6 Atomic fragment types of organic compound have been defined, and the multilevel atom-pair frequency matrix has been constructed according to the occurrence number in pairs of atomic fragments with different bond len...6 Atomic fragment types of organic compound have been defined, and the multilevel atom-pair frequency matrix has been constructed according to the occurrence number in pairs of atomic fragments with different bond lengths in the molecule. On the basis of them, a novel molecular coding technique： characteristic atom-pair holographic code （CAHC）, is obtained. To some extent, this method exhibits a large number of benefits at the same time. For example, it can calculate 2D molecular topological descriptor easily, operate without difficulty and possess definite physicochemical meaning of 3D molecular structural characterization methods, and may fetch the complicated information of molecule, etc. Therefore, it is appropriate for the study on quantitative structure-property/activity relationship （QSPR/QSAR） of medicines and biological molecules. We attempt in this paper to utilize the method of CAHC to the quantitative prediction of reversed-phase liquid chromatogram （RPLC） retention data of 33 purine derivatives and 24 steroids. The fitting multiple correlation coefficient R2, cross-validated multiple correlation coefficient Q2 and predicted ability Q^2 pred over test set＇s samples of obtained partial least-square （PLS） regression model are respectively 0.990, 0.893 and 0.977, 0.897, 0.941.展开更多
The quantum effect of nonlinear co-tunnelling process, which is dependent on atom-pair tunneling and asymmetry of an double-well trap, is studied by using an asymmetrical extended Bose–Hubbard model. Due to the exist...The quantum effect of nonlinear co-tunnelling process, which is dependent on atom-pair tunneling and asymmetry of an double-well trap, is studied by using an asymmetrical extended Bose–Hubbard model. Due to the existence of atompair tunneling that describes quantum phenomena of ultracold atom-gas clouds in an asymmetrical double-well trap, the asymmetrical extended Bose–Hubbard model is better than the previous Bose–Hubbard model model by comparing with the experimental data cited from the literature. The dependence of dynamics and quantum phase transition on atom-pair tunneling and asymmetry are investigated. Importantly, it shows that the asymmetry of the extended Bose–Hubbard model,corresponding to the bias between double wells, leads to a number of resonance tunneling processes, which tunneling is renamed conditional resonance tunneling, and corrects the atom-number parity effect by controlling the bias between double wells.展开更多
As the definitions of 36 atomic fragment types in organic compounds,multi-order atom-pair frequency matrix was constructed in terms of atomic fragments occurring in pair at different bond distances,and based on a new ...As the definitions of 36 atomic fragment types in organic compounds,multi-order atom-pair frequency matrix was constructed in terms of atomic fragments occurring in pair at different bond distances,and based on a new molecular coding technique as characteristic atom-pair hologram code(CAHC)proposed in this paper.Collected from reference reports,a large-scale ion mobility spectrometry collision cross section database comprising 819 samples was established and quantitative structure-spectrometry relationship(QSSR)studies were performed with the CAHC.Testing modeling stabilities and generalization abilities by both internal and external examinations confirmed that CAHC was in obvious linear relationship with peptide collision cross sections,while it was involved in partially nonlinear factors for a few polypeptides.The model was deemed to assist in quantitative computer-aided predictions for peptide collision cross sections.展开更多
基金This work was supported by the State Key Laboratory of Chemo/Biosensing and Chemometrics Foundation (No. 05-12-1), Fok-Yingtung Educational Foundation (No. 98-7-6) and Chongqing University Innovation Foundation of Science and Technology ( No. 06-1-1)
文摘6 Atomic fragment types of organic compound have been defined, and the multilevel atom-pair frequency matrix has been constructed according to the occurrence number in pairs of atomic fragments with different bond lengths in the molecule. On the basis of them, a novel molecular coding technique： characteristic atom-pair holographic code （CAHC）, is obtained. To some extent, this method exhibits a large number of benefits at the same time. For example, it can calculate 2D molecular topological descriptor easily, operate without difficulty and possess definite physicochemical meaning of 3D molecular structural characterization methods, and may fetch the complicated information of molecule, etc. Therefore, it is appropriate for the study on quantitative structure-property/activity relationship （QSPR/QSAR） of medicines and biological molecules. We attempt in this paper to utilize the method of CAHC to the quantitative prediction of reversed-phase liquid chromatogram （RPLC） retention data of 33 purine derivatives and 24 steroids. The fitting multiple correlation coefficient R2, cross-validated multiple correlation coefficient Q2 and predicted ability Q^2 pred over test set＇s samples of obtained partial least-square （PLS） regression model are respectively 0.990, 0.893 and 0.977, 0.897, 0.941.
基金Project supported by the National Natural Science Foundation of China(Grant No.11075099)
文摘The quantum effect of nonlinear co-tunnelling process, which is dependent on atom-pair tunneling and asymmetry of an double-well trap, is studied by using an asymmetrical extended Bose–Hubbard model. Due to the existence of atompair tunneling that describes quantum phenomena of ultracold atom-gas clouds in an asymmetrical double-well trap, the asymmetrical extended Bose–Hubbard model is better than the previous Bose–Hubbard model model by comparing with the experimental data cited from the literature. The dependence of dynamics and quantum phase transition on atom-pair tunneling and asymmetry are investigated. Importantly, it shows that the asymmetry of the extended Bose–Hubbard model,corresponding to the bias between double wells, leads to a number of resonance tunneling processes, which tunneling is renamed conditional resonance tunneling, and corrects the atom-number parity effect by controlling the bias between double wells.
文摘As the definitions of 36 atomic fragment types in organic compounds,multi-order atom-pair frequency matrix was constructed in terms of atomic fragments occurring in pair at different bond distances,and based on a new molecular coding technique as characteristic atom-pair hologram code(CAHC)proposed in this paper.Collected from reference reports,a large-scale ion mobility spectrometry collision cross section database comprising 819 samples was established and quantitative structure-spectrometry relationship(QSSR)studies were performed with the CAHC.Testing modeling stabilities and generalization abilities by both internal and external examinations confirmed that CAHC was in obvious linear relationship with peptide collision cross sections,while it was involved in partially nonlinear factors for a few polypeptides.The model was deemed to assist in quantitative computer-aided predictions for peptide collision cross sections.
