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.

Electronic structures of zigzag edged graphene nanoribbons (ZGNRs) doped with boron (B) or nitrogen (N) atoms are investigated by spin polarized first-principles calculations. We find that ZGNRs can be tuned to be either semiconducting, half-metallic, or metallic by controlling the distance of the impurity atoms to the edges. A new scheme is identified to achieve full half-metallicity in ZGNRs by doping B atom at one edge and N atom at the other. We find that the origin of the half-metallicity is due to interaction between the edge states and B/N atoms which results in direct control over the electron occupation of the edge states. This mechanism is so robust that full half-metallicity can always be produced in ZGNRs irrespective of the ribbon width, which opens new possibilities for applications of ZGNRs in spintronic devices.

These data provide novel insight to the organo-specific release/uptake of acylcarnitines. The liver is a major contributor to systemic short chain acylcarnitines, whereas the muscle tissue releases mostly medium chain acylcarnitines during exercise, indicating that other tissues are contributing to the systemic increase in long chain acylcarnitines.

The dihydrogenation effects in the zigzag-edged graphene nanoribbons (ZGNRs) have been systematically investigated by first-principles calculations. Due to the dihydrogenation, the edges effectively turn to the so-called Klein edges, which results in localized edge states in (0, 2 3 π) and extended bulk states in (2 3 π,π). Compared with monohydrogenation, the edge magnetic moment is substantially increased and the edge states get much more delocalized, which results in the most attractive observation that the energy difference between the antiferromagnetic (AFM) and ferromagnetic (FM) configurations is greatly increased by nearly one order of magnitude from the general several meV and thus the AFM ground state of certain ZGNRs becomes stable at room temperature. This suggests that the dihydrogenated ZGNRs are more promising than monohydrogenated ones for spintronic devices. Our finding provides an enlighening hint for stablizing the ground AFM state in ZGNRs.

Spectrum-energy correlations of peak energy with total prompt γ-ray emission energies, namely E E p i iso,g , and E L p i p , -, had been studied for long gamma-ray bursts (GRBs) previously by many authors. These energy correlations were proposed to measure the universe and classify GRBs as useful probes. However, most of these relations were built by non-Swift bursts. The spectrum-energy correlations of short bursts have not been systematically established yet; in particular, how the newly found GRB170817A matches these energy relations is unknown to date. We will first refresh the three spectrum-energy relations of Swift/BAT and Fermi/GBM long bursts and build the corresponding relations of short bursts. Then, we confirm whether they are commonly available as a discriminator of short and long GRBs. Some potential violators to these relations will be investigated. Combining with the plane of peak energy versus fluence, we select 31 short and 252 long GRBs with well-measured peak energy and redshift to study the issue of GRB classifications connected with the above energy relations statistically. We find that the three energy relations do exist in our new GRB samples and they are marginally consistent with some previous results. We report for the first time that short GRBs hold the three corresponding energy relations having the consistent power-law indices with long GRBs. It is found that these energy relations can be adopted to discriminate GRBs successfully if they are put in the peak energy versus fluence plane. Excitingly, we point out that GRB090510 matches the energy relations of E E p i iso ,and E L p i p , -, but violates the E E p i ,g relation. More excitingly, we find that GRB170817A is an outlier to all the three energy correlations.

We have investigated the electronic and magnetic properties of Co- and Fe-doped SnO2 by first-principles methods. The obtained results show that the ferromagnetic order is energetically much favored relative to the antiferromagnetic order in all the considered models of Co- and Fe-doped SnO2. The exchange interaction between Co ions is a long-range ferromagnetic interaction and gradually weakened as the distance between Co ions increases. For Fe-doped SnO2, the exchange interaction is also a long-range ferromagnetic one, but it oscillates with the variation of the distances between Fe ions. In addition, we further probe the concentration effect on the magnetic properties in the doped systems. The obtained results show that the exchange interaction between Co and Fe ions is reduced, implying that the enhancement of Curie temperature is not favored by increasing Co- and Fe-doping concentrations.

The object of this study was to investigate the effect of two altitudes (1600 vs. 3600 m) with two nutritional levels [5.88 MJ/kg dry matter (DM) vs. 7.56 MJ/kg DM] on apparent total tract digestibility, rumen fermentation, energy metabolism, milk yield and milk composition in Chinese Holstein cows. Sixteen Chinese Holstein cows in their third lactation with close body weights, days in milk and milk yield were randomly divided into four groups, of which two were directly transferred from Lanzhou (altitude of 1600 m) to Lhasa (altitude of 3600 m). Four treatments (high plateau and high nutrition level, HA-HN; high plateau and low nutrition level, HA-LN; low plateau and high nutrition level, LA-HN; and low plateau and low nutrition level, LA-LN) were randomly arranged in a 2 × 2 factorial experimental design. Results indicated that the apparent total tract digestibility of a diet's DM, organic matter, crude protein, neutral detergent fibre and acid detergent fibre and DM intake were not affected by either altitude or nutrition level (p > 0.05). Milk protein percentage was higher for the diet with the high level of nutrition than for the diet with low nutrition level irrespective of altitude (p < 0.05). Percentages of milk fat and milk lactose were not affected by either altitude or nutrition level (p > 0.05). The metabolizable energy used for milk energy output was decreased by high altitude in comparison with that at low altitude (p < 0.05). No differences were observed in the live body weight or body condition score (BCS) of Chinese Holstein cows among all of the four treatments (p > 0.05).

DArk Matter Particle Explorer (DAMPE), the satellite-based cosmic ray and gamma ray measurement experiment, relies on its calorimeter to measure the energy of incident particles. The calorimeter adopts crystals of bismuth germanium oxide (BGO) as scintillating material, and it is designed to aim for measurements of energy ranging from 50 GeV to 100 TeV in the case of a cosmic ray nucleus. This work concerns the response of the BGO calorimeter to nucleus-type cosmic rays. Cosmic rays with very low energy can rarely reach the detector due to the Earth's magnetic field. A cutoff on lower energy can be observed in the energy spectrum. In this work, the cutoff is used to study the response of the calorimeter. Carbon, neon, silicon and iron are analyzed separately in comparison with Monte Carlo simulations by Geant4.