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111.
Future Internet has become the federating theme for European research on communication networks and services. At the core lies research on communication networks toward an efficient, scalable, and reliable future Internet coupled with research on the underlying technologies, in particular mobile and wireless access and optical networks. This article first presents the motivation for a bold initiative for future Internet research in Europe. In this context a changing business environment for telecommunications and the Internet, and the opportunities to provide future Internet services are discussed. From a technical perspective the limitations of the current Internet technology are outlined. The research activities that address the challenge of future Internet research are introduced under three main lines: future Internet architecture and network technologies, spectrum-efficient access to future networks, and converged infrastructures in support of future networks. Examples of the first promising approaches to significantly change the principles of the Internet architecture and protocols are presented. 相似文献
112.
Michel S. J. Steyaert Stefan Gogaert Wim Dehaene José Silva-martinez Jan Sevenhans 《电信纪事》1993,48(3-4):224-232
This paper describes full cmoscontinuous time filter design techniques which can meet the specifications commonly set for gsmapplications. First several cmosfilter design techniques are overviewed. The ota-ctechnique is discussed to some more detail. To overcome the main drawback of the lower total harmonic distortion in ota-ctechniques very linear operational transconductance amplifiers (ota)are required. Such an ota,together with the applied linearisation techniques is discussed. To fulfil high accuracy in cut- off frequencies of the filter an active tuning system is necessary. A new on- chip tuning system is presented. The paper concludes with a practical design example for the gsmsystem. Therein the different ota-ctechniques discussed are illustrated. 相似文献
113.
Hydrogen energy from coupled waste gasification and cement production—a thermochemical concept study
A plant concept for hydrogen production from waste gasification coupled with cement manufacturing is presented. Hot precalcined cement meal, from the operating cement process, is used as heat carrier to provide energy required by the parallel arranged gasifier. The amount of CaO present in the cement meal operates simultaneously as an effective in situ CO2-sorbent. First, a practical case study was devised to be able to perform simulations for estimation of expected hydrogen yield. The influence of different operation parameters of the gasifier and the hydrogen separation unit (steam-to-fuel ratio, pyrolysis temperature, PSA efficiency) was studied based on chemical equilibrium calculations. The simulation results indicate, that the coupling provides advantages for both processes. The production of a hydrogen-rich gas via thermal gasification benefits from the continuously available fresh CaO, which improves fuel conversion reactions and captures CO2 in situ. High-calorific streams from gasification process remaining after hydrogen separation may substitute fossil fuels needed for cement process. For a steam/fuel ratio of 0.3 and a PSA efficiency of 0.7, the calculated hydrogen energy yield is 46% of fuel energy input. 相似文献
114.
Stefan Vieths Werner Blaas Manfred Fischer Christian Krauses Reinhard Matissek Irena Mehlitz und Rudolf Weber 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1988,186(5):393-397
Zusammenfassung Lebensmittel, die im Emissionsbereich Chemischer Reinigungen gelagert bzw. verkauft werden, können erheblich mit Tetrachlorethen belastet sein. Hohe Tetrachlorethengehalte wurden sowohl in Lebensmittelproben aus über Chemischen Reinigungen gelegenen Wohnungen als auch in Proben aus dem Lebensmitteleinzelhandel festgestellt. Lebensmittel mit hohem Fettgehalt wiesen stets die höchsten Kontaminationen auf.
Contamination of foodstuffs by emissions from dry cleaning units
Summary Tetrachloroethene (perchloroethylene) from dry-cleaning units may contaminate adjacent flats in the same building. Increased concentrations of tetrachloroethene have been found in foodstuffs in homes situated above dry cleaning units and in foodstuffs from groceries located neat drycleaning units. The concentrations were extremely high in foods rich in fat.相似文献
115.
Summary Living cationic polymerization of isobutul vinyl ether (IBVE), initiated by1-iodo-1-(2-methyl propyloxy)-ethane (1) and tetraalkylammonium perchlorate yields polymers of well defined molar masses and end groups. The controlled introduction of end groups was confirmed by a model reaction and was then applied to introduce and azo initiator function. The resulting polymeric initiator was used for the synthesis of a blockcopolymer. 相似文献
116.
Stefan Schulz Wittko Francke Wilfried A. König Volker Schurig Kenji Mori Rolf Kittmann Dietrich Schneider 《Journal of chemical ecology》1990,16(12):3511-3521
(R)-6-Ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3. 1]non-7-ene, and (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3.1]non-7-en-6-one represent the main components in the male pheromone of the swift moth,Hepialus hecta. The amounts of the three components were 40, 5, and 5 g per male, respectively. Structure elucidation of the compounds was based on spectroscopic data as compared to synthetic reference samples. The absolute configurations were determined by gas chromatography on chiral stationary phases; optically active samples served as reference compounds. Electrophysiological and behavioral experiments with natural material and synthetic samples clearly showed the three heterocyclic compounds to act as pheromones. (E, E)--Farnesene represents the main component of the scent secretion of maleHepialus humuli. 相似文献
117.
Vuchinich Rudy; Wallace Dennis; Milby Jesse B.; Schumacher Joseph E.; Mennemeyer Stephen; Kertesz Stefan 《Canadian Metallurgical Quarterly》2009,17(3):165
Clinical trials with cocaine-dependent outpatients have found a strong relation between in-treatment and follow-up abstinence, and the strength of this relation is constant across treatment conditions with variable efficacy in generating abstinence. The authors conducted secondary analyses of data from 3 clinical trials to determine whether this relation generalizes to cocaine-dependent homeless persons. The 3 trials (total N = 543) were conducted in a community health care facility for homeless people. The 7 treatment arms across the 3 trials were combinations of day treatment, abstinence-contingent housing, and vocational training. Drug use was measured with urine toxicology testing. Consecutive weeks of abstinence during treatment were strongly related to abstinence at the 12-month follow-up, whether or not missing 12-month data were included in the analysis. The treatment arms differed in their efficacy in generating abstinence, but the relation between in-treatment and follow-up abstinence did not differ across treatment arms. These results replicate earlier reports of these relations and extend them to a population of homeless people. The lack of differences between treatment arms in the in-treatment–follow-up abstinence relation implies that that relation is independent of the treatment-specific intervention components that generate group differences in abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
118.
119.
Stefan M. Holzer 《Bautechnik》2015,92(3):230-237
120.
Functionalized galactoglucomannan‐based hydrogels for the removal of metal cations from aqueous solutions 下载免费PDF全文
Elizabeth Elgueta Julio Sánchez Daniel Dax Chunlin Xu Stefan Willför Bernabé L Rivas Marianela González 《应用聚合物科学杂志》2016,133(41)
New types of hydrogels derived from O‐acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44093. 相似文献