小直径组合桩的波浪力实验分析

本文给出小直径孤立桩、两个桩和2×2个桩的波浪作用力实验结果。在波浪水槽中以0°,45°,90°三个波浪方向测量了各桩所受的纵向力和横向力,文中讨论了组合桩之间的干扰效应,给出了干扰系数随KC数和桩距的变化。     

一种改进的膜盐度计

叙述了一种可用于现场及实验室使用的新的浸入式电池膜盐度计的设计与结构。该膜盐度计传感器由下列电化学电池组成,用此传感器与微机或pH/离子计配合组成了膜盐度计。该仪器可用于近岸河口地区表层海水盐度监测并用于有潮河口底栖动物生态现场研究。仪器现场条件使用准确度约为盐度测量值1％。同时能用于Cl~-及其他离子的现场监测。     

剔除高密度电阻率法三极装置浅部不均匀体效应影响的方法及效果

基于总结出的高密度电阻率法三极测量装置下的二维正演拟断面中浅部不均匀体畸变规律和特征,设计了一套能有效剔除三极测量装置浅部不均匀体效应影响的数据处理方法,成功应用于野外实测数据的处理。     

基于Membrane MRF模型的SAR图像贝叶斯去斑

SAR图像可以看作是真实反映地物后向散射特性的无噪图像与相干斑噪声的乘积,通过贝叶斯估计从图像观测值估计出图像真值即可去除相干斑.而贝叶斯去斑的关键在于建立能与SAR图像特性相匹配的先验信息模型.用MembraneMRF模型对先验信息建模,克服了以往所用GMRF模型对参数估计十分敏感的问题,并通过对该模型邻域结构的自适应调整来分类处理处于匀质区域和含结构特征区域的像元,在有效抑制相干斑的同时较好地保持图像的结构特征.仿真和实际SAR图像数据的实验结果,验证了所提方法的有效性.     

Mineral composition variation in Alpine Schist, Southern Alps, New Zealand: Implications for recrystallization and exhumation

Abstract Compositional variation of silicates (plagioclase, K-feldspar, epidote, titanite, garnet, white mica, biotite, chlorite), ilmenite, carbonates (calcite, ankerite) and apatite, in quartzofeldspathic lithologies of the Alpine Schist, New Zealand, is discussed in terms of increasing metamorphic grade and possible isograd-producing reactions. The mineral data, in conjunction with geological considerations, are used to determine polychronous P-T arrays of an early high P/T event (c. 16°C/kb; 5°C/km) overprinted by a lower P/T event (c. 50°C/kb; 15°C/km) that provides an estimation of Mesozoic and Cenozoic exhumation of schist of 11 to 13 km and 19 to 22 km respectively. The effects of possible shear heating and recrystallization to form K-feldspar zone schist near the Alpine Fault is consistent with movement along a mid to lower crustal detachment surface during Cenozoic shortening, and near isothermal exhumation of the schists to form the Southern Alps.     

Der Leitfähigkeitstest — Ein Testsystem zur Ermittlung der membrantoxischen Eigenschaften von Substanzen

The Conductivity Test — Determining the Membrane-toxic Properties of Substances A new biotest system is introduced which is specific in terms of the measured effect but not in terms of the applied organisms. The system is able to detect the effect of membrane-toxic compounds e.g. detergents, organic solvents, and radical formers. Released into the environment, these substances damage biological membranes and therefore cause ion leakage into a surrounding medium. Ion leakage is taken as a measure for membrane damage and is determined as an increase of the electrical conductivity in the medium (conductivity test). The results presented for the tensides benzalkonium chloride, LAS (linear alkylbenzenesulfonate), and APG (alkylpolyglycoside) demonstrate the capability of the conductivity test to distinguish between the differing toxicological potential of these membrane-toxic substances. In contrast to most of the conventional biotests, the endpoint of the conductivity test is independent of a specific organism. This independence is demonstrated by the results obtained with benzalkonium chloride treatment of Elodea canadensis, Lemna minor, and Salvinia natans. The conductivity test represents a versatile, easy to handle biotest system for the assessment of ecotoxicological effects caused by membrane-toxic substances.     

Evolution of accelerographs, data processing, strong motion arrays and amplitude and spatial resolution in recording strong earthquake motion

This paper presents a review of the advances in strong motion recording since the early 1930s, based mostly on the experiences in the United States. A particular emphasis is placed on the amplitude and spatial resolution of recording, which both must be ‘adequate’ to capture the nature of strong earthquake ground motion and response of structures. The first strong motion accelerographs had optical recording system, dynamic range of about 50 dB and useful life longer than 30 years. Digital strong motion accelerographs started to become available in the late 1970s. Their dynamic range has been increasing progressively, and at present is about 135 dB. Most models have had useful life shorter than 5–10 years. One benefit from a high dynamic range is early trigger and anticipated ability to compute permanent displacements. Another benefit is higher sensitivity and hence a possibility to record smaller amplitude motions (aftershocks, smaller local earthquakes and distant large earthquakes), which would augment significantly the strong motion databases. The present trend of upgrading existing and adding new stations with high dynamic range accelerographs has lead to deployment of relatively small number of new stations (the new high dynamic range digital instruments are 2–3 times more expensive than the old analog instruments or new digital instruments with dynamic range of 60 dB or less). Consequently, the spatial resolution of recording, both of ground motion and structural response, has increased only slowly during the past 20 years, by at most a factor of two. A major (and necessary) future increase in the spatial resolution of recording will require orders of magnitude larger funding, for purchase of new instruments, their maintenance, and for data retrieval, processing, management and dissemination. This will become possible only with an order of magnitude cheaper and ‘maintenance-free’ strong motion accelerographs. In view of the rapid growth of computer technology this does not seem to be (and should not be) out of our reach.     

An effect of closure on the structure of principal components

The principal components transformation generates, from any data array, a new set of variables—the scores of the components—characterized by a total variance exactly equal to that of the initial set. It is in this sense that the transformed variables are said to contain, preserve, or account for, the variance of the original set. The scores, however, are uncorrelated. In the course of the transformation, what becomes of the strong interdependence of variance and covariance so characteristic of closed arrays? The question seems to have attracted little attention; we are aware of no study of it in the earth sciences. Experimental work reported here shows quite clearly that the overall equivalence of variance and covariance imposed by closure, though absent from the component scores,may emerge in relations between the coefficientsof each of the lower-order components; if the raw data are complete rock analyses, the sum of all the covariances of the coefficients of such a component is negative, and is very nearly equal to the sum of all the variances in absolute value. (In all cases so far examined, the absolute value of the first sum is a little less than that of the second.) The principal components transformation provides an elegant escape from closure correlation if a petrographic problem can be restated entirely in terms of component scores, but not if a physical interpretation of the component vectors is required.     

Continuous inline mapping of a dissolved methane plume at a blowout site in the Central North Sea UK using a membrane inlet mass spectrometer – Water column stratification impedes immediate methane release into the atmosphere

The dissolved methane (CH₄) plume rising from the crater of the blowout well 22/4b in the Central North Sea was mapped during stratified water column conditions. Geochemical surveys were conducted close to the seafloor at 80.3 m water depth, below the thermocline (61.1 m), and in the mixed surface layer (13.2 m) using membrane inlet mass spectrometry (MIMS) in combination with a towed CTD. Seawater was continuously transferred from the respective depth levels of the CTD to the MIMS by using an inline submersible pump. Close to the seafloor a well-defined CH₄ plume extended from the bubble release site ∼460 m towards the southwest. Along this distance CH₄ concentrations decreased from a maximum of 7872 nmol l⁻¹ to less than 250 nmol l⁻¹. Below the thermocline the well-defined CH₄ plume shape encountered at the seafloor was distorted and filaments were observed that extended towards the west and southwest in relation to current direction. Where the core of the bubble plume intersected this depth layer, footprints of high CH₄ concentrations of up to 17,900 nmol l⁻¹ were observed. In the mixed surface layer the CH₄ distribution with a maximum of up to 3654 nmol l⁻¹ was confined to a small patch of ∼60 m in diameter. The determination of the water column CH₄ inventories revealed that CH₄ transfer across the thermocline was strongly impeded as only ∼3% of the total water column inventory was located in the mixed surface layer. Best estimate of the CH₄ seabed release from the blowout was 1751 tons yr⁻¹. The fate of the trapped CH₄ (∼97%) that does not immediately reach the atmosphere remains speculative. In wintertime, when the water column becomes well mixed as well as during storm events newly released CH₄ and the trapped CH₄ pool can be transported rapidly to the sea surface and emitted into the atmosphere.