关于智能建筑中防雷设计的探讨

智能化建筑通信系统中各种电子器件,计算机和网络设施等,其特点是电子器件密度大,集成度高,因而它受雷电电磁脉冲袭击的危险性也大大增加,其后果可能使整个建筑内的通信系统的设备部分或全部损坏,数据丢失和运行失误,直至处于瘫痪。因此,如何能有效地避免雷电在通信系统中的破坏作用,是智能建筑设计中的一个重要环节。     

浅析智能建筑的内部防雷保护

随着社会经济的发展,近年来,智能建筑方兴未艾,已逐渐成为衡量城市建筑的现代化标准之一.智能建筑的弱电系统主要由以下各系统组成:     

不间断电源的原理、安装、使用和维护

随着科学技术的不断发展，各种电子设备特别是计算机的普及，对电源质量的要求越来越高。如电源突然中断，将导致通信中断，可能使计算机数据丢失、运行程序破坏，甚至磁盘和磁头损坏。电源电压过高过低、工频误差太大，都将影响工作的正常开展，危及设备的安全。随着工农业的不断发展，电网中各种用电设备的增加，设备间通过电网的干扰也日益增加，都可能引起一些设备的误动作，或者对接收设备造成干扰。不间断的供电，电压、频率稳定，尽量减少电网中的各种干扰，这是用电设备特别是计算机等电子设备对电网的基本要求，UPS不间断电源就…     

简易断电自动报警装置

计算机在运行期间,电源供电不能中断,否则降会导致数据丢失,严重时造成磁盘盘面和磁头损坏。虽然UPS不间断电源可以解决这一问题,但是UPS电源内部蓄电池的容量是有限的,当市电中断时,一般只能延时供电10～20分钟。在此期间,管理人员应及时对计算机内存中的程序或数据等进行存盘处理,然后关闭主机和UPS电源。在实际工作中,往往有的微机     

智能建筑电子信息系统防雷设计及施工应注意的几个问题

智能建筑以建筑物为平台,兼备通信、办公、设备自动化,系统服务、管理及它们之间的最优组合,并向人们提供一个安全高效、舒适、便利的建筑环境.其最大特点是建筑环境内部配备了大量的电子信息系统.     

智能建筑接地技术探讨

随着经济的快速发展,大量的智能建筑拔地而起,其内部包含大量的电子设备,这些设备的耐压等级低、抗干扰性能差,因此在智能建筑的设计施工中,不但要重视智能建筑的性能指标和设备的先进性,更应注意接地技术的应用。接地对于智能建筑中设备的安全运行和数据的可靠传输具有重要影响,并且是抑制电磁干扰、提高电子设备电磁兼容性的重要手段之一。

     

计算机机房避雷器安装及常见问题处理

1电源及信号避雷器安装电源避雷器是多用并联型的,如图1所示(T为避雷器,下同)。对于大型机房,我们作3级防护(实际中所谓3级防护是针对计算机设备而言,而对于照明、空调线路我们只作2级防护)。第1级在总电源的输入端,既可在总配电房,也可在楼层总电源处,一般为380V。第2级紧随其后,在各分电源线路上的设备前,一般为220V。第3级在UPS前端。这是我们遵循的一般原则,也是与规范吻合的。而对中、小型类机房,可根据规范作相应的调整。至于接线方法及工艺问题,有技术规范要求也有主观因素,也与具体产品有关,需从外观和质量两方面…     

智能建筑接地技术探讨

随着经济的快速发展,大量的智能建筑拔地而起,其内部包含大量的电子设备,这些设备的耐压等级低、抗干扰性能差,因此在智能建筑的设计施工中,不但要重视智能建筑的性能指标和设备的先进性,更应注意接地技术的应用。接地对于智能建筑中设备的安全运行和数据的可靠传输具有重要影响,并且是抑制电磁干扰、提高电子设备电磁兼容性的重要手段之一。建筑物供配电设计中,接地系统设计占重要的地位,它关系到供电系统的可靠性、安全性。1供配电接地系统的几种形式1.1 TN-S系统TN-S是三相四线加PE线的接地系统(图1)。建筑物设有独立变配电所时进线…     

ATX电源代换AT电源的方法

ATX电源和 AT电源两种不同标准的微机电源 ,由于 AT电源已逐渐淡出市场 ,新的 AT电源已很难买到。通过对 ATX电源与 AT电源的主要区别分析 ,找出 ATX电源代换 AT电源以解决 AT电源损坏后无件可换的问题。     

自动气象站系统的日常维护方法

介绍了自动气象站系统中各种传感器、采集器、通讯线路、电源系统、计算机等硬件在日常维护中的维护方法.     

加强业务管理提高测报质量

我局从1999～2003年,测报工作连续4年未出现错情,在此期间共有1个250个班,9个百班无错通过上级业务部门验收.在仪器保管、使用、维护上符合要求,对外报送的各种表、簿都能做好出门合格.     

Comparing the theoretical versions of the Beaufort scale, the T-Scale and the Fujita scale

2005 is the bicentenary of the Beaufort Scale and its wind-speed codes: the marine version in 1805 and the land version later. In the 1920s when anemometers had come into general use, the Beaufort Scale was quantified by a formula based on experiment. In the early 1970s two tornado wind-speed scales were proposed: (1) an International T-Scale based on the Beaufort Scale; and (2) Fujita's damage scale developed for North America. The International Beaufort Scale and the T-Scale share a common root in having an integral theoretical relationship with an established scientific basis, whereas Fujita's Scale introduces criteria that make its intensities non-integral with Beaufort. Forces on the T-Scale, where T stands for Tornado force, span the range 0 to 10 which is highly useful world wide. The shorter range of Fujita's Scale (0 to 5) is acceptable for American use but less convenient elsewhere. To illustrate the simplicity of the decimal T-Scale, mean hurricane wind speed of Beaufort 12 is T2 on the T-Scale but F1.121 on the F-Scale; while a tornado wind speed of T9 (= B26) becomes F4.761. However, the three wind scales can be uni-fied by either making F-Scale numbers exactly half the magnitude of T-Scale numbers [i.e. F′half = T / 2 = (B / 4) − 4] or by doubling the numbers of this revised version to give integral equivalence with the T-Scale. The result is a decimal formula F′double = T = (B / 2) − 4 named the TF-Scale where TF stands for Tornado Force. This harmonious 10-digit scale has all the criteria needed for world-wide practical effectiveness.     

准两年振荡对大气中微量气体分布的影响

NCAR的包含化学、辐射、动力相互作用的两维模式（SOCRATES）移植回国后进行了初步的模拟试验,用以研究某些对环境问题重要的微量气体的化学、辐射、动力传输过程。在不考虑极地平流层云和气溶胶表面非均相化学等情况下,模式积分多年,计算结果稳定,模拟的风场、温度场显示出正常的季节变化,模拟的微量气体分布与卫星实测资料对照,结果也比较一致。为了探讨热带平流层风场的准两年周期振荡（QBO）对平流层微量气体分布的影响,我们做了QBO强迫的数值试验,即在模式中加入QBO强迫,并与不考虑QBO强迫的模拟结果对比。结果表明,QBO与其相关的次级环流所引起动力输送的变化,使平流层微量气体分布发生变化。     

Quantifying the uncertainty of the annular mode time scale and the role of the stratosphere

The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998–2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.     

由中国历史气候记录对季风导致唐朝灭亡说的质疑

2007年1月4日杂志发表了Yancheva等10人的题为"Influence of the intertropical convergence zone on the East-Asian monsoon"(热带辐合带对东亚季风的影响)的论文[1],这是德国波兹坦地学研究中心气候动力与沉积学科的主管豪格(G.H.Haug)率领的科研小组的一项成果,认为是季风的变化引起的长期干旱导致了唐朝的灭亡.     

流场配置及地形对西南低涡形成的动力作用

本文采用定常二层模式讨论较小地形及高、低层流场配置对西南低涡形成的动力作用。指出了西南低涡的形成是与盆地、河谷以及其上气流分层有关的一种定常态.在上、下为西风分层时期,低层的浅薄暖湿西风有利于西南低涡的形成.在上、下为东、西风分层时期,上层浅薄东风亦有利于西南低涡的形成.小型的凸起山脉对西南低涡的形成没有作用.     

On the forecast of the onset and end of the convective season in the Amazon

Summary ?Some features of the climate system that can be considered predictors of the onset and end of the convective season over the Amazon were identified using one-month lag correlations and field composites. The fields analyzed were sea surface temperature (SST), outgoing long-wave radiation (OLR), vertical velocity and upper tropospheric winds. Warm (cold) anomalies in the SST in the tropical North Atlantic and the Caribbean Sea tend to be associated with delayed (early) onsets. Likewise, there is a tendency towards a delayed (early) end of the convective season with cold (warm) anomalies in these ocean regions. In addition, the SST in the cold tongue region of the equatorial Pacific is negatively, though weakly correlated with the onset date. The signal of this SST is more evident in the case of the end date, which is earlier with respect to its mean date in most of El Ni?o cases. The convective activity intensity itself conditions the onset and the end of the convective season, as it is evidenced by the behavior of the OLR and the vertical velocity fields. The more (less) intense the convective activity over South America during the preceding month, the earlier the onset and the later the end of the convective season on the Amazon region. The prediction of the onset and end dates of the convective season in the Amazon region was explored using a simple multiple regression technique based on the variables that have shown precursor signals with respect to these dates. The correlation coefficient between the predicted and the observed onset date is 0.81, and in the case of the end date, it is 0.76. The skill to predict early, delayed and normal categories was high, since in more than two thirds of the cases the category was successfully predicted, and there were no predictions of categories opposed to those observed. Received July 23, 2001; revised February 22, 2002; accepted April 26, 2002     

Analysis of the Characteristics of the Low-level Jets in the Middle Reaches of the Yangtze River during the Mei-yu Season

Here, we analyze the characteristics and the formation mechanisms of low-level jets(LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts(ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets(BLJs) concentrated at heights of 900–1200 m.The BLJs occur most frequently at 230...