The surface properties of fluorite are often affected by dissolved gangue species(e.g.,calcite)during the flotation process.Microflotation testing with and without the addition of calcite supernatant was conducted usi...The surface properties of fluorite are often affected by dissolved gangue species(e.g.,calcite)during the flotation process.Microflotation testing with and without the addition of calcite supernatant was conducted using octanohydroxamic acid(OHA)as the collector.The results revealed that dissolved calcite species significantly affected the flotation behavior of fluorite.Fourier transform infrared spectra confirmed that the decrease in flotation recovery was linked to lower OHA adsorption.Solution chemistry analysis indicated that CaCO_(3) and Ca^(2+)from the calcite supernatant were the most favorably adsorbed species,and X-ray photoelectron spectroscopy analysis confirmed the surface adsorption of calcite species.Density functional theory simulations provided a detailed analysis of the multidentate adsorption configuration of OHA,which was the most favorable for adsorption on the fluorite surface.The adsorption energy calculation showed that the calcite dissolved species were more stably adsorbed on the fluorite surface than OHA.The pre-adsorption of calcite dissolved species hindered the adsorption of OHA due to electrostatic repulsion.展开更多
This paper presents a method for differen- tial collision attack of reduced FOX block cipher based on 4-round distinguishing property. It can be used to attack 5, 6 and 7-round FOX64 and 5-round FOX128. Our attack has...This paper presents a method for differen- tial collision attack of reduced FOX block cipher based on 4-round distinguishing property. It can be used to attack 5, 6 and 7-round FOX64 and 5-round FOX128. Our attack has a precomputation phase, but it can be obtained before attack and computed once for all. This attack on the reduced to 4-round FOX64 requires only 7 chosen plaintexts, and performs 242.8 4-round FOX64 encryptions. It could be extended to 5 （6, 7）-round FOX64 by a key exhaustive search behind the fourth round.展开更多
Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hy...Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be obtained.Large- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.展开更多
Combustible gases in coal mines are composed of methane, hydrogen, some multi-carbon alkane gases and other gases. Based on a numerical calculation, the explosion limits of combustible gases were studied, showing that...Combustible gases in coal mines are composed of methane, hydrogen, some multi-carbon alkane gases and other gases. Based on a numerical calculation, the explosion limits of combustible gases were studied, showing that these limits are related to the concentrations of different components in the mixture. With an increase of C4H10 and C6H14, the Lower ExplosionLimit （LEL） and Upper Explosion-Limit （UEL） of a combustible gas mixture will decrease clearly. For every 0.1% increase in C4H10 and C6H14, the LEL decreases by about 0.19% and the UEL by about 0.3%. The results also prove that, by increasing the amount of H2, the UEL of a combustible gas mixture will increase considerably. If the level of HE increases by 0.1%, the UEL will increase by about 0.3%. However, H2 has only a small effect on the LEL of the combustible gas mixture. Our study provides a theoretical foundation for judging the explosion risk of an explosive gas mixture in mines.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(Nos.51874247,51922091,51904249)Young Elite Scientists Sponsorship Program by CAST,China(No.2018QNRC001)+2 种基金Sichuan Science and Technology Program,China(Nos.2019YFS0453,2018JY0148)Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization,China(No.CNMRCUKF2001)Postgraduate Innovation Fund by Southwest University of Science and Technology,China(No.20ycx0027).
文摘The surface properties of fluorite are often affected by dissolved gangue species(e.g.,calcite)during the flotation process.Microflotation testing with and without the addition of calcite supernatant was conducted using octanohydroxamic acid(OHA)as the collector.The results revealed that dissolved calcite species significantly affected the flotation behavior of fluorite.Fourier transform infrared spectra confirmed that the decrease in flotation recovery was linked to lower OHA adsorption.Solution chemistry analysis indicated that CaCO_(3) and Ca^(2+)from the calcite supernatant were the most favorably adsorbed species,and X-ray photoelectron spectroscopy analysis confirmed the surface adsorption of calcite species.Density functional theory simulations provided a detailed analysis of the multidentate adsorption configuration of OHA,which was the most favorable for adsorption on the fluorite surface.The adsorption energy calculation showed that the calcite dissolved species were more stably adsorbed on the fluorite surface than OHA.The pre-adsorption of calcite dissolved species hindered the adsorption of OHA due to electrostatic repulsion.
基金This work has been performed in the Project "The Research on the New Analysis in Block Ciphers" supported by the Fundamental Research Funds for the Central Universities of China，the National Natural Science Foundation of China，the 111 Project of China，the Scientific Research Foundation of Education Department of Shaanxi Provincial Government of China
文摘This paper presents a method for differen- tial collision attack of reduced FOX block cipher based on 4-round distinguishing property. It can be used to attack 5, 6 and 7-round FOX64 and 5-round FOX128. Our attack has a precomputation phase, but it can be obtained before attack and computed once for all. This attack on the reduced to 4-round FOX64 requires only 7 chosen plaintexts, and performs 242.8 4-round FOX64 encryptions. It could be extended to 5 （6, 7）-round FOX64 by a key exhaustive search behind the fourth round.
基金Supported by the Doctoral Foundation of China (20050251006)
文摘Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be obtained.Large- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.
基金Projects 706029 supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project of Ministry of Education of China2007AA04Z332 by the National High Technology Research and Development Program of China
文摘Combustible gases in coal mines are composed of methane, hydrogen, some multi-carbon alkane gases and other gases. Based on a numerical calculation, the explosion limits of combustible gases were studied, showing that these limits are related to the concentrations of different components in the mixture. With an increase of C4H10 and C6H14, the Lower ExplosionLimit （LEL） and Upper Explosion-Limit （UEL） of a combustible gas mixture will decrease clearly. For every 0.1% increase in C4H10 and C6H14, the LEL decreases by about 0.19% and the UEL by about 0.3%. The results also prove that, by increasing the amount of H2, the UEL of a combustible gas mixture will increase considerably. If the level of HE increases by 0.1%, the UEL will increase by about 0.3%. However, H2 has only a small effect on the LEL of the combustible gas mixture. Our study provides a theoretical foundation for judging the explosion risk of an explosive gas mixture in mines.
