不同能量放射性核素在井型电离室中轴向响应的实验

为了验证井型电离室对不同能量放射性核素溶液轴向响应及其对放射性活度测量的影响,利用CRC-25R型放射性活度计,将~(125)I、~(131)I、~(18)F、~(137)Cs四种不同能量的放射性核素溶液源在井型电离室内沿中心轴向上移动,测量其放射性活度值的变化,得到轴向位置不同处放射性活度计示值与井型电离室底部的参考示值之比的变化规律,分析轴向响应对不同能量放射性核素放射性活度测量的影响。实验结果表明,不同能量放射性核素溶液其井型电离室轴向响应有明显差异,γ射线能量越高,放射性核素的放射性活度示值极大值的轴向位置越接近井底参考位置;对于γ射线能量较低的~(125)I核素,放射性活度示值极大值的轴向位置接近于井型电离室中部,其示值极大值与参考示值的相对偏差达到了8%,而接近井口处位置时放射性活度计示值与井底参考位置的相对偏差仅-2.9%。     

富钙钛锆石型人造岩石固化体的制备现状

富钙钛锆石型人造岩石将放射性核素固定在其晶格中作为晶体的一部分固定起来,大大提高了放射性废物处置的长期安全性,是固化高放射性废物理想的固化介质.对制备得到的性能稳定的富钙钛锆石型人造岩石固化体的研究现状进行了较为全面的综述和评价.     

医用核素活度计的校准方法

医用放射性核素活度计是一种相对测量仪器，但必须对其4州电离室进行严格的能量刻度和放射性活度校准后，才能被赋予计量学性能。因此，医用放射性核素活度计的校准方法是保证放射性核素活度计量值准确和统一的关键技术。[第一段]     

氧化石墨烯及其复合材料对水中放射性核素的吸附

在核能和核技术的快速发展过程及应用中产生了大量放射性废水,其对生态环境会造成潜在的污染,因此对放射性废水处理技术的研究对保护环境有着重要的意义。氧化石墨烯及其复合材料具有比表面积高、官能团丰富、吸附能力强、化学稳定性好等优点,在放射性废水处理领域受到广泛关注。本文综述了近年来有关氧化石墨烯及其复合材料对水中放射性核素吸附的研究现状及进展,介绍了氧化石墨烯及其复合材料对放射性核素的吸附容量、吸附等温模型、吸附热力学、影响因素和吸附机理。最后分析了氧化石墨烯及其复合材料处理放射性核素在辐射稳定性和高吸附选择性等方面面临的问题和挑战,探讨了推动该类材料今后实际放射性废水处理中工程应用的重点研究方向,如完善的产业体系和积极研发相匹配的成套水处理工艺及设备等。     

镅的电沉积——电镀制源

根据电镀原理进行放射性核素电沉积已经广泛应用于核工业领域,通过电沉积制作α放射性电镀源在计量工作中也起到了不可替代的作用。这种制源方法在特定条件下可以做到定量沉积。此技术的主要影响因素和技术指标包括沉积电流的控制、电镀溶剂的选择、放射性核素最佳质量控制以及电沉积时间的选定。     

金属有机骨架材料在放射性核素去除中的研究

核能利用的过程中, 从铀矿开采、核燃料加工、核能发电到乏燃料后处理, 会产生大量放射性废物, 部分放射性核素会不可避免的释放到环境中, 对环境和人类健康造成重大危害。放射性核素的高效去除是核电健康发展的重要关键科学问题之一。近年来, 高化学稳定性、具有大量功能基团而且结构可调的多孔金属有机骨架材料(MOFs)在放射性污染治理方面受到国内外同行的高度关注。本文系统地介绍了MOFs及MOFs复合材料在放射性核素吸附去除方面的研究进展, 通过宏观吸附、模型分析、先进光谱表征和理论计算四个方面描述放射性核素与MOFs材料的界面作用机理, 并对MOFs材料的吸附性能与其它材料进行对比, 评价MOFs材料在放射性污染治理中的应用前景。     

隐形杀手,你躲得了吗?——谈建材产品的放射性

随着科学技术的进步,人民生活水平的提高,近年来建材放射性问题引起世界各国的广泛关注和高度重视.我国也于今年出台了<建筑材料放射性核素限量>新标准.为了更好地维护我人们的居住环境,确保身体健康,有必要了解一些放射性知识.     

固定式a、β个人表面污染监测装置表面发射率响应的测量

固定式a、β个人表面污染监测装置主要应用于核电站，放射性核素生产等涉源单位，是辐射工作人员从热区进入冷区的必经装置。固定式a、β个人表面污染监测装置的表面发射率表征了该装置的主要性能，是评价该类装置能否正常工作的主要参数依据。本文介绍了用a、β标准平面源测量表面发射率响应的方法与结果，提供了对固定式a、β个人表面污染监测装置性能的评价依据。     

膜分离在放射性废水处理中的应用

由核设施产生的放射性危害是众所周知的,采用各种分离技术来浓集放射性核素,防止其向环境扩散。综述了膜分离技术在放射性废水处理中的最新进展,主要包括微滤(MF)、超滤(UF)、纳滤(NF)、膜蒸馏(MD)、反渗透(RO)、支撑液膜(SLM)等方法。     

用液体闪烁4πβ计数器测量~(134)Cs溶液的活度

引言用液体闪烁计数法测量放射性核素溶液的活度是一种比较精确的方法。该方法的主要优点是: (1)由于放射源与闪烁液均匀混合,无需作源自吸收的修正,故可测量高载体浓度的放射性溶液; (2)几乎可对所有的放射性核素进行测量; (3)制源快速且简单,并可避免升华和吸湿引起的误差; (4)一些修正通过外推到零能量而自然消失。我们这套测量装置已对β放射性核素溶液     

Ecological assessment: an initial evaluation of the ecological input in environmental impact assessment reports in Bahrain

Ecological assessment forms a fundamental part of environmental impact assessment. The quality of ecological input in 15 Bahraini EIA reports concerning coastal and marine developments produced between 1996 and 2004 was evaluated using adopted criteria. The overall quality indicated that eight reports were assessed as borderline quality, and seven reports were found to be of poor quality. Major shortcomings included limited new ecological surveys, inadequate evaluation of impacts, neglecting cumulative and long-term impacts, and failing to address adequately mitigation and monitoring measures.     

结构强震观测与评估研究现状与展望

结构强震观测系统是揭示工程系统抗震行为、评估结构灾后安全性能的一项重要技术,在世界范围内得到了广泛的发展与应用。介绍该观测系统的组成及历史发展,统计国内外典型建筑结构强震观测实例,并分析现有结构强震观测系统的局限性。阐述了强震观测到安全评估的内在逻辑,在此基础上,对Van Nuys酒店长期服役状态与性能评估中的数据挖掘方法进行了综述,并深入分析了当前数据研究与评估方法存在的问题。结合现有国内外研究现状与发展趋势,对未来工程结构强震观测数据的分析挖掘与安全评估进行了展望。     

大型船用齿轮箱长效储存技术

目的 确保大型船用齿轮箱在储存10年后,除寿命件外其余零部件的功能和性能技术状态良好.方法 通过分析传统储存技术的不足和整机长效储存的特点,借鉴新型封闭防锈技术和监控技术,采用分类处理的方式,针对不同系统,采用迷彩高阻隔的柔性防潮材料形成密闭空间、利用油溶性气相防锈油,以及利用不同材料的试片实时监控等新型长效储存技术,使齿轮箱长效储存状态良好.结果 针对零件、整机、分包装监控,使得齿轮箱在长效储存后技术状态良好,齿轮箱整机或零部件可以随时作为备件使用.结论 大型船用齿轮箱长效储存技术有助于大型船用齿轮箱长期可靠储存.     

Human performance reliability: on-line assessment using fuzzy logic

This paper presents an on-line approach to monitoring human performance in terms of conditional reliability when one is performing a task. Unlike traditional human reliability analysis, this approach develops a dynamic model that is able to cope with constantly changing conditions that affect operator performance. A fuzzy knowledge-based assessment approach is developed in order to deal with uncertainty and subjectivity associated with human performance assessment. This technology includes three main parts/functions: (i) on-line performance monitoring; (ii) real-time performance forecasting; and (iii) performance reliability assessment. The technology is demonstrated in real-time and provides timely conditioned reliability information regarding task success/failure. In general, this technology offers human reliability assessment under highly dynamic circumstances.     

The determinants of virtual reality adoption for marine conservation

Initiatives for marine conservation are funded by revenue from marine sites. However, the emergence of COVID-19 has restricted travelling, thus leading to decreased revenue and weakening conservation efforts. Virtual reality technology to support marine conservation efforts is explored as it allows users to experience marine sites, without having to be there physically. This study examines factors influencing users' desire to adopt virtual reality technology in marine ecotourism. With the integration of Stimulus-Organism-Response framework and three behavioural theories (i.e. health belief model, attitude, and eTrust), a hypothetical model was constructed to investigate consumers’ intention to adopt virtual reality technology in marine ecotourism amidst the pandemic. The data were analysed and interpreted using structural equation modelling after 451 survey responses were obtained via an online questionnaire. Outcome expectation, perceived susceptibility, perceived severity, self-efficacy, and cues to action exhibit significant positive effects on attitude towards virtual reality technology in marine ecotourism. Consequently, attitude has a direct and indirect influence on use intention via eTrust. Post hoc analysis revealed that self-efficacy has a direct impact on eTrust and use intention. Total effect analysis further concluded that attitude has the greatest influence on use intention of virtual reality technology in marine ecotourism. This research contributes to the existing literature by utilizing health belief factors to explain use intention of technology towards marine conservation efforts. Recommendations including policy formulation and marketing initiatives were generated for marine ecotourism operators and policymakers.     

Environmental management plan for port and harbour projects

Port activities can cause deterioration of air and marine water quality in the surrounding areas due to multifarious activities. Hence, for the determination of levels of pollution, identification of pollution sources, control and disposal of waste from various point and non-point sources and for prediction of pollution levels for future, regular monitoring and assessment are required during the entire construction and operation phase of a major port. It is extremely essential that port and harbour projects should have an environmental management plan (EMP), which also incorporates monitoring of air and marine water quality along with the collection of online meteorological data throughout the life of the project. This paper presents the environmental impacts due to various port activities and their sources and also discusses the EMP for different pollution prevention, protection and control measures.     

The monitoring of tap waters in Milano: planning, methods and results

The radiometric monitoring of tap waters has been carried out, in Northern Italy, since late the 1980s as part of the activities headed by the National Surveillance Network on environmental radioactivity. Measurements were accomplished by gamma spectrometry over large samples of water that were drained in a single place and concentrated by ion exchange resin treatment. More recently a regular, periodical monitoring was started using liquid scintillation measurements. In this manner, gross alpha and beta activities, uranium, (226)Ra and (222)Rn concentrations are determined at present. Nevertheless, a single-point sampling may be not fully representative of the whole Milano aqueduct, significantly extended and fed by a number of wells. As a control, an extended monitoring of the aqueduct was planned and variations of water radioactivity in different Milano areas have been assessed.     

船用高强钢焊接技术的研究现状与展望

船用高强钢焊接技术是当下造船行业中的重要技术之一,高效、优质的船舶焊接技术已成为船舶工业制造产业长期战略的关键因素。从船用高强钢传统焊接技术、高效电弧焊接技术、高效新型焊接技术等方面介绍了船用高强钢焊接技术的研究现状,重点讨论了船用高强钢焊接技术的细分领域现状,分析了船用高强钢焊接技术的发展趋势。研究表明,船用钢板的板厚朝着厚板、大厚板方向发展,船用钢板的强度朝着高强度、超高强度方向发展,国内外船用高强钢焊接技术相差不大,高效混合焊接技术、高新焊接技术是未来船用高强钢焊接技术的研究热点。     

氨氮在线监测仪示值误差测量值的不确定度评定

随着国家对环境预警监测能力建设投入的加大以及地表水质监测技术的日趋成熟,氨氮在线监测仪在水质自动预警监测系统中得到了更为广泛的应用。为了确保氨氮在线监测仪量值的准确性和一致性,必须采用有效的手段对其量值进行溯源。本文在给出氨氮在线监测仪示值误差数学模型的基础上,对氨氮在线监测仪进行标准不确定度分量的A类评定和B类评定,在B类评定中综合考虑了稀释定容过程引入的不确定度、稀释取液过程引入的不确定度以及氨氮标准溶液引入的不确定度。经过合成得出氨氮在线监测仪测量结果的相对扩展不确定度为2.4%,满足氨氮在线监测仪检定要求。     

舰船柴油机组状态监测及减振效能在线评估系统

主动隔振技术是一种具有治理舰船低频噪声潜力的新技术。针对舰船柴油机组主动隔振试验系统试验时间长、现场混乱、噪声大以及局部有限控制点信息无法进行全局减振效能评估的缺点,特研发一套柴油机组状态监测及减振效能在线评估系统。该系统具有状态在线监测、减振效能在线评估、数据采集和记录以及试验现场视频监控等功能,现场试验显示该系统可以节省时间,提高试验工作效率和工作舒适度,达到预期设计的目的和效果。