Nanoscale mullite powder were synthesized via Sol-gel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde) and TEOS ( tetraethyl orthosili-cate) as starting materials. Both of the binary aerogel o...Nanoscale mullite powder were synthesized via Sol-gel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde) and TEOS ( tetraethyl orthosili-cate) as starting materials. Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC ( thermogravimetry-differentialscanning calorimeter) , TEM( transmission electron microscope) , XRD(X-Ray diffractometer ) and specific surfacearea and porosimetry. TG-DSC indicated the removal of most of the volatiles, i.e. 15.98% up to about 700℃ ,and in the DSC curve , existence of two exothermic peak atabout 445℃ and 1015℃ may be due to the crystallizationof Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules . On the colligation of the results of TG-DSC, XRD and TEM, the beginning temperature of mullitization in Al2O3-SiO2 aerogel system can be confirmed at about 1015℃. XRD results also showed the formation of mullite at the range 1100-1200℃. TEM and surface area and porosimetry results showed that the nanosized mullite were calcinated at 1100and 1200℃ exhibited size 30 nm and 50 nm, specific surface area 138.91 m2/g and 95.81 m2/g.展开更多
The complex coating on the MgO CaO clinker was prepared by dipping method and adding the second mineral to restrain the formation and expansion of the cracks. Meanwhile, the microstructure and the morphology of the c...The complex coating on the MgO CaO clinker was prepared by dipping method and adding the second mineral to restrain the formation and expansion of the cracks. Meanwhile, the microstructure and the morphology of the coating and hydration resistance of the MgO CaO clinker were also investigated. The result shows that the coating consists mainly of Ca 2P 2O 7, MgO and CaCO 3, its thickness ranges from 5μm to 20μm, and the coating is dense and even, no micro cracks are observed. Also, the coating adheres closely to the matrix. The hydration resistance of the MgO CaO clinker after treatment is improved greatly, and the castables prepared with the treated MgO CaO clinker have better physical properties than MgO castable.展开更多
Fast-growing and High-yielding Forests Base Construction Program is the only industrialization program of six key forestry programs. The main construction content is to plant 13.33 million hm fast-growing and high-yie...Fast-growing and High-yielding Forests Base Construction Program is the only industrialization program of six key forestry programs. The main construction content is to plant 13.33 million hm fast-growing and high-yielding plantation in 18 provinces in China. According to the program planning and growth of different tree species, the biomass of this program is evaluated and the C sequestration is assessed in this paper. In the program period, the biomass of the program will reach 3.703 6×109 t, and the C storage will get 1.851 8×109 t. The program will have a great effect on raising the C pool function of forest vegetation.展开更多
基金This work was supported by the project of Wuhan Science & Technology(20011007088)and Hubei province project of key problem tackling(2001AA101B07)
文摘Nanoscale mullite powder were synthesized via Sol-gel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde) and TEOS ( tetraethyl orthosili-cate) as starting materials. Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC ( thermogravimetry-differentialscanning calorimeter) , TEM( transmission electron microscope) , XRD(X-Ray diffractometer ) and specific surfacearea and porosimetry. TG-DSC indicated the removal of most of the volatiles, i.e. 15.98% up to about 700℃ ,and in the DSC curve , existence of two exothermic peak atabout 445℃ and 1015℃ may be due to the crystallizationof Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules . On the colligation of the results of TG-DSC, XRD and TEM, the beginning temperature of mullitization in Al2O3-SiO2 aerogel system can be confirmed at about 1015℃. XRD results also showed the formation of mullite at the range 1100-1200℃. TEM and surface area and porosimetry results showed that the nanosized mullite were calcinated at 1100and 1200℃ exhibited size 30 nm and 50 nm, specific surface area 138.91 m2/g and 95.81 m2/g.
文摘The complex coating on the MgO CaO clinker was prepared by dipping method and adding the second mineral to restrain the formation and expansion of the cracks. Meanwhile, the microstructure and the morphology of the coating and hydration resistance of the MgO CaO clinker were also investigated. The result shows that the coating consists mainly of Ca 2P 2O 7, MgO and CaCO 3, its thickness ranges from 5μm to 20μm, and the coating is dense and even, no micro cracks are observed. Also, the coating adheres closely to the matrix. The hydration resistance of the MgO CaO clinker after treatment is improved greatly, and the castables prepared with the treated MgO CaO clinker have better physical properties than MgO castable.
文摘Fast-growing and High-yielding Forests Base Construction Program is the only industrialization program of six key forestry programs. The main construction content is to plant 13.33 million hm fast-growing and high-yielding plantation in 18 provinces in China. According to the program planning and growth of different tree species, the biomass of this program is evaluated and the C sequestration is assessed in this paper. In the program period, the biomass of the program will reach 3.703 6×109 t, and the C storage will get 1.851 8×109 t. The program will have a great effect on raising the C pool function of forest vegetation.
