Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chl...Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chlorophyll content detection.However,the model developed on one batch or variety cannot produce the same effect for another due to variations,such as samples and measurement conditions.展开更多
To explore the mechanism of the wrinkle formation in graphene on transition metal substrate,a molecular dynamics(MD)simulation package that allows us to simulate systems of millions of atoms was developed.Via the MD s...To explore the mechanism of the wrinkle formation in graphene on transition metal substrate,a molecular dynamics(MD)simulation package that allows us to simulate systems of millions of atoms was developed.Via the MD simulation,we reveal the detailed kinetics of wrinkles formation on a Cu substrate under compressive strain,from nucleation to one-dimensional propagation and then the splitting of a large wrinkle to a few smaller ones,which is in good conformity with experimental observation.Further study reveals that both friction and the adhesion between graphene and Cu substrate are critical for the wrinkle formation and wrinkles can be easily formed with a lower frictional force and/or a smaller adhesion.Finally,we have shown that impurities in graphene or substrates can greatly facilitate the nucleation of wrinkles.The systematic exploration of the wrinkle formation in graphene on a substrate is expected to facilitate the experimental designs for the controllable synthesis of high-quality graphene.展开更多
The Buckingham expansion is important for understanding molecular multipoles and(hyper)polarizabilities.In this study,we give a complete derivation of the Buckingham expansion in the traced form using successive Taylo...The Buckingham expansion is important for understanding molecular multipoles and(hyper)polarizabilities.In this study,we give a complete derivation of the Buckingham expansion in the traced form using successive Taylor series.Based on the derivation results,a general Buckingham expansion in the traced form is proposed,from which highly accurate numerical calculations using the finite field method can be achieved.The transformations from the traced multipoles and multipole-multipole polarizabilities to the corresponding traceless counterparts are realized with an auxiliary traced electric field gradient.The applications of thefinite field method in this study show good agreements with previous theoretical calculations and experimental measurements.展开更多
Protic organic ionic plastic crystals(POIPCs)are promising solid-state proton conductor materials in anhydrous proton exchange membrane fuel cells,due to their mechanical flexibility and high ionic conductivity in the...Protic organic ionic plastic crystals(POIPCs)are promising solid-state proton conductor materials in anhydrous proton exchange membrane fuel cells,due to their mechanical flexibility and high ionic conductivity in the plastic crystal phase.In typical POIPCs,the ions are orientationally disordered while the centers of mass are ordered(positional order)like the crystal phase.The local disorder provides more degrees of freedom for the translational and rotational diffusion of ions,thus enhancing proton conduction either via the vehicle mechanism or the Grotthuss mechanism.Yet the local dynamics and the interactions of the cations and anions during the proton transfer process are far from being fully understood.Here,we performed Car–Parrinello molecular dynamics(CPMD)simulation on the imidazolium methanesulfate([ImH][CH_(3)SO_(3)])unit cell.By artificially creating one proton hole,we found that a proton can hop directly between the cations.Though the anion is not directly involved in proton hopping,the oxygen atom in the sulfonate group interacts with the proton and has a synergetic motion along with the proton hopping process.This indicates the structural disorder of imidazolium rings and the aid of an anion can facilitate Grotthuss-type proton hopping in imidazolium-based POIPCs.展开更多
基金This research was supported by XPCC Science and Technol-ogy Projects of Key Areas(2020AB005).
文摘Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chlorophyll content detection.However,the model developed on one batch or variety cannot produce the same effect for another due to variations,such as samples and measurement conditions.
基金This work was supported by the Institute for Basic Science of South Korea[IBS-R019-D1].
文摘To explore the mechanism of the wrinkle formation in graphene on transition metal substrate,a molecular dynamics(MD)simulation package that allows us to simulate systems of millions of atoms was developed.Via the MD simulation,we reveal the detailed kinetics of wrinkles formation on a Cu substrate under compressive strain,from nucleation to one-dimensional propagation and then the splitting of a large wrinkle to a few smaller ones,which is in good conformity with experimental observation.Further study reveals that both friction and the adhesion between graphene and Cu substrate are critical for the wrinkle formation and wrinkles can be easily formed with a lower frictional force and/or a smaller adhesion.Finally,we have shown that impurities in graphene or substrates can greatly facilitate the nucleation of wrinkles.The systematic exploration of the wrinkle formation in graphene on a substrate is expected to facilitate the experimental designs for the controllable synthesis of high-quality graphene.
基金the National Natural Science Foundation of China(Grant Nos.21573112 and 21421001)。
文摘The Buckingham expansion is important for understanding molecular multipoles and(hyper)polarizabilities.In this study,we give a complete derivation of the Buckingham expansion in the traced form using successive Taylor series.Based on the derivation results,a general Buckingham expansion in the traced form is proposed,from which highly accurate numerical calculations using the finite field method can be achieved.The transformations from the traced multipoles and multipole-multipole polarizabilities to the corresponding traceless counterparts are realized with an auxiliary traced electric field gradient.The applications of thefinite field method in this study show good agreements with previous theoretical calculations and experimental measurements.
基金financially supported by the National Natural Science Foundation of China(No.21573112,No.21703106 and No.21776120)funding from the starting grant(‘One Hundred Talent Program’)from Sichuan University(project No.:YJ202089)the Innovative Teaching Reform Project for Postgraduate Education of Sichuan University(project No.:GSALK2020009)。
文摘Protic organic ionic plastic crystals(POIPCs)are promising solid-state proton conductor materials in anhydrous proton exchange membrane fuel cells,due to their mechanical flexibility and high ionic conductivity in the plastic crystal phase.In typical POIPCs,the ions are orientationally disordered while the centers of mass are ordered(positional order)like the crystal phase.The local disorder provides more degrees of freedom for the translational and rotational diffusion of ions,thus enhancing proton conduction either via the vehicle mechanism or the Grotthuss mechanism.Yet the local dynamics and the interactions of the cations and anions during the proton transfer process are far from being fully understood.Here,we performed Car–Parrinello molecular dynamics(CPMD)simulation on the imidazolium methanesulfate([ImH][CH_(3)SO_(3)])unit cell.By artificially creating one proton hole,we found that a proton can hop directly between the cations.Though the anion is not directly involved in proton hopping,the oxygen atom in the sulfonate group interacts with the proton and has a synergetic motion along with the proton hopping process.This indicates the structural disorder of imidazolium rings and the aid of an anion can facilitate Grotthuss-type proton hopping in imidazolium-based POIPCs.
