核技术利用辐射安全监管法律法规解读

随着核技术日益广泛的利用,我国放射性同位素和射线装置技术的应用发展迅速,它在给人类带来巨大利益的同时也带来了辐射危害,安全隐患突出,安全监管任务重。本文就与核技术利用辐射安全监管有关的问题进行法律法规解读,以提高辐射安全监管依法行政能力。     

Worldwide standards on exposure to electromagnetic fields: an overview

Over the last years, a wide debate has developed on the possible health effects of exposure to electromagnetic fields. In-depth research activity was therefore developed by the international scientific community aimed at evaluating the risk associated with exposure to this type of radiation. At the same time, various international institutions began to issue recommendations on exposure limits valid for workers and for the population in the frequency range up to 300 GHz. Most of the recently revised safety standards worldwide are set in terms of internal rates of electromagnetic energy deposition (Specific Absorption Rate) at radiofrequency and microwave frequencies, and of induced electric fields or current densities at lower frequencies up to 10 MHz. At the international level, the most authoritative guidelines have been developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP); another internationally well recognized standard is that developed by the Institute of Electrical and Electronics Engineers (IEEE) in the USA, adopting the same basic approach of ICNIRP, although with some differences in numerical values. This article is mainly focused on the analysis of different approaches for the protection against electromagnetic fields, and on the rationale of most relevant standards.     

高原气候环境对涂层材料性能的影响研究

太阳辐射是引起有机涂层老化的最主要原因。由于高原拉萨地区的太阳辐射年总量比内地同纬度高出约一倍,分别将3种同基材同镀层但不同底漆和面漆的6类常用防护涂层在高原气候条件下自然暴露试验一年。经过对比,能较快速优选出性能相对稳定的涂层。     

关于我国环境辐射防护标准的几点思考

随着科学技术的进步,环境辐射已成为本世纪的主要污染源之一。本文重点介绍了电离辐射和电磁辐射的防护标准体系,针对它们的特点及不足提出：我国今后制定新的环境辐射防护标准时,应统一环境电磁波容许辐射强度的国家标准,建立相关产品的电磁辐射强度国家标准,制定相关环境辐射防护标准,从而完善辐射防护标准体系,加强环境保护。     

Hydroxycinnamic acid derivatives in an aquatic liverwort as possible bioindicators of enhanced UV radiation

We examined, under laboratory conditions, the physiological responses of the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia to artificially enhanced ultraviolet (UV) radiation for 82 days, especially considering the responses of five hydroxycinnamic acid derivatives. This species lives in mountain streams, where it is exposed to low temperatures and high UV levels, and this combination is believed to increase the adverse effects of UV. Enhanced UV radiation hardly caused any change in several physiological variables indicative of vitality, such as Fv/Fm and chlorophylls/phaeopigments ratio (OD430/OD410). Thus, this liverwort seemed to be tolerant to UV radiation, probably due to the accumulation of three UV-absorbing hydroxycinnamic acid derivatives: p-coumaroylmalic acid, 5'-(7',8'-dihydroxycoumaroyl)-2-caffeoylmalic acid, and 5'-(7',8'-dihydroxy-7-O-beta-glucosyl-coumaroyl)-2-caffeoylmalic acid. These compounds might serve as bioindicators of enhanced UV radiation.     

Increased environmental gamma-ray dose rate during precipitation: a strong correlation with contributing air mass

It has long been observed that the environmental gamma-ray dose rate increases noticeably during precipitation intervals. This increase, due to the presence of radon progeny in the rain droplets (or snow flakes), can affect the reliability of the monitoring of artificial radioactivity and long term estimates of exposure to ambient natural radionuclides in surveillance network. Predicting the amplitude of the dose increase has been shown to be surprisingly challenging. In this work, standard air mass back trajectory analysis is used to show that the amplitude of the increase can be quantitatively linked to the history of the air mass where the precipitation is occurring. Furthermore, we show how back trajectory analysis, environmental gamma and rain data can be used to obtain estimations of relative radon emanation rates for locations far from the actual point of detection.     

DNA碱解旋速率法及其在DNA损伤研究中的应用

对DNA碱解旋速率法的细胞DNA经碱解旋后通过羟基磷灰石(HA)柱分离单、双链DNA时的洗脱次数、温度以及DNA回收效果进行了研究。结果表明,用0.125mol/L和0.25mol/L磷酸钾缓冲液各3ml,先后各洗脱一次,即可满足细胞DNA链断裂研究的要求。洗脱双链DNA时的温度为60℃即可。~3H-DNA与细胞其它组分一起通过HA柱时,~3H-DNA的回收率达94％左右。应用这一技术对电离辐射引起的中国田鼠肺细胞和小鼠脾细胞DNA单链断裂损伤与照射剂量的关系进行了探讨。结果表明,DNA单链断裂程度与照射剂量呈正相关。     

中国北方沙漠戈壁区沙尘气溶胶与太阳辐射的关系

利用中国大陆气溶胶指数(TOMS AI)、天文总辐射、地面太阳总辐射和沙尘能见度等观测和理论计算资料,对中国北方沙漠戈壁区沙尘气溶胶与太阳辐射的关系进行了分析.结果表明:沙漠地区太阳辐射和沙尘气溶胶指数有非常高的相关性,且变化趋势一致.表明由太阳辐射触发的热对流是影响沙漠地区沙尘气溶胶最主要的因子;沙尘气溶胶进入大气中,必然也会对太阳辐射产生重大的影响.晴日时沙尘气溶胶吸收和散射辐射可达沙尘暴(含扬沙)天气时的60%以上.     

淹水与非淹水条件下外源水铁矿和葡萄糖对土壤磷有效性的短期影响

土壤中活性铁氧化物含量及其对土壤磷生物有效性的影响与施用有机肥有关,但外源添加活性铁氧化物和有机物对土壤有效磷含量的影响并不清楚.通过室内培养实验,研究了在淹水和非淹水条件下外源水铁矿和葡萄糖对土壤中植物有效磷(SAP)含量的影响.利用同步辐射红外显微成像技术原位探索了微域内铁和磷的空间关系.研究结果表明,在培养192 h内无论是添加水铁矿或葡萄糖或二者同时添加均会使SAP含量显著下降且呈持续下降趋势.在淹水和非淹水条件下单施水铁矿处理SAP含量分别下降30.9%和25.8%,单施葡萄糖SAP分别下降40.5%和26.8%,而同时施加水铁矿与葡萄糖处理SAP分别下降61.5%和45.3%.因此,同时施加外源水铁矿和葡萄糖对淹水条件下SAP含量影响更大.同步辐射红外显微成像分析结果表明,无论是添加水铁矿还是葡萄糖或二者同时添加,都会通过改变微区内铁和磷的空间分布打破原来土壤中铁磷相互作用平衡.上述研究结果对于土壤磷养分管理和磷面源污染控制具有重要参考价值和应用潜力.     

长江流域鲤鱼和鲟鱼的模型建立与剂量率估算研究

针对长江流域两种典型淡水鱼类-鲤鱼和鲟鱼,通过实验对两种鱼类各部分的浓集性质进行了研究,并建立了相关的的简化解剖学模型(区分了不同组织和器官部分)和外照射环境模型;用蒙特卡罗方法模拟源器官和环境水体对靶器官的能量沉积,采用某厂址水体数据以及实验得到的鱼类不同部位的浓集系数,估算了上述两种鱼类在该环境中所受到的内外照射剂量率,并与ERICA方法进行了比较分析.