This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle se...This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons. Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion, which is much more approximate to the light source for the practical purpose. We discuss in detail the effects of the soliton＇s velocity with some parameters in the process of transmission. The results show that by choosing special parameters, one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale.展开更多
Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Wel...Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Well-balanced neuronal-microglial interactions are essential for brain functions.However,determining the role of microglia—the primary immune cells in the brain—in neuroinflammation in AD and the associated molecular basis has been challenging.Methods:Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed.The mechanism for microglial inflammation was investigated.IL6 and TNF-α were found to be significantly increased in the AD stage.Results:Our analysis revealed that microglia were extensively activated in AD cerebra,releasing sufficient amounts of cytokines to impair the neural stem cells(NSCs)function.Moreover,the ApoD-induced NLRC4 inflammasome was activated in microglia,which gave rise to the proinflammatory phenotype.Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis.These findings demonstrate the critical role of ApoD in microglial inflammasome activation,and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation.Conclusion:Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment.展开更多
在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,AP...在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,APOD)所需滤波器总电感量较大。针对以上问题,在定量分析比较PD和APOD两种调制方式谐波分布及边带谐波扩散特点的基础上,给出了两种调制方式总电感量约束方程。为保有APOD调制谐波分布集中优点的同时减小APOD总电感量需求,研究了一种基于最优三次谐波注入的改进APOD调制策略,分析了不同三次谐波注入量对APOD电压谐波分布及总电感量需求的影响,进而给出了以总电感量需求最小为目标的三次谐波最优注入量的计算方法,该方法可以实时根据当前调制度自动计算需要注入的三次谐波最优幅值,实现最优三次谐波的在线注入。最后,仿真和实验结果表明,所提策略不仅可以有效地避开高阶滤波器的谐振点,而且可有效降低主导谐波电压幅值,从而减小所需滤波器总电感量。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 60677003)
文摘This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons. Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion, which is much more approximate to the light source for the practical purpose. We discuss in detail the effects of the soliton＇s velocity with some parameters in the process of transmission. The results show that by choosing special parameters, one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale.
基金supported by the Guiding Science and Technology Development Grant in the Social Sector of Luoyang(2101083A)。
文摘Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Well-balanced neuronal-microglial interactions are essential for brain functions.However,determining the role of microglia—the primary immune cells in the brain—in neuroinflammation in AD and the associated molecular basis has been challenging.Methods:Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed.The mechanism for microglial inflammation was investigated.IL6 and TNF-α were found to be significantly increased in the AD stage.Results:Our analysis revealed that microglia were extensively activated in AD cerebra,releasing sufficient amounts of cytokines to impair the neural stem cells(NSCs)function.Moreover,the ApoD-induced NLRC4 inflammasome was activated in microglia,which gave rise to the proinflammatory phenotype.Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis.These findings demonstrate the critical role of ApoD in microglial inflammasome activation,and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation.Conclusion:Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment.
文摘在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,APOD)所需滤波器总电感量较大。针对以上问题,在定量分析比较PD和APOD两种调制方式谐波分布及边带谐波扩散特点的基础上,给出了两种调制方式总电感量约束方程。为保有APOD调制谐波分布集中优点的同时减小APOD总电感量需求,研究了一种基于最优三次谐波注入的改进APOD调制策略,分析了不同三次谐波注入量对APOD电压谐波分布及总电感量需求的影响,进而给出了以总电感量需求最小为目标的三次谐波最优注入量的计算方法,该方法可以实时根据当前调制度自动计算需要注入的三次谐波最优幅值,实现最优三次谐波的在线注入。最后,仿真和实验结果表明,所提策略不仅可以有效地避开高阶滤波器的谐振点,而且可有效降低主导谐波电压幅值,从而减小所需滤波器总电感量。
