自研透射式能见度测量系统性能分析     

汪玮  张世国  章超  方海涛  王敏 《气象科技》2020,48(2):163-170

从系统测量原理、组成结构、计算过程及测量效果等方面介绍了一种自行研制的透射式能见度测量系统。该系统使用白色LED光源,实现发散角为1mrad的平行光路;利用积分球进行分光监控以补偿光能量变化;使用非球面镜实现全光斑接收。系统与积分浊度计在2～10km量程内能见度测试误差小于10%。从透射式能见度测量原理与计算过程,分析了影响系统测量性能的因素。结果显示定标准确性、测量线性度与系统稳定性是影响系统测量性能的主要因素,同时给出了该系统的定标准确性、测量线性度与系统稳定性的评估方法及评估数据,验证了该系统的测量性能。  相似文献   

CC天气雷达数据流传输业务台站级监控报警系统的设计与实现     

甄廷忠  唐学军  张琪  方夏馨 《气象科技》2020,48(3):368-373

利用UDP组播通信、进程监控、文件监控、网络监控等技术,研发了CC天气雷达数据流传输业务台站级监控报警系统,较早、较好地实现了雷达扫描状态、数据流上行传输、标准格式基数据本地存储、基数据补传、软件运行和网络运行状态的实时监控和短信报警。实践表明,软件运行较稳定,能对数据流传输业务进行有效监控,短信报警准确及时,报警阈值从6min缩短到40s,提升了故障的发现和处理效率,提高了天气雷达业务可用性和数据传输质量,减轻了雷达台站业务人员的值守压力。  相似文献   

沿海渔业天气警报服务系统     

王雪森  林朝昌 《成都信息工程学院学报》1993,(1)

本文简要地介绍了建立沿海渔业天气警报服务系统的必要性,系统的设计特点,现场试验情况以及今后建台布网的设想。特别是把短波单边带通信,地面波传播方式和双音报警技术引入天气警报服务系统,开辟了短波单边带气象通应用的新领域。  相似文献   

无线信道中传输高速数据的试验报告     

沈镇芳  龚一光  李景彬 《成都信息工程学院学报》1993,(1)

本文主要介绍了利用无线信道传输9600bps数据信号的的几种试验方案,并对其进行了评价,供各界参考。  相似文献   

面向多种网络带宽环境的远程教学视频传输技术研究   总被引：1，自引：0，他引：1  

龚自康 《武汉大学学报(信息科学版)》2006,31(4):368-371

面向网络教育教学视频传输的需求，对视频传输所涉及的视频编码、网络带宽自适应等一些关键技术进行了研究。  相似文献   

广西大范围暴雨期间孟加拉湾强对流演变及东移特征     

李向红  黄嘉宏 《气象科技》2006,34(2):151-156

分析1980~2002年主汛期(5~7月)广西锋面型大范围暴雨期间孟加拉湾对流云团演变及与之相应高低空环流变化,结果表明:孟加拉湾强对流在广西暴雨发生前3天发展最为旺盛,受孟加拉湾低槽引导,对流云团爬上中南半岛进入广西,当其与高原东移的云团相结合时再次发展,造成广西大范围暴雨。分析200 hPa高度场和流场结果表明:当广西暴雨发生时,孟加拉湾、中南半岛及广西受200 hPa南亚高压控制。分析850 hPa水汽通量矢量场结果表明:广西锋面型暴雨发生时,从孟加拉湾到广西上空有一西南气流的水汽输送带,广西暴雨水汽主要来源于孟加拉湾。  相似文献   

关于(超)高压输变电系统地震安全性评价工作的认识     

杨成林  王辉  黄河 《东北地震研究》2007,23(2):76-80

通过对(超)高压输变电系统在社会经济中的地位及其地震破坏情况的简要分析,确认了(超)高压输变电系统工程属于"重大建设工程"的范畴,必须开展相应的地震安全性评价工作。输变电系统具有远距离,长跨越的特点,其抗震设防标准应分段作评定。  相似文献   

Seismic reflection and transmission coefficients of a self-similar interface   总被引：1，自引：0，他引：1  

Kees Wapenaar 《Geophysical Journal International》1998,135(2):585-594

The derivation of seismic reflection and transmission coefficients is generally based on the assumption that the medium parameters behave as step functions of depth, at least in a finite region around the interface. However, outliers observed in well logs generally behave quite differently from step functions. In this paper we represent an interface by a self-similar singularity, embedded between two homogeneous half-spaces, and we derive its frequency-dependent normal-incidence reflection and transmission coefficients. For ω  → 0 the expressions for the coefficients reduce to those for a discrete boundary between two homogeneous half-spaces; for ω → ∞ they become frequency-independent. These asymptotic expressions have a relatively simple form and depend on the singularity exponent α .
  The exact as well as the asymptotic expressions are used to evaluate the time-domain reflection and transmission responses of a self-similar interface. Finally, we use a numerical method to model the response of a smoothed version of a self-similar interface (note that the velocity of a smoothed singularity remains finite). It turns out that smoothing has hardly any effect on the response, provided that the smoothing does not affect the scales corresponding to the seismic frequency range.  相似文献   

Histological and Histochemical Analyses of the Cuttlebone Sac of the Golden Cuttlefish Sepia esculenta     

ZHENG Xiaodong XIAO Shu WANG Zhaoping WANG Rucai 《中国海洋大学学报(英文版)》2007,6(4):393-397

The secretion function of mantle is closely related to shell formation in some bivalves and gastropods. Up to now, few researches have been reported for cuttlebone formation in the class Cephalopoda. In this study, the structure and secretion function of cuttlebone sac of the golden cuttlefish Sepia esculenta was analyzed using the histological and histochemical methods. The results showed that high and columnar cells located in sac epithelium, and flat cells existed near the base membrane. A lot of fibroblasts were found in the lateral mantle collective tissue. Some mucus, mucopolysaccharide and alkaline phosphatase (ALP) were found in the sac. The ultrastructural characteristics of Quasi-connective-tissue-calcium cells (QCTCC) were observed using a transmission electron microscope (TEM). The relationship between cuttlebone sac secretion function and shell formation was discussed.  相似文献   

Elastic waves at a corrugated interface between two dissimilar fibre‐reinforced elastic half‐spaces     

Sanasam Sarat Singh  S. K. Tomar 《国际地质力学数值与分析法杂志》2007,31(9):1085-1116

The reflection and transmission phenomena of elastic waves incident at a corrugated interface between two dissimilar fibre‐reinforced elastic half‐spaces have been analysed. Using Rayleigh method of approximation, the expressions of the reflection and transmission coefficients are obtained in closed form for the plane interface as well as for the first order approximation of the periodic interface ζ = d cos px. All these reflection and transmission coefficients of regular and irregular waves are found to be the functions of angle of incidence and elastic parameters of the media. Moreover, the coefficients of irregularly reflected and transmitted waves are found to be proportional to the amplitude of the corrugated interface and are functions of the frequency of the incident wave. Numerical computations have been performed for a specific model to compute these coefficients and results obtained are shown graphically. The results of Singh and Singh (Sadhana 2004; 29 :249–257) and Ben‐Menahem and Singh (Seismic Waves and Sources. Springer: New York) have been derived from our analysis as particular cases. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献