KS－熵与混沌层次

有两种不同类型的混沌层次：一种得之于映射维数的增加；另一种则由不变环面分叉产生。通过计算相应的ＫＳ－熵，我们发现前者只是一种几何现象，后者则是本质的混沌层次，即伴随有混沌性的增加。     

线与面目标间拓扑关系的层次表达方法

拓扑关系已广泛应用于空间查询、相似性分析、制图综合、不一致性探测以及空间推理等实际应用中。本文研究IR2中一条线与一个简单面目标拓扑关系的描述和区分方法,采用的基本策略是分解与组合方法。首先,将线/面拓扑关系分为两类:基本关系和复合关系。其中复合关系描述为若干个基本关系的组合,即基本关系的一个集合。然后,提出了基本拓扑关系分类和区分方法,建立了相应的层次概念邻域图。针对复合拓扑关系,从空间集合的角度提出了具有三个层次的拓扑不变量,分别是(a)集合层次上的分离数和维数,(b)元素层次上的交分量类型和(c)综合层次上的交分量序列。分析发现,在IR2中一条线与一个简单面目标间具有16种潜在的基本关系。其中,它们的13种是描述复合线/面关系的基本构成单元。     

On the precision of age measurements by Rb-Sr isochrons in nontrivial cases

Calculations of isochrons by different methods are compared for the case when both variables are subject to error. Least-squares operations of the kind given by York (1969) and linear methods are compared. The advantage of the linear methods is demonstrated for the case of data reported by Housner and Brennan (1948), which we have modified for nonreplicated sampling. The sampling distribution of the slope is obtained and confidence intervals for it are given. The confidence intervals for the intercept on the ordinate and its distribution are obtained for fixed values of the slope. Examples of application of the method are given, based on data from the literature compiled in Appendix A.     

基于不变性矩特征的人工神经网络2-D形状识别

在2—D不变性矩快速计算的基础上，利用人工神经网络，使用不变性矩完成2—D形状的识别。实验结果与现有文献的结果比较，本文采用的方法具有特征数目少、意义统一、识别快速、准确的特点。     

地转效应实验平台低转速下均匀度相位分布测量

采用微机、光电脉冲技术并通过中断工作方式实现对旋转平台在低转速下转速均匀度相位分布的精密测量．为估计转台对旋转流体实验造成的误差提供数据，实现转台的转速精密测量，转速补偿和转速控制等方面的智能化     

A trial for monitoring temporal variation of seismic velocity using an ACROSS system

Abstract The temporal variation of seismic velocity near the Nojima Fault, which ruptured during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake), was detected using an accurately controlled routine-operated seismic source (ACROSS). The source generates elastic waves by a centrifugal force of an eccentric mass rotating around an axis. The mass is driven with an AC servomotor whose angular position is accurately controlled with reference to a very accurate global positioning system (GPS) clock. The error of the mass' position is less than 0.002 radian and does not accumulate. As a result, the source generates sinusoidal waves of very narrow spectral peaks enabling their detection with an excellent signal-to-noise ratio. Although the stability of the rotation is quite excellent, a large daily variation was found, which seems to be caused by changes in atmospheric temperature. The daily variation was 10% in amplitude and 0.1 radian in phase of the signal observed at the 800 m borehole seismometer. A significant variation was found to be due to that of coupling between the rotational source and the foundation made of reinforced concrete in which the source was situated. In order to make a correction on the signal of the 800 m borehole seismometer, the vibration of the foundation was measured and modeled assuming a rigid body movement. The correction successfully reduced the daily variation by approximately 90%, resulting in a variation of 1% in amplitude and 0.01 radian in phase. The phase variation of 0.01 radian corresponds to 100 μs and less than 0.1% in velocity over 1000 m between the source and the receiver.     

Study on relationship between deep and shallow structures along north boundary fault of Yanqing-Fanshan basin

IntroductionTheYanqing-Huailaibasin,whichconsistsoftheYanqing-FanshanandHuailai-Zhuolusub-basins,ismainlycontrolledbythenorthboundaryfaultsofthesub-basins.AsabasictectonicunitattheintersectionofthenortheasternendoftheNNE-trendingShanxigrabensystemandtheNW-trendingZhangjiakou-Penglaifaultzone,ithaskepttheintensivetectonicactivityintheQuaternary(YANG,1982;XU,DENG,1988;XU,MA,1992;FANG,etal,1993;Pavlides,etal,1999).Overthepastdecade,manyresearchershaveconductedstudiesonthedetailedstr…