共查询到20条相似文献，搜索用时 31 毫秒
1.
《中国地球化学学报》2006,25(B08):117-117
2.
4.
In nature selenate reduction and nitrate denitrification both follow a similar biogeo-chemical mechanism.It has been proved that abiotic stresses such as alternative drying and wetting can exert an important influence on nitrate denitrification as well as on selenate reduction.Our experimental results lend great support to the above conclusion. 相似文献
5.
《Comptes Rendus Geoscience》2018,350(5):195-201
To protect their steel structures from corrosion by cathodic protection, many harbours use aluminium sacrificial anodes, which induces aluminium release and potential contamination of the surrounding waters and sediments. To study the impact on Al mobility, a natural marine sediment was artificially contaminated with aluminium from different sources: sulphate or chloride salts, or sacrificial anodes. To estimate Al mobility in sediments, single (HCl) and sequential (F6) extractions were performed; they highlighted that aluminium is poorly mobile in natural sediment (HCl-leachable: 2% and F6-leachable: 9%). Contamination by aluminium salts inhibits HCl-leachability (≤ 2%), whereas the Al F6-leachability is intensified up to 18%, suggesting that the additional aluminium is scavenged in a mobile fraction that HCl is not able to solubilise. In case of aluminium anode contamination, sediments present surging Al HCl-leachable (15%) and F6-leachable (32%) fractions, which are related to aluminium mineralogical speciation. Indeed, contrary to the Al naturally present or introduced by salts, Al released by anodes is partly bound to the acid-soluble fraction, probably because of the integration of the released Al into the calcareous deposit produced at the anodes surfaces that finally comes away and gets mixed up with the sediment. The presence of aluminium in the acid-soluble fraction of sediments could have an important environmental impact as this fraction is easily available. Indeed, Al scavenged in the acid-soluble fraction of sediments participates in enhancing Al lability near the sacrificial anodes and may affect the surrounding ecosystems. 相似文献
6.
David A. BANKS 《《地质学报》英文版》2014,88(Z2):145-146
Please?refer?to?the?attachment(s)?for?more?details. 相似文献
7.
Sergey V. Kakareka Tamar I. Kukharchyk 《中国地球化学学报》2006,25(B08):177-178
In the paper the procedure for and results of a test study of a few persistent organic pollutants - polycyclic aromatic hydrocarbon （PAH）, polychlorinated biphenyls （PCB） and hexachlorobenzene （HCB） emission from the open burning of different types of wastes （domestic wastes, agricultural debris, landscape cleating debris, etc.） are discussed. The open burning of agricultural debris and landscape-clearing debris is widely applied in rural areas and small towns and in allotment gardens for the recovery of that part of wastes that can not be utilized for compost preparation. This process is most typical during the autumn season and to a lesser degree during spring. Burning occurs usually in bon fires. Burning modes differ depending on the volume of material burnt, the waste moisture content, the weather conditions, etc. During this process part of domestic wastes （polluted wood, paper, chipboard, films, plastics, etc.） are burned also. Investigations included the collection and preparation of combustible material, the simulation of open burning processes, particulate and gas emission sampling, chemical analysis of sample and data processing. Sampling procedures and sample preparation were agreeable to the emission sampling standards. The aerosol and vapour phases of POPs were collected by ordinary sampling train with pumping of waste gases through filter and solid sorbent （polyurethane foam）. For the measurements of PAH in emission, gas chromatography and mass spectrometry were used which make it possible to identify and determine 16 PAH compounds in the samples; this method was used for HCB determination also. Gas chromatography with ECD detector was used for PCB measurement. It was detected that the levels of PAH emission from wastes uncontrolled burning of wastes vary greatly. Influencing factors are composition and properties of refuse, temperature and mode of burning, level air supply. Generally, the increase of content of wood leads to the increase of PAH in emission. PAH emission also increased with increasing temperature of burning. The highest PAH values are characteristic of emissions from domestic refuse burning. Practically, all naphthalene, acenaphthylene, acenaphthene （from 60% to 100% of their total mass） and fluorene （14%-99%） were emitted in gaseous form. 相似文献
8.
On the basis of the one-dimension infinite element theory, the coordinate translation and shape function of 3D point-radiate 8-node and 4-node infinite elements are derived. They are coupled with 20-node and 8-node finite elements to compute the compression distortion of the prestressed an- chorage segment. The results indicate that when the prestressed force acts on the anchorage head and segment, the stresses and the displacements in the rock around the anchorage head and segment con- centrate on the zone center with the anchor axis, and they decrease with exponential forms. Therefore, the stresses and the displacement spindles are formed. The calculating results of the infinite element are close to the theoretical results. This indicates the method is right. This article introduces a new way to study the mechanism of prestressed anchors. The obtained results have an important role in the re- search of the anchor mechanism and engineering application. 相似文献
9.
Alexander Likhoshvay Mikle Grachev 《中国地球化学学报》2006,25(B08):138-139
We investigated in more detail the adsorption phenomenon which was described earlier. It was clearly established that the hydroxyl apatite was not participated in P adsorption. This phenomenon takes place because of ferric hydroxide film. Modem sediments from the Southem Basin of Lake Baikal were taken and stirred with Baikal water. Carrier-free [^32p]-orthophosphate was added in this system. Similar experiments were made with carrier-free [^35S]-sulphate. Sulphate stayed in supematant completely. The influence of pH on the system with inorganic phosphate was also studied. In low alkali conditions phosphate migrated in supematant, in low acid, in sediments. Baikal sediment was stripped of iron-hydroxous film by treatment with 1% oxalic acid. Investigation of striped sediment shown that phosphate stays in supematant only. Hence, hydroxyl apatite cannot be the phase of the sediments of Lake Baikal which binds phosphate. This all showed by our group before. Now we have found the limit of phosphate sorption in Lake Baikal sediments and the stehiometry of the sorption. The sorption limit of Lake Baikal sediments was studied. An experiment with inorganic ^31P phosphate was made. 0.025% K2HPO4 solution with adding ^32P radioactive mark into it was prepared. 100 μL of mixture of ^31PO4^3- and ^32PO4^3- seven times were added in a ＂Baikal water-Baikal sediment＂ system and blank （100 ml BW only）. Concentrations of inorganic ^31PO4^3- were very low so the bend dot on the diagram was found and sorption limit of sediment was estimated. Baikal sediment stopped assimilating phosphate in the bend dot. The stehiometry of sorption was estimated by supematant-sediment radioactive ratio, which equals 3, that is, three Fe （Ⅲ） atoms associate one PO4^3- anion. The only Fe （Ⅲ） substance which could associate P is -Fe-O-Fe- polymer film. It also dissolves in acid conditions. 相似文献
10.
《Applied Geochemistry》1988,3(5):441-453
Green River shale (Type I kerogen), Yaamba shale (Type II kerogen) and Sarufutsu coal (Type III kerogen) were heated to various temperatures using Rock-Eval. The amount of hydrocarbons generated and weight loss by pyrolysis were measured to obtain a better understanding of petroleum generation. After the pyrolysis experiments, elemental analysis (C, H), vitrinite reflectance (%Ro) measurement, maceral observation, infrared spectroscopy (IR) and13C-NMR spectroscopy were carried out on the coal samples. Changes in H/C atomic ratio, IR and NMR spectra indicate that experiments by Rock-Eval resemble those of the natural evolution of kerogen. However, the petrographic changes of the coal show more similarity to coal liquefaction and coking than to natural coalification. Changes in the amount of generated hydrocarbons with increasing maturation show that Type II kerogen produces more hydrocarbons than does Type I when Ro does not exceed 1.1%. Petroleum generation curves for the three samples were concordant with trends in natural systems, and a conceptual model of petroleum generation curve classified into three types is proposed, namely (1) curve of total amount enerated, (2) curve of generation rate, and (3) curve of fluid composition. Changes of IR and NMR spectra after pyrolysis imply that generated hydrocarbons are derived from aliphatic C structures of kerogen macromolecules. Moreover, the difference in genetic potential between Type I and Type III reflects different amounts of aliphatic structures. Type I is assumed to have a simple assemblage (mainly polymethylene carbons), and Type III is assumed to have a more complex variety of structures that are responsible for the difference in generation rates between the two kerogen Types. A quantitative analysis of C species of various bond structure by13C-NMR confirms that petroleum generation is the process of bond cleavage of kerogen macromolecules; lower-energy bonds decrease at an earlier stage of reaction, while aromatic carbons with higher bond energies survive to form graphitic structure at postmature stages. Emphasis is placed on the idea that the most important and direct factor in petroleum generation is a change in the molecular structure of kerogen with increasing maturation. NMR and other methods providing information about molecular structures of kerogen will become strong tools for evaluating source rocks and sedimentary basins in the future. 相似文献
11.
Lü Guxian 《中国地质大学学报(英文版)》2004,15(2):162-166
An experimental study of the confining pressure, i.e. additional hydrostatic pressure initiated by the tectonic force is presented. The experimental progress is that the σ1 is gradually increasing from 0 in a limiting movement (ε1=0) in the σ1 direction and the speed rate of the accelerating load is 0.4 MPa*s-1 in the lateral and level directions. When σ2=σ3<200 MPa, Δσl is nearly lacking, Δσl is increasing at a high speed only when the horizontal force reaches 250-380 MPa, and Δσl almost ceases to increase at the level force of 380 MPa. It is calculated that the tectonic force can produce the confining pressure which is gradually increasing with σ2=σ3 before it reaches 380 MPa in an experiment. It is supposed that the horizontal force is almost all transformed into the confining pressure with the increase of the creep deformation of rocks. 相似文献
12.
Leah I. Bendell-Young 《中国地球化学学报》2006,25(B08):72-72
Bivalves （mussels, scallops, oysters）, from the Pacific Northwest coast of British Columbia, Canada, contain high levels of cadmium, in some cases exceeding 7 μg/g wet weight of tissue. We have for the past 5 years, attempted to determine the source of this cadmium to these filter-feeding invertebrates, with our objective being that we would then be able to advise where bivalves could be cultured for human consumption such that cadmium accumulation by the bivalve was minimized. Our studies have indicated that there are distinct regional and temporal variations in bivalve cadmium residues. Some patterns in cadmium accumulation did occur, e.g. for bivalves located on the most outer westcoast of British Columbia, cadmium residues demonstrated some seasonal dependence. In general, however, variations could not be readily ascribed to food sources （oceanic versus terrestrial）, or to abiotic factors such as salinity and turbidity. Cadmium residues in oysters were negatively correlated with temperature supportive of a seasonal influence on measured cadmium concentrations. 相似文献
13.
Shengli WANG 《中国地球化学学报》2006,25(B08):124-125
Heavy metals in soils may adversely affect environmental quality. This paper studied the influence of copper concentration, pH, temperature, and the ratio of solid to solution on the desorption of Zn in kaolin from Suzhou, China in a background solution of 0.01M CaC12 by batch extraction experiments. At 0, 5, 50, 100 mg/L Cu concentrations, for each 0.5, increase in pH between about 1.80 and 3.04 percent desorption decreasing by 3.80%, 13.87%, 9.97%, and 7.65%, respectively. The pH 50 （ pH at 50% Zn desorption） was found to follow the sequence of Cu （5mg/L, pH 50=2.60）. 相似文献
14.
V. V. Pipin 《Astronomy Reports》2007,51(5):411-420
We consider a solar dynamo mechanism that generates large-scale magnetic fields due to the combined action of cyclonic flows (the α effect), differential rotation (the Θ effect), and the non-uniformity of large-scale magnetic fields (the Θ × J effect). Our results are based on numerical model which takes into account currently available data on the differential rotation of the convection zone and the intensity of convective flows in the solar interior. A reasonable choice of parameters characterizing the intensity of magnetic-field generation by the α and Θ × J mechanisms can account for an oscillatory dynamo regime with properties similar to the 22-year magnetic-activity cycle of the Sun. We analyze the nonlinear saturation of the generation effects in the large-scale magnetic field, due to either magnetic stresses or the conservation of magnetic helicity. Allowance for the helicity of the small-scale magnetic fields is of crucial importance in limiting the energy of the generated large-scale magnetic field. 相似文献
15.
Doklady Earth Sciences - Flares for combustion of associated petroleum gas (APG) are the main sources of thermal impact on landscapes during the exploitation of oil deposits. The object of this... 相似文献
16.
17.
Recently impregnated diamond bits have been widely applied in drilling hard and me-dium-hard formations in the world.It is quite necessary to study the fracturing mecha-nism of the impregnated diamond bit and the classification of rocks,which can realizeoptimum drilling.Using multi-parameter rotary test stand can monitor and print nineparameters.The diamond size and concentration for experiment are various and there arenearly200 types of samples,numbering over1000 pieces.The results of laboratory arethe same as those in the field.Besides,this paper expresses that the diamond concentra-tion of impregnated diamond bits effect the bonding strength of diamond imbedded in ma-trix.During drilling by impregnated diamond bits three ways are used to cool the bits.The contact area between impregnated diamond layer and flow,and the drilling flowthrough annulus carrying away heat with conduction form can be shown by equations.Itis impossible to classify the rock drillability only by using single factor.The best met 相似文献
18.
19.
Oishi ShujiDepartment of Environmental Science Technology Faculty of Engineering Shinshu University Wakasato Nagano - JapanYamamoto HirofumiDepartment of Chemistry Material Engineering Faculty of Engineering Shinshu University 《中国地质大学学报(英文版)》2002,13(1):35-39
Well-formed crystals of emerald, Be3AI2Si6O18:Cr, were easily grown from an Na2O-MoO3 flux by an isothermal technique. The crystal growth was conducted by heating a mixture of solute and flux at 1 100 ℃ for 24 h. The evaporation loss of flux depended on the amount of Na2O added to MoO3. Emerald crystals of lengths up to 2.1 mm and widths of 1. 4 mm were grown. The crystal sizes were dependent on the evaporation loss of the flux. The obtained crystals were transparent and exhibited the typical emerald-green color. The form of the emerald crystals was a twelve-sided prism bounded by well-developed faces. The aspect ratios were in the region of 1. 4 to 2. 3. The density was (2. 64±0.02) g/cm3. The IR absorption bands were in good agreement with the literature data. 相似文献
20.
Tishkov A. A. Tsarevskaya N. G. Novenko E. Yu. Belonovskaya E. A. 《Doklady Earth Sciences》2021,499(2):686-692
Doklady Earth Sciences - The problems of diagnostics of the beginning of agrarian development of coniferous–broad-leaved forests in northwestern European Russia and its specificity regarding... 相似文献