Sensitization of Perovskite Strontium Stannate SrSnO 3 towards Visible-Light Absorption by Doping

Perovskite strontium stannate SrSnO 3 is a promising photocatalyst. However, its band gap is too large for efficient solar energy conversion. In order to sensitize SrSnO 3 toward visible-light activities, the effects of doping with various selected cations and anions are investigated by using hybrid density functional calculations. Results show that doping can result in dopant level to conduction band transitions which lie lower in energy compared to the original band gap transition. Therefore, it is expected that doping SrSnO 3 can induce visible-light absorption

Theoretical model for artificial structure modulation of HfO2/SiOx/Si interface by deposition of a dopant material

Realization of an abrupt HfO2/Si interface without unintentional oxidation of the silicon substrate is a crucial task for the development of modern field-effect transistors. Here, we present a theoretical model which suggests that deposition of a dopant material on the HfO2 layer turns it into an oxygen absorber, suppressing the formation of SiOx at the interface. Tantalum is predicted as an effective dopant in HfO2 for this purpose

2D Slice-driven Physics-based 3D Motion Estimation Framework for Pancreatic Radiotherapy

Pancreatic diseases are difficult to treat with high doses of radiation, as they often present both periodic and aperiodic deformations. Nevertheless, we expect that these difficulties can be overcome, and treatment results may be improved with the practical use of a device that can capture 2D slices of organs during irradiation. However, since only a few 2D slices can be taken, the 3D motion needs to be estimated from partially observed information. In this study, we propose a physics-based framework for estimating the 3D motion of organs, regardless of periodicity, from motion information obtained by 2D slices in one or more directions and a regression model that estimates the accuracy of the proposed framework to select the optimal slice. Using information obtained by slice-to-slice registration and setting the surrounding organs as boundaries, the framework drives the physical models for estimating 3D motion. The R2 score of the proposed regression model was greater than 0.9, and the RMSE was 0.357 mm. The mean errors were 5.11 $\pm$ 1.09 mm using an axial slice and 2.13 $\pm$ 0.598 mm using concurrent axial, sagittal, and coronal slices. Our results suggest that the proposed framework is comparable to volume-to-volume registration, and is feasible

Reduction in charged defects associated with oxygen vacancies in hafnia by magnesium incorporation: First-principles study

Charged defects in a gate insulating oxide significantly degrade electric properties of the field-effect transistors. We report on our analysis of the effects of Mg incorporation into HfO2 upon reduction in the positive charges associated with oxygen vacancies VO+2. Our comprehensive study using first-principles calculations revealed that a Mg atom substituted for Hf is stable in charge negative MgHf-2 and strongly binds with VO+2, neutralizing the defect. This contributes to the suppressing of the electron traps at the defect site, improving the reliability of Hf-based gate oxides

Sensitization of Perovskite Strontium Stannate SrSnO 3

Perovskite strontium stannate SrSnO3 is a promising photocatalyst. However, its band gap is too large for efficient solar energy conversion. In order to sensitize SrSnO3 toward visible-light activities, the effects of doping with various selected cations and anions are investigated by using hybrid density functional calculations. Results show that doping can result in dopant level to conduction band transitions which lie lower in energy compared to the original band gap transition. Therefore, it is expected that doping SrSnO3 can induce visible-light absorption

Sulfur and Silicon Doping in Ag₃PO₄

Silver orthophosphate (Ag₃PO₄) is known as a highly active visible-light sensitized photocatalyst, yet its doping effects on electric properties have not been well understood. Using hybrid density-functional calculations, we study possibilities for <i>n</i>-type and <i>p</i>-type doping in Ag₃PO₄. It is found that a sulfur substituted for phosphorus (S_P) has a relatively low formation energy (high solubility) and acts as a shallow donor in any growth conditions examined. Whereas, a substitutional silicon at phosphorus site (Si_P) is a deep acceptor and its solubility is low, indicating that <i>p</i>-type conductivity is unlikely to occur by Si doping. Our results suggest that sulfur doping is a promising approach for the realization of <i>n</i>-type Ag₃PO₄

Vers l'etude des interactions eau-proteine-sels dans les tissus biologiques : analyse enthalpique differentielle des solutions mimetiques des liquides biologiques

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc