A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass. Neutrinos are one of the most abundant particles in the universe. Because they have very litt...A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass. Neutrinos are one of the most abundant particles in the universe. Because they have very little interaction with matter, however, they are incredibly difficult to detect. We present a study of the physics of neutrinos using the Dirac lagrangian. Based on Lorentz invariance we introduce the notion of Majorana spinor. Then we derive the mass terms for both Dirac and Majorana neutrinos. We further discuss the general framework of the See-Saw mechanism considering a simplification of the problem.展开更多
Based on impulse and vibration machining theories,a mathematical model of cutting force for the electroplated diamond ultrasonic wire saw was established using superposition principle.The differences between the cutti...Based on impulse and vibration machining theories,a mathematical model of cutting force for the electroplated diamond ultrasonic wire saw was established using superposition principle.The differences between the cutting forces with and without ultrasonic effect were analyzed theoretically and experimentally.The results indicate that the cutting force of diamond wire increases along with the spindle speed decrease and the lateral pressure increase.The force in ultrasonic vibration cutting is about 20% to 30% less than that in conventional cutting.Also,the cutting trajectory of single diamond grit in sawing process is simulated,and the reason that the ultrasonic vibration can reduce the cutting force is explained further.展开更多
采用Er镶嵌靶,以射频(RF)反应磁控溅射法,在蓝宝石衬底上制备出了c轴取向的Er 0.11 Al 0.89 N z压电薄膜。运用正交设计实验优化后,Er 0.11 Al 0.89 N z薄膜的膜厚、表面粗糙度分别为1.20μm和1.0 nm,光学介电常数从4.19增大到4.29。Er ...采用Er镶嵌靶,以射频(RF)反应磁控溅射法,在蓝宝石衬底上制备出了c轴取向的Er 0.11 Al 0.89 N z压电薄膜。运用正交设计实验优化后,Er 0.11 Al 0.89 N z薄膜的膜厚、表面粗糙度分别为1.20μm和1.0 nm,光学介电常数从4.19增大到4.29。Er 0.11 Al 0.89 N z/蓝宝石基声表面波(SAW)谐振器的中心频率和品质因数Q值相较于纯AlN降低,有效机电耦合系数比AlN z/蓝宝石基SAW谐振器提高了20%,达到1.80%。研究结果表明,Er掺杂AlN后晶格常数比值c/a基本保持不变,但晶体中离子键成分的上升使晶体结构软化,从而导致器件频率下降,有效机电耦合系数增加。展开更多
文摘A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass. Neutrinos are one of the most abundant particles in the universe. Because they have very little interaction with matter, however, they are incredibly difficult to detect. We present a study of the physics of neutrinos using the Dirac lagrangian. Based on Lorentz invariance we introduce the notion of Majorana spinor. Then we derive the mass terms for both Dirac and Majorana neutrinos. We further discuss the general framework of the See-Saw mechanism considering a simplification of the problem.
基金Sponsored by Liaoning Innovation Team Fundation(2008T164)
文摘Based on impulse and vibration machining theories,a mathematical model of cutting force for the electroplated diamond ultrasonic wire saw was established using superposition principle.The differences between the cutting forces with and without ultrasonic effect were analyzed theoretically and experimentally.The results indicate that the cutting force of diamond wire increases along with the spindle speed decrease and the lateral pressure increase.The force in ultrasonic vibration cutting is about 20% to 30% less than that in conventional cutting.Also,the cutting trajectory of single diamond grit in sawing process is simulated,and the reason that the ultrasonic vibration can reduce the cutting force is explained further.
文摘采用Er镶嵌靶,以射频(RF)反应磁控溅射法,在蓝宝石衬底上制备出了c轴取向的Er 0.11 Al 0.89 N z压电薄膜。运用正交设计实验优化后,Er 0.11 Al 0.89 N z薄膜的膜厚、表面粗糙度分别为1.20μm和1.0 nm,光学介电常数从4.19增大到4.29。Er 0.11 Al 0.89 N z/蓝宝石基声表面波(SAW)谐振器的中心频率和品质因数Q值相较于纯AlN降低,有效机电耦合系数比AlN z/蓝宝石基SAW谐振器提高了20%,达到1.80%。研究结果表明,Er掺杂AlN后晶格常数比值c/a基本保持不变,但晶体中离子键成分的上升使晶体结构软化,从而导致器件频率下降,有效机电耦合系数增加。
