特长隧洞（T7）正确贯通平面控制措施的探讨

本文就特长隧洞的正确贯通，提出了一些行之有效的平面控制措施，结合具体体情况，确定洞基本控制导线和布设形式以及洞内观测条件的合理选择。     

地下水观测井网规划中几个问题的探讨

地下水观测井网是掌握地下水动态 ,评价与研究地下水资源的基础设施。为了全面掌握地下水运动规律 ,进行地下水水情预报 ,以便更好地为地下水资源合理开发和管理养护服务 ,迫切需要对地下水观测井网进行全面规划和合理整顿。本文旨在对地下水观测井网分类及规划等问题进行探讨     

广州蓄能电站高压钢筋砼岔管现场模拟试验洞设计

广州抽水蓄能电站高压钢筋砼岔管现场模拟试验洞是一项大型的试验科研项目,它主要为广州抽水蓄能电站高压钢筋砼岔管服务。该文介绍这一现场模拟试验洞的试验目的、结构设计、观测设计及压水试验要求等方面的问题。     

Keeping baby safe: A randomized trial of a parent training program for infant and toddler motor vehicle injury prevention

Motor vehicle crashes are responsible for much death and disability among infants and toddlers. This study evaluated Keeping Baby Safe In and Around the Car, a multimedia DVD designed to improve knowledge about car seat installation among parents of infants and toddlers. The randomized controlled trial was conducted with 195 parents of children aged 0–24 months. Effective car seat use was evaluated via a written knowledge quiz and car seat simulation. Results from analyses of covariance models show that posttest scores for the intervention condition were significantly higher than those of the control condition on both knowledge and car seat simulation measures. The results, consistent across outcome measures and regardless of child age, suggest that viewing the Keeping Baby Safe In and Around the Car DVD resulted in significant gains in parents’ car seat knowledge and their ability to discriminate the critical elements of correct car seat installation. Dissemination of engaging multimedia DVDs such as this program might reduce motor vehicle crash-related injuries to infants and toddlers.     

News and Notes

This article contextualises documentary photographs taken of working-class holidaymakers in Blackpool by Humphrey Spender in the late 1930s. Working for Tom Harrisson's northern branch of Mass Observation, Spender recorded how the residents of ‘Worktown’ (Bolton, Lancashire) spent the ‘fifty-second week’ or summer holiday period of each year. Harrisson recruited Spender for this task because his camera was an ideal apparatus for recording the most mundane details of average British lives. Yet these images (indeed, all the photographs taken by Spender for Mass Observation) were used only sparingly by the organisation at the time of their creation. This article examines reasons for this, suggesting that Harrisson's understanding of photographic realism in combination with his perception of national identity served to highlight photography's ability to undermine rather than affirm the goals of Mass Observation as Harrisson had conceived them.     

李家峡水电站坝肩开挖岩体的声波测试

本文对声波试验的原理、方法作了简要介绍,并结合李家峡水电站工程一年来的实测资料,对该水电站两岸坝肩的波速分布;岩体的各向异性;波速与预裂孔线密度药量的关系;用锯末减震对水平建基保护;爆破对建基面影响的探测等问题进行了分析研究.     

付家岩滑坡变形特征及形成机理

长江三峡库区横跨川鄂褶皱带中段和川东弧形褶皱带东段,自然地质条件复杂,暴雨、洪水频繁,是我国滑坡等地质灾害高易发区之一。重庆市万州区是三峡库区地质灾害多发地区之一,付家岩滑坡为其中具代表性的一个,该滑坡对已建的移民迁建工程构成了严重威胁。本文在详细调查研究滑坡形成的地质环境条件、滑坡特征的基础上,通过监测数据的综合分析,深入系统地分析了该滑坡的变形特征、诱发因素和形成机制。     

GPS数据自动化下载与处理软件的设计与实现

介绍了CMONOC(中国地壳运动观测网络)数据共享系统的概况及自动化设计要求,阐述了GPS(全球定位系统)数据自动化下载与处理软件的设计方法,重点给出了利用V isual C 技术对CMONOC的GPS数据进行自动化下载与处理的编程实现。实际应用表明,该软件在长期的观测试验中运行可靠、操作方便,很好地满足了CMONOC工程应用的要求。     

基于频域扩展和SPECAN的全孔径TOPSAR成像算法

TOPSAR(Terrain Observation by Progressive scans SAR)是星载SAR的一种新工作模式,这种工作模式在保持ScanSAR宽测绘带优点的同时,解决了扇贝效应(scalloping)等问题,具有广泛的应用前景。针对TOPSAR信号在时域和频域都混叠的特点,该文提出了一种新的全孔径TOPSAR成像算法,算法利用频域扩展来解决TOPSAR的频域混叠问题,利用SPECAN(SPECtral ANalysis)技术来避免输出图像时域混叠,结构紧凑,处理效率较高。通过点阵目标和分布目标的仿真来验证了算法的有效性,并分析了算法的计算量,通过与几种现有的全孔径成像算法对比,说明了算法的高效性。     

基于二维Chirp-Z变换的星载TOPSAR成像算法

TOPSAR是一种新型的星载SAR宽幅测绘模式。该模式成像算法需要解决三大问题：多普勒频谱混叠、较大的距离徙动和方位输出时间混叠。针对这些问题,该文提出了一种基于2维Chirp-Z变换的成像算法,给出了该算法的完整推导过程和各传递函数的表达式。其中,方位去斜预滤波处理能够在较少的方位总采样点数下解决多普勒频谱混叠;距离向和方位向Chirp-Z变换能够分别完成距离徙动校正和方位信号聚焦。由于该算法只需要在方位向上增加较少的采样点数,且不涉及任何插值操作,故其具有较高的运算效率。仿真数据处理结果验证了提出成像算法的有效性。