原子荧光光谱法测定区域地球化学调查样品中硒的干扰校正

氢化物发生-原子荧光光谱法(HG-AFS)是测定土壤样品中硒(Se)的理想方法，常用SePb合金材质的空心阴极灯为激发光源，无色散系统的AFS测硒时存在铅的光谱干扰，但尚未引起广泛关注。本文研究了高浓度Pb对硒测定的影响，并提出一种干扰校正的方法，可对检测结果进行有效校正。同时对还原剂浓度和消解酸的比例进行了优化，在2~40 ng/mL范围内获得Se标准曲线r2=0.9989，检出限为0.0023 ug/g，方法精密度为2.9-9.8%，准确度ΔlogC小于0.035。对南疆铁门关区域地球化学调查样品进行了测定，校正后Se的检测结果合格率为94.0%。此方法具有操作简单、准确高效，能够有效的校正样品中高浓度Pb的干扰，适合于大批量区域地球化学调查样品的检测。     

Analysis of fluctuations of antenna pattern in U-V2X communications

The third-generation partnership project (3GPP) defined several scenarios of vehicle-to-everything (V2X) networks such as vehicle-to-vehicle, vehicle-to-pedestrian, and vehicle-to-infrastructure. Unmanned aerial vehicles (UAVs) exploiting such scenarios for vehicular applications like vehicular-platooning, autonomous driving, and traffic management have shown improved networks’ performance in UAV-V2X (U-V2X) communications. This promising performance is typically obtained by considering high directional UAV antennas. However, the UAV vibration makes UAV antennas’ beam-width sensitive to UAV fluctuations which results in degrading the networks’ performance. Thus, in this paper, the performance of a U-V2X network in the presence of UAV fluctuations is investigated. The UAVs are modeled using an independent homogeneous Poisson Point Process and the vehicular-nodes are modeled using an independent Poisson Line Process. To this end, the association probability and success probability of various links such as vehicular-node connected to a UAV link, vehicular-node connected to a near-by vehicular-node link, and the overall U-V2X link are derived. In addition, the effect of different network settings such as the number of vehicular-nodes, UAVs, roads, and antennas is quantified. Moreover, the spectral efficiency of a U-V2X network is evaluated. Extensive simulations revealed that V2X networks facilitate UAVs and that for less dense areas with fewer roads, buildings, and crowds; UAVs provide more reliable links for connectivity than vehicular-nodes. Furthermore, it is also revealed that UAVs provide less reliable connection for V2X networks with larger UAV antenna fluctuations.     

地震波作用下埋地管道截面应力偏移效应研究

PE管广泛应用于城镇燃气、水和浆体等输送领域，地震灾害下埋地管道易发生失效。为此，提出了一种地震波作用下埋地PE管-土耦合数值建模方法，研究PE管力学特性，探究管道内压、地震烈度、围土和覆土厚度等对其力学响应影响规律。结果表明，地震波作用下管道截面应力出现偏移效应，而非0°,90°,180°和270°位置；内压作用下管壁应力增加；管道环向应力随着地震烈度增加而增大，且应力偏移效应更加显著。研究结果可为PE管道敷设和安全评价等提供理论依据。     

基体匹配—电感耦合等离子体质谱(ICP-MS)法测定萤石精矿中痕量有害元素

为向萤石精矿质量检测和环境监管提供可靠的数据支撑，采用基体匹配—电感耦合等离子质谱法测试萤石精矿中痕量有害元素铜、锌、砷、镉和铅的含量。利用硝酸溶解分析纯碳酸钙后，经ICP-MS测试溶液中钙元素含量与理论值偏差约6%。钙溶液经不同倍率稀释后配置基体浓度为1000、2000和5000mg/L多元素标准溶液，在ICP-MS测试不同基体浓度混合标准溶液的内标回收率稳定性和IF/BK压降情况后，确定了1000 mg/L的最佳基体浓度。在传统四酸消解法基础上，通过改变加酸顺序、用量和温控水平，实现对萤石精矿的完全消解。消解实验中，同步设置消解加标、过程空白和空白加标实验。萤石精矿在消解定容及适度稀释后，溶液中离子浓度与复杂基体标准溶液的最佳基体浓度接近。在复杂基体标准溶液及样品消解液测试中，采用He模式的碰撞反应池技术，选用72Ge、115In和175Lu作为内标元素。结果显示：各元素标准曲线线性大于0.9995，各样品内标回收率在80%-110%范围波动，表明基体匹配联合内标校正，有效消除了复杂样品测试中的非质谱和质谱干扰。消解实验中未产生过量的元素沉淀或挥发损失，加标样品各有害元素回收率在90%-120%。质控样品各元素含量测试误差在15%以内。此测试方法中铜、锌、砷、镉和铅的检出限分别为4.81、8.65、17.91、0.49和2.84 μg/L，可满足复杂基体样品中痕量元素含量的准确测试需求。