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排序方式: 共有866条查询结果,搜索用时 15 毫秒
71.
Muhammad U. Farooq Xiangxue Zhang Yanan Guan Wenyao Chen Jinghong Zhou Jing Zhang Gang Qian Xuezhi Duan Xinggui Zhou Weikang Yuan 《American Institute of Chemical Engineers》2023,69(1):e17932
Methyl methacrylate (MMA) is an important monomer for the production of acrylic plastics and polymer dispersions. In this study, we demonstrate a strategy to synergize the electronic and geometric effects of the Au/CeO2 catalyst, achieving three orders of magnitude improvement in reaction rate for the oxidative esterification of methacrolein to MMA. The electronic properties of Au in terms of the valence electron population of 5d states are decoupled from the redox ability and acid–base properties of catalyst support as the main cause for the significant increase in the specific activity of the active site. Moreover, the Au edge site is identified as the main active site for this reaction, whose number reaches the maximum for the 1.6 nm-sized Au particles. Hence, the synergism between the electronic (lower valence electron population of 5d states) and geometric (more edge active sites) promotions of the Au-10/CeO2 catalyst contributes to the highest catalytic activity. 相似文献
72.
Effects of Guar–Xanthan Gum Mixture as Fat Replacer on the Physicochemical Properties and Oxidative Stability of Goshtaba,a Traditional Indian Meat Product 下载免费PDF全文
73.
Farooq A. Khanday Costas Psychalinos Nisar A. Shah 《Circuits, Systems, and Signal Processing》2013,32(3):959-978
Square-root-domain (SRD) CMOS analog realization of a single cell architecture of the complex Temporal Derivative Cellular Neural Networks (TDCNNs) is introduced in this paper. TDCNN initiates time derivative ‘diffusion’ between CNN cells for non-separable spatiotemporal filtering applications, where the input to the CNN is an image that changes over time. The evaluation of the performance of the complex SRD TDCNN cell has been done using the Cadence Orcad software with TSMC 0.18-μm CMOS process model parameters. The provided simulated results confirm the validity of the theory. 相似文献
74.
Shazia Bashir M. Shahid Rafique Wolfgang Husinsky Alison Hobro Bernhard Lendl 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(23-24):3606-3610
The phenomenon of nanohillock-like defect formation on the surfaces of CR-39 by ultra-short laser irradiation is investigated using an Atomic Force Microscope (AFM) and Raman Scattering. A polymer CR-39 target was exposed to Ti:sapphire 25-fs laser pulses with a central wavelength at 800 nm. Samples were irradiated for different laser fluences both in air and vacuum. Detailed surface topographical features of the bombarded samples were characterized by atomic force microscopy in contact mode in air at room temperature. AFM reveals that the growth of nanohillocks and their features are strongly dependent on the ambient condition, target position from focus, and irradiation fluence. The appearance of these nanohillocks in the range 1–20 nm in height and 10–90 nm in diameter are regarded as typical features for fast electronic processes (correlated with existence of hot electrons) and are explained on the basis of Coulomb explosion. These nanostructures due to localization of laser energy deposition in small areas provide a possible pathway from dense electronic excitation to atomic motion causing permanent structural modification which are well correlated to structural alterations, like crosslinking and chain scissions, inferred from Raman spectroscopy. 相似文献
75.
UVB irradiation alters cellular responses to cytokines: role in extracellular matrix gene expression
VP Werth KJ Williams EA Fisher M Bashir J Rosenbloom X Shi 《Canadian Metallurgical Quarterly》1997,108(3):290-294
Chronic myeloid leukemia course was evaluated versus sex in 271 patients. Chronic stage involved more pronounced leukocytosis, thrombocytosis and splenomegaly in females, the latter showing higher susceptibility to anemia. As a result, treatment has to deal with a greater mass of tumor. A relatively longer survival time in males (44 and 42 months, respectively) suggest a higher effectiveness of therapy in such patients. When diagnosed, leukocytosis, thrombocytosis, enhanced splenomegaly and anemia should be regarded as factors of unfavorable prognosis. 相似文献
76.
Thin films of cobalt(II) oxyhydroxide on platinum have been prepared by electrodeposition. The chemical diffusion coefficient D of the hydroxide ion through the material has a marked temperature dependence, showing a simple activated behaviour in the range 273–292 K. The activation energy to ionic movement was rather large at 54.5 kJ mol–1 which, it is proposed, is ascribable to ion hopping. When spins have changed alignment, at the Néel transition temperature T
Nr
the activation energy more than doubled to 125 kJ mol–1; and the diffusion coefficients obtained above this temperature also increased dramatically. It is proposed that structural changes occur in the electrodeposited oxide at about T
Nr
hence the change in activation energy. 相似文献
77.
78.
The objective of this study was to formulate and develop a good quality cottage cheese dressing using acid whey as the main ingredient. Up to 72% of cottage cheese whey was used in the dressing mixes. The percentage of fat (4.10–5.05%) and total solids (19.41–20.24%) approached the desired level and was within the legal limits for regular cottage cheese. Sensory evaluation scores for flavour, body/texture and appearance were not adversely affected by the use of acid whey. The sensory evaluation scores for all four products made with whey- or skimmed milk-based dressings were higher than the commercial control. 相似文献
79.
80.