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排序方式: 共有898条查询结果,搜索用时 62 毫秒
41.
Electrochemical characterization of electrolytes for lithium-ion batteries based on lithium difluoromono(oxalato)borate 总被引:1,自引:0,他引:1
Sandra ZugmannDominik Moosbauer Marius AmerellerChristian Schreiner Franz WudyRené Schmitz Raphael SchmitzPhilipp Isken Christian DippelRomek Müller Miriam KunzeAlexandra Lex-Balducci Martin WinterHeiner Jakob Gores 《Journal of power sources》2011,196(3):1417-1424
The salt lithium difluoromono(oxalato)borate (LiDFOB) showed some promising results for lithium-ion-cells. It was synthesized via a new synthetic route that avoids chloride impurities. Here we report the properties of its solutions (solvent blend ethylene carbonate/diethyl carbonate (3:7, mass ratio), including its conductivity, cationic transference number, hydrolysis, Al-current collector corrosion-protection ability and its cycling performance with some electrode materials. Some Al-corrosion studies were also performed with the help of our recently developed computer controlled impedance scanning electrochemical quartz crystal microbalance (EQCM) that proofed to be a useful tool for battery material investigations. 相似文献
42.
Miriam P. Trubelja Donald Potter Joseph J. Helble 《Journal of Materials Science》2010,45(16):4480-4489
Zirconia particles synthesized under ambient conditions are frequently amorphous, requiring heat to produce a crystalline
phase. Synthesized nanoparticles are generally found in the tetragonal phase. In this article, a room temperature sol–gel
synthesis of crystalline sub-10-nm zirconia particles is described. By adjusting the acid concentration of the reaction, it
is found that the particles’ crystalline phase can be modified. Under acidic conditions with moisture present, the tetragonal
phase is produced, whereas under acidic conditions with low water content, 2–5-nm particles suggestive of the metastable orthorhombic
phase are produced. Subsequent heat treatment of all powders produced with this technique resulted in their transformation
first to the tetragonal phase, and ultimately to the monoclinic phase. The extent of the transformation to the monoclinic
phase depends upon the atmosphere, however, suggesting that oxygen vacancies play a significant role in the stabilization
and determination of the resulting phase. 相似文献
43.
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45.
José L. Lerma Miriam Cabrelles Cristina Portalés 《Construction and Building Materials》2011,25(5):2190-2197
It is well known that the content of water does affect materials behaviour and may cause important damages to buildings, including structural deterioration. Thermography is a non-intrusive imaging technique that allows the inspection of different materials based on their surface temperatures. Within an appropriate thermal analysis, moisture and other structural damages can be detected. The present research work deals with multitemporal thermal analysis to detect moisture on buildings, as well as other alterations. Two different approaches are tested to determine the effectiveness on the moisture surveys, one simple based on image differences, and another more sophisticated based on principal components analysis (PCA). The results are tested at the front door of the Arenberg Castle (Leuven, Belgium). Some moisture maps are derived and used to determine the reliability of either the computation of image differences or the PCA to carry out semi-automatically moisture surveys on architectural façades. The latter method is proven to be superior when using thermal imagery acquired at different times. 相似文献
46.
A model in which perceived overload and burnout mediated the relations of workload and autonomy with physicians' quality of care to their patients was examined. The study was based on data from 890 specialists representing six medical specialties. Including global burnout as well as its three first-order facets of physical fatigue, cognitive weariness, and emotional exhaustion improved the fit between the structural model and the data relative to an alternative model that included only global burnout. Workload (number of work hours) indirectly predicted quality of care through perceived overload. Additionally, the authors found that the paths from the first order factors of emotional exhaustion, physical fatigue, and cognitive weariness predicted quality of care negatively, positively, and nonsignificantly, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
Miriam Amo Fernando Martínez Margarita Torre 《IEEE transactions on image processing》2006,15(5):1192-1201
In this paper, we present a user-guided method based on the region competition algorithm to extract roads, and therefore we also provide some clues concerning the placement of the points required by the algorithm. The initial points are analyzed in order to find out whether it is necessary to add more initial points, and this process will be based on image information. Not only is the algorithm able to obtain the road centerline, but it also recovers the road sides. An initial simple model is deformed by using region growing techniques to obtain a rough road approximation. This model will be refined by region competition. The result of this approach is that it delivers the simplest output vector information, fully recovering the road details as they are on the image, without performing any kind of symbolization. Therefore, we tried to refine a general road model by using a reliable method to detect transitions between regions. This method is proposed in order to obtain information for feeding large-scale Geographic Information System. 相似文献
48.
63 mothers and their 3-day-old infants were observed during breast feeding. The analysis of dyadic vocal interaction suggested that during the neonatal period, the infant's vocalization is already responsive to both presence and absence of maternal vocalization. Maternal vocalization was shown to be responsive to antecedent vocal behavior of the newborn. No sex differences were found in the patterns of sequential vocal exchanges at this period. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
49.
Cohen M Joester D Geiger B Addadi L 《Chembiochem : a European journal of chemical biology》2004,5(10):1393-1399
A new concept that attributes a pivotal role to the pericellular coat in the regulation of the early stages of cell adhesion is presented. Quick, adaptable, and transient adhesion through multiple cooperative weak interactions provides the cell with an additional level of modulation in the decision-making process that precedes the commitment to adhesion at a particular site. Hyaluronan emerges as a modulator of cell adhesion in certain cells, mediating binding or repulsion through its polyelectrolyte character, in addition to its chirality and molecular-recognition properties. The biophysical properties of hyaluronan as well as its ultrastructural organization are analyzed in relation to this proposed function. 相似文献
50.
Breunig M Lungwitz U Klar J Kurtz A Blunk T Goepferich A 《Journal of nanoscience and nanotechnology》2004,4(5):512-520
For non-viral gene delivery, the carriers for DNA transfer into cells must be vastly improved. The branched cationic polymer polyethylenimine has been described as an efficient gene carrier. However, polyethylenimine was demonstrated to mediate substantial cytotoxicity. Therefore, this study is aimed at investigating per-N-methylated polyethylenimine, which is thought to have a much lower cytotoxicity due to its lower charge density. Results from a gel retardation assay and laser light scattering indicated that per-N-methylated polyethylenimine condenses DNA into small and compact nanoparticles with a mean diameter <150 nm. Furthermore, polyplexes of polyethylenimine and per-N-methylated polyethylenimine with DNA had a positive zeta potential and the polymers protected DNA from nuclease-mediated digestion. The transfection efficiency of polyethylenimine and per-N-methylated polyethylenimine was tested in CHO-K1 cells. Using green fluorescent protein as reporter gene and flow cytometry analysis, we demonstrated that per-N-methylated polyethylenimine has a lower cytotoxicity, but also a significantly lower transfection efficiency. Using propidium iodide staining, we could additionally distinguish between viable and dead cells. At NP > or = 12, per-N-methylated polyethylenimine showed a much higher cell viability and the ratio of viable and transfected cells to dead and transfected cells was about 1.5 to 1.7 fold higher than for polyethylenimine. The results of cell viability from flow cytometry analysis were confirmed by the MTS assay. Using luciferase reporter gene for transfection experiments, the gene expression of per-N-methylated polyethylenimine was lower at NP 6, 12 and 18 as compared to polyethylenimine, but at NP 24 it yielded similar levels. 相似文献