基于神经网络的建筑物沉降原因分析

在我们应用回归方法对建筑物沉降原因分析及沉降趋势的预测中，由于实际情况的复杂性及主观认识的局限性，这样所得的结果含有较多的人为因素，可能会与实际情况有所差异。针对这种情况，讨论了应用神经网络方法来发现和验证引起建筑物沉降的因素及对沉降趋势的预测。实例表明，该方法能取得较好的效果。     

谈县级地震部门依法管理建设工程抗震设防要求

以山西省祁县依法管理工程抗震设防要求为例，论述了强制性审核、确定一般工业、民用建设工程抗震设防要求的重要性及其深远意义。结合工作实际．总结了部分依法行政、规范管理和落实抗震设防要求的经验。     

The effect of bed mobility on resistance to overland flow

When sediment grains are transported as bed load in overland flow, there is a net transfer of momentum from the flow to the grains. When these grains collide with other grains, whether on the bed or in the flow, streamwise flow velocity decreases and resistance to flow increases. Resistance to flow generated in this manner is termed bed‐load transport resistance. Resistance to flow f over a plane bed may be partitioned into grain resistance f_g and bed‐load transport resistance f_bt. We use the symbols f_btf and f_btm to denote f_bt for flows over fixed beds and over mobile beds, respectively, and we compute the effect of bed mobility on flow resistance f_mob by subtracting f_btf from f_btm. The data for this study come from 54 flume experiments with fixed beds and 38 with mobile beds. On average f_mob is approximately equal to half of f_btm, which is about one‐quarter of f. Hence, f_mob is about one‐tenth of f. Predictive equations are developed for f_btf, f_btm and f_mob using dimensional analysis to identify the relevant independent variables and regression analysis to evaluate the coefficients associated with these variables. Values of f_mob are always positive which implies that mobile beds offer greater resistance to flow than do fixed beds. Evidently bed‐load grains colliding with mobile beds lose more momentum to the bed than do grains colliding with fixed beds. In other words, grain collisions with mobile beds are less elastic than those with fixed beds. Copyright © 2005 John Wiley & Sons, Ltd.     

格尔木井水温异常特征及其与地震关系分析

简要介绍了格尔木井水温动态观测的环境与条件,在研究正常动态特征和影响因素的基础上,对水温异常的映震关系进行了分析,并成功地进行了一次短临地震趋势预测。探讨了水温异常的形成原因。     

东北地区矿业开发态势与矿山环境地质问题综合研究

在论述东北地区矿业开发态势的同时,阐述了区内能源矿产、金属矿产及非金属矿产开采引发的主要环境地质问题,针对区内复杂的矿山环境地质问题现状,提出了开展东北地区矿山环境地质综合研究问题的工作思路.     

森林沼泽景观区中大比例尺化探找矿工作方法的研究--记大梁金矿的发现

大梁金矿是通过森林沼泽景观区开展1：50000和1：25000地球化学测量及综合地质工作而发现的,证明采用的森林沼泽景观中大比例尺化探方法是行之有效的.     

桩底注浆钻孔灌注桩承载力的研究

通过天津地区几例钻孔灌注桩桩底注浆的静载荷试桩结果 ,分析天津地区钻孔灌注桩桩底注浆单桩竖向极限承载力标准值的估算方法     

沉管灌注桩大面积断桩原因分析

通过2个工程实例分析了沉管灌注桩出现大面积断桩的原因是由于后期基坑开挖不当造成的，并提出了预防断桩出现的一些措施以及对断桩的处理补救措施。     

北方农牧交错带退耕还林还草经济政策优化调控

退耕还林还草作为北方农牧交错带生态重建的切入点,在实际操作中也不可避免地存在一定的问题。文章对当前退耕还林还草的社会经济特征、政策安排、协调机制及制约因素进行了分析。提出:区域粮食适度自给定位、部门协调机制创新、产权制度改革、区域产业专业化分工、适度生态移民及建立生态补偿机制为进行政策优化调控的主要途径。     

Two new species of mid-Cretaceous webspinners in amber from northern Myanmar (Embiodea: Clothodidae,Oligotomidae)

Two new genera and species of Cretaceous webspinners (Embiodea) are described and figured, both preserved in amber from northern Myanmar. Atmetoclothoda orthotenes Engel and Huang, gen. et sp. nov., is the first fossil representative of the putatively primitive family Clothodidae, and is segregated into its own subfamily, Atmetoclothodinae Engel and Huang, subfam. nov., owing to its primitive retention of a distinct mentum, a quadrate submentum with straight borders, a postocciptal suture that meets the hypostomal sulcus at the posterior tentorial pit, and subgenae that do not meet medially (thus a ventral bridge or gula is lacking), completely symmetrical terminalia, and unsegmented cerci that apically bear a small inner lamellar projection. Litoclostes delicatus Engel and Huang, gen. et sp. nov., is the first definitive fossil of Oligotomidae (not including a subfossil species in Pleistocene copal and which is likely synonymous with an extant taxon), and differs from modern genera in a combination of head, tarsal, and terminalic morphology. The new fossil species double the known Cretaceous fossils and add a further two families to the Mesozoic record for the order.