核辐射——勿需害怕,但须小心

<正>2011年3月11日下午,日本东部海域发生里氏9.0级大地震,并引发了海啸。位于日本本州岛东部沿海的福岛第一核电站停堆,几个机组发生了失去冷却剂事故。3月12日下午,一号机组发生了爆炸。3月14日,三号机组发生了两次爆炸。这几次爆炸的发生,改写了世界核安全历史,从而又一次触动了老百姓恐"核"的神经。核辐射究竟是什么?核辐射真的很可怕吗?一、人类所受核辐射的来源本文所说的辐射指核电离辐射。人类所受照射的来源主要有两个方面:一个是天然辐射,另一个是人工辐射,其中天     

环境地表γ辐射剂量率的测量不确定度评定

依据JJF1059.1-2012《测量不确定度评定与表示》方法和原理,对环境地表γ辐射剂量率测量不确定度进行了评定:建立数学模型,分析测量不确定度的来源,得出相对扩展不确定度。     

Photoassisted Fenton degradation of phthalocyanine dyes from wastewater of printing industry using Fe(Ⅱ)/γ-Al2O3 catalyst in up-flow fluidized-bed

Fe(II)/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide(γ-Al2O3) and iron(II)-precursor(FeSO4), and used for photoFenton degradation of phthalocyanine dyes(PCS) under ultraviolet(UV) irradiation in an up-flow fluidized bed. The catalysts were characterized by XRD, ESCA, BET, EDS and SEM. The results showed that Fe2+ion was compounded on the γ-Al2O3 carrier. The effects of different reaction parameters such as catalyst activity, dosage and solution pH on the decolorization of PCS were assessed. Results indicated that maximum decolorization(more than 95%) of PCS occurred with20 wt% Fe(II)/γ-Al2O3 catalyst(dosage of 60 g/L) using a combination of UV irradiation and heterogeneous Fenton system. The degradation efficiency of PCSincreases as pH decreases, exhibiting a maximum efficiency at pH 3.5. The recycled catalyst was capable of repeating three runs without a significant decrease in treatment efficiency, and this demonstrated the stability and reusability of catalyst.     

辐射化学剂量计在强脉冲混合辐射场测定中的应用

本文讨论了将硫酸亚铁剂量计和铜－铁剂量计用于强脉冲混合辐射场测定的实验设计,利用直径２２０毫米的聚乙烯球,将硫酸亚铁剂量计的快中子响应降低到２０％以下,由它和完全暴露在中子、γ混合场中的硫酸亚铁剂量计响应之差,测量中子吸收剂量。这种方法两次实际用于强脉冲混合辐射场中子、γ吸收剂量测量,得到的结果和热释光剂量计、固体径迹探测器的测量结果进行了比较,在±２５％的误差范围内一致     

石油测井用中子源辐射屏蔽研究

放射源测井技术是当今石油勘探和开发中必不可少的手段，开展对测井人员的屏蔽防护研究十分必要。将聚乙（丙）烯与碳化硼和氧化铝等以不同比例混合后制成的板材和织物具有良好的热中子、中能中子和快中子屏蔽效果，加工成屏蔽装置后，可使镅－铍源中子的屏蔽率达到６２．０６％，γ射线屏蔽率达到３２．４３％，结合中子辐射防护服和防护围裙等的使用，可较好地解决测井人员的辐射防护问题。     

催化极谱分析在环境监测中的地位和应用

极谱分析在地质、冶金等部门已广泛应用,有的已作为标准方法,如1982年出版的地质部化探元素标准方法中,铜、铅、锌、钴、镍、钒、铍等元素的催化极谱法受到奖励.其所以能推广应用之主要原因是灵最敏度高,选择性好,快速和准确.在环境监测中,一般测试物质的含量在ppb和ppt级,故选择高灵敏度的分析方法十分必要,从目前很多文献报导,极谱分析属当前仪器分析中     

球罐检验中γ射线源的管理及γ射线的防护

简述了辐射防护的基本方法 ,介绍了使用 γ射线应注意的问题。     

Probing and understanding interaction of Eu(III) with γ- alumina in presenceof malonic acid

Radionuclide migration in aquatic environment is influenced by its sorption onto colloids/mineral oxides and the presence of organic complexing anions. With a view to understand the sorption of trivalent actinides by mineral oxides in presence of organic acid, in the present study, Eu(III), malonic acid (MA) and γ-alumina are considered as representatives of trivalent actinides, low molecular weight natural occurring organic acid and aluminol sites, respectively. The influence of MA on sorption of Eu(III) by γ-alumina was elucidated by batch sorption, spectroscopic techniques and surface complexation modeling, for the first time. Attenuated Total Reflection-Fourier Transform Infrared spectroscopic studies of MA sorbed on γ-alumina revealed the presence of two inner-sphere surface complexes. Batch sorption for binary (alumina-Eu(III)) and ternary (alumina-Eu(III)-MA) systems were investigated as a function of pH, Eu(III) concentration and sequential addition of Eu(III)/MA. The pH edge for Eu(III) sorption shifts to higher pH with increasing Eu(III) concentration. In ternary systems, Eu(III) sorption is significantly enhanced at pH < 4.5. Eu(III) speciation on γ-alumina is independent of addition sequence of Eu(III)/MA. Time resolved fluorescence spectroscopy of Eu(III) sorbed on γ-alumina exhibited two surface species, XOEu²⁺ and (YO)₂Eu⁺. The enhancement in I₆₁₆/I₅₉₂ and lifetime for ternary systems, as compared to binary system, at low pH, indicates the participation of Eu-MA complexes in the formation of surface species in ternary systems. The diffuse layer model has been employed to successfully model the experimental sorption profiles of binary and ternary systems, using code FITEQL 4.0, by considering the surface species identified by spectroscopic techniques.     

同工酶在环境监测中的应用

酶实际上就是具有生物催化作用的蛋白质。生物体内的任何生化反应都离不开酶的催化作用。一个完整的酶分子,有它自己独特的结构,这种结构决定了酶的催化作用,也决定了酶活力大小的调控作用和酶在细胞内部的分布位置。在生物体内有一些酶的催化作用是相同的,但其结构不同。因此,它们往往对底物     

利用数据库技术结合便携式γ谱仪测量土壤中放射性核素的方法

NaIγ能谱仪是定量测量土壤中放射性核素活度的主要仪器,它具有能量响应好、效率高的特点.但是它的解谱软件计算出的结果误差较大,而用手工方法计算又过于繁琐,因此利用数据库进行解谱和计算,不失为一种即准确又快捷新方法.