The Experts below are selected from a list of 556233 Experts worldwide ranked by ideXlab platform
Darren Roblyer - One of the best experts on this subject based on the ideXlab platform.
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deep learning model for ultrafast multifrequency Optical Property extractions for spatial frequency domain imaging
Optics Letters, 2018Co-Authors: Yanyu Zhao, Yue Deng, Hannah Peterson, Raeef Istfan, Darren RoblyerAbstract:Spatial frequency domain imaging (SFDI) is emerging as an important new method in biomedical imaging due to its ability to provide label-free, wide-field tissue Optical Property maps. Most prior SFDI studies have utilized two spatial frequencies (2−fx) for Optical Property extractions. The use of more than two frequencies (multi−fx) can vastly improve the accuracy and reduce uncertainties in Optical Property estimates for some tissue types, but it has been limited in practice due to the slow speed of available inversion algorithms. We present a deep learning solution that eliminates this bottleneck by solving the multi−fx inverse problem 300× to 100,000× faster, with equivalent or improved accuracy compared to competing methods. The proposed deep learning inverse model will help to enable real-time and highly accurate tissue measurements with SFDI.
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frequency selection with Optical Property uncertainty estimates for spatial frequency domain imaging
Biophotonics Congress: Biomedical Optics Congress 2018 (Microscopy Translational Brain OTS) (2018) paper JTu3A.31, 2018Co-Authors: Vivian Pera, Kavon Karrobi, Syeda Tabassum, Fei Teng, Darren RoblyerAbstract:We present a method to generate Optical Property uncertainty estimates from knowledge of diffuse reflectance measurement errors for spatial frequency domain imaging. Our method can help optimize spatial frequency selection for a given application.
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Optical Property uncertainty estimates for spatial frequency domain imaging
Biomedical Optics Express, 2018Co-Authors: Vivian Pera, Kavon Karrobi, Syeda Tabassum, Fei Teng, Darren RoblyerAbstract:Spatial frequency domain imaging (SFDI) is a wide-field diffuse Optical imaging modality that has attracted considerable interest in recent years. Typically, diffuse reflectance measurements of spatially modulated light are used to quantify the Optical absorption and reduced scattering coefficients of tissue, and with these, chromophore concentrations are extracted. However, uncertainties in estimated absorption and reduced scattering coefficients are rarely reported, and we know of no method capable of providing these when look-up table (LUT) algorithms are used to recover the Optical properties. We present a method to generate Optical Property uncertainty estimates from knowledge of diffuse reflectance measurement errors. By employing the Cramer-Rao bound, we can quickly and efficiently explore theoretical SFDI performance as a function of spatial frequencies and sample Optical properties, allowing us to optimize spatial frequency selection for a given application. In practice, we can also obtain useful uncertainty estimates for Optical properties recovered with a two-frequency LUT algorithm, as we demonstrate with tissue-simulating phantom and in vivo experiments. Finally, we illustrate how absorption coefficient uncertainties can be propagated forward to yield uncertainties for chromophore concentrations, which could significantly impact the interpretation of experimental results.
Shangpeng Gao - One of the best experts on this subject based on the ideXlab platform.
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the stability electronic structure and Optical Property of tio2 polymorphs
Journal of Physical Chemistry C, 2014Co-Authors: Tong Zhu, Shangpeng GaoAbstract:Enthalpies of nine TiO2 polymorphs under different pressures are presented to study the relative stability of the TiO2 polymorphs. It is important to include the dispersion correction for van der Waals interaction and the Hubbard U term for the Ti 3d orbital in the DFT-GGA calculation to correctly reproduce the relative stability of rutile, brookite, and anatase. Band structures for the TiO2 polymorphs are calculated by density functional theory with generalized gradient approximation, and the band energies at high symmetry k-points are corrected using the GW method to accurately determine the band gap. The differences between direct band gap energies and indirect band gap energies are very small for rutile and columbite-structured TiO2, indicating a quasi-direct band gap character. For Optical response calculations, two-particle effects have been included by solving the Bethe–Salpeter equation for Coulomb correlated electron–hole pairs. TiO2 with baddeleyite, pyrite, and fluorite structures has Optical t...
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the stability electronic structure and Optical Property of tio2 polymorphs
arXiv: Materials Science, 2013Co-Authors: Tong Zhu, Shangpeng GaoAbstract:Phonon density of states calculation shows that a new TiO2 polymorph with tridymite structure is mechanically stable. Enthalpies of 9 TiO2 polymorphs under different pressure are presented to study the relative stability of the TiO2 polymorphs. Band structures for the TiO2 polymorphs are calculated by density functional theory with generalized gradient approximation and the band energies at high symmetry k-points are corrected using the GW method to accurately determine the band gap. The differences between direct band gap energies and indirect band gap energies are very small for rutile, columbite and baddeleyite TiO2, indicating a quasi-direct band gap character. The band gap energies of baddeleyite (quasi-direct) and brookite (direct) TiO2 are close to that of anatase (indirect) TiO2. The band gap of the newly predicted tridymite-structured TiO2 is wider than the other 8 polymorphs. For Optical response calculations, two-particle effects have been included by solving the Bethe-Salpeter equation for Coulomb correlated electron-hole pairs. TiO2 with cotunnite, pyrite, and fluorite structures have Optical transitions in the visible light region.
Xing Li - One of the best experts on this subject based on the ideXlab platform.
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synthesis crystal structure and nonlinear Optical Property of csv2o5
ChemInform, 2013Co-Authors: Yuebao Li, Xing LiAbstract:Single crystals of CsV2O5 are prepared by solid state reaction of stoichiometric amounts of Cs2CO3 and V2O5 (Pt crucible, 500 °C, 120 h).
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synthesis crystal structure and nonlinear Optical Property of csv2o5
Inorganic Chemistry Communications, 2013Co-Authors: Yuebao Li, Xing LiAbstract:Abstract The new nonlinear Optical crystal CsV2O5 has been synthesized by solid state reaction and characterized by single-crystal X-ray diffraction and thermogravimetric analysis. The crystal CsV2O5 crystallizes in the orthorhombic system with space Ima2 space group. It is a layered structure that is very flat and strongly parallel to c. The striking structural feature is that the V atom in single crystallographic site has two different valence states (V4+ and V5+). The [V2O5]n layer consists of corner-linked tetrahedron. The six tetrahedrons lie very nearly in the same z-plane forming almost regular hexagons. The Kurtz powder SHG measurement, using 1064 nm radiation, showed that the second-harmonic generation efficiency of CsV2O5 is about six times that of KDP.
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synthesis crystal structure and nonlinear Optical Property of rb3v5o14
ChemInform, 2011Co-Authors: Yuebao Li, Lingyan Zhao, Xing LiAbstract:The title compound is synthesized by solid state reaction of Rb2CO3 with 3% excess V2O5 (500 °C, Pt crucible, 24 h).
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synthesis crystal structure and nonlinear Optical Property of rb3v5o14
Journal of Solid State Chemistry, 2010Co-Authors: Yuebao Li, Lingyan Zhao, Xing LiAbstract:Abstract The new nonlinear Optical crystal Rb 3 V 5 O 14 has been synthesized by solid state reaction and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The crystal Rb 3 V 5 O 14 crystallizes in the trigonal system with space P 31 m (No. 157), a = b =8.7134(12) A, c =5.2807(11) A and α =90°, β =90°, γ =120°, Z= 1, ρ =3.516 g/cm 3 . It is a layered structure that is very flat and strongly parallel to c . The V 5 O 14 layer structure consists of corner-linked square and triangular pyramids. The layers are separated by Rb + ions, which fit equally well on the V 5 O 14 layer. The Kurtz powder SHG measurement, using 1064 nm radiation, showed that the second-harmonic generation efficiency of Rb 3 V 5 O 14 is about two times that of KDP.
Jiyong Yao - One of the best experts on this subject based on the ideXlab platform.
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synthesis structure Optical Property and electronic structure of ba7agga5se15
Journal of Alloys and Compounds, 2013Co-Authors: Wenlong Yin, Kai Feng, Wenyu Hao, Jiyong YaoAbstract:Abstract A new quaternary chalcogenide Ba 7 AgGa 5 Se 15 was synthesized by solid state reaction. It crystallizes in a new structure type in the noncentrosymmetric space group P 31 c of the trigonal system. In the structure, three Ga2Se 4 tetrahedra and one Ga1Se 4 tetrahedron are connected to each other by corner-sharing to form [Ga 4 Se 10 ] 8− anion clusters, which are further connected to AgSe 4 tetrahedra by corner-sharing to form a three-dimensional framework with Ba, Se7, and isolated Ga3Se 4 tetrahedra residing in the cavities. The Optical band gap of 2.60 (2) eV for Ba 7 AgGa 5 Se 15 was deduced from the diffuse reflectance spectrum. From a band structure calculation, Ba 7 AgGa 5 Se 15 is a direct semiconductor and the transition between Se and Ba plays an important role in the band gap.
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synthesis structure Optical Property and electronic structure of ba7agga5se15
ChemInform, 2013Co-Authors: Wenlong Yin, Kai Feng, Wenyu Hao, Jiyong YaoAbstract:Reddish orange single crystals of the new title compound are prepared by solid state reaction of BaSe and AgGaSe2 in the molar ratio 2:1 (sealed silica tube, 1273 K, 48 h).
Yan Wang - One of the best experts on this subject based on the ideXlab platform.
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one pot synthesis and Optical Property of copper i sulfide nanodisks
Inorganic Chemistry, 2010Co-Authors: Yan Wang, Yongxing Hu, Qiao Zhang, Jianping Ge, Zhenda LuAbstract:Copper(I) sulfide (Cu2S) nanodisks with controllable size and aspect ratio have been synthesized by using a one-pot colloidal process, in which no pre-prepared organometallic precursors are required. The reaction involves the injection of dodecanethiol into a hot solution containing copper salt, surfactants, and a high boiling-point organic solvent. Copper thiolate forms at the beginning of the reaction which effectively acts as a precursor whose decomposition leads to further nucleation and growth of Cu2S nanocrystals. The nanocrystals begin as small nanodots in the early stages of the reaction, gradually turning into nanodisks with aspect ratios (average disk diameter divided by thickness) up to 2.0, while the band gap of the nanocrystals decreases accordingly. As the growth of nanocrystals follows the monomer addition mechanism, the diameter, thickness, aspect ratio, and Optical Property of the Cu2S nanodisks can be tuned systematically by changing the reaction time, the amount of surfactants, and the ...
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one pot synthesis and Optical Property of copper i sulfide nanodisks
Inorganic Chemistry, 2010Co-Authors: Yan Wang, Qiao Zhang, Yanbing Hou, Yadong YinAbstract:Copper(I) sulfide (Cu(2)S) nanodisks with controllable size and aspect ratio have been synthesized by using a one-pot colloidal process, in which no pre-prepared organometallic precursors are required. The reaction involves the injection of dodecanethiol into a hot solution containing copper salt, surfactants, and a high boiling-point organic solvent. Copper thiolate forms at the beginning of the reaction which effectively acts as a precursor whose decomposition leads to further nucleation and growth of Cu(2)S nanocrystals. The nanocrystals begin as small nanodots in the early stages of the reaction, gradually turning into nanodisks with aspect ratios (average disk diameter divided by thickness) up to 2.0, while the band gap of the nanocrystals decreases accordingly. As the growth of nanocrystals follows the monomer addition mechanism, the diameter, thickness, aspect ratio, and Optical Property of the Cu(2)S nanodisks can be tuned systematically by changing the reaction time, the amount of surfactants, and the concentration of the precursors. This synthesis provides a simple and highly reproducible method for the preparation of Cu(2)S nanocrystals that may find potential applications in the fabrication of photovoltaic devices.