Experimental research on the structural optimization of grouting holes in circular and rectangular pipe sections for trenchless pipe jacking.

In trenchless pipe jacking engineering practice, the formation of high-quality slurry jacket on the outer wall of pipe section is the key to effectively reducing the pipe-soil frictional resistance, improving the construction efficiency, reducing the construction risk and ensuring the construction safety. Herein, the multifunctional experimental apparatus for the pipe-soil frictional resistance testing is improved to ensure the smooth implementation of the subsequent experimental research. The influences of the structural parameters of grouting holes in circular and rectangular pipe sections on the pipe-soil frictional resistance and the states of slurry jackets around the various pipe sections are investigated respectively based on orthogonal experiment.

Efficient green InP-based QD-LED by controlling electron injection and leakage.

Green indium phosphide (InP)-based quantum dot light-emitting diodes (QD-LEDs) still suffer from low efficiency and short operational lifetime, posing a critical challenge to fully cadmium-free QD-LED displays and lighting. Unfortunately, the factors that underlie these limitations remain unclear and, therefore, no clear device-engineering guidelines are available. Here, by using electrically excited transient absorption spectroscopy, we find that the low efficiency of state-of-the-art green cadmium-free QD-LEDs (which ubiquitously adopt the InP-ZnSeS-ZnS core-shell-shell structure) originates from the ZnSeS interlayer because it imposes a high injection barrier that limits the electron concentration and trap saturation.

High efficiency blue light-emitting devices based on quantum dots with core-shell structure design and surface modification.

Blue quantum dot (QD) light emitting diode (QLED) developments are far lagging behind the red and green ones as it becomes difficult to balance charge injection and photo stability than the latter. Here, we introduced a combination of a low band energy shell with better surfactants, which largely meet both abovementioned requirements. Our simulation pinpoints that it is the exposed Se on the QD surface, which causes non-radiative relaxations.

Charge optimized many-body potential for aluminum.

An interatomic potential for Al is developed within the third generation of the charge optimized many-body (COMB3) formalism. The database used for the parameterization of the potential consists of experimental data and the results of first-principles and quantum chemical calculations. The potential exhibits reasonable agreement with cohesive energy, lattice parameters, elastic constants, bulk and shear modulus, surface energies, stacking fault energies, point defect formation energies, and the phase order of metallic Al from experiments and density functional theory.