Land use Systems and Erosion in the Uplands of the Central Coast, Vietnam

Soil erosion is a significant problem in the uplands of the Central Coast, Vietnam. It affects the livelihood of farmers and could hinder the long-term economic development efforts in the uplands. Yet, trapped in poverty, upland farmers, especially the ethnic minority, are still mining the soil using erosive land use systems to meet their urgent needs. This study demonstrates that the level of soil erosion varies across the typical land use systems. The fruit tree-based agroforestry (AF) system is least erosive and most financially profitable. The choice of land use system is influenced by farmers' attributes, land plot characteristics, and policy-related variables. The set of policy variables is important in explaining land use choice by upland farmers. Promoting the switch to AF system and the adoption of soil conservation is of great importance to reducing soil erosion and sustaining development in the uplands. However, it is a very challenging task.     

不同交联度PP-g-4VP离子交换纤维的制备及对水溶液中铬离子吸附的研究

通过控制交联剂(DVB)及单体(4-VP)浓度等工艺,研制了不同交联度的聚丙烯接枝4乙烯基吡啶离子交换纤维(PP-g-4VP),旨在改善纤维的结构及其再生吸附和重复使用性能。实验结果表明,随着DVB含量增大,纤维的接枝率下降,交联度增加,而吸水率下降。所制的PP-g-4VP和PP-g-4VP-季铵盐纤维对Cr~(6+)静态吸附量大,分别达约6.5mmol/g和4mmol/g。交联度低时,纤维对Cr~(6+)吸附速度越快,穿透点前流出液浓度较低。纤维吸附Cr~(6+)后用1N NH_3·H_2O能完全洗脱,再生吸附性能良好。     

Treatment of phenol wastewater by microwave-induced CIO_2-CuO_x/Al_2O_3 catalytic oxidation process

The catalyst of CuO_x/Al_2O_3 was prepared by the dipping-sedimentation method usingγ-Al_2O_3 as a supporter.CuO and Cu_2O were loaded on the surface of Al_2O_3,characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).In the presence of CuO_x/Al_2O_3,the microwave-induced chlorine dioxide(ClO_2) catalytic oxidation process was conducted for the treatment of synthetic wastewater containing 100 mg/L phenol.The factors influencing phenol removal were investigated and the results showed that microwave-induced ClO_2-CuO_x/Al_2O_3 process could effectively degrade contaminants in a short reaction time with a low oxidant dosage,extensive pH range.Under a given condition(ClO_2 concentration 80 mg/L,microwave power 50 W,contact time 5 min,catalyst dosage 50 g/L,pH 9),phenol removal percentage approached 92.24%,corresponding to 79.13% of COD_(Cr) removal.The removal of phenol by microwave-induced ClO_2-CuO_x/Al_2O_3 catalytic oxidation process was a complicated non-homogeneous solid/water reaction, which fitted pseudo-first-order by kinetics.Compared with traditional ClO_2 oxidation,ClO_2 catalytic oxidation and microwave-induced ClO_2 oxidation,microwave-induced ClO_2 catalytic oxidation system could significantly enhance the degradation efficiency.It provides an effective technology for the removal of phenol wastewater.     

A study on "selenium-health" database in China

A database for "Se and health" has been established using DATA-TRIEVE data management system on a VAX-11/780 computer. Over 5000 pieces of information including 300 kinds of samples from 28 provinces in China were stored. The information relates to endemk diseases such as Keshan disease, Kaschin-Beck disease, Se-poison disease, cancers, heart disease and so on. The database can be accessed through keywords: samples, province, county, analytical method and the Se-content values can be obtained in tabulated form. The output includes primary statistics of the retrieved data sets. A multi-variable statistic program package featuring in pattern recognition is attached to the system.     

我国城市生活垃圾处理行业2006年发展报告

本文介绍了2006年我国城市生活垃圾处理有关标准的政策进展和城市生活垃圾处理设施的建设和运行情况,并对行业发展进行了展望。     

我国机动车污染防治行业2006年发展报告

本文综述了我国机动车污染防治行业的发展现状,提出了行业发展面临的主要问题及对策建议,并对行业的发展前景进行了展望。     

载体对生物质油裂解镍基催化剂的性能影响

以改性处理的CaA分子筛、硅藻土和ZrO_2-CeO_2复合氧化物为载体,分别负载镍制备催化剂,并采用XRD、SEM、TPR、TG、FT-IR对催化剂的结构、形貌、表面酸中心种类、还原性能和积碳性能等进行了表征。结果表明,载体的种类影响催化剂性能,改性后的Ca A分子筛具有较大的比表面积和孔容,负载镍基催化剂表面具有较强的L酸和B酸中心,能与镍物种形成较强的相互作用,在生物质油催化裂解反应中表现出较好的活性,同时催化剂表面较强的酸中心也促进了积碳前驱物的形成;而Ni O/硅藻土催化剂和NiO/ZrO_2-CeO_2催化剂的酸中心强度相对较弱,影响了活性组分与载体的相互作用,活性组分在反应中烧结现象明显。