In connection with the problem of the travel time accuracy (LTI), an improved ray tracing method based on then linear travel time interpolation but using nonlinear interpolation is developed in this paper. The method takes advantage of multiple nodes on the boundary for reducing interpolation error, thus, the travel time accuracy is increased in full fi eld while the advantages of LTI method in rapid calculation and overall optimization are retained. The comparison of numerical and experimental results shows that the nonlinear interpolation algorithm is higher accuracy than the LTI algorithm and it can be used to trace several kinds of ray paths such as direct wave, refracted wave and transmitted wave for complex media.

描述济南地磁台建台以来,周边环境随着城市化进程发生的变化,计算不同重量、距离的铁磁性物质对磁房建筑场地地磁场的影响,应用G856质子旋进磁力仪,采取梯度测量的方法,进行地磁场总强度F测量,对测量结果进行计算和初步分析,以期为其他地磁台的观测环境分析提供参考.

In this disquisition,a geomagnetism data management system based on web using B/S structure is described. In order to increase work efficiency and improve information circumstance,we transform the geomagnetism data managing mode from file to database,and present a systemic solving scheme for the reconstruct of the functions dealing with geomagnetism data,such as report、manage、apply and so on,and data transfer to internet. Meanwhile,combined with reforming of working flow,we provide technique support for the improvement of information construct and service level of our system.

发展了一种根据单台垂向记录的地震直达P波的第一个周期信号,研究地震波传播路径中介质衰减频散特性的方法.为了更有效地提高P波频散测量的分辨率和信噪比水平,减小系统误差,使用了数据重采样技术.应用改进的多重滤波方法测定P波群速度延迟.根据线性滞弹性体松弛模型反演得到了介质品质因子Qm、95%置信水平下的测量误差及相关参数.对营口台记录的辽宁岫岩震群的研究结果表明:①1999年11月9日开始出现高Qm值,高Qm值对应的地震集中在距营口台32～46 km,明显偏离Qm随震中距增加的线性规律;②5.4级地震前平均Qm值为460,5.4级地震后至2000年1月12日5.1级地震之前Qm值为391,5.1级地震之后Qm值为204.

A method for determining medium quality factor is developed on the basis of analyzing the attenuation dispersion of the arrived first period P wave. In order to enhance signal to noise ratio, improve the resolution in measurement and reduce systematic error we applied the data resampling technique. The group velocity delay of P wave was derived by using an improved multi-filtering method. Based on a linear viscoelastic relaxation model we deduced the medium quality factor Qm, and associated error with 95% confidence level. Applying the method to the seismic record of the Xiuyan M=5.4 earthquake sequences we obtained the following result: (1) High Qm started to appear from Nov. 9, 1999. The events giving the deduced high Qm value clustered in a region with their epicenter distances being between 32 and 46 km to the Yingkou station. This Qmversus distance observation obviously deviates from the normal trend of Qm linearly increasing with distance. (2) The average Qm before the 29 Dec. 1999 M=5.4 earthquake is 460, while the average Qm between the M=5.4 event and the 12 Jan. 2000 M=5.1 earthquake is 391, and the average Qm after the M=5.1 event is 204.

1 DDN业务简介 DDN是数字数据网(Digital Data Network)缩写,它是利用数字信道传输数字信号的数据传输网.采用光纤(数字微波和卫星)等数字传输通道和数字交叉复用节点组成的数字数据传输网,可以为用户提供各种速率的高质量数字专用电路和其他新业务,已满足用户多媒体通信和组建中高速计算机通信网的需要.主要作用是向用户提供永久性和半永久性连接的数字数据传输通道.DDN的主要特点为:①输速率高:在DDN网内的数字交叉连接复用设备能提供2 Mbps或N*64 kbps(≤2 M)速率的数字传输信道;②传输质量高:数字中继大量采用光纤传输系统用户之间专有固定连接,网络时延小;③协议简单:采用交叉连接技术和时分复用技术,由智能化程度较高的用户端设备来完成协议的转换,本身不受任何规程的约束,是全透明网,面向各类数据用户;④灵活连接方式:可以支持数据、语音、图像、传输等多种业务,它不仅可以和用户终端设备进行连接,也可以和用户网络连接,为用户提供灵活的组网环境;⑤电路可靠性高:采用路由迂回和备用方式,使电路安全可靠;⑥网络运行管理简便:采用网管对网络业务进行调度监控,业务的迅速生成.