We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) for N-level atomic system interacting with a coherent field in the presence of Kerr (linear and non-linea...We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) for N-level atomic system interacting with a coherent field in the presence of Kerr (linear and non-linear medium) and Stark effects. It is observed that the Stark and Kerr effects play a prominent role during the time evolution of the quantum system. The evolving quantum Fisher information (QFI) is noted as time grows under the non-linear Kerr medium contrary to the QE for higher dimensional systems. The effect of non-linear Kerr medium is greater on the QE as we increase the value of Kerr parameter. However, QFI and QE maintain their periodic nature under atomic motion. On the other hand, linear Kerr medium has no prominent effects on the dynamics of N-level atomic system. Furthermore, it has been observed that QFI and QE decay soon under the influence of Stark effect. In short, the N-level atomic system is found prone to the change of the Kerr medium and Stark effect for higher dimensional systems.展开更多
In this paper,the authors propose a new space vector pulse width modulation(SVPWM)algorithm based on non-orthogonal coordinates for N-level inverters.First,it is pointed out that classicalαβcoordinates-based SVPWM h...In this paper,the authors propose a new space vector pulse width modulation(SVPWM)algorithm based on non-orthogonal coordinates for N-level inverters.First,it is pointed out that classicalαβcoordinates-based SVPWM has many shortcomings because of improper coordinate choice.Then,a non-orthogonal coordinates-based SVPWM is proposed to solve these problems.The proposed algorithm can easily identify which sector the reference space vector falls in and conduct simple operations to find the duty cycle of each vector.Finally,it is verified that the proposed SVPWM is actually a pulse−width modulation(PWM)technology based on line voltages.展开更多
文摘We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) for N-level atomic system interacting with a coherent field in the presence of Kerr (linear and non-linear medium) and Stark effects. It is observed that the Stark and Kerr effects play a prominent role during the time evolution of the quantum system. The evolving quantum Fisher information (QFI) is noted as time grows under the non-linear Kerr medium contrary to the QE for higher dimensional systems. The effect of non-linear Kerr medium is greater on the QE as we increase the value of Kerr parameter. However, QFI and QE maintain their periodic nature under atomic motion. On the other hand, linear Kerr medium has no prominent effects on the dynamics of N-level atomic system. Furthermore, it has been observed that QFI and QE decay soon under the influence of Stark effect. In short, the N-level atomic system is found prone to the change of the Kerr medium and Stark effect for higher dimensional systems.
文摘In this paper,the authors propose a new space vector pulse width modulation(SVPWM)algorithm based on non-orthogonal coordinates for N-level inverters.First,it is pointed out that classicalαβcoordinates-based SVPWM has many shortcomings because of improper coordinate choice.Then,a non-orthogonal coordinates-based SVPWM is proposed to solve these problems.The proposed algorithm can easily identify which sector the reference space vector falls in and conduct simple operations to find the duty cycle of each vector.Finally,it is verified that the proposed SVPWM is actually a pulse−width modulation(PWM)technology based on line voltages.
文摘长身高原鳅(Triplophysa tenuis)对维持木扎提河的水生态系统物质和能量流动具有重要作用。文章基于脂肪酸生物标记法和碳、氮稳定同位素(δ^(13)C、δ^(15)N)技术研究了长身高原鳅的食性和营养生态位特征。结果显示,其肌肉中共检测出22种脂肪酸,其中有8种饱和脂肪酸、6种单不饱和脂肪酸、8种多不饱和脂肪酸;由特征脂肪酸组成情况推测,长身高原鳅对浮游动物、硅藻、陆地植物或喜摄食硅藻的鱼虾均有摄食,表现为杂食性。长身高原鳅的δ^(13)C和δ^(15)N分别介于-27.09‰~-20.98‰和5.71‰~8.45‰,营养级介于2.68~3.48。雌雄样本间的δ^(13)C、δ^(15)N和营养级均不存在显著性差异(P>0.05);雄性样本核心生态位(Standard ellipse area,SEAc)和总生态位(Total area of convex hull,TA)均高于雌性。δ^(13)C与体长间表现为极显著正相关性(P<0.01),δ^(15)N和营养级与体长间不具有显著相关性。70~80 mm体长组与90 mm以上体长组SEAc面积不存在重叠且在聚类分析中被分为不同组。综上,长身高原鳅的食性为杂食性且食物组成随体长变化而不同,作为营养级偏高的捕食者,长身高原鳅能延长食物链长度,增加食物网复杂性,有利于维持水域生态系统的稳定性。
