四维变分同化方法在台风初始化及其数值模拟中的应用--对9608号(Herb)台风的研究结果

The MM5 and its four dimensional variational data assimilation (4D-Var) system are used in this paper. Based on the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data, the authors generate an optimal initial condition for a typhoon by using the bogus data assimilation (BDA) scheme. BDA is able to recover many of the structural features of typhoons including a warm-core vertex, the correct center position, and the strong circulation.As a result of BDA using a bogus surface low, dramatic improvement is achieved in the 72 h prediction of typhoon Herb. Through several cases, the initialization by BDA effectively generates the harmonious inner structure of the typhoon, but which is lacking in the original analysis field. Therefore the intensity forecast is improved greatly. Some improvements are made in the track forecast, but more work still needs to be done.     

A New Ornithocheirid from the Early Cretaceous of Liaoning Province, China

Based on a nearly complete skeleton with skull from the Early Cretaceous of Liaoning Province, a new ornithocheirid pterosaur: Boreopterus cuiae gen. et sp. nov. is erected. Boreopterus cuiae is different from other pterosaurs preserved with skulls known from the western Liaoning Province and its neighboring areas. Tiffs new oterosaur has more and larger teeth than those in other ornithocheirids. Its anterior nine pairs of teeth are larger than other teeth. The fourth pair of upper and lower teeth are slightly larger than the third pair. Overall, Boreopterus cuiae shows much small range of tooth size variation than Anhanguerapiscator and Coloborhynchus robustus. The new taxon shares with other ornithocherids in having a relatively large size of the third and fourth pairs of teeth.     

Enrichment of Cd and Pb and associations with grain size in sediments in Nanjing alluvial island of Yangtze River

Intermittence belts of metal contaminated sediment have been formed along the urban riverside of the Yangtze River because of rapid urbanization and industrial development during the last three decades. Baguazhou Island, the third alluvial island in the lower reaches of the Yangtze River, was chosen to assess the contaminations level of Cd, Pb, Ni, Cr, Cu and Zn in suspended particulate matter （SPM）, recent sediments and sediment-derived soils. The relations between the metal concentrations and the grain size distributions in sediments were analyzed in order to explore the association of heavy metal settling with sediment deposition. The results showed that significantly high levels of Cd and Pb in SPM dominated enrichment factors （EFs） of recent sediments in the area of Baguazhou Island. High levels of Cd and Pb were found both in the riverine sediments and in the soils. However, the average levels of Cd and Pb in sediments were almost as twice as those in soil. About 43% of all sediment samples have EFCd≥1.5 and 14% with EFCd≥2. There are about 21% of the samples with EFPb≥1.5 and none of them has EFPb≥2. Meanwhile, soil samples with EFCd≥1.5 account for 39% of all 64 samples and no one with EFPb≥1.0. Most of the sediment samples contain more than 80% of fine grains lower than 60 μm in size, and few samples located in the site where flow eroding process dominates contain fine grains lower than 30%. Correlation analysis indicated that the concentrations of Cd and Pb in the sediments have significant relationships with grain size.     

华南上石炭统船山组中核形石的地质与经济意义

华南上石炭统船山组中普遍发育大量俗称“船山球”的核形石。这种核形石以其分布范围广、数量多、沉积厚度大和特征相似而成为地质历史上一种独特的时装相(Fasion facies)。 笔者通过对华南上石炭统44条地质剖面的实测,800多块光片、薄片的观察及适量的扫描电镜和化学分析发现,这种核形石的内部结构、构造十分复杂,并非过去所认为的属单一的“葛万藻核形石”。根据其形状和动植物的组合,可以区分出许多种类型。含核形石的沉积物主要形成于多滩(岛)的沉积环境中,但核形石也并非以前所说的仅仅出现于单一的滩相环境,它们可以出现于潮下低能带和泻湖。     

贵州煤中汞的分布,赋存状态及对环境的影响

对贵州省六枝、水城、盘县和贵阳等４大煤田煤中汞的研究表明：煤中汞的平均含量为０．５５２μｇ／ｇ;煤中汞主要赋存于黄铁矿中,硅酸盐矿物相中汞的分布量很少;贵州燃煤引起的汞污染问题非常严重。     

海南岛西部早古生代裂陷槽

海南岛西部军营－和盛地区，分布着一套含变质基性、超基性火山岩的浅变质岩系。该岩系具有深水复量式沉积特征，时代属晚奥陶世而不是石炭尼，变质火山岩主要为科马提岩系，部分为拉斑玄武岩，因此，该套岩系不能作为海南岛西部海西地槽或海南岛晚古生代大陆裂谷的依据。综观其时代归属、沉积特征和火山岩特征，表明海南岛西部着早古生代裂陷槽。     

逾渗与岩石破裂的计算机模拟研究

用计算机模拟方法研究了岩石破裂的逾渗模型，给出了在微裂隙随机分布情况下破裂集团的分布图象、破裂集团的大小分布规律、总破裂集团数、集团平均大小、ｂ值、逾渗分维Ｄ及临界情形。所得结果与其他模型和实验基本一致，表明通渗模型是描述岩石破裂扩展演化过程的一种较合适的模型。还发现了岩石破裂过程存在的两个转折点，深入研究这两个转折点附近岩石的宏观性质，可为探索地震孕育演化过程的前兆性质提供依据。     

钻孔灌注桩水下灌注时砼在环空中流动阻力计算方法的探讨

本文拟应用流体力学和砼的流变特性的原理，从理论上探讨砼在环空中流动阻力的计算方法。