), it confers a sequential cell‐to‐mitochondria targeting ability. In vivo X‐ray computed tomography and magnetic resonance tumor imaging capability of the nanocomposite are also revealed. The mitochondria‐targeted oxidative damage and photothermal therapy by WSSe/MnO2‐INH‐TPP@CM results in excellent anticancer treatment efficacy both in vitro and in vivo. This is the first exploration of the possibility of non‐Fenton‐type ?OH formation for anticancer treatment, which opens new opportunities for ROS‐based and combined cancer treatment strategies. 相似文献
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Disordered Atomic Packing Structure of Metallic Glass: Toward Ultrafast Hydroxyl Radicals Production Rate and Strong Electron Transfer Ability in Catalytic Performance 下载免费PDF全文
Zhe Jia Xiaoguang Duan Peng Qin Wenchang Zhang Weimin Wang Chao Yang Hongqi Sun Shaobin Wang Lai‐Chang Zhang 《Advanced functional materials》2017,27(38)
Developing new functional applications of metallic glasses in catalysis is an active and pivotal topic for materials science as well as novel environmental catalysis processes. Compared to the crystalline materials with highly ordered atomic packing, metallic glass has a simply disordered atomic structure. Recent reports have demonstrated that the metallic glasses are indeed having many superiorly catalytic properties, yet the understanding of the mechanism is insufficient. In this work, the structural relaxation (α‐relaxation) by annealing in an amorphous Fe78Si9B13 alloy is studied for unraveling the catalytic mechanism at the atomic scale. The volume fractions of the crystalline structures, such as α‐Fe, Fe2Si, and Fe2B, in the as‐received and annealed metallic glasses are fully characterized. It is found that the randomly atomic packing structure with weak atomic bonding in the as‐received metallic glass has an efficient electron transfer capability, presenting advanced superiorities in the aspects of production rate of hydroxyl radicals (?OH), dye degradation rate (k ), and essential degradation ability (K SA) for water treatment. The discovery of this critically important work unveils why using metallic glasses as catalysts has higher reactivity than the crystalline materials, and more importantly, it provides new research opportunities into the study of synthetic catalysts. 相似文献
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内部水汽含量检测技术和低压封装限制 总被引:1,自引:1,他引:0
阳辉 《电子产品可靠性与环境试验》2002,(6):22-25
介绍了GJB 548A方法1018规定的内部水汽含量的三种测定程度和原理以及所用的设备,并重点介绍了程度1中的有关测试方法以及对内部封装压强的要求。 相似文献
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用射频噪声法测出了低气压放电灯(荧光灯、紧凑型节能灯、紫外杀菌灯等)阴极的零场发射电流,进而研究了阴极温度和阴极零场发射之间的变化规律,最后,得到了一种比较简单、方便、实用的测试阴极发射特性的方法。 相似文献