Two methods for constructing ZIF-8 nanomaterials with good bio compatibility and robust antibacterial applied to biomedical

Metal-organic framework materials not only possess porous structures, but also have excellent antibacterial properties. It is of great practical significance to prepare new antibacterial materials with excellent antibacterial effect by metal-organic framework materials. In our study, Zeolitic Imidazolate Framework-8 (ZIF-8) nanomaterials with antibacterial properties were prepared via the solvent method and diethanolamine template method. The materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cold field-emission scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption experiment, antibacterial experiment, and biocompatibility experiment. Results showed that ZIF-8 prepared by solvent method has a more typical hexagonal structure, larger specific surface area, and smaller pore size, and the values are 1812.07 m2g−1 and 2.2412 nm, respectively. At the same time, the materials prepared by the two methods have excellent antibacterial properties, and exhibit good biocompatibility at low concentrations, the antibacterial activity against Escherichia coli and Staphylococcus aureus are higher than 95%, and the cell viabilities of the selected five material concentrations of 12.5 µg mL−1, 25 µg mL−1, 50 µg mL−1, 100 µg mL−1 and 200 µg mL−1 are more than 70%. Therefore, this study provides a feasible method for preparing Nano-scale antibacterial functional particles, and it is of great significance to broaden the application field of ZIF-8 materials and prepare ZIF-8 drug-delivery functional materials.

Three-dimensional modeling of Ge₁₋xSix by the traveling solvent method to study the effect of gravity orientations under different rotational speed

This thesis presents a 3-D numerical simulation study for the growth of germanium-silicon (Ge₁₋xSix) under different gravity orientation and axial rotation. The process use for crystal growth of Ge₁₋xSix is traveling solvent method known as TSM. The TSM process has been tested on many alloys producing uniform and uncontaminated crystal products. In this model a mesh sensitivity analysis his been carried out to find an optimum mesh which provides accurate results while saving computational time. The full Navier-Stokes equations together with the energy, mass transport and continuity equations were solved numerically using the finite element technique. The application of gravity orientation and crucible rotation to the traveling solvent method is an attempt to control the buoyancy induced convection throughout the melt and to suppress the three-dimensional characteristics of unsteady heat flow. These different speeds of rotation were shown to have a considerable effect on the buoyancy induced flow. The solute distribution throughout the melt was also affected substantially. Taking these two factors into account plays a crucial role in the crystal growth process. The speed of rotation showed to have a significant effect on the intensity of the convective flow in the melt and an optimal rotational speed was encountered.

Three-dimensional modeling of Ge₁₋xSix by the traveling solvent method to study the effect of gravity orientations under different rotational speed

This thesis presents a 3-D numerical simulation study for the growth of germanium-silicon (Ge₁₋xSix) under different gravity orientation and axial rotation. The process use for crystal growth of Ge₁₋xSix is traveling solvent method known as TSM. The TSM process has been tested on many alloys producing uniform and uncontaminated crystal products. In this model a mesh sensitivity analysis his been carried out to find an optimum mesh which provides accurate results while saving computational time. The full Navier-Stokes equations together with the energy, mass transport and continuity equations were solved numerically using the finite element technique. The application of gravity orientation and crucible rotation to the traveling solvent method is an attempt to control the buoyancy induced convection throughout the melt and to suppress the three-dimensional characteristics of unsteady heat flow. These different speeds of rotation were shown to have a considerable effect on the buoyancy induced flow. The solute distribution throughout the melt was also affected substantially. Taking these two factors into account plays a crucial role in the crystal growth process. The speed of rotation showed to have a significant effect on the intensity of the convective flow in the melt and an optimal rotational speed was encountered.

Three-dimensional modeling of SiGe by the traveling solvent method in the presence of magnetic field and rotating crucible

Three-dimensional modeling of SiGe by the traveling solvent method in the presence of magnetic field and rotating crucible

Three Dimensional Effect of Axial Magnetic Field to Suppress Convection in the Solvent of Ge0.98Si0.02 Grown By the Traveling Solvent Method

A three dimensional numerical simulation of the effect of an axial magnetic field on the fluid flow, heat and mass transfer within the solvent of GE0.98Si0.02 grown by the travelling solvent method is presented. The full steady state Navier-Stokes equations, as well as the energy, continuity and the mass transport equations, were solved numerically using the finite element technique. It is found that a strong convective flow exists in the solvent, which is known to be undesirable to achieve a uniform crystal. An external axial magnetic field is applied to suppress this convection. By increasing the magnetic induction, it is observed that the intensity of the flow at the centre of the crucible reduces at a faster rate than near the wall. This phenomenon creates a stable and flat growth interface and the silicon distribution in the horizontal plane becomes relatively homocentric. The maximum velocity is found to obey a power law with respect to the Hartmann number Umax Ha⁻⁷/⁴

Three-dimensional modeling of SiGe by the traveling solvent method in the presence of magnetic field and rotating crucible

Three-dimensional modeling of SiGe by the traveling solvent method in the presence of magnetic field and rotating crucible

Three Dimensional Effect of Axial Magnetic Field to Suppress Convection in the Solvent of Ge0.98Si0.02 Grown By the Traveling Solvent Method

A three dimensional numerical simulation of the effect of an axial magnetic field on the fluid flow, heat and mass transfer within the solvent of GE0.98Si0.02 grown by the travelling solvent method is presented. The full steady state Navier-Stokes equations, as well as the energy, continuity and the mass transport equations, were solved numerically using the finite element technique. It is found that a strong convective flow exists in the solvent, which is known to be undesirable to achieve a uniform crystal. An external axial magnetic field is applied to suppress this convection. By increasing the magnetic induction, it is observed that the intensity of the flow at the centre of the crucible reduces at a faster rate than near the wall. This phenomenon creates a stable and flat growth interface and the silicon distribution in the horizontal plane becomes relatively homocentric. The maximum velocity is found to obey a power law with respect to the Hartmann number Umax Ha⁻⁷/⁴

Three-Dimensional Modeling of the Rotation Effect on the Growth of Ge₁₋ˣSiˣ, by the Traveling Solvent Method

The travelling solvent method known as TSM is a process used to produce pure and homogeneous crystals. The TSM process has been tested on many alloys producing uniform and uncontaminated crystal products. A three-dimensional numerical simulation for the growth of Ge1-xSix by the travelling solvent method under axial rotation has been modelled. In this model a mesh sensitivity analysis has been carried out to find an optimum mesh which provides accurate results while saving computational time, The full Navier-Stokes equations together with the energy, mass transport and continuity equations were solved numerically using the finite element technique. The application of crucible rotation to the travelling solvent method is an attempt to control the buoyancy induced convection throughout the melt and to suppress the three-dimensional characteristics of unsteady heat flow. The application of different rotational speeds on the solvent has also been investigated. These different speeds of rotation were shown to have a considerable effect on the buoyancy induced flow. The solute distribution throughout the melt was also affected substantially. Taking these two factors into account plays a crucial role in the crystal growth process. The speed of rotation was found to have a significant effect on the intensity of the convective flow in the melt and an optimal rotational speed was encountered.