大直径单桩风机基础冰荷载模型试验研究

针对渤海某海域以单桩结构为支撑的海上风电系统,对大直径直立桩风机基础进行了一系列静冰载荷模型试验研究。首先,针对目标海域海冰调研结果确定多个冰速工况,对3 MW及4 MW装机功率对应的两种不同直径的单桩基础开展静冰载荷模型试验;随后在试验现象及试验结果的分析中重点关注了冰排在大直径结构前的破坏模式及破坏特点;最终,通过对比模型试验冰力极值试验结果与多规范冰载荷计算结果,确定大直径直立桩静冰载荷计算规范的合理选择,并根据试验结果对直立桩静冰载荷计算方法进行了经验参数修正。得出的相关结论可为渤海海域大直径单桩式风机基础冰载荷的工程估算提供参考。     

A comparative study of nonlinear Markov chain models for conditional simulation of multinomial classes from regular samples

Simulating fields of categorical geospatial variables from samples is crucial for many purposes, such as spatial uncertainty assessment of natural resources distributions. However, effectively simulating complex categorical variables (i.e., multinomial classes) is difficult because of their nonlinearity and complex interclass relationships. The existing pure Markov chain approach for simulating multinomial classes has an apparent deficiency—underestimation of small classes, which largely impacts the usefulness of the approach. The Markov chain random field (MCRF) theory recently proposed supports theoretically sound multi-dimensional Markov chain models. This paper conducts a comparative study between a MCRF model and the previous Markov chain model for simulating multinomial classes to demonstrate that the MCRF model effectively solves the small-class underestimation problem. Simulated results show that the MCRF model fairly produces all classes, generates simulated patterns imitative of the original, and effectively reproduces input transiograms in realizations. Occurrence probability maps are estimated to visualize the spatial uncertainty associated with each class and the optimal prediction map. It is concluded that the MCRF model provides a practically efficient estimator for simulating multinomial classes from grid samples.     

Distorted polyester lines for model testing of offshore moored platforms

Model tests of floating offshore platforms replace the mooring lines by inextensible cables connected to steel springs with a linear restoring capability. With the help of fundamental investigation on the similarity laws, the present work shows that the use of very thin polyester lines in model scaling is feasible and may allow a better physical representation of the full-scale polyester lines. The proposal is to use polyester lines with length distortion in order to keep the similar restoring capability and therefore, the same non-linear behavior would also be present during the tests. The work describes the application of these ideas in a model test of an Floating Production Storage and Offloading (FPSO) submitted to regular and random waves. The tests include both the linear spring lines and the distorted equivalent polyester lines, holding the FPSO model, submitted transversally to the same waves.     

国产尾标定位系统的研究及应用

对中国石油大学自主研发的全球卫星导航系统(GNSS)尾标定位系统的组成及运行原理进行了详细的阐述.介绍了该尾标定位系统在海洋拖缆作业中的应用,包括其核心软硬件的设计和主要工作流程.通过陆上模拟实验,对其电台传输距离和稳定性及定位精度进行测试,测试结果表明,尾标定位系统能够连续稳定地传输数据且能够实现厘米级的相对定位精度,可以满足实际生产中海上拖缆作业对导航定位的需求.     

利用终端位置时空转移概率预测通讯基站服务用户规模

基站服务用户数的预测对通信基站的空间位置选取、通讯服务带宽的配置优化等有重要作用,并为城市公共安全管理方面中的人群聚集预警与群体事件预防提供辅助决策支持。本文利用海量手机轨迹数据,运用时空转移概率定量化描述城市内不同区域间人群流动的时空特性,结合马尔可夫链和贝叶斯定理,构建手机用户群体在基站间的时空转移概率模型,并以此提出一种城市区域尺度上的基站服务用户数预测方法。利用湖北省某城市长达30 d的手机轨迹数据进行模型训练与预测方法验证,实验结果表明：在时间粒度为60 min时,本文提出的方法对8-22时各时段基站服务用户数预测准确率都大于94.8%;在不同时间粒度下对比本文方法、Castro模型、移动平均法,发现在时间粒度大于20 min时,本文方法预测准确率高于另外两种方法。     

Spatial and temporal variations in minibasin geometry and evolution in salt tectonic provinces: Lower Congo Basin,offshore Angola

In passive margin salt basins, the distinct kinematic domains of thin‐skinned extension, translation and contraction exert important controls on minibasin evolution. However, the relationship between various salt minibasin geometries and kinematic domain evolution is not clear. In this study, we use a semi‐regional 3D seismic reflection dataset from the Lower Congo Basin, offshore Angola, to investigate the evolution of a network of minibasins and intervening salt walls during thin‐skinned, gravity‐driven salt flow. Widespread thin‐skinned extension occurred during the Cenomanian to Coniacian, accommodated by numerous distributed normal faults that are typically 5–10 km long and spaced 1–4 km across strike within the supra‐salt cover. Subsequently, during the Santonian–Paleocene, multiple, 10–25 km long, 5–7 km wide depocentres progressively grew and linked along strike to form elongate minibasins separated by salt walls of comparable lengths. Simultaneous with the development of the minibasins, thin‐skinned contractional deformation occurred in the southwestern downslope part of the study area, forming folds and thrusts that are up to 20 km long and have a wavelength of 2–4 km. The elongate minibasins evolved into turtle structures during the Eocene to Oligocene. From the Miocene onwards, contraction of the supra‐salt cover caused squeezing and uplift of the salt walls, further confining the minibasin depocentres. We find kinematic domains of extension, translation and contraction control the minibasin initiation and subsequent evolution. However, we also observe variations in minibasin geometries associated with along‐strike growth and linkage of depocentres. Neighbouring minibasins may have different subsidence rates and maturity leading to marked variations in their geometry. Additionally, migration of the contractional domain upslope and multiple phases of thin‐skinned salt tectonics further complicates the spatial variations in minibasin geometry and evolution. This study suggests that minibasin growth is more variable and complex than existing domain‐controlled models would suggest.     

Assessing Collaborative Conservation: A Case Survey of Output,Outcome, and Impact Measures Used in the Empirical Literature

Abstract

Much existing research on collaborative conservation has focused on process, even as researchers have called for greater attention to explaining what results these processes yield. It is time to take stock of collaborative conservation research by mapping what kinds of variables researchers are including in analyses. Here we conduct a case survey from the SCAPE database of environmental decision-making cases. We include cases involving collaboration across government, environmental protection, and resource exploitation interests in western democratic countries. Results reveal patterns in what researchers include in their outputs, outcomes, and impacts measures of collaborative conservation. While there is little difference by publication type (peer-reviewed journals, scholarly book chapters, or gray literature) or over time, we find significant differences in explicit measures across variable types. In particular, variables more proximate to process in a logic chain are more often measured, as are social rather than ecological variables.     

产业集群生态产业链构建研究

由专业化集聚阶段向产业链集聚阶段推进是产业集群的重要发展趋势,按照生态产业链构建以循环经济为特征的产业集群具有重要意义。产业集群生态产业链构建包括产业集群产业和企业发展分析、核心行业(企业)的选定、生态产业链的系统集成、生态链(网)的设计及管理与设施建设等。产业集群生态产业链构建定量分析评价方法有代谢分析、资源分析和生命周期评价等。     

中国沿海地区构建城市带战略思考

文章分析了沿海地区形成城市带的机理和作用,构划了在沿海地区建设从北到南绵延几千公里。包括辽东半岛城市群、京津唐城市群、山东半岛城市群、长江三角洲城市群、福建沿海城市群、珠江三角洲城市群在内的巨型城市带的设想。城市带以香港、上海、京津为龙头,以厦门、青岛、大连为结点,以滨海山水城市为特色,以城市组合为手段,以观念和制度创新为理念,以加强城市间物流、人流、信息流、科技流为目标,整合优势资源,实施可持续发展,构筑开放、流动、有序、互补的城市带,形成城市带—城市群—城市圈3个层次城市带空间结构。最后,探讨了实施城市带建设的有关问题。     

长江中下游杨树抑螺防病林昆虫多样性的初步研究

对安庆市南埂林场长江沿岸杨树抑螺防病林3年生、8年生和20年生林地上空间昆虫群落的种群组成和多样性进行了调查。结果表明,在3种不同林龄林分之间,地上空间昆虫种群组成的差异表现为,在目一级分类单元组成上,3种不同林龄林分具有很高的共性,在科和种的单元上,不同林龄林分之间的差异大小依次为:3年生与20年生林分之间>3年生与8年生林分之间>8年生与20年生林分之间。随着林分林龄的增加,林内地上空间昆虫丰富度指数、Shannon-Wiener指数明显降低。不同林龄林分地上空间昆虫种群的均匀度指数与林分林龄无明显的相关性,其中20年生林分昆虫种群的均匀度指数显著低于8年生和3年生的林分,而8年生和3年生林分之间没有显著差异。