深层碳酸盐岩关键构造-流体演变与成岩-成储——以塔中奥陶系鹰山组为例

解析系统的构造-流体体制是认识叠合盆地深层碳酸盐岩成岩-成储规律的新思路。针对塔里木盆地塔中下-中奥陶统鹰山组深层碳酸盐岩(深度、温度分别达6500m和220℃)的系统研究表明,其发育6期方解石胶结作用,准同生、表生期胶结及浅埋藏等前三期胶结总体显示与正常海水相关的成岩特征,相比之下中-深埋藏等后两期胶结具有明显的δ13C负值和有机碳输入特征,而热流体胶结物的δ18O、δ13C值均显示相对最大负值。除准同生期选择性溶蚀和表生期溶蚀外,塔中鹰山组主要存在两期埋藏溶蚀,其中第二期除溶蚀早期方解石胶结外,还主要溶蚀白云石,且普遍与烃类注入匹配。研究区关键时期,即中晚奥陶世北西向逆冲断裂、志留-泥盆纪北东向转换走滑断裂、二叠纪张裂及相关流体活动,分别影响了鹰山组碳酸盐岩的岩溶、埋藏溶蚀-胶结等成岩-成储过程。

大陆深俯冲与超高压变质研究进展

自大陆地壳中发现柯石英和金刚石以来,大陆深俯冲研究一直是固体地球科学研究的前沿和热点领域之一。大陆俯冲带超高压变质岩的发现,掀起了板块构造理论的一场革命,促进了大陆动力学研究。近三十年来,大陆深俯冲研究在大陆地壳的俯冲深度、大陆碰撞带的p-T-t演化、大陆碰撞过程中的流体体制、大陆碰撞带深部的元素活动性、同位素定年和示踪俯冲带变质作用、超高压变质岩地质测温、俯冲隧道内部板片-地幔相互作用、大陆地壳深俯冲和折返的驱动力等方面都取得了许多重要成果。这些研究成果极大丰富了大陆动力学的内涵,发展了板块构造理论,深化了对地球内部层圈运作机制的理解。本文着重选取近三十年来大陆深俯冲研究取得的经典成果和最新进展进行评述,对存在的重要科学问题和研究方向也提出了建议。

甘肃阳山金矿独居石Th-U-Pb化学年龄及其地质和成矿意义

阳山金矿是西秦岭地区新发现的超大型金矿,作者运用电子探针测定了含矿花岗斑岩脉的独居石 Y-Th-U-Pb含量,采用 ChemAge 软件计算了各测点的表面年龄,各测点表面年龄落入3个组。第一组包括9个数据,来自独居石的核心部位,表面年龄变化于297-251 Ma,等时线年龄为268±4Ma(MWSD=0.24),记录了勉略洋俯冲引发的晚古生代弧岩浆活动。第二组包括12个数据,表面年龄变化于237～207Ma,等时线年龄为220±3Ma(MWSD=0.20),属花岗斑岩侵入结晶年龄,与西秦岭碰撞型花岗岩开始大规模发育的时间一致。第三组包括7件位于独居石边缘的测点,表面年龄变化于200～179Ma,等时线年龄为190±3Ma(MSWD=0.15),属阳山金矿的成矿时间。因此,阳山金矿成矿时间与西秦岭中生代陆陆碰撞体制的大规模流体成矿事件一致。

Modeling of fluid-induced vibrations and identification of hydrodynamic forces on flow control valves

Dynamics and vibration of control valves under flow-induced vibration are analyzed. Hydrodynamic load characteristics and structural response under flow-induced vibration are mainly influenced by inertia, damping, elastic, geometric characteristics and hydraulic parameters. The purpose of this work is to investigate the dynamic behavior of control valves in the response to self-excited fluid flow. An analytical and numerical method is developed to simulate the dynamic and vibrational behavior of sliding dam valves, in response to flow excitation. In order to demonstrate the effectiveness of proposed model, the simulation results are validated with experimental ones. Finally, to achieve the optimal valve geometry, numerical results for various shapes of valves are compared. Rounded valve with the least amount of flow turbulence obtains lower fluctuations and vibration amplitude compared with the flat and steep valves. Simulation results demonstrate that with the optimal design requirements of valves, vibration amplitude can be reduced by an average to 30%.

Fluid Flow and Heat Transfer Characteristic of Outer and Inner Half Coil Jackets

The physical models of the outer and inner half coil jackets were simplified to two types of coiled ducts.The mathematic models of incompressible fluid at the condition of laminar flow and heat transfer in the two types of jackets for cooling process reactor were set up and solved by the semi-implicit method for pressure linked equa-tions consistent （SIMPLEC） algorithm based on a control volume method.The flow and temperature fields were given and the effects of Dean and Prandtl numbers on flow and heat transfer were studied.The results show that flow in the inner half coil jacket is found to exhibit transition of secondary flow pattern from two vortices to four vortices when the Dean number increases,but that in the outer half coil jacket is not found.The critical Dean num-ber is about 96.The inner half coil jacket has stronger heat transfer ability than the outer half coil jacket and this superiority is more evident with larger Prandtl number.However,as the Dean number is greater than 105,the flow resistance enhances more severely in the inner jacket than the outer jacket.For both jackets,the centers of the heated wall are the poorest for heat transfer.

Numerical simulation of steady flow past a liquid sphere immersed in simple shear flow at low and moderate Re

This work presents a numerical investigation on steady internal, external and surface flows of a liquid sphere immersed in a simple shear flow at low and intermediate Reynolds numbers. The control volume formulation is adopted to solve the governing equations of two-phase flow in a 3-D spherical coordinate system. Numerical results show that the streamlines for Re = 0 are closed Jeffery orbits on the surface of the liquid sphere, and also closed curves outside and inside the liquid sphere. However, the streamlines have intricate and non-closed structures for Re ≠ 0. The flow structure is dependent on the values of Reynolds number and interior-to-exterior viscosity ratio.

Fluid Flow Past a Circular Cylinder with Tandem Rod and Staggered Rod at Low Reynolds Number

The flow past a primary cylinder with one tandem control rod and one staggered control rod is simulated in this paper through solving the Navier-Stokes equations. Two examples are simulated to validate the model, and the results matched well with those of previous researches. The Reynolds number based on the diameter of the primary cylinder is 500. The diameter ratio between the control rod and the primary cylinder （d/D） is 0.25. It was found that the effect of the combination of one upstream tandem control rod and one staggered control rod on the hydrodynamics of the primary cylinder is a linear superposition of the effect of a corresponding single control rod, and the effect of the upstream tandem control rod is dominant at larger spacing ratios such as G/D=2. For the combination of a downstream tandem control rod and a staggered control rod, the effect of the control rods is different from that of the corresponding single control rod in the region of 0.2〈G/D〈0.5 ＆ 30°〈a〈120° and 0.9〈G/D〈1.4 ＆ 30°〈a〈50°, where the additional effect is obvious. In this case, the effect of the downstream tandem control rod is dominant at small spacing ratios （such as G/D=0.1）. At moderate spacing ratios such as G/D=0.4, the effects of the tandem control rod and the staggered control rod are comparable in both cases.

Reform and opening up in the area of circulation:a retrospect

China＇s reform and opening up in the area of circulation are an important component of the establishment of a socialist mgrket economy system. Prior to reform and opening up, this area had long been characterized by a high level of centralization, closedness and segmentation. The domestic market was isolated from the overseas market and internal trade from foreign trade, and each had its own management system and policy environment. The thirty years of reform and opening up, however, have put a new face on the institutional environment of circulation： an open and modern system of circulation has been basically established, an embryonic WTO-consistent business administration system is taking shape, and the extension Of business and trade service ixidustries has facilitated institutional innovation. The main experience of reform is the following： first, taking opening up as the leading principle and making use of opening up to promote reform; second, following an incremental path of dealing with the easier issues before the harder ones, building up while you tear down, and gradual improvement; and third, breaking through the traditional framework of commodity circulation and establishing new business systems that accommodate more service industries. The economic implication of China＇s reform experience is as follows： an export-oriented strategy must inevitably be chosen as the point of entry for reform; there is an inherent linkage between market structure and human capital in the circulation of goods and services; and expanding the circulation of non-material goods is an important basis for institutional innovation.