九江-瑞昌地震的精确定位及其发震构造初探

联合采用双差法和主事件法,对2005年11月26日发生在江西省九江县与瑞昌市交界的5.7级地震序列进行了重新定位,并在此基础上讨论了5.7级主震的震源机制解和可能的发震构造。结果显示:精定位后震源位置的估算误差在EW方向上平均为0.31km,NS方向上平均为0.40km,竖直方向上平均为0.48km,故而得到了更加精细的空间分布图像。此次地震序列在NNW-NW向呈现优势分布,震源深度主要集中在8～14km,又以10～12km最具优势。主震的震源位置大致为北纬29.69°,东经115.74°,震源深度约10.8km。结合地震序列优势分布、主震震源机制解和震区NE向、NW向断裂发育的构造背景,初步推测本次地震序列的主震可能是由瑞昌盆地内的一条NW向隐伏断层活动引发的,发震断层的性质有待于进一步研究。     

毫秒脉冲星计时观测的研究进展

对毫秒脉冲星时间测量的理论、方法和技术研究的进展进行了阐述。根据近年来取得的观测研究结果,毫秒脉冲星计时测量误差～2×10－7秒,毫秒脉冲星自转周期稳定性足以和现代原子钟相媲美：其相对频率不稳定度达到1×10－14（1年≤γ≤5．2年）,并可望更高。近年来,脉冲星计时观测系统的接收灵敏度获得很大改进,计时观测的数据采集、处理技术、脉冲到达时间分析模型研究等都有长足发展。通过综合脉冲星时间算法得到的脉冲星时间尺度将比现代原子时具有更高的长期稳定度。叙述了脉冲星的物理特性及有关计时观测系统的技术成果,如观测频率和带宽的选择,消色散和接收系统灵敏度等问题。最后对毫秒脉冲星时间测量的误差源进行了讨论,并对脉冲星时间尺度的应用前景做了展望。     

从桂西地区金砷汞锑元素的区域分布探讨金的物质来源

文章分析对比了桂西地区Ａｕ、Ａｓ、Ｈｇ、Ｓｂ元素的时空区域分布,并经与岩石样对比,发现上古生界以碳酸盐岩为主的地层为高背景,三叠系为低背景,Ａｕ的高背景区呈ＮＷ向展布,这与右江裂谷区地壳演化的独特历史有关。桂西地区上古生界金主要来自深源,三叠系碎屑岩中金主要来自陆源。从Ａｕ元素丰度与存在形式考虑,高背景的碳酸盐岩夹泥岩、硅质岩、火山岩建造及毗邻的碎屑岩对金成矿更有利。     

基于多分辨分析的滤波算法在SAR图像斑点噪声消除中的应用

合成孔径雷达 (SAR)图像一般都存在相干噪声 ,对地物信息的提取及 SAR图像应用的干扰非常严重 ,对此许多人提出了不少处理方法 ,并分析对比了多种滤波算法 ,认为改良 K -均值自适应滤波效果最佳。本文中分析了改良 K -均值自适应滤波法的数学基础的局限性 ,并采用了一种基于多分辨分析的滤波算法 ,该算法通过将噪声 (或较小的结构特征 )与较大的结构特征相分离 ,然后滤出噪声 (或较小的结构特征 ) ,从而达到消除斑点噪声的目的。实验结果证明 ,基于多分辨分析的滤波算法在消除 SAR图像的斑点噪声方面优于改良 K -均值自适应滤波法。     

Point Cumulative Semivariogram for Identification of Heterogeneities in Regional Seismicity of Turkey

Geological events are neither isotropic nor homogeneous in their occurrences. These two properties present difficulties for spatial modeling of regionalized variables. This paper presents a point cumulative semivariogram (PCSV) technique for quantifying the heterogeneity characteristics of the phenomenon concerned. The basis of the methodology is to obtain experimental PCSVs for each measurement point which led to estimation of radius of influence around each site. In addition, the experimental PCSVs provide basic information about the heterogeneity of the geological variable in the region, and furthermore many useful interpretations can be made concerning the regional variability of the variable. It provides the measure of cumulative similarity of a regional variable around any measurement site. Because PCSV is a means of measuring total similarity, maps at fixed similarity levels are provided in order to document the regional heterogeneity. Identification of heterogeneities depends on the comparison of fixed PCSV values at a multitude of irregularly scattered sites. The PCSV methodology has been applied to the regional seismic data of Turkey.     

泥石流的结构两相流模型：I.理论

泥石流的运动既有类似于固液两相流之处,又在很程度上不同于固液两相流。在泥石流滨汉体模型,膨胀体模型,粘塑体模型及颗粒流模型研究的基础上,本文提出了一种新的模型－泥石流的“结构两相流模型”这种模具有以往各类模型的优点,同时又便于对不同类型的泥石流进行描述,在理论上,它比现行各类模型更加严密,在应用上,它较现行各类模式更加方便,能够适用于更加广泛的各类条件,泥石流的结构两相流模型中将现行模型的作为特例     

Silicon Isotope Geochemistry of Micro—Fine Disseminated Gold Deposits in SW Guizhou and NW Guangxi,China

Quartz was studied with respect to its silicon isotopic composition and cathodoluminescence in micro-fine disseminated gold deposits in SW Guizhou and NW Guangxi.The results showed that quartz in wall rocks.ores and that in association with hydrothermal silicification are distinctive in silicon isotopes and cathodoluminescence characters.Quartz in association with primary silicification is non-luminescent while that in wall rocks and associated with secondary silicification exhibits striking luminescence.Based on the dynamic fractionation of silicon isotopes,it is suggested that the mineralization was accompanied by rapid transport of aprimary siliceous fluid along the major deep fault system into subordinate faults before ore components deposited in favorable strata via penetration and metasomatism.Therefore,a deep origin is implicit for gold deposits of this type.     

The magma evolution of Tianchi volcano, Changbaishan

The Changbaishan Tianchi volcano is composed of the basaltic rocks at the shield-forming stage, the trachyte and pantellerite at the cone-forming stage and modern eruption. Studies on their REE, incompatible elements and Sr, Nd, Pb isotopes suggest that rocks at different stages have a common magma genesis and close evolution relationship with differentiation crystallization playing the key role. The co-eruption of basaltic trachyandesite magma and pantellerite magma indicates that there exist both crustal magma chamber and mantle magma reservoir beneath the Tianchi volcano. Project supported by the National Natural Science Foundation of China (Grant No. 49672109).     

煤矸石合成莫来石熟料研究

研究了煤矸石加氢氧化铝及氧化铝合成莫来石熟料的可行性。实验表明,采用煤矸石和氢氧化铝可在１５００℃完成莫来石化反应,到１５５０℃可得到接近理论密度的莫来石熟料,采用煤矸石和工业氧化铝反应,可在１５５０℃全部合成莫来石,到１６００℃可得到接近理论密度的莫来石熟料,采用煤矸石加α－Ａｌ２Ｏ３所得样品性能良好,化学成分最纯。     

A New Feature Vector Using Selected Line Spectra for Pulsar Signal Bispectrum Characteristic Analysis and Recognition

Average pulse profiles of pulsar signals are analyzed using the bispectrum tech-nique. The result shows that there are nonlinear phase couplings between the two frequency axes of the bispectrum charts, which indicate nonlinear factors in the generation and prop-agation of pulsar signals. Bispectra can be used as feature vectors of pulsar signals because of their being translation invariant. A one-dimension selected line spectrum algorithm for ex-tracting pulsar signal characteristic is proposed. Compared with selected bispectra, the pro-posed selected line spectra have the maximum interclass separability measurements from the point of view of the whole one-dimension feature vector. Recognition experiments on several pulsar signals received at several frequency bands are carried out. The result shows that the selected line spectrum algorithm is suitable for extracting pulsar signal characteristics and has a good classification performance.