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Since February 2012, CO2, H2O, and wind data at 10 Hz have been measured by the open‐path eddy covariance systems at 8, 16, 47, 80, 140, 200, and 280 m above ground level on the 325 m Beijing meteorological tower. Analysis of the data from 2013 to 2016 indicates that the annual averaged CO2concentration increased and the local and regional CO2emission decreased with the sequestration of background CO2concentration. The maximum values occurred during winter, and the minimum values occurred during summer. During spring, summer, and autumn, there was a constant CO2flux layer from 47 m to 140 m. However, during winter, CO2flux increased with height, and the maximum appeared at approximately 140 m and then decreased with height. Above 47 m, the CO2fluxes were represented as the net efflux, and below 16 m, the fluxes were near zero or a net uptake. At all observed heights, the diurnal variation in the CO2concentration displayed a clear cycle with a peak corresponding to the morning transportation rush hour. The local wavelet power spectra of the CO2concentration, CO2flux, and other meteorological elements identified significant cross‐wavelet powers near the 24 h and 365 day bands for the CO2concentration and flux with temperature, wind speed, friction velocity, and turbulent kinetic energy. Annual averaged CO2concentrations increased, while local one decreased with the sequestration of backgroundCO2concentration yearlyAbove 47 m, CO2flux was represented as net efflux; below 16 m, net uptake occurred because vegetation dominated in the fetch of the instrumentCO2concentration and flux varied in adiurnal cycle and had significant cross‐wavelet powers with other meteorological elements

The morphology evolution and coarsening behaviour of ?' (Ni3Al) phase in Ni–Al alloys were investigated by using the Cahn–Hilliard and Ginzberg–Laudan phase field equations, and the composition, order parameter and average particles size evolution coupling with the internal elastic strain were studied. Cubic ?' phase was presented firstly and then the rectangle particles were formed by means of coarsening; the mechanisms of ?' phase coarsening are Ostwald ripening or coalescence of neighbouring particles. The average particle size of ?' phase increases rapidly at the initial stage, and it slows down at the coarsening dominated stage. The average particle size follows a cubic law of ‘Lifshitz–Slyozov’ encounter modified theory in the coarsening regime.

The morphology evolution and coarsening behaviour of ˠ' (Ni3AI) phase in Ni-Al alloys were investigated by using the Cahn--Hilliard and Ginzberg-Laudan phase field equations, and the composition, order parameter and average particles size evolution coupling with the internal elastic strain were studied. Cubic ˠ' phase was presented firstly and then the rectangle particles were formed by means of coarsening; the mechanisms of ˠ' phase coarsening are Ostwald ripening or coalescence of neighbouring particles. The average particle size of ˠ' phase increases rapidly at the initial stage, and it slows down at the coarsening dominated stage. The average particle size follows a cubic law of 'Lifshitz-Slyozov' encounter modified theory in the coarsening regime. [ABSTRACT FROM AUTHOR]

Isothermal compression of hydrogenated Ti6Al4V alloy was carried out on a Gleeble-1500D simulation tester at the strain rate 3×10-3s-1and high temperatures. Before the isothermal compression, a simplified thermohydrogen processing (THP) was used for Ti6Al4V. Attention was paid to the effect of THP on subsequent compression behaviour. The results show that hydrogen can effectively lower the flow stress and deformation temperature and enhance the strain rate sensitivity index (mvalue) for isothermal compression. The increasing amount of ßphase and the ultrafine and equiaxial microstructure precipitated between the original aor ßlaths are the main reasons for the simplified THP to improve the formability of Ti6Al4V.

In this paper, a semisolid slurry of hypereutectic high chromium cast iron (HCCI) was prepared in a metal mould by a cooling slope body method under pressure. The results indicated that the size of the primary carbide in the semisolid hypereutectic HCCI specimens becomes much finer, and there is no shrinkage porosity in the semisolid microstructure under a pressure of 150 MPa. The impact toughness of a semisolid specimen without shrinkage porosity is increased by about 121 and 17% compared with those of conventional and semisolid specimens with shrinkage porosity respectively. Furthermore, using SiC particles of 80–100 mesh in size as abrasives, the wear resistance of semisolid specimens without shrinkage porosity is increased by about 78 and 20% compared with those of conventional and semisolid specimens with shrinkage porosity respectively.

Wavelengths and oscillator strengths for transitions among the levels of the terms belonging to the 3s2, 3s3p, 3s3d, 3s4s, 3s4p, 3s4d, 3p2, 3p3d, 3p4s, 3p4p, 3p4d, 3d4s, 3d4p, 3d4d and 3d2configurations of Mg-like Nd48+, Pm49+and Sm50+are systematically calculated using multiconfiguration-Dirac-Fock method. The predicted spectra of these three ions are, for the first time, extensively reported for n= 3-4 transitions in the 5-8 Å range and the variant trends of wavelengths and oscillator strengths along the isoelectronic sequence are discussed.

An improved multislice method is presented for performing dynamical calculations of high-energy electron diffraction and imaging in cases of inclined illumination. The method is shown by practical calculations to give results consistent with the traditional multislice method. The mathematical equivalency of the two methods for single-direction illumination cases is also given. However, there are some differences between the two methods for many-direction illumination cases such as in coherent convergent-beam electron diffraction (CBED). The improved multislice method may provide a more convenient expression for understanding coherent CBED problems and a more rapid algorithm for performing numerical calculations of the multislice approach in real space.

Rh/Cu superhydrophobic coatings with textured flower-like dual micro-nano structures were fabricated on copper substrates via electrodesposition of Rh followed by annealing treatment. The scanning electron microscopy and X-ray diffraction pattern were conducted to analyse the morphology and chemical composition of the coating surfaces, respectively. The water drops exhibited a water contact angle of 168+-1deg and a sliding angle of 0+-1deg on the coating surfaces which were obtained by etching in concentrated hydrochloric acid and nitric acid, electrodeposited at -1.0 V for 30 min and annealing in an oven at 180degC for 60 min. The prepared superhydrophobic coatings showed excellent water repellence and self-cleaning property due to its extremely high water contact angle.