Competition of Hydrogen and Manganese Ions for Adsorption Sites in Sitka Spruce Litter

The competition of hydrogen and manganese ions for adsorption sites in Sitka spruce litter was investigated in a factorial design, simulated acid rain experiment, which involved leaching of litter with simulated throughfall solutions at three pH levels (5.3, 4.3 and 3.3) and three manganese concentrations (0 to 0.2 mg1^-1). the throughfall solution at the lowest pH was the most efficient in removing exchangeable manganese from litter. the manganese concentration in the leachates was approximately proportional to the hydrogen ion concentration in the simulated throughfall solution. Under field conditions, throughfall manganese concentration also naturally tends to increase as a consequence of enhanced foliar leaching of manganese in response to increasing precipitation acidity. the manganese concentration in the simulated throughfall also affected manganese concentration in the leachates, however, and contributed to a buildup of exchangeable manganese in litter, thus counteracting to some extent possible adverse effects of excess leaching due to increased throughfall acidity.     

植物载体固定化无花果曲霉对直接冻黄G的脱色研究

利用植物载体丝瓜瓤对元花果曲霉进行固定,并对直接冻黄G进行脱色研究.同时考察了不同因素如菌龄、温度、pH、转速对直接冻黄G的脱色影响.试验结果表明:三龄菌丝脱色效果最佳,该菌在30℃、pH 6.0、90r/min的振荡条件下,经12 h它对直接冻黄G的脱色达到最佳效果.固定化细胞经8次脱色后,脱色率仍达94%以上.因此用丝瓜瓤固定无花果曲霉对处理染料污染废水具有较好的应用前景.     

Effect of initial temperature on the explosion pressure of various liquid fuels and their blends

In this work, the effect of initial temperature on the explosion pressure, P_ex, of various liquid fuels (isooctane, toluene and methanol) and their blends (isooctane-toluene and methanol-toluene, with three different fuel-fuel ratios) was investigated by performing experiments in a 20-l sphere at different concentrations of vaporized fuel in air. The initial temperature was varied from 333 K to 413 K.Results show that, as the fuel-air equivalence ratio, Φ, is increased, a transition occurs from a “thermodynamics-driven” explosion regime to a “radiant heat losses-driven” explosion regime. The maximum pressure, P_max, is found in the former regime (Φ < 3), which is characterized by a trend of decreasing P_ex with increasing initial temperature. This trend has been explained by thermodynamics. In the latter regime (Φ > 3), P_ex increases with increasing initial temperature. This trend has been addressed to the decrease in emissivity (and, thus, radiant heat losses) with the increase in temperature.     

ASM2G在污水处理中的研究与应用

针对用静态模型常规设计在设计效果与模拟分析上的不足,作者在研究动态机理模型ASM2d的基础上开发了污水处理仿真程序ASM2G,以分析污水生物处理,并进行模拟分析与辅助设计.本文首先介绍了此自编程序的机理模型ASM2d;其次说明了ASM2G的模拟过程;最后,通过对实际污水处理厂的模拟比较,说明了ASM2G在模拟分析上的优势,同时也反映了ASM2d能够较好地反映污水处理的运行状况,是一个较成熟的动态机理模型.文章试图为找到一种经济有效的设计方法提供一定的参考.     

Improvement of antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20

Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes(PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy(ATR/FT-IR)and field emission scanning electron microscope(FE- SEM)were used to characterize the chemical and morphological changes on the membrane surfaces.Water contact angles and relative pure water fluxes were measured.The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes.To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor(MBR),filtration for active sludge was performed using synthetic wastewater.With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d,the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied.     

BT20钛合金筒形件的UOE热成形

阐述了用UOE热成形BT20钛合金筒形件的特点。通过对BT20筒形件UOE热成形的实验研究,确定了BT20钛合金筒形件UOE热成形工艺过程,得到了一系列成形工艺参数及在成形过程中控制产品质量的措施。     

氮掺杂型纳米TiO2在可见光及太阳光下的光催化性能研究

采用钛酸四丁酯为原料,以氨水水解-沉淀法制备出了氮掺杂型纳米TiO2催化剂(N/TiO2),以XRD、XPS、UV-Vis等手段对其进行表征;并通过对偶氮染料橙黄G的降解反应,研究了N/TiO2在可见光及太阳光下的光催化性能,探讨了pH值、外加H2O2氧化剂对光催化降解率的影响,并与P25型纳米TiO2进行了对比.结果表明,在可见光下,N/TiO2对橙黄G具有较高的催化活性,反应150min后降解率可达96.29%,显著高于P25型TiO2(42.55%);在太阳光下,N/TiO2对橙黄G的光催化降解速率较快,反应60min降解率与P25型TiO2基本相同,分别为99.37%、99.94%;较低的pH值环境并适量添加H2O2可显著提高N/TiO2催化效率,在可见光及太阳光下的最佳pH值均为2～3,最佳H2O2加入量分别为0.5mL·L-1、1.5 mL·L-1.     

锰砂催化电化学方法对染料K2G脱色效果的研究

研究了锰砂催化电化学方法对偶氮染料K2G的脱色效果 .结果表明 ,锰砂中的主要成份MnOOH对电化学过程具有催化作用 ,可有效地提高染料的脱色效率 .对锰砂的X光衍射实验证明 ,反应过程中MnOOH的含量无较大变化 .染料溶液的起始pH值对其脱色率没有明显的影响 .在最佳电流密度di 为 0 2 6A·dm- 2 ,Na2 SO4 浓度为0 0 1mol·l- 1时 ,电解 70min ,浓度为 1 0 0mg·l- 1的染料K2G的脱色率能达到 99% .     

EIA training courses organized by the centre for environmental management and planning,University of Aberdeen: An analysis of experience

In 1980, the World Health Organization (Regional Office for Europe) invited The Centre for Environmental Management and Planning (CEMP) to organize a two-week training course on Environmental Impact Assessment (EIA) to provide a comprehensive introduction to EIA with emphasis on methods and techniques for impact identification, prediction and assessment. Not suprisingly the topic of environmental health impact assessment was to be a major focus. Since 1980, the course has been held each year at the University of Aberdeen. An analysis of participation in the course during its first five years yields several impressions about the success of this training effort and the ways in which it might be improved.     

川藏公路G317线路基水毁危险度分段研究

G317线是我国西藏地区最主要的干线公路之一，是内地与西藏地区经贸流通的重要通道。但是西藏地区环境恶劣，公路路基水毁灾害非常频繁，常常影响公路通行。本文从G317线公路路基水毁的实地调查资料出发，综合分析影响路基水毁发育的因素，对其水毁危险性进行分段研究。经过研究将G317线分为极度危险段、高度危险段、中度危险段、低度危险段、微度危险段和暂无危险段6个路基水毁危险度级别，并对每个危险度级别进行评述.