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排序方式: 共有292条查询结果,搜索用时 15 毫秒
101.
Le Giang H. Nguyen Tuan T. Nguyen Manh B. Quan Trang T. T. Nguyen Trinh Duy Sapi Andras Szenti Imre Mutyala Suresh Kukovecz Akos Konya Zoltan Vu Tuan A. 《Topics in Catalysis》2020,63(11-14):1314-1324
Topics in Catalysis - Fe/graphene oxide and Cu–Fe/graphene oxide nanocomposite were synthesized by the atomic implantation method to study the photocatalytic degradation of... 相似文献
102.
Petra S.Pálvölgyi Daniel Sebők Imre Szenti Eva Bozo Henri Ervasti Olli Pitkänen Jari Hannu Heli Jantunen Marko E.Leinonen Sami Myllymäki Akos Kukovecz Krisztian Kordas 《Nano Research》2021,14(5):1450-1456
In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10?4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band. 相似文献
103.
The compressive behaviour of eight different metal matrix syntactic foams (MMSFs) are investigated and presented. The results showed that the engineering factors as chemical compositions of the matrix material, the size of the microballoons, the previously applied heat treatment and the temperature of the compression tests have significant effects on the compressive properties. The smaller microballoons with thinner wall ensured higher compressive strength due to their more flawless microstructure and better mechanical stability. According to the heat treatments, the T6 treatments were less effective than expected; the parameters of the treatment should be further optimised. The elevated temperature tests revealed ∼30% drop in the compressive strength. However, the strength remained high enough for structural applications; therefore MMSFs are good choices for light structural parts working at elevated or room temperature. The chemical composition - microballoon type - heat treatment combinations give good potential for tailoring the compressive characteristics of MMSFs. 相似文献
104.
105.
Emborg J Matjačić Z Bendtsen JD Spaich EG Cikajlo I Goljar N Andersen OK 《IEEE transactions on bio-medical engineering》2011,58(4):960-970
A novel closed-loop system for improving gait in hemiparetic patients by supporting the production of the swing phase using electrical stimulations evoking the nociceptive withdrawal reflex was designed. The system exploits the modular organization of the nociceptive withdrawal reflex and its stimulation site- and gait-phase modulation in order to evoke movements of the hip, knee, and ankle joints during the swing phase. A modified model-reference adaptive controller (MRAC) was designed to select the best stimulation parameters from a set of 12 combinations of four electrode locations on the sole of the foot and three different stimulation onset times between heel-off and toe-off. It was hypothesized that the MRAC system would result in a better walking pattern compared with an open-loop preprogrammed fixed pattern of stimulation (FPS) controller. Thirteen chronic or subacute hemiparetic subjects participated in a study to compare the performance of the two control schemes. Both control schemes resulted in a more functional gait compared to no stimulation (P < 0.05) with a weighted joint angle peak change of 4.0 ± 1.6 (mean ± Standard deviation) degrees and 3.1 ± 1.4 degrees for the MRAC and FPS schemes, respectively. This indicates that the MRAC scheme performed better than the FPS scheme (P < 0.001) in terms of reaching the control target. 相似文献
106.
Darányi M Csesznok T Kukovecz A Kónya Z Kiricsi I Ajayan PM Vajtai R 《Nanotechnology》2011,22(19):195701
We report on the layer-by-layer (LbL) formation of TiO(2)-MWNT-TiO(2) coatings on quartz with either trititanate derived TiO(2) nanowires or Degussa P25 as the photocatalytically active material. The optimized deposition sequence is discussed in detail and the morphology of the prepared coatings is analyzed by SEM and XRD. The heterogeneous photocatalytic performance of the coatings was tested in the methyl orange oxidation reaction. The apparent first order rate constant fell in the 0.01-0.20 h(-1) range over a 2.5 × 2.5 cm(2) film depending on the type and the thickness of the titanate coating. Building a multiwall carbon nanotube layer into the middle of the layer improved the photocatalytic activity for each material for all of the studied thicknesses. P25 based films performed 2-5 times better than TiO(2) nanowire films; however, the pores in the P25 based films were largely blocked because the isotropic P25 nanoparticles form closely packed layers by themselves and even more so with the comparably sized multiwall carbon nanotubes. Therefore, films derived from titanate nanowires appear to be more suitable for use as multifunctional, photocatalytically active filtration media. 相似文献
107.
Aiqing Chen A. Eugene DePrince III Arnaud Demortière Alexandra Joshi‐Imre Elena V. Shevchenko Stephen K. Gray Ulrich Welp Vitalii K. Vlasko‐Vlasov 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(16):2365-2371
The cost‐effective self‐assembly of 80 nm Au nanoparticles (NPs) into large‐domain, hexagonally close‐packed arrays for high‐sensitivity and high‐fidelity surface‐enhanced Raman spectroscopy (SERS) is demonstrated. These arrays exhibit specific optical resonances due to strong interparticle coupling, which are well reproduced by finite‐difference time‐domain (FDTD) simulations. The gaps between NPs form a regular lattice of hot spots that enable a large amplification of both photoluminescence and Raman signals. At smaller wavelengths the hot spots are extended away from the minimum‐gap positions, which allows SERS of larger analytes that do not fit into small gaps. Using CdSe quantum dots (QDs) a 3–5 times larger photoluminescence enhancement than previously reported is experimentally demonstrated and an unambiguous estimate of the electromagnetic SERS enhancement factor of ≈104 is obtained by direct scanning electron microscopy imaging of QDs responsible for the Raman signal. Much stronger enhancement of ≈108 is obtained at larger wavelengths for benzenethiol molecules penetrating the NP gaps. 相似文献
108.
Imre Blank Karl-Heinz Fischer Werner Grosch 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,189(5):426-433
Summary Aroma extract dilution analysis of linden honey volatiles resulted in 21 odour compounds having high factors of dilution (FD); 18 of these compounds were identified as 1-hexen-3-one, 2-acetyl-1 -pyrroline, dimethyl trisulphide, methional, phenylacetaldehyde, 2-phenylethanol, linalool, p-cresol, 3,9-epoxy-lpmenthene, 4-methylacetophenone, 3,9-epoxy-1,4(8)-p-menthadiene (linden ether), 1,3 p-menthadien-7-al, p-anisaldehyde, 4vinylguaiacol, (E)-p-damascenone, eugenol, vanillin andcis-rose oxide. Linden ether andcis-rose oxide, which were also found in an extract obtained from the blossoms of the lime tree (Tifa cordata), were absent in honeys of other botanical origin. These two odourants and the odourlesstrans-limonene-1,2-diol are proposed as indicators for linden honey. The odour thresholds (in air) of the 18 aroma compounds are reported.
Intensive neutrale Geruchsstoffe von Lindenhonig. Unterschiede zu Honigen anderer botanischer Herkunft
Zusammenfassung Die Aromaextrakt-Verdünnungs-analyse der flüchtigen Verbindungen aus Lindenhonig ergab 21 Geruchsstoffe mit hohen FD-Faktoren; 18 davon wurden identifiziert: l-Hexen-3-on, 2-Acetyl-1 -pyrrolin, Dimethyltrisulfid, Methional, Phenylacetaldehyd, 2-Phenylethanol, Linalool, p-Kresol, 3,9-Epoxy-1 p-menthen, 4-Methylacetophenon, 3,9-Epoxy-1,4(8)p-menthadien (Lindenether), 1,3 -p-Menthadi-en-7-al,p-Anisaldehyd, 4-Vinylguajacol, (E)--Da-mascenon, Eugenol, Vanillin undcis-Rosenoxid. Lindenether undcis-Rosenoxid, die auch in einem Extrakt von Lindenblüten (Tilla cordata) vorkamen, fehlten in Honigen anderer botanischer Herkunft. Diese beiden Aromastoffe und das geruchlosetrans-Limonen-1,2-diol werden als Indikatoren für Linden honig vorgeschlagen. Die Geruchsschwellen (in Luft) der 18 Aromastoffe wurden bestimmt.相似文献
109.
Imre Blank Alina Sen Werner Grosch 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1992,195(3):239-245
Summary Aroma extract dilution analysis (AEDA) revealed 13 compounds as important contributors to the aroma of roasted coffee (powder): 2-methyl-3-furanthiol (I), 2-furfurylthiol (II), methional (III), 3-mercapto-3-methylbutylformate (IV), 3-isopropyl-2-methoxypyrazine (V), 2-ethyl-3,5-dimethylpyrazine (VI), 2,3-diethyl-5-methylpyrazine (VII), 3-isobutyl-2-methoxy-pyrazine (VIII), 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon, IX), 4-ethylguaiacol (X), 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (XI), 4-vinylguaiacol (XII), and (E)--damascenone (XIII). A comparative AEDA of the coffee powder and brew showed in the brew an increase of III, IX, vanillin and 4-hydroxy-2,5-dimethyl-3(2H)-furanone and a decrease of I, II, IV, V, VII, and VIII.
Results presented in part at the 14th International Conference on Coffee Science, San Francisco, USA (July 14–19, 1991) 相似文献
Intensive Geruchsstoffe von Röstkaffee und Röstkaffeeaufguß aus Arabica-Kaffee
Zusammenfassung Die Aromaextrakt-Verdünnungsanalyse (AEVA) von Röstkaffee ergab 13 wichtige Geruchsstoffe: 2-Methyl-3-furanthiol (I), 2-Furfurylthiol (II), Methional (III), 3-Mercapto-3-methylbutylformiat (IV), 3-Isopropyl-2-methoxypyrazin (V), 2-Ethyl-3,5-dimethylpyrazin (VI), 2,3-Diethyl-5-methylpyrazin (VII), 3-Isobutyl-2-methoxypyrazin (VIII), 3-Hydroxy-4,5-dimethyl-2(5H)-furanon (Sotolon, IX), 4-Vinylguajacol (XII) und (E)--Damascenon (XIII). Die vergleichende AEVA von Röstkaffee und daraus hergestelltem Aufguß zeigte im Aufguß eine Zunahme von III, IX, Vanillin und 4-Hydroxy-2,5-dimethyl-3(2H)-furanon und eine Abnahme von I, II, IV, V, VII und VIII.
Results presented in part at the 14th International Conference on Coffee Science, San Francisco, USA (July 14–19, 1991) 相似文献
110.
A coefficient of restitution of rock materials 总被引:2,自引:0,他引:2
At a macroscopic scale, even a purely elastic contact between rock particles is accompanied by energy dissipation. The resulting hysteretic loop of the stress/strain path during such a loading and unloading event suggests that grains recover slower to their original shape than when they were first deformed. This contact behaviour may be simulated in distinct element codes by utilizing a hysteretic damping contact model. In this research, values for the elastic coefficient of restitution for components of a molasse conglomerate were measured using a newly developed drop-test apparatus. These values can be used to calibrate or to verify constitutive models that incorporate strain-rate-independent, elastic hysteretic damping. 相似文献