由余震分布确定大地震子断层及其参数的模糊聚类方法

大地震的破裂过程一般涉及多个断层的活动, 发震断层并非是单一断层平面, 而是由多个断层平面组合而成． 利用成丛小震发生在断层面附近的原则, 假定震源点围绕子断层面中心服从三维正态分布, 使用GK模糊聚类方法结合主成分分析给出了一种可以重构活动断层网络三维空间结构的新方法.该方法首先对全部震源点目录使用GK模糊聚类方法得到它的划分矩阵, 再利用划分矩阵及合适的阈值, 剔除离群震源点, 提取出平面型分布的子类, 最后对每个子类在三维正态分布的假设下确定断层面分布的95%置信矩形断层区域位置、 走向角和倾向角参数.当给定地震目录事件后, 可以给出符合假设的一系列最优断层面区域, 每个子断层由它的中心位置、 长度、 宽度、 走向角和倾角所刻画.为检验新方法的性能, 先进行计算机仿真, 结果显示算法可成功地重建模拟地震目录的断层部分.最后将新方法用于南加州兰德斯(Landers)地震部分余震精确定位数据中, 得到的重建结果与已知的研究结果比较吻合, 说明了新方法的有效性.      

江苏数字地震台网中心记录波形分析

对江苏数字地震台网的波形资料,从震相、频谱、振幅比3个方面进行对比分析,找出天然地震、人工爆破、塌陷的不同之处,能够在地震定位过程中快速识别,并将此方法在江苏地震台网实际工作中应用。     

Neural networks to simulate regional ground water levels affected by human activities

In arid regions, human activities like agriculture and industry often require large ground water extractions. Under these circumstances, appropriate ground water management policies are essential for preventing aquifer overdraft, and thereby protecting critical ecologic and economic objectives. Identification of such policies requires accurate simulation capability of the ground water system in response to hydrological, meteorological, and human factors. In this research, artificial neural networks (ANNs) were developed and applied to investigate the effects of these factors on ground water levels in the Minqin oasis, located in the lower reach of Shiyang River Basin, in Northwest China. Using data spanning 1980 through 1997, two ANNs were developed to model and simulate dynamic ground water levels for the two subregions of Xinhe and Xiqu. The ANN models achieved high predictive accuracy, validating to 0.37 m or less mean absolute error. Sensitivity analyses were conducted with the models demonstrating that agricultural ground water extraction for irrigation is the predominant factor responsible for declining ground water levels exacerbated by a reduction in regional surface water inflows. ANN simulations indicate that it is necessary to reduce the size of the irrigation area to mitigate ground water level declines in the oasis. Unlike previous research, this study demonstrates that ANN modeling can capture important temporally and spatially distributed human factors like agricultural practices and water extraction patterns on a regional basin (or subbasin) scale, providing both high-accuracy prediction capability and enhanced understanding of the critical factors influencing regional ground water conditions.     

在地震速报软件中集成多种信息发布手段初探

介绍江苏地震台网在地震速报软件中集成手机短信群发、多路电话语音群呼、自动传真和网站发布等多种信息发布手段的实现方法。实践表明,综合应用多种信息发布手段,并与速报软件直接集成,可以充分发挥各自优势,满足不同场合地震速报信息的发布需要,减少人工操作的中间环节,提高地震速报信息发布效率。     

不同环境条件下无菌和自然带菌波吉卵囊藻生长的比较

比较不同温度、光照及海水相对密度条件下无菌与自然带菌波吉卵囊藻(Oocystis borgei)生长的差异。结果表明:在20℃时,无菌藻的比增长率(μ)和叶绿素a(Chla)含量分别为0.398d-1和0.117mg/L,均显著高于带菌藻(P<0.05),在28和35℃时,无菌藻和带菌藻生长无显著性差异(P>0.05);在照度为16μmol·m-2·s-1时,无菌藻平均比增长率μ和Chla含量分别为0.345d-1和0.123mg/L,均显著高于带菌藻(P<0.05),在照度为39和88μmol·m-2·s-1条件下,无菌藻和带菌藻生长无显著性差异(P>0.05);在海水密度为1.007、1.020和1.030g/mL时,无菌藻和带菌藻的生长均无显著性差异(P>0.05),μ和Chla含量分别为0.325～0.374d-1和0.085～0.133mg/L。     

Preparation and biological efficacy of haddock bone calcium tablets

To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking (alkalinealcohol method) and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results show that the optimal parameters for the alkalinealcohol method are: NaOH concentration 1 mol/L, immersion time 30 h; ethanol concentration 60%, immersion time 15 h. A mixture of 2% polyvinylpyrrolidone in ethanol was used as an excipient at a ratio of 1:2 to full-cream milk powder, without the use of a disintegrating agent. This process provided satisfactory tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2 g·kg⁻¹·d⁻¹ or 5g·kg⁻¹·d⁻¹ significantly increased blood calcium and phosphorus levels and bone calcium content in rats. Therefore, these tablets could be used for calcium supplementation and prevent osteoporosis. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the added milk, may play positive roles in increasing absorption ratio.     

太阳2cm射电爆发精细结构的形态分析

本文介绍了北京师范大学天文系,在2cm波段上观测到的太阳射电精细结构(FS).这些FS都是叠加在微波爆发上的.其中重点对1990年5月23日与AR6063活动区成协的一个47GB型微波大爆发上叠加的FS的形态特征进行了分析.计算了几个有关的参数,并对结果进行了简单的讨论.     

2cm波段太阳射电爆发中的时间精细结构

本文首次报道了在1990年4—5月期间,2cm波段上叠加在微波爆发上的时间精细结构。     

Three-dimensional ionospheric tomography by an improved algebraic reconstruction technique

An improved algebraic reconstruction technique (IART) is presented for the tomographic reconstruction of ionospheric electron density (IED). This method applies the total electron content (TEC) measurements to invert the spatial distribution of the IED from a set of apriori IED distributions. In this new method, a data-driven adjustment of the relaxation parameter is performed to improve the computation efficiency and image quality of the classical algebraic reconstruction technique (ART). In addition, the new algorithm is also combined with ionospheric space discretization technique to simplify the inversion of IED, and it applies CHAMP occultation data to improve the vertical resolution. A numerical simulation experiment is carried out to validate the reliability of the new method. It is then applied to the inversion of IED from real GPS data. Inverted results show that the IART algorithm has better accuracy and efficiency than the conventional ART algorithm. The reliability of the IART algorithm is also validated by ionosonde data recorded at Wuhan station.