人工源宽角地震资料中的广角效应及其对地壳速度成像的影响

The seismic wide-angle reflection/refraction method is the one of the most effective method for probing the crustal and upper mantle structure. It mainly uses the wide-angle reflection information from the boundary in the crust and the top boundary of the upper mantle to rebuild the crust and upper mantle structure. Through analyzing the reflection and transmission coefficients of various incident waves on the interface, we think relative to the pre-critical angle reflection information the post critical angle reflection information that received by wide-angle seismic data exists a time-shift effect with the offset variation, and then it must cause the error for velocity analysis and structure image. The feature of the wide-angle seismic wave field of the fourteen representative crust columns tell us that the wide-angle effects in the different representative tectonic units for the interface depth and the interval velocity in crust. We studied the features of the wide-angle seismic wave field through building the crust model and inverse its travel time by GA method to know the wide-angle influence on crustal velocity image. At last we finished the data processing of the Tunxi-Wenzhou wide-angle seismic profile. The results are as following: (1) Through building crust model, we labeled the travel time for all the phases by ray tracing method and remove wide-angle effects method, it revealed the wide-angle effect exists in the seismic data. (2) The travel time inversion by GA method can tell us that the depth by traditional ray tracing method is shallower than the result by remove wide-angle effects method, the latter can recover the crust structure model in effect. (3) We applied the two method mentioned before to the fourteen representative crust columns in China. It indicates that the removed wide-angle effect method in travel time inversion is reasonable and effective. (4) The real data processing from Tunxi-Wenzhou wide-angle seismic profile give us the basic structure through the two ways. The main influence exhibits in the difference of the interval velocity of the curst, and the wide-angle effects in shallow interface are stronger than the deep interface.

A velocity map ion-imaging study on C2H5SH and C3H7SH photodissociation at 243 nm

Photodissociation dynamics Of C2H5SH, i-C-3-H7SH and n-C3H7SH at 243.1 nm were investigated using velocity map ion-imaging method. H-atom photolysis products were detected by a (2 + 1) resonance enhanced ionization scheme. Both the angular distribution and translational energy distribution of the H-atom elimination processes were determined from the ion images of the H-atom products. The experimental results indicate that the H-atom eliminations from these molecules are mainly direct and fast dissociation processes from a repulsive potential energy state. And a more statistical dissociation process that likely occurs oil the ground state via internal conversion has also been observed. Dissociation energies of the S-H bonds are also derived from the H-atom product translational energy distributions. (C) 2002 Elsevier Science B.V. All rights reserved.

A velocity map ion-imaging study on ketene photodissociation at 208 and 213 nm: Rotational dependence of product angular anisotropy

Photodissociation dynamics of ketene following excitation at 208.59 and 213.24 nm have been investigated using the velocity map ion-imaging method. Both the angular distribution and translational energy distribution of the CO products at different rotational and vibrational states have been obtained. No significant difference in the translational energy distributions for different CO rotational state products has been observed at both excitation wavelengths. The anisotropy parameter beta is, however, noticeably different for different CO rotational state products at both excitation wavelengths. For lower rotational states of the CO product, beta is smaller than zero, while beta is larger than zero for CO at higher rotational states. The observed rotational dependence of angular anisotropy is interpreted as the dynamical influence of a peculiar conical intersection between the B-1(1) excited state and (1)A(2) state along the C-S-I coordinate.

Characterization of Air-Water Two-Phase Vertical Flow by Using Electrical Resistance Imaging

The characterization of air-water two-phase vertical flow in a 12 m flow loop with 1.5 m of vertical section is studied by using electrical resistance tomography (ERT). By applying a fast data collection to a dual-plane ERT sensor and an iterative image reconstruction algorithm, relevant information is gathered for implementation of flow characteristics, particularly for flow regime recognition. A cross-correlation method is also used to interpret the velocity distribution of the gas phase on the cross section. The paper demonstrates that ERT can now be deployed routinely for velocity measurements and this capability will increase as faster measurement systems evolve.

Measurements of Flow Patterns and Velocities of Gas -Water Two -Phase Flows Using Electrical Resistance Imaging

This paper presents a measurement of flow patterns and flow velocities of gas-water two-phase flows based on the technique of electrical resistance tomography (ERT) in a 40m horizontal flow loop. A single-plane and dual-plane ERT sensor on conductive ring technique were used to gather sufficient information for the implementation of flow characteristics particularly flow pattern recognition and air cavity velocity measurement. A fast data collection strategy was applied to the dual-plane ERT sensor and an iterative algorithm was used for image reconstruction. Results, in respect to flow patterns and velocity maps, are reported.

Multiphase technique improves mud-pulse velocity calculations

Measurement while drilling (MWD) has become a popular survey technology to monitor directional data, drilling data, formation evaluation data and safety data in the world. And closed loop drilling shows promise in recent years. Obviously, the method of tr

Detection and Characterization of Long-Pulse Low-Velocity Impact Damage in Plastic Bonded Explosives

Damage not only degrades the mechanical properties of explosives, but also influences the shock sensitivity, combustion and even detonation behavior of explosives. The study of impact damage is crucial in the vulnerability evaluation of explosives. A long-pulse low-velocity gas gun with a gas buffer was developed and used to induce impact damage in a hot pressed plastic bonded explosive. Various methods were used to detect and characterize the impact damage of the explosive. The microstructure was examined by use of polarized light microscopy. Fractal analysis of the micrographs was conducted by use of box counting method. The correlation between the fractal dimensions and microstructures was analyzed. Ultrasonic testing was conducted using a pulse through-transmission method to obtain the ultrasonic velocity and ultrasonic attenuation. Spectra analyses were carried out for recorded ultrasonic signals using fast Fourier transform. The correlations between the impact damage and ultrasonic parameters including ultrasonic velocities and attenuation coefficients were also analyzed. To quantitatively assess the impact induced explosive crystal fractures, particle size distribution analyses of explosive crystals were conducted by using a thorough etching technique, in which the explosives samples were soaked in a solution for enough time that the binder was totally removed. Impact induces a large extent of explosive crystal fractures and a large number of microcracks. The ultrasonic velocity decreases and attenuation coefficients increase with the presence of impact damage. Both ultrasonic parameters and fractal dimension can be used to quantitatively assess the impact damage of plastic bonded explosives.

DPIV and Interferometry Technique for Velocity Field and Concentration Fields Measurement in Crystal Growth

The property of crystal depends seriously on the solution concentration distribution near the growth surface of a crystal. However, the concentration distributions are affected by the diffusion and convection of the solution. In the present experiment, the two methods of optical measurement are used to obtained velocity field and concentration field of NaClO₃ solution. The convection patterns in sodium chlorate (NaClO₃) crystal growth are measured by Digital Particle image Velocimetry (DPIV) technology. The 2-dimentional velocity distributions in the solution of NaClO3 are obtained from experiments. And concentration field are obtained by a Mach-Zehnder interferometer with a phase shift servo system. Interference patterns were recorded directly by a computer via a CCD camera. The evolution of velocity field and concentration field from dissolution to crystallization are visualized clearly. The structures of velocity fields were compared with that of concentration field.

A Label-Free Multisensing Immunosensor Based on Imaging Ellipsometry

An immunosensor based on imaging ellipsometry and its potential applications was demonstrated in this paper. It has been proven a fast, reliable, and convenient method to quantify the thickness distribution of protein layers or detect protein concentration in solution. Combined with a protein chip, the immunosensor was able to detect multiple analytes simultaneously without any labeling. Preliminary results demonstrated how this immunosensor could be used to monitor several independent biospecific binding processes in real-time and in situ conditions.

Biosensor with Total Internal reflection Imaging Ellipsometry

In order to monitor multiple protein reaction processes simultaneously, a biosensor based on imaging ellipsometry operated in the total internal reflection mode is proposed. It could be realised as an automatic analysis for protein interaction processes with real-time label-free method. Its principle and methodology as well as a demonstration for its applications are presented.

Fourth order accurate compact scheme with group velocity control (GVC)

For solving complex flow field with multi-scale structure higher order accurate schemes are preferred. Among high order schemes the compact schemes have higher resolving efficiency. When the compact and upwind compact schemes are used to solve aerodynamic problems there are numerical oscillations near the shocks. The reason of oscillation production is because of non-uniform group velocity of wave packets in numerical solutions. For improvement of resolution of the shock a parameter function is introduced in compact scheme to control the group velocity. The newly developed method is simple. It has higher accuracy and less stencil of grid points.

Quantifying the Effects of Contact Duration, Loading Rate, and Approach Velocity on P-Selectin-PSGL-1 Interactions Using AFM

Kinetics and its regulation by extrinsic physical factors govern selectin-ligand interactions that mediate tethering and rolling of circulating cells on the vessel wall under hemodynamic forces. While the force regulation of off-rate for dissociation of selectin-ligand bonds has been extensively studied, much less is known about how transport impacts the on-rate for association of these bonds and their stability. We used atomic force microscopy (AFM) to quantify how the contact duration, loading rate, and approach velocity affected kinetic rates and strength of bonds of P-selectin interacting with P-selectin glycoprotein ligand I (PSGL-1). We found a saturable relationship between the contact time and the rupture force, a biphasic relationship between the adhesion probability and the retraction velocity, a piece-wise linear relationship between the rupture force and the logarithm of the loading rate, and a threshold relationship between the approach velocity and the rupture force. These results provide new insights into how physical factors regulate receptor-ligand interactions.

Scheme Construction with Numerical Flux Residual Correction (NFRC) and Group Velocity Control (GVC)

For simulating multi-scale complex flow fields like turbulent flows, the high order accurate schemes are preferred. In this paper, a scheme construction with numerical flux residual correction (NFRC) is presented. Any order accurate difference approximation can be obtained with the NFRC. To improve the resolution of the shock, the constructed schemes are modified with group velocity control (GVC) and weighted group velocity control (WGVC). The method of scheme construction is simple, and it is used to solve practical problems.

Feasibility of Protein a for the Oriented Immobilization of Immunoglobulin on Silicon Surface for a Biosensor with Imaging Ellipsometry

The feasibility of using protein A to immobilize antibody on silicon surface for a biosensor with imaging ellipsometry was presented in this study. The amount of human IgG bound with anti-IgG immobilized by the protein A on silicon surface was much more than that bound with anti-IgG immobilized by physical adsorption. The result indicated that the protein A could be used to immobilize antibody molecules in a highly oriented manner and maintain antibody molecular functional configuration on the silicon surface. High reproducibility of the amount of antibody immobilization and homogenous antibody adsorption layer on surfaces could be obtained by this immobilization method. Imaging ellipsometry has been proven to be a fast and reliable detection method and sensitive enough to detect small changes in a molecular monolayer level. The combination of imaging ellipsometry and surface modification with protein A has the potential to be further developed into an efficient immunoassay protein chip.

Optimized Group Velocity Control Scheme and DNS of Decaying Compressible Turbulence of Relative High Turbulent Mach Number

To overcome the difficulty in the DNS of compressible turbulence at high turbulent Mach number, a new difference scheme called GVC8 is developed. We have succeeded in the direct numerical simulation of decaying compressible turbulence up to turbulent Mach number 0.95. The statistical quantities thus obtained at lower turbulent Mach number agree well with those from previous authors with the same initial conditions, but they are limited to simulate at lower turbulent Mach numbers due to the so-called start-up problem. The energy spectrum and coherent structure of compressible turbulent flow are analysed. The scaling law of compressible turbulence is studied. The computed results indicate that the extended self-similarity holds in decaying compressible turbulence despite the occurrence of shocklets, and compressibility has little effects on relative scaling exponents when turbulent Mach number is not very high.