Reversible data hiding(RDH)is a method to embed messages into an image that human eyes are difficult to recognize the differences between the original image and the embedded image.The method needs to make sure that th...Reversible data hiding(RDH)is a method to embed messages into an image that human eyes are difficult to recognize the differences between the original image and the embedded image.The method needs to make sure that the original image and the embedded information can be exactly recovered.The prediction-error expansion(PEE)is a successful way to realize RDH.However,it is fixed when pairing the conventional twodimensional prediction-error histogram(2D-PEH).So,the embedding capacity(EC)and embedding distortion(ED)are not satisfactory.In this study,we propose a method called greedy pairing prediction-error expansion(GPPEE)based on pairwise RDH and demonstrate GPPEE can achieve a more efficient embedding goal and reduce ED.展开更多
The four nucleic acid DNA bases（adenine, thymine, guanine, cytosine） and ten cis Watson-Crick/Watson-Crick（cis WC/WC） DNA base pairs were investigated by density functional theory（DFT） quantum chemical calculati...The four nucleic acid DNA bases（adenine, thymine, guanine, cytosine） and ten cis Watson-Crick/Watson-Crick（cis WC/WC） DNA base pairs were investigated by density functional theory（DFT） quantum chemical calculations. Geometry optimizations were carried out on the four bases and ten base pairs at the B3LYP level with 6-31G^（＊＊） basis set. All the optimizations were performed within Cs symmetry. The optimum structures for the four bases and seven cis WC/WC base pairs were obtained, and Natural Bond Orbital analysis（NBO） was based on these structures. The possibilities of matches between any two of the four bases through their Watson-Crick（WC） edges were discussed. The structures of seven cis WC/WC base pairs change to a certain extent relative to these of the four bases due to the formation of hydrogen bonds. These base pairs existing in DNA have an important influence on the structural stability of the double helix. The analysis of the electronic structures and molecular orbitals for seven cis WC/WC base pairs can provide significant information about the relationship between charge transfer along the hydrogen bond and the Frontier orbitals of these base pairs.展开更多
Based on Maxwell’s constraint counting theory, rigidity percolation in GexSe1-x glasses occurs when the mean coordination number reaches the value of 2.4. This corresponds to Ge0.20Se0.80 glass. At this composition, ...Based on Maxwell’s constraint counting theory, rigidity percolation in GexSe1-x glasses occurs when the mean coordination number reaches the value of 2.4. This corresponds to Ge0.20Se0.80 glass. At this composition, the number of constraints experienced by an atom equals the number of degrees of freedom in three dimensions. Hence, at this composition, the network changes from a floppy phase to a rigid phase, and rigidity starts to percolate. In this work, we use reverse Monte Carlo (RMC) modeling to model the structure of Ge0.20Se0.80 glass by simulating its experimental total atomic pair distribution function (PDF) obtained via high energy synchrotron radiation. A three-dimensional configuration of 2836 atoms was obtained, from which we extracted the partial atomic pair distribution functions associated with Ge-Ge, Ge-Se and Se-Se real space correlations that are hard to extract experimentally from total scattering methods. Bond angle distributions, coordination numbers, mean coordination numbers and the number of floppy modes were also extracted and discussed. More structural insights about network topology at this composition were illustrated. The results indicate that in Ge0.20Se0.80 glass, Ge atoms break up and cross-link the Se chain structure, and form structural units that are four-fold coordinated (the GeSe4 tetrahedra). These tetrahedra form the basic building block and are connected via shared Se atoms or short Se chains. The extent of the intermediate ranged oscillations in real space (as extracted from the width of the first sharp diffraction peak) was found to be around 19.6 ?. The bonding schemes in this glass are consistent with the so-called “8-N” rule and can be interpreted in terms of a chemically ordered network model.展开更多
Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chrom...Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chromatography with indirect UV detection or conductivity展开更多
基金supported by MOST under Grants No.107-2221-E-845-002-MY3 and No.110-2221-E-845-002-。
文摘Reversible data hiding(RDH)is a method to embed messages into an image that human eyes are difficult to recognize the differences between the original image and the embedded image.The method needs to make sure that the original image and the embedded information can be exactly recovered.The prediction-error expansion(PEE)is a successful way to realize RDH.However,it is fixed when pairing the conventional twodimensional prediction-error histogram(2D-PEH).So,the embedding capacity(EC)and embedding distortion(ED)are not satisfactory.In this study,we propose a method called greedy pairing prediction-error expansion(GPPEE)based on pairwise RDH and demonstrate GPPEE can achieve a more efficient embedding goal and reduce ED.
基金Project supported by the National Key Research and Development Project(No.2016YFB0201404)
文摘The four nucleic acid DNA bases（adenine, thymine, guanine, cytosine） and ten cis Watson-Crick/Watson-Crick（cis WC/WC） DNA base pairs were investigated by density functional theory（DFT） quantum chemical calculations. Geometry optimizations were carried out on the four bases and ten base pairs at the B3LYP level with 6-31G^（＊＊） basis set. All the optimizations were performed within Cs symmetry. The optimum structures for the four bases and seven cis WC/WC base pairs were obtained, and Natural Bond Orbital analysis（NBO） was based on these structures. The possibilities of matches between any two of the four bases through their Watson-Crick（WC） edges were discussed. The structures of seven cis WC/WC base pairs change to a certain extent relative to these of the four bases due to the formation of hydrogen bonds. These base pairs existing in DNA have an important influence on the structural stability of the double helix. The analysis of the electronic structures and molecular orbitals for seven cis WC/WC base pairs can provide significant information about the relationship between charge transfer along the hydrogen bond and the Frontier orbitals of these base pairs.
文摘Based on Maxwell’s constraint counting theory, rigidity percolation in GexSe1-x glasses occurs when the mean coordination number reaches the value of 2.4. This corresponds to Ge0.20Se0.80 glass. At this composition, the number of constraints experienced by an atom equals the number of degrees of freedom in three dimensions. Hence, at this composition, the network changes from a floppy phase to a rigid phase, and rigidity starts to percolate. In this work, we use reverse Monte Carlo (RMC) modeling to model the structure of Ge0.20Se0.80 glass by simulating its experimental total atomic pair distribution function (PDF) obtained via high energy synchrotron radiation. A three-dimensional configuration of 2836 atoms was obtained, from which we extracted the partial atomic pair distribution functions associated with Ge-Ge, Ge-Se and Se-Se real space correlations that are hard to extract experimentally from total scattering methods. Bond angle distributions, coordination numbers, mean coordination numbers and the number of floppy modes were also extracted and discussed. More structural insights about network topology at this composition were illustrated. The results indicate that in Ge0.20Se0.80 glass, Ge atoms break up and cross-link the Se chain structure, and form structural units that are four-fold coordinated (the GeSe4 tetrahedra). These tetrahedra form the basic building block and are connected via shared Se atoms or short Se chains. The extent of the intermediate ranged oscillations in real space (as extracted from the width of the first sharp diffraction peak) was found to be around 19.6 ?. The bonding schemes in this glass are consistent with the so-called “8-N” rule and can be interpreted in terms of a chemically ordered network model.
文摘Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chromatography with indirect UV detection or conductivity
