断面法在护岸工程土方量计算中的应用     

石力  龙勇  李仁忠 《测绘与空间地理信息》2017,(1)

断面法在土方量计算中具有广泛的应用。本文提出了在护岸工程中只计算中线单侧的土方量的方法,结合重庆市合川城区防洪护岸综合整治二期工程(东津沱段)项目进行实践。结果表明,该方法简单有效,为实际应用者提供了有效的计算方法。  相似文献   

Hydrogen Incorporation in Crystalline Jadeite: Insight from First Principles Calculations     

ZHANG Xiaoling  FAN Xiaoyu  MENG Dawei  WU Xiuling  LIU Weiping 《《地质学报》英文版》2016,90(3):939-945

Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects in jadeite by the plane-wave pseudo-potential method based on density functional theory, and optimized the atomic positions and lattice constants in all configurations(different defective systems). Incorporation mechanisms considered for hydrogen(H) in jadeite include:(1) hydrogen incorporating with the O2 site oxygen and coexisting with M2 vacancy;(2) one H atom combined with an Al atom replacing Si in tetrahedron;(3) 4H atoms directly replacing Si in tetrahedron and(4) 3H atoms replacing Al on the M1 site. The four incorporation mechanisms mentioned above form the corresponding V_(Na)-H_i, Al_(Si)-H_i, V_(Si)-4H_i and V_(Al)-3H_i point defects. The molecular dynamics simulation to the ideal, V_(Na)-H_i, Al_(Si)-H_i, V_(Si)-4H_i and V_(Al)-3H_i point defects under the P-T conditions of 900 K, 2 GPa, the V_(Na)-H_i and Al_(Si)-H_i point defects under different pressures at T = 900 K, and Al_(Si)-H_i point defects under different temperatures at P = 3 GPa was performed to examine the preferential mode of hydrogen incorporation in jadeite by means of first-principles calculations. The calculations show that the averaged O–H bond-length in the hydrogen point defects system decreased in the order of Al_(Si)-H_i, V_(Na)-H_i, V_(Si)-4H_i and V_(Al)-3H_i. V_(Na)-H_i complex defects result in a contraction of the jadeite volume and the presence of Al_(Si)-H_i, V_(Si)-4H_i and V_(Al)-3H_i defects could increase the supercell volume, which is the most obvious in the V_(Al)-3H_i defects. The energy of formation of Al_(Si)-H_i and V_(Al)-3H_i complex defects was much lower than that of other defect systems. The V_(Al)-3H_i defects system has the lowest energy and the shortest O–H bond-length, suggesting that this system is the most favorable. The analytical results of vacancy formation energy, O–H bondlength, and the stability of the hydrogen defects in jadeite have suggested that the preferred hydration incorporation mode in jadeite is V_(Al)-3H_i complex defect.  相似文献   

Quantitative estimation of petroleum prospect outcome probabilities: an overview of procedures     

John W. Harbaugh 《Marine and Petroleum Geology》1984,1(4):298-312

Estimation of prospect outcome probabilities in numerical form should be a central objective for petroleum geologists. Most numerical estimates of outcome probabilities represent subjective guesses. While the effectiveness of subjective procedures is difficult to gauge, several postmortem analyses suggest that subjective procedures are ineffective. Objective procedures for estimating outcome probabilities should yield much improved estimates. Objective procedures require that geological, geophysical and production data be organized so that geological and geophysical characteristics of prospects interpreted before they were drilled can be compared systematically with outcomes of prospects after they have been drilled. An example application that involves well data and an example application that involves seismic data demonstrate that objective procedures are simple in principle, but require organization of information in a form suitable for computation of frequencies, on which objective estimates of probabilities can be based.  相似文献   

土地开发整理项目中土方量计算的精度分析   总被引：1，自引：0，他引：1  

樊彦国  侯春玲  张磊 《测绘科学》2009,34(6)

土方量计算是土地开发整理项目中土地平整工程的重要组成部分,其工程量的大小直接影响着工程的预算及投资。本文通过建立理想模型,对土方量的计算精度进行了分析、探讨。并以国家投资重点项目——山西省隰县土地开发整理项目为例进行示范研究,通过分析对提高土方量计算精度提出了一些观点和建议。  相似文献   

The dependence of the concentration of OH on its precursors under moderately polluted conditions: A model study   总被引：1，自引：0，他引：1  

D. Poppe  M. Wallasch  J. Zimmermann 《Journal of Atmospheric Chemistry》1993,16(1):61-78

Oxidation of trace gases emitted into the atmosphere is frequently promoted by free radicals. During daytime, the most important radical is the hydroxyl radical, since it reacts with almost all pollutants thereby initializing their ultimate removal from the atmosphere. Since the reaction with OH is in many cases the rate-determining step, the ambient OH concentration is a measure for the atmosphere's oxidation capacity. This paper investigates the influence of the chemical precursors and the photolysis frequencies on the atmospheric OH abundance under moderately polluted and rural conditions. The dominant controlling parameter are the photolysis of ozone and the concentrations of the nitrogen oxides.  相似文献   

Porphyry Cu–Au mineralisation associated with a multi-phase intrusion, and related replacement fronts in limestones in an island arc setting near the Gümü hane village (Artvin) in the Eastern Black Sea Province (Turkey)     

Mi ra Akay   mer Gündüz 《Chemie der Erde / Geochemistry》2004,64(4):359-383

The Gümü hane area near Artvin is highly characteristic due to a significant hydrothermal alteration zone genetically associated with a microdiorite stock and its late-stage derivatives in the form of porphyry plugs that intruded into all the pre-Middle Eocene lithologies. The porphyry intrusion is multi-stage, intermediate to felsic in composition, and divided into pre-ore feldspar porphyries and quartz–feldspar porphyries, syn-ore feldspar–amphibole porphyries, and post-ore feldspar porphyries. Sericitic alteration is dominant, but K-silicate alteration is also observed and is characterised mainly by secondary feldspars, biotites, quartz, anhydrite, magnetite and pyrite veinlets. The central part of the alteration and the porphyry system where syn-ore feldspar–amphibole porphyry outcrops coincides with intense quartz stock-working with anomalous but uneconomical Cu and Au values. In this zone, pyrite is ubiquitous and is accompanied by chalcopyrite and lesser sphalerite, sulphosalts, molybdenite, bornite and magnetite. Chemical analyses of surface and drill core samples show that overall Au and Cu values are around 0.5 ppm and 0.3%, respectively, and that they are in the ranges of 1–2 ppm and 0.3–0.4%, respectively, in the densest stock-work zones.Multi-phase intrusion of porphyries into Late Cretaceous limestone also caused replacement fronts along re-crystallised limestone and porphyry contacts. This type of mineralisation is enriched in Mn, Zn, Cu, Au and Ba, and contains on average 4.7% MnO, 3.2% FeO, 3.1% Zn, 0.95% Cu, 0.3% Pb, 200 ppb Au, 900 ppm Bi and 660 ppm Ba, present in Fe- and Mn-oxides, pyrite, chalcopyrite, sphalerite and lesser bornite, sulphosalts and gold. Supergene oxidation is well developed in these zones.Hydrothermal alteration mass change calculations reflect an intimate relationship between the two types of mineralisation. The lithologies near mineralised fronts are highly depleted in MnO and Zn, and the intensity of depletion is reduced away from the contact into the porphyry. The leached elements are added to the re-crystallised limestone block in which MnO and Zn show an 81-fold and 472-fold increase, respectively, over the least altered limestone. Au and Cu are enriched along the contact both in the porphyry and in the limestone, implying that they may have been derived either from other lithologies in the vicinity or the magma itself.  相似文献   

工程土方量计算比较分析   总被引：20，自引：0，他引：20  

罗德仁邹自力  汤江龙 《华东地质学院学报》2005,28(1):59-64

土方计算的基本方法有断面法、方格网法、等高线法及基于数字高程模型(DEM)法。在实际生产应用中，不同的方法计算的同一场地土方量数量相差较大，所以不同方法土方计算精度不同，适用范围也不一样。本文基于对工程土方量计算中的断面法、方格网法、等高线法及基于数字高程模型(DEM)法的基本原理、方法和优缺点比较分析。从理论上讨论它们的适用范围、条件及精度分析。结果表明，DEM法适用于所有场地，且精度较高，方格网法只适用于平坦场地；断面法适用于特别复杂的狭长带状地形场地。  相似文献   

An internally consistent dataset with uncertainties and correlations: 3. Applications to geobarometry, worked examples and a computer program   总被引：31，自引：4，他引：31  

R. POWELL  T.J.B. HOLLAND 《Journal of Metamorphic Geology》1988,6(2):173-204

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Forbidden transition probabilities of astrophysical interest among low-lying states of V III     

Andrei Irimia 《Journal of Astrophysics and Astronomy》2007,28(2-3):157-166

Electric and magnetic multipole transitions among low-lying states of doubly ionized vanadium were computed using the multi-configuration Hartree-Fock (MCHF) method with Breit-Pauli (BP) corrections to a non-relativistic Hamiltonian. Energy levels were determined up to and including 3d ²(¹ G)4s b ² G _7/2 and computed energies were found to be in good agreement with experiment and other theories. In addition to Einstein A _ki coefficients for some E2 and M1 transitions, lifetime data and selected weighted oscillator strengths are also reported.  相似文献   

High-pressure properties of diaspore,AlO(OH)     

A. Friedrich  D. J. Wilson  E. Haussühl  B. Winkler  W. Morgenroth  K. Refson  V. Milman 《Physics and Chemistry of Minerals》2007,34(3):145-157

The structural compression mechanism and compressibility of diaspore, AlO(OH), were investigated by in situ single-crystal synchrotron X-ray diffraction at pressures up to 7 GPa using the diamond-anvil cell technique. Complementary density functional theory based model calculations at pressures up to 40 GPa revealed additional information on the pressure-dependence of the hydrogen-bond geometry and the vibrational properties of diaspore. A fit of a second-order Birch–Murnaghan equation of state to the p–V data resulted in the bulk modulus B ₀ = 150(3) GPa and B ₀ = 150.9(4) GPa for the experimental and theoretical data, respectively, while a fit of a third-order Birch–Murnaghan equation of state resulted in B ₀ = 143.7(9) GPa with its pressure derivative B′ = 4.4(6) for the theoretical data. The compression is anisotropic, with the a-axis being most compressible. The compression of the crystal structure proceeds mainly by bond shortening, and particularly by compression of the hydrogen bond, which crosses the channels of the crystal structure in the (001) plane, in a direction nearly parallel to the a-axis, and hence is responsible for the pronounced compression of this axis. While the hydrogen bond strength increases with pressure, a symmetrisation is not reached in the investigated pressure range up to 40 GPa and does not seem likely to occur in diaspore even at higher pressures. The stretching frequencies of the O–H bond decrease approximately linearly with increasing pressure, and therefore also with increasing O–H bond length and decreasing hydrogen bond length. Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.  相似文献