海洋浮游植物粒径等级遥感研究现状与展望

海洋水体中浮游植物粒径等级的差异能反映其功能类型的不同,浮游植物粒径等级的探测对水生态系统中浮游植物功能多样性及浮游植物生物地理化学功能的研究具有极其重要的意义。本文综述当前浮游植物粒径等级的遥感探测算法,阐述各算法的步骤过程及其特点,并分析了优缺点。基于此,针对我国近海及海岸带水体,提出海洋浮游植物粒径等级(phytoplankton size classes,PSCs)遥感研究今后需要开展的工作。     

建筑围护结构风荷载的计算与取值

风荷载为建筑中受力结构和围护结构的主要可变荷载,现行建筑结构荷载规范分别列出了受力结构和围护结构风荷载wk的计算公式,但依据不同规范计算所得结果差别较大.这里通过采用不同规范,对风荷载值进行计算分析比较,提出建筑设计中wk计算公式的选用及相关建议,供设计人员参考.     

鄱阳湖沙山高分辨率沙质地层及其冬季风气候信息记录的初步探究

位于鄱阳湖流域的长江、赣江等河谷、河漫滩的下风方向,由于处于冬季风强烈的东亚季风区,在高频率出现的大风、强风天气情况下,受风力吹蚀作用,常形成区域性的沙山堆积.沙山纵向垄状地形发育,其上风方向,槽、沟与碟形坑等侵蚀地貌发育,其下风方向,纵向沙垄发育.通过对样品的光释光年代测试和粒度频数分析,浅析星子PBL剖面的小冰期风积地层,揭示了小冰期晚期持续近60年左右的一次冷期,这个冷期以突变开始,以渐变结束,其清晰程度在其它地质记录中是不曾发现的.研究发现鄱阳湖沙山纵向沙垄往往具有缓倾斜的前积与侧积,层理(薄层与细层)往往较稳定,对揭露冬季风气候信息具有重要的意义.     

Functional metagenomic profiling of nine biomes

Microbial activities shape the biogeochemistry of the planet and macroorganism health. Determining the metabolic processes performed by microbes is important both for understanding and for manipulating ecosystems (for example, disruption of key processes that lead to disease, conservation of environmental services, and so on). Describing microbial function is hampered by the inability to culture most microbes and by high levels of genomic plasticity. Metagenomic approaches analyse microbial communities to determine the metabolic processes that are important for growth and survival in any given environment. Here we conduct a metagenomic comparison of almost 15 million sequences from 45 distinct microbiomes and, for the first time, 42 distinct viromes and show that there are strongly discriminatory metabolic profiles across environments. Most of the functional diversity was maintained in all of the communities, but the relative occurrence of metabolisms varied, and the differences between metagenomes predicted the biogeochemical conditions of each environment. The magnitude of the microbial metabolic capabilities encoded by the viromes was extensive, suggesting that they serve as a repository for storing and sharing genes among their microbial hosts and influence global evolutionary and metabolic processes.     

Charge structures and cloud-to-ground lightning discharges characteristics in two supercell thunderstorms

The characteristics of CG lightning discharges have been studied because they often result in the disaster and are easier to be observed than intracloud discharge. In early stage, the locations of charges in cloud are de- termined based on the multi-stati…     

两阶段目标类指引的行人检测对抗补丁生成算法

针对缘于深度学习模型脆弱性的对抗样本攻击这一国内外热门研究课题，以无人驾驶等实际应用为背景，探讨了针对Yolo-v2行人检测系统的对抗攻击方法;基于Yolo-v2对行人目标的预测置信度和分类概率，提出基于两阶段目标类指引的行人检测对抗补丁生成算法。创新性地提出了目标类指引的攻击策略，通过先后实施目标类指引的对抗补丁生成和对抗补丁增强，有效引导了对抗补丁在训练生成过程中的收敛方向，以此逐步提升对抗补丁攻击行人检测系统的能力;在Inria数据集上实现了79个目标类指引的对抗补丁生成训练与测试。结果表明，算法以“teddy bear”为目标类生成了攻击效果最佳的对抗补丁，行人检测交并比(IOU)指标可达0.043 5，显著优于对照算法的0.244 8。