Radio-Frequency Characteristics of Partial Dielectric Removal HR-SOI and TR-SOI Substrates

High-resistivity silicon-on-insulator （HR-SOI） and trap-rich high-resistivity silicon-on-insulator （TR-S01） sub- strates have been widely adopted for high-performance rf integrated circuits. Radio-frequency loss and non- linearity characteristics are measured from coplanar waveguide （CPW） t lines fabricated on HR-SOI and TR-SOI substrates. The patterned insulator structure is introduced to reduce loss and non-linearity char- acteristics. A metal-oxide-semiconductor （MOS） CPW circuit model is established to expound the mechanism of reducing the parasitic surface conductance （PSC） effect by combining the semiconductor characteristic anal- ysis （pseudo-MOS and C-V test）. The rf performance of the CPW transmission lines under dc bias supply is also compared. The TR-SOI substrate with the patterned oxide structure sample has the minimum rf loss （〈0.2 dB/mm up to 10 GHz）, the best non-linearity performance, and reductions of 4 dB and 10 dB are compared with the state-of-the-art TR-SOI sample＇s, HD2 and HD3, respectively. It shows the potential application for integrating the two schemes to further suppress the PSC effect.

Characteristic of COD removal and sludge settleability in biological treatment of hypersaline wastewater

In order to investigate the feasibility of biological treatment of bypersaline wastewater produced from toilet flushing with seawater at low temperature, pilot-scale studies were established with plug-flow activated sludge process at low temperature （5-9℃） based on bench-scale experiments. The critical salinity concentration of 30 g/L, which resulted from the cooperation results of the non-halophilic bacteria and the halophilic bacteria, was drawn in bench-scale experiment. Pilot-scale studies showed that high COD removal efficiency, higher than 85 %, was obtained at low temperature when 30 percent seawater [ seawater/（seawater ＋ sewage） ] was introduced. The salinity improved the settleability of activated sludge, and average SV dropped down from 38% to 22. 5% after adding seawater. Sludge bulking could be forborne effectively because filamentous bacteria couldn＇t subsist under high salinity concentration.

An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen（C/N） ratio.A common solution is to add external carbon sources,but amount of liquid is difficult to determine.Therefore,a combined wood-chip-framework substrate（with wood,slag and gravel） as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem.Results show that the removal rate of ammonia nitrogen（NH_4~＋-N）,total nitrogen（TN） and chemical oxygen demand（COD） could reach 37.5%-85%,57.4%-86%,32.4%-78%,respectively,indicating the combined substrate could diffuse sufficient oxygen for the nitrification process（slag and gravel zone） and provide carbon source for denitrification process（wood-chip zone）.The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip,respectively.Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process,while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process.This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.