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Sample records for highly nonequilibrium fourier

  1. Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry.

    Science.gov (United States)

    van den Bekerom, Dirk; den Harder, Niek; Minea, Teofil; Gatti, Nicola; Linares, Jose Palomares; Bongers, Waldo; van de Sanden, Richard; van Rooij, Gerard

    2017-08-01

    A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

  2. Nonequilibrium Phase Chemistry in High Temperature Structure Alloys

    Science.gov (United States)

    Wang, R.

    1991-01-01

    Titanium and nickel aluminides of nonequilibrium microstructures and in thin gauge thickness were identified, characterized and produced for potential high temperature applications. A high rate sputter deposition technique for rapid surveillance of the microstructures and nonequilibrium phase is demonstrated. Alloys with specific compositions were synthesized with extended solid solutions, stable dispersoids, and specific phase boundaries associated with different heat treatments. Phase stability and mechanical behavior of these nonequilibrium alloys were investigated and compared.

  3. Entanglement in stationary nonequilibrium states at high energies

    OpenAIRE

    Znidaric, Marko

    2011-01-01

    In recent years it has been found that quantum systems can posses entanglement in equilibrium thermal states provided temperature is low enough. In the present work we explore a possibility of having entanglement in nonequilibrium stationary states. We show analytically that, in a simple one-dimensional spin chain, there is entanglement even at highest attainable energies; that is, starting from an equilibrium state at infinite temperature, a sufficiently strong driving can induce entanglemen...

  4. Entanglement in stationary nonequilibrium states at high energies

    Science.gov (United States)

    Žnidarič, Marko

    2012-01-01

    In recent years it has been found that quantum systems can posses entanglement in equilibrium thermal states provided temperature is low enough. In the present work we explore a possibility of having entanglement in nonequilibrium stationary states. We show analytically that, in a simple one-dimensional spin chain, there is entanglement even at the highest attainable energies; that is, starting from an equilibrium state at infinite temperature, a sufficiently strong driving can induce entanglement, even in the thermodynamic limit. We also show that dissipative dephasing, on the other hand, destroys entanglement.

  5. High Performance GPU-Based Fourier Volume Rendering

    Directory of Open Access Journals (Sweden)

    Marwan Abdellah

    2015-01-01

    Full Text Available Fourier volume rendering (FVR is a significant visualization technique that has been used widely in digital radiography. As a result of its O(N2log⁡N time complexity, it provides a faster alternative to spatial domain volume rendering algorithms that are O(N3 computationally complex. Relying on the Fourier projection-slice theorem, this technique operates on the spectral representation of a 3D volume instead of processing its spatial representation to generate attenuation-only projections that look like X-ray radiographs. Due to the rapid evolution of its underlying architecture, the graphics processing unit (GPU became an attractive competent platform that can deliver giant computational raw power compared to the central processing unit (CPU on a per-dollar-basis. The introduction of the compute unified device architecture (CUDA technology enables embarrassingly-parallel algorithms to run efficiently on CUDA-capable GPU architectures. In this work, a high performance GPU-accelerated implementation of the FVR pipeline on CUDA-enabled GPUs is presented. This proposed implementation can achieve a speed-up of 117x compared to a single-threaded hybrid implementation that uses the CPU and GPU together by taking advantage of executing the rendering pipeline entirely on recent GPU architectures.

  6. High Performance GPU-Based Fourier Volume Rendering.

    Science.gov (United States)

    Abdellah, Marwan; Eldeib, Ayman; Sharawi, Amr

    2015-01-01

    Fourier volume rendering (FVR) is a significant visualization technique that has been used widely in digital radiography. As a result of its (N (2)log⁡N) time complexity, it provides a faster alternative to spatial domain volume rendering algorithms that are (N (3)) computationally complex. Relying on the Fourier projection-slice theorem, this technique operates on the spectral representation of a 3D volume instead of processing its spatial representation to generate attenuation-only projections that look like X-ray radiographs. Due to the rapid evolution of its underlying architecture, the graphics processing unit (GPU) became an attractive competent platform that can deliver giant computational raw power compared to the central processing unit (CPU) on a per-dollar-basis. The introduction of the compute unified device architecture (CUDA) technology enables embarrassingly-parallel algorithms to run efficiently on CUDA-capable GPU architectures. In this work, a high performance GPU-accelerated implementation of the FVR pipeline on CUDA-enabled GPUs is presented. This proposed implementation can achieve a speed-up of 117x compared to a single-threaded hybrid implementation that uses the CPU and GPU together by taking advantage of executing the rendering pipeline entirely on recent GPU architectures.

  7. High-Throughput Screening Using Fourier-Transform Infrared Imaging

    Directory of Open Access Journals (Sweden)

    Erdem Sasmaz

    2015-06-01

    Full Text Available Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high-throughput (HT heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst studies, including various optical, mass-spectrometry, and gas-chromatography techniques. Of these, rapid-scanning Fourier-transform infrared (FTIR imaging is one of the fastest and most versatile screening techniques. Here, the new design of the 16-channel HT reactor is presented and test results for its accuracy and reproducibility are shown. The performance of the system was evaluated through the oxidation of CO over commercial Pd/Al2O3 and cobalt oxide nanoparticles synthesized with different reducer-reductant molar ratios, surfactant types, metal and surfactant concentrations, synthesis temperatures, and ramp rates.

  8. High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2015-01-01

    Full Text Available This paper addresses the discrimination of closely spaced high speed group targets with radar transmitting linear frequency modulation (LFM pulses. The high speed target motion leads to range migration and target dispersion and thereby the discriminating capability of the high range resolution profile (HRRP deteriorating significantly. An effective processing approach composed of stretch processing (SP, modified fractional Fourier transform (FrFT, and multiple signal classification (MUSIC algorithm is proposed to deal with this problem. Firstly, SP is adopted to transform the received LFM with Doppler distortions into narrow band LFM signals. Secondly, based on the two-dimensional range/velocity plane constructed by the modified FrFT, the velocity of the high speed group target is estimated and compensated with just one single pulse. After the compensation of range migration and target dispersion simultaneously, the resolution of the HRRP achieved by single pulse transmission improves significantly in the high speed group targets scenarios. Finally, MUSIC algorithm with superresolution capability is utilized to make a more explicit discrimination between the scatterers in comparison with the conventional SP method. Simulation results show the effectiveness of the proposed scheme.

  9. Rapid inactivation of Penicillium digitatum spores using high-density nonequilibrium atmospheric pressure plasma

    Science.gov (United States)

    Iseki, Sachiko; Ohta, Takayuki; Aomatsu, Akiyoshi; Ito, Masafumi; Kano, Hiroyuki; Higashijima, Yasuhiro; Hori, Masaru

    2010-04-01

    A promising, environmentally safe method for inactivating fungal spores of Penicillium digitatum, a difficult-to-inactivate food spoilage microorganism, was developed using a high-density nonequilibrium atmospheric pressure plasma (NEAPP). The NEAPP employing Ar gas had a high electron density on the order of 1015 cm-3. The spores were successfully and rapidly inactivated using the NEAPP, with a decimal reduction time in spores (D value) of 1.7 min. The contributions of ozone and UV radiation on the inactivation of the spores were evaluated and concluded to be not dominant, which was fundamentally different from the conventional sterilizations.

  10. Numerical Simulation of Non-Equilibrium Plasma Discharge for High Speed Flow Control

    Science.gov (United States)

    Balasubramanian, Ramakrishnan; Anandhanarayanan, Karupannasamy; Krishnamurthy, Rajah; Chakraborty, Debasis

    2017-06-01

    Numerical simulation of hypersonic flow control using plasma discharge technique is carried out using an in-house developed code CERANS-TCNEQ. The study is aimed at demonstrating a proof of concept futuristic aerodynamic flow control device. The Kashiwa Hypersonic and High Temperature wind tunnel study of plasma discharge over a flat plate had been considered for numerical investigation. The 7-species, 18-reaction thermo-chemical non-equilibrium, two-temperature air-chemistry model due Park is used to model the weakly ionized flow. Plasma discharge is modeled as Joule heating source terms in both the translation-rotational and vibrational energy equations. Comparison of results for plasma discharge at Mach 7 over a flat plate with the reference data reveals that the present study is able to mimic the exact physics of complex flow such as formation of oblique shock wave ahead of the plasma discharge region with a resultant rise in surface pressure and vibrational temperature up to 7000 K demonstrating the use of non-equilibrium plasma discharge for flow control at hypersonic speeds.

  11. Quantum entanglement at high temperatures? Bosonic systems in nonequilibrium steady state

    Energy Technology Data Exchange (ETDEWEB)

    Hsiang, Jen-Tsung [Center for Field Theory and Particle Physics, Department of Physics, Fudan University,Shanghai 200433 (China); Hu, B.L. [Center for Field Theory and Particle Physics, Department of Physics, Fudan University,Shanghai 200433 (China); Joint Quantum Institute and Maryland Center for Fundamental Physics, University of Maryland,College Park, Maryland 20742 (United States)

    2015-11-13

    This is the second of a series of three papers examining how viable it is for entanglement to be sustained at high temperatures for quantum systems in thermal equilibrium (Case A), in nonequilibrium (Case B) and in nonequilibrium steady state (NESS) conditions (Case C). The system we analyze here consists of two coupled quantum harmonic oscillators each interacting with its own bath described by a scalar field, set at temperatures T{sub 1}>T{sub 2}. For constant bilinear inter-oscillator coupling studied here (Case C1) owing to the Gaussian nature, the problem can be solved exactly at arbitrary temperatures even for strong coupling. We find that the valid entanglement criterion in general is not a function of the bath temperature difference, in contrast to thermal transport in the same NESS setting http://arxiv.org/abs/1405.7642. Thus lowering the temperature of one of the thermal baths does not necessarily help to safeguard the entanglement between the oscillators. Indeed, quantum entanglement will disappear if any one of the thermal baths has a temperature higher than the critical temperature T{sub c}, defined as the temperature above which quantum entanglement vanishes. With the Langevin equations derived we give a full display of how entanglement dynamics in this system depends on T{sub 1}, T{sub 2}, the inter-oscillator coupling and the system-bath coupling strengths. For weak oscillator-bath coupling the critical temperature T{sub c} is about the order of the inverse oscillator frequency, but for strong oscillator-bath coupling it will depend on the bath cutoff frequency. We conclude that in most realistic circumstances, for bosonic systems in NESS with constant bilinear coupling, ‘hot entanglement’ is largely a fiction.

  12. Development of a Novel Non-Equilibrium Pulsed Plasma Ignition Module for High Altitude Turbojets Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An experimental research program focusing on design, development, and testing of a novel nonequilibrium plasma ignition module is proposed. The ignition module will...

  13. Construction of Low Dissipative High Order Well-Balanced Filter Schemes for Non-Equilibrium Flows

    Science.gov (United States)

    Wang, Wei; Yee, H. C.; Sjogreen, Bjorn; Magin, Thierry; Shu, Chi-Wang

    2009-01-01

    The goal of this paper is to generalize the well-balanced approach for non-equilibrium flow studied by Wang et al. [26] to a class of low dissipative high order shock-capturing filter schemes and to explore more advantages of well-balanced schemes in reacting flows. The class of filter schemes developed by Yee et al. [30], Sjoegreen & Yee [24] and Yee & Sjoegreen [35] consist of two steps, a full time step of spatially high order non-dissipative base scheme and an adaptive nonlinear filter containing shock-capturing dissipation. A good property of the filter scheme is that the base scheme and the filter are stand alone modules in designing. Therefore, the idea of designing a well-balanced filter scheme is straightforward, i.e., choosing a well-balanced base scheme with a well-balanced filter (both with high order). A typical class of these schemes shown in this paper is the high order central difference schemes/predictor-corrector (PC) schemes with a high order well-balanced WENO filter. The new filter scheme with the well-balanced property will gather the features of both filter methods and well-balanced properties: it can preserve certain steady state solutions exactly; it is able to capture small perturbations, e.g., turbulence fluctuations; it adaptively controls numerical dissipation. Thus it shows high accuracy, efficiency and stability in shock/turbulence interactions. Numerical examples containing 1D and 2D smooth problems, 1D stationary contact discontinuity problem and 1D turbulence/shock interactions are included to verify the improved accuracy, in addition to the well-balanced behavior.

  14. Fourier Spot Volatility Estimator: Asymptotic Normality and Efficiency with Liquid and Illiquid High-Frequency Data

    Science.gov (United States)

    2015-01-01

    The recent availability of high frequency data has permitted more efficient ways of computing volatility. However, estimation of volatility from asset price observations is challenging because observed high frequency data are generally affected by noise-microstructure effects. We address this issue by using the Fourier estimator of instantaneous volatility introduced in Malliavin and Mancino 2002. We prove a central limit theorem for this estimator with optimal rate and asymptotic variance. An extensive simulation study shows the accuracy of the spot volatility estimates obtained using the Fourier estimator and its robustness even in the presence of different microstructure noise specifications. An empirical analysis on high frequency data (U.S. S&P500 and FIB 30 indices) illustrates how the Fourier spot volatility estimates can be successfully used to study intraday variations of volatility and to predict intraday Value at Risk. PMID:26421617

  15. High-resolution retinal imaging using adaptive optics and Fourier-domain optical coherence tomography

    Science.gov (United States)

    Olivier, Scot S.; Werner, John S.; Zawadzki, Robert J.; Laut, Sophie P.; Jones, Steven M.

    2010-09-07

    This invention permits retinal images to be acquired at high speed and with unprecedented resolution in three dimensions (4.times.4.times.6 .mu.m). The instrument achieves high lateral resolution by using adaptive optics to correct optical aberrations of the human eye in real time. High axial resolution and high speed are made possible by the use of Fourier-domain optical coherence tomography. Using this system, we have demonstrated the ability to image microscopic blood vessels and the cone photoreceptor mosaic.

  16. High-speed spectral domain optical coherence tomography using non-uniform fast Fourier transform

    Science.gov (United States)

    Chan, Kenny K. H.; Tang, Shuo

    2010-01-01

    The useful imaging range in spectral domain optical coherence tomography (SD-OCT) is often limited by the depth dependent sensitivity fall-off. Processing SD-OCT data with the non-uniform fast Fourier transform (NFFT) can improve the sensitivity fall-off at maximum depth by greater than 5dB concurrently with a 30 fold decrease in processing time compared to the fast Fourier transform with cubic spline interpolation method. NFFT can also improve local signal to noise ratio (SNR) and reduce image artifacts introduced in post-processing. Combined with parallel processing, NFFT is shown to have the ability to process up to 90k A-lines per second. High-speed SD-OCT imaging is demonstrated at camera-limited 100 frames per second on an ex-vivo squid eye. PMID:21258551

  17. A high capacity multiple watermarking scheme based on Fourier descriptor and Sudoku

    Science.gov (United States)

    Zhang, Li; Zheng, Huimin

    2015-12-01

    Digital watermark is a type of technology to hide some significant information which is mainly used to protect digital data. A high capacity multiple watermarking method is proposed, which adapts the Fourier descriptor to pre-process the watermarks, while a Sudoku puzzle is used as a reference matrix in embedding process and a key in extraction process. It can dramatically reduce the required capacity by applying Fourier descriptor. Meanwhile, the security of watermarks can be guaranteed due to the Sudoku puzzle. Unlike previous algorithms applying Sudoku puzzle in spatial domain, the proposed algorithm works in transformed domain by applying LWT2.In addition, the proposed algorithm can detect the temper location accurately. The experimental results demonstrated that the goals mentioned above have been achieved.

  18. The calculation of high-temperature equilibrium and nonequilibrium specific heat data for N2, O2 and NO

    Science.gov (United States)

    Jaffe, Richard L.

    1987-01-01

    Specific heat data for high-temperature air species are needed to compute the temperature and enthalpy of gas mixtures in aerothermodynamics flowfield calculations. Accurate data are known only for temperatures under 6000 K, but are required for temperatures exceeding 25,000 K. In the present study, CP data are computed for N2, O2 and NO. The calculations are based on summations over all the vibration-rotation energy levels for all known bound electronic states. Estimates are made for the error introduced by the neglect of possible additional high-lying electronic states. In addition, a scheme for the partitioning of the internal energy into vibrational, rotational and electronic contributions is presented which consistently accounts for the nonseparable nature of the various energy modes. The multitemperature specific heat data are recommended for use in nonequilibrium flowfield models.

  19. High-Temperature Nonequilibrium Bose Condensation Induced by a Hot Needle.

    Science.gov (United States)

    Schnell, Alexander; Vorberg, Daniel; Ketzmerick, Roland; Eckardt, André

    2017-10-06

    We investigate theoretically a one-dimensional ideal Bose gas that is driven into a steady state far from equilibrium via the coupling to two heat baths: a global bath of temperature T and a "hot needle," a bath of temperature T_{h}≫T with localized coupling to the system. Remarkably, this system features a crossover to finite-size Bose condensation at temperatures T that are orders of magnitude larger than the equilibrium condensation temperature. This counterintuitive effect is explained by a suppression of long-wavelength excitations resulting from the competition between both baths. Moreover, for sufficiently large needle temperatures ground-state condensation is superseded by condensation into an excited state, which is favored by its weaker coupling to the hot needle. Our results suggest a general strategy for the preparation of quantum degenerate nonequilibrium steady states with unconventional properties and at large temperatures.

  20. Numerical Investigation of Vertical Cavity Lasers With High-Contrast Gratings Using the Fourier Modal Method

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2016-01-01

    We explore the use of a modal expansion technique, Fourier modal method (FMM), for investigating the optical properties of vertical cavities employing high-contrast gratings (HCGs). Three techniques for determining the resonance frequency and quality factor (Q-factor) of a cavity mode are compared......, the scattering losses of several HCG-based vertical cavities with inplane heterostructures which have promising prospects for fundamental physics studies and on-chip laser applications, are investigated. This type of parametric study of 3D structures would be numerically very demanding using spatial...

  1. A new particle-like method for high-speed flows with chemical non-equilibrium

    Directory of Open Access Journals (Sweden)

    Fábio Rodrigues Guzzo

    2010-04-01

    Full Text Available The present work is concerned with the numerical simulation of hypersonic blunt body flows with chemical non-equilibrium. New theoretical and numerical formulations for coupling the chemical reaction to the fluid dynamics are presented and validated. The fluid dynamics is defined for a stationary unstructured mesh and the chemical reaction process is defined for “finite quantities” moving through the stationary mesh. The fluid dynamics is modeled by the Euler equations and the chemical reaction rates by the Arrhenius law. Ideal gases are considered. The thermodynamical data are based on JANNAF tables and Burcat’s database. The algorithm proposed by Liou, known as AUSM+, is implemented in a cell-centered based finite volume method and in an unstructured mesh context. Multidimensional limited MUSCL interpolation method is used to perform property reconstructions and to achieve second-order accuracy in space. The minmod limiter is used. The second order accuracy, five stage, Runge-Kutta time-stepping scheme is employed to perform the time march for the fluid dynamics. The numerical code VODE, which is part of the CHEMKIN-II package, is adopted to perform the time integration for the chemical reaction equations. The freestream reacting fluid is composed of H2 and air at the stoichiometric ratio. The emphasis of the present paper is on the description of the new methodology for handling the coupling of chemical and fluid mechanic processes, and its validation by comparison with the standard time-splitting procedure. The configurations considered are the hypersonic flow over a wedge, in which the oblique detonation wave is induced by an oblique shock wave, and the hypersonic flow over a blunt body. Differences between the solutions obtained with each formulation are presented and discussed, including the effects of grid refinement in each case. The primary objective of such comparisons is the validation of the proposed methodology. Moreover, for

  2. Negative velocity fluctuations and non-equilibrium fluctuation relation for a driven high critical current vortex state.

    Science.gov (United States)

    Bag, Biplab; Shaw, Gorky; Banerjee, S S; Majumdar, Sayantan; Sood, A K; Grover, A K

    2017-07-17

    Under the influence of a constant drive the moving vortex state in 2H-NbS2 superconductor exhibits a negative differential resistance (NDR) transition from a steady flow to an immobile state. This state possesses a high depinning current threshold ([Formula: see text]) with unconventional depinning characteristics. At currents well above [Formula: see text], the moving vortex state exhibits a multimodal velocity distribution which is characteristic of vortex flow instabilities in the NDR regime. However at lower currents which are just above [Formula: see text], the velocity distribution is non-Gaussian with a tail extending to significant negative velocity values. These unusual negative velocity events correspond to vortices drifting opposite to the driving force direction. We show that this distribution obeys the Gallavotti-Cohen Non-Equilibrium Fluctuation Relation (GC-NEFR). Just above [Formula: see text], we also find a high vortex density fluctuating driven state not obeying the conventional GC-NEFR. The GC-NEFR analysis provides a measure of an effective energy scale (E eff ) associated with the driven vortex state. The E eff corresponds to the average energy dissipated by the fluctuating vortex state above [Formula: see text]. We propose the high E eff value corresponds to the onset of high energy dynamic instabilities in this driven vortex state just above [Formula: see text].

  3. Nonequilibrium volumetric response of shocked polymers

    Energy Technology Data Exchange (ETDEWEB)

    Clements, B E [Los Alamos National Laboratory

    2009-01-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities remind us that the volumetric behavior also exhibits a non-equilibrium response. Experiments supporting the notion of a non-equilibrium volumetric behavior will be summarized. Following that discussion, a continuum-level theory is proposed that will account for both the equilibrium and non-equilibrium response. Upon finding agreement with experiment, the theory is used to study the relaxation of a shocked polymer back towards its shocked equilibrium state.

  4. Study on spectral calibration of an ultraviolet Fourier transform imaging spectrometer with high precision

    Science.gov (United States)

    Yang, Wenming; Liao, Ningfang; Cheng, Haobo; Li, Yasheng; Bai, Xueqiong; Deng, Chengyang

    2018-01-01

    In this paper, we reported the laboratory spectral calibration of an ultraviolet (UV) Fourier transform imaging spectrometer (FTIS). A short overview of the designed UV-FTIS, which feature with a Cassegrain objective, an Offner relay optics system and a spatial-and-temporal modulation Michelson structure, is given. The experimental setup of spectral calibration is described, including details of the light source and integrating sphere. A high pressure mercury lamp was used to acquire reference spectrum. We calculated the all optical path difference (OPD) to achieve spectral response of every wavelength sample and divided the position of reference peak to subpixel to increase the precision of spectral calibration. The spectrum of spectral calibration show two weakly responded peaks, which was validated by reference spectrum of fiber optic spectrometer. The deviation of wavelength calibration is low to establish a best spectrometer resolution. The results of spectral calibration can meet the requirements of the UV-FTIS application.

  5. High-definition Fourier transform infrared spectroscopic imaging of prostate tissue

    Science.gov (United States)

    Wrobel, Tomasz P.; Kwak, Jin Tae; Kadjacsy-Balla, Andre; Bhargava, Rohit

    2016-03-01

    Histopathology forms the gold standard for cancer diagnosis and therapy, and generally relies on manual examination of microscopic structural morphology within tissue. Fourier-Transform Infrared (FT-IR) imaging is an emerging vibrational spectroscopic imaging technique, especially in a High-Definition (HD) format, that provides the spatial specificity of microscopy at magnifications used in diagnostic surgical pathology. While it has been shown for standard imaging that IR absorption by tissue creates a strong signal where the spectrum at each pixel is a quantitative "fingerprint" of the molecular composition of the sample, here we show that this fingerprint also enables direct digital pathology without the need for stains or dyes for HD imaging. An assessment of the potential of HD imaging to improve diagnostic pathology accuracy is presented.

  6. Ultra-high resolution Fourier domain optical coherence tomography for old master paintings.

    Science.gov (United States)

    Cheung, C S; Spring, M; Liang, H

    2015-04-20

    In the last 10 years, Optical Coherence Tomography (OCT) has been successfully applied to art conservation, history and archaeology. OCT has the potential to become a routine non-invasive tool in museums allowing cross-section imaging anywhere on an intact object where there are no other methods of obtaining subsurface information. While current commercial OCTs have shown potential in this field, they are still limited in depth resolution (> 4 μm in paint and varnish) compared to conventional microscopic examination of sampled paint cross-sections (~1 μm). An ultra-high resolution fiber-based Fourier domain optical coherence tomography system with a constant axial resolution of 1.2 μm in varnish or paint throughout a depth range of 1.5 mm has been developed. While Fourier domain OCT of similar resolution has been demonstrated recently, the sensitivity roll-off of some of these systems are still significant. In contrast, this current system achieved a sensitivity roll-off that is less than 2 dB over a 1.2 mm depth range with an incident power of ~1 mW on the sample. The high resolution and sensitivity of the system makes it convenient to image thin varnish and glaze layers with unprecedented contrast. The non-invasive 'virtual' cross-section images obtained with the system show the thin varnish layers with similar resolution in the depth direction but superior clarity in the layer interfaces when compared with conventional optical microscope images of actual paint sample cross-sections obtained micro-destructively.

  7. Fourier series

    CERN Document Server

    Tolstov, Georgi P

    1962-01-01

    Richard A. Silverman's series of translations of outstanding Russian textbooks and monographs is well-known to people in the fields of mathematics, physics, and engineering. The present book is another excellent text from this series, a valuable addition to the English-language literature on Fourier series.This edition is organized into nine well-defined chapters: Trigonometric Fourier Series, Orthogonal Systems, Convergence of Trigonometric Fourier Series, Trigonometric Series with Decreasing Coefficients, Operations on Fourier Series, Summation of Trigonometric Fourier Series, Double Fourie

  8. Toward a practical X-ray Fourier holography at high resolution

    CERN Document Server

    Howells, M R; Marchesini, S; Miller, S; Spence, J C H; Weirstall, U

    2001-01-01

    We consider the theory and data analysis in Fourier-transform X-ray holography. We also report studies and experimental investigations of practical ways to generate a suitable holographic reference wave.

  9. High-Throughput Metabolic Profiling of Soybean Leaves by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    Yilmaz, Ali; Rudolph, Heather L; Hurst, Jerod J; Wood, Troy D

    2016-01-19

    As a relatively recent research field, plant metabolomics has gained increasing interest in the past few years and has been applied to answer biological questions through large-scale qualitative and quantitative analyses of the plant metabolome. The combination of sensitivity and selectivity offered by mass spectrometry (MS) for measurement of many metabolites in a single shot makes it an indispensable platform in metabolomics. In this regard, Fourier-transform ion cyclotron resonance (FTICR) has the unique advantage of delivering high mass resolving power and mass accuracy simultaneously, making it ideal for the study of complex mixtures such as plant extracts. Here we optimize soybean leaf extraction methods compatible with high-throughput reproducible MS-based metabolomics. In addition, matrix-assisted laser desorption ionization (MALDI) and direct LDI of soybean leaves are compared for metabolite profiling. The extraction method combined with electrospray (ESI)-FTICR is supported by the significant reduction of chlorophyll and its related metabolites as the growing season moves from midsummer to the autumn harvest day. To our knowledge for the first time, the use of ESI-FTICR MS and MALDI-FTICR MS is described in a complementary manner with the aim of metabolic profiling of plant leaves that have been collected at different time points during the growing season.

  10. Pulse shaping using the optical Fourier transform technique - for ultra-high-speed signal processing

    DEFF Research Database (Denmark)

    Palushani, Evarist; Oxenløwe, Leif Katsuo; Galili, Michael

    2009-01-01

    This paper reports on the generation of a 1.6 ps FWHM flat-top pulse using the optical Fourier transform technique. The pulse is validated in a 320 Gbit/s demultiplexing experiment.......This paper reports on the generation of a 1.6 ps FWHM flat-top pulse using the optical Fourier transform technique. The pulse is validated in a 320 Gbit/s demultiplexing experiment....

  11. Measuring the temporal coherence of a high harmonic generation setup employing a Fourier transform spectrometer for the VUV/XUV

    Energy Technology Data Exchange (ETDEWEB)

    Terschlüsen, J.A., E-mail: Joachim.Terschluesen@physics.uu.se; Agåker, M.; Svanqvist, M.; Plogmaker, S.; Nordgren, J.; Rubensson, J.-E.; Siegbahn, H.; Söderström, J.

    2014-12-21

    In this experiment we used an 800 nm laser to generate high-order harmonics in a gas cell filled with Argon. Of those photons, a harmonic with 42 eV was selected by using a time-preserving grating monochromator. Employing a modified Mach–Zehnder type Fourier transform spectrometer for the VUV/XUV it was possible to measure the temporal coherence of the selected photons to about 6 fs. We demonstrated that not only could this kind of measurement be performed with a Fourier transform spectrometer, but also with some spatial resolution without modifying the XUV source or the spectrometer.

  12. High-throughput biochemical fingerprinting of Saccharomyces cerevisiae by Fourier transform infrared spectroscopy.

    Directory of Open Access Journals (Sweden)

    Achim Kohler

    Full Text Available Single-channel optical density measurements of population growth are the dominant large scale phenotyping methodology for bridging the gene-function gap in yeast. However, a substantial amount of the genetic variation induced by single allele, single gene or double gene knock-out technologies fail to manifest in detectable growth phenotypes under conditions readily testable in the laboratory. Thus, new high-throughput phenotyping technologies capable of providing information about molecular level consequences of genetic variation are sorely needed. Here we report a protocol for high-throughput Fourier transform infrared spectroscopy (FTIR measuring biochemical fingerprints of yeast strains. It includes high-throughput cultivation for FTIR spectroscopy, FTIR measurements and spectral pre-treatment to increase measurement accuracy. We demonstrate its capacity to distinguish not only yeast genera, species and populations, but also strains that differ only by a single gene, its excellent signal-to-noise ratio and its relative robustness to measurement bias. Finally, we illustrated its applicability by determining the FTIR signatures of all viable Saccharomyces cerevisiae single gene knock-outs corresponding to lipid biosynthesis genes. Many of the examined knock-out strains showed distinct, highly reproducible FTIR phenotypes despite having no detectable growth phenotype. These phenotypes were confirmed by conventional lipid analysis and could be linked to specific changes in lipid composition. We conclude that the introduced protocol is robust to noise and bias, possible to apply on a very large scale, and capable of generating biologically meaningful biochemical fingerprints that are strain specific, even when strains lack detectable growth phenotypes. Thus, it has a substantial potential for application in the molecular functionalization of the yeast genome.

  13. Fourier analysis

    CERN Document Server

    Stade, Eric

    2005-01-01

    A reader-friendly, systematic introduction to Fourier analysis Rich in both theory and application, Fourier Analysis presents a unique and thorough approach to a key topic in advanced calculus. This pioneering resource tells the full story of Fourier analysis, including its history and its impact on the development of modern mathematical analysis, and also discusses essential concepts and today's applications. Written at a rigorous level, yet in an engaging style that does not dilute the material, Fourier Analysis brings two profound aspects of the discipline to the forefront: the wealth of ap

  14. Beyond Fourier.

    Science.gov (United States)

    Hoch, Jeffrey C

    2017-10-01

    Non-Fourier methods of spectrum analysis are gaining traction in NMR spectroscopy, driven by their utility for processing nonuniformly sampled data. These methods afford new opportunities for optimizing experiment time, resolution, and sensitivity of multidimensional NMR experiments, but they also pose significant challenges not encountered with the discrete Fourier transform. A brief history of non-Fourier methods in NMR serves to place different approaches in context. Non-Fourier methods reflect broader trends in the growing importance of computation in NMR, and offer insights for future software development. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Two-step ionization in non-equilibrium SF sub 6 discharges at high current density

    CERN Document Server

    Bychkov, Yu A; Lacour, B; Pasquiers, S; Puech, V; Yastremski, A

    2003-01-01

    In the pressure range 10-100 mbar, the discharge development in SF sub 6 has been investigated in the photo-triggered excitation scheme for current density in the range 10-1000 A cm sup - sup 2 and pulse duration of about 60 ns. Thanks to the homogeneity of the photo-triggered discharge, a self-consistent zero-dimensional model can be used to predict the temporal evolution of the electrical parameters. From a detailed comparison between the experimental results and the modelling predictions, evidence for the occurrence of a two-step ionization process in high current density discharges in SF sub 6 is reported and the corresponding collision cross-section is estimated. Moreover, it is shown that the amount of the two-step ionization is directly correlated to the density of the electrical charge transferred to the plasma per unit surface. This two-step ionization becomes the main source of electron multiplication whenever the transferred charge per unit surface is higher than 15 mu C cm sup - sup 2.

  16. Recombination of atomic oxygen on sintered zirconia at high temperature in non-equilibrium air plasma

    Energy Technology Data Exchange (ETDEWEB)

    Balat-Pichelin, M., E-mail: marianne.balat@promes.cnrs.fr [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES-CNRS, UPR 8521, 7 rue du four solaire, 66120 Font-Romeu Odeillo (France); Passarelli, M.; Vesel, A. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES-CNRS, UPR 8521, 7 rue du four solaire, 66120 Font-Romeu Odeillo (France)

    2010-09-01

    High temperature ceramic materials are necessary for the design of primary heat shields for future re-usable space vehicles re-entering atmospheric planet at hypersonic velocity. During the re-entry phase on earth, one of the most important phenomena occurring on the heat shield is the recombination of atomic oxygen and this phenomenon is more or less catalyzed by the material of the heat shield. This paper presents some experimental results for the recombination coefficient of atomic oxygen {gamma} based on experiments performed on the MESOX facility using optical emission spectroscopy and actinometry techniques. Experimental results on the recombination coefficient are presented for three types of sintered ZrO{sub 2} in the temperature range 900-2500 K for 200 Pa total air pressure. These three zirconia ceramics differ essentially by the chemical nature of the sintering additives (Y{sub 2}O{sub 3}, CaO or MgO). A great different behavior of the recombination coefficient versus temperature is observed according to the crystalline structure of zirconia (monoclinic and tetragonal phases) and few influence of the additive is shown.

  17. High-speed and wide bandwidth Fourier domain mode-locked wavelength swept laser with multiple SOAs.

    Science.gov (United States)

    Jeon, Min Yong; Zhang, Jun; Wang, Qiang; Chen, Zhongping

    2008-02-18

    We report on the development of a high-speed, wide bandwidth Fourier domain mode-locked (FDML) wavelength swept laser of around 1300 nm using two gain media for high-resolution and high-speed Fourier domain optical coherence tomography. The wavelength swept laser is capable of FWHM scanning range of more than 135 nm at 45.6 kHz sweeping rate. The measured axial resolution of the forward scan is 6.6 microm in air and 4.7 microm in tissue. The peak power is 11.4 mW for both the forward and backward scans. The measured system sensitivity is achieved up to 100.7 dB. We also demonstrate OCT imaging using the FDML wavelength swept laser with two semiconductor optical amplifiers.

  18. Collision cross section measurements for biomolecules within a high-resolution Fourier transform ion cyclotron resonance cell.

    Science.gov (United States)

    Mao, Lu; Chen, Yu; Xin, Yi; Chen, Yu; Zheng, Li; Kaiser, Nathan K; Marshall, Alan G; Xu, Wei

    2015-04-21

    To understand the role and function of a biomolecule in a biosystem, it is important to know both its composition and structure. Here, a mass spectrometric based approach has been proposed and applied to demonstrate that collision cross sections and high-resolution mass spectra of biomolecule ions may be obtained simultaneously by Fourier transform ion cyclotron resonance mass spectrometry. With this method, the unfolding phenomena for ubiquitin ions that possess different number of charges have been investigated, and results agree well with ion mobility measurements. In the present approach, we extend ion collision cross-section measurements to lower pressures than in prior ion cyclotron resonance (ICR)-based experiments, thereby maintaining the potentially high resolution of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS), and enabling collision cross section (CCS) measurements for high-mass biomolecules.

  19. Simulating Nonequilibrium Radiation via Orthogonal Polynomial Refinement

    Science.gov (United States)

    2015-01-07

    The complex nonequilibrium radiative simulation for high-speed flow is built on the interlocking phenomena between quantum physics , aerodynamics with...from quantum physics and transmit across the two different coordinates by a nearest neighbor search algorithm.

  20. Compression of fiber supercontinuum pulses to the Fourier-limit in a high-numerical-aperture focus

    DEFF Research Database (Denmark)

    Tu, Haohua; Liu, Yuan; Turchinovich, Dmitry

    2011-01-01

    A multiphoton intrapulse interference phase scan (MIIPS) adaptively and automatically compensates the combined phase distortion from a fiber supercontinuum source, a spatial light modulator pulse shaper, and a high-NA microscope objective, allowing Fourier-transform-limited compression...... power of 18–70mW, and a repetition rate of 76MHz, permitting the application of this source to nonlinear optical microscopy and coherently controlled microspectroscopy....

  1. Compression of fiber supercontinuum pulses to the Fourier-limit in a high-numerical-aperture focus

    OpenAIRE

    Tu, Haohua; Liu, Yuan; Turchinovich, Dmitry; Boppart, Stephen A.

    2011-01-01

    A multiphoton intrapulse interference phase scan (MIIPS) adaptively and automatically compensates the combined phase distortion from a fiber supercontinuum source, a spatial light modulator pulse shaper, and a high-NA microscope objective, allowing Fourier-transform-limited compression of the supercontinuum pulses at the focus of the objective. A second-harmonic-generation-based method is employed to independently validate the transform-limited compression. The compressed pulses at the focus ...

  2. TiO2anatase nanorods with non-equilibrium crystallographic {001} facets and their coatings exhibiting high photo-oxidation of NO gas.

    Science.gov (United States)

    Habran, Margarita; Krambrock, Klaus; Maia da Costa, M E H; Morgado, Edisson; Marinkovic, Bojan A

    2018-01-01

    Development of highly active photocatalysts is mandatory for more widespread application of this alternative environmental technology. Synthesis of photocatalysts, such as anatase TiO 2 , with more reactive, non-equilibrium, crystallographic facets is theoretically justified by a more efficient interfacial charge transfer to reactive adsorbed species, increasing quantum efficiency of photocatalyst. Air and vacuum calcinations of protonated trititanate nanotubes lead to their transformation to anatase nanorods. The nanorods synthesized by air calcination demonstrate photo-oxidation of NO gas more than three times superior to the one presented by the benchmark P-25 photocatalyst. This performance has been explained in terms of 50% higher specific surface area and, more importantly, through the predominance of more reactive, non-equilibrium, {001} crystallographic facets of the anatase nanorods. These facets present a high density of undercoordinated Ti cations, which favors adsorption of reactant species, and strained Ti-O-Ti bonds, leading to more efficient photo-oxidation reactions. Reduced Ti species, such as Ti 3+ , were not observed in the as-obtained nanorods, while reactive adsorbed molecules are scarce on the nanorods obtained through vacuum calcination. Dip-coating of TiO 2 anatase nanorods (air calcined) over soda-lime glass plates was used to prepare visible light transparent, superhydrophilic and highly adherent photocatalytic coatings with homogenously distributed nanopores.

  3. Nonequilibrium Phenomena in Plasmas

    CERN Document Server

    Sharma, A Surjalal

    2005-01-01

    The complexity of plasmas arises mainly from their inherent nonlinearity and far from equilibrium nature. The nonequilibrium behavior of plasmas is evident in the natural settings, for example, in the Earth's magnetosphere. Similarly, laboratory plasmas such as fusion bottles also have their fair share of complex behavior. Nonequilibrium phenomena are intimately connected with statistical dynamics and form one of the growing research areas in modern nonlinear physics. These studies encompass the ideas of self-organization, phase transition, critical phenomena, self-organized criticality and turbulence. This book presents studies of complexity in the context of nonequilibrium phenomena using theory, modeling, simulations, and experiments, both in the laboratory and in nature.

  4. HIGH-RESOLUTION FOURIER TRANSFORM SPECTROSCOPY OF Nb i IN THE NEAR-INFRARED

    Energy Technology Data Exchange (ETDEWEB)

    Er, A.; Güzelçimen, F.; Başar, Gö.; Öztürk, I. K. [Faculty of Science, Physics Department, Istanbul University, TR-34134 Vezneciler, Istanbul (Turkey); Tamanis, M.; Ferber, R. [Laser Centre, The University of Latvia, Rainis Boulevard 19, LV-1586 Riga (Latvia); Kröger, S., E-mail: gbasar@istanbul.edu.tr, E-mail: sophie.kroeger@htw-berlin.de [Hochschule für Technik und Wirtschaft Berlin, Wilhelminenhofstrasse 75A, D-12459 Berlin (Germany)

    2015-11-15

    In this study, a Fourier Transform spectrum of Niobium (Nb) is investigated in the near-infrared spectral range from 6000 to 12,000 cm{sup −1} (830–1660 nm). The Nb spectrum is produced using a hollow cathode discharge lamp in an argon atmosphere. Both Nb and Ar spectral lines are visible in the spectrum. A total of 110 spectral lines are assigned to the element Nb. Of these lines, 90 could be classified as transitions between known levels of atomic Nb. From these classified Nb i transitions, 27 have not been listed in literature previously. Additionally, 8 lines are classified for the first time.

  5. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    Energy Technology Data Exchange (ETDEWEB)

    Niemi, K.; O' Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l' Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2013-07-15

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  6. High-order time-splitting Hermite and Fourier spectral methods

    Science.gov (United States)

    Thalhammer, Mechthild; Caliari, Marco; Neuhauser, Christof

    2009-02-01

    In this paper, we are concerned with the numerical solution of the time-dependent Gross-Pitaevskii Equation (GPE) involving a quasi-harmonic potential. Primarily, we consider discretisations that are based on spectral methods in space and higher-order exponential operator splitting methods in time. The resulting methods are favourable in view of accuracy and efficiency; moreover, geometric properties of the equation such as particle number and energy conservation are well captured. Regarding the spatial discretisation of the GPE, we consider two approaches. In the unbounded domain, we employ a spectral decomposition of the solution into Hermite basis functions; on the other hand, restricting the equation to a sufficiently large bounded domain, Fourier techniques are applicable. For the time integration of the GPE, we study various exponential operator splitting methods of convergence orders two, four, and six. Our main objective is to provide accuracy and efficiency comparisons of exponential operator splitting Fourier and Hermite pseudospectral methods for the time evolution of the GPE. Furthermore, we illustrate the effectiveness of higher-order time-splitting methods compared to standard integrators in a long-term integration.

  7. Fourier Series

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Fourier Series. The Mathematics of Periodic Phenomena. The author received his. Ph.D from Princeton. University in 1987. After spending several years at. TIFR Centre, Bangalore, he is currently with the. Indian Statistical Institute,. Bangalore. His research interests are in harmonic analysis and partial.

  8. High-resolution wave-theory-based ultrasound reflection imaging using the split-step fourier and globally optimized fourier finite-difference methods

    Science.gov (United States)

    Huang, Lianjie

    2013-10-29

    Methods for enhancing ultrasonic reflection imaging are taught utilizing a split-step Fourier propagator in which the reconstruction is based on recursive inward continuation of ultrasonic wavefields in the frequency-space and frequency-wave number domains. The inward continuation within each extrapolation interval consists of two steps. In the first step, a phase-shift term is applied to the data in the frequency-wave number domain for propagation in a reference medium. The second step consists of applying another phase-shift term to data in the frequency-space domain to approximately compensate for ultrasonic scattering effects of heterogeneities within the tissue being imaged (e.g., breast tissue). Results from various data input to the method indicate significant improvements are provided in both image quality and resolution.

  9. New Atomic Data for Doubly Ionized Iron Group Atoms by High Resolution UV Fourier Transform Spectroscopy

    Science.gov (United States)

    Smith, Peter L.; Pickering, Juliet C.; Thorne, A. P.

    2002-01-01

    Currently available laboratory spectroscopic data of doubly ionized iron-group element were obtained about 50 years ago using spectrographs of modest dispersion, photographic plates, and eye estimates of intensities. The accuracy of the older wavelength data is about 10 mAngstroms at best, whereas wavelengths are now needed to an accuracy of 1 part in 10(exp 6) to 10(exp 7) (0.2 to 2 mAngstroms at 2000 Angstroms). The Fourier transform (FT) spectroscopy group at Imperial College, London, and collaborators at the Harvard College Observatory have used a unique VUV FT spectrometer in a program focussed on improving knowledge of spectra of many neutral and singly and doubly ionized, astrophysically important, iron group elements. Spectra of Fe II and Fe III have been recorded at UV and VUV wavelengths with signal-to-noise ratios of several hundred for the stronger lines. Wavelengths and energy levels for Fe III are an order of magnitude more accurate than previous work; analysis is close to completion. f-values for Fe II have been published.

  10. Nonequilibrium topological phase transitions in two-dimensional optical lattices

    Science.gov (United States)

    Nakagawa, Masaya; Kawakami, Norio

    2014-01-01

    Recently, concepts of topological phases of matter are extended to nonequilibrium systems, especially periodically driven systems. In this paper, we construct an example which shows nonequilibrium topological phase transitions using ultracold fermions in optical lattices. We show that the Rabi oscillation has the possibility to induce nonequilibrium topological phases which are classified into time-reversal-invariant topological insulators for a two-orbital model of alkaline-earth-metal atoms. Furthermore, we study the nonequilibrium topological phases using time-dependent Schrieffer-Wolff-type perturbation theory, and we obtain an analytical expression to describe the topological phase transitions from a high-frequency limit of external driving fields.

  11. Atomic gas temperature in a nonequilibrium high-intensity discharge lamp determined from the red wing of the resonance mercury line 254 nm

    Energy Technology Data Exchange (ETDEWEB)

    Drakakis, E. [Technological Educational Institute, Department of Electrical Engineering, 71004 Heraklion (Greece); Karabourniotis, D. [Institute of Plasma Physics, Department of Physics, University of Crete, 71003 Heraklion (Greece)

    2012-09-01

    For developing low-wattage high intensity discharge (HID) lamps, a better understanding of the relatively unexplored nonequilibrium phenomena is essential. This needs interpretation of diagnostic results by methods free from equilibrium assumptions. In this paper, the atomic temperature is determined from the simulation of a quasistatic broadened resonance line by distinguishing between atomic temperature and excitation temperature in the equation of radiative transfer. The proposed method is applied to the red wing of the resonance mercury line 254 nm emitted from a HID lamp working on ac. The experimental results show severe deviation from local thermodynamic equilibrium. More than one thousand degrees difference was obtained between atomic and electron temperatures at the maximum current phase.

  12. Nonequilibrium statistical physics

    CERN Document Server

    Röpke, Gerd

    2013-01-01

    Authored by one of the top theoretical physicists in Germany, and a well-known authority in the field, this is the only coherent presentation of the subject suitable for masters and PhD students, as well as postdocs in physics and related disciplines.Starting from a general discussion of the nonequilibrium state, different standard approaches such as master equations, and kinetic and linear response theory, are derived after special assumptions. This allows for an insight into the problems of nonequilibrium physics, a discussion of the limits, and suggestions for improvements. Applications

  13. The Statistical Dynamics of Nonequilibrium Control

    Science.gov (United States)

    Rotskoff, Grant Murray

    Living systems, even at the scale of single molecules, are constantly adapting to changing environmental conditions. The physical response of a nanoscale system to external gradients or changing thermodynamic conditions can be chaotic, nonlinear, and hence difficult to control or predict. Nevertheless, biology has evolved systems that reliably carry out the cell's vital functions efficiently enough to ensure survival. Moreover, the development of new experimental techniques to monitor and manipulate single biological molecules has provided a natural testbed for theoretical investigations of nonequilibrium dynamics. This work focuses on developing paradigms for both understanding the principles of nonequilibrium dynamics and also for controlling such systems in the presence of thermal fluctuations. Throughout this work, I rely on a perspective based on two central ideas in nonequilibrium statistical mechanics: large deviation theory, which provides a formalism akin to thermodynamics for nonequilibrium systems, and the fluctuation theorems which identify time symmetry breaking with entropy production. I use the tools of large deviation theory to explore concepts like efficiency and optimal coarse-graining in microscopic dynamical systems. The results point to the extreme importance of rare events in nonequilibrium dynamics. In the context of rare dynamical events, I outline a formal approach to predict efficient control protocols for nonequilibrium systems and develop computational tools to solve the resulting high dimensional optimization problems. The final chapters of this work focus on applications to self-assembly dynamics. I show that the yield of desired structures can be enhanced by driving a system away from equilibrium, using analysis inspired by the theory of the hydrophobic effect. Finally, I demonstrate that nanoscale, protein shells can be modeled and controlled to robustly produce monodisperse, nonequilibrium structures strikingly similar to the

  14. All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2016-01-01

    We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

  15. Relaxation, turbulence, and non-equilibrium dynamics of matter fields. From quantum fluids to high-energy physics RETUNE. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    The following topics were dealt with: Superfluidity and quantum turbulence, quantum vortices and their reconnections, quantum hydrodynamics and turbulence in Bose-Einstein condensates, phase transitions in turbulence, perfect fluidity in relativistic heavy ion collisions, off-shell dynamical approach for relativistic heavy ion collisions, turbulence in the early universe, a superfluid universe, superfluidity and hydrodynamic excitations in out-of-equilibrium polariton condensates, two-dimensional quantum turbulence in Bose-Einstein condensates, nonequilibrium Bose gases with classical fields, turbulence in superfluid {sup 4}He in the T=0 limit, condensation, superfluidity and lasing of coupled light-matter systems, tachyon condensation in Bose-Einstein condensates, Bose-Einstein condensation of magnons in superfluid {sup 3}He-B and its application to vortex studies, wave turbulence in Bose-Einstein condensates, instability in an expanding non-Abelian system, nonabelian plasma instabilities, quantum turbulence in an atomic trapped superfluid, nonthermal fixed points and superfluid turbulence, macroscopic quantum tunneling in Bose-Einstein condensates, pair coherence in many-body quenches, sound waves in non-stationary media, thermalization induced by chaotic behavior in classical Yang-Mills dynamics, chiral superfluidity of the quark-gluon plasma, functional renormalization-group flow for Burger's equation, anomalous scaling in the random-force-driven Burger's equation, Kadanoff-Baym approach to thermalization, many-body resonant tunneling in the Wannier system, generalized Boltzmann equation in ultrasoft region, dynamical view of the Schwinger mechanism, parity violation in hydrogen and squeezing. (HSI)

  16. Nonequilibrium thermodynamics of nucleation

    NARCIS (Netherlands)

    Schweizer, M.; Sagis, L.M.C.

    2014-01-01

    We present a novel approach to nucleation processes based on the GENERIC framework (general equation for the nonequilibrium reversible-irreversible coupling). Solely based on the GENERIC structure of time-evolution equations and thermodynamic consistency arguments of exchange processes between a

  17. Nonequilibrium thermal entanglement

    OpenAIRE

    Quiroga, Luis; Rodriguez, Ferney J.; Ramirez, Maria E.; Paris, Roberto

    2006-01-01

    Results on heat current, entropy production rate and entanglement are reported for a quantum system coupled to two different temperature heat reservoirs. By applying a temperature gradient, different quantum states can be found with exactly the same amount of entanglement but different purity degrees and heat currents. Furthermore, a nonequilibrium enhancement-suppression transition behavior of the entanglement is identified.

  18. Fourier Transform Mass Spectrometry.

    Science.gov (United States)

    Gross, Michael L.; Rempel, Don L.

    1984-01-01

    Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

  19. Component analyses of urinary nanocrystallites of uric acid stone formers by combination of high-resolution transmission electron microscopy, fast Fourier transformation, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming

    2015-06-01

    This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites.

  20. From regular text to artistic writing and artworks: Fourier statistics of images with low and high aesthetic appeal

    Directory of Open Access Journals (Sweden)

    Tamara eMelmer

    2013-04-01

    Full Text Available The spatial characteristics of letters and their influence on readability and letter identification have been intensely studied during the last decades. There have been few studies, however, on statistical image properties that reflect more global aspects of text, for example properties that may relate to its aesthetic appeal. It has been shown that natural scenes and a large variety of visual artworks possess a scale-invariant Fourier power spectrum that falls off linearly with increasing frequency in log-log plots. We asked whether images of text share this property. As expected, the Fourier spectrum of images of regular typed or handwritten text is highly anisotropic, i.e. the spectral image properties in vertical, horizontal and oblique orientations differ. Moreover, the spatial frequency spectra of text images are not scale invariant in any direction. The decline is shallower in the low-frequency part of the spectrum for text than for aesthetic artworks, whereas, in the high-frequency part, it is steeper. These results indicate that, in general, images of regular text contain less global structure (low spatial frequencies relative to fine detail (high spatial frequencies than images of aesthetics artworks. Moreover, we studied images of text with artistic claim (ornate print and calligraphy and ornamental art. For some measures, these images assume average values intermediate between regular text and aesthetic artworks. Finally, to answer the question of whether the statistical properties measured by us are universal amongst humans or are subject to intercultural differences, we compared images from three different cultural backgrounds (Western, East Asian and Arabic. Results for different categories (regular text, aesthetic writing, ornamental art and fine art were similar across cultures.

  1. From regular text to artistic writing and artworks: Fourier statistics of images with low and high aesthetic appeal

    Science.gov (United States)

    Melmer, Tamara; Amirshahi, Seyed A.; Koch, Michael; Denzler, Joachim; Redies, Christoph

    2013-01-01

    The spatial characteristics of letters and their influence on readability and letter identification have been intensely studied during the last decades. There have been few studies, however, on statistical image properties that reflect more global aspects of text, for example properties that may relate to its aesthetic appeal. It has been shown that natural scenes and a large variety of visual artworks possess a scale-invariant Fourier power spectrum that falls off linearly with increasing frequency in log-log plots. We asked whether images of text share this property. As expected, the Fourier spectrum of images of regular typed or handwritten text is highly anisotropic, i.e., the spectral image properties in vertical, horizontal, and oblique orientations differ. Moreover, the spatial frequency spectra of text images are not scale-invariant in any direction. The decline is shallower in the low-frequency part of the spectrum for text than for aesthetic artworks, whereas, in the high-frequency part, it is steeper. These results indicate that, in general, images of regular text contain less global structure (low spatial frequencies) relative to fine detail (high spatial frequencies) than images of aesthetics artworks. Moreover, we studied images of text with artistic claim (ornate print and calligraphy) and ornamental art. For some measures, these images assume average values intermediate between regular text and aesthetic artworks. Finally, to answer the question of whether the statistical properties measured by us are universal amongst humans or are subject to intercultural differences, we compared images from three different cultural backgrounds (Western, East Asian, and Arabic). Results for different categories (regular text, aesthetic writing, ornamental art, and fine art) were similar across cultures. PMID:23554592

  2. Nonequilibrium molecular dynamics theory, algorithms and applications

    CERN Document Server

    Todd, Billy D

    2017-01-01

    Written by two specialists with over twenty-five years of experience in the field, this valuable text presents a wide range of topics within the growing field of nonequilibrium molecular dynamics (NEMD). It introduces theories which are fundamental to the field - namely, nonequilibrium statistical mechanics and nonequilibrium thermodynamics - and provides state-of-the-art algorithms and advice for designing reliable NEMD code, as well as examining applications for both atomic and molecular fluids. It discusses homogenous and inhomogenous flows and pays considerable attention to highly confined fluids, such as nanofluidics. In addition to statistical mechanics and thermodynamics, the book covers the themes of temperature and thermodynamic fluxes and their computation, the theory and algorithms for homogenous shear and elongational flows, response theory and its applications, heat and mass transport algorithms, applications in molecular rheology, highly confined fluids (nanofluidics), the phenomenon of slip and...

  3. Equilibrium sampling by reweighting nonequilibrium simulation trajectories.

    Science.gov (United States)

    Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin

    2016-03-01

    Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.

  4. High-order modulation on a single discrete eigenvalue for optical communications based on nonlinear Fourier transform.

    Science.gov (United States)

    Gui, Tao; Lu, Chao; Lau, Alan Pak Tao; Wai, P K A

    2017-08-21

    In this paper, we experimentally investigate high-order modulation over a single discrete eigenvalue under the nonlinear Fourier transform (NFT) framework and exploit all degrees of freedom for encoding information. For a fixed eigenvalue, we compare different 4 bit/symbol modulation formats on the spectral amplitude and show that a 2-ring 16-APSK constellation achieves optimal performance. We then study joint spectral phase, spectral magnitude and eigenvalue modulation and found that while modulation on the real part of the eigenvalue induces pulse timing drift and leads to neighboring pulse interactions and nonlinear inter-symbol interference (ISI), it is more bandwidth efficient than modulation on the imaginary part of the eigenvalue in practical settings. We propose a spectral amplitude scaling method to mitigate such nonlinear ISI and demonstrate a record 4 GBaud 16-APSK on the spectral amplitude plus 2-bit eigenvalue modulation (total 6 bit/symbol at 24 Gb/s) transmission over 1000 km.

  5. Real-time in vitro Fourier ptychographic microscopy for high resolution wide field of view phase imaging

    CERN Document Server

    Tian, Lei; Yeh, Li-Hao; Chen, Michael; Waller, Laura

    2015-01-01

    For centuries, microscopes have had to trade field of view (FOV) for resolution. Recently, a new computational imaging technique, termed Fourier ptychographic microscopy (FPM), circumvents this limit in order to capture gigapixel-scale images having both wide FOV and high resolution. FPM has enormous potential for revolutionizing biomedical microscopy; however, it has until now been limited to fixed samples, since acquisition time is on the order of minutes. Live biological samples are continuously evolving on multiple spatial and temporal scales, which can cause motion blur. Here, we present a Fast FPM method to achieve sub-second capture times for FPM results with 0.8 NA resolution across a 4x objective's FOV. We demonstrate the first FPM quantitative phase results for both growing and confluent in vitro cell cultures. Experiments capture real-time videos of HeLa and human mammary epithelial (MCF10A) cell division and migration and subcellular dynamical phenomena in adult rat neural stem cells.

  6. Design and performance of a soft-x-ray interferometer for ultra-high-resolution fourier transform spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moler, E.J.; Hussain, Z.; Duarte, R.M.; Howells, M.R. [Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    A Fourier Transform Soft X-ray spectrometer (FT-SX) has been designed and is under construction for the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory as a branch of beamline 9.3.2. The spectrometer is a novel soft x-ray interferometer designed for ultra-high resolution (theoretical resolving power E/{delta}E{approximately}10{sup 6}) spectroscopy in the photon energy region of 60-120 eV. This instrument is expected to provide experimental results which sensitively test models of correlated electron processes in atomic and molecular physics. The design criteria and consequent technical challenges posed by the short wavelengths of x-rays and desired resolving power are discussed. The fundamental and practical aspects of soft x-ray interferometry are also explored.

  7. Multimode vibration analysis with high-speed TV holography and a spatiotemporal 3D Fourier transform method.

    Science.gov (United States)

    Trillo, Cristina; Doval, Angel F; Mendoza-Santoyo, Fernando; Pérez-López, Carlos; de la Torre-Ibarra, Manuel; Deán, J Luis

    2009-09-28

    The combination of a high-speed TV holography system and a 3D Fourier-transform data processing is proposed for the analysis of multimode vibrations in plates. The out-of-plane displacement of the object under generic vibrational excitation is resolved in time by the fast acquisition rate of a high-speed camera, and recorded in a sequence of interferograms with spatial carrier. A full-field temporal history of the multimode vibration is thus obtained. The optical phase of the interferograms is extracted and subtracted from the phase of a reference state to yield a sequence of optical phase-change maps. Each map represents the change undergone by the object between any given state and the reference state. The sequence of maps is a 3D array of data (two spatial dimensions plus time) that is processed with a 3D Fourier-transform algorithm. The individual vibration modes are separated in the 3D frequency space due to their different vibration frequencies and, to a lesser extent, to the different spatial frequencies of the mode shapes. The contribution of each individual mode (or indeed the superposition of several modes) to the dynamic behaviour of the object can then be separated by means of a bandpass filter (or filters). The final output is a sequence of complex-valued maps that contain the full-field temporal history of the selected mode (or modes) in terms of its mechanical amplitude and phase. The proof-of-principle of the technique is demonstrated with a rectangular, fully clamped, thin metal plate vibrating simultaneously in several of its natural resonant frequencies under white-noise excitation.

  8. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav

    2009-09-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

  9. Small fields: nonequilibrium radiation dosimetry.

    Science.gov (United States)

    Das, Indra J; Ding, George X; Ahnesjö, Anders

    2008-01-01

    Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields > or =4 x 4 cm2, this can result in significant uncertainty in the accuracy of clinical dosimetry. The dosimetry of small fields is challenging due to nonequilibrium conditions created as a consequence of the secondary electron track lengths and the source size projected through the collimating system that are comparable to the treatment field size. It is further complicated by the prolonged electron tracks in the presence of low-density inhomogeneities. Also, radiation detectors introduced into such fields usually perturb the level of disequilibrium. Hence, the dosimetric accuracy previously achieved for standard radiotherapy applications is at risk for both absolute and relative dose determination. This article summarizes the present knowledge and gives an insight into the future procedures to handle the nonequilibrium radiation dosimetry problems. It is anticipated that new miniature detectors with controlled perturbations and corrections will be available to meet the demand for accurate measurements. It is also expected that the Monte Carlo techniques will increasingly be used in assessing the accuracy, verification, and calculation of dose, and will aid perturbation calculations of detectors used in small and highly conformal radiation beams. rican Association of Physicists in Medicine.

  10. Fourier-Hermite communications; where Fourier meets Hermite

    NARCIS (Netherlands)

    Korevaar, C.W.; Kokkeler, Andre B.J.; de Boer, Pieter-Tjerk; Smit, Gerardus Johannes Maria

    A new signal set, based on the Fourier and Hermite signal bases, is introduced. It combines properties of the Fourier basis signals with the perfect time-frequency localization of the Hermite functions. The signal set is characterized by both a high spectral efficiency and good time-frequency

  11. Immersed boundary smooth extension: A high-order method for solving PDE on arbitrary smooth domains using Fourier spectral methods

    Science.gov (United States)

    Stein, David B.; Guy, Robert D.; Thomases, Becca

    2016-01-01

    The Immersed Boundary method is a simple, efficient, and robust numerical scheme for solving PDE in general domains, yet it only achieves first-order spatial accuracy near embedded boundaries. In this paper, we introduce a new high-order numerical method which we call the Immersed Boundary Smooth Extension (IBSE) method. The IBSE method achieves high-order accuracy by smoothly extending the unknown solution of the PDE from a given smooth domain to a larger computational domain, enabling the use of simple Cartesian-grid discretizations (e.g. Fourier spectral methods). The method preserves much of the flexibility and robustness of the original IB method. In particular, it requires minimal geometric information to describe the boundary and relies only on convolution with regularized delta-functions to communicate information between the computational grid and the boundary. We present a fast algorithm for solving elliptic equations, which forms the basis for simple, high-order implicit-time methods for parabolic PDE and implicit-explicit methods for related nonlinear PDE. We apply the IBSE method to solve the Poisson, heat, Burgers', and Fitzhugh-Nagumo equations, and demonstrate fourth-order pointwise convergence for Dirichlet problems and third-order pointwise convergence for Neumann problems.

  12. Superluminal electromagnetic solitons in nonequilibrium media

    Energy Technology Data Exchange (ETDEWEB)

    Sazonov, Sergei V [Kaliningrad State Technical University, Kaliningrad (Russian Federation)

    2001-06-30

    The possibility of stable faster-than-light propagation of ultimately short (without high-frequency carrier) electromagnetic solitons, breathers, and nonresonant envelope solitons is discussed based on the simple model of two-component nonequilibrium media undergoing two-level quantum transitions with widely differing eigenfrequencies. (methodological notes)

  13. Statistical mechanics of nonequilibrium liquids

    CERN Document Server

    Evans, Denis J; Craig, D P; McWeeny, R

    1990-01-01

    Statistical Mechanics of Nonequilibrium Liquids deals with theoretical rheology. The book discusses nonlinear response of systems and outlines the statistical mechanical theory. In discussing the framework of nonequilibrium statistical mechanics, the book explains the derivation of a nonequilibrium analogue of the Gibbsian basis for equilibrium statistical mechanics. The book reviews the linear irreversible thermodynamics, the Liouville equation, and the Irving-Kirkwood procedure. The text then explains the Green-Kubo relations used in linear transport coefficients, the linear response theory,

  14. High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging of human tissue sections towards improving pathology.

    Science.gov (United States)

    Sreedhar, Hari; Varma, Vishal K; Nguyen, Peter L; Davidson, Bennett; Akkina, Sanjeev; Guzman, Grace; Setty, Suman; Kajdacsy-Balla, Andre; Walsh, Michael J

    2015-01-21

    High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging is an emerging approach to obtain detailed images that have associated biochemical information. FT-IR imaging of tissue is based on the principle that different regions of the mid-infrared are absorbed by different chemical bonds (e.g., C=O, C-H, N-H) within cells or tissue that can then be related to the presence and composition of biomolecules (e.g., lipids, DNA, glycogen, protein, collagen). In an FT-IR image, every pixel within the image comprises an entire Infrared (IR) spectrum that can give information on the biochemical status of the cells that can then be exploited for cell-type or disease-type classification. In this paper, we show: how to obtain IR images from human tissues using an FT-IR system, how to modify existing instrumentation to allow for high-definition imaging capabilities, and how to visualize FT-IR images. We then present some applications of FT-IR for pathology using the liver and kidney as examples. FT-IR imaging holds exciting applications in providing a novel route to obtain biochemical information from cells and tissue in an entirely label-free non-perturbing route towards giving new insight into biomolecular changes as part of disease processes. Additionally, this biochemical information can potentially allow for objective and automated analysis of certain aspects of disease diagnosis.

  15. Diverse high-risk B2 and D Escherichia coli clones depicted by Fourier Transform Infrared Spectroscopy

    Science.gov (United States)

    Sousa, Clara; Novais, Ângela; Magalhães, Ana; Lopes, João; Peixe, Luísa

    2013-11-01

    We aimed to develop a reliable method based on Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) to discriminate Escherichia coli clones from B2(n = 9) and D(n = 13) phylogenetic groups. Eighty-eight E. coli isolates belonging to phylogenetic groups B2(n = 39) and D(n = 49), including particularly widespread high risk clones or clonal complexes (HiRCC) ST131, ST69, ST393 and ST405 were studied. Spectra were analysed by unsupervised (hierarchical cluster analysis-HCA) and supervised methods (soft independent modelling of class analogy-SIMCA and partial least square discriminant analysis-PLSDA). B2-ST131 isolates were discriminated from B2 non-ST131 and D phylogroup isolates (ST69, ST393, ST405) by HCA, SIMCA and PLSDA. D-ST69, D-ST393 and D-ST405 isolates were also distinguished from each other and from other STs from phylogroup D by the three methods. We demonstrate that FTIR-ATR coupled with chemometrics is a reliable and alternative method to accurately discriminate particular E. coli clones. Its validation towards an application at a routine basis could revolutionize high-throughput bacterial typing.

  16. High-definition Fourier Transform Infrared (FT-IR) Spectroscopic Imaging of Human Tissue Sections towards Improving Pathology

    Science.gov (United States)

    Nguyen, Peter L.; Davidson, Bennett; Akkina, Sanjeev; Guzman, Grace; Setty, Suman; Kajdacsy-Balla, Andre; Walsh, Michael J.

    2015-01-01

    High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging is an emerging approach to obtain detailed images that have associated biochemical information. FT-IR imaging of tissue is based on the principle that different regions of the mid-infrared are absorbed by different chemical bonds (e.g., C=O, C-H, N-H) within cells or tissue that can then be related to the presence and composition of biomolecules (e.g., lipids, DNA, glycogen, protein, collagen). In an FT-IR image, every pixel within the image comprises an entire Infrared (IR) spectrum that can give information on the biochemical status of the cells that can then be exploited for cell-type or disease-type classification. In this paper, we show: how to obtain IR images from human tissues using an FT-IR system, how to modify existing instrumentation to allow for high-definition imaging capabilities, and how to visualize FT-IR images. We then present some applications of FT-IR for pathology using the liver and kidney as examples. FT-IR imaging holds exciting applications in providing a novel route to obtain biochemical information from cells and tissue in an entirely label-free non-perturbing route towards giving new insight into biomolecular changes as part of disease processes. Additionally, this biochemical information can potentially allow for objective and automated analysis of certain aspects of disease diagnosis. PMID:25650759

  17. Potential of dynamically harmonized Fourier transform ion cyclotron resonance cell for high-throughput metabolomics fingerprinting: control of data quality.

    Science.gov (United States)

    Habchi, Baninia; Alves, Sandra; Jouan-Rimbaud Bouveresse, Delphine; Appenzeller, Brice; Paris, Alain; Rutledge, Douglas N; Rathahao-Paris, Estelle

    2018-01-01

    Due to the presence of pollutants in the environment and food, the assessment of human exposure is required. This necessitates high-throughput approaches enabling large-scale analysis and, as a consequence, the use of high-performance analytical instruments to obtain highly informative metabolomic profiles. In this study, direct introduction mass spectrometry (DIMS) was performed using a Fourier transform ion cyclotron resonance (FT-ICR) instrument equipped with a dynamically harmonized cell. Data quality was evaluated based on mass resolving power (RP), mass measurement accuracy, and ion intensity drifts from the repeated injections of quality control sample (QC) along the analytical process. The large DIMS data size entails the use of bioinformatic tools for the automatic selection of common ions found in all QC injections and for robustness assessment and correction of eventual technical drifts. RP values greater than 106 and mass measurement accuracy of lower than 1 ppm were obtained using broadband mode resulting in the detection of isotopic fine structure. Hence, a very accurate relative isotopic mass defect (RΔm) value was calculated. This reduces significantly the number of elemental composition (EC) candidates and greatly improves compound annotation. A very satisfactory estimate of repeatability of both peak intensity and mass measurement was demonstrated. Although, a non negligible ion intensity drift was observed for negative ion mode data, a normalization procedure was easily applied to correct this phenomenon. This study illustrates the performance and robustness of the dynamically harmonized FT-ICR cell to perform large-scale high-throughput metabolomic analyses in routine conditions. Graphical abstract Analytical performance of FT-ICR instrument equipped with a dynamically harmonized cell.

  18. Highly reproducible laser beam scanning device for an internal source laser desorption microprobe Fourier transform mass spectrometer

    Science.gov (United States)

    Scott, Jill R.; Tremblay, Paul L.

    2002-03-01

    Traditionally, mass spectrometry has relied on manipulating the sample target to provide scanning capabilities for laser desorption microprobes. This has been problematic for an internal source laser desorption Fourier transform mass spectrometer (LD-FTMS) because of the high magnetic field (7 Tesla) and geometric constraints of the superconducting magnet bore. To overcome these limitations, we have implemented a unique external laser scanning mechanism for an internal source LD-FTMS. This mechanism provides adjustable resolution enhancement so that the spatial resolution at the target is not limited to that of the stepper motors at the light source (˜5 μm/step). The spatial resolution is now limited by the practical optical diffraction limit of the final focusing lens. The scanning mechanism employs a virtual source that is wavelength independent up to the final focusing lens, which can be controlled remotely to account for focal length dependence on wavelength. A binary index provides an automatic alignment feature. The virtual source is located ˜9 ft from the sample; therefore, it is completely outside of the vacuum system and beyond the 50 G line of the fringing magnetic field. To eliminate reproducibility problems associated with vacuum pump vibrations, we have taken advantage of the magnetic field inherent to the FTMS to utilize Lenz's law for vibrational dampening. The LD-FTMS microprobe has exceptional reproducibility, which enables successive mapping sequences for depth-profiling studies.

  19. Retrieval of Atmospheric CO2 and CH4 Variations Using Ground-Based High Resolution Fourier Transform Infrared Spectra

    Directory of Open Access Journals (Sweden)

    Tian Yuan

    2015-01-01

    Full Text Available High resolution Fourier transform near IR solar spectra are used to estimate the column-averaged dry-air mole fraction (DMF of CO2 and CH4 variations in the atmosphere. The preliminary retrieval results for CO2 and CH4 variations in the area of Hefei, China, are presented, and the underlying error sources are also analyzed. Both a forward analysis and an inversion algorithm are included in the retrieval. The forward analysis uses the modeled atmospheric transmittance to line-by-line (LBL convolute the instrument line shape function. The influences of the temperature, pressure, humidity, and a priori gases are considered in the atmospheric transmittance model. The inversion algorithm is based on the nonlinear iterative and nonlinear least squares spectral fitting, which is used to obtain VCDCO2 and VCDCH4 (which represent vertical column density of CO2 and CH4, resp.. Furthermore, the VCDO2 is also retrieved for converting the VCDs into DMFs. DMFs are final products of data analysis. The inversion results can clearly resolve the tiny variations of CO2 and CH4 under strong atmospheric background. Spectral fitting residuals for both VCDCO2 and VCDCH4 are less than 0.5%. Finally, CO2 and CH4 diurnal variations are investigated based on a typical observation. About 2 ppm amplitude for DMFCO2 diurnal variations and less than 15 ppb amplitude for DMFCH4 are observed.

  20. Random fractional Fourier transform.

    Science.gov (United States)

    Liu, Zhengjun; Liu, Shutian

    2007-08-01

    We propose a novel random fractional Fourier transform by randomizing the transform kernel function of the conventional fractional Fourier transform. The random fractional Fourier transform inherits the excellent mathematical properties from the fractional Fourier transform and can be easily implemented in optics. As a primary application the random fractional Fourier transform can be directly used in optical image encryption and decryption. The double phase encoding image encryption schemes can thus be modeled with cascaded random fractional Fourier transformers.

  1. Non-equilibrium thermodynamics

    CERN Document Server

    De Groot, Sybren Ruurds

    1984-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  2. High-resolution Fourier-Domain Optical Coherence Tomography and Microperimetric Findings After Macula-off Retinal Detachment Repair

    Science.gov (United States)

    Smith, Allison J.; Telander, David G.; Zawadzki, Robert J.; Choi, Stacey S.; Morse, Lawrence S.; Werner, John S.; Park, Susanna S.

    2009-01-01

    Objective To evaluate the morphologic changes in the macula of subjects with repaired macula-off retinal detachment (RD) using high-resolution Fourier-domain optical coherence tomography (FD OCT) and to perform functional correlation in a subset of patients using microperimetry (MP-1). Design Prospective observational case series. Participants Seventeen eyes from 17 subjects who had undergone anatomically successful repair for macula-off, rhegmatogenous RD at least 3 months earlier and without visually significant maculopathy on funduscopy. Methods FD OCT with axial and transverse resolution of 4.5 μm and 10 to 15 μm, respectively, was used to obtain rapid serial B-scans of the macula, which were compared with that from Stratus OCT. The FD OCT B-scans were used to create a 3-dimensional volume, from which en face C-scans were created. Among 11 patients, MP-1 was performed to correlate morphologic changes with visual function. Main Outcome Measures Stratus OCT scans, FD OCT scans, and MP-1 data. Results Stratus OCT and FD OCT images of the macula were obtained 3 to 30 months (mean 7 months) postoperatively in all eyes. Although Stratus OCT revealed photoreceptor disruption in 2 eyes (12%), FD OCT showed photoreceptor disruption in 13 eyes (76%). This difference was statistically significant (Pmacula-off RD repair is a common abnormality in the macula that is detected better with FD OCT than Stratus OCT. A good correlation between MP-1 abnormality and presence of photoreceptor disruption or subretinal fluid on FD OCT demonstrates that these anatomic abnormalities contribute to decreased visual function after successful repair. PMID:18672289

  3. The nonequilibrium beam plasma

    Science.gov (United States)

    Skvortsov, V. A.

    1996-10-01

    The kinetics and the heating of nonequilibrium plasma, formed as a result of injection of intensive relativistic (or subrelativistic) electron or proton beams in the atomic-molecular gas (nitrogen or air with water vapor) at different pressures (from 0.1-10 atm) have been investigated numerically by using the mathematical model “SKIF” which was developed by the author 15 years ago. More than 200 plasma-chemical reactions and elementary processes are taken into consideration, including the action of “non-Maxwell” electrons of the cascade, formed in the ionization of the molecules by the beam particles. For the description of the deviation of energy distribution of such electrons from the equilibrium distribution, a simplified analytical model was used, with the help of which one can calculate the energy spectrum of the cascade electrons with satisfactory precision. This essentially reduces the calculating expenditure.

  4. Non-equilibrium Economics

    Directory of Open Access Journals (Sweden)

    Katalin Martinás

    2007-02-01

    Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.

  5. High-speed, high-resolution Fourier-domain optical coherence tomography system for retinal imaging in the 1060 nm wavelength region.

    Science.gov (United States)

    Puvanathasan, Prabakar; Forbes, Peter; Ren, Zhao; Malchow, Doug; Boyd, Shelley; Bizheva, Kostadinka

    2008-11-01

    A high-speed (47,000 A-scans/s), ultrahigh axial resolution Fourier domain optical coherence tomography (OCT) system for retinal imaging at approximately 1060 nm, based on a 1024 pixel linear array, 47 kHz readout rate InGaAs camera is presented. When interfaced with a custom superluminescent diode (lambda(c) = 1020 nm, Deltalambda = 108 nm, Pout = 9 mW), the system provides 3.3 microm axial OCT resolution at the surface of biological tissue, approximately 4.5 microm in vivo in rat retina, approximately 5.7 microm in vivo in human retina, and 110 dB sensitivity for 870 microW incident power and 21 mus integration time. Retinal tomograms acquired in vivo from a human volunteer and a rat animal model show clear visualization of all intraretinal layer and increased penetration into the choroid.

  6. Definition of Nonequilibrium Entropy of General Systems

    OpenAIRE

    Mei, Xiaochun

    1999-01-01

    The definition of nonequilibrium entropy is provided for the general nonequilibrium processes by connecting thermodynamics with statistical physics, and the principle of entropy increment in the nonequilibrium processes is also proved in the paper. The result shows that the definition of nonequilibrium entropy is not unique.

  7. Improving high-altitude emp modeling capabilities by using a non-equilibrium electron swarm model to monitor conduction electron evolution

    Science.gov (United States)

    Pusateri, Elise Noel

    An Electromagnetic Pulse (EMP) can severely disrupt the use of electronic devices in its path causing a significant amount of infrastructural damage. EMP can also cause breakdown of the surrounding atmosphere during lightning discharges. This makes modeling EMP phenomenon an important research effort in many military and atmospheric physics applications. EMP events include high-energy Compton electrons or photoelectrons that ionize air and produce low energy conduction electrons. A sufficient number of conduction electrons will damp or alter the EMP through conduction current. Therefore, it is important to understand how conduction electrons interact with air in order to accurately predict the EMP evolution and propagation in the air. It is common for EMP simulation codes to use an equilibrium ohmic model for computing the conduction current. Equilibrium ohmic models assume the conduction electrons are always in equilibrium with the local instantaneous electric field, i.e. for a specific EMP electric field, the conduction electrons instantaneously reach steady state without a transient process. An equilibrium model will work well if the electrons have time to reach their equilibrium distribution with respect to the rise time or duration of the EMP. If the time to reach equilibrium is comparable or longer than the rise time or duration of the EMP then the equilibrium model would not accurately predict the conduction current necessary for the EMP simulation. This is because transport coefficients used in the conduction current calculation will be found based on equilibrium reactions rates which may differ significantly from their non-equilibrium values. We see this deficiency in Los Alamos National Laboratory's EMP code, CHAP-LA (Compton High Altitude Pulse-Los Alamos), when modeling certain EMP scenarios at high altitudes, such as upward EMP, where the ionization rate by secondary electrons is over predicted by the equilibrium model, causing the EMP to short

  8. Non-equilibrium dynamics from RPMD and CMD

    Science.gov (United States)

    Welsch, Ralph; Song, Kai; Shi, Qiang; Althorpe, Stuart C.; Miller, Thomas F.

    2016-11-01

    We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O (t4) and O (t1) , respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O (t5) and O (t2) , respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.

  9. Non-equilibrium dynamics from RPMD and CMD.

    Science.gov (United States)

    Welsch, Ralph; Song, Kai; Shi, Qiang; Althorpe, Stuart C; Miller, Thomas F

    2016-11-28

    We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O(t4) and O(t1), respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O(t5) and O(t2), respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.

  10. High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Torzicky, Teresa; Klein, Thomas

    2012-01-01

    Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera), as it permits a long penetration depth. Complementary to structural images, polarization-sensitive OCT (PS-OCT) images visualize birefringent...... sufficiently large datasets. Here, we demonstrate PS-OCT imaging at 350 kHz A-scan rate using a two-channel PS-OCT system in conjunction with a Fourier domain mode-locked laser. The light source spectrum spans up to 100nm around the water absorption minimum at 1060 nm. By modulating the laser pump current, we...

  11. Bioconversion of red ginseng saponins in the gastro-intestinal tract in vitro model studied by high-performance liquid chromatography-high resolution Fourier transform ion cyclotron resonance mass spectrometry

    NARCIS (Netherlands)

    Kong, H.; Wang, M.; Venema, K.; Maathuis, A.; Heijden, R. van der; Greef, J. van der; Xu, G.; Hankemeier, T.

    2009-01-01

    A high-performance liquid chromatography-high resolution Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FTICR-MS) method was developed to investigate the metabolism of ginsenosides in in vitro models of the gastro-intestinal tract. The metabolites were identified by

  12. Principles of Fourier analysis

    CERN Document Server

    Howell, Kenneth B

    2001-01-01

    Fourier analysis is one of the most useful and widely employed sets of tools for the engineer, the scientist, and the applied mathematician. As such, students and practitioners in these disciplines need a practical and mathematically solid introduction to its principles. They need straightforward verifications of its results and formulas, and they need clear indications of the limitations of those results and formulas.Principles of Fourier Analysis furnishes all this and more. It provides a comprehensive overview of the mathematical theory of Fourier analysis, including the development of Fourier series, "classical" Fourier transforms, generalized Fourier transforms and analysis, and the discrete theory. Much of the author''s development is strikingly different from typical presentations. His approach to defining the classical Fourier transform results in a much cleaner, more coherent theory that leads naturally to a starting point for the generalized theory. He also introduces a new generalized theory based ...

  13. Evaluation of nonequilibrium effects in bundle dispersed-flow film boiling. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.G.; Mullins, C.B.; Yoder, G.L.

    1983-01-01

    The effects of thermodynamic nonequilibrium in dispersed flow film boiling heat transfer are examined. Steady-state and transient rod-bundle data are used to evaluate several empirical heat-transfer models commonly employed to predict post-CHF behavior. The models that account for thermodynamic nonequilibrium perform adequately, while those that ignore nonequilibrium effects incur errors in wall superheat as high as 190/sup 0/K. Nonequilibrium effects can also be treated by explicitly modeling the phenomena. The thermal-hydraulic code COBRA-TF employs this approach. Using bundle data, the models in the code are evaluated. Analysis suggests that the interfacial heat transfer is overpredicted.

  14. Non-equilibrium phase transitions

    CERN Document Server

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  15. Open problems in non-equilibrium physics

    Energy Technology Data Exchange (ETDEWEB)

    Kusnezov, D.

    1997-09-22

    The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.

  16. Trapped ion system for sympathetic cooling and non-equilibrium dynamics

    Science.gov (United States)

    Doret, Charlie; Jubin, Sierra; Stevenson, Sarah

    2017-04-01

    Atomic systems are superbly suited to the study of non-equilibrium dynamics. These systems' exquisite isolation from environmental perturbations leads to long relaxation times that enable exploration of far-from-equilibrium phenomena. We present progress towards trapping chains of multiple co-trapped calcium isotopes geared towards measuring thermal equilibration and sympathetic cooling rates. We also discuss plans for future experiments in non-equilibrium statistical mechanics, including exploration of the quantum-to-classical crossover between ballistic transport and diffusive, Fourier's Law conduction. This work is supported by Cottrell College Science Award from the Research Corporation for Science Advancement and by Williams College.

  17. Fourier transformation for pedestrians

    CERN Document Server

    Butz, Tilman

    2006-01-01

    Meant to serve an "entertaining textbook," this book belongs to a rare genre. It is written for all students and practitioners who deal with Fourier transformation. Fourier series as well as continuous and discrete Fourier transformation are covered, and particular emphasis is placed on window functions. Many illustrations and easy-to-solve exercises make the book especially accessible, and its humorous style will add to the pleasure of learning from it.

  18. Push-Broom-Type Very High-Resolution Satellite Sensor Data Correction Using Combined Wavelet-Fourier and Multiscale Non-Local Means Filtering

    Directory of Open Access Journals (Sweden)

    Wonseok Kang

    2015-09-01

    Full Text Available In very high-resolution (VHR push-broom-type satellite sensor data, both destriping and denoising methods have become chronic problems and attracted major research advances in the remote sensing fields. Since the estimation of the original image from a noisy input is an ill-posed problem, a simple noise removal algorithm cannot preserve the radiometric integrity of satellite data. To solve these problems, we present a novel method to correct VHR data acquired by a push-broom-type sensor by combining wavelet-Fourier and multiscale non-local means (NLM filters. After the wavelet-Fourier filter separates the stripe noise from the mixed noise in the wavelet low- and selected high-frequency sub-bands, random noise is removed using the multiscale NLM filter in both low- and high-frequency sub-bands without loss of image detail. The performance of the proposed method is compared to various existing methods on a set of push-broom-type sensor data acquired by Korean Multi-Purpose Satellite 3 (KOMPSAT-3 with severe stripe and random noise, and the results of the proposed method show significantly improved enhancement results over existing state-of-the-art methods in terms of both qualitative and quantitative assessments.

  19. Push-Broom-Type Very High-Resolution Satellite Sensor Data Correction Using Combined Wavelet-Fourier and Multiscale Non-Local Means Filtering

    Science.gov (United States)

    Kang, Wonseok; Yu, Soohwan; Seo, Doochun; Jeong, Jaeheon; Paik, Joonki

    2015-01-01

    In very high-resolution (VHR) push-broom-type satellite sensor data, both destriping and denoising methods have become chronic problems and attracted major research advances in the remote sensing fields. Since the estimation of the original image from a noisy input is an ill-posed problem, a simple noise removal algorithm cannot preserve the radiometric integrity of satellite data. To solve these problems, we present a novel method to correct VHR data acquired by a push-broom-type sensor by combining wavelet-Fourier and multiscale non-local means (NLM) filters. After the wavelet-Fourier filter separates the stripe noise from the mixed noise in the wavelet low- and selected high-frequency sub-bands, random noise is removed using the multiscale NLM filter in both low- and high-frequency sub-bands without loss of image detail. The performance of the proposed method is compared to various existing methods on a set of push-broom-type sensor data acquired by Korean Multi-Purpose Satellite 3 (KOMPSAT-3) with severe stripe and random noise, and the results of the proposed method show significantly improved enhancement results over existing state-of-the-art methods in terms of both qualitative and quantitative assessments. PMID:26378532

  20. Fractional finite Fourier transform.

    Science.gov (United States)

    Khare, Kedar; George, Nicholas

    2004-07-01

    We show that a fractional version of the finite Fourier transform may be defined by using prolate spheroidal wave functions of order zero. The transform is linear and additive in its index and asymptotically goes over to Namias's definition of the fractional Fourier transform. As a special case of this definition, it is shown that the finite Fourier transform may be inverted by using information over a finite range of frequencies in Fourier space, the inversion being sensitive to noise. Numerical illustrations for both forward (fractional) and inverse finite transforms are provided.

  1. High-Spatial- and High-Temporal-Resolution Dynamic Contrast-enhanced MR Breast Imaging with Sweep Imaging with Fourier Transformation: A Pilot Study

    Science.gov (United States)

    Benson, John C.; Idiyatullin, Djaudat; Snyder, Angela L.; Snyder, Carl J.; Hutter, Diane; Everson, Lenore I.; Eberly, Lynn E.; Nelson, Michael T.; Garwood, Michael

    2015-01-01

    Purpose To report the results of sweep imaging with Fourier transformation (SWIFT) magnetic resonance (MR) imaging for diagnostic breast imaging. Materials and Methods Informed consent was obtained from all participants under one of two institutional review board–approved, HIPAA-compliant protocols. Twelve female patients (age range, 19–54 years; mean age, 41.2 years) and eight normal control subjects (age range, 22–56 years; mean age, 43.2 years) enrolled and completed the study from January 28, 2011, to March 5, 2013. Patients had previous lesions that were Breast Imaging Reporting and Data System 4 and 5 based on mammography and/or ultrasonographic imaging. Contrast-enhanced SWIFT imaging was completed by using a 4-T research MR imaging system. Noncontrast studies were completed in the normal control subjects. One of two sized single-breast SWIFT-compatible transceiver coils was used for nine patients and five controls. Three patients and five control subjects used a SWIFT-compatible dual breast coil. Temporal resolution was 5.9–7.5 seconds. Spatial resolution was 1.00 mm isotropic, with later examinations at 0.67 mm isotropic, and dual breast at 1.00 mm or 0.75 mm isotropic resolution. Results Two nonblinded breast radiologists reported SWIFT image findings of normal breast tissue, benign fibroadenomas (six of six lesions), and malignant lesions (10 of 12 lesions) concordant with other imaging modalities and pathologic reports. Two lesions in two patients were not visualized because of coil field of view. The images yielded by SWIFT showed the presence and extent of known breast lesions. Conclusion The SWIFT technique could become an important addition to breast imaging modalities because it provides high spatial resolution at all points during the dynamic contrast-enhanced examination. © RSNA, 2014 PMID:25247405

  2. Vectorial reconstruction of retinal blood flow in three dimensions measured with high resolution resonant Doppler Fourier domain optical coherence tomography.

    Science.gov (United States)

    Michaely, Roland; Bachmann, Adrian H; Villiger, Martin L; Blatter, Cédric; Lasser, Theo; Leitgeb, Rainer A

    2007-01-01

    Resonant Doppler Fourier domain optical coherence tomography (FDOCT) is a functional imaging tool for extracting tissue flow. The method is based on the effect of interference fringe blurring in spectrometer-based FDOCT, where the path difference between structure and reference changes during camera integration. If the reference path length is changed in resonance with the Doppler frequency of the sample flow, the signals of resting structures will be suppressed, whereas the signals of blood flow are enhanced. This allows for an easy extraction of vascularization structure. Conventional flow velocity analysis extracts only the axial flow component, which strongly depends on the orientation of the vessel with respect to the incident light. We introduce an algorithm to extract the vessel geometry within the 3-D data volume. The algorithm calculates the angular correction according to the local gradients of the vessel orientations. We apply the algorithm on a measured 3-D resonant Doppler dataset. For validation of the reproducibility, we compare two independently obtained 3-D flow maps of the same volunteer and region.

  3. GENFIRE: A Generalized Fourier Iterative Reconstruction Algorithm for High-Resolution 3D Electron and X-ray Imaging

    Science.gov (United States)

    Pryor, Alan; Yang, Yongsoo; Rana, Arjun; Gallagher-Jones, Marcus; Zhou, Jihan; Hung Lo, Yuan; Melinte, Georgian; Rodriguez, Jose A.; Miao, Jianwei

    2017-07-01

    Tomography has made a radical impact on diverse fields ranging from the study of 3D atomic arrangements in matter to the study of human health in medicine. Despite its very diverse applications, the core of tomography remains the same, that is, a mathematical method must be implemented to reconstruct the 3D structure of an object from a number of 2D projections. In many scientific applications, however, the number of projections that can be measured is limited due to geometric constraints, tolerable radiation dose and/or acquisition speed. Thus it becomes an important problem to obtain the best-possible reconstruction from a limited number of projections. Here, we present the mathematical implementation of a tomographic algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE). By iterating between real and reciprocal space, GENFIRE searches for a global solution that is concurrently consistent with the measured data and general physical constraints. The algorithm requires minimal human intervention and also incorporates angular refinement to reduce the tilt angle error. We demonstrate that GENFIRE can produce superior results relative to several other popular tomographic reconstruction techniques by numerical simulations, and by experimentally by reconstructing the 3D structure of a porous material and a frozen-hydrated marine cyanobacterium. Equipped with a graphical user interface, GENFIRE is freely available from our website and is expected to find broad applications across different disciplines.

  4. High-accuracy fourier transform interferometry, without oversampling, with a 1-bit analog-to-digital converter.

    Science.gov (United States)

    Daria, V R; Saloma, C

    2000-01-01

    We demonstrate a new technique for performing accurate Fourier transform interferometry with a 1-bit analog-to-digital (AD) converter that does not require oversampling of the interferogram, unlike in other 1-bit coding schemes that rely on delta-sigma modulation. Sampling aims at locating the intersections {z(i)} of the modulation term s(z) of the interferogram and a reference sinusoid r(z) = A cos(2pif(r)z), where z is the optical path difference. A new autocorrelation-based procedure that includes the accurate recovery of the equally sampled amplitude representation {s(k)} of s(z) from {z(i)} is utilized to calculate the square of the emission spectrum of the light source (sample). The procedure is suitable for interferograms that are corrupted with additive noise. Sinusoid-crossing sampling satisfies the Nyquist sampling criterion, and a z(i) exists within each sampling interval Delta = 1/2f(r), if A >or= |s(z)| for all z, and f(r) >or= f(c), where f(c) is the highest frequency component of s(z). By locating a crossing at an accuracy of 1 part in 2(16), we determine the multimode spectrum of an argon-ion laser with a 1-bit AD converter that performs like a 13-bit amplitude-sampling AD converter.

  5. Non-equilibrium supramolecular polymerization.

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

    2017-09-18

    Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

  6. High-resolution measurements of the K-alpha spectra of low-ionizationm species of iron: A new spectral signature of nonequilibrium ionization conditions in young supernova remnants

    Science.gov (United States)

    Decaux, V.; Beiersdorfer, P.; Osterheld, A.; Chen, M.; Kahn, S. M.

    1995-01-01

    We present the first systematic laboratory measurements of high-resolution K-alpha spectra of intermediate ions of iron, Fe X-XVII. These lines are not produced in collisional equilibrium plasmas because of the relevant charge states cannot exist at the high electron temperatures required for appreciable excitation of the K-alpha transitions. However, they can provide excellent spectral diagnostics for nonequilibrium ionization conditions, such the ionizing plasmas of young supernova remnants. To facilitate the line identifications, we compare our spectra with theoretical atomic calculations performed using multiconfiguration parametric potential and Dirac-Fock atomic codes. Our measurements also allow direct comparison with time-dependent ionization balance calculations for ionizing plasmas, and good agreement is found.

  7. On Fast Fourier Transform

    Indian Academy of Sciences (India)

    His research areas are adaptive signal processing, multirate filtering and wavelets, space-time signal processing for wireless communation. v U Redc!y. Fast Fourier transform (FFT) is an efficient algorithm for computing the discrete Fourier transform. The discovery of the FFT algorithm paved the way for widespread use of.

  8. Generalized Fourier transforms classes

    DEFF Research Database (Denmark)

    Berntsen, Svend; Møller, Steen

    2002-01-01

    The Fourier class of integral transforms with kernels $B(\\omega r)$ has by definition inverse transforms with kernel $B(-\\omega r)$. The space of such transforms is explicitly constructed. A slightly more general class of generalized Fourier transforms are introduced. From the general theory...

  9. Fourier Transform Near Infrared Microspectroscopy, Infrared Chemical Imaging, High-Resolution Nuclear Magnetic Resonance and Fluorescence Microspectroscopy Detection of Single Cancer Cells and Single Viral Particles

    CERN Document Server

    Baianu,I C; Hofmann, N E; Korban, S S; Lozano, P; You, T

    2004-01-01

    Single Cancer Cells from Human tumors are being detected and imaged by Fourier Transform Infrared (FT-IR), Fourier Transform Near Infrared (FT-NIR)Hyperspectral Imaging and Fluorescence Correlation Microspectroscopy. The first FT-NIR chemical, microscopic images of biological systems approaching one micron resolution are here reported. Chemical images obtained by FT-NIR and FT-IR Microspectroscopy are also presented for oil in soybean seeds and somatic embryos under physiological conditions. FT-NIR spectra of oil and proteins were obtained for volumes as small as two cubic microns. Related, HR-NMR analyses of oil contents in somatic embryos as well as 99% accurate calibrations are also presented here with nanoliter precision. Such high-resolution, 400 MHz H-1 NMR analyses allowed the selection of mutagenized embryos with higher oil content (e.g. >~20%) compared to the average levels in non-mutagenized control embryos. Moreover, developmental changes in single soybean seeds and/or somatic embryos may be monito...

  10. Non-equilibrium critical behavior of thin Ising films

    Science.gov (United States)

    Medvedeva, Maria A.; Prudnikov, Pavel V.; Elin, Alexey S.

    2017-10-01

    In this paper we study the non-equilibrium properties of Ising ferromagnetic films using Monte Carlo simulations by short-time dynamic method. We have found thickness dependency of critical exponents z, θ ‧ and β / ν . Ageing effects were observed in non-equilibrium critical behavior. Former was carried out both from high-temperature and low-temperature initial states. A characteristic time of relaxation, which diverges at a transition temperature in the thermodynamic limit, is obtained as a function of the system size and waiting time.

  11. Nonequilibrium fermion production in quantum field theory

    Energy Technology Data Exchange (ETDEWEB)

    Pruschke, Jens

    2010-06-16

    The creation of matter in the early universe or in relativistic heavy-ion collisions is inevitable connected to nonequilibrium physics. One of the key challenges is the explanation of the corresponding thermalization process following nonequilibrium instabilities. The role of fermionic quantum fields in such scenarios is discussed in the literature by using approximations of field theories which neglect important quantum corrections. This thesis goes beyond such approximations. A quantum field theory where scalar bosons interact with Dirac fermions via a Yukawa coupling is analyzed in the 2PI effective action formalism. The chosen approximation allows for a correct description of the dynamics including nonequilibrium instabilities. In particular, fermion-boson loop corrections allow to study the interaction of fermions with large boson fluctuations. The applied initial conditions generate nonequilibrium instabilities like parametric resonance or spinodal instabilities. The equations of motion for correlation functions are solved numerically and major characteristics of the fermion dynamics are described by analytical solutions. New mechanisms for the production of fermions are found. Simulations in the case of spinodal instability show that unstable boson fluctuations induce exponentially growing fermion modes with approximately the same growth rate. If the unstable regime lasts long enough a thermalization of the infrared part of the fermion occupation number occurs on time scales much shorter than the time scale on which bosonic quantum fields thermalize. Fermions acquire an excess of occupation in the ultraviolet regime compared to a Fermi-Dirac statistic characterized by a power-law with exponent two. The fermion production mechanism via parametric resonance is found to be most efficient after the instability ends. Quantum corrections then provide a very efficient particle creation mechanism which is interpreted as an amplification of decay processes. The ratio

  12. Nonequilibrium superconductivity for particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Gray, K.E.

    1987-10-01

    A considerable amount of attention has been devoted to nonequilibrium superconductivity over the last 10 to 15 years. A fairly complete and quantatitive understanding of the experimental and theoretical aspects of the subject has emerged. In this paper aspects of nonequilibrium superconductivity which are relevant to a majority of particle detector applications will be reviewed, and new calculations, more specific to actual detector applications, will be presented. The primary focus is on ionizing particles for which the characteristic energy is greater than typical superconducting energy gap values, ..delta.., of about 1 MeV. Thus microwave and far-infrared detection is excluded, although many of the results and consequences may also apply in those cases. 36 refs., 1 fig.

  13. Nonequilibrium statistical mechanics ensemble method

    CERN Document Server

    Eu, Byung Chan

    1998-01-01

    In this monograph, nonequilibrium statistical mechanics is developed by means of ensemble methods on the basis of the Boltzmann equation, the generic Boltzmann equations for classical and quantum dilute gases, and a generalised Boltzmann equation for dense simple fluids The theories are developed in forms parallel with the equilibrium Gibbs ensemble theory in a way fully consistent with the laws of thermodynamics The generalised hydrodynamics equations are the integral part of the theory and describe the evolution of macroscopic processes in accordance with the laws of thermodynamics of systems far removed from equilibrium Audience This book will be of interest to researchers in the fields of statistical mechanics, condensed matter physics, gas dynamics, fluid dynamics, rheology, irreversible thermodynamics and nonequilibrium phenomena

  14. Thermodynamic Measure for Nonequilibrium Processes

    Directory of Open Access Journals (Sweden)

    Attila Grandpierre

    2007-07-01

    Full Text Available One of the most fundamental laws of Nature is formulated by the Second Law of Thermodynamics. At present, in its usual formulation the central concept is entropy characterized in terms of equilibrium state variables. We point out that because thermodynamic changes arise when systems are out of equilibrium and because entropy is not a natural state variable characterizing non-equilibrium states, a new formulation of the Second Law is required. In this paper, we introduce a new, more general, but still entropic measure that is suitable in non-equilibrium conditions as well. This new entropic measure has given a name extropy. The introduction of extropy allows us to formulate the Second Law in a more suitable and precise form, and it resolves some conceptual difficulties related to the interpretation of entropy. We point out that extropy has a fundamental significance in physics, in biology, and in our scientific worldview.

  15. Non-Equilibrium Quantum Dissipation

    OpenAIRE

    Segal, Dvira; Reichman, David R.; Millis, Andrew J.

    2007-01-01

    Dissipative processes in non-equilibrium many-body systems are fundamentally different than their equilibrium counterparts. Such processes are of great importance for the understanding of relaxation in single molecule devices. As a detailed case study, we investigate here a generic spin-fermion model, where a two-level system couples to two metallic leads with different chemical potentials. We present results for the spin relaxation rate in the nonadiabatic limit for an arbitrary coupling to ...

  16. Computer simulation of nonequilibrium processes

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, D.C.

    1985-07-01

    The underlying concepts of nonequilibrium statistical mechanics, and of irreversible thermodynamics, will be described. The question at hand is then, how are these concepts to be realize in computer simulations of many-particle systems. The answer will be given for dissipative deformation processes in solids, on three hierarchical levels: heterogeneous plastic flow, dislocation dynamics, an molecular dynamics. Aplication to the shock process will be discussed.

  17. HIGH-RESOLUTION FOURIER TRANSFORM INFRARED SPECTRUM OF THE ν2 + ν12 BAND OF ETHYLENE (12C2H4)

    Science.gov (United States)

    Lebron, G. B.; Tan, T. L.

    2013-09-01

    The high-resolution Fourier transform infrared absorption spectrum of the ν2 + ν12 combination band of normal ethylene (12C2H4) in the 3050-3105 cm-1 region was recorded at a resolution of 0.0063 cm-1 and at an ambient temperature of 296 K. Upper state rovibrational analysis was carried out using a standard Watson's Hamiltonian in asymmetric reduction in Ir representation. The band center, rotational constants and centrifugal distortion constants up to quartic terms of the upper ν2 + ν12 = 1 state were determined from the final fit that included 102 infrared transitions. The root-mean-square deviation of the fit was 0.000729 cm-1.

  18. Amyloid Hydrogen Bonding Polymorphism Evaluated by (15)N{(17)O}REAPDOR Solid-State NMR and Ultra-High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    Wei, Juan; Antzutkin, Oleg N; Filippov, Andrei V; Iuga, Dinu; Lam, Pui Yiu; Barrow, Mark P; Dupree, Ray; Brown, Steven P; O'Connor, Peter B

    2016-04-12

    A combined approach, using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and solid-state NMR (Nuclear Magnetic Resonance), shows a high degree of polymorphism exhibited by Aβ species in forming hydrogen-bonded networks. Two Alzheimer's Aβ peptides, Ac-Aβ(16-22)-NH2 and Aβ(11-25), selectively labeled with (17)O and (15)N at specific amino acid residues were investigated. The total amount of peptides labeled with (17)O as measured by FTICR-MS enabled the interpretation of dephasing observed in (15)N{(17)O}REAPDOR solid-state NMR experiments. Specifically, about one-third of the Aβ peptides were found to be involved in the formation of a specific >C═(17)O···H-(15)N hydrogen bond with their neighbor peptide molecules, and we hypothesize that the rest of the molecules undergo ± n off-registry shifts in their hydrogen bonding networks.

  19. High resolution Fourier transform infrared spectroscopy of the ground state, ν3, 2ν3 and ν4 levels of 13CHF3

    Science.gov (United States)

    Bolotova, I. B.; Ulenikov, O. N.; Bekhtereva, E. S.; Albert, S.; Chen, Z.; Hollenstein, H.; Zindel, D.; Quack, M.

    2017-07-01

    We report high resolution (δ ν ˜ ⩽ 0.001cm-1) Fourier Transform Infrared (FTIR) spectra of the trifluoromethane (fluoroform) isotopomer 13CHF3 including results from synchrotron based spectroscopy at the Swiss light source (SLS). The analysis is extended to the pure rotational spectra in the Terahertz (far-infrared) range (15-100 cm-1, δν˜FWHM = 0.0006cm-1), the ν3 fundamental (ν˜0 = 695.292cm-1), the associated ;hot; band 2ν3 -ν3 providing information on the level 2ν3 (ν˜0 = 1389.807cm-1) and the ν4 fundamental (ν˜0 = 1369.013cm-1) coupled to 2ν3 . The results are discussed in relation to the 13C isotope effect on the vibrational quantum dynamics as derived by theory and in relation to fluoroform as a greenhouse gas.

  20. Ultra-high-speed optical serial-to-parallel data conversion by time-domain optical Fourier transformation in a silicon nanowire.

    Science.gov (United States)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Hu, Hao; Ji, Hua; Lillieholm, Mads; Galili, Michael; Clausen, Anders T; Pu, Minhao; Yvind, Kresten; Hvam, Jørn M; Jeppesen, Palle; Oxenløwe, Leif K

    2011-12-12

    We demonstrate conversion from 64 × 10 Gbit/s optical time-division multiplexed (OTDM) data to dense wavelength division multiplexed (DWDM) data with 25 GHz spacing. The conversion is achieved by time-domain optical Fourier transformation (OFT) based on four-wave mixing (FWM) in a 3.6 mm long silicon nanowire. A total of 40 out of 64 tributaries of a 64 × 10 Gbit/s OTDM-DPSK data signal are simultaneously converted with a bit-error rate (BER) performance below the 2 × 10(-3) FEC limit. Using a 50 m long highly nonlinear fiber (HNLF) for higher FWM conversion efficiency, 43 tributaries of a 64 × 10 Gbit/s OTDM-OOK data signal are converted with error-free performance (BER<10(-9)). © 2011 Optical Society of America

  1. A Short Biography of Joseph Fourier and Historical Development of Fourier Series and Fourier Transforms

    Science.gov (United States)

    Debnath, Lokenath

    2012-01-01

    This article deals with a brief biographical sketch of Joseph Fourier, his first celebrated work on analytical theory of heat, his first great discovery of Fourier series and Fourier transforms. Included is a historical development of Fourier series and Fourier transforms with their properties, importance and applications. Special emphasis is made…

  2. Fourier transformation for pedestrians

    CERN Document Server

    Butz, Tilman

    2015-01-01

    This book is an introduction to Fourier Transformation with a focus on signal analysis, based on the first edition. It is well suited for undergraduate students in physics, mathematics, electronic engineering as well as for scientists in research and development. It gives illustrations and recommendations when using existing Fourier programs and thus helps to avoid frustrations. Moreover, it is entertaining and you will learn a lot unconsciously. Fourier series as well as continuous and discrete Fourier transformation are discussed with particular emphasis on window functions. Filter effects of digital data processing are illustrated. Two new chapters are devoted to modern applications. The first deals with data streams and fractional delays and the second with the back-projection of filtered projections in tomography. There are many figures and mostly easy to solve exercises with solutions.

  3. Digital Fourier analysis fundamentals

    CERN Document Server

    Kido, Ken'iti

    2015-01-01

    This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations.  These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...

  4. Generalized fiber Fourier optics.

    Science.gov (United States)

    Cincotti, Gabriella

    2011-06-15

    A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler.

  5. Immersed Boundary Smooth Extension: A high-order method for solving PDE on arbitrary smooth domains using Fourier spectral methods

    OpenAIRE

    Stein, David B.; Guy, Robert D; Thomases, Becca

    2015-01-01

    The Immersed Boundary method is a simple, efficient, and robust numerical scheme for solving PDE in general domains, yet it only achieves first-order spatial accuracy near embedded boundaries. In this paper, we introduce a new high-order numerical method which we call the Immersed Boundary Smooth Extension (IBSE) method. The IBSE method achieves high-order accuracy by smoothly extending the unknown solution of the PDE from a given sm...

  6. The fractional Fourier transform and applications

    Science.gov (United States)

    Bailey, David H.; Swarztrauber, Paul N.

    1991-01-01

    This paper describes the 'fractional Fourier transform', which admits computation by an algorithm that has complexity proportional to the fast Fourier transform algorithm. Whereas the discrete Fourier transform (DFT) is based on integral roots of unity e exp -2(pi)i/n, the fractional Fourier transform is based on fractional roots of unity e exp -2(pi)i(alpha), where alpha is arbitrary. The fractional Fourier transform and the corresponding fast algorithm are useful for such applications as computing DFTs of sequences with prime lengths, computing DFTs of sparse sequences, analyzing sequences with noninteger periodicities, performing high-resolution trigonometric interpolation, detecting lines in noisy images, and detecting signals with linearly drifting frequencies. In many cases, the resulting algorithms are faster by arbitrarily large factors than conventional techniques.

  7. Segmentation of high-resolution InSar data of tropical forest using Fourier parameterised deformable models

    NARCIS (Netherlands)

    Varekamp, C.; Hoekman, D.H.

    2001-01-01

    Currently, tree maps are produced from field measurements that are time consuming and expensive. Application of existing techniques based on aerial photography is often hindered by cloud cover. This has initiated research into the segmentation of high resolution airborne interferometric Synthetic

  8. Laboratory for Engineering Man/Machine Systems (LEMS): System identification, model reduction and deconvolution filtering using Fourier based modulating signals and high order statistics

    Science.gov (United States)

    Pan, Jianqiang

    1992-01-01

    Several important problems in the fields of signal processing and model identification, such as system structure identification, frequency response determination, high order model reduction, high resolution frequency analysis, deconvolution filtering, and etc. Each of these topics involves a wide range of applications and has received considerable attention. Using the Fourier based sinusoidal modulating signals, it is shown that a discrete autoregressive model can be constructed for the least squares identification of continuous systems. Some identification algorithms are presented for both SISO and MIMO systems frequency response determination using only transient data. Also, several new schemes for model reduction were developed. Based upon the complex sinusoidal modulating signals, a parametric least squares algorithm for high resolution frequency estimation is proposed. Numerical examples show that the proposed algorithm gives better performance than the usual. Also, the problem was studied of deconvolution and parameter identification of a general noncausal nonminimum phase ARMA system driven by non-Gaussian stationary random processes. Algorithms are introduced for inverse cumulant estimation, both in the frequency domain via the FFT algorithms and in the domain via the least squares algorithm.

  9. Mid-infrared Fourier-transform spectroscopy with a high-brilliance tunable laser source: investigating sample areas down to 5 μm diameter.

    Science.gov (United States)

    Steinle, T; Neubrech, F; Steinmann, A; Yin, X; Giessen, H

    2015-05-04

    We demonstrate highly sensitive infrared spectroscopy of sample volumes close to the diffraction limit by coupling a femtosecond fiber-feedback optical parametric oscillator (OPO) to a conventional Fourier-transform infrared (FTIR) spectrometer. The high brilliance and long-term stable infrared radiation with 1e(2)-bandwidths up to 125 nm is easily tunable between 1.4 μm and 4.2 μm at 43 MHz repetition rate and thus enables rapid and low-noise infrared spectroscopy. We demonstrate this by measuring typical molecular vibrations in the range of 3 μm. Combined with surface-enhanced infrared spectroscopy, where the confined electromagnetic near-fields of resonantly excited metal nanoparticles are employed to enhance molecular vibrations, we realize the spectroscopic detection of a molecular monolayer of octadecanethiol. In comparison to conventional light sources and synchrotron radiation, our compact table-top OPO system features a significantly improved performance making it highly suitable for rapid analysis of minute amounts of molecular species in life science and medicine laboratories.

  10. On Fourier re-expansions

    OpenAIRE

    Liflyand, E.

    2012-01-01

    We study an extension to Fourier transforms of the old problem on absolute convergence of the re-expansion in the sine (cosine) Fourier series of an absolutely convergent cosine (sine) Fourier series. The results are obtained by revealing certain relations between the Fourier transforms and their Hilbert transforms.

  11. Compact Microwave Fourier Spectrum Analyzer

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

    2009-01-01

    A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

  12. Design principles for nonequilibrium self-assembly.

    Science.gov (United States)

    Nguyen, Michael; Vaikuntanathan, Suriyanarayanan

    2016-12-13

    We consider an important class of self-assembly problems, and using the formalism of stochastic thermodynamics, we derive a set of design principles for growing controlled assemblies far from equilibrium. The design principles constrain the set of configurations that can be obtained under nonequilibrium conditions. Our central result provides intuition for how equilibrium self-assembly landscapes are modified under finite nonequilibrium drive.

  13. Characterization of chemical constituents in Rhodiola Crenulate by high-performance liquid chromatography coupled with Fourier-transform ion cyclotron resonance mass spectrometer (HPLC-FT-ICR MS).

    Science.gov (United States)

    Han, Fei; Li, Yanting; Mao, Xinjuan; Xu, Rui; Yin, Ran

    2016-05-01

    In this work, an approach using high-performance liquid chromatography coupled with diode-array detection and Fourier-transform ion cyclotron resonance mass spectrometer (HPLC-FT-ICR MS) for the identification and profiling of chemical constituents in Rhodiola crenulata was developed for the first time. The chromatographic separation was achieved on an Inertsil ODS-3 column (150 mm × 4.6 mm,3 µm) using a gradient elution program, and the detection was performed on a Bruker Solarix 7.0 T mass spectrometer equipped with electrospray ionization source in both positive and negative modes. Under the optimized conditions, a total of 48 chemical compounds, including 26 alcohols and their glycosides, 12 flavonoids and their glycosides, 5 flavanols and gallic acid derivatives, 4 organic acids and 1 cyanogenic glycoside were identified or tentatively characterized. The results indicated that the developed HPLC-FT-ICR MS method with ultra-high sensitivity and resolution is suitable for identifying and characterizing the chemical constituents in R. crenulata. And it provides a helpful chemical basis for further research on R. crenulata. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Non-dissipative effects in nonequilibrium systems

    CERN Document Server

    Maes, Christian

    2018-01-01

    This book introduces and discusses both the fundamental aspects and the measurability of applications of time-symmetric kinetic quantities, outlining the features that constitute the non-dissipative branch of non-equilibrium physics. These specific features of non-equilibrium dynamics have largely been ignored in standard statistical mechanics texts. This introductory-level book offers novel material that does not take the traditional line of extending standard thermodynamics to the irreversible domain. It shows that although stationary dissipation is essentially equivalent with steady non-equilibrium and ubiquitous in complex phenomena, non-equilibrium is not determined solely by the time-antisymmetric sector of energy-entropy considerations. While this should not be very surprising, this book provides timely, simple reminders of the role of time-symmetric and kinetic aspects in the construction of non-equilibrium statistical mechanics.

  15. Kinetic theory of nonequilibrium ensembles, irreversible thermodynamics, and generalized hydrodynamics

    CERN Document Server

    Eu, Byung Chan

    2016-01-01

    This book presents the fundamentals of irreversible thermodynamics for nonlinear transport processes in gases and liquids, as well as for generalized hydrodynamics extending the classical hydrodynamics of Navier, Stokes, Fourier, and Fick. Together with its companion volume on relativistic theories, it provides a comprehensive picture of the kinetic theory formulated from the viewpoint of nonequilibrium ensembles in both nonrelativistic and, in Vol. 2, relativistic contexts. Theories of macroscopic irreversible processes must strictly conform to the thermodynamic laws at every step and in all approximations that enter their derivation from the mechanical principles. Upholding this as the inviolable tenet, the author develops theories of irreversible transport processes in fluids (gases or liquids) on the basis of irreversible kinetic equations satisfying the H theorem. They apply regardless of whether the processes are near to or far removed from equilibrium, or whether they are linear or nonlinear with respe...

  16. Non-Equilibrium Thermodynamic Chemistry and the Composition of the Atmosphere of Mars

    Science.gov (United States)

    Levine, J. S.; Summers, M. E.

    2003-01-01

    A high priority objective of the Mars Exploration Program is to Determine if life exists today (MEPAG Goal I, Objective A). The measurement of gases of biogenic origin may be an approach to detect the presence of microbial life on the surface or subsurface of Mars. Chemical thermodynamic calculations indicate that on both Earth and Mars, certain gases should exist in extremely low concentrations, if at all. Microbial metabolic activity is an important non-equilibrium chemistry process on Earth, and if microbial life exists on Mars, may be an important nonequilibrium chemistry process on Mars. The non-equilibrium chemistry of the atmosphere of Mars is discussed in this paper.

  17. Fast Fourier orthogonalization

    NARCIS (Netherlands)

    L. Ducas (Léo); T. Prest; S.A. Abramov; E.V. Zima; X-S. Gao

    2016-01-01

    htmlabstractThe classical fast Fourier transform (FFT) allows to compute in quasi-linear time the product of two polynomials, in the {\\em circular convolution ring} R[x]/(x^d−1) --- a task that naively requires quadratic time. Equivalently, it allows to accelerate matrix-vector products when the

  18. Optique de Fourier

    Science.gov (United States)

    Pellat-Finet, Pierre

    L'optique de Fourier doit son nom à l'emploi délibéré de la transformation de Fourier dans la représentation de phénomènes fondés sur la diffraction de la lumière1. Inscrite dans les limites d'une théorie scalaire, elle est, traditionnellement, liée à l'optique cohérente et les sujets développés dans ce livre se rattachent à ce thème. Le domaine et les applications ussuelles de l'optique de Fourier concernent la formation des images, la résolution des instruments d'optique, le traitement du signal optique, l'holographie, le transfert de la cohérence. Nous verrons comment y inclure la théorie des résonateurs optiques et celle des faisseaux gaussiens; celle de la dispersion dans les fibres optiques. L'optique de Fourier fournit ainsi un cadre général à la modélisation d'un grand nombre de phénomènes optiques2.

  19. Mathematical and information-geometrical entropy for phenomenological Fourier and non-Fourier heat conduction

    Science.gov (United States)

    Li, Shu-Nan; Cao, Bing-Yang

    2017-09-01

    The second law of thermodynamics governs the direction of heat transport, which provides the foundational definition of thermodynamic Clausius entropy. The definitions of entropy are further generalized for the phenomenological heat transport models in the frameworks of classical irreversible thermodynamics and extended irreversible thermodynamics (EIT). In this work, entropic functions from mathematics are combined with phenomenological heat conduction models and connected to several information-geometrical conceptions. The long-time behaviors of these mathematical entropies exhibit a wide diversity and physical pictures in phenomenological heat conductions, including the tendency to thermal equilibrium, and exponential decay of nonequilibrium and asymptotics, which build a bridge between the macroscopic and microscopic modelings. In contrast with the EIT entropies, the mathematical entropies expressed in terms of the internal energy function can avoid singularity paired with nonpositive local absolute temperature caused by non-Fourier heat conduction models.

  20. Content adaptive illumination for Fourier ptychography.

    Science.gov (United States)

    Bian, Liheng; Suo, Jinli; Situ, Guohai; Zheng, Guoan; Chen, Feng; Dai, Qionghai

    2014-12-01

    Fourier ptychography (FP) is a recently reported technique, for large field-of-view and high-resolution imaging. Specifically, FP captures a set of low-resolution images, under angularly varying illuminations, and stitches them together in the Fourier domain. One of FP's main disadvantages is its long capturing process, due to the requisite large number of incident illumination angles. In this Letter, utilizing the sparsity of natural images in the Fourier domain, we propose a highly efficient method, termed adaptive Fourier ptychography (AFP), which applies content adaptive illumination for FP, to capture the most informative parts of the scene's spatial spectrum. We validate the effectiveness and efficiency of the reported framework, with both simulated and real experiments. Results show that the proposed AFP could shorten the acquisition time of conventional FP, by around 30%-60%.

  1. Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances.

    Science.gov (United States)

    Banas, Krzysztof; Banas, Agnieszka M; Heussler, Sascha P; Breese, Mark B H

    2018-01-05

    In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Metabolic profile of salidroside in rats using high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Han, Fei; Li, Yan-ting; Mao, Xin-juan; Zhang, Xiao-shu; Guan, Jiao; Song, Ai-hua; Yin, Ran

    2016-03-01

    A high-performance liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FT-ICR MS) method was developed to study the in vivo metabolism of salidroside for the first time. Plasma, urine, bile, and feces samples were collected from male rats after a single intragastric gavage of salidroside at a dose of 50 mg/kg. Besides the parent drug, a total of seven metabolites (three phase I and four phase II metabolites) were detected and tentatively identified by comparing their mass spectrometry profiles with those of salidroside. Results indicated that metabolic pathways of salidroside in male rats included hydroxylation, dehydrogenation, glucuronidation, and sulfate conjugation. Among them, glucuronidation and sulfate conjugation were the major metabolic reactions. And most important, the detection of the sulfation metabolite of p-tyrosol provides a clue for whether the deglycosylation of salidroside occurs in vivo after intragastric gavage. In summary, results obtained in this study may contribute to the better understanding of the safety and mechanism of action of salidroside.

  3. Native Top-Down ESI-MS of 158 kDa Protein Complex by High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Li, Huilin; Wolff, Jeremy J.; Van Orden, Steve L.; Loo, Joseph A.

    2014-01-01

    Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) delivers high resolving power, mass measurement accuracy, and the capabilities for unambiguously sequencing by a top-down MS approach. Here, we report isotopic resolution of a 158 kDa protein complex - tetrameric aldolase with an average absolute deviation of 0.36 ppm and an average resolving power of ~520,000 at m/z 6033 for the 26+ charge state in magnitude mode. Phase correction further improves the resolving power and average absolute deviation by 1.3 fold. Furthermore, native top-down electron capture dissociation (ECD) enables the sequencing of 149 C-terminal amino acid (AA) residues out of 463 total AAs. Combining the data from top-down MS of native and denatured aldolase complexes, a total of 58% of the backbone cleavages efficiency is achieved. The observation of complementary product ion pairs confirms the correctness of the sequence and also the accuracy of the mass fitting of the isotopic distribution of the aldolase tetramer. Top-down MS of the native protein provides complementary sequence information to top-down ECD and CAD MS of the denatured protein. Moreover, native top-down ECD of aldolase tetramer reveals that ECD fragmentation is not limited only to the flexible regions of protein complexes and that regions located on the surface topology are prone to ECD cleavage. PMID:24313806

  4. Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances

    Science.gov (United States)

    Banas, Krzysztof; Banas, Agnieszka M.; Heussler, Sascha P.; Breese, Mark B. H.

    2018-01-01

    In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment.

  5. Chemotaxonomic studies of nine Paris species from China based on ultra-high performance liquid chromatography tandem mass spectrometry and Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Wang, Yuanzhong; Liu, Ehu; Li, Ping

    2017-06-05

    Paris species, which contain steroid saponins, have been used as herb folk medicines in Asia. In the present study, a comprehensive strategy based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and Fourier transform infrared (FT-IR) spectroscopy was firstly proposed to evaluate the chemotaxonomic relationships of nine Paris species sampled from different geographical regions in China. Principle component analysis (PCA) based on FT-IR data revealed chemical similarities in term of the nine species and geographical regions, indicating the accumulation of metabolites affected by the combination of geographical factors and species. The chemotaxonomic relationships of four species supported the morphological taxonomy and implied ancestry from P. polyphylla. After high-efficiency chromatographic separation, ions trap/time-of-flight mass spectrometry (IT-TOFMS) and triple quadrupole mass spectrometry (QQQ-MS) were used to identify unknown metabolites and simultaneously determine six key compounds (polyphyllin I, II, V, VI, VII and gracillin) in Paris species, respectively. The tentative identification of 22 steroid saponins was indicative of a common biosynthetic pathway in Paris species. Phytoecdysones, gracillin and open-chain steroid saponins were considered as key precursors. According to Pearson's correlation analysis, an insignificant correlation was found between diosgenin-type and pennogenin-type saponins belonging to the same biosynthetic pathways in the current stage. Our results could provide a reasonable foundation for chemotaxonomy or further studies of Paris species. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. INTRODUCTION: Nonequilibrium Processes in Plasmas

    Science.gov (United States)

    Petrović, Zoran; Marić, Dragana; Malović, Gordana

    2009-07-01

    This book aims to give a cross section from a wide range of phenomena that, to different degrees, fall under the heading of non-equilibrium phenomenology. The selection is, of course, biased by the interests of the members of the scientific committee and of the FP6 Project 026328 IPB-CNP Reinforcing Experimental Centre for Non-equilibrium Studies with Application in Nano-technologies, Etching of Integrated Circuits and Environmental Research. Some of the papers included here are texts based on selected lectures presented at the Second International Workshop on Non-equilibrium Processes in Plasmas and Environmental Science. However, this volume is not just the proceedings of that conference as it contains a number of papers from authors that did not attend the conference. The goal was to put together a volume that would cover the interests of the project and support further work. It is published in the Institute of Physics journal Journal of Physics: Conference Series to ensure a wide accessibility of the articles. The texts presented here range from in-depth reviews of the current status and past achievements to progress reports of currently developed experimental devices and recently obtained still unpublished results. All papers have been refereed twice, first when speakers were selected based on their reputation and recently published results, and second after the paper was submitted both by the editorial board and individual assigned referees according to the standards of the conference and of the journal. Nevertheless, we still leave the responsibility (and honours) for the contents of the papers to the authors. The papers in this book are review articles that give a summary of the already published work or present the work in progress that will be published in full at a later date (or both). In the introduction to the first volume, in order to show how far reaching, ubiquitous and important non-equilibrium phenomena are, we claimed that ever since the early

  7. Statistical thermodynamics of nonequilibrium processes

    CERN Document Server

    Keizer, Joel

    1987-01-01

    The structure of the theory ofthermodynamics has changed enormously since its inception in the middle of the nineteenth century. Shortly after Thomson and Clausius enunciated their versions of the Second Law, Clausius, Maxwell, and Boltzmann began actively pursuing the molecular basis of thermo­ dynamics, work that culminated in the Boltzmann equation and the theory of transport processes in dilute gases. Much later, Onsager undertook the elucidation of the symmetry oftransport coefficients and, thereby, established himself as the father of the theory of nonequilibrium thermodynamics. Com­ bining the statistical ideas of Gibbs and Langevin with the phenomenological transport equations, Onsager and others went on to develop a consistent statistical theory of irreversible processes. The power of that theory is in its ability to relate measurable quantities, such as transport coefficients and thermodynamic derivatives, to the results of experimental measurements. As powerful as that theory is, it is linear and...

  8. Non-equilibrium phase transitions in a liquid crystal.

    Science.gov (United States)

    Dan, K; Roy, M; Datta, A

    2015-09-07

    The present manuscript describes kinetic behaviour of the glass transition and non-equilibrium features of the "Nematic-Isotropic" (N-I) phase transition of a well known liquid crystalline material N-(4-methoxybenzylidene)-4-butylaniline from the effects of heating rate and initial temperature on the transitions, through differential scanning calorimetry (DSC), Fourier transform infrared and fluorescence spectroscopy. Around the vicinity of the glass transition temperature (Tg), while only a change in the baseline of the ΔCp vs T curve is observed for heating rate (β) > 5 K min(-1), consistent with a glass transition, a clear peak for β ≤ 5 K min(-1) and the rapid reduction in the ΔCp value from the former to the latter rate correspond to an order-disorder transition and a transition from ergodic to non-ergodic behaviour. The ln β vs 1000/T curve for the glass transition shows convex Arrhenius behaviour that can be explained very well by a purely entropic activation barrier [Dan et al., Eur. Phys. Lett. 108, 36007 (2014)]. Fourier transform infrared spectroscopy indicates sudden freezing of the out-of-plane distortion vibrations of the benzene rings around the glass transition temperature and a considerable red shift indicating enhanced coplanarity of the benzene rings and, consequently, enhancement in the molecular ordering compared to room temperature. We further provide a direct experimental evidence of the non-equilibrium nature of the N-I transition through the dependence of this transition temperature (TNI) and associated enthalpy change (ΔH) on the initial temperature (at fixed β-values) for the DSC scans. A plausible qualitative explanation based on Mesquita's extension of Landau-deGennes theory [O. N. de Mesquita, Braz. J. Phys. 28, 257 (1998)] has been put forward. The change in the molecular ordering from nematic to isotropic phase has been investigated through fluorescence anisotropy measurements where the order parameter, quantified by the

  9. High-performance metabolic profiling with dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) for study of the exposome.

    Science.gov (United States)

    Soltow, Quinlyn A; Strobel, Frederick H; Mansfield, Keith G; Wachtman, Lynn; Park, Youngja; Jones, Dean P

    2013-03-01

    Studies of gene-environment (G × E) interactions require effective characterization of all environmental exposures from conception to death, termed the exposome. The exposome includes environmental exposures that impact health. Improved metabolic profiling methods are needed to characterize these exposures for use in personalized medicine. In the present study, we compared the analytic capability of dual chromatography-Fourier-transform mass spectrometry (DC-FTMS) to previously used liquid chromatography-FTMS (LC-FTMS) analysis for high-throughput, top-down metabolic profiling. For DC-FTMS, we combined data from sequential LC-FTMS analyses using reverse phase (C18) chromatography and anion exchange (AE) chromatography. Each analysis was performed with electrospray ionization in the positive ion mode and detection from m/z 85 to 850. Run time for each column was 10 min with gradient elution; 10 µl extracts of plasma from humans and common marmosets were used for analysis. In comparison to analysis with the AE column alone, addition of the second LC-FTMS analysis with the C18 column increased m/z feature detection by 23-36%, yielding a total number of features up to 7,000 for individual samples. Approximately 50% of the m/z matched to known chemicals in metabolomic databases, and 23% of the m/z were common to analyses on both columns. Database matches included insecticides, herbicides, flame retardants, and plasticizers. Modularity clustering algorithms applied to MS-data showed the ability to detection clusters and ion interactions. DC-FTMS thus provides improved capability for high-performance metabolic profiling of the exposome and development of personalized medicine.

  10. High resolution synchrotron radiation Fourier transform infrared spectrum of the COH-bending mode in methanol-D1 (CH2DOH)

    Science.gov (United States)

    Mukhopadhyay, Indra; Billinghurst, B. E.

    2017-09-01

    In this work the high resolution synchrotron radiation Fourier transform spectrum in the range 1180-1300 cm-1 corresponding to the COH-bending vibrational mode has been recorded and analyzed. The spectrum shows a structure analogous to a parallel band. Since the COH bending motion is one of the main contributors to the asymmetry in the torsional hindering potential barrier, the torsional barrier height in the excited state is expected to be quite different from that of the ground state. This makes the spectrum to spread over a wide region. Although the spectrum corresponding to the P- and R-branch looks very complicated, the Q-branches are well resolved and can be identified without much difficulty. It was possible to assign the spectra for K = 0 to 10 for the trans- (e0) species. The interesting feature of the spectra is the absence of the lines for two other lower lying gauche symmetry species e1 and o1. The spectra due to any perpendicular transitions were absent as well. However some weak c-type transitions from gauche states (o1 and e1) in the ground state to the trans-species (e0) in the COD bending mode for low K-values ΔK = 0 have been seen to be present in the spectra. These along with similar transitions for the OCD vibrational band are under investigation and the results will be communicated elsewhere. In the present work, analysis of the spectrum has been carried out to obtain precise term values and molecular parameters in the excited COH-bending state for the trans-species. The results will be shown valuable to assign similar spectra for the methanol-D2. This work represents the first reported high resolution study of this illusive vibrational mode in methanol-D1.

  11. Classical Fourier analysis

    CERN Document Server

    Grafakos, Loukas

    2014-01-01

    The main goal of this text is to present the theoretical foundation of the field of Fourier analysis on Euclidean spaces. It covers classical topics such as interpolation, Fourier series, the Fourier transform, maximal functions, singular integrals, and Littlewood–Paley theory. The primary readership is intended to be graduate students in mathematics with the prerequisite including satisfactory completion of courses in real and complex variables. The coverage of topics and exposition style are designed to leave no gaps in understanding and stimulate further study. This third edition includes new Sections 3.5, 4.4, 4.5 as well as a new chapter on “Weighted Inequalities,” which has been moved from GTM 250, 2nd Edition. Appendices I and B.9 are also new to this edition.  Countless corrections and improvements have been made to the material from the second edition. Additions and improvements include: more examples and applications, new and more relevant hints for the existing exercises, new exercises, and...

  12. Simplified fractional Fourier transforms.

    Science.gov (United States)

    Pei, S C; Ding, J J

    2000-12-01

    The fractional Fourier transform (FRFT) has been used for many years, and it is useful in many applications. Most applications of the FRFT are based on the design of fractional filters (such as removal of chirp noise and the fractional Hilbert transform) or on fractional correlation (such as scaled space-variant pattern recognition). In this study we introduce several types of simplified fractional Fourier transform (SFRFT). Such transforms are all special cases of a linear canonical transform (an affine Fourier transform or an ABCD transform). They have the same capabilities as the original FRFT for design of fractional filters or for fractional correlation. But they are simpler than the original FRFT in terms of digital computation, optical implementation, implementation of gradient-index media, and implementation of radar systems. Our goal is to search for the simplest transform that has the same capabilities as the original FRFT. Thus we discuss not only the formulas and properties of the SFRFT's but also their implementation. Although these SFRFT's usually have no additivity properties, they are useful for the practical applications. They have great potential for replacing the original FRFT's in many applications.

  13. Fourier techniques and applications

    CERN Document Server

    1985-01-01

    The first systematic methods of Fourier analysis date from the early eighteenth century with the work of Joseph Fourier on the problem of the flow of heat. (A brief history is contained in the first paper.) Given the initial tempera­ ture at all points of a region, the problem was to determine the changes in the temperature distribution over time. Understanding and predicting these changes was important in such areas as the handling of metals and the determination of geological and atmospheric temperatures. Briefly, Fourier noticed that the solution of the heat diffusion problem was simple if the initial temperature dis­ tribution was sinusoidal. He then asserted that any distri­ bution can be decomposed into a sum of sinusoids, these being the harmonics of the original function. This meant that the general solution could now be obtained by summing the solu­ tions of the component sinusoidal problems. This remarkable ability of the series of sinusoids to describe all "reasonable" functions, the sine qua n...

  14. Fourier-transform optical microsystems

    Science.gov (United States)

    Collins, S. D.; Smith, R. L.; Gonzalez, C.; Stewart, K. P.; Hagopian, J. G.; Sirota, J. M.

    1999-01-01

    The design, fabrication, and initial characterization of a miniature single-pass Fourier-transform spectrometer (FTS) that has an optical bench that measures 1 cm x 5 cm x 10 cm is presented. The FTS is predicated on the classic Michelson interferometer design with a moving mirror. Precision translation of the mirror is accomplished by microfabrication of dovetailed bearing surfaces along single-crystal planes in silicon. Although it is miniaturized, the FTS maintains a relatively high spectral resolution, 0.1 cm-1, with adequate optical throughput.

  15. Fourier transforms principles and applications

    CERN Document Server

    Hansen, Eric W

    2014-01-01

    Fourier Transforms: Principles and Applications explains transform methods and their applications to electrical systems from circuits, antennas, and signal processors-ably guiding readers from vector space concepts through the Discrete Fourier Transform (DFT), Fourier series, and Fourier transform to other related transform methods.  Featuring chapter end summaries of key results, over two hundred examples and four hundred homework problems, and a Solutions Manual this book is perfect for graduate students in signal processing and communications as well as practicing engineers.

  16. The application Of Fourier Prediction Models To Schedule Paddy Growing Season With High Resolution For Upgrading Farm Capacity Building (Case Study in Indramayu Regency)

    Science.gov (United States)

    Martuani Siregar, Plato

    2016-08-01

    Indonesian government still has obstacles in the production of annual paddy harvest and planting which causes a decrease 20 percent drop in National production. The failure of one of them caused by weather patterns and climate change that makes farmers difficult to plan future activities with good crop calender. That is because the coming of the rainy season at this moment cannot be predicted precisely. To that end, the role of technology in model and estimate the precise rainfall (high resolution) becomes very important. The developing Fourier prediction models to become agriculture information system was user friendly for instructor/extension officers and farmers who can overcome this problem. The agriculture information models are developed to determine the time of crop calendar weighted maps with rice terraces whom government services, scout and farmers at Indramayu regency easily wears it. The sum of sinus models is used alternatively to predict deciles futures and monthly rainfalls for one year ahead produce a 0.97 correlation with the observed data in Indramayu region. The residue of the sum of sinus models became anomalous rainfall for instan ENSO can cause forward and late in rainfall season. Basically by using a method of curve fitting Sum of Sine results turned out to be related to the monsoon event and climate classification that indicate to distribute annual. While residue model shows cycles of 28.89,61.79 and 80.9 months. These frequencies are related to ENSO event. The Schmidt & Ferguson climate classification of rainfalls and wind monthly conclude Indramayu Regency dominate by type of wet and dry monthly. Map early in the season prediction and map early the planting of rice that have been tested since the start built 2008 is currently being updated with a system software, so that will make it easier for farmers and extension officers as well as related service to apply it on crop calendar.

  17. Referesher Course on Contemporary Non-Equilibrium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Referesher Course on Contemporary Non-Equilibrium Thermodynamics and Statistical Mechanics. Information and Announcements Volume 15 Issue 7 July 2010 pp 678-678 ...

  18. Ultra-high-speed optical serial-to-parallel data conversion by time-domain optical Fourier transformation in a silicon nanowire

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Hu, Hao

    2011-01-01

    We demonstrate conversion from 64 × 10 Gbit/s optical timedivision multiplexed (OTDM) data to dense wavelength division multiplexed (DWDM) data with 25 GHz spacing. The conversion is achieved by time-domain optical Fourier transformation (OFT) based on four-wave mixing (FWM) in a 3.6 mm long...

  19. Quantum thermodynamics: a nonequilibrium Green's function approach.

    Science.gov (United States)

    Esposito, Massimiliano; Ochoa, Maicol A; Galperin, Michael

    2015-02-27

    We establish the foundations of a nonequilibrium theory of quantum thermodynamics for noninteracting open quantum systems strongly coupled to their reservoirs within the framework of the nonequilibrium Green's functions. The energy of the system and its coupling to the reservoirs are controlled by a slow external time-dependent force treated to first order beyond the quasistatic limit. We derive the four basic laws of thermodynamics and characterize reversible transformations. Stochastic thermodynamics is recovered in the weak coupling limit.

  20. Non-equilibrium dog-flea model

    Science.gov (United States)

    Ackerson, Bruce J.

    2017-11-01

    We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.

  1. Aerospace Applications of Non-Equilibrium Plasma

    Science.gov (United States)

    Blankson, Isaiah M.

    2016-01-01

    Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).

  2. The nonequilibrium Ehrenfest gas: a chaotic model with flat obstacles?

    Science.gov (United States)

    Bianca, Carlo; Rondoni, Lamberto

    2009-03-01

    It is known that the nonequilibrium version of the Lorentz gas (a billiard with dispersing obstacles [Ya. G. Sinai, Russ. Math. Surv. 25, 137 (1970)], electric field, and Gaussian thermostat) is hyperbolic if the field is small [N. I. Chernov, Ann. Henri Poincare 2, 197 (2001)]. Differently the hyperbolicity of the nonequilibrium Ehrenfest gas constitutes an open problem since its obstacles are rhombi and the techniques so far developed rely on the dispersing nature of the obstacles [M. P. Wojtkowski, J. Math. Pures Appl. 79, 953 (2000)]. We have developed analytical and numerical investigations that support the idea that this model of transport of matter has both chaotic (positive Lyapunov exponent) and nonchaotic steady states with a quite peculiar sensitive dependence on the field and on the geometry, not observed before. The associated transport behavior is correspondingly highly irregular, with features whose understanding is of both theoretical and technological interests.

  3. 14th International Conference on Nonequilibrium Carrier Dynamics in Semiconductors

    CERN Document Server

    Saraniti, M; Nonequilibrium Carrier Dynamics in Semiconductors

    2006-01-01

    International experts gather every two years at this established conference to discuss recent developments in theory and experiment in non-equilibrium transport phenomena. These developments have been the driving force behind the spectacular advances in semiconductor physics and devices over the last few decades. Originally known as "Hot Carriers in Semiconductors," the 14th conference in the series covered a wide spectrum of traditional topics dealing with non-equilibrium phenomena, ranging from quantum transport to optical phenomena in mesoscopic and nano-scale structures. Particular attention was given this time to emerging areas of this rapidly evolving field, with many sessions covering terahertz devices, high field transport in nitride semiconductors, spintronics, molecular electronics, and bioelectronics applications.

  4. Maximum work extraction and implementation costs for nonequilibrium Maxwell's demons

    Science.gov (United States)

    Sandberg, Henrik; Delvenne, Jean-Charles; Newton, Nigel J.; Mitter, Sanjoy K.

    2014-10-01

    We determine the maximum amount of work extractable in finite time by a demon performing continuous measurements on a quadratic Hamiltonian system subjected to thermal fluctuations, in terms of the information extracted from the system. The maximum work demon is found to apply a high-gain continuous feedback involving a Kalman-Bucy estimate of the system state and operates in nonequilibrium. A simple and concrete electrical implementation of the feedback protocol is proposed, which allows for analytic expressions of the flows of energy, entropy, and information inside the demon. This let us show that any implementation of the demon must necessarily include an external power source, which we prove both from classical thermodynamics arguments and from a version of Landauer's memory erasure argument extended to nonequilibrium linear systems.

  5. Imaging Nonequilibrium Atomic Vibrations with X-ray Diffuse Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Trigo, M.; Chen, J.; Vishwanath, V.H.; /SLAC; Sheu, Y.M.; /Michigan U.; Graber, T.; Henning, R.; /U. Chicago; Reis, D; /SLAC /Stanford U., Appl. Phys. Dept.

    2011-03-03

    We use picosecond x-ray diffuse scattering to image the nonequilibrium vibrations of the lattice following ultrafast laser excitation. We present images of nonequilibrium phonons in InP and InSb throughout the Brillouin-zone which remain out of equilibrium up to nanoseconds. The results are analyzed using a Born model that helps identify the phonon branches contributing to the observed features in the time-resolved diffuse scattering. In InP this analysis shows a delayed increase in the transverse acoustic (TA) phonon population along high-symmetry directions accompanied by a decrease in the longitudinal acoustic (LA) phonons. In InSb the increase in TA phonon population is less directional.

  6. Fourier transforms in spectroscopy

    CERN Document Server

    Kauppinen, Jyrki

    2000-01-01

    This modern approach to the subject is clearly and logically structured, and gives readers an understanding of the essence of Fourier transforms and their applications. All important aspects are included with respect to their use with optical spectroscopic data. Based on popular lectures, the authors provide the mathematical fundamentals and numerical applications which are essential in practical use. The main part of the book is dedicated to applications of FT in signal processing and spectroscopy, with IR and NIR, NMR and mass spectrometry dealt with both from a theoretical and practical poi

  7. Fourier Domain Sensing

    Science.gov (United States)

    Feldkhun, Daniel (Inventor); Wagner, Kelvin H. (Inventor)

    2013-01-01

    Methods and systems are disclosed of sensing an object. A first radiation is spatially modulated to generate a structured second radiation. The object is illuminated with the structured second radiation such that the object produces a third radiation in response. Apart from any spatially dependent delay, a time variation of the third radiation is spatially independent. With a single-element detector, a portion of the third radiation is detected from locations on the object simultaneously. At least one characteristic of a sinusoidal spatial Fourier-transform component of the object is estimated from a time-varying signal from the detected portion of the third radiation.

  8. Nonequilibrium emergent phenomena in organic molecular solids

    Energy Technology Data Exchange (ETDEWEB)

    Mitrano, Matteo

    2015-07-15

    The manipulation of matter with ultrashort laser pulses is a relevant research field from both a fundamental and an applied perspective, owing to the efficient coupling to the electronic degrees of freedom on femtosecond timescales and the ability to induce transient phases that cannot be realized in equilibrium scenarios. Strongly correlated materials are a natural environment for the observation of such novel and emergent out-of-equilibrium physics because small modifications to the electron-electron interactions can induce transitions between remarkably different macroscopic phases. One of the most effective means of modifying the effective electron-electron interactions is to perturb the crystal structure through pressure, strain or even light. However, it remains largely unexplored how perturbing the structural degrees of freedom affects the electron dynamics of the transiently driven states and how the interplay of correlations and electron-lattice interactions determine the intrinsic timescales of these nonequilibrium states. This thesis investigates how to control the light-induced nonequilibrium electronic properties in strongly correlated organics, that are highly tunable with moderate variations of external parameters, by perturbing their structural degrees of freedom, either via static pressures or vibrational excitation. We study the role of correlations in determining the relaxation rate of holes (holons) and double occupancies (doublons) in a solid state Mott insulator, the ET-F{sub 2}TCNQ, driven across a transient insulator-to-metal transition. By mapping holon-doublon lifetimes onto the ground-state electronic interactions, we found that the decay rate of the photoinjected quasiparticles depends on the degree of correlation between carriers and is affected by the presence of a competition between local recombination and delocalization of holon-doublon pairs. By optically controlling the effective correlations in organic molecular crystals through

  9. Modeling High Altitude EMP using a Non-Equilibrium Electron Swarm Model to Monitor Conduction Electron Evolution (LA-UR-15-26151)

    Science.gov (United States)

    Pusateri, E. N.; Morris, H. E.; Nelson, E.; Ji, W.

    2015-12-01

    Electromagnetic pulse (EMP) events in the atmosphere are important physical phenomena that occur through both man-made and natural processes, such as lightning, and can be disruptive to surrounding electrical systems. Due to the disruptive nature of EMP, it is important to accurately predict EMP evolution and propagation with computational models. In EMP, low-energy conduction electrons are produced from Compton electron or photoelectron ionizations with air. These conduction electrons continue to interact with the surrounding air and alter the EMP waveform. Many EMP simulation codes use an equilibrium ohmic model for computing the conduction current. The equilibrium model works well when the equilibration time is short compared to the rise time or duration of the EMP. However, at high altitude, the conduction electron equilibration time can be comparable to or longer than the rise time or duration of the EMP. This matters, for example, when calculating the EMP propagating upward toward a satellite. In these scenarios, the equilibrium ionization rate becomes very large for even a modest electric field. The ohmic model produces an unphysically large number of conduction electrons that prematurely and abruptly short the EMP in the simulation code. An electron swarm model, which simulates the time evolution of conduction electrons, can be used to overcome the limitations exhibited by the equilibrium ohmic model. We have developed and validated an electron swarm model in an environment characterized by electric field and pressure previously in Pusateri et al. (2015). This swarm model has been integrated into CHAP-LA, a state-of-the-art EMP code developed by researchers at Los Alamos National Laboratory, which previously calculated conduction current using an ohmic model. We demonstrate the EMP damping behavior caused by the ohmic model at high altitudes and show improvements on high altitude EMP modeling obtained by employing the swarm model.

  10. Ultrafast Fourier-transform parallel processor

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, W.L.

    1980-04-01

    A new, flexible, parallel-processing architecture is developed for a high-speed, high-precision Fourier transform processor. The processor is intended for use in 2-D signal processing including spatial filtering, matched filtering and image reconstruction from projections.

  11. Fourier Transform Spectrometer System

    Science.gov (United States)

    Campbell, Joel F. (Inventor)

    2014-01-01

    A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

  12. Rainbow Fourier Transform

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.

    2012-01-01

    We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135deg and 165deg exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).

  13. Multi-year comparisons of ground-based and space-borne Fourier transform spectrometers in the high Arctic between 2006 and 2013

    Directory of Open Access Journals (Sweden)

    D. Griffin

    2017-09-01

    Full Text Available This paper presents 8 years (2006–2013 of measurements obtained from Fourier transform spectrometers (FTSs in the high Arctic at the Polar Environment Atmospheric Research Laboratory (PEARL; 80.05° N, 86.42° W. These measurements were taken as part of the Canadian Arctic ACE (Atmospheric Chemistry Experiment validation campaigns that have been carried out since 2004 during the polar sunrise period (from mid-February to mid-April. Each spring, two ground-based FTSs were used to measure total and partial columns of HF, O3, and trace gases that impact O3 depletion, namely, HCl and HNO3. Additionally, some tropospheric greenhouse gases and pollutant species were measured, namely CH4, N2O, CO, and C2H6. During the same time period, the satellite-based ACE-FTS made measurements near Eureka and provided profiles of the same trace gases. Comparisons have been carried out between the measurements from the Portable Atmospheric Research Interferometric Spectrometer for the InfraRed (PARIS-IR and the co-located high-resolution Bruker 125HR FTS, as well as with the latest version of the ACE-FTS retrievals (v3.5. The total column comparison between the two co-located ground-based FTSs, PARIS-IR and Bruker 125HR, found very good agreement for most of these species (except HF, with differences well below the estimated uncertainties ( ≤ 6  % and with high correlations (R ≥ 0. 8. Partial columns have been used for the ground-based to space-borne comparison, with coincident measurements selected based on time, distance, and scaled potential vorticity (sPV. The comparisons of the ground-based measurements with ACE-FTS show good agreement in the partial columns for most species within 6  % (except for C2H6 and PARIS-IR HF, which is consistent with the total retrieval uncertainty of the ground-based instruments. The correlation coefficients (R of the partial column comparisons for all eight species range from approximately 0.75 to 0

  14. Non-Equilibrium Thermodynamics of Transcriptional Bursts

    Science.gov (United States)

    Hernández-Lemus, Enrique

    Gene transcription or Gene Expression (GE) is the process which transforms the information encoded in DNA into a functional RNA message. It is known that GE can occur in bursts or pulses. Transcription is irregular, with strong periods of activity, interspersed by long periods of inactivity. If we consider the average behavior over millions of cells, this process appears to be continuous. But at the individual cell level, there is considerable variability, and for most genes, very little activity at any one time. Some have claimed that GE bursting can account for the high variability in gene expression occurring between cells in isogenic populations. This variability has a big impact on cell behavior and thus on phenotypic conditions and disease. In view of these facts, the development of a thermodynamic framework to study gene expression and transcriptional regulation to integrate the vast amount of molecular biophysical GE data is appealing. Application of such thermodynamic formalism is useful to observe various dissipative phenomena in GE regulatory dynamics. In this chapter we will examine at some detail the complex phenomena of transcriptional bursts (specially of a certain class of anomalous bursts) in the context of a non-equilibrium thermodynamics formalism and will make some initial comments on the relevance of some irreversible processes that may be connected to anomalous transcriptional bursts.

  15. Local entropy of a nonequilibrium fermion system

    Science.gov (United States)

    Stafford, Charles A.; Shastry, Abhay

    2017-03-01

    The local entropy of a nonequilibrium system of independent fermions is investigated and analyzed in the context of the laws of thermodynamics. It is shown that the local temperature and chemical potential can only be expressed in terms of derivatives of the local entropy for linear deviations from local equilibrium. The first law of thermodynamics is shown to lead to an inequality, not equality, for the change in the local entropy as the nonequilibrium state of the system is changed. The maximum entropy principle (second law of thermodynamics) is proven: a nonequilibrium distribution has a local entropy less than or equal to a local equilibrium distribution satisfying the same constraints. It is shown that the local entropy of the system tends to zero when the local temperature tends to zero, consistent with the third law of thermodynamics.

  16. Non-Equilibrium Thermodynamics in Multiphase Flows

    CERN Document Server

    Mauri, Roberto

    2013-01-01

    Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...

  17. Nonequilibrium thermodynamics of restricted Boltzmann machines

    Science.gov (United States)

    Salazar, Domingos S. P.

    2017-08-01

    In this work, we analyze the nonequilibrium thermodynamics of a class of neural networks known as restricted Boltzmann machines (RBMs) in the context of unsupervised learning. We show how the network is described as a discrete Markov process and how the detailed balance condition and the Maxwell-Boltzmann equilibrium distribution are sufficient conditions for a complete thermodynamics description, including nonequilibrium fluctuation theorems. Numerical simulations in a fully trained RBM are performed and the heat exchange fluctuation theorem is verified with excellent agreement to the theory. We observe how the contrastive divergence functional, mostly used in unsupervised learning of RBMs, is closely related to nonequilibrium thermodynamic quantities. We also use the framework to interpret the estimation of the partition function of RBMs with the annealed importance sampling method from a thermodynamics standpoint. Finally, we argue that unsupervised learning of RBMs is equivalent to a work protocol in a system driven by the laws of thermodynamics in the absence of labeled data.

  18. Nonequilibrium statistical physics a modern perspective

    CERN Document Server

    Livi, Roberto

    2017-01-01

    Statistical mechanics has been proven to be successful at describing physical systems at thermodynamic equilibrium. Since most natural phenomena occur in nonequilibrium conditions, the present challenge is to find suitable physical approaches for such conditions: this book provides a pedagogical pathway that explores various perspectives. The use of clear language, and explanatory figures and diagrams to describe models, simulations and experimental findings makes the book a valuable resource for undergraduate and graduate students, and also for lecturers organizing teaching at varying levels of experience in the field. Written in three parts, it covers basic and traditional concepts of nonequilibrium physics, modern aspects concerning nonequilibrium phase transitions, and application-orientated topics from a modern perspective. A broad range of topics is covered, including Langevin equations, Levy processes, directed percolation, kinetic roughening and pattern formation.

  19. How active forces influence nonequilibrium glass transitions

    Science.gov (United States)

    Berthier, Ludovic; Flenner, Elijah; Szamel, Grzegorz

    2017-12-01

    Dense assemblies of self-propelled particles undergo a nonequilibrium form of glassy dynamics. Physical intuition suggests that increasing departure from equilibrium due to active forces fluidifies a glassy system. We falsify this belief by devising a model of self-propelled particles where increasing departure from equilibrium can both enhance or depress glassy dynamics, depending on the chosen state point. We analyze a number of static and dynamic observables and suggest that the location of the nonequilibrium glass transition is primarily controlled by the evolution of two-point static density correlations due to active forces. The dependence of the density correlations on the active forces varies non-trivially with the details of the system, and is difficult to predict theoretically. Our results emphasize the need to develop an accurate liquid state theory for nonequilibrium systems.

  20. Nonequilibrium Quantum Simulation in Circuit QED

    Science.gov (United States)

    Raftery, James John

    Superconducting circuits have become a leading architecture for quantum computing and quantum simulation. In particular, the circuit QED framework leverages high coherence qubits and microwave resonators to construct systems realizing quantum optics models with exquisite precision. For example, the Jaynes-Cummings model has been the focus of significant theoretical interest as a means of generating photon-photon interactions. Lattices of such strongly correlated photons are an exciting new test bed for exploring non-equilibrium condensed matter physics such as dissipative phase transitions of light. This thesis covers a series of experiments which establish circuit QED as a powerful tool for exploring condensed matter physics with photons. The first experiment explores the use of ultra high speed arbitrary waveform generators for the direct digital synthesis of complex microwave waveforms. This new technique dramatically simplifies the classical control chain for quantum experiments and enables high bandwidth driving schemes expected to be essential for generating interesting steady-states and dynamical behavior. The last two experiments explore the rich physics of interacting photons, with an emphasis on small systems where a high degree of control is possible. The first experiment realizes a two-site system called the Jaynes-Cummings dimer, which undergoes a self-trapping transition where the strong photon-photon interactions block photon hopping between sites. The observation of this dynamical phase transition and the related dissipation-induced transition are key results of this thesis. The final experiment augments the Jaynes-Cummings dimer by redesigning the circuit to include in-situ control over photon hopping between sites using a tunable coupler. This enables the study of the dimer's localization transition in the steady-state regime.

  1. Plasma wave instabilities in nonequilibrium graphene

    DEFF Research Database (Denmark)

    Aryal, Chinta M.; Hu, Ben Yu-Kuang; Jauho, Antti-Pekka

    2016-01-01

    We study two-stream instabilities in a nonequilibrium system in which a stream of electrons is injected into doped graphene. As with equivalent nonequilibrium parabolic band systems, we find that the graphene systems can support unstable charge-density waves whose amplitudes grow with time. We...... determine the range of wave vectors q that are unstable, and their growth rates. We find no instability for waves with wave vectors parallel or perpendicular to the direction of the injected carriers. We find that, within the small-wave-vector approximation, the angle between q and the direction...

  2. Non-equilibrium modelling of distillation

    NARCIS (Netherlands)

    Wesselingh, JA; Darton, R

    1997-01-01

    There are nasty conceptual problems in the classical way of describing distillation columns via equilibrium stages, and efficiencies or HETP's. We can nowadays avoid these problems by simulating the behaviour of a complete column in one go using a non-equilibrium model. Such a model has phase

  3. Transmission eigenchannels from nonequilibrium Green's functions

    DEFF Research Database (Denmark)

    Paulsson, Magnus; Brandbyge, Mads

    2007-01-01

    The concept of transmission eigenchannels is described in a tight-binding nonequilibrium Green's function (NEGF) framework. A simple procedure for calculating the eigenchannels is derived using only the properties of the device subspace and quantities normally available in a NEGF calculation...

  4. Non-equilibrium thermodynamics and physical kinetics

    CERN Document Server

    Bikkin, Halid

    2014-01-01

    This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.

  5. Evolution and non-equilibrium physics

    DEFF Research Database (Denmark)

    Becker, Nikolaj; Sibani, Paolo

    2014-01-01

    We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...

  6. Nonequilibrium modeling of three-phase distillation

    NARCIS (Netherlands)

    Higler, A.P.; Chande, R.; Taylor, R.; Baur, R.; Krishna, R.

    2004-01-01

    A nonequilibrium (NEQ) model for a complete three-phase distillation in tray columns is described. The model consists of a set of mass and energy balances for each of the three possible phases present. Mass and heat transfer between these phases is modeled using the Maxwell–Stefan equations.

  7. Modeling interfacial dynamics using nonequilibrium thermodynamics frameworks

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2013-01-01

    In recent years several nonequilibrium thermodynamic frameworks have been developed capable of describing the dynamics of multiphase systems with complex microstructured interfaces. In this paper we present an overview of these frameworks. We will discuss interfacial dynamics in the context of the

  8. Conserving GW scheme for nonequilibrium quantum transport in molecular contacts

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Rubio, Angel

    2008-01-01

    demonstrate that the one-shot G(0)W(0) approximation can produce severe errors, in particular, at high bias. Finally, we consider a benzene molecule between featureless leads. It is found that the molecule's highest occupied molecular orbital-lowest unoccupied molecular orbital gap as calculated in GW......We give a detailed presentation of our recent scheme to include correlation effects in molecular transport calculations using the nonequilibrium Keldysh formalism. The scheme is general and can be used with any quasiparticle self-energy, but for practical reasons, we mainly specialize to the so...

  9. Nonequilibrium flows with smooth particle applied mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Kum, Oyeon [Univ. of California, Davis, CA (United States)

    1995-07-01

    Smooth particle methods are relatively new methods for simulating solid and fluid flows through they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separately controlled. The gradient algorithm, based on differentiating the smooth particle expression for (uρ) and (Tρ), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier`s heat-flow law and Newton`s viscous force law are used. Smooth particle methods show an interesting parallel linking to them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, B spline, Lucy, and Cusp functions. The accuracy and applicability of the methods were estimated by comparing a set of smooth particle Rayleigh-Benard problems, all in the laminar regime, to corresponding highly-accurate grid-based numerical solutions of continuum equations. Both transient and stationary smooth particle solutions reproduce the grid-based data with velocity errors on the order of 5%. The smooth particle method still provides robust solutions at high Rayleigh number where grid-based methods fails.

  10. Fourier phase in Fourier-domain optical coherence tomography

    Science.gov (United States)

    Uttam, Shikhar; Liu, Yang

    2015-01-01

    Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided. PMID:26831383

  11. Fourier phase in Fourier-domain optical coherence tomography.

    Science.gov (United States)

    Uttam, Shikhar; Liu, Yang

    2015-12-01

    Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided.

  12. Gene expression model (invalidation by Fourier analysis

    Directory of Open Access Journals (Sweden)

    Konopka Tomasz

    2010-09-01

    Full Text Available Abstract Background The determination of the right model structure describing a gene regulation network and the identification of its parameters are major goals in systems biology. The task is often hampered by the lack of relevant experimental data with sufficiently low noise level, but the subset of genes whose concentration levels exhibit an oscillatory behavior in time can readily be analyzed on the basis of their Fourier spectrum, known to turn complex signals into few relatively noise-free parameters. Such genes therefore offer opportunities of understanding gene regulation quantitatively. Results Fourier analysis is applied to data on gene expression levels in mouse liver cells that oscillate according to the circadian rhythm. Several model structures in the form of linear and nonlinear differential equations are matched to the data and it is shown that although the considered models can reproduce many features of the oscillatory patterns, some can be excluded on the basis of Fourier analysis without appeal to prior knowledge of regulatory pathways. A systematic method for testing models is also proposed based on measuring the effects of variations in gene copy-number on the expression levels of coupled genes. Conclusions Fourier analysis is a technique that is well-adapted to the study of biological oscillators and can be used instead or in addition to conventional modeling techniques. Its usefulness will increase as more high-resolution data become available.

  13. Fourier analysis and stochastic processes

    CERN Document Server

    Brémaud, Pierre

    2014-01-01

    This work is unique as it provides a uniform treatment of the Fourier theories of functions (Fourier transforms and series, z-transforms), finite measures (characteristic functions, convergence in distribution), and stochastic processes (including arma series and point processes). It emphasises the links between these three themes. The chapter on the Fourier theory of point processes and signals structured by point processes is a novel addition to the literature on Fourier analysis of stochastic processes. It also connects the theory with recent lines of research such as biological spike signals and ultrawide-band communications. Although the treatment is mathematically rigorous, the convivial style makes the book accessible to a large audience. In particular, it will be interesting to anyone working in electrical engineering and communications, biology (point process signals) and econometrics (arma models). A careful review of the prerequisites (integration and probability theory in the appendix, Hilbert spa...

  14. Fourier analysis and synthesis tomography.

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Kelvin H. (University of Colorado at Boulder, Boulder, CO); Sinclair, Michael B.; Feldkuhn, Daniel (University of Colorado at Boulder, Boulder, CO)

    2010-05-01

    Most far-field optical imaging systems rely on a lens and spatially-resolved detection to probe distinct locations on the object. We describe and demonstrate a novel high-speed wide-field approach to imaging that instead measures the complex spatial Fourier transform of the object by detecting its spatially-integrated response to dynamic acousto-optically synthesized structured illumination. Tomographic filtered backprojection is applied to reconstruct the object in two or three dimensions. This technique decouples depth-of-field and working-distance from resolution, in contrast to conventional imaging, and can be used to image biological and synthetic structures in fluoresced or scattered light employing coherent or broadband illumination. We discuss the electronically programmable transfer function of the optical system and its implications for imaging dynamic processes. Finally, we present for the first time two-dimensional high-resolution image reconstructions demonstrating a three-orders-of-magnitude improvement in depth-of-field over conventional lens-based microscopy.

  15. Fractional Fourier processing of quantum light

    National Research Council Canada - National Science Library

    Sun, Yifan; Tao, Ran; Zhang, Xiangdong

    2014-01-01

    We have extended Fourier transform of quantum light to a fractional Fourier processing, and demonstrated that a classical optical fractional Fourier processor can be used for the shaping of quantum...

  16. Fourier reconstruction with sparse inversions

    OpenAIRE

    Zwartjes, P.M.

    2005-01-01

    In seismic exploration an image of the subsurface is generated from seismic data through various data processing algorithms. When the data is not acquired on an equidistantly spaced grid, artifacts may result in the final image. Fourier reconstruction is an interpolation technique that can reduce these artifacts by generating uniformly sampled data from such non-uniformly sampled data. The method works by estimating via least-squares inversion the Fourier coefficients that describe the non-un...

  17. On the Nonequilibrium Interface Kinetics of Rapid Coupled Eutectic Growth

    Science.gov (United States)

    Dong, H.; Chen, Y. Z.; Shan, G. B.; Zhang, Z. R.; Liu, F.

    2017-08-01

    Nonequilibrium interface kinetics (NEIK) is expected to play an important role in coupled growth of eutectic alloys, when solidification velocity is high and intermetallic compound or topologically complex phases form in the crystallized product. In order to quantitatively evaluate the effect of NEIK on the rapid coupled eutectic growth, in this work, two nonequilibrium interface kinetic effects, i.e., atom attachment and solute trapping at the solid-liquid interface, were incorporated into the analyses of the coupled eutectic growth under the rapid solidification condition. First, a coupled growth model incorporating the preceding two nonequilibrium kinetic effects was derived. On this basis, an expression of kinetic undercooling (∆ T k), which is used to characterize the NEIK, was defined. The calculations based on the as-derived couple growth model show good agreement with the reported experimental results achieved in rapidly solidified eutectic Al-Sm alloys consisting of a solid solution phase ( α-Al) and an intermetallic compound phase (Al11Sm3). In terms of the definition of ∆ T k defined in this work, the role of NEIK in the coupled growth of the Al-Sm eutectic system was analyzed. The results show that with increasing the coupled growth velocity, ∆ T k increases continuously, and its ratio to the total undercooling reaches 0.32 at the maximum growth velocity for coupled eutectic growth. Parametric analyses on two key alloy parameters that influence ∆ T k, i.e., interface kinetic parameter ( μ i ) and solute distribution coefficient ( k e ), indicate that both μ i and k e influence the NEIK significantly and the decrease of either these two parameters enhances the NEIK effect.

  18. Nonequilibrium solidification in undercooled Ti45Al55 melts

    Science.gov (United States)

    Hartmann, H.; Galenko, P. K.; Holland-Moritz, D.; Kolbe, M.; Herlach, D. M.; Shuleshova, O.

    2008-04-01

    Ti-Al alloys are of high technological interest as light-weight high-performance materials. When produced by solidification from the liquid state, the material properties of as-solidified materials are strongly dependent on the conditions governing the solidification process. Nonequilibrium solidification from the state of an undercooled liquid may result to the formation of metastable solid materials. On the one hand undercooling under special cases may influence the phase selection behavior during solidification, and on the other hand during rapid growth of solid phases in undercooled melts nonequilibrium effects such as solute trapping and disorder trapping may occur. In the present work containerless processing by electromagnetic levitation is used to undercool Ti45Al55 melts deeply below the liquidus temperature. The dendrite growth velocity during the solidification is measured as a function of undercooling by application of a high-speed video camera. In situ diffraction experiments at ESRF in Grenoble and microstructure investigations are performed in order to identify the primary solidified phases. The experimental findings are interpreted within current theoretical models for dendritic growth and solute trapping.

  19. Thermal stabilization of static single-mirror Fourier transform spectrometers

    Science.gov (United States)

    Schardt, Michael; Schwaller, Christian; Tremmel, Anton J.; Koch, Alexander W.

    2017-05-01

    Fourier transform spectroscopy has become a standard method for spectral analysis of infrared light. With this method, an interferogram is created by two beam interference which is subsequently Fourier-transformed. Most Fourier transform spectrometers used today provide the interferogram in the temporal domain. In contrast, static Fourier transform spectrometers generate interferograms in the spatial domain. One example of this type of spectrometer is the static single-mirror Fourier transform spectrometer which offers a high etendue in combination with a simple, miniaturized optics design. As no moving parts are required, it also features a high vibration resistance and high measurement rates. However, it is susceptible to temperature variations. In this paper, we therefore discuss the main sources for temperature-induced errors in static single-mirror Fourier transform spectrometers: changes in the refractive index of the optical components used, variations of the detector sensitivity, and thermal expansion of the housing. As these errors manifest themselves in temperature-dependent wavenumber shifts and intensity shifts, they prevent static single-mirror Fourier transform spectrometers from delivering long-term stable spectra. To eliminate these shifts, we additionally present a work concept for the thermal stabilization of the spectrometer. With this stabilization, static single-mirror Fourier transform spectrometers are made suitable for infrared process spectroscopy under harsh thermal environmental conditions. As the static single-mirror Fourier transform spectrometer uses the so-called source-doubling principle, many of the mentioned findings are transferable to other designs of static Fourier transform spectrometers based on the same principle.

  20. Identification of chemical components in Baidianling Capsule based on gas chromatography-mass spectrometry and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Wu, Wenying; Chen, Yu; Wang, Binjie; Sun, Xiaoyang; Guo, Ping; Chen, Xiaohui

    2017-08-01

    Baidianling Capsule, which is made from 16 Chinese herbs, has been widely used for treating vitiligo clinically. In this study, the sensitive and rapid method has been developed for the analysis of chemical components in Baidianling Capsule by gas chromatography-mass spectrometry in combination with retention indices and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Firstly, a total of 110 potential volatile compounds obtained from different extraction procedures including alkanes, alkenes, alkynes, ketones, ethers, aldehydes, alcohols, phenols, organic acids, esters, furans, pyrrole, acid amides, heterocycles, and oxides were detected from Baidianling Capsule by gas chromatography-mass spectrometry, of which 75 were identified by mass spectrometry in combination with the retention index. Then, a total of 124 components were tentatively identified by high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Fifteen constituents from Baidianling Capsule were accurately identified by comparing the retention times with those of reference compounds, others were identified by comparing the retention times and mass spectrometry data, as well as retrieving the reference literature. This study provides a practical strategy for rapidly screening and identifying the multiple constituents of a complex traditional Chinese medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Non-equilibrium phase behavior and friction of confined molecular films under shear: A non-equilibrium molecular dynamics study.

    Science.gov (United States)

    Maćkowiak, Sz; Heyes, D M; Dini, D; Brańka, A C

    2016-10-28

    The phase behavior of a confined liquid at high pressure and shear rate, such as is found in elastohydrodynamic lubrication, can influence the traction characteristics in machine operation. Generic aspects of this behavior are investigated here using Non-equilibrium Molecular Dynamics (NEMD) simulations of confined Lennard-Jones (LJ) films under load with a recently proposed wall-driven shearing method without wall atom tethering [C. Gattinoni et al., Phys. Rev. E 90, 043302 (2014)]. The focus is on thick films in which the nonequilibrium phases formed in the confined region impact on the traction properties. The nonequilibrium phase and tribological diagrams are mapped out in detail as a function of load, wall sliding speed, and atomic scale surface roughness, which is shown can have a significant effect. The transition between these phases is typically not sharp as the external conditions are varied. The magnitude of the friction coefficient depends strongly on the nonequilibrium phase adopted by the confined region of molecules, and in general does not follow the classical friction relations between macroscopic bodies, e.g., the frictional force can decrease with increasing load in the Plug-Slip (PS) region of the phase diagram owing to structural changes induced in the confined film. The friction coefficient can be extremely low (∼0.01) in the PS region as a result of incommensurate alignment between a (100) face-centered cubic wall plane and reconstructed (111) layers of the confined region near the wall. It is possible to exploit hysteresis to retain low friction PS states well into the central localization high wall speed region of the phase diagram. Stick-slip behavior due to periodic in-plane melting of layers in the confined region and subsequent annealing is observed at low wall speeds and moderate external loads. At intermediate wall speeds and pressure values (at least) the friction coefficient decreases with increasing well depth of the LJ potential

  2. PREFACE: Progress in Nonequilibrium Green's Functions V (PNGF V)

    Science.gov (United States)

    van Leeuwen, Robert; Tuovinen, Riku; Bonitz, Michael

    2013-03-01

    (The PDF contains: an obituary and in memoriam for David C. Langreth, a list of the conference participants, a complete list of the conference talks and posters and several photographs taken during the conference. ) The fifth interdisciplinary conference 'Progress in Nonequilibrium Green's Functions' (PNGF5) was held at the University of Jyväskylä, Finland, on 27--31 August 2012. The conference continued the successful tradition of its predecessors (Rostock 1999, Dresden 2002, Kiel 2005 and Glasgow 2009) to bring together different communities for an interdisciplinary exchange of recent results and theoretical concepts. The conference focused on recent developments, current challenges and future perspectives in nonequilibrium Green's functions theory in various fields of physics but included also other many-body methods. Roughly 20 invited talks were given by some of the top scientists in the field, accompanied by 10 contributed talks. (Slides of several presentations can be found online at www.jyu.fi/physics/pngf5.) Also a poster session was set up to enhance scientific discussions, building up new collaborations and enriching views and ideas. As at the previous meetings, the atmosphere was interactive and stimulating, benefitting both experienced scientists and young researchers and students. The present volume contains 14 articles based on works presented at this conference. The articles partly have review character so they should be of use for an interdisciplinary community working or interested in nonequilibrium Green's functions. All papers were refereed according to high scientific standards. The conference would not have been possible without financial support from the Federation of Finnish Learned Societies, Finnish Academy of Science and Letters and Nanoscience Center of the university of Jyväskylä which are greatly acknowledged. The local organizing committee is also grateful to the administration personnel, Marjut Hilska and Riitta-Liisa Kuittinen

  3. Non-equilibrium theory of arrested spinodal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Olais-Govea, José Manuel; López-Flores, Leticia; Medina-Noyola, Magdaleno [Instituto de Física “Manuel Sandoval Vallarta,” Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, SLP (Mexico)

    2015-11-07

    The non-equilibrium self-consistent generalized Langevin equation theory of irreversible relaxation [P. E. Ramŕez-González and M. Medina-Noyola, Phys. Rev. E 82, 061503 (2010); 82, 061504 (2010)] is applied to the description of the non-equilibrium processes involved in the spinodal decomposition of suddenly and deeply quenched simple liquids. For model liquids with hard-sphere plus attractive (Yukawa or square well) pair potential, the theory predicts that the spinodal curve, besides being the threshold of the thermodynamic stability of homogeneous states, is also the borderline between the regions of ergodic and non-ergodic homogeneous states. It also predicts that the high-density liquid-glass transition line, whose high-temperature limit corresponds to the well-known hard-sphere glass transition, at lower temperature intersects the spinodal curve and continues inside the spinodal region as a glass-glass transition line. Within the region bounded from below by this low-temperature glass-glass transition and from above by the spinodal dynamic arrest line, we can recognize two distinct domains with qualitatively different temperature dependence of various physical properties. We interpret these two domains as corresponding to full gas-liquid phase separation conditions and to the formation of physical gels by arrested spinodal decomposition. The resulting theoretical scenario is consistent with the corresponding experimental observations in a specific colloidal model system.

  4. Nonequilibrium recombination after a curved shock wave

    Science.gov (United States)

    Wen, Chihyung; Hornung, Hans

    2010-02-01

    The effect of nonequilibrium recombination after a curved two-dimensional shock wave in a hypervelocity dissociating flow of an inviscid Lighthill-Freeman gas is considered. An analytical solution is obtained with the effective shock values derived by Hornung (1976) [5] and the assumption that the flow is ‘quasi-frozen’ after a thin dissociating layer near the shock. The solution gives the expression of dissociation fraction as a function of temperature on a streamline. A rule of thumb can then be provided to check the validity of binary scaling for experimental conditions and a tool to determine the limiting streamline that delineates the validity zone of binary scaling. The effects on the nonequilibrium chemical reaction of the large difference in free stream temperature between free-piston shock tunnel and equivalent flight conditions are discussed. Numerical examples are presented and the results are compared with solutions obtained with two-dimensional Euler equations using the code of Candler (1988) [10].

  5. Nonequilibrium thermal entanglement for simple spin chains

    Science.gov (United States)

    Sinayskiy, I.; Pumulo, N.; Petruccione, F.

    2012-09-01

    The dynamics of a chain of two and three spins coupled at both ends to separate bosonic baths at different temperatures is studied. An exact analytical solution of the quantum master equation in the Born-Markov approximation for the reduced density matrix of the chain is constructed. It is shown that for long times the reduced density matrix converges to the nonequilibrium steady-state. Dynamical and steady state properties of the concurrence between the first and the last spin are studied.

  6. Lattice Boltzmann approach for complex nonequilibrium flows.

    Science.gov (United States)

    Montessori, A; Prestininzi, P; La Rocca, M; Succi, S

    2015-10-01

    We present a lattice Boltzmann realization of Grad's extended hydrodynamic approach to nonequilibrium flows. This is achieved by using higher-order isotropic lattices coupled with a higher-order regularization procedure. The method is assessed for flow across parallel plates and three-dimensional flows in porous media, showing excellent agreement of the mass flow with analytical and numerical solutions of the Boltzmann equation across the full range of Knudsen numbers, from the hydrodynamic regime to ballistic motion.

  7. Nonequilibrium functional bosonization of quantum wire networks

    Energy Technology Data Exchange (ETDEWEB)

    Ngo Dinh, Stephane, E-mail: stephane.ngodinh@kit.edu [Institut fuer Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); DFG Center for Functional Nanostructures, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Bagrets, Dmitry A. [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany); Mirlin, Alexander D. [Institut fuer Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Institut fuer Nanotechnologie, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Petersburg Nuclear Physics Institute, 188300 St. Petersburg (Russian Federation)

    2012-11-15

    We develop a general approach to nonequilibrium nanostructures formed by one-dimensional channels coupled by tunnel junctions and/or by impurity scattering. The formalism is based on nonequilibrium version of functional bosonization. A central role in this approach is played by the Keldysh action that has a form reminiscent of the theory of full counting statistics. To proceed with evaluation of physical observables, we assume the weak-tunneling regime and develop a real-time instanton method. A detailed exposition of the formalism is supplemented by two important applications: (i) tunneling into a biased Luttinger liquid with an impurity, and (ii) quantum Hall Fabry-Perot interferometry. - Highlights: Black-Right-Pointing-Pointer A nonequilibrium functional bosonization framework for quantum wire networks is developed Black-Right-Pointing-Pointer For the study of observables in the weak tunneling regime a real-time instanton method is elaborated. Black-Right-Pointing-Pointer We consider tunneling into a biased Luttinger liquid with an impurity. Black-Right-Pointing-Pointer We analyze electronic Fabry-Perot interferometers in the integer quantum Hall regime.

  8. High resolution spectroscopy in the second excited torsional state of $CH_{3}/OD$ and the atlas of the Fourier transform spectrum in the range 20-205 cm$^{-1}/$...

    CERN Document Server

    Mukhopadhyay, I

    1999-01-01

    In this work, the reduced eighth order Hamiltonian that has been used for the determination of the molecular parameters-using the high resolution Fourier transform far-infrared (FIR) assigned transitions in the ground and first $9 excited torsional states of CH/sub 3/OD-has been applied to assign and refine the model for the second excited torsional state. The data set consisted of 1220 FIR transitions with the rotational angular momentum J<21 and K<7 in the $9 second excited torsional state. It should be noted that the second excited torsional states of methanol are almost at the top of the torsional barrier. Thus it was interesting to see how the large amplitude motion is taken care of by $9 the eighth order Hamiltonian. We are in the process of a global fit including all the assigned transitions up to the second excited state. Additionally, in this paper we present the detailed Fourier transform spectral map of CH/sub $9 3/OD in the range 20-205 cm/sup -1/, as was done for the parent species. This sp...

  9. Ab initio nonequilibrium quantum transport and forces with the real-space projector augmented wave method

    DEFF Research Database (Denmark)

    Chen, Jingzhe; Thygesen, Kristian S.; Jacobsen, Karsten W.

    2012-01-01

    over k points and real space makes the code highly efficient and applicable to systems containing several hundreds of atoms. The method is applied to a number of different systems, demonstrating the effects of bias and gate voltages, multiterminal setups, nonequilibrium forces, and spin transport....

  10. Probing large viscosities in glass-formers with nonequilibrium simulations

    Science.gov (United States)

    Jadhao, Vikram; Robbins, Mark O.

    2017-07-01

    For decades, scientists have debated whether supercooled liquids stop flowing below a glass transition temperature Tg0 or whether motion continues to slow gradually down to zero temperature. Answering this question is challenging because human time scales set a limit on the largest measurable viscosity, and available data are equally well fit to models with opposite conclusions. Here, we use short simulations to determine the nonequilibrium shear response of a typical glass-former, squalane. Fits of the data to an Eyring model allow us to extrapolate predictions for the equilibrium Newtonian viscosity ηN over a range of pressures and temperatures that change ηN by 25 orders of magnitude. The results agree with the unusually large set of equilibrium and nonequilibrium experiments on squalane and extend them to higher ηN. Studies at different pressures and temperatures are inconsistent with a diverging viscosity at finite temperature. At all pressures, the predicted viscosity becomes Arrhenius with a single temperature-independent activation barrier at low temperatures and high viscosities (ηN>103 Pa ṡs). Possible experimental tests of our results are outlined.

  11. The Geostationary Fourier Transform Spectrometer

    Science.gov (United States)

    Key, Richard; Sander, Stanley; Eldering, Annmarie; Blavier, Jean-Francois; Bekker, Dmitriy; Manatt, Ken; Rider, David; Wu, Yen-Hung

    2012-01-01

    The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for a geostationary orbit (GEO) earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. GEO allows GeoFTS to continuously stare at a region of the earth for frequent sampling to capture the variability of biogenic fluxes and anthropogenic emissions from city to continental spatial scales and temporal scales from diurnal, synoptic, seasonal to interannual. The measurement strategy provides a process based understanding of the carbon cycle from contiguous maps of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) collected many times per day at high spatial resolution (2.7kmx2.7km at nadir). The CO2/CH4/CO/CF measurement suite in the near infrared spectral region provides the information needed to disentangle natural and anthropogenic contributions to atmospheric carbon concentrations and to minimize uncertainties in the flow of carbon between the atmosphere and surface. The half meter cube size GeoFTS instrument is based on a Michelson interferometer design that uses all high TRL components in a modular configuration to reduce complexity and cost. It is self-contained and as independent of the spacecraft as possible with simple spacecraft interfaces, making it ideal to be a "hosted" payload on a commercial communications satellite mission. The hosted payload approach for measuring the major carbon-containing gases in the atmosphere from the geostationary vantage point will affordably advance the scientific understating of carbon cycle processes and climate change.

  12. General Correlation Theorem for Trinion Fourier Transform

    OpenAIRE

    Bahri, Mawardi

    2017-01-01

    - The trinion Fourier transform is an extension of the Fourier transform in the trinion numbers setting. In this work we derive the correlation theorem for the trinion Fourier transform by using the relation between trinion convolution and correlation definitions in the trinion Fourier transform domains.

  13. Fourier Series, the DFT and Shape Modelling

    DEFF Research Database (Denmark)

    Skoglund, Karl

    2004-01-01

    This report provides an introduction to Fourier series, the discrete Fourier transform, complex geometry and Fourier descriptors for shape analysis. The content is aimed at undergraduate and graduate students who wish to learn about Fourier analysis in general, as well as its application to shape...

  14. Fourier Transform Fabry-Perot Interferometer

    Science.gov (United States)

    Snell, Hilary E.; Hays, Paul B.

    1992-01-01

    We are developing a compact, rugged, high-resolution remote sensing instrument with wide spectral scanning capabilities. This relatively new type of instrument, which we have chosen to call the Fourier-Transform Fabry-Perot Interferometer (FT-FPI), is accomplished by mechanically scanning the etalon plates of a Fabry-Perot interferometer (FPI) through a large optical distance while examining the concomitant signal with a Fourier-transform analysis technique similar to that employed by the Michelson interferometer. The FT-FPI will be used initially as a ground-based instrument to study near-infrared atmospheric absorption lines of trace gases using the techniques of solar absorption spectroscopy. Future plans include modifications to allow for measurements of trace gases in the stratosphere using spectral lines at terahertz frequencies.

  15. Fourier series, Fourier transform and their applications to mathematical physics

    CERN Document Server

    Serov, Valery

    2017-01-01

    This text serves as an introduction to the modern theory of analysis and differential equations with applications in mathematical physics and engineering sciences.  Having outgrown from a series of half-semester courses given at University of Oulu, this book consists of four self-contained parts. The first part, Fourier Series and the Discrete Fourier Transform, is devoted to the classical one-dimensional trigonometric Fourier series with some applications to PDEs and signal processing.  The second part, Fourier Transform and Distributions, is concerned with distribution theory of L. Schwartz and its applications to the Schrödinger and magnetic Schrödinger operations.  The third part, Operator Theory and Integral Equations, is devoted mostly to the self-adjoint but unbounded operators in Hilbert spaces and their applications to integral equations in such spaces. The fourth and final part, Introduction to Partial Differential Equations, serves as an introduction to modern methods for classical theory o...

  16. Synthetic Fourier transform light scattering.

    Science.gov (United States)

    Lee, Kyeoreh; Kim, Hyeon-Don; Kim, Kyoohyun; Kim, Youngchan; Hillman, Timothy R; Min, Bumki; Park, Yongkeun

    2013-09-23

    We present synthetic Fourier transform light scattering, a method for measuring extended angle-resolved light scattering (ARLS) from individual microscopic samples. By measuring the light fields scattered from the sample plane and numerically synthesizing them in Fourier space, the angle range of the ARLS patterns is extended up to twice the numerical aperture of the imaging system with unprecedented sensitivity and precision. Extended ARLS patterns of individual microscopic polystyrene beads, healthy human red blood cells (RBCs), and Plasmodium falciparum-parasitized RBCs are presented.

  17. Fourier series in orthogonal polynomials

    CERN Document Server

    Osilenker, Boris

    1999-01-01

    This book presents a systematic course on general orthogonal polynomials and Fourier series in orthogonal polynomials. It consists of six chapters. Chapter 1 deals in essence with standard results from the university course on the function theory of a real variable and on functional analysis. Chapter 2 contains the classical results about the orthogonal polynomials (some properties, classical Jacobi polynomials and the criteria of boundedness).The main subject of the book is Fourier series in general orthogonal polynomials. Chapters 3 and 4 are devoted to some results in this topic (classical

  18. Non-equilibrium between ions and electrons inside hot spots from National Ignition Facility experiments

    Directory of Open Access Journals (Sweden)

    Zhengfeng Fan

    2017-01-01

    Full Text Available The non-equilibrium between ions and electrons in the hot spot can relax the ignition conditions in inertial confinement fusion [Fan et al., Phys. Plasmas 23, 010703 (2016], and obvious ion-electron non-equilibrium could be observed by our simulations of high-foot implosions when the ion-electron relaxation is enlarged by a factor of 2. On the other hand, in many shots of high-foot implosions on the National Ignition Facility, the observed X-ray enhancement factors due to ablator mixing into the hot spot are less than unity assuming electrons and ions have the same temperature [Meezan et al., Phys. Plasmas 22, 062703 (2015], which is not self-consistent because it can lead to negative ablator mixing into the hot spot. Actually, this non-consistency implies ion-electron non-equilibrium within the hot spot. From our study, we can infer that ion-electron non-equilibrium exists in high-foot implosions and the ion temperature could be ∼9% larger than the equilibrium temperature in some NIF shots.

  19. Nonequilibrium Segregation in Petroleum Reservoirs

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1999-01-01

    We analyse adsorption of a multicomponent mixture at high pressure on the basis of the potential theory of adsorption. The adsorbate is considered as a segregated mixture in the external field produced by a solid adsorbent. we derive an analytical equation for the thickness of a multicomponent film...

  20. Absolute FKBP binding affinities obtained via nonequilibrium unbinding simulations.

    Science.gov (United States)

    Ytreberg, F Marty

    2009-04-28

    We compute the absolute binding affinities for two ligands bound to the FKBP protein using nonequilibrium unbinding simulations. The methodology is straightforward requiring little or no modification to many modern molecular simulation packages. The approach makes use of a physical pathway, eliminating the need for complicated alchemical decoupling schemes. We compare our nonequilibrium results to those obtained via a fully equilibrium approach and to experiment. The results of this study suggest that to obtain accurate results using nonequilibrium approaches one should use the stiff-spring approximation with the second cumulant expansion. From this study we conclude that nonequilibrium simulation could provide a simple means to estimate protein-ligand binding affinities.

  1. Uncertainty Principles and Fourier Analysis

    Indian Academy of Sciences (India)

    meta-theorem in harmonic analysis that can be summarized as follows: A nonzero function and its Fourier transform cannot both be sharply localized." I t is the last part of the paragraph that is the raison d 'etre for the mathematician's interest in uncertainty principles. Another way to express the meta uncertainty principle is: A.

  2. Non-equilibrium dissipative supramolecular materials with a tunable lifetime

    Science.gov (United States)

    Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job

    2017-07-01

    Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.

  3. Generalized Dicke Nonequilibrium Dynamics in Trapped Ions

    Science.gov (United States)

    Genway, Sam; Li, Weibin; Ates, Cenap; Lanyon, Benjamin P.; Lesanovsky, Igor

    2014-01-01

    We explore trapped ions as a setting to investigate nonequilibrium phases in a generalized Dicke model of dissipative spins coupled to phonon modes. We find a rich dynamical phase diagram including superradiantlike regimes, dynamical phase coexistence, and phonon-lasing behavior. A particular advantage of trapped ions is that these phases and transitions among them can be probed in situ through fluorescence. We demonstrate that the main physical insights are captured by a minimal model and consider an experimental realization with Ca+ ions trapped in a linear Paul trap with a dressing scheme to create effective two-level systems with a tunable dissipation rate.

  4. Nonequilibrium thermodynamics and Nose-Hoover dynamics.

    Science.gov (United States)

    Esposito, Massimiliano; Monnai, Takaaki

    2011-05-12

    We show that systems driven by an external force and described by Nose-Hoover dynamics allow for a consistent nonequilibrium thermodynamics description when the thermostatted variable is initially assumed in a state of canonical equilibrium. By treating the "real" variables as the system and the thermostatted variable as the reservoir, we establish the first and second law of thermodynamics. As for Hamiltonian systems, the entropy production can be expressed as a relative entropy measuring the system-reservoir correlations established during the dynamics.

  5. Non-equilibrium Dynamics of DNA Nanotubes

    Science.gov (United States)

    Hariadi, Rizal Fajar

    Can the fundamental processes that underlie molecular biology be understood and simulated by DNA nanotechnology? The early development of DNA nanotechnology by Ned Seeman was driven by the desire to find a solution to the protein crystallization problem. Much of the later development of the field was also driven by envisioned applications in computing and nanofabrication. While the DNA nanotechnology community has assembled a versatile tool kit with which DNA nanostructures of considerable complexity can be assembled, the application of this tool kit to other areas of science and technology is still in its infancy. This dissertation reports on the construction of non-equilibrium DNA nanotube dynamic to probe molecular processes in the areas of hydrodynamics and cytoskeletal behavior. As the first example, we used DNA nanotubes as a molecular probe for elongational flow measurement in different micro-scale flow settings. The hydrodynamic flow in the vicinity of simple geometrical objects, such as a rigid DNA nanotube, is amenable to rigorous theoretical investigation. We measured the distribution of elongational flows produced in progressively more complex settings, ranging from the vicinity of an orifice in a microfluidic chamber to within a bursting bubble of Pacific ocean water. This information can be used to constrain theories on the origin of life in which replication involves a hydrodynamically driven fission process, such as the coacervate fission proposed by Oparin. A second theme of this dissertation is the bottom-up construction of a de novo artificial cytoskeleton with DNA nanotubes. The work reported here encompasses structural, locomotion, and control aspects of non-equilibrium cytoskeletal behavior. We first measured the kinetic parameters of DNA nanotube assembly and tested the accuracy of the existing polymerization models in the literature. Toward recapitulation of non-equilibrium cytoskeletal dynamics, we coupled the polymerization of DNA

  6. Ab initio vibrations in nonequilibrium nanowires

    DEFF Research Database (Denmark)

    Jauho, Antti-Pekka; Engelund, Mads; Markussen, T

    2010-01-01

    predictions for the thermoelectric properties, while for the atomic gold chains we evaluate microscopically the damping of the vibrations, due to the coupling of the chain atoms to the modes in the bulk contacts. Both approaches are based on the combination of density-functional theory, and nonequilibrium......We review recent results on electronic and thermal transport in two different quasi one-dimensional systems: Silicon nanowires (SiNW) and atomic gold chains. For SiNW's we compute the ballistic electronic and thermal transport properties on equal footing, allowing us to make quantitative...

  7. Spectroscopy of nonequilibrium electrons and phonons

    CERN Document Server

    Shank, CV

    1992-01-01

    The physics of nonequilibrium electrons and phonons in semiconductors is an important branch of fundamental physics that has many practical applications, especially in the development of ultrafast and ultrasmall semiconductor devices. This volume is devoted to different trends in the field which are presently at the forefront of research. Special attention is paid to the ultrafast relaxation processes in bulk semiconductors and two-dimensional semiconductor structures, and to their study by different spectroscopic methods, both pulsed and steady-state. The evolution of energy and space distrib

  8. Universality in Nonequilibrium Lattice Systems Theoretical Foundations

    CERN Document Server

    Ódor, Géza

    2008-01-01

    Universal scaling behavior is an attractive feature in statistical physics because a wide range of models can be classified purely in terms of their collective behavior due to a diverging correlation length. This book provides a comprehensive overview of dynamical universality classes occurring in nonequilibrium systems defined on regular lattices. The factors determining these diverse universality classes have yet to be fully understood, but the book attempts to summarize our present knowledge, taking them into account systematically.The book helps the reader to navigate in the zoo of basic m

  9. Nonequilibrium quantum thermodynamics in Coulomb crystals

    Science.gov (United States)

    Cosco, F.; Borrelli, M.; Silvi, P.; Maniscalco, S.; De Chiara, G.

    2017-06-01

    We present an in-depth study of the nonequilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the nonanalytic behavior of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped-ion experiments, our results can be readily verified.

  10. Use of Fourier domain filtering and dynamic programming in finding a titanium coil implant in high voltage x-ray images

    DEFF Research Database (Denmark)

    Nielsen, Henning; Hansen, Jesper Carl

    2006-01-01

    This paper deals with the problem of finding precise position and orientation of a titanium coil implant in humans. Analysis of high voltage X-rays stereo images are used to determine the true 3D position. High voltage images inherently presents with poor contrast. Various image processing...

  11. Fourier analysis for rotating-element ellipsometers.

    Science.gov (United States)

    Cho, Yong Jai; Chegal, Won; Cho, Hyun Mo

    2011-01-15

    We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions. Unlike the Hadamard transform, a well-known data acquisition method that is used only for conventional multichannel rotating-element ellipsometers with line arrays with specific readout-mode timing, this Fourier analysis is applicable to various line arrays with either nonoverlap or overlap readout-mode timing. To assess the effects of the novel Fourier analysis, the Fourier coefficients for a sample were measured with a custom-built rotating-polarizer ellipsometer, using this Fourier analysis with various numbers of scans, integration times, and rotational speeds of the polarizer.

  12. Nonequilibrium Thermodynamics in Biological Systems

    Science.gov (United States)

    Aoki, I.

    2005-12-01

    1. Respiration Oxygen-uptake by respiration in organisms decomposes macromolecules such as carbohydrate, protein and lipid and liberates chemical energy of high quality, which is then used to chemical reactions and motions of matter in organisms to support lively order in structure and function in organisms. Finally, this chemical energy becomes heat energy of low quality and is discarded to the outside (dissipation function). Accompanying this heat energy, entropy production which inevitably occurs by irreversibility also is discarded to the outside. Dissipation function and entropy production are estimated from data of respiration. 2. Human body From the observed data of respiration (oxygen absorption), the entropy production in human body can be estimated. Entropy production from 0 to 75 years old human has been obtained, and extrapolated to fertilized egg (beginning of human life) and to 120 years old (maximum period of human life). Entropy production show characteristic behavior in human life span : early rapid increase in short growing phase and later slow decrease in long aging phase. It is proposed that this tendency is ubiquitous and constitutes a Principle of Organization in complex biotic systems. 3. Ecological communities From the data of respiration of eighteen aquatic communities, specific (i.e. per biomass) entropy productions are obtained. They show two phase character with respect to trophic diversity : early increase and later decrease with the increase of trophic diversity. The trophic diversity in these aquatic ecosystems is shown to be positively correlated with the degree of eutrophication, and the degree of eutrophication is an "arrow of time" in the hierarchy of aquatic ecosystems. Hence specific entropy production has the two phase: early increase and later decrease with time. 4. Entropy principle for living systems The Second Law of Thermodynamics has been expressed as follows. 1) In isolated systems, entropy increases with time and

  13. Implementation of weighted summation type fractional Fourier transform on FPGA

    Science.gov (United States)

    Zou, Qiming; Li, Longlong; Huang, Qian; Wang, Fei

    2015-07-01

    Recently Fractional Fourier transform (FrFT) has got a variety of applications in digital signal and image processing. This paper presents a novel hardware architecture for real-time computation of Discrete Fractional Fourier Transform (DFrFT), which can easily be extended to other fractional transforms. The proposed architecture has been verified on Xilinx FPGA(XC6VLX240T), which can run at a frequency up to 291MHz while with high accuracy.

  14. A multi-component discrete Boltzmann model for nonequilibrium reactive flows.

    Science.gov (United States)

    Lin, Chuandong; Luo, Kai Hong; Fei, Linlin; Succi, Sauro

    2017-11-06

    We propose a multi-component discrete Boltzmann model (DBM) for premixed, nonpremixed, or partially premixed nonequilibrium reactive flows. This model is suitable for both subsonic and supersonic flows with or without chemical reaction and/or external force. A two-dimensional sixteen-velocity model is constructed for the DBM. In the hydrodynamic limit, the DBM recovers the modified Navier-Stokes equations for reacting species in a force field. Compared to standard lattice Boltzmann models, the DBM presents not only more accurate hydrodynamic quantities, but also detailed nonequilibrium effects that are essential yet long-neglected by traditional fluid dynamics. Apart from nonequilibrium terms (viscous stress and heat flux) in conventional models, specific hydrodynamic and thermodynamic nonequilibrium quantities (high order kinetic moments and their departure from equilibrium) are dynamically obtained from the DBM in a straightforward way. Due to its generality, the developed methodology is applicable to a wide range of phenomena across many energy technologies, emissions reduction, environmental protection, mining accident prevention, chemical and process industry.

  15. Nonequilibrium candidate Monte Carlo is an efficient tool for equilibrium simulation

    Energy Technology Data Exchange (ETDEWEB)

    Nilmeier, J. P.; Crooks, G. E.; Minh, D. D. L.; Chodera, J. D.

    2011-10-24

    Metropolis Monte Carlo simulation is a powerful tool for studying the equilibrium properties of matter. In complex condensed-phase systems, however, it is difficult to design Monte Carlo moves with high acceptance probabilities that also rapidly sample uncorrelated configurations. Here, we introduce a new class of moves based on nonequilibrium dynamics: candidate configurations are generated through a finite-time process in which a system is actively driven out of equilibrium, and accepted with criteria that preserve the equilibrium distribution. The acceptance rule is similar to the Metropolis acceptance probability, but related to the nonequilibrium work rather than the instantaneous energy difference. Our method is applicable to sampling from both a single thermodynamic state or a mixture of thermodynamic states, and allows both coordinates and thermodynamic parameters to be driven in nonequilibrium proposals. While generating finite-time switching trajectories incurs an additional cost, driving some degrees of freedom while allowing others to evolve naturally can lead to large enhancements in acceptance probabilities, greatly reducing structural correlation times. Using nonequilibrium driven processes vastly expands the repertoire of useful Monte Carlo proposals in simulations of dense solvated systems.

  16. Modelling non-equilibrium thermodynamic systems from the speed-gradient principle.

    Science.gov (United States)

    Khantuleva, Tatiana A; Shalymov, Dmitry S

    2017-03-06

    The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).

  17. Non-equilibrium phase transitions in complex plasma

    NARCIS (Netherlands)

    Sutterlin, K. R.; Wysocki, A.; Rath, C.; Ivlev, A. V.; Thomas, H. M.; Khrapak, S.; Zhdanov, S.; Rubin-Zuzic, M.; W. J. Goedheer,; Fortov, V. E.; Lipaev, A. M.; Molotkov, V. I.; Petrov, O. F.; Morfill, G. E.; Lowen, H.

    2010-01-01

    Complex plasma being the 'plasma state of soft matter' is especially suitable for investigations of non-equilibrium phase transitions. Non-equilibrium phase transitions can manifest in dissipative structures or self-organization. Two specific examples are lane formation and phase

  18. Nonequilibrium dynamics in an interacting Fe-C nanoparticle system

    DEFF Research Database (Denmark)

    Jönsson, P.; Hansen, Mikkel Fougt; Nordblad, P.

    2000-01-01

    Nonequilibrium dynamics in an interacting Fe-C nanoparticle sample, exhibiting a low-temperature spin-glass-like phase, has been studied by low-frequency ac susceptibility and magnetic relaxation experiments. The nonequilibrium behavior shows characteristic spin-glass features, but some qualitative...

  19. Nonequilibrium dynamical mean-field theory

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Martin

    2009-12-21

    The aim of this thesis is the investigation of strongly interacting quantum many-particle systems in nonequilibrium by means of the dynamical mean-field theory (DMFT). An efficient numerical implementation of the nonequilibrium DMFT equations within the Keldysh formalism is provided, as well a discussion of several approaches to solve effective single-site problem to which lattice models such as the Hubbard-model are mapped within DMFT. DMFT is then used to study the relaxation of the thermodynamic state after a sudden increase of the interaction parameter in two different models: the Hubbard model and the Falicov-Kimball model. In the latter case an exact solution can be given, which shows that the state does not even thermalize after infinite waiting times. For a slow change of the interaction, a transition to adiabatic behavior is found. The Hubbard model, on the other hand, shows a very sensitive dependence of the relaxation on the interaction, which may be called a dynamical phase transition. Rapid thermalization only occurs at the interaction parameter which corresponds to this transition. (orig.)

  20. Nonequilibrium free diffusion in seed leachate

    Science.gov (United States)

    Ortiz G., Luis; Riquelme P., Pablo; Guzmán, R.

    2013-11-01

    In this work, we use a Schlieren-like Near Field Scattering (SNFS) setup to study nonequilibrium free diffusion behavior of a colloidal solution obtained from seeds leachate. The main objective is to compare the temporal behavior of the diffusion coefficient of seed leachate with an electric conductivity based vigor test. SNFS sizing measurements, based on Mie theory, were carried out to ensure its reliability and sensitivity. Then, we performed a typical nonequilibrium free diffusion experiment of a glycerol-water mixture. In this way, we confirmed that SNFS setup is sensitive to giant concentration fluctuations of nanocolloidal solutions. The results obtained in this stage reproduce properly the data reported elsewhere in literature. Moreover, seed leachate diffuse, in water, in a similar way that glycerol does. In both cases we used the same method (dynamic structure factor) to determine thermo-physical properties. We show that time evolution of diffusion coefficient of Lupinus Albus leachate exhibits three defined regimes as electric conductivity measurements. The results also exhibit a correspondence between the behavior of the diffusion coefficient and electric conductivity values of the two regions in the temporal range studied. Finally, we discuss biological processes involved in germination that could modulate this dependence, and the role played by the electrolytic nature of solutes.

  1. Non-equilibrium many body dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, M.; Gyulassy, M.

    1997-09-22

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop.

  2. Topologically protected modes in non-equilibrium stochastic systems

    Science.gov (United States)

    Murugan, Arvind; Vaikuntanathan, Suriyanarayanan

    2017-01-01

    Non-equilibrium driving of biophysical processes is believed to enable their robust functioning despite the presence of thermal fluctuations and other sources of disorder. Such robust functions include sensory adaptation, enhanced enzymatic specificity and maintenance of coherent oscillations. Elucidating the relation between energy consumption and organization remains an important and open question in non-equilibrium statistical mechanics. Here we report that steady states of systems with non-equilibrium fluxes can support topologically protected boundary modes that resemble similar modes in electronic and mechanical systems. Akin to their electronic and mechanical counterparts, topological-protected boundary steady states in non-equilibrium systems are robust and are largely insensitive to local perturbations. We argue that our work provides a framework for how biophysical systems can use non-equilibrium driving to achieve robust function.

  3. Thermal Non-equilibrium Consistent with Widespread Cooling

    Science.gov (United States)

    Winebarger, A.; Lionello, R.; Mikic, Z.; Linker, J.; Mok, Y.

    2014-01-01

    Time correlation analysis has been used to show widespread cooling in the solar corona; this cooling has been interpreted as a result of impulsive (nanoflare) heating. In this work, we investigate wide-spread cooling using a 3D model for a solar active region which has been heated with highly stratified heating. This type of heating drives thermal non-equilibrium solutions, meaning that though the heating is effectively steady, the density and temperature in the solution are not. We simulate the expected observations in narrowband EUV images and apply the time correlation analysis. We find that the results of this analysis are qualitatively similar to the observed data. We discuss additional diagnostics that may be applied to differentiate between these two heating scenarios.

  4. From Fourier analysis to wavelets

    CERN Document Server

    Gomes, Jonas

    2015-01-01

    This text introduces the basic concepts of function spaces and operators, both from the continuous and discrete viewpoints.  Fourier and Window Fourier Transforms are introduced and used as a guide to arrive at the concept of Wavelet transform.  The fundamental aspects of multiresolution representation, and its importance to function discretization and to the construction of wavelets is also discussed. Emphasis is given on ideas and intuition, avoiding the heavy computations which are usually involved in the study of wavelets.  Readers should have a basic knowledge of linear algebra, calculus, and some familiarity with complex analysis.  Basic knowledge of signal and image processing is desirable. This text originated from a set of notes in Portuguese that the authors wrote for a wavelet course on the Brazilian Mathematical Colloquium in 1997 at IMPA, Rio de Janeiro.

  5. From Fourier optics to integrative engineering

    Science.gov (United States)

    Jannson, Tomasz; Kostrzewski, Andrew

    2011-10-01

    In this paper we present technical evolution at Physical Optics Corporation (POC), from Fourier Optics, inspired by Professor Joseph Goodman's classic book: Introduction to Fourier Optics, to recent directions at POC, related to socalled "Integrative Engineering."

  6. An introduction to Fourier series and integrals

    CERN Document Server

    Seeley, Robert T

    2006-01-01

    This compact guide emphasizes the relationship between physics and mathematics, introducing Fourier series in the way that Fourier himself used them: as solutions of the heat equation in a disk. 1966 edition.

  7. Automated Data Reduction for Hydrogen/Deuterium Exchange Experiments, Enabled by High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Kazazic, Sasa; Zhang, Hui-Min; Schaub, Tanner M.; Emmett, Mark R.; Hendrickson, Christopher L.; Blakney, Gregory T.; Marshall, Alan G.

    2010-01-01

    Mass analysis of proteolytic fragment peptides following hydrogen/deuterium exchange offers a general measure of solvent accessibility/hydrogen bonding (and thus conformation) of solution-phase proteins and their complexes. The primary problem in such mass analyses is reliable and rapid assignment of mass spectral peaks to the correct charge state and degree of deuteration of each fragment peptide, in the presence of substantial overlap between isotopic distributions of target peptides, autolysis products, and other interferant species. Here, we show that at sufficiently high mass resolving power (m/Δm50% ≥ 100,000), it becomes possible to resolve enough of those overlaps so that automated data reduction becomes possible, based on the actual elemental composition of each peptide without the need to deconvolve isotopic distributions. We demonstrate automated, rapid, reliable assignment of peptide masses from H/D exchange experiments, based on electrospray ionization FT-ICR mass spectra from H/D exchange of solution-phase myoglobin. Combined with previously demonstrated automated data acquisition for such experiments, the present data reduction algorithm enhances automation (and thus expands generality and applicability) for high-resolution mass spectrometry- based analysis of H/D exchange of solution-phase proteins. PMID:20116280

  8. Fourier techniques in X-ray timing

    NARCIS (Netherlands)

    van der Klis, M.

    1988-01-01

    Basic principles of Fourier techniques often used in X-ray time series analysis are reviewed. The relation between the discrete Fourier transform and the continuous Fourier transform is discussed to introduce the concepts of windowing and aliasing. The relation is derived between the power spectrum

  9. Quantification of Vortex Generation Due to Non-Equilibrium Electrokinetics at the Micro/Nanochannel Interface: Spectral Analysis

    Directory of Open Access Journals (Sweden)

    Seung Jun Lee

    2016-06-01

    Full Text Available We report on our investigation of a low Reynolds number non-equilibrium electrokinetic flow in a micro/nanochannel platform. Non-equilibrium electrokinetic phenomena include so-called concentration polarization in a moderate electric field and vortex formation in a high electric field. We conducted a spectral analysis of non-equilibrium electrokinetic vortices at a micro/nanochannel interface. We found that periodic vortices are formed while the frequency varies with the applied voltages and solution concentrations. At a frequency as high as 60 Hz, vortex generation was obtained with the strongest electric field and the lowest concentration. The power spectra show increasing frequency with increasing voltage or decreasing concentration. We expect that our spectral analysis results will be useful for micromixer developers in the micromachine research field.

  10. Non-equilibrium quantum heat machines

    Science.gov (United States)

    Alicki, Robert; Gelbwaser-Klimovsky, David

    2015-11-01

    Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.

  11. Magnetic polarons in a nonequilibrium polariton condensate

    Science.gov (United States)

    Mietki, Paweł; Matuszewski, Michał

    2017-09-01

    We consider a condensate of exciton polaritons in a diluted magnetic semiconductor microcavity. Such a system may exhibit magnetic self-trapping in the case of sufficiently strong coupling between polaritons and magnetic ions embedded in the semiconductor. We investigate the effect of the nonequilibrium nature of exciton polaritons on the physics of the resulting self-trapped magnetic polarons. We find that multiple polarons can exist at the same time, and we derive a critical condition for self-trapping that is different from the one predicted previously in the equilibrium case. Using the Bogoliubov-de Gennes approximation, we calculate the excitation spectrum and provide a physical explanation in terms of the effective magnetic attraction between polaritons, mediated by the ion subsystem.

  12. Gravity and Nonequilibrium Thermodynamics of Classical Matter

    CERN Document Server

    Hu, B L

    2010-01-01

    Renewed interest in deriving gravity (more precisely, the Einstein equations) from thermodynamics considerations [1, 2] is stirred up by a recent proposal that 'gravity is an entropic force' [3] (see also [4]). Even though I find the arguments justifying such a claim in this latest proposal rather ad hoc and simplistic compared to the original one I would unreservedly support the call to explore deeper the relation between gravity and thermodynamics, this having the same spirit as my long-held view that general relativity is the hydrodynamic limit [5, 6] of some underlying theories for the microscopic structure of spacetime - all these proposals, together with that of [7, 8], attest to the emergent nature of gravity [9]. In this first paper of two we set the modest goal of studying the nonequilibrium thermodynamics of classical matter only, bringing afore some interesting prior results, without invoking any quantum considerations such as Bekenstein-Hawking entropy, holography or Unruh effect. This is for the ...

  13. Nonequilibrium Chromosome Looping via Molecular Slip Links

    Science.gov (United States)

    Brackley, C. A.; Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.

    2017-09-01

    We propose a model for the formation of chromatin loops based on the diffusive sliding of molecular slip links. These mimic the behavior of molecules like cohesin, which, along with the CTCF protein, stabilize loops which contribute to organizing the genome. By combining 3D Brownian dynamics simulations and 1D exactly solvable nonequilibrium models, we show that diffusive sliding is sufficient to account for the strong bias in favor of convergent CTCF-mediated chromosome loops observed experimentally. We also find that the diffusive motion of multiple slip links along chromatin is rectified by an intriguing ratchet effect that arises if slip links bind to the chromatin at a preferred "loading site." This emergent collective behavior favors the extrusion of loops which are much larger than the ones formed by single slip links.

  14. Maximum caliber inference of nonequilibrium processes

    Science.gov (United States)

    Otten, Moritz; Stock, Gerhard

    2010-07-01

    Thirty years ago, Jaynes suggested a general theoretical approach to nonequilibrium statistical mechanics, called maximum caliber (MaxCal) [Annu. Rev. Phys. Chem. 31, 579 (1980)]. MaxCal is a variational principle for dynamics in the same spirit that maximum entropy is a variational principle for equilibrium statistical mechanics. Motivated by the success of maximum entropy inference methods for equilibrium problems, in this work the MaxCal formulation is applied to the inference of nonequilibrium processes. That is, given some time-dependent observables of a dynamical process, one constructs a model that reproduces these input data and moreover, predicts the underlying dynamics of the system. For example, the observables could be some time-resolved measurements of the folding of a protein, which are described by a few-state model of the free energy landscape of the system. MaxCal then calculates the probabilities of an ensemble of trajectories such that on average the data are reproduced. From this probability distribution, any dynamical quantity of the system can be calculated, including population probabilities, fluxes, or waiting time distributions. After briefly reviewing the formalism, the practical numerical implementation of MaxCal in the case of an inference problem is discussed. Adopting various few-state models of increasing complexity, it is demonstrated that the MaxCal principle indeed works as a practical method of inference: The scheme is fairly robust and yields correct results as long as the input data are sufficient. As the method is unbiased and general, it can deal with any kind of time dependency such as oscillatory transients and multitime decays.

  15. Fourier Transform Methods. Chapter 4

    Science.gov (United States)

    Kaplan, Simon G.; Quijada, Manuel A.

    2015-01-01

    This chapter describes the use of Fourier transform spectrometers (FTS) for accurate spectrophotometry over a wide spectral range. After a brief exposition of the basic concepts of FTS operation, we discuss instrument designs and their advantages and disadvantages relative to dispersive spectrometers. We then examine how common sources of error in spectrophotometry manifest themselves when using an FTS and ways to reduce the magnitude of these errors. Examples are given of applications to both basic and derived spectrophotometric quantities. Finally, we give recommendations for choosing the right instrument for a specific application, and how to ensure the accuracy of the measurement results..

  16. An approximate local thermodynamic nonequilibrium radiation model for air

    Science.gov (United States)

    Gally, Thomas A.; Carlson, Leland A.

    1992-01-01

    A radiatively coupled viscous shock layer analysis program which includes chemical and thermal nonequilibrium is used to calculate stagnation point flow profiles for typical aeroassisted orbital transfer vehicle conditions. Two methods of predicting local thermodynamic nonequilibrium radiation effects are used as a first and second order approximation to this phenomena. Tabulated results for both nitrogen and air freestreams are given with temperature, species, and radiation profiles for some air conditions. Two body solution results are shown for 45 and 60 degree hyperboloid bodies at 12 km/sec and 80 km altitude. The presented results constitute an advancement in the engineering modeling of radiating nonequilibrium reentry flows.

  17. Nonequilibrium fluctuation relations in a quantum coherent conductor.

    Science.gov (United States)

    Nakamura, Shuji; Yamauchi, Yoshiaki; Hashisaka, Masayuki; Chida, Kensaku; Kobayashi, Kensuke; Ono, Teruo; Leturcq, Renaud; Ensslin, Klaus; Saito, Keiji; Utsumi, Yasuhiro; Gossard, Arthur C

    2010-02-26

    We experimentally demonstrate the validity of nonequilibrium fluctuation relations by using a quantum coherent conductor. In equilibrium the fluctuation-dissipation relation leads to the correlation between current and current noise at the conductor, namely, the Johnson-Nyquist relation. When the conductor is voltage biased so that the nonlinear regime is entered, the fluctuation theorem has predicted similar nonequilibrium fluctuation relations, which hold true even when the Onsager-Casmir relations are broken in magnetic fields. Our experiments qualitatively validate the predictions as the first evidence of this theorem in the nonequilibrium quantum regime.

  18. Non-Equilibrium Steady States of the XY Chain

    CERN Document Server

    Aschbacher, W H

    2002-01-01

    We study the non-equilibrium statistical mechanics of the two-sided XY chain. We start from an initial state in which the left and right part of the lattice {x|xM}, are at inverse temperatures beta_L and beta_R. Using a simple scattering theoretic analysis, we construct the unique non-equilibrium steady state (NESS). This state depends on beta_L and beta_R, but not on the choice of the decoupling parameter M. We prove that in the non-equilibrium case, beta_L \

  19. Adaptive denoising method for Fourier ptychographic microscopy

    Science.gov (United States)

    Fan, Yao; Sun, Jiasong; Chen, Qian; Wang, Mingqun; Zuo, Chao

    2017-12-01

    Fourier ptychographic microscopy (FPM) is a recently developed wide-field and high-resolution (HR) imaging technique, reconstructing HR spectrum from a series of low-resolution (LR) images at different illumination angles. Although many significant progresses have been made in FPM in the past few years, imaging noise is still an inevitable problem, which could seriously distort the results recovered using the conventional Fourier ptychography approach without image preprocessing. Generally, before FPM reconstruction, a thresholding denoising method is usually employed to eliminate the noise. However, conventional thresholding denoising algorithms cannot differentiate useful signals from imaging noise effectively, thus these algorithms usually eliminate signals and noise simultaneously. Here we propose an adaptive denoising method for FPM, which takes advantage of the information redundancy in FPM to separate signal from noise during the recovery process without any pre-knowledge about the noise statistics. Simulation and experimental results are presented to evaluate the performance of the proposed method. It is demonstrated that this method can both improve the accuracy and robustness of FPM and relax the imaging performance requirement for implementing high-quality FPM reconstruction.

  20. Fourier Spectroscopy: A Bayesian Way

    Directory of Open Access Journals (Sweden)

    Stefan Schmuck

    2017-01-01

    Full Text Available The concepts of standard analysis techniques applied in the field of Fourier spectroscopy treat fundamental aspects insufficiently. For example, the spectra to be inferred are influenced by the noise contribution to the interferometric data, by nonprobed spatial domains which are linked to Fourier coefficients above a certain order, by the spectral limits which are in general not given by the Nyquist assumptions, and by additional parameters of the problem at hand like the zero-path difference. To consider these fundamentals, a probabilistic approach based on Bayes’ theorem is introduced which exploits multivariate normal distributions. For the example application, we model the spectra by the Gaussian process of a Brownian bridge stated by a prior covariance. The spectra themselves are represented by a number of parameters which map linearly to the data domain. The posterior for these linear parameters is analytically obtained, and the marginalisation over these parameters is trivial. This allows the straightforward investigation of the posterior for the involved nonlinear parameters, like the zero-path difference location and the spectral limits, and hyperparameters, like the scaling of the Gaussian process. With respect to the linear problem, this can be interpreted as an implementation of Ockham’s razor principle.

  1. Evaluation of a method for nitrotyrosine site identification and relative quantitation using a stable isotope-labeled nitrated spike-in standard and high resolution fourier transform MS and MS/MS analysis.

    Science.gov (United States)

    Seeley, Kent W; Fertig, Alison R; Dufresne, Craig P; Pinho, Joao P C; Stevens, Stanley M

    2014-04-14

    The overproduction of reactive oxygen and nitrogen species (ROS and RNS) can have deleterious effects in the cell, including structural and possible activity-altering modifications to proteins. Peroxynitrite is one such RNS that can result in a specific protein modification, nitration of tyrosine residues to form nitrotyrosine, and to date, the identification of nitrotyrosine sites in proteins continues to be a major analytical challenge. We have developed a method by which 15N-labeled nitrotyrosine groups are generated on peptide or protein standards using stable isotope-labeled peroxynitrite (O15NOO-), and the resulting standard is mixed with representative samples in which nitrotyrosine formation is to be measured by mass spectrometry (MS). Nitropeptide MS/MS spectra are filtered using high mass accuracy Fourier transform MS (FTMS) detection of the nitrotyrosine immonium ion. Given that the nitropeptide pair is co-isolated for MS/MS fragmentation, the nitrotyrosine immonium ions (at m/z=181 or 182) can be used for relative quantitation with negligible isotopic interference at a mass resolution of greater than 50,000 (FWHM, full width at half-maximum). Furthermore, the standard potentially allows for the increased signal of nitrotyrosine-containing peptides, thus facilitating selection for MS/MS in a data-dependent mode of acquisition. We have evaluated the methodology in terms of nitrotyrosine site identification and relative quantitation using nitrated peptide and protein standards.

  2. High-sensitivity matrix-assisted laser desorption/ionization Fourier transform mass spectrometry analyses of small carbohydrates and amino acids using oxidized carbon nanotubes prepared by chemical vapor deposition as matrix.

    Science.gov (United States)

    Wang, Cui-hong; Li, Jian; Yao, Sheng-jun; Guo, Yin-long; Xia, Xing-hua

    2007-12-05

    In matrix-assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry (FTMS) analyses of small oligosaccharides and amino acids, high sensitivities for oligosaccharides (10 fmol) were obtained by introducing oxidized carbon nanotubes (CNTs) with short and open-end structure as valuable matrix. The CNTs were deposited in porous anodic alumina (PAA) templates by chemical vapor deposition. Transmission electron microscopy (TEM) images show that those CNTs include low levels of amorphous carbon. Thus, the background interference signals generally caused by amorphous carbon powder in CNTs can be reduced effectively. Experiments also confirmed that the FTMS signal intensity of CNTs prepared in PAA template is much lower than that of commercial multi-wall carbon nanotubes (MCNTs). Moreover, the purified process for CNTs with mixed acid (H2SO4 and HNO3) also contributed to the minimization of background. Intense signals corresponding to alkali cation adduct of neutral carbohydrates and amino acids have been acquired. In addition, reliable quantitative analyses for urine and corn root were also achieved successfully. The present work will open a new way to the application of oxidized CNTs as an effective matrix in MALDI MS research.

  3. Nonequilibrium coexistence in a competition model with nutrient storage

    NARCIS (Netherlands)

    Revilla Rimbach, T.A.; Weissing, F.J.

    Resource competition theory predicts that, in equilibrium, the number of coexisting species cannot exceed the number of limiting resources. In some competition models, however, competitive interactions may result in nonequilibrium dynamics, allowing the coexistence of many species on few resources.

  4. Nonequilibrium electron transport through quantum dots in the Kondo regime

    DEFF Research Database (Denmark)

    Wölfle, Peter; Paaske, Jens; Rosch, Achim

    2005-01-01

    Electron transport at large bias voltage through quantum dots in the Kondo regime is described within the perturbative renormalization group extended to nonequilibrium. The conductance, local magnetization, dynamical spin susceptibility and local spectral function are calculated. We show how...

  5. Linking Equilibrium and Nonequilibrium Dynamics in Glass-Forming Systems

    DEFF Research Database (Denmark)

    Mauro, John C.; Guo, Xiaoju; Smedskjær, Morten Mattrup

    Understanding nonequilibrium glassy dynamics is of great scientific and technological importance. However, prediction of the temperature, thermal history, and composition dependence of nonequilibrium viscosity is challenging due to the noncrystalline and nonergodic nature of the glassy state. Here......, we show that the nonequilibrium glassy dynamics are intimately connected with the equilibrium liquid dynamics. This is accomplished by deriving a new functional form for the thermal history dependence of nonequilibrium viscosity, which is validated against experimental measurements of industrial...... silicate glasses and computed viscosities for selenium over a wide range of conditions. Since the temperature and composition dependence of liquid viscosity can be predicted using temperature-dependent constraint theory, our work also opens the possibility to improve understanding of the physics...

  6. Foundations of atmospheric pressure non-equilibrium plasmas

    Science.gov (United States)

    Bruggeman, Peter J.; Iza, Felipe; Brandenburg, Ronny

    2017-12-01

    Non-equilibrium plasmas have been intensively studied over the past century in the context of material processing, environmental remediation, ozone generation, excimer lamps and plasma display panels. Research on atmospheric pressure non-equilibrium plasmas intensified over the last two decades leading to a large variety of plasma sources that have been developed for an extended application range including chemical conversion, medicine, chemical analysis and disinfection. The fundamental understanding of these discharges is emerging but there remain a lot of unexplained phenomena in these intrinsically complex plasmas. The properties of non-equilibrium plasmas at atmospheric pressure span over a huge range of electron densities as well as heavy particle and electron temperatures. This paper provides an overview of the key underlying processes that are important for the generation and stabilization of atmospheric pressure non-equilibrium plasmas. The unique physical and chemical properties of theses discharges are also summarized.

  7. Fractality in nonequilibrium steady states of quasiperiodic systems

    Science.gov (United States)

    Varma, Vipin Kerala; de Mulatier, Clélia; Žnidarič, Marko

    2017-09-01

    We investigate the nonequilibrium response of quasiperiodic systems to boundary driving. In particular, we focus on the Aubry-André-Harper model at its metal-insulator transition and the diagonal Fibonacci model. We find that opening the system at the boundaries provides a viable experimental technique to probe its underlying fractality, which is reflected in the fractal spatial dependence of simple observables (such as magnetization) in the nonequilibrium steady state. We also find that the dynamics in the nonequilibrium steady state depends on the length of the chain chosen: generic length chains harbour qualitatively slower transport (different scaling exponent) than Fibonacci length chains, which is in turn slower than in the closed system. We conjecture that such fractal nonequilibrium steady states should arise in generic driven critical systems that have fractal properties.

  8. Non-Equilibrium Thermodynamics of Self-Replicating Protocells

    DEFF Research Database (Denmark)

    Fellermann, Harold; Corominas-Murtra, Bernat; Hansen, Per Lyngs

    2017-01-01

    We provide a non-equilibrium thermodynamic description of the life-cycle of a droplet based, chemically feasible, system of protocells. By coupling the protocells metabolic kinetics with its thermodynamics, we demonstrate how the system can be driven out of equilibrium to ensure protocell growth...... and replication. This coupling allows us to derive the equations of evolution and to rigorously demonstrate how growth and replication life-cycle can be understood as a non-equilibrium thermodynamic cycle. The process does not appeal to genetic information or inheritance, and is based only on non......-equilibrium physics considerations. Our non-equilibrium thermodynamic description of simple, yet realistic, processes of protocell growth and replication, represents an advance in our physical understanding of a central biological phenomenon both in connection to the origin of life and for modern biology....

  9. PREFACE: International Symposium on Non-Equilibrium Soft Matter 2010 International Symposium on Non-Equilibrium Soft Matter 2010

    Science.gov (United States)

    Kawakatsu, T.; Matsuyama, A.; Ohta, T.; Tanaka, H.; Tanaka, S.

    2011-07-01

    , Culture, Sports, Science and Technology (MEXT) of Japan. We thank those who contributed to this symposium as well as members of the 'Soft Matter Physics' project for their valuable discussions and collaborations. Non-equilibrium soft matter contents Insights on raft behavior from minimal phenomenological models G Garbès Putzel and M Schick Dynamical membrane curvature instability controlled by intermonolayer friction Anne-Florence Bitbol, Jean-Baptiste Fournier, Miglena I Angelova and Nicolas Puff Numerical investigations of the dynamics of two-component vesicles Takashi Taniguchi, Miho Yanagisawa and Masayuki Imai Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique Y Sakuma, N Urakami, T Taniguchi and M Imai Hydration, phase separation and nonlinear rheology of temperature-sensitive water-soluble polymers Fumihiko Tanaka, Tsuyoshi Koga, Isamu Kaneda and Françoise M Winnik Morphology and rheology of an immiscible polymer blend subjected to a step electric field under shear flow H Orihara, Y Nishimoto, K Aida, Y H Na, T Nagaya and S Ujiie Surfactant-induced friction reduction for hydrogels in the boundary lubrication regime Kosuke Kamada, Hidemitsu Furukawa, Takayuki Kurokawa, Tomohiro Tada, Taiki Tominaga, Yukihiro Nakano and Jian Ping Gong Fabrication and structural analysis of polyrotaxane fibers and films Yasuhiro Sakai, Kentaro Ueda, Naoya Katsuyama, Koji Shimizu, Shunya Sato, Jun Kuroiwa, Jun Araki, Akira Teramoto, Koji Abe, Hideaki Yokoyama and Kohzo Ito Micellization kinetics of diblock copolymers in a homopolymer matrix: a self-consistent field study Raghuram Thiagarajan and David C Morse Hierarchical self-assembly of two-length-scale multiblock copolymers Gerrit ten Brinke, Katja Loos, Ivana Vukovic and Gerrit Gobius du Sart Kaleidoscopic morphologies from ABC star-shaped terpolymers Yushu Matsushita, Kenichi Hayashida, Tomonari Dotera and Atsushi Takano Direct and inverted nematic

  10. Lipid profiles of adipose and muscle tissues in mouse models of juvenile onset of obesity without high fat diet induction: a Fourier transform infrared (FT-IR) spectroscopic study.

    Science.gov (United States)

    Sen, Ilke; Bozkurt, Ozlem; Aras, Ebru; Heise, Sebastian; Brockmann, Gudrun Anni; Severcan, Feride

    2015-06-01

    The current study aims to determine lipid profiles in terms of the content and structure of skeletal muscle and adipose tissues to better understand the characteristics of juvenile-onset spontaneous obesity without high fat diet induction. For the purposes of this study, muscle (longissimus, quadriceps) and adipose (inguinal, gonadal) tissues of 10-week-old male DBA/2J and Berlin fat mouse inbred (BFMI) lines (BFMI856, BFMI860, BFMI861) fed with a standard breeding diet were used. Biomolecular structure and composition was determined using attenuated total reflection Fourier transform (ATR FT-IR) spectroscopy, and muscle triglyceride content was further quantified using high-performance liquid chromatography (HPLC) coupled with an evaporative light scattering detector (ELSD). The results revealed a loss of unsaturation in BFMI860 and BFMI861 lines in both muscles and inguinal adipose tissue, together with a decrease in the hydrocarbon chain length of lipids, especially in the BFMI860 line in muscles, suggesting an increased lipid peroxidation. There was an increase in saturated lipid and triglyceride content in all tissues of BFMI lines, more profoundly in longissimus muscle, where the increased triglyceride content was quantitatively confirmed by HPLC-ELSD. Moreover, an increase in the metabolic turnover of carbohydrates in muscles of the BFMI860 line was observed. The results demonstrated that subcutaneous (inguinal) fat also displayed considerable obesity-induced alterations. Taken together, the results revealed differences in lipid structure and content of BFMI lines, which may originate from different insulin sensitivity levels of the lines, making them promising animal models for spontaneous obesity. The results will contribute to the understanding of the generation of insulin resistance in obesity without high fat diet induction.

  11. Power conversion efficiency of non-equilibrium light absorption

    Directory of Open Access Journals (Sweden)

    I. Santamaría-Holek

    2017-04-01

    Full Text Available We deduce a novel expression for the non-equilibrium photochemical potential and the power conversion efficiency of non-equilibrium light absorption by a thermostated material. Application of our results for the case of electron migration from valence to conduction bands in photovoltaic cells allows us to accurately interpolate experimental results for the maximal efficiencies of Ge-, Si-, GaAs-based cells and the like.

  12. Iterative wave-front reconstruction in the Fourier domain.

    Science.gov (United States)

    Bond, Charlotte Z; Correia, Carlos M; Sauvage, Jean-François; Neichel, Benoit; Fusco, Thierry

    2017-05-15

    The use of Fourier methods in wave-front reconstruction can significantly reduce the computation time for large telescopes with a high number of degrees of freedom. However, Fourier algorithms for discrete data require a rectangular data set which conform to specific boundary requirements, whereas wave-front sensor data is typically defined over a circular domain (the telescope pupil). Here we present an iterative Gerchberg routine modified for the purposes of discrete wave-front reconstruction which adapts the measurement data (wave-front sensor slopes) for Fourier analysis, fulfilling the requirements of the fast Fourier transform (FFT) and providing accurate reconstruction. The routine is used in the adaptation step only and can be coupled to any other Wiener-like or least-squares method. We compare simulations using this method with previous Fourier methods and show an increase in performance in terms of Strehl ratio and a reduction in noise propagation for a 40×40 SPHERE-like adaptive optics system. For closed loop operation with minimal iterations the Gerchberg method provides an improvement in Strehl, from 95.4% to 96.9% in K-band. This corresponds to ~ 40 nm improvement in rms, and avoids the high spatial frequency errors present in other methods, providing an increase in contrast towards the edge of the correctable band.

  13. Fourier phase microscopy with white light.

    Science.gov (United States)

    Bhaduri, Basanta; Tangella, Krishnarao; Popescu, Gabriel

    2013-01-01

    Laser-based Fourier phase microscopy (FPM) works on the principle of decomposition of an image field in two spatial components that can be controllably shifted in phase with respect to each other. However, due to the coherent illumination, the contrast in phase images is degraded by speckles. In this paper we present FPM with spatially coherent white light (wFPM), which offers high spatial phase sensitivity due to the low temporal coherence and high temporal phase stability due to common path geometry. Further, by using a fast spatial light modulator (SLM) and a fast scientific-grade complementary metal oxide semiconductor (sCMOS) camera, we report imaging at a maximum rate of 12.5 quantitative phase frames per second with 5.5 mega pixels image size. We illustrate the utility of wFPM as a contrast enhancement as well as dynamic phase measurement method by imaging section of benign colonic glands and red blood cell membrane fluctuation.

  14. Complex Dynamics in Nonequilibrium Economics and Chemistry

    Science.gov (United States)

    Wen, Kehong

    Complex dynamics provides a new approach in dealing with economic complexity. We study interactively the empirical and theoretical aspects of business cycles. The way of exploring complexity is similar to that in the study of an oscillatory chemical system (BZ system)--a model for modeling complex behavior. We contribute in simulating qualitatively the complex periodic patterns observed from the controlled BZ experiments to narrow the gap between modeling and experiment. The gap between theory and reality is much wider in economics, which involves studies of human expectations and decisions, the essential difference from natural sciences. Our empirical and theoretical studies make substantial progress in closing this gap. With the help from the new development in nonequilibrium physics, i.e., the complex spectral theory, we advance our technique in detecting characteristic time scales from empirical economic data. We obtain correlation resonances, which give oscillating modes with decays for correlation decomposition, from different time series including S&P 500, M2, crude oil spot prices, and GNP. The time scales found are strikingly compatible with business experiences and other studies in business cycles. They reveal the non-Markovian nature of coherent markets. The resonances enhance the evidence of economic chaos obtained by using other tests. The evolving multi-humped distributions produced by the moving-time -window technique reveal the nonequilibrium nature of economic behavior. They reproduce the American economic history of booms and busts. The studies seem to provide a way out of the debate on chaos versus noise and unify the cyclical and stochastic approaches in explaining business fluctuations. Based on these findings and new expectation formulation, we construct a business cycle model which gives qualitatively compatible patterns to those found empirically. The soft-bouncing oscillator model provides a better alternative than the harmonic oscillator

  15. Achieving Radiation Tolerance through Non-Equilibrium Grain Boundary Structures.

    Science.gov (United States)

    Vetterick, Gregory A; Gruber, Jacob; Suri, Pranav K; Baldwin, Jon K; Kirk, Marquis A; Baldo, Pete; Wang, Yong Q; Misra, Amit; Tucker, Garritt J; Taheri, Mitra L

    2017-09-25

    Many methods used to produce nanocrystalline (NC) materials leave behind non-equilibrium grain boundaries (GBs) containing excess free volume and higher energy than their equilibrium counterparts with identical 5 degrees of freedom. Since non-equilibrium GBs have increased amounts of both strain and free volume, these boundaries may act as more efficient sinks for the excess interstitials and vacancies produced in a material under irradiation as compared to equilibrium GBs. The relative sink strengths of equilibrium and non-equilibrium GBs were explored by comparing the behavior of annealed (equilibrium) and as-deposited (non-equilibrium) NC iron films on irradiation. These results were coupled with atomistic simulations to better reveal the underlying processes occurring on timescales too short to capture using in situ TEM. After irradiation, NC iron with non-equilibrium GBs contains both a smaller number density of defect clusters and a smaller average defect cluster size. Simulations showed that excess free volume contribute to a decreased survival rate of point defects in cascades occurring adjacent to the GB and that these boundaries undergo less dramatic changes in structure upon irradiation. These results suggest that non-equilibrium GBs act as more efficient sinks for defects and could be utilized to create more radiation tolerant materials in future.

  16. Mesoscopic non-equilibrium thermodynamics of non-isothermal reaction-diffusion.

    Science.gov (United States)

    Bedeaux, D; Pagonabarraga, I; Ortiz de Zárate, J M; Sengers, J V; Kjelstrup, S

    2010-10-21

    We show how the law of mass action can be derived from a thermodynamic basis, in the presence of temperature gradients, chemical potential gradients and hydrodynamic flow. The solution gives the law of mass action for the forward and the reverse contributions to the net chemical reaction. In addition we derive the fluctuation-dissipation theorem for the fluctuating contributions to the reaction rate, heat flux and mass fluxes. All these results arise without any other assumptions than those which are common in mesoscopic non-equilibrium thermodynamics; namely quasi-stationary transport across a high activation energy barrier, and local equilibrium along the reaction coordinate. Arrhenius-type behaviour of the kinetic coefficients is recovered. The thermal conductivity, Soret coefficient and diffusivity are significantly influenced by the presence of a chemical reaction. We thus demonstrate how chemical reactions can be fully reconciled with non-equilibrium thermodynamics.

  17. Nonequilibrium phase transition in an exactly solvable driven Ising model with friction.

    Science.gov (United States)

    Hucht, Alfred

    2009-12-01

    A driven Ising model with friction due to magnetic correlations was proposed by Kadau [Phys. Rev. Lett. 101, 137205 (2008)]. The nonequilibrium phase transition present in this system is investigated in detail using analytical methods as well as Monte Carlo simulations. In the limit of high driving velocities v the model shows mean-field behavior due to dimensional reduction and can be solved exactly for various geometries. The simulations are performed with three different single spin-flip rates: the common Metropolis and Glauber rates as well as a multiplicative rate. Due to the nonequilibrium nature of the model all rates lead to different critical temperatures at v>0, while the exact solution matches the multiplicative rate. Finally, the crossover from Ising to mean-field behavior as function of velocity and system size is analyzed in one and two dimensions.

  18. Wall catalytic recombination and boundary conditions in nonequilibrium hypersonic flows - With applications

    Science.gov (United States)

    Scott, Carl D.

    1992-01-01

    The meaning of catalysis and its relation to aerodynamic heating in nonequilibrium hypersonic flows are discussed. The species equations are described and boundary conditions for them are derived for a multicomponent gas and for a binary gas. Slip effects are included for application of continuum methods to low-density flows. Measurement techniques for determining catalytic wall recombination rates are discussed. Among them are experiments carried out in arc jets as well as flow reactors. Diagnostic methods for determining the atom or molecule concentrations in the flow are included. Results are given for a number of materials of interest to the aerospace community, including glassy coatings such as the RCG coating of the Space Shuttle and for high temperature refractory metals such as coated niobium. Methods of calculating the heat flux to space vehicles in nonequilibrium flows are described. These methods are applied to the Space Shuttle, the planned Aeroassist Flight Experiment, and a hypersonic slender vehicle such as a transatmospheric vehicle.

  19. Nonequilibrium gas-liquid transition in the driven-dissipative photonic lattice

    Science.gov (United States)

    Biondi, Matteo; Blatter, Gianni; Türeci, Hakan E.; Schmidt, Sebastian

    2017-10-01

    We study the nonequilibrium steady state of the driven-dissipative Bose-Hubbard model with Kerr nonlinearity. Employing a mean-field decoupling for the intercavity hopping J , we find that the steep crossover between low and high photon-density states inherited from the single cavity transforms into a gas-liquid bistability at large cavity-coupling J . We formulate a van der Waals-like gas-liquid phenomenology for this nonequilibrium setting and determine the relevant phase diagrams, including a new type of diagram where a lobe-shaped boundary separates smooth crossovers from sharp, hysteretic transitions. Calculating quantum trajectories for a one-dimensional system, we provide insights into the microscopic origin of the bistability.

  20. Numerical Simulation of Non-Equilibrium Two-Phase Wet Steam Flow through an Asymmetric Nozzle

    Directory of Open Access Journals (Sweden)

    Miah Md Ashraful Alam

    2017-11-01

    Full Text Available The present study reported of the numerical investigation of a high-speed wet steam flow through an asymmetric nozzle. The spontaneous non-equilibrium homogeneous condensation of wet steam was numerically modeled based on the classical nucleation theory and droplet growth rate equation combined with the field conservations within the computational fluid dynamics (CFD code of ANSYS Fluent 13.0. The equations describing droplet formations and interphase change were solved sequentially after solving the main flow conservation equations. The calculations were carried out assuming the flow two-dimensional, compressible, turbulent, and viscous. The SST k-ω model was used for modeling the turbulence within an unstructured mesh solver. The validation of numerical model was accomplished, and the results showed a good agreement between the numerical simulation and experimental data. The effect of spontaneous non-equilibrium condensation on the jet and shock structures was revealed, and the condensation shown a great influence on the jet structure.

  1. A parallel Fast Fourier transform

    CERN Document Server

    Morante, S; Salina, G

    1999-01-01

    In this paper we discuss the general problem of implementing the multidimensional Fast Fourier Transform algorithm on parallel computers. We show that, on a machine with P processors and fully parallel node communications, the optimal asymptotic scaling behavior of the total computational time with the number of data points, N, given in d dimensions by the formula aN/Plog(N/P)+bN/P/sup (d-1)/d/, can actually be achieved on realistic platforms. As a concrete realization of our strategy, we have produced codes efficiently running on machines of the APE family and on Cray T3E. On the former for asymptotic values of N our codes attain the above optimal result. (16 refs).

  2. Applications of Fourier transforms to generalized functions

    CERN Document Server

    Rahman, M

    2011-01-01

    This book explains how Fourier transforms can be applied to generalized functions. The generalized function is one of the important branches of mathematics and is applicable in many practical fields. Its applications to the theory of distribution and signal processing are especially important. The Fourier transform is a mathematical procedure that can be thought of as transforming a function from its time domain to the frequency domain.The book contains six chapters and three appendices. Chapter 1 deals with preliminary remarks on Fourier series from a general point of view and also contains an introduction to the first generalized function. Chapter 2 is concerned with the generalized functions and their Fourier transforms. Chapter 3 contains the Fourier transforms of particular generalized functions. The author has stated and proved 18 formulas dealing with the Fourier transforms of generalized functions, and demonstrated some important problems of practical interest. Chapter 4 deals with the asymptotic esti...

  3. Validation of vibration-dissociation coupling models in hypersonic non-equilibrium separated flows

    Science.gov (United States)

    Shoev, G.; Oblapenko, G.; Kunova, O.; Mekhonoshina, M.; Kustova, E.

    2018-03-01

    The validation of recently developed models of vibration-dissociation coupling is discussed in application to numerical solutions of the Navier-Stokes equations in a two-temperature approximation for a binary N2/N flow. Vibrational-translational relaxation rates are computed using the Landau-Teller formula generalized for strongly non-equilibrium flows obtained in the framework of the Chapman-Enskog method. Dissociation rates are calculated using the modified Treanor-Marrone model taking into account the dependence of the model parameter on the vibrational state. The solutions are compared to those obtained using traditional Landau-Teller and Treanor-Marrone models, and it is shown that for high-enthalpy flows, the traditional and recently developed models can give significantly different results. The computed heat flux and pressure on the surface of a double cone are in a good agreement with experimental data available in the literature on low-enthalpy flow with strong thermal non-equilibrium. The computed heat flux on a double wedge qualitatively agrees with available data for high-enthalpy non-equilibrium flows. Different contributions to the heat flux calculated using rigorous kinetic theory methods are evaluated. Quantitative discrepancy of numerical and experimental data is discussed.

  4. Handbook of Fourier analysis & its applications

    CERN Document Server

    Marks, Robert J

    2009-01-01

    Fourier analysis has many scientific applications - in physics, number theory, combinatorics, signal processing, probability theory, statistics, option pricing, cryptography, acoustics, oceanography, optics and diffraction, geometry, and other areas. In signal processing and related fields, Fourier analysis is typically thought of as decomposing a signal into its component frequencies and their amplitudes. This practical, applications-based professional handbook comprehensively covers the theory and applications of Fourier Analysis, spanning topics from engineering mathematics, signal process

  5. Nonequilibrium landscape theory of neural networks

    Science.gov (United States)

    Yan, Han; Zhao, Lei; Hu, Liang; Wang, Xidi; Wang, Erkang; Wang, Jin

    2013-01-01

    The brain map project aims to map out the neuron connections of the human brain. Even with all of the wirings mapped out, the global and physical understandings of the function and behavior are still challenging. Hopfield quantified the learning and memory process of symmetrically connected neural networks globally through equilibrium energy. The energy basins of attractions represent memories, and the memory retrieval dynamics is determined by the energy gradient. However, the realistic neural networks are asymmetrically connected, and oscillations cannot emerge from symmetric neural networks. Here, we developed a nonequilibrium landscape–flux theory for realistic asymmetrically connected neural networks. We uncovered the underlying potential landscape and the associated Lyapunov function for quantifying the global stability and function. We found the dynamics and oscillations in human brains responsible for cognitive processes and physiological rhythm regulations are determined not only by the landscape gradient but also by the flux. We found that the flux is closely related to the degrees of the asymmetric connections in neural networks and is the origin of the neural oscillations. The neural oscillation landscape shows a closed-ring attractor topology. The landscape gradient attracts the network down to the ring. The flux is responsible for coherent oscillations on the ring. We suggest the flux may provide the driving force for associations among memories. We applied our theory to rapid-eye movement sleep cycle. We identified the key regulation factors for function through global sensitivity analysis of landscape topography against wirings, which are in good agreements with experiments. PMID:24145451

  6. Fluctuations When Driving Between Nonequilibrium Steady States

    Science.gov (United States)

    Riechers, Paul M.; Crutchfield, James P.

    2017-08-01

    Maintained by environmental fluxes, biological systems are thermodynamic processes that operate far from equilibrium without detailed-balanced dynamics. Yet, they often exhibit well defined nonequilibrium steady states (NESSs). More importantly, critical thermodynamic functionality arises directly from transitions among their NESSs, driven by environmental switching. Here, we identify the constraints on excess heat and dissipated work necessary to control a system that is kept far from equilibrium by background, uncontrolled "housekeeping" forces. We do this by extending the Crooks fluctuation theorem to transitions among NESSs, without invoking an unphysical dual dynamics. This and corresponding integral fluctuation theorems determine how much work must be expended when controlling systems maintained far from equilibrium. This generalizes thermodynamic feedback control theory, showing that Maxwellian Demons can leverage mesoscopic-state information to take advantage of the excess energetics in NESS transitions. We also generalize an approach recently used to determine the work dissipated when driving between functionally relevant configurations of an active energy-consuming complex system. Altogether, these results highlight universal thermodynamic laws that apply to the accessible degrees of freedom within the effective dynamic at any emergent level of hierarchical organization. By way of illustration, we analyze a voltage-gated sodium ion channel whose molecular conformational dynamics play a critical functional role in propagating action potentials in mammalian neuronal membranes.

  7. Fast Fourier single-pixel imaging via binary illumination.

    Science.gov (United States)

    Zhang, Zibang; Wang, Xueying; Zheng, Guoan; Zhong, Jingang

    2017-09-20

    Fourier single-pixel imaging (FSI) employs Fourier basis patterns for encoding spatial information and is capable of reconstructing high-quality two-dimensional and three-dimensional images. Fourier-domain sparsity in natural scenes allows FSI to recover sharp images from undersampled data. The original FSI demonstration, however, requires grayscale Fourier basis patterns for illumination. This requirement imposes a limitation on the imaging speed as digital micro-mirror devices (DMDs) generate grayscale patterns at a low refreshing rate. In this paper, we report a new strategy to increase the speed of FSI by two orders of magnitude. In this strategy, we binarize the Fourier basis patterns based on upsampling and error diffusion dithering. We demonstrate a 20,000 Hz projection rate using a DMD and capture 256-by-256-pixel dynamic scenes at a speed of 10 frames per second. The reported technique substantially accelerates image acquisition speed of FSI. It may find broad imaging applications at wavebands that are not accessible using conventional two-dimensional image sensors.

  8. Fourier ptychographic reconstruction using Wirtinger flow optimization

    CERN Document Server

    Bian, Liheng; Zheng, Guoan; Guo, KaiKai; Chen, Feng; Dai, Qionghai

    2014-01-01

    Recently Fourier Ptychography (FP) has attracted great attention, due to its marked effectiveness in leveraging snapshot numbers for spatial resolution in large field-of-view imaging. To acquire high signal-to-noise-ratio (SNR) images under angularly varying illuminations for subsequent reconstruction, FP requires long exposure time, which largely limits its practical applications. In this paper, based on the recently reported Wirtinger flow algorithm, we propose an iterative optimization framework incorporating phase retrieval and noise relaxation together, to realize FP reconstruction using low SNR images captured under short exposure time. Experiments on both synthetic and real captured data validate the effectiveness of the proposed reconstruction method. Specifically, the proposed technique could save around 80% exposure time to achieve similar retrieval accuracy compared to the conventional FP. Besides, we have released our source code for non-commercial use.

  9. Comparative gas chromatography-mass spectroscopy, Fourier transform infrared spectroscopy, and high-performance liquid chromatography analysis of essential oils extracted using 4 methods from the leaves of Eucalyptus globulus L.

    Directory of Open Access Journals (Sweden)

    Yasmeen Khan

    2016-01-01

    Full Text Available Background: Eucalyptus globulus L. (family, Myrtaceae is one of the world′s most widely planted genera. E. globulus L., commonly referred to as Tasmanian blue gum, is a fast growing, evergreen tree, native to Tasmania and South-East Australia. Apart from its extensive use in pulp industry, it is also produces Oleum Eucalypti (eucalyptus oil that is extracted on commercial scale in many countries such as China, India, South Africa, Portugal, Brazil, and Tasmania, as a raw material in perfumery, cosmetics, food beverage, aromatherapy, and phytotherapy. Materials and Methods: Traditional hydrodistillation (HD, solvent extraction (SE, ultrasonication (US, and supercritical fluid extraction (SFE were conducted for the extraction of essential oil from the leaves of E. globulus. Each oil was evaluated in terms of high-performance liquid chromatography (HPTLC and Fourier transform infrared spectroscopy (FTIR fingerprinting with qualitative and semi-quantitative composition of the isolated essential oil by gas chromatography-mass spectroscopy (GCMS, the extract yield of essential oil was 2.60%, 2.2%, 2.0%, and 3.6% v/w, respectively, for HD, SE, US, and SFE. Results: A total of 53 compounds were identified by GCMS. Comparative analysis indicated that SFE was favorable for extraction of monoterpene hydrocarbon, sesquiterpene hydrocarbon, and oxygenated sesquiterpene hydrocarbon. HD, SE, and US had certain advantages in the extraction of aliphatic saturated hydrocarbons organic acid and esters. Overlay, FTIR spectra of oil samples obtained by four extraction methods were superimposed with each other showing similar components. The maximum separation of compound seen at 254 nm and lesser at 366 nm by HPTLC fingerprinting which again showed superimposed chromatograms. Conclusion: It is concluded that different extraction method may lead to different yields of essential oils where the choice of appropriate method is very important to obtained more desired

  10. Fourier transform infrared spectra applications to chemical systems

    CERN Document Server

    Ferraro, John R

    1978-01-01

    Fourier Transform Infrared Spectroscopy: Applications to Chemical Systems presents the chemical applications of the Fourier transform interferometry (FT-IR).The book contains discussions on the applications of FT-IR in the fields of chromatography FT-IR, polymers and biological macromolecules, emission spectroscopy, matrix isolation, high-pressure interferometry, and far infrared interferometry. The final chapter is devoted to the presentation of the use of FT-IR in solving national technical problems such as air pollution, space exploration, and energy related subjects.Researc

  11. Fourier shape descriptors in fish preliminary results with Prochilodus

    Science.gov (United States)

    Torres, Audalio Rebelo; Silva, Josielma dos Santos; Neta, Raimunda Nonata Fortes Carvalho

    2017-11-01

    In this work, we analyzed fifteen Prochilodus applying Fourier shape descriptors techniques in order to test a method potential to detect and distinguish features like gonadal stage. The technique consists in obtains captured images from the fishes with high resolution, digitized the contours of the fish and obtains Cartesian coordinates of the points in the fish image border. These coordinates of each fish is adjusted to a Fourier discrete polynomial and the variability of each harmonic is obtained and evaluated. The initial results show a promising potential in distinguish fish features.

  12. Fractional Fourier transform of Lorentz-Gauss beams.

    Science.gov (United States)

    Zhou, Guoquan

    2009-02-01

    Lorentz-Gauss beams are introduced to describe certain laser sources that produce highly divergent beams. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz-Gauss beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz-Gauss beam passing through an FRFT system has been derived. By using the derived expression, the properties of a Lorentz-Gauss beam in the FRFT plane are graphically illustrated with numerical examples.

  13. Non-equilibrium plasma experiments at The Pennsylvania State University

    Science.gov (United States)

    Knecht, Sean; Bilen, Sven; Micci, Michael

    2013-10-01

    The authors have recently established the capability at The Pennsylvania State University to generate non-equilibrium plasma in atmospheric-pressure air and liquids such as water and saline. The plasma is generated using a high-voltage pulser (Pacific-Electronics PT-55), which is capable of voltage pulses of 75-ns width, peak voltage >50 kV, with rise-times on the order of nanoseconds. The electrodes are tungsten wires of various diameters (50 μm, 175 μm, 254 μm) insulated with nylon tubing. The spacing of the electrodes is controlled with translating mounts with resolution of tens of microns. Spectroscopy (Ocean Optics Model HR2000) is presently used for line identification only. Current and voltage vs. time will be measured with a 500-MHz bandwidth oscilloscope, a high-voltage probe and a shunt resistor connected to the ground side of the circuit. Research directions presently being pursued include the effects of solution electrical conductivity on plasma production and propellant ignition studies. Data from several types of experiments will be presented.

  14. New phenomena in non-equilibrium quantum physics

    Science.gov (United States)

    Kitagawa, Takuya

    From its beginning in the early 20th century, quantum theory has become progressively more important especially due to its contributions to the development of technologies. Quantum mechanics is crucial for current technology such as semiconductors, and also holds promise for future technologies such as superconductors and quantum computing. Despite of the success of quantum theory, its applications have been mostly limited to equilibrium or static systems due to 1. lack of experimental controllability of non-equilibrium quantum systems 2. lack of theoretical frameworks to understand non-equilibrium dynamics. Consequently, physicists have not yet discovered too many interesting phenomena in non-equilibrium quantum systems from both theoretical and experimental point of view and thus, non-equilibrium quantum physics did not attract too much attentions. The situation has recently changed due to the rapid development of experimental techniques in condensed matter as well as cold atom systems, which now enables a better control of non-equilibrium quantum systems. Motivated by this experimental progress, we constructed theoretical frameworks to study three different non-equilibrium regimes of transient dynamics, steady states and periodically drives. These frameworks provide new perspectives for dynamical quantum process, and help to discover new phenomena in these systems. In this thesis, we describe these frameworks through explicit examples and demonstrate their versatility. Some of these theoretical proposals have been realized in experiments, confirming the applicability of the theories to realistic experimental situations. These studies have led to not only the improved fundamental understanding of non-equilibrium processes in quantum systems, but also suggested entirely different venues for developing quantum technologies.

  15. Electrical pulse measurement, inelastic relaxation, and non-equilibrium transport in a quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, T [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan); Austing, D G [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan); Institute of Microstructural Science M23A, National Research Council of Canada, Ottawa, ON K1A 0R6 (Canada); Tokura, Y [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan); Hirayama, Y [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan); CREST, 4-1-8 Honmachi, Kawaguchi 331-0012 (Japan); Tarucha, S [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan); University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); ERATO Mesoscopic Correlation Project, 3-1 Morinosato-Wakamiya, Atsugi 243-0198 (Japan)

    2003-08-27

    We review electrical pulse experiments carried out to probe inelastic energy relaxation processes and related non-equilibrium transport characteristics of quantum dots (QDs) in the Coulomb blockade (CB) regime. In contrast to the relatively short momentum relaxation time ({approx}10 ns) that can be understood on the basis of acoustic phonon emission, the spin-flip relaxation time is found to be extremely long ({approx}200 {mu}s). The spin relaxation process in our QDs is actually dominated by a cotunnelling process, and thus the intrinsic spin relaxation should have a longer relaxation time. The long relaxation time is discussed in terms of potential applications to spin-based quantum information storage. On the other hand, the extremely long spin relaxation process can induce considerable fluctuation of the spin, charge, and total energy of the QD. The absence of efficient spin relaxation processes can cause highly non-equilibrium transport, which actually 'breaks down' the single-electron tunnelling scheme. The non-equilibrium effects must be considered when electrons and spins are manipulated in the CB regime. (topical review)

  16. The effect of non-equilibrium metal cooling on the interstellar medium

    Science.gov (United States)

    Capelo, Pedro R.; Bovino, Stefano; Lupi, Alessandro; Schleicher, Dominik R. G.; Grassi, Tommaso

    2018-01-01

    By using a novel interface between the modern smoothed particle hydrodynamics code GASOLINE2 and the chemistry package KROME, we follow the hydrodynamical and chemical evolution of an isolated galaxy. In order to assess the relevance of different physical parameters and prescriptions, we constructed a suite of ten simulations, in which we vary the chemical network (primordial and metal species), how metal cooling is modelled (non-equilibrium versus equilibrium; optically thin versus thick approximation), the initial gas metallicity (from ten to hundred per cent solar), and how molecular hydrogen forms on dust. This is the first work in which metal injection from supernovae, turbulent metal diffusion, and a metal network with non-equilibrium metal cooling are self-consistently included in a galaxy simulation. We find that properly modelling the chemical evolution of several metal species and the corresponding non-equilibrium metal cooling has important effects on the thermodynamics of the gas, the chemical abundances, and the appearance of the galaxy: the gas is typically warmer, has a larger molecular gas mass fraction, and has a smoother disc. We also conclude that, at relatively high metallicity, the choice of molecular-hydrogen formation rates on dust is not crucial. Moreover, we confirm that a higher initial metallicity produces a colder gas and a larger fraction of molecular gas, with the low-metallicity simulation best matching the observed molecular Kennicutt-Schmidt relation. Finally, our simulations agree quite well with observations which link star formation rate to metal emission lines.

  17. Fourier ptychographic microscopy at telecommunication wavelengths using a femtosecond laser

    Science.gov (United States)

    Ahmed, Ishtiaque; Alotaibi, Maged; Skinner-Ramos, Sueli; Dominguez, Daniel; Bernussi, Ayrton A.; de Peralta, Luis Grave

    2017-12-01

    We report the implementation of the Fourier Ptychographic Microscopy (FPM) technique, a phase retrieval technique, at telecommunication wavelengths using a low-coherence ultrafast pulsed laser source. High quality images, near speckle-free, were obtained with the proposed approach. We demonstrate that FPM can also be used to image periodic features through a silicon wafer.

  18. An introduction to non-harmonic Fourier series

    CERN Document Server

    Young, Robert M

    2001-01-01

    An Introduction to Non-Harmonic Fourier Series, Revised Edition is an update of a widely known and highly respected classic textbook.Throughout the book, material has also been added on recent developments, including stability theory, the frame radius, and applications to signal analysis and the control of partial differential equations.

  19. Assessment of nonequilibrium free energy methods.

    Science.gov (United States)

    Cossins, Benjamin P; Foucher, Sebastien; Edge, Colin M; Essex, Jonathan W

    2009-04-23

    One of the factors preventing the general application of free energy methods in rational drug design remains the lack of sufficient computational resources. Many nonequilibrium (NE) free energy methods, however, are easily made embarrassingly parallel in comparison to equilibrium methods and may be conveniently run on desktop computers using distributed computing software. In recent years, there has been a proliferation of NE methods, but the general applicability of these approaches has not been determined. In this study, a subset including only those NE methods which are easily parallelised were considered for examination, with a view to their application to the prediction of protein-ligand binding affinities. A number of test systems were examined, including harmonic oscillator (HO) systems and the calculation of relative free energies of hydration of water-methane. The latter system uses identical potentials to the protein ligand case and is therefore an appropriate model system on which methods may be tested. As well as investigating existing protocols, a replica exchange NE approach was developed, which was found to offer advantages over conventional methods. It was found that Rosenbluth-based approaches to optimizing the NE work values used in NE free energy estimates were not consistent in the improvements in accuracy achieved and that, given their computational cost, the simple approach of taking each work value in an unbiased way is to be preferred. Of the two free energy estimators examined, Bennett's acceptance ratio was the most consistent and is, therefore, to be preferred over the Jarzynski estimator. The recommended protocols may be run very efficiently within a distributed computing environment and are of similar accuracy and precision to equilibrium free energy methods.

  20. Experimental studies in non-equilibrium physics

    Science.gov (United States)

    Cressman, John Robert, Jr.

    This work is a collection of three experiments aimed at studying different facets of non-equilibrium dynamics. Chapter I concerns strongly compressible turbulence, which turns out to be very different from incompressible turbulence. The focus is on the dispersion of contaminants in such a flow. This type of turbulence can be studied, at very low mach number, by measuring the velocity fields of particles that float on a turbulently stirred body of water. It turns out that in the absence of incompressibility, the turbulence causes particles to cluster rather than to disperse. The implications of the observations are far reaching and include the transport of pollutants on the oceans surface, phytoplankton growth, as well as industrial applications. Chapter II deals with the effects of polymer additives on drag reduction and turbulent suppression, a well-known phenomenon that is not yet understood. In an attempt to simplify the problem, the effects of a polymer additive were investigated in a vortex street formed in a flowing soap film. Measurements suggest that an increase in elongational viscosity is responsible for a substantial reduction in periodic velocity fluctuations. This study also helps to illuminate the mechanism responsible for vortex separation in the wake of a bluff body. Chapter III describes an experiment designed to test a theoretical approach aimed at generalizing the classical fluctuation dissipation theorem (FDT). This theorem applies to systems driven only slightly away from thermal equilibrium, whereas ours, a liquid crystal under-going electroconvection, is so strongly driven, that the FDT does not apply. Both theory and experiment focus on the flux in global power fluctuations. Physical limitations did not permit a direct test of the theory, however it was possible to establish several interesting characteristics of the system: the source of the fluctuations is the transient defect structures that are generated when the system is driven hard

  1. Fractional Fourier processing of quantum light.

    Science.gov (United States)

    Sun, Yifan; Tao, Ran; Zhang, Xiangdong

    2014-01-13

    We have extended Fourier transform of quantum light to a fractional Fourier processing, and demonstrated that a classical optical fractional Fourier processor can be used for the shaping of quantum correlations between two or more photons. Comparing the present method with that of Fourier processing, we find that fractional Fourier processing for quantum light possesses many advantages. Based on such a method, not only quantum correlations can be shaped more rich, but also the initial states can be easily identified. Moreover, the twisted phase information can be recovered and quantum states are easily controlled in performing quantum information experiments. Our findings open up new avenues for the manipulation of correlations between photons in optical quantum information processing.

  2. Neutron Fourier diffractometer FSD for internal stress analysis: first results

    Science.gov (United States)

    Bokuchava, G. D.; Aksenov, V. L.; Balagurov, A. M.; Kuzmin, E. S.; Zhuravlev, V. V.; Bulkin, A. P.; Kudryashev, V. A.; Trounov, V. A.

    At the IBR-2 pulsed reactor in Dubna a new neutron Fourier diffractometer FSD is under construction. FSD continues the development of neutron Fourier diffractometry at long-pulse neutron sources, which was started several years ago with the high-resolution Fourier diffractometer HRFD at the IBR-2. Whereas HRFD is mainly used for precise structural refinement, FSD is optimised for internal stress measurements in bulk materials. The FSD design satisfies the requirements of high luminosity, high resolution, a specific sample environment, a wide range of dhkl, and fixed scattering angles 2θ=+/-90°. It consists of a mirror neutron guide, a fast Fourier chopper for the neutron-beam intensity modulation, a +/-90° MultiCon ZnS(Ag) 6Li-loaded detector system with both geometrical and electronic focusing, a five-axis goniometer `Huber' and loading machines, and VME-based RTOF analysers for data acquisition. Examples of the first experimental results obtained with FSD are presented.

  3. Comparison of changes in the secondary structure of unheated, heated, and high-pressure-treated beta-lactoglobulin and ovalbumin proteins using fourier transform raman spectroscopy and self-deconvolution.

    Science.gov (United States)

    Ngarize, Sekai; Herman, Henryk; Adams, Alf; Howell, Nazlin

    2004-10-20

    Changes in protein secondary structure and conformation of ovalbumin and beta-lactoglobulin (15% protein w/w) were investigated by Fourier transform Raman spectroscopy and self-deconvolution. The amounts of alpha-helix, beta-sheets, random coil, and beta-turns in native beta-lactoglobulin were 15, 54, 6, and 25%, respectively, and those for ovalbumin (41, 34, 13, and 12%) compared well with published values obtained by X-ray crystallography. The proteins were heated at 90 degrees C for 30 min and high-pressure-treated at 600 MPa for 20 min. Heating increased beta-sheet structures in both proteins at the expense of alpha-helix; for beta-lactoglobulin beta-sheet structures increased from 54 to 70% and for ovalbumin, from 34 to 54%. Random coil increased from 6% in the native protein to 30% in high-pressure-treated beta-lactoglobulin. However, for ovalbumin, the contribution from beta-turns doubled in high-pressure-treated samples, with little change in random coil. Further examination of the deconvoluted amide I band in heated samples revealed several component bands. Bands at 1626 and 1682 cm(-1) for ovalbumin and at 1625 and 1680 cm(-1) for beta-lactoglobulin were observed and are associated with aggregated, intermolecular beta-sheet (beta-aggregation), indicative of heat denaturation. The band seen at 1632-1640 cm(-1) corresponded to intramolecular beta-sheet structures, whereas the band at 1625 cm(-1) is associated with exposed beta-sheets (for example, beta-strands with strong hydrogen bonding that are not part of the core of beta-sheets). In high-pressure-treated samples bands were also observed at 1628 and 1680 cm(-1) for ovalbumin and at 1626 and 1684 cm(-1) for beta-lactoglobulin, suggesting involvement of beta-sheet structures in protein aggregation. Raman bands were observed at 1665-1670 cm(-1) for ovalbumin and at 1663-1675 cm(-1) for beta-lactoglobulin due to random coil structures. The bands at 1650-1660 cm(-1) due to alpha-helices were observed in both

  4. Nonequilibrium Dynamical Mean-Field Theory for Bosonic Lattice Models

    Directory of Open Access Journals (Sweden)

    Hugo U. R. Strand

    2015-03-01

    Full Text Available We develop the nonequilibrium extension of bosonic dynamical mean-field theory and a Nambu real-time strong-coupling perturbative impurity solver. In contrast to Gutzwiller mean-field theory and strong-coupling perturbative approaches, nonequilibrium bosonic dynamical mean-field theory captures not only dynamical transitions but also damping and thermalization effects at finite temperature. We apply the formalism to quenches in the Bose-Hubbard model, starting from both the normal and the Bose-condensed phases. Depending on the parameter regime, one observes qualitatively different dynamical properties, such as rapid thermalization, trapping in metastable superfluid or normal states, as well as long-lived or strongly damped amplitude oscillations. We summarize our results in nonequilibrium “phase diagrams” that map out the different dynamical regimes.

  5. Free energy for non-equilibrium quasi-stationary states

    Science.gov (United States)

    Allahverdyan, A. E.; Martirosyan, N. H.

    2017-03-01

    We study a class of non-equilibrium quasi-stationary states for a Markov system interacting with two different thermal baths. We show that the work done under a slow, external change of parameters admits a potential, i.e., the free energy. Three conditions are needed for the existence of free energy in this non-equilibrium system: time-scale separation between variables of the system, partial controllability (external fields couple only with the slow variable), and an effective detailed balance. These conditions are facilitated in the continuous limit for the slow variable. In contrast to its equilibrium counterpart, the non-equilibrium free energy can increase with temperature. One example of this is that entropy reduction by means of external fields (cooling) can be easier (in the sense of the work cost) if it starts from a higher temperature.

  6. Landscape and flux theory of non-equilibrium open economy

    Science.gov (United States)

    Zhang, Kun; Wang, Jin

    2017-09-01

    The economy is open and never in true equilibrium due to the exchanges with outside. However, most of the quantitative studies have been focused on the equilibrium economy. Despite of the recent efforts, it is still challenging to formulate a quantitative theory for uncovering the principles of non-equilibrium open economy. In this study, we developed a landscape and flux theory for non-equilibrium economy. We quantified the states of economy and identify the multi-stable states as the basins of attractions on the underlying landscape. We found the global driving force of the non-equilibrium economy is determined by both the underlying landscape gradient and the curl probability flux measuring the degree of non-equilibriumness through the detailed balance breaking. The non-equilibrium thermodynamics, the global stability, the optimal path and speed of the non-equilibrium economy can be formulated and quantified. In the conventional economy, the supply and demand usually has only one equilibrium. By considering nonlinear supply-demand dynamics, we found that both bi-stable states and limit cycle oscillations can emerge. By shifting the slope of demand curve, we can see how the bi-stability transforms to the limit cycle dynamics and vice versa. By parallel shifting the demand curve, we can also see how the monopoly, the competition, and the bistable monopoly and competition states emerge and transform to one other. We can also see how the mono-stable monopoly, the limit cycle and the mono-stable competition states emerge and transform to one another.

  7. Warm non-equilibrium gas phase chemistry as a possible origin of high HDO/H2O ratios in hot and dense gases : application to inner protoplanetary discs

    NARCIS (Netherlands)

    Thi, W. -F.; Woitke, P.; Kamp, I.

    2010-01-01

    The origin of Earth oceans is controversial. Earth could have acquired its water either from hydrated silicates (wet Earth scenario) or from comets (dry Earth scenario). [HDO]/[H2O] ratios are used to discriminate between the scenarios. High [HDO]/[H2O] ratios are found in Earth oceans. These high

  8. High-throughput and high-sensitivity quantitative analysis of serum unsaturated fatty acids by chip-based nanoelectrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry: early stage diagnostic biomarkers of pancreatic cancer.

    Science.gov (United States)

    Zhang, Yaping; Qiu, Ling; Wang, Yanmin; Qin, Xuzhen; Li, Zhili

    2014-04-07

    In this study, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) coupled with chip-based direct-infusion nanoelectrospray ionization source (CBDInanoESI) in a negative ion mode is first employed to evaluate the effect of serum and its corresponding supernatant matrixes on the recoveries of serum free fatty acids (FFAs) based on spike-and-recovery experimental strategy by adding analytes along with analog internal standard (IS). The recoveries between serum (69.8-115.6%) and the supernatant (73.6-99.0%) matrixes are almost identical. Multiple point internal standard calibration curves between the concentration ratios of individual fatty acids to ISs, (C(17:1) as IS of C(16:1), C(18:3), C(18:2), or C(18:1) or C(21:0) as IS of C(20:4) or C(22:6)) versus their corresponding intensity ratios were constructed for C(16:1), C(18:3), C(18:2), C(18:1), C(20:4) and C(22:6), respectively, with correlation coefficients of greater than 0.99, lower limits of detection between 0.3 and 1.8 nM, and intra- and inter-day precision (relative standard deviations <18%), along with the linear dynamic range of three orders of magnitude. Sequentially, this advanced analytical platform was applied to perform simultaneous quantitative and qualitative analysis of multiple targets, e.g., serum supernatant unsaturated FFAs from 361 participants including 95 patients with pancreatic cancer (PC), 61 patients with pancreatitis and 205 healthy controls. Experimental results indicate that the levels of C(18:1), C(18:2), C(18:3), C(20:4) and C(22:6), as well as the level ratios of C(18:2)/C(18:1) and C(18:3)/C(18:1) of the PC patients were significantly decreased compared with those of healthy controls and the patients with pancreatitis (p < 0.01). It is worth noting that the ratio of C(18:2)/C(18:1), polyunsaturated fatty acids (PUFAs) (C(18:2), C(18:3), C(20:4), and C(22:6)), panel a (C(16:1), C(18:3), C(18:2), C(20:4) and C(22:6)) and panel b (C(18:2)/C(18:1) and C(18:3)/C(18

  9. Carbon vaporization into a nonequilibrium, stagnation-point boundary layer

    Science.gov (United States)

    Suzuki, T.

    1978-01-01

    The heat transfer to the stagnation point of an ablating carbonaceous heat shield, where both the gas-phase boundary layer and the heterogeneous surface reactions are not in chemical equilibrium, is examined. Specifically, the nonequilibrium changes in the mass fraction profiles of carbon species calculated for frozen flow are studied. A set of equations describing the steady-state, nonequilibrium laminar boundary layer in the axisymmetric stagnation region, over an ablating graphite surface, is solved, with allowance for the effects of finite rate of carbon vaporization.

  10. Convection with local thermal non-equilibrium and microfluidic effects

    CERN Document Server

    Straughan, Brian

    2015-01-01

    This book is one of the first devoted to an account of theories of thermal convection which involve local thermal non-equilibrium effects, including a concentration on microfluidic effects. The text introduces convection with local thermal non-equilibrium effects in extraordinary detail, making it easy for readers newer to the subject area to understand. This book is unique in the fact that it addresses a large number of convection theories and provides many new results which are not available elsewhere. This book will be useful to researchers from engineering, fluid mechanics, and applied mathematics, particularly those interested in microfluidics and porous media.

  11. Mathematical theory of non-equilibrium quantum statistical mechanics

    CERN Document Server

    Jaksic, V

    2001-01-01

    We review and further develop a mathematical framework for non-equilibrium quantum statistical mechanics recently proposed in [JP4, JP5, JP6, Ru3, Ru4, Ru5, Ru6]. In the algebraic formalism of quantum statistical mechanics we introduce notions of non-equilibrium steady states, entropy production and heat fluxes, and study their properties. Our basic paradigm is a model of a small (finite) quantum system coupled to several independent thermal reservoirs. We exhibit examples of such systems which have strictly positive entropy production.

  12. Introduction to non-equilibrium quantum statistical mechanics

    CERN Document Server

    Aschbacher, W; Pautrat, Y; Pillet, C A

    2005-01-01

    These notes are an expanded version of the lectures given by the second and fourth autor in the summer school "Open Quantum System" held in Grenoble, June 16-July 4, 2003. They provide an introduction to recent developments in non-equilibrium statistical mechanics of open quantum systems, including a completely worked out (simple) example. We discuss non-equilibrium steady states (NESS) and their structural properties, entropy production, linear response theory and weak coupling limit. The emphasis is on Ruelle's scattering approach to the construction of NESS.

  13. Topics in non-equilibrium quantum statistical mechanics

    CERN Document Server

    Aschbacher, W; Pautrat, Y; Pillet, C

    2005-01-01

    These notes are an expanded and revised version of the lectures given by the second and fourth autor in the summer school "Open Quantum System" held in Grenoble, June 16-July 4, 2003. They provide an introduction to recent developments in non-equilibrium statistical mechanics of open quantum systems, including a completely worked out (simple) example. We discuss non-equilibrium steady states (NESS) and their structural properties, entropy production, linear response theory and weak coupling limit. The emphasis is on Ruelle's scattering approach to the construction of NESS.

  14. Bright solitons in non-equilibrium coherent quantum matter.

    Science.gov (United States)

    Pinsker, F; Flayac, H

    2016-01-01

    We theoretically demonstrate a mechanism for bright soliton generation in spinor non-equilibrium Bose-Einstein condensates made of atoms or quasi-particles such as polaritons in semiconductor microcavities. We give analytical expressions for bright (half) solitons as minimizing functions of a generalized non-conservative Lagrangian elucidating the unique features of inter and intra-competition in non-equilibrium systems. The analytical results are supported by a detailed numerical analysis that further shows the rich soliton dynamics inferred by their instability and mutual cross-interactions.

  15. Non-equilibrium quantum phase transition via entanglement decoherence dynamics

    Science.gov (United States)

    Lin, Yu-Chen; Yang, Pei-Yun; Zhang, Wei-Min

    2016-10-01

    We investigate the decoherence dynamics of continuous variable entanglement as the system-environment coupling strength varies from the weak-coupling to the strong-coupling regimes. Due to the existence of localized modes in the strong-coupling regime, the system cannot approach equilibrium with its environment, which induces a nonequilibrium quantum phase transition. We analytically solve the entanglement decoherence dynamics for an arbitrary spectral density. The nonequilibrium quantum phase transition is demonstrated as the system-environment coupling strength varies for all the Ohmic-type spectral densities. The 3-D entanglement quantum phase diagram is obtained.

  16. Non-equilibrium quantum phase transition via entanglement decoherence dynamics.

    Science.gov (United States)

    Lin, Yu-Chen; Yang, Pei-Yun; Zhang, Wei-Min

    2016-10-07

    We investigate the decoherence dynamics of continuous variable entanglement as the system-environment coupling strength varies from the weak-coupling to the strong-coupling regimes. Due to the existence of localized modes in the strong-coupling regime, the system cannot approach equilibrium with its environment, which induces a nonequilibrium quantum phase transition. We analytically solve the entanglement decoherence dynamics for an arbitrary spectral density. The nonequilibrium quantum phase transition is demonstrated as the system-environment coupling strength varies for all the Ohmic-type spectral densities. The 3-D entanglement quantum phase diagram is obtained.

  17. Generalization of the second law for a nonequilibrium initial state

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H.-H., E-mail: hhh@mx.ibaraki.ac.j [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Ishikawa, J.; Takara, K. [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Driebe, D.J. [Division of Math, Science and Technology, Nova Southeastern University, Fort Lauderdale, FL 33314 (United States)

    2010-02-08

    We generalize the second law of thermodynamics in its maximum work formulation for a nonequilibrium initial distribution. It is found that in an isothermal process, the Boltzmann relative entropy (H-function) is not just a Lyapunov function but also tells us the maximum work that may be gained from a nonequilibrium initial state. The generalized second law also gives a fundamental relation between work and information. It is valid even for a small Hamiltonian system not in contact with a heat reservoir but with an effective temperature determined by the isentropic condition. Our relation can be tested in the Szilard engine, which will be realized in the laboratory.

  18. Principle of Entropy Maximization for Nonequilibrium Steady States

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2002-01-01

    has a maximum in a steady state with regard to some thermodynamic variables, the matrix of the Onsager phenomenological coefficients becomes diagonal. The theorem requires consistent rules of the coordinate transformations in the non-equilibrium thermodynamics. Such rules are formulated. The results......The goal of this contribution is to find out to what extent the principle of entropy maximization, which serves as a basis for the equilibrium thermodynamics, may be generalized onto non-equilibrium steady states. We prove a theorem that, in the system of thermodynamic coordinates, where entropy...

  19. A Characterization of Conserved Quantities in Non-Equilibrium Thermodynamics

    Directory of Open Access Journals (Sweden)

    Ignacio Romero

    2013-12-01

    Full Text Available The well-known Noether theorem in Lagrangian and Hamiltonian mechanics associates symmetries in the evolution equations of a mechanical system with conserved quantities. In this work, we extend this classical idea to problems of non-equilibrium thermodynamics formulated within the GENERIC (General Equations for Non-Equilibrium Reversible-Irreversible Coupling framework. The geometric meaning of symmetry is reviewed in this formal setting and then utilized to identify possible conserved quantities and the conditions that guarantee their strict conservation. Examples are provided that demonstrate the validity of the proposed definition in the context of finite and infinite dimensional thermoelastic problems.

  20. Fourier transforms in radar and signal processing

    CERN Document Server

    Brandwood, David

    2011-01-01

    Fourier transforms are used widely, and are of particular value in the analysis of single functions and combinations of functions found in radar and signal processing. Still, many problems that could have been tackled by using Fourier transforms may have gone unsolved because they require integration that is difficult and tedious. This newly revised and expanded edition of a classic Artech House book provides you with an up-to-date, coordinated system for performing Fourier transforms on a wide variety of functions. Along numerous updates throughout the book, the Second Edition includes a crit

  1. Non-equilibrium superconductivity in a correlated electron system studied with the Keldysh+FLEX approach

    OpenAIRE

    Oka, Takashi; Aoki, Hideo

    2010-01-01

    Non-equilibrium phase transitions are studied theoretically for the two-dimensional Hubbard model subject to bias voltages from the electrodes coupled to the system. By combining the fluctuation exchange approximation with the Keldysh method for non-equilibrium, we have studied the properties of the non-equilibrium Fermi liquid phase and determined the phase diagram with transition to non-equilibrium magnetic and superconducting phases.

  2. Fundamental Properties of Non-equilibrium Laser-Supported Detonation Wave

    Science.gov (United States)

    Shiraishi, Hiroyuki

    2004-03-01

    For developing laser propulsion, it is very important to analyze the mechanism of Laser-Supported Detonation (LSD), because it can generate high pressure and high temperature to be used by laser propulsion can be categorized as one type of hypersonic reacting flows, where exothermicity is supplied not by chemical reaction but by radiation absorption. I have numerically simulated the 1-D and Quasi-1-D LSD waves propagating through an inert gas, which absorbs CO2 gasdynamic laser, using a 2-temperature model. Calculated results show the fundamental properties of the non-equilibrium LSD Waves.

  3. Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

    Science.gov (United States)

    Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

    2016-09-19

    The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

  4. Final Report on DTRA Basic Research Project #BRCALL08-Per3-C-2-0006 "High-Z Non-Equilibrium Physics and Bright X-ray Sources with New Laser Targets"

    Energy Technology Data Exchange (ETDEWEB)

    Colvin, Jeffrey D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-06-01

    This project had two major goals. Final Goal: obtain spectrally resolved, absolutely calibrated x-ray emission data from uniquely uniform mm-scale near-critical-density high-Z plasmas not in local thermodynamic equilibrium (LTE) to benchmark modern detailed atomic physics models. Scientific significance: advance understanding of non-LTE atomic physics. Intermediate Goal: develop new nano-fabrication techniques to make suitable laser targets that form the required highly uniform non-LTE plasmas when illuminated by high-intensity laser light. Scientific significance: advance understanding of nano-science. The new knowledge will allow us to make x-ray sources that are bright at the photon energies of most interest for testing radiation hardening technologies, the spectral energy range where current x-ray sources are weak. All project goals were met.

  5. Gene expression model (in)validation by Fourier analysis.

    Science.gov (United States)

    Konopka, Tomasz; Rooman, Marianne

    2010-09-03

    The determination of the right model structure describing a gene regulation network and the identification of its parameters are major goals in systems biology. The task is often hampered by the lack of relevant experimental data with sufficiently low noise level, but the subset of genes whose concentration levels exhibit an oscillatory behavior in time can readily be analyzed on the basis of their Fourier spectrum, known to turn complex signals into few relatively noise-free parameters. Such genes therefore offer opportunities of understanding gene regulation quantitatively. Fourier analysis is applied to data on gene expression levels in mouse liver cells that oscillate according to the circadian rhythm. Several model structures in the form of linear and nonlinear differential equations are matched to the data and it is shown that although the considered models can reproduce many features of the oscillatory patterns, some can be excluded on the basis of Fourier analysis without appeal to prior knowledge of regulatory pathways. A systematic method for testing models is also proposed based on measuring the effects of variations in gene copy-number on the expression levels of coupled genes. Fourier analysis is a technique that is well-adapted to the study of biological oscillators and can be used instead or in addition to conventional modeling techniques. Its usefulness will increase as more high-resolution data become available.

  6. Improved fast fractional-Fourier-transform algorithm.

    Science.gov (United States)

    Yang, Xingpeng; Tan, Qiaofeng; Wei, Xiaofeng; Xiang, Yong; Yan, Yingbai; Jin, Guofan

    2004-09-01

    Through the optimization of the main interval of the fractional order, an improved fast algorithm for numerical calculation of the fractional Fourier transforms is proposed. With this improved algorithm, the fractional Fourier transforms of a rectangular function and a Gaussian function are calculated. Its calculation errors are compared with those calculated with the previously published algorithm, and the results show that the calculation accuracy of the improved algorithm is much higher.

  7. Implementation of quantum and classical discrete fractional Fourier transforms

    OpenAIRE

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gr?fe, Markus; Heilmann, Ren?; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N.; Szameit, Alexander

    2016-01-01

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discre...

  8. Spacecraft Sterilization Using Non-Equilibrium Atmospheric Pressure Plasma

    Science.gov (United States)

    Cooper, Moogega; Vaze, Nachiket; Anderson, Shawn; Fridman, Gregory; Vasilets, Victor N.; Gutsol, Alexander; Tsapin, Alexander; Fridman, Alexander

    2007-01-01

    As a solution to chemically and thermally destructive sterilization methods currently used for spacecraft, non-equilibrium atmospheric pressure plasmas are used to treat surfaces inoculated with Bacillus subtilis and Deinococcus radiodurans. Evidence of significant morphological changes and reduction in viability due to plasma exposure will be presented, including a 4-log reduction of B. subtilis after 2 minutes of dielectric barrier discharge treatment.

  9. Simulation and comparison of equilibrium and nonequilibrium stage ...

    African Journals Online (AJOL)

    In the present study, two distinctly different approaches are followed for modelling of reactive distillation column, the equilibrium stage model and the nonequilibrium stage model. These models are simulated with a computer code developed in the present study using MATLAB programming. In the equilibrium stage models, ...

  10. Decondensation in Nonequilibrium Photonic Condensates: When Less Is More

    Science.gov (United States)

    Hesten, Henry J.; Nyman, Robert A.; Mintert, Florian

    2018-01-01

    We investigate the steady state of a system of photons in a pumped dye-filled microcavity. By varying pump and thermalization the system can be tuned between Bose-Einstein condensation, multimode condensation, and lasing. We present a rich nonequilibrium phase diagram which exhibits transitions between these phases, including decondensation of individual modes under conditions that would typically favor condensation.

  11. Fluctuation theorems and orbital magnetism in nonequilibrium state

    Indian Academy of Sciences (India)

    rare and are related to transient second law violating contributions. These theo- rems are useful to probe nonequilibrium states in nanophysics and biology. In these systems energies involved are typically small and hence thermal fluctuations play a significant role. In fact, variance in some of the physical quantities dominate.

  12. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    For systems in contact with two reservoirs at different densities or with two thermostats at different temperatures, the large deviation function of the density gives a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for ...

  13. Nonequilibrium Enhances Adaptation Efficiency of Stochastic Biochemical Systems.

    Directory of Open Access Journals (Sweden)

    Chen Jia

    Full Text Available Adaptation is a crucial biological function possessed by many sensory systems. Early work has shown that some influential equilibrium models can achieve accurate adaptation. However, recent studies indicate that there are close relationships between adaptation and nonequilibrium. In this paper, we provide an explanation of these two seemingly contradictory results based on Markov models with relatively simple networks. We show that as the nonequilibrium driving becomes stronger, the system under consideration will undergo a phase transition along a fixed direction: from non-adaptation to simple adaptation then to oscillatory adaptation, while the transition in the opposite direction is forbidden. This indicates that although adaptation may be observed in equilibrium systems, it tends to occur in systems far away from equilibrium. In addition, we find that nonequilibrium will improve the performance of adaptation by enhancing the adaptation efficiency. All these results provide a deeper insight into the connection between adaptation and nonequilibrium. Finally, we use a more complicated network model of bacterial chemotaxis to validate the main results of this paper.

  14. Fluctuation theorems and orbital magnetism in nonequilibrium state

    Indian Academy of Sciences (India)

    We study Langevin dynamics of a driven charged particle in the presence as well as in the absence of magnetic field. We discuss the validity of various work fluctuation theorems using different model potentials and external drives. We also show that one can generate an orbital magnetic moment in a nonequilibrium state ...

  15. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    systems. Keywords. Non-equilibrium systems; large deviations; current fluctuations. PACS Nos 02.50.-r; 05.40.-a; 05.70.Ln; 82.20.-w. 1. Introduction. The goal of this talk is to give a short review on results [1–8] obtained recently on the steady .... binary variable indicating whether site i is occupied or empty, the time evolution.

  16. Accelerated radial Fourier-velocity encoding using compressed sensing.

    Science.gov (United States)

    Hilbert, Fabian; Wech, Tobias; Hahn, Dietbert; Köstler, Herbert

    2014-09-01

    Phase Contrast Magnetic Resonance Imaging (MRI) is a tool for non-invasive determination of flow velocities inside blood vessels. Because Phase Contrast MRI only measures a single mean velocity per voxel, it is only applicable to vessels significantly larger than the voxel size. In contrast, Fourier Velocity Encoding measures the entire velocity distribution inside a voxel, but requires a much longer acquisition time. For accurate diagnosis of stenosis in vessels on the scale of spatial resolution, it is important to know the velocity distribution of a voxel. Our aim was to determine velocity distributions with accelerated Fourier Velocity Encoding in an acquisition time required for a conventional Phase Contrast image. We imaged the femoral artery of healthy volunteers with ECG-triggered, radial CINE acquisition. Data acquisition was accelerated by undersampling, while missing data were reconstructed by Compressed Sensing. Velocity spectra of the vessel were evaluated by high resolution Phase Contrast images and compared to spectra from fully sampled and undersampled Fourier Velocity Encoding. By means of undersampling, it was possible to reduce the scan time for Fourier Velocity Encoding to the duration required for a conventional Phase Contrast image. Acquisition time for a fully sampled data set with 12 different Velocity Encodings was 40 min. By applying a 12.6-fold retrospective undersampling, a data set was generated equal to 3:10 min acquisition time, which is similar to a conventional Phase Contrast measurement. Velocity spectra from fully sampled and undersampled Fourier Velocity Encoded images are in good agreement and show the same maximum velocities as compared to velocity maps from Phase Contrast measurements. Compressed Sensing proved to reliably reconstruct Fourier Velocity Encoded data. Our results indicate that Fourier Velocity Encoding allows an accurate determination of the velocity distribution in vessels in the order of the voxel size. Thus

  17. Topics in Statistical Physics: Protein Stability, Non-Equilibrium Thermodynamics and Bibliometrics

    Science.gov (United States)

    Hazoglou, Michael

    This dissertation will cover three distinct topics of protein stability, non-equilibrium thermodynamics and scientometrics. In senescent organisms aging is correlated with oxidative damage of proteins. The damage done to proteins destabilizes them inhibiting their function. The implications of a simplified model based on side-chain modification of charged residues using Debye-Hückel theory will be presented. Short length and highly charged proteins are susceptible to destabilization from oxidative damage. Among these proteins already studied in aging several proteins fit this description of being short and highly charged. There is a noticeable enrichment of short-highly-charged proteins in categories of proteins known to be important in aging. Maximum Caliber (MaxCal) is a potential theory of non-equilibrium statistical mechanics. It will be shown how MaxCal is used to derive the Onsager reciprocal relations, Green-Kubo relations and Prigogine's Principle and extend these relations beyond the near-equilibrium regime. The last topic is the citation and publication trends of papers and authors, respectively. A discussion of how pure-birth processes can be applied to understanding citation trends and how birth-processes can be used in classifying papers into different categories of performance.

  18. From high symmetry to high resolution in biological electron microscopy: a commentary on Crowther (1971) ‘Procedures for three-dimensional reconstruction of spherical viruses by Fourier synthesis from electron micrographs’

    Science.gov (United States)

    Rosenthal, Peter B.

    2015-01-01

    Elucidation of the structure of biological macromolecules and larger assemblies has been essential to understanding the roles they play in living processes. Methods for three-dimensional structure determination of biological assemblies from images recorded in the electron microscope were therefore a key development. In his paper published in Philosophical Transactions B in 1971, Crowther described new computational procedures applied to the first three-dimensional reconstruction of an icosahedral virus from images of virus particles preserved in negative stain. The method for determining the relative orientation of randomly oriented particles and combining their images for reconstruction exploited the high symmetry of the virus particle. Computational methods for image analysis have since been extended to include biological assemblies without symmetry. Further experimental advances, combined with image analysis, have led to the method of cryomicroscopy, which is now used by structural biologists to study the structure and dynamics of biological machines and assemblies in atomic detail. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750240

  19. From high symmetry to high resolution in biological electron microscopy: a commentary on Crowther (1971) 'Procedures for three-dimensional reconstruction of spherical viruses by Fourier synthesis from electron micrographs'.

    Science.gov (United States)

    Rosenthal, Peter B

    2015-04-19

    Elucidation of the structure of biological macromolecules and larger assemblies has been essential to understanding the roles they play in living processes. Methods for three-dimensional structure determination of biological assemblies from images recorded in the electron microscope were therefore a key development. In his paper published in Philosophical Transactions B in 1971, Crowther described new computational procedures applied to the first three-dimensional reconstruction of an icosahedral virus from images of virus particles preserved in negative stain. The method for determining the relative orientation of randomly oriented particles and combining their images for reconstruction exploited the high symmetry of the virus particle. Computational methods for image analysis have since been extended to include biological assemblies without symmetry. Further experimental advances, combined with image analysis, have led to the method of cryomicroscopy, which is now used by structural biologists to study the structure and dynamics of biological machines and assemblies in atomic detail. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

  20. Fast Fourier projection for MR angiography.

    Science.gov (United States)

    Napel, S; Dunne, S; Rutt, B K

    1991-06-01

    We have developed a technique called fast Fourier projection which rapidly produces projections through images and is particularly useful for generating MR angiograms. Based on the projection-slice theorem of Fourier transform theory, this method extracts planes from three-dimensional spatial frequency space and computes projections at arbitrary viewing angles by two-dimensional inverse Fourier transformation. Typical computation times are on the order of 1 s per projection. This performance makes possible interactive selection of optimal projection directions for visualizing the desired vasculature in single or stereo-pair angiographic images and drastically reduces the time required to generate sequences of projections for display in movie loops compared to the conventional ray-casting approach. The method is easily implemented on off-line workstations or directly on MRI computer systems.

  1. Methods of Fourier analysis and approximation theory

    CERN Document Server

    Tikhonov, Sergey

    2016-01-01

    Different facets of interplay between harmonic analysis and approximation theory are covered in this volume. The topics included are Fourier analysis, function spaces, optimization theory, partial differential equations, and their links to modern developments in the approximation theory. The articles of this collection were originated from two events. The first event took place during the 9th ISAAC Congress in Krakow, Poland, 5th-9th August 2013, at the section “Approximation Theory and Fourier Analysis”. The second event was the conference on Fourier Analysis and Approximation Theory in the Centre de Recerca Matemàtica (CRM), Barcelona, during 4th-8th November 2013, organized by the editors of this volume. All articles selected to be part of this collection were carefully reviewed.

  2. Fourier analysis and boundary value problems

    CERN Document Server

    Gonzalez-Velasco, Enrique A

    1996-01-01

    Fourier Analysis and Boundary Value Problems provides a thorough examination of both the theory and applications of partial differential equations and the Fourier and Laplace methods for their solutions. Boundary value problems, including the heat and wave equations, are integrated throughout the book. Written from a historical perspective with extensive biographical coverage of pioneers in the field, the book emphasizes the important role played by partial differential equations in engineering and physics. In addition, the author demonstrates how efforts to deal with these problems have lead to wonderfully significant developments in mathematics.A clear and complete text with more than 500 exercises, Fourier Analysis and Boundary Value Problems is a good introduction and a valuable resource for those in the field.Key Features* Topics are covered from a historical perspective with biographical information on key contributors to the field* The text contains more than 500 exercises* Includes practical applicati...

  3. Practical Fourier analysis for multigrid methods

    CERN Document Server

    Wienands, Roman

    2004-01-01

    Before applying multigrid methods to a project, mathematicians, scientists, and engineers need to answer questions related to the quality of convergence, whether a development will pay out, whether multigrid will work for a particular application, and what the numerical properties are. Practical Fourier Analysis for Multigrid Methods uses a detailed and systematic description of local Fourier k-grid (k=1,2,3) analysis for general systems of partial differential equations to provide a framework that answers these questions.This volume contains software that confirms written statements about convergence and efficiency of algorithms and is easily adapted to new applications. Providing theoretical background and the linkage between theory and practice, the text and software quickly combine learning by reading and learning by doing. The book enables understanding of basic principles of multigrid and local Fourier analysis, and also describes the theory important to those who need to delve deeper into the detai...

  4. Fourier duality as a quantization principle

    Energy Technology Data Exchange (ETDEWEB)

    Aldrovandi, R.; Saeger, L.A.

    1996-08-01

    The Weyl-Wigner prescription for quantization on Euclidean phase spaces makes essential use of Fourier duality. The extension of this property to more general phase spaces requires the use of Kac algebras, which provide the necessary background for the implementation of Fourier duality on general locally groups. Kac algebras - and the duality they incorporate are consequently examined as candidates for a general quantization framework extending the usual formalism. Using as a test case the simplest non-trivial phase space, the half-plane, it is shown how the structures present in the complete-plane case must be modified. Traces, for example, must be replaced by their noncommutative generalizations - weights - and the correspondence embodied in the Weyl-Wigner formalism is no more complete. Provided the underlying algebraic structure is suitably adapted to each case, Fourier duality is shown to be indeed a very powerful guide to the quantization of general physical systems. (author). 30 refs.

  5. Second-order fractional Fourier transform with incoherent radiation.

    Science.gov (United States)

    Cai, Yangjian; Zhu, Shi-Yao

    2005-02-15

    Based on the coherent optical theory, we extend the fractional Fourier transform of first-order correlation to a fractional Fourier transform of second-order correlation. An optical system for implementing a second-order fractional Fourier transform was designed. As a numerical example, we investigate the second-order fractional Fourier transform for a single slit.

  6. Time-Domain Optical Fourier Transformation for OTDM-DWDM and DWDM-OTDM Conversion

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Galili, Michael

    2011-01-01

    Applications of time-domain optical Fourier transformation (OFT) in ultra-high-speed optical time-division multiplexed systems (OTDM) are reviewed, with emphasis on the recent demonstrations of OFT-based conversion between the OTDM and DWDM formats.......Applications of time-domain optical Fourier transformation (OFT) in ultra-high-speed optical time-division multiplexed systems (OTDM) are reviewed, with emphasis on the recent demonstrations of OFT-based conversion between the OTDM and DWDM formats....

  7. Intermittency in Fractal Fourier Hydrodynamics: Lessons from the Burgers Equation

    CERN Document Server

    Buzzicotti, Michele; Frisch, Uriel; Ray, Samriddhi Sankar

    2016-01-01

    We present theoretical and numerical results for the one-dimensional stochastically forced Burgers equation decimated on a fractal Fourier set of dimension $D$. We investigate the robustness of the energy transfer mechanism and of the small-scale statistical fluctuations by changing $D$. We find that a very small percentage of mode-reduction ($D \\lesssim 1$) is enough to destroy most of the characteristics of the original non-decimated equation. In particular, we observe a suppression of intermittent fluctuations for $D <1$ and a quasi-singular transition from the fully intermittent ($D=1$) to the non-intermittent case for $D \\lesssim 1$. Our results indicate that the existence of strong localized structures (shocks) in the one-dimensional Burgers equation is the result of highly entangled correlations amongst all Fourier modes.

  8. Group-based sparse representation for Fourier ptychography microscopy

    Science.gov (United States)

    Zhang, Yongbing; Cui, Ze; Zhang, Jian; Song, Pengming; Dai, Qionghai

    2017-12-01

    Fourier ptychography microscopy (FPM), which employs alternative projection between spatial and Fourier domains to stitch low-resolution images captured under angularly varying illumination, reconstructs one image with high-resolution and wide field of view (FOV) to bypass the limitation of the space-bandwidth product (SBP) of the traditional optical system. However, system noises such as pupil aberrations, LEDs misalignment and so on, are inevitably introduced in the process of capturing low-resolution images. To address this problem, we propose a new method to insert the Group-based sparse representation (GSR) into the convergence-related metric of FPM as the regularization term in this paper. We have carried out the experiments over both synthetic and real captured images, and the results demonstrate that the proposed method is able to have promising performance while inhibiting the noises efficiently.

  9. Urdu character recognition using fourier descriptors for optical networks

    Science.gov (United States)

    Lodhi, S. M.; Matin, M. A.

    2005-08-01

    This work deals with the problem of recognition of Urdu characters using Fourier descriptors for optical networks. In particular, the scope of this work has been to develop a robust Urdu characters pattern classification, representation, and recognition system, which can classify patterns even if they are deformed by transformations like rotation, scaling, and translation or any combination of these, in the presence of noise. Fourier descriptors are used to uniquely describe, classify, and recognize Urdu characters within one sub-class, that provide a remarkably simple way to draw definite conclusions from vague, ambiguous, noisy or imprecise information. Although current information transmission media i.e. cable, Ethernet etc. may still be used for communications but we proposed new technology i.e. WDM (Wavelength Division Multiplexing) due to its high speed and low loss transmission. Finally experimental results are presented to show the power and robustness of the proposed technique for Urdu character recognition.

  10. Quantum arithmetic with the quantum Fourier transform

    Science.gov (United States)

    Ruiz-Perez, Lidia; Garcia-Escartin, Juan Carlos

    2017-06-01

    The quantum Fourier transform offers an interesting way to perform arithmetic operations on a quantum computer. We review existing quantum Fourier transform adders and multipliers and comment some simple variations that extend their capabilities. These modified circuits can perform modular and non-modular arithmetic operations and work with signed integers. Among the operations, we discuss a quantum method to compute the weighted average of a series of inputs in the transform domain. One of the circuits, the controlled weighted sum, can be interpreted as a circuit to compute the inner product of two data vectors.

  11. Fourier analysis in several complex variables

    CERN Document Server

    Ehrenpreis, Leon

    2006-01-01

    Suitable for advanced undergraduates and graduate students, this text develops comparison theorems to establish the fundamentals of Fourier analysis and to illustrate their applications to partial differential equations.The three-part treatment begins by establishing the quotient structure theorem or fundamental principle of Fourier analysis. Topics include the geometric structure of ideals and modules, quantitative estimates, and examples in which the theory can be applied. The second part focuses on applications to partial differential equations and covers the solution of homogeneous and inh

  12. Fourier transforms and convolutions for the experimentalist

    CERN Document Server

    Jennison, RC

    1961-01-01

    Fourier Transforms and Convolutions for the Experimentalist provides the experimentalist with a guide to the principles and practical uses of the Fourier transformation. It aims to bridge the gap between the more abstract account of a purely mathematical approach and the rule of thumb calculation and intuition of the practical worker. The monograph springs from a lecture course which the author has given in recent years and for which he has drawn upon a number of sources, including a set of notes compiled by the late Dr. I. C. Browne from a series of lectures given by Mr. J . A. Ratcliffe of t

  13. Fourier Analysis of the BTZ Black Hole

    OpenAIRE

    Tolfree, Ian M.

    2009-01-01

    In this paper we extend our previous work regarding the role of the Fourier transformation in bulk to boundary mappings to include the BTZ black hole. We follow standard procedures for modifying Fourier Transformations to accommodate quotient spaces and arrive at a bulk to boundary mapping in a black hole background. We show that this mapping is consistent with known results and lends a new insight into the AdS/CFT duality. We find that the micro-states corresponding to the entropy of a bulk ...

  14. Electro-optic imaging Fourier transform spectrometer

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Znod, Hanying (Inventor)

    2009-01-01

    An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.

  15. Implementation of quantum and classical discrete fractional Fourier transforms

    Science.gov (United States)

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N.; Szameit, Alexander

    2016-01-01

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools. PMID:27006089

  16. Implementation of quantum and classical discrete fractional Fourier transforms.

    Science.gov (United States)

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N; Szameit, Alexander

    2016-03-23

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools.

  17. Implementation of quantum and classical discrete fractional Fourier transforms

    Science.gov (United States)

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N.; Szameit, Alexander

    2016-03-01

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools.

  18. An optical Fourier transform coprocessor with direct phase determination.

    Science.gov (United States)

    Macfaden, Alexander J; Gordon, George S D; Wilkinson, Timothy D

    2017-10-20

    The Fourier transform is a ubiquitous mathematical operation which arises naturally in optics. We propose and demonstrate a practical method to optically evaluate a complex-to-complex discrete Fourier transform. By implementing the Fourier transform optically we can overcome the limiting O(nlogn) complexity of fast Fourier transform algorithms. Efficiently extracting the phase from the well-known optical Fourier transform is challenging. By appropriately decomposing the input and exploiting symmetries of the Fourier transform we are able to determine the phase directly from straightforward intensity measurements, creating an optical Fourier transform with O(n) apparent complexity. Performing larger optical Fourier transforms requires higher resolution spatial light modulators, but the execution time remains unchanged. This method could unlock the potential of the optical Fourier transform to permit 2D complex-to-complex discrete Fourier transforms with a performance that is currently untenable, with applications across information processing and computational physics.

  19. Potential landscape and flux field theory for turbulence and nonequilibrium fluid systems

    Science.gov (United States)

    Wu, Wei; Zhang, Feng; Wang, Jin

    2018-02-01

    Turbulence is a paradigm for far-from-equilibrium systems without time reversal symmetry. To capture the nonequilibrium irreversible nature of turbulence and investigate its implications, we develop a potential landscape and flux field theory for turbulent flow and more general nonequilibrium fluid systems governed by stochastic Navier-Stokes equations. We find that equilibrium fluid systems with time reversibility are characterized by a detailed balance constraint that quantifies the detailed balance condition. In nonequilibrium fluid systems with nonequilibrium steady states, detailed balance breaking leads directly to a pair of interconnected consequences, namely, the non-Gaussian potential landscape and the irreversible probability flux, forming a 'nonequilibrium trinity'. The nonequilibrium trinity characterizes the nonequilibrium irreversible essence of fluid systems with intrinsic time irreversibility and is manifested in various aspects of these systems. The nonequilibrium stochastic dynamics of fluid systems including turbulence with detailed balance breaking is shown to be driven by both the non-Gaussian potential landscape gradient and the irreversible probability flux, together with the reversible convective force and the stochastic stirring force. We reveal an underlying connection of the energy flux essential for turbulence energy cascade to the irreversible probability flux and the non-Gaussian potential landscape generated by detailed balance breaking. Using the energy flux as a center of connection, we demonstrate that the four-fifths law in fully developed turbulence is a consequence and reflection of the nonequilibrium trinity. We also show how the nonequilibrium trinity can affect the scaling laws in turbulence.

  20. Multi-Scale Microstructural Thermoelectric Materials: Transport Behavior, Non-Equilibrium Preparation, and Applications.

    Science.gov (United States)

    Su, Xianli; Wei, Ping; Li, Han; Liu, Wei; Yan, Yonggao; Li, Peng; Su, Chuqi; Xie, Changjun; Zhao, Wenyu; Zhai, Pengcheng; Zhang, Qingjie; Tang, Xinfeng; Uher, Ctirad

    2017-05-01

    Considering only about one third of the world's energy consumption is effectively utilized for functional uses, and the remaining is dissipated as waste heat, thermoelectric (TE) materials, which offer a direct and clean thermal-to-electric conversion pathway, have generated a tremendous worldwide interest. The last two decades have witnessed a remarkable development in TE materials. This Review summarizes the efforts devoted to the study of non-equilibrium synthesis of TE materials with multi-scale structures, their transport behavior, and areas of applications. Studies that work towards the ultimate goal of developing highly efficient TE materials possessing multi-scale architectures are highlighted, encompassing the optimization of TE performance via engineering the structures with different dimensional aspects spanning from the atomic and molecular scales, to nanometer sizes, and to the mesoscale. In consideration of the practical applications of high-performance TE materials, the non-equilibrium approaches offer a fast and controllable fabrication of multi-scale microstructures, and their scale up to industrial-size manufacturing is emphasized here. Finally, the design of two integrated power generating TE systems are described-a solar thermoelectric-photovoltaic hybrid system and a vehicle waste heat harvesting system-that represent perhaps the most important applications of thermoelectricity in the energy conversion area. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Extreme quantum nonequilibrium, nodes, vorticity, drift and relaxation retarding states

    Science.gov (United States)

    Underwood, Nicolas G.

    2018-02-01

    Consideration is given to the behaviour of de Broglie trajectories that are separated from the bulk of the Born distribution with a view to describing the quantum relaxation properties of more ‘extreme’ forms of quantum nonequilibrium. For the 2D isotropic harmonic oscillator, through the construction of what is termed the ‘drift field’, a description is given of a general mechanism that causes the relaxation of ‘extreme’ quantum nonequilibrium. Quantum states are found which do not feature this mechanism, so that relaxation may be severely delayed or possibly may not take place at all. A method by which these states may be identified, classified and calculated is given in terms of the properties of the nodes of the state. Properties of the nodes that enable this classification are described for the first time.

  2. On Equivalence of Nonequilibrium Thermodynamic and Statistical Entropies

    Directory of Open Access Journals (Sweden)

    Purushottam D. Gujrati

    2015-02-01

    Full Text Available We review the concept of nonequilibrium thermodynamic entropy and observables and internal variables as state variables, introduced recently by us, and provide a simple first principle derivation of additive statistical entropy, applicable to all nonequilibrium states by treating thermodynamics as an experimental science. We establish their numerical equivalence in several cases, which includes the most important case when the thermodynamic entropy is a state function. We discuss various interesting aspects of the two entropies and show that the number of microstates in the Boltzmann entropy includes all possible microstates of non-zero probabilities even if the system is trapped in a disjoint component of the microstate space. We show that negative thermodynamic entropy can appear from nonnegative statistical entropy.

  3. A non-equilibrium extension of quantum gravity

    CERN Document Server

    Mandrin, Pierre A

    2016-01-01

    A variety of quantum gravity models (including spin foams) can be described using a path integral formulation. A path integral has a well-known statistical mechanical interpretation in connection with a canonical ensemble. In this sense, a path integral describes the thermodynamic equilibrium of a local system in a thermal bath. This interpretation is in contrast to solutions of Einstein's Equations which depart from local thermodynamical equilibrium (one example is shown explicitly). For this reason, we examine an extension of the path integral model to a (locally) non-equilibrium description. As a non-equilibrium description, we propose to use a global microcanonical ensemble with constraints. The constraints reduce the set of admissible microscopic states to be consistent with the macroscopic geometry. We also analyse the relation between the microcanonical description and a statistical approach not based on dynamical assumptions which has been proposed recently. This analysis is of interest for the test o...

  4. Phase transitions, scaling and renormalisation in nonequilibrium systems

    CERN Document Server

    Hanney, T E

    2002-01-01

    critical fixed point. Extensions to include disorder, to higher dimensions, and to other models are all possible using the method. Using the mapping between the Master equation and the Schroedinger equation in imaginary time, this scaling procedure is rephrased as a new blocking for quantum-spin systems. Existing methods of real space renormalisation for quantum-spin systems are applied to a variety of previously unconsidered exclusion models. In particular, it is shown how such techniques can be applied to models whose dynamics conserve particle number. Finally, by applying a Trotter decomposition to the quantum-spin Hamiltonian, it is shown how a nonequilibrium exclusion model can be written in terms of a classical Hamiltonian for Ising spin variables in one higher dimension. This mapping admits the possibility rescaling time and length scales separately, and with reference to a specific update mechanism. Nonequilibrium phase transitions and critical phenomena in simple lattice-based interacting particle mo...

  5. Geometric phase contribution to quantum nonequilibrium many-body dynamics.

    Science.gov (United States)

    Tomka, Michael; Polkovnikov, Anatoli; Gritsev, Vladimir

    2012-02-24

    We study the influence of geometry of quantum systems underlying space of states on its quantum many-body dynamics. We observe an interplay between dynamical and topological ingredients of quantum nonequilibrium dynamics revealed by the geometrical structure of the quantum space of states. As a primary example we use the anisotropic XY ring in a transverse magnetic field with an additional time-dependent flux. In particular, if the flux insertion is slow, nonadiabatic transitions in the dynamics are dominated by the dynamical phase. In the opposite limit geometric phase strongly affects transition probabilities. This interplay can lead to a nonequilibrium phase transition between these two regimes. We also analyze the effect of geometric phase on defect generation during crossing a quantum-critical point.

  6. Phase transition universality classes of classical, nonequilibrium systems

    CERN Document Server

    Ódor, G

    2004-01-01

    In the first chapter I summarize the most important critical exponents and relations used in this work. In the second chapter I briefly address the question of scaling behavior at first order phase transitions.In chapter three I review dynamical extensions of basic static classes, show the effect of mixing dynamics and percolation behavior. The main body of this work is given in chapter four where genuine, dynamical universality classes specific to nonequilibrium systems are introduced. In chapter five I continue overviewing such nonequilibrium classes but in coupled, multi-component systems. Most of known transitions in low dimensional systems are between active and absorbing states of reaction-diffusion type systems, but I briefly introduce related classes that appear in interface growth models in chapter six. Some of them are related to critical behavior of coupled, multi-component systems. Finally in chapter seven I summarize families of absorbing state system classes, mean-field classes and the most freq...

  7. Minimum energetic cost to maintain a target nonequilibrium state

    Science.gov (United States)

    Horowitz, Jordan M.; Zhou, Kevin; England, Jeremy L.

    2017-04-01

    In the absence of external driving, a system exposed to thermal fluctuations will relax to equilibrium. However, the constant input of work makes it possible to counteract this relaxation and maintain the system in a nonequilibrium steady state. In this article, we use the stochastic thermodynamics of Markov jump processes to compute the minimum rate at which energy must be supplied and dissipated to maintain an arbitrary nonequilibrium distribution in a given energy landscape. This lower bound depends on two factors: the undriven probability current in the equilibrium state and the distance from thermal equilibrium of the target distribution. By showing the consequences of this result in a few simple examples, we suggest general implications for the required energetic costs of macromolecular repair and cytosolic protein localization.

  8. Non-equilibrium statistical physics with application to disordered systems

    CERN Document Server

    Cáceres, Manuel Osvaldo

    2017-01-01

    This textbook is the result of the enhancement of several courses on non-equilibrium statistics, stochastic processes, stochastic differential equations, anomalous diffusion and disorder. The target audience includes students of physics, mathematics, biology, chemistry, and engineering at undergraduate and graduate level with a grasp of the basic elements of mathematics and physics of the fourth year of a typical undergraduate course. The little-known physical and mathematical concepts are described in sections and specific exercises throughout the text, as well as in appendices. Physical-mathematical motivation is the main driving force for the development of this text. It presents the academic topics of probability theory and stochastic processes as well as new educational aspects in the presentation of non-equilibrium statistical theory and stochastic differential equations.. In particular it discusses the problem of irreversibility in that context and the dynamics of Fokker-Planck. An introduction on fluc...

  9. Density-functional method for nonequilibrium electron transport

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Mozos, J.L.; Ordejon, P.

    2002-01-01

    We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density-functional theory (DFT) as implemented...... the contact and the electrodes on the same footing. The effect of the finite bias (including self-consistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme...... wires connected to aluminum electrodes with extended or finite cross section, (ii) single atom gold wires, and finally (iii) large carbon nanotube systems with point defects....

  10. Superconductors in non-equilibrium. Higgs oscillations and induced superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Nikolaj; Schnyder, Andreas; Manske, Dirk [Max-Planck-Institut fuer Festkoerperforschung, D-70569 Stuttgart (Germany); Krull, Holger [Max-Planck-Institut fuer Festkoerperforschung, D-70569 Stuttgart (Germany); Lehrstuhl fuer Theoretische Physik, Technische Universitaet Dortmund, D-44221 Dortmund (Germany); Tohyama, Takami [Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585 (Japan)

    2016-07-01

    Nonequilibrium pump-probe time-domain spectroscopy opens new perspectives in studying the dynamical properties of the strongly correlated electron systems. In particular, new effects, such as transient superconductivity or Higgs oscillations of the superconducting condensate, can be obtained. Using various methods we present a theoretical study of the nonequilibrium dynamics in superconductors. Firstly, within the framework of the density matrix formalism we study Higgs oscillations in superconductors, which allow to detect the properties of the superconducting condensate as a function of time. For two-band superconductors the interplay between the phase (Leggett) and amplitude (Higgs) modes is analyzed in detail and new predictions are made. Secondly, employing the time-dependent Lanczos algorithm to the one-dimensional extended Hubbard model we observe appearance of a transient Meissner effect, which is a fingerprint of the induced superconductivity.

  11. Simulations of a molecular plasma in collisional-radiative nonequilibrium

    Science.gov (United States)

    Cambier, Jean-Luc; Moreau, Stephane

    1993-01-01

    A code for the simulation of nonequilibrium plasmas is being developed, with the capability to couple the plasma fluid-dynamics for a single fluid with a collisional-radiative model, where electronic states are treated as separate species. The model allows for non-Boltzmann distribution of the electronic states. Deviations from the Boltzmann distributions are expected to occur in the rapidly ionizing regime behind a strong shock or in the recombining regime during a fast expansion. This additional step in modeling complexity is expected to yield more accurate predictions of the nonequilibrium state and the radiation spectrum and intensity. An attempt at extending the code to molecular plasma flows is presented. The numerical techniques used, the thermochemical model, and the results of some numerical tests are described.

  12. Investigation of Non-Equilibrium Radiation for Earth Entry

    Science.gov (United States)

    Brandis, A. M.; Johnston, C. O.; Cruden, B. A.

    2016-01-01

    For Earth re-entry at velocities between 8 and 11.5 km/s, the accuracy of NASA's computational uid dynamic and radiative simulations of non-equilibrium shock layer radiation is assessed through comparisons with measurements. These measurements were obtained in the NASA Ames Research Center's Electric Arc Shock Tube (EAST) facility. The experiments were aimed at measuring the spatially and spectrally resolved radiance at relevant entry conditions for both an approximate Earth atmosphere (79% N2 : 21% O2 by mole) as well as a more accurate composition featuring the trace species Ar and CO2 (78.08% N2 : 20.95% O2 : 0.04% CO2 : 0.93% Ar by mole). The experiments were configured to target a wide range of conditions, of which shots from 8 to 11.5 km/s at 0.2 Torr (26.7 Pa) are examined in this paper. The non-equilibrium component was chosen to be the focus of this study as it can account for a significant percentage of the emitted radiation for Earth re-entry, and more importantly, non-equilibrium has traditionally been assigned a large uncertainty for vehicle design. The main goals of this study are to present the shock tube data in the form of a non-equilibrium metric, evaluate the level of agreement between the experiment and simulations, identify key discrepancies and to examine critical aspects of modeling non-equilibrium radiating flows. Radiance pro les integrated over discreet wavelength regions, ranging from the Vacuum Ultra Violet (VUV) through to the Near Infra-Red (NIR), were compared in order to maximize both the spectral coverage and the number of experiments that could be used in the analysis. A previously defined non-equilibrium metric has been used to allow comparisons with several shots and reveal trends in the data. Overall, LAURA/HARA is shown to under-predict EAST by as much as 40% and over-predict by as much as 12% depending on the shock speed. DPLR/NEQAIR is shown to under-predict EAST by as much as 50% and over-predict by as much as 20% depending

  13. All-optical signal processing of OTDM and OFDM signals based on time-domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Clausen, Anders; Guan, Pengyu; Mulvad, Hans Christian Hansen

    2014-01-01

    All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented.......All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented....

  14. Non-equilibrium thermal entanglement for a three spin chain

    Science.gov (United States)

    Pumulo, N.; Sinayskiy, I.; Petruccione, F.

    2011-08-01

    The dynamics of a chain of three spins coupled at both ends to separate bosonic baths at different temperatures is studied. An exact analytical solution of the master equation in the Born-Markov approximation for the reduced density matrix of the chain is constructed. It is shown that for long times the reduced density matrix converges to the non-equilibrium steady state. Dynamical and steady state properties of the concurrence between the first and the last spin are studied.

  15. Effect of nonequilibrium quasiparticle flow on SNS Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Kaplunenko, V.K.; Ryazanov, V.V.; Shmidt, V.V.

    1985-10-01

    Experiments have been carried out on the effect of a nonequilibrium flow of quasiparticles on the Josephson properties of a Ta-Cu-Ta SNS junction. A nonequilibrium quasiparticle flow can be set up at the junction because the thickness of the superconducting banks of the SNS sandwich is on the order of the depth to which the longitudinal electric field penetrates into the superconductor, and the sandwich is bracketed by thick plates of a normal metal. During the injection of quasiparticles into one of the superconducting banks of the SNS junction, Josephson generation is excited at the junction; the total current flowing across the junction is zero. The nonequilibrium quasiparticle current which flows across the SNS junction is several times the critical current I/sub c/ and has no direct effect on its Josephson characteristics. The appearance of a difference in the electrochemical potentials of the pairs and of Josephson generation at the junction is due exclusively to the flow of the superconducting current. The experimental results are analyzed on the basis of an equivalent circuit proposed for the junction by Kadin, Smith, and Skocpol (J. Low Temp. Phys. 38, 497 (1980)), simplified somewhat for the case at hand. A study of the temperature dependence of the effects shows that at T> or =0.97T/sub c/ the nonequilibrium quasiparticle current in the normal Josephson intermediate layer of the junction does not depend on Andreev reflection processes at the NS interfaces. The scale time for electron-phonon energy relaxation in the tantalum used as the superconductor is estimated to be tau/sub Epsilon/roughly-equal 4.0 x 10/sup -1/ s.

  16. Non-Equilibrium Modeling of Inductively Coupled RF Plasmas

    Science.gov (United States)

    2015-01-01

    line with squares r = 0.04m, line with triangles r = 0.08m [wall]). On the other hand the free-electron temperature in- creases, reaches a maximum and...circles), in the mid- point of the torch (squares) and at the wall ( triangles ) at different pressures. The population distributions exhibit significant...De Pascale , P. Diomede, F. Esposito, C. Gorse, K. Hassouni, A. Laricchiuta, S. Longo, D. Pagano, D. Pietanza, and M. Rutigliano. Non-equilibrium

  17. Non-equilibrium dynamic of a Universe formation

    Science.gov (United States)

    Lev, S. B.; Lev, B. I.

    2017-09-01

    A new stochastic model of dynamic of Universe formation is presented. This model takes into account the interaction of fundamental scalar field with possible multiplicative noise fluctuations of other nature. The noise-induced model of the Universe formation presented in this paper allows to describe its inflationary expansion till the present time. Such expansion can be explained in presented model if one takes into account the non-equilibrium dynamic of a transition into a new stable state.

  18. Non-equilibrium mechanics and dynamics of motor activated gels

    OpenAIRE

    MacKintosh, Fred C.; Levine, Alex J.

    2007-01-01

    The mechanics of cells is strongly affected by molecular motors that generate forces in the cellular cytoskeleton. We develop a model for cytoskeletal networks driven out of equilibrium by molecular motors exerting transient contractile stresses. Using this model we show how motor activity can dramatically increase the network's bulk elastic moduli. We also show how motor binding kinetics naturally leads to enhanced low-frequency stress fluctuations that result in non-equilibrium diffusive mo...

  19. Nonequilibrium potential and fluctuation theorems for quantum maps.

    Science.gov (United States)

    Manzano, Gonzalo; Horowitz, Jordan M; Parrondo, Juan M R

    2015-09-01

    We derive a general fluctuation theorem for quantum maps. The theorem applies to a broad class of quantum dynamics, such as unitary evolution, decoherence, thermalization, and other types of evolution for quantum open systems. The theorem reproduces well-known fluctuation theorems in a single and simplified framework and extends the Hatano-Sasa theorem to quantum nonequilibrium processes. Moreover, it helps to elucidate the physical nature of the environment that induces a given dynamics in an open quantum system.

  20. Molecular-Based Optical Diagnostics for Hypersonic Nonequilibrium Flows

    Science.gov (United States)

    Danehy, Paul; Bathel, Brett; Johansen, Craig; Winter, Michael; O'Byrne, Sean; Cutler, Andrew

    2015-01-01

    This presentation package consists of seven different talks rolled up into one. These talks are all invited orals presentations in a special session at the Aviation 2015 conference and represent contributions that were made to a recent AIAA book that will be published entitled 'Hypersonic Nonequilibrium Flows: Fundamentals and Recent Advances'. Slide 5 lists the individual presentations that will be given during the special session.

  1. Nonequilibrium Energetics of a Single F1-ATPase Molecule

    OpenAIRE

    Toyabe, Shoichi; Watanabe-Nakayama, Takahiro; Okamoto, Tetsuaki; Kudo, Seishi; Muneyuki, Eiro

    2010-01-01

    Molecular motors drive mechanical motions utilizing the free energy liberated from chemical reactions such as ATP hydrolysis. Although it is essential to know the efficiency of this free energy transduction, it has been a challenge due to the system's microscopic scale. Here, we evaluate the single-molecule energetics of a rotary molecular motor, F1-ATPase, by applying a recently derived nonequilibrium equality together with an electrorotation method. We show that the sum of the heat flow thr...

  2. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Science.gov (United States)

    Raz, O.; Subaşı, Y.; Jarzynski, C.

    2016-04-01

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP)—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  3. Crossover from Nonequilibrium Fractal Growth to Equilibrium Compact Growth

    DEFF Research Database (Denmark)

    Sørensen, Erik Schwartz; Fogedby, Hans C.; Mouritsen, Ole G.

    1988-01-01

    Solidification controlled by vacancy diffusion is studied by Monte Carlo simulations of a two-dimensional Ising model defined by a Hamiltonian which models a thermally driven fluid-solid phase transition. The nonequilibrium morphology of the growing solid is studied as a function of time as the s...... as the system relaxes into equilibrium described by a temperature. At low temperatures the model exhibits fractal growth at early times and crossover to compact solidification as equilibrium is approached....

  4. THE EFFECT OF AMBIENT DISSOCIATION ON NONEQUILIBRIUM SHOCK LAYERS.

    Science.gov (United States)

    The effects of ambient dissociation in a hypersonic free stream were examined for inviscid, nonequilibrium shock layers. The profiles of atom...enthalpy and for fixed flight speed. For fixed enthalpy, the effect of ambient dissociation was shown to decay rapidly behind the shock. For fixed...flight speed, the correlation was expressed by a simple subtraction of the ambient dissociation fraction. The subtraction rule preserves the gas

  5. Simple Fabrication of Micromixer Based on Non-Equilibrium Electrokinetics in Micro/Nano Hybrid Fluidic System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Samuel; Kim, Sun Min [Inha University, Incheon (Korea, Republic of)

    2011-04-15

    In this study, we developed a micromixer based on the non-equilibrium electrokinetics at the junction of a microchannel and nanochannel. Two fluid streams were mixed by an electro-osmotic flow and a vortex flow created as a result of the non-equilibrium electrokinetics at the junction of the microchannel and nanochannel. Initially, the microchannel was fabricated using Polydimethylsiloxane (PDMS) by the general soft lithography process and the nanochannel was created at a specific position on the microchannel by applying a high voltage. To evaluate the mixing performance of the micromixer, fluorescent distribution was analyzed by using the fluorescent dye, Rhodamine B. About 90% mixing was achieved with this novel micromixer, and this micromixer can be used in microsystems for biochemical sample analysis.

  6. Precise determination of the nonequilibrium tricritical point based on Lynden-Bell theory in the Hamiltonian mean-field model.

    Science.gov (United States)

    Ogawa, Shun; Yamaguchi, Yoshiyuki Y

    2011-12-01

    Existence of a nonequilibrium tricritical point has been revealed in the Hamiltonian mean-field model by a nonequilibrium statistical mechanics. This statistical mechanics gives a distribution function containing unknown parameters, and the parameters are determined by solving simultaneous equations depending on a given initial state. Due to difficulty in solving these equations, pointwise numerical detection of the tricritical point has been unavoidable on a plane characterizing a family of initial states. In order to look into the tricritical point, we expand the simultaneous equations with respect to the order parameter and reduce them to one algebraic equation. The tricritical point is precisely identified by analyzing coefficients of the reduced equation. Reentrance to an ordered phase in a high-energy region is revisited around the obtained tricritical point.

  7. Steady bipartite coherence induced by non-equilibrium environment

    Science.gov (United States)

    Huangfu, Yong; Jing, Jun

    2018-01-01

    We study the steady state of two coupled two-level atoms interacting with a non-equilibrium environment that consists of two heat baths at different temperatures. Specifically, we analyze four cases with respect to the configuration about the interactions between atoms and heat baths. Using secular approximation, the conventional master equation usually neglects steady-state coherence, even when the system is coupled with a non-equilibrium environment. When employing the master equation with no secular approximation, we find that the system coherence in our model, denoted by the off-diagonal terms in the reduced density matrix spanned by the eigenvectors of the system Hamiltonian, would survive after a long-time decoherence evolution. The absolute value of residual coherence in the system relies on different configurations of interaction channels between the system and the heat baths. We find that a large steady quantum coherence term can be achieved when the two atoms are resonant. The absolute value of quantum coherence decreases in the presence of additional atom-bath interaction channels. Our work sheds new light on the mechanism of steady-state coherence in microscopic quantum systems in non-equilibrium environments.

  8. A porous flow approach to model thermal non-equilibrium applicable to melt migration

    Science.gov (United States)

    Schmeling, Harro; Marquart, Gabriele; Grebe, Michael

    2018-01-01

    We develop an approach for heat exchange between a fluid and a solid phase of a porous medium where the temperatures of the fluid and matrix are not in thermal equilibrium. The formulation considers moving of the fluid within a resting or deforming porous matrix in an Eulerian coordinate system. The approach can be applied, for example, to partially molten systems or to brine transport in porous rocks. We start from an existing theory for heat exchange where the energy conservation equations for the fluid and the solid phases are separated and coupled by a heat exchange term. This term is extended to account for the full history of heat exchange. It depends on the microscopic geometry of the fluid phase. For the case of solid containing hot, fluid-filled channels, we derive an expression based on a time-dependent Fourier approach for periodic half-waves. On the macroscopic scale, the temporal evolution of the heat exchange leads to a convolution integral along the flow path of the solid, which simplifies considerably in case of a resting matrix. The evolution of the temperature in both phases with time is derived by inserting the heat exchange term into the energy equations. We explore the effects of thermal non-equilibrium between fluid and solid by considering simple cases with sudden temperature differences between fluid and solid as initial or boundary conditions, and by varying the fluid velocity with respect to the resting porous solid. Our results agree well with an analytical solution for non-moving fluid and solid. The temperature difference between solid and fluid depends on the Peclet number based on the Darcy velocity. For Peclet numbers larger than 1, the temperature difference after one diffusion time reaches 5 per cent of \\tilde{T} or more (\\tilde{T} is a scaling temperature, e.g. the initial temperature difference). Thus, our results imply that thermal non-equilibrium can play an important role for melt migration through partially molten systems

  9. Improving spatial resolution of the light field microscope with Fourier ptychography

    Science.gov (United States)

    Tani, Yoshitake; Usuki, Shin; Miura, Kenjiro T.

    2017-09-01

    Light field microscope (LFM) is an optical microscope capable of obtaining images having large depth of field with different viewpoints. By using the parallax of these multi-view images, it is possible to reconstruct the 3D sample. However, the sampling interval of this multi-viewpoint image depends on the pitch interval of the microlens array, so the spatial resolution is low, and the accuracy of the 3D sample to be reconstructed is also low. Conventional research has a method of increasing the spatial resolution by subpixel-shifted multiple images. However, this method has problems such as the necessity of mechanical operation and high cost. Therefore, we propose applying Fourier ptychography to the LFM. Fourier ptychography is a technique to obtain high spatial resolution images by joining images obtained by irradiating samples from different angles using LED arrays in Fourier space. Fourier ptychography does not require mechanical scanning and is high throughput and low cost. In addition, Fourier ptycoography is possible to obtain phase information on a sample, and it is also possible to obtain a fine 3D sample. We propose a method to generate high spatial resolution multiview images using Fourier ptychography and reconstruct highly accurate 3D sample from those images. In this research, we experiment with the original LFM and verify the effect.

  10. Fourier phase demodulation of interferometric fiber sensor

    Science.gov (United States)

    Fu, Xin; Lu, Ping; Liu, Deming; Zhang, Jiangshan

    2017-10-01

    A novel demodulation method for interferometric fiber sensor is proposed in this paper. The physical parameters to be measured by the sensor is obtained by calculating the phase variation of the interference components. The phase variation is computed with the assist of the fast Fourier analysis. For fiber interferometers, most of the energy is contained in the few spatial frequencies corresponding to the components that produce the interference. Therefore, the information of the interference fringe can be presented by the Fourier results at those intrinsic frequencies. Based on this assumption, we proposed a novel method to interrogate the fiber interferometer by calculating the Fourier phase at the spatial frequency. Theoretical derivation proves that the Fourier phase variation is equal to the phase change of the interferometer. Simulation results demonstrate the ability of noise resistance of the proposed method since the information of all wavelength sampling points are adopted for the demodulation process. A Sagnac interferometer based on a section of polarization-maintaining photonic crystal fiber is utilized to verify the feasibility of the phase demodulation technique by lateral pressure sensing. Experimental results of -0.069rad/kPa is acquired.

  11. Fourier inversion on a reductive symmetric space

    NARCIS (Netherlands)

    Ban, E.P. van den

    1999-01-01

    Let X be a semisimple symmetric space. In previous papers, [8] and [9], we have dened an explicit Fourier transform for X and shown that this transform is injective on the space C 1 c (X) ofcompactly supported smooth functions on X. In the present paper, which is a continuation of these papers, we

  12. Classical versus complex fractional Fourier transformation.

    Science.gov (United States)

    Dragoman, D

    2009-02-01

    The quantum optical complex fractional Fourier transform (FRFT) has been related to the classical FRFT using both classical and quantum formalisms. In particular, it was shown that the kernel of the complex FRFT can be classically produced with rotated astigmatic optical systems that mimic the quantum entanglement property.

  13. Bernoulli Polynomials, Fourier Series and Zeta Numbers

    DEFF Research Database (Denmark)

    Scheufens, Ernst E

    2013-01-01

    Fourier series for Bernoulli polynomials are used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent...

  14. A Fourier analysis of extremal events

    DEFF Research Database (Denmark)

    Zhao, Yuwei

    is the extremal periodogram. The extremal periodogram shares numerous asymptotic properties with the periodogram of a linear process in classical time series analysis: the asymptotic distribution of the periodogram ordinates at the Fourier frequencies have a similar form and smoothed versions of the periodogram...

  15. Euler Polynomials, Fourier Series and Zeta Numbers

    DEFF Research Database (Denmark)

    Scheufens, Ernst E

    2012-01-01

    Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....

  16. Fourier Multiplier Theorems Involving Type and Cotype

    NARCIS (Netherlands)

    Rozendaal, J.; Veraar, M.C.

    2017-01-01

    In this paper we develop the theory of Fourier multiplier operators (Formula presented.), for Banach spaces X and Y, (Formula presented.) and (Formula presented.) an operator-valued symbol. The case (Formula presented.) has been studied extensively since the 1980s, but far less is known for

  17. The periodogram at the Fourier frequencies

    NARCIS (Netherlands)

    Kokoszka, P; Mikosch, T

    In the time series literature one can often find the claim that the periodogram ordinates of an lid sequence at the Fourier frequencies behave like an lid standard exponential sequence. We review some results about functions of these periodogram ordinates, including the convergence of extremes,

  18. Fourier Series Formalization in ACL2(r

    Directory of Open Access Journals (Sweden)

    Cuong K. Chau

    2015-09-01

    Full Text Available We formalize some basic properties of Fourier series in the logic of ACL2(r, which is a variant of ACL2 that supports reasoning about the real and complex numbers by way of non-standard analysis. More specifically, we extend a framework for formally evaluating definite integrals of real-valued, continuous functions using the Second Fundamental Theorem of Calculus. Our extended framework is also applied to functions containing free arguments. Using this framework, we are able to prove the orthogonality relationships between trigonometric functions, which are the essential properties in Fourier series analysis. The sum rule for definite integrals of indexed sums is also formalized by applying the extended framework along with the First Fundamental Theorem of Calculus and the sum rule for differentiation. The Fourier coefficient formulas of periodic functions are then formalized from the orthogonality relations and the sum rule for integration. Consequently, the uniqueness of Fourier sums is a straightforward corollary. We also present our formalization of the sum rule for definite integrals of infinite series in ACL2(r. Part of this task is to prove the Dini Uniform Convergence Theorem and the continuity of a limit function under certain conditions. A key technique in our proofs of these theorems is to apply the overspill principle from non-standard analysis.

  19. Liquid chromatography-Fourier-transform infrared spectrometry.

    NARCIS (Netherlands)

    Gooijer, C.; Brinkman, U.A.T.; Somsen, G.W.

    1999-01-01

    Over the past years the coupling of liquid chromatography (LC) and Fourier-transform infrared spectrometry (FT-IR) has been pursued primarily to achieve specific detection and/or identification of sample constituents. Two approaches can be discerned in the combination of LC and FT-IR. The first and

  20. Liquid chromatography-Fourier-transform infrared spectrometry

    NARCIS (Netherlands)

    Somsen, G.W; Gooijer, C; Brinkman, U.A Th

    1999-01-01

    Over the past years the coupling of liquid chromatography (LC) and Fourier-transform infrared spectrometry (FT-IR) has been pursued primarily to achieve specific detection and/or identification of sample constituents. Two approaches can be discerned in the combination of LC and FT-IR. The first and

  1. Fourier Series The Mathematics of Periodic Phenomena

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 10. Fourier Series The Mathematics of Periodic Phenomena. S Thangavelu ... Author Affiliations. S Thangavelu1. Department of Mathematics and Statistics, University of New Mexico, Humanities Building 419, Albuquerque, NM 87131-1141, USA ...

  2. Fourier Series Approximations to J2-Bounded Equatorial Orbits

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available The current paper offers a comprehensive dynamical analysis and Fourier series approximations of J2-bounded equatorial orbits. The initial conditions of heterogeneous families of J2-perturbed equatorial orbits are determined first. Then the characteristics of two types of J2-bounded orbits, namely, pseudo-elliptic orbit and critical circular orbit, are studied. Due to the ambiguity of the closed-form solutions which comprise the elliptic integrals and Jacobian elliptic functions, showing little physical insight into the problem, a new scheme, termed Fourier series expansion, is adopted for approximation herein. Based on least-squares fitting to the coefficients, the solutions are expressed with arbitrary high-order Fourier series, since the radius and the flight time vary periodically as a function of the polar angle. As a consequence, the solutions can be written in terms of elementary functions such as cosines, rather than complex mathematical functions. Simulations enhance the proposed approximation method, showing bounded and negligible deviations. The approximation results show a promising prospect in preliminary orbits design, determination, and transfers for low-altitude spacecrafts.

  3. The scale of the Fourier transform: a point of view of the fractional Fourier transform

    Science.gov (United States)

    Jimenez, C. J.; Vilardy, J. M.; Salinas, S.; Mattos, L.; Torres, C. O.

    2017-01-01

    In this paper using the Fourier transform of order fractional, the ray transfer matrix for the symmetrical optical systems type ABCD and the formulae by Collins for the diffraction, we obtain explicitly the expression for scaled Fourier transform conventional; this result is the great importance in optical signal processing because it offers the possibility of scaling the size of output the Fourier distribution of the system, only by manipulating the distance of the diffraction object toward the thin lens, this research also emphasizes on practical limits when a finite spherical converging lens aperture is used. Digital simulation was carried out using the numerical platform of Matlab 7.1.

  4. Atomistic Simulation of Non-Equilibrium Phenomena in Hypersonic Flows

    Science.gov (United States)

    Norman, Paul Erik

    The goal of this work is to model the heterogeneous recombination of atomic oxygen on silica surfaces, which is of interest for accurately predicting the heating on vehicles traveling at hypersonic speeds. This is accomplished by creating a finite rate catalytic model, which describes recombination with a set of elementary gas-surface reactions. Fundamental to a description of surface catalytic reactions are the in situ chemical structures on the surface where recombination can occur. Using molecular dynamics simulations with the Reax GSISiO potential, we find that the chemical sites active in direct gas-phase reactions on silica surfaces consist of a small number of specific structures (or defects). The existence of these defects on real silica surfaces is supported by experimental results and the structure and energetics of these defects have been verified with quantum chemical calculations. The reactions in the finite rate catalytic model are based on the interaction of molecular and atomic oxygen with these defects. Trajectory calculations are used to find the parameters in the forward rate equations, while a combination of detailed balance and transition state theory are used to find the parameters in the reverse rate equations. The rate model predicts that the oxygen recombination coefficient is relatively constant at T (300-1000 K), in agreement with experimental results. At T > 1000 K the rate model predicts a drop off in the oxygen recombination coefficient, in disagreement with experimental results, which predict that the oxygen recombination coefficient increases with temperature. A discussion of the possible reasons for this disagreement, including non-adiabatic collision dynamics, variable surface site concentrations, and additional recombination mechanisms is presented. This thesis also describes atomistic simulations with Classical Trajectory Calculation Direction Simulation Monte Carlo (CTC-DSMC), a particle based method for modeling non-equilibrium

  5. Pulse-induced nonequilibrium dynamics of acetylene inside carbon nanotube studied by an ab initio approach.

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Zhang, Hong; Rubio, Angel

    2012-06-05

    Nanoscale molecular confinement substantially modifies the functionality and electronic properties of encapsulated molecules. Many works have approached this problem from the perspective of quantifying ground-state molecular changes, but little is known about the nonequilibrium dynamics of encapsulated molecular system. In this letter, we report an analysis of the nonequilibrium dynamics of acetylene (C(2)H(2)) inside a semiconducting carbon nanotube (CNT). An ultrashort high-intense laser pulse (2 fs width and 10(15) W/cm(2) intensity) brings the systems out of equilibrium. This process is modeled by comprehensive first-principles time-dependent density-functional simulations. When encapsulated, acetylene dimer, unlike a single acetylene molecule, exhibits correlated vibrational dynamics (C-C bond rotation and H-C-C bending) that is markedly different from the dynamics observed in the gas phase. This result highlights the role of CNT in modulating the optical electric field within the tube. At longer simulation timescales (> 20 fs) in the largest-diameter tube studied here [CNT(14,0)], we observe synchronized rotation about the C-C axes in the dimer and ultimately ejection of one of the four hydrogen atoms. Our results illustrate the richness of photochemical phenomena in confined geometries.

  6. Pulse-induced nonequilibrium dynamics of acetylene inside carbon nanotube studied by an ab initio approach

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Zhang, Hong; Rubio, Angel

    2012-01-01

    Nanoscale molecular confinement substantially modifies the functionality and electronic properties of encapsulated molecules. Many works have approached this problem from the perspective of quantifying ground-state molecular changes, but little is known about the nonequilibrium dynamics of encapsulated molecular system. In this letter, we report an analysis of the nonequilibrium dynamics of acetylene (C2H2) inside a semiconducting carbon nanotube (CNT). An ultrashort high-intense laser pulse (2 fs width and 1015 W/cm2 intensity) brings the systems out of equilibrium. This process is modeled by comprehensive first-principles time-dependent density-functional simulations. When encapsulated, acetylene dimer, unlike a single acetylene molecule, exhibits correlated vibrational dynamics (C–C bond rotation and H–C–C bending) that is markedly different from the dynamics observed in the gas phase. This result highlights the role of CNT in modulating the optical electric field within the tube. At longer simulation timescales (> 20 fs) in the largest-diameter tube studied here [CNT(14,0)], we observe synchronized rotation about the C–C axes in the dimer and ultimately ejection of one of the four hydrogen atoms. Our results illustrate the richness of photochemical phenomena in confined geometries. PMID:22615352

  7. Experimental Study of Nonequilibrium Electrodeposition of Nanostructures on Copper and Nickel for Photochemical Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Rajesh K. Shanmugam

    2011-01-01

    Full Text Available To increase the performance of photochemical fuel cells, nonequilibrium electrodeposition has been performed on Cu and Ni to make photosensitive anodes. Processing parameters including electrolyte concentration, and electrode potential were studied using cyclic voltammetry. Scanning electron microscopy (SEM and X-ray Spectroscopy (EDS were performed to understand the formation of the nanostructures during the nonequilibrium deposition of copper fractals. An increase in the deposition rate was observed with the increase in electrolyte concentration (from 0.05 M to 1.0 M. Similar trend was found when the cathode potential was decreased from −0.5 V to −4.5 V. The effect of substrate material was also examined. Porous fractal structures on copper were achieved, while the deposited material showed high density of surface cracks on nickel. The fractal structures deposited on copper electrode with the increased surface area were converted into copper oxide by oxidation in air. Such oxide samples were made into anodes for photochemical fuel cell application. We demonstrated that an increase in the magnitude of open circuit output voltage is associated with the increase in the fractal surface area under the ultraviolet irradiation test conditions. However, the electrodeposited fractals on nickel showed very limited increase in the magnitude of open circuit voltage.

  8. Giant THz photoconductivity and possible non-equilibrium superconductivity in metallic K3C60

    Science.gov (United States)

    Mitrano, M.; Cantaluppi, A.; Nicoletti, D.; Kaiser, S.; Perucchi, A.; Lupi, S.; Di Pietro, P.; Pontiroli, D.; Riccò, M.; Clark, S. R.; Jaksch, D.; Cavalleri, A.

    2015-01-01

    The non-equilibrium control of emergent phenomena in solids is an important research frontier, encompassing effects like the optical enhancement of superconductivity 1 . Recently, nonlinear excitation 2 , 3 of certain phonons in bilayer cuprates was shown to induce superconducting-like optical properties at temperatures far above Tc 4,5,6. This effect was accompanied by the disruption of competing charge-density-wave correlations7,8, which explained some but not all of the experimental results. Here, we report a similar phenomenon in a very different compound. By exciting metallic K3C60 with mid-infrared optical pulses, we induce a large increase in carrier mobility, accompanied by the opening of a gap in the optical conductivity. Strikingly, these same signatures are observed at equilibrium when cooling metallic K3C60 below the superconducting transition temperature (Tc = 20 K). Although optical techniques alone cannot unequivocally identify non-equilibrium high-temperature superconductivity, we propose this scenario as a possible explanation of our results. PMID:26855424

  9. Path-space variational inference for non-equilibrium coarse-grained systems

    Science.gov (United States)

    Harmandaris, Vagelis; Kalligiannaki, Evangelia; Katsoulakis, Markos; Plecháč, Petr

    2016-06-01

    In this paper we discuss information-theoretic tools for obtaining optimized coarse-grained molecular models for both equilibrium and non-equilibrium molecular simulations. The latter are ubiquitous in physicochemical and biological applications, where they are typically associated with coupling mechanisms, multi-physics and/or boundary conditions. In general the non-equilibrium steady states are not known explicitly as they do not necessarily have a Gibbs structure. The presented approach can compare microscopic behavior of molecular systems to parametric and non-parametric coarse-grained models using the relative entropy between distributions on the path space and setting up a corresponding path-space variational inference problem. The methods can become entirely data-driven when the microscopic dynamics are replaced with corresponding correlated data in the form of time series. Furthermore, we present connections and generalizations of force matching methods in coarse-graining with path-space information methods. We demonstrate the enhanced transferability of information-based parameterizations to different observables, at a specific thermodynamic point, due to information inequalities. We discuss methodological connections between information-based coarse-graining of molecular systems and variational inference methods primarily developed in the machine learning community. However, we note that the work presented here addresses variational inference for correlated time series due to the focus on dynamics. The applicability of the proposed methods is demonstrated on high-dimensional stochastic processes given by overdamped and driven Langevin dynamics of interacting particles.

  10. Ultrafast non-equilibrium carrier dynamics in semiconductor laser mode-locking

    Science.gov (United States)

    Hader, J.; Scheller, M.; Laurain, A.; Kilen, I.; Baker, C.; Moloney, J. V.; Koch, S. W.

    2017-01-01

    Experimental and theoretical results on the mode-locking dynamics in vertical-external-cavity surface-emitting lasers with semiconductor and graphene saturable absorber mirrors are reviewed with an emphasis on the role of nonequilibrium carrier effects. The systems are studied theoretically using a fully microscopic many-body model for the carrier distributions and polarizations, coupled to Maxwell’s equations for the field propagation. Pump-probe measurements are performed with (sub-) 100 fs resolution. The analysis shows that the non-equilibrium carrier dynamics in the gain quantum-wells and saturable absorber medium significantly influences the system’s response and the resulting mode-locked pulses. The microscopic model is used to study the pulse build up from spontaneous emission noise and to determine the dependence of achievable pulse lengths and fluences on the amounts of saturable and non-saturable losses and the optical gain. The change of the group delay dispersion (GDD) on the pump level is examined and the dependence of the pulse lengths on the total amount of GDD is demonstrated experimentally. Theory-experiment comparisons are used to demonstrate the highly quantitative accuracy of the fully microscopic modeling.

  11. Ultrafast Vibrational Dynamics of Water Disentangled by Reverse Nonequilibrium Ab Initio Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Yuki Nagata

    2015-04-01

    Full Text Available Water is a unique solvent with strong, yet highly dynamic, intermolecular interactions. Many insights into this distinctive liquid have been obtained using ultrafast vibrational spectroscopy of water’s O-H stretch vibration. However, it has been challenging to separate the different contributions to the dynamics of the O-H stretch vibration in H_{2}O. Here, we present a novel nonequilibrium molecular dynamics (NEMD algorithm that allows for a detailed picture of water vibrational dynamics by generating nonequilibrium vibrationally excited states at targeted vibrational frequencies. Our ab initio NEMD simulations reproduce the experimentally observed time scales of vibrational dynamics in H_{2}O. The approach presented in this work uniquely disentangles the effects on the vibrational dynamics of four contributions: the delocalization of the O-H stretch mode, structural dynamics of the hydrogen bonded network, intramolecular coupling within water molecules, and intermolecular coupling between water molecules (near-resonant energy transfer between O-H groups. Our results illustrate that intermolecular energy transfer and the delocalization of the O-H stretch mode are particularly important for the spectral diffusion in H_{2}O.

  12. Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma

    Science.gov (United States)

    Litchford, Ron J.; Harada, Nobuhiro

    2011-01-01

    Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test.

  13. The lagRST Model: A Turbulence Model for Non-Equilibrium Flows

    Science.gov (United States)

    Lillard, Randolph P.; Oliver, A. Brandon; Olsen, Michael E.; Blaisdell, Gregory A.; Lyrintzis, Anastasios S.

    2011-01-01

    This study presents a new class of turbulence model designed for wall bounded, high Reynolds number flows with separation. The model addresses deficiencies seen in the modeling of nonequilibrium turbulent flows. These flows generally have variable adverse pressure gradients which cause the turbulent quantities to react at a finite rate to changes in the mean flow quantities. This "lag" in the response of the turbulent quantities can t be modeled by most standard turbulence models, which are designed to model equilibrium turbulent boundary layers. The model presented uses a standard 2-equation model as the baseline for turbulent equilibrium calculations, but adds transport equations to account directly for non-equilibrium effects in the Reynolds Stress Tensor (RST) that are seen in large pressure gradients involving shock waves and separation. Comparisons are made to several standard turbulence modeling validation cases, including an incompressible boundary layer (both neutral and adverse pressure gradients), an incompressible mixing layer and a transonic bump flow. In addition, a hypersonic Shock Wave Turbulent Boundary Layer Interaction with separation is assessed along with a transonic capsule flow. Results show a substantial improvement over the baseline models for transonic separated flows. The results are mixed for the SWTBLI flows assessed. Separation predictions are not as good as the baseline models, but the over prediction of the peak heat flux downstream of the reattachment shock that plagues many models is reduced.

  14. Spectral analysis of nonequilibrium molecular dynamics: Spectral phonon temperature and local nonequilibrium in thin films and across interfaces

    Science.gov (United States)

    Feng, Tianli; Yao, Wenjun; Wang, Zuyuan; Shi, Jingjing; Li, Chuang; Cao, Bingyang; Ruan, Xiulin

    2017-05-01

    Although extensive experimental and theoretical works have been conducted to understand the ballistic and diffusive phonon transport in nanomaterials recently, direct observation of temperature and thermal nonequilibrium of different phonon modes has not been realized. Herein, we have developed a method within the framework of molecular dynamics to calculate the temperatures of phonons in both real and phase spaces. Taking silicon thin film and graphene as examples, we directly obtained the spectral phonon temperature (SPT) and observed the local thermal nonequilibrium between the ballistic and diffusive phonons. Such nonequilibrium also generally exists across interfaces and is surprisingly large, and it provides a significant additional thermal interfacial resistance mechanism besides phonon reflection. Our SPT results directly show that the vertical thermal transport across the dimensionally mismatched graphene-substrate interface is through the coupling between flexural acoustic phonons of graphene and the longitudinal phonons in the substrate with mode conversion. In the dimensionally matched interfaces, e.g., graphene-graphene junction and graphene-boron nitride planar interfaces, strong coupling occurs between the acoustic phonon modes on both sides, and the coupling decreases with interfacial mixing. The SPT method together with the spectral heat flux can eliminate the size effect of the thermal conductivity prediction induced from ballistic transport.

  15. Analysis of Fourier ptychographic microscopy with half reduced images

    Science.gov (United States)

    Zhou, Ao; Chen, Ni; Situ, Guohai

    2018-01-01

    Fourier ptychography microscopy (FPM) provides gigapixel imaging with both a high image resolution and a wide field-of-view (FOV). However, it is time consuming during the image capture process. In this paper, we perform an analysis on the FPM imaging process. With numerical and experimental comparison, we find that the reconstructed high resolution images with half number of the total captured images is less degenerated compare to that using all the captured images, especially in the case that the object is amplitude or phase-only.

  16. Grating-assisted superresolution of slow waves in Fourier space

    DEFF Research Database (Denmark)

    Thomas, N. Le; Houdré, R.; Frandsen, Lars Hagedorn

    2007-01-01

    We present a far-field optical technique allowing the measurement of the dispersion relation of electromagnetic fields propagating under the light cone in photonic nanostuctures. It relies on the use of a one-dimensional grating to probe the evanescent tail of the guided field in combination...... with a high numerical aperture Fourier space imaging set-up. A high-resolution spectroscopy of the far-field emission diagram allows us to accurately and efficiently determine the dispersion curve and the group-index dispersion of planar photonic waveguides operating in the slow light regime....

  17. Calculating thermal radiation of a vibrational nonequilibrium gas flow using the method of k-distribution

    Science.gov (United States)

    Molchanov, A. M.; Bykov, L. V.; Yanyshev, D. S.

    2017-05-01

    The method has been developed to calculate infrared radiation of vibrational nonequilibrium gas based on k-distribution. A comparison of the data on the calculated nonequilibrium radiation with results of other authors and with experimental data has shown satisfactory agreement. It is shown that the results of calculation of radiation intensity using nonequilibrium and equilibrium methods significantly differ from each other. The discrepancy increases with increasing height (decreasing pressure) and can exceed an order of magnitude.

  18. Sensitivity of the fractional Fourier transform to parameters and its application in optical measurement.

    Science.gov (United States)

    Jiang, Z; Lu, Q; Zhao, Y

    1997-11-10

    The fractional Fourier transform (FRT) is becoming important in optics and can be used as a new tool to analyze many optical problems. However, we point out that the FRT might be much more sensitive to parameters than the conventional Fourier transform. This sensitivity leads to higher requirements on the optical implementation. On the other hand, high parametric sensitivity can be used in optical diffraction measurements. We give the first proposal, to our knowledge, of the FRT's applications in optical measurement.

  19. Salmon Muscle Adherence to Polymer Coatings and Determination of Antibiotic Residues by Reversed-Phase High-Performance Liquid Chromatography Coupled to Selected Reaction Monitoring Mass Spectrometry, Atomic Force Microscopy, and Fourier Transform Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    E. Zumelzu

    2015-01-01

    Full Text Available The persistent adhesion of salmon muscle to food container walls after treatment with urea solution was observed. This work evaluated the diffusion of antibiotics from the salmon muscle to the polyethylene terephthalate (PET coating protecting the electrolytic chromium coated steel (ECCS plates. New aquaculture production systems employ antibiotics such as florfenicol, florfenicol amine, oxytetracycline, and erythromycin to control diseases. The introduction of antibiotics is a matter of concern regarding the effects on human health and biodiversity. It is important to determine their impact on the adhesion of postmortem salmon muscle to can walls and the surface and structural changes affecting the functionality of multilayers. This work characterized the changes occurring in the multilayer PET polymer and steel of containers by electron microscopy, 3D atomic force microscopy (3D-AFM, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectroscopy (FT-IR analyses. A robust mass spectrometry methodology was employed to determine the presence of antibiotic residues. No evidence of antibiotics was observed on the protective coating in the range between 0.001 and 2.0 ng/mL; however, the presence of proteins, cholesterol, and alpha-carotene was detected. This in-depth profiling of the matrix-level elements is relevant for the use of adequate materials in the canning export industry.

  20. Self-Fourier transform and self-Fourier beams due to parabolic potential

    CERN Document Server

    Zhang, Yiqi; Zhong, Weiping; Zhang, Yanpeng

    2014-01-01

    We theoretically and numerically investigate the propagation of light beams including Hermite-Gaussian, Bessel-Gaussian and finite energy Airy beams in free space with parabolic potential. Expectedly, the beams undergo harmonic oscillation during propagation, but quite unexpectedly they also perform self-Fourier transform, that is, periodic change from the beam to its Fourier transform and back. The oscillating period of parity-asymmetric beams is twice that of the parity-symmetric beams. In addition to oscillation, we find that finite-energy Airy beams exhibit periodic inversion during propagation. Based on the parabolic potential, we introduce a class of optically-interesting beams that are self-Fourier beams, i.e., the corresponding Fourier transforms are themselves. We outline interesting venues for future research.

  1. Generalization of the second law for a transition between nonequilibrium states

    Energy Technology Data Exchange (ETDEWEB)

    Takara, K. [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Hasegawa, H.-H., E-mail: hhh@mx.ibaraki.ac.j [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Center for Complex Quantum Systems, Univ. of Texas, Austin, TX 78712 (United States); Driebe, D.J. [Embry-Riddle Aeronautical University Worldwide, Fort Lauderdale, FL 33309 (United States)

    2010-12-01

    The maximum work formulation of the second law of thermodynamics is generalized for a transition between nonequilibrium states. The relative entropy, the Kullback-Leibler divergence between the nonequilibrium states and the canonical distribution, determines the maximum ability to work. The difference between the final and the initial relative entropies with an effective temperature gives the maximum dissipative work for both adiabatic and isothermal processes. Our formulation reduces to both the Vaikuntanathan-Jarzynski relation and the nonequilibrium Clausius relation in certain situations. By applying our formulation to a heat engine the Carnot cycle is generalized to a circulation among nonequilibrium states.

  2. Nonequilibrium statistical Zubarev's operator and Green's functions for an inhomogeneous electron gas

    Directory of Open Access Journals (Sweden)

    P.Kostrobii

    2006-01-01

    Full Text Available Nonequilibrium properties of an inhomogeneous electron gas are studied using the method of the nonequilibrium statistical operator by D.N. Zubarev. Generalized transport equations for the mean values of inhomogeneous operators of the electron number density, momentum density, and total energy density for weakly and strongly nonequilibrium states are obtained. We derive a chain of equations for the Green's functions, which connects commutative time-dependent Green's functions "density-density", "momentum-momentum", "enthalpy-enthalpy" with reduced Green's functions of the generalized transport coefficients and with Green's functions for higher order memory kernels in the case of a weakly nonequilibrium spatially inhomogeneous electron gas.

  3. Self-Fourier transform and self-Fourier beams due to parabolic potential

    OpenAIRE

    Zhang, Yiqi; Liu, Xing; Belić, Milivoj R.; Zhong, Weiping; Petrović, Milan S.; Zhang, Yanpeng

    2014-01-01

    We investigate the propagation of light beams including Hermite-Gauss, Bessel-Gauss and finite energy Airy beams in a linear medium with parabolic potential. Expectedly, the beams undergo oscillation during propagation, but quite unexpectedly they also perform automatic Fourier transform, that is, periodic change from the beam to its Fourier transform and back. The oscillating period of parity-asymmetric beams is twice that of the parity-symmetric beams. In addition to oscillation, the finite...

  4. Phase-field investigation on the non-equilibrium interface dynamics of rapid alloy solidification

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    The research program reported here is focused on critical issues that represent conspicuous gaps in current understanding of rapid solidification, limiting our ability to predict and control microstructural evolution (i.e. morphological dynamics and microsegregation) at high undercooling, where conditions depart significantly from local equilibrium. More specifically, through careful application of phase-field modeling, using appropriate thin-interface and anti-trapping corrections and addressing important details such as transient effects and a velocity-dependent (i.e. adaptive) numerics, the current analysis provides a reasonable simulation-based picture of non-equilibrium solute partitioning and the corresponding oscillatory dynamics associated with single-phase rapid solidification and show that this method is a suitable means for a self-consistent simulation of transient behavior and operating point selection under rapid growth conditions. Moving beyond the limitations of conventional theoretical/analytical treatments of non-equilibrium solute partitioning, these results serve to substantiate recent experimental findings and analytical treatments for single-phase rapid solidification. The departure from the equilibrium solid concentration at the solid-liquid interface was often observed during rapid solidification, and the energetic associated non-equilibrium solute partitioning has been treated in detail, providing possible ranges of interface concentrations for a given growth condition. Use of these treatments for analytical description of specific single-phase dendritic and cellular operating point selection, however, requires a model for solute partitioning under a given set of growth conditions. Therefore, analytical solute trapping models which describe the chemical partitioning as a function of steady state interface velocities have been developed and widely utilized in most of the theoretical investigations of rapid solidification. However, these

  5. Nonequilibrium Molecular Energy Coupling and Conversion Mechanisms

    Science.gov (United States)

    2016-08-28

    N2(v=1) + N2(w-1), due to overpopulation of high vibrational levels, N2(w>2), during the discharge pulse. This results in net vibrational energy...transfer to the low levels in the afterglow, transient overpopulation of N2(v=1), and increase of the “first level” N2 vibrational temperature...it can be seen that the overall trend of transient overpopulation of v=1 and gradual decay of higher level DISTRIBUTION A: Distribution approved for

  6. Transmitter-receiver system for time average fourier telescopy

    Science.gov (United States)

    Pava, Diego Fernando

    Time Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse twodimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the object is collected by a "light-buckt" detector, and the resulting electrical signal is digitized and subjected to a series of signal processing operations, including an all-critical averaging of the amplitude and phase of a number of narrow-band signals. This dissertation reports on the formulation and analysis of a transmitter-receiver system appropriate for the illumination, signal detection, and signal processing required for successful application of the TAFT concept. The analysis assumes a Kolmogorov model for the atmospheric turbulence, that the object is rough on the scale of the optical wavelength of the illumination pattern, and that the object is not changing with time during the image-formation interval. An important original contribution of this work is the development of design principles for spatio-temporal non-redundant arrays of active sources for object illumination. Spatial non-redundancy has received considerable attention in connection with the arrays of antennas used in radio astronomy. The work reported here explores different alternatives and suggests the use of two-dimensional cyclic difference sets, which favor low frequencies in the spatial frequency domain. The temporal nonredundancy condition requires that all active sources oscillate at a different optical frequency and that the frequency difference between any two sources be unique. A novel algorithm for generating the array, based on optimized perfect cyclic difference sets, is described

  7. Fourier analysis: from cloaking to imaging

    Science.gov (United States)

    Wu, Kedi; Cheng, Qiluan; Wang, Guo Ping

    2016-04-01

    Regarding invisibility cloaks as an optical imaging system, we present a Fourier approach to analytically unify both Pendry cloaks and complementary media-based invisibility cloaks into one kind of cloak. By synthesizing different transfer functions, we can construct different devices to realize a series of interesting functions such as hiding objects (events), creating illusions, and performing perfect imaging. In this article, we give a brief review on recent works of applying Fourier approach to analysis invisibility cloaks and optical imaging through scattering layers. We show that, to construct devices to conceal an object, no constructive materials with extreme properties are required, making most, if not all, of the above functions realizable by using naturally occurring materials. As instances, we experimentally verify a method of directionally hiding distant objects and create illusions by using all-dielectric materials, and further demonstrate a non-invasive method of imaging objects completely hidden by scattering layers.

  8. Fourier transform (FT)-artifacts and power-function resolution filter in Fourier transform mass spectrometry.

    Science.gov (United States)

    Kanawati, Basem; Bader, Theresa M; Wanczek, Karl-Peter; Li, Yan; Schmitt-Kopplin, Philippe

    2017-10-15

    Peak picking algorithms in mass spectrometry face the challenge of picking the correct signals from a mass spectrum. In some cases signal wiggles (side lobes) are also chosen in the produced mass list as if they were real signals. Constraints which are defined in such algorithms do not always guarantee wiggle-free accurate mass list generation out of raw mass spectra. This problem intensifies with acquisitions, which are accompanied by longer transients. Thus, the problem represents a contemporary issue, which propagates with modern high-memory digitizers and exists in both MS and MS/MS spectra. A solariX FTMS mass spectrometer with an Infinity ICR cell (Bruker Daltonics, Bremen, Germany) coupled to a 12 Tesla magnet (Magnex, UK) was used for the experimental study. Time-domain transients of several different data point lengths 512k, 1M, 2M, 4M, 8M were obtained and were Fourier-transformed to obtain frequency spectra which show the effect of the transient truncation on sinc wiggle developments in FT-ICR-MS. MATLAB simulations were also performed to investigate the origin of the Fourier transform (FT)-artifacts. A new filter has been developed to identify and remove FT-artifacts (sinc side lobes) from both frequency and mass spectra. The newly developed filter is based on distinguishing between the FWHM of the correct frequency/mass signals and the FWHM of their corresponding wiggles. The filter draws a reliable confidence limit of resolution range, within which a correct frequency/mass signal is identified. The filter is applicable over a wide mass range of metabolic interest (100-1200 amu). The origin of FT-artifacts due to time-domain transient truncations was thoroughly investigated both experimentally and by simulations in this study. A new solution for this problem with automatic recognition and elimination of these FT-artifacts (side lobes/wiggles) is provided, which is independent of any intensity thresholds, magnetic field strengths and time

  9. A Fourier analysis of extreme events

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; Zhao, Yuwei

    2014-01-01

    The extremogram is an asymptotic correlogram for extreme events constructed from a regularly varying stationary sequence. In this paper, we define a frequency domain analog of the correlogram: a periodogram generated from a suitable sequence of indicator functions of rare events. We derive basic ...... properties of the periodogram such as the asymptotic independence at the Fourier frequencies and use this property to show that weighted versions of the periodogram are consistent estimators of a spectral density derived from the extremogram....

  10. An Imaging Fourier Transform Spectrometer for NGST

    OpenAIRE

    Graham, James R.

    1999-01-01

    Due to its simultaneous deep imaging and integral field spectroscopic capability, an Imaging Fourier Transform Spectrograph (IFTS) is ideally suited to the Next Generation Space Telescope (NGST) mission, and offers opportunities for tremendous scientific return in many fields of astrophysical inquiry. We describe the operation and quantify the advantages of an IFTS for space applications. The conceptual design of the Integral Field Infrared Spectrograph (IFIRS) is a wide field (5'.3 x 5'.3) f...

  11. Nonequilibrium clumped isotope signals in microbial methane

    Science.gov (United States)

    Wang, David T.; Gruen, Danielle S.; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C.; Holden, James F.; Hristov, Alexander N.; Pohlman, John W.; Morrill, Penny L.; Könneke, Martin; Delwiche, Kyle B.; Reeves, Eoghan P.; Sutcliffe, Chelsea N.; Ritter, Daniel J.; Seewald, Jeffrey S.; McIntosh, Jennifer C.; Hemond, Harold F.; Kubo, Michael D.; Cardace, Dawn; Hoehler, Tori M.; Ono, Shuhei

    2015-01-01

    Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

  12. Qualitative Aspects Of Non-Equilibrium Statistical Distributions For Turbulent Flows

    Directory of Open Access Journals (Sweden)

    Devashish Vikas Gupta

    2015-08-01

    Full Text Available This paper puts forward the key features of plausible time-evolving statistical distributions of the Scale and Spin of eddies describing the phenomenon of turbulence. Statistical distributions generally describe the state of the system in equilibrium states but describing turbulent flows demands non-equilibrium statistics as there is energy dissipation due to viscosity of the fluid and variations in macroscopic properties of the system with time. The approach put forward proves to be highly advantageous to explain the variation of eddy scale using the Scale Displacement Equation. It ascertains a huge gain in understanding characteristics of the fluids subject to high Reynolds numbers. The phenomenon of Spin Interference which is responsible for the variation of eddy spin in the system is also described intensively. The put forth Scale and Spin statistics parametrized by time demonstrate some interesting features that are fundamentally linked to the behaviour of fluids.

  13. Effects of non-equilibrium particle distributions in deuterium-tritium burning

    Energy Technology Data Exchange (ETDEWEB)

    Michta, D; Graziani, F; Pruet, J; Luu, T

    2009-08-18

    We investigate the effects of non-equilibrium particle distributions resulting from rapid deuterium-tritium burning in plasmas using a Fokker-Planck code that incorporates small-angle Coulomb scattering, Brehmsstrahlung, Compton scattering, and thermal-nuclear burning. We find that in inertial confinement fusion environments, deviations away from Maxwellian distributions for either deuterium or tritium ions are small and result in 1% changes in the energy production rates. The deuterium and tritium effective temperatures are not equal, but differ by only about 2.5% near the time of peak burn rate. Simulations with high Z (Xe) dopants show that the dopant temperature closely tracks that of the fuel. On the other hand, fusion product ion distributions are highly non-Maxwellian, and careful treatments of energy-exchange between these ions and other particles is important for determining burn rates.

  14. Entropic screening preserves non-equilibrium nature of nematic phase while enthalpic screening destroys it.

    Science.gov (United States)

    Dan, K; Roy, M; Datta, A

    2016-02-14

    The present manuscript describes the role of entropic and enthalpic forces mediated by organic non-polar (hexane) and polar (methanol) solvents on the bulk and microscopic phase transition of a well known nematic liquid crystalline material MBBA (N-(4-methoxybenzylidene)-4-butylaniline) through Differential Scanning calorimetry (DSC), UV-Visible (UV-Vis), and Fourier Transform Infrared (FTIR) spectroscopy. DSC study indicates continuous linear decreases in both nematic-isotropic (N-I) phase transition temperature and enthalpy of MBBA in presence of hexane while both these parameters show a saturation after an initial decay in methanol. These distinct transitional behaviours were explained in terms of the "depletion force" model for entropic screening in hexane and "screening-self-screening" model for methanol. Heating rate dependent DSC studies find that non-Arrhenius behaviour, characteristic of pristine MBBA and a manifestation of non-equilibrium nature [Dan et al., J. Chem. Phys. 143, 094501 (2015)], is preserved in presence of entropic screening in the hexane solution, while it changes to Arrhenius behaviour (signifying equilibrium behaviour) in presence of enthalpic screening in methanol solution. FTIR spectra show similar dependence on the solvent induced screening in the intensities of the imine (-C = N) stretch and the out-of-plane distortion vibrations of the benzene rings of MBBA with hexane and methanol as in DSC, further establishing our entropic and enthalpic screening models. UV-Vis spectra of the electronic transitions in MBBA as a function of temperature also exhibit different dependences of intensities on the solvent induced screening, and an exponential decrease is observed in presence of hexane while methanol completely changes the nature of interaction to follow a linear dependence.

  15. The derivative-free Fourier shell identity for photoacoustics.

    Science.gov (United States)

    Baddour, Natalie

    2016-01-01

    In X-ray tomography, the Fourier slice theorem provides a relationship between the Fourier components of the object being imaged and the measured projection data. The Fourier slice theorem is the basis for X-ray Fourier-based tomographic inversion techniques. A similar relationship, referred to as the 'Fourier shell identity' has been previously derived for photoacoustic applications. However, this identity relates the pressure wavefield data function and its normal derivative measured on an arbitrary enclosing aperture to the three-dimensional Fourier transform of the enclosed object evaluated on a sphere. Since the normal derivative of pressure is not normally measured, the applicability of the formulation is limited in this form. In this paper, alternative derivations of the Fourier shell identity in 1D, 2D polar and 3D spherical polar coordinates are presented. The presented formulations do not require the normal derivative of pressure, thereby lending the formulas directly adaptable for Fourier based absorber reconstructions.

  16. Atomic transition probabilities of Ce I from Fourier transform spectra

    Science.gov (United States)

    Lawler, J. E.; Chisholm, J.; Nitz, D. E.; Wood, M. P.; Sobeck, J.; Den Hartog, E. A.

    2010-04-01

    Atomic transition probabilities for 2874 lines of the first spectrum of cerium (Ce I) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 085006). The wavelength range of the data set is from 360 to 1500 nm. Comparisons are made to previous investigations which are less extensive. Accurate Ce i transition probabilities are needed for lighting research and development on metal halide high-intensity discharge lamps.

  17. Atomic transition probabilities of Ce I from Fourier transform spectra

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J E; Wood, M P; Den Hartog, E A [Department of Physics, University of Wisconsin, 1150 University Ave., Madison, WI 53706 (United States); Chisholm, J [Department of Physics, Boston College, 140 Commonwealth Ave., Chestnut Hill, MA 02467 (United States); Nitz, D E [Department of Physics, St. Olaf College, 1520 St. Olaf Ave., Northfield, MN 55057 (United States); Sobeck, J, E-mail: jelawler@wisc.ed, E-mail: chishojd@bc.ed, E-mail: nitz@stolaf.ed, E-mail: mpwood@wisc.ed, E-mail: jsobeck@uchicago.ed, E-mail: eadenhar@wisc.ed [Department of Astronomy and Astrophysics, University of Chicago, 5640 Ellis Ave., Chicago, IL 60637 (United States)

    2010-04-28

    Atomic transition probabilities for 2874 lines of the first spectrum of cerium (Ce I) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 085006). The wavelength range of the data set is from 360 to 1500 nm. Comparisons are made to previous investigations which are less extensive. Accurate Ce i transition probabilities are needed for lighting research and development on metal halide high-intensity discharge lamps.

  18. Magneto-sensor circuit efficiency incremented by Fourier-transformation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2011-10-01

    In this paper detection by recognized intelligent algorithm for different magnetic films with the aid of a cost-effective and simple high efficient circuit are realized. Well-known, magnetic films generate oscillating frequencies when they stay a part of an LC- oscillatory circuit. These frequencies can be further analyzed to gather information about their magnetic properties. For the first time in this work we apply the signal analysis in frequency domain to create the Fourier frequency spectra which was used to detect the sample properties and their recognition. In this paper we have summarized both the simulation and experimental results. © 2011 Elsevier Ltd. All rights reserved.

  19. PREFACE: First International Workshop on Nonequilibrium Processes in Plasma Physics and Studies of Environment

    Science.gov (United States)

    Petrović, Z. Lj; Malović, G.; Tasić, M.; Nikitović, Ž.

    2007-06-01

    from many different standpoints. A special case of non-equilibrium is that of non-neutral plasmas, i.e. plasmas devoid of ions, as described in the lecture and paper by J Marler (Appleton, USA). Physics of swarms (the low space charge limit of ionized gases) is similar to the previous study in the fact that we may have only one group of charged particles electrons (or ions). But the difference is that the latter has a much higher pressure and therefore number of collisions. In the lecture on one aspect of the application of swarm data (transport coefficients) to determine the electron scattering cross sections R White (Townsville, Australia) addresses a long standing controversy in the vibrational excitation of H2 of an unacceptable discrepancy between swarm results and binary collision experiments and theories, (a problem that has been of particular importance to the host Laboratory). The lecture of N Dyatko (Troitsk, Russian Federation) tackles one of the most interesting recent problems in the transport theory of ionized gases, that of the negative absolute conductivity and attempts to translate it to solid state physics where the stakes are much higher. The swarm studies were always based on excellent experimental data and the leading experimental group today is that of J de Urquijo (Cuernavaca, Mexico) who presents a review of a wide range of transport data that his group obtained in fluorinated gases. The gas breakdown in dc and high frequency fields was addressed by M Radmilović-Rađenović (Belgrade, Serbia) by applying a detailed secondary electron production model in Particle in Cell (PIC) code and comparing the results to a broad range of experimental data. The hybrid (fluid-Monte Carlo) model has been applied in the study by Z Donko and K Kutasi (Budapest, Hungary) of low pressure obstructed glow discharges to decribe the effect of fast neutrals on gas discharges. A study of kinetics of negative ions of hydrogen in glow discharges with positive column and

  20. Non-equilibrium steady state in the hydro regime

    Energy Technology Data Exchange (ETDEWEB)

    Pourhasan, Razieh [Science Institute, University of Iceland,Dunhaga 5, 107 Reykjavik (Iceland)

    2016-02-01

    We study the existence and properties of the non-equilibrium steady state which arises by putting two copies of systems at different temperatures into a thermal contact. We solve the problem for the relativistic systems that are described by the energy-momentum of a perfect hydro with general equation of state (EOS). In particular, we examine several simple examples: a hydro with a linear EOS, a holographic CFT perturbed by a relevant operator and a barotropic fluid, i.e., P=P(E). Our studies suggest that the formation of steady state is a universal result of the hydro regime regardless of the kind of fluid.

  1. Dynamics of nonequilibrium thermal entanglement for simple spin chains

    Science.gov (United States)

    Sinayskiy, I.; Pumulo, N.; Petruccione, F.

    2011-10-01

    The dynamics of simple spin chains of two and three spins coupled at both ends to separate bosonic baths at different temperatures is studied. An exact analytical solution of the master equation in the Born-Markov approximation for the reduced density matrix of the chain is constructed. It is shown that for long times the reduced density matrix converges to the non-equilibrium steady-state. Dynamical and steady state properties of the concurrence between the first and the last spin are studied.

  2. Exploiting non-equilibrium phase separation for self-assembly.

    Science.gov (United States)

    Grünwald, Michael; Tricard, Simon; Whitesides, George M; Geissler, Phillip L

    2016-02-07

    Demixing can occur in systems of two or more particle species that experience different driving forces, e.g., mixtures of self-propelled active particles or of oppositely charged colloids subject to an electric field. Here we show with macroscopic experiments and computer simulations that the forces underlying such non-equilibrium segregation can be used to control the self-assembly of particles that lack attractive interactions. We demonstrate that, depending on the direction, amplitude and frequency of a periodic external force acting on one particle species, the structures formed by a second, undriven species can range from compact clusters to elongated, string-like patterns.

  3. Nonequilibrium optical conductivity: General theory and application to transient phases

    Science.gov (United States)

    Kennes, D. M.; Wilner, E. Y.; Reichman, D. R.; Millis, A. J.

    2017-08-01

    A nonequilibrium theory of optical conductivity of dirty-limit superconductors and commensurate charge density wave is presented. We discuss the current response to different experimentally relevant light-field probe pulses and show that a single frequency definition of the optical conductivity σ (ω )≡j (ω )/E (ω ) is difficult to interpret out of the adiabatic limit. We identify characteristic time-domain signatures distinguishing between superconducting, normal-metal, and charge density wave states. We also suggest a route to directly address the instantaneous superfluid stiffness of a superconductor by shaping the probe light field.

  4. Non-equilibrium Kondo effect in double quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Kiselev, M.N. E-mail: kiselev@physik.uni-wuerzburg.de; Kikoin, K.A.; Molenkamp, L.W

    2004-05-01

    We investigate theoretically a non-equilibrium transport through a double quantum dot (DQD) in a parallel geometry. It is shown that the resonance Kondo tunneling through a parallel DQD with even occupation and singlet ground state may arise at a strong bias, which compensates the energy of singlet/triplet excitation. Using the renormalization group technique we derive scaling equations and calculate the differential conductance as a function of an auxiliary DC-bias for parallel DQD being in a regime described by SO(4) symmetry.

  5. Non-equilibrium temperature of well-developed quantum turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Jou, D. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Mongiovi, M.S., E-mail: mongiovi@unipa.i [Dipartimento di Metodi e Modelli Matematici, Universita di Palermo, Facolta di Ingegneria, Viale delle Scienze, 90128 Palermo (Italy)

    2009-06-22

    A non-equilibrium effective temperature of quantum vortex tangles is defined as the average energy of closed vortex loops. The resulting thermodynamic expressions for the entropy and the energy in terms of the temperature of the tangle are confirmed by a microscopic analysis based on a potential distribution function for the length of vortex loops. Furthermore, these expressions for the entropy and energy in terms of temperature are analogous to those of black holes: this may be of interest for establishing further connections between topological defects in superfluids and cosmology.

  6. Quantum reciprocity conjecture for the non-equilibrium steady state

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, P; Mao, W [Center for Materials Theory, Rutgers University, Piscataway, NJ 08854 (United States)

    2004-05-26

    A consideration of the lack of history dependence in the non-equilibrium steady state of a quantum system leads us to conjecture that in such a system there is a set of quantum mechanical observables whose retarded response functions are insensitive to the arrow of time, and which consequently satisfy a quantum analogue of the Onsager reciprocity relations. Systems which satisfy this conjecture can be described by an effective free energy functional. We demonstrate that the conjecture holds in a resonant level model of a multi-lead quantum dot. (letter to the editor)

  7. Effects of vacancies on overshooting in nonequilibrium ordering processes

    DEFF Research Database (Denmark)

    Gilhøj, Henriette; Jeppesen, Claus; Mouritsen, Ole G.

    1996-01-01

    The effects of annealed site dilution on the nonequilibrium ordering process in the two-dimensional Ising model with a nonconserved order parameter have been studied using Monte Carlo simulation. It is found that the transient development of a local order that is larger than the equilibrium order...... (overshooting), as recently reported in the pure Ising model [H. Gilhoj, C. Jeppesen, and O. G; Mouritsen, Phys. Rev. Lett. 75, 3305 (1995)], persists in the dilute model and is accompanied by a depletion of the vacancies within the ordered domains....

  8. Ethanol reforming in non-equilibrium plasma of glow discharge

    CERN Document Server

    Levko, D

    2012-01-01

    The results of a detailed kinetic study of the main plasma chemical processes in non-equilibrium ethanol/argon plasma are presented. It is shown that at the beginning of the discharge the molecular hydrogen is mainly generated in the reaction of ethanol H-abstraction. Later hydrogen is formed from active H, CH2OH and CH3CHOH and formaldehyde. Comparison with experimental data has shown that the used kinetic mechanism predicts well the concentrations of main species at the reactor outlet.

  9. Nonequilibrium Microscopic Distribution of Thermal Current in Particle Systems

    KAUST Repository

    Yukawa, Satoshi

    2009-02-15

    A nonequilibrium distribution function of microscopic thermal current is studied by a direct numerical simulation in a thermal conducting steady state of particle systems. Two characteristic temperatures of the thermal current are investigated on the basis of the distribution. It is confirmed that the temperature depends on the current direction; Parallel temperature to the heat-flux is higher than antiparallel one. The difference between the parallel temperature and the antiparallel one is proportional to a macroscopic temperature gradient. ©2009 The Physical Society of Japan.

  10. Non-equilibrium dynamics of isolated quantum systems

    Directory of Open Access Journals (Sweden)

    Calabrese Pasquale

    2015-01-01

    Full Text Available The non-equilibrium dynamics of isolated quantum systems represent a theoretical and experimental challenge raising many fundamental questions with applications to different fields of modern physics. In these proceedings, we briefly review some of the recent findings on the subject, with particular emphasis to the existence of stationary expectation values of local observables and to their statistical mechanics description. It turns out that the appropriate statistical ensemble describing these asymptotic values depends on whether the Hamiltonian governing the time evolution is integrable or not.

  11. Optical spectroscopy of molecular junctions: Nonequilibrium Green's functions perspective.

    Science.gov (United States)

    Gao, Yi; Galperin, Michael

    2016-05-07

    We consider optical spectroscopy of molecular junctions from the quantum transport perspective when radiation field is quantized and optical response of the system is simulated as photon flux. Using exact expressions for photon and electronic fluxes derived within the nonequilibrium Green function (NEGF) methodology and utilizing fourth order diagrammatic perturbation theory (PT) in molecular coupling to radiation field, we perform simulations employing realistic parameters. Results of the simulations are compared to the bare PT which is usually employed in studies on nonlinear optical spectroscopy to classify optical processes. We show that the bare PT violates conservation laws, while flux conserving NEGF formulation mixes optical processes.

  12. The non-equilibrium nature of culinary evolution

    Science.gov (United States)

    Kinouchi, Osame; Diez-Garcia, Rosa W.; Holanda, Adriano J.; Zambianchi, Pedro; Roque, Antonio C.

    2008-07-01

    Food is an essential part of civilization, with a scope that ranges from the biological to the economic and cultural levels. Here, we study the statistics of ingredients and recipes taken from Brazilian, British, French and Medieval cookery books. We find universal distributions with scale invariant behaviour. We propose a copy-mutate process to model culinary evolution that fits our empirical data very well. We find a cultural 'founder effect' produced by the non-equilibrium dynamics of the model. Both the invariant and idiosyncratic aspects of culture are accounted for by our model, which may have applications in other kinds of evolutionary processes.

  13. Universal Scaling Behavior of Non-Equilibrium Phase Transitions

    Science.gov (United States)

    Lübeck, Sven

    Non-equilibrium critical phenomena have attracted a lot of research interest in the recent decades. Similar to equilibrium critical phenomena, the concept of universality remains the major tool to order the great variety of non-equilibrium phase transitions systematically. All systems belonging to a given universality class share the same set of critical exponents, and certain scaling functions become identical near the critical point. It is known that the scaling functions vary more widely between different universality classes than the exponents. Thus, universal scaling functions offer a sensitive and accurate test for a system's universality class. On the other hand, universal scaling functions demonstrate the robustness of a given universality class impressively. Unfortunately, most studies focus on the determination of the critical exponents, neglecting the universal scaling functions. In this work a particular class of non-equilibrium critical phenomena is considered, the so-called absorbing phase transitions. Absorbing phase transitions are expected to occur in physical, chemical as well as biological systems, and a detailed introduction is presented. The universal scaling behavior of two different universality classes is analyzed in detail, namely the directed percolation and the Manna universality class. Especially, directed percolation is the most common universality class of absorbing phase transitions. The presented picture gallery of universal scaling functions includes steady state, dynamical as well as finite size scaling functions. In particular, the effect of an external field conjugated to the order parameter is investigated. Incorporating the conjugated field, it is possible to determine the equation of state, the susceptibility, and to perform a modified finite-size scaling analysis appropriate for absorbing phase transitions. Focusing on these equations, the obtained results can be applied to other non-equilibrium continuous phase transitions

  14. Heat-pulse propagation along nonequilibrium nanowires in thermomass theory

    Directory of Open Access Journals (Sweden)

    Sellitto Antonio

    2016-06-01

    Full Text Available We analyze the consequences of the nonlinear terms in the heat-transport equation of the thermomass theory on heat pulses propagating in a nanowire in nonequilibrium situations. As a consequence of the temperature dependence of the speeds of propagation, in temperature ranges wherein the specific heat shows negligible variations, heat pulses will shrink (or extend spatially, and will increase (or decrease their average temperature when propagating along a temperature gradient. A comparison with the results predicted by a different theoretical proposal on the shape of a propagating heat pulse is made, too.

  15. Collisional-radiative nonequilibrium in partially ionized atomic nitrogen

    Science.gov (United States)

    Kunc, J. A.; Soon, W. H.

    1989-01-01

    A nonlinear collisional-radiative model for determination of nonequilibrium production of electrons, excited atoms, and bound-bound, dielectronic and continuum line intensities in stationary partially ionized atomic nitrogen is presented. Populations of 14 atomic levels and line intensities are calculated in plasma with T(e) = 8000-15,000 K and N(t) = 10 to the 12th - 10 to the 18th/cu cm. Transport of radiation is included by coupling the rate equations of production of the electrons and excited atoms with the radiation escape factors, which are not constant but depend on plasma conditions.

  16. Nonequilibrium thermodynamics and energy efficiency in weight loss diets

    Directory of Open Access Journals (Sweden)

    Fine Eugene J

    2007-07-01

    Full Text Available Abstract Carbohydrate restriction as a strategy for control of obesity is based on two effects: a behavioral effect, spontaneous reduction in caloric intake and a metabolic effect, an apparent reduction in energy efficiency, greater weight loss per calorie consumed. Variable energy efficiency is established in many contexts (hormonal imbalance, weight regain and knock-out experiments in animal models, but in the area of the effect of macronutrient composition on weight loss, controversy remains. Resistance to the idea comes from a perception that variable weight loss on isocaloric diets would somehow violate the laws of thermodynamics, that is, only caloric intake is important ("a calorie is a calorie". Previous explanations of how the phenomenon occurs, based on equilibrium thermodynamics, emphasized the inefficiencies introduced by substrate cycling and requirements for increased gluconeogenesis. Living systems, however, are maintained far from equilibrium, and metabolism is controlled by the regulation of the rates of enzymatic reactions. The principles of nonequilibrium thermodynamics which emphasize kinetic fluxes as well as thermodynamic forces should therefore also be considered. Here we review the principles of nonequilibrium thermodynamics and provide an approach to the problem of maintenance and change in body mass by recasting the problem of TAG accumulation and breakdown in the adipocyte in the language of nonequilibrium thermodynamics. We describe adipocyte physiology in terms of cycling between an efficient storage mode and a dissipative mode. Experimentally, this is measured in the rate of fatty acid flux and fatty acid oxidation. Hormonal levels controlled by changes in dietary carbohydrate regulate the relative contributions of the efficient and dissipative parts of the cycle. While no experiment exists that measures all relevant variables, the model is supported by evidence in the literature that 1 dietary carbohydrate, via its

  17. Shape characteristics of equilibrium and non-equilibrium fractal clusters.

    Science.gov (United States)

    Mansfield, Marc L; Douglas, Jack F

    2013-07-28

    It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other

  18. Nonequilibrium Transport through a Spinful Quantum Dot with Superconducting Leads

    DEFF Research Database (Denmark)

    Andersen, Brian Møller; Flensberg, Karsten; Koerting, Verena

    2011-01-01

    We study the nonlinear cotunneling current through a spinful quantum dot contacted by two superconducting leads. Applying a general nonequilibrium Green function formalism to an effective Kondo model, we study the rich variation in the IV characteristics with varying asymmetry in the tunnel...... coupling to source and drain electrodes. The current is found to be carried, respectively, by multiple Andreev reflections in the symmetric limit, and by spin-induced Yu-Shiba-Rusinov bound states in the strongly asymmetric limit. The interplay between these two mechanisms leads to qualitatively different...

  19. A Note on Fourier and the Greenhouse Effect

    OpenAIRE

    Postma, Joseph E.

    2015-01-01

    Joseph Fourier's discovery of the greenhouse effect is discussed and is compared to the modern conception of the greenhouse effect. It is confirmed that what Fourier discovered is analogous to the modern concept of the greenhouse effect. However, the modern concept of the greenhouse effect is found to be based on a paradoxical analogy to Fourier's greenhouse work and so either Fourier's greenhouse work, the modern conception of the greenhouse effect, or the modern definition of heat is incorr...

  20. Hyperbolic Cross Truncations for Stochastic Fourier Cosine Series

    Science.gov (United States)

    Zhang, Zhihua

    2014-01-01

    Based on our decomposition of stochastic processes and our asymptotic representations of Fourier cosine coefficients, we deduce an asymptotic formula of approximation errors of hyperbolic cross truncations for bivariate stochastic Fourier cosine series. Moreover we propose a kind of Fourier cosine expansions with polynomials factors such that the corresponding Fourier cosine coefficients decay very fast. Although our research is in the setting of stochastic processes, our results are also new for deterministic functions. PMID:25147842

  1. Instrument concept of the imaging Fourier transform spectrometer GLORIA

    Directory of Open Access Journals (Sweden)

    F. Friedl-Vallon

    2014-10-01

    Full Text Available The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA is an imaging limb emission sounder operating in the thermal infrared region. It is designed to provide measurements of the upper troposphere/lower stratosphere with high spatial and high spectral resolution. The instrument consists of an imaging Fourier transform spectrometer integrated into a gimbal. The assembly can be mounted in the belly pod of the German High Altitude and Long Range research aircraft (HALO and in instrument bays of the Russian M55 Geophysica. Measurements are made in two distinct modes: the chemistry mode emphasises chemical analysis with high spectral resolution, and the dynamics mode focuses on dynamical processes of the atmosphere with very high spatial resolution. In addition, the instrument allows tomographic analyses of air volumes. The first measurement campaigns have shown compliance with key performance and operational requirements.

  2. Multidistortion-invariant image recognition with radial harmonic Fourier moments.

    Science.gov (United States)

    Ren, Haiping; Ping, Ziliang; Bo, Wurigen; Wu, Wenkai; Sheng, Yunlong

    2003-04-01

    We propose radial harmonic Fourier moments, which are shifting, scaling, rotation, and intensity invariant. Compared with Chebyshev-Fourier moments, the new moments have superior performance near the origin and better ability to describe small images in terms of image-reconstruction errors and noise sensitivity. A multidistortion-invariant pattern-recognition experiment was performed with radial harmonic Fourier moments.

  3. Image-scaling problem in the optical fractional Fourier transform.

    Science.gov (United States)

    Liu, S; Ren, H; Zhang, J; Zhang, X

    1997-08-10

    The significance of scale factors and cascade of optical fractional Fourier transform is emphasized. Exact and cascadable fractional Fourier transforms in practical applications mandate that the image scale be the reciprocal of the scale of the input plane controlled by the optical setup. The practical setup of the optical fractional Fourier transform must be without any quadratic phase term at the spectrum plane.

  4. Fourier Transforms Simplified: Computing an Infrared Spectrum from an Interferogram

    Science.gov (United States)

    Hanley, Quentin S.

    2012-01-01

    Fourier transforms are used widely in chemistry and allied sciences. Examples include infrared, nuclear magnetic resonance, and mass spectroscopies. A thorough understanding of Fourier methods assists the understanding of microscopy, X-ray diffraction, and diffraction gratings. The theory of Fourier transforms has been presented in this "Journal",…

  5. On-line textile quality control using optical Fourier transforms

    Science.gov (United States)

    Castellini, C.; Francini, F.; Longobardi, G.; Tiribilli, B.; Sansoni, P.

    Fourier transformation and spatial filtering offer the possibility of detecting structural defects in a fabric. In this paper a method based on an optical Fourier transform technique during the weaving process is described. Significant variations in the Fourier pattern occurring in the presence of defective fabric are recognised with a CCD sensor joined to an electronic hardware system performing a simple algorithm.

  6. Some Applications of Fourier's Great Discovery for Beginners

    Science.gov (United States)

    Kraftmakher, Yaakov

    2012-01-01

    Nearly two centuries ago, Fourier discovered that any periodic function of period T can be presented as a sum of sine waveforms of frequencies equal to an integer times the fundamental frequency [omega] = 2[pi]/T (Fourier's series). It is impossible to overestimate the importance of Fourier's discovery, and all physics or engineering students…

  7. Numerical study of nonequilibrium plasma assisted detonation initiation in detonation tube

    Science.gov (United States)

    Zhou, Siyin; Wang, Fang; Che, Xueke; Nie, Wansheng

    2016-12-01

    Nonequilibrium plasma has shown great merits in ignition and combustion nowadays, which should be especially useful for hypersonic propulsion. A coaxial electrodes configuration was established to investigate the effect of alternating current (AC) dielectric barrier discharge nonequilibrium plasma on the detonation initiation process in a hydrogen-oxygen mixture. A discharge simulation-combustion simulation loosely coupled method was used to simulate plasma assisted detonation initiation. First, the dielectric barrier discharge in the hydrogen-oxygen mixture driven by an AC voltage was simulated, which takes 17 kinds of particles (including positively charged particles, negatively charged particles, and neutral particles) and 47 reactions into account. The temporal and spatial characteristics of the discharge products were obtained. Then, the discharge products were incorporated into the combustion model of a detonation combustor as the initial conditions for the later detonation initiation simulation. Results showed that the number density distributions of plasma species are different in space and time, and develop highly nonuniformly from high voltage electrode to grounded electrode at certain times. All the active species reach their highest concentration at approximately 0.6T (T denotes a discharge cycle). Compared with the no plasma case, the differences of flowfield shape mainly appear in the early stage of the deflagration to detonation transition process. None of the sub-processes (including the very slow combustion, deflagration, over-driven detonation, detonation decay, and propagation of a self-sustained stable detonation wave) have been removed by the plasma. After the formation of a C-J detonation wave, the whole flowfield remains unchanged. With the help of plasma, the deflagration to detonation transition (DDT) time and distance are reduced by about 11.6% and 12.9%, respectively, which should be attributed to the active particles effect of

  8. Modeling the Non-Equilibrium Process of the Chemical Adsorption of Ammonia on GaN(0001) Reconstructed Surfaces Based on Steepest-Entropy-Ascent Quantum Thermodynamics.

    Science.gov (United States)

    Kusaba, Akira; Li, Guanchen; von Spakovsky, Michael R; Kangawa, Yoshihiro; Kakimoto, Koichi

    2017-08-15

    Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and Nad-H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on Nad-H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.

  9. Influences of overlap index on Fourier ptychography imaging

    Science.gov (United States)

    Wang, Honghong; Rong, Lu; Wang, Dayong; Zhang, Xu; Zhai, Changchao; Panezai, Spozmai; Wang, Yunxin; Zhao, Jie

    2018-01-01

    Fourier ptychography is a new type of synthetic aperture imaging technique based on phase retrieval method which can improve microscopeic imaging performance beyond the diffraction limit of the employed optical components by illuminating the object with oblique waves of different incident angles where the field of view remains unchanged. illumination angle and the overlap rate of spectrum will have a certain impact on the quality of reconstruction. In this paper, we study the effects of illumination angle and spectral overlap rate on the image quality of Fourier ptychography. The simulation results show that increasing the illumination angle and spectral overlap can improve the resolution, but there is a threshold for the key parameters of spectral overlap rate. The convergence rate decreases when the overlap rate exceeds 70%, and the reconstruction process is more time-consuming due to the high overlap rate. However the results of proposed study shows that an overlap of 60% is the optimal choice to acquire a high-quality recovery with high speed.

  10. Equilibrium & Nonequilibrium Fluctuation Effects in Biopolymer Networks

    Science.gov (United States)

    Kachan, Devin Michael

    -stiffening behavior and compare this behavior to the yield stress flow seen in soft glassy fluids. I extend this theory to account for coordination number inhomogeneities and predict a breakdown of universal scaling near the critical point at sufficiently high disorder, and discuss the utility for this type of model in describing biopolymer networks.

  11. Coherent application of a contact structure to formulate Classical Non-Equilibrium Thermodynamics

    NARCIS (Netherlands)

    Knobbe, E; Roekaerts, D.J.E.M.

    2017-01-01

    This contribution presents an outline of a new mathematical formulation for
    Classical Non-Equilibrium Thermodynamics (CNET) based on a contact
    structure in differential geometry. First a non-equilibrium state space is introduced as the third key element besides the first and second law of

  12. Non-equilibrium Transport and Relaxation in Diffusive Nanowires with Kondo Impurities

    DEFF Research Database (Denmark)

    Kroha, Johann; Rosch, Achim; Paaske, Jens

    2003-01-01

    Combining non-equilibrium transport with spectroscopic measurements provides a unique tool for the investigation of the microscopic processes in mesoscopic conductors. Experiments on resistive quantum wires show that the non-equilibrium quasiparticle distribution function f(E,V) as a function of ...

  13. Combined physical and chemical nonequilibrium transport model: Analytical solution, moments, and application to colloids

    Science.gov (United States)

    The transport of solutes and colloids in porous media is influenced by a variety of physical and chemical nonequilibrium processes. A combined physical–chemical nonequilibrium (PCNE) model was therefore used to describe general mass transport. The model partitions the pore space into “mobile” and “i...

  14. On the definition of equilibrium and non-equilibrium states in dynamical systems

    OpenAIRE

    Akimoto, Takuma

    2008-01-01

    We propose a definition of equilibrium and non-equilibrium states in dynamical systems on the basis of the time average. We show numerically that there exists a non-equilibrium non-stationary state in the coupled modified Bernoulli map lattice.

  15. 360-degrees profilometry using strip-light projection coupled to Fourier phase-demodulation.

    Science.gov (United States)

    Servin, Manuel; Padilla, Moises; Garnica, Guillermo

    2016-01-11

    360 degrees (360°) digitalization of three dimensional (3D) solids using a projected light-strip is a well-established technique in academic and commercial profilometers. These profilometers project a light-strip over the digitizing solid while the solid is rotated a full revolution or 360-degrees. Then, a computer program typically extracts the centroid of this light-strip, and by triangulation one obtains the shape of the solid. Here instead of using intensity-based light-strip centroid estimation, we propose to use Fourier phase-demodulation for 360° solid digitalization. The advantage of Fourier demodulation over strip-centroid estimation is that the accuracy of phase-demodulation linearly-increases with the fringe density, while in strip-light the centroid-estimation errors are independent. Here we proposed first to construct a carrier-frequency fringe-pattern by closely adding the individual light-strip images recorded while the solid is being rotated. Next, this high-density fringe-pattern is phase-demodulated using the standard Fourier technique. To test the feasibility of this Fourier demodulation approach, we have digitized two solids with increasing topographic complexity: a Rubik's cube and a plastic model of a human-skull. According to our results, phase demodulation based on the Fourier technique is less noisy than triangulation based on centroid light-strip estimation. Moreover, Fourier demodulation also provides the amplitude of the analytic signal which is a valuable information for the visualization of surface details.

  16. Application of non-equilibrium plasmas in medicine

    Directory of Open Access Journals (Sweden)

    Mojsilović S.

    2012-01-01

    Full Text Available We review the potential of plasma medical applications, the connections to nanotechnologies and the results obtained by our group. A special issue in plasma medicine is the development of the plasma sources that would achieve non-equilibrium at atmospheric pressure in atmospheric gas mixture with no or only marginal heating of the gas, and with desired properties and mechanisms that may be controlled. Our studies have shown that control of radicals or chemically active products of the discharge such as ROS (reactive oxygen species and/or NO may be used to control the growth of the seeds. At the same time specially designed plasma needle and other sources were shown to be efficient to sterilize not only colonies of bacteria but also planctonic samples (microorganisms protected by water or bio films. Finally we have shown that plasma may induce differentiation of stem cells. Non-equilibrium plasmas may be used in detection of different specific markers in medicine. For example proton transfer mass spectroscopy may be employed in detection of volatile organic compounds without their dissociation and thus as a technique for instantaneous measurement of the presence of markers for numerous diseases. [Projekat Ministarstva nauke Republike Srbije, br. ON171037 i br. III41011

  17. Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

    Science.gov (United States)

    Landry, John Gary

    1995-01-01

    Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The equations are solved numerically using the Steger-Warming flux vector splitting method and the Implicit MacCormack method. The results show that uniform flow is produced outside of the boundary layer. Nonequilibrium exists in both the converging and diverging nozzle sections. The boundary layer region is characterized by a marked increase in translational-rotational temperature. The vibrational temperature remains frozen downstream of the nozzle, except in the boundary layer.

  18. Understanding Non-equilibrium Thermodynamics Foundations, Applications, Frontiers

    CERN Document Server

    Jou, David; Lebon, Georgy

    2007-01-01

    This book offers a homogeneous presentation of the many faces of non-equilibrium thermodynamics. The first part is devoted to a description of the nowadays thermodynamic formalism recognized as the classical theory of non-equilibrium processes. This part of the book may serve as a basis to an introductory course dedicated to first-year graduate students in sciences and engineering. The classical description can however not be complete, as it rests on the hypothesis of local equilibrium. This has fostered the development of many theories going beyond local equilibrium and which cannot be put aside. The second part of the book is concerned with these different approaches, and will be of special interest for PhD students and researchers. For the sake of homogeneity, the authors have used the general structure and methods presented in the first part. Indeed, besides their differences, all these formalisms are not closed boxes but present some overlappings and parallelisms which are emphasized in this book. For pe...

  19. Modeling Non-Equilibrium Collisional Plasmas with AtomDB

    Science.gov (United States)

    Foster, Adam; Yamaguchi, H.; Smith, R. K.; Brickhouse, N. S.; Ji, L.; Kallman, T.; Wilms, J.

    2013-04-01

    Collisionally ionized plasmas that are in non-equilibrium ionization (NEI) show distinctly different emission from those in equilibrium. Recombining, or overionized, plasmas show significant recombination-driven continuum features, while ionizing plasmas show strong inner-shell emission lines, such as the Iron Kα line at 6.4-6.7keV. Existing models in analysis tools such as XSPEC treat only the equilibrium case and part of the ionizing plasma case due to a significant lack of atomic data. We present major updates to the AtomDB database, and new models for use XSPEC, which allow all types of these non-equilibrium plasmas to be modeled in a simple yet accurate fashion. This model has been created using a large amount of data obtained from published sources, supplemented by data we have calculated using the Flexible Atomic Code where required. We identify the spectral features that have been seen and can now be modeled using this data for existing missions as well as Astro-H. We also revisit archival data where recombining plasma emission has previously been identified.

  20. NON-EQUILIBRIUM ELECTRONS IN THE OUTSKIRTS OF GALAXY CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Avestruz, Camille; Nagai, Daisuke; Lau, Erwin T. [Department of Physics, Yale University, New Haven, CT 06520 (United States); Nelson, Kaylea, E-mail: camille.avestruz@yale.edu, E-mail: camille.avestruz@yale.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06520 (United States)

    2015-08-01

    The analysis of X-ray and Sunyaev–Zel’dovich measurements of the intracluster medium (ICM) assumes that electrons are in thermal equilibrium with ions in the plasma. However, in the outskirts of galaxy clusters, the electron–ion equilibration timescale can become comparable to the Hubble time, leading to systematic biases in cluster mass estimates and mass-observable scaling relations. To quantify an upper limit of the impact of non-equilibrium electrons, we use a mass-limited sample of simulated galaxy clusters taken from a cosmological simulation with a two-temperature model that assumes the Spitzer equilibration time for the electrons and ions. We show that the temperature bias is more pronounced in more massive and rapidly accreting clusters. For the most extreme case, we find that the bias is of the order of 10% at half of the cluster virial radius and increases to 40% at the edge of the cluster. Gas in filaments is less susceptible to the non-equilibrium effect, leading to azimuthal variations in the temperature bias at large cluster-centric radii. Using mock Chandra observations of simulated clusters, we show that the bias manifests in ultra-deep X-ray observations of cluster outskirts and quantify the resulting biases in hydrostatic mass and cluster temperature derived from these observations. We provide a mass-dependent fitting function for the temperature bias profile, which can be useful for modeling the effect of electron-ion equilibration in galaxy clusters.

  1. Non-equilibrium thermodynamics analysis of transcriptional regulation kinetics

    Science.gov (United States)

    Hernández-Lemus, Enrique; Tovar, Hugo; Mejía, Carmen

    2014-12-01

    Gene expression in eukaryotic cells is an extremely complex and interesting phenomenon whose dynamics are controlled by a large number of subtle physicochemical processes commonly described by means of gene regulatory networks. Such networks consist in a series of coupled chemical reactions, conformational changes, and other biomolecular processes involving the interaction of the DNA molecule itself with a number of proteins usually called transcription factors as well as enzymes and other components. The kinetics behind the functioning of such gene regulatory networks are largely unknown, though its description in terms of non-equilibrium thermodynamics has been discussed recently. In this work we will derive general kinetic equations for a gene regulatory network from a non-equilibrium thermodynamical description and discuss its use in understanding the free energy constrains imposed in the network structure. We also will discuss explicit expressions for the kinetics of a simple model of gene regulation and show that the kinetic role of mRNA decay during the RNA synthesis stage (or transcription) is somehow limited due to the comparatively low values of decay rates. At the level discussed here, this implies a decoupling of the kinetics of mRNA synthesis and degradation a fact that may become quite useful when modeling gene regulatory networks from experimental data on whole genome gene expression.

  2. Nonequilibrium Equation of State in Suspensions of Active Colloids

    Directory of Open Access Journals (Sweden)

    Félix Ginot

    2015-01-01

    Full Text Available Active colloids constitute a novel class of materials composed of colloidal-scale particles locally converting chemical energy into motility, mimicking micro-organisms. Evolving far from equilibrium, these systems display structural organizations and dynamical properties distinct from thermalized colloidal assemblies. Harvesting the potential of this new class of systems requires the development of a conceptual framework to describe these intrinsically nonequilibrium systems. We use sedimentation experiments to probe the nonequilibrium equation of state of a bidimensional assembly of active Janus microspheres and conduct computer simulations of a model of self-propelled hard disks. Self-propulsion profoundly affects the equation of state, but these changes can be rationalized using equilibrium concepts. We show that active colloids behave, in the dilute limit, as an ideal gas with an activity-dependent effective temperature. At finite density, increasing the activity is similar to increasing adhesion between equilibrium particles. We quantify this effective adhesion and obtain a unique scaling law relating activity and effective adhesion in both experiments and simulations. Our results provide a new and efficient way to understand the emergence of novel phases of matter in active colloidal suspensions.

  3. Non-Equilibrium Solidification of Undercooled Metallic Melts

    Directory of Open Access Journals (Sweden)

    Dieter M. Herlach

    2014-06-01

    Full Text Available If a liquid is undercooled below its equilibrium melting temperature an excess Gibbs free energy is created. This gives access to solidification of metastable solids under non-equilibrium conditions. In the present work, techniques of containerless processing are applied. Electromagnetic and electrostatic levitation enable to freely suspend a liquid drop of a few millimeters in diameter. Heterogeneous nucleation on container walls is completely avoided leading to large undercoolings. The freely suspended drop is accessible for direct observation of rapid solidification under conditions far away from equilibrium by applying proper diagnostic means. Nucleation of metastable crystalline phases is monitored by X-ray diffraction using synchrotron radiation during non-equilibrium solidification. While nucleation preselects the crystallographic phase, subsequent crystal growth controls the microstructure evolution. Metastable microstructures are obtained from deeply undercooled melts as supersaturated solid solutions, disordered superlattice structures of intermetallics. Nucleation and crystal growth take place by heat and mass transport. Comparative experiments in reduced gravity allow for investigations on how forced convection can be used to alter the transport processes and design materials by using undercooling and convection as process parameters.

  4. Non-equilibrium thermodynamics of harmonically trapped bosons

    Science.gov (United States)

    Ángel García-March, Miguel; Fogarty, Thomás; Campbell, Steve; Busch, Thomas; Paternostro, Mauro

    2016-10-01

    We apply the framework of non-equilibrium quantum thermodynamics to the physics of quenched small-sized bosonic quantum gases in a one-dimensional harmonic trap. We show that dynamical orthogonality can occur in these few-body systems with strong interactions after a quench and we find its occurrence analytically for an infinitely repulsive pair of atoms. We further show this phenomena is related to the fundamental excitations that dictate the dynamics from the spectral function. We establish a clear qualitative link between the amount of (irreversible) work performed on the system and the establishment of entanglement. We extend our analysis to multipartite systems by examining the case of three trapped atoms. We show the initial (pre-quench) interactions play a vital role in determining the dynamical features, while the qualitative features of the two particle case appear to remain valid. Finally, we propose the use of the atomic density profile as a readily accessible indicator of the non-equilibrium properties of the systems in question.

  5. Turbulence as a Problem in Non-equilibrium Statistical Mechanics

    Science.gov (United States)

    Goldenfeld, Nigel; Shih, Hong-Yan

    2017-05-01

    The transitional and well-developed regimes of turbulent shear flows exhibit a variety of remarkable scaling laws that are only now beginning to be systematically studied and understood. In the first part of this article, we summarize recent progress in understanding the friction factor of turbulent flows in rough pipes and quasi-two-dimensional soap films, showing how the data obey a two-parameter scaling law known as roughness-induced criticality, and exhibit power-law scaling of friction factor with Reynolds number that depends on the precise form of the nature of the turbulent cascade. These results hint at a non-equilibrium fluctuation-dissipation relation that applies to turbulent flows. The second part of this article concerns the lifetime statistics in smooth pipes around the transition, showing how the remarkable super-exponential scaling with Reynolds number reflects deep connections between large deviation theory, extreme value statistics, directed percolation and the onset of coexistence in predator-prey ecosystems. Both these phenomena reflect the way in which turbulence can be fruitfully approached as a problem in non-equilibrium statistical mechanics.

  6. Nonequilibrium transport in the pseudospin-1 Dirac-Weyl system

    Science.gov (United States)

    Wang, Cheng-Zhen; Xu, Hong-Ya; Huang, Liang; Lai, Ying-Cheng

    2017-09-01

    Recently, solid state materials hosting pseudospin-1 quasiparticles have attracted a great deal of attention. In these materials, the energy band contains a pair of Dirac cones and a flatband through the connecting point of the cones. As the "caging" of carriers with a zero group velocity, the flatband itself has zero conductivity. However, in a nonequilibrium situation where a constant electric field is suddenly switched on, the flatband can enhance the resulting current in both the linear and nonlinear response regimes through distinct physical mechanisms. Using the (2 +1 )-dimensional pseudospin-1 Dirac-Weyl system as a concrete setting, we demonstrate that, in the weak field regime, the interband current is about twice larger than that for pseudospin-1/2 system due to the interplay between the flatband and the negative band, with the scaling behavior determined by the Kubo formula. In the strong field regime, the intraband current is √{2 } times larger than that in the pseudospin-1/2 system, due to the additional contribution from particles residing in the flatband. In this case, the current and field follow the scaling law associated with Landau-Zener tunneling. These results provide a better understanding of the role of the flatband in nonequilibrium transport and are experimentally testable using electronic or photonic systems.

  7. Non-Equilibrium Turbulence and Two-Equation Modeling

    Science.gov (United States)

    Rubinstein, Robert

    2011-01-01

    Two-equation turbulence models are analyzed from the perspective of spectral closure theories. Kolmogorov theory provides useful information for models, but it is limited to equilibrium conditions in which the energy spectrum has relaxed to a steady state consistent with the forcing at large scales; it does not describe transient evolution between such states. Transient evolution is necessarily through nonequilibrium states, which can only be found from a theory of turbulence evolution, such as one provided by a spectral closure. When the departure from equilibrium is small, perturbation theory can be used to approximate the evolution by a two-equation model. The perturbation theory also gives explicit conditions under which this model can be valid, and when it will fail. Implications of the non-equilibrium corrections for the classic Tennekes-Lumley balance in the dissipation rate equation are drawn: it is possible to establish both the cancellation of the leading order Re1/2 divergent contributions to vortex stretching and enstrophy destruction, and the existence of a nonzero difference which is finite in the limit of infinite Reynolds number.

  8. Dispersion compensation in Fourier domain optical coherence tomography using the fractional Fourier transform.

    Science.gov (United States)

    Lippok, Norman; Coen, Stéphane; Nielsen, Poul; Vanholsbeeck, Frédérique

    2012-10-08

    We address numerical dispersion compensation based on the use of the fractional Fourier transform (FrFT). The FrFT provides a new fundamental perspective on the nature and role of group-velocity dispersion in Fourier domain OCT. The dispersion induced by a 26 mm long water cell was compensated for a spectral bandwidth of 110 nm, allowing the theoretical axial resolution in air of 3.6 μm to be recovered from the dispersion degraded point spread function. Additionally, we present a new approach for depth dependent dispersion compensation based on numerical simulations. Finally, we show how the optimized fractional Fourier transform order parameter can be used to extract the group velocity dispersion coefficient of a material.

  9. Morphological instability of a non-equilibrium ice-colloid interface

    KAUST Repository

    Peppin, S. S. L.

    2009-10-02

    We assess the morphological stability of a non-equilibrium ice-colloidal suspension interface, and apply the theory to bentonite clay. An experimentally convenient scaling is employed that takes advantage of the vanishing segregation coefficient at low freezing velocities, and when anisotropic kinetic effects are included, the interface is shown to be unstable to travelling waves. The potential for travelling-wave modes reveals a possible mechanism for the polygonal and spiral ice lenses observed in frozen clays. A weakly nonlinear analysis yields a long-wave evolution equation for the interface shape containing a new parameter related to the highly nonlinear liquidus curve in colloidal systems. We discuss the implications of these results for the frost susceptibility of soils and the fabrication of microtailored porous materials. © 2009 The Royal Society.

  10. Thermal transport through a spin-phonon interacting junction: A nonequilibrium Green's function method study

    Science.gov (United States)

    Zhang, Zu-Quan; Lü, Jing-Tao

    2017-09-01

    Using the nonequilibrium Green's function method, we consider heat transport in an insulating ferromagnetic spin chain model with spin-phonon interaction under an external magnetic field. Employing the Holstein-Primakoff transformation to the spin system, we treat the resulted magnon-phonon interaction within the self-consistent Born approximation. We find the magnon-phonon coupling can change qualitatively the magnon thermal conductance in the high-temperature regime. At a spectral mismatched ferromagnetic-normal insulator interface, we also find thermal rectification and negative differential thermal conductance due to the magnon-phonon interaction. We show that these effects can be effectively tuned by the external applied magnetic field, a convenient advantage absent in anharmonic phonon and electron-phonon systems studied before.

  11. Dynamics of charge transfer: rate processes formulated with nonequilibrium Green's functions.

    Science.gov (United States)

    Yeganeh, Sina; Ratner, Mark A; Mujica, Vladimiro

    2007-04-28

    The authors examine the connection between electron transport under bias in a junction and nonadiabatic intramolecular electron transfer (ET). It is shown that under certain assumptions it is possible to define a stationary current that allows the computation of the intramolecular transfer rate using the same formalism that is employed in the description of transport. They show that the nonequilibrium Green's function formalism of quantum transport can be used to calculate the ET rate. The formal connection between electron transport and electron transfer is made, and they work out the simple case of an electronic level coupled to a vibrational mode representing a thermal bath and show that the result is the same as expected from a Fermi golden rule treatment, and in the high-temperature limit yields the Marcus electron transfer theory. The usefulness of this alternative formulation of rates is discussed.

  12. Non-equilibrium phase-transitions in multi-component Rydberg gases

    CERN Document Server

    Ding, D S; Shi, B S; Guo, G C

    2016-01-01

    Highly-excited Rydberg atoms have strong long-range interactions resulting in exotic optical prop erties such as large single photon non-linearities and intrinsic bistability. In this paper we study optical-driven non-equilibrium phase transitions in a thermal Rydberg gas with a sensitivity two order of magnitude higher than in previous work. In this regime we can elucidate the effect of inter actions on the bistable optical response, and exploit different branches in the potential in order to study multi-component Rydberg gases with a rich of phase diagram including overlapping bistable regions. In addition, we study the effect of polarization on the width of the hysteresis loop. Finally, we observe that the medium exhibits a dynamical instability resulting from the competing dynamics of excitation and decay.

  13. Validation of Fourier analysis of videokeratographic data.

    Science.gov (United States)

    Sideroudi, Haris; Labiris, Georgios; Ditzel, Fienke; Tsaragli, Efi; Georgatzoglou, Kimonas; Siganos, Haralampos; Kozobolis, Vassilios

    2017-06-15

    The aim was to assess the repeatability of Fourier transfom analysis of videokeratographic data using Pentacam in normal (CG), keratoconic (KC) and post-CXL (CXL) corneas. This was a prospective, clinic-based, observational study. One randomly selected eye from all study participants was included in the analysis: 62 normal eyes (CG group), 33 keratoconus eyes (KC group), while 34 eyes, which had already received CXL treatment, formed the CXL group. Fourier analysis of keratometric data were obtained using Pentacam, by two different operators within each of two sessions. Precision, repeatability and Intraclass Correlation Coefficient (ICC), were calculated for evaluating intrassesion and intersession repeatability for the following parameters: Spherical Component (SphRmin, SphEcc), Maximum Decentration (Max Dec), Regular Astigmatism, and Irregularitiy (Irr). Bland-Altman analysis was used for assessing interobserver repeatability. All parameters were presented to be repeatable, reliable and reproductible in all groups. Best intrasession and intersession repeatability and reliability were detected for parameters SphRmin, SphEcc and Max Dec parameters for both operators using ICC (intrasession: ICC > 98%, intersession: ICC > 94.7%) and within subject standard deviation. Best precision and lowest range of agreement was found for the SphRmin parameter (CG: 0.05, KC: 0.16, and CXL: 0.2) in all groups, while the lowest repeatability, reliability and reproducibility was detected for the Irr parameter. The Pentacam system provides accurate measurements of Fourier tranform keratometric data. A single Pentacam scan will be sufficient for most clinical applications.

  14. Study on the Effects of Thermal Aging on Insulating Paper for High Voltage Transformer Composite with Natural Ester from Palm Oil Using Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDS)

    National Research Council Canada - National Science Library

    Abi Munajad; Cahyo Subroto

    2017-01-01

    Mineral oil is widely used as liquid insulation in high voltage equipment. Due to environmental considerations, recently natural esters have been considered as naturally friendly liquid insulation candidates for high voltage transformers...

  15. Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

    Science.gov (United States)

    Kjørstad, Åsmund; Corteville, Dominique M R; Fischer, Andre; Henzler, Thomas; Schmid-Bindert, Gerald; Zöllner, Frank G; Schad, Lothar R

    2014-08-01

    To quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation- and perfusion-related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow-ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method. The standard FD perfusion images are quantified by comparing the partially blood-filled pixels in the lung parenchyma with the fully blood-filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced-MRI. All pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF-FD = 150 mL/min/100 mL, mean PBF-SEEPAGE = 151 mL/min/100 mL). The Bland-Altman plot shows a good spread of values, indicating no systematic bias between the methods. Quantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Copyright © 2013 Wiley Periodicals, Inc.

  16. Deploying Fourier Coefficients to Unravel Soybean Canopy Diversity.

    Science.gov (United States)

    Jubery, Talukder Z; Shook, Johnathon; Parmley, Kyle; Zhang, Jiaoping; Naik, Hsiang S; Higgins, Race; Sarkar, Soumik; Singh, Arti; Singh, Asheesh K; Ganapathysubramanian, Baskar

    2016-01-01

    Soybean canopy outline is an important trait used to understand light interception ability, canopy closure rates, row spacing response, which in turn affects crop growth and yield, and directly impacts weed species germination and emergence. In this manuscript, we utilize a methodology that constructs geometric measures of the soybean canopy outline from digital images of canopies, allowing visualization of the genetic diversity as well as a rigorous quantification of shape parameters. Our choice of data analysis approach is partially dictated by the need to efficiently store and analyze large datasets, especially in the context of planned high-throughput phenotyping experiments to capture time evolution of canopy outline which will produce very large datasets. Using the Elliptical Fourier Transformation (EFT) and Fourier Descriptors (EFD), canopy outlines of 446 soybean plant introduction (PI) lines from 25 different countries exhibiting a wide variety of maturity, seed weight, and stem termination were investigated in a field experiment planted as a randomized complete block design with up to four replications. Canopy outlines were extracted from digital images, and subsequently chain coded, and expanded into a shape spectrum by obtaining the Fourier coefficients/descriptors. These coefficients successfully reconstruct the canopy outline, and were used to measure traditional morphometric traits. Highest phenotypic diversity was observed for roundness, while solidity showed the lowest diversity across all countries. Some PI lines had extraordinary shape diversity in solidity. For interpretation and visualization of the complexity in shape, Principal Component Analysis (PCA) was performed on the EFD. PI lines were grouped in terms of origins, maturity index, seed weight, and stem termination index. No significant pattern or similarity was observed among the groups; although interestingly when genetic marker data was used for the PCA, patterns similar to canopy

  17. Fourier Plane Image Combination by Feathering

    Science.gov (United States)

    Cotton, W. D.

    2017-09-01

    Astronomical objects frequently exhibit structure over a wide range of scales whereas many telescopes, especially interferometer arrays, only sample a limited range of spatial scales. To properly image these objects, images from a set of instruments covering the range of scales may be needed. These images then must be combined in a manner to recover all spatial scales. This paper describes the feathering technique for image combination in the Fourier transform plane. Implementations in several packages are discussed and example combinations of single dish and interferometric observations of both simulated and celestial radio emission are given.

  18. Fourier-transforming with quantum annealers

    Directory of Open Access Journals (Sweden)

    Itay eHen

    2014-07-01

    Full Text Available We introduce a set of quantum adiabatic evolutions that we argue may be used as `building blocks', or subroutines, in the onstruction of an adiabatic algorithm that executes Quantum Fourier Transform (QFT with the same complexity and resources as its gate-model counterpart. One implication of the above construction is the theoretical feasibility of implementing Shor's algorithm for integer factorization in an optimal manner, and any other algorithm that makes use of QFT, on quantum annealing devices. We discuss the possible advantages, as well as the limitations, of the proposed approach as well as its relation to traditional adiabatic quantum computation.

  19. Fourier analysis of real-world data

    Science.gov (United States)

    Johnson, Michael L.; Straume, Martin

    1997-05-01

    Biological time-series data pertaining to human circadian and ultradian hormonal rhythms are often short, sparse, irregularly spaced, and noisy. In addition, they often have missing data points and have variable experimental uncertainties. The objective of collecting and analyzing such data is to find the amplitude, phase, and period of the primary rhythmic component contained within the data. Often the question is simply: Does a rhythm exist. The theoretical aspects of some Fourier techniques are discussed, including methods for detrending non-stationary time-series and the evaluation of confidence intervals. Analysis of typical biological data are also presented.

  20. Fourier transforms in the complex domain

    CERN Document Server

    Wiener, N

    1934-01-01

    With the aid of Fourier-Mellin transforms as a tool in analysis, the authors were able to attack such diverse analytic questions as those of quasi-analytic functions, Mercer's theorem on summability, Milne's integral equation of radiative equilibrium, the theorems of Münz and Szász concerning the closure of sets of powers of an argument, Titchmarsh's theory of entire functions of semi-exponential type with real negative zeros, trigonometric interpolation and developments in polynomials of the form \\sum^N_1A_ne^{i\\lambda_nx}, lacunary series, generalized harmonic analysis in the complex domain,