三种金银矿物的初步研究及其意义     

孙启松 《湖南地质》1994,13(4):201-204

湘西某金矿区发现的三种金银矿物，其化学成分分别为金银汞互化物和银汞互化物。本文就其镜下特征、产出形态、共生矿物、成因等作一简要介绍，期望引起关注，促进深入研究。  相似文献   

冰云光学特性与等效球Mie理论的误差分析     

张国栋 《成都信息工程学院学报》1997,(4)

用改进的射线光学理论和等效球Ｍｉｅ理论，计算了若干冰晶和冰晶尺度分布在太阳光谱区中一系列波长上的光学特性和散射特性，详细分析了Ｍｉｅ散射计算的误差，并假定冰云光学特性有１０％误差的情况下，用Ｄｅｌｔａ－Ｅｄｄｉｎｇｔｏｎ近似对所引起的冰云辐射特性的误差进行了数值试验。结果表明，沿用已久的等效球Ｍｉｅ理论因计算冰云光学特性在波长小于２．６μｍ波段误差过大，将引起冰云辐射特性有显著误差，最后提出了计算冰云光学特性的新方案。  相似文献   

Terraced fills of Pleistocene and Holocene age in the Rheidol Valley,Wales     

Mark G. Macklin  John Lewin 《第四纪科学杂志》1986,1(1):21-34

The legacy of repeated Pleistocene glaciations has endowed many Welsh river valleys with locally thick successions of glacial and alluvial sediments. Investigations of a well-preserved flight of terraced sediments with good exposures at Capel Bangor, on the Afon Rheidol, mid-Wales, has allowed its Quaternary valley fill stratigraphy to be examined in detail. Study has revealed five terraced fills consisting of seven distinct sedimentary units. These range from Late Devensian ice-contact and ice-marginal deposits, to Holocene high-sinuosity stream sediments with episodes of man-induced accelerated deposition of fine-grained alluvium, and to aggradation and subsequent incision associated with historic metal mining. Examination of general sedimentary properties (e.g., granulometry, sedimentary structures, terrace surface morphology) show both differences in the pattern and controls of deposition and also progressive changes over Late Devensian and Holocene times. The sediments of the Rheidol Valley record the response and subsequent recovery of a drainage basin to glaciation, and the increasing influence of man on sediment yields, channel processes, and sediment quality.  相似文献   

Spectroscopic studies of X-ray binary pulsars     

F. Nagase 《Journal of Astrophysics and Astronomy》2002,23(1-2):59-65

Several new features of X-ray binary pulsars are revealed from recent observations with ASCA, RXTE, BeppoSAX and other X-ray observatories. Among these, I will review in this paper some recent progress in spectroscopic studies of accreting X-ray pulsars in binary systems (XBPs). First, I will discuss soft excess features observed in the energy spectra of XBPs and propose that it is a common feature for various subclasses of XBPs. Next I will present some recent results of high resolution spectroscopy with ASCA and Chandra.  相似文献   

Composite spectra paper 2: HD 88021/2     

R. Griffin 《Journal of Astrophysics and Astronomy》1988,9(4):193-203

HD 88021/2 (ADS 7662) is a very close visual binary. The accepted visual orbit, which is of very high eccentricity and graded “reliable”, led to the expectation of a periastron passage in 1981, when there should have been a large difference in radial velocity between the components. No such event took place, and there is little indication that it is likely to occur in the near future. A new interpretation of the visual orbital data leads to an orbit of a different character from those hitherto proposed. A decision between the competing orbits should be possible within a very few years. Meanwhile, the method of spectral subtraction developed in Paper 1 has enabled us to separate the spectra of the two components and to show that their spectral types are K0 III and A2m.  相似文献   

The association of poorly ordered graphite, coke and bitumens in greenschist facies rocks of the Poniklá Group, Lugicum, Czech Republic: the result of graphitization of various types of carbonaceous matter     

B. KRÍBEK  J. HRABAL    P. LANDAIS  J. HLADÍKOVÁ 《Journal of Metamorphic Geology》1994,12(4):493-503

Greenschist facies rocks of the Poniklá Group (Ordovician-Silurian), Czech Republic, contain several types of carbonaceous matter that differ in their morphology, texture, reflectance and Raman characteristics. The first type consists of large (up to 3 mm) irregularly bound particles of low reflectance (R_omin = 0.9%; R_omax = 5.6%). The area ratio of the 1585 cm^-1 to 1350 cm^-1 Raman peaks (1.08–1.17) indicates an intermediate degree of graphitization. The formation of this type of highly porous particle, displaying a texture reminiscent of regular or needle coke, is attributed to the thermal alteration of the amorphous (structureless) kerogen of the precursor sediments. The second type consists of lamellar particles up to 30 μm thick, which can be associated with the latter or can occur independently in white mica-rich laminae. This type is characterized by high bireflectance (R_omin = 0.6%; R_omax = 11.9%) and by lower ratios (0.70–0.82) of the Raman peak areas. These particles are interpreted as the product of solid-state, diffusion-controlled graphitization of a chemically homogeneous organic material, e.g. of graptolite periderms. The third type consists of isometric, up to 2 mm large, commonly fractured grains and fragments which mainly occur in quartz-rich laminae. In reflected light, the texture is either homogeneous or consists of various types of anisotropic mozaics. The Raman peak area ratios (0.75–1.14) indicate a highly variable degree of structural ordering. These particles are considered as the remains of metamorphosed bitumens, accumulated in the sandy laminae of the original sediments. The fourth type consists of small particles of carbonaceous matter (maximum length 25 μm, thickness 1-2 μm), which occur adjacent to crystal faces of white micas. This type is probably the product of epitaxial growth of graphite from the gaseous phase. The results of this work indicate that the differences in the degree of graphitization of the carbonaceous matter in low-grade metamorphosed rocks can be mainly related to the initial nature of the sedimentary organic matter and to its premetamorphic history.  相似文献   

DEDICATED PRINCIPAL PROPERTIES FOR PEPTIDE QSARS: THEORY AND APPLICATIONS     

BERTSKAGERBERG  MICHAEL  SVANTEWOLD 《地理学报(英文版)》1990,(3)

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Composite spectra     

R. F. Griffin 《Journal of Astrophysics and Astronomy》1990,11(4):491-505

A comprehensive survey of bright composite-spectrum binaries in the northern sky has provided so many radial-velocity data that orbits can now be determined for many objects whose orbits were hitherto unknown or else insecure or actually erroneous. Elements are given for the orbits of 30 such objects, thereby more than doubling the number of composite-spectrum binaries with known orbits  相似文献   

Oxide Mineralogy and Magnetic Properties of the Koidu Kimberlite Complex, Sierra Leone, West Africa     

S. E. Haggerty  R. B. Hargraves  L. A. Tompkins 《Geophysical Journal International》1990,100(2):275-283

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The calculated seismic properties of quartz mylonites with typical fabrics: relationship to kinematics and temperature     

David Mainprice  Martin Casey 《Geophysical Journal International》1990,103(3):599-608

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