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Coronavirus Disease 2019 (COVID-19), caused by the novel coronavirus, has spread rapidly across China. Consequently, there is an urgent need to sort and develop novel agents for the prevention and treatment of viral infections. A rapid structure-based virtual screening is used for the evaluation of current commercial drugs, with structures of human angiotensin converting enzyme II (ACE2), and viral main protease, spike, envelope, membrane and nucleocapsid proteins. Our results reveal that the reported drugs Arbidol, Chloroquine and Remdesivir may hinder the entry and release of virions through the bindings with ACE2, spike and envelope proteins. Due to the similar binding patterns, NHC (β-d-N4-hydroxycytidine) and Triazavirin are also in prospects for clinical use. Main protease (3CLpro) is likely to be a feasible target of drug design. The screening results to target 3CL-pro reveal that Mitoguazone, Metformin, Biguanide Hydrochloride, Gallic acid, Caffeic acid, Sulfaguanidine and Acetylcysteine seem be possible inhibitors and have potential application in the clinical therapy of COVID-19.

We present a design of an acoustic levitator consisting of three pairs of opposite transducer arrays. Three orthogonal standing waves create a large number of acoustic traps at which the particles are levitated in mid-air. By changing the phase difference of transducer arrays, three-dimensional manipulation of particles is successfully realized. Moreover, the relationship between the translation of particles and the phase difference is experimentally investigated, and the result is in agreement with the theoretical calculation. This design can expand the application of acoustic levitation in many fields, such as biomedicine, ultrasonic motor and new materials processing.

Damage points induced by 355 nm laser irradiation increase more quickly on the surface of fused silica in vacuum of about 10−3 Pa than in atmospheric air at the same fluence. The larger concentration of point defects in vacuum is confirmed by photoluminescence intensity. X-ray photoelectron spectroscopy and infrared absorption indicate the formation of sub-stoichiometric silica on the surface. The degradation mechanism of fused silica in vacuum is discussed.

Nonlinear dynamics of the sliding process of a chain driven with a constant velocity at one end in a periodic substrate potential is investigated. The driven chain exhibits distinctly different dynamical characteristics at different velocities. In the low velocity region, the chain moves in a stick–slip manner. When the driving velocity is increased, the stick–slip behaviour is replaced by complicated and regular oscillatory motions. The dependence of the dynamics on the coupling strength is studied and the step-like behaviour is found, where different steps correspond to different dynamical phases.

Long plasma channels induced by femtosecond laser pulses in air are diagnosed using the sonographic method. By detecting the sound signals along the channels, the length and the electron density of the channels are measured. Refocusing is also observed at different laser energies and different focal lengths. We find that the sonographic method has manifest advantages compared to other techniques.

A supercontinuum extending from 350 nm to more than 1700 nm is generated in microstructured fibre (MF) with randomly distributed air holes in cladding and core by using 15-fs pulses of a 790-nm laser. The maximum total power of the supercontinuum is 63 mW with 288 mW pump power from a 100× microscope objective. The wavelength and power of visible light ranging in the supercontinuum can be tuned by adjusting the input end of random the MF (to change pump incident point or incident angle). In particular, white light has been observed. The polarization states and waveguide modes of the visible light change with adjustment of the pump incident point or incident angle.

Spatial distribution of hot electrons with energies above 50 keV are investigated by an ethanol micro-droplet spray irradiated by linearly and elliptically polarized 150 fs laser pulses at an intensity of 1016W/cm2. Two symmetric hot electron jets with respect to the laser propagation direction are observed in the polarization plane for a linearly polarized laser field and in the plane of the long electric vector for an elliptically polarized laser field, respectively. Particle-in-cell simulations suggest that the resonance absorption on the spherical surface of the droplets is mainly responsible for the generation of the double-jet emission of hot electrons.

Photoinduced resistance change (ΔR/R) in an oxygen-deficient La0.9Sr0.1MnO3−δ thin film is studied. At room temperature, the resistance change of about 30% and response time of about 75 ns are observed under the illumination with a 532 nm laser pulse of 7 ns and light power of 750 mW. It is also found that ΔR/R changes with the light power. The phenomena are explained in terms of the photoinduced hole carriers and localized insulator-to-metal transition, which may have potential applications in optoelectronic devices.

The differential cross sections of 17F and 17O elastic scattering products on 208Pb have been measured at the Radioactive Ion Beam Line at Lanzhou (RIBLL). Two angular dispersion plots of ln (dσ/dθ) versus θ2 are obtained from the angular distribution of the elastic scattering differential cross sections. The angular dispersion plot exhibits a clear turning point for 17F in the range of small scattering angles 6°–20° due to its exotic structure, but for 17O, the turning point is not observed in the same angular range. The experimental results have been compared with previous data of other groups. Systematical analysis on the available data supports the above conclusion that there is an exotic behaviour of the angular dispersion plot of weakly bound nuclei with halo or skin structure as compared with that of the ordinary nuclei near stable line. Therefore the turning point of the angular dispersion plot appears at small angle for weakly bound nuclei with halo or skin structure, and can be used as a new probe to investigate the halo and skin phenomena of weakly bound nuclei.

Strong white light emission is observed from femtosecond laser propagation in air. The divergence angle of the white light emission is measured to be about 5 mrad. Young's double-slits and a Michelson interferometer are used to investigate the coherence. The wavelength components of the white light emission are identified to have a good spatial coherence and a coherence time of about 0.5 ps.

We theoretically investigate the electronic structure and spin polarization properties of Na-doped meridianal tris(8-hydroxyquinoline) aluminum (Alq3) by first principles calculations. It is found that the spin density is distributed mainly in the Alq3 part in the Alq3:Na complex. Electron charge transfer takes place from the Na atom to the Alq3 molecule, which induces asymmetric changing of the molecule bond lengths, thus the spin density distribution becomes asymmetric. Spin polarization of the complex originates from the preferable filling of the spin-split nitrogen and carbon p-orbitals because of the different bond length changes of the Alq3 molecule upon Na doping.

A spintronic near-field microwave imaging system without vector network analyzers is used to detect the distribution of microwaves, which are scattered by a sub-wavelength periodical metal wire grating. An ultra thin metal body with diameter of 100 μm (λ/300) is observed by imaging illuminated by a 10 GHz shining source. An application with high sensitivity and resolution detection is proposed in the microwave region under a weak applied external static magnetic field.

Magnetoresistance in the structure of ferromagnetic/nonmagnetic/ferromagnetic spin valves are studied theoretically from the spin diffusion theory and Ohm's law. The nonmagnetic layer could be an organic or inorganic semiconductor. Carrier mobility and the spin-flip time in organic semiconductors are different from those in inorganic semiconductors, and effects of these differences on the magnetoresistance in organic and inorganic spin valves are discussed. From the calculation, it is found that the magnetoresistance in inorganic spin valves is higher than that in organic spin valves. Effects of the conductivity matching and spin-dependent interfacial resistances between ferromagnetic and nonmagnetic layers, thickness of the nonmagnetic layer, and the bulk spin polarization of the ferromagnetic layer on the magnetoresistance are also discussed.

The effect of a vortical electric field on nonlinear patterns in excitable media is studied. When an appropriate vortex electric field is applied, the system exhibits pattern transition from chemical turbulence to spiral waves, which possess the same chirality as the vortex electric field. The underlying mechanism of this is discussed. We also show the meandering behavior of a spiral under the taming of a vortex electric field. The results obtained here may contribute to control strategies of patterns on surface reaction.

Dry laser cleaning (DLC) and laser shockwave cleaning (LSC) are used to remove the particulate contamination from SiO2 sol-gel optical films. The results show that the LSC with a shockwave initiated by plasma formation under a focused laser beam pulse offers much better efficiency than DLC. Silica particles up to 10μm on SiO2 films can be removed without substrate damage at a gap distance of 0.5 mm, and a more uniform surface microstructure can be obtained after LSC. Furthermore, it is demonstrated that the transmittance of contaminated SiO2 films can be restored to the as-deposited value after the LSC on dispersed-particle zones. LSC has potential applications in engineering-oriented large components.

Using the coherence theory of non-stationary fields and the characterization of stochastic electromagnetic pulsed beams, the analytical expression for the spectral degree of polarization of stochastic electromagnetic Gaussian Schell-model pulsed (GSMP) beams in turbulent atmosphere is derived and is used to study the polarization properties of stochastic electromagnetic GSMP beams propagating through turbulent atmosphere. The results of numerical calculation are given to illustrate the dependence of spectral degree of polarization on the pulse frequency, refraction index structure constant and spatial correlation length. It is shown that, compared with free-space case, in turbulent atmosphere propagation there are two positions at which the on-axis spectral degree of polarization P is equal to zero. The position change depends on the pulse frequency, refraction index structure constant and spatial correlation length.