X100管线钢在水饱和酸性土壤中的电化学阻抗谱特征

利用电化学阻抗谱(EIS)研究X100管线钢在水饱和酸性土壤中短期的电化学腐蚀行为。结果表明,X100管线钢在鹰潭水饱和土壤中浸泡104 h后已产生点蚀。腐蚀过程的EIS谱具有两个时间常数特征,高频区为代表反应的容抗弧,低频区为代表吸附或点蚀形核期产生的感抗弧。腐蚀初期(1 h～33 h),由于水饱和土壤介质电导率较低,电极反应过程受扩散控制;腐蚀产物在电极表面积累对反应离子扩散有阻碍作用,使阻抗增大;腐蚀产物膜疏松多孔,形成局部活化区域,使阻抗减小;Cl~-对腐蚀产物膜有破坏作用且在膜内局部地区浓缩,诱发点蚀,使阻抗减小,出现感抗特征。     

硫酸盐还原菌对铜镍合金腐蚀的影响

利用电化学测试技术，在实验室条件下研究了硫酸盐还原菌(SRB)对铜镍合金腐蚀行为的影响。实验结果表明，SRB的存在使电极开路电位明显负移，极化电阻在细菌生长后期迅速降低。在含SRB的溶液中，铜镍合金表面会形成由腐蚀产物和SRB等组成的混合膜，腐蚀速度受到Cu通过混合膜向电极表面扩散速度的控制。     

利用波动分析法研究惠民凹陷沙四段和孔店组的地层剥蚀厚度

根据波动分析法原理,结合惠民凹陷地质条件,把惠民凹陷划分为4个地质波动单元,在各单元建立从单井到区域的波动方程,通过寻找不同时期的地层沉积周期波,判断沉积缺失的原因及缺失量.研究结果表明:沙四段和孔店组普遍遭受剥蚀,但地层剥蚀厚度较大的区域主要集中在凹陷边缘靠近隆起区或边界断层附近,而凸起区的剥蚀厚度较小,且孔店组的地层剥蚀厚度明显大于沙四段的,凹陷内部的剥蚀厚度较小,对其内部烃源岩的破坏作用较小,有利于已生成烃类的保存.因此,沙四段上亚段和孔二段烃源岩应成为今后油气勘探的一个重要方向.     

超空泡水下航行器定深控制研究

极高的航速使得对超空泡水下航行器的控制变得异常复杂. 为了对其深度进行有效控制, 必须对其纵平面运动特性进行研究. 本文首先建立了超空泡水下航行器的纵平面运动模型, 分析了其纵平面运动特性; 然后进行了控制算法的综合; 最后, 仿真及试验结果均验证了所设计的航行器纵平面运动控制算法的有效性. 试验结果表明该控制系统具有较高的控制精度. 本文的研究成果为进一步研究水下超空泡航行器的运动控制提供了必要的理论基础.     

Enrichment mechanisms of rare earth elements in marine hydrogenic ferromanganese crusts

A series of selective extraction experiments were conducted on marine hydrogenic ferromanganese crusts from the seamount near the Line Island to investigate the distribution of rare earth elements(REEs) and the mechanisms of combination between REEs and the hydrogenic ferromanganese crusts.The enrichment of REEs in hydrogenic ferromanganese crusts is attributed mainly to the mineral or oxide/hydroxide of the crust rather than the growth environment.The REEs are present mainly in amorphous ferric oxide/hydro...     

Exploring the deep biosphere

Over the past two decades, scientific drilling into sediments and rocks in the ocean and the continent has revealed the presence of physiologically and phylogenetically complex microbial life in the deep subsurface. Microorganisms, most of which have no cultured or known relatives in the surface biosphere, have been discovered in sediments and rock at depth as deep as 1 km below the seafloor and more than 3 km deep in the continent. The deep biosphere probably represents the most voluminous part of the glob...     

A constitutive model for granular materials considering grain breakage

A particle breakage has a significant impact on the mechanical behavior of granular materials. In this paper, we present an elasto-plastic model with two yield surfaces to which the influence of particle breakage has been introduced. The main feature of this model is to incorporate the change in the critical state line (CSL) consequent to the grain breakage induced by isotropic and deviatoric stresses during loading. For this purpose we propose a breakage function which connects the evolution of the CSL to ...     

Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping

Vincent van Gogh (1853-1890), one of the founding fathers of modern painting, is best known for his vivid colors, his vibrant painting style, and his short but highly productive career. His productivity is even higher than generally realized, as many of his known paintings cover a previous composition. This is thought to be the case in one-third of his early period paintings. Van Gogh would often reuse the canvas of an abandoned painting and paint a new or modified composition on top. These hidden paintings offer a unique and intimate insight into the genesis of his works. Yet, current museum-based imaging tools are unable to properly visualize many of these hidden images. We present the first-time use of synchrotron radiation based X-ray fluorescence mapping, applied to visualize a woman's head hidden under the work Patch of Grass by Van Gogh. We recorded decimeter-scale, X-ray fluorescence intensity maps, reflecting the distribution of specific elements in the paint layers. In doing so we succeeded in visualizing the hidden face with unprecedented detail. In particular, the distribution of Hg and Sb in the red and light tones, respectively, enabled an approximate color reconstruction of the flesh tones. This reconstruction proved to be the missing link for the comparison of the hidden face with Van Gogh's known paintings. Our approach literally opens up new vistas in the nondestructive study of hidden paint layers, which applies to the oeuvre of Van Gogh in particular and to old master paintings in general.     

Study on the Signal Control System of Urban Traffic with a Genetic Algorithm

In the paper the aim and meaning of traffic microscopic simulation is discussed first, and then three sub-models of the system are established, e. i. the model for random generation of the vehicles, the model for car-following and lane change influenced by an adjacent vehicle, and the model for control and optimization of intersection with signal. Optimization of the traffic signal timing with a genetic algorithm and a microscopic simulation is carried out. It represents a novel approach to solving optimal signal timing.     

徐家围子断陷深层不整合结构及其与天然气运移的关系

为了深入了解徐家围子断陷深层不整合结构及其与天然气运移的关系,利用地震、钻井资料对徐家围子断陷深层不整合结构和岩石物性进行了统计分析;结合已有勘探成果划分了不整合运移通道类型,对与不整合相关的天然气运移方式进行了总结.结果表明:火山岩是徐家围子断陷深层不整合的重要组成部分,火山岩半风化岩石的孔渗性远优于顶板岩石;徐家围子断陷深层不整合运移通道可以划分为2大类9亚类,火山岩作为半风化岩石时可以形成多种类型运移通道.与不整合相关的天然气运移模式可归纳为不整合直接运移、不整合与连通砂体组合运移、不整合与断裂组合运移及不整合与断裂、连通砂体组合运移4种类型,不整合与断裂组合运移是沙河子组排出烃类运移至营城组火山岩圈闭的主要输导方式.