Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temp...Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temperature,and reaction time on the viscosity and molecular weight of the product were investigated.The conversion under optimized conditions reached 97.3%.The product structure was characterized by ^(13)C NMR spectrometry and ~1H NMR spectrometry,and the conversion of olefins with different carbon numbers under different conditions was determined by GC analysis.The polymer obtained under optimized conditions has a high viscosity index of 262 with a narrow molecular weight distribution of 1.95,which is a desired component for lubricating base oil.展开更多
The Leibniz-Hopf algebra is the free associative algebra with one generator in each positive degree and coproduct given by the Cartan formula. Quasi-symmetric functions are a generalisation of symmetric functions [7],...The Leibniz-Hopf algebra is the free associative algebra with one generator in each positive degree and coproduct given by the Cartan formula. Quasi-symmetric functions are a generalisation of symmetric functions [7],and the algebra of quasi-symmetric functions appear as the dual of the Leibniz-Hopf algebra. The Leibniz-Hopf algebra and its dual are word Hopf algebras and play an important role in combinatorics, algebra and topology. We give some properties of words and consider an another view of proof for the antipode in the dual Leibniz-Hopf algebra.展开更多
This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is part...This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this ＂factory floor＂ to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity （k）, specific heat （c） and thermal diffusivity （~）. By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.展开更多
In oil and gas exploration and transportation, low dosage hydrate inhibitors （LDHIs） are more favorably utilized to inhibit the formation of hydrates than thermodynamic inhibitors （THs） as a trend. However, there ...In oil and gas exploration and transportation, low dosage hydrate inhibitors （LDHIs） are more favorably utilized to inhibit the formation of hydrates than thermodynamic inhibitors （THs） as a trend. However, there are no industrial products of LDHIs available domestically, and the corresponding application experience is in urgent need. In this paper, a combined hydrate inhibitor （HY-1） was synthesized after a series of reaction condition optimization, and its performance on THF hydrate inhibition was investigated using kinetic hydrate inhibitor evaluation apparatus with 6 cells bathing in air. The results show that when the reaction temperature is 60℃, the reaction time is 6 h, and the monomer： solvent ratio is 1：2, the product has the best kinetic hydrate inhibitor performance on THF hydrate. On these bases, the scale-up production of this combined hydrate inhibitor was carried out. Although the scale-up product （HY-10） performs less effectively on the THF hydrate inhibition than HY-1, it functions better than a commercial product （Inhibex501） during in-house tests. HY-10 was successfully applied to the gas production process. Field trials in northem Shaanxi PetroChina Changqing Oilfield Company （PCOC） show that 2 wt% of HY-10 is effective on natural gas hydrate inhibition. It is found through economic analysis that the use of HY-10 has obvious economi- cal advantage over methanol and Inhibex501.展开更多
Si hybrid solar cells have attracted tremendous research attention in recent years because of their low production costs and high performance. However, flexible Si hybrid solar cells have rarely been reported owing to...Si hybrid solar cells have attracted tremendous research attention in recent years because of their low production costs and high performance. However, flexible Si hybrid solar cells have rarely been reported owing to the difficulty of fabricating single-crystalline Si with good flexibility. In this study, we fabricated flexible Si/PEDOT：PSS hybrid solar cells with micro-pyramid-structured Si light absorbers using a facile approach. Compared with planar flexible hybrid solar cells with a power-conversion efficiency of 4%, solar cells with micro-pyramid-structured Si light absorbers have a higher efficiency of 6.3%. External quantum efficiency and electrochemical impedance spectroscopy measurements revealed that the solar cells with micro-pyramid-structured Si light absorbers exhibited a pronounced light-harvesting enhancement in the spectra region of 400-1,000 nm and had a smaller series resistance and larger recombination resistance compared with the planar cells, yielding a higher efficiency. Additionally, in mechanical-bending tests, the flexible solar cells with micro-pyramid-structured Si light absorbers exhibited an excellent performance stability after bending for 600 cycles. Our findings lay the foundation for the real-world applications of flexible Si/PEDOT：PSS hybrid solar cells in next-generation portable electronics.展开更多
文摘Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temperature,and reaction time on the viscosity and molecular weight of the product were investigated.The conversion under optimized conditions reached 97.3%.The product structure was characterized by ^(13)C NMR spectrometry and ~1H NMR spectrometry,and the conversion of olefins with different carbon numbers under different conditions was determined by GC analysis.The polymer obtained under optimized conditions has a high viscosity index of 262 with a narrow molecular weight distribution of 1.95,which is a desired component for lubricating base oil.
文摘The Leibniz-Hopf algebra is the free associative algebra with one generator in each positive degree and coproduct given by the Cartan formula. Quasi-symmetric functions are a generalisation of symmetric functions [7],and the algebra of quasi-symmetric functions appear as the dual of the Leibniz-Hopf algebra. The Leibniz-Hopf algebra and its dual are word Hopf algebras and play an important role in combinatorics, algebra and topology. We give some properties of words and consider an another view of proof for the antipode in the dual Leibniz-Hopf algebra.
文摘This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this ＂factory floor＂ to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity （k）, specific heat （c） and thermal diffusivity （~）. By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No.G2009CB219504)the National Sci-ence and Technology Major Project of China (Grant No.2008ZX05026-004-06)the Fundamental Research Funds for the Central Universities (Grant No.2009ZM0185)
文摘In oil and gas exploration and transportation, low dosage hydrate inhibitors （LDHIs） are more favorably utilized to inhibit the formation of hydrates than thermodynamic inhibitors （THs） as a trend. However, there are no industrial products of LDHIs available domestically, and the corresponding application experience is in urgent need. In this paper, a combined hydrate inhibitor （HY-1） was synthesized after a series of reaction condition optimization, and its performance on THF hydrate inhibition was investigated using kinetic hydrate inhibitor evaluation apparatus with 6 cells bathing in air. The results show that when the reaction temperature is 60℃, the reaction time is 6 h, and the monomer： solvent ratio is 1：2, the product has the best kinetic hydrate inhibitor performance on THF hydrate. On these bases, the scale-up production of this combined hydrate inhibitor was carried out. Although the scale-up product （HY-10） performs less effectively on the THF hydrate inhibition than HY-1, it functions better than a commercial product （Inhibex501） during in-house tests. HY-10 was successfully applied to the gas production process. Field trials in northem Shaanxi PetroChina Changqing Oilfield Company （PCOC） show that 2 wt% of HY-10 is effective on natural gas hydrate inhibition. It is found through economic analysis that the use of HY-10 has obvious economi- cal advantage over methanol and Inhibex501.
基金Acknowledgements This work was supported by the National Basic Research Program of China （973 Program, No. 2011CB302103）, National Natural Science Foundation of China （Nos. 11274308 and 21401202）, the Hundred Talent Program of the Chinese Academy of Sciences, and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘Si hybrid solar cells have attracted tremendous research attention in recent years because of their low production costs and high performance. However, flexible Si hybrid solar cells have rarely been reported owing to the difficulty of fabricating single-crystalline Si with good flexibility. In this study, we fabricated flexible Si/PEDOT：PSS hybrid solar cells with micro-pyramid-structured Si light absorbers using a facile approach. Compared with planar flexible hybrid solar cells with a power-conversion efficiency of 4%, solar cells with micro-pyramid-structured Si light absorbers have a higher efficiency of 6.3%. External quantum efficiency and electrochemical impedance spectroscopy measurements revealed that the solar cells with micro-pyramid-structured Si light absorbers exhibited a pronounced light-harvesting enhancement in the spectra region of 400-1,000 nm and had a smaller series resistance and larger recombination resistance compared with the planar cells, yielding a higher efficiency. Additionally, in mechanical-bending tests, the flexible solar cells with micro-pyramid-structured Si light absorbers exhibited an excellent performance stability after bending for 600 cycles. Our findings lay the foundation for the real-world applications of flexible Si/PEDOT：PSS hybrid solar cells in next-generation portable electronics.
