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171.
S. Jung K. Mezger O. Nebel E. Kooijman J. Berndt F. Hauff C. Münker 《Contributions to Mineralogy and Petrology》2012,163(1):1-17
Leucocratic granites of the Proterozoic Kaoko Belt, northern Namibia, now preserved as meta-granites, define a rock suite
that is distinct from the surrounding granitoids based on their chemical and isotopic characteristics. Least evolved members
of this ~1.5–1.6-Ga-old leucogranite suite can be distinguished from ordinary calc-alkaline granites that occur elsewhere
in the Kaoko Belt by higher abundances of Zr, Y, and REE, more radiogenic initial εNd values and unradiogenic initial 87Sr/86Sr. The leucogranites have high calculated zircon saturation temperatures (mostly > 920°C for least fractionated samples),
suggesting that they represent high-temperature melts originating from deep crustal levels. Isotope data (i.e., εNdi: +2.3 to –4.2) demonstrate that the granites formed from different sources and differentiated by a variety of processes including
partial melting of mantle-derived meta-igneous rocks followed by crystal fractionation and interaction with older crustal
material. Most fractionation-corrected Nd model ages (TDM) are between 1.7 and 1.8 Ga and only slightly older than the inferred intrusion age of ca. 1.6 Ga, indicating that the precursor
rocks must have been dominated by juvenile material. Epsilon Hf values of zircon separated from two granite samples are positive
(+11 and +13), and Hf model ages (1.5 and 1.6 Ga) are similar to the U–Pb zircon ages, again supporting the dominance of juvenile
material. In contrast, the Hf model ages of the respective whole rock samples are 2.3 and 2.4 Ga, demonstrating the involvement
of older material in the generation of the granites. The last major tectonothermal event in the Kaoko Belt in the Proterozoic
occurred at ca. 2.0 Ga and led to reworking of mostly 2.6-Ga-old rocks. However, the presence of 1.6 Ga “post-collisional”
granites reflects addition of some juvenile mantle-derived material after the last major tectonic event. The results suggest
that similar A-type leucogranites are potentially more abundant in crustal terranes but are masked by AFC processes. In the
case of the Kaoko Belt, it is suggested that this rock suite indicates a yet unidentified period of mantle-derived crustal
growth in the Proterozoic of South Western Africa. 相似文献
172.
Jiyeol Im Jinyoung Jung Hyokwan Bae Daeik Kim Kyungik Gil 《Environmental Earth Sciences》2014,72(1):289-297
Nitritation is an innovative biological nitrogen removal method in wastewater, and it has the advantages of energy and economy. The correlation between a nitrite conversion rate and the gene copy numbers of ammonia oxidizing bacteria (AOB) in a nitritation reactor was examined to measure the effectiveness of removing a nitrogen content in a biological nitrogen removal process, using a biological process of nitritation. A laboratory scale reactor was prepared and operated for over a year, using digester supernatant to induce a stable nitritation, and to optimize the operational conditions by adjusting various operating factors. The relationship between operational results of nitritation reactor and the AOB gene copies was approximated through identification and quantitative analysis of AOB. A stable nitritation can be artificially led with the control of SRT, while treating anaerobic digester supernatant from MWTPs. And AOB gene copies showed a correlation with free ammonia (FA) inhibition and performance of nitritation, and AOB activity. Thus, AOB gene copies were found important when it comes to analyzing nitritation. 相似文献
173.
Performance-based design demands accurate prediction of soil deformation under a working load condition. The nonlinear stress–strain behavior needs to be analyzed quantitatively to advance the understanding of complex soil behavior in the pre-failure condition. The singular value decomposition technique is introduced to quantitatively analyze the compliance matrix representing the strain response envelope (SRE). The rotation of the ellipse of the SRE relates to the anisotropic response of the soil deformation. The off-centered SRE provides evidence of the kinematic hardening plasticity. Quantitative data on the movement of SREs provide us with crucial information to investigate the effect of stress history and the evolution of stiffness anisotropy in soil deformation. 相似文献
174.
Cholinesterases (ChEs) have been characterized in marbled sole (Limanda yokohamae) for use as a possible biomarker of pollution exposure. In brain, ChEs existed almost exclusively (>95%) as acetylcholinesterase (AChE) whereas in muscle, about 20-30% of ChE activity was in the form of butyrylcholinesterase (BChE; pseudocholinesterase). Acetylthiocholine and butyrylthiocholine (identified in mammalian studies as diagnostic substrates for AChE and BChE respectively) were hydrolyzed mainly, but not exclusively, by these enzymes. The inhibitors BW284C51 and iso-OMPA (identified in mammalian studies as diagnostic inhibitors of AChE and BChE respectively) were not specific for these enzymes in marbled sole. Brain AChE and muscle AChE and BChE were characterized in terms of their kinetic properties (KM etc.) and optimal conditions (substrate concentration, protein concentration, pH etc.) were established to allow routine assays of ChE activity to proceed under pseudo-first order conditions. The sensitivity of ChEs to a locally significant pesticide, iprobenfos (IBP; kitazin) was established in terms of IC50 concentrations. Brain AChE was relatively insensitive to IBP, but muscle AChE and BChE were sensitive to IBP concentrations in the high nM range. However, ambient IBP concentrations in Korean coastal waters are usually not high enough to cause detectable ChE inhibition in this species. 相似文献
175.
Ocean Science Journal - Age and growth estimations are important fisheries management tools to gain insight into the population structures of commercially important fish species. Despite their... 相似文献
176.
The interaction of geomechanics and flow within a soil body induces deformation and pore pressure change. Deformation may change hydrogeological and elastic properties, which alters the mechanical behaviour and results in non‐linearity. To investigate this interaction effect in a heterogeneous porous medium, a stochastic poroelastic model is proposed. Monte Carlo simulations are performed to determine the mean and uncertainty of the parameter changes, displacement, and change in pore water pressure. Hydraulic conductivity is treated as the only random variable in the coupled geomechanics‐flow system due to its large variation compared to other mechanical and hydrogeological properties in natural environments. The three considered non‐linear models for the interaction between parameters and deformation are those that consider (1) porosity and hydraulic conductivity; (2) porosity and Young's modulus; and (3) a combined effect that includes porosity, hydraulic conductivity, and Young's modulus. Boundary effects on the coupled system are also explored. The relationships between changes of porosity, hydraulic conductivity, and Young's modulus are analytically shown to be non‐linear. Among the considered parameters, the deformation effect induces the largest reduction in hydraulic conductivity. The deformation‐induced change in hydraulic conductivity shows the most significant effect on the mean and variance of the change in pore water pressure and displacement, while changes in Young's modulus have the least effect. When the deformation effect is considered, the superposition relationship does not exist in the mean displacement and mean change in pore water pressure for the three scenarios considered; it exists for the case without deformation effects. Deformation also causes a reduction in the effective hydraulic conductivity for the whole domain. The scenario that considers both loading and discharge boundaries has larger changes in hydrogeological and geo‐mechanical parameters than those in scenarios that consider loading and discharge boundaries separately. The results indicate that the interaction between deformation and changes in parameters has a profound effect on the poroelastic system. The effect of deformation should thus be considered in modelling and practice. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
177.
Jung Hae Choi A. H. M. Faisal Anwar Katsuyuki Kawamura Yasuaki Ichikawa 《国际地质力学数值与分析法杂志》2009,33(5):687-707
Kaolinite is a common clay mineral. It is a nanomaterial with a platelet crystalline structure. In order to analyze the behavior of kaolinite, its microscopic structure and material properties must be specified correctly. A molecular dynamics (MD) simulation is used for determining the microscale properties of hydrated kaolinite, and these properties are introduced into a multiscale homogenization analysis (HA). We previously developed such an MD/HA technique to investigate seepage, diffusion, sorption and consolidation in bentonite clay (Proceedings of the Science Basis for Nuclear Waste Management, Davos, Switzerland, vol. XXI. Material Research Society: Warrendale, PA, 1997; 359–366; Eng. Geol. 1999; 54 :21–31; Eng. Geol. 2001; 60 :127–138; Coupled Thermo‐Hydro‐Mechanical‐Chemical Processes in Geo‐systems. Elsevier: Amsterdam, 2005; 457–464). We here apply the method to kaolinite clay to investigate the permeability, diffusion and related similitude law. The obtained results are supported by existing experimental data. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
178.
Jeonghoon Lee Byeongju Jung Jun-Mo Kim Kyung-Seok Ko Ho-Wan Chang 《Environmental Earth Sciences》2011,63(4):763-770
Understanding groundwater flow and chemical transport is crucial for operating underground storage caverns. Groundwater flow
in the study area is mainly affected by cavern operating conditions, and groundwater chemistry in the study area is modified
by disinfection activities for removing possible biological clogging and by mixing with cement pore water. It is significant
to discern these two effects because wells affected by the disinfection activities, in particular, may have hydrological connections
with water curtains in which disinfectant water was injected to remove the biological clogging. Concentration of tritium (3H) and helium isotopes (4He), and groundwater chemical compositions were used to confirm that there are hydrological connectivities between the water
curtain and the well. Groundwater along the fault areas contains low total dissolved solid (TDS) and high 3H, suggesting that the faults may act as fast flow conduits, which is not inconsistent with previous studies. Certain diagnostic
conditions (high concentrations of Na+, Cl− and TDS and high pH) are presumed by the effect of disinfection activity, indicating that there are hydrological connections
between the water curtain and the wells. This hypothesis is valid in YK2U and YK2L, but is not in YK12L, implying a closed
system or an immobile water to explain the isotopic results. 相似文献
179.
Surface sediment from the coastal bays of Gwangyang and Masan in South Korea were analyzed for their contents and isotopic
values of organic carbon and total nitrogen. The sources and diagenetic alteration of organic matter were also assessed. Total
organic carbon varied from 0.22% to 3.48% (average = 1.40%, n = 75), and C/N ratios varied from 2.4 to 15.2 (average = 8.79,
n = 75). δ13Corg ranged from −19.92‰ to −25.86‰ (average = −21.21‰, n = 75), and δ15NTN ranged from 8.57‰ to 3.93‰ (average = 6.49‰, n = 75). Total organic carbon in both areas was associated with grain-size,
with higher contents in finer grained sediment. The high carbon content observed in Masan Bay sediment correlated with its
higher C/N ratio. δ13Corg and δ15NTN varied widely, attributable to various influences such as the input of terrestrial organic matter and diagenetic alteration.
The depleted δ13Corg and higher δ15NTN observed in the sediment of Gwangyang Bay reflected terrestrial supply, implying that biogeochemical processes, i.e. bacterial
degradation, were more active in Masan Bay sediment, which showed less depleted δ13Corg and higher δ15NTN than Gwangyang Bay sediment. δ15NTN was the more useful indicator of biogeochemical processes in the highly anoxic sediment. These results indicate that the
δ13Corg and δ15NTN of sedimentary organic matter in coastal bays can indicate the source and degree of diagenetic alteration of sedimentary
organic matter. 相似文献
180.
Haingja Seo Sungwon Hwang Aeran Jung Ji Hyun Kim Joo Hyeon Kim Kap-Sung Kim Jinny Lee Minhwan Jang 《Icarus》2007,192(1):287-295
We have constructed synthetic solar spectra for the 2302-4800 cm−1 (2.08-4.34 μm) range, a spectral range where planetary objects mainly emit reflected sunlight, using ATMOS (Atmospheric Trace Molecule Spectroscopy)/Spacelab-3 and Atlas-3 spectra, of which resolution is 0.01 cm−1. We adopted Voigt line profiles for the modeling of line shapes based on an atlas of line identifications compiled by Geller [Geller, M., 1992. Key to Identification of Solar Features. A High-Resolution Atlas of the Infrared Spectrum of the Sun and the Earth Atmosphere from Space. NASA Reference Publ. 1224, vol. III. NASA, Washington, DC, pp. 1-22], who derived solar line positions and intensities from contaminated high-resolution solar spectra obtained by ATMOS/Spacelab-3. Because the ATMOS spectra in these wavelength ranges are compromised by absorption lines of molecules existing in Earth's high-altitude atmosphere and in the compartment of the spacecraft, the direct use of these high-resolution solar spectra has been inconvenient for the data reductions of planetary spectra. We compared the synthetic solar spectra with the ATMOS spectra, and obtained satisfactory fits for the majority of the solar lines with the exception of abnormal lines, which do not fit with Voigt line profiles. From the model fits, we were able to determine Voigt line parameters for the majority of solar lines; and we made a list of the abnormal lines. We also constructed telluric-line-free solar spectra by manually eliminating telluric lines from the ATMOS spectra and filling the gaps with adjacent continua. These synthetic solar spectra will be useful to eliminate solar continua from spectra of planetary objects to extract their own intrinsic spectral features. 相似文献