Investigation of radiation-induced surface activation effect in austenitic stainless steel under ultraviolet and γ-ray irradiations

The radiation-induced surface activation (RISA) effect will be applied to the core design in supercritical light water reactor (SCWR) in order to achieve a high performance with excellent economy and safety. The purpose of the present study is to investigate the RISA effect in the candidate fuel cladding materials in SCWR such as PNC1520. The change of weldability due to RISA effect and the related microstructure analysis were performed in oxidized PNC1520 and 304 stainless steel with various oxidization periods. The phases contained in the surface oxide layer of the present specimen were identified as Fe₂CrO₄, γ-Fe₂O₃, and Fe₂O₃. The lifetime of 13.8 days for wettability improving factor was confirmed in the ultraviolet (UV) irradiation. Meanwhile, the long life of 13.8 days and short life of 0.8 days for wettability improving factors were identified in the γ-ray irradiation. Based on the fact that the band gap energies of Fe₂CrO₄, γ-Fe₂O₃, and Fe₂O₃ were, respectively, 2.1, 2.0, and 2.2 eV, and the photo energies of UV and γ-ray irradiation were 4.48 eV and 13.3 MeV, it is therefore clarified that the hydrophilization on the oxide layer is ascribed to the RISA effect.     

基于衰变链计算的裂变产物缓发γ能谱分析

在军控核查技术中,缓发γ能谱是核材料的“指纹”。为计算和分析铀裂变产物的缓发γ能谱,本文将各种类型的衰变链简化为基态线性链和激发态线性链,推导了零时前后各级核素数目的变化公式,建构了计算缓发γ射线能谱的C语言程序代码,并通过实验对理论推导进行了验证。通过分析几种核素的缓发γ射线计数发现,计算结果与实验数据吻合较好。     

基于缓发γ能谱测量的铀丰度分析

本文以加速器驱动的脉冲中子源为照射源、铀材料为照射对象、HPGe探测器为主要探测器,测量得到了铀材料的缓发γ实验谱,再根据理论计算程序和蒙特卡罗方法得到了缓发γ计算谱。结果显示,实验谱和计算谱吻合较好,表明缓发γ能谱测量可作为铀丰度分析的一种技术手段。     

蒙特卡罗模拟矿石品位仪若干测量特性

矿石品位仪主要利用电子对湮灭效应测量较高原子序数金属的含量多少,影响矿石品位仪测量效果和精度的因素有很多。本文主要利用蒙特卡罗模拟方法分析伽玛探测器安装位置对矿石品位仪测量效果的影响,并比较了Ra-226和Co-60两种伽玛放射源应用到矿石品位仪的测量效果差异。     

Inactivation of Enterobacter sakazakii in infant milk formula by gamma irradiation: determination of D10-value

ABSTRACT:  Enterobacter sakazakii is an emerging foodborne pathogen that has caused several cases of meningitis and necrotizing entercolitis in infants and has been associated with infant formulas. Five strains of E. sakazakii were inoculated individually into brain heart infusion broth and rehydrated or dehydrated infant milk formula and exposed to ionizing radiation. E. sakazakii strains in brain heart infusion broth and rehydrated infant milk formula (RIMF) were exposed to irradiation dose of up to 1 kGy while strains in dehydrated infant milk formula (DIMF) were exposed to irradiation dose of up to 9 kGy. The D₁₀-values were determined by using a linear regression model. Average calculated D₁₀-values ranged from 0.21 to 0.29 kGy, 0.24 to 0.37 kGy, and 1.06 to 1.71 kGy in brain heart infusion broth, RIMF, and DIMF, respectively. The results obtained from this study will be useful for powdered infant milk formula industries to reduce the risk associated with E. sakazakii .     

岩屑自然伽马录井技术研究及应用

如何解决PDC钻头钻井条件下岩屑细碎甚至呈粉末状给岩屑录井带来的困难已成为录井行业急待解决的问题。该文作者结合录井工作实践,大胆借鉴有关测井理论,提出了一种全新录井技术岩屑自然伽马录井技术;阐述了岩屑自然伽马录井理论与实验方法,给出了具体实验数据和结果,并与电测数据进行了对比。通过实践表明,该岩屑自然伽马录井方法与电测自然伽马相比具有较好的一致性,对于今后解决细碎岩屑录井识别岩性问题,提供了理论依据,且增加了岩屑录井识别岩性的手段。     

利用测井资料确定页岩储层有机碳含量的方法优选——以焦石坝页岩气田为例

国内外利用测井资料计算页岩储层有机碳含量的方法众多,但各种计算方法都有其相应的适用性及计算精度的优劣。因此,探讨各种计算方法的适用性并最终确定页岩储层有机碳含量的区域性经验计算模型就显得尤为重要。为此,以四川盆地焦石坝地区上奥陶统五峰组—下志留统龙马溪组页岩储层为例,在继承和发展前人研究成果的基础上,结合区域地质特征,利用改进的ΔlgR技术、体积密度法、自然伽马能谱法、多元拟合法、体积模型法等分别建立了有机碳含量的计算模型,并利用岩心分析资料对模型进行对比优选,最终确立了体积密度法为区域性经验计算模型。实践证明:改进的ΔlgR技术和自然伽马能谱法计算精度相对较差;多元拟合法和体积密度法的计算成果均能满足精度要求,但体积密度法方法更为简单且适用范围更广。为进一步验证经验模型的普适性,应用该方法对焦石坝页岩气田重点井的总有机碳含量开展测井精细解释评价,并利用岩心实测资料进行精度分析,其有机碳含量测井解释符合率介于90.5%~91.0%。     

套管井自然伽马能谱测井资料的应用分析

自然伽马能谱测井是一种新的测井方法。该文主要针对胜利油田的多个油区的套管井自然伽马能谱测井资料的应用实例进行了分析，指出它在开发过程中对研究管外窜槽、注水层的吸水量、判断水淹层和划分水淹级别、划分储集层和判断储集层性质、划分油层中的泥岩夹层、确定泥质含量及粘土类型等方面的重要作用。在综合其它测井方法后，能对研究储层变化、寻找剩余油分布等提供重要的手段。     

随钻自然伽马刻度装置及量值传递研究

文章提出随钻自然伽马测井仪刻度的必要性和特殊性，给出了刻度装置的设计和量值传递的流程，同时还导出测量及计算方法。     

用测井曲线组合法复查老井

东濮凹陷文、濮、卫结合部有一批老井需要重新认识，复查挖潜。经实践研究发现用自然伽马、中子伽马、感应曲线组合法，即测井曲线重迭和读值交会两种方法配合使用，可以消除测井曲线质量中的各种不利因素，能够快速、直观地判断油（气）水层，为中高含水期复杂小断块油田开发、重新认识油水层，提供了一个新的途径。