This paper proposes that on the basis of near-source saturation characteristic of ground motion, the peak ground motion acceleration and the acceleration response spectra of diffuse earthquakes affecting the nuclear f...This paper proposes that on the basis of near-source saturation characteristic of ground motion, the peak ground motion acceleration and the acceleration response spectra of diffuse earthquakes affecting the nuclear facility site can be determined by the statistic method. In view of the problem of insufficient statistic samples due to fewer qualified strong earth- quake records on the bedrock site, it also proposes that according to the features of ground motion response of the soil, the acceleration records on the soil site can be transformed into the equivalent acceleration records on rock site for a simultane- ous statistic analysis together with the records on rock site. Consequently, we have obtained by this method the near-source peak acceleration and the acceleration response spectra of small and moderate earthquakes on the site that could meet the need of nuclear facility and made a comparative analysis to the results from relevant researches. This new method for deter- mining diffuse earthquakes is only preliminarily verified in the paper and further research is needed for practical application.展开更多
In recent years, there has been growing concern about the impact of diffuse source pollution on water bodies, particularly due to associated health risks. Coastal waters can receive considerable inputs of pollutants f...In recent years, there has been growing concern about the impact of diffuse source pollution on water bodies, particularly due to associated health risks. Coastal waters can receive considerable inputs of pollutants from catchments since they serve as sinks for many diffuse pollutants. Furthermore, bathing waters have in the recent past often failed to comply with the various standards set by different bathing water directives. The Severn estuary has recently attracted a lot of attention in terms of bathing water compliance due to its potential to generate a considerable amount of renewable energy for the UK. It is against this background that a physical model of the estuary has been set up in the Hydraulics Laboratory at Cardiff University, for studies to be undertaken to mimic the conditions of the prototype. A sandbox filled with non-cohesive sediments within the laboratory has been set up to investigate the behaviour of pollutants in propagating from the idealised groundwater environment into the estuarine waters. It has been demonstrated that for a semi-diurnal tidal estuary like the Severn, tides have a lesser effect on the transport of solutes than flows from the catchments. Thus the impact of pollution from diffuse sources to marine environments from catchments could be higher in less tidally dominated coastal waters than a tidal one.展开更多
近红外漫射光相关断层成像技术(Diffuse Correlation Tomography,DCT)是一种乳腺微血管血流成像的新技术,但成像的空间分辨率不足,高密度光源探测器(Source and Detector,S-D)阵列的布置方式是否可以有效提高DCT空间分辨率目前尚不清楚...近红外漫射光相关断层成像技术(Diffuse Correlation Tomography,DCT)是一种乳腺微血管血流成像的新技术,但成像的空间分辨率不足,高密度光源探测器(Source and Detector,S-D)阵列的布置方式是否可以有效提高DCT空间分辨率目前尚不清楚。为了研究S-D阵列密度对于DCT血流重建图像空间分辨率的影响,设计了3种S-D阵列,密度分别为24、48和96。结合蒙特卡洛仿真和DCT血流图像重建方法,研究了S-D阵列对于2种含有高血流异质物(模拟乳腺恶性肿瘤)的乳腺组织血流重建效果的影响。结果表明,高密度的SD阵列交错排布可以提高DCT血流重建的空间分辨率,可提升临床早期筛查时乳腺恶性肿瘤成像的精确性和稳定性。展开更多
基金supported by the Special Funds for Sciences and Technology Research (No. 200708003 and No. 200808008)National Natural Science Foundation of China (No. 90715020)
文摘This paper proposes that on the basis of near-source saturation characteristic of ground motion, the peak ground motion acceleration and the acceleration response spectra of diffuse earthquakes affecting the nuclear facility site can be determined by the statistic method. In view of the problem of insufficient statistic samples due to fewer qualified strong earth- quake records on the bedrock site, it also proposes that according to the features of ground motion response of the soil, the acceleration records on the soil site can be transformed into the equivalent acceleration records on rock site for a simultane- ous statistic analysis together with the records on rock site. Consequently, we have obtained by this method the near-source peak acceleration and the acceleration response spectra of small and moderate earthquakes on the site that could meet the need of nuclear facility and made a comparative analysis to the results from relevant researches. This new method for deter- mining diffuse earthquakes is only preliminarily verified in the paper and further research is needed for practical application.
文摘In recent years, there has been growing concern about the impact of diffuse source pollution on water bodies, particularly due to associated health risks. Coastal waters can receive considerable inputs of pollutants from catchments since they serve as sinks for many diffuse pollutants. Furthermore, bathing waters have in the recent past often failed to comply with the various standards set by different bathing water directives. The Severn estuary has recently attracted a lot of attention in terms of bathing water compliance due to its potential to generate a considerable amount of renewable energy for the UK. It is against this background that a physical model of the estuary has been set up in the Hydraulics Laboratory at Cardiff University, for studies to be undertaken to mimic the conditions of the prototype. A sandbox filled with non-cohesive sediments within the laboratory has been set up to investigate the behaviour of pollutants in propagating from the idealised groundwater environment into the estuarine waters. It has been demonstrated that for a semi-diurnal tidal estuary like the Severn, tides have a lesser effect on the transport of solutes than flows from the catchments. Thus the impact of pollution from diffuse sources to marine environments from catchments could be higher in less tidally dominated coastal waters than a tidal one.
文摘近红外漫射光相关断层成像技术(Diffuse Correlation Tomography,DCT)是一种乳腺微血管血流成像的新技术,但成像的空间分辨率不足,高密度光源探测器(Source and Detector,S-D)阵列的布置方式是否可以有效提高DCT空间分辨率目前尚不清楚。为了研究S-D阵列密度对于DCT血流重建图像空间分辨率的影响,设计了3种S-D阵列,密度分别为24、48和96。结合蒙特卡洛仿真和DCT血流图像重建方法,研究了S-D阵列对于2种含有高血流异质物(模拟乳腺恶性肿瘤)的乳腺组织血流重建效果的影响。结果表明,高密度的SD阵列交错排布可以提高DCT血流重建的空间分辨率,可提升临床早期筛查时乳腺恶性肿瘤成像的精确性和稳定性。
