控制排气放空噪声的消声器之研究与应用

排气放空噪声是工业上常遇到的噪声源。本文介绍了根据喷注噪声发射理论研制成的小孔喷注与节流降压相复合的新型消声器，适用于高压气源排放，取得了较好的消声效果。鉴于喷注发射噪声的强度取决于喷注的驻压与喷口直径等参量，对节流降压层的设计与控制小孔喷注层的驻压大小，提出了新的见解，可供设计研究喷注消声器参考使用。     

Modeling the effects of concentration history on the slow desorption of trichloroethene from a soil at 100% relative humidity

To determine the effects of concentration history on slow sorption processes, desorption kinetic profiles for trichloroethene (TCE) were measured for a soil at 100% relative humidity subject to different exposure concentrations and exposure times. Exposure concentrations ranged from 1% to 80% of the saturation vapor pressure (Ps) for TCE, and exposure times (i.e., time allowed for sorption before desorption begins) ranged from 1 to 96 days. A spherical diffusion model based on a gamma distribution of sorption rates and a gamma distribution of desorption rates was developed and applied to the data. At 80% P/Ps, the entire gamma distributions of sorption and desorption rates were available for TCE. In accordance with a micropore filling mechanism, the fraction of these distributions available for TCE sorption decreased with decreasing P/Ps. Experimental results are consistent with a micropore-filling mechanism, where the amount of slow desorbing mass decreased with decreasing exposure time, and the fraction of slow desorbing sites filled decreased with decreasing exposure concentration. Simulation results suggest that diffusion limits the rates that micropores fill, and that rates of sorption and desorption for soil contaminated at smaller values of P/Ps are, on average, less than those at larger values of P/Ps (i.e., slow desorption rates are a function of exposure concentration). Simulation results also suggest that the model adequately describes the effects of exposure concentration and exposure time on the rates of sorption and desorption, but not on the capacity of the slow sites for TCE. This work is important because contaminant concentrations in the subsurface vary in space and time, and the proposed model represents a new and mechanistically based approach to capture the effects of this heterogeneity on slow desorption.     

含炭织物材料的吸附性能比较研究

本文以三类典型含炭织物材料为研究对象,对它们的孔结构、吸苯量和吸二正丙基硫醚（DPS）量进行测试。结果表明：三种含炭织物材料的吸附性能有较大差异,且其微孔容积与静态吸苯量和吸DPS量之间的关系呈线性关系。     

Breakthrough CO2 adsorption in bio-based activated carbons

In this work, the effects of different methods of activation on CO₂ adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO₂ activation and Potassium hydroxide (KOH) activation. CO₂ adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO₂ concentration range of 10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N₂ and CO₂ adsorption at 77 and 273 K, respectively. Central composite design was used to evaluate the combined effects of temperature and concentration of CO₂ on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm³/g and surface area of 1400 m²/g had the highest CO₂ adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO₂ and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO₂ activated carbons remained remarkably stable after 50 cycles with low temperature (160°C) regeneration.