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101.
102.
Schaefer-Sindlinger A. Lappas I. Vogt C. D. Ito T. Kurachi H. Makino M. Takahashi A. 《Topics in Catalysis》2007,42(1-4):307-317
This paper will give an overview about the filter development for diesel particulate emission control in automotive applications.
The material development for passenger car diesel particulate filters led to new materials like silicon carbide while for
heavy duty applications still Cordierite plays a major role. But in the future other materials might also be used for passenger
cars. This paper will show the basic difference between both applications and describe the material design in terms of filter
properties (base material, back pressure aspects, filtration efficiency, coating impact). Current application on vehicles
with catalysed soot filters (CSF) with and without oxidation catalyst will be presented. Furthermore an outlook will be given
on materials for catalysed soot filters for the future. 相似文献
103.
采用高压催化剂性能评价实验装置,在压力分别为7.0,10.0和15.0MPa,温度分别为350,400和450℃条件下,在H2/N2为1.6-3.0范围内研究了H2/N2对A301,ZA-5和A110-2型催化剂的活性和合成塔出口氨浓度的影响。在压力和空速一定的条件下,最佳H2/N2随反应温度而异。在350,400和450℃下,最佳H2/N2分别为1.8-2.2,2.2-2.5和2.5-3.0。由此可见,合成氨反应的速率达到最大值时的最佳H2/N2值与反应的进程有关。为此提出了催化剂效率K(Catalysis efficiency)的概念来表征在催化剂作用下反应器出口氨浓度趋近平衡的程度,即K=CNH3/C^*NH3。根据实验结果,得到了最佳H2/N2与催化剂效率的定量关系:(H2/N2)m=1.5(1 CNH3/C^*NH3)=1.5(1 K)。由此可以根据催化剂在不同反应条件下的催化剂效率来确定最佳H2/N2。凡是会降低催化剂效率的因素,都会使最佳H2/N2降低。各种影响因素对最佳H2/N2的影响中,反应温度的影响最大,其次是空速和催化剂的活性,而压力和惰性气体含量的影响相对较小。在低温(低压)下合成氨,宜采用较低的H2/N2。 相似文献
104.
105.
J. H. M. Scholten 《Nutrient Cycling in Agroecosystems》1992,33(2):107-114
To increase the fertilizer-N efficiency in lowland rice (Oryza sativa L.) cultivation, new management practices are needed. Main cause of the present low efficiency is the low N recovery by plants, as a considerable part of the N applied is lost; deep placement techniques improve the recovery. A pneumatic injector, with which urea prills can be point-placed at a depth of 5–10 cm in paddy soils, was tested in 38 on-farm trials in 1989/90, mostly during the wet season. The experiments, located in Africa and Asia, focussed on differences in grain yield between conventional methods of broadcasting urea and injection by the pneumatic injector, at recommended N-rates. The study shows that the pneumatic injector is effective as a tool to improve the N fertilizer efficiency. The average yield increases per region, resulting from the use of the injector, ranged from about 250 to 1300 kg grain ha–1. The value of the yield increase would allow most farmers to recover the costs of the injector within one season, even if labour was hired to carry out the injections. The average labour requirement of the injector was 40 hours ha–1. In Indonesia, injection of prilled urea gave yields similar to those obtained with urea briquettes. 相似文献
106.
C. Tuve' R. Potenza M. Chiorboli M.G. Grimaldi F. La Rosa F. Raimondo M. Marinelli E. Milani A. Tucciarone G. Verona Rinati M. Donato G. Faggio G. Messina S. Santangelo G. Pucella 《Diamond and Related Materials》2006,15(11-12):1986
Polycrystalline (pCVD) and single crystal (scCVD) diamond films grown from Chemical Vapour Deposition (CVD), if sufficiently pure at Raman analysis, are very good materials for beam or flux monitors inside accelerators or nuclear reactors. This is because they are very hard to damage in high radiation fields and very resistant to high temperatures. Films of pCVD diamond are, however, not so good as spectroscopy detectors due to inhomogeneities induced by their growth in grains with the consequent presence of grain boundaries which worsen their energy resolution. The latter can be significantly improved by growing scCVD diamond films onto HPHT synthetic diamond substrates. We have shown that it is possible to measure the density of defects inside diamond specimens using as probes suitable penetrating nuclear radiations. With the preliminary results reported here we'll show that, bombarding CVD diamond films grown at Roma “Tor Vergata” with energetic protons and 4He, 6Li and 12C ions produced in the accelerators of Catania laboratories, the pulse height defects are higher than those in silicon detectors and likewise well described by a power law in the deposited energy. Furthermore, we'll show that pulse heights for the same particles seem to depend on the duration of the measurement, thus exhibiting a sort of depolarization of the insulator when exposed to the electric voltage which makes it a particle detector. 相似文献
107.
The design of barbotage‐rotation installation with different profiles of blades of the rotator has been created on the basis of modeling method. As a result of the complexity of aerohydrodynamic research in the system “gas–liquid” carried out on the aforementioned unit, certain recommendations on the improvement of the construction and operating conditions have been developed with a view to rise the effectiveness of dust removal. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3357–3360, 2006 相似文献
108.
109.
110.
The oxidation of acetaldehyde on carbon supported Pt/Vulcan, PtRu/Vulcan and Pt3Sn/Vulcan nanoparticle catalysts and, for comparison, on polycrystalline Pt and on an unsupported PtRu0.2 catalyst, was investigated under continuous reaction and continuous electrolyte flow conditions, employing electrochemical and quantitative differential electrochemical mass spectroscopy (DEMS) measurements. Product distribution and the effects of reaction potential and reactant concentration were investigated by potentiodynamic and potentiostatic measurements. Reaction transients, following both the Faradaic current as well as the CO2 related mass spectrometric intensity, revealed a very small current efficiency for CO2 formation of a few percent for 0.1 m acetaldehyde bulk oxidation under steady-state conditions on all three catalysts, the dominant oxidation product being acetic acid. Pt alloy catalysts showed a higher activity than Pt/Vulcan at lower potential (0.51 V), but do not lead to a better selectivity for complete oxidation to CO2. C–C bond breaking is rate limiting for complete oxidation at potentials with significant oxidation rates for all three catalysts. The data agree with a parallel pathway reaction mechanism, with formation and subsequent oxidation of COad and CH
x, ad species in the one pathway and partial oxidation to acetic acid in the other pathway, with the latter pathway being, by far, dominant under present reaction conditions. 相似文献