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31.
In this paper, the South China coastal area is divided into several fault block areas (first class), sub-areas (second class) and mini-areas (third class) based on their dynamic signs, heridity, uniformity, paricu-larity and the mode of action of tectonic stress. Their tectonic geomorphological features are elaborated and the amplitude as well as the rate of relative motion since the end of the late Pleistocene epoch are estimated from 14C data of the samples which fundamentally repres 相似文献
32.
This contribution discusses the application of Chebyshev Type I filter for processing real earthquake records. Consideration
is given to the effects of filtering parameters (passband amplitude ripple and order of the filter) on the time series, strong-motion
parameters, Fourier Amplitude Spectrum of acceleration, and elastic displacement response spectra. Time histories of five
earthquakes with different moment magnitudes have been examined (from stations located close to the epicenters). Data processing
is based on application of bandpass Chebyshev filtering over frequency range with substantial signal to noise ratio (level
of 3 or approximately 3 dB). Applying different filters, we have monitored several important strong-motion parameters: peak
values of acceleration, velocity, and displacement; Arias intensity, acceleration/velocity spectrum intensity, significant
duration, etc. Some new results and conclusions concerning the influence of Chebyshev filter in data processing of records
have been summarized. The graphical and numerical outcomes obtained, as well as the comparison with a Butterworth causal filter,
are included in the work. The results could be potentially useful to engineering seismologists who need to evaluate and better
understand the merits of this type of filtering for strong-motion data processing. 相似文献
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35.
利用改进的TurboEdit算法与Chebyshev多项式探测与修复周跳 总被引:1,自引:0,他引:1
根据利用TurboEdit方法对GPS观测数据进行周跳探测的特点,设计了固定弧段长度的滑动窗口拟合模型,对其中的Geometry-Free组合法进行改进;在探测出周跳后,利用最小二乘Chebyshev多项式拟合来修复周跳。实验结果表明,改进后的TurboEdit算法可以探测出等周的1周小周跳、等周的大周跳和连续的小周跳、大周跳,同时,最小二乘Chebyshev多项式拟合可以精确修复以上周跳对。 相似文献
36.
文中分别采用拉格朗日多项式和切比雪夫多项式,对时间间隔为15 min的IGS精密星历进行内插和拟合,将插值结果与原始精密星历进行比较。在此基础上分析了不同阶数下的插值精度,并将这两种方法做一些比较,得出结论:采用一定阶次的拉格朗日和切比雪夫多项式做精密星历内插均达到毫米级的精度,且两种方法的插值效果比较接近。 相似文献
37.
地震射线走时的求取方法是叠前时间偏移研究的核心问题之一,也是影响计算时间域角道集角度精确性的关键因素之一.本文基于Kirchhoff叠前时间偏移,应用第一类切比雪夫多项式,对弯曲射线对称走时加以改进,引进非对称项,优化后得到切比雪夫非对称走时方程,与高精度走时进行比较和误差分析,再将该走时求取方法应用于时间域角道集的求取中,得到地下较真实的入射角.通过模型计算和实际地震资料处理证明,此种非对称走时及其角道集的求取方法具有精度高、计算量少的优点. 相似文献
38.
The present article examines whether Late Holocene climate-induced vegetation changes in the Central African forest block may have facilitated the Bantu Expansion. This is done through a body of evidence that is not commonly used for the reconstruction of vegetation dynamics, i.e. language data. The article focuses on common Bantu vocabulary for three pioneer species abundantly present in the Central African pollen record between ca. 2500 and 2000 BP: Musanga cecropioides, Elaeis guineensis, and Canarium schweinfurthii. The geographical distribution patterns of the vernacular names for these pioneer trees add weight to the hypothesis according to which the rainforest contraction that emerged in the first millennium BC had an impact on the way Bantu languages dispersed. 相似文献
39.
By using field survey data from the sixth forest inventory of Jiangxi Province in 2003, the biomass and carbon storage for three studied species (Pinus massoniana, Cunninghamia lanceolata, and Pinus elliottii) were estimated in Taihe and Xingguo counties of Boyang Lake Basin, Jiangxi Province, China. The relationship between carbon density and forest age was analyzed by logistic equations. Spatio-temporal dynamics of forest biomass and carbon storage in 1985-2003 were also described. The results show that total stand area of the three forest species was 3.10 × 10^5 ha, total biomass 22.20 Tg, vegetation carbon storage 13.07 Tg C, and average carbon density 42.36 Mg C/ha in the study area in 2003. Carbon storage by forest type in descending order was: P. massoniana, C. lanceolata and P. elliottii. Carbon storage by forest age group in descending order was: middle stand, young stand, near-mature stand and mature stand. Carbon storage by plantation forests was 1.89 times higher than that by natural forests. Carbon density of the three species increased 8.58 Mg C/ha during the study period. The carbon density of Taihe County was higher in the east and west, and lower in the middle. The carbon density of Xingguo County was higher in the northeast and lower in the middle. In general, the carbon density increased with altitude and gradient. Afforestation projects contribute significantly to increasing stand area and carbon storage. Appropriate forest management may improve the carbon sequestration capacity of forest ecosystems. 相似文献
40.
考虑到对精密星历插值的重要意义,采用Langrange插值和Chebyshev插值对IGS提供的1d的精密星历进行插值,并对插值精度做了对比分析。结果表明,2种插值方法中间时段插值精度较高,但边缘时段的插值精度差;而且由于IGS提供的精密星历是每隔15 min或5 min的卫星坐标,不可避免的对某些时段进行了外推,这样一来外推时段处的精度就不能保证。针对这些问题,提出了对不同时段采用不同的阶次、不同的间隔进行卫星轨道插值的方法,实验证明这种处理方法可以使1 d任意时刻的插值精度达到mm级。 相似文献