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Xian-Long Zhang Shuang-Shuang Lv Cui-Ping Zhang Xue-Ping Wu Lian-Feng Zhang Jun-Wei Wang Xiao-Bin Jia Heng-Jian Zhang 《Chemical Papers》2015,69(12):1548-1555
Palygorskite (PG)-supported manganese oxide catalysts (MnOx/PG) were prepared for the selective catalytic reduction (SCR) of NO with ammonia in the presence of SO2 at low temperature. The influence of gaseous SO2 on the performance of the catalyst was studied by means of specific surface area (Brunauer-Emmett-Teller, BET) analysis, scanning electron microscopy (SEM), thermogravimetric (TG) analysis, temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). The results showed that the SCR activity of Mn10/PG was significantly inhibited by gaseous SO2 at temperatures below 300°C. However, the SCR activity of Mn10/PG was markedly promoted by SO2 in a higher temperature range of 300°C to 500°C. The sulphating of surface active species (MnOx) was suggested to inhibit the oxidation of NH3 to NO leading to enhancement of the SCR activity at a higher temperature range of 300°C to 500°C and decrease in the SCR activity at temperatures below 300°C. 相似文献
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Routing is one of the important steps in very/ultra large-scale integration (VLSI/ULSI) physical design. Rectilinear Steiner minimal tree (RSMT) construction is an essential part of routing. Macro cells, IP blocks, and pre-routed nets are often regarded as obstacles in the routing phase. Obstacle-avoiding RSMT (OARSMT) algorithms are useful for practical routing applications. However, OARSMT algorithms for multi-terminal net routing still cannot meet the requirements of practical applications. This paper focuses on the OARSMT problem and gives a solution to full-scale nets based on two algorithms, namely An-OARSMan and FORSTer. (1) Based on ant colony optimization (ACO), An-OARSMan can be used for common scale nets with less than 100 terminals in a circuit. An heuristic, greedy obstacle penalty distance (OP-distance), is used in the algorithm and performed on the track graph. (2) FORSTer is a three-step heuristic used for large-scale nets with more than 100 terminals in a circuit. In Step 1, it first partitions all terminals into some subsets in the presence of obstacles. In Step 2, it then connects terminals in each connected graph with one or more trees, respectively. In Step 3, it finally connects the forest consisting of trees constructed in Step 2 into a complete Steiner tree spanning all terminals while avoiding all obstacles. (3) These two graph-based algorithms have been implemented and tested on different kinds of cases. Experimental results show that An-OARSMan can handle both convex and concave polygon obstacles with short wire length. It achieves the optimal solution in the cases with no more than seven terminals. The experimental results also show that FORSTer has short running time, which is suitable for routing large-scale nets among obstacles, even for routing a net with one thousand terminals in the presence of 100 rectangular obstacles. 相似文献
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Adsorption of hydrogen molecules on an Ni-doped (8,0) single-walled
carbon nanotube (SWNT) is investigated by using first-principles
density functional calculations. The result shows that a single
Ni atom adsorbed on the bridge site of the tube could cannot
dissociate the H2, however it can chemisorb three H2 at
most, with the average binding energy per H2 suitable
for the hydrogen storage at the room temperature. More H2 would
physisorb around an Ni atom weakly. As for the SWNT with an Ni dimer
adsorbed, we find that when the H2 approaches the Ni--Ni bond,
it dissociates without overcoming any barrier and makes bonds
with Ni atom. 相似文献
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Cheng XL Ma SC Wei F Wang GL Xiao XY Lin RC 《Chemical & pharmaceutical bulletin》2007,55(9):1390-1392
A new sesquiterpene, neolindenenonelactone (1), was first isolated from the dried roots of Lindera aggregata (SIMS) KOSTERM., along with four known compounds, linderane (2), isolinderalactone (3), linderalactone (4), and 8-hydroxylindestenolide (5). Their chemical structures were elucidated using spectral analysis of fast atom bombardment mass spectroscopy, one-dimensional nuclear magnetic resonance spectroscopy and two-dimensional-nuclear magnetic resonance spectroscopy including (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer, heteronuclear multiple-bond coherence, and single-crystal X-ray diffraction techniques. 相似文献
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WJ Li ZH Zhang XL Cheng J Liu Y He C Zhou Y Guo RC Lin GL Wang 《Molecules (Basel, Switzerland)》2012,17(8):8773-8781
Two new compounds, (2S,3R)-methyl 7-hydroxy-2-(4-hydroxy-3-methoxy-phenyl)-3-(hydroxymethyl)-2,3-dihydrobenzofuran-5-carboxylate (1) and (4R,5S)-5-(3-hydroxy-2,6-dimethylphenyl)-4-isopropyldihydrofuran-2-one (2), tentatively named norcurlignan and limlactone, respectively, were isolated from Liriope muscari, together with the known compound (-)-pinoresinol (3). The structures of these compounds were elucidated and characterized on the basis of 1D NMR, 2D NMR, CD and MS data. The in vitro antioxidant activities of compounds 1-3 were assessed by the DPPH and ABTS scavenging methods. 相似文献
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