浅谈城市高层建筑施工的沉降观测

目前城市高层建筑越来越多,它的使用安全性也随之受到人们的关注。对城市高层建筑垂直沉降观测进行了详尽的阐述,介绍了沉降基准点、观测点的布设与设计原则,沉降观测的方法与施测精度,建筑物的沉降趋势以及观测成果的整理与分析,并进行了实例分析,对实际工作应用具有一定的参考价值。     

Pelagic records from the Equatorial Ninetyeast Ridge and significant environmental events during the past 3.5 Ma

This paper presents pelagic records of planktic foraminifera, as well as data of stable isotope stratigraphy and carbonate stratigraphy since 3.5 Ma B.P. from site ODP758 in the Ninetyeast Ridge of the Indian Ocean. Based on these data, manifestations and related mechanisms of major tectonic and environmental events such as the rapid uplift of the Himalaya Mountains, “middle Pleistocene climatic transition” and “mid-Brunhes dissolution event” in the region are discussed. According to the analysis and comparison of various indices and changes in terms of foraminifera assemblage, paleotemperature, paleosalinity and themocline from site ODP758, the authors deduce that the paleoclimatic changes might correlate with the mid-Pleistocene transition at 1.4–1.7 Ma B.P. The changes of CaCO₃, mass accumulation rates (MAR) of CaCO₃ and non- CaCO₃ MAR indicate that the loaded terrigenous sediments increased at 1.7 Ma, which is in agreement with the uplift history of the Qinghai-Tibet plateau as shown by the available data. The last two changes coincide with the uplift of the Qinghai-Tibet plateau, hence they are called “Qinghai-Tibet movement” (1.7 Ma), and the “Kunlun-Yellow River movement” (1.2–0.6 Ma). The changes of the CaCO₃ content, coarse fraction (> 150 μm) content and planktonic foraminifera biostratigraphy show that strong dissolution of abyssal CaCO₃ occurred in the study region during 0.5–0.4 Ma. The event was consistent with the “mid-Brunhes dissolution event” in the sedimentary records of the Atlantic Ocean, Pacific Ocean, Indian Ocean and Nansha sea area of the South China Sea. __________ Translated from Geological Bulletin of China, 2007, 26(12): 1627–1632 [译自: 地质通报]     

中国海相探矿权区块定量评价方法

在研究了我国海相油气探矿权区块基本油气地质条件、勘探程度、技术经济条件等要素和特点的基础上,给出了48个评价参数和归一化取值参照表,建立了探矿权区块评价工作流程、评分参数及计算公式。提出对我国海相勘探层探矿权区块评价应该注意:与国外海相碳酸盐岩评价的差别;与国内陆相碎屑岩评价的差别;成藏组合的划分;评价内容的有效性、不确定性和评价参数的可信度;成败经验的总结和勘探程度的研究。     

基于VRS的GPS测量误差分析

系统误差包括卫星轨道误差、卫星钟差、接收机钟差及大气折射误差等。是GPS测量的主要误差源。但系统误差通常可以采用适当的方法来减弱或消除,如建立误差改正模型对观测值进行改正,或选择良好的观测条件,采用适当地观测方法,进行线性差分等.本文介绍了基于VRS的GPS测量要解决的一个主要问题即在系统运行中产生的各种误差进行改正,使之减小或者消除。并就影响VRS精度的各种误差予以分析     

Multiple outlier detection by evaluating redundancy contributions of observations

When applying single outlier detection techniques, such as the Tau () test, to examine the residuals of observations for outliers, the number of detected observations in any iteration of adjustment is most often more numerous than the actual number of true outliers. A new technique is proposed which estimates the number of outliers in a network by evaluating the redundancy contributions of the detected observations. In this way, a number of potential outliers can be identified and eliminated in each iteration of an adjustment. This leads to higher efficiency in data snooping of geodetic networks. The technique is illustrated with some numerical examples.     

“全新特提斯洋”概念与广义特提斯构造域

特提斯最初是指欧亚大陆南缘的古海洋，后逐渐引申出从元古宙、古生代到中生代的一系列位于劳亚大陆与冈瓦纳大陆之间的古大洋，如原特提斯洋、古特提斯洋和新特提斯洋，不同大洋在时间上前后交叠。如今横亘在冈瓦纳大陆(南极洲)和欧亚大陆之间的是印度洋，是新特提斯洋的继承者，可以另称为“全新特提斯洋”。这一概念的引申直接体现了印度洋与特提斯构造域一脉相承的关系，有助于将今论古、由此及彼，更直观地了解特提斯构造域的演化过程。本文按时间序列梳理了印度洋的大地构造演化和岩浆作用过程，识别了印度洋在155 Ma、120 Ma、90~84 Ma、76 Ma、65 Ma、52 Ma、45 Ma、38 Ma等关键时期的异常海底扩张记录，这些扩张事件将为标定新特提斯构造域的演化提供参照。其中155 Ma可能指示了新特提斯洋的鼎盛期，90 Ma指示了新特提斯洋的洋中脊俯冲，76~52 Ma是非洲- 阿拉伯大陆与欧亚大陆初始碰撞- 主碰撞(即新特提斯洋西部关闭)的时期，65~45 Ma是印度次大陆与欧亚大陆初始碰撞- 主碰撞(即新特提斯洋中部关闭)的时期，38 Ma是澳大利亚北部大洋开始净俯冲(即新提斯洋东部开始消减)的时间。印度洋扩张历史的研究为理解新特提斯洋消亡提供参考标尺。站在“后方”印度洋的角度，可以更清晰地透视“前线”特提斯构造域的演化过程，为理解板块构造活动规律提供支撑。     

Analysis of 2-d flare spectra: Velocity fields derived from Hα line asymmetries

We derive a time series of two-dimensional velocity fields for a flare region on 1992 December 16, based on the asymmetries of the H line. The H spectra were obtained by an imaging spectrograph at the Solar Tower Telescope of Nanjing University. Four sites with evident chromospheric downflows are found to appear and decay consecutively in the studied region. The value of maximum velocities is 30–40 km s^–1 and the lifetime of downflows is 2–3 min at these sites. It is also shown that the asymmetries only exist at the line wing, while the line center has nearly no shifts for this flare. Finally, we make a discussion on the characteristics of the velocity distribution and its correlations with the intensity distribution, as well as with the hard X-ray emission.     

Oil-generation kinetics for organic facies with Type-II and -IIS kerogen in the Menilite Shales of the Polish Carpathians

The Menilite Shales (Oligocene) of the Polish Carpathians are the source of low-sulfur oils in the thrust belt and some high-sulfur oils in the Carpathian Foredeep. These oil occurrences indicate that the high-sulfur oils in the Foredeep were generated and expelled before major thrusting and the low-sulfur oils in the thrust belt were generated and expelled during or after major thrusting. Two distinct organic facies have been observed in the Menilite Shales. One organic facies has a high clastic sediment input and contains Type-II kerogen. The other organic facies has a lower clastic sediment input and contains Type-IIS kerogen. Representative samples of both organic facies were used to determine kinetic parameters for immiscible oil generation by isothermal hydrous pyrolysis and S₂ generation by non-isothermal open-system pyrolysis. The derived kinetic parameters showed that timing of S₂ generation was not as different between the Type-IIS and -II kerogen based on open-system pyrolysis as compared with immiscible oil generation based on hydrous pyrolysis. Applying these kinetic parameters to a burial history in the Skole unit showed that some expelled oil would have been generated from the organic facies with Type-IIS kerogen before major thrusting with the hydrous-pyrolysis kinetic parameters but not with the open-system pyrolysis kinetic parameters. The inability of open-system pyrolysis to determine earlier petroleum generation from Type-IIS kerogen is attributed to the large polar-rich bitumen component in S₂ generation, rapid loss of sulfur free-radical initiators in the open system, and diminished radical selectivity and rate constant differences at higher temperatures. Hydrous-pyrolysis kinetic parameters are determined in the presence of water at lower temperatures in a closed system, which allows differentiation of bitumen and oil generation, interaction of free-radical initiators, greater radical selectivity, and more distinguishable rate constants as would occur during natural maturation. Kinetic parameters derived from hydrous pyrolysis show good correlations with one another (compensation effect) and kerogen organic-sulfur contents. These correlations allow for indirect determination of hydrous-pyrolysis kinetic parameters on the basis of the organic-sulfur mole fraction of an immature Type-II or -IIS kerogen.     

T -distributed Random Fields: A Parametric Model for Heavy-tailedWell-log Data1

Histograms of observations from spatial phenomena are often found to be more heavy-tailed than Gaussian distributions, which makes the Gaussian random field model unsuited. A T-distributed random field model with heavy-tailed marginal probability density functions is defined. The model is a generalization of the familiar Student-T distribution, and it may be given a Bayesian interpretation. The increased variability appears cross-realizations, contrary to in-realizations, since all realizations are Gaussian-like with varying variance between realizations. The T-distributed random field model is analytically tractable and the conditional model is developed, which provides algorithms for conditional simulation and prediction, so-called T-kriging. The model compares favourably with most previously defined random field models. The Gaussian random field model appears as a special, limiting case of the T-distributed random field model. The model is particularly useful whenever multiple, sparsely sampled realizations of the random field are available, and is clearly favourable to the Gaussian model in this case. The properties of the T-distributed random field model is demonstrated on well log observations from the Gullfaks field in the North Sea. The predictions correspond to traditional kriging predictions, while the associated prediction variances are more representative, as they are layer specific and include uncertainty caused by using variance estimates.