Prediction of TBM penetration rate for different surrounding rocks and cutter head diameters.

The penetration rate (PR) of tunnel boring machines (TBMs) is often used to evaluate tunneling performance and predict construction period costs. However, most penetration rate (PR) prediction models are based on a single specific project, which leads to poor universality of the models.Furthermore, the value of the cutter head speed set for the prediction of the construction period in the survey and planning stages depends on manual experience and lacks theoretical guidance. Therefore, based on a set of engineering data from TBM of different surrounding rocks and diameters, this study statistically analyzed the distribution law of the cutter head speed (N) and the relationship between the field penetration index (FPI), geological parameters (uniaxial compressive strength (UCS) and the integrity coefficient of the rock mass (Kv)), and penetration (P). The results show that the FPI is strongly correlated with the geological parameters and the P. The geological and tunnelling parameters are the main factors affecting the penetration rate (PR). On the basis of this, prediction models of the FPI and P and a calculation model of the cutter head speed were developed, and a prediction model of the PR was obtained. The accuracy and reliability of this model were verified and analyzed for the EHe (EH) project. The average prediction error was 15.15 %.

TiO2 /SiO2 -NHOC-FA Nanocomposite as a Photosensitizer with Targeting Ability for Photocatalytic Killing MCF-7 Cells in Vitro and its Mechanism Exploration.

In the paper, a composite TiO2 /SiO2 -NHOC-FA was prepared using the coupling method which is a folic acid-targeted silica-coated titanium dioxide. Their structures were characterized by Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), transmission electron microscope (TEM) and zeta potential method. The results showed that the average diameter of the prepared TiO2 /SiO2 -NHOC-FA composite is 18 nm, which is spherical. Compared with unmodified TiO2 , TiO2 /SiO2 -NHOC-FA composite had superior water solubility and dispersion, and enhanced its photokilling activity by folic acid-targeted to FR (+) cells. In addition, photocatalytic TiO2 /SiO2 -NHOC-FA arrested cell cycle in G2/M phase of MCF-7 cells, resulting in a significant reduction of mitochondrial membrane potential (MMP), and also made the apoptosis rate, ROS components and intracellular calcium concentration increased. It killed the MCF-7 cells through apoptosis pathway. These results for the TiO2 /SiO2 -NHOC-FA composite can provide a theoretical basis for the photodynamic development of TiO2 .