A comparison of ionosonde measured foF2 and IRI-2016 predictions over China

A comparison of the ionospheric F-region critical frequency (foF2) between ionosonde measurements and IRI-2016 predictions is studied over China during the period from January 2008 to October 2016. Four stations are selected, and the latitude coverage starts at 49.4°N and ends at 23.2°N with a sequential latitude interval of about 10°, the corresponding geomagnetic latitudes are from 39.5°N to 13.2°N. The results show that the variability of the observed foF2 versus latitudes, seasons, local time and levels of solar activity could be well reproduced by IRI-2016. However, the daily lowest value of foF2 from the IRI-2016 prediction occurs earlier than that from the ionosonde. Around the sunrise, the IRI-2016 prediction shows a very sharp rise and grows much faster than the observed foF2 in every month. The foF2 difference between the two options (URSI and CCIR) in IRI-2016 increases as the F10.7 index decreases. During 2008–2009, the annual average deviations of URSI and CCIR range from ?5% to ?10% and from 5% to ?5%, respectively. Generally, the CCIR performs better than URSI during postsunset under low solar activity or in Equatorial Ionization Anomaly (EIA) region over China, while it shows no large difference in performance with URSI in other locations or for other time.     

民航华北空管局设备管理综合数据库系统的建设

本文通过对华北空管局设备管理现状和信息化技术的深入研究探讨，详细阐述了构建华北空管局设备管理综合数据库系统的关键技术和框架结构。     

XPDM型露点仪在医用氧气分析中的应用

介绍了XPDM型露点仪的工作原理、仪器结构、技术指标、操作方法等.     

基于局域网的智能家庭网关

为了实现小区的智能化管理，以提高小区管理人员的工作效率和管理水平及小区居民的生活质量，提出了一种基于嵌入式网关的智能家庭网关，采用智能家庭网关并结合以太网技术而构建的小区智能管理系统，实现了对小区家庭的防火、防盗、煤气泄漏、紧急求助报警，水电气三表远程自动抄收，家电远程控制等功能。是真正意义上的网络化、智能化的家庭控制系统。     

Short-term forecasting regional model to predict M(3000)F2 over the European sector: Comparisons with the IRI model during moderate,disturbed, and very disturbed geomagnetic conditions

The hourly measurements of M(3000)F2 (M(3000)F2_meas) and the hourly quiet-time values of M(3000)F2 (M(3000)F2_QT) relative to the ionospheric observatories of Poitiers, Lannion, Dourbes, Slough, Rome, Juliusruh, Kaliningrad, Uppsala, Lyckesele, Sodankyla, and Kiruna as well as the hourly time-weighted accumulation series derived from the geomagnetic planetary index ap (ap(τ)), were considered during the period January 1957–December 2003 and used for the development of 11 short-term forecasting local models (STFLM) of M(3000)F2.     

An Investigation of Near-Equatorial Geomagnetic Pi2 Pulsations

There is understanding to date that Pi2 pulsations have two sources. One source is a high-latitude one and is due to fluctuations of electrojet parameters. The other source is a mid-latitude one and is driven by a global mode excited in the Earths plasmasphere. There is experimental evidence that in the near-equatorial regions the character of Pi2 excitation is different from high and mid-latitudes. In this connection, we investigated the amplitude-spectral-polarization characteristics of Pi2 pulsations using the date from near-equatorial Chinese stations. The detected regularities in the excitation of near-equatorial Pi2 pulsations are used in the discussion of the possible physical mechanism that is responsible for the generation of these pulsations.     

The equatorial ionization anomaly at the topside F region of the ionosphere along 75°E

Electron density measured by the Indian satellite SROSS C2 at the altitude of ∼500 km in the 75°E longitude sector for the ascending half of the solar cycle 22 from 1995 to 1999 are used to study the position and density of the equatorial ionization anomaly (EIA). Results show that the latitudinal position and peak electron density of the EIA crest and crest to trough ratios of the anomaly during the 10:00–14:00 LT period vary with season and from one year to another. Both EIA crest position and density are found to be asymmetric about the magnetic equator and the asymmetry depends on season as well as the year of observation, i.e., solar activity. The latitudinal position of the crest of the EIA and the crest density bears good positive correlation with F_10.7 and the strength of the equatorial electrojet (EEJ).     

钛基稀土激光熔覆层组织细化机制及性能

采用通快TruDisk 4002光纤激光器在TC4合金表面分别制备了0wt% Y₂O₃和3wt% Y₂O₃的TC4+Ni45+Co-WC钛基耐磨复合涂层。利用XRD、SEM、EDS、EPMA、显微硬度计和摩擦磨损试验机等分析了涂层组织、显微硬度和摩擦学性能。结果表明，两种涂层表面均无裂纹孔隙等缺陷，且生成相一致，主要包括TiC、TiB₂、Ti₂Ni、WC和α-Ti；0wt% Y₂O₃涂层组织存在明显偏析，析出相尺寸粗大且方向性明显；3wt% Y₂O₃涂层组织呈均匀弥散状态分布，细化特征明显；经Bramfitt二维点阵错配度计算，（100）_Y2O3和（100）_Ti2Ni、（111）_Y2O3和（110）_TiC、（110）_Y2O3和（1010）_TiB2间的错配度分别为5.75%、6.72%和10.10%，Y₂O₃作为异质形核核心对Ti₂Ni、TiC和TiB₂的细化能力依次为Ti₂Ni > TiC > TiB₂；0wt% Y₂O₃和3wt% Y₂O₃涂层显微硬度分别为600~630 HV_0.5和470~480 HV_0.5，较基材分别提高了约62%和26%；3wt% Y₂O₃涂层耐磨减摩性最优，其磨损体积和摩擦系数较0wt% Y₂O₃涂层分别下降了约47.8%和5.0%，磨损机制主要为磨粒磨损。     

基于深度学习的ADS-B异常数据检测模型

广播式自动相关监视（ADS-B）是下一代空中交通运输系统的重要组成部分，是新航行系统中非常重要的通信和监视技术，但其协议没有提供相关的信息认证和数据加密，因此极其容易受到欺骗干扰的影响。针对ADS-B报文数据特点，采用深度学习的seq2seq模型对ADS-B报文数据进行重构，通过重构误差来检测异常，并对数据进行特征扩展，使模型能更好的捕捉数据的时间依赖性。实验结果表明，所采用的方法优于传统的机器学习方法，且在数据特征扩展后，模型检测效果提升。相比于现有的欺骗干扰检测方法，该方法不需要改变ADS-B系统的协议，也不需要额外的节点或传感器参与，具有一定的适应性和灵活性。