CT-1地震计传递函数测试仪的设计

将计算机控制技术应用到甚宽频带地震计的传递函数测试中。讨论了基本的测试方法和原理，阐述了传递函数测试系统的软、硬件设计，给出了测试系统的应用实例。该测试系统具有正弦波自动扫频、阶跃信号法和脉冲信号法等标定方法，满足了甚宽频带地震计的传递函数测试在观测频带、动态范围和测试精度等方面的要求。     

基于平均分组和叠加相关的GPS信号捕获方法

针对目前GPS软件接收机C/A码捕获信噪比门限高、捕获速度慢的问题,提出一种基于平均分组和叠加相关的GPS弱信号捕获方法。首先,基于平均相关处理技术降低C/A码捕获过程中的自相关损耗,提高对微弱信号的捕获能力;然后,利用叠加相关提高相干运算的运算效率,并采用线性插值提高自相关函数性能;最后,利用频偏校正和内插进一步提高C/A信号的捕获精度。理论分析和仿真实验均验证,该方法能够在较低的信噪比下实现GPS信号捕获,且精度较高、运算量较低。     

Comparison of radial basis function networks and empirical equations for converting from pan evaporation to reference evapotranspiration

Evapotranspiration (ET) is one of the major processes in the hydrological cycle, and its reliable estimation is essential to water resources management. Numerous equations have been developed for estimating ET, most of which are complex and require numerous items of weather data. In many areas, the necessary data are lacking, and simpler techniques are required. Evaporation pans are used throughout the world because of the simplicity of technique, low cost, and ease of application. In this study, the radial basis function (RBF) network is applied for pan evaporation to evapotranspiration conversions. The adaptive pan‐based RBF network was trained using daily Policoro data from 15 May 1981 to 23 December 1983. The RBF network obtained, Christiansen, FAO‐24 pan, and FAO‐56 Penman–Monteith equations were verified in comparison with lysimeter measurements of grass evapotranspiration using daily Policoro data from 25 February to 18 December 1984. Based on summary statistics, the RBF network ranked first with the lowest RMSE value (0·433 mm day^?1). The RBF network obtained on the basis of the daily data from Policoro, Italy and pan‐based equations were further tested using mean monthly data collected in Novi Sad, Serbia, and Kimberly, Idaho, USA. The overall results favoured use of the RBF network for pan evaporation to evapotranspiration conversions. The use of the RBF network is very simple and does not require any knowledge of ANNs. Users require only code (RBF network), E_pan data and corresponding R_a data. Copyright © 2009 John Wiley & Sons, Ltd.     

基于SaaS的区域非职业体育赛事云服务平台的设计与实现

与传统软件架构模式相比,云计算具有综合成本较低、部署快速、规模调整灵活等优势,针对区域非职业体育赛事在信息采集、组织管理、赛果处理与发布等赛事运营、组织、管理等方面存在的不足,从平台构建的可行性、架构与功能等方面,讨论并实现了一种基于SaaS模式的非职业体育赛事云服务平台,最后从使用效益等方面总结该平台对于提升区域非职业体育赛事组织与管理所取得的促进作用。     

基于SBAS/PS-InSAR技术的滑坡遥感监测对比研究

以2015~2019年12景ALOS-2 PALSAR2影像和2018~2019年38景Sentinel-1A影像为主要数据源,利用PS-InSAR和SBAS-InSAR技术提取西藏江达县波罗乡白格滑坡点的形变信息,并对处理结果进行交叉验证。研究得到以下结论：1）PS-InSAR技术条件下,ALOS-2数据和Sentinel-1A数据的平均形变速率范围为-68.9~37.9 mm/a和-64.5~24.2 mm/a;SBAS-InSAR技术条件下,ALOS-2数据和Sentinel-1A数据的平均形变速率范围为-84.2~-40.0 mm/a和-84.0~-13.0 mm/a。2）对2种数据结果中提取的4个特征点进行时序分析和定量分析显示,2种InSAR技术结果变化趋势较为一致,验证了两者在滑坡监测中的可靠性和准确性。     

不同城市规划的生态质量差异对比研究

为定量分析不同城市规划理念带来的生态质量差异,本文以福州市在不同时期规划建设的2座体育场馆为例,基于Sentinel-2A遥感影像,应用新型遥感生态指数RSEI分析对比了这2座体育场馆的生态效应。在全面分析其主要地表覆盖信息的基础上,探讨了二者之间生态质量差异的原因。研究发现,采用传统理念规划的福建省奥林匹克体育中心的生态指数RSEI均值为0.39,而实行绿色生态规划的海峡奥林匹克体育中心的RSEI均值为0.42,优于福建省奥林匹克体育中心。总的看来,海峡奥体中心在规划中采用透水铺装和不勾缝的铺装形式,加大绿地斑块面积以及预留风道等绿色措施有效地提高了地表湿度、降低了地表温度和干度,从而对该体育中心的生态质量起到积极的作用。     

虚拟太阳天文台及其发展

伴随着太阳物理研究的深入、观测仪器的发展、观测数据的积累,促使人们去思考这样一个问题:如何使研究者能够方便地检索、分析和使用在不同时间、不同地点、不同波段上观测得到的大量与太阳有关的数据,从而能探索更多悬而未决的科学谜题。这就是虚拟太阳天文台(VSO)项目被提出后得到有关天文台、研究所和大学积极响应并迅速投入运作的原因所在。介绍了虚拟太阳天文台的由来、作用、采用的技术和发展状况等。     

蓝离散星研究现状(Ⅰ):形成机制

大量研究表明,蓝离散星的形成可能有多种机制,目前比较流行的形成机制可以概括为以下几类:密近双星系统的质量传输及双星并合、密集星场的恒星碰撞,以及包含双星系统的恒星间 (双星-单星、双星-双星)相互作用导致的恒星并合。与此同时,蓝离散星在各类恒星系统中的普遍存在,也使得研究这类恒星的形成及演化成为追踪恒星系统动力学演化、化学演化及积分光谱性质变化的有效指针。     

蓝离散星研究现状(Ⅱ):观测特性

不同恒星系统(银河系晕、疏散星团、球状星团、矮星系)中蓝离散星所表现出的观测特性各不相同,这与恒星系统动力学环境及相应的蓝离散星主导形成机制直接相关。因此,分析研究蓝离散星的不同观测特性,也就成为研究蓝离散星形成机制、恒星及双星系统演化以及恒星系统动力学演化的有效方法。     

What is the closest black hole to the Sun?

We examine the distance of the two galactic microquasars GRO J1655–40 and A 0620–00 which are potentially the two closest black holes to the Sun. We aim to provide a picture as wide and complete as possible of the problem of measuring the distance of microquasars in our Galaxy. The purpose of this work is to fairly and critically review in great detail every distance method used for these two microquasars in order to show that the distances of probably all microquasars in our Galaxy are much more uncertain than currently admitted. Moreover, we show that many confirmations of quantitative results are often entangled and rely on very uncertain measurements. We also present a new determination of the maximum distance of GRO J1655–40 using red clump giant stars, and show that it confirms our earlier result of a distance less than 2 kpc instead of 3.2 kpc. Because, it then becomes more likely that GRO J1655–40 could originate from the stellar cluster NGC 6242, located at 1.0 kpc, we review the distance estimations of A 0620–00, which is so far the closest black hole with an average distance of about 1.0 kpc. We show that the distance methods used for A 0620–00 are also problematic. Finally, we present a new analysis of spectroscopic and astrometric archival data on this microquasar, and apply the maximum distance method of Foellmi et al. [Foellmi, C., Depagne, E., Dall, T.H., Mirabel, I.F., 2006b. A&A 457, 249]. It appears that A 0620–00 could indeed be even closer to the Sun than currently estimated, and consequently would be the closest known black hole to the Sun.