一种基于多特征波段岩土层次分类方法

岩土分类与一般地表的地物分类相比难度大得多,针对已有的分类方法（监督分类和非监督分类）对于岩土分类精度不高、分类效果欠佳问题提出一种基于多特征波段岩土层次分类方法。它是一种自顶向下、逐步求精的层次分类方法,该方法结合无监督分类和监督分类两种分类方法的优势,利用多个特征波段组合,有层次地将不同类型的岩土体逐步分开,实现对岩土的精确分类。对北京市怀柔山区附近的ASTER影像数据进行的岩土分类实验结果表明,基于多特征波段岩土层次分类识别方法能显著提高岩土分类精度,总体精度提高10%,Kappa系数提高了0.1,并且能识别以往分类识别方法难以区分的岩石阴影和水体等地物,能够有效地克服“同物异谱”现象。     

Prehistoric agriculture development in the Yunnan-Guizhou Plateau,southwest China: Archaeobotanical evidence

The origin, development and expansion of prehistoric agriculture in East Asia have been widely investigated over the past two decades using archaeobotanical analysis from excavated Neolithic and Bronze Age sites. Research on prehistoric agriculture has predominantly focused in the valleys of the Yellow River and the Yangtze River. Agricultural development during the Neolithic and Bronze Age periods in the Yunnan-Guizhou Plateau of southwest China, an important passageway for human migration into Southeast Asia, still remains unclear. In this paper, based on macrofossil and microfossil analysis and radiocarbon dating at the Shilinggang site, we investigate plant subsistence strategies in the Nujiang River valley during the Bronze Age period. Combined with previous archaeobotanical studies in the Yunnan-Guizhou Plateau, we explore agricultural development processes in this area during the Neolithic and Bronze Age. Our results indicate that rice and foxtail millet were cultivated in Shilinggang around 2500 cal a BP. Three phases of prehistoric agricultural development in the Yunnan-Guizhou Plateau can be identified: rice cultivation from 4800–3900 cal a BP, mixed rice and millet crop(foxtail millet and broomcorn millet) cultivation from 3900–3400 cal a BP, and mixed rice, millet crop and wheat cultivation from 3400–2300 cal a BP. The development of agriculture in the Yunnan-Guizhou Plateau during the Neolithic and Bronze Age periods was primarily promoted by prehistoric agriculture expansion across Eurasia, agricultural expansion which was also affected by the topographic and hydrological characteristics of the area.     

格陵兰冰盖表面消融研究进展

冰盖表面消融是格陵兰冰盖物质平衡的重要组成部分, 已成为近年来格陵兰冰盖研究的热点. 格陵兰冰盖表面消融研究的关键在于理解冰盖融水的产生、 运移和释放等水文过程, 需要解决如下关键科学问题: 1) 冰盖表面产生了多少融水;2)冰盖表面水文系统具有什么特征; 3)冰盖表面融水如何影响冰盖运动; 围绕这些科学问题, 总结了格陵兰冰盖表面消融的研究进展. 冰盖表面消融建模、 冰盖表面湖的信息提取与面积特征变化、 深度反演与体积量算等是目前研究冰盖表面融水量的主要途径, 冰盖表面湖、 冰盖表面径流、 锅穴与冰裂隙等表面水文要素的空间分布规律研究则可用于揭示冰盖表面水文系统特征, 冰盖表面融水与冰盖运动速率的关系、 表面融水进入冰盖内部与底部的水文过程是目前揭示表面融水如何影响冰盖运动的主要手段.     

光纤位移传感器在盐岩地下储气库群模型试验中的应用

为了研究盐岩地下储气库群运行过程中注采气压变化对洞周围岩变形的影响,设计开发了一种基于光纤布拉格光栅技术的棒式光纤位移传感器,并将其成功应用在盐岩地下储气库群模型试验的位移监测中。试验结果表明,注采气压速率是影响盐岩储气库运营安全的重要因素。采气过程中洞周出现径向收敛位移,该位移随采气速率和时间的增加而增加;注气过程中洞周出现扩张位移,该位移随注气速率和时间的增加而增加。空间上,气压变化对洞腔腰部位移影响最大。为了保证储气库运行安全,应控制注采气速率。针对所研究工程原型,建议储气库的最大采气速率应小于0.65 MPa/d,最大注气速率应小于0.75 MPa/d。     

表面活性剂强化含水层修复过程的全局灵敏度

针对非水相流体污染含水层的表面活性剂强化修复过程,在多相流数值模拟模型以及径向基函数人工神经网络替代模型的基础上,应用Sobol法对影响修复效果的变量进行全局灵敏度分析。当替代模型的训练集包含12组和22组数据时,替代模型与模拟模型拟合的确定性系数分别为0.977 8和0.981 6,表明随着训练集数据的增多,替代模型与模拟模型的近似精度逐渐增加。灵敏度分析结果表明：对修复效果贡献最大的决策变量为总抽水量(总灵敏度为0.491 2),其次为修复时间(总灵敏度为0.468 5),表面活性剂浓度对修复效果的贡献最小(总灵敏度为0.124 2);各个变量之间存在着相互作用,但相互作用对输出响应的影响不大。     

两种土层地震一维反应程序的对比分析

利用美国加州大学的土层地震反应分析程序EERA和中国地震局的RSLEIBM程序,以不同峰值下的典型地震波(EIcentro波)作为输入地震动,分别进行各自程序下的地震动计算,两个软件计算结果基本相同。     

Development and application of a novel miniature in situ microprofiler (NAFRI BelpI)

We have developed a novel miniature in situ microprofiler (NAFRI BelpI) for coastal and deep-sea studies. The BelpI can carry up to three oxygen microsensors, and it allows for simultaneous replicate measurements in a relatively small area. All functions can be controlled and programmed via a small magnetic bar and three reed switches; this feature facilitates the initial setup both onboard and underwater. The large LCD window shows basic information such as the movement intervals of the linear stage, number of replicate measurements, waiting time between measurements, and the pA from the microsensors. From high-resolution vertical profiles of oxygen in coastal sediment measured using the microsensors, the diffusivity boundary layer thicknesses was determined to be in the range 0.30–0.35 mm. In addition, the time-series measurement of oxygen profiles in permeable sandy sediment showed advective transport of oxygen into pore water by tidal agitation. Two examples of in situ measurement using a BelpI suggest that it can be widely applied to the study of the sediment-water interface.     

Tidal dynamics in the strong tidal current environment of the Uldolmok waterway, southwestern tip off the Korean peninsula

Uldolmok waterway, located between an island off the southwestern tip of Korean peninsula and mainland, is famous for its strong tidal current that has a maximum current of about 6.0m/s. A series of field observations along with numerical modeling have been carried out in order to understand the tidal dynamics in terms of the force balance along the whole waterway and the energy balance in the narrowest part of the waterway. First, analysis of the ADCP current and the tide level variation data reveals that the tidal dynamics along the total waterway (channel) is balanced dominantly between the pressure gradient and linear bottom frictional forces, with the phase lag of sea level difference for the semi-diurnal constituents leading the current phase about by 10°. Secondly, the result of the numerical modeling reveals that the tidal energy flux vector flows toward the narrowest section, indicating that there should be related nonlinear processes. Through the numerical model experiment with multi-components, the convergence of (M₂ + S₂) tidal energy flux of 6.68 × 10⁷ Joule/s in the narrow area of the Uldolmok waterway is explained mainly by the energy consumption of 73% through the nonlinear generation of shallow water components and by the bottom frictional energy dissipation of 27%. This reveals that the remarkably strong nonlinear process dominates in the narrowest section of the Uldolmok waterway, compared with other areas, such as Yellow and East China Seas where the total M2 energy flux through the open boundary is balanced in terms of the bottom dissipation (Kang et al. 2003; Choi 1980).     

Assessment of immune parameters of manila clam <Emphasis Type="Italic">Ruditapes philippinarum</Emphasis> in different physiological conditions using flow cytometry

Cellular and humoral immune parameters are often used as biomarkers to trace environmental and physiological stresses in marine bivalves. In this study, we compared various immune parameters of Manila clams (Ruditapes philippinarum) under normal conditions and under a high level of desiccation, using flow cytometry. The immune parameters analyzed included, total hemocyte count, hemocyte mortality, hemocyte DNA damage, reactive oxygen species (ROS) production, and phagocytosis activity. Total hemocyte count, hemocyte DNA damage, and hemocyte mortality were significantly elevated among clams under high desiccation stress, while phagocytosis activity and spontaneous ROS production were significantly lower compared to those parameters of the control clams (p<0.05). These data suggest that the immune parameters analyzed in this study well reflect the physiological status of clams.