vertebrae fastness is an important method to rehabilitate vertebrae structure and function,How to inplant the screw safely is a focus in clinic cure.The medical image and 3D model rebuilding is combined with reverse engineering,the vertebrae 3D model is constructed by CT image,the precise path to inplant the screw in vertebrae is obtained in 3D digital model,the method to create path for screw inplanting in vertebrae is researched.
This paper presents an investigation of the NACA 4412 trailing edge separation test case using the Lattice-Boltzmann code PowerFLOW. It is shown that the method, which does not predict the separation in two-dimensional simulations, delivers good results if a more realistic three-dimensional setup is used. The results compare favorably to experimental pressure distributions and velocity profiles in the boundary layer and in the wake. It is argued that this trailing edge separation is not a suitable test case to validate turbulence models in two-dimensional simulations.
The correlative introduction and analysis of a kind of industrial field pressure measurement sensor is carried out in this paper by us. The principle of work and power supply circuit of pressure sensor is studied in detail. The constant current source power supply mode is adopted in this paper, which is very good for certainty of measurement. In order to go a further step to explore sensitivity situation sensitivity performance, finite element analysis research method is taken for the pressure sensor chip for several times. By means of finite element analysis, we know that the pressure sensor has good sensitivity and degree of linearity. This paper provides several important scientific references for researching and designing the pressure sensor.
Biorefinery is pivotal to the sustainability of modern chemical industry. However, since biomass is oxygen-enriched, new and green chemical strategies are required for expanding the biomass derived chemical space. In this work, synthesis of natural products dihydrocapsaicin and dihydrocapsiate was achieved exclusively from lignocellulosic platform chemicals. Natural products dihydrocapsaicin and dihydrocapsiate were synthesized exclusively from lignocellulosic platform chemicals, using furfural (from hemicellulose) and methyl isopropyl ketone (from cellulose) through aldol condensation-hydrolysis-hydrodeoxygenation to synthesize 8-methylnonanoic acid and then combined with vanillin derivates (from lignin). This synthesis demonstrates the feasibility of constructing natural products entirely from renewable biomass platform through green processes. The utilization of inherent functional groups of biomass demonstrates their potential to open up chemical space.
Here, we report a unique porous FeCoAl Prussian blue analogue (PBA)-based core–shell catalyst (Na/Fe@FeCoAl-P) with a well-defined spatial arrangement of double-active interfaces for superior CO2 conversion to C2–C4 hydrocarbons. Compared to the traditional Na/Fe catalyst, which has a selectivity of 32.0% to C2–C4 hydrocarbons at a CO2 conversion of 38.1%, the resulting Na/Fe@FeCoAl-P0.1 catalyst exhibits significantly improved selectivity (40.8%) to C2–C4 hydrocarbons with a high olefin/paraffin (O/P) ratio of 8.7 at a largely improved CO2 conversion of 54% at 330 °C, while the CO selectivity decreases from 7.3 to 3.5%. Furthermore, the selectivity of C2–C4 hydrocarbons can reach 45.7% containing 38.7% of C2=–C4= products at 280 °C. In addition, the in-depth characterization results have indicated that the presence of FeCoAl PBA not only inhibits the generation of heavy hydrocarbons by the unique porous structure space but also considerably facilitates the formation of an abundant Fe5C2 phase for boosting Fischer–Tropsch synthesis (FTS) activity. Also, a distinctive reaction scheme of CO2 hydrogenation to hydrocarbons over the Na/Fe@FeCoAl-P0.1 catalyst is proposed on the basis of extensive characterizations. Moreover, we also demonstrate that porous-structured PBA is a highly promising material for use in CO2 hydrogenation, although its application has been rarely reported in CO2 Fischer–Tropsch synthesis.
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