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41.
42.
The transformation of chemically bound gold into metallic gold during industrial scale roasting of an arsenical gold ore concentrate from the Fairview Mine, Eastern Transvaal, has been studied quantitatively by197Au Mössbauer spectroscopy. The iron compounds in the concentrate, mainly FeAsS and FeS2 and their transformations during roasting have been studied by57Fe Mössbauer spectroscopy. The bound gold is found to convert into the metal in parallel to the decomposition of FeAsS and the increase in cyanide leachability. this shows that the refractory character of the ore is caused by the chemical bonding of the gold rather than by the physical inclusion of small, discrete metallic particles in the matrix of FeAsS or FeS2. The ratio of thef-factors of gold bound in the FeAsS component of a refractory ore and of metallic gold was determined to bef(Au:FeAsS)/f(Au)=1.48±0.09. 相似文献
43.
The purpose of this paper is to present part of a computer aided design model which was developed for the analysis of millimeter wave rectangular waveguide circuits. This paper focuses on cap resonator circuits and pre-tuned modules for Gunn andimpatt oscillators in the W band. The theoretical results were verified through comparisons with experiments performed in the Ku band. The influence of the main cap circuit parameters are analyzed in order to provide a guidance for theptm design. 相似文献
44.
Small crystals of the title compound are grown from BaAl2O4, Y2BaO4, and MnO in a floating‐zone mirror‐image furnace. 相似文献
45.
Hans J. Breunig Prof. Dr. Enno Lork Ovidiu Moldovan Ciprian I. Raţ 《无机化学与普通化学杂志》2010,636(6):1090-1094
The iron complexes [(Et2Sb)4Fe4(CO)14] ( 1 ), [(nPr2Sb)4Fe3(CO)10] ( 2 ), [{(Me3SiCH2)2Sb}4Fe2(CO)6] ( 3 ), and [2‐(Me2NCH2)C6H4SbFe2(CO)8] ( 4 ) were prepared by reactions of distibanes with Fe2(CO)9. Compounds 1 – 4 were characterized by X‐ray diffraction, 1H NMR and IR spectroscopy as well as mass spectrometry; complex 1 was additionally characterized by density functional calculations. 相似文献
46.
47.
Frédérick Adam Didier Thiébaut Fabrice Bertoncini Marion Courtiade Marie-Claire Hennion 《Journal of chromatography. A》2010,1217(8):1386-1394
This paper reports the conditions of online hyphenation of supercritical fluid chromatography (SFC) with twin comprehensive two-dimensional gas chromatography (twin-GC × GC) for detailed characterization of middle distillates; this is essential for a better understanding of reactions involved in refining processes. In this configuration, saturated and unsaturated compounds that have been fractionated by SFC are transferred on two different GC × GC columns sets (twin-GC × GC) placed in the same GC oven. Cryogenic focusing is used for transfer of fractions into the first dimension columns before simultaneous GC × GC analysis of both saturated and unsaturated fractions. The benefits of SFC–twin-GC × GC are demonstrated for the extended alkane, iso-alkane, alkene, naphthenes and aromatics analysis (so-called PIONA analysis) of diesel samples which can be achieved in one single injection. For that purpose, saturated and unsaturated compounds have been separated by SFC using a silver loaded silica column prior to GC × GC analysis. Alkenes and naphthenes are quantitatively recovered in the unsaturated and saturated fractions, respectively, allowing their identification in various diesel samples. Thus, resolution between each class of compounds is significantly improved compared to a single GC × GC run, and for the first time, an extended PIONA analysis of diesel samples is presented. 相似文献
48.
Andrea Retzbach Joachim Marschall Marion Rahnke Lukas Otto Michaela Maier 《Journal of nanoparticle research》2011,13(12):6231-6244
In this article, we report data from an online questionnaire study with 587 respondents, representative for the adult U.S.
population in terms of age, gender, and level of education. The aim of this study was to assess how interest in science and
knowledge as well as beliefs about science are associated with risk and benefit perceptions of nanotechnology. The findings
suggest that the U.S. public is still rather unfamiliar with nanotechnology. Those who have some knowledge mainly have gotten
it from TV and the Internet. The content of current media reports is perceived as fairly positive. Knowledge of scientific
methods is unrelated to benefit and risk perceptions, at least when other predictors are controlled. In contrast, positive
beliefs about science (e.g., its impact on economy or health) and more sophisticated epistemological beliefs about the nature
of scientific knowledge are moderately linked to more positive perceptions of nanotechnology. The only exception is the perception
of scientific uncertainty: This is associated with less positive evaluations. Finally, higher engagement with science is associated
with higher risk perceptions. These findings show that laypersons who are engaged with science and who are aware of the inherent
uncertainty of scientific evidence might perceive nanotechnology in a somewhat more differentiated way, contrary to how it
is portrayed in the media today. 相似文献
49.
50.
Characterization and functionalization of cellulose microbeads for extracorporeal blood purification
Marion Ettenauer Fritz Loth Katrin Thümmler Steffen Fischer Viktoria Weber Dieter Falkenhagen 《Cellulose (London, England)》2011,18(5):1257-1263
In the frame of this work, cellulose microbeads with an average particle size of 2.3 μm were characterized with respect to
porosity using a batch solute exclusion method and two groups of model substances, namely proteins and polystyrene sulfonates.
The pores of the microbeads were almost completely accessible to proteins with Stokes radii below 2.5 nm. More than 60% of
the pores were accessible to albumin, which is relevant for the application in blood purification, since many target substances
are albumin bound. Activation of the microbeads with increasing amounts of sodium metaperiodate yielded matrices with dialdehyde
contents between 100 and 1,000 μmol/g. The activated beads were well suited for the covalent attachment of functional ligands,
such as antibodies. Immobilization of antibodies against the pro-inflammatory cytokine TNF-α resulted in efficient TNF-α adsorbents
which possess application potential in extracorporeal blood purification, e.g. for the modulation of cytokine levels as supportive
therapy for sepsis and other inflammatory disorders. 相似文献