S. Falsaperla  S. Alparone  S. D'Amico  G. Di Grazia  F. Ferrari  H. Langer  T. Sgroi  S. Spampinato 《Pure and Applied Geophysics》2005,162(12):2583

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Relationship between rank and distribution of methylaromatic hydrocarbons for condensates of different origins     

P. Garrigues  J. Connan  E. Parlanti  J. Bellocq  M. Ewald 《Organic Geochemistry》1988,13(4-6)

Aromatic hydrocarbon fractions from thirty gas condensates have been analysed by capillary GC and high resolution Shpol'skii spectroscopy for the determination of the relative distribution in methylphenanthrene (MP), dimethylphenanthrene (DMP) and methylpyrene (MPy) series. The measured maturity indices, MPI, DMPI and MPyI which appeared previously suitable for rocks, coals and crude oils have been tested for the recognition of rank levels of condensates. MPI and DMPI exhibit a remarkedly similar evolution which allows the differentiation of the samples analysed in these works. Such studies extend the applicability of alkylaromatic hydrocarbon ratios to the characterization of maturity level of condensates which range from immature-marginally mature to overmature samples, partially biodegraded or not.  相似文献   

The role of engineering geology for planning and construction of underground openings: Introduction of the symposium 19-3 “engineering geology in the utilization of underground space”, 29th Int. geological congress, Kyoto, Japan 1992     

Michael Langer 《Engineering Geology》1993,35(3-4):143-147

Langer, M., 1993. The Role of Engineering Geology for Planning and Construction of Underground Openings. In: M. Langer, K. Hoshino and K. Aoki (Editors), Engineering Geology in the Utilization of Underground Space.Eng. Geol., 35: 143–147.  相似文献   

Safety concept and criteria for hazardous waste sites     

M. Langer 《Engineering Geology》1993,34(3-4):159-167

The problem of waste disposal in Germany has been solved by using a combination of above-ground and underground disposal. Site selection criteria and precise criteria for the performance assessment of various types of waste disposal are available. In view of long-term safety of disposal, it is necessary to include geological and hydrogeological viewpoints in addition to purely engineering viewpoints.

In particular, the geotechnical site-specific safety assessment is described, as defined by the government in “Technical Regulations on Wastes” (TA-Abfall) in the section “Underground Disposal”. This safety assessment must cover the entire system comprising waste, cavern/mine and surrounding rock. For this purpose geo-mechanical models have to be developed.

According to the multi-barrier principle, the geological setting must be able to contribute significantly to isolation of the waste over longer periods. The assessment of the integrity of the geological barrier can only be performed by making calculations with validated geomechanical models.

Various engineering geological data are required for the selection of a site, for the design and construction of a repository, and for a safety analysis for the post-operational phase. These data can only be attained by the execution of a comprehensive site-specific geomechanical exploration and investigation program. The planning and design of an underground repository in rock salt layers are described, as an example for the various steps of this type of safety assessment.  相似文献   

Polarized electronic absorption spectra of 3d3-configurated tetravalent manganese in octahedral fields of Mn(SeO3)2     

M. Wildner  K. Langer 《Physics and Chemistry of Minerals》1994,21(5):294-298

Polarized optical absorption spectra of Mn(IV) in octahedral crystal fields of Mn(SeO₃)₂ have been studied by means of microscope-spectrometry in the range 40000-4000 cm^?1 and at temperatures between 113 K and 293 K. Intense charge-transfer absorptions (linear absorption coefficient α ? 30000 cm^?1) completely mask the d-d transitions in the UV and VIS region above ≈23000 cm^?1. The optical electronegativity χ _opt of Mn(IV) in Mn(SeO₃)₂ is estimated to be 2.7. In accordance with the d ₃ configuration of tetravalent manganese three d-d bands observed at ambient temperatures at 13250, 14137 (α≈50 cm^?1) and ≈18500 cm^?1 (α≈500–800 cm^?1) are assigned to the spin forbidden ⁴ A _2g →² E _g and ⁴ A _2g →² T _1g transitions as well as to the first spin allowed ⁴ A _2g →⁴ T ^2g transition, respectively. These assignments allow the calculation of the following ligand field parameters: Dq ≈ 1850 cm^?1, B ₅₅ = 869 cm^?1 (β ₅₅ = 0.82), and C = 2346 cm^?1 (293 K).  相似文献   

Polarized single-crystal FTIR-spectra of natural staurolite     

Monika Koch-Müller  Klaus Langer  Anton Beran 《Physics and Chemistry of Minerals》1995,22(2):108-114

Polarized infrared absorption spectra of thin single-crystal slabs parallel to (010) and (001) of a staurolite from Pizzo Forno, Ticino, with analyzed composition (Fe_2.9Mg_0.9Zn_0.1Mn_0.1)Al_17.5Ti_0.1(Si_7.7Al_0.3)O₄₈H₃ have been measured in the range of 3000–4000 cm^?1. From the pleochroitic behaviour of the OH-vibrations three groups of bands can be distinguished: the bands of group I, a strong band at 3445 cm^?1 plus a weak shoulder at 3358 cm^?1, and the bands of group II, a weak band centered at 3677 cm^?1 plus a shoulder at 3635 cm^?1, are assigned to the H1 and H2 protons, respectively. The bands of group III, a weak band at 3577 cm^?1 plus a shoulder, cannot be interpreted on the basis of the proton positions known so far. We assign them to an additional proton H3, which is bonded to O1 and shows a bifurcated hydrogen bridge to two O5 in a vacant T2 site.  相似文献   

Crystal field spectra and jahn teller effect of Mn3+ in clinopyroxene and clinoamphiboles from India     

S. Ghose  M. Kersten  K. Langer  G. Rossi  L. Ungaretti 《Physics and Chemistry of Minerals》1986,13(5):291-305

Blanfordite (I), winchite (II), and juddite (III), all showing vivid colors and pleochroism, from highly oxidized parageneses of Indian gondites were studied by microprobe, Mössbauer, and microscope-spectrophotometric techniques and by X-ray structure refinements. The compositions of the Mn-bearing minerals were close to diopsideacmite (I) and magnesio-arfvedsonite to magnesio-riebeckite (II and III). Transition metal ions are located inM(1)-octahedra (I) or predominantlyM(2)-octahedra (II, III). Mössbauer spectra of⁵⁷Fe(IS, ΔE _Q) are typical of octahedral Fe³⁺ only. Polarized absorption spectra in the UV/VIS/NIR ranges explain color and pleochroism of the minerals. The position of the UV-“edge” is correlated with Fe³⁺-contents of the minerals, except for judditeE ∥Z, where the edge shows an unusual low energy position. This is most likely due to Mie-scattering of submicroscopic inclusions of braunite with nearly uniform dimensions. In the VIS range, the spectra are dominated by a complex band system between 15,000 and 20,000 cm^?1. Energies and ?-values of component bands are compatible with those of Mn³⁺ d-d transitions in other Mn³⁺-bearing silicates. The polarization behavior of component bands can best be explained by aC ₂(C2″) symmetry of the crystal field. The Jahn-Teller splitting (<9,000 cm^?1) of the⁵ E _g ground state of Mn³⁺ inO _h crystal fields is appreciably smaller than in other Mn³⁺-silicates. Crystal field parameters 10Dq, (I) 13,650, (II) ca. 11,640, and (III) 11,925 cm^?1, are near to that in piemontite. The crystal field stabilization energy of Mn³⁺, (I) 146, (II) ca. 140, (III) 142 \({{{\text{kJ}}} \mathord{\left/ {\vphantom {{{\text{kJ}}} {\text{g}}}} \right. \kern-0em} {\text{g}}}{\text{ - atom}}_{{\text{Mn}}^{{\text{3 + }}} } \) , is appreciably smaller than that found in other Mn³⁺-silicates (piemontites and manganian andalusites, viridines and kanonaite).  相似文献   

Structural locations of the iron ions in cordierite: a spectroscopic study   总被引：1，自引：0，他引：1  

Vladimir M. Khomenko  Klaus Langer  Charles A. Geiger 《Contributions to Mineralogy and Petrology》2001,141(4):381-396

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Electronic absorption spectra of Fe2+ ions in oxygen-based rock-forming minerals at temperatures between 297 and 600 K     

M. N. Taran  K. Langer 《Physics and Chemistry of Minerals》2001,28(3):199-210

 Polarized electronic single crystal spectra of natural Fe²⁺ ion-bearing oxygen-based minerals, in which ferrous ions enter octahedral sites of different symmetry and distortion (olivine, cordierite, ortho- and clinopyroxene, amphibole), eightfold sites in garnet (almandine) and clinopyroxene (M2), and tetrahedral sites in spinel, were studied at temperatures from 300 to ca. 600 K. In the minerals studied, the spin-allowed bands of Fe²⁺ display rather variable temperature behaviour. In most cases, due to the thermal expansion of the Fe²⁺-bearing polyhedra, bands shift to lower energies upon increasing temperature, though there are some exceptions to this rule: in cases of other than sixfold octahedral or close to octahedral coordination, in almandine and spinel the bands shift to higher energies, which can be explained by an increase in distortions of the Fe²⁺-bearing polyhedra. Splitting of the excited ⁵ E _g-level of Fe²⁺ ions usually, but not always, increases with temperature, reflecting thermally induced increase in distortion of the Fe²⁺-bearing sites in the minerals studied. Integral intensities of the bands in question do not always obey the general rule, according to which intensity should increase with temperature, when the 3d ^N-centred site is centrosymmetric, or should remain unchanged when the 3d ^N site lacks an inversion centre. The experimental results show that the response of the characteristics of absorption bands such as width, intensity and energy caused by dd transitions of Fe²⁺ in oxygen-based minerals to increasing temperature is not always uniform and is at variance with expectation. This temperature dependence cannot be used directly to solve band assignment problems, as earlier proposed in the literature. Received: 22 December 1999 / Accepted: 30 October 2000  相似文献   

Polarized single crystal spectra of natural and reheated olivines in the near ultraviolet spectral region and the problem of Fe3+-bearing structural defects     

M. D. Dyar  V. Kahlenberg  K. Langer  H. Terzenbach 《Physics and Chemistry of Minerals》1996,23(4-5):285-286

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