The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric ...The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric technique.The experimental isomeric yield ratio(IR) was determined for the reaction products ^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax) range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax)) and the IR for the isomeric pair ^(95m,g)Nb from the ^(nat)Mo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times) in the experimental IR relative to all theoretical estimates.展开更多
Molecular sieves of SAPO-41 with different silicon contents were synthesized and characterized by XRD,N2 adsorption,XRF,pyridine-IR and 29SiMAS-NMR.The isomerization properties of the SAPO-41 were investigated by usin...Molecular sieves of SAPO-41 with different silicon contents were synthesized and characterized by XRD,N2 adsorption,XRF,pyridine-IR and 29SiMAS-NMR.The isomerization properties of the SAPO-41 were investigated by using m-xylene as a feedstock.The SAPO-41 obtained from the synthesis gel with SiO2/Al2O3=0.3 showed the highest activity to the isomerization of m-xylene and the largest number of Brnsted acid sites was also observed with Py-IR over this sample.The state of Si in the framework of SAPO-41 plays a predominant role on the Brnsted acidity.The relationship between the activity and the acidity obtained in this study can be explained in terms of the distribution of stronger Brnsted acid sites.展开更多
文摘The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric technique.The experimental isomeric yield ratio(IR) was determined for the reaction products ^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax) range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax)) and the IR for the isomeric pair ^(95m,g)Nb from the ^(nat)Mo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times) in the experimental IR relative to all theoretical estimates.
文摘Molecular sieves of SAPO-41 with different silicon contents were synthesized and characterized by XRD,N2 adsorption,XRF,pyridine-IR and 29SiMAS-NMR.The isomerization properties of the SAPO-41 were investigated by using m-xylene as a feedstock.The SAPO-41 obtained from the synthesis gel with SiO2/Al2O3=0.3 showed the highest activity to the isomerization of m-xylene and the largest number of Brnsted acid sites was also observed with Py-IR over this sample.The state of Si in the framework of SAPO-41 plays a predominant role on the Brnsted acidity.The relationship between the activity and the acidity obtained in this study can be explained in terms of the distribution of stronger Brnsted acid sites.
