基于XML的实时海洋数据传输网络系统

近年来,在海洋灾害预测、预报等海洋信息产品的开发中,对准确、大量、连续、实时的海洋要素监测数据的依赖性日趋增强。同时,由于海洋数据的复杂性,数据来源的多源性,数据平台异构,数据格式不规范等原因,增大了数据集成的难度,降低了数据使用的效率。文章提出了用XML作为传输媒介,结合Socket网络通信技术,建立实时海洋数据传输网络系统,实现了海洋数据集成与交换格式的统一,屏蔽了影响海洋数据集成和使用效率的因素。文章对XML在海洋信息产品开发中的应用做出了有益的探索和尝试,旨在促进XML在我国海洋信息领域的应用。     

The three-dimensional power spectrum of dark and luminous matter from the VIRMOS-DESCART cosmic shear survey

We present the first optimal power spectrum estimation and three-dimensional deprojections for the dark and luminous matter and their cross-correlations. The results are obtained using a new optimal fast estimator, deprojected using minimum variance and Singular Value Decomposition (SVD) techniques. We show the resulting 3D power spectra for dark matter and galaxies, and their covariance for the VIRMOS-DESCART weak lensing shear and galaxy data. The survey is most sensitive to non-linear scales   k _NL∼ 1 h Mpc⁻¹  . On these scales, our 3D power spectrum of dark matter is in good agreement with the RCS 3D power spectrum found by Tegmark & Zaldarriaga. Our galaxy power is similar to that found by the 2MASS survey, and larger than that of SDSS, APM and RCS, consistent with the expected difference in galaxy population.
We find an average bias   b = 1.24 ± 0.18  for the I -selected galaxies, and a cross-correlation coefficient   r = 0.75 ± 0.23  . Together with the power spectra, these results optimally encode the entire two point information about dark matter and galaxies, including galaxy–galaxy lensing. We address some of the implications regarding galaxy haloes and mass-to-light ratios. The best-fitting 'halo' parameter   h ≡ r / b = 0.57 ± 0.16  , suggesting that dynamical masses estimated using galaxies systematically underestimate total mass.
Ongoing surveys, such as the Canada–France–Hawaii Telescope Legacy Survey, will significantly improve on the dynamic range, and future photometric redshift catalogues will allow tomography along the same principles.     

Rotation in gravitational lenses

Gravitational lensing deflects light. A single lens deflector can only shear images, but cannot induce rotations. Multiple lens planes can induce rotations. Such rotations can be observed in quadruply imaged sources, and can be used to distinguish between two proposed solutions of the flux anomaly problem: substructures in lensing galaxies versus large-scale structure. We predict the expected amount of rotation due to large-scale structure in strong lensing systems, and show how this effect can be measured using ∼mas very long baseline interferometry astrometry of quadruple lenses with extended source structures. The magnitude of rotation is around 1°. The biggest theoretical uncertainty is the power spectrum of dark matter on very small scales. This procedure can potentially be turned around to measure the dark matter power spectrum on very small scales. We list the predicted rms rotation angles for several quadruple lenses with known lens and source redshifts.     

昆明和北京两幢建筑物表面热力效应的观测对比

利用昆明、北京两座城市内建筑物为研究对象, 对其不同朝向外墙壁面、屋顶面表面温度及壁面近旁气温进行了观测, 分析了建筑物外墙壁面表面温度及其近旁气温的垂直分布以及壁面、屋顶对周围大气的热力效应特征, 并对两座城市内建筑物的热力状况进行了比较分析。研究表明:建筑物表面温度受太阳辐射的影响要比近旁气温大得多, 一般说来, 壁面昼间是热源, 夜间是热汇; 受研究对象所在的大区域气候、人类活动等影响, 建筑物外表面的热力效应有许多异同; 建筑物屋顶面与近旁空气间的平均热通量基本为正值, 呈现较强的热源效应, 其热力效应强度与太阳辐射呈现正相关; 城市建筑物的外表面 (壁面、屋顶面) 已成为城市区域内有别于城市地面, 且对城市立体气候的形成具有不可忽视影响的热力作用面。     

Numerical modelling of railway ballast at the particle scale

The paper describes the development of a technique to simulate triaxial tests on specimens of railway ballast numerically at the particle scale and its validation with reference to physical test data. The ballast particles were modelled using potential particles and the well‐known discrete element method. The shapes of these elemental particles, the particle size distribution and the number of particles (N = 2800) in each numerical triaxial specimen all matched closely to the real ballast material being modelled. Confining pressures were applied to the specimen via a dynamic triangulation of the outer particle centroids. A parametric study was carried out to investigate the effects on the simulation of timestep, strain rate, damping, contact stiffness and inter‐particle friction. Finally, a set of parameters was selected that provided the best fit to experimental triaxial data, with very close agreement of mobilized friction and volumetric strain behaviour. Copyright © 2015 John Wiley & Sons, Ltd.     

Vegetation changes in the southern Pyrenean flank during the last millennium in relation to climate and human activities: the Montcortès lacustrine record

We report vegetation changes of the last millennium inferred from palynological analysis of a sediment core from Lake Montcortès, situated at ~1,000 m elevation in the southern pre-Pyrenean flank. The record begins in the Middle Ages (~AD 800) and ends around AD1920, with an average resolution of ~30 years. The reconstructed vegetation sequence is complex and shows the influence of both climate and humans in shaping the landscape. Pre-feudal times were characterized by the presence of well-developed conifer forests, which were intensely burned at the beginning of feudal times (AD 1000) and were replaced by cereal (rye) and hemp cultivation, as well as meadows and pastures. In the thirteenth century, a relatively short period of warming, likely corresponding to the Medieval Warm Period, was inferred from the presence of a low Mediterranean scrub community that is today restricted to <800 m elevation. This community disappeared during Little Ice Age cooling in the fifteenth century, coinciding with a decline in human activities around the lake. Forest recovery began around AD 1500, at the beginning of the Modern period, coinciding with wetter climate. Forests, however, declined again during the seventeenth century, coinciding with maximum olive and hemp cultivation. This situation was reversed in post-Modern times (nineteenth century), characterized by an intense agricultural crisis and a significant decline in population that favored forest re-expansion. Correlations with nearby Estanya Lake, situated about 350 m below, provide a regional picture of environmental change. Besides some climate forcing evident in both sequences, human activities seem to have been the main drivers of landscape and vegetation change in the southern Pyrenean flank, in agreement with conclusions from other studies in high-mountain environments.     

新疆西天山达鲁巴依蛇绿岩地质特征

新疆西天山达鲁巴依达坂一带发现的震旦系蛇绿岩，位于塔里木板块北部大陆边缘与伊犁地块的缝合线上，被命名为达鲁巴依蛇绿岩，呈残块状分布于那拉提南缘断裂南侧的构造混杂带中，剖面出露较好，岩石化学、地球化学特征显示为大洋岛屿环境，是震旦纪晚期伊犁地块从塔里木板块裂解时的产物．     

清江石门地区第四纪冰川沉积与岩溶发育期的探讨

通过对区内第四纪堆积物的研究,为本区岩溶发育期的划分提供了重要依据。丘顶第四纪冰川堆积物的确定,并结合邻近区域古气候环境演变特征,认为大姑-庐山间冰期是本区岩溶地貌基本格架的形成时期。古水文网与岩性是制约岩溶发育的主要因素。同时认为用地文期和阶地来划分岩溶发育期是不合适的。