We present the design of a velocity map imaging spectrometer where the target gas is injected from a capillary that is integrated in the repeller plate of the ion optics assembly that drives electrons/ions formed by ionization or dissociation to a two-dimensional detector. The geometry of this design allows the use of gas densities in the interaction region that are two to three orders of magnitude higher than the densities that are used in standard velocity map imaging spectrometers, making the detector suitable for working with weak light sources such as newly developed attosecond pulse sources, or (quasi-)cw sources such as synchrotrons. In a test where monoenergetic photoelectrons were generated by six-photon ionization of Xe (utilizing the second harmonic of a neodymium doped Nd:YAG), the kinetic energy resolution of the spectrometer was found to be DeltaE/E=1.8%. This number was found to be in good agreement with Monte Carlo simulations.
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http://dx.doi.org/10.1063/1.3085799 | DOI Listing |
Sensors (Basel)
January 2025
College of Computer, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
Gesture recognition technology based on millimeter-wave radar can recognize and classify user gestures in non-contact scenarios. To address the complexity of data processing with multi-feature inputs in neural networks and the poor recognition performance with single-feature inputs, this paper proposes a gesture recognition algorithm based on esNet ong Short-Term Memory with an ttention Mechanism (RLA). In the aspect of signal processing in RLA, a range-Doppler map is obtained through the extraction of the range and velocity features in the original mmWave radar signal.
View Article and Find Full Text PDFSci Rep
January 2025
Agricultural Engineering Department, Faculty of Agriculture and Natural Resources, Aswan University, Aswan, Egypt.
The experiments were conducted at different levels of infrared power, airflow, and temperature. The relationships between the input process factors and response factors' physicochemical properties of dried garlic were optimized by a self-organizing map (SOM), and the model was developed using machine learning. Artificial Neural Network (ANN) with 99% predicting accuracy and Self-Organizing Maps (SOM) with 97% clustering accuracy were used to determine the quality characteristics of garlic.
View Article and Find Full Text PDFNature
January 2025
Innovative Genomics Institute, University of California Berkeley, Berkeley, CA, USA.
Rubisco is the primary CO-fixing enzyme of the biosphere, yet it has slow kinetics. The roles of evolution and chemical mechanism in constraining its biochemical function remain debated. Engineering efforts aimed at adjusting the biochemical parameters of rubisco have largely failed, although recent results indicate that the functional potential of rubisco has a wider scope than previously known.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200438, China.
Understanding the interactions between transition metal atoms and molecules is important for the study of various related chemical and physical processes. In this study, we have investigated collisions between iron (Fe), iridium (Ir), and platinum (Pt) and the small molecules CH, O, and CO using a crossed-beam and time-sliced ion velocity map imaging technique. Elastic collisions were observed in all cases, except for collisions of Pt with O and CO.
View Article and Find Full Text PDFPM R
January 2025
Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA.
Background: Individuals with spinal cord injury (SCI) commonly have autonomic dysreflexia (AD) with increased sympathetic activity. After SCI, individuals have decreased baroreflex sensitivity and increased vascular responsiveness.
Objective: To evaluate the relationship between baroreflex and blood vessel sensitivity with AD symptoms.
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