Wave breaking on turbulent energy budget in the ocean surface mixed layer

As an important physical process at the air-sea interface, wave movement and breaking have a significant effect on the ocean surface mixed layer （OSML）. When breaking waves occur at the ocean surface, turbulent kinetic energy （TKE） is input downwards, and a sublayer is formed near the surface and turbulence vertical mixing is intensively enhanced. A one-dimensional ocean model including the Mellor-Yamada level 2.5 turbulence closure equations was employed in our research on variations in turbulent energy budget within OSML. The influence of wave breaking could be introduced into the model by modifying an existing surface boundary condition of the TKE equation and specifying its input. The vertical diffusion and dissipation of TKE were effectively enhanced in the sublayer when wave breaking was considered. Turbulent energy dissipated in the sublayer was about 92.0% of the total depth-integrated dissipated TKE, which is twice higher than that of non-wave breaking. The shear production of TKE decreased by 3.5% because the mean flow fields tended to be uniform due to wave-enhanced turbulent mixing. As a result, a new local equilibrium between diffusion and dissipation of TKE was reached in the wave-enhanced layer. Below the sublayer, the local equilibrium between shear production and dissipation of TKE agreed with the conclusion drawn from the classical law-of-the-wall （Craig and Banner, 1994）.     

无人化时代反水雷装备体系构想

根据我国海洋方向面临的战略安全环境、建设“海上丝绸之路”的要求,我国的反水雷作战范围将延伸到第一岛链以外的海域,反水雷任务除了传统的近岸/ 近海反水雷任务,还增加了海峡反水雷、交通线反水雷以及海外基地反水雷等任务。 为了满足我国反水雷作战需求,结合国际上反水雷技术装备发展方向,用信息化改造、无人化拓展现有反水雷装备,构建无人化时代反水雷装备体系,形成能够在近岸、近海、中远海实施快速、安全、高效的反水雷作战能力。     

水中目标信息智能识别方法研究

提出了基于判定准则的海洋环境下目标关系识别方法。通过HBACA算法查找或识别不同元素关系能力强的特性,提取目标信息数据的关系,之后在信息数据关系中计算每个信息节点的点度中心度、紧致中心度和节点活跃度,根据信息数据在目标事件中的重要或关键程度,将信息数据划分为关键目标信息、重要目标信息和一般目标信息。仿真结果显示:能够明确地获得关键的信息数据坐标,并与其所处事件的重要程度能够匹配,同时相关信息数据的关系非常明显,很容易提炼出所处目标事件中重要目标信息数据之间的关联。     

南海神狐海域沉积物自生黄铁矿和石膏S同位素特征及对甲烷渗漏强度的示踪

The northern slope of the South China Sea is a gas-hydrate-bearing region related to a high deposition rate of organic-rich sediments co-occurring with intense methanogenesis in subseafloor environments.Anaerobic oxidation of methane(AOM) coupled with bacterial sulfate reduction results in the precipitation of solid phase minerals in seepage sediment,including pyrite and gypsum.Abundant aggregates of pyrites and gypsums are observed between the depth of 667 and 850 cm below the seafloor(cmbsf) in the entire core sediment of HS328 from the northern South China Sea.Most pyrites are tubes consisting of framboidal cores and outer crusts.Gypsum aggregates occur as rosettes and spheroids consisting of plates.Some of them grow over pyrite,indicating that gypsum precipitation postdates pyrite formation.The sulfur isotopic values(δ~(34) S) of pyrite vary greatly(from –46.6‰ to –12.3‰ V-CDT) and increase with depth.Thus,the pyrite in the shallow sediments resulted from organoclastic sulfate reduction(OSR) and is influenced by AOM with depth.The relative high abundance and δ~(34) S values of pyrite in sediments at depths from 580 to 810 cmbsf indicate that this interval is the location of a paleo-sulfate methane transition zone(SMTZ).The sulfur isotopic composition of gypsum(from–25‰ to –20.7‰) is much lower than that of the seawater sulfate,indicating the existence of a 34 S-depletion source of sulfur species that most likely are products of the oxidation of pyrites formed in OSR.Pyrite oxidation is controlled by ambient electron acceptors such as MnO_2,iron(Ⅲ) and oxygen driven by the SMTZ location shift to great depths.The δ~(34) S values of gypsum at greater depth are lower than those of the associated pyrite,revealing downward diffusion of 34 S-depleted sulfate from the mixture of oxidation of pyrite derived by OSR and the seawater sulfate.These sulfates also lead to an increase of calcium ions from the dissolution of calcium carbonate mineral,which will be favor to the formation of gypsum.Overall,the mineralogy and sulfur isotopic composition of the pyrite and gypsum suggest variable redox conditions caused by reduced seepage intensities,and the pyrite and gypsum can be a recorder of the intensity evolution of methane seepage.     

粘性土微结构形态要素及其定量信息处理技术

本文论述了粘性土微结构的形态要素及其层次关系，提出了11种结构参数并难予了相应的图像定义；以分形理论为基础确定了7项非线性结构要素的定量描述方法及其分维指标，并对其定量信息获取手段——粘性土微结构图象处理系统（MIPS）作了简要介绍。     

Duffing振子系统周期解的唯一性与精确周期信号的获取方法

研究Duffing振子系统的周期解的唯一性与精确周期信号的获取方法. 应用定性分析方法,获得了一类Duffing振子系统具有唯一周期解的必要条件,同时也得到了一类更广泛的非线性周期系统的周期解的唯一性.在一定条件下,给出了Duffing振子系统精确周期信号的获取方法.     

上海市居民乡村旅游行为特征及感知研究

运用旅游心理学原理,采用比较分析和交互分析等研究方法,分析了上海市居民乡村旅游的人口学特征、行为偏好以及效果感知,并提出加强乡村旅游宣传力度、观念创新和服务管理等建议.     

中国大陆西部强震前超低频磁场时空变化特征

对2015年至2019年期间中国大陆西部的磁通门磁力仪秒采样观测资料开展了5—100 s频段的地磁垂直强度极化分析,并运用一些数学方法对分析结果进行了处理.结果显示,极化高值在经向和纬向均无明显的形态和幅值变化,且极化高值与地磁外源场扰动无关.在此基础上筛选出18次极化高值异常事件,利用插值方法得到了极化高值异常的空间...     

云南鹤庆—丽江地区锰资源量预测：资源量模型法的应用

云南鹤庆—丽江地区是我国著名的优质富锰矿产区,已探明储量超过300×10~4t。然而该区的锰资源量前景如何?本文试图运用资源量模型法,将鹤庆矿区作为已知模型区,通过模型区与预测区的特征分析,求出类比系数。最后通过随机抽样模拟,得出各种概率下预测区锰资源量估计值。