Influence of the Choice of Core-Envelope Transition Point on the Binary Merger of Two Main-sequence Components     

Xue-Fei Chen  Zhan-Wen HanNational Astronomical Observatories  Yunnan Observatory  Chinese Academy of Sciences. Kunming  Graduate School of the Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2005,5(1):65-76

We have studied the influence of different choices of core-envelope transition point on the final merger of contact binaries with two main-sequence components. A binary of 1.00 + 0.90M⊙ with an initial orbital period of 0.35d is examined. The mass fraction of the primary mixed with the matter of the secondary, qmix, determined by the chosen core-envelope transition point, ranges from 0.04 to 1.00 in our analysis. If as qmix< 0.8, none of the  相似文献   

Stellar collisions in galactic centres: black hole growth and colour gradients     

Qingjuan Yu † 《Monthly notices of the Royal Astronomical Society》2003,339(1):189-211

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The radial distribution of blue straggler stars and the nature of their progenitors     

M. Mapelli  S. Sigurdsson  F. R. Ferraro  M. Colpi  A. Possenti  B. Lanzoni 《Monthly notices of the Royal Astronomical Society》2006,373(1):361-368

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分光光度法测定海洋河弧菌510脂多糖     

张运涛  顾谦群  方玉春  吕元萌  管华诗 《中国海洋大学学报(自然科学版)》2003,33(3):355-360

本文研究了直接测定海洋河弧菌 (vibrio fluvailis) 5 10脂多糖的分光光度法。利用 1,9-二甲基亚甲蓝 (DMB) ,在适当条件下同脂多糖发生染色反应 ,在 5 5 0 nm波长下 ,反应体系的吸光值同脂多糖含量呈线性相关。相关系数为 0 .9993,最低检出限为 10 μg/m L,相对标准偏差为 1.6 2 ,平均回收率为 (10 5± 2 .18) %。  相似文献   

Sustainable shellfish aquaculture in Saldanha Bay,South Africa     

A Santa Marta  JG Ferreira  GC Pitcher  J Lencart e Silva 《African Journal of Marine Science》2020,42(2):151-166

The carrying capacity for bivalve shellfish culture in Saldanha Bay, South Africa, was analysed through the application of the well-tested EcoWin ecological model, in order to simulate key ecosystem variables. The model was set up using: (i) oceanographic and water-quality data collected from Saldanha Bay, and (ii) culture-practice information provided by local shellfish farmers. EcoWin successfully reproduced key ecological processes, simulating an annual mean phytoplankton biomass of 7.5 µg Chl a l^–1 and an annual harvested shellfish biomass of about 3 000 tonnes (t) y^–1, in good agreement with reported yield. The maximum annual carrying capacity of Small Bay was estimated as 20 000 t live weight (LW) of oysters Crassostrea gigas, or alternatively 5 100 t LW of mussels Mytilus galloprovincialis, and for Big Bay as 100 000 t LW of oysters. Two production scenarios were investigated for Small Bay: a production of 4 000 t LW y^–1 of mussels, and the most profitable scenario for oysters of 19 700 t LW y^–1. The main conclusions of this work are: (i) in 2015–2016, both Small Bay and Big Bay were below their maximum production capacity; (ii) the current production of shellfish potentially removes 85% of the human nitrogen inputs; (iii) a maximum-production scenario in both Big Bay and Small Bay would result in phytoplankton depletion in the farmed area; (iv) increasing the production intensity in Big Bay would probably impact the existing cultures in Small Bay; and (v) the production in Small Bay could be increased, resulting in higher income for farmers.  相似文献   

催化分光光度法测定痕量钛   总被引：2，自引：0，他引：2  

周之荣  吴伟 《岩矿测试》1996,15(3):235-237

催化分光光度法测定痕量钛周之荣１吴伟华东地质学院应化系江西临川３４４０００催化褪色光度法测定钛的报道较少［１］，本文研究了痕量Ｔｉ（Ⅳ）催化过氧化氢氧化酸性铬蓝Ｋ褪色反应的影响因素，建立了测定痕量Ｔｉ（Ⅳ）的催化光度法，并用于测定植物及人发中钛。方法...  相似文献   

河南内乡-淅川-带的虎睛石矿床及开发利用     

刘国范  杨振军李铭 马庚杰 《华南地质与矿产》2005,(1):68-71

研究区虎睛石矿床在地质特征、矿物组合、化学成分及琢雕效果等方面与国外虎睛石矿床是完全不同的，属于一种特殊的罕见类型。在分析虎睛石地质特征、开发利用现状的基础上，认为该区的虎睛石资源丰富，琢雕效果好，在国内外市场上具有一定的竞争力和良好的开发利用前景。  相似文献   

The first fossil Perilestidae (Odonata: Zygoptera) from mid-Cretaceous Burmese amber     

《Cretaceous Research》2016

Palaeoperilestes electronicus gen. et sp. nov. is the first perilestid damselfly described from mid-Cretaceous Burmese amber. This new damselfly can be attributed to the family Perilestidae by the midfork being distal of the subnodus and the base of IR2 quite near to the base of RP2, both features found in the extant genera Perilestes and Perissolestes. Palaeoperilestes electronicus gen. et sp. nov. has a strongly zigzagged IR1, however, differing from Perilestes and Perissolestes which have a straight IR1. The discovery not only adds to the diversity of damselflies in Burmese amber, but also puts the origin of Perilestidae back to at least the mid-Cretaceous.  相似文献   

The oldest armoured harvestman (Arachnida: Opiliones: Laniatores), from Upper Cretaceous Myanmar amber     

《Cretaceous Research》2016

The oldest laniatorean harvestman, Petrobunoides sharmai gen. et sp. nov. (Opiliones: Laniatores) is described, from the Upper Cretaceous (lowermost Cenomanian) amber of Myanmar. This is the first fossil Laniatores recovered from Southeast Asia, which is placed in the extant family Epedanidae. It is also the first fossil known within the superfamily Epedanoidea; a relatively derived clade of Laniatores restricted to Southeast Asia today. At ca. 99 Ma, this new amber inclusion is substantially older than the previous oldest record of a member of Laniatores from Baltic amber (ca. 44–49 Ma); however, given the Palaeozoic age of Laniatores implied by molecular data, the new record from Burmese amber is probably still too young for constraining or calibrating the date of cladogenesis for total group Laniatores. Nevertheless, it provides a much better constraint for Epedanoidea, adding the first useful laniatorean fossil to provide an internal calibration point for a clade of Grassatores.  相似文献   

The first araripeneurine antlion in Burmese amber (Neuroptera: Myrmeleontidae)     

《Cretaceous Research》2016

Burmaneura minuta gen. et sp. nov., the first araripeneurine antlion in amber, is characterized, described and compared with the modern and Mesozoic Myrmeleontidae. The precise position of the fossil within this group is debatable. Interestingly, despite a rather rich fossil record, all Mesozoic Myrmeleontidae belong to subfamilies that are not recorded in the Cenozoic, although this might merely reflect the artificiality of the classification as the extinct groups may be paraphyletic with respect to their younger counterparts (e.g., Araripeneurinae may very well be nothing more than a stem group of no classificatory value).  相似文献