Absolute dielectronic recombination rate coefficients of highly charged ions at the storage ring CSRm and CSRe

Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.

Energy Levels and Transition Rates for Laser Cooling Os-and a General Approach to Produce Cold Atoms and Molecules

High-resolution photoelectron energy spectra of osmium anions are obtained using the slow-electron velocitymap imaging method.The energy levels of excited states^(4)F_(7/2),^(4)F_(5/2)and^(4)F_(3/2)of Os-are determined to be 148.730(13),155.69(15),and 176.76(13)THz[or 4961.09(41),5193.4(49),and 5896.1(42)cm-1],respectively.The lifetime of the opposite-parity excited state^(6)D^(o)_(9/2)is determined to be 201(10)μs using a cold ion trap,about 15 times shorter than the previous result 3(1)ms.Our high-level multi-configuration Dirac–Hartree–Fock calculations yield a theoretical lifetime 527μs.Our work shows that the laser cooling rate of Os-is as fast as that of Th-.The advantages of Os-are its near-IR range cooling transition and simple electronic structure,which make Os-a promising candidate for laser cooling of negative ions.We propose a general approach to produce cold atoms and molecules based on the sympathetic cooling of negative ions in combination with a threshold photodetachment.

Temperature-Dependent Far-Infrared Absorption in Cyclotrimethylene Trinitramine Single Crystals Using Broadband Time-Domain Terahertz Spectroscopy

We investigate the absorption properties of cyclotrimethylene trinitramine(RDX) single crystals from ~15 to150 cm^(-1) using the terahertz time-domain spectroscopy. We observe that all the absorption modes exhibit strong anisotropic behavior in terms of the crystal orientations. We demonstrate that the anharmonic phonon model can well describe the temperature-dependent behaviors of these absorption modes. These results indicate that the intermolecular interaction plays a major role in the collective motion of large number of RDX molecules. Our findings provide important information for understanding and controlling the dynamic properties in the explosive materials.

Discovery of Triassic coal-bearing strata in the Daxing'anling Region, Northeast China

During the late Paleozoic to early Mesozoic,a tectonic transition occurred in Northeast China,marking a shift from the Paleo-Asian Ocean to the Mongolian Okhotsk and Paleo-Pacific tectonic domains[1].As a result of regional compression induced by oceanic closure and continental collision,stratigraphic records from this period are scarce,but such records are essential for elucidating the tectonic and paleographic evolution of the region during the transition.

Recombinant human erythropoietin ameliorates cognitive dysfunction of APP/PS1 mice by attenuating neuron apoptosis via HSP90β

Dear Editor,Recently,lower hemoglobin/anemia in the elderly is found to be associated with cognitive impairment and Alzheimer’s disease(AD),1 implying that erythropoietin(EPO)may be of benefit for AD.As a clinically safe-to-use drug,besides its hematopoietic function,recombinant human EPO(rhEPO)is reported to present multifaceted neuroprotective effects.2 Unfortunately,few clinical studies investigated the effect of rhEPO in AD patients.