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排序方式: 共有432条查询结果,搜索用时 0 毫秒
71.
72.
A 34 year-old woman, working with pine wood treated with sodium hydroxide and pyrogallol, developed dermatitis on arms, face and neck. Patch testing showed allergic reaction to colophony and pine wood, but not to sodium hydroxide or pyrogallol. Pine wood contains colophony. Since avoiding pine wood, she has had no further attack of dermatitis. 相似文献
73.
Yi‐Jun Xu Gisela Weinberg Xi Liu Olaf Timpe Robert Schlögl Dang Sheng Su 《Advanced functional materials》2008,18(22):3613-3619
Nanoarchitecturing of carbon nanospheres onto the surface of activated carbon (AC) gives birth to a new composite carbon material that features a hierarchical structure with macro‐ and nanometer dimensions of the respective carbon components and exhibits a remarkably enhanced adsorption capability for heavy‐metal ions ( and Fe3+) from aqueous solution as compared to AC. Thus, we first propose that nanoarchitecturing of AC can be utilized not only as a flexible method for the synthesis of novel, hybrid, nanostructured composite carbon materials but also as a new and “green‐route” strategy for functionalization of the surface of AC in an effective manner. Hence, there is scope for a possible new concept in the functionalization of industrial AC for specific applications. 相似文献
74.
Felix Kexel Alexandra von Kameke Janina Tenhaus Marko Hoffmann Michael Schlüter 《化学,工程师,技术》2021,93(5):830-837
A consecutive competitive gas-liquid reaction is investigated using a Taylor bubble setup regarding the influence of fluid mixing in the bubble wake on yield and selectivity. The concentration fields behind a Taylor bubble are visualized and measured quantitatively with a novel time-resolved absorption imaging technique based on Beer Lamberts law and an integral selectivity is derived. In addition, the calculation of the local selectivity, often used in numerical approaches, is discussed and the existing experimental limits for its derivation are pointed out. Finally, an increase in selectivity of a competitive consecutive reaction for enhanced mixing is experimentally confirmed. 相似文献
75.
The time-dependent operation of methanol, ammonia, and urea production units embedded in a steel mill environment is analyzed with dynamic simulation models. From different process concepts and gas availability scenarios, a set of simulation cases is defined with blast furnace gas as carbon and coke oven gas as hydrogen source. Dynamic simulations indicate that significant CO2 reductions require large amounts of additional H2 from sustainable sources. From the results, global data such as carbon footprint or energy demands and details about process unit operation are obtained and processed. 相似文献
76.
E Schl?ricke H Schmidt HA Schulze R Beck R Guthoff U Falkenhagen 《Canadian Metallurgical Quarterly》1997,94(11):785-790
BACKGROUND: A major goal in research on intraocular lenses (IOL) is the development of new polymers and modifications to reduce foreign-body reactions after implantation. This effect may be achieved by a reduction in the surface hydrophobicity of the polymers. To illustrate the influence of surface modifications on bacterial adhesiveness, the most often isolated organism in "low-grade" postoperative endophthalmitis, Staphylococcus epidermidis, was used. MATERIALS AND METHODS: For this reason three strains of this species, the type strain ATCC 14990 and two clinical isolates (8687, 6579 I) with different hydrophobic surface properties were studied. IOL, used in the experiments were either made of PMMA or silicone with modified surfaces (unpolished, polished, heparinized). The adhesiveness of H3-thymidin-labeled bacteria was calculated/mm2 of lens surface. Each experiment was performed in triplicate and repeated three times. RESULTS: The hydrophobic-type strain showed stronger adherence to unpolished PMMA surface (8000 bacteria per mm2) compared to the polished (5200 bacteria/mm2). In contrast, the hydrophilic strain adhered with 2000 bacteria/mm2 to the unpolished and with 4200 bacteria/mm2 to the polished surface. Polishing PMMA lenses diminished the differences between the three strains. However, surface passivation of silicone lenses increased the adhesion rate of the hydrophilic strain up to 9600 bacteria/mm2. Treatment of PMMA lenses with heparin increased the adhesiveness of the hydrophilic strain and reduced the adhesion rate of the hydrophobic type strain to 250 bacteria/mm2. CONCLUSIONS: It was demonstrated that bacterial adherence to IOL also involves hydrophobic interactions. Obviously, however, that adherence reflects a complex of interactions between the two surfaces. 相似文献
77.
E.-U Schlünder N Mollekopf 《Chemical Engineering and Processing: Process Intensification》1984,18(2):93-111
The drying rate of packed and mechanically agitated beds heated by immersed surfaces is controlled by the contact heat transfer resistance at the surface followed by the heat penetration resistance of the wet bulk. Both resistances can be predicted from model equations with sufficient accuracy. The contact resistance and the bulk penetration resistance for packed beds follow from physical properties, while the prediction of the bulk penetration resistance for mechanically agitated beds requires the introduction of an empirical parameter, the so-called mixing number, in order to describe the random particle motion. The mixing number was found to lie between 2 and 25, depending on the dryer type as well as on the Froude number. It is identical for dry and for wet beds. 相似文献
78.
79.
Study of on-line adaptive discriminant analysis for EEG-based brain computer interfaces 总被引:3,自引:0,他引:3
Vidaurre C Schlögl A Cabeza R Scherer R Pfurtscheller G 《IEEE transactions on bio-medical engineering》2007,54(3):550-556
A study of different on-line adaptive classifiers, using various feature types is presented. Motor imagery brain computer interface (BCI) experiments were carried out with 18 naive able-bodied subjects. Experiments were done with three two-class, cue-based, electroencephalogram (EEG)-based systems. Two continuously adaptive classifiers were tested: adaptive quadratic and linear discriminant analysis. Three feature types were analyzed, adaptive autoregressive parameters, logarithmic band power estimates and the concatenation of both. Results show that all systems are stable and that the concatenation of features with continuously adaptive linear discriminant analysis classifier is the best choice of all. Also, a comparison of the latter with a discontinuously updated linear discriminant analysis, carried out in on-line experiments with six subjects, showed that on-line adaptation performed significantly better than a discontinuous update. Finally a static subject-specific baseline was also provided and used to compare performance measurements of both types of adaptation. 相似文献
80.
Hyperspectral imaging (HSI) sensors suffer from spatial misregistration, an artifact that prevents the accurate acquisition of the spectra. Physical considerations let us assume that the influence of the spatial misregistration on the acquired data depends both on the wavelength and on the across-track position. A scene-based method, based on edge detection, is therefore proposed. Such a procedure measures the variation on the spatial location of an edge between its various monochromatic projections, giving an estimation for spatial misregistration, and also allowing identification of misalignments. The method has been applied to several hyperspectral sensors, either prism, or grating-based designs. The results confirm the dependence assumptions on lambda and theta, spectral wavelength and across-track pixel, respectively. Suggestions are also given to correct for spatial misregistration. 相似文献