Identification and characterization of 43 microsatellite markers derived from expressed sequence tags of the sea cucumber (Apostichopus japonicus)

The sea cucumber Apostichopus japonicus is a commercially and ecologically important species in China. A total of 3056 potential unigenes were generated after assembling 7597 A. japonicus expressed sequence tags (ESTs) downloaded from Gen-Bank. Two hundred and fifty microsatellite-containing ESTs (8.18%) and 299 simple sequence repeats (SSRs) were detected. The average density of SSRs was 1 per 7.403 kb of EST after redundancy elimination. Di-nucleotide repeat motifs appeared to be the most abundant type with a percentage of 69.90%. Of the 126 primer pairs designed, 90 amplified the expected products and 43 showed polymorphism in 30 individuals tested. The number of alleles per locus ranged from 2 to 26 with an average of 7.0 alleles, and the observed and expected heterozygosities varied from 0.067 to 1.000 and from 0.066 to 0.959, respectively. These new EST-derived microsatellite markers would provide sufficient polymorphism for population genetic studies and genome mapping of this sea cucumber species.     

城市空间智能计算平台研究

该文提出了空间智能平台的概念,阐述了其研究意义和内容,明确了空间智能计算平台核心计算模型的建模对象和目标。在此基础上,分析了宏观数学模型、群体行为模型两种用来构建空间活动模型的建模方法以及适用于空间活动分析的物理环境建模技术。从融合多尺度行为模型、构建城市日常生活模型、验证和校验核心模型以及平衡效率和效果4方面探讨了构建空间智能计算平台的关键技术。从实际功能看,城市空间智能平台是联系宏观复杂问题和微观机制的桥梁,是分析城市问题的工程化实验平台,具有广阔的应用前景。     

Impact of the variation of westerly jets over East Asia on precipitation of eastern China in July

The impact of the northward jump and westward movement of the East Asian westerly jet core from the western Pacific Ocean to the Qinghai-Tibet Plateau on precipitation distribution of eastern China is studied. It is concluded that on the one hand, the northward jump of the jet causes the precipitation belt to move northward from the middle and lower reaches of the Yangtze River valley and withdraw during the Mei-yu season; on the other hand, the westward movement of the jet core has no correspondence with withdrawal of the Mei-yu season. However, the earlier or later occurrence of the westward movement of the jet has an influence on the process of the rain belt moving northward than the northward jump of the jet: the rain belt moves northward from the middle-lower Yangtze River valley to the Huaihe River and then to an area between the Yellow River and Huaihe River during years when the time of the westward movement of the jet core is later than that of the northward jump of the jet and from the middle-lower Yangtze River valley to an area between the Yellow River and Huaihe River in other years. Further analysis shows that: (1) The northward jump of the jet and the westward movement of the East Asian westerly jet core causes significant variation of the general atmospheric circulation in middle latitudes and water vapor transport from the western Pacific, but not from the Bay of Bengal. (2) Impact of the northward jump and the westward movement of the East Asian westerly jet core on circulation are different, therefore, water vapor transport from the western Pacific and its impact on the rain belt are different. The earlier or later occurrence of the westward movement of the jet core than the northward jump of the jet causes the process of circulation and water vapor transport to be different which produces a different process of the rain belt moving northward.     

NNFFC-adaptive output feedback trajectory tracking control for a surface ship at high speed

An adaptive output feedback controller based on neural network feedback-feedforward compensator (NNFFC) which drives a surface ship at high speed to track a desired trajectory is designed. The tracking problem of the surface ship at low speed has been widely investigated. However, the coupling interactions among the forces from each degree of freedom (DOF) have not been considered in general. Furthermore, the influence of the hydrodynamic damping is also simplified into a linear form or neglected. On the contrary, coupling interactions and the nonlinear characteristics of the hydrodynamic damping can never be neglected in high speed maneuvering situation. For these reasons, the influence of the nonlinear hydrodynamic damping on the tracking precision is considered in this paper. Since the hydrodynamic coefficients of the surface ship at high speed are very difficult to be accurately estimated as a prior, it will be compensated by NNFFC as an unknown part of the tracking dynamics system. The stability analysis will be given by the Lyapunov theory. It indicates that the proposed control scheme can guarantee that all the signals in the closed-loop system are uniformly ultimately bounded (UUB), and numerical simulations can illustrate the excellent tracking performance of the surface ship at high speed under the proposed control scheme.     

达陕高速金竹山隧道涌水塌方的综合处治研究

在调查隧道K64 +664～ K64+ 674段涌水塌方特征的基础上,从地质结构和地层岩性分析其成因.相应地,建立综合工作程序,采用”超前双排长管棚+小导管+注浆+三台阶法施工+瓦斯监测”的综合方案.对灾害进行处治,效果明显.     

爆心距对爆破震动信号频谱的影响分析

结合临沂某一隧洞工程,利用matlab分析软件分析了不同爆心距下的爆破震动信号的频谱变化情况。得出：在爆破中近区,震动信号的主频在垂直方向的分量较水平方向大,随着爆心距的增加地面震动峰值速度的主震方向会由水平方向向垂直方向转化,总体呈衰减趋势,震动主频趋向于低频;在爆破参数和爆区特征类似于本工程的工程爆破现场其中低频震动信号在水平方向上的分量所占能量比例高于垂直分量的能量比例,在距爆源较远的位置也不能忽略爆破震动对建筑结构的影响,尤其是要加强水平方向的抗震设防。     

塔里木盆地上泥盆统一下石炭统东河砂岩沉积相与哈得逊油田的发现

哈得逊油田是塔里木盆地最大的整装油田之一,储量规模超过亿吨.在其发现过程中,东河砂岩的沉积相及其相变规律起了重要的指导作用.东河砂岩为晚泥盆世晚期至早石炭世早期海侵背景下沉积的一套海侵砂(砾)岩,主体为滨岸海滩相砂体,在全盆地范围内是一个明显的穿时沉积体.东河砂岩从古地貌低部位向高部位持续超覆变薄,以陆源碎屑滨岸-浅海...     

Mechanism of cultivation soil degradation in rocky desertification areas under dry/wet cycles

Karst rocky desertification is a process of land degradation involving serious soil erosion, extensive exposure of basement rocks. It leads to drastic decrease in soil productivity and formation of a desert-like landscape. In this regard, changes in climatic conditions are the main origin of the soils degradation. Indeed, soils subjected to successive dry/wet cycling processes caused by climate change develop swelling and shrinkage deformations which can modify their water retention properties, thus inducing the degradation of soil–water capacity. The ecological characteristics of cultivation soils in karst areas, Southwest of China, are extremely easy to be affected by external environmental factors due to its shallow bedding and low vegetation coverage. Based on the analysis of the climate (precipitation) of this region during the past decades, an experimental study has been conducted on a cultivated soil obtained from the typical karst area in southwestern China. Firstly, the soil–water properties have been investigated. The measured soil–water retention curve shows that the air-entry value of the soil is between 50 and 60 kPa, while the residual saturation is about 12%. Based on the experimental results, three identifiable stages of de-saturation have been defined. Secondly, a special apparatus was developed to investigate the volume change behavior of the soil with controlled suction cycles. The vapor equilibrium technique was used for the suction control. The obtained results show that under the effect of dry/wet cycles, (1) the void ratio of the cultivated soil is continuously decreasing, leading to a gradual soil compaction. (2) The permeability decreases, giving rise to a deterioration of water transfer ability as well as a deterioration of soil–water retention capacity. It is then obvious that the long-term dry/wet cycling process caused by the climate change induce a continuously compaction and degradation of the cultivated soil in karst rocky desertification areas.     

中国南海涠洲油田W114A平台服役15年的水下钢结构腐蚀防护调查

介绍了W114A平台在南海服役15年的水下钢结构的腐蚀与防护特检报告.检测表明,生物污损严重,最大附着厚度可达20 cm,阴极保护系统正常,保护效果良好.对检测方法和结果进行了分析发现,电位测量程序不妥,牺牲阳极物理尺寸的测量方法不准确,测厚点的基面清理不干净,不能准确地对平台的阴极防护效果进行评估,并对此提出了修改意...     

夏季长江口浮游细菌和浮游病毒的分布特征及环境制约因素

应用荧光显微直接计数法,研究了2006年夏季长江口及邻近海域浮游细菌、浮游病毒数量的分布特征,探讨了它们与环境因子之间的关系.结果表明:(1)浮游细菌数量为(6.92×105～5.54×106)个/mL,浮游病毒数量为(2.22×106～9.97×107)个/mL.浮游细菌和浮游病毒数量的平面分布特征较一致,均为近海过...