松辽盆地宋芳屯油田扶杨油层孔隙结构及其影响因素

通过镜下观察,宋芳屯油田扶杨油层孔隙类型较多,以粒间孔为主。细管压力曲线上看,曲线较陡,分选差,孔隙结构特征参数总体上较差,与孔隙度、渗透率有一定的关系,大的孔隙对渗透率的贡献最大。扶杨油层的孔隙结构较复杂主要由于成岩作用影响,压实作用使孔隙空间显著缩小,胶结作用和自生粘土矿物生长使孔隙进一步缩小和复杂化,后期的溶蚀作用使孔隙空间增加。     

New basis for the constitutive modelling of aggregated soils

Natural and compacted soils are usually characterized by aggregation of particles. The mechanical behaviour of these materials depends on soil structure. The oedometric compression tests performed on aggregated samples presented here showed that these materials exhibit a yield limit depending not only on stress history and stress state but also on soil structure. Evidence is provided using the neutron tomography technique. These results revealed that soil structure modification occurs together with plastic deformations. The experimental results are used to propose a new state parameter to quantify the soil structure. Based on pore-scale experimental observations, an evolution law for this parameter is proposed as a function of associated plastic strains. Considering both soil fabric and inter-particle bonding effects, a new yield limit depending on stress state, stress history and soil structure is introduced for the aggregated soils. Accordingly, a new constitutive framework consistent with strain hardening plasticity is proposed to consider soil structure effects in the modelling of aggregated soils.     

暖切变型江淮梅雨锋结构及其形成和维持机制

对在1991年7月上旬特别稳定的梅雨形势下持续10天的特大暴雨期作了合成和典型过程研究,并进一步探讨了暖切变型江淮梅雨锋天气系统模型。它在自由大气层表现为结构竖立的相当正压切变线和一种不同于经典地转动量近似的带状准二维运动场。边界层的浅层锋生倾斜环流以及偏于切变线轴以南的Ekman抽吸与自由大气层中基本上由积云对流加热驱动的竖直环流相互依存和耦合,造成持续的大暴雨。这种系统的初生和中断后复苏的机制可能是由斜压性极弱的副热带高空东移的短波扰动在低层“湿度锋”带紧南侧触发导致的一种带状CISK。     

The upper mantle structure of the yakutian kimberlite province,eastern Russia

Deep seismic sounding in the region of the Mirnyi kimberlite field indicates that the boundary velocity of the uppermost mantle is elevated (v _b=8.6–8.8 km/sec) and extremely variable near the Mir kimberlite pipe. These velocity heterogeneities are probably associated with the kimberlite magmatism and may be useful in the identification of other kimberlite fields.     

Deep structure of the Central Alps in the light of recent seismic data

The deep seismic reflection traverses across the Central Alps (NFP 20, ECORS-CROP) contain a new set of data on the lower crust which has been interpreted in different ways. One currently fashionable model depicts the European lower crust (ELC) as gently dipping below the Adriatic crust. However, this model requires that an observed sharp termination of the ELC under the internal border of the External Massifs is due to the non-transmission of organized seismic energy through the complex upper crust. This explanation is questioned as other reflections in this and similarly complex areas are recorded, and as the same sharp termination of the ELC under the internal border of the External Massifs is observed on all seismic lines for a length of 300 km. A tectonic — metamorphic cause appears to more satisfactorily explain the obeservations, and therefore an alternative model combining surface and deep geophysical data is proposed. It consists of three mutually largely decoupled tectonic levels. (1) The shallow obducted part or lid, bounded at its base by the combined Late Miocene Jura and Lombardic basal thrusts. Estimates of shortening based on balanced sections are at least about 100 km. (2) The intermediate level between the brittle-ductile transition and the top of the subducted mantle. It contains a stack of lower crust imbrications (with a minor admixture of upper mantle) accommodated by (inducted into) the ductile middle crust. Estimates of shortening based on area balancing are again of the order of slightly more than 100 km. (3) The subducted upper mantle, for which there are no reflection data.In the Central Alps the Late Miocene phase was dextrally transpressive, producing flower structures at the shallow level (External Massifs); the stacks of lower crust imbrications at the intermediate level may be the equivalent of the External Massifs at that level. Inverted flower structures of the subducted mantle are possible, but no detailed data are available.     

杠杆点评估及设计空间抗差

本分析了杠杆点的几何含义和统计特征,从杠杆点的保差性,矩阵的摄动和参数估值可靠性的观点出发讨论了杠杆点的不利和有利的两个方面,提出了一个全面的设计空间抗差方案。     

On the physical model of earthquake precursor fields and the mechanism of precursors＇timespace distribution──origin and evidences of the strong body earthquake──generating model

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Phase transitions in the ISM a source of dissipative behaviour

By considering a simple fluid model, we investigate the role of phase transitions in the ISM on the galaxy- scale gas dynamics. Cooling and heating timescales in the ISM are typically shorter than typical galactic rotation timescales, so the individual phases in the ISM can be assumed to be in temperature equilibrium with the radiation field. Using this approximation we can construct an equation of state which depends upon the average density and mass fractions in the individual phases. Previous studies suggest that there is an equilibrium phase fraction as a function of pressure. We incorporate evolution towards this equilibrium state as a relaxation term with a time to obtain equilibrium . We derive a condition in terms of a critical Mach number when one dimensional shocks should be continuous. For small values of the relaxation time we show that the relaxation term acts like a viscosity. We show with one dimensional simulations that increasing causes shocks to become smoother. This work suggests that phase changes can strongly effect the gas dynamics of the ISM across spiral arms and bars.     

毫秒时间尺度太阳微波辐射新特征

自1990年6月北京天文台太阳射电偏振仪投入实测以来,观测到一百多个“Spike”和短时标精细结构微波幅射,其中包括一些新的微波幅射特征。本文给出了主要的四点特征:(1)窄带辐射;(2)快速偏振逆转;(3)快速频率漂移;(4)不同时标的准周期振荡。