Video cathodoluminescence microscopy of diagenetic cements and its applications

Diagenetic studies of sedimentary rocks using cold cathodoluminescence (CL) microscopy have been severely limited because of the very low intensity of visible luminescent emissions, which required long photographic exposure times, and because of the difficulty in obtaining quantitative data from CL observations. The solution to this problem is to fit the microscope with a high-sensitivity digital colour video camera linked to a computer with image enhancement and image analysis software. The new technique described in this paper:

• produces digital CL images of consistent high quality, both quickly and cheaply;

• controls the capture and editing of CL images, to reveal detailed textural information even from minerals exhibiting low level luminescence such as quartz;

• acquires quantitative information on pore systems and the abundance of cement zones from CL images.

Examples are presented to demonstrate the high quality of images produced in this way and the range of uses to which the new technique can be applied. The ability to image exactly the same field of view in both plane polarised light and CL is a particular advantage. Image analysis techniques have been developed to give a statistical characterisation of both pore systems and cement phases that infill them. The abundance of contrasting cement zones seen in CL can be measured and the abundance of cement phases can be mapped across a reservoir. The history of porosity occlusion can be reconstructed quantitatively and integrated with burial history and hydrocarbon migration. Porosity can be measured accurately and, since the technique obtains data on pore geometry as well as abundance, the pore system can be characterised by pore size distributions and pseudo-capillary pressure curves. This also opens the possibility of estimating permeability from thin sections.     

1998年夏季南海水团分析

根据 1 998年夏季“南海季风试验 ( SCSMEX)”期间所获的 CTD资料 ,使用系统聚类、Fuzzy模式聚类、Bayes判别分析和 Fuzzy分析等水团分析方法 ,对南海水体的结构和水团配置状况等进行了分析 ,划出了南海存在的 9个主要水团 ,并对各水团的温、盐度特征进行了初析。在调查期间 ,南海本地水 (南海水 )几乎控制了整个调查海区 ,而黑潮水仅出现在台湾岛的西南海域 ;海水强烈混合发生在吕宋海峡附近 ;在中南半岛以东和吕宋岛以西海域 ,表层水明显下沉 ;在南海东南部可能有来自苏禄海的海水 ,其温、盐度特征类似于吕宋海峡中的黑潮水     

烟台市区河流入海口微生物群落的分析

2015年4月在烟台市区4条主要河流(辛安河、逛荡河、鱼鸟河和夹河)入海口处采集12个样品,利用PCR-DGGE方法分析了此区域的细菌群落组成和优势菌群。通过统计学手段对DGGE图谱进行分析,结果表明4条河流入海口细菌群落丰富度都较高,12个取样点扩增的DGGE条带数都在30以上,样品的Shannon指数均高于3.3,个别甚至可达3.61。其中,辛安河和逛荡河的Shannon指数平均值均高于鱼鸟河和夹河,夹河多样性最低;而且UPGMA聚类分析结果显示地理位置越接近,其细菌组成的相似度越高。在DGGE电泳条带中选取14条主要条带进行扩增和序列测定,所得到的序列进行了系统进化分析发现4条河流入海口的优势菌群主要为变形杆菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)。这与近年来关于山东近岸海域细菌多样性的研究结果相符合,为研究和保护烟台市区河口处环境提供科学依据。     

系缆损伤对绷紧式系泊系统动力响应的影响

探究合成纤维系缆损伤对绷紧式系泊系统响应的影响,具有重要的工程意义。通过高强聚乙烯(HMPE)缆绳损伤动刚度实验,获得其动刚度随损伤的演变规律。在数值计算上,借鉴并合理简化了前人提出的动刚度经验公式,通过处理实验结果确定动刚度经验公式的参数并进行验证。在此基础上,以一座采用高强聚乙烯缆绳为主体系缆的FPSO为例,将所得动刚度经验公式导入系泊分析软件,结合水动力分析,计算得到在相同海洋环境中,系缆发生不同程度损伤时,各系缆张力和平台偏移响应的结果。通过处理、分析所得的计算结果,获得合成纤维缆绳损伤演变对绷紧式系泊系统响应的影响规律,并据此为系缆更换提供了建议。这些成果既有利于把握绷紧式系泊系统的非线性动力响应,也对安全、经济、合理地运用合成纤维系缆具有重要意义。     

FPSO软刚臂单点系泊系统定量风险分析

针对FPSO软刚臂单点系泊系统出现过的系泊腿失效及背向工况风险事件,以渤海某16万吨级FPSO为例,采用数值模拟的方法,计算FPSO及单点系统在百年一遇海况下的载荷效应,通过统计学方法拟合效应的概率分布,完成定量风险分析。对于系泊腿旋转失效后的风险,使用故障假设(what-if)方法,依据失效后果判断其风险权重。计算结果表明,系泊腿结构在正常情况下受拉失效的概率很小;系泊腿纵摆失效后导致的结果比横摆失效更为严重,风险权重更大。背向工况下,船艏与YOKE的间距要明显小于顺向工况,在设计时增大二者间距可有效减小碰撞风险。     

固定式海洋平台结构风险设计方法综述

海洋平台的结构设计中主要考虑海洋环境和工作荷载作用,但近年来事故荷载的影响日益引起设计者关注。在此背景下,以固定式导管架平台结构为目标,综述当前针对事故荷载的风险设计方法的应用现状。首先论述在事故极限状态设计中应用风险分析的必要性;随后综述通用规范,如NORSOK、DNV、API等规范系列中对风险分析方法的使用现状,包括风险决策的不同层次、安全标准的各类形式,重在分析各类规范相关规定的异同,探讨各类方法的适用性;最后结合我国现状,论述若针对事故荷载编制基于风险方法的设计规范,目前尚存的问题,以及解决途径。     

Stability Analysis of Hybrid-Driven Underwater Glider

Hybrid-driven underwater glider is a new type of unmanned underwater vehicle, which combines the advantages of autonomous underwater vehicles and traditional underwater gliders. The autonomous underwater vehicles have good maneuverability and can travel with a high speed, while the traditional underwater gliders are highlighted by low power consumption, long voyage, long endurance and good stealth characteristics. The hybrid-driven underwater gliders can realize variable motion profiles by their own buoyancy-driven and propeller propulsion systems. Stability of the mechanical system determines the performance of the system. In this paper, the Petrel-Ⅱ hybrid-driven underwater glider developed by Tianjin University is selected as the research object and the stability of hybrid-driven underwater glider unitedly controlled by buoyancy and propeller has been targeted and evidenced. The dimensionless equations of the hybrid-driven underwater glider are obtained when the propeller is working. Then, the steady speed and steady glide path angle under steady-state motion have also been achieved. The steady-state operating conditions can be calculated when the hybrid-driven underwater glider reaches the desired steady-state motion. And the steady-state operating conditions are relatively conservative at the lower bound of the velocity range compared with the range of the velocity derived from the method of the composite Lyapunov function. By calculating the hydrodynamic coefficients of the Petrel-Ⅱ hybrid-driven underwater glider, the simulation analysis has been conducted. In addition, the results of the field trials conducted in the South China Sea and the Danjiangkou Reservoir of China have been presented to illustrate the validity of the analysis and simulation, and to show the feasibility of the method of the composite Lyapunov function which verifies the stability of the Petrel-Ⅱ hybrid-driven underwater glider.     

声学应答释放器电路部分可靠性分析

声学应答释放器是一种对可靠性要求很高的海洋环境监测设备,文中对国家海洋技术中心研制的声学应答释放器进行了可靠性分析。首先介绍了声学应答释放器的电路构成及功能;然后依据可靠性建模相关理论完成电路部分可靠性模型建立,依据可靠性模型,预计了设备的固有可靠度;最后有针对性地提出改进措施,用于指导声学应答释放器设计,为释放器技术研究提供计算模型与可借鉴的经验。