Papers by Keyword: DSA

Abstract: In the event of cerebrovascular disease, simple medical treatment is very difficult to have expected effect. Interventional therapy is a new type of diagnosis and treatment in cerebrovascular technology, with advantage of less trauma, safer, more curative effect, quicker recovery, and easier to accept. Neurology department in the hospital i belonging to had performed the Seldinger technique cerebral angiography (DSA) for 68 patients with intravascular interventional therapy from January 2013 to January 2014. Through the establishment of special preoperative and postoperative nursing dedicative team, implement the system of process type intensive care good results have been achieved.

Abstract: The aim of the present study was to investigate the role of deformation temperature on the active deformation mechanisms in a 0.6C-18Mn-1.5Al (wt%) TWIP steel. The tensile testing was performed at different temperatures, ranging from ambient to 400°C at a constant strain rate of 10^-3 s^-1. The microstructure characterization was carried out using a scanning electron microscopy. The deformation temperature revealed a significant effect on the active deformation mechanisms (i.e. slip versus twinning), resulting in different microstructure evolution and mechanical properties. At the room temperature, the mechanical twinning was the dominant deformation mechanism, enhancing both the strength and ductility. Dynamic strain aging (DSA) effect was observed at different deformation temperatures, though it was more pronounced at higher temperatures. The volume fraction of deformation twins significantly reduced with an increase in the deformation temperature, deteriorating the mechanical behavior. There was a transition temperature (~300°C), above which the mechanical twinning was hardly observed in the microstructure even at fracture, resulting in low ductility and strength. The current observation can be explained through the change in the stacking fault energy with the deformation temperature.

Abstract: The Linearized Auto-Localization (LAL) algorithm estimates the position of beacon nodes in Local Positioning Systems (LPSs) which are based on the transmission of ultrasonic signals and proposed for indoor positioning of mobile robots. In this paper we propose an improved auto-localization algorithm based on weighted least squares (WLS). The improved algorithm depends on the different error estimations which caused by the different relative positions of the beacons and the measurements nodes. Simulation results show that our WLS-based Linearized Auto-Localization Algorithm can provide improved accuracy in both distance estimation and position estimation.

Abstract: In view of the low pressure tight gas reservoir in Songnan block, the comprehensive experiment of in-situ stress is carried out. Firstly, the tuffaceous breccia of Longshen 301 and 307 has been cored and the flag line is depicted. Through the viscous remanence experiment, the secondary viscous remanence component at 0°C~200°C is gradually separated, and the average direction of the two groups core flag line are obtained, which are 92.0° and 114.7°. Then to mark the flag line as the baseline, using the wave velocity anisotropy experiment to measure the acoustic wave velocity under different phase angle, the minimum wave velocity phase angle of the two groups core are achieved, which are 23° and 44° . And combined with the direction of the flag line, the direction of maximum horizontal principal stress are determined for N69o E and N70.7o E. Finally, using DSA (differential strain) experiment, the strain recovery of 9 direction under hydrostatic pressure are measured, and the three principal strain, the magnitude and direction of the principal stress are obtained through the inversion, the maximum principal stress direction of which are N70.8o E and N71.7o E. Compared the wave velocity anisotropy experiments and DSA experimental results, both close, the direction of the regional maximum horizontal in-situ stress is determined for N70.5° E ± 1.5°. According to the above research results, the basis for the engineering design of Songnan block such as oil and gas exploration, development, drilling and production is provided.

Abstract: Strain rate jump tests were performed on the Fe-Mn-Cu-C TWIP Steels to determine the strain rate sensitivity, and serrated plastic flow was observed in the stress-strain curves during tensile tests at different constant strain rates ranging from 2.5×10-4S-1 to 2.5×10-2S-1. The Fe-Mn-Cu-C TWIP Steels exhibit high work hardening rate and outstanding mechanical properties, The excellent mechanical properties are attributed to dynamic strain aging(DSA) effect, which result from the interaction between Mn(Cu)-C atom atmosphere, C-vacancy, C-C pairs and moving dislocations.

Abstract: Three-dimensional-electrode electro-Fenton is a newly electrochemical oxidation technology to treat landfill leachate. In contrast, the removal efficiencies of COD and color in DSA system are obviously higher than those in iron anode system and the organics can be degraded more thoroughly. Under the optimal operating conditions, the removal efficiencies of COD, NH3-N and color in landfill leachate by DSA system are up to 80.8% ,55.2% and 98.6％. Besides, the reaction mechanism of three-dimensional-electrode electro-Fenton is also discussed.

Abstract: The anode of DSA (SnO₂/Sb₂O₃/IrO₂) was prepared with the brush coating thermal decomposition method. The surface crystal particles of the DSA were plump, evenly distributed dense coverage and less cracks. The electro catalytic has been enhanced. Compared with the original titanium board, the useful life of electrode was extended obviously, and removal efficiency of N, N-dimethylformamide (DMF) increased to 85.4%.

Abstract: The mechanical properties of nickel superalloys are related to the spatial distribution of hardening phases, their size and composition, and on the configurations of dislocations introduced by plastic and viscoplastic straining. Heterogeneous plastic flow in relation with dynamic strain aging is examined and synthesized. Dislocations are usually faced with the alternative of shearing or bypassing the ’ phase occupying up to 60 vol.%. Depending on ’ size, several Orowan bypassing mechanisms are observed, alternatively shearing by dislocation pairs or complex configurations involving S-ISF and S-ESF. Variables such as temperature, strain rate and Schmid factor play a decisive role in determining the dislocation configurations which either percolate through the matrix or shear the ’ structure. Various dislocation strategies and microstructures are analyzed and illustrated; they are reviewed critically and summarized in a strain rate versus 1/T mechanism map.