Session 1:板块活动     

Jiu Jimmy JIAO  XIN Luo 《《地质学报》英文版》2019,93(Z2):5-6

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Robust smooth magneto tell uric transfer functions   总被引：3，自引：0，他引：3  

Jimmy C. Larsen    Randall L. Mackie    Adele Manzella    Adolfo Fiordelisi  Shirley Rieven 《Geophysical Journal International》1996,124(3):801-819

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Vibration tests and analysis of a model arch dam     

Jimmy P. Balsara  C. Dean Norman 《地震工程与结构动力学》1975,4(2):163-177

Vibration tests were conducted on a 1/24-scale model of the North Fork Dam, a double-curvature arch dam, to determine natural frequencies, mode shapes and hydrodynamic pressures. The mode shapes and natural frequencies were determined from tests using two vibrators mounted on the crest of the dam. Hydrodynamic pressures at the dam/reservoir interface were determined from tests in which the vibrator was attached to the downstream foundation of the dam. The hydrodynamic pressures calculated using Westergaard's theory and a theory for arch dams developed by Perumalswami and Kar accurately predicted the measured pressure at frequencies below the first mode frequency of the dam. The differences in the two theories were insignificant. The Structural Analysis Program (SAP), a linear three-dimensional (3-D) finite element code, was used to compute mode shapes and frequencies for the dam with its base fixed and with a foundation. Numerical solution schemes used in the finite element analysis consisted of a Ritz analysis and a subspace iteration method. Calculations were conducted for both full and empty reservoir conditions. The accuracy of the Ritz analysis improved considerably as more nodes in flexible regions of the dam were loaded. However, the lowest eigenvalues were computed using the subspace iteration method. For the full reservoir, the natural frequencies decreased by 20-30 per cent when the foundation was included in the finite element model. The difference was less when the reservoir was empty. The calculations using the subspace iteration scheme and including the foundation agreed closely with experimental mode shapes and corresponding natural frequencies.  相似文献   

Parameters of warm molecular clouds from methyl acetylene observations     

A. V. Alakoz  S. V. Kalenskii  V. G. Promislov  L. E. B. Johansson  A. Winnberg 《Astronomy Reports》2002,46(7):551-566

The results of a survey of 63 Galactic star-forming regions in the 6_K–5_K and 5 _K –4_K methyl acetylene lines at 102.5 and 85.5 GHz are presented. Fourty-three sources were detected at 102.5 GHz, and twenty-five at 85.5 GHz. Emission was detected toward molecular clouds with kinetic temperatures of 20–60 K (so-called “warm clouds”). The CH₃CCH abundances in these clouds are about several ×10^?9. Five sources (NGC 2264, G30.8-0.1, G34.26+0.15, DR 21(OH), S140) were mapped using the maximum-entropy method. The sizes of the mapped clouds fall in the range 0.1–1.7 pc, and the clouds have virial masses of 90–6200 M_⊙ and densities between 6×10⁴ and 6×10⁵ cm^?3. The CH₃CCH sources coincide spatially with the CO and CS sources. Chemical-evolution simulations show that the typical methyl acetylene abundances in the observed clouds correspond to ages of ≈6×10⁴ years.  相似文献   

Effects of galvanic distortions on magnetotelluric data: Interpretation and its correction using deep electrical data   总被引：1，自引：0，他引：1  

Jimmy Stephen  S. G. Gokarn  C. Manoj  S. B. Singh 《Journal of Earth System Science》2003,112(1):27-36

The non-inductive galvanic disturbances due to surficial bodies, lying smaller than high frequency skin depth, cause serious interpretational errors in magnetotelluric data. These frequency independent distortions result in a quasi-static shift between the apparent resistivity curves known as static shift. Two-dimensional modelling studies, for the effects of surficial bodies on magnetotelluric interpretation, show that the transverse electric (TE) mode apparent resistivity curves are hardly affected compared to the transverse magnetic (TM) mode curves, facilitating the correction by using a curve shifting method to match low frequency asymptotes. But in the case of field data the problem is rather complicated because of the random distribution of geometry and conductivity of near surface inhomogeneities. Here we present the use of deep resistivity sounding (DRS) data to constrain MT static shift. Direct current sensitivity studies show that the behaviour of MT static shift can be estimated using DC resistivity measurements close to the MT sounding station to appreciable depths. The distorted data set is corrected using the MT response for DRS model and further subject to joint inversion with DRS data. Joint inversion leads to better estimation of MT parameters compared to the separate inversion of data sets.  相似文献   

An example of landslide-inflicted damage to tunnel in the 2004 Mid-Niigata Prefecture earthquake     

Kazuo Konagai  Muneyoshi Numada  Athanasios Zafeirakos  Jörgen Johansson  Amir Sadr  Toshihiko Katagiri 《Landslides》2005,2(2):159-163

A large number of landslides induced by the 2004 Mid Niigata Prefecture earthquake resulted in the closure of 233 segments of national and prefectural routes in Higashiyama mountain district, and 61 localities were completely isolated. Since railway and road facilities follow closely the motion of soils, damage to these facilities has to be discussed in terms of soil deformations that they experienced. The example of Kizawa tunnel shows that even relatively small soil deformations can be large enough to cause serious cracking of tunnel lining.  相似文献   

First results from the plasma composition spectrometer PROMICS-3 in the Interball project     

I. Sandahl  S. Barabash  H. Borg  E. Yu. Budnik  E. M. Dubinin  U. Eklund  H. Johansson  H. Koskinen  K. Lundin  R. Lundin  A. Mostrom  R. Pellinen  N. F. Pissarenko  T. Pulkkinen  P. Toivanen  A. V. Zakharov 《Annales Geophysicae》1997,15(5):542-552

PROMICS-3 is a plasma experiment flown in the Russian project Interball. It performs three-dimensional (3D) measurements of ions in the energy range 4 eV–70 keV with mass separation and of electrons in the energy range 12 eV–35 keV. The Interball project consists of two main satellites, the Tail Probe and the Auroral Probe, each with one subsatellite. The Interball Tail Probe was launched on 3 August 1995, into a 65° inclination orbit with apogee at about 30 R_E. Both main satellites carry identical PROMICS-3 instruments and thus direct comparisons of the particle distributions will be possible once the Auroral Probe is launched. Furthermore, PROMICS-3-Tail is the first instrument measuring the 3D ion distribution function in the magnetospheric boundary layers at high latitudes. In this paper we describe the PROMICS-3 instrument and show initial results from the Tail probe, measurements of the mag-netosheath, plasma sheet, and ring current plasmas.  相似文献   

Elastic wave propagation in a radially anisotropic medium     

A. Boström  M. Johansson  T. Svedberg 《Geophysical Journal International》1994,118(2):401-410

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Simulated groundwater interaction with rivers and springs in the Heihe river basin   总被引：2，自引：0，他引：2  

Li‐Tang Hu  Chong‐Xi Chen  Jiu Jimmy Jiao  Zhong‐Jing Wang 《水文研究》2007,21(20):2794-2806

Surface water and groundwater in the Heihe river basin of China are interconnected and the pattern of water resources exploitation has a direct effect on the interaction of groundwater and surface water, especially on a downstream oasis. A three‐dimensional groundwater flow simulation model with eight model layers was established to simulate the regional groundwater flow in the multilayered aquifer system and the interaction among the rivers, springs, and groundwater. The model was calibrated not only with historical water levels but also with the investigated baseflow and spring flux. The simulation results of the numerical model match reasonably well with the observed groundwater levels, baseflow to rivers, and spring flux. The numerical simulation also demonstrates that the hydraulic connection between the river and the aquifers has transferred from the coupling to decoupling at some reaches. It is suggested that there is a vital need to reduce groundwater withdrawal and to rationalize the use of both groundwater and surface water in order to maintain sustainable development in the study area. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Alkalinity and total carbonate in Dead Sea brines - some comments on a recent paper by Sass and Ben-Yaakov     

David Dyrssen  Olof Johansson  Margareta Wedborg 《Marine Chemistry》1978,6(3):275-279

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