Materials Science Forum Vol. 1032

Abstract: In this study, the effects of 555-777 defect on Young’s modulus, fracture strength and fracture strain of armchair graphene nanoribbons (AGNRs) and zigzag graphene nanoribbons (ZGNRs) were investigated by using Molecular Dynamics simulations under uniaxial tension. The simulation results show that 555-777 defect significantly reduces the fracture strength and fracture strain of AGNRs and ZGNRs, but has little effect on Young's modulus. The influence of 555-777 defect on the mechanical properties of AGNRs is greater than that of ZGNRs. This study provides a better understanding of mechanical properties of graphene nanoribbons.

Abstract: The selective adsorption of CH₄, H₂S, SO₂ and H₂O by alkali earth metal (AEM) decorated double vacancy graphene (DVG) was investigated with the first principles method. The most stable adsorption configurations, adsorption energy of CH₄, H₂S, SO₂ and H₂O on AEM_DVG have been discussed.

Abstract: In this paper, gold nanoparticles (AuPNs) and activated carbon (AC) modified electrode was used for the determination of luteolin. Porous activated carbon was made from coconut shell powder. The electrode was coated by Porous activated carbon, and then gold nanoparticles were electrodeposited on the porous carbon surface. Electrochemical behavior of luteolin was analyzed by gold nanoparticles@ activated carbon modified electrode. The results show that the detection range of luteolin is 1.8 μmol/L to 10 μmol/L (R² = 0.9863) with the detection limit of 0.1 nmol/L (3σ/slope), and the recommended method has a good recovery for the detection of luteolin in real urine.

Abstract: In this paper, a composite micromachining process is introduced. By adjusting the surface microstructure, a composite coating with two kinds of materials with different characteristics was fabricated. Carbon steel is used as the substrate material, and laser processing is used to obtain the micro morphology on the substrate surface. nanoSiC particles were selected as one of the coating materials, and the SiC coating was added through the process of micropore induced nanoparticles self-assembly. Ni was selected as another coating material and added by electrodeposition. This processing method can be used to prepare multifunctional surface coating, combining the characteristics of different materials. This work can provide an idea to create more excellent multifunctional surfaces.

Abstract: YGdO₃:Er³⁺ nanoparticles were successfully synthesized by pulsed laser ablation in liquid method. The structural and morphological properties of the product are investigated by X-Ray diffraction and transmission electron microscopy. The upconversion photoluminescence properties were investigated in detail. Obvious stark splitting phenomena were observed in the green and red emission bands. The decay behaviors of three emission bands were studied. Based on thermal coupled energy level related upconversion fluorescence intensity ratio, the temperature sensing properties of product were studied. Linear function has beenused to reveal the relationship between fluorescence intensity ratio and temperature. Using stark sublevels related emission bands, sensitivity of the temperature sensor was successfully enhanced. These results suggest the YGdO₃:Er³⁺ nanoparticles prepared via pulsed laser ablation in liquid are promising luminescent materials for optical thermometry.

Abstract: In this paper, a thermal inkjet printing simulation model is established in the CFD simulation platform, and the influence of inkjet driver parameters and ink physical parameters on the printing process is studied by numerical simulation. The evaporation-condensation model is coupled with the VOF multiphase flow model in Fluent software to establish a thermal inkjet printing process simulation model. Based on the orthogonal test method, we investigate the influence of fluid physical parameters (ink viscosity, surface tension) and inkjet driver parameters (heater temperature value) on droplet formation by changing the physical parameters of the material and the boundary conditions of the model. Through the comparison of the results, exploring the adjustment rules of thermal inkjet technology and obtaining the optimal combination of material and process parameters for high-quality ink drop formation.

Abstract: The spin Hamiltonian parameters (SHPs, g factors and hyperfine structure constants) defect structure for LiMgPO₄ doped with 0.1% Co²⁺ at 4.2 K are theoretically investigated from the perturbation formulas of the SHPs for a rhombically distorted octahedral 3d⁷ cluster. The impurity Co²⁺ on host Mg²⁺ site is found to suffer the larger axial relative compression ratio ρ (≈ 0.76%) and the planar angular variation Δφ (≈ 6.64^°) related to the host oxygen octahedron due to size mismatch. The calculated SHPs based on the above defect structure show good agreement with the measured results. Present study can be helpful to the preparation and characterization for the local structures for transition-metal impurities in lithium-magnesium phosphate, which may is helpful to search for the phosphor materials with better dosimetric characteristics.

Abstract: The combination of additive manufacturing technology and cartilage tissue scaffold construction provides a new way for clinical treatment of cartilage injury. The high priority of the cartilage scaffold is closely related to the excellent biomechanical properties, fatigue life and medical performance. In this paper, three kinds of cartilage scaffolds are designed, and three-dimensional parametric geometric and numerical simulation models are established. Based on the simulation analysis and comparison of the three kinds of scaffolds, a scaffold model is finally determined. The porosity reaches 87.38%, the equivalent elastic modulus is 9.64Gpa, and it has permanent fatigue life in service environment. It concluded that the designed Ti6Al4V titanium alloy scaffold is suitable for cartilage transplantation.

Abstract: In order to study the effect of temperature-confining pressure coupling on the creep behavior of rock-like specimen with precast internal fissures, the creep tests under different temperatures and confining pressures are carried out. The test results show that the rock presents primary creep stage and steady creep stage at low stress levels. Under the condition of high stress, the creep process of rock shows an obvious accelerated creep stage. The curve of accelerated creep stage of rock gradually smoothing with the increase of confining pressure, and the corresponding creep failure time gradually increases. The failure under low confining pressure is mainly tensile failure. The high confining pressure is the shear failure, or even the mixture of shear and plastic failure.

Abstract: ZTC4 alloy prepared by electron beam melting was hot isostatically pressed, the macro-and microstructure were characterized by stereo microscopy and optical microscopy, the tensile properties were tested and the fracture profiles were characterized using scanning electron microscopy. The results show that: The vertical deposition samples exhibit coarsen epitaxial columnar grains and the parallel samples show equiaxed grains, and microstructure are basket-weave α+β phase. The vertical deposition samples exhibit very high ultimate tensile strength and yield strength but poor ductility with elongation and shrinkage, and show generally more planar and faceted fracture morphology. The anisotropy in tensile properties is mainly due to the difference in the orientation of the columnar grains with respect to the tensile test direction, and the characteristics of the minor fracture plane are mainly related to the α colonies.