深空背景下空间目标红外特性建模方法研究

针对空间目标红外特性提出了一种精确建模方法.根据空间目标的背景辐射环境,充分考虑到目标表面间的热传导及内热源的影响,建立了空间目标的热平衡方程.基于目标的结构特性和材料特性,利用节点网络法求解了目标表面的温度分布.根据光辐射定律、光散射定律建立了空间目标红外特性的数学模型.结合具体的参数,对深空目标资源一号卫星和风云三号卫星的温度场分布和辐照度分布进行了数值计算,仿真结果验证了理论分析的正确性.     

捕食者不同目标策略下的鱼群结构变化仿真与研究

在海洋生态环境中,食物链上层捕食者对下层鱼群的捕猎行为可以被普遍地观察到,捕食者攻击的策略以及鱼群的防御机制是海洋捕猎行为的关键。本文构建了鱼群行为模型并对捕食者目标选择策略进行模拟,3种策略分别是选择“最近”“最中心”和“最外围”的个体。在虚拟环境中模拟单个捕食者攻击鱼群这一过程,对3种目标选择策略做比较分析,以鱼群结构变化程度的3个关键参数做评判标准。首先发现采用选择“最外围”个体的策略对于中等规模鱼群造成的结构变化程度最大,其次拓展到不同大小规模的鱼群,此策略仍是最有效的,其中小规模鱼群因应对风险能力低,无法体现三种策略的区别。     

基于深度学习的光学遥感影像舰船检测算法对比分析

舰船目标检测是进行海洋环境监管,保障海上权益的重要手段。基于深度学习的目标检测算法能在复杂环境下保持良好性能,为测试不同深度学习目标检测算法在舰船检测中的效果,本文构建了一个包含3893张图像的数据集,涵盖了复杂背景下不同类型的舰船,基于此数据集分别采用Faster RCNN、SSD、RetinaNet、YOLOv3、YOLOv4算法进行实验,结果表明,YOLOv4 、YOLOv3、RetinaNet、Faster RCNN平均精度均在83%以上,其中YOLOv4最高达到91.77%,Faster RCNN误检较多,而SSD平均精度最低,只有79.23%,总的舰船检测数目偏少。将5种模型训练结果在高分二号影像上进行测试,得到较好的检测效果,对舰船检测未来理论研究的开展具有一定的指导意义。     

1.5℃温升目标下中国碳排放路径研究

《巴黎协定》提出1.5℃目标以及中国2060年前达到碳中和的目标背景下,为研究实现1.5℃目标的技术路径,构建了综合性的能源-经济-环境系统模型,研究中国在2℃情景基础上实现1.5℃目标的额外减排要求、部门贡献和关键减排措施.结果显示,1.5℃情景要求到2050年CO2排放量减少到6亿t.一次能源消费总量2045年达峰...     

面向遥感目标识别耦合GA与SVM的特征优选方法

提出了GA-SVM耦合用于高分遥感目标识别的特征优选方法,将GA中的特征降维和适应度函数构建与SVM中的特征空间映射、样本训练以及分类结果在内容上耦合,利用SVM的识别结果指导GA的进化方向。同时,为减小未成熟收敛风险,对传统GA做了改进。实验表明,该方法在高分遥感影像目标识别中效果较好。     

清水塘铅锌矿床的成因及其找矿方向

清水塘铅锌矿床位于关帝庙岩体西南侧,赋存于寒武系上统及(?)陶系白水溪组中,有与地层整合的整合型似层状矿体和切层的脉带型矿体。矿石中除Pb、Zn、Cu、Fe外,尚有Ag、In、Sb、Ga、Ge等20多种元素。层位控制矿床的分布,岩性及断裂控制矿体产出。成矿元素组合,矿石包体特征及均一法测温结果和硫同位素组成等显示矿床属构造一热卤水再造成因。     

The characteristics,formation and exploration progress of the potash deposits on the Khorat Plateau,Thailand and Laos,Southeast Asia

The giant potash deposit on the Khorat Plateau is one of the most promising targets for exploitation of potassium salts. So far, many researches and geologic survey have been conducted on the giant potash deposits. Hence, it is necessary to make an overall review on the potash deposits. The potash deposit on the Khorat Plateau was formed during the Middle to Late Cretaceous, during which seawater was enriched in Ca²⁺ and depleted in SO₄^2- compared with those of modem seawater. In addition to seawater, continental water and hydrothermal fluids could have affected the evaporite basins. The seawater was probably derived from Tethys ocean, and the brine should have evaporated to some extent before entering into the basin systems based on the evidence of absence of carbonates and unproportionate sulphate compared with chloride salts. The paleo-climate during Middle to Late Cretaceous was characterized as high temperature and extremely arid environment, which is favourable for deposition of potassium-magnesium saline minerals. The major saline minerals are of anhydrite, halite, camallite, sylvite and, tachyhydrite, with trace amounts of borates. The resources of the potash deposit on the Khorat Plateau could be approximately as much as 400×10⁹ t of camallite and 7×10⁹ t of sylvite. The evaporite sequences have been deformed and altered by postdepositinal processes, including tectonic movements and chemical alteration. Salt domes were formed in the postdepositional processes. Based on the analyses of geophysical surveys and drilling projects, high-quality sylvinite ores are commonly found at the flanks of those salt domes due to incongruent dissolution of camallite. The future potential prospecting areas for the high-quality sylvinite ores would be on the edges of the Khorat Plateau.     

中国地质学会2019年度“十大地质科技进展”和“十大地质找矿成果”评选揭晓

中国地质学会于2020年3月召开了2019年度“十大地质科技进展”和“十大地质找矿成果”终评会议,评选产生了2019年度“十大地质科技进展、十大地质找矿成果”获奖项目。获奖项目是经各推荐单位推荐,学会形式审查、公示、初评、终评等环节产生的。     

水库渔业营养类型划分标准研究──1.指标层次的确定

依据１９８０－１９９２年全国２０个省５５座水库渔业资源调查数据,运用Ｒ型聚类分析和主成分分析方法对４８项指标间的层次性进行分析,水库渔业营养类型划分标准的指导层次体系可确定为：第一层次包括地理,气候,水深,面积和体积,土壤,水文等６个小层次;     

A basic study on the application of LRFD in “the technical standard for port and harbour facilities in Japan”: a case of gravity type quay wall in a persistent design situation

ABSTRACT

The Partial Factor Method (PFM) based on the Level 1 reliability design method was introduced in 2007 to the Technical Standards for Port and Harbour Facilities (TSPHF-2007) in Japan. After nearly 10 years of practical use of TSPHF-2007, the design standard has been revised based on requests from the practitioners who recommend the transition from the PFM to the Load Resistance Factor Design (LRFD). In this paper, we discuss the setting method of the target failure probability to determine the partial factors based on code calibration. Furthermore, we examine the impacts of implementing the LRFD concept to the TSPHF by taking the sliding and overturning of a gravity type quay wall as an example to represent port and harbour facilities. We found no practical difference in caisson width derived using the LRFD and the PFM, whereas the degree of matching of the target failure probability was somewhat more precise for the PFM. This finding indicates that the LRFD is a more reasonable design method than the PFM in terms of the simplicity of the performance function itself and the ease of engineering interpretation during the design procedure.