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111.
Rob H. Nibbelke Arthur J. L. Nievergeld Jozef H. B. J. Hoebink Guy B. Marin 《Applied catalysis. B, Environmental》1998,19(3-4):245-259
A transient kinetic model was developed for the CO oxidation by O2 over a Pt/Rh/CeO2/γ-Al2O3 three-way catalyst. The experiments which were modelled consisted of periodically switching between a feed stream containing 0.5 mol% CO in helium and a feed stream containing 0.5 mol% O2 in helium, with a frequency from 0.1 to 0.25 Hz, in the temperature range 393–433 K. These temperatures are representative for cold start conditions. The transient experiments yield information about the reaction mechanism. A transient kinetic model based on elementary reaction steps was developed which describes the experimental data in the above mentioned range of experimental conditions adequately. The kinetic model consists of two monofunctional and one bifunctional contribution. The first monofunctional reaction path comprises competitive adsorption of CO and O2 on the noble metal surface followed by a surface reaction. The second monofunctional reaction path consists of CO adsorption on an oxygen atom adsorbed on the noble metal surface, followed by a reaction to CO2. The bifunctional reaction path involves a reaction between CO adsorbed on the noble metal surface and oxygen from ceria at the noble metal/ceria interface. Also, reversible adsorption of carbon dioxide on the support is taken into account. The kinetic parameters, i.e. preexponential factors and activation energies for the different elementary reaction steps, and the oxygen storage capacity were estimated using multi-response non-linear regression analysis of the oxygen, carbon monoxide and carbon dioxide outlet concentrations. 相似文献
112.
113.
1 INTRODUCTIONBiosorption of heavy metals using biosorbents derived from suitable biomass is a new tech-nology for the removal and recovery of heavy metals from industrial waste waters.The ad-vantages of the biosorption technology include rapid reduction of dissolved heavy metal ionsconcentration to 10~(-6)and 10~(-9)levels,use of inexpensive and non-hazardous biosorbents,useof existing adsorption process equipment and therefore low operating costs,high uptake ca-pacity and specificity for selective heavy metal removals,and low interference from other 相似文献
114.
Jozef Hooman 《Real-Time Systems》1994,6(2):173-205
A distributed real-time arbitration protocol is specified and verified using an assertional method. The formalism is based on classical Hoare triples which have been extended to deal with real-time properties. To verify design steps, a compositional proof system has been formulated for these extended triples. The intention of the protocol is to resolve contention between a number of concurrent modules that compete to acquire control of a common bus. Therefore our proof method has been adapted to deal with concurrent processes that communicate by means of a common bus. Compositionality makes it possible to verify the required properties of the protocol using only the specifications of the modules. Next we give a top-down derivation of a program implementing a module according to its real-time specification. 相似文献
115.
A one-step procedure for the preparation of (E)-2-nonenal from commercial castor oil by ozonolysis in acetic acid, followed by exposure of the resulting intermediate product
top-toluene sulfonic acid, is described. The manufactured aldehyde is of high purity and the method, by virtue of being simple
and using inexpensive raw material, has advantages over those reported in the literature. 相似文献
116.
矿井自然灾害之间的相互影响及防治措施的应用效果评估对矿井安全生产具有很重要的意义。准确预测矿井灾害状态和防治措施的效果取决于对它们的详细描述,而提高其描写的准确性可采用模糊数学的方式。介绍了自然灾害和防治措施实施效果评估的模糊数学模型。 相似文献
117.
Parameter identification of Wiener systems with multisegment piecewise-linear nonlinearities 总被引:2,自引:0,他引:2
Jozef Vrs 《Systems & Control Letters》2007,56(2):99-105
118.
Lis J Pasieczna A Karbowska B Zembrzuski W Lukaszewski Z 《Environmental science & technology》2003,37(20):4569-4572
Thallium was determined in 120 samples of soil and 30 samples of stream sediments from the southeastern part of the Silesian-Cracowian zinc-lead ore deposits. Soil samples were taken from topsoils (0.0-0.2 m) and bottom soils (0.8 and 1.0 m). Thallium was determined by flow-injection-differential-pulse anodic stripping voltammetry. The samples were decomposed sequentially with 73% hydrofluoric acid and a mixture of nitric acid and hydrogen peroxide. The results showed that zinc-lead ore mining as well as their processing and smelting leads to a significant increase of thallium in the top layer of soil and in stream sediments. The highest recorded concentration was 150 ppm Tl for stream sediment and 35 ppm for a soil sample. Thallium concentration in small rivers from the investigated area was by 2 orders of magnitude higher than in the reference area. The highest recorded concentration being 3.24 microg L(-1). 相似文献
119.
The broad‐line 1H‐NMR study of the polymer blend composed of isotactic polypropylene and ethylene–propylene–diene monomer rubber was carried out. The NMR measurements were performed on the samples of the polymer blend and on the components of the blend in the temperature range covering the glass‐transition regions of all studied polymers. Conclusions were drawn from the temperature dependencies of the second moment M2 and of the data obtained by the decomposition of the spectra into the components related to the motionally distinct regions of the partially crystalline polymer. The mass fractions of the amorphous, intermediate, and crystalline domains and the widths of the spectra related to the particular phases were computed from the spectra. A double glass transition was revealed for the polymer blend. Different mechanisms of the motional processes related to the glass transition were deduced from the data. The gradual increase of the number of the chains and the enhancement of the chain mobility within noncrystalline regions of the polymer blend are responsible for the motion related to the lower glass transition and only transformation of the hindered motion into free motion was found in the temperature region of the upper glass transition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 247–252, 2004 相似文献
120.
Several recent papers have documented observations of the "psychic" salivary secretion (a fortuitously conditioned reflex)--some as early as 1840--which preceded Pavlov's classical experiments in 1902. This note calls attention to Regnier De Graaf who utilized a "psychic" salivary secretion of a fistulated dog, and reported his findings in a publication dated December 17, 1664. De Graaf's drawing of his fistulated dog is argued to be one of the most interesting documents in the history of psychology, for it has a striking similarity to the numerous drawings of Pavlov's dog made more than 250 years later. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献