用马尔柯夫模型预测马尾松低效林改造恢复过程

运用马尔柯夫模型对四川盆地马尾松低效林改造恢复过程中林分各层次盖度、多样性指数和灌木层物种组成的变化趋势进行了预测．结果表明：马尔柯夫模型可适用于退化森林生态系统人工恢复重建过程的研究；四川盆地马尾松低效林可以自然恢复，但采用封育补植措施则能加快恢复进程．对马尔柯夫模型及预测结果进行了讨论．     

Chemometrics methods for the investigation of methylmercury and total mercury contamination in mollusks samples collected from coastal sites along the Chinese Bohai Sea

The development and application of chemometrics methods, principal component analysis (PCA), cluster analysis and correlation analysis for the determination of methylmercury (MeHg) and total mecury (HgT) in gastropod and bivalve species collected from eight coastal sites along the Chinese Bohai Sea are described. HgT is directly determined by atomic fluorescence spectrometry (AFS), while MeHg is measured by a laboratory established high performance liquid chromatography-atomic fluorescence spectrometry system (HPLC-AFS). One-way ANOVA and cluster analysis indicated that the bioaccumulation of Rap to accumulate Hg was significantly (P<0.05) different from other mollusks. Correlation analysis shows that there is linear relationship between MeHg and HgT in mollusks samples collected from coastal sites along the Chinese Bohai Sea, while in mollusks samples collected from Hongqiao market in Beijing City, there is not any linear relationship.     

我国环境生态系统演变趋势

本文在对气候变化与环境生态系统现状进行了广泛调查的基础上，结合国内学者的研究，对近五年我国环境生态系统的演变趋势作了系统的回顾，并提出了保护我国生态系统的对策。     

催化湿法氧化处理垃圾渗滤液中Co/Bi催化剂的回收与再生

利用硝酸盐熔融法制备Co/Bi催化剂,用于催化湿法氧化(CWAO)处理垃圾渗滤液。对一次利用后的 Co/Bi催化剂进行回收和再生,在反应温度260 ℃、催化剂用量 2 g、氧分压 0. 5 MPa条件下,催化剂的回收率可达到(97. 09±0. 74)%。利用XRD、BET分析方法对新鲜制备、一次回收、一次再生、二次回收的催化剂进行表征,根据表征结果可知催化剂的活性为:新鲜制备>一次再生>二次回收>一次回收。利用上述催化剂在不同温度条件下降解垃圾渗滤液,在 280 ℃、300 ℃条件下,催化剂的活性为新鲜制备≈一次再生>一次回收,而在220 ℃、240 ℃、260 ℃条件下,则是新鲜制备>一次再生≈一次回收,表明低温条件下,一次再生的催化剂和一次回收的催化剂出现失活现象,并分析了催化剂失活的原因。     

Dechlorination and destruction of 2,4,6-trichlorophenol and pentachlorophenol using hydrogen peroxide as the oxidant catalyzed by molybdate ions under basic condition

The dechlorination and destruction of 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) under basic condition using hydrogen peroxide as the oxidant catalyzed by molybdate ions have been studied. Under ambient conditions of temperature and pressure, more than 95% of millimolar solutions of TCP and PCP can be converted to CO2 and CO, chlorinated and nonchlorinated carboxylic acid in 40 min. Up to 2.4 chloride ions per TCP and 3.5 chloride ions per PCP were released. TOC measurements indicated that 18% and 11% of the carbon was mineralized for TCP and PCP respectively after an hour of reaction. The results of ESR measurements suggested that the reaction possibly proceeded via the pathway with singlet oxygen.     

Preliminary investigation of a sensitive biomarker of organotin pollution in Chinese coastal aquatic environment and marine organisms

In nine batches of sea bivalves collected from Chinese coastal cities during the year of 2000 to 2002, a special sample named Mya arenaria was found to have strong ability of butyltin accumulation compared with the other sampled bivalves in the corresponding batches. Tributyltin compound was the predominant pollutant with the detection rate high up to 100%. Special high levels of g Sn/g were detected in some Mya arenaria samples. The results obtained showed that Mya arenaria was potentially a biomarker to indicate organotin pollution in coastal aquatic environment.     

Adsorption of arsenate on soils. Part 1: laboratory batch experiments using 16 Chinese soils with different physiochemical properties

Laboratory batch experiments were carried out to study the adsorption of arsenate on 16 Chinese soils with different physicochemical properties. Wide differences in arsenate adsorption were observed, and the Jiangxi and Hubei soils were more effective sorbents for arsenate than other soils. The Langmuir one-surface and two-surface equations were used to model the arsenate adsorption data. Except for the Jiangxi and Hubei soils, the Langmuir one-surface equation gave reasonably good fits to the arsenate adsorption data. However, the Langmuir two-surface equation generally provided a better fit than the Langmuir one-surface equation. For soils with relative high organic matter (OM), dissolved organic carbon (DOC) or extractable phosphate, the Langmuir one-surface and two-surface equations described the adsorption isotherms similarly. In contrast, for soils with relatively low contents of OM, DOC or extractable phosphate, the Langmuir two-surface equation gave the better fit to the arsenate adsorption data.     

Photocatalysis enhancement by electric field: TiO2 thin film for degradation of dye X-3B

According to the theory of photocatalysis, the efficiency of photocatalysis decreases mostly due to the recombination of photo-generated electron-hole pairs. An electric field across a photocatalyst can promote the separation of photo-generated electrons and holes and prevent them from recombination so as to enhance the efficiency of photocatalysis. And the synergetic decomposition efficiency of photocatalysis and an electric field is greater than that of the simple combine of their single efficiency. The performance of photocatalysis enhanced by electric field (PEEF) and operating conditions such as the direction of the electric field, the voltages between the two electrodes, the material of the electrodes, which may affect the efficiency of PEEF, were investigated in this paper. The results indicate that the system of PEEF abides the established theory of photocatalysis.     

医疗废物中有机质的热解动力学研究

在空气气氛下，对医疗废物中几种有代表性的有机质进行非等温热解实验。分析实验结果发现，热解失重曲线与N2气氛下不同，出现多个DTG峰。利用Freeman—CarroⅡ法求出了各有机质的表观动力学参数，并建立了能较好反映各物料失重过程的表观多步反应动力学模型。针对混合物料无法直接求出表观动力学参数，建立了多组分反应动力学模型。