井冈山自然保护区甜槠群落物种多样性分析

以甜槠群落6个样地调查资料为基础,对该群落的区系组成和不同样地、不同层次的物种多样性进行了分析,结果表明:(1)甜槠群落中有维管植物59科85属116种(含变种);属的地理成分以热带成分占优势,温带成分占有一定的比例。(2)乔木层、灌木层和草本层的各项物种多样性指标在群落各样地间均有一定的差异;在群落垂直结构中,灌木层的多样性指数最大,乔木层次之,草本层最小。     

C－isotope composition and significance of the Sinian on the Tarim plate

102 samples of limestones,mudrocks shales and tillites from the Sinian in Kuluketage have been analyzed ,Four formations in the Sinian belong to glacial deposits in which the differences in δ^13C are distinct (-14.7‰- 4.2‰),Distinctly negative δ^13C excursions for three times support the viwe of three glacial deposits in this area suggested by previous authors,except for the durations of them ,δ^13C values are generally positive in the Beiyixi Formation of lower part of the Lower Sinian ,representing probably the rock records of a continental rift related to break-up of the Rodinian supercontinent,There are three times of distinct excursions of δ^13C curve in all strata,The first one is from positive values at the bottom to about -5‰ at the top of the Beiyixi Formation ,The second one,from 0‰-3‰ in the Arletonggou Formation of upper part of the Lower Sinian to -3.4‰---14.4‰ in the Teruiaiken Formation.The third one,from positive values in the Zhamoketi Formation of lower part of the Upper Sinian to negative values in glacial varves at the top of the Hankeerqiaoke Formation.     

Inorganic chemical composition and source signature of PM2.5 in Beijing during ACE-Asia period

Aerosol samples for PM2.5 were collected in Beijing for 38 consecutive days from March to April 2001 using an IMPROVE Sampler. Concentrations of 20 elements in PM2.5 were determined using a PIXE method. Results show that the average mineral dust concentration of PM2.5 was 14.6 Ilg/m3 during the observation period. On the sand-dust event days of March 21 and April 10, dust PM2.5 mass concentrations were 62.4 and 54.1 μg/m^3, respectively.These demonstrate that fine particle pollution by dust event in Beijing was very severe. The enrichment factors of S and Cu reached minimums on the dusty days and were high on the non-dusty days. It is considered that enrichment factors of elements in PM2.5, which are associated with human activities, can probably provide an effective method to distinguish local sources from external sources of dust. Factor analysis on the chemical composition in PM2.5 shows that sources of crustal matters, anthropogenic emission, and oil combustion contributed to PM2.5 levels in air in the springtime of 2001 in Beijing.     

Isotopic evolution of the terminal Neoproterozoic and early Cambrian carbon cycle on the northern Yangtze Platform, South China

Profound geotectonic, climatic and biological changes occur during the terminal Neoproterozoic and its transition into the early Cambrian. These are reflected in temporal variations of the chemical and isotopic composition of seawater. We are studying a sequence of sedimentary rocks at the Shatan section, northern Yangtze Platform, Sichuan Province of China. This succession comprises, in ascending stratigraphic order, predominantly calcareous sediments of the Sinian upper Dengying Formation and black shales of the lower Cambrian Guojiaba Formation (time equivalent of Niutitang Fm.). Paleoenvironmental setting represents shallow-water shelf deposits. The objective of our study is to provide temporal records for the isotopic compositions of organic and carbonate carbon throughout this time interval. Organic carbon isotope values display a range between -35.8‰ and -30.1‰ with clear stratigraphic variations. Carbonate carbon isotope data vary between -3.5‰ and +0.5‰. These secular variations are interpreted to reflect perturbations of the global carbon cycle, specifically changes in the fractional burial of organic carbon. However, local conditions have further affected the isotopic signals.     

Structural and Chemical Diversity of TI-Based Cuprate Superconductors

The first TI一based euprate supereonduetor,TI一Ba-Cu一(),was diseovered by 2.2.Sheng and A.M.Hermann仁1〕. TI beeomes supereondueting at 2.38 K.NumerousTI eompounds and alloys are supereondueting.TIMo6Ses has the highest transition temperature of1 2.2 K among all non一euprate Tl eontaining alloyand eompound supereonduetors.Before thediseovery of the euprate supereonduetors,some TIeontaining oxide supereonduetors were found,among whieh TI。.3W()3 has the highest transitiontemPerature,2.14 K. Sinee the diseovery of TI euPratesuPereonduetors,two distinet families have beenidentified.Soon after the diseovery of TI一Ba一Cu-(),supereonduetivity was eonfirmed in TI一Ba一Ca-Cu一()samples.The ehemieal eompositions anderystal struetures of those eompounds were workedout as T12BaZCu()6,T12BaZCaCuZ()。,andT12BaZCaZCu3OI。[2〕.This 15 the first family of TIeuPrate supereonduetors,whieh features two TIatoms in eaeh ehemieal formula.     

兰州北山生物结皮中陆生藻种类组成与群落结构

通过对沙井驿、刘家堡、九州台、白塔山、小牛圈沟等样点采集的生物结皮样的培养和鉴定 ,研究了兰州市北山生物结皮中陆生藻种类组成及其群落结构 .结果发现 ,该地陆生藻共计 5 3种 ,其中蓝藻 34种 ,绿藻 7种 ,硅藻10种 ,裸藻 2种 .蓝藻中以丝状种类占优势 (6 5 % ) ,绿藻中仍以球状种类居多 (5 7% ) ,但也有不少丝状个体(43% ) .黄土结皮以非洲席藻为第一优势种 ,石崖表具鞘微鞘藻占绝对优势 ,人工草丛中小球藻最丰富 ;种类数在砾质黄土中最多 (2 3) ,黄粘土中最少 (16 ) .     

作业成本法在物流成本管理中的应用

论述了企业物流成本管理中存在的问题,系统地阐述了运用作业成本法进行企业物流成本管理的可行性和具体操作要求,最后提出了作业成本法在物流成本管理中的应用对策.     

沥青路面罩面的设计方法

针对国内外罩面或改建设计方法的不足 ,借助于同济大学对新建和罩面改建后的沥青路面使用性能的研究成果 ,将寿命周期费用分析引入罩面设计 ,提出了沥青路面罩面设计方法———基于使用性能和技术经济分析的最佳罩面时机和最佳罩面厚度选择方法 ,并通过实例说明了该方法的应用     

加入WTO对我国工程造价计价模式的影响

中国建筑产品价格市场化经历了三个发展阶段,其最终目标是要建立以市场形成价格的价格机制.在上述进程中,出现了传统的定额计价方法与市场定价方法并存现象.但是由于定额计价方法影响了市场机制的作用,我国工程造价必然转向国际通行的清单计价方式,同时也就要求与工程量清单计价模式相适应的配套措施改革.     

不同碳源对红边朱蕉组培苗生长的影响

从碳源角度进行了降低红边朱蕉组培苗生产成本的试验；比较分析了蔗糖、葡萄糖、果糖、食用白糖和红糖等5种碳源对红边朱蕉试管苗增殖速度、根诱导效率、内含物积累的影响，分别以蔗糖、葡萄糖、果糖、白糖、红糖为碳源培养4周，培养物均能很好地生长、生根，同时有利于可溶性糖和蛋白质的积累。结果表明，在组培快繁中。为降低成本，可以食用白糖、红糖等为碳源，替代分析纯蔗糖。