Satellite and ground detection of very dense smoke clouds produced on the islands of the Paraná river delta that affected a large region in Central Argentina

Intense fires were produced on the Paraná river delta islands, Argentina, during most part of 2008, by a combination of an exceptionally dry period and the farmers’ use of a fire land-cleaning technique. In April 2008, those fires significantly affected the nearby regions and their inhabitants, from Rosario city to Buenos Aires mega-city. In this work we present satellite as well as ground Aerosol Optical Depth (AOD) at 550 nm data obtained during the propagation of pollution clouds to the central zone of Argentina. The highest value (1.18) was registered at Buenos Aires by atmospheric remote sensing, using the satellite instrument MODIS/Terra on April 18th 2008 at 10:35 local time (= UT − 3 h). On the same day, ground air quality detectors also measured in this city the highest Total Suspended Particle (TSP) value of the month, 2.02 mg/m³. The AOD(550) daily variation at Rosario Astronomical Observatory, which is located near the Paraná riverside, was derived by combining solar ultraviolet erythemal irradiance data (measured with a YES biometre) with model calculations. On April 25th 2008, from 12:00 to 15:30 local time, a rather high and constant AOD(550) value was registered, with a mean value of (0.90 ± 0.21). Cities located on the side of the Rosario–Buenos Aires highway (San Nicolás, Baradero and San Pedro) were also affected, showing a mean AOD(550) between the Rosario and Buenos Aires values. The particulate matter was collected with gridded samplers placed on the Paraná river islands as well as at the Rosario Observatory. They were analysed with a Scanning Electron Microscope (SEM) and mainly showed a biological origin. Even if normally large particles travel small distances from the source, organic aerosol in the range of 40–100 μm and complex asymmetric structures were registered several kilometres away from the aerosol sources on the islands. Another event of intense UV index attenuation (98.6%) occurred on September 18th 2008, due to very dense smoke clouds that extended over the Rosario area for several hours. The clouds were driven away from the fires by East–northeast and East–southeast winds. The minimum value of this index measured around noon allows to derive a maximum AOD(550)_max = (3.65 ± 0.90) at 12:45 local time. Soot clouds extended over the Paraná river, transporting Burned Biomass Debris (BBD) that deposited on Rosario. In particular, burned leaves and small branches with dimensions of 1–20 cm were collected. The mean (BBD) particles deposited on the ground from 7:00 to 19:00 local time were (0.92 ± 0.20) BBD/(m² h).     

气固两相透平叶片冲蚀特性的气动试验研究

在自行研制风洞中先后对应用较广的MCrAlY叶片涂层和2Cr12Mo-5叶片合金、钢丸表面强化试件在不同气流速度、颗粒冲角、颗粒性状、颗粒粒度的条件下进行了气动冲蚀试验。试验结果表明,无论是涂层还是合金,冲蚀率均随冲蚀颗粒的累积质量呈线性变化;由对比可知,其它条件相同的情况下,涂层在广泛的冲角范围内较合金的冲蚀率更小,表面的"烧结"特征,能减小叶片的冲蚀率;表面呈多棱的石英砂颗粒对试件的冲蚀程度强于带突圆球状的催化剂颗粒;在该试验范围内,相同材质的颗粒,粒度愈大,对试件的冲蚀率愈大;钢丸表面强化工艺兼有防冲蚀的能力。试验结果将为优化叶片选材、简化叶片维修技术、降低叶片维修成本提供有益的参考。     

民用飞机技术出版物规范应用

技术出版物作为民用飞机产品的重要组成部分,用于指导运营人正确地操作和维护飞机.为了满足相关适航规章的要求和用户对于交互式电子技术手册日益增长的需求,实现手册全寿命周期管理,飞机制造商应在保证手册完整、正确、准确的基础上,进一步实现手册的标准化、规范化和结构化.本文对国际主流技术出版物规范的特点、规范的确定、应用方法和风险等进行了介绍和阐述.     

Data fusion algorithm based on state and attribute parameter

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Comparison of decision tree methods for finding active objects

The automated classification of objects from large catalogs or survey projects is an important task in many astronomical surveys. Faced with various classification algorithms, astronomers should select the method according to their requirements. Here we describe several kinds of decision trees for finding active objects by multi-wavelength data, such as REPTree, Random Tree, Decision Stump, Random Forest, J48, NBTree, AdTree. All decision tree approaches investigated are in the WEKA package. The classification performance of the methods is presented. In the process of classification by decision tree methods, the classification rules are easily obtained, moreover these rules are clear and easy to understand for astronomers. As a result, astronomers are inclined to prefer and apply them, thus know which attributes are important to discriminate celestial objects. The experimental results show that when various decision trees are applied in discriminating active objects (quasars, BL Lac objects and active galaxies) from non-active objects (stars and galaxies), ADTree is the best only in terms of accuracy, Decision Stump is the best only considering speed, J48 is the optimal choice considering both accuracy and speed.     

SQL Server数据复制在自来水数据库系统中的实现

介绍了Microson SQL Server数据复制的概念、工作原理和拓扑结构,并结合自来水公司的业务特点和应用需求,提出了适合企业业务发展的分布式系统解决方案.     

高性能飞行器大气数据传感技术研究进展

大气数据是飞行器导航和控制的重要参数，大气数据传感技术是实现飞行器飞行安全及性能发挥的重要保障。针对高性能飞行器对大气数据传感技术的发展需求进行分析，重点介绍了传统大气数据传感技术、嵌入式大气数据传感技术、光学大气数据传感技术及虚拟大气数据传感技术的发展和特点，并对推动嵌入式大气数据传感技术发展的相关技术问题进行了分析和总结，最后对大气数据传感技术的发展进行展望。     

余度数据总线电气隔离度的测试与分析

"余度数据总线电气隔离度测试"是检验在数据总线和余度电缆之间存在电气耦合度的大小.通过对数据总线屏蔽层在接地与不接地状态下的电气隔离度测试,分析了"有传输活动"电缆对"无传输活动"电缆干扰的特征,阐述了电缆屏蔽层的良好接地是确保余度数据总线电气隔离度满足要求的关键.     

弹道跟踪数据野值剔除方法性能分析

弹道跟踪数据中的野值会影响导弹目标定位精度。对用于弹道跟踪数据的野值剔除方法进行了综述。结合事后和实时两大类处理模式,分析了各野值剔除方法在理论和工程应用上的优缺点,给出了实际应用时的限制因素,建立了野值判决准则和相应的野值剔除实现步骤。仿真结果表明:野值剔除方法可以有效提高弹道跟踪数据的精度。事后处理模式中,基于格拉布斯准则的野值剔除效果最佳;实时处理模式中,基于自适应门限的五点线性预报法野值剔除效果相对较好,且时间复杂度相对较低,适合实时处理。     

提高长线传输数字波形质量的技术措施

从两方面论述数字编码波形在长线上传输的影响因素及其改善措施。通过分析并经实验表明，长线的分布电容影响通常居诸因素之首位。改进长线驱动电路，在一定程度上，可改善其传输波形之质量。另外，可利用长线传输波形的同时，还传输供总线接口电路需要的电源能量，满足总线浮空隔离的要求，有效地抑制了共模干扰。此项技术适用于远距多路串行总线的数据采集系统。