scholarly journals Photon spectrum and angle distribution for photon scattering with relativistic Maxwellian electrons

2019 ◽  
Vol 68 (1) ◽  
pp. 015201
Author(s):  
Li Shu
Keyword(s):  
Photon Spectrum ◽  
Angle Distribution ◽  
Photon Scattering

Sequence Specific Dihedral Angle Distribution: Application in Protein Structure Prediction and Evaluation

1970 ◽  
Vol 19 (2) ◽  
pp. 217-226
Author(s):  
S. M. Minhaz Ud-Dean ◽  
Mahdi Muhammad Moosa
Keyword(s):  
Protein Structure ◽  
Dihedral Angle ◽  
Protein Structure Prediction ◽  
Structure Prediction ◽  
Protein Structures ◽  
Angle Distribution ◽  
Ramachandran Plot ◽  
Specific Data ◽  
Specific Distribution ◽  
Structure Evaluation

Protein structure prediction and evaluation is one of the major fields of computational biology. Estimation of dihedral angle can provide information about the acceptability of both theoretically predicted and experimentally determined structures. Here we report on the sequence specific dihedral angle distribution of high resolution protein structures available in PDB and have developed Sasichandran, a tool for sequence specific dihedral angle prediction and structure evaluation. This tool will allow evaluation of a protein structure in pdb format from the sequence specific distribution of Ramachandran angles. Additionally, it will allow retrieval of the most probable Ramachandran angles for a given sequence along with the sequence specific data. Key words: Torsion angle, φ-ψ distribution, sequence specific ramachandran plot, Ramasekharan, protein structure appraisal D.O.I. 10.3329/ptcb.v19i2.5439 Plant Tissue Cult. & Biotech. 19(2): 217-226, 2009 (December)

Imaging through Scattering Media with a Learning Based Prior

2020 ◽  
Vol 2020 (14) ◽  
pp. 306-1-306-6
Author(s):  
Florian Schiffers ◽  
Lionel Fiske ◽  
Pablo Ruiz ◽  
Aggelos K. Katsaggelos ◽  
Oliver Cossairt
Keyword(s):  
Optimization Problem ◽  
Autonomous Driving ◽  
Scattering Media ◽  
Photon Scattering ◽  
Point Spread ◽  
Spread Function ◽  
Radiative Transport Equation ◽  
Spatio Temporal ◽  
Transient Imaging

Imaging through scattering media finds applications in diverse fields from biomedicine to autonomous driving. However, interpreting the resulting images is difficult due to blur caused by the scattering of photons within the medium. Transient information, captured with fast temporal sensors, can be used to significantly improve the quality of images acquired in scattering conditions. Photon scattering, within a highly scattering media, is well modeled by the diffusion approximation of the Radiative Transport Equation (RTE). Its solution is easily derived which can be interpreted as a Spatio-Temporal Point Spread Function (STPSF). In this paper, we first discuss the properties of the ST-PSF and subsequently use this knowledge to simulate transient imaging through highly scattering media. We then propose a framework to invert the forward model, which assumes Poisson noise, to recover a noise-free, unblurred image by solving an optimization problem.

Effects of Multiple Photon Scattering in Deciduous Tree Canopies

2009 ◽  
Author(s):  
Michael Greiner ◽  
Bradley D. Duncan ◽  
Matthew P. Dierking
Keyword(s):  
Deciduous Tree ◽  
Photon Scattering ◽  
Tree Canopies

Measurement of small-angle photon scattering for some breast tissues and tissue substitute materials

1991 ◽  
Vol 36 (1) ◽  
pp. 7-18 ◽  
Author(s):  
S H Evans ◽  
D A Bradley ◽  
D R Dance ◽  
J E Bateman ◽  
C H Jones
Keyword(s):  
Small Angle ◽  
Photon Scattering ◽  
Breast Tissues ◽  
Substitute Materials

scholarly journals Control of quantum electrodynamical processes by shaping electron wavepackets

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liang Jie Wong ◽  
Nicholas Rivera ◽  
Chitraang Murdia ◽  
Thomas Christensen ◽  
John D. Joannopoulos ◽  
...  
Keyword(s):  
Free Electron ◽  
Spectral Characteristics ◽  
Modern Science ◽  
Optical Excitation ◽  
Field Theories ◽  
Photon Scattering ◽  
Precise Control ◽  
Bremsstrahlung Emission ◽  
Superposition States ◽  
Electron Photon

AbstractFundamental quantum electrodynamical (QED) processes, such as spontaneous emission and electron-photon scattering, encompass phenomena that underlie much of modern science and technology. Conventionally, calculations in QED and other field theories treat incoming particles as single-momentum states, omitting the possibility that coherent superposition states, i.e., shaped wavepackets, can alter fundamental scattering processes. Here, we show that free electron waveshaping can be used to design interferences between two or more pathways in a QED process, enabling precise control over the rate of that process. As an example, we show that free electron waveshaping modifies both spatial and spectral characteristics of bremsstrahlung emission, leading for instance to enhancements in directionality and monochromaticity. The ability to tailor general QED processes opens up additional avenues of control in phenomena ranging from optical excitation (e.g., plasmon and phonon emission) in electron microscopy to free electron lasing in the quantum regime.

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