共查询到20条相似文献，搜索用时 953 毫秒
1.
讨论几种海藻糖的提取方法,着重对比热蒸馏水法和热碳酸钠法提取海藻糖的优缺点。实验结果表明碳酸钠溶液提取得到的海藻糖量较多,但是提取液中的碳酸钠给后续的提纯工作带来很大的麻烦。用蒸馏水提取海藻糖成本低,无毒性,不需要溶剂回收设备,后续的提纯工作简单,得到的晶体纯度高。 相似文献
2.
3.
4.
本文总结了国内外海上平台登临方式,并设计了一种新型海上无人平台登临装置。这一新装置具有结构简单、占用空间小、系统可靠等优点,本文详细描述了该装置的登临和离开工作流程及控制模式,并针对不同作业阶段设置了不同的控制模式,通过设计安全性仿真实验及实验参数,确保在6级风况下,装置臂展长度需大于1.42 m,以保障人员的安全。同时,本文探讨了该装置的关键技术,如人员姿态识别、船舶运动检测与预测等,这些技术的应用有望提高作业的安全性和效率。未来,新型海上无人平台登临装置的发展趋势将集中在人工智能技术的应用,以进一步提高作业人员的安全,并实现远程操控和设备维护。这一新型智能装备将具备识别、感知和实时监测功能,以应对不断变化的海上工作环境,同时注重信息反馈,以支持后勤维修工作。 相似文献
5.
脐带缆是深海油气开发的关键设备之一,主要由钢管单元、电缆单元、光缆单元、护套及铠装单元组成。脐带缆在全寿命周期经过设计制造、储存、安装、在位运行、修复阶段,其每个阶段的可靠性并不是某个常数,而是随时间变化的函数,因此有必要对脐带缆全寿命周期可靠性的变化进行分析。建立某气田水下脐带缆在储存、安装、在位运行阶段的故障树模型,将其转化为多阶段贝叶斯网络模型进行建模分析,基于OREDA手册数据,假设部件寿命服从指数分布,对脐带缆存储、安装、在位运行阶段的可靠性进行分析,得到不同阶段脐带缆可靠性的变化曲线,并与可靠性框图方法进行对比分析。同时,通过引入条件可靠性对该方法进行了优化,分析脐带缆修复后的可靠性变化,以及对脐带缆关键部件进行重要度分析,针对薄弱环节提出改进措施。可靠性分析可为水下脐带缆的安全运行提供技术支持,同时也为海洋结构与设备的全寿命周期可靠性分析提供了一种方法参考。 相似文献
6.
针对自主水下机器人的路径规划问题,提出一种基于双频识别侧扫声呐(DIDSON)的全局路径规划算法。根据双频识别侧扫声呐的物理特性对AUV进行数学建模,根据声呐的工作频率不同,将AUV分为高频、低频两种工作模式。高频模式下成像精度高,低频模式下成像范围大。文中提出了一种D2-CPP算法,根据声呐返回的识别结果,算法会自主切换AUV的工作模式,并动态规划出对应的路径点,直到覆盖所有区域。通过与割草机算法的仿真对比,证明了算法的有效性,近海实验证明了算法的可靠性。 相似文献
7.
针对无人潜航器(UUV)在未知水下复杂环境的路径规划问题，设计了随机树以及动态窗口的融合算法。该算法基于快速扩展随机树(RRT)以及动态窗口(DWA)两层规划设计，第一层利用随机树算法快速规划出全局路径，在此基础上第二层加载全局路径，针对 UUV 模型的欠驱动和非线性，利用动态窗口算法完成局部路径规划，保证约束条件下 UUV 路径的安全性。通过融合参数 μ 修正内外框架的融合度，有效地弥补了全局路径算法的无法躲避动态障碍物的缺点以及局部路径算法全局能力低下的问题。最后，通过对比仿真验证了融合算法相比于随机树全局算法和动态窗口局部算法的优越性。 相似文献
8.
9.
《中国海洋大学学报(自然科学版)》2017,(8)
基于结构构件承载能力分级原则,求解出既有结构与新建结构不同后续使用年限鉴定分级系数。首先,根据既有结构与新建结构抗力数理模型的不同,归纳整理出对应的抗力统计参数;其次,根据荷载标准值调整前后的不同,求解出设计基准期下对应的鉴定分级系数;再次,依据后续使用年限调整系数与统计参数的不同,计算出现行规范条件下不同后续使用年限对应的鉴定分级系数。最后,加入考虑抗力衰减因素,对比得出鉴定分级系数的安全富余程度,为将来实际鉴定工作提供参考和借鉴。 相似文献
10.
本文以中国埕岛油田某退役油区海底输油管道拆除工程为例,建立了海底管道拆除安全分级体系和模糊评价模型。通过现场调查和专家咨询,将管道拆除过程划分为4个阶段和11个工作步骤,并将各个步骤的安全性影响因素归纳为4个一级指标和15个二级指标。在此基础上,采用层次分析法计算各级评价指标的模糊评价权重,并依据加权平均原则分别对各级评价指标进行模糊综合评价。结果表明,在各一级指标的评价等级中,海底管道拆除的技术方案与设备选择和管道状况对拆除安全产生的影响最大,具有较高的危险隐患。该工程整体安全性级数为临界安全。 相似文献
11.
海岛资源的可持续发展研究是海洋开发与管理的重要课题。为优化配置海岛资源,促进海岛开发利用和生态环境保护的协调发展,文章对国内外海岛生态脆弱性研究的概念化过程、研究框架和评价方法进行综述,并在此基础上提出研究展望。研究结果表明:脆弱性的概念已由单一维度的自然系统或社会系统向2个维度的社会-生态交互系统拓展,海岛生态脆弱性的概念化过程具有同样的演进轨迹,但尚未清晰地揭示2个维度之间的多因素耦合关系;目前海岛生态脆弱性的研究框架多是已有脆弱性研究框架的延伸和拓展,尚未出现专门的研究框架;已有的生态脆弱性评价方法主要包括综合指数法、函数模型法、图层叠置法、情景分析法和系统动力学等,但缺乏适用于评价海岛生态脆弱性时空动态特征的方法;针对上述不足,未来海岛生态脆弱性研究应着重统一基本概念并构建专门的研究框架,在理清海岛生态脆弱性动态变化机制的基础上,完善评价指标体系和评价方法,并加强管理调控研究。 相似文献
12.
河口滨海湿地生态服务功能突出,生境脆弱易损,研究其生态脆弱性对滨海湿地生态环境保护与管理具有重要意义。本文以辽河口滨海湿地为例,基于“干扰-敏感-恢复”评估框架,选取17个指标,构建滨海湿地生态脆弱性评价指标体系,以GIS技术为支撑,综合运用插值法、综合指数法,探究辽河口滨海湿地生态脆弱性空间分布特征,分析生态脆弱性变化的影响因素。结果表明:入海河口污染、河口地区人类开发活动和自然淤涨对河口滨海湿地生态脆弱性的影响较为突出;2014年辽河口滨海湿地生态脆弱性总体态势良好,区域生态脆弱性指数为1.67,整体处于不脆弱状态;空间上,辽河口滨海湿地生态脆弱性表现为中部高于四周,由入海河口向外逐步减弱的格局特征。 相似文献
13.
为提高我国海洋环境监测技术水平,保障海洋环境信息安全,文章基于我国自主研发的北斗卫星导航系统,设计海洋环境监测系统。研究结果表明:基于北斗卫星导航系统的海洋环境监测系统包括北斗海洋环境监测终端和海洋信息综合服务平台2个部分,具有实时定位、实时监测、数据处理、信息预警、电子围栏、数据总览和用户管理7项功能;终端集成微控制单元和传感器等模块,平台包括服务器等硬件和数据处理等软件;经实地部署和严格测试,系统功能和性能均达到设计要求,且安全、稳定、方便和实用。 相似文献
14.
《Marine Policy》2013
Certification and eco-labeling schemes for the ecological sustainability of seafood have increased in recent years due, in large part, to consumer demand. While most attention has been focused on the population status and trends of target and bycatch species, the conservation of vulnerable species, communities, habitats and ecosystems (VSCHEs) has not consistently been addressed in an adequate manner, especially in data-poor systems. Unfortunately knowledge of VSCHE distribution patterns is inadequate, and even the leading fishery certification agencies only broadly address impacts to VSCHEs. Little guidance has been given to third party certifiers for gathering and evaluating appropriate information for assessing VSCHEs, and there is no explicitly precautionary method of assessing their vulnerability in an information poor environment. These shortcomings led to significant differences in how the impacts of fisheries on VSCHEs have been evaluated from one assessment to another, potentially resulting in a certified fishery when existing information suggests there are significant impacts. This study develops an explicit approach for data mining and evaluation for the eco-labeling certification process; proposes a precautionary method for assessing vulnerability of VSCHEs based on exposure, sensitivity and resilience and provides an example of how these can be integrated into existing fishery certification frameworks. This overall approach is also amenable for use by governmental agencies to advance conservation of VSCHEs within ecosystem-based management frameworks. 相似文献
15.
《Marine Policy》2016
As climate change continues to impact socio-ecological systems, tools that assist conservation managers to understand vulnerability and target adaptations are essential. Quantitative assessments of vulnerability are rare because available frameworks are complex and lack guidance for dealing with data limitations and integrating across scales and disciplines. This paper describes a semi-quantitative method for assessing vulnerability to climate change that integrates socio-ecological factors to address management objectives and support decision-making. The method applies a framework first adopted by the Intergovernmental Panel on Climate Change and uses a structured 10-step process. The scores for each framework element are normalized and multiplied to produce a vulnerability score and then the assessed components are ranked from high to low vulnerability. Sensitivity analyses determine which indicators most influence the analysis and the resultant decision-making process so data quality for these indicators can be reviewed to increase robustness. Prioritisation of components for conservation considers other economic, social and cultural values with vulnerability rankings to target actions that reduce vulnerability to climate change by decreasing exposure or sensitivity and/or increasing adaptive capacity. This framework provides practical decision-support and has been applied to marine ecosystems and fisheries, with two case applications provided as examples: (1) food security in Pacific Island nations under climate-driven fish declines, and (2) fisheries in the Gulf of Carpentaria, northern Australia. The step-wise process outlined here is broadly applicable and can be undertaken with minimal resources using existing data, thereby having great potential to inform adaptive natural resource management in diverse locations. 相似文献
16.
17.
In this paper, author employed Jacobi elliptic function expansion method to build the new wave solutions of time fractional modified Camassa–Holm equation which is completely integrable dispersive shallow-water equation. In ocean engineering, Camassa–Holm equation is generally used as a tool in computer simulation of the water waves in shallow sees, coastal and harbors. The obtained solutions show that the Jacobi elliptic function expansion method (JEFEM) which based on Jacobi elliptic functions is an efficient, reliable, applicable and accurate tool for analytic approximation of a wide variety of nonlinear conformable time fractional partial differential equations. 相似文献
18.
《Marine Policy》2017
Assessment of fisheries vulnerability to climate change is an important step for enhancing the understanding and decision-making to reduce such vulnerability. This study aimed to provide an analysis of country level vulnerability focusing on food security implications of climatic disturbances on marine fisheries. The comparative magnitude and distribution of potential food security impacts of climatic disturbances on marine fisheries were assessed for 109 countries by scoring and ranking countries against a set of vulnerability criteria including metrics of national exposure, sensitivity and adaptive capacity, highlighting the contribution of marine fisheries to national food and nutrition security. Results showed that developing countries in Africa, Asia, Oceania, and Latin America appeared to be most vulnerable, and the key sources of vulnerability differed considerably among the countries. For countries most vulnerable to climate-induced effects on marine fisheries, more than two-thirds of them depended on domestic marine fisheries as a main source of fish supply. Developing appropriate adaptation policies and management plans to reduce the impacts of changing climate is of great importance to sustain food security in these highly vulnerable and heavy marine fisheries-dependent countries. 相似文献
19.
20.
从海洋石油开发实际需求出发,通过分析海上油田安控系统的基本原理及其组成,详细介绍了如何利用M apX控件构建3G(GPS/GIS/GPRS)综合信息处理平台,根据系统流程对海图制作、船舶定位、航行轨迹记录和安控与调度等关键部分进行设计与实现。该系统为海上油田作业及航运提供远程监控、调度和安全控制,确保海上油田施工作业安全,提高航运效率。 相似文献