地磁感应电流对我国电网影响的初步分析

对于地磁感应电流（GIC）对电力系统的有害影响，国外进行过大量的研究，但国内研究不够广泛。随着我国西电东送、全国联网战略的逐步实施．将要形成大量东西走向的超高压、大容量、远距离输电线路。我国部分地区地理位置和地质结构与受到过GIC影响的一些国家相似，我国电网是否存在GIC影响问题需要进行研究。在给出电网GIC机理．特征的基础上．通过对磁暴影响实例和我国电网综合情况分析得出初步结论．指出研究我国电网GIC影响的必要性，并就相关问题提出建议。     

浅议堤防的维护与度汛抢险措施

介绍了堤防的过量沉降、裂缝的处理方法，在汛期防止堤防漫顶、防风浪及工程实践中防滑坡的处理措施。     

山区输水管道工程的设计要点及陡坡直埋工艺

简要介绍了山区输水管道设计中常用的管道线路、管道材质、敷设方式、防冻方式及选取原则,重点介绍了一种适应山体陡坡段输水管直埋敷设的工艺。以供相关工程设计及施工人员借鉴。     

Prediction model of time diversity using Japan rain radar data

The effects of rain attenuation on communication systems will become more pronounced in future satellite communication systems, especially with the planned use of the 21‐GHz band or higher‐frequency bands. Diversity techniques provide a solution to mitigate rain attenuation effects. This study proposes a time diversity technique, one such technique that is likely to demonstrate high effectiveness. To model the system, rainfall rate statistics are necessary, and reliability is improved as the amount of statistical data increases. This paper derives the cumulative distribution of the rainfall rate across Japan over 4 years using rain radar data from the automated meteorological data acquisition system and ground‐based rain radar network and evaluates the rainfall rate at 23 observation points across Japan. We carry out a performance evaluation for all locations within Japan to confirm the efficiency of the time diversity method. Finally, we propose prediction model of the time diversity gain for Japan and other significant parameter which is time correlation of rainfall rate that was found from the time diversity results for further investigation. Copyright © 2016 John Wiley & Sons, Ltd.     

SJ型虹吸式雨量计的日常维护及常见故障排除

文章阐述了SJ型虹吸式雨量计的结构和工作原理;介绍了日常使用中的维护和保养方法;对仪器的常见故障现象进行了详细地分析,并给出了相应的处理方法。     

Trade‐Offs in Seed Dispersal Strategies Across Riparian Trees: The How Matters as Much as the When

Riparian Salicaceae are prolific producers of short‐lived seeds that require very restrictive hydro‐geomorphic conditions for establishment. It is generally assumed that if floods are able to create nursery sites timed with seed dispersal, recruitment will occur. Other spatial and temporal seed dispersal patterns besides the dispersal period have historically received little attention. However, seed dispersal patterns can be highly variable between regions, species and over the years. In this paper, we report the seed dispersal patterns of three dominant riparian Salicaceae trees in Europe: Populus alba, P. nigra and Salix alba to suggest possible trade‐offs between seed dispersal patterns, germinability, longevity and establishment. Seed rain of the three species was monitored in 33 glue‐coated traps for three months yearly from 2006 to 2008 in an 8‐km stretch of the Middle Ebro River (N Spain), which has a pluvio‐nival regime. P. alba dispersed seeds earlier during a shorter time period and with a fewer number of seed release pulses compared with P. nigra, and especially with S. alba. With overlapping seed dispersal periods, the two latter species occupy similar landform units but rarely compete with P. alba, usually at higher elevations, as shown in a previous study in the same study area. The three species had very high germinability immediately after release (>90%), but longevity in S. alba was eight times shorter than that of its two Populus counterparts. We suggest that S. alba has compensated its lower seed quality with a more spaced seed release in several pulses of similar magnitude. With similar seed dispersal patterns and germinability but a higher longevity, P. nigra had a much higher density of individuals than S. alba in the recruitment zones of the study area. We hope that our results may inform river managers about how to optimize river flows to promote sexual regeneration of these species. Copyright © 2015 John Wiley & Sons, Ltd.     

计及微振磨损与风雨荷载的输电线可靠性建模

输电线长期受风导致的振动引起股线间微振磨损,而外部强风雨荷载的冲击进一步加剧了磨损程度,导致断股、断线事故风险显著增加,因此对经受长期微振磨损的输电线在强风雨荷载冲击下的可靠性模型进行研究具有重要实用价值。基于微振磨损的理论模型建立了ACSR的结构强度时变模型,在考虑微振磨损的基础上计入强风雨荷载的影响,结合输电线强度和永久荷载的随机特性,建立输电线时间相依可靠性模型。所提时间相依故障概率模型可以对输电线断股、断线风险进行准确预测并实现恶劣天气下的输电线风险预警。算例结果表明,微振磨损会显著降低输电线的结构可靠性,而强风雨条件下的雨荷载则进一步加剧了事故风险。     

Application of computational fluid dynamics in building performance simulation for the outdoor environment: an overview

This article provides an overview of the application of computational fluid dynamics (CFD) in building performance simulation for the outdoor environment, focused on four topics: (1) pedestrian wind environment around buildings, (2) wind-driven rain on building facades, (3) convective heat transfer coefficients at exterior building surfaces and (4) air pollutant dispersion around buildings. For each topic, its background, the need for CFD, an overview of some past CFD studies, a discussion about accuracy and some perspectives for practical application are provided. This article indicates that for all four topics, CFD offers considerable advantages compared with wind tunnel modelling or (semi-)empirical formulae because it can provide detailed whole-flow field data under fully controlled conditions and without similarity constraints. The main limitations are the deficiencies of steady Reynolds-averaged Navier–Stokes modelling, the increased complexity and computational expense of large eddy simulation and the requirement of systematic and time-consuming CFD solution verification and validation studies.     

TCYII 1型酸雨自动观测系统校准与故障处理

TCYII 1型酸雨自动观测系统以AMR-A型户外全自动一体化分析仪为核心,该系统在自动采集降水的同时,能够自动测量样品的pH、EC和温度指标,还能扩展测量降雨点的大气参数。系统可通过网络完成自检和校准,并利用状态数据进行监控报警,对于推进地面观测业务无人值守具有重要意义。文章介绍了系统的组成和原理,阐明了系统校准和故障诊断处理方法,期望从观测源头对数据质量进行控制,保障酸雨观测数据的及时可靠。