Chenbo Ma,Jinjun Zhang,Kai Feng,Zixin Li,Chaohui Chen,Qian Huang,Yingda Lu
Electrical treatment is emerging as an efficient approach to improve the cold flowability of crude oils. In this work, waxy model oils under static state were electrically treated by an in-house apparatus. The influence of asphaltenes, the most aromatic of the heaviest components of crude oil, on the performance of electrical treatment was systematically examined for the first time. The presence of asphaltenes was found to significantly undermine the effectiveness of electrical treatment on waxy oils, and this negative influence became more pronounced at higher asphaltene contents. The effect of asphaltenes was largely independent on their aggregation state. Interestingly, although asphaltenes generally have a negative effect on electrical treatment of waxy oils, increasing polarity of asphaltenes alleviates this unfavorable effect. The results from microscopic analysis suggest that the less pronounced change in the size distribution of wax crystals might be one of the reasons for the unfavorable effects of asphaltenes on electrical treatment of waxy oils.
Low temperature stability has limited the applications at elevated temperature for ABO 3 -type lead-free ceramics. And multi-grade resonances of piezoelectric ceramics are hardly obtained although the resonances are very important in some applications such as filter and resonator . High piezoelectric properties and large mechanical quality factors with multi-grade resonances can be obtained in (Li + -La 3+ ) co-doped BaTiO 3 ceramics, and excellent temperature stabilities are achieved in the ceramics. It has been shown that the thermal treatments both with and without electric field at 200 °C improve the piezoelectric properties and thermal stability further. Large piezoelectric constant (272 pC N 1 ) and huge mechanical quality factor (2010) was obtained after thermal-electrical treatment, which is caused by Li + -La 3+ ionic pair aligning along the external electric filed during thermal-electrical treatment. Moreover, the present study provides an effective method to design combination properties with high temperature stability for ABO 3 perovskite ferroelectric ceramics .
In this paper, electret treatment was used to enhance the electrostatic repulsion between the membrane and bovine serum albumin, so as to improve the anti-fouling ability and recycling rate of the membrane. The polarization charge is provided by the dipole orientation of polyvinylidene fluoride (PVDF) materials, and the space charge is composed of the interfacial charge between the filler and the matrix and the bulk charge of the hollow structure of the multi-walled carbon nanotubes. The results showed that after electret treatment, the surface potential of the membrane increased, the PVDF crystal type changed from α to β, and the crystallinity increased. Grafting of N -vinylpyrrolidone onto multi-walled carbon nanotubes (MWCNTs-g-PVP), which contain a large number of hydrophilic groups after modification, reduces the contact angle of the composite film from 86.9° to 62.7°. The pure water flux and flux recovery rate of MWCNTs-g-PVP/PVDF composite membranes after electret treatment was increased from 189.31 L·m −2 ·h −1 and 90% to 233.55 L·m −2 ·h −1 and 94.7%, respectively, and the rejection rate increased about 30%. Through the circulation experiment, it can be seen that the anti-fouling performance and recycling rate of the membrane is improved, which is caused by electrostatic repulsion.
The altered morphology, amylose content, microstructure, viscosity and thermal properties of potato starch after heating by radio frequency (RF) and microwaves (MW) were studied and contrasted with the native potato starch. The results showed that the MW treatment roughens the starch surface and lowers the amylose content of the starch, even more than the RF-treated starch does. The starch granule size of MW treated was larger than RF treated. RF treatment altered the structure and reduced the crystallinity of the starch, but the MW treatment did not affect the crystal form. The gelatinization temperature of the MW-treated starch was higher than the native potato starch, while the RF-treated starch was lower than the native starch. The results also indicated that the peak viscosity and the breakdown viscosity values of the RF-treated starch consistently surpassed that of the MW-treated starch. The results exposed the facts that RF treated starch showed the same trend on crystal and pasting properties compared with the hot water annealing starches, which suggested RF can be an efficient method for starch annealing.
危险品化学品经营许可证（带存储）