活性矿粉在公路表面层中的应用研究

为提高沥青路面抗高温性能、耐疲劳性能和抗水损害性能,以工业副产品为主要原料,采用活化改性技术制备的活性矿粉,应用于锡林郭勒盟高寒地区公路表面层,采用四点弯曲疲劳试验和多循环浸水马歇尔试验、冻融劈裂试验以及浸水车辙试验,分别检验活性矿粉与普通矿粉对沥青混合料性能的影响效果,试验结果表明,活性矿粉可有效改善混合料的抗高温性能、耐疲劳性能和抗水损害性能。     

Research on Pulse Radiation Characteristics of Leaf-like Ultra Wide Band Antenna

A new kind of ultra wideband antenna, which consists of a leaf-like dipole and a dielectric block, is proposed and analyzed. The dielectric block is attached in parallel with the dipole near its feed point. Thus, the near field is attracted to the side where the dielectric block is located. It leads to a focusing effect of the energy in the far zone. The finitedifference time-domain （FDTD） method combined with the perfectly matched layers （PML） technique is used in the simulation of the antenna radiation characteristics. The research shows that, with proper dielectric loading and 50 Ωfeeding line, the bandwidth of the antenna can be up to 6.5 GHz, from 3.5 GHz to 10 GHz with VSWR （voltage standing wave ratio） less than 2.5.     

漏泄同轴电缆与偶极天线的耦合范围研究

文章分析了障碍物对垂直开缝漏泄同轴电缆与偶极子天线之间耦合作用的影响,以漏泄同轴电缆为发射天线,偶极天线作为接收天线,详细分析了不同位置的障碍物对偶极天线接收电平的影响,进而确定障碍物影响耦合的范围。