雷雨次声波的三维动态频谱测量研究

采用三台电容式次声接收器，在北京昌平安装次声三点阵，并测量到2000年7-8月15次强雷阵雨的次声波P-t曲线及其三维动态频谱，频谱分析结果表明：（1）雷阵雨的次声波主要来自雷次声。（2）雷次声的频谱有三大特点：其一是听到雷声越响时，雷次声振幅越强；其二是特强振幅持续时间很长；其三是周期范围时而连续、时布分布在周期较长和较短端，形成谱图上一个个空洞。据此可区别与其它次声波。（3）初步探讨了雷次声的产生机理和传播特点。     

1993年7月12日日本北海道地震次声波

１９９３年７月１２日北京时间２１点２１分１９秒在北京中关村次声接收阵上及时地发现并完整地记录了日本北海道地震所产生的当地次声波（包括地震纵波、横波、表面波所辐射的声波）和震中次声波。其中当地次声波分别有：周期为１２ｓ，振幅为０．８Ｐａ，持续３．４ｍｉｎ；及周期为１２ｓ，振幅为０．４Ｐａ，持续１ｍｉｎ和周期为３０ｓ，振幅为１．３Ｐａ，持续１２ｍｉｎ；震中次声波周期为１３７ｓ，振幅为６．９Ｐａ，持续２８ｍｉｎ。它们叠加在周期为１２ｍｉｎ、幅度为１０Ｐａ的大气异常现象的波列上。     

在He和Ne的流动余辉中POCl3的解离动力学

本文利用流动余辉技术研究了亚稳态原子Ｈｅ（２＾３ｓ）和Ｎｅ（＾３ｐ０．２）与ＰＯＣｌ３分子的传能反应，获得了激发态碎片ＰＯ（Ａ）和ＰＯ（Ｂ）的发射光谱，测定了Ｈｅ（２＾３ｓ）与ＰＯＣｌ３反应中ＰＯ（Ａ）和ＰＯ（Ｂ）的形成速率常数，其数值分别为：ＫＰＯ（Ａ）＝３．６８×１０＾－１１ｃｍ＾３·ｍｏｌｅｃｕｌｅ＾－１Ｓ＾－１和ＫＰＯ（Ｂ）＝９．４０×１０＾－１１ｃｍ＾３·ｍｏｌｅｃｕｌｅ＾－１·Ｓ＾－１     

会议消息

会议消息第七届噪声与大众健康问题国际会议１９９８年１１月２２－２７日在澳大利亚悉尼市举行．通信地址：ＮｏｉｓｅＥｆｆｅｃｔｓ’９８ＧＰＯＢ。ｘ１２８ＳｙｄｎｅｙＮＳＷ２００１Ａｕｓｔｒａｌｉａ第五届国际声和振动会议将于１９９７年１２月１５－１８日在南...     

次声波的物理性质及其应用

我们对次声波在不同介质中传播的物理性质进行整理, 结合近年来相关研究成果进行分析, 此外对产 生次声波的声源进行整理, 对其在次声监测等领域的应用进行综述, 对产生次声波的多种方法进行整理. 较全面地 刻画出次声波物理性质的真实图景, 对引导人们以客观理性的态度认识次声波很有意义     

非晶PET纤维的分子链段取向分布的研究

用对称透射法,收集在室温下不同拉伸比的非晶聚酯（ＰＥＴ）纤维之二有Ｘ射线散射（ＷＡＸＳ）强度函数Ｉ（κ,α）,采用自编ＭＰＳ９６型全谱分峰程序,将不同方位角α测得的ＷＡＸＳ强度曲线上的４个非晶重叠峰进行分解,获得分子链间原子 射引起的２个峰为：ＫＡ＝０．１４１ｎｍ＾－１,ＫＢ＝０．１７２ｎｍ＾－１;分子链内原子 射引起的２个峰为;ＫＣ＝０．３１１ｎｍ＾－１,ＫＤ＝０．５５５ｎｍ＾－１,详细分析了     

LaH2分子基态（C2V,A1）的势能函数

在ＱＣＩＳＤ水平上基于相对论紧致有效势（ＲＣＥＰ：Ｒｅｌａｔｉｖｉｓｔｉｃ Ｃｏｍｐａｃｔ Ｅｆｆｅｃｔｉｖｅ Ｐｏｔｅｎ－ｔｉａｌ）方法优化出ＬａＨ２分子的基态为Ｃ２ｖ（Ｘ＾２Ａ１）构型,其〈ＨＬａＨ－１２４４°、平衡核间距Ｒｅ＝２．１９４５Ａ和离子解能Ｄｅ＝５．５９９ｅＶ,并计算出谐振频率：ｖ１＝１２１６．５２１ｃｍ＾－１、ｖ２＝１０８７．４１７ｃｍ＾－１和ｖ３＝２１５６．９５７２ｃｍ＾－１。     

基于薄膜动圈式的次声波监测装置设计

基于薄膜动圈式声-电转换原理,利用次声波产生的空气微压波动带动薄膜上线圈受迫振动,引起线圈内磁通量的变化产生感应电动势,将声信号转换成电信号进行采集,设计便携式次声监测装置.在模拟简谐次声环境中的测量结果表明,该装置能够准确地测量出振动频率,并对其幅度进行监测.     

汤加火山喷发所产生的次声波

2022年1月15日汤加火山发生了剧烈的喷发。在火山喷发后的8 h 39 min,距离火山喷发位置10151 km的昆明次声台阵记录到很强的次声波信号。次声波波列前几个周期平均为443 s,传播速度约为321 m/s,其波形幅度与频率随时间变化与核爆炸产生的次声波形相似。采用相关检测方法估计次声信号的方位角为119°。在持续监测中,还观测到了火山喷发产生的次声信号沿反方向绕地球到达的信号和沿正方向绕地球一周后再次到达的信号。      

大地震前出现的异常次声波观测研究

研究了一种在大地震前出现的异常次声波,揭示其与地震发生的空间、时间、强度的对应关系.利用CASI-ICM-2011型次声测量传感器在一系列Ms6.0级以上大地震发生前2周以内检测到的一种频率范围0.001 Hz至0.01 Hz的次声波,其特征有:幅值范围50 Pa至200 Pa,持续时间0.5 h至4 h,传播速度10 m/s至30 m/s,震级越高信号越强.通过建立广域次声传感器网络,成功定位了芦山地震前4天出现的异常次声波,以及巴基斯担地震前12天出现的异常次声波.通过对8年时间连续监测数据的分析,研究了这类次声波的出现规律.同时,对其产生机理提出了大地起伏激发次声波的假设,进行了理论论证,并用智利地震测量信号和玉树地震测量信号证明S波可以激发出本地同振的次声波.文中所列举的数个震前异常次声信号的观测结果对于地震预测的信息获取具有参考价值.     

强地震的前兆次声波研究

利用在北京昌平安装的次声三点阵,对强地震前兆次声波进行了5年的连续观测。统计分析结果表明:强震前约10天内常能测到振幅很强的前兆次声。其三维动态频谱的特点是,振幅由弱逐渐加强,达到极值后变弱;先为长周期波(10-20分),紧跟着短周期波(5-10分),然后又出现更长的周期波,最后长短周期波一起出现。提前时间与三点阵到震中距离之间没有明显的关系,与震级之间也没有明显的关系。     

Infrasonic waves caused by the earthquake on 12 July 1993 in Japan

I.IntroductionTheinfrasonicwavesradiatedbytheseismicwaves1knownasseismicinfrasound,canspreadoutandcanbereceivedbytheinfrasoundmonitoringsystemwhichhavebeendevelopedandarebeingperfecteddaybydayI1-1o].Theseismicwavspropagateinal1directionswithintheearthbodyandradiateseveraltypesofinfrasonicwaves.Oneofthemcalledthelocalinfrasonicwaveisradiatedbyearthsurfaceattheveryinfrasoundstationwhereseismicwavesarepassingthrough;thesecondtypecalledepicentralinfrasonicwavesareradiatedbythestrongmotionoftheear…     

大气中一种低频次声波观测研究

分析大气中存在的一种低频次声波。利用宽频带次声测量传感器阵列组成的广域分布网络,对此种次声波进行了近5年不间断的检测。对所测次声信号的观察统计发现,它与自然事件密切相关。对这种信号波形、频谱、时频图及相关性进行分析进一步发现,该波通常以一组或间歇性多组形式出现,频率主要在0.001～0.02 Hz之间、幅度一般可达50～200 Pa。在2008年3月20日新疆于田地震、2008年5月12日四川汶川地震以及2009年10月29日陕甘川三省交界处的地震前,均检测到了大幅值的低频次声波。本文的分析结论对研究大气次声波的多样性及其与自然现象的关系提供了新的参考,对地震信息探测具有一定的实际意义。     

Infrasonic waves generated from the volcano eruption in Tonga

The Hunga-Tonga-Hunga-Ha'apai volcano in Tonga erupted violently on January 15, 2022. After 8 hours and 39 minutes, an infrasound array in Kunming at a distance of 10151 km away from the volcano recorded a sequence of strong infrasonic waves. The average period of the first four infrasonic waves is 443 s with propagation speed of 321 m/s. The azimuth angle of this event has been estimated by applying the progressive multi-channel correlation(PMCC) method to process the received signals. During continuous monitoring, the infrasonic waves propagating along and opposite to the direction towards the Kunming array around the earth are recorded respectively.     

The ?lugo? fireball of January 19, 1993

Summary Observational data and the theory of the interaction of meteoroids with the Earth’s atmosphere enable us to characterize the spectacular fireball which was observed to cross Northern Italy from SE to NW on January 19, 1993, ending at about 00∶33 h UT with an explosion approximately over the town of Lugo di Romagna. For estimated visual magnitudesM _v=−22⋎−25 at the peak of the light curve corresponding to values of an initial radius of (1.5⋎3) m, a meteor luminosity ranging between 3·10¹⁸ and 4·10¹⁹ erg/s is obtained, consistent with the radiant flux values obtained by the Stefan-Boltzmann law for a black-body temperature of tens of thousand degrees. The explosion of the bolide produced low-frequency (1.5⋎2) Hz) infrasonic waves which were monitored by a microseismic network of three stations near Ferrara and by regional seismic stations of the ING (Istituto Nazionale di Geofisica) at (20⋎60) km distances from the epicentre located in the stratosphere. The analysis of recovered microremnants nearby the epicentre in the form of spherules of vaporized and recondensed material, outlines the relative importance of light chemical elements typical of soft structures in small Earth-crossing bodies.     

Responses of the Ionosphere to the Great Sumatra Earthquake and Volcanic Eruption of Pinatubo

A sudden ionospheric disturbance was detected by the Doppler shift sounding equipment at Beijing, about 25 min later after the outbreak of the Sumatra earthquake on 26 December 2004. This ionospheric disturbance appeared less than lOmin after the earthquake was first recorded at Beijing seismological station by the arrival of the seismic Rayleigh wave. The analysis shows that about 18rain is the time necessary for the seismic Rayleigh wave to propagate from the epicentre to Beijing and then about 5-10min for acoustic waves to propagate from the surface of the Beijing area to the altitude of the ionosphere. Also, a report was made as another example to show the ionospheric response of Doppler shift observation at Beijing area during the Mount Pinatubo eruption of 1991. These two examples show clear evidence of the lithosphere-atmosphere-ionosphere coupling. The former case is in the frequency domain of infrasonic waves of the Earth surface oscillation due to the Rayleigh waves caused by the earthquake, while the latter is in the acoustic-gravity wave category directly excited in the atmosphere by the mass and energy eruptions of Mount Pinatubo.     

Subjective loudness and annoyance of filtered N-wave sonic booms.

The contribution of the "infrasonic" low-frequency content of sonic boom N waves to subjective loudness and annoyance has been investigated. An extended low-frequency response loudspeaker-driven simulation booth was employed, with computer-generated input test signals. For test N waves of 1 ms rise time and 150 ms duration, frequencies below 25 and 50 Hz, respectively, were cut off by digital filters simulating simple RC circuits. The filtered signal amplitude was adjusted versus the amplitude (48 Pa) of a reference unfiltered N wave (effective low-frequency cutoff approximately 0.1 Hz) until the two sounded equally loud (first experiment) or equally annoying (second experiment). The amplitude differences for equality were very slight: less than 0.6 dB at most. Surprisingly, while loss of the low frequencies slightly decreased the loudness, it slightly increased the annoyance.     

新疆实验次声台阵设计

次声测量与数据是次声各项研究的基础,而次声台阵是现代次声测量的主要形式,为此设计并建立了两个无人值守式实验次声四元台阵。描述了次声台阵的结构,对台站的仪器构成进行了说明,重点对其降噪管和通信系统进行了描述。降噪管为十字玫瑰花瓣型降噪管,给出了其降风噪性能。台站通信系统基于VPN进行架构,实现了数据的实时自动传输和FTP传输功能。实测结果表明实验台阵的噪声主要是由微气压、山背波和台阵附近的随机干扰噪声构成。台阵记录到了大量当量较小的区域地表采矿、采石微差爆破次声信号,也记录到了2013年2月15日俄罗斯陨石大爆炸事件相关的清晰的次声信号。分析结果表明,该次声台阵具有良好的性能,具有一定的推广价值。