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排序方式: 共有463条查询结果,搜索用时 203 毫秒
1.
Hitoshi Kawabata Hisashi Narita Koh Harada Shizuo Tsunogai Masashi Kusakabe 《Journal of Oceanography》2003,59(5):651-661
Thirteen vertical profiles of 226Ra and 222Rn in the near-surface water were obtained in the western North Pacific in winter, and the gas transfer velocities across
the air-sea interface were estimated. The transfer velocities found by applying a steady state model varied widely from 2.1
to 30.2 m day−1 with a mean of 9.4 m day−1. The mean value is almost 5 times higher than that in summer in other oceans, and the maximum value is a record high for
world oceans. This is partly due to the inadequacy of the steady state model, which overestimates when stronger winds blow
in more recent days than the 222Rn half-life of about 4 days. In fact, a strong low pressure zone passed through the station about 2 days earlier, which was
one of the low pressure zones that with a period of develop once a week or so in the northwestern North Pacific in winter.
Instead of steady-state removal, if half of the radon removal occurred sporadically every 7 days, and the last removal took
place two days before the observation, the transfer velocity would be 26 m day−1. Our mean transfer velocity, which is less than 20% different from the steady state value including both overestimated and
underestimated values, 9.4 ± 4.8 m day−1, seems to represent the mean state of this region in winter. This suggests that the gas exchange fluxes under extremely rough
conditions in the open ocean are larger than those estimated by using a transfer velocity equation with a linear or quadratic
relationship with wind speed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
B.P. Chernyago A.I. Nepomnyashchikh G.I. Kalinovskii 《Russian Geology and Geophysics》2008,49(12):971-977
Relations between indoor and soil gas radon were experimentally studied in villages of the Baikal region. On the basis of the obtained data, the soil-to-indoor radon ratio was calculated, which can be used for prediction of radon pollution in buildings of the same kind. 相似文献
3.
F. Bella R. Bella P. F. Biagi M. Caputo G. Della Monica A. Ermini E. Pettinelli V. Sgrigna 《Pure and Applied Geophysics》1993,141(1):125-137
Prototype instrumentation, able to automatically measure groundwater radon content variations, is presented. The equipment is made of stainless steel and has spherical valves with automatic and pneumatic control. The deemanation of the gases from the water is obtained by evacuating a suitable expansion chamber. The instrumentation can make discrete sampling ranging from 1 per hour to 1 per 99 hours. The equipment was tested in the laboratory: the efficiency was measured by means of a266Ra solution. A mean value of (0.65±0.07) count/s/Bq was obtained. A calibration test was carried out by comparing countings from the automatic equipment with those obtained by the standard laboratory cell. Results of an operational check over a period of approximately one year indicate that variations in radon at the calibration site are attributable more to meteorological than to tectonic causes. 相似文献
4.
1983年菏泽5.9级地震前后沂水泉氡的变化 总被引:1,自引:0,他引:1
沂水泉位于山东省沂水一汤头断裂带上。多年来的观测分析表明,影响沂水泉氡值变化的最大干扰是降雨。由于这种干扰存在着“记忆”滞后影响,所以用一般的相关分析难以将这种影响排除干净。本文对最小二乘法为建立模型的判据,用动态灰箱分析法拟合并推估观测系统的变化。在分析中用了四个状态变量:长趋势成分L(t)、年周期变化成分P(t)、降雨影响部分R(t)和随机变化部分S(t)。经过分析表明,沂水泉氡的长趋势部分1 相似文献
5.
相对湿度对静电收集型连续测氡仪检定结果的影响 总被引:1,自引:0,他引:1
NR-667A(Ⅲ)型快速连续测氧仪是目前环境氡测量时间响应最短的一种仪器。该仪器在核工业第六研究所标准氡室进行检定时发现,环境相对相对度对仪器检定结果有很大影响。在相对湿度为80%-99%的标准氡室内分别对仪器进行检定,结果在相对湿度为80%时仪器检定合格,而在相对湿度为99%时仪器检定不合格。本从仪器工作原理对检定结果进行。并提出有效的解决方法,当相对湿度太大时,可在仪器进气口安装干燥器对进气进行除湿。 相似文献
6.
2001年云南澜沧5.0、施甸5.2,5.9,5.3、宁蒗5.8、楚雄5.3和江川5.1级地震前,云南49项水氡前兆中的一些台站出现突出的异常。研究发现,根据这些异常项的异常特征和空间分布特征及历史震例,可对这几次地震预报的三要素,尤其是地点和时间做出较好的判断。 相似文献
7.
8.
在进行地下流体数字化气氡观测及将观测资料应用于震情分析的过程中 ,发现某些干扰因素对数字化气氡观测和水氡的影响不同。在目前所用观测仪器和方法的条件下 ,气温对气氡值的影响系数为 - 0 4 % /℃ ;气压对气氡测值的影响系数为 0 1% /hPa ;不同类型的气水分离装置对气氡观测的影响很显著 ;同一含水层的井 (泉 )出水量的短期变化可引起观测水井流量的变化 ,但对气氡测值影响不显著 ;气氡测值对逸出气流量的变化反映不明显 ;逸出气含有杂质及气路泄漏等均会引起测值的下降。结合仪器的工作原理 ,对干扰产生的机制以及排除的方法进行了讨论 相似文献
9.
10.