Advanced Materials Research Vols. 457-458

Abstract: This paper describes the new development of the breakout prediction technique based a heat transfer model. The model aims to minimize the variation in surface temperature. The breakout prediction system of slab continuous casting has been analyzed with consideration of the principles, model and thermocouples installation. The system has been designed and implemented in the steel plants.

Abstract: Secondary cooling is one of the important techniques of continuous casting. A mathematical model for heat transfer during solidification in continuous casting was established in researching on influence of the solidifying process on slab quality. The dynamic secondary cooling system has been analyzed with consideration of the principles, nozzles arrangement method and mathematical model of solidification process. The model was applied on some continuous casting machines. It indicates that the dynamic cooling model is better than conventional ones.

Abstract: In this study, Ni-P-SiC composite coatings were prepared by adding different amount of SiC particles into electroless Ni-P plating solution. The effects of SiC particles concentration in solution on depositing rate and composition of the coatings were investigated. The different SiC contents in coatings could be obtained by adjusting the amount of SiC particle concentration in electroless plating solution. Scanning electron microscopy (SEM) results indicate that SiC particles are dispersed in the composite coating and Ni-P alloy is mainly as a bond metal envelope with SiC particles. At the same time, the microhardness became increased and the wear resistance improved with the increasing of SiC content.

Abstract: Vibration is one of problems of mechanical structures, because structural resonance or fatigue will be caused by the vibration, thus it will be cause the damage of structure. In order to avoid the damage of structure, it is necessary to analyze the stiffness characteristics of the structure，which is the natural frequency and vibration mode figure, therefore unnecessary loss because of the resonance causes can be effectively avoided. By using modal analysis method which is in the structural dynamics, vibration pattern of structure system can be visually obtained from theoretical calculation and ANSYS simulation. The first 6 order natural frequencies of different working conditions have been calculated in this paper, dynamic displacement formula in external excitation have been shown when the cage move to a different location. Vibration mode figure of structure system can be drawn corresponding to the first 6 order natural frequencies, based on the finite element analysis software ANSYS, vibration image of structure system have been simulated corresponding to the first 6 order natural frequencies. The dynamic characteristics of structure system are affected when the cage to a different location. Through the cage to a different location, external excitation force have a great influence on the top of the free end, in the actual construction, the top free ends connected tie-in device stiffness should be strengthened, the system stability will be improved.

Abstract: In this work, a transparent passive DMFC was constructed to investigate the transients in open circuit voltage (OCV) and the cell temperature difference, which changed as a consequence of the methanol crossover phenomenon, including anode temperature difference (ATD), cathode temperature difference (CTD) and methanol solution temperature difference (MTD). Experiments were carried out in a passive DMFC with an active membrane area of 9 cm2, at ambient temperature and pressure. Results showed that the OCV of the passive DMFC became relatively stable as the cell temperature difference rose to a relatively stable value about 30 min later. At the middle and high current densities (>2.21 mA cm^-2), the performance increased continuously with increasing the waiting time, but became stable when the waiting time was longer than 30 min. The experimental results indicated that the performance of the passive DMFC could be more objectively characterized by collecting polarization data simultaneously when the cell temperature rises to a relatively stable value. Without the temperature measuring equipment, a waiting time about 30 min would be a good choice for collecting polarization data.

Abstract: Top-blown furnace is known to be effectively adopted in copper smelting. This paper elaborates lance control strategies in top-blown smelting process based on the real project named KUNPENG COPPER SMELTER in China. We implement lance control by using several schemes, such as auto lower, auto raise, normal raise and emergency raise; meanwhile, we propose a method of auto creep control to stabilize tip pressure of lance. Moreover, the configuration of the smelting control system based on Emerson DeltaV is introduced. The result reported clearly shows that the lance rises and falls automatically according to specific conditions, as well as the lance tip pressure is stable and creep movement is precise and responsible.

Abstract: Radial pn-junction GaAs nanowires were fabricated and investigated in detail. These nanowires were grown on GaAs (111)B substrate by metal-organic chemical vapor deposition via Au-catalyzed vapor-liquid-solid mechanism. Two types of nanowire p-n junctions were fabricated by growing a n(p)-doped GaAs shell outside a p(n) GaAs core. P-type doping was provided by diethyl zinc, while silane was introduced for n-type doping. The morphology, crystal structure and doping characteristics were investigated by FESEM, TEM and EDS. The results showed that both the two structures were of good morphology and both dopants were successfully incorporated into the nanowires.

Abstract: The essential principle of elastic recoil detection analysis (ERDA) of hydrogen content in the film and the experimental method were described briefly. The energy spectrum of the recoiled hydrogen atom can be obtained by the elastic collision of incident ion beam with hydrogen atoms in film, and the spectrum can be transferred easily into hydrogen concentration and depth profile. For illustrating the application of ERDA in hydrogen storage research, a beam of helium ion was used to recoil hydrogen in titanium hydride and deuteride film to obtain hydrogen contents and depth profiles. This technique was believed to be powerful in determining hydrogen content in hydride films.

Abstract: It has significant engineering practicability that refining the carbides as hard phase in hypereutectic high chromium cast iron. The high chromium cast iron samples during the course of solidification were treated with electric current pulse (ECP) from the temperature of 1350 °C and 1360 °C. The effects of ECP treatment of starting temperature, processing time on the shape, size, and distribution of primary carbides was investigated. The mechanism of primary carbides refined by ECP process was also analyzed preliminarily.

Abstract: Reinforced Concrete (RC) beams in the building structures are usually assumed as a ‘T’-shaped beam when the effects of adjacent slab flange are considered. However, experimental studies on residual flexural behavior of ‘T’-shaped RC beams are rarely reported. The residual flexural behavior of two RC rectangular beams and one RC ‘T’-shaped beam after exposure to ISO834 standard fire were experimentally investigated in the paper. The detailed experimental results, including the measured temperatures, flexural capacity, load-deflection curves and concrete strain are presented. The effects of flange on temperature distribution and residual flexural behavior of RC beams were analyzed. The experimental results show that: (a) the assumption of plane section is applicable for RC ‘T’-shaped beam. (b) The flexural capacity of RC rectangular beam was decreased 18.5% after exposure to fire for 2 hours, but the ultimate mid-span deflection was increased 55.1%. (c) The residual flexural capacity and the ultimate mid-span deflection of RC rectangular beam after fire was respectively increased 8.4% and 9.9% due to the effect of flange.