一种人口连续分布模型的研究

分析了常用的表示人口分布的方法及其不足，提出了将人口统计数据空间分布化的方法，将研究区域划分为一定分辨率的格网，用距离衰减函数将人口密度估计值分配到每个格网上，每个格网上的人口是均匀分布的，随着格网分辨率的提高，就可以模拟出符合人口说细分布的人口密度空间连续分布模型，并通过实验说明该方法是可行的。     

Atmospheric Turbulence Decay During the Solar Total Eclipse of 11 August 1999

The studies of turbulence decay were based in the past on measurements carried out in neutrally stratified wind tunnels and, more recently, on large-eddy simulation runs. Here the atmospheric turbulence decay process during the solar total eclipse of 11 August 1999 is examined. Thus a rapid transition from convective boundary-layer turbulence to that of a neutral or slightly stable one is considered. A u-v-w propeller anemometer and a fast response temperature sensor located in northern France on top of a 9-m mast recorded the turbulence observations. The measurements, in terms of turbulent kinetic energy decay with time, were found to be in good agreement with those prescribed by a theoretical model of turbulence decay recently proposed. In particular, it was found that the exponent of the power law describing the decay process has the value -2.     

Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.     

主成分与主成分估计

在测量数据处理中,当设计阵存在复共线时,最小二乘估计的性质将变得不好,本文应用主成分估计来改进最小二乘估计。一方面是因为主成分估计具有一些好的性质,另一方面与岭估计和广义岭估计相比,主成分估计的偏参数选取要简便得多,从而大大提高了实用价值。     

Q P and Q S in Beijing and Jianchuan, Yunnan areas

Events from the December 1982 Huairou County, Beijing, and the July 1982 Jianchuan, Yunnan earthquake series were recorded at one station in Beijing City and at four stations in Eryuan area, Yunnan, respectively. Dividing the spectra (for P and S waves) from the smaller events in the series by spectra (for corresponding P and S waves) from the larger events in cach region, we have determined the high frequency source spectral decay rate to be ω⁻¹in both cases. Through trial and error method, we are able to determine the appropriate constantQ _P andQ _S that corrects the individual spectra to the proper high frequency decay rate. It is found that aQ _P of 800 and aQ _S of 550 can adequately compensate for the attenuation of the waves in Beijing area. For Jianchuan, Yunnan area the corresponding values are 900 and 400. This subject is supported by Chinese Joint Seismological Science Foundation.     

灰色系统GM(n,m)模型参数的递推估计和时变估计

本文给出灰色系统GM(n,m)模型参数的递推最小二乘估计和时变参数估计,前者的优点是可以避免反复求逆矩阵,因而使计算简便,同时克服了文献1中给出的估计方法当观察数据多、矩阵线数高、分配单元增加时,微型机容量不够的弱点,而且随着新数据的到来,通过递推算法自动对系统参数加以修正,提高了模型的自适应性;时变参数估计可以缩小系统的时变性与模型参数非时变性所产生的差异。     

高分辨率勘探与地震仪器

本文较系统地讨论了地震勘探中振幅动态范围与仪器动态范围的基本概念,指出仪器动态范围是开展高分辨率勘探的极为重要的一个基本条件,它要根据浅层强信号与深层高频弱信号的振幅动态范围来设计.如果仪器动态范围小,就录制不上高频信号,必然降低分辨率.文中也简介了在高分辨率地震勘探中如何选取最佳仪器因素的一些做法.     

工程岩体强度的估算方法

岩体是由地质过程中形成的岩块和结构面网络组成。由于试件制备、加荷等均极困难,且昂贵而费时,难于像岩块那样进行大量试验来确定岩体之强度。所以,如何通过室内小试件试验来估算大岩体的强度成为工程地质工作者所关注的问题。本文介绍了两种用小试件资料估算大岩体强度的方法及计算实例。     

谱特征参数在评价激电异常源性质中的应用

从研究激电场频谱特征及充、放电时间特征出发,根据实验观测结果,总结了硫化物矿化体(黄铜矿)及含石墨白云质大理岩等岩性的频谱特征及充放电时间特征,探索到新的定性评价激电异常源参数——频率谱及时间谱、视衰减速度。实践证明,利用频率谱定性评价硫化物矿化体(黄铜矿)与含石墨白云质大理岩激电异常源取得较佳效果。     

Ecological requirements of Ostracoda (Crustacea) in three types of springs in Turkey

Seasonal occurrence of six ostracod species (Psychrodromus olivaceus, Potamocypris villosa, Ilyocypris inermis, Candona candida, Candona neglecta, and Cypridopsis vidua) varied from May 2003 to June 2004 in three types of spring (Limnocrene, Helocrene, Rheocrene). When I. inermis was only found in the limnocrene spring each month, P. olivaceus was common in all types of springs. The other four ostracods were found in the helocrene spring in fall, winter, and spring seasons. The unweighted pair group mean averages dendrogram separated three main clusters. The first cluster includes two species (C. vidua, C. candida) while I. inermis was found in the second cluster and P. olivaceus, C. neglecta, and P. villosa were found in the third. The occurrence of P. olivaceus and C. neglecta and P. villosa and C. candida was strongly correlated to each other (r=0.750 and 0.850, respectively). The Pearson correlation analyses showed a strong negative relationship between C. neglecta and water temperature (r=−0.607), but other species did not show any significant correlation to any of the environmental variables used (P>0.05). Canonical correspondence analyses (CCA) displayed all species closer to the center of the dendrogram, indicating high levels of species tolerances to environmental variables. Thus, the first axis of the CCA diagram explained 80% of the relationship between six species and five environmental variables.