星系形成与演化半解析理论研究的新进展     

赵东海 《天文学进展》2000,18(1):83-87

发展了的星系形成和演化的半解析理论,可以很好地再现不同红移时宇宙恒星形成率密度（ＳＦＲ）和中性气体共动密度的最新观测结果。对该理论各个不确定性因素对结果的影响作了说尽的讨论,并指出在中等红移星系间的相互作用可能是主宰恒星形成的决定性因素,根据宇宙学模型对观测和半解析理论的影响,对宇宙学参数作出限制。  相似文献   

Diatom diet selectivity by early post-larval abalone Haliotis diversicolor supertexta under hatchery conditions     

张玉宇  高亚辉  梁君荣  陈长平  赵东海  李雪松  李扬  吴文忠 《中国海洋湖沼学报》2010,28(6):1187-1194

Benthic diatoms constitute the primary diet of abalone during their early stages of development. To evaluate the dietary preferences of early post-larval abalone, Haliotis diversicolor supertexta, we analyzed the gut contents of post-larvae that settled on diatom films. We compared the abundance and species diversity of diatom assemblages in the gut to those of the epiphytic diatom assemblages on the attachment films, and identified 40 benthic diatom species in the gut contents of post-larvae 12 to 24 d after settlement. The most abundant taxa in the gut contents were Navicula spp., Amphora copulate, and Amphora coffeaeformis. Navicula spp. accounted for 64.0% of the cell density. In the attachment films, we identified 110 diatom species belonging to 38 genera. Pennate diatoms were the dominant members including the species Amphiprora alata, Cocconeis placentula var. euglypta, Cylindrotheca closterium, Navicula sp. 2, and A. coffeaeformis. Nano-diatoms (<20 μm in length) accounted for a considerable proportion of the total species number and cell density of the diatom assemblages in the gut contents and on the films. This suggests that nano-diatoms are important to the efficient production of abalone seed. The difference of the composition and abundance of diatoms between in the guts and on the biofilms suggests that early post-larval grazing was selective. An early post-larval abalone preferred nano-diatoms and the genera Navicula and Amphora during the month after settlement.  相似文献   

初始谱指数为-1的非线性重谱(Bispectrum)     

侯永辉  景益鹏  赵东海 《天文学报》2005,46(4):364-379

重谱即傅立叶空间的三点相关函数，是研究由引力不稳定性产生的大尺度结构的最低非高斯阶统计性质．在傅立叶空间中，发现二维和三维空间的统计性质是等价的，相对三维快速傅立叶，二维快速傅立叶变换可以节省很多计算机资源．结合二维和三维的快速傅立叶变换，利用高精度的初始谱指数为-1的N体数值模拟，测量了从弱线性区域到强非线性区域的重谱．在测量过程中，考虑并严格校正了作用于功率谱和重谱上的数值效应，如离散效应（particle discreteness）、软化因子（force softening）、模拟盒子的大小、混淆效应（alias effect）．发现约化重谱即使在强非线性区域仍然依赖于三角形的形状和尺度，并随着波数的增加而增加，这和前人的假设完全不同．在测量结果的基础上，拟合了重谱的一个适用于初始谱指数为-1的宇宙学模型的经验公式．  相似文献   

硅藻在鲍育苗中的重要作用研究进展   总被引：2，自引：0，他引：2  

赵东海  高亚辉  吴文忠  陈旭新 《海洋科学》2005,29(9):90-93

近年来，鲍鱼（Haliotis）养殖规模不断扩大，养殖量也不断上升。2000年中国商品鲍产量已达到2000吨以上。但目前养鲍业中普遍存在着养殖稳定性低、病害严重等急需解决的问题。  相似文献