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Fast Fourier Transform periodic interpolation method for superposition sums in a periodic unit cell
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Impact of Flow Configurations on Response Time and Data Quality in Real-Time, In-Line Fourier Transform Infrared (FTIR) Monitoring of Viscous Flows
The real-time, in-line monitoring of continuous flow concentrations is widely conducted via infrared (IR) spectrometry by using a flow cell connected to a reactive flow stream. For protective purposes, the IR sensor tip is typically offset from the flow. This offset can cause the formation of a stagnant boundary layer above the sensor, especially when dealing with high-viscosity fluids. As a result, the IR signal response time is often controlled by the slow diffusional exchange of fluid in the boundary layer, as confirmed via 2D computational fluid dynamics (CFD) simulations. We evaluated several flow configuration modifications in a typical IR flow cell in order to identify the changes to the flow dynamics that enable improved response times with minimal changes to the cell configuration: the use of (i) vertical flow, where the standard horizontal flow over the sensor is redirected to contact vertically with the sensor, (ii) a static mixer to create radial flow momentum above the IR sensor, and (iii) horizontal or vertical nozzles to direct the flow toward the IR sensor. The vertical flow configuration did not show any significant improvement over the standard horizontal flow configuration. However, the static mixer, horizontal nozzle, and vertical nozzle configurations all resulted in markedly improved response times and signal quality, albeit at the expense of a higher pressure drop across the flow cell. These results point toward straightforward, user-accessible modifications of in-line IR flow cells that result in significant improvements in signal stability and acquisition times.
Benchmarking a Proof-of-Concept Performance Portable SYCL-based Fast Fourier Transformation Library
ABSTRACT In this paper, we present an early version of a SYCL-based FFT library, capable of running on all major vendor hardware, including CPUs and GPUs from AMD, ARM, Intel and NVIDIA. The current limitations of our library is it supports single-dimension FFTs up to 211 in length and base-2 input sequences. Although preliminary, the aim of this work is to seed further developments for a rich set of features for calculating FFTs. The library has the advantage over existing portable FFT libraries in that it is single-source, and there- fore removes the complexities that arise due to abundant use of pre-processor macros and auto-generated kernels to target different architectures. We exercise two SYCL-enabled compilers, Codeplay ComputeCpp and Intel's open-source LLVM project, to evaluate performance portability of our SYCL-based FFT on various hetero- geneous architectures.We provide studies comparing our portable library with highly optimized vendor-specific FFT libraries, and discuss potential sources hindering performance.
Single-shot large field of view Fourier transform holography with a picosecond plasma-based soft X-ray laser
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Wave-Optics Simulation Framework of Fourier Transform Holography with XMCD
We present a wave-optics simulation framework, implemented within the SRW, for modeling FTH with XMCD contrast. The framework propagates coherent, circularly polarized X-ray wavefronts from an undulator source through the sample and optics to the detector, reconstructing real-space images from the resulting holograms. Three principal extensions are introduced: (i) incorporation of polarization-dependent refractive indices in the sample plane, enabling direct simulation of XMCD contrast, (ii) a memory-efficient wavefront-splitting propagation scheme that treats individual apertures independently and coherently combines their fields at detector, and (iii) an integrated reconstruction module that delivers holographic images within the same framework. Together, these advances establish a versatile tool for quantitative exploration of coherence, aperture geometry, and detector sampling, and for the design and interpretation of XMCD-FTH experiments at synchrotron beamlines.
Quantum Fourier Transform with Leakage Control
In circuit QED (cQED) systems, one can manipulate the cavity Fock states to use quantum processing unit (QPU). Since the coherence times of the Fock states are long, qudit based computation can be possible. One of the most basic gate that can be engineered in this cQED platform is the displacement gate, $D(\alpha)$. However, accessible number of qudit-levels is finite. The truncated displacement gate on the qudit is the source of theoretical error above the logical states and needs to be addressed. In this work, we monitor and minimize the leakage in qudit systems that involves displacement gate by introducing so-called `bumper' states and a modified cost function.
Orbiting Carbon Observatory-2 (OCO-2) Fourier Transform Spectrometer Validation: Lamont, Oklahoma Interim Field Campaign Report
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The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder I. The Spectral Feature Finder and Catalogue
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Insights on Structure and Threshold Detection Limits of Stichtite (Magnesium-Chromium Carbonate-Hydroxide) by Fourier Transform Infrared Analysis
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Determination of mid-infrared refractive indices of superconducting thin films using Fourier transform infrared spectroscopy
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A new holographic method for a posteriori image-deblurring restoration of ordinary photographs using ''extended-source'' lensless Fourier-transform holography compensation.
Holographic optical computing image restoration method for a posteriori deblurring of photographs