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231.
The equilibrium oxygen pressure over the Cr-Y2O3-YCrO3 coexistence has been measured by the following cells: Cr, Y2O3, YCrO3∥ZrO2∥Cr, Cr2O3 [I] Mn, MnO∥ZrO2∥Cr, Y2O3, YCrO3 [II] Moreover, the partial electronic conduction parameter,P e, has been determined simultaneously, as the oxygen partial pressure where then-type electronic and ionic conductivities are equal in the stabilized ZrO2. The equilibrium oxygen pressure,P O 2, over the Cr-Y2O3-YCrO3 coexistence andP e are expressed as log (PO 2/atm) = 10.6 − 4.39 × 1041/T ± 0.1 (1385 to 1470 K) log ( Pe/atm = 8.86 − 4.21 x 104 1/T ± 0.3 (1385 to 1470 K) From the equilibrium oxygen pressure and the standard Gibbs energy of formation of Y2O3, the standard Gibbs energy of formation of YCrO3 is calculated as ΔG o f /J mol™1 = −1.58 x 106 + 2.93 x 102 T ± 7 × 103 (1385 to 1470 K)  相似文献   
232.
Shock compaction of silicon carbide powder   总被引:1,自引:0,他引:1  
A series of shock compaction experiments on SiC powder were carried out over a wide range of shock pressures and shock temperatures up to 30 GPa and 3400 K. Large changes in some physical properties and a variety of unique microstructures were observed in the shock-treated samples with changes in impact conditions. For an iron plate impactor, the optimum impact condition, which depends on the initial density, is 2.5 km sec–1 for 70% initial density and 2.0 km sec–1 for 50%. The best-sintered compact of SiC with 97% density and micro-Vicker's hardness of 2700 kg mm–2 was obtained under optimum conditions. Good compacts with high relative density and high strength exhibit the disruptive effects of the shock wave, which are indicated by microstrain increase and crystallite size reduction. The skin model is presented here in order to estimate the heterogeneous shock state which is realized under and after shock loading of the initial powder aggregates.  相似文献   
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234.
We have developed a parallel and distributed computing framework to solve an inverse problem, which involves massive data sets and is of great importance to petroleum industry. A Monte Carlo method, combined with proxies to avoid excessive data processing, is employed to identify reservoir simulation models that best match the oilfield production history. Subsequently, the selected models are used to forecast future productions with uncertainty estimates. The parallelization framework combines: (1) message passing for tightly coupled intra-simulation decomposition; and (2) scheduler/Grid remote procedure calls for model parameter sweeps. A preliminary numerical test has included 3,159 simulations on a 256-processor Intel Xeon cluster at the USC-CACS. The results provide uncertainty estimates of unprecedented precision.  相似文献   
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236.
Many chemicals that are not structurally related to estrogen have estrogen-like activity. In this study, we tried to apply a quail embryo culture system for assessing the in vivo effects of such chemicals on the development of quail embryos. Beta-estradiol induced feminization of the gonads of genetically male embryos, which was confirmed by the increase in the size of the left gonad and female-specific aromatase expression, while male-specific SOX9 expression was not affected. Nonylphenol, which has a weak estrogenic activity, reduced the viability and body weight of embryos. Simultaneously, several genetically male embryos were feminized in terms of gonadal size and aromatase expression. These results indicate that the avian embryo culture system was useful for evaluating endocrine disrupters.  相似文献   
237.
In an effort to improve the performance of lead-free solder, Sn-3.5?wt.%Ag (Sn-3.5Ag) solder alloy with 0.03?wt.% carbon black was prepared under high pressure (5.5?GPa) and high temperature (1200°C). We have investigated the microstructure, melting behavior, and mechanical properties of the alloy using x-ray diffraction, differential scanning calorimetry (DSC), Vickers hardness testing, tensile testing, and scanning electron microscopy (SEM). The melting point was found to be unchanged, while the hardness and the tensile strength increased with the addition of carbon black. SEM images showed that the average thickness of the intermetallic compound (IMC) layer decreased with the addition of carbon black, indicating improvement in solder joint reliability.  相似文献   
238.
Oxidation of CO on the FeO x /Pt/TiO2 catalyst is markedly enhanced by H2 and/or H2O at 60 °C, but no such enhancement is observed on the Pt/TiO2 catalyst, but shift reaction (CO + H2O → H2 + CO2) does not occur on the FeO x /Pt/TiO2 catalyst at 60 °C. DRIFT-IR spectroscopy reveals that the fraction of bridge bonded CO increases while that of linearly bonded CO decreases on the FeO x loaded Pt/TiO2 catalyst. The in-situ DRIFT IR spectra proved that the bridged CO is more reactive than the linearly bonded CO with respect to O2, and the reaction of the bridge-bonded CO with O2 as well as of the linearly bonded CO is markedly enhanced by adding H2 to a flow of CO + O2. From these results, we deduced that the promoting effect of H2 and/or H2O is responsible for the preferential oxidation (PROX) reaction of CO on the FeO x /Pt/TiO2 catalyst, and a following new mechanism via the hydroxyl carbonyl or bicarbonate intermediate is proposed for the oxidation of CO in the presence of H2O.   相似文献   
239.
Uridine 5'-hexadecylphosphate (UMPC16) inhibited the growth of Saccharomyces cerevisiae under a hypersaline stress condition with Na+ more strongly than the calcineurin inhibitor cyclosporine A (CsA). Additional Ca2+ supplementation similarly suppressed the inhibitory activities of UMPC16 and CsA on yeast cell growth in a medium with Na+. UMPC16, but not CsA, accelerated mitochondrial reactive oxygen species (ROS) generation in combination with Na+, suggesting its inhibition of a Ca2+ -dependent but calcineurin-independent mechanism for protection against Na+ toxicity.  相似文献   
240.
Adhesion force analysis using atomic force microscopy clearly revealed for the first time the mechanism underlying the specific binding between a titanium surface and ferritin possessing the sequence of Ti-binding peptide in its N-terminal domain. Our results proved that the specific binding is due to double electrostatic bonds between charged residue and surface groups of the substrate. Furthermore, it is also demonstrated that the accretion of surfactant reduces nonspecific interactions, dramatically enhancing the selectivity and specificity of Ti-binding peptide.  相似文献   
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