湖南乡村生活质量的空间格局及其影响因素

认知乡村生活质量的地域分异规律及形成原因,既是新时代乡村地理学研究的新内容,也是科学实施“乡村振兴”战略的内在要求。以湖南省101个县（市、区）为研究单元,构建由6个维度组成的乡村生活质量评价指标体系,运用熵权法、探索性空间数据分析（ESDA）及地理探测器等研究方法,研究湖南乡村生活质量的空间格局特征及其影响因素。结果表明：湖南乡村生活质量总体上呈现出东高西低并由东向西依次递减的空间分布态势;从空间关联格局来看,HH区和LL区在空间上集聚格局明显,显著HH区主要分布在长株潭城市群地区和周边临近县域,显著LL区主要分布在大湘西地区;影响湖南乡村生活质量空间格局的重要因素为人均GDP、城镇化水平、离省会城市距离、海拔,次重要因素为坡度、第二第三产业占比、农村非农劳动力占比、农业机械总动力。振兴乡村,提高乡村生活质量应在充分保护乡村生态环境的基础上,把乡村产业振兴和经济振兴放在优先的位置,应积极改善广大乡村地区的互联互通条件,促进乡村地区基础设施和公共服务设施的现代化。     

Re-identifying Grateloupia yangjiangensis (Rhodophyta, Halymeniaceae) based on morphological observations, life history and rbcL sequence analyses

On the basis of morphological observations, life history and molecular phylogeny, Grateloupia yangjiangensis, which is similar to G. filicina, G. orientalis, G. catenata, and G. ramosissima in appearance, was re-examined. The results are as follows:(1) the auxiliary-cell ampullae of G. yangjiangensis were of Grateloupia type, thalli was fleshy and gelatinous in texture, and the erect axes were compressed; the cortex was 0.25–0.30 mm thick, consisting of five to seven outer layers, and there were five inner layers of triangular or stellate cells;(2) there was no filamentous stage in the development of the carpospores;(3) the ribulose-1,5-bisphosphate carboxylase/oxygenase gene(rbcL) sequence of four G. yangjiangensis examined showed that there was no intergeneric divergence among them, and for the phylogenetic tree, four sequences of G. yangjiangensis formed a single monophyletic subclade within the large Grateloupia clade of Halymeniaceae. In conclusion, G. yangjiangensis was a single species within the genus Grateloupia. This research provided criterion for identification and cultivation of G. yangjiangensis.     

海蜇生活史的补充研究

为了更详细地阐述海蜇(Rhopilema esculentum)生活史,作者应用显微观察和对比分析方法,对其各阶段的生长特征进行了研究,继而对已报道的海蜇生活史进行了资料补充。研究结果表明:根据浮浪幼虫纵轴长度及活力将其分为早期、中期和晚期浮浪幼虫;在海蜇浮浪幼虫变态附着和足囊萌发过程中,补充了杯状体发育阶段;根据伞部中胶层变化、中央口发育状况及棒状附着器的出现与否,对碟状体至幼蜇的发育阶段进行了重新划分,将海蜇浮游幼体划分为碟状体、稚蜇和幼蜇3个阶段。实验结果完善了海蜇早期生活史,为深入开展海蜇基础生物学和基础生态学研究提供参考。     

深水SCR触地区管-土相互作用试验研究进展

与海床的相互作用是钢悬链线立管特有的性质,是传统立管发展中不曾遇到的问题,也是控制立管疲劳寿命的主要因素,特别是触地区出现的峰值弯曲应力和管土接触模型的不确定,成为SCR触地区研究的难点。由于立管与海床的作用机理非常复杂,因此管土相互作用模型的提出大多是建立在模型试验的基础上。通过对国内外深水SCR触地区管土相互作用试验研究案例的分析,简要介绍了SCR触地点的动态响应取决于一系列参数,如海床土刚度、加载状况、立管的提升速度、土的重塑时间和土吸力等,并设计了一套三维管-土相互作用的试验装置,能够为深水钢悬链线立管触地区管-土相互作用的试验研究提供参考。     

混凝土结构全寿命设计指标体系研究

考虑混凝土结构全寿命设计的多目标要求,提出结构全寿命设计指标由核心指标和绿色指标两个层次构成。将结构的性能指标、经济指标、时间指标作为全寿命设计的核心指标;将CO2排放量指标、用户满意度指标和可持续发展能力指标作为结构设计的绿色指标。提出混凝土结构全寿命设计需以结构的性能设计为中心,并将结构的性能指标分为风险性能指标、技术性能指标、材料性能指标三类。针对结构性能退化的特点,建议了有害介质扩散深度、钢筋锈蚀率、锈胀裂缝宽度作为耐久性的设计指标,同时定义了退化率指标γt用以反映结构性能退化的程度。在此基础上建立了结构全寿命设计的指标体系,为结构设计人员进行全寿命优化设计提供了理论依据。     

Deep-water riser fatigue monitoring systems based on acoustic telemetry

Marine risers play a key role in the deep and ultra-deep water oil and gas production. The vortex-induced vibration (VIV) of marine risers constitutes an important problem in deep water oil exploration and production. VIV will result in high rates of structural failure of marine riser due to fatigue damage accumulation and diminishes the riser fatigue life. In-service monitoring or full scale testing is essential to improve our understanding of VIV response and enhance our ability to predict fatigue damage. One marine riser fatigue acoustic telemetry scheme is proposed and an engineering prototype machine has been developed to monitor deep and ultra-deep water risers’ fatigue and failure that can diminish the riser fatigue life and lead to economic losses and eco-catastrophe. Many breakthroughs and innovation have been achieved in the process of developing an engineering prototype machine. Sea trials were done on the 6th generation deep-water drilling platform HYSY-981 in the South China Sea. The inclination monitoring results show that the marine riser fatigue acoustic telemetry scheme is feasible and reliable and the engineering prototype machine meets the design criterion and can match the requirements of deep and ultra-deep water riser fatigue monitoring. The rich experience and field data gained in the sea trial which provide much technical support for optimization in the engineering prototype machine in the future.     

Significant effects of fishing gear selectivity on fish life history

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual’s traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectiv-ity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. Ac-cording to the existing tend of exploited fish individual’s life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.     

Historical demography of southern African patellid limpets: congruence of population expansions,but not phylogeography

Global climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum. Such expansions and the ability of species to colonise new habitats will influence their genetic structure, but the link between scales of larval dispersal and the strength of phylogeographic structure is not always clear. We analysed a fragment of the mitochondrial COI gene of 11 sympatric species of intertidal southern African patellid limpets to investigate how ancient oceanographic dynamics have shaped and maintained their contemporary spatial genetic variation. Our data show that the patellid limpets investigated display congruent evidence of spatial expansion during the Late Pleistocene or Early Holocene, which corresponds with the establishment of the contemporary southern African shoreline. We argue that closely related and co-distributed southern African intertidal invertebrates responded to ancient climatic oscillations as a cohesive group. In contrast, contemporary oceanographic circulation has shaped the phylogeographic patterns of these limpets in different ways. We show close relationships between phylogeography and biogeography for some species, but not for others, despite the similarities in their life histories and exposure to the same climatic changes.     

老龄半潜式钻井平台节点疲劳裂纹扩展寿命预报

通过结合常规谱疲劳分析方法和裂纹扩展分析方法,给出了一种工程实用的评价老龄平台节点裂纹扩展寿命的方法,并以某一平台为例进行了验证计算。首先,基于谱疲劳分析得到各个节点在过去30年的节点疲劳损伤,然后,对损伤接近或大于1.0的节点进行基于单一曲线模型的裂纹扩展分析,以求得该节点在目前状态下裂纹扩展寿命。结果表明,目标平台计算疲劳热点满足继续使用的要求。此外,针对不同初始裂纹尺寸时的裂纹扩展寿命计算结果表明初始裂纹尺寸对疲劳裂纹扩展寿命影响很大。     

Generation and Application of A Standardized Load-Time History to Tubular T-joints in Offshore Platforms

Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation (FCP) theory rather than the currently used cumulative fatigue damage (CFD) theory. A unified fatigue life prediction (UFLP) method for marine structures has been proposed by the authors’ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history (SLH) such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.