Helmholtz算子逆的多方向分裂

Fourier有限差分(FFD)方法是一个重要的波场深度延拓方法，它需要用到包括Taylor展开、连分式晨开、迭代展开等一系列数学展开，将FFD方法从二维推广到三维时，需要解决二维Helmholtz算子的求逆问题。本文利用多方向分裂方法导出了二维Helmholtz算子逆的近似公式，可以应用于三维波场深度延拓问题的研究。     

检层法钻孔S波速测量中的震相问题

在岩土工程测量中，Ｓ波速度是一个重要参数，正确地识别其震相，对提高Ｓ波速度的测试精度非常重要。郭铁拴先生等发表关于“检层法鲇孔波速测量中的震相分析”一文中提出在有套管的检层Ｓ波测量中，深度大于４０ｍ时，Ｓ波震相淹没在折射波中。     

用于多频电磁波测井的圆锥螺旋式有源接收天线

对用负阻抗变换电路同圆锥螺旋天线相结合，构成的有源接收天线进行了理论分析。并给出了该有源天线稳定工作的条件和设计原理。结果表明，用该方法设计的有源接收天线具有很宽的频带、较高的灵敏度和很小的尺寸，是多频电磁波测井较为理想的接收天线。     

极谱催化波测定天然水中微量锗的研究

系统研究了Ｇｅ－ＡＲＳ－Ｈ２Ｃ２Ｏ４－Ｖ体系报道极谱催化波的影响因素，测定了Ｇｅ－ＡＲＳ－Ｈ２Ｃ２Ｏ４三元配合物的配合比为１：２：１。实验初步证明了该体系催化波为具有吸附性质的平行催化波。本法检出限为０．１４ｍｇ．ｍＬ＾－１，相对标准偏差小于９．８９％，标准回收率为９３．７０％－１０９．０％，０－５０ｍｇ．ｍＬ＾－１的锗具有良好的线性关系。     

应力波与可滑移岩石界面间的相互作用研究

研究了应力波与用节理刚度系数描述的线性滑移岩石界面间的相互作用，给出了其透、反射波幅的一般表达式。通过应力波垂直人射界面时的具体分析，反映出岩石界面的节理刚度对应力波传播的重要影响，并揭示了岩石界面对应力波的高频滤波作用。     

Barotropic local instability and severe storm process

By means of barotropic model, the characteristic and initial value problems are investigated to reveal the local two-dimensional barotropic instability of the nonuniform current to the dynamic mechanism of the formation of the Yangtze-Huaihe River severe storm in July 1991. Analytical theory and numerical experiment show that (i) the unstable developing modes are chiefly the two periods of about 44 d and 10 d, which are fundamentally consistent with that of the precipitation change of the Yangtze-Huaihe River. (ii) The growth rate of the local perturbation is dominated by the meridional wave numbern = 1–5 and zonal wave numberk = 1–12, i.e. the severe storm over the Yangtze-Huaihe River results from the interaction of the systems at different latitudes and waves of different scales, (iii) The perturbation over the Yangtze-Huaihe River possesses the property of local intensification, which slowly migrates westward over the lower and middle reaches of the Yangtze-Huaihe River. (iv) The growth rate of the instability, especially the propagation velocity of the perturbation, is sensitive to the external parameters ū and α. Project supported by the National Natural Science Foundation of China.     

Properties of wave velocity for two types of granitoids at high pressure and temperature and their geological meaning

The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure and high temperature. The laws of velocity changes for them differ with the pressure boost and temperature rise, and the velocity change of S-type is more violent than that of I-type. The “softening point” of compressional wave velocity (V μ) is also revealed during the measurement for two types of granitoids imitating the pressure and temperature at a certain depth. But the depth of “softening”, V_p after “softening” and the percentage of V_p’s drop around the “sofrening point” for two types of granitoids are obviously different. The depth of “softening” is 15 km approximately and V_p after “softening” is 5.62 km/s for S-type granitoid. But for I-type granitoid the depth of “softening” is 26 km approximately and V_p after “softening” is 6. 08 km/s. Through careful analysis of rock slices after the experiment, it was found that the “softening” of elastic-wave velocity is caused by the partial melting of granite. Combined with the results of geophysical prospecting, these results suggest that the low-velocity layers developing in the interior of Earth crust are related to thc partial melting of different types of granitoids. The formation of the low-velocity layer in the upper-middle Earth crust is closely related to the development of S-type granitoid, but that in the lower Earth crust is closely related to the development of I-type granitoid.     

Geometric form of Haiyuan fault zone in the crustal interior and dynamics implications

The deep seismic reflection data on profile HY2 are reprocessed by the method of simultaneous inversion of velocity distribution and interface position. By the travel-time inversion with the data of the diving wave Pg and fault plane reflection wave, we determine the geometric form and velocity of Haiyuan fault zone interior and surrounding rock down to 10 km depth. The measured data show that the amplitudes have strong attenuation in the range of stake number 37–39 km, suggesting the fault zone has considerable width in the crustal interior. The results of this paper indicate that to the north of the fault zone the crystalline basement interface upheaves gradually from southwest to northeast and becomes shallow gradually towards northeast, and that to the south of the fault zone, within the basin between Xihua and Nanhua mountains, the folded basement becomes shallow gradually towards southwest. The obliquity of the fault zone is about 70° above the 3 km depth, about 60° in the range of the 3–10 km depths. From the results of this paper and other various citations, we believe that Haiyuan fault zone is in steep state from the Earth’s surface to the depth of 10 km. Foundation item: Joint Seismological Science Foundation of China (201001) and State Key Basic Research Development and Programming Project (95-13-02-02). Contribution No. RCEG200308, Exploration Geophysical Center, China Earthquake Administration.