基于建筑抗震设计规范的设计用地震动分析

首先利用我国《建筑抗震设计规范》(GB 50011-2001)中的地震影响系数曲线,制成适合于我国抗震设计规范的人工地震波形,然后使用该人工波和日本现行设计用地震动,对隔震结构进行地震响应分析,最后由地震响应结果对所提出的模拟设计用地震动大小进行评价,得到一些有意义结论,供抗震设计人员在设计时参考。     

场地地震安全性评价中确定设计地震动参数方面若干问题的研究

研究了确定设计地震动参数中涉及的若干问题,其中包括基岩水平加速度反应谱衰减关系的选择、震源深度对基岩水平加速度峰值及基岩反应谱曲线的影响、强度包络线函数及输入随机相位的选择、土体非线性特性参数和土层剪切波速值的选择、设计地震动反应谱的标定等问题。在有关方面的研究中基于一个典型场地计算剖面,采用一维等效线性化模型并通过逐项变换某些研究参数的方法,研究了有关方面对设计地震动参数可能产生的影响及存在的误差和相应的规律,有关研究结果对合理确定设计地震动参数具有一定的实用价值。     

铜合金可见光谱特征及其应用

对铜合金可见光谱线进行了计算机数字模拟处理，研究了基体元素铜和各成分元素的可见光谱特征。使用光栅看谱镜和棱镜看谱镜对铜合金可见光谱进行了看谱分析研究，摄制了彩色图谱。利用铜元素及成分元素特征谱线进行了基体鉴别和成分元素分析，研究结果可用于合金基体鉴别及铜合金成分元素的定性和半定量分析。     

Theoretical relationship between SSA and MESA with both application

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库车河铜场水库的人工合成基岩地震动加速度时程

针对所承担工程任务的要求,采用目前较为成熟的数值计算方法,将根据地震危险性分析计算得到的库车河铜场水库的地震动参数（３ 种概率水平）转换成模拟的地震动加速度时程。因为计算中直接采用了新疆地区乌恰强余震频谱,合成的基岩地震动加速度时程很好地反映了该地区的工程特性     

共和地震前后中小地震的波谱变化

利用ＣＤＳＮ兰州台的短周期（ＳＰ）地震记录资料,对１９９０年４月２６日青海共和７．０级地震前后发生在该地区的３５个前,余震作了波谱分析工作。结果表明,主震前,共和地区小地震的纵,横波位移谱的拐角频率比值ｆｃ（Ｐ）／ｆｃ（Ｓ）为１．８左右。主震后,拐角频率比下降到１．３左右,１９９５年以后,拐角频率比值又上升到１．５左右,拐角频率比值有可能成为监测孕震区内应力状态变化的测振学指标。     

Walsh spectra of gravity anomalies over some simple sources

Walsh transform of gravity anomalies over a point mass, a horizontal and a vertical line mass have been computed to obtain a cyclic shift invariant differential energy density (DED) function. Quantitative relations between DED spectral characteristics with depth to centroid/top of the source have been established. The effects of profile length, sampling interval, random noise and zero padding have been investigated. Applicability of the proposed method has been evaluated through two field examples.     

Periodicity in midwest US climatic data: the Hale cycle signal or the luni-solar signal?

Cohen and Sweeter (1975) found the 20 to 22-year Hale (double sunspot) cycle signal in the maximum entropy spectra of sunspot and Atlantic tropical cyclone data. Currie (1996) corroborated and extended their analysis, but he argued that this signal is the 18.6-year luni-solar tidal constituent. Currie maintains that Cohen and Sweeter mistakenly conjectured that this long term periodicity was induced by the 20 to 22-year Hale cycle signal. However, no further investigation of periodicity in the extracted wave forms corresponding to the 18.6-year luni-solar signal was conducted. In this study, we follow Currie's signal processing procedures to extract the wave forms corresponding to the 18.6-year luni-solar signal. In order to investigate the periodicity in the extracted wave forms, multi-taper method (MTM) is used for harmonic analysis. Band pass filters are then designed to extract the wave forms corresponding to the individual components identified in the MTM harmonic analysis. The investigation results of the monthly precipitation and Palmer's drought severity index (PDSI) data in three of the midwestern states – Illinois, Indiana and Ohio – show that two periodic components, the 20 to 22-year Hale cycle signal and the other component with periods between 16.9 and 13.5 years, are identified. The bistability phenomenon, which Currie found in these wave forms, is more likely to result from the superposition of these two periodic components, rather than from a nonlinear mechanism. Besides, a periodic component with an approximate period of 33 years is detected.     

Study of characteristics of long-period ground motion response spectra by using broad-band records of the Chinese digital Seismograph Network

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A model for solar quiet day variation at low latitude from past observations using singular spectrum analysis

Singular spectrum isolates significant principal components in a time series from the embedded noise. This tool-kit is used to reconstruct trend-free individual time series, formed by restricting the mean monthly hourly values of geomagnetic field to one hour at a time at a low latitude station Alibag (dipole latitude 9.5°N). Each reconstructed component is extrapolated over the next 12 values using an autoregressive model based on Burg’s maximum entropy algorithm. Details of a numerical approach to increase the reliability of extrapolation are highlighted. The extrapolated reconstructed components are then combined to generate predicted monthly values for each hour. The mean diurnal variation for any month obtained from the extrapolated individual hourly time series compares favorably with the observations. This approach to Sq(H) modelling incorporating both long and short term variations will be beneficial in the derivation of Dst index.