In order to control weld penetration of carbon steel more favorable, the process of double-electrode MIG welding and image segmentation algorithm based on MSRF model were studied. The welding pool was shot by passive ...
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In order to control weld penetration of carbon steel more favorable, the process of double-electrode MIG welding and image segmentation algorithm based on MSRF model were studied. The welding pool was shot by passive visual inspection system. The principles, visual collected system and image segmentation algorithm were introduced. The captured welding pool image was segmented and detected. Finally, the detected results used by Canny differential operators and this algorithm respectively were compacted. The result indicates that the algorithm based on MSRF model can detect the edge of welding pool which includes rich molten pool information. Also this algorithm runs less computational complexity, has higher convergence speed and avoids over-segmentation phenomena than differential operators. A new image segmentation algorithm was provided for controlling weld penetration of carbon steel by Double-Electrode MIG Welding.
A 3-D finite element model of two-stage thermoelectric generator based on low-temperature thermoelectric material bismuth-telluride and medium-temperature thermoelectric material skutterudites is established. Based on...
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B4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity...
B4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4 K−1 at 1500K.
The momentum of strong backward flowing melt jet and the thermal action from transferred droplets are two dominating factors affecting the formation of humping bead in high speed gas metal arc welding （GMAW）. Approp...
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The momentum of strong backward flowing melt jet and the thermal action from transferred droplets are two dominating factors affecting the formation of humping bead in high speed gas metal arc welding （GMAW）. Appropriate describing the influ- ence of the distribution mode of droplet heat content in the weld pool is essential to understand the physical mechanism of humping bead formation. Based on the exper- imental results, four kinds of droplet heat content distribution modes are proposed and employed to calculate the transient evolution of the temperature field and weld pool during high speed GMAW process. Through making comparison of predicted and measured weld bead dimensions, a suitable and adaptive distribution mode of droplet heat content is found, i.e., droplet heat content is distributed in bottom layer of gouging region at the front of weld pool, and is averagely distributed in the whole layer at the rear of weld pool. The proposed mode is also validated by experimental observation of the weld pool images and measured by geometric dimensions of the weld bead.
WO3-based varistors doped with Y2O3 were prepared and the microstructure, nonlinear electrical properties, and dielectric properties were investigated. Breakdown voltages Eb of WO 3 doped with Y2O3 are lower than that...
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In present study LiMn2O4-xFx were prepared by the sol-gel method. X-ray diffraction (XRD) and scanning electron microscope (SEM ) were employed to detect the microstructure of the reaction products. It were found perf...
In present study LiMn2O4-xFx were prepared by the sol-gel method. X-ray diffraction (XRD) and scanning electron microscope (SEM ) were employed to detect the microstructure of the reaction products. It were found perfect crystal particles were obtained, and its' size were uniform in 1∼2 μ m. The specific capacity and cycleability were measured basing on battery program control test system. The results shown the substitution of F for O increased the specific capacity of the material at the cost of the cycleability due to more Mn3+ and less Mn4+ existed in the material. The exist of Mn3+ would reduce cycleability of cathode material due to the Jahn-Teller effect which were caused by the deformation of the crystal structure.
The operation characteristics of proton exchange membrane fuel cells with the channel width of 1mm and 2 mm under a medium-pressure are addressed, and the effect of temperature on the operation characteristic is inves...
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The operation characteristics of proton exchange membrane fuel cells with the channel width of 1mm and 2 mm under a medium-pressure are addressed, and the effect of temperature on the operation characteristic is investigated in detail. The results show that fuel cell with a 2 mm channel width can realize the long time operation in a closed-ended situation. The voltage of the 1mm width cell can drop from 0.7 V to 0.5 V in 3 min, while the 2 mm width cell can last for more than 53 min. Moreover, the temperature has a significant effect on the performance, the voltage of the 1 mm width cell can drop from 0.69 V to 0.5 V in less than 1.7 min. The resistance of the cell is increasing with the temperature, but the amplitude is smaller in high temperature.
Aluminum nitride whiskers were synthesized by nitridation of commercial aluminum powder at 1623K in a nitrogen atmosphere. The starting materials consisted of aluminum and carbon black. The carbon acted as a barrier b...
Aluminum nitride whiskers were synthesized by nitridation of commercial aluminum powder at 1623K in a nitrogen atmosphere. The starting materials consisted of aluminum and carbon black. The carbon acted as a barrier between aluminum powders during nitridation and was removed by heating in air at 923K. The whiskers were about 0.5-1μm in diameter and 10-20μm in length. The droplets at the whisker tips showed that the whiskers grew via a vapor-liquid-solid mechanism. The morphologies of the whiskers were studied by means of SEM and TEM. The formation of the whiskers depended on the processing conditions.
In the present study electronic structures of the interface between SBT and transition metal including Au, Ag, Cu, Ni, Pt were studied by employing DV-Xα method. The calculations were performed on cluster models of t...
In the present study electronic structures of the interface between SBT and transition metal including Au, Ag, Cu, Ni, Pt were studied by employing DV-Xα method. The calculations were performed on cluster models of the interface which were SrTa8O36-M2 (M=Au, Ag, Cu, Ni, Pt, and Bi). The calculations results including Fermi level, bond order, atomic charge distribution shown that there existed significant hybridization between metal d states and the O2p–Ta3d states. The Fermi levels of the metals located in the gap of SBT and metal-induced states, and the position of the Fermi levels did not change greatly due to the different transition metals. The charge of Sr and the transition metal atom transferred to oxygen atom, so that the bonding between Sr (or metal atom) and O was almost ionic bonding. The interactions between transition metal and SBT mainly came from the Coulomb interaction.
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