The geometric and spatial characteristics of pore structures determine the permeability and water retention of soils, which have important effects on soil functional diversity and ecological restoration. Until recentl...The geometric and spatial characteristics of pore structures determine the permeability and water retention of soils, which have important effects on soil functional diversity and ecological restoration. Until recently, there have not been tools and methods to visually and quantitatively describe the characteristics of soil pores. To solve this problem, this research reconstructs the geometry and spatial distribution of soil pores by the marching cubes method, texture mapping method and the ray casting method widely used in literature. The objectives were to explore an optimal method for three-dimensional visualization of soil pore structure by comparing the robustness of the three methods on soil CT images with single pore structure and porosity ranging from low (2–5%) to high (12–18%), and to evaluate the reconstruction performance of the three methods with different geometric features. The results demonstrate that there are aliases (jagged edges) and deficiency at the boundaries of the model reconstructed by the marching cubes method and pore volumes are smaller than the ground truth, whereas the results of the texture mapping method lack the details of pore structures. For all the soil images, the ray casting method is preferable since it better preserves the pore characteristics of the ground truth. Furthermore, the ray casting method produced the best soil pore model with higher rendering speed and lower memory consumption. Therefore, the ray casting method provides a more advanced method for visualization of pore structures and provides an optional technique for the study of the transport of moisture and the exchange of air in soil.展开更多
本文以2003—2023年Web of Science核心数据库中1098篇论文为样本,采用文献计量学和可视化方法,分析科技伦理国际研究热点和演进趋势。结果发现:整体上科技伦理国际研究呈持续上升趋势,大致经历4个发展阶段。科技伦理国际研究主要研究...本文以2003—2023年Web of Science核心数据库中1098篇论文为样本,采用文献计量学和可视化方法,分析科技伦理国际研究热点和演进趋势。结果发现:整体上科技伦理国际研究呈持续上升趋势,大致经历4个发展阶段。科技伦理国际研究主要研究力量分布在美国和英国,中国位列前十,虽排名比较靠后,但影响力在不断攀升。近20年的研究热点聚焦以下主题:①科技伦理的基础理论研究;②传统医疗卫生与健康政策的伦理研究;③新兴科技伦理风险识别及治理研究。展开更多
基金supported by the National Natural Science Foundation Project(41501283)Beijing Science and Technology Plan Project(Z161100000916012)+2 种基金the National Key Research and Development Program(2017YFD0600901)Special Fund for Beijing Common Construction Projectthe Fundamental Research Funds for the Central Universities(2015ZCQ-GX-04)
文摘The geometric and spatial characteristics of pore structures determine the permeability and water retention of soils, which have important effects on soil functional diversity and ecological restoration. Until recently, there have not been tools and methods to visually and quantitatively describe the characteristics of soil pores. To solve this problem, this research reconstructs the geometry and spatial distribution of soil pores by the marching cubes method, texture mapping method and the ray casting method widely used in literature. The objectives were to explore an optimal method for three-dimensional visualization of soil pore structure by comparing the robustness of the three methods on soil CT images with single pore structure and porosity ranging from low (2–5%) to high (12–18%), and to evaluate the reconstruction performance of the three methods with different geometric features. The results demonstrate that there are aliases (jagged edges) and deficiency at the boundaries of the model reconstructed by the marching cubes method and pore volumes are smaller than the ground truth, whereas the results of the texture mapping method lack the details of pore structures. For all the soil images, the ray casting method is preferable since it better preserves the pore characteristics of the ground truth. Furthermore, the ray casting method produced the best soil pore model with higher rendering speed and lower memory consumption. Therefore, the ray casting method provides a more advanced method for visualization of pore structures and provides an optional technique for the study of the transport of moisture and the exchange of air in soil.
文摘本文以2003—2023年Web of Science核心数据库中1098篇论文为样本,采用文献计量学和可视化方法,分析科技伦理国际研究热点和演进趋势。结果发现:整体上科技伦理国际研究呈持续上升趋势,大致经历4个发展阶段。科技伦理国际研究主要研究力量分布在美国和英国,中国位列前十,虽排名比较靠后,但影响力在不断攀升。近20年的研究热点聚焦以下主题:①科技伦理的基础理论研究;②传统医疗卫生与健康政策的伦理研究;③新兴科技伦理风险识别及治理研究。
