La classe des projections equidistantes dans les méridiens et dans les parallèles

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La fonction d'appui dans les formules de la géodésie mathématique

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Les formes différentielles extérieures dans la géodésie II: Courbure moyenne

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Some methods of adjusting a terrestrial spatial network (Part 1)

Summary In the Part 1 and in a subsequent Part 2 to be published two methods of adjusting a spatial terrestrial network in tri-dimensional space are described. Care has been taken that the nature of the equations used, as well as of the adjustment, correspond to the same in adjustment satellite networks. The adjustment was carried out by the least-squares method according to conditioned observations. Various types of condition equations have been constructed according to the various types of adjusted quantities, and the various alternatives of the introduced errors (changes of input values) and weights. An effort was made to eliminate the ellipsoid of reference to the largest extent. The theory was applied numerically to a model of a smaller network which corresponds in position and height to usual triangulation networks with side lengths of about 30 km.Dedicated to 90th Birthday of Professor Frantiek Fiala     

Impacts of Human Activities on Groundwater Quality of an Alluvial Aquifer: A Case Study of the Eskişehir Plain, Turkey

Hydrochemical and water-quality (except biological) data obtained through a two-year sampling and analysis program indicate that the highest concentrations of groundwater pollution occur in the central and eastern parts of Eski?ehir city. Groundwater quality degradation outside the urban area results from agricultural activities. The most serious pollution of groundwater in the Eski?ehir plain is from nitrogen compounds (ammonia, nitrite, and nitrate). The concentrations of ammonia, nitrite, and nitrate of the 51 surveyed water wells range from 0.01–1.65 mg/L, 0.01–1.80 mg/L, and 1.1–257.0 mg/L, respectively. Orthophosphate concentrations in groundwater range from 0.01–1.25 mg/L. Considerable seasonal fluctuation in the groundwater quality was observed. In general, the groundwater quality in wet seasons was better than the quality in dry seasons.     

圆扫描式机载激光测深系统检校模型及仿真分析

为了提升圆扫描式机载激光测深系统的定位精度,提出了一种检校思路:在平面区域获取激光点云时,系统误差和随机误差使得本应共面的激光点云不再共面,通过将激光点云拟合到单个平面上达到纠正点云位置的目的。首先推导了简单模式下圆扫描式机载激光测深系统定位模型,并从直线与平面交会的数学原理出发模拟激光光线与海面的交会过程,根据折射原理解算激光光线在水中的方向矢量,联合激光光线在水中的直线方程和海底面数学方程解算激光脚点的位置。然后,引入未知数先验方差,推导了参数加权最小二乘平差模型,为后面检校模型的解算奠定基础。最后,推导了用于检校的平差数学模型和详细的计算过程,对检校过程进行了模拟计算和分析讨论,得出了一些有益于检校过程的结论。     

湖南省毛湾矿区蚀变岩体型钨矿地球化学特征与成矿关系

毛湾矿区出露的岩体属川口岩体的一部分,岩性为二云母二长花岗岩,高硅、中碱,SiO_2和K_2O含量分别平均为74.72%和4.33%,Na_2O+K_2O平均为8.11%,K_2O/Na_2O平均为1.18%,Al_2O_3平均为13.28%,总体属过铝质钙碱性花岗岩类。Ba、Sr等元素表现为强烈的亏损,Mn表现为弱亏损;而Nb、Ta、Sb、W、Mo、Bi、Sn等相对富集,∑REE平均77.22×10~(-6),(La/Yb)N平均为2.67,LREE/HREE平均为2.92,δEu值平均为0.16,显示出岩体从早到晚具有中酸性向酸碱性演化的明显特征,轻重稀土比值有逐渐降低的趋势,表明其挥发组分含量由少到多的演化规律,对探索成矿花岗岩形成的物质来源、岩浆演化机制具有一定意义。     

Reliability‐based robust control for uncertain dynamical systems using feedback of incomplete noisy response measurements

A reliability‐based output feedback control methodology is presented for controlling the dynamic response of systems that are represented by linear state‐space models. The design criterion is based on a robust failure probability for the system. This criterion provides robustness for the controlled system by considering a probability distribution over a set of possible system models with a stochastic model of the excitation so that robust performance is expected. The control command signal can be calculated using incomplete response measurements at previous time steps without requiring state estimation. Examples of robust structural control using an active mass driver on a shear building model and on a benchmark structure are presented to illustrate the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.     

Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes

The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR–GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0–2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal \(-44.9, -35.0\), and \(-22.4\) mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear and angular velocities.     

Preliminary health risk assessment for polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins/furans in seafood from Guangzhou and Zhoushan, China

Dietary intake is one of the important routes of human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). The use of PBDEs may also result in exposure to polybrominated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs), as these compounds are impurities in technical mixtures of BFRs and can also be formed unintentionally by the same processes that generate chlorinated dioxins. This study determined the concentrations of polybrominated compounds in common seafood in Guangzhou and Zhoushan, and assessed the health risks of these chemicals via consumption of contaminated seafood. Seafood samples (fish, bivalves, shrimp, crab, and cephalopods) purchased from local markets in 2003 and 2004 were analyzed for PBDEs and PBDDs/DFs. The highest concentration of total PBDEs (46.3 ng g⁻¹ lipid wt.) was detected in fish from Guangzhou, in which BDEs 47 and 209 were the two predominant congeners. The total daily intakes of PBDEs, PBDDs, and PBDFs were, 946, 6.39, and 6.54 pg kg⁻¹ body weight (bw) in Guangzhou, and 489, 4.99, and 7.65 pg kg⁻¹ bw in Zhoushan, respectively. The hazard ratios for PBDDs and PBDFs were both greater than unity, indicating that these compounds may pose some health risks to the local population.