GPS及RTK在桥梁复测中的精度探讨

探讨了应用GPS及RTK技术对桥梁施工控制网以及桥梁轴线复测的精度,并与常规的测量方法进行比较分析,得出了GPS及RTK技术可应用于桥梁控制网的建立和桥梁轴线点位的基础测量工作中.     

GPS在工程变形监测中的应用

与传统的工程变形监测方法相比,GPS测量技术在连续性、实时性和自动化程度等方面有明显的优势.在分析了GPS在变形监测方面的特点的基础上,探讨了GPS在大坝、地面沉降、高层建筑物等工程变形观测中的应用.     

利用GPS观测值反演电离层总电子含量的时空变化

为了便于电离层总电子含量时空变化的研究,利用区域电离层模型获得了GPS系统硬件延迟,从而进一步获取了绝对电离层总电子含量值.利用北京IGS站的GPS观测数据分别计算了2000年至2004年各个不同季节的总电子含量,经比较发现,电离层总电子含量表现出明显的季节性变化.利用中国地壳观测网络25个测站的观测数据计算发现,电离层总电子含量空间变化幅度大,在低纬度地区总电子含量值相对较大,而在中纬度地区相对较小.     

Insight into the 2004 Sumatra-Andaman earthquake from GPS measurements in southeast Asia

Data collected at approximately 60 Global Positioning System (GPS) sites in southeast Asia show the crustal deformation caused by the 26 December 2004 Sumatra-Andaman earthquake at an unprecedented large scale. Small but significant co-seismic jumps are clearly detected more than 3,000 km from the earthquake epicentre. The nearest sites, still more than 400 km away, show displacements of 10 cm or more. Here we show that the rupture plane for this earthquake must have been at least 1,000 km long and that non-homogeneous slip is required to fit the large displacement gradients revealed by the GPS measurements. Our kinematic analysis of the GPS recordings indicates that the centroid of released deformation is located at least 200 km north of the seismological epicentre. It also provides evidence that the rupture propagated northward sufficiently fast for stations in northern Thailand to have reached their final positions less than 10 min after the earthquake, hence ruling out the hypothesis of a silent slow aseismic rupture.     

基于GPS芯片的重力加速度测量仪

根据纬度和海拔高度对重力加速度的影响,通过GPS芯片测量,得到高精度的重力加速度值。该仪器具有制作简单,测量精度高,操作方便,价格低廉等优点。     

Deformation in the Three Gorges Reservoir after the first impoundment determined by GPS measurements

Currently,theongoingThreeGorgesProject(TGP)isthebiggesthydraulicprojectintheworld andtheThreeGorgesdamwillbeoneofthehighest dams.Standing185mhigh,itwillbeholding3.92×1010m3ofwaterwhencompletedin2009.Howev er,previousresearchesandhistoricalrecordshave shownthatsuchahugecontentofwatermighttrig germinorandmediateearthquakes[1—4],becausea decreaseoffrictiononanactivefaultduetoporepres surediffusenessandenhancedwaterpermeationcould causefaultintermittentunlockingtoreleaseseismic energy[4,5—8]…     

漂移区槽氧高压SOI-LDMOS器件模型

为了获得SOI-LDMOS器件耐压和比导通电阻的良好折衷,提出了一种漂移区槽氧SOI-LDMOS高压器件新结构．利用漂移区槽氧和栅、漏场板优化横向电场提高了横向耐压和漂移区的渗杂浓度．借助二维仿真软件对该器件的耐压和比导通电阻特性进行了研究,结果表明该器件与常规SOI—LDMOS结构相比在相同漂移区长度下耐压提高了31％．在相同耐压下比导通电阻降低了34．8％．     

GPS技术在和川引水枢纽测淤断面中的应用

对和川引水枢纽测淤断面D级GPS控制网的布设与实施情况进行了介绍,为在山区布设GPS控制网提供了很好的范例。     

Static slip model of the M w 9.0 Tohoku (Japan) earthquake: Results from joint inversion of terrestrial GPS data and seafloor GPS/acoustic data

Based on co-seismic displacements recorded by terrestrial GPS stations and seafloor GPS/acoustic stations, the static slip model of the 2011 Mw 9.0 Tohoku earthquake was determined by inverting the data using a layered earth model. According to a priori information, the rupture surface was modeled with a geometry that is close to the actual rupture, in which the fault dip angle increases with depth and the fault strike varies with the trend of the trench. As shown by the results inferred from the joint inversion, the "geodetic" moment is 3.68 × 10 22 Nm, corresponding to Mw 9.01, and the maximum slip is positioned at a depth of 13.5 km with a slip magnitude of 45.8 m. Rupture asperities with slip exceeding 10 m are mainly distributed from 39.6 to 36.97°N, over a length of almost 240 km along the trench. The slip was mostly concentrated at depths shallower than 40 km, up-dip of the hypocenter. "Checkerboard" tests reveal that a joint inversion of multiple datasets can resolve the slip distribution better than an inversion with terrestrial GPS data only-especially when aiming to resolve slip at shallow depths. Thus, the joint inversion results obtained by this work may provide a more reliable slip model than the results of other studies that are only derived from terrestrial GPS data or seismic waveform data.     

Bending-related faulting and mantle serpentinization at the Middle America trench

The dehydration of subducting oceanic crust and upper mantle has been inferred both to promote the partial melting leading to arc magmatism and to induce intraslab intermediate-depth earthquakes, at depths of 50-300 km. Yet there is still no consensus about how slab hydration occurs or where and how much chemically bound water is stored within the crust and mantle of the incoming plate. Here we document that bending-related faulting of the incoming plate at the Middle America trench creates a pervasive tectonic fabric that cuts across the crust, penetrating deep into the mantle. Faulting is active across the entire ocean trench slope, promoting hydration of the cold crust and upper mantle surrounding these deep active faults. The along-strike length and depth of penetration of these faults are also similar to the dimensions of the rupture area of intermediate-depth earthquakes.     

基于DSP采集和处理GPS信号的系统设计

介绍了带PCI接口的高速DSP及其外围电路的设计与基本软件的设计,本系统实现电力部门采集与控制GPS信号的功能.电气性能上,DSP采集并处理GPS信号,遵循CompactPCI协议规范实现与工控PC机的数据交换,进一步实现计算机网络控制.     

中国GPS联合收割机研究展望

概述了GPS联合收割机国内外的研究与发展状况,介绍了国外先进的GPS联合收割机及其智能测产技术,并在现有的GPS联合收割机智能测产的基础上,深入分析和探讨了有关作业质量控制的必要性,展示了我国GPS联合收割机需要智能测产和作业质量统筹兼顾的发展前景。     

西康线东岭黄土坡山体滑坡的防治措施

对于西康线东岭黄土坡路堑边坡所发育山体滑坡形成的地貌条件、岩石条件、构造条件，气候条件以及施工技术条件进行了初步的分析与研究，根据先期发生的小型山体滑坡，从地质学的角度进行了研究，指出现场滑坡产生的根本原因是地下水的活动直接影响了边坡土体的稳定性，加上施工破坏了边坡原有的稳定环境，进而造成了滑坡的发生。结合现场的实际情况，综合对比了几种治理措施的优劣。     

双频损耗调制型掺铒光纤环形激光器中的锁频与混沌

为了分析掺铒光纤激光器的非线性动力学特性,扩大产生混沌的参数范围,实验研究了采用2个正弦信号驱动的损耗调制型掺铒光纤环形激光器。该激光器在不同的调制参数条件下可产生锁频与混沌现象;随调制电压的增加,在锁频处通过倍周期分岔进入混沌;在非锁频处通过准周期进入混沌。实验发现频率比不同时由准周期转变为混沌所需调制电压不同,频率比等于黄金分割数时所需调制电压最低。在频率比保持不变时,该激光器可在不同调制电压比时产生混沌。结果表明:该激光器具有复杂的非线性动力学行为和更大的混沌参数空间。     

曲面拟合原理在GPS高程测量中的应用

介绍了曲面拟合原理,阐述了用曲面拟合原理进行GPS高程测量的布设原则,提出了提高其测量精度的方法。     

流体套管温度计测温原理及其测量误差的分析

从传热学角度分析套管温度计测量流体温度的物理模型,并阐述了其测温基本原理。通过实验数据和计算结果定量分析了该方法引起的测量误差的大小,探讨了产生测量误差的可能原因及影响误差大小的具体参数,总结出减小测温误差的基本途径和具体措施,对工程实际中提高测量精度有良好的效果。     

高精度偏心套的加工及检测

通过对出口偏心套与国内偏心套精度要求的对比，突出地体现了制造出口偏心套的技术难点，阐述了自行研制的大型专用工艺装备的原理，根据出口高精度偏心套的几何形体特征，采取了有效而又可靠的检测方法，成功地解决了高精度偏心套加工制造和精确检测的技术课题。     

电阻采样式变频器负载电流检测

分析了通用变频器直流母线串接检测电阻上的电流波形以及与负载电流之间的关系,并寻找其信号处理电路,使负载检测与过载、过流、短路保护均集中于该电阻上,最终使系统简化.给出了实际运用中的电流检测波形.     

室外消火栓撞断自锁机构设计

通过对室外消火栓结构进行分析，指出了目前室外消火栓结构上存在的缺陷，介绍了复式螺纹机构在室外消火栓中的应用，并运用强度分析理论对消火栓零件的强度进行了合理的设计，初步解决了室外消火栓被撞断后的自锁问题．     

用GPS／重力、地形确定山区正高

近年来人们往往利用GPS／重力来确定正常高,但正常高不同于表示绝地高程的正高,为此,笔者在GPS／重力确定正高方面作了一些研究,对由似大地水淮面转换成大地水淮面公式的意义及其误差,以及如何提高正高度精度都作了讨论,这于山区开发会有益的。