scholarly journals Scanning-Fit Analysis of fs-Spectroscopic Data

2000 ◽  
Vol 18 (4) ◽  
pp. 203-217 ◽  
Author(s):  
Mark Bischoff ◽  
Gregor Stobrawa ◽  
Sabine Rentsch
Keyword(s):  
Data Analysis ◽  
Spectroscopic Data ◽  
Simulated Data ◽  
Relaxation Processes ◽  
Molecular Relaxation ◽  
Nuclear Dynamics ◽  
Pump Probe ◽  
Time Constants ◽  
Global Data

The scanning-fit method was developed for the global data analysis of pump-probe data. This method is useful in cases when pulse durations are adjusted to be short compared with nuclear dynamics and long compared with the dephasing timescales. Then multiexponential functions can be used to describe the mono molecular relaxation processes and the scanning-fit method increases the accuracy of the calculated time constants, yields detailed information about their ranges of confidence and their dependency from each other. In this paper we describe the method in detail and demonstrate its application to simulated data. Additionally, we report about the results which were obtained from scanning-fit analysis in case of the photoisomerization of pinacyanol and the light induced processes in phycocyanobilin.

scholarly journals Bayesian modeling and significant features exploration in wavelet power spectra

2007 ◽  
Vol 14 (1) ◽  
pp. 79-88 ◽  
Author(s):  
D. V. Divine ◽  
F. Godtliebsen
Keyword(s):  
Data Analysis ◽  
Traditional Approach ◽  
Statistical Significance ◽  
Power Spectra ◽  
Simulated Data ◽  
Scale Space ◽  
Independent Random Variables ◽  
Discrete Wavelet ◽  
Wavelet Coefficients ◽  
Testing Procedures

Abstract. This study proposes and justifies a Bayesian approach to modeling wavelet coefficients and finding statistically significant features in wavelet power spectra. The approach utilizes ideas elaborated in scale-space smoothing methods and wavelet data analysis. We treat each scale of the discrete wavelet decomposition as a sequence of independent random variables and then apply Bayes' rule for constructing the posterior distribution of the smoothed wavelet coefficients. Samples drawn from the posterior are subsequently used for finding the estimate of the true wavelet spectrum at each scale. The method offers two different significance testing procedures for wavelet spectra. A traditional approach assesses the statistical significance against a red noise background. The second procedure tests for homoscedasticity of the wavelet power assessing whether the spectrum derivative significantly differs from zero at each particular point of the spectrum. Case studies with simulated data and climatic time-series prove the method to be a potentially useful tool in data analysis.

scholarly journals A pump–probe scheme with a single chirped pulse to image electron and nuclear dynamics in molecules

2018 ◽  
Vol 20 (12) ◽  
pp. 123004 ◽  
Author(s):  
Denis Jelovina ◽  
Johannes Feist ◽  
Fernando Martín ◽  
Alicia Palacios
Keyword(s):  
Nuclear Dynamics ◽  
Pump Probe ◽  
Chirped Pulse

scholarly journals Extraction and Determinationof Chemical Structure from flower Dicholomethane Extract of Catharanthus roseus

2021 ◽  
Vol 68 (2) ◽  
Author(s):  
Shahin Aziza ◽  
Koushik Sahab ◽  
Md. Abdus Satter Miac ◽  
Md. Hemayet Hossaina
Keyword(s):  
Data Analysis ◽  
Oleanolic Acid ◽  
Catharanthus Roseus ◽  
Spectroscopic Data ◽  
Chemical Structure

Catharanthus roseus is considered a cooling medicine. Two compounds: ?-sitosterol (1) and 3?-Hydroxy-lup-20 (29)-en-28-oic acid or Oleanolic acid (2) have been isolated from flowers from Dicholoromethane extract of Catharanthus roseus. By different spectroscopic data analysis the structures of the compounds have been established.

scholarly journals Measurement of the delayed-neutron multiplicity and time constants in the thermal neutron induced fission of 235U at ILL

2020 ◽  
Vol 239 ◽  
pp. 18006
Author(s):  
Daniela Foligno ◽  
Pierre Leconte ◽  
Olivier Serot ◽  
Benoit Geslot ◽  
Grégoire De Izarra ◽  
...  
Keyword(s):  
Data Analysis ◽  
Cold Neutron ◽  
Average Lifetime ◽  
Reactor Safety ◽  
Delayed Neutron ◽  
Delayed Neutrons ◽  
Time Constants ◽  
Experimental Campaign ◽  
Safety Margins ◽  
Induced Fission

Delayed-neutron (DN) data is essential in inherent reactor safety and reactor control since it is needed for the estimation of the reactivity. Nowadays, discrepancies among the data in various international databases (JEFF, ENDF, JENDL) are large and bring excessive conservatism in the safety margins. The ALDEN (Average Lifetime of DElayed Neutrons) experiment, built in a collaboration between CEA and CNRS, aimed at re-measuring the DN data associated with several fissioning systems (average delayed-neutron yield and kinetic parameters). The first experimental campaign consisted in the integral measurement of the DN activity after the irradiation of an 235U target. It took place under the cold neutron flux of ILL (Institut Laue-Langevin) at the beginning of September 2018, in the PF1b experimental zone (doi:10.1016/j.nima.2006.03.020). The data analysis gave an average DN yield of 1.631E-02(2) DN/fiss and a mean precursors’ half-life of 8.93(9) s. The results are consistent with the literature, but they are affected by one third of the uncertainty.

Infrastructures and Ionograms

2017 ◽  
Keyword(s):  
Data Analysis ◽  
Mass Production ◽  
Automated System ◽  
Natural Order ◽  
The Core ◽  
Ground Station ◽  
Data Flows ◽  
The World ◽  
Formed Part ◽  
Global Data

This chapter explores how the Alouette satellite’s reorientation of global data flows and mass-production of ionograms altered the natural order at the core of DRTE’s research. The satellite’s unexpected reliability demanded an automated system of data analysis. Automation, when applied to the ionogram, effaced the complexity used to characterize the ionosphere above Canada and explain violent communications disruptions. The chapter first analyzes the debates over the organization of the satellite’s global ground station network, the control of the satellite, the collaboration with NASA, and the sharing of data. It then examines how these considerations formed part of the technical design of the satellite, and specifically how they required a system for mass-producing ionograms from global data gathered around the world. The chapter’s final section focuses on the resulting problems of data analysis that this system produced and the new reading techniques devised to analyze the overwhelming number of records.

scholarly journals Discrete Spherical Harmonic Transforms of Nearly Equidistributed Global Data

2011 ◽  
Vol 1 (3) ◽  
pp. 251-258 ◽  
Author(s):  
J. Blais
Keyword(s):  
Spherical Harmonic ◽  
Fourier Transforms ◽  
Simulated Data ◽  
Geopotential Model ◽  
Structural Constraints ◽  
Geopotential Models ◽  
Analysis And Synthesis ◽  
Comparative Results ◽  
Efficiency And Reliability ◽  
Global Data

Discrete Spherical Harmonic Transforms of Nearly Equidistributed Global DataDiscrete Spherical Harmonic Transforms (SHTs) are commonly defined for equiangular grids on the sphere. However, when global array data exhibit near equidistributed patterns rather than equiangular grids, discrete SHTs require appropriate adaptations for analysis and synthesis. Computational efficiency and reliability impose structural constraints on possible equidistribution characteristics of data patterns such as for instance with Chebychev quadratures and Fast Fourier Transforms (FFTs). Following some general introduction to discrete SHTs and equidistributions on the sphere, equitriangular (near equiareal) lattices based on the octahedron and the icosahedron are introduced for SHT analysis and synthesis. The developed formulations are described and implemented using simulated data and geopotential models such as the Earth Geopotential Model EGM 2008. Comparative results for analysis and synthesis at different levels of resolution show the potential of the spherical equitriangular approach for geodetic and other applications with nearly equidistributed global data.

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