Based on analysis of energy dissipation in the core region of gas-solid fluidized bed risers, a simplified model for determination of core-annulus solids mass transfer coefficient was developed according to turbulent ...Based on analysis of energy dissipation in the core region of gas-solid fluidized bed risers, a simplified model for determination of core-annulus solids mass transfer coefficient was developed according to turbulent diffusion mechanism of particles. The simulation results are consistent with published experimental data. Core-annulus solids mass transfer coefficient decreases with increasing particle size, particle density and solids circulation rate,but generally increases with increasing superficial gas velocity and riser diameter. In the upper dilute region of gas-solid fluidized bed risers, core-annulus solids mass transfer coefficient was found to change little with the axial coordinate in the bed.展开更多
The aerosol optical properties and chemical components of PM2.1(particulate matter with a diameter of 2.1μm or less)were investigated at Mount Gongga on the eastern slope of the Tibetan Plateau from April 2012 to Dec...The aerosol optical properties and chemical components of PM2.1(particulate matter with a diameter of 2.1μm or less)were investigated at Mount Gongga on the eastern slope of the Tibetan Plateau from April 2012 to December 2014.The annual mean aerosol optical depth(AOD)was 0.35±0.23,and the?ngstr?m exponent was 1.0±0.38.The AOD exhibited higher values in summer and winter,but lower values in spring and autumn.Dividing the observational periods into dry and wet seasons,the authors found that the concentrations of K^+,elemental carbon,secondary inorganic aerosols,and primary and secondary organic carbon in the dry(wet)season were 0.29(0.21),0.88(0.60),7.4(4.5),7.5(5.1),and 3.9(12)μg m?3,respectively.Combined with trajectory analysis,the authors found that higher concentrations of K^+,elemental carbon,and primary organic carbon indicated the effects of biomass burning from Southeast Asia during the dry season.However,the oxidation of volatile organic compounds was the main source of aerosols during the wet season,which originated from the Sichuan Basin.展开更多
The aim of this study was to analyze the chemical composition of landrace seeds of rice, maize and cassava grown in traditional communities in file state of Maranchao. The sample collection was based on file descripti...The aim of this study was to analyze the chemical composition of landrace seeds of rice, maize and cassava grown in traditional communities in file state of Maranchao. The sample collection was based on file description of the farmers for identification of varieties of plants, based on protein content, lipids, carbohydrates and mineral through Association of Official Analytical Chemists （AOAC） methods. Landrace seeds of nine maize cultivars, 13 rice and 40 cassava, with differences in centesimal composition in all varieties were analyzed. For maize landrace seeds file lipid values, carbohydrates and ash are in the average for the species. The protein contents and ash to file surveyed rice varieties were high, while the levels of lipids and carbohydrates are within average in relation to conventional varieties. The results obtained for cassava showed high percentages of protein, with a significant level for the feeding of the people of the community who consume their byproducts. Thus, differences in file chemical composition of file varieties studied showed file interference of genotype, management and environmental factors in their chemical and physiological quality, reinforcing file importance of file study of creole varieties for the development of new germplasm and for file guarantee of food sovereignty of traditional communities.展开更多
Recently,ultrasonic waves had been introduced as the transmission medium in Body Area Networks(BANs) to reduce the incalculable damage caused by radio waves. However,the communications based on ultrasonic waves suffer...Recently,ultrasonic waves had been introduced as the transmission medium in Body Area Networks(BANs) to reduce the incalculable damage caused by radio waves. However,the communications based on ultrasonic waves suffer from poor propagation of signals in air and consume too much energy. To address these limitations,firstly,we make the theoretical analysis to ensure ultrasonic waves could be used in BANs(UBANs). Then,we propose an error control strategy in UBANs to dynamically adjust the error control scheme and the Max-Retries based on the current channel state,which is called UECS. The UECS is based on IEEE 802.15.6 standards and considering the characteristics of ultrasonic waves in BANs. Simulation results show that UECS achieves better performance in terms of packet delivery ratio and energy consumption compared with the traditional strategies.展开更多
文摘Based on analysis of energy dissipation in the core region of gas-solid fluidized bed risers, a simplified model for determination of core-annulus solids mass transfer coefficient was developed according to turbulent diffusion mechanism of particles. The simulation results are consistent with published experimental data. Core-annulus solids mass transfer coefficient decreases with increasing particle size, particle density and solids circulation rate,but generally increases with increasing superficial gas velocity and riser diameter. In the upper dilute region of gas-solid fluidized bed risers, core-annulus solids mass transfer coefficient was found to change little with the axial coordinate in the bed.
基金supported by the National Basic Research Program of China[grant numbers 2016YFC0202001 and 973Program 2014CB441200]the National Natural Science Foundation of China[grant numbers 41375036 and41305076]
文摘The aerosol optical properties and chemical components of PM2.1(particulate matter with a diameter of 2.1μm or less)were investigated at Mount Gongga on the eastern slope of the Tibetan Plateau from April 2012 to December 2014.The annual mean aerosol optical depth(AOD)was 0.35±0.23,and the?ngstr?m exponent was 1.0±0.38.The AOD exhibited higher values in summer and winter,but lower values in spring and autumn.Dividing the observational periods into dry and wet seasons,the authors found that the concentrations of K^+,elemental carbon,secondary inorganic aerosols,and primary and secondary organic carbon in the dry(wet)season were 0.29(0.21),0.88(0.60),7.4(4.5),7.5(5.1),and 3.9(12)μg m?3,respectively.Combined with trajectory analysis,the authors found that higher concentrations of K^+,elemental carbon,and primary organic carbon indicated the effects of biomass burning from Southeast Asia during the dry season.However,the oxidation of volatile organic compounds was the main source of aerosols during the wet season,which originated from the Sichuan Basin.
文摘The aim of this study was to analyze the chemical composition of landrace seeds of rice, maize and cassava grown in traditional communities in file state of Maranchao. The sample collection was based on file description of the farmers for identification of varieties of plants, based on protein content, lipids, carbohydrates and mineral through Association of Official Analytical Chemists （AOAC） methods. Landrace seeds of nine maize cultivars, 13 rice and 40 cassava, with differences in centesimal composition in all varieties were analyzed. For maize landrace seeds file lipid values, carbohydrates and ash are in the average for the species. The protein contents and ash to file surveyed rice varieties were high, while the levels of lipids and carbohydrates are within average in relation to conventional varieties. The results obtained for cassava showed high percentages of protein, with a significant level for the feeding of the people of the community who consume their byproducts. Thus, differences in file chemical composition of file varieties studied showed file interference of genotype, management and environmental factors in their chemical and physiological quality, reinforcing file importance of file study of creole varieties for the development of new germplasm and for file guarantee of food sovereignty of traditional communities.
基金partly supported by the National Natural Science Foundation of China(Grant No.61272412)Project 2016194 Supported by Graduate Innovation Fund of Jilin UniversitySpecialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20120061110044
文摘Recently,ultrasonic waves had been introduced as the transmission medium in Body Area Networks(BANs) to reduce the incalculable damage caused by radio waves. However,the communications based on ultrasonic waves suffer from poor propagation of signals in air and consume too much energy. To address these limitations,firstly,we make the theoretical analysis to ensure ultrasonic waves could be used in BANs(UBANs). Then,we propose an error control strategy in UBANs to dynamically adjust the error control scheme and the Max-Retries based on the current channel state,which is called UECS. The UECS is based on IEEE 802.15.6 standards and considering the characteristics of ultrasonic waves in BANs. Simulation results show that UECS achieves better performance in terms of packet delivery ratio and energy consumption compared with the traditional strategies.
