超大口径钻孔施工技术

介绍了超大口径钻孔的应用领域及工程特点,阐述了不同施工方法的优缺点,通过案例分析系统地论证了多种钻进工法的设备配置、工艺流程以及关键过程的控制措施,总结了施工过程工艺和操作中应注意的一些问题。     

车载激光扫描数据控制点布设方案研究

该文以提高车载激光扫描数据高程精度为出发点,分析了扫描数据的误差来源。该文提出多种控制点布设方案,以京沪高速部分路段激光扫描数据为例,统计并分析各个控制点布设方案改正结果,为以后车载激光数据外业控制点布设提供参考。     

人工导斜补取煤心技术

在煤田地质钻探中,会由于各种原因,发生打漏、打丢煤层及煤心采取率不高等现象,达不到煤炭地质勘查钻孔质量标准,影响了对煤炭资源的评价。为了补救的地质资料,必须进行补取煤岩心。为安全完整的补取煤心,首先加工偏斜器,将其加工成圆弧状,斜面光滑平整,背面曲直,上、中、下段预留一个直径为2cm的圆孔,末端加工成尖形;其次,侧开窗位置选择在井壁完整硬度低的泥岩段,一般距煤层顶10~15m;再次,采用水泥砂浆及不规则碎石块建造牢固的人工孔底,并固定好偏斜器,使其不易滑动;最后,通过合适的钻具组合及施工参数,可安全顺利的补救缺失地质资料。本次补心岩层段长度采取率80%,煤层段长度采取率87%,满足煤田地质钻探质量要求,效果良好。     

基于几何约束与局部描述的航空影像直线匹配

针对航空影像场景复杂,干扰直线匹配的不确定因素较多的问题,本文提出了基于几何编组与局部均值标准差直线描述符(MSLD)的直线匹配算法。首先,利用直线检测器(LSD)获得影像的直线特征信息,将直线与直线间的几何特征作为约束条件进行编组,获得两幅航空影像的直线对;其次,运用核线约束确定候选直线对,并依次构建参考与候选直线对的支持区域,利用仿射不变性统一支持区域的大小,借助MSLD进行直线对外观的局部描述;然后,结合欧氏距离与最邻近比值计算航空影像中直线描述符间的相似性,进而确定匹配结果;最后,结合共线约束完成对匹配结果的检核,获取精确的同名直线。试验选择不同场景类型变换下的航空影像数据,结果证明了本文算法可以较好地应对航空影像直线匹配效果不佳的现象。     

A hybrid method for optimization of the adaptive Goldstein filter

The Goldstein filter is a well-known filter for interferometric filtering in the frequency domain. The main parameter of this filter, alpha, is set as a power of the filtering function. Depending on it, considered areas are strongly or weakly filtered. Several variants have been developed to adaptively determine alpha using different indicators such as the coherence, and phase standard deviation. The common objective of these methods is to prevent areas with low noise from being over filtered while simultaneously allowing stronger filtering over areas with high noise. However, the estimators of these indicators are biased in the real world and the optimal model to accurately determine the functional relationship between the indicators and alpha is also not clear. As a result, the filter always under- or over-filters and is rarely correct. The study presented in this paper aims to achieve accurate alpha estimation by correcting the biased estimator using homogeneous pixel selection and bootstrapping algorithms, and by developing an optimal nonlinear model to determine alpha. In addition, an iteration is also merged into the filtering procedure to suppress the high noise over incoherent areas. The experimental results from synthetic and real data show that the new filter works well under a variety of conditions and offers better and more reliable performance when compared to existing approaches.     

基于标准差方法的地缘环境单元划分研究

地缘环境是由地理位置相互联系并产生关系的环境.文中提出将地缘环境指标分为本底、关联及位势3大类,其中本底指标又被分为社会经济、政治军事、战略资源和生态环境4类,各类又被细分为4个子类,各指标之间可以通过加权叠加方法进行综合生成指标体系.标准差反映数据与其平均值之间的离散程度.文中以标准差法为划分方法,以地缘环境指标体系及其加权叠加为划分依据,对我国周边地缘环境中的敏感地区之一——南亚进行了地缘环境单元划分实验.实验结果表明标准差方法在地缘环境单元划分中表现有效且准确.     

合成孔径雷达高度计波形重跟踪算法的近岸精度分析

针对近岸区域,基于Sentinel-3A合成孔径雷达观测数据,选取多阈值、ICE1、IceSheet和SAMOSA四种波形重跟踪算法,利用全球范围内27个验潮站海面高数据,分析近岸20 km范围内4种波形重跟踪算法的精度。结果表明,多阈值算法在近岸6 km范围内可保留最多的有效波形,且与验潮站海面高数据具有最高的相关性和最小的均方根误差;SAMOSA算法在离岸距离大于5 km时相对大地水准面稳定性最高,更适用于开阔海域。     

Mapping the sea surface using a GPS buoy

On May 22 and 24, 1995, a buoy, designed to float with the water surface and equipped with a GPS antenna, was deployed off the California coast at 16 locations near the Texaco oil platform, Harvest. The purpose of this deployment was threefold:.(1) to demonstrate the ability of this style of buoy to calibrate the TOPEXIPOSEIDON (TIP) altimeter range measurement as it overflew the platform: (2) to demonstrate the ability of the buoy to map the ocean's surface over a 10‐km‐diameter circle surrounding platform Harvest; and (3) to demonstrate the ability of the buoy to measure the sea state accurately. During the 1.6‐h period surrounding the time of the TIP overflight, the buoy‐measured sea level never differed by more than 1.5 cm from the sea level measured by the National Oceanic and Atmospheric Administration (NOAA) acoustic tide gauge on the platform. The good agreement demonstrated the capability of this style of buoy to calibrate altimetric satellites. A paraboloid was fitted to sea level from 16 buoy locations surrounding the platform with a 2.5‐cm rms residual. On a 10‐km‐diameter circle centered on the platform, the paraboloid was within 2.4‐cm rms of the Ohio State University Mean Sea Surface (OSUMSS95). H _u3 values calculated around the overflight times from the GPS buoy vertical positions had a mean difference of 2 cm and a standard deviation of 18 cm from values calculated from the University of Colorado (CU) pressure gauge system. At the time of the overflight, H _u3 was near 2 m, while 3‐m seas were observed by the CU pressure system during measurements later in the day. This experiment demonstrates that a simple wave‐rider buoy design can give comparable accuracies to that of more complex GPS platforms such as the University of Colorado's spar buoy, but is much easier to deploy and capable of being used in more severe weather conditions. Thus, such a buoy and derivative designs have great potential for calibrating altimetric experiments, and for oceanographic and geodetic mapping experiments.     

基岩大口径垂直钻孔施工实践

针对基岩中施工大直径垂直钻孔的难点,介绍了采用小径导向孔、加放活导向器、用小径导向孔对大口径钻孔进行监测、使用具有超前导向的大口径扩孔钻头等技术措施,成功实现了在基岩中施工大口径垂直钻孔和全孔下放大直径钢管的施工过程。     

甘肃省县域经济差异时空分异及影响因子研究

不同因子对区域经济差异的影响一直是国内外学者关注的重点及热点问题,探究县域经济时间过程演变和空间格局分异的主导影响因子,科学揭示各因子的作用机制,将为区域经济发展战略的制定提供重要指导依据。本文以甘肃省县域为研究单元,利用空间化表达、标准差椭圆分析县域经济空间分异现象,借助多元线性逐步回归和地理探测器对县域经济时空分异影响因素进行探讨。研究结果表明：① 甘肃省县域经济之间的总体差异明显,随时间波动较大;② 县域经济空间分布重心不稳定,变动较大;③ 财政收入、城镇化率和工业产业比重是主导的时间影响因子;④ 铁路密度、公路密度、河流密度是甘肃省县域经济空间分异的主要地理因子,且因子之间的交互作用强于单因子对经济空间分异的作用。在协调县域经济发展过程中,应根据主要影响因素精准实施发展策略,合理利用因子之间的交互作用,加快经济协调发展。