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941.
Cathleen E. McGinnis Jinesh C. Jain Clive R. Neal 《Geostandards and Geoanalytical Research》1997,21(2):289-305
High sensitivity and low detection limits would seem to make inductively coupled plasma-mass spectrometry (ICP-MS) an ideal analytical tool for determining low (sub-μg g-1 ) concentrations of the rare earth elements (REE), Y, Zr, Nb, Hf, Ta, Sn, W, Mo, Th, and U in most mafic materials (e.g. Hall and Plant 1992). However, the generally "sticky" nature exhibited by most of the high field strength elements (HFSEs: Zr, Nb, Hf, Ta, Th and U) as well as Sn, W and Mo can result in spurious results due to memory effects transmitted between unknowns and calibration samples. This, in turn, can seriously compromise the sensitivity, accuracy, and precision of ICP-MS analyses for these elements in geological materials. Data resulting from analyses with poor accuracy and precision can lead to erroneous interpretation and misleading petrogenetic modelling. To resolve this problem, we propose an effective wash protocol for these critical trace elements. 相似文献
942.
W. Bae D. Han E. Kim R. A. de Toledo K. Kwon H. Shim 《International Journal of Environmental Science and Technology》2016,13(7):1675-1684
The upflow anaerobic sludge blanket process followed by the biological aerated filter process was employed to improve the removal of color and recalcitrant compounds from real dyeing wastewater. The highest removal efficiency for color was observed in the anaerobic process, at 8-h hydraulic retention time, seeded with the sludge granule. In the subsequent aerobic process packed with the microbe-immobilized polyethylene glycol media, the removal efficiency for chemical oxygen demand increased significantly to 75 %, regardless of the empty bed contact time. The average influent non-biodegradable soluble chemical oxygen demand was 517 mg/L, and the average concentration in effluent from the anaerobic reactor was 363 mg/L, suggesting the removal of some recalcitrant matters together with the degradable ones. The average non-biodegradable soluble chemical oxygen demand in effluent from the aerobic reactor was 87, 93, and 118 mg/L, with the removal efficiency of 76, 74, and 67 %, at 24-, 12-, and 8-h empty bed contact time, respectively. The combined anaerobic sludge blanket and aerobic cell-entrapped process was effective to remove the refractory compounds from real dyeing wastewater as well as in reducing organic loading to meet the effluent discharge limits. This integrated process is considered an effective and economical treatment technology for dyeing wastewater. 相似文献
943.
Using microprobe laser-desorption, laser-ionization mass spectrometry (μL2MS), we measured the distributions of alkylated and unalkylated polycyclic aromatic hydrocarbons (PAHs) in the free organic material of 20 carbonaceous chondrites. These meteorites represent a variety of meteorite classes and alteration histories, including CI, CK, CM, CO, CR, CV, and Tagish Lake. This work provides information on free organic compounds that is complementary to studies of the structure and composition of meteoritic macromolecular content.For the nine CM2 meteorites analyzed, we observe that higher relative abundances of alkylated PAHs correlate with more intense aqueous activity. We attribute this correlation to the differences in solubility and volatility between unalkylated and alkylated PAHs. Naphthalene and its alkylation series are more susceptible to the effects of aqueous exposure than the less-soluble PAH phenanthrene and its alkylated derivatives. These observations are consistent with the possibility of chromatographic separations on the meteorite parent bodies. We identify six CM2 meteorites with similar PAH distributions that may represent the original, unaltered organic composition of the parent body.Increased metamorphic intensity reduces the abundance of all PAHs. The thermally metamorphosed CK chondrites had no detectable levels of typical meteoritic PAHs. This observation might be explained either by a loss of PAHs caused by volatilization or by a significantly different organic content of the CK parent body. 相似文献
944.
Zoning of diamonds from the Mir kimberlite pipe: Results of Fourier-transformed infrared spectroscopy 总被引:1,自引:0,他引:1
Plates prepared of diamonds from the Mir kimberlite pipe were examined with FTIR spectroscopy. It is shown that B1 defects were formed by annealing during crystal growth, whereas B2 centers arose after growth cessation. The development of B2 centers in a natural diamond is the secondary process with respect to the aggregation of the nitrogen admixture. The kinetics of this process is related to the breakdown of an oversaturated solid solution. The results obtained make it possible to estimate the temperature and duration of natural diamond growth. 相似文献
945.
Richard H. Pierce Charles E. Olney George T. Felbeck 《Geochimica et cosmochimica acta》1974,38(7):1061-1073
A procedure was devised to study pp′-DDT [2,2-bis()-1,1,1-trichloroethane] adsorption and desorption to suspended particulates in aqueous solutions. DDT adsorption to a marine sediment, sediment fractions, clay and humic acid suspended in sea water was investigated and the humic fraction was found to have a greater adsorbing capacity than the clay or sediment. Removal of the humic fraction from sediment reduced the adsorption capacity to less than 60 per cent of the original sediment sample. It was concluded that suspended humic particulates may be important agents for transporting chlorinated hydrocarbons through the water column and for concentrating them in sediments and in detritus-feeding organisms. 相似文献
946.
D.E. Grandstaff 《Geochimica et cosmochimica acta》1977,41(8):1097-1103
The kinetics of bronzite orthopyroxene dissolution were investigated in HClKCl solutions having a total concentration of 0.1 M, over the pH range 1–4.5, at temperatures between 42 and 1°C. Dissolution of the pyroxene was incongruent and followed a parabolic rate law. The activation energy of the reaction is 10.5 ± 0.6 kcal mole?1. The rate dependence on hydrogen ion activity is one-half order. The rate of dissolution is unaffected by substitution of sodium for potassium, or sulfate or nitrate for chloride anion, or by addition of citrate or acetate ions. However, traces of fluoride increase the dissolution rate. The rates observed are one to two orders of magnitude slower than those previously reported by Luceet al. (1972) for dissolution of enstatite. 相似文献
947.
As previously found for a chondritic inclusion of unknown affinity, mineralogic and petrologic properties of 9 inclusions in the Cumberland Falls enstatitc achondrite are primitive members of the forsterite (F) chondrite group, hitherto defined by 4 meteorites of similar redox state. The inclusions define a primitive suite with properties indicating 8 as F3 and one of even lower petrologic type. The abundant minerals include: low-Ca pyroxene, olivine, plagioclase, kamacite, taenite, schreibersite, troilite, ferroan alabandite and daubreelite. Diopside, oldhamite and a Ti-rich sulfide are present in one or two inclusions. Petrologic textures and jadeitic pyroxene, hitherto unidentified in meteorites, indicate substantial degree of shock. The inclusions acquired their chemical characteristics during nebular condensation and accretion over a broad redox range (metal-silicate trends in them verify Prior's Rules): their parent body later impacted the enstatite meteorite parent body. During impact, the inclusions were shocked and incorporated with enstatite achondrite host as a breccia that would become Cumberland Falls. 相似文献
948.
Goethite contained in lateritic bauxites or in artificial mineral admixtures is completely transformed into peculiar Fe-alkoxide compounds by reaction with glycerol at 245°C. Magnetic spinel oxides result from hydrolysis by boiling water of alkoxides obtained from the artificial admixtures. On the other hand, the production of magnetic spinel materials is not observed in alkoxides derived from natural lateritic samples. This may be caused by the high amount of Al substituting for Fe in these Venezuelan lateritic goethites. 相似文献
949.
S. Siegesmund H. Jelsma J. Becker G. Davies P. Layer E. van Dijk L. Kater M. Vinyu 《International Journal of Earth Sciences》2002,91(1):20-34
In order to constrain the temporal relationship between granite (sensu lato) emplacement and metamorphism, isotope work was carried out on the minerals zircon and apatite (U-Pb), garnet (Pb-Pb) and hornblende (Ar-Ar) from wall rock samples in the Shamva area in Zimbabwe. The area, encompassing parts of the Chinamora and Murehwa batholiths and a wedge-shaped greenstone belt segment in between, is commonly quoted in the literature as an example illustrating pluton emplacement processes and deformational models for the Archean. New U-Pb dating of apatite from a boudinaged pegmatite within mafic schists in the batholith-greenstone contact zone has yielded an age of 2619 +28/-24 Ma. This age is interpreted as the best estimation of the intrusion age of this unit, depending on the assumed closure temperature, and provides an upper age limit for the syntectonic emplacement of the now gneissic granites. Pb-Pb dating of late kinematic garnets in cordierite-bearing rocks within the greenstone belt wall rocks gives an age of 2623NJ Ma. Together, this timing of relatively late, syntectonic plutonism and metamorphic mineral growth at ca. 2.62 Ga compares well with existing zircon crystallization ages for felsic volcanics (2645dž Ma, 2643NJ Ma) and post-tectonic porphyritic monzogranites (2601ᆢ Ma). Ar-Ar hornblende ages for mafic schists from different areas within the greenstone belt wall rocks range between 2621 and 2498 Ma and have been interpreted to indicate mixing between metamorphic ages and cooling ages. The data support a geological model whereby volcanism and sedimentation are associated with an early phase of regional deformation at ca. 2.64 Ga, which may have started earlier and lasted longer, and evolves into the voluminous emplacement of granites (now gneissic granites) in the batholiths at approximately 2.62 Ga. Emplacement of post-tectonic tabular monzogranites takes place at ca. 2.60 Ga. 相似文献
950.
G. Samudro B. Eng. M. Eng. S. Mangkoedihardjo B. Eng. M.Sc. E.S. Ph.D. 《International Journal of Environmental Science and Technology》2006,3(3):261-267
This paper proposed a simple method and rapid to carry out for organizing city phytostructure. Carbon dioxide sequestration was addressed and referred to population number instead of city area. The unit storage of carbon dioxide, which was nothing less than greenspace area, was determined using equivalent method of determining unit storage of water. For various population number (P) of city area in Indonesia, the greenspace unit (GU) was 29P?0.3 ? 3.2, and the greenspace area (GA) was 29P07–3.2P. Greenspace distribution was preferably on wetlands, river lines, top ground level, and north south direction. 相似文献