The design and construction of a high-performance, low-cost, and easy to assemble adiabatic extension set for homebuilt and commercial spectrometers is described. Described apparatus set was designed for the fast adiabatic passage generation and is based on direct digital synthesizer DDS. This solution gives generator high signal to noise ratio, phase stability even during frequency change which is only possible in expansive commercial high-end hardware. Critical synchronization and timing issues are considered and solutions are discussed. Different experimental conditions and techniques for the measurements are briefly discussed. The proposed system is very flexible and might be used for the measurement of low-frequency nuclear magnetic resonance.
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http://dx.doi.org/10.1007/s00723-012-0372-3 | DOI Listing |
Eur Heart J Imaging Methods Pract
January 2025
A.I. Virtanen Institute, University of Eastern Finland, Neulaniementie 2, 70210 Kuopio, Finland.
Aims: The aim of this study was to develop an ultra-short echo time 3D magnetic resonance imaging (MRI) method for imaging subacute myocardial infarction (MI) quantitatively and in an accelerated way. Here, we present novel 3D T- and T -weighted Multi-Band SWeep Imaging with Fourier Transform and Compressed Sensing (MB-SWIFT-CS) imaging of subacute MI in mice hearts .
Methods And Results: Relaxation time-weighted and under-sampled 3D MB-SWIFT-CS MRI were tested with manganese chloride (MnCl) phantom and mice MI model.
J Chem Phys
January 2025
Division of Energy, Matter and Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA.
Developing efficient path integral (PI) methods for atomistic simulations of vibrational spectra in heterogeneous condensed phases and interfaces has long been a challenging task. Here, we present the h-CMD method, short for hybrid centroid molecular dynamics, which combines the recently introduced fast quasi-CMD (f-QCMD) method with fast CMD (f-CMD). In this scheme, molecules that are believed to suffer more seriously from the curvature problem of CMD, e.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, 295 Viale Regina Elena, I-00161 Roma, Italy.
Polymers (Basel)
October 2024
Departament de Física de la Matèria Condensada (FMC), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain.
We study the enhancement of the elastocaloric effect in natural rubber by using forced air convection to favour heat extraction during the elongation stage of a stretching-unstretching cycle. Elastocaloric performance is quantified by means of the adiabatic undercooling that occurs after fast removal of the stress, measured by infrared thermography. To ensure accuracy, spatial averaging on thermal maps of the sample surface is performed since undercooled samples display heterogeneities caused by various factors.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
February 2025
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
Conformational dynamics has been well observed in the 3s Rydberg state of amines, whereas its observation in higher-energy, non-equilibrium 3p Rydberg states is very rare, especially for a reversible conformational transition that could compete with other non-adiabatic transitions. Herein, we report the observation of a reversible conformational interconversion phenomenon in the 3p Rydberg excited-state dynamics of N,N-dimethylethylamine (DMEA). Upon electronic excitation, a forward and backward interconversion between the initially prepared 3p_l and 3p_h conformers accompanied by 3p internal conversions occurs, resulting in a 3p_l/3p_h equilibrium ratio of 61 %/39 % within ∼1.
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