The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional...The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional to the electronic stopping power.Our experimental data and fitting formula of yields for H+(1 MeV≤E≤4.5MeV)impacting Au are compared with the theoretical expectation.The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.展开更多
In this paper,we theoretically investigate the existence and propagation of low amplitude nonlinear ion waves in a dense plasma under the influence of a strong magnetic field.The plasma consists of ultra-relativistic ...In this paper,we theoretically investigate the existence and propagation of low amplitude nonlinear ion waves in a dense plasma under the influence of a strong magnetic field.The plasma consists of ultra-relativistic and degenerate electrons and positrons and non-degenerate cold ions.Firstly,the appearance of two distinct linear modes and their evolution is studied by deriving a dispersion equation with the aid of Fourier analysis.Secondly,the dynamics of low amplitude ion solitary structures is investigated via a Korteweg-de Vries equation derived by employing a reductive perturbation method.The effects of various plasma parameters like positron concentration,strength of magnetic field,obliqueness of field,etc.,are discussed in detail.At the end,analytical results are supplemented through numerical analysis by using typical representative parameters consistent with degenerate and ultra-relativistic magnetoplasmas of astrophysical regimes.展开更多
介绍了一种电子雷管总线电流采集方法的专利技术,使用低成本的硬件方案,实现高精度、宽范围的电流采集。应用于电子雷管的工作电流、通讯电流、充电电流、雷管总线电流负载的采集,实现电子雷管的状态监测、数据通讯、总线保护等。重点...介绍了一种电子雷管总线电流采集方法的专利技术,使用低成本的硬件方案,实现高精度、宽范围的电流采集。应用于电子雷管的工作电流、通讯电流、充电电流、雷管总线电流负载的采集,实现电子雷管的状态监测、数据通讯、总线保护等。重点论述低成本电路设计思想,实现高精度、高分辨率、宽范围的电流采集方法。电子雷管控制模块的工作电流一般为10~30 uA,通过电流载波方式向起爆控制器发送数据,通讯电流一般为0.5~2 mA,并通过总线为发火储能电容充电,充电峰值电流1~2 mA。起爆控制器通过采集总线电流,判断电子控制模块的工作状态、采集通讯数据、充电情况等。电子雷管总线电流采集方法,使用低边电阻对电流采样,通过3路低成本的运算放大器代替差分比较器,使用MCU内部集成的12 bit AD转换器代替外部16 bit AD转换器,硬件成本降低80%以上。通过将电流分段采集,既满足了小电流采样精度,又扩展电流采样范围30倍,电流采样可覆盖总线额定电流。因无需外部AD转换模块,采样效率显著提高。展开更多
文摘The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional to the electronic stopping power.Our experimental data and fitting formula of yields for H+(1 MeV≤E≤4.5MeV)impacting Au are compared with the theoretical expectation.The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.
文摘In this paper,we theoretically investigate the existence and propagation of low amplitude nonlinear ion waves in a dense plasma under the influence of a strong magnetic field.The plasma consists of ultra-relativistic and degenerate electrons and positrons and non-degenerate cold ions.Firstly,the appearance of two distinct linear modes and their evolution is studied by deriving a dispersion equation with the aid of Fourier analysis.Secondly,the dynamics of low amplitude ion solitary structures is investigated via a Korteweg-de Vries equation derived by employing a reductive perturbation method.The effects of various plasma parameters like positron concentration,strength of magnetic field,obliqueness of field,etc.,are discussed in detail.At the end,analytical results are supplemented through numerical analysis by using typical representative parameters consistent with degenerate and ultra-relativistic magnetoplasmas of astrophysical regimes.
文摘介绍了一种电子雷管总线电流采集方法的专利技术,使用低成本的硬件方案,实现高精度、宽范围的电流采集。应用于电子雷管的工作电流、通讯电流、充电电流、雷管总线电流负载的采集,实现电子雷管的状态监测、数据通讯、总线保护等。重点论述低成本电路设计思想,实现高精度、高分辨率、宽范围的电流采集方法。电子雷管控制模块的工作电流一般为10~30 uA,通过电流载波方式向起爆控制器发送数据,通讯电流一般为0.5~2 mA,并通过总线为发火储能电容充电,充电峰值电流1~2 mA。起爆控制器通过采集总线电流,判断电子控制模块的工作状态、采集通讯数据、充电情况等。电子雷管总线电流采集方法,使用低边电阻对电流采样,通过3路低成本的运算放大器代替差分比较器,使用MCU内部集成的12 bit AD转换器代替外部16 bit AD转换器,硬件成本降低80%以上。通过将电流分段采集,既满足了小电流采样精度,又扩展电流采样范围30倍,电流采样可覆盖总线额定电流。因无需外部AD转换模块,采样效率显著提高。
