类星体的中红外光谱分析(英文)     

谢艳霞  商朝晖 《天文研究与技术》2011,(3)

分析了42个类星体的SPITZER IRS中红外光谱,并测量了连续谱和各发射特征强度,其中包括5.5μm连续谱强度、10μm silicate发射,和窄发射线[S IV]10.5μm,[Ne V]14.3μm,[NeIII]15.6μm,和[O IV]25.9μm的流量。5.5μm连续谱强度和窄发射线强度之间存在很强的相关关系,说明5.5μm连续谱也由活动星系核中心光子直接激发,并可以作为活动星系核强度的示踪。发现10μm silicate发射与Eigenvector I没有相关关系,说明类星体中大多数的尘埃不可能与窄线区共存。  相似文献   

FAST无线式索力传感器节点的设计制作与测试     

周毓  王启明  李建斌 《天文研究与技术》2011,8(1)

为适应FAST项目索网结构索单元应力测量的需求,设计并制作了一种以频率法测索力理论为基础的无线式索力传感器节点。首先阐明了FAST工程中使用无线式索力传感器的必要性和优势;其次给出了频率法测索力的理论依据;重点介绍了基于MMA7260加速度计芯片的无线式索力传感器节点的硬件及软件设计;最后对传感器进行了对照实验。实验结果表明:该无线式传感器能准确拾取钢索振动信号,索内应力与一阶振动频率的一致性较好,为FAST日后施工过程的索力测量积累了经验。  相似文献   

基于LinuxPPS的高精度校时系统实现     

于佳  胡柯良  邓元勇  商朝晖 《云南天文台台刊》2012,(1):39-45

为了实现南极天文观测设备的精确校时,采用搭建高精度网络时间协议NTP（Network Time Protoc01）服务器的方法实现。基本思路是从NMEA0183数据中提取时间信息,通过PPS信号保证高精度。具体实现方法：主要采用GPS接收芯片G591构造硬件电路,软件部分需要LinuxPPS（Linux Pulse Per Second）和NTP服务器软件的正确安装和配置。对照实验表明基于LinuxPPS的NTP服务器是精确、稳定而可靠的。  相似文献   

1米太阳望远镜液压监控系统     

赵雪娟  柳光乾  张涛 《云南天文台台刊》2012,(2):162-167

1m太阳望远镜的方位驱动控制系统采用液压轴承,液压系统正常工作时望远镜才能实现平稳旋转。可通过油压、油温监测液压系统的工作状态。针对原有液压系统不能提供其工作状态实时监测和自动化程度较低的缺陷,设计了液压监控系统并将其集成到望远镜控制系统中,可实现油压油温数据采集、油压异常报警、油泵自动启停等功能,保证液压轴承的安全运转。介绍了该监控系统的结构和工作原理,阐述了油压、油温数据采集系统的软硬件实现并给出了相应的实验数据和运行结果。理论分析和实验结果表明系统工作正常,数据采集速度快、分辨率高,精度可满足要求,能长期稳定运行。  相似文献   

高分辨率遥感影像在核电站厂址普选中的应用初探     

高春林  曾敬文 《北京测绘》2013,(3):93-95,36

国家核电正处于新的发展时期,核电站厂址普选正在全国范围内展开。本文针对目前核电站厂址普选过程中所采用方式方法,探讨了一种利用高分辨率遥感影像进行核电站厂址普选的方法,并简要分析了这种方法的可行性及优点。  相似文献   

Observed dynamic soil–structure interaction in scale testing of offshore wind turbine foundations     

《Soil Dynamics and Earthquake Engineering》2013

Monopile foundations have been commonly used to support offshore wind turbine generators (WTGs), but this type of foundation encounters economic and technical limitations for larger WTGs in water depths exceeding 30 m. Offshore wind farm projects are increasingly turning to alternative multipod foundations (for example tetrapod, jacket and tripods) supported on shallow foundations to reduce the environmental effects of piling noise. However the characteristics of these foundations under dynamic loading or long term cyclic wind turbine loading are not fully understood. This paper summarises the results from a series of small scaled tests (1:100, 1:150 and 1:200) of a complete National Renewable Energy Laboratory (NREL) wind turbine model on three types of foundations: monopiles, symmetric tetrapod and asymmetric tripod. The test bed used consists of either kaolin clay or sand and up to 1.4 million loading cycles were applied. The results showed that the multipod foundations (symmetric or asymmetric) exhibit two closely spaced natural frequencies corresponding to the rocking modes of vibration in two principle axes. Furthermore, the corresponding two spectral peaks change with repeated cycles of loading and they converge for symmetric tetrapods but not for asymmetric tripods. From the fatigue design point of view, the two spectral peaks for multipod foundations broaden the range of frequencies that can be excited by the broadband nature of the environmental loading (wind and wave) thereby impacting the extent of motions. Thus the system lifespan (number of cycles to failure) may effectively increase for symmetric foundations as the two peaks will tend to converge. However, for asymmetric foundations the system life may continue to be affected adversely as the two peaks will not converge. In this sense, designers should prefer symmetric foundations to asymmetric foundations.  相似文献   

全球地震柱的地震层析成像证据     

陈立军  胡奉湘  陈晓逢 《华南地震》2013,(4):1-10

依据地震地热说原理,搜集国内外地震层析成像研究的成果．揭示了地震柱的物理属性。得出全球24个地震柱中已有资料的20个地震柱的深部地幔圆锥体均具有P波高速异常体特征,相反,只有火山和浅源地震活动而无中、深源地震活动的地区,比如冰岛和夏威夷,其地幔深部则为P波低速异常体。为解释这个重要的物理现象和构造现象,引入空化理论解释并提出了3个假设。地震柱概念是地震地热说赖以生存的物质基础和构造基础,是与当今流行的地质学派板块构造、地质力学和地幔柱理论的最大区别。深入解读地震柱的物理属性及其构造学意义．或许能为构造地质学和地球动力学带来革命性的大讨论。  相似文献   

The importance of being reliable – Local ecological knowledge and management of forage plants in a dryland pastoral system (Morocco)     

《Journal of Arid Environments》2013

In dryland rangelands with their high environmental variability, local ecological knowledge of forage plants is essential for management decisions. Ecological apparency hypothesis (EAH) predicts plants' availability and visibility to be important criteria for local valuation. However, EAH has mainly been tested in low-variability systems. We ask whether EAH is valid for forage plants in drylands; which other local criteria exist; and how criteria are connected to management decisions.In a Moroccan pastoral system, we applied a novel ethnobotanical method by calculating the Cognitive Salience Index (CSI) for plants' valuation (CSI_antro) and availability (CSI_eco). To evaluate explicit criteria, we correlated palatability and nutritive value to CSI_anthro. ANCOVAs related CSI_anthro to EAH criteria (CSI_eco and lifetime) and to plant occurrence on pasture types. We found EAH criteria to better predict CSI_antro than explicit criteria. Apparent plants from semi-arid pastures were more valued than those from arid pastures (HSD; p < 0.05). We introduce the criterion of reliability into EAH to explain this, and demonstrate how pastoralists adjust management decisions to resource reliability. Linking resource valuation to management decisions can thus improve our understanding of resilience mechanisms. Our study also confirms the validity of EAH for forage species and dryland environments.  相似文献   

INFLUENCE OF SUBARCTIC VEGETATION COVER ON SNOWMELT     

J. E. FitzGibbon  T. Dunne 《自然地理学》2013,34(1):61-70

An examination of the three major components of the energy balance has shown that subarctic vegetation cover markedly alters the relative importance of these components for the snowmelt. It has been found that the contribution of net radiation decreases as forest cover decreases while sensible and latent heat contributions to the snowmelt increase with decreasing forest cover. The decrease in the importance of net radiation with decreasing forest cover is due to the effect of the forest cover on albedo and the effects of the forest cover on the long-wave radiation component of the radiation balance. This situation seems to be typical for open canopy forests. The increase in importance of sensible and latent heat in the open is due to the increase in wind speed from the forest to open sites.  相似文献   

高纯碳酸锶清洁生产国内外研究进展   总被引：4，自引：4，他引：0       下载免费PDF全文

刘建明  段东平  钟莉  韩宏亮  周娥 《盐湖研究》2013,(2):66-72

高纯碳酸锶是一种高附加价值的重要锶化合物,由于它具有独特的物理化学性能,因而被广泛应用于电子、化工、材料等领域。但高纯碳酸锶的生产仍存在环境污染严重、产品质量难以稳定控制、生产成本高等问题。综述了国内外高纯碳酸锶清洁生产工艺研究与应用进展,详细介绍了天青石碳还原法、天青石复分解法、粗碳酸锶酸溶碱析法、粗碳酸锶焙烧分解法、硝酸锶法、氯化锶法等高纯碳酸锶主要生产工艺的研究与应用进展,评述了各生产工艺产生的污染物的净化处理方法与技术改进,剖析了各工艺的优点和存在的问题。结合我国目前高纯碳酸锶的生产现状及与国外生产技术存在的差距,并对我国高纯碳酸锶生产技术的发展方向进行了展望。  相似文献