Polyurethane, as a rubber material, can relieve the load on the ground and provide seismic design for the venue, which is of great significance for sports venues. In order to improve the seismic resistance and abrasion resistance of materials for sports fields and reduce accidents in sports, this article has carried out research on the polyurethane elastomer layered nanocomposites for sports fields and their preparation. Today's world is a challenging era of science and technology. The fields of biotechnology, information, medicine, energy, environment, and national defense and security are closely related to the development of high tech, and the requirements for materials are becoming increasingly diversified. Polymer nanocomposite coating has the dual characteristics of organic and inorganic components. It not only retains the advantages of a polymer but also endows it with versatility. It meets the current application needs. It is a hot spot in today's research. Among them, there are two major problems in the composite process of nanomaterials and polymers: dispersion and compatibility. How to improve the dispersion of nanoparticles and enhance the compatibility between nanoparticles and polymers is an urgent problem to be solved. In the method part, this article introduces a small amount of polyurethane and polyurethane elastomers formed after polyurethane modification and introduces layered compounds and nanocomposites and introduces several models involved in nanomaterials in terms of algorithms. In the analysis part, this paper conducts a comprehensive analysis of the hard segment mass fraction, mechanical properties, thermal decomposition behavior, degradation mechanism, and dynamic mechanical properties. With the increase of GO content, the tensile strength increases significantly and the elongation at break becomes smaller and smaller. When the GO content increases from 0% to 2%, the tensile properties of the WPU film increase from 2.6 MPa to 7.9 MPa and the fracture of the elongation decreased from 201.7% to 62.8%. This shows that the increase in GO content will make the composite material harder and brittle. It can be seen from the experimental results that the preparation of the polyurethane elastomer layered nanocomposite material designed in this paper has a good application effect on sports venues.
To evaluate the impact of health education with children popular oral science short drama on 10-year-old children's oral health knowledge, attitude, practice (KAP), and provide evidence for oral health education methods for children.A oral health education short drama for children was filmed. 10-year-old children from a primary school in Minhang district, Shanghai were selected as the study subjects. The groups were asked to watch the drama on campus at enrollment and the first month for health education. Self-made questionnaires were used to conduct corresponding oral health KAP surveys at the time of enrollment, the first month and the sixth month. The survey results were compared using SPSS 21.0 software package for t test and Chi-square test, to compare the changes in oral health KAP scores and the accuracy of each question before and after oral health education.One hundred and seventy-four children were followed-up. Before the intervention, the subjects' oral health knowledge, attitude, and behavior scores were (21.02±12.54), (74.48±19.87), (31.90±22.39), and (57.05±17.56), (85.06±14.97), (55.03±29.32) at the first month; and (71.76±16.27), (91.49±12.40), (73.99±27.46) at the 6th month, respectively. Compared with those before the intervention, significant increases were observed (P<0.001). Before the intervention, there was no significant difference in KAP scores between different genders, but there were significant differences in knowledge and behavior scores at 1 and 6 months after intervention between different genders(P<0.05).School oral health education through children oral science short drama has a good effect on improving the knowledge, attitude and behavior of oral health care for 10-year-old children, and it is more effective when repeat.
The microorganisms in permafrost could live in cold environment through the coadapted physicochemical process,which exists between microorganisms in permafrost and permafrost environment.In this paper,the relation between microbial number and soil physicochemical properties of permafrost at different depths at the headwaters of the urumqi River is analyzed by using fluorescence microscopy counting and oligo-culture techniques.Totally,20 samples from a 200-cm permafrost core were used as study materials.It is found that the number of cultivable bacteria has a significant positive correlation with soil water content,total carbon and total nitrogen concentrations,and a significant negative correlation with pH value.Meanwhile,the ratio of cultivable bacteria to total cell number decreases with depth.The results demonstrate that the number of cultivable bacteria in permafrost is closely correlated with soil physicochemical properties and depositional age.
As part of moving our optical pH and dissolved oxygen (DO) optical chemosensors toward industrial applications, we decided to explore a many-sensors-in-one principle. It was tested if physical segregation of the optical sensor components in a single sensor polymer could remove cross-talk and quenching. It was found that a design concept with an oxygen-responsive dye in polymer nanoparticles and a pH-responsive dye in an organically modified siloxane polymer resulted in a robust pH/O2 dual optical sensor. Individually, the O2-sensitive nanoparticles, a known component for optical DO sensing, and the pH sensor are operational. Thus, it was decided to test if nanoparticles enclosed within the pH-sensitive responsive sol-gel (i) could work together if segregated and (ii) could operate with a single intensity signal that is without a reference signal; developments within industrial optical sensor technology indicate that this should be feasible. The prototype optode produced in this work was shown to have a negligible drift over 60 h, bulk diffusion-limited DO response, and independent response to pH and O2. On the individual optode, pH calibration was found to show the expected sigmoidal shape and pKa, while the complexity of the calibration function for the DO signal was significant. While the engineering of the sensor device, optics, and hardware are not robust enough to attempt generic sensor calibration, it was decided to demonstrate the design concept in simple fermentation experiments. We conclude that the dual sensor design with the physical segregation of components is viable.
Polyimides are polymeric materials that are widely used in spacecraft applications owing to their unique properties. However, exposure to a low-Earth-orbit environment containing atomic oxygen (AO) results in the disintegration of polymeric materials on the surface of spacecraft, thereby affecting the lifespan. Along with the development of theoretical research, the reactive force-field (ReaxFF) interatomic potential has become a robust computational method for exploring, developing and optimizing the material properties. This study employs the ReaxFF reactive-force-field molecular dynamics simulation (ReaxFF MD) program to investigate and compare the performance of two typical polyimide materials, Kapton and Upilex-S, under the impact of AO. Various aspects such as variations in the temperature, mass loss, decomposition products, and damage propagation depth were examined. Although these materials have similar elemental composition (C/H/O/N), they have different structures. Our results indicate that AO is initially adsorbed on the surfaces of both Kapton and Upilex-S. The continuous impact of AO leads to chemical reactions between AO and Kapton/Upilex-S. Erosion proceeds from the surface toward the interior of the materials. Similar to the findings of Experiment 2 conducted by the Materials International Space Station, our results also reveal that Upilex-S exhibits a lower mass loss and erosion yield than Kapton under the same AO conditions. This difference is primarily attributed to the distinct molecular structures of both Kapton and Upilex-S. Our study could provide valuable technical support for the extensive application of Upilex-S in spacecraft.
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