At the University of Frankfurt a high current proton source has been developed and tested for the FRANZ-Project [U. Ratzinger, L. P. Chau, O. Meusel, A. Schempp, K. Volk, M. Heil, F. Käppeler, and R. Stieglitz, "Intense pulsed neutron source FRANZ in the 1-500 keV range," ICANS-XVIII Proceedings, Dongguan, April 2007, p. 210]. The ion source is a filament driven arc discharge ion source. The new design consists of a plasma generator, equipped with a filter magnet to produce nearly pure proton beams (92 %), and a compact triode extraction system. The beam current density has been enhanced up to 521 mA/cm(2). Using an emission opening radius of 4 mm, a proton beam current of 240 mA at 50 keV beam energy in continuous wave mode (cw) has been extracted. This paper will present the current status of the proton source including experimental results of detailed investigations of the beam composition in dependence of different plasma parameters. Both, cw and pulsed mode were studied. Furthermore, the performance of the ion source was studied with deuterium as working gas.
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Angew Chem Int Ed Engl
January 2025
Yunnan University, Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education, East Outer Ring Road, 650500, Kunming, CHINA.
The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiol-catalyzed hydrogen atom transfer process.
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January 2025
Department of Physics, University of California, Merced, Merced, CA, USA.
Metal halide perovskite (MHP) solar cells are promising aerospace power sources given their potential as inexpensive, lightweight, and resilient solar electricity generators. Herein, the intrinsic radiation tolerance of unencapsulated methylammonium lead iodide/chloride (CHNHPbICl) films was isolated. Spatially resolved photoluminescence (PL) spectroscopy and confocal microscopy revealed the fundamental defect physics through optical changes as films were irradiated with 4.
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January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
Lytic polysaccharide monooxygenases (LPMOs) are a unique group of monocopper enzymes that exhibit remarkable ability to catalyze the oxidative cleavage of recalcitrant carbohydrate substrates, such as cellulose and chitin, by utilizing O or HO as the oxygen source. One of the key challenges in understanding the catalytic mechanism of LPMOs lies in deciphering how they activate dioxygen using diverse reductants. To shed light on this intricate process, we conducted in-depth investigations using quantum mechanical/molecular mechanical (QM/MM) metadynamics simulations, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations.
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January 2025
Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Bacterial levans are biopolymers composed of fructose units linked by β-2,6 glycosidic bonds that are degradable, nontoxic and flexible, representing a green technology with significant applications across various industries. Fermented soybeans are a common source of bacteria-producing polysaccharides. In this study, KKSB4, KKSB6 and KKSB7 isolated from traditionally fermented soybean (Thua-nao), along with strain 5.
View Article and Find Full Text PDFFood Chem
January 2025
Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100 Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland. Electronic address:
Waste produced during cultivation of edible plants can be a valuable source of bioactive molecules. Herein, we present the valorization of tomato leaves to obtain biologically active extracts. Deep eutectic solvents (DESs), composed of natural ingredients, were applied as extracting solvents.
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