In this study, a series of tests were conducted by using aluminum-based alloy to determine the formation of grain refining structure based on the ultrasonic vibration (UV). Furthermore, the simulation test and effect ...In this study, a series of tests were conducted by using aluminum-based alloy to determine the formation of grain refining structure based on the ultrasonic vibration (UV). Furthermore, the simulation test and effect of ultrasonic output power were studied using ammonium chloride. Finally, the mechanism of grain refinement was investigated. The results show that: (1) By applying the UV to aluminum-base alloy, the grain refining rate of ingots tended to increase with the increase of the output value of UV. (2) It was confirmed that time from after the pour to the beginning of crystallization as well as cloudiness tended to decrease with increasing the ultrasonic power value of UV. Moreover, it can be seen from each cooling curve that a uniform temperature gradient existed in the melt as the power of UV increased, that made the melt strongly stirred. (3) It was also considered that the grain refining effect of ingots, which was observed from the simulation tests, resulted from nucleation action and stirring division action by applying the UV.展开更多
Growth rates, measured as shell length and body weight daily growth, were studied in the eight families of Pacific abalone, Haliotis discus hannai Ino, reared at 12, 16 and 20 ℃for 40 d respectively. The results show...Growth rates, measured as shell length and body weight daily growth, were studied in the eight families of Pacific abalone, Haliotis discus hannai Ino, reared at 12, 16 and 20 ℃for 40 d respectively. The results show that J1Rh family grew the best at 12 ℃, with growth rates of (32.88±4.66) μm/d and (5.24±1.84) mg/d. C1Jm family had the highest growth rates of (58.00±2.00) μm/d and (9.71±1.21) mg/d at 16 ℃. J1Jm family ranked the first at 20 ℃, with growth rates of (66.00±1.76) μm/d and (10.99±0.34) mg/d. RjRh family had the slowest growth rates at all three temperatures. Shell length growth rates were 18.25, 33.00 and 43.13 μm/d respec- tively, while body weight growth rates were 2.47, 2.56 and 4.75 mg/d respectively. Both temperature and family had significant effect on growth rates (P< 0.05). At 16 and 20 ℃, maternal effects on growth rates were not significant (P> 0.05), but paternal effects on growth rates were significant (P< 0.05). Results of this study indicate genetic difference among the families and importance of select- ing male breeders in the commercial hatchery.展开更多
Dielectric data for volcanic scoria and basalt on the earth at microwave frequency are extremely sparse, and also crucial for volcanic terrains imaging, and development. In consideration of their similarity to lunar r...Dielectric data for volcanic scoria and basalt on the earth at microwave frequency are extremely sparse, and also crucial for volcanic terrains imaging, and development. In consideration of their similarity to lunar regolith (soils and rocks) in chemical and mineral composition, the dielectric data is significative for passive and active microwave remote sensing on the Moon. This study provides the data about the dielectric properties of three kinds of scoria and two kinds of basalt in China. The method put forward in this paper is also applicable for measuring the dielectric properties of dry rocks and other granular ground materials with low complex dielectric constants. Firstly, the authors measured the e' and tanδ values of strip specimens prepared from the mixture of scoria or basalt powder and polythene with the resonant cavity perturbation method at 9370 MHz. Secondly, from the ε' and tanδ values of the mixture, the ε' s and tanδ s values of solid scoria and basalt were calculated using Lichtenecker's mixture formulae. Finally, the effective complex dielectric constants, ε' e and tanδ e , of scoria at different bulk densities were calculated. The results have shown that the ε' s and tanδ s values of all solid basaltic materials measured (both solid basaltic scoria or basalt) are approximately 7 and 0.05, respectively. With increasing bulk density of scoria, the ε' c and tanδ e values of scoria increase significantly.展开更多
文摘In this study, a series of tests were conducted by using aluminum-based alloy to determine the formation of grain refining structure based on the ultrasonic vibration (UV). Furthermore, the simulation test and effect of ultrasonic output power were studied using ammonium chloride. Finally, the mechanism of grain refinement was investigated. The results show that: (1) By applying the UV to aluminum-base alloy, the grain refining rate of ingots tended to increase with the increase of the output value of UV. (2) It was confirmed that time from after the pour to the beginning of crystallization as well as cloudiness tended to decrease with increasing the ultrasonic power value of UV. Moreover, it can be seen from each cooling curve that a uniform temperature gradient existed in the melt as the power of UV increased, that made the melt strongly stirred. (3) It was also considered that the grain refining effect of ingots, which was observed from the simulation tests, resulted from nucleation action and stirring division action by applying the UV.
基金supported financially by the National High-Technology R&D Plan of China under the contract Nos 2001AA621070 and 2002AA629030,the National Natural Science Foundation of China.under contract No.30371117.
文摘Growth rates, measured as shell length and body weight daily growth, were studied in the eight families of Pacific abalone, Haliotis discus hannai Ino, reared at 12, 16 and 20 ℃for 40 d respectively. The results show that J1Rh family grew the best at 12 ℃, with growth rates of (32.88±4.66) μm/d and (5.24±1.84) mg/d. C1Jm family had the highest growth rates of (58.00±2.00) μm/d and (9.71±1.21) mg/d at 16 ℃. J1Jm family ranked the first at 20 ℃, with growth rates of (66.00±1.76) μm/d and (10.99±0.34) mg/d. RjRh family had the slowest growth rates at all three temperatures. Shell length growth rates were 18.25, 33.00 and 43.13 μm/d respec- tively, while body weight growth rates were 2.47, 2.56 and 4.75 mg/d respectively. Both temperature and family had significant effect on growth rates (P< 0.05). At 16 and 20 ℃, maternal effects on growth rates were not significant (P> 0.05), but paternal effects on growth rates were significant (P< 0.05). Results of this study indicate genetic difference among the families and importance of select- ing male breeders in the commercial hatchery.
基金the National Natural Science Foundation of China(Grant No.40473036and 40373037) the project of knowledge-innovation program of the Chinese Academy of Sciences(Grant No.KZCX2-115).
文摘Dielectric data for volcanic scoria and basalt on the earth at microwave frequency are extremely sparse, and also crucial for volcanic terrains imaging, and development. In consideration of their similarity to lunar regolith (soils and rocks) in chemical and mineral composition, the dielectric data is significative for passive and active microwave remote sensing on the Moon. This study provides the data about the dielectric properties of three kinds of scoria and two kinds of basalt in China. The method put forward in this paper is also applicable for measuring the dielectric properties of dry rocks and other granular ground materials with low complex dielectric constants. Firstly, the authors measured the e' and tanδ values of strip specimens prepared from the mixture of scoria or basalt powder and polythene with the resonant cavity perturbation method at 9370 MHz. Secondly, from the ε' and tanδ values of the mixture, the ε' s and tanδ s values of solid scoria and basalt were calculated using Lichtenecker's mixture formulae. Finally, the effective complex dielectric constants, ε' e and tanδ e , of scoria at different bulk densities were calculated. The results have shown that the ε' s and tanδ s values of all solid basaltic materials measured (both solid basaltic scoria or basalt) are approximately 7 and 0.05, respectively. With increasing bulk density of scoria, the ε' c and tanδ e values of scoria increase significantly.
