An overview of the Oyashio ecosystem

The Oyashio shelf region and the seasonally ice-covered areas north of Hokkaido are highly productive, supporting a wide range of species including marine mammals, seabirds and commercially important species in the western subarctic Pacific. The fishes include gadids, such as walleye pollock and Pacific cod, and subarctic migratory pelagic fishes such as chum salmon and pink salmon. It is also an important summer feeding ground for subtropical migrants such as the Japanese sardine, Japanese anchovy, Pacific saury, mackerels, Japanese common squid, whales and seabirds. In recent decades, some components of the Oyashio ecosystem (i.e., phytoplankton, mesozooplankton, gadid fish, and subtropical migrants) have shown changes in species abundance or distribution that are correlated with environmental changes such as the 1976/1977 and 1988/1989 regime shifts. The First Oyashio Intrusion moved northward from the mid-1960s until the late 1970s, when it moved southward until the 1980s, after which it returned to the north again after the mid-1990s. The sea-surface temperature in spring decreased after the late 1970s, increased after the late 1980s, and remained high during the 1990s. The extent of ice cover in the Sea of Okhostk also decreased during the latest warming in the 1980–1990s but has increased again since the late 1990s. This and other variabilities affect the Oyashio ecosystem and the surrounding region.     

末次冰盛期后黄河三角洲沉积物的磁性特征及其沉积环境

On the basis of measuring the magnetic parameters of sediment in Core YDZ1, combined with a grain size analysis and Carbon-14 dating, the magnetic properties of sediment and sedimentary environment in the Huanghe(Yellow River) Delta area after the last glacial maximum have been studied. The results show that the ferrimagnetic minerals of a pseudo single domain and multi domain particles dominate the magnetic properties of sediment in Core YDZ1. The imperfect anti ferrimagnetic minerals have more contribution on sediment in a depth of 24.0–22.1 m, and more stable-single domain and pseudo single domain particles exist. The susceptibility of anhysteretic remanent magnetization and the ratio of the susceptibility of anhysteretic remanent magnetization to saturation isothermal remanent magnetization show a decrease trend below depth of 24 m, a marked increase trend in a depth of 24.0–13.5 m, and a rapid decrease at depth of 13.5 m, then a fluctuation trend upward. The above two magnetic parameters and the ratio of the susceptibility of anhysteretic remanent magnetization to the mass susceptibility can be regarded as the proxy indicators for the content of clay(4 μm)and the fine-grained size(32 μm). The sedimentary environment after the last glacial maximum in the Huanghe Delta area has experienced the fluvial facies, the tidal flat facies, the neritic facies, the pro delta facies, the delta front facies and the floodplain facies. Thickness of the Holocene transgression layer is 10.5 m and the depth of substrate is about 24 m according to the YDZ1 core. The sedimentary dynamic has a variation trend with strongweak-strong, which has been proved by the Flemming triangular schema.     

Hydraulic properties of concentrated flow of a bank gully in the dry‐hot valley region of southwest China

To quantify spatiotemporal variation in hydraulic properties of bank gully concentrated flow, a series of scour experiments were run under water discharge rates ranging from 30 to 120 l min^?1. Concentrated flows were found to be turbulent and supercritical in the upstream catchment area and downstream gully beds. As discharge increased, values of the soil erosion rate, Reynolds number (Re), shear stress, stream power, and flow energy consumption (ΔE) increased while values of the Froude number (Fr) and the Darcy–Weisbach friction factor (resistance f ) did not. With the exception of gully headcut collapse under discharge rates of 60, 90, and 120 l min^?1, a declining power function trend (P < 0.05) in the soil erosion rate developed in the upstream catchment area, headcuts, and downstream gully beds. However, increasing trends were observed in temporal variations of hydraulic properties for downstream gully beds and the upstream catchment area. Despite significant differences in temporal variation between the soil erosion rate and hydraulic property values, relative steady state conditions of the soil erosion rate and ΔE were attained following an initial period of adjustment in the upstream catchment area, headcuts, and downstream gully beds under different discharge rates. A logarithmic growth of flow energy consumption per unit soil loss (ΔE_u) was observed in bank gullies and the upstream catchment area as the experiment progressed, further illustrating the actual reason behind the discrepancy in temporal variation between soil erosion rates and ΔE. Results demonstrate that ΔE can be used to estimate headcut erosion soil loss, but further quantitative studies are required to quantify coupling effects between hydraulic properties and vertical variation in soil mechanical properties on temporal variation for bank gully soil erosion rates. Copyright © 2015 John Wiley & Sons, Ltd.     

基于Voronoi的海洋底质区域划界方法研究

在对Voronoi特性进行分析的基础上,运用Delaunay规则实现了海洋底质数据点的三角网化,从而间接生成了Voronoi图,再经过邻近区域的合并处理得到理想的底质划界区域。     

打滑地层新型孕镶金刚石钻头

在分析打滑地层特点的基础上,指出了钻进该地层所存在的问题,提出了用于打滑地层钻进的新型孕镶金刚石钻头的设计思路,在钻头工作层中采用主、辅两种磨料,并对这两种磨料的工作机理、处理工艺以及该新型钻头的制造进行了阐述.钻头的室内钻进试验结果表明:在钻进极坚硬致密的锆刚玉时,相对于普通金刚石钻头,新型孕镶金刚石钻头的钻进时效提高1.93倍,平均磨损量增加38%,具有高时效、相对寿命长的优点,是打滑地层钻进的理想钻头.     

广西原状红粘土力学性状与水敏性特征

对广西原状红粘土的力学指标、胀缩特性与孔径分布随脱湿过程的演化规律进行了较为系统的室内试验研究。结果表明：广西原状红粘土为裂隙发育的硬塑性粘土,不同脱湿阶段的力学指标与胀缩性能在较高含水量范围内受基质吸力控制,在较低的含水量范围内主要受控于裂隙性;转折点处含水量与重型击实(干法备样)最优含水量相接近;原状红粘土的孔隙主要以孔径从0.01 μm～0.05 μm的小孔隙为主,在脱湿过程中,干密度增大,总孔隙体积减小,以0.01 μm～0.05 μm与0.1 μm～1.0 μm两个区间内孔隙体积减小最为明显。     

空间刚架结构极限强度分析

本文用理想结构单元法对空间刚架结构进行了极限强度分析，理想结构单元法在于将结构分成最大可能的单元。以简单的形式归并几何非线性与材料非线性。按增量形式加载，直到达到极限强度。本文根据Ｒａｓｈｅｄ理论导出了对称的切向方程组，节省了存贮单元、改善了破坏准则的描述。算例结果与非线性有限单元法结果十分吻合。     

Morphology and Luminosity Segregations in Galaxy Groups

We study morphology and luminosity segregation of galaxies in groups. We analyze the two catalogs of (∼2×400) groups which have been identified in the Nearby Optical Galaxy sample, by means of hierarchical and percolation `friends-of-friends' methods. We find that earlier-type (brighter) galaxies are more clustered and lie closer to the group centers, both in position and in velocity, than later-type (fainter) galaxies. Spatial segregations are stronger than kinematical segregations. These effects are generally detected at the ≳3-sigma level, with the exception of morphological segregation in velocity, which is the weakest effect. Our main results are confirmed by the analysis of statistically more reliable groups (with at least five members), and are strengthened by the detection of segregation in both hierarchical and percolation catalogs. Luminosity segregation is shown to be independent of morphology segregation. Our conclusions agree with a continuum of segregation properties of galaxies in systems, from low-mass groups to massive clusters. This revised version was published online in July 2006 with corrections to the Cover Date.     

海洋铁锰结壳中碲的富集过程研究进展

碲(Te)元素在工业生产中被广泛应用,但在地壳中含量极低,在海洋铁锰结壳中高度富集。评述了海洋铁锰结壳中Te富集过程的相关研究,结果表明: Te在全球海洋中的分布存在空间差异,其中印度洋东经90°海岭铁锰结壳中的Te含量表现出由南向北逐渐升高的特征; 铁锰结壳中更古老壳层的Te含量更高,结壳中Te的物质通量会随壳层生长速率的变化而改变; Te以多种形式赋存在铁锰结壳中,且来源具有多源性,主要通过物理过程和化学过程进入结壳。研究有助于促进分散元素海底成矿理论的发展。