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．     

Spectroscopic characterization of the structural and functional properties of natural organic matter fractions

Natural organic matter (NOM) is known to be complex in nature with varying structural and functional characteristics. In this study, an aquatic NOM was fractionated into the polyphenolic-rich (NOM-PP) and the carbohydrate-rich (NOM-CH) fractions in an attempt to better characterize their chemical and structural properties along with a reference soil humic acid (SHA). Various spectroscopic techniques were employed for the study, including ultraviolet-visible (UV/Vis). 13C-nuclear magnetic resonance, Fourier-transform infrared, fluorescence, and electron paramagnetic resonance spectroscopies. Results indicate that the relative abundance of aromatic C=C and methoxyl (-OCH3) functional groups are in the order of SHA > NOM-PP > NOM-CH. However, the aquatic NOM-PP and NOM-CH fractions are characterized by high contents of carboxylic and alcoholic functional groups relative to the SHA. In particular, the NOM-PP fraction appears to contain more phenolic and ketonic functional groups than the NOM-CH and SHA fractions, and it gives a strong fluorescence and high paramagnetic spin count. On the other hand, the NOM-CH fraction possesses a relatively low amount of carbon but a high amount of oxygen or oxygen-containing structural features, such as carbohydrate-OH and carboxylic groups, and shows the least fluorescence intensity and paramagnetic spin counts. Results of these spectroscopic studies confirm the heterogeneous nature of NOM, and point out the importance of isolation and improved characterization of various NOM subcomponents in order to better understand the behavior and roles of NOM in the natural environment.     

高架复合道路噪声声场分布研究

高架复合道路有效地缓解了交通拥挤的问题，但随之也带来了严重的噪声污染，以几何声学和衍射声学为理论基础，利用声级叠加原理，建立了高架复合道路噪声对临街建筑立面影响的预测模式。预测值与实测值基本相符，可直接应用于城市噪声预测。为城市发展规划尤其是城市高架复合道路的发展提供了科学依据。     

溶液中阴离子对UV/H2O2降解十二烷基苯磺酸钠的影响及其机理

研究了UV/H2O2工艺对十二烷基苯磺酸钠(LAS)的去除效果、溶液中阴离子对LAS降解的影响及机理.结果表明:UV/H2O2工艺可以有效地去除水中的LAS;在H2O2投加量为8 mg/L,14 W低压汞灯照射下,LAS在蒸馏水和自来水中的反应速率常数分别为0.018 0 、0.012 2 min-1;NO-3、Cl-、SO2-4和HCO-3对LAS光降解有抑制作用,当该4种离子摩尔浓度均分别为5、10、15 mmol/L时,对LAS光降解的抑制程度为HCO-3》NO-3》Cl-》SO2-4,且随着离子摩尔浓度的增大,抑制作用增强;LAS在自来水中的反应速率常数低于在蒸馏水中的反应速率常数是由于水中多种离子影响的结果.     

Influences of dissolved and colloidal organic carbon on the uptake of Ag, Cd, and Cr by the marine mussel Perna viridis

The cross-flow ultrafiltration and radiotracer techniques were used to study the influences of natural dissolved organic carbon (DOC) and colloidal organic carbon (COC) on the bioavailability of Ag, Cd, and Cr to the green mussel Perna viridis. We examined the uptake of these metals by the mussels at different concentrations of DOC and COC from different origins (estuarine, coastal, and diatom decomposed). Using the DOC originating from the decomposed diatom (Thalassiosira pseudonana), we demonstrated that Cd and Cr uptake, quantified by the concentration factor (DCF), increased linearly with increasing DOC concentration. There was, however, no consistent influence of natural DOC concentration on the metal uptake when the DOC was obtained from different sources of seawater (coastal and estuarine). The influences of COC on metal bioavailability were metal-specific and dependent on the geochemical properties of colloids and colloid-metal complexation. Cd uptake rate was not influenced by the COC concentrations. Uptake of diatom-decomposed colloidal Cr was enhanced by 3.4x, whereas the uptake of diatom-decomposed colloidal Ag was decreased by 8.2x compared with the uptake of low molecular weight Cr and Ag (<1 kDa). The uptake of diatom-decomposed colloidal Cr and Ag was generally lower than the uptake of metals bound with the same type of colloids for 2 days. Further aging of the colloid-metal binding reduced metal bioavailability to the mussels. In the presence of different sizes of colloidal particles where there was no major binding of colloids with the metals, metal uptake by the mussels was not influenced by different COC concentrations. Overall, our study suggests that although metal dissociation from colloids may be an important step for the uptake of colloidal metals, other mechanisms such as pinocytosis and co-transport may also be involved in the uptake of these metals, especially in aquatic environments with high DOC and COC concentrations.     

Levels of 2,3,7,8-Tetrachlorodibenzo- -dioxin (2,3,7,8-TCDD) in adipose tissue of U.S. Vietnam veterans seeking medical assistance

2,3,7,8-Tetrachlorodibenzo- -dioxin (2,3,7,8-TCDD) was detected in an earlier study in adipose tissue of U.S. veterans who were exposed to Agent Orange in Vietnam. The levels appear to be directly related to the intensity of exposure¹. We now report on a group of thirteen Vietnam veterans who were screened for 2,3,7,8-TCDD in adipose tissue. All the veterans had sought medical assistance and some had health effects that may be ascribed to exposure to 2,3,7,8-TCDD. Also included are control patients who were taken from the population of the U.S. 2,3,7,8-TCDD was detected in most of the adipose tissue samples at levels ranging from 2 to 14 ppt. No significant differences in the tissue levels of Vietnam veterans and the other persons were found in this preliminary study.     

双循环两相生物处理工艺工程应用的探讨

探讨了新型生物脱氮除磷工艺--双循环两相(BICT)生物处理工艺的生产规模应用问题.通过在序批式活性污泥法基础上增设独立的生物膜反应器,实现微生物的分相培养,BICT工艺为提高系统的脱氮除磷能力,增强运行稳定性和可靠性创造了条件.技术经济比较分析说明,BICT工艺技术先进、运行稳定,投资及运行费用具有竞争力,在污水处理要求愈加严格的情况下,具有推广价值和应用前景.     

SBR工艺处理糠醛废水研究

将糠醛厂塔底废水与其他生产废水混合,利用SBR工艺进行处理,研究了运行工况、污泥负荷和进水pH等对处理效果的影响.结果表明,反应操作灵活;适宜运行参数为pH 6～8,进水10 min,搅拌100 min,曝气120 min,沉淀120 min,出水10min;当进水COD≤950 mg/L,日污泥负荷MCOD/MMLSS=0.346时,出水COD＜100 mg/L.     

膜生物反应器的研究及在废水处理中的应用

综合论述了膜生物反应器的发展概况、基本原理、技术特点及分类等。     

鸭河口水库水体总氮、总磷预测研究

根据鸭河口水库受纳点源及面源污染负荷情况，选择枯水期为预测时期，采用迪隆模型对鸭河口水库水体总氮、总磷进行预测研究，为鸭河口水库水质保持和富营养化防治提供基础数据。