排序方式： 共有14条查询结果，搜索用时 31 毫秒
11.
Several procedures for non-linear static and dynamic analysis of structures have been developed in recent years. This paper
discusses those procedures that have been implemented into the latest European and US seismic provisions: non-linear dynamic
time-history analysis; N2 non-linear static method (Eurocode 8); non-linear static procedure NSP (FEMA 356) and improved capacity
spectrum method CSM (FEMA 440). The presented methods differ in respect to accuracy, simplicity, transparency and clarity
of theoretical background. Non-linear static procedures were developed with the aim of overcoming the insufficiency and limitations
of linear methods, whilst at the same time maintaining a relatively simple application. All procedures incorporate performance-based
concepts paying more attention to damage control. Application of the presented procedures is illustrated by means of an example
of an eight-storey reinforced concrete frame building. The results obtained by non-linear dynamic time-history analysis and
non-linear static procedures are compared. It is concluded that these non-linear static procedures are sustainable for application.
Additionally, this paper discusses a recommendation in the Eurocode 8/1 that the capacity curve should be determined by pushover
analysis for values of the control displacement ranging between zero and 150% of the target displacement. Maximum top displacement
of the analyzed structure obtained by using dynamic method with real time-history records corresponds to 145% of the target
displacement obtained using the non-linear static N2 procedure. 相似文献
12.
Morphometric variation was used to study population structure of the cutlassfish Trichiurus lepturus on the Kenyan coast. In all, 16 morphometric measurements taken from 193 individuals from six sites were subjected to multivariate statistical analysis in order to determine possible stock differentiation. Multivariate analysis of variance indicated significant differences in the means of a combination of the morphometric characters among the sites, and discriminant function analysis by groups showed the presence of phenotypically distinct populations on the south and north coasts of Kenya. A classification tree analysis of morphometric characters validated the distinct groups and indicated certain characters to be useful for classifying specimens to source sites. The likely presence of distinct north and south stocks of T. lepturus on the Kenyan coast observed in our study will require validation by other methods, but indicates the potential need for spatially explicit models for managing fish populations on a large spatial scale. 相似文献
13.
RW Jabado SM Al Ghais W Hamza DP Robinson AC Henderson 《African Journal of Marine Science》2016,38(2):217-232
Landing site and market surveys of sharks landed along the Arabian Gulf coast of the United Arab Emirates were undertaken between October 2010 and September 2012 to obtain biological data from this artisanal fishery. Data were collected on the size and sex of 12 482 individuals representing 30 species. Maximum sizes of Carcharhinus sorrah, C. amblyrhynchoides and Hemipristis elongata were extended by at least 300?mm total length (TL) compared with published global maxima. The size at 50% maturity was determined for males of five species and this indicated that the males of smaller shark species (<1 000 mm maximum TL) in the fishery were largely mature. For many species, including Loxodon macrorhinus and Mustelus mosis, overall sex ratios were male-biased, indicating that sexual segregation is likely in those species. Furthermore, sex ratios for several species, such as Rhizoprionodon acutus, showed differences across seasons. Overall, the landings contained a high proportion of juveniles, causing concerns about the sustainability of this fishery. Biological parameters of a number of species differed from those recorded earlier for the region, demonstrating a need for additional local data collection to support the development of management measures. 相似文献
14.
徐家围子断陷构造地质特征研究新进展 总被引：14，自引：1，他引：13
在徐家围子断陷深层连片三维地震精细解释的基础上,结合前人的研究成果,系统的刻画了深大断裂的性质、产状和时空分布规律。从区域构造应力场着手,详细剖析了徐家围子断陷的构造地质特征,重新构建了深大断裂体系。依据剖面特征和断陷的地质结构,首次在徐家围子断陷内解释出两条深大走滑断裂带,发现深大走滑断裂控制了营城组火山岩的形成和分布。明确了徐家围子断陷"两凹夹一隆、东西分带、南北分块"构造格局的动态演化过程及其控制因素。详细剖析了断陷期地层的沉积发育过程、后期改造过程以及现今赋存特征。为庆深气田火山岩储层分布规律预测奠定了基础。 相似文献