Different amounts of Mn and Ce oxides were loaded onto nitric acid-modified activated carbon (ACN) by wet impregnation. The series of catalysts were employed for the selective catalytic reduction of NOx by NH3 at temperatures between 100 and 250 °C. Cerium-modified catalysts exhibited higher de-NOx performance than those modified with Mn/ACN, even with the same total loadings. The precursor solution with a molar ratio for Ce/(Mn + Ce) of 0.4 exhibited the highest catalytic activity. Enhanced resistance to SO2 and H2O and better stability were observed for 10%Mn–Ce(0.4)/ACN relative to 10%Mn/ACN. The catalysts were further characterized by N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed desorption of ammonia (NH3-TPD). The N2 physisorption and XRD results suggested that co-doping Ce with Mn increased the surface area and promoted the dispersion of Mn–Ce binary metal oxides. H2-TPR the NH3-TPD results demonstrated that the interaction between manganese oxide and cerium oxide species enhanced the redox and surface acidity of 10%Mn–Ce(0.4)/ACN. 相似文献
A high performance hybrid ion capacitors has been developed by using B, N dual-doped 3D superstructure carbon cathode and prelithiated graphite anode. 相似文献
Functional polypropylene (PP) is prepared by graft poly(AMS-co-DMAEMA) onto PP chains through melt blending, and then microporous membranes of functional PP are made by casting and stretching, and finally the polycation microporous membranes are obtained via quaternization. The obtained microporous membranes show good hydrophilicity and antibacterial properties. 相似文献
One new 4-chromanone glycoside, 5-O-β-d-glucopyranoside-4-chromanone (1), together with 21 known polyphenols, was isolated from the leaves of Malus hupehensis. Their structures were elucidated on the basis of extensive spectroscopic methods including NMR (1D and 2D), mass (ESIMS and HRESIMS), IR, and by comparison with the data reported in the literature. Some of the isolated compounds were screened for antioxidant activity. Compounds 18 and 14 exhibited significant antioxidant activities with SC50 values 2.73 and 2.91 μg/mL, respectively, while 17, 19, 11, 7, 20, 22, 12 and 13 exhibited moderate activities with SC50 values ranging from 5.24–11.86 μg/mL. The HPLC fingerprint profiles of the leaves and fruits extracts were also analysed, which showed that the constituents were almost the same in both the extracts except for the content of phlorizin which was present in higher amount in the leaves. 相似文献
We perform an experimental study on high-order harmonic generation (HHG) of aligned acetylene molecules induced by a 35-fs 800-nm strong laser field, by using a home-built HHG spectrometer. It is observed that the molecular HHG probability declines with increasing the laser ellipticity, which is in consistence with the deduction from the well-known tunneling-plus-rescattering scenario. By introducing a weak femtosecond laser pulse to nonadiabatically align the molecules, we investigated the molecular orbital effect on the HHG in both linearly and elliptically polarized driving laser fields. The results show that the harmonic intensity is maximum for the molecular axis aligned perpendicularly to the laser electric field. It indicates that both the highest occupied molecular orbitals (HOMO) and HOMO-1 contribute to the strong-field HHG of acetylene molecules. Our study should pave the way for understanding the interaction of molecules with ultrafast strong laser fields. 相似文献
Medicines or drugs have unique characteristics of short life cycle, small size, light weight, restrictive distribution time and the need of temperature and humidity control (selected items only). Thus, logistics companies often use different types of vehicles with different carrying capacities, and considering fixed and variable costs in service delivery, which make the vehicle assignment and route optimization more complicated. In this study, we formulate the problem to a multi-type vehicle assignment and mixed integer programming route optimization model with fixed fleet size under the constraints of distribution time and carrying capacity. Given non-deterministic polynomial hard and optimal algorithm can only be used to solve small-size problem, a hybrid particle swarm intelligence (PSI) heuristic approach, which adopts the crossover and mutation operators from genetic algorithm and 2-opt local search strategy, is proposed to solve the problem. We also adapt a principle based on cost network and Dijkstra’s algorithm for vehicle scheduling to balance the distribution time limit and the high loading rate. We verify the relative performance of the proposed method against several known optimal or heuristic solutions using a standard data set for heterogeneous fleet vehicle routing problem. Additionally, we compare the relative performance of our proposed Hybrid PSI algorithm with two intelligent-based algorithms, Hybrid Population Heuristic algorithm and Improved Genetic Algorithm, using a real-world data set to illustrate the practical and validity of the model and algorithm.
Succinct expressions for the matrix elements of various vibrational operators have been derived in the basis of the nondegenerate
harmonic oscillator. Among these are the matrix elements of
and
, which are found to be dependent upon two quantities and their derivatives. Furthermore, the derivative property of the commutator
is used to obtain an explicit expression for the derivatives of an operator in terms of its nested commutator with the conjugate
momentum. It may be applied to any of the above cases to obtain the matrix representatives of expressions such as the mixed
products
, for example. In addition, a simple expression for 1/q is given and its derivatives may be evaluated by this commutator technique. Also the matrix elements of a Gaussian-type operator
has been evaluated.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
We demonstrate an apparatus for measuring time-dependent x-ray diffraction. X-ray pulses from a synchrotron are diffracted by a pair of Si(111) crystals and detected with an x-ray streak camera that has single-shot resolution of better than 1 ps. The streak camera is driven by a photoconductive switch, which is triggered by 100-fs laser pulses at a repetition rate of 1 kHz. The laser and the streak camera are synchronized with the synchrotron pulses. In the averaging mode, trigger jitter results in 2-ps temporal resolution. We measured the duration of 5-keV pulses from the Advanced Light Source synchrotron to be 70ps. 相似文献
In recent years, there has been considerable interest in organotin(Ⅳ) compounds. One of the important reasons is that many organotin compounds are biologically active1-3. The diorganotin(Ⅳ) complex containing carboxylate ligand have been investigated fo… 相似文献