نتایج جستجو برای: ایزوتوپ 210 pb و cs 137
تعداد نتایج: 852578 فیلتر نتایج به سال:
In this study, a simple one-step hydrothermal reaction is developed to prepare composite based on Prussian blue (PB)/reduced graphene oxide foam (RGOF) for efficient removal of radioactive cesium ((137)Cs) from contaminated water. Scanning electron microscopy and transmission electron microscopy show that cubic PB nanoparticles are decorated on the RGO surface. Owing to the combined benefits of...
Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and (137)Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary sta...
A detailed and comprehensive map of the distribution patterns for both natural and artificial radionuclides over Antarctica has been established. This work integrates the results of several decades of international programs focusing on the analysis of natural and artificial radionuclides in snow and ice cores from this polar region. The mean value (37+/-20 Bq m(-2)) of (241)Pu total deposition ...
Cesium radioactive isotopes (134Cs and 137Cs) are dangerous to human health due to their long half-life and high solubility in water. Nuclear experiments, wars, and nuclear plant accidents have been the main sources of Cs release into the environment. In recent years, several methods have been introduced for the elimination of Cs radioactive isotopes from contaminated wate...
فرسایش خاک تهدیدی جدی برای زندگی بشر میباشد. از اینرو استفاده از روشهای مناسب جهت ارزیابی میزان فرسایش و رسوبگذاری و همین طور اجرای برنامههای حفاظت خاک امری ضروری است. از رادیونوکلوئیدهای ریزشی از قبیل بریلیم-7 (Be7)، سرب-210 (Pb210) و سزیم-137...
Reliable sedimentation histories are difficult to obtain in sandy or anthropogenically impacted coastal systems with disturbed sediment profiles and low initial radionuclide activities. This study addresses the problem using radionuclides in sediment cores from Naples Bay estuary, Florida, USA. Non-steady sedimentation and nuclide scavenging processes are shown to limit application of tradition...
湖泊沉积记录研究对了解流域侵蚀、揭示区域气候环境变化及人类活动影响、建立外生地球化学循环模式等均具有重要意义.放射性同位素210Pb和137Cs组合定年法是百年尺度湖泊沉积记录研究的首选方法，在过去几十年中得到了广泛应用，大力推动了湖泊沉积记录的高分辨率气候环境变化研究的开展.然而，如何理解和选择适用的计算模式来尽可能地提高定年准确度目前仍存在争议，这在一定程度上限制了该方法的应用.鉴于上述问题，本文基于本实验室近年来从青藏高原获取的若干支代表性湖芯的定年结果，从样品前处理、仪器及测试、数据分析及计算等全过程对210Pb、137Cs定年原理和方法进行了较为系统的阐述；在此基础上，提出了210Pb定年样品封装原则，探讨了高纯锗γ谱仪在放射性活度测量中的影响因素，并建立了准确有效...
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