Hong Chen

α-Zirconium phosphate (α-ZrP) nanocrystals were synthesized by refluxing method and subsequently exfoliated into extremely thin 2D nanosheets by tetrabutylammonium hydroxide (TBAOH) solution. Dynamic light scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the size distribution and morphology of α-ZrP nanosheets. Interfacial tension (IFT) and contact angle measurement were conducted by different concentrations of α-ZrP nanosheets solutions. The results displayed that the wettability of porous media surface was altered from oleophilic to hydrophilic and the IFT decreased with the increasing of α-ZrP nanosheets concentrations. A new method was proposed to calculate the Hamaker constant for 2D α-ZrP nanosheets. The calculated results displayed that α-ZrP nanosheets were not easy to agglomerate under experimental environment and when the interaction energy barrier increased, the transport amount of α-ZrP nanosheets also increased. Coreflooding tests were also performed with various concentrations and the oil recovery efficiency increased from 33.59 to 51.26% when α-ZrP nanosheets concentrations increased from 50 to 1,000 ppm.

Objectives: Compared with ordinary consumer goods, tobacco and tobacco products have their particularity, which not only plays an important role in the economic development of all countries in the world, but also plays a different role in people’s daily life. In China, the production and sales of tobacco leaves, cigarettes and other tobacco products as well as related tobacco machinery and raw and auxiliary materials have an important impact on fiscal revenue. As the Chinese stock market has basically completed the share-trading reform, stocks that were originally restricted from circulation have begun to circulate. With the continuous increase in the number of lifted bans, the phenomenon of major shareholders reducing their shareholding is also happening constantly. Methods: the paper provides empirical evidence to avoid the adverse effects of major shareholders’ reductions on the promotion of corporate value of listed tobacco Enterprises. From the perspective of the flow of shares after the major shareholders reduce their holdings, with the help of the theory of financing constraints, the article uses an empirical analysis method to explore the effect of the major shareholders of listed tobacco Enterprises on the value of the reduced listed private companies after they reduce their holdings. Results: the results show that when the equity of listed tobacco Enterprises is acquired by state-owned enterprises after the reduction of major shareholders, that is, when state-owned enterprises participate in the shares, the reduction of major shareholders contributes to the increase of the value of tobacco Enterprises. And the larger the reduction proportion of major shareholders, the greater the value of the enterprise. However, when major shareholders reduce their holdings and the equity is acquired by investment institutions and small and medium shareholders, it is not conducive to the improvement of corporate value. Especially when major shareholders maliciously reduce their holdings, it would have an adverse impact on the company’s development and stock price. Conclusion: therefore, from the perspective of enterprise value appreciation, no matter what the purpose is for major shareholders to reduce their holdings, the flow of equity to state-owned enterprises after the reduction is the best choice. The financing constraints of the enterprise could be reduced and it helps enhance the value of the enterprise.

In order to further develop efficient ultraviolet light-driven photocatalysts for environmental application, α-zirconium phosphate (α-ZrP) and carbon nitride (C₃N₄) were synthesized, respectively. Then, C₃N₄–ZrP compositing nanomaterials were prepared by compositing α-ZrP nanocrystals and C₃N₄ with different mass ratios. C₃N₄–ZrP compositing nanomaterials were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results illustrated that α-ZrP and C₃N₄ were successfully composited, and the polarization of the compositing nanomaterials was reduced compared with raw materials. The photocatalytic performances of C₃N₄–ZrP compositing nanomaterials with different mass ratios were studied by photodegradation of RhB under ultraviolet irradiation. All of the degradation rates of the C₃N₄–ZrP compositing nanomaterials system were achieved more than 90% after 18 min. When the mass ratio of C₃N₄–ZrP compositing nanomaterials is 2:1, the degradation efficiency achieved 99.95%, which is more efficient than other tested mass ratios. The result indicated the possibility of utilizing C₃N₄–ZrP compositing nanomaterials for environmental pollutants degradation.

Amphiphilic graphene oxide (A-GO) with grafted octylamine was prepared via a one-step method of N,N′-dicyclohexylcarbodiimide coupling and epoxide ring opening at a mild temperature of 40 °C. The phase of oil–water emulsion stabilized by the complexes of A-GO and the cetyltrimethyl ammonium bromide (CTAB) surfactant could invert three times by adding CTAB or A-GO. This process was called triple phase inversion, which was a function of the concentration of A-GO or CTAB surfactants. The conductivity and zeta potential measurements confirmed that CTAB could influence the carboxyl ionization of A-GO. In addition, the turbidity of the A-GO and CTAB mixed dispersion system revealed that the appearance and disappearance of precipitation occurred when CTAB or A-GO concentration was increased. Meanwhile, the emulsion prepared by mixing the dispersion with an equal volume of xylene at a fixed CTAB concentration also showed triple phase inversion as the A-GO concentration varied. Results indicated that the stability of the emulsion and the size of the emulsion droplets had a certain correlation during the phase inversion process, which varied with the concentration of CTAB or A-GO.

Highly crystalline α-zirconium phosphate (α-ZrP) nanoparticles were synthesized and exfoliated into nanosheets, and then the hydrophilic nanosheets were modified into hydrophobic nanosheets with octadecyltrichlorosilane (OTS). Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were applied to confirm the morphology and chemical structure of the nanosheets. Contact angle measurement was conducted to explore the wettability alteration of the hydrophobically modified α-ZrP nanosheets, and the result showed that the wettability of the core was changed into hydrophobicity. When ZrP–OTS nanosheets were injected during water-flooding, a Pickering emulsion will be formed. The droplet diameters and viscosities of the Pickering emulsions were measured. The hydrophobically modified α-ZrP nanosheets were applied in low-permeability sandstone cores and various concentrations were tested. The injectivity of the hydrophobically modified α-ZrP nanosheets was also studied and the result indicated that the nanosheets exhibit good injectivity. The mechanisms for enhancing oil recovery by utilizing hydrophobic α-ZrP nanosheets were analyzed: forming Pickering emulsions and increasing the viscosity of the displacing phase. Forming emulsions and increasing the viscosity of the flooding phase can enhance the microdisplacement efficiency, while good injectivity can also enhance the macrodisplacement efficiency. The result indicated the possibility of using hydrophobically modified α-ZrP nanosheets for enhancing oil recovery in a low-permeability reservoir.