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Theoretical and Applied Climatology - Air temperature inversions are common features in Antarctica, especially in the interior where they are observed nearly year-round. Large temporal variability...  相似文献   
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Continuous, very long baseline interferometry (VLBI) campaigns over 2 weeks have been carried out repeatedly, i.e., CONT02 in October 2002, CONT05 in September 2005, CONT08 in August 2008, and CONT11 in September 2011, to demonstrate the highest accuracy the current VLBI was capable at that time. In this study, we have compared zenith total delays (ZTD) and troposphere gradients as consistently estimated from the observations of VLBI, Global Navigation Satellite Systems (GNSS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) at VLBI sites participating in the CONT campaigns. We analyzed the CONT campaigns using the state-of-the-art software following common processing strategies as closely as possible. In parallel, ZTD and gradients were derived from numerical weather models, i.e., from the global European Centre for Medium-Range Weather Forecasts (ECMWF) analysis fields, the High Resolution Limited Area Model (European sites), the Japan Meteorological Agency-Operational Meso-Analysis Field (MANAL, over Japan), and the Cloud Resolving Storm Simulator (Tsukuba, Japan). Finally, zenith wet delays were estimated from the observations of water vapor radiometers (WVR) at sites where the WVR observables are available during the CONT sessions. The best ZTD agreement, interpreted as the smallest standard deviation, was found between GNSS and VLBI techniques to be about 5–6 mm at most of the co-located sites and CONT campaigns. We did not detect any significant improvement in the ZTD agreement between various techniques over time, except for DORIS and MANAL. On the other hand, the agreement and thus the accuracy of the troposphere parameters mainly depend on the amount of humidity in the atmosphere.  相似文献   
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Two types of compositionally heterogeneous slags have been found in the wall masonry of the Gothic Castle ruin Obřany. The bright phase is composed of quartz, tridymite, cristobalite, and porous glass, while the dark one also contains feldspars, hercynite, magnetite, clinopyroxenes, and a suite of accessory phases. The bright slags have a similar chemical composition as the mortar from the castle masonry or local sandstones, based on rare earth elements (REE) and other trace element abundances. In contrast, the dark slags are characterized by elevated contents of Al2O3 (15.4–18.6 wt.%) and Fe2O3tot (4.1–10.0 wt.%), and consequently resemble the local clay. The investigated slags are not related to iron metallurgy in terms of their composition and texture. They probably originated in a medieval lime kiln through heat sintering of the inner lining during the burning process under relatively high temperatures (1080–1500°C). Simultaneously, the finding of relics of clinker‐like material together with products of its hydration in the hydraulic mortar from the wall masonry infers the production of hydraulic lime or Roman cement during the construction of the castle in the 14th century. The Obřany Castle appears to represent one of the first applications of hydraulic binders in Moravia.  相似文献   
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The magnetic map of Slovakia used in the paper was compiled as part of a project titled Atlas of Geophysical maps and profiles in 2001. The residual magnetic data were analyzed to produce Curie point estimates. To remove distortion of magnetic anomalies caused by the Earth’s magnetic field, reduction to pole transformation was applied to the magnetic anomalies using the magnetization angle of the induced magnetization. Anomalies reduced to the pole tend to be better correlated with tectonic structures. We applied a 3-km upward continuation to the residually compiled magnetic anomalies in order to remove effects of topography. The depth of magnetic dipoles was calculated by an azimuthally averaged power spectrum method for the entire area. Such estimates can be indicative of temperatures in the crust, since magnetic minerals lose their spontaneous magnetization according to Curie temperature of the dominant magnetic minerals in the rocks. The computed Curie point depths in the Slovakia region vary between 15.2 km and 20.9 km. Heat flow higher than 100 mWm−2 occurs at the central volcanics and eastern part of Slovakia, where the Curie point depths values are shallow. The correlation between Curie point depths, heat flow and crust depth was investigated for two E-W cross sections. Heat flow and Curie point depth values are correlated with each other however, these values could not be correlated with crust depth. The Curie point isotherm, which separates magnetic and non-magnetic parts of the crust, is represented in two cross sections.  相似文献   
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Open‐cast mining activity causes the largest georelief transfigurations all over the world. Large localities in north‐west Bohemia (the Czech Republic) are affected. In this area, we focus on a very significant case: the royal town Most, which has been turned into a lake. The main aim of this article is the reconstruction of the original georelief in different time periods together with analysis showing the process of landscape devastation. The workflow and analysis is based on precise elevation data obtained from aerial photographs and old maps. The georelief development is reconstructed using the digitized contour lines contained in Derived state‐map 1:5,000 (SMO5) from the years 1953, 1972, and 1980; maps of the 3rd Military Survey (year 1936); and digital surface models (DSM) extracted, using the pixel correlation method, from aerial images (year 1953 and 2008). The most important results of the analysis are digital terrain models showing the evolution of the landscape which may be used for many purposes in landscape development analysis, historical applications, visualization or landscape reclamation.  相似文献   
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In this study, the oxidative decolorization of C.I. reactive yellow 145 (RY 145) from synthetic textile wastewater including RY 145 and polyvinyl alcohol by Fenton and sono‐Fenton processes which are the combination of Fenton process with ultrasound has been carried out. The effects of some operating parameters which are the initial pH of the solution, the initial concentration of Fe2+, H2O2, and the dye, temperature, and agitation speed on the color and chemical oxygen demand (COD) removals have been investigated. The optimum conditions have been found as [Fe2+] = 20 mg/L, [H2O2] = 20 mg/L, pH 3 for Fenton process and [Fe2+] = 20 mg/L, [H2O2] = 15 mg/L, pH 3 for sono‐Fenton process by indirectly sonication at 35 kHz ultrasonic frequency and 80 W ultrasonic power. The color and COD removal efficiencies have been obtained as 91 and 47% by Fenton process, and 95 and 51% by sono‐Fenton processes, respectively. Kinetic studies have been performed for the decolorization of RY 145 under optimum conditions at room temperature. It has been determined that the decolorization has occurred rapidly by sono‐Fenton process, compared to Fenton process.  相似文献   
29.
The thermodynamical stability of a newly observed wadsleyite II phase in the Mg2SiO4 system is studied by the density functional theory. The wadsleyite II equation of state has been derived. The phase boundaries of Mg2SiO4 polymorphs: wadsleyite, wadsleyite II and ringwoodite are studied using the quasi-harmonic approximation at high external pressures. Clapeyron slopes determined for wadsleyite II–ringwoodite and wadsleyite–wadsleyite II boundaries are 0.0047 and 0.0058 GPa/K, respectively. It is shown that the wadsleyite II phase is not thermodynamically preferred in the pure Mg2SiO4 system and will probably not occur between wadsleyite and ringwoodite phases.  相似文献   
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The unconfined compression test (UCT) is one of the most common tools to measure the undrained shear strength of fine-grained soils. Soft to very soft soils often pose problems such that the determination of failure load is unclear using this test. Similarly, fissured clays would endeavor failure along pre-existing planes of weakness. The reverse extrusion test (RET), a mechanical metallurgy tool, has been used recently in some soil mechanics applications. The scope of this investigation is to evaluate the potential of the RET as a substitute for the UCT. Sixty remolded soils and 75 natural soils were subjected to the RET and UCT. Remolded soils were tested on mixtures prepared at the plastic limit. It was found that the ratio of extrusion pressure at failure to the undrained shear strength is relatively consistent and concentrates around 14. The same ratio was found to be 15 for natural soils. The conclusion reached, upon a series of tests on both the remolded and natural soil samples, is that the RET better represents the undrained shear strength of soil than does the UCT, that the practical difficulties with UCT is eliminated by the RET, and the results may be improved by taking into account soil plasticity.  相似文献   
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