为了提高柴油机电子控制系统(electronic control system,ECS)的可靠性及典型故障时的可用性,研究ECS热冗余设计方法与冗余系统控制策略,并以柴油机电子调速器为对象验证热冗余控制系统的控制性能。通过分析ECS的功能特点和结构组成,将...为了提高柴油机电子控制系统(electronic control system,ECS)的可靠性及典型故障时的可用性,研究ECS热冗余设计方法与冗余系统控制策略,并以柴油机电子调速器为对象验证热冗余控制系统的控制性能。通过分析ECS的功能特点和结构组成,将ECS冗余设计分为传感器冗余、ECU冗余以及执行器冗余,重点研究双ECU冗余技术和双线圈电磁铁执行器冗余切换控制方法。针对ECS双机数据实时性要求设计了基于XGATE和软件中断的双机CAN总线数据共享机制;详细定义了双机运行状态以及运行状态管理控制策略;设计双机运行与故障切换控制策略,根据麦克斯韦电磁场理论以及控制系统传递函数原理,设计了积分偏差累加项赋值以及位置环增益整定的双线圈冗余切换控制算法。基于潍柴X6170柴油机电子调速器为应用目标进行配机试验,验证双机热冗余控制系统控制性能和切换性能。结果表明,双机控制权切换过程中瞬态转速波动率2. 5%,稳定时间小于2. 5 s,切换调速性能满足柴油机二级电站中瞬态调速性能指标要求。展开更多
The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis ...The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis of instanton technique in the spin-coherent-state path-integral representation, both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained. We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys. Rev. Lett. 80 (1998) 169), but also have great influence on the intensity of the ground-state tunnel splitting. Those features clearly have no analogue in the ferromagnetic molecular magnets. We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets. The analytical results are complemented by exact diagonalization calculation.展开更多
Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnetare studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitt...Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnetare studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in theelectronic structure, the qualitative behaviors of the physical properties are the same as in the single layer case. Theconductivity spectrum shows the low-energy peak and unusual midinfrared band, the temperature-dependent resistivityis characterized by the nonlinearity metallic-like behavior in the higher temperature range and the deviation from themetallic-like behavior in the lower temperature range and the commensurate neutron scattering peak near the half-fillingis split into six incommensurate peaks in the underdoped regime, with the incommensurability increasing with the holeconcentration at lower dopings, and saturating at higher dopings.展开更多
文摘The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis of instanton technique in the spin-coherent-state path-integral representation, both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained. We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys. Rev. Lett. 80 (1998) 169), but also have great influence on the intensity of the ground-state tunnel splitting. Those features clearly have no analogue in the ferromagnetic molecular magnets. We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets. The analytical results are complemented by exact diagonalization calculation.
文摘Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnetare studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in theelectronic structure, the qualitative behaviors of the physical properties are the same as in the single layer case. Theconductivity spectrum shows the low-energy peak and unusual midinfrared band, the temperature-dependent resistivityis characterized by the nonlinearity metallic-like behavior in the higher temperature range and the deviation from themetallic-like behavior in the lower temperature range and the commensurate neutron scattering peak near the half-fillingis split into six incommensurate peaks in the underdoped regime, with the incommensurability increasing with the holeconcentration at lower dopings, and saturating at higher dopings.
