Gamma-ray burst energy spectra: theoretical models,old and new

The M, S and C stars may be placed in an evolutionary sequence on the basis of direct observation of the spectroscopic transitions on the AGB of rich intermediate-age clusters in the Magellanic Clouds, but some S and C stars cannot be accounted for in this way. The S stars in Centauri owe their peculiarity to a primordial enrichment in s-process elements. The J-type (¹³C-rich) carbon stars originate in a different way to the ordinary cool N-type carbon stars. Some of them have silicate-rich circumstellar dust, contrary to expectation. Some of the carbon-rich RV Tauri stars also have silicate-rich dust and in both cases it may be organised in a disc. Observational evidence for gas and dust ejection by ordinary N-type carbon stars has been found and may be inferred for some RV Tauri stars.     

全息区域论探

本文应用宇宙全息论精神重新定义区域的概念,所得结论:“区域是人类与地表自然界相互联系,相互作用的全息系统,是与周围部分有相对边界的相对独立部分.区域与区域之间,区域与整体之间存在着全息对应关系,它们之间的区别只是全息度和全息级的不同”.本文还吸取进化论的观点,剖析区域的基本单元─-自然村,探讨区域的进化问题.初步总结出了区域的基本全息元(自然村)向高一级区域全息元(镇)进化的模式:“进化-选择-跃升”.至于镇以上各级区域全息元的特征及其进化问题,需另文论述.     

多甲藻素在一种海生黄藻中的存在

采用聚酰胺薄层层析分离、分光光度法，对一种海生超微型黄藻品系PP983的色素组成进行了研究测定。结果表明，该黄藻中只含有叶绿素a 而不含叶绿素c,检出8种类胡萝卡素，除作为黄藻特征色素的Heteroxanthin和Vacheriaxanthin两种外，还发现该藻含有一个吸收峰在471nm，呈现多甲藻素（peridinin）特征的色素。用高效液相色谱（HPLC），并以微小多甲藻（peridinium pusillum）作对照，对其光合色素作进一步的分析，确证该黄藻中不含有叶绿素c而含多甲藻素。结果显示此种黄藻与甲藻有更近的亲缘关系。初步讨论了黄藻中多甲藻素的存在及其在藻类系统演化中的意义。     

南四湖的形成及水环境演变

采用重力活塞取样器在南四湖的独山湖和微山湖分别采取了两个湖底沉积剖面的样品。通过对湖底沉积物高分辨率的粒度、矿物、磁化率、有机碳、色素等环境指标和沉积年代学的综合研究 ,结合研究区的历史文献资料 ,探讨了南四湖形成近 2 5ka以来的水环境演变过程。研究表明 ,南四湖的形成和发展可分为 4个阶段 :初时 ,湖区为古泗水及其沿岸平原 ;西汉时期古泗水中下游段形成分散的湖沼地 ;唐—明代受黄河夺泗入淮和开挖京杭运河等人类活动的影响 ,湖沼扩张、合并 ;清同治 1 1年黄河大决于东明后 ,先后出现的南阳、昭阳、独山、微山四湖合并为统一的南四湖。     

关中地区重力场及其时空动态演化特征

系统分析了关中地区1992～2004年流动重力测量资料，研究了重力场的时空动态演化特征。10多年来的重力场动态变化图象表明：重力场变化与活动断裂构造密切相关，重力场有规律的变化与区域应力-应变场微动态活动有关。区域重力场总的趋势变化为：关中南部秦岭山区重力负值变化，测区中部渭河断陷盆地至韩城一带重力正值变化，测区北部铜川-黄龙一带的渭北黄土塬重力负值变化。西安城区重力变化主要是过量开采地下水、含水系统压密所致。     

老挝中-东部大型铁铜金矿矿集区矿床地质--对云南"三江"地区找金的启示

矿集区分布在NW向川塘-长山华力西断皱带南西缘，系多陆块拼接缝合构造环境。印支-燕山期-喜马拉雅期花岗岩类岩浆活动及其相关的成矿作用，通过高效率浓集机制，形成一串锡、铁、铜、金等矽卡岩型、斑岩型和热液型矿床，组成矿床系列，包括多个超大型、大型矿床。这些成因上密切相关的矿床，成矿时间显然相近，却处在不同岩浆活动阶段和不同地质环境中，矿化特征有明显差异，矿种和矿化类型在时空分布上具有规律：印支-燕山期的花岗岩侵入阶段形成矽卡岩型富磁铁矿矿床；在花岗岩浆分异演化浅成相侵入阶段，形成矽卡岩型及岩浆晚期、自交代产生的斑岩型；而最后形成岩浆期后热液型铁-金、铜、金矿床。文章侧重讨论铁、铜、金矿床系列的成矿构造环境、岩浆作用、物质来源及高效率浓集机制，对云南“三江”地区找金有重要启示。     

The effects of a variation of the radial viscosity profile on mantle evolution

The present paper describes a set of numerical experiments on the mantle's thermal evolution with an infinite Prandtl number fluid in a compressible spherical shell heated mainly from within. We used the anelastic liquid approximation with Earth-like material parameters. The usual variable-viscosity approach in mantle-convection models is the assumption of a temperature dependence only. The resulting thermal boundary layers are included in our model also, but an additional viscosity profile of the interior mantle was derived: The Birch–Murnaghan equation was employed to derive the Grüneisen parameter and other physical quantities as a function of depth from observational values provided by PREM. We computed the melting temperature and a new mantle viscosity profile, called eta3, using the Grüneisen parameter, Lindemann's law and some solid-state physics considerations. The new features of eta3 are a high-viscosity transition layer with rather high viscosity gradients at its boundaries, a second low-viscosity layer beginning under the 660-km discontinuity, and a strong viscosity increase in the central parts of the lower mantle. The rheology is Newtonian but it is supplemented by a viscoplastic yield stress, σ_y. A viscosity-level parameter, r_n, and σ_y have been varied. For a medium-sized Rayleigh-number–yield-stress area, eta3 generates a stable, plate-tectonic behavior near the surface and simultaneously thin sheet-like downwellings in the depth. Outside this area, three other types of solution were found. Not only the planforms but also the evolution of the Rayleigh number, the reciprocal Urey number, the Nusselt number, the surface heat flow, etc., have been studied. We repeated this investigation with two very different basic viscosity profiles, etaKL5a and etaKM, of other authors. A comparison reveals that eta3 facilitates the generation of surface plates and thin sheet-like downwellings in the depth considerably more than etaKL5a or even etaKM. The presence of two internal low-viscosity layers is obviously conducive for plateness and thin sheet-like downwellings. For an infinite yield stress, the thin cold sheet-like downwellings are reticularly connected. However, the distribution of the downwellings is more Earth-like if a realistic yield stress is added.     

中国地图制图技术的演进与前瞻

中国地图科学工作者在继承和发扬祖国地图科学光辉传统的同时,吸取地球科学,空间技术和信息工程等学科的现代成就,使当代地图科学技术取得长足的进展,几十年来,航空摄影与系列制图,航天遥感与动态制图,计算机制图与电子地图,地理信息系统与制印一体化等先进科学技术已取得瞩目成绩,专题地图集的编制与信息时代相呼应,出现一些新观念,新技术,随着地球信息科学新学科的兴起,地图科学将出现新机遇,新挑战。     

乌兰布和沙漠北部沉积物特征及环境意义

根据乌兰布和沙漠北部地区典型剖面记录,对各层沉积物进行了结构分析;在对沉积物性质、特点进行分析判断的基础上,初步揭示了各层沉积物的环境意义,并以此对乌兰布沙漠的形成、发展与环境变迁间的关系作了初步探讨。认为乌兰布和沙漠的形成演化主要受自然环境变化的影响,人为因素应是叠加其上的辅助因素。     

噻吩类化合物——判识海相原油类型和评价高演化碳酸盐岩烃源岩成熟度的理想生物标志物

现被广泛应用的有机岩石学成熟度评价方法和有机地球化学成熟度参数在评价海相高演化碳酸盐岩烃源岩时具有很大的局限性。噻吩类化合物具有高度的热稳定性和抗微生物分解性,在碳酸盐岩中含量丰富,易于鉴定和定量计算,成熟度参数值跨度大,用其判识塔里木盆地原油的烃源岩类型、区分塔里木盆地高成熟原油的成熟度取得了良好的效果。通过进一步研究其成熟度参数与 R_0的关系,可望建立海相高演化碳酸盐岩成熟度评价标准和方法。