Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO...Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3.OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.展开更多
This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex character...This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg’s limit test,compaction test, direct shear test, California bearing ratio(CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density(MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.展开更多
利用多功能 X 射线光电子能谱(XPS)分析方法,研究了三维孔道结构化合物 (H_3NCH_2CH_2NH_2)_4[V~Ⅲ(H_2O)_2(V~ⅣO)_8(OH)_4(HPO_4)_4(PO_4)_4(H_2O)_2]·3H_2O(简称 V_9P_8-en)在不同气氛下热处理脱除模板过程中的钒氧化态变化规...利用多功能 X 射线光电子能谱(XPS)分析方法,研究了三维孔道结构化合物 (H_3NCH_2CH_2NH_2)_4[V~Ⅲ(H_2O)_2(V~ⅣO)_8(OH)_4(HPO_4)_4(PO_4)_4(H_2O)_2]·3H_2O(简称 V_9P_8-en)在不同气氛下热处理脱除模板过程中的钒氧化态变化规律及其与结构演化的关系．结果表明,380 ℃之前有机模板受热分解形成较强的还原气氛,致使骨架中部分钒被还原(V^(4+)→V^(3+))；随着钒氧化态的改变,原有的配位环境([V~ⅢO_6]八面体、[V~ⅣO_5]四方单锥)随之调整而导致结构重组．因此,热处理过程中控制钒氧化态变化将有助于保持骨架结构的稳定性．展开更多
基金financially supported by the Key Project of Chinese Ministry of Education(No.105075)the National Natural Science Foundation of China(No.20503016).
文摘Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3.OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.
文摘This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg’s limit test,compaction test, direct shear test, California bearing ratio(CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density(MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.
