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101.
可用于复杂地质体的波动方程基准面技术 总被引:7,自引:7,他引:0
提出改进的波动方程基准面方法,用于解决地表一致性问题,通过基准面的下移,可以使深部的信号增强,变多值走时为单值走时,从根本上消除了上覆层速度横向不均匀的影响,从而可以更好地解决复杂地质体成像问题。作者从原理上对上述观点给予了证明,而且给出利用波动方程基准面有限差分法做的实例--大庆油田“陆相断隐模型”。 相似文献
102.
103.
Study on the Variational Assimilation Technique for the Retrieval of Wind Fields from Doppler Radar Data 总被引:2,自引:0,他引:2
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This paper introduces a variational assimilation technique for the retrieval of wind fields from Doppler radar data. The assimilated information included both the radial velocity (RV) and the movement of radar echo. In this assimilation technique, the key is transforming the movement of radar echo to a new radar measuring variable- "apparent velocity" (AV). Thus, the information of wind is added, and the indeterminacy of recovering two-dimensional wind only by AV was overcome effectively by combining RV with AV. By means of CMA GRAPES-3Dvar and CINRAD data, some experiments were performed. The results show that the method of retrieval of wind fields is useful in obtaining the construction of the weather system. 相似文献
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105.
吴堡矿区赋存着丰富的煤炭资源,但开采技术条件较复杂,其中水文地质条件复杂是影响煤炭开采的主要不利开采技术条件。本文依据横沟井田勘探资料,较全面地分析了井田水文地质条件,并着重评价了井田矿井充水因素。认为黄河水对横沟井田煤炭开采无影响;奥灰承压水对山西组煤层开采在正常地段不会造成危害,对太原组煤层开采有很大的威胁。并提出太原组煤层能否开采利用,还需进一步作详细地质勘查研究工作。 相似文献
106.
Simulating coseismic deformation of quartz in the middle crust and fabric evolution during postseismic stress relaxation — An experimental study 总被引:3,自引:0,他引:3
Claudia A. Trepmann Bernhard Stckhert Dorothe Dorner Rasoul Hamidzadeh Moghadam Martina Küster Klaus Rller 《Tectonophysics》2007,442(1-4):83-104
Non-steady state deformation and annealing experiments on vein quartz are designed to simulate earthquake-driven episodic deformation in the middle crust. Three types of experiments were carried out using a modified Griggs-type solid medium deformation apparatus. All three start with high stress deformation at a temperature of 400 °C and a constant strain rate of 10− 4 s− 1 (type A), some are followed by annealing in the stability field of α-quartz for 14–15 h at zero nominal differential stress and temperatures of 800–1000 °C (type A + B), or by annealing for 15 h at 900 °C and at a residual stress (type A + C).The quartz samples reveal a very high strength > 2 GPa at a few percent of permanent strain. The microstructures after short-term high stress deformation (type A) record localized brittle and plastic deformation. Statisc annealing (type A + B) results in recrystallisation restricted to the highly damaged zones. The new grains aligned in strings and without crystallographic preferred orientation, indicate nucleation and growth. Annealing at non-hydrostatic conditions (type A + C) results in shear zones that also develop from deformation bands or cracks that formed during the preceding high stress deformation. In this case, however, the recrystallised zone is several grain diameters wide, the grains are elongate, and a marked crystallographic preferred orientation indicates flow by dislocation creep with dynamic recrystallisation. Quartz microstructures identical to those produced in type A + B experiments are observed in cores recovered from Long Valley Exploratory Well in the Quaternary Long Valley Caldera, California, with considerable seismic activity.The experiments demonstrate the behaviour of quartz at coseismic loading (type A) and subsequent static annealing (type A + B) or creep at decaying stress (type A + C) in the middle crust. The experimentally produced microfabrics allow to identify similar processes and conditions in exhumed rocks. 相似文献
107.
Jialin Zhou Xin Zhang Lin Zhang Fang Dong Erwin Oh 《Geomechanics and Geoengineering》2020,15(3):159-171
ABSTRACT This paper describes compressive static load tests of concrete driven piles confined by Carbon Fibre Reinforced Polymer (CFRP). The tested piles include one concrete pipe pile and one concrete rectangular pile which are all partially confined by CFRP, and other two piles with the same dimensions without CFRP application. Tests program was performed to obtain the behaviours of these composite piles. Four Static Loading Tests (SLTs) were conducted and the results shown that those two types of composite pile demonstrate less vertical displacement with the same loading of traditional concrete piles. Furthermore, the traditional methods of Load-settlement (Q-s) curves, Settlement-lg (Load) (s-lgQ) curves and Settlement-lg (Time) curves are analysed. Due to un-plunging condition, the interpretation methods of Davisson’s, DeBeers, Double-Tangent as well as Chin’s methods are demonstrated for the ultimate bearing capacity of these four piles. It is concluded that the CFRP confinement increased the ultimate bearing capacity and this composite material can be perfectly applied in geotechnical condition. 相似文献
108.
C. G. Campbell & P. M. Heptinstall 《Monthly notices of the Royal Astronomical Society》1998,301(2):558-568
A full numerical solution is found for the effect of a strongly magnetic star on its accretion disc, for the case of magnetic buoyancy diffusion. As in the previously considered case of turbulent diffusion, the disc becomes disrupted when magnetic and viscous stresses become comparable. A magnetically induced temperature elevation leads to electron scattering opacity and radiation pressure becoming significant far from the stellar surface, with consequent viscous instability and vertical disruption of the disc. This, together with the previous turbulent case, suggests that such a disruption mechanism owing to strongly magnetic accretors is generally operable. 相似文献
109.
Gavin Ramsay & Peter J. Wheatley 《Monthly notices of the Royal Astronomical Society》1998,301(1):95-100
We present low–medium resolution optical spectroscopy of the eclipsing AM Her system MN Hya (RX J0929–24). We determine the magnetic field strength at the primary accretion region of the white dwarf to be 42 MG from the spacing of cyclotron features visible during π ∼ 0.4–0.7. From spectra taken during the eclipse we find that the secondary has an M3–4 spectral type. Combined with the eclipse photometry of Sekiguchi, Nakada &38; Bassett and an estimate of the interstellar extinction we find a distance of ∼300–700 pc. We find unusual line variations at π ∼ 0.9: Hα is seen in absorption and emission. This is at the same point in the orbital phase at which a prominent absorption dip is seen in soft X-rays. 相似文献
110.
L. Burderi A. R. King & G. A. Wynn 《Monthly notices of the Royal Astronomical Society》1998,300(4):1127-1130
Lorimer et al. have recently reported that the spin-down age (∼7 × 109 yr) of the low-mass binary pulsar PSR J1012+5307 is much higher than the cooling age (3 × 108 yr) of its white dwarf companion. The proposed solutions for this discrepancy are outlined and discussed. In particular, the revised cooling age estimate proposed by Alberts et al. agrees with data from other low-mass binary pulsar systems if a transition to the 'classical' cooling regime occurs between ∼0.14 and ∼0.28 M⊙ . If this transition is excluded, PSR J1012+5307 seems to have finished its accretion phase far from the spin-up line. 相似文献