摘要
为研究超宽带雷达波在煤体中的传输衰减特性,通过NS-187矿用射频信号衰减系统,测试中心频率为400 MHz时的超宽带雷达波在厚度分别为25,45,65,85 cm的褐煤、长焰煤和贫瘦煤中的传输衰减信号。分析其信号中正负峰值的变化规律,得出超宽带雷达波的衰减特点。结果表明:随煤体厚度的增加,超宽带雷达波的信号衰减呈递增趋势。在相同煤体厚度下,褐煤变质程度最低,超宽带雷达波衰减程度最大,长焰煤次之,贫瘦煤变质程度最高,超宽带雷达波衰减程度最小。即超宽带雷达波在穿过不同变质程度的煤体时,其衰减程度与煤体厚度成正比。煤厚相同时,煤样的变质程度与超宽带雷达波的传输衰减呈反比。此外当煤体厚度大于60 cm时,在长焰煤与贫瘦煤的幅值频率关系图中,测试中心频率的左侧出现局部峰值,即该频率并非最佳探测频率,在低频范围内存在多个适宜的探测频率。以上结论对于超宽带雷达在煤体中的传输衰减特性以及井下生命探测具有一定指导意义。
To study the transmission attenuation characteristics of ultra-wideband radar waves in coal,the propagation signal of ultra-wideband radar waves at a center frequency of 400 MHz in lignite,long flame coal,and lean coal was tested through the NS-187 mine radio frequency signal attenuation system.Each coal was set to 25,45,65,and 85 cm thickness in the experiment;the changing rules were analyzed of the transmission attenuation signal’s positive and negative peak values in those three types of coals and obtained the attenuation features of the ultra-wideband radar waves.The results showed that with the increase of coal thickness,the transmission attenuation tends to increase.For the same coal thickness,ultra-wideband radar waves had the largest attenuation among the lignite with the lowest degree of metamorphism,followed by long flame coal.The metamorphic degree of lean coal was the highest,and the attenuation of ultra-wideband radar wave was the smallest.It proves that ultra-wideband radar waves’attenuation degree is proportional to coal thickness when it passes through coal with a different metamorphic degree.The same coal thickness triggers that the degree of coal sample metamorphism is inversely proportional to ultra-wideband radar waves’transmission attenuation.Besides,when the coal thickness is greater than 60 cm,a local peak appears on the left side of the test center frequency in the amplitude-frequency relationship graph of long flame coal and lean coal.Therefore,the test’s center frequency is not the best detection frequency,and there are multiple suitable detection frequencies in the low-frequency range.The conclusions above have specific guiding significance for the transmission attenuation characteristics of ultra-wideband radar in coal and underground life detection.
作者
郑学召
孙梓峪
王宝元
郭军
徐承宇
ZHENG Xuezhao;SUN Ziyu;WANG Baoyuan;GUO Jun;XU Chengyu(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Xi’an Research Center of National Mine Rescue,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《西安科技大学学报》
CAS
北大核心
2021年第5期765-771,共7页
Journal of Xi’an University of Science and Technology
基金
国家重点研发计划重点专项(2018YFC0808201)
国家自然科学基金项目(52004209,52174197)
陕西省教育厅专项科学研究计划(17JK0495)。
关键词
超宽带雷达波
煤变质程度
煤体厚度
传输衰减
正负峰值
ultra-wideband radar wave
coal metamorphic degree
coal thickness
transmission attenuation
positive and negative peaks
