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Nuclear astrophysics is an interdisciplinary subject of nuclear physics and astrophysics. As the forefront of fundamental research, it has played an important role in the process of deepening understanding of the universe and stellar evolution. One of the primary tasks of nuclear astrophysics is the precise measurement of the cross-sections of the thermonuclear reactions which are responsible for stellar evolution and the synthesis of the chemical elements. Deep underground laboratory, where the flux of cosmic muons is reduced by several orders of magnitude, provides a great opportunity of conducting the measurements of the crucial reaction cross section directly within their Gamow energy regions. At present, there are three ongoing underground nuclear astrophysics experiments, including LUNA in National Laboratory of Gran Sasso (LNGS), CASPER in Sanford Underground Research Facility (SURF), and Jinping Underground Nuclear Astrophysics (JUNA) in China Jinping Underground Laboratory (CJPL). As a pioneer, LUNA has carried out experimental research on several key reactions in the last three decades. LUNA’s result deepens our understanding of the properties of the neutrino, of the sun, and of the universe itself. Recently, with the development of CASPAR and JUNA, the underground experiment has breathed new life. JUNA project is carried out in the second phase of CJPL (CJPL-Ⅱ). CJPL was built under Jinping Mountain with 2 400 m of rock overburden (6 720 m of water equivalent, m.w.e.) leading to the muon flux, the most penetrating component of the cosmic rays, is about 100 times lower compared with LNGS and SURF. More importantly, JUNA has developed a 400 kV intense current accelerator, the beam intensity is more than 10 times that of LUNA. Corresponding underground measurement techniques have also been developed. With the advantage of the ultra-low background of CJPL-Ⅱ and intense beam current at mA level, JUNA’s experimental platform becomes the underground accelerator facility with the highest measurement accuracy in the world. In 2021, JUNA started its first campaign of experimental measurements. Within the 4-month of operation, JUNA measured several important reaction cross sections for the studies of hydrostatic hydrogen and helium burnings, including 25Mg(p, γ)26Al, 19F(p, αγ)16O, 19F(p, γ)16O, 13C(α, n)16O, 18O(α, γ)22Ne and 12C(α, γ)16O reactions. JUNA’s experiments achieved the lowest energy and the highest accuracy in all the above measurements, bringing the underground nuclear astrophysics experiment into a new stage. After nearly a century of development, people have a deeper understanding of stellar evolution and the synthesis of chemical elements. In particular, the deep underground experiment has brought nuclear astrophysics into a new stage of accurate measurement. However, there are still many mysteries to be resolved in nuclear astrophysics. For example, the most important reaction 12C(α, γ)16O, known as the “Holy Grail”, still has no accurate cross-section data in its Gamow window. Looking to the future, measurements over a wider energy range and with higher beam current intensity will be the development direction of underground nuclear astrophysics experiments. Now CASPAR has temporarily withdrawn from SURF due to laboratory construction, and improving the accelerator beam intensity will be its primary task for future restarts. LUNA-MV accelerator is in the commissioning phase at LNGS, and its high voltage reaches 3.5 MV. JUNA also proposed a new plan, which will be focused on improving beam intensity and developing new underground techniques to maintain the advantage of measurement accuracy. With the new plan, JUNA will continue to occupy a dominant position in underground nuclear astrophysics experiments. The future of underground nuclear astrophysics experiments can be expected.

Pulsed signal trains comprising clicks, buzzes, and burst-pulses play important roles in the life activities of odontocetes, but they have not been distinguished in Indo-Pacific humpback dolphins. Underwater vocalizations of this species were recorded from 27 September to 2 October 2019 in the Beibu Gulf, South China Sea. Pulsed signal trains were detected with variations in the pulsed signal number (range of 6–76), mean inter-pulse interval (IPIs_m: 0.1–315 ms), and mean duration (D ranged from tens to thousands of milliseconds). Principal component analysis and hierarchical cluster analysis based on six acoustic parameters in the pulsed signal trains identified three categories of trains designated as clicks, burst-pulses, and buzzes. Buzzes and burst-pulses (different from those described in previous research) were detected for the first time in Indo-Pacific humpback dolphins in China. The results indicated that the IPIs_m was longest for clicks but shortest for buzzes, and the D values were longer for both clicks and burst-pulses than buzzes. The three train types could be identified based on the IPIs_m, with threshold values of 4.9 and 15.5 ms. The significant variations in the three vocalization types were related to surface behaviors, and buzzes could have a special function in foraging by this species, thereby requiring further research. These findings may facilitate future quantitative evaluations of the echolocation performance in wild Indo-Pacific humpback dolphins and provide important guidance regarding acoustic observations and the identification of this species.

Rechargeable Li‐O2 batteries (LOBs) are regarded as promising candidates for the next generation of energy storage devices. One of the major impediments is the poor cycle stability resulting from unreliable cathode catalysts and serious corrosion of Li anode, hindering the commercial application of LOBs. Herein, a synergetic strategy is proposed, including the design of a stable Co3Ru cathode catalyst via d‐band center modulation and the construction of a robust LiF/Sn/Li5Sn2‐PFDTMS hybrid protective layer on Li anode. Theoretical calculations reveal that the negative shift of the d‐band center provides a dominant descriptor for improving the catalysis activity and stability of Ru‐based catalysts. In situ construction of the PFDTMS‐enhanced LiF/Sn/Li5Sn2 hybrid layer possesses excellent mechanical stability and toughness, which can effectively shield the Li anode from corrosive reaction and ensure good Li+ transport. Consequently, the LOBs exhibit a long cycle life of 990 cycles (≈1980 h). This work confers the concept for high‐performance LOBs via rationally constructing stable catalysts and Li anodes. [ABSTRACT FROM AUTHOR]

22Ne(α,n)25Mg is one of the main neutron sources of the s process. 22Ne is produced by the 14N(α, γ)18F(β+)18O(α, γ)22Ne reaction chain in the helium burning, thus, the production rate of 22Ne is dominated by 14N(α,γ)18F and 18O(α,γ)22Ne. At the astrophysical relevant temperatures, the 18O(α,γ)22Ne reaction rates are determined by several low-energy resonances. In this work, the 18O(α,γ)22Ne reaction was measured at the 400 kV accelerator of Jinping Underground Nuclear Astrophysics experiment (JUNA). The γ-ray yields of the resonances between 470 to 770 keV were obtained.

Underground Nuclear Astrophysics Experiment in China (JUNA) has been commissioned by taking the advantage of the ultra-low background in Jinping underground lab. High current mA level 400 KV accelerator with an ECR source and BGO detectors were commissioned. JUNA studies directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. In the first quarter of 2021, JUNA performed the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O near the Gamow window. The experimental results reflect the potential of JUNA with higher statistics, precision and sensitivity of the data. The preliminary results of JUNA experiment and future plan are given.

The cosmic 1.809 MeV γ-ray emitted by the radioactive nucleus 26Al in the Galaxy is one of the key observation targets of the γ-ray astronomy. The 26Al is mainly produced by the 25Mg(p,γ)26Al reaction in the stellar Mg-Al reaction cycle. At the astrophysical relevant temperatures, the reaction rates of 25Mg(p,γ)26Al are dominated by several narrow resonances at low energy. This work reports a measurement of the low energy 25Mg(p,γ)26Al resonances at Jinping Underground Nuclear Astrophysics experimental facility (JUNA) in the China Jinping Underground Laboratory (CJPL).