水泥固化土新材料在围埝堤心结构中应用研究

采用水泥固化土作为新的充填材料,对于缺少砂土的天津港地区,不仅可以减少砂料长途运输,节省能源,降低工程造价,而且可以充分利用港池和航道开挖的淤泥质粘土。根据室内成型试验、现场监测与检测结果探讨了水泥固化土新材料的工程特性等,为水泥固化土新材料在围埝堤心结构中应用打下了坚实的基础。     

海洋环境中Nd的同位素组成及其地质意义

海水,海洋沉积物中的自生组分,生物壳体乃至全岩的Ｎｄ同位素组成可以反应大洋水体和沉积物的来源及大洋水体循环特征,因而具有重要的地质意义。在综合近２０年来关于现代世界大洋海水,Ｆｅ－Ｍｎ沉积,热液,热液沉积物及其它组分的Ｎｄ同位素的研究资料基础上,总结了不同洋区,不同深度海水的Ｎｄ同位素组成特征及其控制因素;同时,依据Ｆｅ－Ｍｎ结壳及岩心中有孔虫的Ｎｄ同位素组成资料,总结了新生代以来世界海洋中Ｎｄ同     

柴达木盆地北缘赛坝沟金矿床碲化物的发现及其来源探讨

赛坝沟金矿床位于柴北缘赛什腾山—阿尔茨托山成矿带东南段,含金石英脉主要赋存于早奥陶世英云闪长岩的断裂、节理裂隙内.流体成矿过程从早到晚划分为黄铁矿烟灰色石英脉阶段(Ⅰ)、黄铁矿白色石英脉阶段(Ⅱ)、多金属硫化物-灰白色-灰褐色石英脉阶段(Ⅲ)、灰白色石英-方解石脉阶段(Ⅳ).通过矿相学观察、能谱及电子探针分析,在该矿床Ⅱ、Ⅲ阶段矿石中首次发现大量的金/银/铅的碲化物,主要产出在黄铁矿、石英或其裂隙中,矿物生成顺序可初步厘定为黄铁矿→黄铜矿→自然金、碲铅矿→碲金矿→碲金银矿.基于赛坝沟金矿床矿石特征、成矿阶段及铅同位素特征,结合前人围岩及成矿年代学、成矿流体和同位素研究,初步认为矿床中金碲物质来源于早志留世深部地幔和下地壳混熔形成的岩浆流体,成矿流体沿大型剪切带上升,并与地表大气降水混合后在剪切带相对张性及韧脆性转换等构造薄弱部位富集成矿.     

海水营养盐参考物质的国际比对实验

准确可靠的海水营养盐数据是研究海洋生物地球化学过程的重要前提,为增加我国海洋化学实验室与全球其他实验室间的营养盐数据的可比性,本文介绍了厦门大学近海海洋环境科学国家重点实验室参与由国际海洋碳协作计划等海洋机构组织的海水营养盐参考物质的国际比对实验的具体测量过程和测量结果。在5次国际比对实验中（2006—2017年）,本实验室采用基于间隔连续流动分析技术测量海水营养盐参考物质中的硝酸盐、亚硝酸盐、活性磷酸盐和活性硅酸盐,在共计117项比对参数中,本实验室的结果与其他实验室高度可比,获得的满意测量结果高达109项,占比大于90%,且其中88%的测量值与公认的标准值的偏差在1倍的能力评定标准偏差之内,与国际同类实验室相比,本实验室对海水营养盐的测量能力在历年中保持在国际先进行列。本文基于历年国际比对的经验,对如何提升我国对海水、特别是开阔大洋营养盐测量的准确度提出了参考建议,为提高我国对海水营养盐的测量能力达到国际先进水平提供了借鉴。     

Concentrations of Trace Elements in Carbonate Reference Materials Coral JCp-1 and Giant Clam JCt-1 by Inductively Coupled Plasma-Mass Spectrometry

Trace elements in the Geological Survey of Japan carbonate reference materials Coral JCp-1 and Giant Clam JCt-1 were determined by inductively coupled plasma-mass spectrometry after digestion with 2% v/v HNO₃. A standard addition method was adopted in this determination in order to neutralise the Ca matrix effect. In addition, Sc, Y, In and Bi were used as internal standards to control the matrix effect and correct instrumental drift. Of the eighteen elements measured in JCp-1, precisions for fourteen elements, including Cu, Cd and Ba, were better than 10% RSD and concentrations ranged from 0.002 μg g^-1 (Cs) to 8.02 μg g^-1 (Ba). The concentrations of measured trace elements in JCt-1, except for Cu, were lower than those in JCp-1. Precisions for all elements with concentrations higher than 0.04 μg g^-1 in JCt-1 were also better than 10% RSD and concentrations were found to be between 0.001 μg g^-1 (Cs) and 4.84 μg g^-1 (Ba). The concentrations of more than fifteen trace elements in the aragonite reference materials are reported here for the first time. Both reference materials are suitable for use in geochemical studies of environmental reconstruction based upon biogenic carbonate materials.     

Electron Probe Microanalysis of Environmental Samples: Preparation of Reference Materials, Correction for Particle Size Effects and Representative Results on Sediments Recovered from Snow, Power Station Fly Ash and Bone Samples

In this paper we report the results of electron probe X-ray microanalysis (EPMA) that was used to study environmental materials. The mode of preparation and certification of reference samples based on a basaltic glass matrix for environmental applications of EPMA is described. These samples were prepared containing scandium, strontium and barium (from 0.03 up to 7% m/m) and an evaluation was made of homogeneity, their stability to local heating, followed by analysis by independent methods for certification of composition. Matrix correction procedures for the EPMA technique have been developed for particles having a size commensurable with the volume of X-ray generation. An analytical equation for the size factor is proposed and two techniques for selecting optimum conditions for the analysis of environmental samples by EPMA are reported. These procedures provided satisfactory results when utilized in analysing sediments recovered from snow, coal fly ash and the bones of animals and fish, results from which can be used as indicators for evaluating the pollution level of the lower atmosphere, surface and ground water, as well as revealing pollution mechanisms.     

沉积盆地动力学与模拟研究

沉积盆地动力学过程与模拟研究是当前地球科学研究的前沿领域。盆地形成演化的动力学机制、盆地沉积充填过程与模拟、盆地规模的流体动力学等方面的研究近年来取得了重要进展。从定性的静态描述分析转向定量的动态过程研究是当前盆地动力学研究的主要发展趋势。盆地形成机制研究在深部过程控制、多重机制联合作用、幕式裂陷和反转过程等方面取得显著进展。前陆盆地构造—充填过程和模拟、构造活动盆地层序地层学、盆地充填过程分析与模拟等研究代表了盆地充填动力学研究的最新成果。盆地流体过程和模拟是当前的一个研究热点,盆地流体的识别、追踪和盆地规模的流体动力学分析与模拟获得突出性进展。     

Structural vibration control by shape memory alloy damper

A damper device based on shape memory alloy (SMA) wires is developed for structural control implementation. The design procedures of the SMA damper are presented. As a case study, eight such SMA dampers are installed in a frame structure to verify the effectiveness of the damper devices. Experimental results show that vibration decay of the SMA damper controlled frame is much faster than that of the uncontrolled frame. The finite‐element method is adopted to conduct the free and forced vibration analysis of the controlled and uncontrolled frame. The experimental and numerical results illustrate that the developed SMA dampers are very effective in reducing structural response and have great potential for use as efficient energy dissipation devices with the advantages of good control of force and no lifetime limits, etc. Copyright © 2003 John Wiley & Sons, Ltd.     

The infrared colors of main sequence stars: how much circumstellar debris is normal?

We have been awarded NASA Key Project observing time on ISO, in order to establish the true frequency of far-infrared excesses in a volume-limited sample of main sequence and related stars, and address the relative success or failure of single stars in processes related to the forming of planetary systems. For a volume-limited subset of main sequence and related stars, PHT03 measurements at 3.6, 11.5, 20 and 60 micron will be obtained, using a 120 arsec aperture in all cases to eliminate possible companion confusion with differing apertures, to ascertain spectral energy distributions. For the M dwarfs, 100 micron observations will also be obtained. For some, brighter sources, more extensive wavelength coverage and improved spatial resolution will be attempted, using CAM and SWS. Spatially over-sampled PHOT observations will be made at 60 micron of the brightest and nearest Vega-like sources to measure the characteristic sizes of the emitting regions and obtain some information regarding their shapes and orientations. The goal is not a map, but scan profiles along 3 position angles which can be deconvolved to find the intrinsic size and shape of the half-maximum contour of the emitting region. Photometry of selected lines of sight through the zodiacal dust will also be carried out to look for outer solar system (Kuiper Belt) material. Observation at a range of wavelengths, ecliptic latitudes and at 2 epochs is designed to help untangle foreground Zodiacal from background Kuiper flux, not necessarily to look for individual macroscopic objects.     

三维梁-颗粒模型在岩石材料破坏模拟中的应用

用三维梁-颗粒模型BPM3D(beam-particlemodelinthreedimensions)对岩石类非均质脆性材料的力学性质和破坏过程进行了数值模拟。梁-颗粒模型是在离散单元法基础上,结合有限单元法中的网格模型提出的用于模拟岩石类材料损伤破坏过程的数值模型。在模型中,材料在细观层次上被离散为颗粒单元集合体,相邻颗粒单元由有限单元法中的弹脆性梁单元联结。梁单元的力学性质均按韦伯(Weibull)分布随机赋值,以模拟岩石类材料力学参数的空间变异性。材料内部裂纹通过断开梁单元来模拟。通过自动生成的非均质材料模型对岩石类材料的破坏机理进行研究。岩石类非均质脆性材料在单轴压缩状态下破坏过程细观数值模拟结果显示,岩石材料宏观破坏是由于其内部细观裂纹产生、扩展、贯通的结果。通过数值模拟结果之间的对比分析,揭示出岩石试样宏观破坏模式随细观层次上韦伯分布参数的变化而不同。与实际矿柱破坏形态的对比分析表明了模型的适用性。根据数值模拟结果对岩石类非均质材料的破坏机理进行了探讨。