UBV RI CCD photometric study of the open clusters Basel 4 and NGC 7067     

R. K. S. Yadav  Ram Sagar 《Monthly notices of the Royal Astronomical Society》2004,349(4):1481-1492

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运输系统的区域效应研究   总被引：1，自引：0，他引：1  

高小真 《地理学报》1991,46(1):93-102

运输系统改进—运距缩短—产业布局调整这一空间过程对不同的区域可能具有完全不同的意义。本文通过对一个两区域—两部门经济模型的研究得出结论:当较落后的资源产区与经济中心之间的距离由于运输系统的改进而缩短时,资源产区的经济结构向单一化转变,初级产品的生产和输出在经济建设中逐渐占主导地位,加工工业逐渐萎缩,地方经济发展受到阻碍,而且这种变化是在距离的某一特定值处突然出现的,带有跃变的性质。这一研究结果表明,对区域运输系统的任何改进措施都应该慎而行之,以免造成与本来目标相悖的区域效应。  相似文献   

Spectroscopic binaries near the North Galactic Pole paper 18: HD 118670     

R. F. Griffin 《Journal of Astrophysics and Astronomy》1990,11(4):533-540

Photoelectric radial-velocity measurements show that HD 118670 is a double-lined spectroscopic binary in an orbit which is not quite circular and whose period is about 48 days. Spectral types of K0 V and K7 V would satisfy the photometry and the mass ratio; the mass function would then suggest the possibility of eclipses. However, actual spectral classification indicates a luminosity somewhat above the main sequence  相似文献   

维生素C对胡子鲶生长、免疫与抗病作用的影响   总被引：2，自引：0，他引：2  

李桂峰  钱沛锋 《广东海洋大学学报》2004,24(4):17-22

在胡子鲶基础料中分别添加 0、5 0 0、10 0 0、15 0 0、2 0 0 0mg/kg的维生素C(VC) ,分别在饲喂不同实验料后的第 12、2 4、36和 5 2天 ,测定各组的生长指标、血清的溶血活力和杀菌活力 ;并在饲喂后的第 4 0天 ,用鲁氏不动杆菌进行攻毒实验 ,观察胡子鲶死亡情况。结果表明 ,添加VC对胡子鲶体重、特定生长率和体长增长率有提高作用 ,但无规律性 ;在添加后的第 12、2 4、36天对血清溶血活力有明显的提高作用 ;对血清杀菌活力没有增强作用。攻毒结果表明 ,VC能明显提高胡子鲶对鲁氏不动杆菌的抵抗力  相似文献   

Minor planet short periodic perturbations: The indirect part of the disturbing function     

Zoran Knežević 《Celestial Mechanics and Dynamical Astronomy》1993,55(4):387-404

Leverrier's development of the indirect part of the disturbing function has been extended to include terms up to degree 4 in eccentricity and inclination; the resulting series has been expressed with respect to a fixed plane, and in a computer readable form (a list of integers). Tests have been performed for the relative significance of the terms of degrees 2, 3 and 4, and estimates have been obtained for the accuracy of the short periodic perturbations of a minor planet, and of the corresponding mean orbital elements. It was found that: (i) even in extreme cases, the indirect part of the disturbing function gives rise to very small short periodic perturbations; (ii) bodies of very high eccentricity/inclination and those close to mean motion resonances are most significantly affected; (iii) indirect perturbations for minor planets can be computed up to the degree 2 terms only, without any significant loss of accuracy; and (iv) higher degree indirect perturbations appear to be important only for their contribution to the long periodic effects of higher order (with respect to the perturbing mass).  相似文献   

CHARACTERIZATION OF LACTATE DEHYDROGENASE ISOZYME PATTERN AND MORPHOLOGY OF THREE MARINE FISH CELL LINES     

郭华荣  张士璀  李红岩  童裳亮  相建海 《中国海洋湖沼学报》2002,20(3):226-231

Three continuous marine fish cell lines of FG (i. e., Hounder Gill) from flounder (Paralichthys olivaceus) gill, SPH (i. e. , Sea Perch Heart) from sea perch (Lateolabrax japonicus) heart and RSBF (i.e., Red Sea Bream Fin) from red sea bream (Pagrosomus major) fin, were characterized by lactate dehydrogenase (LDH) isozyme and morphological analysis. The LDH isozyme patterns of these three cell lines and their corresponding tissues of origin were investigated and compared. The results showed: (1) No difference was found in the LDH isozyme patterns of FG and flounder gill tissue. However, the LDH isozyme patterns of SPH and RSBF were significantly different from their corresponding tissues of origin; (2) LDH isozyme patterns of FG, SPH and RSBF were markedly different from each other and could serve as genetic markers for species identification and detection of cross contamination. Morphological change analysis of these three cell lines in comparison to their original tissues indicated that FG cells still appeared epithelioid without morphological transformation. However, morphological changes were found in SPH and RSBF compared to their original tissues. Therefore, the cellular morphology was still plastic in the relatively stable culture conditions, and it was possible that change of LDH patterns wasrelated to morphological changes of fish cells in vitro.  相似文献   

Galaxy merging, the fundamental plane of elliptical galaxies and the  M_BH−σ₀  relation     

C. Nipoti  P. Londrillo  L. Ciotti 《Monthly notices of the Royal Astronomical Society》2003,342(2):501-512

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Black hole winds     

A. R. King  K. A. Pounds 《Monthly notices of the Royal Astronomical Society》2003,345(2):657-659

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A comparison of the acceleration mechanisms in young stellar objects and active galactic nuclei jets     

D. J. Price  J. E. Pringle  A. R. King 《Monthly notices of the Royal Astronomical Society》2003,339(4):1223-1236

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Dynamical response to supernova-induced gas removal in two-component spherical galaxies     

Masahiro Nagashima &#;  Yuzuru Yoshii 《Monthly notices of the Royal Astronomical Society》2003,340(2):509-518

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