Ping Zhai

Survey of Rural Domestic Sewage Treatment Systems of Songjiang District in Shanghai, China

Due to the relatively unprogressive economic and social development of Songjiang rural areas of Shanghai city in China, the degree of rural domestic sewage treatment was relatively weak and hysteretic. The rural sewage treatment systems of Songjiang district were investigated through field survey. Finally, the systems of soil infiltration-constructed wetland and combinatorial biofilter, with obvious advantages, were proposed to popularize in Songjiang rural areas more suitably.

Multiwall Carbon Nanotubes-Modified Glassy Carbon Electrode for Square-Wave Stripping Voltammetric Determination of Aqueous Antimony (III) Ion

A glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNTs) for electrochemical square-wave stripping voltammetric (SWV) determination of antimony (III) was introduced. Various experimental parameters, such as the amounts of carbon nanotubes, the deposition potential and time, the electrolyte solution, etc, were thoroughly optimized and discussed. Under the optimum experimental conditions, the MWCNTs-modified GCE exhibited well linear behaviour in the antimony(III) concentration range from 0.04 to 0.26 mg/L (R=0.9983) with a detection limit of 3.20×10-4 mg/L (S/N=3) under a 360 s accumulation. The proposed electrode also exhibited encouraging properties for measurements of simulated water samples.

Effect of Curing Temperature on the Properties of Quartz Fiber Felt Reinforced Fused Silica Densified with Simethicone

In this paper, the needle-punched quartz fiber reinforced fused silica composite was densified by impregnating simethicone in vacuum and then solidified at different temperatures. The volume density and mechanical properties were investigated by means of Archimedes method and three point bending method, while the micro-structure was tested by SEM. The results showed that the volume density of composite increased from the non-impregnation of 1.457 g/cm3 up to the maximum of 1.718 g/cm3. The compressive strength increased at higher temperatures, up to 84.4 MPa at 500 °C. The tensile strength was weaker with the increase of the temperature, while the bending strength first increased then reduced, and reached the maximum of 43.2 MPa at 160 °C with an increase of 41.64%.

Characterization of SiO2 Aerogel/SiO2 Fiber Composites Prepared by Sol-Gel Method

Quartz fiber composites filled with nanosized SiO2 were prepared by sol-gel method with vacuum impregnation , supercritical drying and surface modification. The silica sol for vacuum impregnated were made from tetraethyl orthosilicate (TEOS), anhydrous ethanol, water and acid catalyst as the starting materials. The water adsorption rate, apparent porosity and electrical properties of composites were investigated by means of archimedes method and waveguide method while the surface area and pore size of the aerogel samples were tested by BET, the mechanism of hydrophobicity was also discussed. The results showed that the moisture absorption rate of products was decreased to 1.21% from 17.36% that without filled with nanosized SiO2, with a decreasing range of 93%. Additional coating could make the rate even as low as 0.052%.The dielectric constant had no significant change while the loss tangent decreased from 3.1╳10-3 to 1.4╳10-3,with a decreasing range of 51.2%.

Carbon Fiber Reinforced Phosphate Porous Ceramic Composites

Fiber porous ceramics are the excellent candidates for a variety of applications, and thus, their research is a hotspot in recent years. In this study, carbon fiber reinforced phosphate porous ceramics composites were prepared by acupuncture and in-situ solidification vacuum-assisted liquid-phase infiltration method. The tensile strength of composite was tested by universal testing machine, the microstructures of the specimen were observed by scanning electron microscopy while the thermal analysis was detected by Thermo Gravimetric Analyzer. The results show that the carbon fiber reinforced phosphate porous ceramics composites which is prepared by the technology showed above have a pore rate of 63.7%.The tensile strength reached 50.2MPa with an average pore size of at most 50μm.It also has good thermal shock resistance.

Preparation and Characterization of β-Eucryptite Glass Ceramics

In this paper, β-eucryptite glass ceramics were synthesized by using solid reaction method. Phase constitution, structure and properties of the material were studied by X-ray diffraction (XRD) and differential thermal analysis (DTA). Furthermore, the effects of heat treatment temperature and preservation time on the thermal expansion coefficient were also analyzed. The results showed that the crystallization temperature of β-eucryptite glass ceramics was in the range of 810-860 °C and the content was more than 90%. With the increase of heat treatment temperature, the material expansion coefficient decreased.

Porous Silicon Nitride Microwave Transparent Material with Compounded Component Pore Former

It is an effective way to decrease dielectric constant of microwave transparent materials by improving porosity rate. Network -Si3N4 porous transparent materials were prepared by gas pressure sintering (GPS) with Y2O3 additions. Porosity rate of silicon nitride using pore former with different content starch, polytetrafluoroethylene (PTEE) powder respectively and their compounded component were discussed in this paper. It is concluded that porosity rate can be improved by all the three, starch is most favorable to improve porosity but great volume rebound after cold iso-static pressing were happened and easily lead to crack of green body. Method of pore-making by step on principle of pore formers discharging in different temperature range used to get high strength and porosity green body. Series of porous silicon nitride microwave transparent materials were prepared with porosity rate from 48% to 67%, bending strength from 162MPa to 59MPa and dielectric constant from 3.41 to 2.37.