| 1 | Iterative Solution of Regularization to Ill-conditioned Problems in Geodesy and Geophysics显示文摘In geodesy and geophysics,many large-scale over-determined linear equations need to be solved which are often ill-conditioned.When the conjugate gradient method is used,their ill-conditioning effects to the solutions must be overcome,which is studied in this paper.Through the regularization ideas,the conjugate gradient method is improved,and the regularization iterative solution based on controlling condition number is put forward.Firstly by constructing the interference source vector,a new equation is derived with ill-condition diminished greatly,which has the same solution to the original normal equation.Then the new equation is solved by conjugate gradient method.Finally the effectiveness of the new method is verified by some numerical experiments of airborne gravity downward to the earth surface.In the numerical experiments the new method is compared with LS,CG and Tikhonov methods,and its accuracy is the highest. | Yongwei GU Qingming GUI Xuan ZHANG Songhui HAN | 2019 | Journal of Geodesy and Geoinformation Science2019，2，1： | 4 |
| 4 | Characterization of Amphidinium(Amphidiniales,Dinophyceae)species from the China Sea based on morphological,molecular,and pigment data显示文摘Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems.Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and pharmaceutical potentials.The diversity of Amphidinium in shallow waters along the Chinese coast was investigated by isolating single cells from sand,coral,and macroalgal samples collected from 2012 to 2020.Their morphologies were subjected to examination using light microscopy(LM)and scanning electron microscopy(SEM).A total of 74 Amphidinium strains were morphologically identified,belonging to 11 species:A.carterae,A.gibbosum,A.operculatum,A.massartii,A.cf.massartii,A.fijiensis,A.pseudomassartii,A.steinii,A.thermaeum,A.theodori,A.tomasii,as well as an undefined species.The last seven species have not been previously reported in Chinese waters.Amphidinium carterae subcladesⅠ,Ⅱ,andⅣwere found in the South China Sea,while subcladeⅢwas only found in the Yellow Sea.Threadlike body scales were observed on the surface of subcladesⅢ and Ⅳ,supporting the idea that A.carterae might contain several different species.Large subunit ribosomal RNA(LSU rRNA)sequencesbased phylogeny revealed two groups(GroupsⅠandⅡ)within Amphidinium,which is consistent with the relative position of sulcus(in touch with cingulum or not).In addition,large differences in morphology and molecular phylogeny between A.operculatum(the type species of Amphidinium)and other species,suggest that a subdivision of Amphidinium might be needed.The pigment profiles of all available strains were analyzed by high performance liquid chromatography(HPLC).Eleven pigments,including peridinin,diadinoxanthin,diatoxanthin,pheophorbide(and pheophorbide a),antheraxanthin,β-carotene,and four different chlorophylls were detected.The high pheophorbide/pheophorbide a ratio in Amphidinium implies that it may be a good candidate as a natural source of photosensitizers,a well-known anticancer drug. | Zhaohe LUO Hua ZHANG Qun LI Lei WANG Hala F MOHAMED Songhui LÜ Haifeng GU | 2022 | Journal of Oceanology and Limnology2022，40，3： | 1 |
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