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951.
本文利用COS-B和HEAO-B卫星资料对Geminga脉冲星进行了守时性分析和谱分析,结果进一步证实了Geminga脉冲星是一颗具有强γ辐射,弱X辐射的γ射线脉冲星.  相似文献   
952.
南海区多鱼种声学评估工作程序   总被引:3,自引:0,他引:3  
总结了利用SimradEK50 0声学系统进行了南海区多鱼种资源评估经验 ,介绍了多鱼种声学评估的工作流程 ,包括调查方案制定、声学数据采集、映像分析、积分值分配、资源量的计算方法等关键过程 ,同时及在工作中应该注意的细节。  相似文献   
953.
1 IntroductionGeographicalinformationsystem (GIS)isanefficientwayandimportanttechniquetomanage,displayandanalyzeAntarcticspatialdata.GIScanbeusedtomakeandre newmapproductsquickly ,evaluateenvironment,supportlogisticmanagementandfieldoperation,providechancetoextractnewknowledge,andtopromoteinformationex changeamongnationsunderthedemandoftheMadridProtocol(AADC 2 0 0 1 ;MAGIC1 998;1 999) .WorkingGroupofGeodesyandGeographicInformation (WG GGI)ofScientificCommitteeonAntarcticResearch (…  相似文献   
954.
In this paper we investigate the range of variation of the orbital inclination I between two bodies in the problem of three bodies. We give the conditions to determine whether the two bodies move in the same or opposite senses and give the maximum and minimum values of I when the three bodies are in collinear positions. We prove that the range of variation of I must attain maximum and minimum values when the bodies are collinear.  相似文献   
955.
The early stage differentiation of thallus cells ofPorphyra haitanensis T. J. Chang et B. F. Zheng was studied. Protoplasts or single cells were isolated from the blades using enzyme mixture comprising 2% sea snail gut enzyme and 1% cellulase. The isolated protoplasts or single cells were incubated in the MES medium. The cell differentiations were examined under the microscope at intervals after incubation. Four types of cell differentiation, namely, normal, abnormal, carposporangial and spermatorangial, and rhizoidal types, were observed. Since normal cell differentiations occur mostly in small thalli 50 mm in length and middle portions of big thalli 200 mm in length, it is essential to select tissues from these two kinds of thalli essential for commercial production.  相似文献   
956.
957.
The strongly peraluminous granites (SPGs) of Eastern Nanling Range (ENR) are a characteristic of all bearing highly aluminous minerals, such as muscovite±AI-rich biotite±tourmaline±garnet, and lack of cordierite. In respect of petrography, geochemistry, Nd isotope, and single grain zircon U-Pb dating, the representative granite bodies of them are studied. The research shows that these granites were emplaced in two stages, namely 228-225 Ma BP and J2-3 159-156 Ma BP, belonging to Indosinian and early Yanshanian periods, respectively, and they have low εNd(t) values (-10.6--11.1), high A/CNK, Rb/Sr ratios and tDM values (1887-1817 Ma), and REE's tetrad effect (TE1,3=1.13-1.34). In comparison with related geology, petrology and chronology of granites in adjacent regions, it is suggested that Indosinian SPGs of ENR formed in the circumstance of post-collisional extension 20 Ma after the major collision of Indosinian Movement (258-243 Ma BP) in Indo-China Peninsula, and early Yanshanian SPGs formed in the  相似文献   
958.
Studies on the deep-seated xenoliths from global volcanoes reveal that the present petrological crust-mantle boundary between the lower crust and the upper mantle actually is a transitional layer from mainly mafic granulites to ultramafic spinel lher-zolites[1,2], i.e. a transitional zone distinctive from the seismological Moho[3]. Oceanic lithosphere crust- mantle transitional zone can be established from the study on the exposed ophiolites. However, as for the continental lithosphere, since …  相似文献   
959.
960.
In order to forecast storm surge inundation, a two-dimensional model is established. In the model, an alternating computation sequence method is used to solve the governing equations, and the dry and wet method is introduced to treat the moving boundary. This model is easy to use. It has a friendly input interface and Arcview GIS is used as the output interface. The model is applied to the Shantou area to simulate the storm surge elevations and inundations caused by Typhoons 6903 ane 0104 using the same relevant parameters. The calculated results agree well with the observations.  相似文献   
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