最优化因子处理及加权多重回归模型

因子的优劣是回归分析的关键。故在建立回归方程时,一般除对预报因子进行直线相关普查外,还要进行非线性相关普查。如将原因子x用x~(-1)、x~(1/2)、x~2 、e~x、In x等函数形式进行变换。但由于这些函数形式有限,故不一定能找到最优的表达形式;为此冯耀煌等仅给出了x~a和e~(ax)两种通式,其中a为待     

吉林延边地区汪清县大兴沟早二叠世华夏植物群的发现及其地质意义

吉林省延边地区汪清县大兴沟镇和盛村附近和盛组中首次采获大童植物化石:Lepidophylloides sp.,Stigmaria ficoides(Stemb.)Brongn.,Trizygia oblongifolium(Germ.et Kaulf.)Asama,Cal-amites cistii Brongn.,C...     

沁水盆地南部柿庄南区块煤层气地质特征

以国家科技重大专项《山西沁水盆地南部煤层气直井开发示范工程》成果为依据,以以往的地质勘查及研究成果为参考,对沁水盆地南部柿庄南区块煤层气地质特征进行分析。分析认为南部柿庄南区块构造简单,煤变质程度高、煤层厚度大、埋深适中而且分布稳定,有利于煤层气生成,煤层吸附能力较强,储层渗透率较好,煤层气保存条件好,是沁南煤层气勘探开发最有利区块之一。开发利用该区块煤层气资源,可有效改善地区能源结构、加快区域经济发展,降低后期煤炭开发风险,具有非常可观的社会及经济效益。     

N,N-二烷基酰胺类物质的膜状态及其在水面溢油集油剂中的应用研究

合成了 5种 N,N-二烷基酰胺型表面活性剂 ,并对其所成膜的状态进行了测定。表明当N,N-二烷基酰胺类物质单独成膜时获得的集油膜为多层膜 ,而当选用合适的溶剂与其配制成溶液以后 ,所成的集油膜则为转变膜或液态凝聚膜。在 5种 N,N-二烷基酰胺类物质中 ,酰基碳链越长、氮烷基碳链越短则其集油能力越强。应用 N,N-二烷基酰胺类物质配制了 4个配方 ,均具备良好的集油能力 ,并且对原油的集油能力大于对柴油的集油能力     

强震类型划分和后续强震预测方法探索

地震能量、振幅与周期的关系,由震源性质决定,因而其相关程度可作为强震类型划分的指标．初步将强震划分为主余震、双主震和强震群型3类．同类型强震在震源性质定量指标上有相似性,且有一定重复性．它们可为后续强震预测提供依据．从1988～1997 年50多例CDSN宽频带（BPZ波）强震记录中,分析得出的后续强震预测参考指标,对分型预测法应用有参考价值．     

A remote sensing environmental study of Haiko Bay——Ⅰ Tidal influx and its changes

Through the water areas extracted from remote sensing images and the combination of the methods for establishing the formula for calculating tidal influx with tidal data, the tidal influx of the Haikou Bay, Hainan Province was found to be 5.14×10⁷m³ in 1990, 5.80×10⁷m³ in 1984 and 5.05×10⁷m³ in 1965, respectively.After the analysis of the morphological and tidal range factors which determine tidal influx, this paper presents the trend of the changes in tidal influx caused by the changes in the morphological factors of the Haikou Bay.It is found that a decreasing trend was shown with a depressive rate of 2×10^-3during the period from 1965 to 1984, and an increasing trend with an incremental rate of 1×10^-3 during the period of 1984-1990.The main reason for the appearance of the decreasing trend before 1984 is the natural deposition and silting-up of the bay sediments; after 1984, the dredging and expansion of the Haikou Port and the Haikou New Port which caused an increase in water area at the mean low tide are the leading factor which causes the increase in tidal influx.     

Fractal generation of surface area of porous media

Many natural porous geological rock formations, as well as engineered porous structures, have fractal properties, i.e., they are self-similar over several length scales. While there have been many experimental and theoretical studies on how to quantify a fractal porous medium and on how to determine its fractal dimension, the numerical generation of a fractal pore structure with predefined statistical and scaling properties is somewhat scarcer. In the present paper a new numerical method for generating a three-dimensional porous medium with any desired probability density function (PDF) and autocorrelation function (ACF) is presented. The well-known Turning Bands Method (TBM) is modified to generate three-dimensional synthetic isotropic and anisotropic porous media with a Gaussian PDF and exponential-decay ACF. Porous media with other PDF's and ACF's are constructed with a nonlinear, iterative PDF and ACF transformation, whereby the arbitrary PDF is converted to an equivalent Gaussian PDF which is then simulated with the classical TBM. Employing a new method for the estimation of the surface area for a given porosity, the fractal dimensions of the surface area of the synthetic porous media generated in this way are then measured by classical fractal perimeter/area relationships. Different 3D porous media are simulated by varying the porosity and the correlation structure of the random field. The performance of the simulations is evaluated by checking the ensemble statistics, the mean, variance and ACF of the simulated random field. For a porous medium with Gaussian PDF, an average fractal dimension of approximately 2.76 is obtained which is in the range of values of actually measured fractal dimensions of molecular surfaces. For a porous medium with a non-Gaussian quadratic PDF the calculated fractal dimension appears to be consistently higher and averages 2.82. The results also show that the fractal dimension is neither strongly dependent of the porosity nor of the degree of anisotropy assumed.