Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the ...Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.展开更多
With the continuous development of education in our country,the demand for talents in all aspects of society is increasing gradually,carry out ideological and political education for students.In order to cultivate the...With the continuous development of education in our country,the demand for talents in all aspects of society is increasing gradually,carry out ideological and political education for students.In order to cultivate the ideological and political talents needed by the society,we should deepen the reform and political education and introduce the educational concept into the actual ideological and political education.lleges and universities,and discusses the problems in teaching and the measures to strengthen teaching in detail for the reference of relevant departments.展开更多
Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differen...Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differences.These differences,compounded by the demands of the new liberal arts reform,place significant challenges and pressure on elective course instructors.To meet these demands,elective course teachers should enhance their teaching methods and explore new instructional models.The International Trade in Services course,for instance,has implemented six areas of curriculum reform,enriching the practice of elective course improvement.展开更多
基金the financial support by the Natural Science Foundation of Liaoning Province of China (Grant No. 2013020122)the National Natural Science Foundationof China (Grant No. 21076100 and 51308045)the financial support by the PetroChina Company Limited (Grant No. 10-01A-01-01-01)
文摘Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.
文摘With the continuous development of education in our country,the demand for talents in all aspects of society is increasing gradually,carry out ideological and political education for students.In order to cultivate the ideological and political talents needed by the society,we should deepen the reform and political education and introduce the educational concept into the actual ideological and political education.lleges and universities,and discusses the problems in teaching and the measures to strengthen teaching in detail for the reference of relevant departments.
文摘Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differences.These differences,compounded by the demands of the new liberal arts reform,place significant challenges and pressure on elective course instructors.To meet these demands,elective course teachers should enhance their teaching methods and explore new instructional models.The International Trade in Services course,for instance,has implemented six areas of curriculum reform,enriching the practice of elective course improvement.
