The Fe-Ti binary system was re-assessed using the CALPHAD method in order to improve the capability of being extrapolated to a ternary or higher-order system. Compared with previous assessments, the main focus was put...The Fe-Ti binary system was re-assessed using the CALPHAD method in order to improve the capability of being extrapolated to a ternary or higher-order system. Compared with previous assessments, the main focus was put on the thermodynamic description of the two intermetallic compounds Fe2Ti and FeTi. The C14_Laves phase Fe2Ti was described by the two-sublattice model, which is widely used at present. By checking the homogeneity range on the boundary of the ternary systems involving the binary, the phase boundary of this compound was further confirmed. The FeTi phase with a BCC_B2 crystal structure was treated as the ordered phase of the BCC_A2 phase and a unified Gibbs energy function was used to describe both the ordered and disordered phases. Reproduction of the specific heat capacities of these compounds was another aspect paid particular attention to. Comprehensive comparisons of the calculated and experimental results regarding the phase diagram and thermodynamic properties show a good agreement between them and prove the validity of the present thermodynamic description.展开更多
For investigating dynamic evolution of a mass-varying harmonic oscillator we constitute a ket-bra integrationoperator in coherent state representation and then perform this integral by virtue of the technique of integ...For investigating dynamic evolution of a mass-varying harmonic oscillator we constitute a ket-bra integrationoperator in coherent state representation and then perform this integral by virtue of the technique of integration withinan ordered product of operators.The normally ordered time evolution operator is thus obtained.We then derive theWigner function of u(t)|n>,where |n> is a Fock state,which exhibits a generalized squeezing,the squeezing effect isrelated to the varying mass with time.展开更多
Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopor...Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopore channels, aiming to efficiently and conveniently uptake U(VI) from aqueous solution. The resultant material possesses highly ordered mesoporous structure with large surface area, uniform pore size, excellent thermal stability, quick magnetic response, and desirable acids resistance, confirmed by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), N_2 adsorption/desorption experiments, powder X-ray diffraction(PXRD), and thermogravimetric analysis(TGA). Detailed U(VI) sorption test indicated that this material is indeed an effective U(VI) sorbent with fast sorption kinetics of less than 2 h, large sorption capacity of 160 mg/g at p H 5.0±0.1, and desirable selectivity towards U(VI) ions over a range of competing metal ions. The absorbed U(VI) can be easily desorbed by 0.01 mol/L or more concentrated HNO_3 solution, and the reclaimed sorbent can be reused with no obvious decrease of sorption capacity even after 4 sorption-desorption cycles. The present results suggest the vast opportunities of this kind of magnetic composite on the solid-phase extraction of U(VI).展开更多
基金Project (IP08-092009) supported by Sino Swiss Science and Technology Cooperation (SSSTC)Project (50971136) supported by the National Natural Science Foundation of ChinaProject (1343-71134001013) supported by the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education of China
文摘The Fe-Ti binary system was re-assessed using the CALPHAD method in order to improve the capability of being extrapolated to a ternary or higher-order system. Compared with previous assessments, the main focus was put on the thermodynamic description of the two intermetallic compounds Fe2Ti and FeTi. The C14_Laves phase Fe2Ti was described by the two-sublattice model, which is widely used at present. By checking the homogeneity range on the boundary of the ternary systems involving the binary, the phase boundary of this compound was further confirmed. The FeTi phase with a BCC_B2 crystal structure was treated as the ordered phase of the BCC_A2 phase and a unified Gibbs energy function was used to describe both the ordered and disordered phases. Reproduction of the specific heat capacities of these compounds was another aspect paid particular attention to. Comprehensive comparisons of the calculated and experimental results regarding the phase diagram and thermodynamic properties show a good agreement between them and prove the validity of the present thermodynamic description.
基金Supported by National Natural Science Foundation of China under Grant No.10874174
文摘For investigating dynamic evolution of a mass-varying harmonic oscillator we constitute a ket-bra integrationoperator in coherent state representation and then perform this integral by virtue of the technique of integration withinan ordered product of operators.The normally ordered time evolution operator is thus obtained.We then derive theWigner function of u(t)|n>,where |n> is a Fock state,which exhibits a generalized squeezing,the squeezing effect isrelated to the varying mass with time.
基金supported by the National Natural Science Foundation of China (11275219, 11275090, U1432103)the “Strategic Priority Research program” of the Chinese Academy of Sciences (XDA030104)+1 种基金the State Key Laboratory of NBC Protection for Civilian (SKLNB201412)the Scientific Research Fund of Hunan Provincial Education Department (12A116)
文摘Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopore channels, aiming to efficiently and conveniently uptake U(VI) from aqueous solution. The resultant material possesses highly ordered mesoporous structure with large surface area, uniform pore size, excellent thermal stability, quick magnetic response, and desirable acids resistance, confirmed by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), N_2 adsorption/desorption experiments, powder X-ray diffraction(PXRD), and thermogravimetric analysis(TGA). Detailed U(VI) sorption test indicated that this material is indeed an effective U(VI) sorbent with fast sorption kinetics of less than 2 h, large sorption capacity of 160 mg/g at p H 5.0±0.1, and desirable selectivity towards U(VI) ions over a range of competing metal ions. The absorbed U(VI) can be easily desorbed by 0.01 mol/L or more concentrated HNO_3 solution, and the reclaimed sorbent can be reused with no obvious decrease of sorption capacity even after 4 sorption-desorption cycles. The present results suggest the vast opportunities of this kind of magnetic composite on the solid-phase extraction of U(VI).
