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61.
A. Ali J.G. Körner Z. Kunszt J. Willrodt G. Kramer G. Schierholz E. Pietarinen 《Physics letters. [Part B]》1979,82(2):285-288
We investigate the four-jet production processes in lowest order QCD perturbation theory. We estimate that four-jet events should be detectable at a rate of about 5% at the highest PETRA energy. The acoplanarity distribution is calculated and compared to nonperturbative effects. 相似文献
62.
Fabian Gyger André Sackmann Michael Hübner Pascal Bockstaller Dagmar Gerthsen Henning Lichtenberg Jan‐Dierk Grunwaldt Nicolae Barsan Udo Weimar Claus Feldmann 《Particle & Particle Systems Characterization》2014,31(5):591-596
Pd@SnO2 and SnO2@Pd core@shell nanocomposites are prepared via a microemulsion approach. Both nanocomposites exhibit high‐surface, porous matrices of SnO2 shells (>150 m2 g?1) with very small SnO2 crystallites (<10 nm) and palladium (Pd) nanoparticles (<10 nm) that are uniformly distributed in the porous SnO2 matrix. Although similar by first sight, Pd@SnO2 and SnO2@Pd are significantly different in view of their structure with Pd inside or outside the SnO2 shell and in view of their sensor performance. As SMOX‐based sensors (SMOX: semiconducting metal oxide), both nanocomposites show a very good sensor performance for the detection of CO and H2. Especially, the Pd@SnO2 core@shell nanocomposite is unique and shows a fast response time (τ90 < 30 s) and a very good response at low temperature (<250 °C), especially under humid‐air conditions. Extraordinarily high sensor signals are observed when exposing the Pd@SnO2 nanocomposite to CO in humid air. Under these conditions, even commercial sensors (Figaro TGS 2442, Applied Sensor MLC, E2V MICS 5521) are outperformed. 相似文献
63.
K. Ahrens A. Kramer 《International Journal of Mathematical Education in Science & Technology》2013,44(4):618-624
This paper proves that the ratios of consecutive terms of the m-bonacci sequence converge to a limit φm < 2 and, as m → ∞, these φm converge to 2. Further, it is shown that the generating functions for the m-bonacci sequences converge pointwise to the geometric series. 相似文献
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Karel Kolomazník Ji?í Pecha Veronika Friebrová Dagmar Janá?ová Vladimír Va?ek 《Heat and Mass Transfer》2012,48(9):1505-1512
Biostimulators are substances able to enhance the immune system of cultivated crops and support plant metabolism. Their utilization helps to reduce the amount of chemicals used in agriculture. To perform the desired effect, a biostimulator must be able to penetrate into the plant tissue. The time of penetration however, is limited, since the biostimulator must remain in a liquid state. This is of great importance—especially in field conditions, where the treated plants are exposed to different weather condition and other extrinsic factors. A mathematical model based on diffusion mechanisms has been elaborated to describe the biostimulator transport process from penetration of the leaves into the plant’s inner tissues. By means of the effective diffusion coefficient of the prepared specific protein hydrolyzate, this model can be used to estimate the time necessary for the uptake of the minimal active amount of the biostimulator. 相似文献
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Vladislava Mičková Silvia Ružičková Dagmar Remeteiová Martina Laubertová Marianna Dorková 《Chemical Papers》2018,72(5):1231-1238
Sampling is the most important procedure in arriving at the value of an electronic scrap. Inappropriate sampling makes other procedures, including assaying, valueless, as the sample must really represent the electronic scrap from which it was taken. The aim of this study was to develop the procedure to investigate the composition of heterogeneous printed circuit boards (PCBs) material and to show its applicability as well as its related limitations. The contents of Cu, Pb, Ni, and Zn in PCBs from wasted mobile phones were determined. Mixtures of aqua regia, hydrogen peroxide and hydrofluoric acid were applied to sample digestion. Open and closed vessel wet digestion with or without heating and microwave-assisted one was realized. For these purposes different sample amounts (0.2, 0.4, and 0.5 g) were applied and on the basis of calculated relative standard deviation values (RSD), the precision of repeated the most effective digestion was evaluated. The microwave-assisted wet digestion and mixture of aqua regia and hydrogen peroxide was found as the most effective one of the compared mixtures and applied conditions. A sample amount of 0.5 g was found as the most suitable. RSD values confirm the importance of electronic waste material sample preparation. 相似文献
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