大跨斜拉桥悬臂端钢箱梁上监测点高程测量新方法

在斜拉桥的主梁施工中,需要高精度测量悬臂端钢箱梁的高程。随着悬臂的增长,桥面的晃动越来越大,水准仪读数的难度也越来越大,甚至读不出数据;同时由于梁面上施工设备的影响,测量的难度很大,时间也很长。本文提出采用Leica TCA2003全站仪测量高差和水准仪测量工作基点高程相结合的方法,测量钢箱梁上监测点的高程,通过理论分析和对比实验证明了该方法的可行性。     

GPS RTK联合全站仪在唐山煤矿塌陷区测图中的应用与研究

GPS测量技术能够实时地提供测站点厘米级的3维坐标,速度快、精度高,但应用范围受天气、地域条件、卫星运行等环境因素限制[1]。全站仪是自动化程度很高的野外测量仪器,精度高、应用广,但受通视条件、测量距离等因素制约。本文根据在唐山煤矿塌陷区测量中的测量区域成带状分布、面积广、密集的防护林让卫星信号变弱的实际情况讨论了两者的有机结合,探索出GPS RTK与全站仪相配合进行塌陷区测量的作业方法,使用这两种仪器在实际测量中,提高了测图的工作效率、减少了外界的干扰、降低了作业人员的劳动强度,点位精度得到有效的保证,并对遇到的碎部点精度问题提出了RTK与全站仪相互检测的方法。在此基础上,研究将卫星接收机与全站仪集成,研制物理结构和数据处理一体化的低成本智能化仪器,解决在特种环境下定位效率低、精度低、可靠性差、干扰因子多的瓶颈技术问题,实现特种环境中高精度、低成本、实时定位与精准监测的功能。     

全站仪悬高测量存在的问题及改进方法

通过对全站仪悬高测量基本原理的介绍,结合在实际工程中应用时存在的问题,提出了安置两次仪器对同一目标进行观测,并对所测结果进行改正,提高测量成果的精确性。     

Carbon dioxide dynamics in rivers and coastal waters of the “big island” of Hawaii,USA, during baseline and heavy rain conditions

The distributions of the partial pressure of carbon dioxide (pCO₂) and total alkalinity (TA) were examined for a 6-month period in the Wailuku and Wailoa rivers and coastal waters of Hilo Bay on the west coast of the Island of Hawaii, USA. Main results for the largest and turbulent Wailuku River show in the watershed an oversaturation in CO₂ with respect to atmospheric equilibrium and a CO₂ undersaturation in the estuary. In the Wailoa river-estuary system, extremely high pCO₂ values ranging from 1500 to 10500 ppm were measured with significant shifts in pCO₂ from drought to flood period. In the two rivers, water residence time, groundwater inputs and occasional flood events are the predominant drivers of the spatial and temporal patterns in the distribution of pCO₂. In Hilo Bay, CO₂ oversaturation dominates and the bay was a source of CO₂ to the atmosphere during the study period. TA is conservative along the salinity gradient, indicating calcification in the bay is not a significant source of CO₂ to the atmosphere.     

Medium-scale traveling ionospheric disturbances observed by GPS receiver network in Japan: a short review

Medium-scale traveling ionospheric disturbances (MSTID) are wave-like perturbations of the ionospheric plasma with wavelengths of several hundred kilometres and velocities of several hundred metres per second. MSTID is one of the most common ionospheric phenomena that generally induce the perturbations of ionospheric total electron content (TEC) by ∼10¹⁶ electron/m², which corresponds to ∼54 ns (16.2 cm) delay at GPS L1 signal. In the past decade, several new characteristics on MSTIDs have been revealed by the TEC observations using the dense GPS receiver network in Japan. In this paper, we provide a short review of these new observations and summarize the morphological characteristics of MSTIDs in Japan.     

质子磁力仪电源系统

蓄电池过充电和过放电是导致其损坏的主要原因。质子磁力仪电源系统向用户提供了防止过充电和欠充电的铅蓄电池浮充电源、避免过放电的终止放电报警器和恒流输出式地磁分量补偿电源。介绍了该电源系统的性能和特点,各部分电路的工作原理、调试方法及使用注意事项。认为,使用该电源系统,不但可降低蓄电池的容量配制,延长其使用寿命,而且避免了充电和分量补偿电流调节的繁琐操作。     

塔中117井储层烃包裹体研究及油气成藏史

将一个烃包裹体视为一个小小的“油气藏圈闭”。若已知油气藏烃组分,应用 PVTpro4.0油藏烃类流体相态平衡软件,可以获取油气藏圈闭的组分 PVT 相图及捕获压力参数。本文首先对 TZ117井盐水包裹体和烃包裹体进行观察分析,将TZ117烃包裹体分成三期,然后在-170℃条件下利用喇曼测定烃包裹体中烃组分的相对含量,并输入 PVTpr04.0油藏烃类流体相态平衡软件中做出烃包裹体 PVT 相图,确定烃包裹体捕获压力。根据烃包裹体捕获压力,恢复三期烃包裹体形成时的深度,结合 TZ117埋藏史,研究 TZ117井油气成藏史。     

ROCESSES OF EPHEMERAL GULLY EROSION

IINTRoDUCTIONEphemeralgulliesaresmallerosionalchannelsonagriculturalIandscapescausedbytheconcentrationofoverlandflowtypicallybetweentwoopposingslopes(ahollow),oftenformedduringasingIerainfaIlevent.Sincethescouredsoilvolumeisnotverylargewithinthesegullies,farmerscaneasilyrefillthem.Ingeneral,ephemeralgulliescanreappearatornearthesamelocationonayearlybasisbecausethesurfacetopograPhyofthefielddoesnotchangeappreciably.Mostephemeralgulliesoccuroncultivatedfieldswithhighlyerodiblesoils,withlit…     

SEDIMENT TRANSPORT PROCESSES IN AGRICULTURAL WATERSHEDS

lINTR0DUCTI0NTheerosion,transportanddep0siti0nofsedimentinawatershedarepallofthenaturalsystemofwatershedprocesses.InanundistUrbedwatershed,s0ilsinuplandareasaregraduallyeroded,transportCdforsomedistanceandeventuallydepositedatlowereIevations.WhenwatershedsaredistUrbedbyhumanactivitiessuchasclearingofvegetation,urbaniZati0n,orotherchangesthataffectthelandscaPe,unstablechannelswithlocallyhighratesoferosion,transport,0rdepositionofsedimentoftenaretheresult.Theimpact0fer0sionisespeciallyhigh…     

点状聚能射流侵彻岩石的超动态试验研究

为了揭示聚能爆炸射流切割和破碎岩石的内在一般规律 ,利用超动态应变试验测试了岩石在点状聚能射流作用下的受力情况。试验表明 ,岩石在聚能射流作用下 ,除射流直接作用处为射流冲击、高温融熔破坏外 ,其整体破坏以切向拉伸破坏为主。另外 ,炸高、岩石是否受约束均会对聚能射流侵彻岩石的效果产生显著影响。