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1.
Various spinel-type catalysts AB2O4 (where A = Mg, Ca, Mn, Co, Ni, Cu, Cr, Fe, Zn and B = Cr, Fe, Co) were prepared and characterized by XRD, BET, TEM and FESEM-EDS. The performance of these catalysts towards the decomposition of N2O to N2 and O2 was evaluated in a temperature programmed reaction (TPR) apparatus in the absence and the presence of oxygen. Spinel-type oxides containing Co at the B site were found to provide the best activity. The half conversion temperature of nitrous oxide over the MgCo2O4 catalyst was 440 °C and 470 °C in the absence and presence of oxygen, respectively (GHSV = 80,000 h−1).

On the grounds of temperature programmed oxygen desorption (TPD) analyses as well as of reactive runs, the prevalent activity of the MgCo2O4 catalyst could be explained by its higher concentration of suprafacial, weakly chemisorbed oxygen species, whose related vacancies contribute actively to nitrous oxide catalytic decomposition. This indicates the way for the development of new, more active catalysts, possibly capable of delivering at low temperatures amounts of these oxygen species even higher than those characteristic of MgCo2O4.  相似文献   

2.
Currently,sorafenib is the only systemic therapy capable of increasing overall survival of hepatocellular carcinoma patients.Unfortunately,its side effects,particularly its overall toxicity,limit the therapeutic response that can be achieved.Superparamagnetic iron oxide nanoparticles (SPIONs) are very attractive for drug delivery because they can be targeted to specific sites in the body through application of a magnetic field,thus improving intratumoral accumulation and reducing adverse effects.Here,nanoformulations based on polyethylene glycol modified phospholipid micelles,loaded with both SPIONs and sorafenib,were successfully prepared and thoroughly investigated by complementary techniques.This nanovector system provided effective drug delivery,had an average hydrodynamic diameter of about 125 nm,had good stability in aqueous medium,and allowed controlled drug loading.Magnetic analysis allowed accurate determination of the amount of SPIONs embedded in each micelle.An in vitro system was designed to test whether the SPION micelles can be efficiently held using a magnetic field under typical flow conditions found in the human liver.Human hepatocellular carcinoma (HepG2) cells were selected as an in vitro system to evaluate tumor cell targeting efficacy of the superparamagnetic micelles loaded with sorafenib.These experiments demonstrated that this delivery platform is able to enhance sorafenib's antitumor effectiveness by magnetic targeting.The magnetic nanovectors described here represent promising candidates for targeting specific hepatic tumor sites,where selective release of sorafenib can improve its efficacy and safety profile.  相似文献   
3.
This article reports the findings of a user study conducted in the context of the TELplus project to gain insights about user needs and preferences for the digital library services offered by The European Library Web portal. The user requirements collection for the Web portal was designed by adopting a comprehensive survey approach. This combined explicit user feedback with implicit usage data so as to provide a more in-depth analysis of user experience with the portal. The analysis conducted shed light on likely motivations for both participant usage and reluctance to use the services provided, leading to more informed decisions on how to refine, improve, and present Web portal services to their future users. The lessons learnt from this case study also contributed to the development of an integrated methodological framework which provided insights for the future design and evaluation of digital library Web portals and services.  相似文献   
4.
The Palearctic planthopper Hyalesthes obsoletus is the natural vector of the grapevine yellow disease Bois noir. Grapevine is an occasional host plant of this polyphagous planthopper. To deepen our knowledge of the role of plant volatile organic compounds for H. obsoletus host plant searching, we carried out behavioral, morphological, and electrophysiological studies. We tested the attraction of H. obsoletus to nettle, field bindweed, hedge bindweed, chaste tree, and grapevine by using a Y-shaped olfactometer. The results showed a significant attraction of male H. obsoletus to chaste tree, and of the females to nettle. Male H. obsoletus were repelled by odor from hedge bindweed. Ultrastructural studies of the antennae showed at least two types of olfactory sensilla at the antennal pedicel: plaque organs and trichoid sensilla. Volatile organic compounds from nettle and chaste tree were collected, and the extracts were analyzed by coupling gas-chromatography to both mass-spectrometry and electroantennography. The volatile organic compounds that elicited electrophysiological responses in male and female antennae were identified. These findings are discussed with respect to behavior of H. obsoletus males and females in the field.  相似文献   
5.
In this contribution, we report on the solid-state-photodynamical properties and further applications of a low dimensional composite material composed by the luminescent trans-4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) dye interacting with a two-dimensional-metal organic framework (2D-MOF), Al-ITQ-HB. Three different samples with increasing concentration of DCM are synthesized and characterized. The broad UV-visible absorption spectra of the DCM/Al-ITQ-HB composites reflect the presence of different species of DCM molecules (monomers and aggregates). In contrast, the emission spectra are narrower and exhibit a bathochromic shift upon increasing the DCM concentration, in agreeance with the formation of adsorbed aggregates. Time-resolved picosecond (ps)-experiments reveal multi-exponential behaviors of the excited composites, further confirming the heterogeneous nature of the samples. Remarkably, DCM/Al-ITQ-HB fluorescence is sensitive to vapors of electron donor aromatic amine compounds like aniline, methylaniline, and benzylamine due to a H-bonding-induced electron transfer (ET) process from the analyte to the surface-adsorbed DCM. These findings bring new insights on the photobehavior of a well-known dye when interacting with a 2D-MOF and its possible application in sensing aniline derivatives.  相似文献   
6.
In order to complete the transesterification process, online result verification is applied to the traditional offline verification process based on chromatographic methods. There is a quick analytical method for assessing the biodiesel content of transesterification reaction by applying a correlation with viscosity. The results can substitute chromatographic verifications when recognizing and selecting the specified biodiesel quality. This type of verification could save hours of biodiesel process production per day. The proposed work designs a control solution for online biodiesel production verification using an online application based on the PNN technology and Coriolis viscosity sensors.  相似文献   
7.
Contents The paper describes an analytical three-dimensional method which allows the determination of the propulsion force produced by air core long stator linear synchronous motors in EDS-MAGLEV transport systems, using super-conducting coils both for motor field winding and for vehicle levitation. The method, which allows to take into account the finite thickness of the coils, is based on the variation of the magnetic energy stored in the field and armature (over-lapped or non-overlapped) windings of the motor. The application of the method to an experimental Japanese prototype gives good concordance with the experimental data.
Berechnung der Antriebskraft bei EDM-MAGLEV Beförderungssystemen mit supraleitenden Spulen
Übersicht Im Artikel wird ein analytisch-dreidimensionales Verfahren beschrieben, das die Berechnung der Antriebskraft erlaubt, die bei überschnellen Beförderungssystemen wie EDS-MAGLEV durch lineare Langstator-Synchronmotoren entsteht, wobei Supraleitungsspulen sowohl zur Motorerregung als auch zur magnetischen Levitation des Fahrzeuges verwendet werden. Das Verfahren berücksichtigt die endliche Spulendicke und geht aus von der Änderung der magnetischen Energie, die in den Anker- und Erregerwicklungen (Zylinder- sowie Wellenwicklungen) des Motors gespeichert ist. Die Werte der Antriebskraft, die durch die Anwendung dieses Verfahrens auf einen in Japan ausgeführten Experimentalprototyp ermittelt werden, weisen eine gute Übereinstimmung mit den experimentellen Werten auf.
  相似文献   
8.
Several experimental investigations in the past few years have highlighted the fact that the compressive strength of glass was significantly higher than its tensile strength, allowing new applications of glass in compression members. However, due to the high slenderness of structural glass elements made of thin glass panels, they tend to fail in a brittle manner. A substantial amount of fundamental research has been carried out in the past few years to investigate the stability behaviour of structural glass elements. However, although buckling of glass panels has been quite well studied, a very poor amount of research has been addressed to glass columns, which by contrast represent the most interesting case due to their direct application in buildings. In this paper, the results of ten compressive tests on glass panels and columns are presented and discussed. The main variables considered were slenderness of panels and the shape of the cross-section for columns. The results of six bending tests on monolithic and laminated glass panels are also shown, and the level of connection between the glass sheets was evaluated. A review of the theoretical background is provided and the results achievable with existing analytical models are compared.  相似文献   
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