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1.
通过对辽东半岛大清河海岸平原的地貌考察和人工钻孔取样,对研究区内7个钻孔不同层位的113个样品进行了混浊水导电率测定;根据钻孔剖面海陆相沉积环境变化与导电率曲线特征值,推断出大清河海岸平原全新世时期海陆变化规律。结果表明:g1和g2的导电率曲线有2个明显的峰值,显示研究区发生了一次完整的海侵过程,且海水到达接近g3孔位置之处;另外,靠近陆侧的g3孔在海拔2.1 m处出现一小峰值,推测由于海水到达此处使得导电率变大,由此进一步得出研究区海侵时海平面(即平均高潮线)达到的最大高度为海拔接近2.1 m处,比现今海平面低1.0 m左右,说明全新世高海面之后,研究区表现为构造隆升。 相似文献
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顺序扫描 ICP-AES法测定高纯石墨灰分中14种杂质金属元素的方法研究 总被引：1，自引：0，他引：1
本文研究了快速测定石墨灰分中14种杂质元素Al,Ca,Cd,Co,Cr,Cu,Fe,Mg,Mn,Mo,Ni,Ti,V,Zn的分析方法,以满足提纯石墨研究工作对快速了解石墨提纯效果的要求.依据测定样品中各元素的含量情况,实验选择14种元素的分析线.运用ICP-AES谱线轮廓图功能,消除常量元素产生的基体背景干扰.运用干扰系数法进行测定结果校正,并对ICP-AES测定灰分中14种元素的检出线、精密度、准确度进行了测定.结果显示,本方法分析石墨灰分中杂质元素能够满足提纯石墨研究工作的要求. 相似文献
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研究膨胀石墨对模拟海水中重油的吸附热力学行为.结果表明:在293～308 K,含油量为2.172～18.11 mg·dm-3实验浓度范围内,膨胀石墨对模拟海水中重油的吸附是放热过程,吸附等温线符合Freundlich和Langmuir方程.根据热力学函数关系计算出膨胀石墨对模拟海水中重油的标准吸附焓变为-39.49 kJ·mol-1,标准吉布斯自由能变为-22.40～-23.50 kJ·mol-1,说明吸附过程可自发进行. 相似文献
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环境中的黑碳及其全球生物地球化学循环 总被引：20，自引：0，他引：20
黑碳是生物物质或化石燃料燃烧产生的难熔物质的连续统一体,从焦化植物残体、木炭到烟炱,以及石墨态黑碳,组成了黑碳的3种主要类型。它们的理化性质变化很大,焦化植物残体和木炭主要在低温下形成;烟炱是高温气态物质浓缩形成;而石墨态黑碳可能是岩石成因的。黑碳的分解主要是光化学分解和微生物降解。黑碳在全球碳循环中占有重要的位置。每年燃烧可产生50～270Tg黑碳,其中约10％来源于化石燃料燃烧。细小的黑碳在大气中被搬运到远离燃烧地的土壤或海洋中沉积下来,在沉积物有机碳中占有很大的比例。从地质历史时期看,它对于大气圈中CO2、O2的含量演化有重要影响。本文将黑碳的分析测量方法归纳为5类：显微镜法、光学法、热氧化法、化学方法和分子标志物法。同时指出当今黑碳研究中需要一种标准参考物,黑碳的测量应进一步细化到分子水平,并加强不同类型黑碳的全球生物地球化学循环过程研究。 相似文献
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海洋沉积物和悬浮物样品基体组成十分复杂,而待测元素在样品中的含量也相差甚远,这给分析工作带来了一定的困难.石墨炉原子吸收法虽然具有灵敏度高,取样量少等优点,但存在着严重基体干扰[1-2].因此很多作者不得不采用费时的分离手段或标准加入法进行测定.本文应用自制简易石墨平台和基体改进技术以及峰面积测量相结合,直接测定了海洋沉积物和悬浮物中的镉、铅、铜.方法有效地消除了普遍石墨炉原子吸收测定法分析镉、铅时所遇到的基体干扰,使标准加入法曲线与标准工作曲线的斜率比接近1.0.方法简便快速,稳定可靠。 相似文献
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用电感耦合等离子体原子发射光谱仪 (ICP AES)和石墨炉原子吸收光谱仪 (GAAS)分别测定河蚬样品中镉和铬的含量 ,以比较不同测试方法对这两种重金属测定的影响。结果表明 :2种测试法对生物样品中镉和铬含量的测定结果都有显著的影响 ,同一样品中镉和铬含量的ICP AES测定值均显著高于其相应的GAAS测定值。相比ICP AES法 ,GAAS法对河蚬样品中镉和铬含量的测定更为准确。不同方法测定的镉和铬含量的差异程度分别为 1 8.8%和1 36.4 %。本研究显示 :不同测试法对铬含量测定结果的影响比对镉含量测定结果的影响更大。 相似文献
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A new experimental protocol is explored to characterize electrical properties of hydrocarbon-bearing mudrocks at nano/micro scales. Two current flow regimes of peak force - tunneling atomic force microscopy (PF-TUNA) have been used: (1) the vertical out-of-plane current regime with hundred micrometer diameter top electrodes obtains homogenized conductivity quantitatively, (2) the horizontal in-plane current regime was shown powerful to visualize the conductive paths (related to connectivity and tortuosity) for heterogeneous and anisotropic shales. Results show that the approach works well with one to two layers of adsorbed water (25–55% relative humidity) under low frequency (0.5–20 Hz) for shale rocks. Current maps with sub-nanometer resolution emphasize the dominant role of hydrated ions associated with the hydrophilic clay minerals in driving the dielectric response of shales, while conductivity of pyrite and kerogen cannot be neglected for mature organic-rich shale conductive network. The acquired I-V curves at microscale provide a reliable mean to evaluate homogenized conductivity of such multiscale multi-component heterogeneous material under controlled environmental conditions. The procedure discussed herein serves as a complement for fine grained rocks and minerals of ionic-electronic hybrid conductive mechanism under partially water saturation. These results can be used to develop accurate electrical models, specifically for shale rocks with heterogeneous and sophisticated microstructure. The methodology can be also extended to other micro- or meso-porous geomaterials such as cementitious and bituminous nanoporous media. 相似文献
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雪热传导系数是海冰质量平衡过程中的重要物理参数,决定了穿透海冰的热传导通量。北冰洋海冰质量平衡浮标观测获得多年冰上冬季温度链剖面可以明显地区分冰雪界面。本文考虑到冰雪界面处温度随时间变化,再根据冰雪界面热传导通量连续假定,提出了新的雪热传导系数计算方法。受不同环境因素影响,多年冰上各个浮标的雪热传导系数在0.23~0.41 W/（m·K）之间,均值为（0.32±0.08） W/（m·K）。北冰洋多年冰上冬季穿过海冰的热传导通量最大发生在11月至翌年3月,约14~16 W/m2。结冰季节,来自海冰自身降温的热量对穿过海冰向大气传输的热量贡献逐月减少,从9月100%减小到12月的35%,翌年的1月至3月稳定在10%左右。夏季,短波辐射通能量通过热传导自上而下加热海冰,海冰上层温度高于下层,热量传播方向与冬季反向,往海冰内部传递。直到9月短波辐射完全消失,气温下降,热量再次转变为自下往上传递。从冰底热传导来看,夏季出现海冰向冰水界面传递热量现象。由于雪较好的绝热性,冰上覆雪极大地削弱了海冰上层热传导通量,从而减缓了秋冬季节的结冰速度。尽管受雪厚影响,多年冰上层热传导通量与气温依旧具有很好的线性关系,气温每降低1℃,热传导通量增加约0.59 W/m2。 相似文献
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The electronic structures and effective masses of the N mono-doped and Al-N, Ga-N, In-N codoped ZnO system have been calculated by a first-principle method, and comparisons among different doping cases are made. According to the results, the impurity states in the codoping cases are more delocalised compared to the N mono-doping case, which means a better conductive behaviour can be obtained by codoping. Besides, compared to the Al-N and Ga-N codoping cases, the hole effective mass of In-N codoped system is much smaller, indicating the p-type conductivity can be more enhanced by In-N codoping. 相似文献
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Stable backfill materials for the heat sensitive structures of buried power cables, hot water pipes, and gas pipelines are suggested to have low permeability and high heat transfer characteristics. The hydraulic and thermal conductivities of backfill materials or clay liners are important parameters in proper design and construction of geotechnical structures involved with heat transfers. In this study, to investigate the optimal natural backfill or liner materials, thermal and hydraulic conductivities of kaolin–silica mixtures examined based on the results from laboratory tests under different consolidation conditions. From the experiment results, the thermal conductivity increases while hydraulic conductivity decreases with increasing density during consolidation process. As a result, back-fill materials with high kaolin content under low consolidation stress were desirable materials for burial of heat sensitive structures. 相似文献
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我国东海陆架地区新生代地层的热导率 总被引：10，自引：0，他引：10
对东海陆架区的浅表层柱状岩芯样品和多口钻井岩心样品的热导率数据按岩性、深度、年龄和孔隙度进行了统计分析。发现泥岩、粉砂岩和砂岩的热导率有所不同。在3000m以上，泥岩的热导率大于砂岩的热导率；而在3000m以下砂岩的热导率则大于泥岩的热导率。粉砂岩的热导率基本介于泥岩和砂岩之间。岩石的热导率和岩石样品所处的深度密切相关，随着深度的增大热导率数值增大。岩石的年龄影响岩石的热导率。在同等深度的情况下，年龄越老，热导率数值越高，但埋深浅的老地层热导率会小于埋深大的新地层的热导率。孔隙度和含水对岩石样品的热导率有很大的影响，岩石会因孔隙中含水而使热导率有非常大的变化。本文给出了饱和水热导率和干样热导率之差和孔隙度的回归方程。 相似文献
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The design and use of a marine heat probe with capability for measuring thermal conductivity insitu with high accuracy, and providing digital acoustic transmission of data to the ship, is described. The instrument employs the violin bow strength member and parallel sensor string configuration suggested by C. R. B. Lister. Several hundred measurements have been made in the deep ocean on multipenetration or pogostick profiles using a 3 m probe and in deep inlets of western Canada using a 7 m probe. The insitu thermal conductivity technique using a calibrated heat pulse has been studied in detail through laboratory calibration of the probe in materials of known conductivity, through numerical models, and through comparison of insitu measurements with needle probe measurements on sediment cores taken from the same sites. The insitu technique permits a conductivity accuracy of better than ±5% with a recording time of 7 minutes following 7 minutes in the bottom to establish the geothermal gradient. The pulse heating is also more energy efficient than the conventional continuous heating technique.Contribution from the Earth Physics Branch No. 807. 相似文献
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The smear zone, which develops during the placement of the prefabricated vertical drain (PVD) in the ground using a steel mandrel, is a significant factor that influences the performance of PVDs. The determination of the width and hydraulic conductivity of smear zone is an important consideration in designing ground improvement by preloading with PVDs. Thus, the extent and hydraulic conductivity of the PVD smear zone have received significant attention; however, there is still uncertainty and the topic remains discrepant among investigators. There is limited or no smear zone hydraulic conductivity data that is directly produced by laboratory or field tests. In this study, a laboratory smear zone model experiment that was developed as a performance test for determining the extent of the smear zone and measuring directly its hydraulic conductivity was used. Based on the findings obtained from two different materials (Craney Island dredgings and Hydrite R kaolinite soil), it is indicated that the disturbed zone is made up of two areas, namely smear zone and transition zone, and that the hydraulic conductivity in these areas is lower than the undisturbed soil. The ratio of the hydraulic conductivity of the smear and transition zones to that of the undisturbed soil was found to vary between 0.32 and 0.50 and between 0.57 and 0.82, respectively in different soils. The diameter of the smear zone was found to be 2.3–3.3 times higher than the equivalent diameter of the mandrel depending on the soil. The diameter of the transition zone extended 5.2–7.3 times the equivalent diameter of mandrel again depending on the soil. These directly measured values, in general, are supportive of the published values based on indirect means and the test device can be used to study the impact of mandrels of different size and shape and other factors by minor modification. 相似文献
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Characterization of the hydraulic property of a specific geomaterial is of fundamental importance in engineering design and application. This paper reports an experimental investigation to the hydraulic conductivity of a typical marine sand, i.e., calcareous sand, which becomes increasingly popular as sea-filling material for land reclamation or construction of artificial islands. A series of permeability tests have been performed using the calcareous sand collected from Nansha islands in South China Sea. Using the home-made permeability test apparatus (so-called velocity-controlled pressure-differential acquisition flow apparatus), the relationship between flow velocity and hydraulic gradient was obtained and the hydraulic conductivity of calcareous sand was then determined accordingly. The effects of important parameters, including particle shape and particle size distribution on the hydraulic conductivity of calcareous sand, were assessed. To investigate the effect of particle size distribution on the hydraulic conductivity of calcareous sand, two often-used parameters, i.e., nonuniformity coefficient and curvature coefficient were considered in this study. To quantitatively evaluate the irregularity of soil particle, a particle-shape parameter was introduced and it was able to consider sphericity and circularity of highly irregular particle. Two materials, namely, Fujian quartz sand and glass beads consisting of particles of characteristic shape, were also used in the permeability tests, and they were used to compare with calcareous sand. Through the comparison, the effect of particle shape of calcareous sand on its hydraulic conductivity was examined based on the newly introduced particle shape parameter. The test results indicate that the particle size distribution has a significant influence on the hydraulic conductivity of calcareous sand. The quite irregular particle shape is able to reduce the hydraulic conductivity of the calcareous sand. A comparative study of hydraulic conductivity between the theoretical prediction and experimental measurement was performed, and it is concluded that an improvement of theoretical model for prediction of the hydraulic conductivity of the porous media consisting of particles with highly irregular shapes, such as the calcareous sand, is still required. 相似文献
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Dhananjai Pandey Martin Sinha Lucy MacGregor Satish Singh 《Marine Geophysical Researches》2008,29(3):185-193
The effects of the ocean coast on magnetotelluric (MT) data have been studied and results are described in this article. MT
soundings from various sites along coastal plains of Kachchh were acquired where volcanic rocks overlie Mesozoic sediments
having potential resource prospects. The region of our study lies in the proximity of Gulf of Kachchh and Arabian Sea. This
article describes the effects the presence of a conductive body on the acquired MT data. With the help of synthetic MT modelling
and induction arrows we demonstrate the influence of shallow conductive body on the MT data. The modelling results when compared
to the field observations show that much of the high frequencies are unaffected by the coast, however low frequencies of the
data do seem to be distorted by onshore–offshore resistivity contrasts. The least affect on high frequencies can be attributed
to very shallow water depth as well as to the fact that the onshore–offshore resistivity contrasts are not large enough to
influence the high frequency data badly. The results presented here report for the first time the effect of the coast on the
analysis on MT data from Kachchh. Due to several academic as well as industrial onshore–offshore MT experiments presently
being carried out to explore its hydrocarbon potential, our results have an important bearing on designing and acquisition
of future MT surveys in this region. 相似文献
20.
利用直接电位法,采用标准加入的方式测定了不同浓度和温度条件下,LiPF6水溶液中的F-浓度,同时考察了碱处理对LiPF6水解的影响,并采用电导率测定结果进行了验证.实验表明,LiPF6能够在水中稳定存在,且几乎不受碱度和温度的影响. 相似文献