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Objective: The aim was to evaluate the effect of oligo-chitosan modification on the properties of gelatin-based films. Methods: The gelatin-based films were prepared by using gelatin extracted from scrap pig skin as a cheap raw material and chitosan and polyvinyl alcohol as cross-linking agents. The structural and mechanical properties were characterized by Fourier infrared spectroscopy, X-ray power diffractometry, scanning electron microscopy, spectroscopy, and tensile test. Meanwhile, the ability of gelatin-based films in antioxidant, antibacterial, water stability and biodegradation were evaluated. Results: The multi-cross-linked gelatin-based films showed excellent mechanical properties, with a highest fracture stress of 37.09 MPa, a maximum tearing energy of 56.71 kJ/m², and a good physical form maintained after 48 h of immersion in water. In addition, the films possessed excellent light transmission (up to 92.32%), good oxidation resistance (radical scavenging capacity up to 75.12%), excellent antimicrobial and biodegradability (complete degradation time <45 h). Conclusions: The addition of oligo-chitosan has changed the properties of gelatin-based films in mechanics and biodegradation, and endowed the films with good antibacterial and antioxidant capacity, indicating that it had great potential application value in food packaging. [ABSTRACT FROM AUTHOR]

In this paper, a stochastic SIS epidemic infectious diseases model with double stochastic perturbations is proposed. First, the existence and uniqueness of the positive global solution of the model are proved. Second, the controlling conditions for the extinction and persistence of the disease are obtained. Besides, the effects of the intensity of volatility ξ 1 and the speed of reversion 1 on the dynamical behaviors of the model are discussed. Finally, some numerical examples are given to support the theoretical results. The results show that if the basic reproduction number ℛ 0 s < 1 , the disease will be extinct, that is to say that we can control the threshold ℛ 0 s to suppress the disease outbreak. [ABSTRACT FROM AUTHOR]

Vehicle electrification has been seriously considered as an industrial revolution to achieve sustainable transportation in China. With the development of the electric system, electric vehicles and railway systems are utilizing and generalizing. To accurately and adequately evaluate the energy consumption and CO2 emission effects of fuel and electric vehicles, this study focuses on these two kinds of vehicles, including buses and cars, and analyses their environmental impacts. Results show that electric vehicles consume less heat energy and release less CO2 emission than fuel vehicles do at the same distance. Public vehicles consume much less heat energy than private cars no matter which kind of fuel they use. In addition, the CO2 emission of fuel cars is larger than that of fuel buses. Moreover, electric energy is cheaper than gasoline and diesel. Therefore, the electric power will benefit the environment and society. The power should be recommended to substitute oil in the future. Although electric vehicles still have some limitations, such as prolonging the life of batteries, developing new energy, and green energy can guarantee energy security and benefit the environment and reduce the emission of CO2.

A series of Y-type chromophores L1–L3 containing bis(N,N-diethyl)aniline, bis(N-ethyl-N-phenylsilylethyl)aniline, and bis(3-phenylsilylpiperidin)aniline as electron donors, isophorone derivatives as a p-conjugated bridge, and phenyl-trifluoromethyl-tricyanofuran acceptors (CF3-TCF) as an acceptor were synthesized and investigated. However, the introduction of stronger acceptors does not guarantee the increase of electro-optical coefficients for all the chromophores. Chromophore L1 only achieved an r33 value of 110 pm V−1 due to its large absorption at 1310 nm. Poled films of 100 wt% chromophores L2–L3 showed high poling efficiencies and electro-optic coefficient due to large steric hindrance and hyperpolarizability of the chromophores. An ultrahigh r33 (351 pm V−1 and 277 pm V−1) and poling efficiency (3.50 + 0.10 nm2 V−2 and 2.63 ± 0.08 nm2 V−2) at 1310 nm were achieved for the film containing 100 wt% chromophores L2–L3. These results indicate that the rational match between the strength of the donor, acceptor, and p-conjugated bridge plays an important role in achieving a large electro-optic coefficient. [ABSTRACT FROM AUTHOR]