The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vi...The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vicinal coupling constants calculated from the torsional angles H（1）-C（1）-C（2）-H（2） in modeling models by means of Karplus equation and observed by decoupling technique. The crystal structure of cis-4-nitro-N-（7-oxabicyclo[4.1.0]hept-2-yl）benzamide further confirms this assignment.展开更多
The structure of liquid water is primarily composed of three-dimensional networks of water clusters formed by hydrogen bonds,and dis-solved oxygen is one of the most important indicators for assessing water qual-ity.I...The structure of liquid water is primarily composed of three-dimensional networks of water clusters formed by hydrogen bonds,and dis-solved oxygen is one of the most important indicators for assessing water qual-ity.In this work,distilled water with different concentration of dissolved oxygen were prepared,and a clear negative correlation between the size of water clus-ters and dissolved oxygen concentration was observed.Besides,a phenomenon of rapid absorption and release of oxygen at the water interfaces was unveiled,suggesting that oxygen molecules predominantly exist at the interfaces of water clusters.Oxygen molecules can move rapidly through the interfaces among water clusters,allowing dissolved oxygen to quickly reach a saturation level at certain partial pressure of oxygen and temperature.Further exploration into the mechanism by molecular dynamics simulations of oxygen and water clusters found that oxygen molecules can only exist stably at the interfaces among water clusters.A semi-empirical formula relating the average number of water molecules in a cluster(n)to ^(17)O NMR half-peak width(W)was summarized:n=0.1 W+0.85.These findings provide a foundation for exploring the structure and properties of water.展开更多
We study the ground-state properties of the _(YY)^(6)He double hyperon for _(ΛΛ)^(6)He and _(ΩΩ)^(6)He nuclei in a threebody model(Y+Y+α).We solve two coupled Faddeev equations corresponding to the three-body con...We study the ground-state properties of the _(YY)^(6)He double hyperon for _(ΛΛ)^(6)He and _(ΩΩ)^(6)He nuclei in a threebody model(Y+Y+α).We solve two coupled Faddeev equations corresponding to the three-body configurations(αY,Y)and(YY,α)in configuration space with the hyperspherical harmonics expansion method by employing the most recent hyperon-hyperon interactions obtained from lattice QCD simulations.Our numerical analysis for _(ΛΛ)^(6)He,using threeΛΛlattice interaction models,leads to a ground state binding energy in the(-7.468,-7.804)MeV domain and the separations <r_(Λ-Λ)>and <r_(α-Λ)>in the domains of(3.555,3.629)fm and(2.867,2.902)fm,respectively.The binding energy of the double-Ω hypenucleus _(ΩΩ)^(6)He leads to -67.21 MeV and consequently to smaller separations <r_(Ω-Ω)>=1.521 fm and <r_(α-Ω)>=1.293 fm.In addition to geometrical properties,we study the structure of ground-state wave functions and show that the main contributions are from the s-wave channels.Our results are consistent with the existing theoretical and experimental data.展开更多
文摘The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vicinal coupling constants calculated from the torsional angles H（1）-C（1）-C（2）-H（2） in modeling models by means of Karplus equation and observed by decoupling technique. The crystal structure of cis-4-nitro-N-（7-oxabicyclo[4.1.0]hept-2-yl）benzamide further confirms this assignment.
基金funding support from National Natural Science Foundation of China(Project No.61574091)Wuxi River and Lake Management and Water Resources Management Center(Project No.JSXXCG2022-004).
文摘The structure of liquid water is primarily composed of three-dimensional networks of water clusters formed by hydrogen bonds,and dis-solved oxygen is one of the most important indicators for assessing water qual-ity.In this work,distilled water with different concentration of dissolved oxygen were prepared,and a clear negative correlation between the size of water clus-ters and dissolved oxygen concentration was observed.Besides,a phenomenon of rapid absorption and release of oxygen at the water interfaces was unveiled,suggesting that oxygen molecules predominantly exist at the interfaces of water clusters.Oxygen molecules can move rapidly through the interfaces among water clusters,allowing dissolved oxygen to quickly reach a saturation level at certain partial pressure of oxygen and temperature.Further exploration into the mechanism by molecular dynamics simulations of oxygen and water clusters found that oxygen molecules can only exist stably at the interfaces among water clusters.A semi-empirical formula relating the average number of water molecules in a cluster(n)to ^(17)O NMR half-peak width(W)was summarized:n=0.1 W+0.85.These findings provide a foundation for exploring the structure and properties of water.
基金Supported by the National Science Foundation under Grant No.NSF-PHY-2000029 with Central State University。
文摘We study the ground-state properties of the _(YY)^(6)He double hyperon for _(ΛΛ)^(6)He and _(ΩΩ)^(6)He nuclei in a threebody model(Y+Y+α).We solve two coupled Faddeev equations corresponding to the three-body configurations(αY,Y)and(YY,α)in configuration space with the hyperspherical harmonics expansion method by employing the most recent hyperon-hyperon interactions obtained from lattice QCD simulations.Our numerical analysis for _(ΛΛ)^(6)He,using threeΛΛlattice interaction models,leads to a ground state binding energy in the(-7.468,-7.804)MeV domain and the separations <r_(Λ-Λ)>and <r_(α-Λ)>in the domains of(3.555,3.629)fm and(2.867,2.902)fm,respectively.The binding energy of the double-Ω hypenucleus _(ΩΩ)^(6)He leads to -67.21 MeV and consequently to smaller separations <r_(Ω-Ω)>=1.521 fm and <r_(α-Ω)>=1.293 fm.In addition to geometrical properties,we study the structure of ground-state wave functions and show that the main contributions are from the s-wave channels.Our results are consistent with the existing theoretical and experimental data.
