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Lixia Ling - One of the best experts on this subject based on the ideXlab platform.

  • fundamental studies about the interaction of water with perfect oxygen vacancy and pre covered oxygen cu2o 1 1 1 Surfaces thermochemistry barrier product
    Applied Surface Science, 2013
    Co-Authors: Riguang Zhang, Baojun Wang, Lixia Ling
    Abstract:

    Abstract The adsorption and dissociation of H 2 O on three types of Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and pre-covered oxygen Surfaces have been systematically investigated using periodic density functional slab model calculations. Different kinds of possible modes of H 2 O adsorbed on those Surfaces are identified. Our results first show that the bonding of dissociated species (HO, H and O) for H 2 O is substantially stronger than that of H 2 O on Cu 2 O(1 1 1) Surface. Then, on perfect Surface, H 2 O mainly exist in the form of molecular adsorption, in which Cu CUS site is chemisorption, O SUF site is physisorption with a weak hydrogen bond. On oxygen-vacancy Surface, dissociative adsorption of H 2 O occurs predominantly, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward H 2 O dissociation; meanwhile, a small quantity of chemisorption H 2 O adsorbed at Cu CUS site also exists. On pre-covered oxygen Surface, H 2 O is typical of physisorption due to a hydrogen bond interaction between H of adsorbed H 2 O and pre-covered oxygen. Further, the dissociation mechanisms of molecular adsorption H 2 O, OH from dissociative adsorption H 2 O, as well as single OH group on different Surfaces, leading to the final products H and O atoms, give out the thermochemistry, barrier of each elementary reaction, which indicates that OH species is energetically the most stable product on those Surfaces. Pre-covered oxygen on Cu 2 O(1 1 1) Surface can act as a promoter to facilitate the first dehydrogenation of molecular adsorption H 2 O leading to OH species, which is more favorable both thermodynamically and kinetically than that of molecular adsorption H 2 O on other two Surfaces. Finally, the vibrational frequencies for the adsorbed H 2 O and OH species on Cu 2 O(1 1 1) Surfaces can be applied to Guide Surface vibrational spectroscopy in experiment. Our calculation may be a worthwhile theoretical example for the interaction of H 2 O with other metal oxide Surface.

  • a mechanistic study of h2s adsorption and dissociation on cu2o 1 1 1 Surfaces thermochemistry reaction barrier
    Applied Surface Science, 2012
    Co-Authors: Riguang Zhang, Hongyan Liu, Lixia Ling, Baojun Wang
    Abstract:

    Abstract The interaction mechanism of H 2 S with different Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and sulfur-containing Surfaces, have been systematically studied using periodic density functional calculations. Different kinds of possible modes of H 2 S, as well as the resultant SH and S species adsorbed on these Surfaces are identified. Two types of pathways via molecular and dissociative adsorption processes are mapped out. Our results show that sulfur species (H 2 S, SH and S) interact with Surface Cu centers; H 2 S exists in the form of molecular adsorption on perfect and sulfur-containing Surfaces; the dissociative adsorption of H 2 S occurs predominantly on oxygen-vacancy Surface, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward the dissociation of H 2 S. On the other hand, the dissociation processes of the molecular and dissociative adsorption H 2 S, leading to final product S species on these Cu 2 O(1 1 1) Surfaces, show that the overall dissociation process is exothermic. Meanwhile, with respect to molecular adsorption H 2 S, the activation barrier and reaction energy of the overall dissociation process on perfect and oxygen-vacancy Surfaces indicate that H 2 S can easily dissociate into S species. Importantly, in the case of dissociative adsorption of H 2 S, the dissociation of H 2 S into S species is a spontaneous process with respect to molecular adsorption H 2 S. However, on sulfur-containing Surface, the presence of Surface S atom goes against the H S bond-breaking process both thermodynamically and kinetically. Finally, the vibrational frequencies for the adsorbed H 2 S, SH and S species on these Surfaces have been obtained, which can be applied to Guide Surface vibrational spectroscopy in experiment.

Baojun Wang - One of the best experts on this subject based on the ideXlab platform.

  • fundamental studies about the interaction of water with perfect oxygen vacancy and pre covered oxygen cu2o 1 1 1 Surfaces thermochemistry barrier product
    Applied Surface Science, 2013
    Co-Authors: Riguang Zhang, Baojun Wang, Lixia Ling
    Abstract:

    Abstract The adsorption and dissociation of H 2 O on three types of Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and pre-covered oxygen Surfaces have been systematically investigated using periodic density functional slab model calculations. Different kinds of possible modes of H 2 O adsorbed on those Surfaces are identified. Our results first show that the bonding of dissociated species (HO, H and O) for H 2 O is substantially stronger than that of H 2 O on Cu 2 O(1 1 1) Surface. Then, on perfect Surface, H 2 O mainly exist in the form of molecular adsorption, in which Cu CUS site is chemisorption, O SUF site is physisorption with a weak hydrogen bond. On oxygen-vacancy Surface, dissociative adsorption of H 2 O occurs predominantly, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward H 2 O dissociation; meanwhile, a small quantity of chemisorption H 2 O adsorbed at Cu CUS site also exists. On pre-covered oxygen Surface, H 2 O is typical of physisorption due to a hydrogen bond interaction between H of adsorbed H 2 O and pre-covered oxygen. Further, the dissociation mechanisms of molecular adsorption H 2 O, OH from dissociative adsorption H 2 O, as well as single OH group on different Surfaces, leading to the final products H and O atoms, give out the thermochemistry, barrier of each elementary reaction, which indicates that OH species is energetically the most stable product on those Surfaces. Pre-covered oxygen on Cu 2 O(1 1 1) Surface can act as a promoter to facilitate the first dehydrogenation of molecular adsorption H 2 O leading to OH species, which is more favorable both thermodynamically and kinetically than that of molecular adsorption H 2 O on other two Surfaces. Finally, the vibrational frequencies for the adsorbed H 2 O and OH species on Cu 2 O(1 1 1) Surfaces can be applied to Guide Surface vibrational spectroscopy in experiment. Our calculation may be a worthwhile theoretical example for the interaction of H 2 O with other metal oxide Surface.

  • a mechanistic study of h2s adsorption and dissociation on cu2o 1 1 1 Surfaces thermochemistry reaction barrier
    Applied Surface Science, 2012
    Co-Authors: Riguang Zhang, Hongyan Liu, Lixia Ling, Baojun Wang
    Abstract:

    Abstract The interaction mechanism of H 2 S with different Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and sulfur-containing Surfaces, have been systematically studied using periodic density functional calculations. Different kinds of possible modes of H 2 S, as well as the resultant SH and S species adsorbed on these Surfaces are identified. Two types of pathways via molecular and dissociative adsorption processes are mapped out. Our results show that sulfur species (H 2 S, SH and S) interact with Surface Cu centers; H 2 S exists in the form of molecular adsorption on perfect and sulfur-containing Surfaces; the dissociative adsorption of H 2 S occurs predominantly on oxygen-vacancy Surface, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward the dissociation of H 2 S. On the other hand, the dissociation processes of the molecular and dissociative adsorption H 2 S, leading to final product S species on these Cu 2 O(1 1 1) Surfaces, show that the overall dissociation process is exothermic. Meanwhile, with respect to molecular adsorption H 2 S, the activation barrier and reaction energy of the overall dissociation process on perfect and oxygen-vacancy Surfaces indicate that H 2 S can easily dissociate into S species. Importantly, in the case of dissociative adsorption of H 2 S, the dissociation of H 2 S into S species is a spontaneous process with respect to molecular adsorption H 2 S. However, on sulfur-containing Surface, the presence of Surface S atom goes against the H S bond-breaking process both thermodynamically and kinetically. Finally, the vibrational frequencies for the adsorbed H 2 S, SH and S species on these Surfaces have been obtained, which can be applied to Guide Surface vibrational spectroscopy in experiment.

Riguang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • fundamental studies about the interaction of water with perfect oxygen vacancy and pre covered oxygen cu2o 1 1 1 Surfaces thermochemistry barrier product
    Applied Surface Science, 2013
    Co-Authors: Riguang Zhang, Baojun Wang, Lixia Ling
    Abstract:

    Abstract The adsorption and dissociation of H 2 O on three types of Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and pre-covered oxygen Surfaces have been systematically investigated using periodic density functional slab model calculations. Different kinds of possible modes of H 2 O adsorbed on those Surfaces are identified. Our results first show that the bonding of dissociated species (HO, H and O) for H 2 O is substantially stronger than that of H 2 O on Cu 2 O(1 1 1) Surface. Then, on perfect Surface, H 2 O mainly exist in the form of molecular adsorption, in which Cu CUS site is chemisorption, O SUF site is physisorption with a weak hydrogen bond. On oxygen-vacancy Surface, dissociative adsorption of H 2 O occurs predominantly, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward H 2 O dissociation; meanwhile, a small quantity of chemisorption H 2 O adsorbed at Cu CUS site also exists. On pre-covered oxygen Surface, H 2 O is typical of physisorption due to a hydrogen bond interaction between H of adsorbed H 2 O and pre-covered oxygen. Further, the dissociation mechanisms of molecular adsorption H 2 O, OH from dissociative adsorption H 2 O, as well as single OH group on different Surfaces, leading to the final products H and O atoms, give out the thermochemistry, barrier of each elementary reaction, which indicates that OH species is energetically the most stable product on those Surfaces. Pre-covered oxygen on Cu 2 O(1 1 1) Surface can act as a promoter to facilitate the first dehydrogenation of molecular adsorption H 2 O leading to OH species, which is more favorable both thermodynamically and kinetically than that of molecular adsorption H 2 O on other two Surfaces. Finally, the vibrational frequencies for the adsorbed H 2 O and OH species on Cu 2 O(1 1 1) Surfaces can be applied to Guide Surface vibrational spectroscopy in experiment. Our calculation may be a worthwhile theoretical example for the interaction of H 2 O with other metal oxide Surface.

  • a mechanistic study of h2s adsorption and dissociation on cu2o 1 1 1 Surfaces thermochemistry reaction barrier
    Applied Surface Science, 2012
    Co-Authors: Riguang Zhang, Hongyan Liu, Lixia Ling, Baojun Wang
    Abstract:

    Abstract The interaction mechanism of H 2 S with different Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and sulfur-containing Surfaces, have been systematically studied using periodic density functional calculations. Different kinds of possible modes of H 2 S, as well as the resultant SH and S species adsorbed on these Surfaces are identified. Two types of pathways via molecular and dissociative adsorption processes are mapped out. Our results show that sulfur species (H 2 S, SH and S) interact with Surface Cu centers; H 2 S exists in the form of molecular adsorption on perfect and sulfur-containing Surfaces; the dissociative adsorption of H 2 S occurs predominantly on oxygen-vacancy Surface, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward the dissociation of H 2 S. On the other hand, the dissociation processes of the molecular and dissociative adsorption H 2 S, leading to final product S species on these Cu 2 O(1 1 1) Surfaces, show that the overall dissociation process is exothermic. Meanwhile, with respect to molecular adsorption H 2 S, the activation barrier and reaction energy of the overall dissociation process on perfect and oxygen-vacancy Surfaces indicate that H 2 S can easily dissociate into S species. Importantly, in the case of dissociative adsorption of H 2 S, the dissociation of H 2 S into S species is a spontaneous process with respect to molecular adsorption H 2 S. However, on sulfur-containing Surface, the presence of Surface S atom goes against the H S bond-breaking process both thermodynamically and kinetically. Finally, the vibrational frequencies for the adsorbed H 2 S, SH and S species on these Surfaces have been obtained, which can be applied to Guide Surface vibrational spectroscopy in experiment.

Hongyan Liu - One of the best experts on this subject based on the ideXlab platform.

  • a mechanistic study of h2s adsorption and dissociation on cu2o 1 1 1 Surfaces thermochemistry reaction barrier
    Applied Surface Science, 2012
    Co-Authors: Riguang Zhang, Hongyan Liu, Lixia Ling, Baojun Wang
    Abstract:

    Abstract The interaction mechanism of H 2 S with different Cu 2 O(1 1 1) Surfaces, including perfect, oxygen-vacancy and sulfur-containing Surfaces, have been systematically studied using periodic density functional calculations. Different kinds of possible modes of H 2 S, as well as the resultant SH and S species adsorbed on these Surfaces are identified. Two types of pathways via molecular and dissociative adsorption processes are mapped out. Our results show that sulfur species (H 2 S, SH and S) interact with Surface Cu centers; H 2 S exists in the form of molecular adsorption on perfect and sulfur-containing Surfaces; the dissociative adsorption of H 2 S occurs predominantly on oxygen-vacancy Surface, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward the dissociation of H 2 S. On the other hand, the dissociation processes of the molecular and dissociative adsorption H 2 S, leading to final product S species on these Cu 2 O(1 1 1) Surfaces, show that the overall dissociation process is exothermic. Meanwhile, with respect to molecular adsorption H 2 S, the activation barrier and reaction energy of the overall dissociation process on perfect and oxygen-vacancy Surfaces indicate that H 2 S can easily dissociate into S species. Importantly, in the case of dissociative adsorption of H 2 S, the dissociation of H 2 S into S species is a spontaneous process with respect to molecular adsorption H 2 S. However, on sulfur-containing Surface, the presence of Surface S atom goes against the H S bond-breaking process both thermodynamically and kinetically. Finally, the vibrational frequencies for the adsorbed H 2 S, SH and S species on these Surfaces have been obtained, which can be applied to Guide Surface vibrational spectroscopy in experiment.

A Uneri - One of the best experts on this subject based on the ideXlab platform.

  • robotic drill Guide positioning using known component 3d 2d image registration
    Journal of medical imaging, 2018
    Co-Authors: Vignesh Ramchandran, Jeffrey H Siewerdsen, A Uneri
    Abstract:

    A method for x-ray image-Guided robotic instrument positioning is reported and evaluated in preclinical studies of spinal pedicle screw placement with the aim of improving delivery of transpedicle K-wires and screws. The known-component (KC) registration algorithm was used to register the three-dimensional patient CT and drill Guide Surface model to intraoperative two-dimensional radiographs. Resulting transformations, combined with offline hand-eye calibration, drive the robotically held drill Guide to target trajectories defined in the preoperative CT. The method was assessed in comparison with a more conventional tracker-based approach, and robustness to clinically realistic errors was tested in phantom and cadaver. Deviations from planned trajectories were analyzed in terms of target registration error (TRE) at the tooltip (mm) and approach angle (deg). In phantom studies, the KC approach resulted in [Formula: see text] and [Formula: see text], comparable with accuracy in tracker-based approach. In cadaver studies with realistic anatomical deformation, the KC approach yielded [Formula: see text] and [Formula: see text], with statistically significant improvement versus tracker ([Formula: see text] and [Formula: see text]). Robustness to deformation is attributed to relatively local rigidity of anatomy in radiographic views. X-ray guidance offered accurate robotic positioning and could fit naturally within clinical workflow of fluoroscopically Guided procedures.

  • robotic drill Guide positioning using known component 3d 2d image registration
    Journal of medical imaging, 2018
    Co-Authors: Thomas Yi, Vignesh Ramchandran, Jeffrey H Siewerdsen, A Uneri
    Abstract:

    A method for x-ray image-Guided robotic instrument positioning is reported and evaluated in preclinical studies of spinal pedicle screw placement with the aim of improving delivery of transpedicle K-wires and screws. The known-component (KC) registration algorithm was used to register the three-dimensional patient CT and drill Guide Surface model to intraoperative two-dimensional radiographs. Resulting transformations, combined with offline hand–eye calibration, drive the robotically held drill Guide to target trajectories defined in the preoperative CT. The method was assessed in comparison with a more conventional tracker-based approach, and robustness to clinically realistic errors was tested in phantom and cadaver. Deviations from planned trajectories were analyzed in terms of target registration error (TRE) at the tooltip (mm) and approach angle (deg). In phantom studies, the KC approach resulted in TRE=1.51±0.51  mm and 1.01  deg±0.92  deg, comparable with accuracy in tracker-based approach. In cadaver studies with realistic anatomical deformation, the KC approach yielded TRE=2.31±1.05  mm and 0.66  deg±0.62  deg, with statistically significant improvement versus tracker (TRE=6.09±1.22  mm and 1.06  deg±0.90  deg). Robustness to deformation is attributed to relatively local rigidity of anatomy in radiographic views. X-ray guidance offered accurate robotic positioning and could fit naturally within clinical workflow of fluoroscopically Guided procedures.