巨分子云聚合形成N体模拟中粒子数的效应

通过N体数值模拟以不同粒子数对星系中巨分子云的形成的影响进行了研究。结果表明：在聚合形成机制下，当对不同数目的分子云取相同的平均密度时，基本分子云的有效半径与其相应质量的立方根成正比，巨分子云的碎裂率与模拟基本分子云的数目无关。     

南海西南部新生代盆地类型及演化历史

南海西南部地区发育了多种类型的新生代沉积盆地，各种类型的盆地具有各自的结构特征和演化历史，走滑－周缘前陆盆地－曾母盆地发育了渐新－中中新统层系，晚中新统层系和上新－第四系层系第三套地层，曾母盆地经历了三个发育阶段，拉张剪切盆地－万安盆地发育下第三系－下渐新统层系，上渐新统一中中新统层系和上中新统一第四系层系三套地层，万安盆地经历了四个发育阶段。     

Environmental evolution of Zoigê Basin since 900 kaB.P. and comparison study with Loess Plateau

The Zoige Basin is located in the eastern margin of the Qinghai-Xizang Plateau, in which two cores, RH and RM, have been drilled, with the depths of 120 m and 310 m respectively. The former with the bottom age of 826 kaB. P. has been divided into 21 stages according to the multi-proxy analysis, which could be basically compared with the oxygen isotope record of deep-sea core. The palaeoclimatic and palaeoenvironmental process of the Zoigê Basin over the past 900 kaB. P. is reconstructed, and the comparison of core RH with the Luochuan Loess record is made.     

Isotopic Composition of Dissolved Carbonates Meromictic Soda Lake Doroninskoe(Eastern Transbaikalia,Russia)

正1 Introduction Meromictic soda Lake Doroninskoe localized in the intermountain area,filled with continental sediments of the Mesozoic,in the upper basin of the river Amur.Coordinates of its location are N51°14'42"E112°14'40",     

Distribution and Forming Model of Fluvial Terrace in the Huangshui Catchment and its Tectonic Indication

<正>The Huang Shui River,a main tributary of the Yellow River,crosses a series of tectonically subsided and uplifted areas that show different patterns of terrace formation.The distribution of fluvial terrace of the Huang Shui River is studied through topographic and sedimentologic terrace mapping.Three terraces in the Haiyan Basin,four terraces in the Huangyuan Basin,19 terraces in the Xi'ning Basin(the four high terraces may belong to another river),nine terraces in the Ping'an Basin, five terraces in the Ledu Basin and 12 terraces in the Minhe Basin are recognized.Sedimentology research shows that the geomorphologic and sedimentological pattern of the Huang Shui River,which is located at the margin of Tibet,are different from that of the rivers at other regions.The formation process of the terrace is more complicated at the Huang Shui catchment:both accumulation terrace and erosion terrace were formed in each basin and accumulation terraces were developed in some basins when erosion terraces were formed in other basins,indicating fluvial aggradation may occur in some basins simultaneously with river incision in other basins.A conceptual model of the formation process of these two kinds of fluvial terraces at Huang Shui catchment is brought forward in this paper.First,the equilibrium state of the river is broken because of climatic change and/or tectonic movement,and the river incises in all basins in the whole catchment until reaching a new equilibrium state.Then,the downstream basin subsides quickly and the equilibrium state is broken again,and the river incises at upstream basins while the river accumulates at the subsidence basin quickly until approaching a new equilibrium state again.Finally,the river incises in the whole catchment because of climatic change and/or tectonic movement and the accumulation terrace is formed at the subsidence basin while the erosion terrace is formed at other basins.The existence of the accumulation terrace implied the tectonic subsidence in the sub-basins in Huang Shui catchment.These tectonic subsidence movements gradually developed from the downstream Minhe Basin to the upstream Huangyuan Basin.Dating the terrace sequence has potential to uncover the relationship between the subsidence in the catchment and the regional tectonic at the northeastern Tibetan Plateau.     

中朝边境天池破火山口湖底地形多波束测深探测

为调查天池破火山口湖的基本参数和湖底地形特征,研究破火山口的内部构造、破火山口的组合样式和垮塌堆积分布,本文采用多波束测深方法,对天池湖底地形进行了探测。探测结果显示:天池最大水深值为373.2m,天池水域边界实测周长为13.44km,天池湖水面面积9.4km~2,天池总蓄水量约为19.88×10~8m~3。天池周边分布4个温泉,温度为7~47℃。根据湖底地形推断,现今的天池破火山口形成于千年大喷发。其后,在天池西侧形成一个喷火口,东侧形成一个熔岩丘。天池湖底存在5个较大的破火山口内壁垮塌堆积区,但在湖底未见熔岩流。天池边缘出露的温泉点对应环状断裂,同时反映深部存在岩浆体。     

大别山构造带东段杨山组煤的变质演化

采用地史分析与数值模拟相结合的研究方法,对下石炭统杨山组煤的变质演化历程进行了定性和定量研究。结果表明:杨山组煤的变质作用经历了海西旋回中期和燕山旋回中-晚期两个演化阶段,煤级在第一阶段异常低热古地热场中深成变质作用下达到焦煤,第二阶段却在异常高热古地热场导致的热变质作用下剧增至超无烟煤。在包括研究区在内的大别山构造带北麓,海西旋回中期可能具有冷盆的特征,而燕山旋回中-晚期却表现出热盆的性质。     

Using bright ellipticals as dark energy cosmic clocks

The age of the Universe has been increasingly constrained by different techniques, such as the observations of type Ia supernovae (SNIa) at high redshift or dating the stellar populations of globular clusters. In this paper, we present a complementary approach using the colours of the brightest elliptical galaxies in clusters over a wide redshift range  ( z ≲ 1)  . We put new and independent bounds on the dark energy equation of state parametrized by a constant pressure-to-density ratio   w _Q  and by a parameter (ξ) which determines the scaling between the matter and dark energy densities. We find that accurate estimates of the metallicities of the stellar populations in moderate and high-redshift cluster galaxies can pose stringent constraints on the parameters that describe dark energy. Our results are in good agreement with the analysis of dark energy models using SNIa data as a constraint. Accurate estimates of the metallicities of stellar populations in cluster galaxies at   z ≲ 2  will make this approach a powerful complement to studies of cosmological parameters using high-redshift SNIa.     

Polyclonal antibodies to light-harvesting CHL-protein of PSII (LHC II) in marine green algaeBryopsis corticulans

Polyc·lonal antibodies raised against LHC II isolated from SDS-solubilizedBryopsis corticulans thylakiod membranes by SDS-PAGE, were characterised by double immunodiffusion, Rocket immunoelectrophoresis and antigen-antibody crossed immunoelectro-phoresis assays showed the antibodies had strong cross-reaction with allB. corticulans LHC II components (even with those which were incubated in boiling water) and showed immunological cross-reactivity with LHC II polypeptides of spinach and the marine green algaCodium fragile. The results suggested that LHC II of different species had similar antigenic determinants and also conservation of amino acid sequences of the polypeptides during evolution, and that the antibodies could cross react with apoproteins of D₂ proteins (which contain P₆₈₀) fromB. corticulans, spinach andC. fragile, but not with apoproteins of P₇₀₀ Chl-proteins. Our results indicated some similarities in primary structure between LHC II of different species, and between LHC II and D₂ proteins of marine green algae and spinach. Our finding that D₂ and P₇₀₀ Chl-proteins are not immunologically related suggested that P₇₀₀ Chl-proteins and D₂ proteins pass through independent evolutionary pathways. Contribution No 1717 from the Institute of Oceanology, Academia Sinica, This subject was supported by the National Science Foundation of China.     

Interacting effects of multiple factors on the morphological evolution of the meandering reaches downstream the Three Gorges Dam

Elucidating the influence of dams on fluvial processes can inform river protection and basin management. However, relatively few studies have focused on how multiple factors interact to affect the morphological evolution of meandering reaches. Using hydrological and topographical data, we analyzed the factors that influence and regulate the meandering reaches downstream the Three Gorges Dam (TGD). Our conclusions are as follows. (1) The meandering reaches can be classified into two types based on their evolution during the pre-dam period: G1 reaches, characterized by convex point bar erosion and concave channel deposition (CECD), and G2 reaches, characterized by convex point bar deposition and concave channel erosion (CDCE). Both reach types exhibited CECD features during the post-dam period. (2) Flow processes and sediment transport are the factors that caused serious erosion of the low beaches located in the convex point bars. However, changes in the river regime, river boundaries and jacking of Dongting Lake do not act as primary controls on the morphological evolution of the meandering reaches. (3) Flood discharges ranging from 20,000 to 25,000 m³/s result in greater erosion of convex point bars. The point bars become scoured if the durations of these flows, which are close to bankfull discharge, exceed 20 days. In addition, the reduction in bedload causes the decreasing of point bar siltation in the water-falling period. (4) During the post-dam period, flood abatement, the increased duration of discharges ranging from 20,000 to 25,000 m³/s, and a significant reduction in sediment transport are the main factors that caused meandering reaches to show CECD features. Our results are relevant to other meandering reaches, where they can inform estimates of riverbed change, river management strategies and river protection.