Comparing simulated and experimental spectral line splitting in visible spectroscopy diagnostics in the HL-2A tokamak

We established the passive-visible spectroscopy diagnostics(P-VSD)and active-VSD(A-VSD)spectral splitting models for the HL-2A tokamak.Spectral splitting due to the influence of electromagnetic fields on the spectra in VSD is studied.Zeeman splitting induced by the magnetic field(B)is used to distinguish reflected light overlap in the divertor for P-VSD.Stark splitting caused by the Lorentz electric field(E_(Lorentz))from the neutral beam injection particle’s interaction with the magnetic field(V_(beam)×B)is used to measure the safety factor q profile for A-VSD.We give a comparison and error analysis by fitting the experimental spectra with the simulation results.The distinguishing of edge(scrape-off layer and divertor)hydrogen/deuterium spectral lines and the q profile derived from the spectra provides a reference for HL-2M VSD.

Regulating the growth of lithium dendrite by coating an ultra-thin layer of gold on separator for improving the fast-charging ability of graphite anode

With the ever-growing application of lithium-ion batteries(LIBs), their fast-charging technology has attracted great interests of scientists. However, growth of lithium dendrites during fast charge of the bat teries with high energy density may pose great threats to the operation and cause serious safety issues Herein, we prepared a functional separator with an ultra-thin(20 nm) layer of Au nanoparticles deposited by evaporation coating method which could regulate growth direction and morphology of the lithium dendrites, owing to nearly zero overpotential of lithium meal nucleation on lithiated Au. Once the Li den drites are about to form on the graphite anode during fast charging(or lithiation), they plate predomi nantly on the Au deposited separator rather than on the graphite. Such selective deposition does no compromise the electrochemical performance of batteries under normal cycling. More importantly, i enables the better cycling stability of batteries at fast charge condition. The Li/Graphite cells with Au nanoparticles coated separator could cycle stably with a high areal capacity retention of 90.5% over 95 cycles at the current density of 0.72 m A cm^(-2). The functional separator provides an effective strategy to adjust lithium plating position at fast charge to ensure high safety of batteries without a compromise on the energy density of LIBs.

Improvement of Plasma Performance Using Carbon Pellet Injection in Large Helical Device

A cylindrical carbon pellet with a size of 1.2L x 1.2φ mm to 1.8L x 1.8φ mm and a velocity of 100 m/s to 300 m/s was injected into large helical device （LHD） for an efficient fueling based on its deeper deposition instead of hydrogen gas puffing and ice pellet injection. Electron density increment of Ane = 10^14 cm^-3 is successfully obtained by single carbon pellet injection without plasma collapse. Typical density and temperature of the ablation plasma of the carbon pellet, e.g., 6.5× 10^16 cm^-3 and 2.5 eV for CII, are examined respectively by spectroscopic method. A confinement improvement up to 50% compared to ISS-95 stellarator scaling is clearly observed in a relatively low-density regime of ne = 2 × 10^13 cm^-3 to 4×10^13 cm^-3, and high ion temperature Ti（0） of about 6 keV is also observed with an internal transport barrier at ne = 1.2 × 10^13 cm^-3. In particular, the improvement in the ion temperature largely exceeds that observed in hydrogen gas-puffed discharges, which typically ranges below 3 keV.

Observation of Magnetic Dipole Forbidden Transitions in LHD and Its Application to Burning Plasma Diagnostics

Magnetic dipole forbidden （M1） transition was studied in large helical device （LHD） and F-, Si- and Ti-like M1 transitions are successfully observed for highly ionized Ar, Kr, Mo and Xe ions. The wavelengths measured in visible range for the heavy elements, which are carefully determined with extremely small uncertainties of 0.02 - 0.05 A as a standard wavelength of usual electric dipole （El） plasma emissions, are compared with theoretical predictions. The result shows a good agreement with recent Hatree-Fock calculation including semi-empirical adjustment. The M1 intensity for the F-like ions is examined by analyzing the intensity ratio of M1 to El. Density dependence of the ratio is experimentally verified by comparing with collisional- radiative model calculation on level population. The M1/E1 line ratio for the F-like ions is applied to the α （He^2＋） particle diagnostics in ITER, in which a steady-state operation of burning plasmas based on D-T fusion reaction is expected with α particle heating. Unfortunately, the present estimation suggests a negative result for the α particle measurement because the ratio is largely enhanced by the collisional excitation with bulk ions due to high ion temperature of ITER of 10 keV as assumed and the resultant effect of the collisional excitation with α particles becomes less. Meanwhile, the M1 transition, in particular, Ti-like WLIII （W^52＋） transition （3627 A） emitted in visible range, is very useful for diagnostics of the impurity behavior and the core plasma parameters in ITER.

Recovery and Genetic Characterization of a West Nile Virus Isolate from China

West Nile virus(WNV)is an important neurotropic flavivirus that is widely distributed globally.WNV strain XJ11129 was first isolated in Xinjiang,China,and its genetic and biological characteristics remain largely unknown.In this study,phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1 a and shares high genetic identity with the highly pathogenic strain NY99.Then,the full-length genomic c DNA of XJ11129 was amplified and assembled using a modified Gibson assembly(GA)method.The virus(named r XJ11129)was successfully rescued in days following this method.Compared with other wild-type WNV isolates,r XJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo.In summary,the genomic and virulence phenotypes of r XJ11129 were characterized in vivo and in vitro,and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.

Genetic differentiation and diversity of SARS-CoV-2 Omicron variant in its early outbreak

The recently emerged Omicron variant of severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2)has quickly spread around the world.Although many consensus mutations of the Omicron variant have been recognized,little is known about its genetic variation during its transmission in the population.Here,we comprehensively analyzed the genetic differentiation and diversity of the Omicron variant during its early outbreak.We found that Omicron achieved more structural variations,especially deletions,on the SARS‐CoV‐2 genome than the other four variants of concern(Alpha,Beta,Gamma,and Delta)in the same timescale.In addition,the Omicron variant acquired,except for 50 consensus mutations,seven great new non‐synonymous nucleotide substitutions during its spread.Three of them are on the S protein,including S_A701V,S_L1081V,and S_R346K,which belong to the receptor‐binding domain(RBD).The Omicron BA.1 branch could be divided into five divergent groups spreading across different countries and regions based on these seven novel mutations.Furthermore,we found that the Omicron variant possesses more mutations related to a faster transmission rate than the other SARS‐CoV‐2 variants by assessing the relationship between the genetic diversity and transmission rate.The findings indicated that more attention should be paid to the significant genetic differentiation and diversity of the Omicron variant for better disease prevention and control.