共查询到20条相似文献,搜索用时 15 毫秒
1.
S. Sato Y. Koike T. Saito J. Sato 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(2):351-353
The atmospheric concentration of 210Pb and 7Be was observed at Sarufutsu on the coast of the Sea of Okhotsuk in Hokkaido, Japan. Measurements were carried out during the period from February to August, 2001. The atmospheric concentrations of 210Pb and 7Be ranged from 0.2 to 2.5 mBq/m3 and from 0.0 to 4.2 mBq/m3, respectively. The seasonal variation pattern of the atmospheric concentration of 210Pb indicated that the air mass from Chinese Continent reached the coast of the Sea of Okhotsuk. 相似文献
2.
To evaluate the radionuclide migration from the atmosphere to the ground surface, atmospheric deposition samples were collected from 1993 to 2001 with a basin set up at Tokai-mura, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a Ge detector for 7Be, 40K, 137Cs and 210Pb. According to the analysis, clear seasonal variations with spring peaks of deposition weight and deposition amounts of all the radionuclides were found. The analysis also showed that these radinuclides can be divided into two groups, each having different carrier particle sizes and, hence, different deposition processes. 相似文献
3.
4.
N. Akata H. Kawabata H. Hasegawa K. Kondo T. Sato Y. Chikuchi S. Hisamatsu J. Inaba 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(2):493-498
Atmospheric concentrations of 210Pb change with various factors such as meso-scale meteorological conditions. We have already reported the biweekly atmospheric
210Pb concentrations in Rokkasho, Japan for 5 years and found that they had clear seasonal variations: low concentrations in
summer and high values in winter to spring. To study the reasons for the seasonal variations, the origins of the air mass
flowing to Rokkasho were analyzed by 3-D backward air mass trajectory analysis. Routes of the calculated trajectories were
classified into four regions: northeastern and southeastern Asian Continent, sea and other regions. The atmospheric 210Pb concentrations were well correlated with the frequency of the routes through the northeastern Asian Continent. A non-linear
multiple regression analysis of the 210Pb concentrations and the relative frequencies of the four routes showed good fitting of the predicted values to the observed
ones, and indicated that the atmospheric 210Pb concentrations in Rokkasho depended on the frequency of the air mass from the northeastern Asian Continent. 相似文献
5.
H. Hasegawa N. Akata H. Kawabata Y. Chikuchi T. Sato K. Kondo J. Inaba 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):171-175
7Be deposition fluxes and atmospheric concentrations were measured at Rokkasho Village, Aomori Prefecture, Japan, from 2000
to 2005. It was confirmed that the 7Be deposition fluxes were minimum in summer, and the fallout maximizes in winter. The atmospheric concentration of 7Be was especially low in summer, and high in the other three seasons. A positive correlation was observed between the amount
of precipitation and 7Be deposition. Clear seasonal differences were evident among the ratios of 7Be deposition flux to precipitation amounts in the four seasons. The ratios were especially high in winter, higher than those
in the other three seasons. 7Be deposition flux was estimated by a simple simulation model using atmospheric 7Be concentrations and local meteorological data. As a result, the estimated deposition value was relatively lower than the
measured value in winter. 相似文献
6.
M. Azahra J. J. López-Peñalver M. A. Camacho-García C. González-Gómez T. El Bardouni H. Boukhal 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(2):401-405
Aerosols samples in near-surface air of Granada (Spain) were collected on a weekly basis. The seasonal 210Pb and 7Be concentrations were determined during the five-year period, from October 1993 to September 1997. The elements, despite their different origin and their different distribution throughout the atmosphere, present the same seasonal variation. There was a tendency for a maximum during the summer season and a minimum during fall and/or winter. In this work, the concentration of 7Be and 210Pb and meteorological data have been used in order to determine the periods of the potential radioactive pollution. This study, also, shows that the deposition of 7Be occurs primarily by precipitation except during the investigation periods where precipitation was scarce and irregular.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
7.
Hu Jufang Sha Zhanjiang Wang Jinlong Du Jinzhou Ma Yujun 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(3):1141-1150
Journal of Radioanalytical and Nuclear Chemistry - First continuous observations of 7Be and 210Pb monthly total depositional fluxes were performed from December 2014 to November 2017 in Xining, a... 相似文献
8.
S. Osaki Y. Tagawa S. Sugihara Y. Maeda Y. Inokura 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(3):449-454
The concentrations of 7Be, 210Pb and 210Po of ca. 60 parts of a whole tree of Japanese cedar and of underlying litter and soil samples were determined for studying their transfer in a forest canopy. The results suggest that the mean residence times of 7Be and 210Pb in the forest canopy were ca. 20 and 900 days, respectively, and the dry deposition rate of 7Be on the forest canopy was about a half of the total deposition rate. 相似文献
9.
Y. Ohtsuka T. Iyogi H. Kakiuchi Y. Takaku S. Hisamatsu J. Inaba 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):625-630
The background distributions of 239+240Pu and 137Cs fallout in agricultural soil were investigated in Rokkasho where Japan's first commercial nuclear fuel reprocessing plant
is now being constructed. The mean inventories of 239+240Pu and 137Cs in three fields with non-yam-cultivation history were 116 Bq·m−2 and 3.4 kBq·m−2, respectively. The mean atomic ratio of 240Pu/239Pu for all studied fields was 0.18±0.04, and was similar to that of global fallout. The 239+240Pu concentrations correlated very well with 137Cs (r = 0.97) in spite of heavy disturbance of the soil, and the activity ratio of 239+240Pu/137Cs was 0.037±0.007, which is a typical value for global fallout. These results showed that the nuclides had similar behavior
in agricultural upland fields in Rokkasho. Since 210Pb is steadily deposited from the atmosphere to the land, this nuclide could be an index for the degree of disturbance of
a field and of soil lost from the field. The ratio of excess 210Pb inventory in the soil to the equivalent inventory of atmospheric 210Pb deposition was 96%, and indicated that soil was not lost from the cultivated fields.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Y. Narazaki K. Fujitaka S. Igarashi Y. Ishikawa N. Fujinami 《Journal of Radioanalytical and Nuclear Chemistry》2003,256(3):489-496
Seasonal variations of 7Be deposition in regions throughout Japan (26°18'N-43°05'N, 127°54'E-141°27'E) were observed during the period of 1989-1995. The observation indicated that 7Be deposition peaked in spring all over Japan except in the inland central basin. However, spring peak was not always the annual maximum. Along the coastal side of the Japan Sea, especially around Hokuriku region, 7Be deposition was at its maximum in winter. In addition, September peak also was observed in some regions, which was presumably caused by high precipitation or blowing in of northern air stream. Variations were classified into 4 types according to meteorological factors and local geographical conditions: winter peak, double peaks (spring and September peaks), spring peak and non-peak. A correlation between 7Be deposition and precipitation was observed in winter. 相似文献
11.
Inventories of 239+240Pu, 137Cs, and excess 210Pb in sediment cores from brackish Lake Obuchi, Rokkasho Village, Japan 总被引:1,自引:0,他引:1
The aim of this study was to measure the distribution and inventories of 239+240Pu, 137Cs, and excess 210Pb (210Pbexcess) in sediment core samples from brackish Lake Obuchi, which is in the vicinity of nuclear fuel facilities in Rokkasho Village, Japan. The inventory of the 239+240Pu activity in the sediment samples from the estuary of a freshwater river, the central point of the lake, and the deepest point in the lake were 0.18, 0.29, and 0.24 kBq·m–2, respectively. The inventories of 137Cs and 210Pbexcess in sediments were 0.83–1.2 kBq·m–2 and 25–30 kBq·m–2, respectively. The mean 239+240Pu/137Cs and 210Pbexcess/137Cs activity ratios were 0.23 and 28, respectively. The239+240Pu/137Cs activity ratios were approximately 13–24 times the ratio expected from global fallout. The inventories of 239+240Pu and 210Pb in sediments were higher than the inventory expected from atmospheric fallout, but the 137Cs inventory was significantly lower than expected.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
12.
Deposition of 226Ra from water on nylon was investigated. Measurements performed for different pH and different radium concentrations in the water gave similar absolute activities deposited on the foil surface. Obtained results were used to estimate the amount of 226Ra plated-out on the nylon scintillator vessel in the solar neutrino experiment BOREXINO during filling of the detector. Another problem studied in the frame of BOREXINO was the removal of 210Pb from its organic liquid scintillator by applying distillation and water extraction. After several tests had been performed for both methods it was found that after the water extraction the initial lead content in the scintillator sample was reduced only accordingly to the ratio of the volumes of the applied liquids (simple dilution). In contrast to this, distillation was very effective providing in the best case a 210Pb reduction factor higher than 100. Removal efficiencies of the long-lived 222Rn daughters during etching from surfaces of standard and high purity germanium were investigated in the frame of the GERDA experiment, which aims to search for neutrino-less double beta decay of 76Ge. The standard etching procedure of Canberra used during production of high purity n-type germanium diodes was applied to germanium discs, which had been exposed earlier to a strong 222Rn source for its progenies deposition. In contrast to copper and stainless steel, 210Pb, 210Bi and 210Po was removed from germanium very efficiently. An evidence of a reverse process was also observed—the isotopes were transferred from the etchant to the clean germanium surface. 相似文献
13.
C. Dueñas M. C. Fernández J. Carretero E. Liger S. Cañete 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):249-253
Measurements of 7Be and 210Pb in atmospheric air (1 m above the ground) have been carried out each week over one and a half year period. The method used to determine 7Be and 210Pb activities is based on the total amount of radioactive aerosols filtered from the air. The activities of 7Be and 210Pb were determined by a hyper-pure germanium detector using standard gamma-spectrometry. The average weekly concentrations of 7Be were in the range of 1.21-12.1 mBq.m-3 and for 210Pb in the range of 0.8-2.4 mBq.m-3. The weekly variations were discussed in relation to various meteorological factors. It can be said that our results showed a prevailing influence of weekly average temperature for 7Be concentration and the weight of aerosols and wind speed for 210Pb oncentrations. 相似文献
14.
N. Momoshima S. Nishio Y. Kusano A. Fukuda A. Ishimoto 《Journal of Radioanalytical and Nuclear Chemistry》2006,267(2):297-304
Summary A relatively simple chemical separation procedure has been developed for the simultaneous determination of89Sr and 9 0Sractivities in water samples and on aerosol-filters of the Nuclear Power Plant (NPP) Paks origin. The procedure combines
the cation-exchange chromatographic (Dowex 50 WX 8 resin) and solid phase extraction (EIChroM Sr.Spec?, DC18C6 crown ether)
steps. The beta-radiation of radionuclides can be measured directly after the chemical separation by LSC. The activities of89Sr,90Sr and90Y are calculated from an over determined set of equations using a method of constrained optimization technique. The equations
are based on LSC measurements performed in three counting windows plus the90Sr-90Y decay law. The chemical yield of strontium is determined by ICP-AES. The lowest limits of detectable activity, for the measurement
time of 600 minutes, are 30 mBq/sample and 18 mBq/sample for89Sr and90Sr, respectively. 相似文献
15.
Che Abd Rahim Mohamed Asnor Azrin Sabuti Nor Affizah Saili 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(2):257-263
Biogenic burning as forest fire phenomena occurring from April to August each year in the Sumatra and Borneo islands are major sources of biogenic uranium–thorium decay series in marine systems. 30 samples were collected during the Ekspedisi Pelayaran Saintifik Perdana 2009 cruise (EPSP 2009 cruise) between 12th June and 1st August 2009 from the Straits of Malacca to the Sulu and Sulawesi Seas to study the effect of haze and the monsoon season on the deposition rate of 210Po and 210Pb in Malaysian waters. All samples were spiked with 1 ml of lead [Pb(NO3)2; 25 mg ml?1] and 0.05 ml of Polonium-209 tracer (26.08 dpm ml?1). 210Po activity was determined by auto plating onto silver foil and counting using an alpha spectrometry system (Canberra model Alpha Analyst with a silicon-surface barrier detector). Lead that was collected via electrodeposition, formed lead sulphate (PbSO4) precipitation. This precipitate was wrapped onto plastic discs and counted for 210Pb beta activity using a gross alpha–beta counting system (Tennelec model LB-5100 low background gas-flowing anti-coincidence alpha/beta counter) after 1 month to allow bismuth ingrowths. The range of 210Po activities varied between 51.08 ± 15.1 and 742.08 ± 220.34 Bq/kg, whereas the activity of 210Pb ranged from 31.10 ± 4.20 to 880.23 ± 123.86 Bq/kg and 210Po/210Pb ratio value varied between sampling stations from 0.19 to 13.77. The contents of 210Po were also statistically positively correlated with the amount of total suspended particulate especially those recorded during heavy haze period events. 相似文献
16.
Yong Yi Peng Zhou Guangshan Liu 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):157-162
The atmospheric deposition fluxes of 7Be, 210Pb and 210Po at Xiamen were measured. The samples were collected from March 2004 to April 2005 and the sampling period was one month.
The 7Be and 210Pb activity were measured using HPGe γ-spectrometer after concentration using Fe(OH)3 co-precipitation method. The 210Po was counted with an α-spectrometer after the sample was digested and spontaneous plated onto a silver planchet. At Xiamen,
the atmospheric deposition fluxes of 7Be varied between 0.11 and 2.93 Bq·m−2·d−1 and the average was 1.64 Bq·m−2·d−1; 210Pb fluxes varied between 0.04 and 0.85 Bq·m−2·d−1, and the average was 0.51 Bq·m−2·d−1; 210Po fluxes varied between 0.002 and 0.133 Bq·m−2·d−1, and the average was 0.061 Bq·m−2·d−1. There were positive correlations between the deposition fluxes of 7Be, 210Pb or 210Po and the amount of precipitation. The residence time of aerosols varied between 6.0 and 54.0 days with a mean of 27.1 days,
which were calculated by 210Po/210Pb fluxes ratios. 相似文献
17.
H. Muramatsu S. Yoshizawa T. Abe T. Ishii M. Wada Y. Horiuchi R. Kanekatsu 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(2):299-307
The concentration of 7Be in surface air at Nagano City has been measured during the period from August 2000 to March 2005. The average monthly concentrations
of 7Be in surface air were in the range of 3.3–14 mBq/m3 with pronounced two peaks in spring and autumn. It took 30–40 hours to recover the 7Be concentrations observed before, once 7Be was washed out by wet precipitations. For a pronounced increase in the concentrations of 7Be found in winter, a low-pressure trough coming close to the Japanese Islands with high concentrations of 7Be is responsible under the characteristic distribution of atmospheric pressure around the Japanese Islands. 相似文献
18.
K. Irlweck 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(1):191-196
A new method for the radioanalytical determination of the 222Rn progenies 210Pb, 210Bi and 210Powill be presented, which has been improved for analyses of water samples fromdifferent regions in Austria. 1–2 liter samples were taken in polyethylenebottles prefilled with conc. HNO3 to obtain 0.2M acidic solutions,thus avoiding adsorption effects. After adding 1.6 mg of inactive lead carrier,the water sample was evaporated to dryness, converted to the chloride formand dissolved in 1M HCl. 相似文献
19.
Tee Lee Theng Zaharuddin Ahmad Che Abd. Rahim Mohamed 《Journal of Radioanalytical and Nuclear Chemistry》2003,256(1):115-120
Sediment cores were obtained from Teluk Brunei, Sipitang, Teluk Kimanis, Kota Kinabalu and Kuala Penyu at the coastal water of Sabah and analyzed for 210Pb and 210Po to estimate the sedimentation rates. The calculated sedimentation rates of 210Pb and 210Po varied from 0.003 to 0.049 cm/y and 0.74 to 8.77 cm/y, respectively. The highest sedimentation rates were determined for 210Pb and 210Po at stations located at Sipitang (mean: 0.027 cm/y) and Teluk Kimanis (mean: 5.53 cm/y), respectively. The sedimentation rate estimated for 210Pb is not fully reliable because the activity of 226Ra was higher than that of 210Pb and bioturbation was active at the sampling stations. 相似文献
20.
铀系核素210Po、210Bi和210Pb的测试在铀矿地质勘查与核废物安全处置研究、沉积年代学与同位素地球化学研究、大气环境学与辐射卫生学研究等诸多领域具有重要意义。重点总结了近些年来210Pb、210Bi和210Po三核素各种测试技术的研究进展与现状,评述了存在的主要问题及未来发展趋势。 相似文献