Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an ...Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.展开更多
In the framework of the left-right twin Higgs （LRTH） model, we study the possibilities to detect the new Z＇ boson at the Tevatron and LHC. First, using pp collision data collected by the DO and CDF II detectors, we...In the framework of the left-right twin Higgs （LRTH） model, we study the possibilities to detect the new Z＇ boson at the Tevatron and LHC. First, using pp collision data collected by the DO and CDF II detectors, we find that the LRTH Z＇ boson is excluded with masses below 940 GeV. Then we search for signatures of the Z＇ boson at the LHC from the analysis of some distributions for pp --＊ It＋g- ＋ X, such as the number of events, the differential cross section of the dimuon invariant mass, the distributions of the transverse momentum and the forward-backward charge asymmetry. We do our calculation for two typical values of the LHC center of mass energy （7 and 14 TeV）. The numerical results show that, by applying convenient cuts on some of the observables, the dimuon invariant mass and final particle PT distributions can reveal the presence of the heavy neutral gauge boson Z＇ contribution in the LRTH model.展开更多
文摘Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.
基金supported by the National Natural Science Foundation of China(Grant No.11147193)
文摘In the framework of the left-right twin Higgs （LRTH） model, we study the possibilities to detect the new Z＇ boson at the Tevatron and LHC. First, using pp collision data collected by the DO and CDF II detectors, we find that the LRTH Z＇ boson is excluded with masses below 940 GeV. Then we search for signatures of the Z＇ boson at the LHC from the analysis of some distributions for pp --＊ It＋g- ＋ X, such as the number of events, the differential cross section of the dimuon invariant mass, the distributions of the transverse momentum and the forward-backward charge asymmetry. We do our calculation for two typical values of the LHC center of mass energy （7 and 14 TeV）. The numerical results show that, by applying convenient cuts on some of the observables, the dimuon invariant mass and final particle PT distributions can reveal the presence of the heavy neutral gauge boson Z＇ contribution in the LRTH model.
