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排序方式: 共有93条查询结果,搜索用时 15 毫秒
1.
HY zeolites catalyze the crossed aldol condensation of acetophenone with benzaldehyde, in benzene at 80 °C, to give trans- and cis-chalcones. Together with these expected products, 3,3-diphenylpropiophenone is also produced. In the analogous basic condensation, using phase transfer catalysis, the Michael adduct was not detected, and besides chalcone a small percentage of the Cannizzaro reaction product was observed. 相似文献
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Massi Gionata Morganti Gianluca Claudi Andrea Zingaretti Primo Mancini Adriano Frontoni Emanuele 《Microsystem Technologies》2018,24(3):1401-1411
Microsystem Technologies - Highly accelerated life test (HALT) is a test methodology to evaluate reliability of mechanical and electromechanical devices. HALT is often used on devices that must be... 相似文献
4.
Ana Petkovšek Matej Maček Primož Pavšič Feri Bohar 《Bulletin of Engineering Geology and the Environment》2010,69(4):561-574
In road construction the general term fines is used to describe particles passing the 0.063, 0.074 or 0.08 mm sieve. Some
types of fines are considered to be relatively inert and have almost no effect on pavement performance, whilst the presence
of even small amounts of others can significantly affect the stiffness and freezing–thawing behaviour of unbound and hydraulically
bound layers. This paper presents the results of research on 12 Slovenian aggregates produced from limestone and dolomite
bedrock, and naturally occurring river alluvium gravel. At each production site three different materials were sampled and
tested: the actual aggregate for unbound base layers, the clayey soils, which presented the most potentially harmful component
at the specific location, and the stony dust, which presented the finest size of crushed aggregate and is typically found
as coatings on the crushed grains. Six different methods were used to identify the nature of the fines: X-ray diffractometry,
carbonate content determination, methylene blue, sand equivalent, Enslin–Neff water absorption, Atterberg limits test, soil
suction measurements and soil water characteristic curves. Based on the results, the relationship between the properties of
the different fines was determined and included in draft Slovenian national criteria for sand equivalent and methylene blue
values currently being trialed. 相似文献
5.
A Hybrid modeling approach, combining an analytical model with a radial basis function neural network is introduced in this paper. The modeling procedure is combined with genetic algorithm based feature selection designed to select informative variables from the set of available measurements. By only using informative inputs, the model's generalization ability can be enhanced. The approach proposed is applied to modeling of the liquid–phase methanol synthesis. It is shown that a hybrid modeling approach exploiting available a priori knowledge and experimental data can considerably outperform a purely analytical approach. 相似文献
6.
John Fredy Vélez Santa Svit Menart Marjan Bele Francisco Ruiz-Zepeda Primož Jovanovič Vasko Jovanovski Martin Šala Milutin Smiljanić Nejc Hodnik 《International Journal of Hydrogen Energy》2021,46(49):25039-25049
Developing a Pt-based electrocatalytic material able to selectively catalyze hydrogen oxidation (HOR) while supressing oxygen reduction (ORR) is beneficial for durability of the fuel cells. Namely, degradation of carbon supported Pt particles is dramatically influenced by the unwanted ORR enrolling at the anode due to the air penetration during start-up/shut-down events. We present an organic matrix tris(aza)pentacene (TAP), which belongs to π-functional materials with ladder-like conjugated nitrogen-containing units, as the support for Pt to form a “smart” fuel cell anode able to selectively catalyze HOR and to suppress ORR. “Switching-on/off” of the composite material activity is provided by reversible reduction/oxidation of the TAP in the low potential region which provokes TAP - HxTAP transition. Conductivity of the reduced HxTAP enables supported Pt particles to effectively run HOR. In contrast, restricted conductivity of oxidized TAP analogue leads to the substantial drop in the ORR activity with respect to benchmark Pt/C catalyst. 相似文献
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Tadej Rojac Marija Kosec Maria Połomska Bożena Hilczer Primož Šegedin Andreja Bencan 《Journal of the European Ceramic Society》2009,29(14):2999-3006
We studied the mechanochemical synthesis of KNbO3, starting from a powder mixture of K2CO3 and Nb2O5. The milling experiments were designed with different ball-impact energies in order to investigate the mechanochemical reactions. X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, Raman spectroscopy and transmission electron microscopy were used to characterize the samples. Based on the results, we propose a mechanism for the mechanochemical reaction between K2CO3 and Nb2O5. The first stage of the reaction is characterized by the formation of an amorphous carbonato complex, which decomposes after prolonged milling at higher ball-impact energy giving rise to the crystallization of KNbO3 and other niobate phases with a molar ratio K/Nb < 1. The reaction course is discussed and compared with the Na2CO3–Nb2O5 system. 相似文献
8.
Frontoni Emanuele Mancini Adriano Zingaretti Primo Contigiani Marco Bello Luigi Di Placidi Valerio 《Microsystem Technologies》2018,24(3):1369-1377
Microsystem Technologies - The shelf out-of-stock (SOOS) problem is relevant for retailers and producers since the absence of products on the shelf can lead to a significant reduction of... 相似文献
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BACKGROUND: Indocyanine green (ICG) is a sterile, water-soluble, tricarbocyanine dye that can be used in fundus angiography as an adjunct to sodium fluorescein. It has a peak spectral absorption of 805 nm in blood plasma or blood, as compared with fluorescein, which has a peak spectral absorption of 465 nm. Because the absorption and emission of ICG lies around 835 nm, transmission of energy by the retinal pigment epithelium (RPE) and serosanguinated material is more efficient in this region than in the region of visible light energy. ICG has the property of being approximately 98% bound to blood protein, disallowing extravasation of excessive dye in the highly fenestrated choroidal vasculature. METHODS: The characteristics of ICG are discussed, including administration and dosage, adverse reactions and use of infrared filters for fundus photography. In addition, two cases are presented to illustrate the clinical application of ICG for diagnosis and treatment of choroidal neovascular membranes. RESULTS: ICG videoangiography can be used to reveal subfoveal choroidal neovascular membranes not previously identified with fluorescein; angiograms can also be used to dramatically highlight retinal and choroidal changes. CONCLUSIONS: The use of ICG for fundus videoangiography provides a more accurate and complete evaluation in certain cases of subretinal and choroidal disease. 相似文献
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