一种改进的周跳多项式拟合方法

多项式拟合探测周跳受相位观测值所含误差的影响,随着采样数的增加,其探测周跳的能力随之降低,通常将观测数据分成若干段来进行处理。这样不可避免的增加工作强度,降低工作效率。本文根据多项式拟合探测周跳的基本原理,对多项式进行改进。经实验证明,利用改进后的多项式进行拟合能够有效地弥补传统方法的不足,使周跳的探测与修复更加稳定可靠。     

四元体系Na~ ∥Cl~-,CO_3~(2-),B_4O_7~(2-)-H_2O 273K介稳相平衡研究

采用等温蒸发法研究简单四元体系Na ∥Cl-,CO32-,B4O72--H2O273K时的介稳相平衡,并测定该体系273K平衡液相中各组分的溶解度及密度,该体系的介稳相图和密度组成图显示:该四元体系在273K时的相图由3条溶解度单变量线、3个结晶区及1个共饱和点组成。体系属简单共饱型,无复盐或固溶体形成,3个结晶区分别对应单盐Na2CO3·10H2O,NaCl和Na2B4O7·10H2O。共饱点E处于Na2CO3·10H2O,NaCl及Na2B4O7·10H2O3盐共饱和,所对应的平衡液相组成为w(Na2CO3)=6.81%,w(NaCl)=21.69%,w(Na2B4O7)=0.65%,w(H2O)=70.85%。研究体系在273K下,Na2CO3·10H2O是碳酸钠盐的唯一析出形式,且硼酸钠对碳酸钠有盐析作用。     

UNB多波束数据格式解析

采用VB进行程序设计,实现了对数据文件的解析,提取出了各种不同类型的数据,介绍了数据的处理与应用.     

遥感图像线性影纹理解专家系统设计与实现

线性影纹信息是遥感图像中的一类重要信息,线性影纹信息自动提取是遥感图像智能解译的重要研究领域。笔者采用基于特征对象的专家系统技术来完成线性影纹信息的简单类别提取,设计并实现了线性影纹理解专家系统;阐明了系统结构,解译规则获取、表达,基于消息的不确定性推理机及解释机的设计;最后利用系统做了线性影纹类别提取实验,结果表明基于特征对象的专家系统用于线性影纹类别自动提取是切实可行的,并具有较高的提取精度。     

GIS支持的城市固体废弃物规划管理信息系统构建

研究了基于组件式GIS平台MapX的城市固体废弃物规划管理信息系统的设计与实现;讨论了系统框架与系统功能设计、数据库设计和系统实现的关键技术。以昆明市为例,构建了基于MapX的城市固体废弃物规划管理信息系统。该系统能够实现城市固体废弃物各类数据的采集、表达和输出,提供与城市固体废弃物管理模型无缝集成的接口,可利用地图、文字、表格等多种手段为城市固体废弃物规划管理提供辅助决策。     

GPS signal acquisition using the repeatability of successive code phase measurements

This paper introduces a new method for GPS signal acquisition, which is based on the repeatability of successive code phase measurements and the M-of-N search algorithm. The performance of the proposed method in terms of probability of signal detection is similar to that of traditional methods, except that the calculation of the probability of detection does not rely on the noise distribution or the Carrier-to-Noise ratio (C/N₀). The code phase repeatability-based method is presented along with equations for probability of detection and probability of false detection. If the distribution of the noise is known, it also provides an estimate of the C/N₀. The proposed method is illustrated for coherent and non-coherent acquisition and C/N₀ estimation.     

On some problems of seismic crustal phase

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井下记录的PP和SS震相

本文在系统分析静海台井下地震记录图的基础上,发现并解决了具有一定实际和理论意义的两个问题:其一是证明了最初误认为是干扰的“双脉冲”图形实际上均是微地震。从而指出研究静海周围地区的地震活动性应考虑微震活动问题。其二确认静海周围地区微震波形的4个主要震相是P、PP、S和SS,并对地面反射波PP和SS能够观测到的条件作了初步分析,其结果进一步说明井下地震记录较之地面记录更为“逼真”,复杂和丰富。     

Scattering of elastic waves by a fracture zone containing randomly distributed cracks

We theoretically study the scattering ofP, SV andSH waves by a zonal distribution of cracks, which simulates a fault fracture zone. An investigation is conducted how the geometrical properties of the crack distribution and the frictional characteristics of the crack surface are reflected in the attenuation and dispersion of incident waves, as well as in the amplitudes of the transmitted and reflected waves from the zone. If the crack distribution within the fault zone changes temporally during the preparation process of the expected earthquake, it will be important for earthquake prediction to monitor it, utilizing the scattering-induced wave phenomena.We consider the two-dimensional problem. Aligned cracks with the same length are assumed to be randomly distributed in a zone with a finite width, on which elastic waves are assumed to be incident. The distribution of cracks is assumed to be homogeneous and sparse. The crack surface is assumed to be stress-free, or to undergo viscous friction; the latter case simulates fluid-filled cracks. The opening displacement of the crack is assumed to be negligibly small. The idea of the mean wave formalism is employed in the analysis, and Foldy's approximation is assumed.When the crack surface is stress-free, it is commonly observed for every wave mode (P, SV andSH) that the attenuation coefficientQ ^–1 peaks aroundka1, the phase velocity is almost independent ofk in the rangeka<1 and it increases monotonically withk in the rangeka>1, wherek is the intrinsicS wavenumber anda is the half length of the crack. The effect of the friction is to shift the peak ofQ ^–1 and the corner of the phase velocity curve to the low wavenumber range. The high wavenumber asymptote ofQ ^–1 is proportional tok ^–1 independently of model parameters and the wave modes. If the seismological observation thatQ ^–1 ofS waves has a peak at around 0.5 Hz in the earth's crust is combined with our results, the upper limit of crack size within the crust is estimated about 4 km. The information regarding the transmitted and reflected waves, such as the high wavenumber limit of the amplitude of the transmitted wave etc., allows estimation of the strength of the friction.