Wyniki wyszukiwania - BazTech

1

Effect of WO3 on the morphology and photodegradation of dimethyl phthalate of TiO2 nanotube array photoelectrode

Xin Y., Wang G., Liu Y., Zang Z., Gao M.

Environment Protection Engineering

|

2018

|

Vol. 44, nr 3

129--139

EN

WO₃ modified TiO₂ nanotube array (WO₃/TNAs) photoelectrodes were fabricated via electrochemical deposition on TNAs/Ti photoelectrodes. The morphology and structure of WO₃/TNAs photoelectrodes were investigated by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The effects of deposition potential, deposition duration, NaWO₄ concentration, and calcination temperature on the morphology and the photocatalytic activity were investigated. The results showed that suitable amounts of WO₃ promoted the photocatalytic activity of TNAs photoelectrodes for the degradation of dimethyl phthalate (DMP). The optimal conditions for the fabrication of WO₃/TNAs photoelectrodes were as follows: deposition voltage 3.0 V, 10 min deposition duration, 0.01 mol/dm³ Na₂WO₄ concentration, 1.5 cm electrode gap, and 550 °C annealing temperature. The degradation rate of DMP reached 77% after 60 min of illumination by WO₃/TNAs photoelectrode. Additionally, WO₃/TNA photoelectrodes possessed superb stability for maintaining a high DMP degradation efficiency at more than 75% after 10 times of successive use with 60 min irradiation for each cycle. The enhancement of photocatalytic performance by the efficient combination of WO₃ with TNAs would provide a theoretical basis for the practical application of WO₃/TNA photoelectrodes in water treatment.

2

Effects of vinasse and silica mud on the performance of thermophilic fermentation of brewery sludge from brewery waste substrates

Xin Y., Shen J., Wang B., Zhu X., Wang Y., Wang G., Chen Q.

Environment Protection Engineering

|

2017

|

Vol. 43, nr 2

119--127

EN

The anaerobic digestion of mixing brewery sludge with vinasse and silica mud at various ratios under thermophilic conditions was explored. Vinasse, silica mud and beer sludge (the sludge from the treatment of beer wastewater) are the main solid wastes of the beer production. Uncontrolled decom-position of these wastes could cause large-scale contamination of soil, water, and air. The results of the investigation showed that the optimal ratio of beer sludge and vinasse was 1:1 under total solids of 10%, producing the highest amount of gas of 1.34 cm3/g within 24 h and 4.06 cm3/g in 10 days. The silica mud weakened the fermentation process and reduced the gas production, and the concentration of total organic carbon, total nitrogen and volatile solids decreased during the digestion. For the mixture of brewery sludge and vinasse, the content of the total organic matter in the biogas manure was more than 60% and the value of pH was 6.5 after the anaerobic digestion, indicating that the manure can be used as an organic fertilizer.

3

Spectral degrees of cross-polarization of stochastic anisotropic electromagnetic beams in modified non-Kolmogorov atmospheric turbulence

Chen F., Chen J., Zhao Q., Chen Y, Xin Y., Li J., Pan H.

Optica Applicata

|

2013

|

Vol. 43, nr 4

773--783

EN

Based on the extended Huygens–Fresnel principle, variations in generalized Stokes parameters of stochastic anisotropic electromagnetic beams propagating through modified non-Kolmogorov atmospheric turbulence have been analyzed. The changes in generalized Stokes parameters with different turbulence parameters and source parameters were analyzed first. After that, the distributions of the spectral degrees of cross-polarization (SDCP) of isotropic beams and anisotropic beams were simulated. The results show that the profiles of distribution of SDCP of these two kinds of beams are very different in the near field, and will fluctuate through the propagation in atmospheric turbulence, but at last, when the propagation distance is long enough, the difference in the source makes a slight difference in the final profiles of SDCP in the output plane. They mainly depended on the turbulence perturbation, and in the weak turbulence, the profiles of final distribution show more flatter features.

4

Generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation

Chen J, Xin Y, Chen Y, Chen F, Zhao Q

Optica Applicata

|

2013

|

Vol. 43, nr 2

s. 205--216

EN

The expressions for the elements of the on-axis and transverse generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation are presented and are used to study the polarization properties of the beams. Some typical numerical calculations of the on-axis and transverse Stokes parameters, polarization properties of the beams on propagation are illustrated. The results show that for different sources all the on-axis parameters are identical in the near field and keep fixed values in the far field. But the transverse parameters are affected greatly by the properties of the source even in the near field. We have also found that the spatial profiles of the transverse parameters remain unchanged upon propagation.

5

M-ary phase modulation for digital watermarking

Xin Y., Pawlak M.

International Journal of Applied Mathematics and Computer Science

|

2008

|

Vol. 18, no 1

93-104

EN

In spread spectrum based watermarking schemes, it is a challenging task to embed multiple bits of information into the host signal. M-ary modulation has been proposed as an effective approach to multibit watermarking. It has been proved that an M-ary modulation based watermarking system outperforms significantly a binary modulation based watermarking system. However, in the existing M-ary modulation based algorithms, the value of M is restricted to be less than 256, because as M increases, the computation workload for data extraction advances exponentially. In this paper, we propose an efficient M-ary modulation scheme, i.e., M-ary phase modulation, which reduces the computation in data extraction to a very low level. With this scheme, it is practical to implement an M-ary modulation based algorithm with a high value of M, e.g., M = 220. This is significant for a watermarking system, because it can either greatly increase the data capacity of a watermark given the necessary watermark robustness, or considerably improve the watermark robustness given the amount of information of the watermark. The superiority of the proposed scheme is verified by simulation results.