钢筋混凝土柱极限变形角的概率特性及其在有控结构大震可靠度分析中的应用

通过对国外大量试验数据的整理和分析，统计给出了钢筋混凝土柱极限变形角的概率特性；在假设结构层间极限变形角近似等于柱子极限菜角的基础上，结合文献[1]的研究结果，初步建立了被动耗能减振结构大震可靠度的分析方法。     

Younger Dryas Glaciation in Söderåsen, South Sweden: An Analysis of Meteorologic and Topographic Controls

In Söderåsen, South Sweden, various geomorphological investigations indicate that small, local glaciers were initiated at very low altitudes within the Skäralid rock canyon during the Younger Dryas period. Wind polish on boulders indicates that this period was characterised by easterly winds and drifting snow. Some new field observations are presented and the Söderåsen Younger Dryas reglaciation hypothesis is tested by means of empirical knowledge on glacier equilibrium line climate and an analytic geographical information system (GIS) experiment. The GIS analysis demonstrates that the deeply incised rock canyon represents a pronounced radiation shelter, while the empirical analysis emphasises the importance of strong snow drift from the east during the winter. Together, the two analyses indicate that the inferred Söderåsen Younger Dryas reglaciation is possible from a palaeoclimatic point of view, although conditions for glaciation may have been marginal to those of rock glacier initiation.     

A new investigation on drift of base-line value in geomagnetic observation

Ａｎｅｗｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｄｒｉｆｔｏｆｂａｓｅ┐ｌｉｎｅｖａｌｕｅｉｎｇｅｏｍａｇｎｅｔｉｃｏｂｓｅｒｖａｔｉｏｎＤＯＮＧ－ＭＥＩＹＡＮＧ（杨冬梅）ＹＵ－ＦＥＮＧＡＯ（高玉芬）ＹＯＮＧ－ＦＥＮＺＨＡＯ（赵永芬）ＷＥＩ－ＢＥＩＨＵＡＮＧ...     

北大西洋Hatton与Gardar沉积堤上等深线流活动的沉积学标志

 北大西洋东北部 Hatton 与 Gardar 沉积堤的早更新统沉积层分属两类不同的深海碳酸盐软泥。前者粗组份含量高,以有孔虫为主;后者明显变细,主要由超微化石组成。生物产率、水深、沉积速率及等深线流活动都有可能影响软泥的类型,但等深线流的改造作用最重要。本文进一步证实沉积堤是等深线流长期作用的产物,并自渐新世形成以来长期保持稳定。     

有效的正压原始方程拟能守恒保真（拟）谱模式

本工作遵循保真计算原理与方法,对正压原始方程气象传统全球（拟）谱模式方案进行改造,构造了正压原始方程拟能完全守恒（拟）谱模式新型保真计算方案,解决了正压原始方程的（非线性）计算稳定性问题和拟能守恒整体性质保持问题,改进了相应正压原始方程气象传统全球（拟）谱模式方案的计算效能。新型保真方案的数值实验表明,计算实践中,新方案在解决拟能守恒问题的同时,可解决（非线性）计算稳定问题,并在一定条件下可解决非线性计算收敛性问题。进一步的比较数值实验还表明,计算实践中,新型保真计算方案在提高相应气象传统方案的计算精度、     

Dispersion and feeding of larval herring (Clupea harengus L.) in the Moray Firth during September 1985

A plume of herring larvae dispersing from a spawning site at Clythness in the Moray Firth (northern Scotland) was surveyed during early September 1985. Several cohorts of larvae were evident from the length distributions, and these were arranged in order of increasing length (age) towards the south-west. The spacing of cohort centres indicated a drift rate of 1–2 km day⁻¹.Calanoid copepod nauplii constituted the major proportion of the diet of larvae <10 mm sampled during the study. Cyclopoid copepod nauplii and gastropod veligers were not found in the diet although they were present in the water. The distribution of nauplii in the region was inversely correlated with the concentration of phytoplankton chlorophyll, and nauplii concentrations were above average in the vicinity of the herring spawning site. The drift trajectory of the herring larvae took them towards an area of high copepodite and adult copepod concentration—items which formed an increasing part of the diet of larger (older) larvae.     

Seasonal and inter-annual variation in occurrence and biomass of rooted macrophytes and drift algae in shallow bays

Submerged rooted macrophytes and drift algae were studied in shallow (0–1 m) brackish soft-bottom bays in the Åland Islands, N Baltic Sea, in 1997–2000. The study was performed by aerial photography and ground-truth sampling and the compatibility of the methods was evaluated. The study provided quantitative results on seasonal and inter-annual variation in growth, distribution and biomass of submerged macrophytes and drift algae.On an average, 18 submerged macrophyte species occurred in the studied bays. The most common species, by weight and occurrence, were Chara aspera, Cladophora glomerata, Pilayella littoralis and Potamogeton pectinatus. Filamentous green algae constituted 45–70% of the biomass, charophytes 25–40% and vascular plants 3–18%. A seasonal pattern with a peak in biomass in July–August was found and the mean biomass was negatively correlated with exposure. There were statistically significant differences in coverage among years, and among levels of exposure. The coverage was highest when exposure was low. Both sheltered and exposed bays were influenced by drift algae (30 and 60% occurrence in July–August) and there was a positive correlation between exposure and occurrence of algal accumulations. At exposed sites, most of the algae had drifted in from other areas, while at sheltered ones they were mainly of local origin.Data obtained by aerial photography and ground-truth sampling showed a high concordance, but aerial photography gave a 9% higher estimate than the ground-truth samples. The results can be applied in planning of monitoring and management strategies for shallow soft-bottom areas under potential threat of drift algae.