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An efficient conversion of cellulose to CH 4 over porous Ni catalyst under hydrothermal conditions has been investigated. The results indicated that porous Ni catalyst showed significant catalytic activity and selectivity for the cellulose conversion to methane. Porous Ni catalyst still remained good activity with gaseous hydrogen after three runs for the transformation. The maximum CH 4 yield of 73.8% from cellulose was achieved in the presence of Zn as a reductant over porous Ni at 325 °C for 2 h. This value obtained is the highest yield for the formation of CH 4 from cellulose to date. The mechanistic studies for this transformation proposed three possible pathways for the formation of CH 4 from cellulose: (1) pyrolysis, (2) hydrogenation of intermediates, and (3) methanation. The present work provides an environmentally benign and efficient route for the conversion of cellulose to CH 4 with high efficiency and high selectivity and has great significance for both academia and industry.

We investigate the guided modes in monolayer graphene-based waveguides with asymmetric quantum well structure induced by unequal dc voltages. The dispersion relation for the guided modes is obtained analytically, the structures of the guided modes are discussed under three distinct cases. For the cases of the classical motion and the Klein tunneling, the asymmetric structure does not influence the mode structures dramatically compared with that in the symmetric waveguide. But for the mixing case of the former two, the mode structures and the motion characteristics for the electron and the hole exhibit different behaviors at same condition. The results may be helpful for the practical application of graphene-based quantum devices.

Single phases of TbxY1-x Al3(BO3)4（0≤x≤0.2）phosphors were synthesized by a sol-gel combustion method with citric acid as fuel and complexing agent. Our method involves only exothermic decomposition of an aqueous citrate–nitrate gel and the gel yielded nanocrystalline TbxY1-x Al3(BO3)4 phosphors at 1000°C, without any formation of intermediate phase. The optimal doping concentration of Tb3+ ions in the serials was found to be approximately 12mol%. The decomposition of the gel was investigated by TG–DTA. The product has been further characterized by X-ray powder diffractometry (XRD) and fluorescent divide spectroscopy (FDS).

The absorption factor of the wafer is defined as the fraction of incident electromagnetic irradiance that is absorbed by the wafer.The absorption factor is derived from refractive index and the extinction coefficient of the wafer theoretically.Based on our analysis ,the absorption efficiency of the muti-layer configuration will be higher than the individual one at the same condition.

The mechanically induced self-propagating reaction (MSR) and hot-pressing consolidation were adapted to synthesize Ti2AlC and Ti3AlC2 using Ti, C and Al powder mixtures. The effects of Al content on the microstructure and mechanical properties of fully dense Ti2AlC and Ti3AlC2 were investigated. The results reveal that the Ti3AlC2, TiC and TiAlx transitional phases were formed by mechanically alloying according to the mechanically induced self-propagating reactions (MSR). Through hot pressing the as-milled powders with initial composition of 2Ti/1.5Al/C and 2Ti/Al/C, respectively, at 1100°C for 1 h, the desired high purity Ti2AlC and Ti3AlC2 were produced. SEM images confirmed that the as-fabricated Ti2AlC and Ti3AlC2 grains are plate-like with nanoscale layered structure and dispersed uniformly.

A new photo-Fenton-like catalyst with high activity, Fe2V4O13, has been found. It can be obtained by a simple wet chemical process. The catalyst has a nano-lamellar structure with a thinness of less than 100 nm, a BET surface of 52.26 m2 g−1, and a band-gap of 1.59 eV favorable to absorption of visible light. Experiments demonstrated that Fe2V4O13 could effectively catalyze degradation of Acid Orange II (AOII) by H2O2 in visible light. The degradation was well fitted by a simple pseudo-first-order reaction with a rate constant of 0.0965 min−1. Moreover, the photo-Fenton-like catalytic activity of Fe2V4O13 was much higher than that of not only α-Fe2O3 and V2O5 but also their mixture (Fe2O3 + 2V2O5) with an identical atomic ratio of Fe and V, and that of both Fe3O4 and γ-FeOOH. The high catalytic activity of Fe2V4O13 possibly involves a special two-way Fenton-like, semiconductor photo-catalytic mechanism and the synergistic activation of Fe(III) and V(V) in Fe2V4O13 towards H2O2.

Based on the laser technique, a method of detecting liquid surface tension was proposed. The relation between the laser diffraction pattern and liquid surface tension is derived. In this experiment, laser diffraction patterns from liquid surface waves were collected .The experiment results show that the proposed way is feasible.

A method has been forward to measure the samll vibration based on Michelson Interferometer, and the Doppler Effect is under consideration.The information about vibration can be detected by the photo detector and display on the digital oscilloscope at the same time.

In the present paper, the theoretical analysis was performed of the phenomenon and causes of the spectral line missing stage in diffraction of grating and crystal X-ray diffraction, and their application was discussed. It was concluded that the crystal X-ray diffraction probably lies in the fact that the geometrical structure factor of unit cells of some crystal materials is zero, and secondly, the spectral line missing stage in diffraction could be an interesting subject in the crystal X-ray diffraction research. On the whole, these conclusions may provide an important reference to the study on material phase, structure and intact analysis etc.

Several reasons for atomic spectral line broadening in terms of theory are given, that's: natural broadening: Doppler broadening; collision broadening, respectively. Some estimated data based on these reasons are provided, which may be of significance for atomic spectral measurements, and the data are in agreement with experiments.