隧洞冒顶陷落引发的滑坡灾害

兰州市区以崩塌、滑坡、泥石流为主的地质灾害非常发育,在诸多对地质灾害的影响因素中,降水是市区地质灾害最主要的引发因素。对兰州市区历史记载的山洪、地质灾害发生时的降水量进行分析,探讨兰州市区引发地质灾害的临界降水量,划定不同雨强时的地质灾害气象预警范围。     

山东商河地区地热井钻效分析

商河县地热井资源丰富,蕴藏量巨大,其热储含水层主要为新近系馆陶组以及古近系的东营组。通过区内施工的4个地热井的钻效分析,认为：①采用电动机作为动力的4#地热井施工工期明显优于其他3口采用柴油机作动力的;②本区构造较简单,断层稀少,分阶段使用PDC钻头可以将施工工期大大缩短;③泥浆泵的泵量达到或接近钻孔的环空最低上返速度时,可有效携带岩屑,建议泥浆岩屑上返速度不低于0．5m/s;④使用Ф127mm钻杆代替Ф89mm钻杆,可使钻杆的抗扭强度增加,保证施工的安全;⑤地面使用泥浆罐配备除泥器间断性除泥,保证泥浆液面高于泥浆泵阀室,泥浆靠自重流入泥浆泵阀室内,降低了泥浆泵从循环沉淀池抽吸功耗与节省吸人阀磨损。对比结果可为该区进行地热井施工提供借鉴。     

Simulation of non-stationary conditional ground motion fields in the time domain

This paper addresses the topic of simulating spatially variable ground motion fields conditioned on a known accelerogram. The conditional ground motion fields can be used in design or verification studies where seismic analysis has to be performed for a couple of natural accelerograms that have been preselected by seismologists or other experts. The methodology is based on conditional densities. In contrast to most authors, the conditional densities method is not applied to the Fourier coefficients, but it is used for the construction of a conditional Gaussian process model in the time domain. This has the advantage that fully non-stationary conditional time histories can be simulated directly in the time domain. The cross-correlation functions needed for this approach are evaluated from commonly used ground motion models expressed as evolutionary power spectral densities. An application to the El Centro earthquake record is presented. The properties of the simulated ground motion fields are analysed and compared to the data and the theoretical model.     

山东沿海风能资源分布特征及评估

利用山东省沿海测风塔70 m高度完整1 a的观测资料计算分析风能资源参数特征.结果表明：山东沿海地区平均风速与有效风功率密度分布特征相似,烟台沿海区域平均风速及有效风功率密度最大分别达到6.7 m/s、463.5 W/m²,沿海北部地区风能资源最为丰富,日照地区最少;受海陆风作用,春季风能资源最好,其次是冬季,夏季最差,风速最大值基本出现在14-16时;年有效风能时数及百分率分别为7 440 h、85%;风能密度分布基本以偏北或偏南方位较大.沿海区域风能资源分布特征与长年代评估结果及数值模拟结果基本一致.     

新一代天气雷达测试仪表使用解析

介绍新一代天气雷达功率计和示波器的基本操作方法、注意事项和衰减值的计算方法,以利于保证仪表安全和排除故障.     

Bias Correction in Wind Direction Forecasting Using the Circular-Circular Regression Method

Wind direction forecasting plays an important role in wind power prediction and air pollution management. Weather quantities such as temperature, precipitation, and wind speed are linear variables in which traditional model output statistics and bias correction methods are applied. However, wind direction is an angular variable; therefore, such traditional methods are ineffective for its evaluation. This paper proposes an effective bias correction technique for wind direction forecasting of turbine height from numerical weather prediction models, which is based on a circular-circular regression approach. The technique is applied to a 24-h forecast of 65-m wind directions observed at Yangmeishan wind farm, Yunnan Province, China, which consistently yields improvements in forecast performance parameters such as smaller absolute mean error and stronger similarity in wind rose diagram pattern.     

“Losing at Sea,Winning on Land”: A Case Study of Philippine Small-Scale and Industrial Fisher Resource Competition

In Southeast Asia, resource competition causes conflicts between small-scale and industrial fishers. This article focuses on interactions between small-scale and industrial fishers and the power dynamics that are expressed through their behaviors. Taking a Philippine fishing village as a case, this article shows that even under conditions of severe resource competition and in a context of antagonistic relationships, small-scale fishers may choose, as a survival strategy, to collaborate with illegal industrial fishers. It demonstrates that accounting for power differentiations and dynamics among actors is key to understanding this seemingly contradictory collaboration, one that will likely result, over the long run, in negative consequences for the sustainability of small-scale fishers’ livelihoods. In order to effectively control industrial fishers and mitigate conflict with small-scale fishers, better understanding of social–economic and sociopolitical relations is required.     

GPS时间序列中异常周期信号影响机制分析

采用功率谱分析和主成分分析的方法对GPS坐标时间序列的周期性变化进行了探讨,对IGS站的部分时段的观测资料进行了处理,分析了台站时间序列潜在的周期性质。证实了异常周期项（1．04cpy）的存在,对探测出的异常周期信号分别从构造信号、共模误差、地表质量负荷等影响因子展开讨论,分析其来源及影响机制。结果表明,上述影响因素未能对异常周期信号做出合理解释,该异常信号与GPS观测技术本身,即未模型化的GPS系统误差相关。对其影响因素做了初步探讨,为进一步建立相应的误差改正模型,增强GPS观测技术的稳健性提供了一些参考。     

空间域分割的机载LiDAR数据输电线快速提取

机载LiDAR具有快速、直接获取地物3维坐标的能力,在电网高压输电线路安全巡检中具有较大的应用前景。论文针对机载LiDAR输电线智能巡检的需求,提出并实现了一种基于空间域分割的LiDAR点云数据输电线自动提取方法。该方法首先利用高程直方图统计法去除地面点,再次利用点云密度差异剔除杆塔,根据相邻线之间的距离差和相邻层的高程差进行单根输电线分离。最后,采用多项式模型在3维空间中重构每根输电线空间坐标。实验结果表明该方法能够快速自动地提取多个杆塔之间的多根输电线数据,具有一定的工程应用价值。     

两种功率倒置阵列天线调零模型的等效性分析

在对卫星导航接收系统中两种常见的功率倒置阵列天线调零模型：基于参考信号的最小均方误差模型和线性约束条件下的最小功率模型,利用分块矩阵求逆特性从理论上证明了这两种模型之间的等效性,并针对不同模型的特点指出了这两种模型各自不同的应用场合,通过仿真对理论分析的有效性进行了验证,从而为卫星导航接收系统中的抗干扰调零天线的理论建模、仿真设计和实际应用提供了新的参考。