对多层阻抗渐变的吸波结构设计思想进行了分析,介绍了多层阻抗渐变思想在吸波层板和泡沫两类结构吸波材料设计上的应用。理论计算与试验验证结果均表明,采用多层阻抗渐变设计能够使吸波层板和泡沫的吸波带宽向低频拓展,同时显著提高吸...对多层阻抗渐变的吸波结构设计思想进行了分析,介绍了多层阻抗渐变思想在吸波层板和泡沫两类结构吸波材料设计上的应用。理论计算与试验验证结果均表明,采用多层阻抗渐变设计能够使吸波层板和泡沫的吸波带宽向低频拓展,同时显著提高吸波泡沫的吸收强度。具有三个阻抗渐变吸收层的4 mm厚吸波层板在5~18 GHz频段反射率小于-10 d B;具有六个阻抗渐变吸收层的22 mm厚吸波泡沫在2~18 GHz频段反射率小于-10 d B,其中在6~18 GHz频段反射率小于-20 d B,8~12 GHz频段反射率小于-30 d B。多层阻抗渐变设计是提高结构吸波材料吸波性能的有效手段。展开更多
采用原位生成氢氟酸法刻蚀Ti3AlC2制备了单片层二维过渡金属碳化物(MXene),用扫描电子显微镜(SEM)、透射电子显微镜(TEM)及原子力显微镜(AFM)等表征了MXene的微观形貌.结果表明,所制备的MXene材料具有大片、单层及低缺陷等特点.通过抽滤...采用原位生成氢氟酸法刻蚀Ti3AlC2制备了单片层二维过渡金属碳化物(MXene),用扫描电子显微镜(SEM)、透射电子显微镜(TEM)及原子力显微镜(AFM)等表征了MXene的微观形貌.结果表明,所制备的MXene材料具有大片、单层及低缺陷等特点.通过抽滤MXene分散液制备的MXene膜材料具有导电性高(3280 S/cm)及韧性优异等特点.MXene膜的屏蔽性能测试结果表明,8μm厚的MXene膜屏蔽效能为60.6d B,SSE/t值则高达19531.1 d B·cm^2·g^-1.推测MXene膜的屏蔽机理是一种以吸收为主的电磁干扰屏蔽机制.展开更多
针对实时操作系统的开销导致应用程序可执行性降低的问题,提出了基于FPGA的硬件实时操作系统设计方案,并实现了μC/OS-II任务管理模块的硬件化。通过设计基于片内寄存器的TCB及基于组合电路的任务调度器,充分发挥了多任务潜在的并行性...针对实时操作系统的开销导致应用程序可执行性降低的问题,提出了基于FPGA的硬件实时操作系统设计方案,并实现了μC/OS-II任务管理模块的硬件化。通过设计基于片内寄存器的TCB及基于组合电路的任务调度器,充分发挥了多任务潜在的并行性。整个设计采用VHDL硬件描述语言,通过ISE8.2软件进行时序仿真验证,并使用Xilinx公司的Virtex-II Pro FPGA板实现。展开更多
A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the batt...A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.展开更多
In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charg...In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charge and discharge experiments were carried out to check feasibility and superiority of the new method. The results indicated that with the discharge pulse added the charger can charge quickly, the battery voltage and temperature can be properly controlled to prevent the battery being destroyed, and the capacity of the NiMH battery is greater than that of the battery without the discharge pulse added.展开更多
文摘对多层阻抗渐变的吸波结构设计思想进行了分析,介绍了多层阻抗渐变思想在吸波层板和泡沫两类结构吸波材料设计上的应用。理论计算与试验验证结果均表明,采用多层阻抗渐变设计能够使吸波层板和泡沫的吸波带宽向低频拓展,同时显著提高吸波泡沫的吸收强度。具有三个阻抗渐变吸收层的4 mm厚吸波层板在5~18 GHz频段反射率小于-10 d B;具有六个阻抗渐变吸收层的22 mm厚吸波泡沫在2~18 GHz频段反射率小于-10 d B,其中在6~18 GHz频段反射率小于-20 d B,8~12 GHz频段反射率小于-30 d B。多层阻抗渐变设计是提高结构吸波材料吸波性能的有效手段。
文摘采用原位生成氢氟酸法刻蚀Ti3AlC2制备了单片层二维过渡金属碳化物(MXene),用扫描电子显微镜(SEM)、透射电子显微镜(TEM)及原子力显微镜(AFM)等表征了MXene的微观形貌.结果表明,所制备的MXene材料具有大片、单层及低缺陷等特点.通过抽滤MXene分散液制备的MXene膜材料具有导电性高(3280 S/cm)及韧性优异等特点.MXene膜的屏蔽性能测试结果表明,8μm厚的MXene膜屏蔽效能为60.6d B,SSE/t值则高达19531.1 d B·cm^2·g^-1.推测MXene膜的屏蔽机理是一种以吸收为主的电磁干扰屏蔽机制.
文摘针对实时操作系统的开销导致应用程序可执行性降低的问题,提出了基于FPGA的硬件实时操作系统设计方案,并实现了μC/OS-II任务管理模块的硬件化。通过设计基于片内寄存器的TCB及基于组合电路的任务调度器,充分发挥了多任务潜在的并行性。整个设计采用VHDL硬件描述语言,通过ISE8.2软件进行时序仿真验证,并使用Xilinx公司的Virtex-II Pro FPGA板实现。
文摘A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.
文摘In order to design a new type of quick charger for NiMH battery, the new method of pulse charge discharge was adopted after studying the charge process and analyzing the NiMH battery charge characteristics. The charge and discharge experiments were carried out to check feasibility and superiority of the new method. The results indicated that with the discharge pulse added the charger can charge quickly, the battery voltage and temperature can be properly controlled to prevent the battery being destroyed, and the capacity of the NiMH battery is greater than that of the battery without the discharge pulse added.
