苯甲酸钠降解菌的分离及Tn5诱变

采用富集法从柴油污染的土壤中分离到一株能以苯甲酸钠为唯一碳源而生长的产水溶性荧光色素的Pseudomonas sp,其荧光色素在121℃、30min不被破坏.通过转座子Tn5插入诱变,再次证明Tn5所携km~Rsm~R基因可在革兰氏阴性菌Pseudomonas sp中表达,其Sm~Rkm~R双抗突变频率为10~(-6)-10~(-7)/受体细胞,从上述双抗子中可再选出功能突变菌落,频率约0.5％.其中有2株为荧光消失型,2株为荧光增强型,1株为苯甲酸钠利用能力缺陷型,1株为营养缺陷型,2株为生长缓慢型.     

可接受风险的界定方法探讨

着重论述了可接受风险的概念及界定方法 ,丰富了风险研究的理论及方法 ,旨在为风险管理提供更加有意义的参考。     

Research on low emission MSW gasification and melting system

In order to eliminate secondary pollution caused by municipal solid waste (MSW) incineration, a MSW gasification and melting process is proposed. The process is expected to reduce the emission of pollutants, especially heavy-metals and dioxins. In this paper, the combustible components of MSW and simulated MSW were gasified in a lab-scale fluidized bed at 400°C–700°C when the excess air ratio (ER) was between 0.2 and 0.8. The experimental results indicated that the MSW could be gasified effectively in a fluidized bed at approximately 600°C–700°C when excess air ratio was 0.2–0.4. The melting characteristics of two typical fly ash samples from MSW incinerators were investigated. The results indicated that fly ash of pure MSW incineration could be melted at approximately 1,300°C and that of MSW and coal co-combustion could be melted at approximately 1,400°C. When temperature was over 1,100°C, more than 99.9% of the dioxins could be decomposed and most of the heavy-metals could be solidified in the slag. Based on the above experiments, two feasible MSW gasification and melting processes were proposed for low calorific value MSW: (1) sieved MSW gasification and melting system, which was based on an idea of multi-recycle; (2) gasification and melting scheme of MSW adding coal as assistant fuel.     

偏转二次风系统600MW燃煤锅炉NOx排放特性及数值模拟

某600MW四角切圆燃烧锅炉，采用顶部燃尽风系统并配合使用偏转二次风系统，炉膛下部二次风大角度正切，上部二次风和OFA风反切消旋 ，在炉 膛截面水平方向和炉膛高度方向形成分级燃烧。运行结果表明，该燃烧器布置方式能抑制炉内结渣，减轻炉膛出口扭转残余并能降低NO x排放量。通过工况试验，将锅炉的氮氧化物排放水平降低到国家标准限定值以下，采用数值计算对该炉炉内流动、传热、燃烧和氮氧化物生成过程进行模拟。     

The effect of background irradiation on photocatalytic efficiencies of TiO2 thin films

TiO(2) thin films were prepared on quartz pipe substrates. Effects of the thickness of the films, the wavelength of the UV light and La doping on efficiencies of background irradiated photocatalysis were investigated, and simultaneously was compared with those of foreground irradiated photocatalysis. The results showed that there was an optimal thickness of the film corresponding with each wavelength of the light source limited in the range from 300 nm to 388 nm in the case of background irradiated photocatalysis, which was quite different from that of foreground irradiated one. But in both cases, the film's photocatalytic activities were enhanced by La non-uniformly doping. The results are useful for the design of high-efficiency photocatalytic reactors.     

Chelator-induced bioextraction of heavy metals from artificially contaminated soil by mushroom (Coprinus comatus)

This study investigated the potential use of chelator-induced bioextraction of heavy metals from soil by Coprinus comatus in a pot experiment. Two production waves of the mushroom were obtained to determine biomass and metal concentration. The application of ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetate (NTA) slightly inhibited the growth of C. comatus, but significantly enhanced the accumulation of heavy metals in fruiting bodies compared with the control. The highest concentrations of Pb, Cu and Cd reached 900.60, 783.61 and 23.64 mg·kg^?1 in a single pot, respectively. However, application of citric acid (CA) had no effect on metal uptake. Moreover, chelators applied to soil after fructification increased the dry biomass and metal concentration in fruiting bodies compared with those applied before sowing mycelia. EDTA was more efficient for inducing metal uptake by C. comatus than NTA or CA, and split applications of EDTA after fructification resulted in the highest total metal uptake by mushroom, i.e. 19.08±2.84, 17.57±0.69 and 0.55±0.06 mg for Pb, Cu and Cd, respectively, which were 130, 12 and 5 times values obtained with the control. Interestingly, many mushrooms turned blue after soil had been treated with chelator, indicating that these mushrooms are rich in Cu.     

挥发性有机物处理新技术的研究

随着VOCs处理要求的不断提高,新型的VOCs处理技术日益受到关注。详细分析了生物法、光催化氧化法以及等离子体催化氧化法VOCs处理新技术的研究进展。高效微生物的筛选、新型生物填充材料的研究使生物法VOCs处理更加实用;光催化剂的表面改性有助于防止催化剂钝化,保证光催化系统的长期稳定运行;等离子体催化氧化VOCs过程中能耗的降低以及副产物的控制将是下一步研究的重点。     

1949～1998年中国大洪涝灾害若干特征分析

根据1949~1998年大洪涝灾害资料、运用一般统计方法和分形理论,分析了1949~1998年大洪涝灾害的若干特征,得出大洪涝灾害的发生频率在不断增加、受灾农田面积波动上升、空间上以长江和珠江流域为主、季节上集中在6~8月份等特征,并探讨了大洪涝灾害时间序列上的分形特征。     

Frequency comparative study of coal-fired fly ash acoustic agglomeration

Comparative studies between high-frequency and lowfrequency acoustic agglomeration were carried out to investigate the frequency influence on agglomeration efficiency.     

甲苯的光氧化降解试验研究

以气相甲苯为对象,研究其在波长为254 nm紫外光下的光氧化降解反应.同时,考察了甲苯初始浓度、光强和相对湿度对甲苯转化率的影响,分析了甲苯降解中间产物的生成机理.结果表明,随着甲苯初始浓度的增加,甲苯转化率缓慢下降;随着光照强度的增强,甲苯转化率逐渐增加;而提高相对湿度,甲苯转化率则为先升高后降低.在甲苯降解动力学分析中发现其光氧化降解过程符合伪一级反应动力学,且表观速率常数与光照强度成正比.通过对甲苯降解中间产物的分析,发现随着光照强度的增加,含苯环物质的降解更为充分,乙醇、乙酸等的相对含量逐渐增加,苯甲醇、苯甲醛缩二甲醇等的含量逐渐降低,在此基础上提出了甲苯生成含苯环产物及开环生成2-戊酮等的降解机理.