排序方式: 共有13条查询结果,搜索用时 649 毫秒
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苯基荧光酮光度法测定·OH 总被引:1,自引:0,他引:1
建立了一种新的测定Fenton反应所产生的羟自由基的方法 ,苯基荧光酮 (Phenylfluorone ,简称本芴酮 )与Fenton试剂作用后 ,使其荧光大大降低 ,其最大激发波长和发射波长分别为 50 0nm和 42 0nm ,基于苯基荧光酮在反应前后的荧光变化 ,即可间接地测定羟自由基的产生量。同时 ,通过清除率实验反证了该方法的可靠性 ,利用顺磁共振法测定苯基荧光酮加入前后的波谱变化来进一步证实该方法的正确性。化学测定过程均在国产仪器下完成 ,具有较高的灵敏度。可推广为一种作为寻找羟自由基清除剂的方法 ,也可作为医学上部分药品性能检验的一种方法 相似文献
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Influence of Positive Bias on Electrical Properties of Undoped Nanocrystalline Diamond Films 下载免费PDF全文
By means of electron assisted hot filament chemical vapour deposition technology, nanocrystalline diamond films are deposited on polished n-(100)Si wafer surface at I kPa gas pressure. The deposited films are characterized with a Raman spectrometer, atomic force microscope, semiconductor characterization system and Hall effect measurement system. The results show that, when bias current is larger than 2 A, sheet hole concentration can increase to a value greater than 1013 cm-2 and undoped nanocrystalline diamond films with a p-type semiconducting characteristic form. Heterojunction between n-Si substrate and the nanocrystalline diamond films deposited with 2 A and 6 A bias current has an evident junction effect. Hole formation mechanisms in the films are discussed. 相似文献
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水杨基荧光酮荧光法测定钴(II)—过氧化氢系产生的羟自由基 总被引:1,自引:1,他引:0
本实验发现Co^2 与H2O2反应生羟自由基的产率比Fenton试剂的高100倍以上,采用水杨基荧光酮(salicyfluorone,SAF)-Co(II)-H2O2荧光法测定羟自由基的新体系,激发波长和发射波长为510nm和500nm,测定体系在反应前后的荧光变化,可间接测定羟自由基产生量,此法不需昂贵的仪器设备,方法灵敏,操作简单易行,清除率实难及ESR波谱法检测证明了该方法的准确可靠,对于医用筛选抗羟自由基药物及抗羟自由基机理研究等方面应用价值. 相似文献
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H2O2—Co^2+产生的羟自由基的溴邻苯三酚红氧化法检测 总被引:11,自引:0,他引:11
提出了Co^2 -H2O2-溴邻苯三酚红分析新体系并用于羟自由基的测定。该法用Co^2 与H2O2反应,类似Fenton试剂产生羟自由基(.OH),并加入溴邻苯三酚红显色剂,使溴邻苯三酚红的颜色发生变化,采用紫外-可见分光光度法测定其△A值的变化,可间接测定羟自由基的产生量。通过测定条件的研究,得出最佳实验条件。结果表明,该法稳定性好,操作简便,测定快速,可作为一种简便的筛选抗氧化剂的方法。 相似文献
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Effect of Gas Pressure on Nanocrystalline Diamond Films Prepared by Electron-Assisted Chemical Vapour Deposition 下载免费PDF全文
With use of electron-assisted chemical vapour deposition (EACVD) technology, nanocrystalline diamond films are successfully deposited on an α-SiC single phase ceramics substrate by means of reduction of the reactive gas pressure. The structure and surface morphology of the deposited films are characterized by Raman spectroscopy, x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The results examined by FE-SEM and AFM show that when the gas pressure was reduced to 0.5- 1 kPa, the surface grain size and surface roughness of the diamond film are decreased greatly to 18-32nm and 34-58nm respectively. The grain sizes estimated from full with at half maximum of (111) XRD peak by the Scherrer formula are 6-28 nm. However, too high secondary nucleation rate may result in pores and defects in the deposited films. Only at suitable gas pressure (1 kPa) to deposit films can we obtain densification and better quality nanocrystalline films. 相似文献