DISTRIBUTION OF THE MAIN CROP GERMPLASM RESOURCES IN CHINA   总被引：1，自引：0，他引：1  

曹永生  张贤珍  白建军  龚高法 《中国地理科学(英文版)》1997,7(4):310-316

Cropgermplasmresourcesaretheindispensablematerialbaseforcropbreedingandagriculturalproduction.Theresearchondistributionofcropgermplasmr~urcesisofgreatimportanceinstudyingonorigin,evolutionandclassificationofcrops,expeditingandcollectinggermplasm,ascertainingofcentersofdiversity,protectinggermplasmr~urcesandmakingagriculturalproductiondivision.Since1949,researchesofexploration,collection,preservation,cha-racterizationandevaluationofcropgermplasmresourceshavebeendoneinChina.Atpresent,thenational…  相似文献   

Coronal oscillations as revealed by solar hard X-ray bursts     

Yong-xuan Xu  Yun-geng Cao 《Chinese Astronomy and Astrophysics》1986,10(4):306-312

During the 21st solar activity cycle the HXRBS aboard SMM satellite and the HXM on HINOTORI spacecraft detected several thousand hard X-ray solar flares. Studies of the temporal properties of these events had revealed hundreds of examples of fast spikes with durations of less than 1 sec. We analysed part of these observations and found that they have four common characteristics. Among these characteristics, quasi-periodic oscillations led us to believe the possibility of oscillations existing in the corona. We have studied the characteristics of the oscillations and derived their periods. The conditions of trapping the oscillations are also discussed.  相似文献   

日冕物质抛射和太阳表面磁活动的关系   总被引：2，自引：0，他引：2  

周桂萍  曹卓良  汪景琇 《天文学进展》2003,21(1):41-54

综述了近年来日冕物质抛射与耀斑、日珥、冕流和日冕暗化相关关系的研究进展，指出了这些相关关系上的一些不确定因素。同时，介绍了我们所做的部分工作，探讨了不同尺度磁活动之间的物理联系，并提出今后需要进一步解决的问题。  相似文献   

SOME PRELIMINARY RESULTS FROM STUDY OF CRUSTAL DEFORMATION IN VIETNAM     

Cao Dinh Trieu  Le Van Dung  Nguyen Huu Tuyen  Pham Nam Hung 《大地测量与地球动力学》2003,23(Z1)

1　IntroductionOneofthemaintasksinstudyinggeodynamicprocessisevaluatingtherateofearthcrustmove ments.Normally ,themethodsforstudyingearthcrustmovementareestablishedonthebasisoftheobjectofstudyandtherequirementsfortheresultstobeobtainedasfollows.1 )Tostudythemovingprocessofcrustplatesinalargeareaandwithinacertaintectonicperiod ,geologicmethodsareusuallyused .2 )Geodeticmeasurementsarecarriedoutinanareacoveringfromsomekm2 totensofkm2 andal lowtodeterminethedisplacementoftheearthcrustwithinaperio…  相似文献   

Two Different Dust Storms in Northeast China:the Sources and Influences in East Asia     

Ke Hu  Yuying Liu  Zhen Cao 《东北亚地学研究》2003,(1)

Dust storms in Northeast China become more se-rious in recent years due to the global warming and local land use and cover change (LUCC) around the sand lands in western and northwestern Jilin Province. Field investigations and urban testing re-vealed that the amount of dusts brought by dust storm reaches a higher level in the past two years. According to an experiment on the “mud-snow”in April, 2000 and an observation in March, 2002, the dusts coming from the western Jilin and fall…  相似文献   

日冕和行星际空间中的太阳射电Ⅱ型爆发     

曹文达  杨开平  陈国强 《天文研究与技术》1994,(1)

本文以近２０年来Ⅱ型爆发的地面观测和空间观测的巨大成就，概述了Ⅱ型爆发的主要特征，源的结构、大小和运动；着重介绍了Ⅱ型爆发激发机制和辐射机制的最新理论；最后讨论了目前观测和理论研究中存在的问题。  相似文献   

豫西煤田重力滑动构造形成条件分析     

曹代勇  王昌贤 《河南国土资源》1994,(1)

重力滑动构造广泛发育，是豫西煤田构造格局显著特征之一。本文分析了导致煤田重力滑动构造形成的动力学条件、构造变形条件、岩性条件和流体介质条件，讨论了此类特殊构造现象与其所处的特殊构造环境之间的关系。  相似文献   

Relation between blue/ultraviolet continuum shape and the ratio of radio-to-optical emission for B3-VLA quasars     

Minfeng Gu  Xinwu Cao  D. R. Jiang  Y. Xu 《Monthly notices of the Royal Astronomical Society》2001,321(2):369-371

The low-frequency radio luminosity is believed to be an indicator of jet power, while the optical/ultraviolet (UV) emission is probably from accretion discs in the nuclei of steep-spectrum radio quasars. We present a correlation between the ratio of radio-to-optical luminosities and the continuum spectral index in blue/UV bands, which might indicate that the continuum shape in blue/UV bands is related to the ratio of jet to accretion power. The results may imply that the spectra and structure of accretion discs are probably affected by the interactions between jets and discs.  相似文献   

Morphological features of spotless flares and a possible theoretical model     

Cao Tian-jun 《Chinese Astronomy and Astrophysics》1983,7(4):305-308

We summarize the morphological features of spotless flares as observed by three Chinese observatories (Yunnan Purple Mountain and Beijing) during the peak years of the 21st solar cycle. On the basis of the Kippenhahn-Schluter model of solar prominences, we qualitatively interpret these observed features and propose a possible theoretical model of generating spotless flares.  相似文献   

The theory of relativity and super-luminal-speeds     

Cao Shenglin 《Astrophysics and Space Science》1990,174(2):165-171

According to our Paper I (Cao Shenglin, 1988), it could be supposed that the physical space-time is a Finsler space-time, characterized by the metric ds ⁴=g _ijkf dx ⁱ dx ^j dx ^k dx ^f . If so, a new space-time transformation could be found by invariant ds ⁴ and the theory of relativity is discussed on this transformation.The project supported by National Natural Science Foundation of China.  相似文献