High-energy cosmic-ray electrons and positrons (CREs), which lose energy quickly during their propagation, provide a probe of Galactic high-energy processes and may enable the observation of phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been measured directly up to approximately 2 teraelectronvolts in previous balloon- or space-borne experiments, and indirectly up to approximately 5 teraelectronvolts using ground-based Cherenkov γ-ray telescope arrays. Evidence for a spectral break in the teraelectronvolt energy range has been provided by indirect measurements, although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range 25 gigaelectronvolts to 4.6 teraelectronvolts by the Dark Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The largest part of the spectrum can be well fitted by a 'smoothly broken power-law' model rather than a single power-law model. The direct detection of a spectral break at about 0.9 teraelectronvolts confirms the evidence found by previous indirect measurements, clarifies the behaviour of the CRE spectrum at energies above 1 teraelectronvolt and sheds light on the physical origin of the sub-teraelectronvolt CREs.

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1 / 2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at~300 GeV found by previous experiments and reveals a softening at~13.6 TeV, with the spectral index changing from~2.60 to~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

A new catalytic system was developed for the selective conversion of biomass-derived furfural to cyclopentanone in aqueous solution. CuZnAl catalysts with different Cu/Zn molar ratios (0.5, 1, 2, and 3) and calcination temperatures (350, 500, and 700 °C) were investigated, and the CuZnAl-500−0.5 catalyst (Cu/Zn = 0.5, calcined at 500 °C) showed a remarkable catalytic performance in the reaction. A 62% yield of cyclopentanone was obtained at the optimized conditions (150 °C, 4 MPa H 2 , 6 h), and the TOF was 9.4 h −1 . The catalysts were characterized by nitrogen adsorption, XRD, TEM, N 2 O titration, ICP, XPS, and a carbon−sulfur analyzer. The factors that influenced the activity of catalysts were also investigated. Additionally, the CuZnAl-500−0.5 was recycled five times and maintained good activity and stability. Hence, the current work presents a new and efficient catalytic system for the conversion of furfural to cyclopentanone. The low-cost nature of the CuZnAl makes it a potential catalyst for the production of cyclopentanone in industry.

Two sets of hydroxyphenyl-benzothiazole based compounds, which exhibited emission colors across the entire visible spectrum for both photoluminescence and electroluminescence, have been designed and synthesized.

Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer (DAMPE) is a satellite-based cosmic-ray experiment that is operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 316 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at ∼600 GeV has been observed, along with a softening at ∼29 TeV measured with a 6.6σ significance. Moreover, by measuring the energy spectrum up to 316 TeV, a strong link is established between space-and ground-based experiments, also suggesting the presence of a second hardening at ∼150 TeV. * https://geant4.web.cern.ch/node/302 † https://web.ikp.kit.edu/rulrich/crmc.html