Long-Term Geophysical Observations and Analysis of the World's Deepest Borehole

Objective In order to reduce the interfering noise from the earth surface, scientists have carried out multi-geophysical borehole observations and the related study. This study aims at improving signal-to-noise ratio obtained from the observation data to obtain zero noise data, which will be of great help to improve geophysical studies. Insights from this study will be significant for the earthquake disaster reduction, resource exploration and environmental protection.

Application of 3D stereoscopic visualization technology in casting aspect

3D stereoscopic visualization technology is coming into more and more common use in the field of entertainment,and this technology is also beginning to cut a striking figure in casting industry and scientific research.The history,fundamental principle,and devices of 3D stereoscopic visualization technology are reviewed in this paper.The authors’research achievements on the 3D stereoscopic visualization technology in the modeling and simulation of the casting process are presented.This technology can be used for the observation of complex 3D solid models of castings and the simulated results of solidification processes such as temperature,fluid flow,displacement,stress strain and microstructure,as well as the predicted defects such as shrinkage/porosity,cracks,and deformation.It can also be used for other areas relating to 3D models,such as assembling of dies,cores,etc.Several cases are given to compare the illustration of simulated results by traditional images and red-blue 3D stereoscopic images.The spatial shape is observed better by the new method.The prospect of3D stereoscopic visualization in the casting aspect is discussed as well.The need for aided-viewing devices is still the most prominent problem of 3D stereoscopic visualization technology.However,3D stereoscopic visualization represents the tendency of visualization technology in the future;and as the problem is solved in the years ahead,great breakthroughs will certainly be made for its application in casting design and modeling and simulation of the casting processes.

Numerical simulation of ground motion amplification in Modong area, Lushan

The April 20,2013,Ms 7.0 Lushan Earthquake was a major earthquake that followed the Ms 8.0 Wenchuan Earthquake on May 12,2008.Frequent earthquakes have caused heavy casualties and property loss in Western Sichuan.Earthquake disasters are often closely related to the amplification effect of ground motion.Studying the ground motion characteristics of near-surface geological structures helps to understand the distribution of potential earthquake disasters.In this study,we investigated ground motion amplification in the downtown area of Lushan using numerical simulation and aftershock data from the Lushan Earthquake.Using the Lushan earthquake aftershock data from nine seismic stations distributed in the area,the amplification effect of the sites was determined using the"reference site spectral ratio"method.The results show that the frequency of the ground motion amplification in the area was in the range 5–10 Hz,and the corresponding amplification peak was from 3 to 14.Among the study sites,the amplification(14 times)at L07 was the most prominent.To study further the amplification characteristics,shear-wave velocity models for the structures under these sites were established using passive-source Rayleigh surfacewave exploration.One-dimensional(1 D)and two-dimensional(2 D)seismic amplification effects were simulated using horizontally propagating shear-wave modeling.Except Site L07,the 1 D simulation results of each site well reflected the variation feature of the seismic amplification on the frequency band below the observed peak frequency,although the overall simulated amplification peaks were smaller than the observed results.The 2 D simulation of the remarkable amplification phenomenon at L07 was in better agreement with the observation result than was the 1 D simulation,indicating that the seismic amplification in the Modong area is influenced by lateral variation of the Quaternary sediments.