基于USB2.0的海床基自动监测平台数据接口单元的研究     

黄战华  刘正  高瑞  张毅  蔡怀宇 《海洋技术学报》2007,26(3):1-4

采用EZ-USB FX2技术,设计开发了基于USB2.0的海床基自动监测平台数据接口方式。采用三态双向门电路控制存储器模块总线复用实现数据访问;采用直接内存读写方法完成数据传输;采用参数存储器完成参数设置。实验证明在数据传输、参数设置以及低功耗控制方面取得良好效果,提高了系统工作性能。  相似文献   

2006～2007年北部湾海-气热通量变化特征     

盛立芳  郑元鑫  陈静静  王丹 《中国海洋大学学报(自然科学版)》2009,39(4)

用2006年夏～2007年秋在北部湾获得的船测气象资料,由块体公式计算了海-气通量.结果表明:北部湾春、夏季节获得热通量,而秋、冬季节失去热通量.春季通过湍流交换造成的热通量对海面热平衡的贡献最小,其次是夏季、冬季和秋季.在年平均尺度上感热通量和潜热通量分别占净辐射通量的7.4%和77.4%,15.2%的净辐射热量通过海洋过程消耗掉.感热通量随海-气温差的加大而增大,而与风速之间呈现复杂的非线性关系.海-气温差增加1 ℃,感热通量增加6.7～12.7 W/m2;较大的感热通量(>30 W/m2)容易出现在5～10 m/s风速条件下.潜热通量与风速和相对湿度呈明显的相关关系:风速增加1 m/s,潜热通量增加约18 W/m2,而相对湿度下降1%会导致6 W/m2潜热通量的增加.  相似文献   

基于WSE3.0实现Web服务安全的应用     

付永军  唐慧佳 《成都信息工程学院学报》2007,22(4):453-457

针对目前Web服务安全开发工具包WSE3.0技术的应用研究,分析其策略体系结构及实现Web服务安全的过程,并讲述使用WSE3.0实现的Web服务安全功能.  相似文献   

Perihelion motion of small irregular dust particles due to radiation forces     

J. Kla?ka  F. Kundracík 《Planetary and Space Science》2006,54(4):379-393

Perihelion motion, i.e. a secular change of longitude of perihelion, of interplanetary dust particles is investigated under the action of solar gravity and solar electromagnetic radiation. As for spherical particle [Kla?ka, J., 2004. Electromagnetic radiation and motion of a particle. Cel. Mech. Dynam. Astron. 89, 1-61]: (i) perihelion motion is of the order ( is heliocentric velocity of the meteoroid and c is the speed of light in vacuum), if a component of electromagnetic radiation acceleration is considered as a part of central acceleration; (ii) perihelion motion is of the first order in if the total electromagnetic radiation force is considered as a disturbing force. The new facts presented in this paper concern irregular dust particles. Detailed numerical calculations were performed for the grains ejected at aphelion of comet Encke. Perihelion motion for irregular interplanetary dust particles exists already in the first order in for both cases of central accelerations. Moreover, perihelion motion of irregular particles exhibits both positive and negative directions during the particle orbital motion. Irregularity of the grains causes not only perihelion motion, but also dispersion of the dust in various directions, also normal to the orbital plane of the parent body.  相似文献   

NUMERICAL SIMULATION OF SSTA IMPACTS OVER THE GLOBAL OCEAN ON THE ANOMALOUS CIRCULATION OVER EURASIA IN JANUARY 2008     

李琰  朱伟军 《热带气象学报(英文版)》2010,16(3):238-246

In this paper,we discussed the features of atmospheric circulations over Eurasia as a response to sea surface temperature anomalies (SSTAs) over the tropical Indian Ocean,the equatorial Pacific,Kuroshio and the North Atlantic.Our results are shown as follows: (1) CAM3.0,driven by the combined SSTAs over the four oceanic regions,can simulate well the features of anomalous atmospheric circulations over Eurasia in January 2008,indicating that the effects of the SSTAs over these four regions were one of the key causes of the anomalous systems over Eurasia.(2) The SSTAs over each key region contributed to the intensification of blocking over the Urals Mountains and a main East Asian trough.However,the influence of the SSTAs over individual oceanic regions differed from one another in other aspects.The SSTAs over the North Atlantic had an impact on the 500-hPa anomalous height (Z500A) over the middle-high latitudes and had a somewhat smaller effect over the low latitudes.For the warm SSTAs over Kuroshio,the subtropical high was much stronger,spread farther north than usual,and had an anomalous easterly that dominated the northwest Pacific Ocean.The warm SSTAs over the tropical Indian Ocean could have caused a negative Z500A from West Asia to Middle Asia,a remarkably anomalous southwesterly from the Indian Ocean to the south of China and an anomalous anticyclone circulation over the South China Sea-Philippine Sea region.Because of the La Nia event,the winter monsoon was stronger than normal,with an anomalously cooler northerly over the southeastern coastal areas of China.(3) The combined effects of the SSTAs over the four key regions were likely more important to the atmospheric circulation anomalies of January 2008 over Eurasia than the effects of individual or partly combined SSTAs.This unique SSTA distribution possibly led to the circulation anomalies over Eurasia in January 2008,especially the atmospheric circulation anomalies over the subtropics,which were more similar to those of the winter El Ni?o events than to the circulation anomalies following La Nia.  相似文献   

Deep optical observations of the interaction of the SS 433 microquasar jet with the W50 radio continuum shell     

P. Boumis  J. Meaburn  J. Alikakos  M. P. Redman  S. Akras  F. Mavromatakis  J. A. López  A. Caulet  C. D. Goudis 《Monthly notices of the Royal Astronomical Society》2007,381(1):308-318

  相似文献   

气候变化综合评估模型   总被引：1，自引：0，他引：1  

张雪芹  葛全胜 《地理科学进展》1999,18(1):60-67

本文概述了气候变化综合评估模型（IAM）的定义、组成、特点及应用。IAM可视为一种促进人类更好地理解气候变化问题的工具,它为研究者和决策者提供了一种十分有益的关注环境问题的框架或方法论。  相似文献   

A 2.8 Ma record of environmental evolution and tectonic events inferred from the Cuoe core in the middle of Tibetan Plateau   总被引：1，自引：0，他引：1  

Ji?ShenEmail author  Houyuan?Lü  Sumin?Wang  Shiyue?Chen  Xiangdong?Yang  Yanhong?Wu  Zhaoyu?Zhu 《中国科学D辑(英文版)》2004,47(11):1025-1034

Based on a multi-proxy investigation into the deep core of the Cuoe Lake in the middle of Tibetan Plateau, a 2.8 Ma paleoclimatic and paleoenvironmental evolution is reconstructed. The result of magnetic stratum indicates that the lake basin was formed at about 2.8 MaBP, while the multi-proxy analyses of lithology, grain size, magnetic susceptibility and geochemical elements reveal that there have been three major environmental evolution stages and at least two intensive uplifts of the Tibetan Plateau in the lake basin area, i.e. during 2.8-2.5 MaBP, the lake basin came into being as a result of the disaggregation of the planation surface and rapid rising of the Tibetan Plateau. During 2.5-0.8 MaBP, with gradual uplift of the Tibetan Plateau, the environment of this area was more effectively controlled by the climatic cycle of the alternative glacial-interglacial stages. After 0.8 MaBP, the middle part of the Plateau accelerated its uplift and entered cryoshere.  相似文献   

A new VLBI observation of an OH maser in a post-asymptotic giant branch star using the European VLBI Network     

Yu Zhi-yao 《Monthly notices of the Royal Astronomical Society》1998,299(2):389-391

OH 17.7 − 2.0 is a post-asymptotic giant branch star that is of great interest. The 1612-MHz OH emission from OH 17.7 − 2.0 is characterized by a double-peaked spectrum. Such a line profile has been assumed to represent maser emission from an expanding circumstellar shell. A new VLBI observation of the OH maser in OH 17.7 − 2.0 has been made using the European VLBI Network, and a relative position map of the eight OH maser spots has been obtained. Using the relative position map, it is found that the eight OH maser spots are distributed on an expanding circumstellar shell. The parameters of the expanding circumstellar shell have been obtained.  相似文献   

黄土高原西部白草塬剖面L₁和S₁记录的古地磁场特征   总被引：1，自引：0，他引：1       下载免费PDF全文

邓成龙 《第四纪研究》2008,28(5):854-865

文章详细介绍了黄土高原西部白草塬剖面L₁和S₁的高精度岩石磁学和古地磁学结果,讨论了白草塬剖面记录古地磁场的特征,从古地磁学角度探讨白草塬剖面黄土沉积的连续性。白草塬剖面黄土沉积物中,磁铁矿和磁赤铁矿是主要的亚铁磁性矿物,粗粒的碎屑磁铁矿是其天然剩磁和特征剩磁的主要载体。白草塬剖面L₁和S₁没有记录任何地磁漂移。其中,L₁没有记录MonoLake或Laschamp地磁漂移的原因可归结于黄土沉积物堆积过程的不连续性和/或粗颗粒载磁矿物的重磁化,但前者是主要原因,而堆积过程的不连续性是导致S₁没有记录Blake地磁漂移的主要原因。因此,白草塬剖面的L₁和S₁分别存在约2000年和4000～6000年的沉积不连续。  相似文献