Distribution and identification of the low-velocity layer in the northern South China Sea

The low-velocity layer (LVL), closely related with tectonic activities and dynamic settings, has always been a hot topic in the deep crustal structure studies. The deep seismic (OBS/OBH) and onshore-offshore experiments have been extensively implemented in the northern South China Sea (SCS) since the 1990s. Six seismic profiles were finished on the northern margin of SCS by domestic and international cooperations. The features of crustal structures were revealed and five velocity-inversion layers were discovered. Among them three LVLs with 3.0—3.5 km?s^-1 velocity are located in the sedimentary structure (2.0—6.0 km in depth and 2.0—4.6 km in thickness) of the Yinggehai Basin and Pearl River Mouth Basin. They were identified by the reflective and refractive phases for their shallow depth. The other two LVLs with 5.5—6.0 km?s^-1 velocity generally existed in the middle crust (7.0—18.0 km in depth) with an about 2.5—6.0 km thickness in the transitional crustal structure of the northeastern and northwestern SCS. They were detected by the refractive phase from their overlain and underlying layers. We explored the possible tectonic formation mechanisms combining with previously reported results, which provided evidence for the formation and evolution of SCS.     

基于多元线性回归方法的地应力研究

地应力场是地质力学与岩石力学研究的基本内容之一,地应力的大小、方向及其分布规律是油气田勘探开发中地应力研究的主要内容。在研究地应力场的过程中,区域边界条件的确定是个难点也是关键部分。以任丘潜山雾迷山组三段为例,视区域边界荷载为未知数,目标井地应力为约束条件,基于多元线性回归方法确定出区域边界条件,利用Matlab求解得出区域所受边界力。研究结果表明,基于多元线性回归方法求得的地应力值与实际测量的地应力值吻合较好。     

地应力的测井计算与标定方法

随着油气勘探开发的不断深入,地下油气储层的地应力分析也越来越受到重视。在油气勘探开发的过程中,诸如油气的运移、钻井过程中井壁的稳定性、采油过程的出砂、注水开发中的井网布置与调整、储层裂缝的发育状况等均与地应力有十分密切的关系。测井资料具有数据丰富、成本低、数据连续的优点,通过优选适当的模型,可以利用测井资料计算岩石的地应力大小。在利用测井资料计算地应力的基础上,根据Kaiser实验及现场水力压裂资料对计算的水平最大、最小主应力进行标定,建立了标定后的地应力计算模型。通过实际资料的计算与检验,证明了经刻度后的地应力模型更能真实反映实际地应力大小。     

电渣重熔过程渣皮组织和成分变化与渣池的关联性

电渣重熔过程渣皮存在明显的分层现象。本文对生产过程渣皮进行取样分析，揭示不同位置渣皮分层的组织结构和成分分布。结合激冷层的生成机制，提出以激冷层成分反映渣池成分的设想。通过同一支电渣锭生产过程不同位置(高度)渣皮的激冷层成分测定，得到冶炼过程渣池成分的变化规律。     

工业规模电渣重熔过程电磁场的数值模拟

建立了考虑集肤效应的工业规模电渣重熔过程电磁场数学模型,利用FLUENT对磁场强度实部和虚部的传输方程进行求解.分析了工频下电渣重熔过程电磁场的分布特征,并研究了电流频率和电极插入深度对电磁场的影响规律.结果表明:电流频率从0.5 Hz增加到60 Hz时,电极表面的电流密度从91 378 A/m~2增大到190 746 A/m~2;增大电流频率使磁场强度分布主要集中在电极和铸锭表面区域,渣金界面的洛伦兹力方向也会发生改变;在同功率条件下,增加电极的插入深度使远离电极端部的渣池区域中焦耳热密度增大,而电极端部附近渣池的焦耳热密度减小.     

The study on the block boundary’s driving forces and tectonic stress field of China mainland and its adjacent areas using GPS data

After reviewing the inversion study on the driving forces of China mainland and its adjacent areas, the inversion computation is made by means of genetic finite element method and covering complex method based on the displacement observations of the Crustal Movement Observation Network of China. The whole procedures of inversion study, including parameter selection, computation conditions, inversion analysis and interpretation, are given out in details. Then some conclusions are drawn:(1)the main driving forces acting on China mainland are still from the collision of Indian plate with Eurasian plate;(2)the driving forces of Pacific plate and Philippine plate are significant to the eastern China;(3)the back basin of Japan sea arc is continuously extending;(4)the forces from north prevent the northern motion of China.     

电渣重熔脱硫技术研究进展

Electroslag remelting (ESR) gives a combination of liquid metal refining and solidification structure control. One of the typical aspects of liquid metal refining during ESR for the advanced steel and alloy production is desulfurization. It involves two patterns, i.e., slag–metal reaction and gas–slag reaction (gasifying desulfurization). In this paper, the advances in desulfurization practices of ESR are reviewed. The effects of processing parameters, including the initial sulfur level of consumable electrode, remelting atmosphere, deoxidation schemes of ESR, slag composition, melting rate, and electrical parameters on the desulfurization in ESR are assessed. The interrelation between desulfurization and sulfide inclusion evolution during ESR is discussed, and advancements in the production of sulfur-bearing steel at a high-sulfur level during ESR are described. The remaining challenges for future work are also proposed.     

大陆强震机理与预测研究综述

本文对 973项目“大陆强震机理与预测”研究作了综述 ,介绍了项目研究的科学背景、总体科学思路、研究内容和科学目标。项目经过 5年的研究 ,提出了中国大陆活动地块科学假说 ,并应用于描述中国大陆现今地壳运动的特征和机制 ,探索大陆强震的发生机理和预测方法 ;项目并在地震预测流动实验场研究、强地震预测研究和重要经济区地震灾害预测研究等方面取得了一系列重要进展。这些研究成果已经在地震监测和地震减灾中初步得到应用     

Active deformation of Chinese Mainland from GPS measurement and numerical simulation

Using discontinue deformation analysis(DDA) method we analyzed the characters of the crustal deformation of Chinese mainland in this study form the velocity field revealed by 308 GPS stations. The result shows that the current N-S compression rate and W-E extension rate of the south Tibetan plateau are 1.40 × 10-8/a and 1.81 × 10-8/a, and that of Tiansan block are 2.59× 10-8/a and 0.62× 10-8/a. The Altyn Tagh is a left-lateral strike slip fault with a current slip rate of 8-12 mm/a, and the clockwise rotating rate of Tarim and Gansun-Qinghai block are -8.7 and -8.1 nrad/a, respectively, with respect to the Eurasia plate. According to the boundary condition of Chinese mainland respect to the Eurasia obtained from the DDA model, a two-dimension discontinuous finite element method(DFEM) model was built. Using this model, we evaluated the relationships between the slipping of Altyn Tagh and the crustal deformation and dynamics of Chinese mainland, and found that the slip of Altyn Tagh has influence on compression of Tibetan plateau, rotating of Tarim basin and Gansun-Qinghai block, the region absorbing the energy generated by the collision of Indio Plate and Eurasia plate, the ability and method of energy transferring toward east and the deformation of both Ordos block and North-China block. Further more, the slip of Altyn-Qiliansan Tagh strongly effects the stress field in most part of north-south seismic belt. The crustal deformation and tectonic activities of Chinese mainland west is mainly caused by the block boundary stress generated by the movement of India Plate, and it also influences some area of the east mainland through slipping along Altyn-Qiliansan Tagh. In some Part of east China and south east of China, the small-scale mantle convection and the effect of denudating can not be ignored.