A tin oxide/diatomaceous earth (DE) composite was synthesized via the hydrothermal method without using a template or surfactant, and its humidity-sensing and controlling properties were investigated. The SnO2/DE composites have a special embedded structure, in which SnO2 nanoparticles are embedded in the DE porous frame. The optimal composites exhibit short response and recovery times (T = 3 and 8 s, respectively), and their response (S = 35.64) is 11.88 times higher than that of DE (S = 3). Furthermore, the optimal composite C-1:3 was tested to determine its humidity-controlling properties, which revealed that it possessed absorption (27 h, 12.04%) and desorption (5 h, 8.56%) characteristics. Regarding the selectivity, the C-1:3 sensor showed better sensing behavior to humidity than to NO2, NH3 and other gases. These beneficial properties of the composites are due to a honeycomb structure that endows the composite with a large specific surface area for adsorption of H2O molecules and allows charge transfer between the embedded SnO2 nanoparticles. The humidity-sensing mechanism is explained in detail by the Grotthuss proton transfer theory and density functional theory (DFT), which were used together with a Nyquist diagram to analyze the conditions of H2O adsorption. This study demonstrates a novel strategy for designing a material that can rapidly sense and control humidity and provides insights into the application of the composite in sensing and controlling environmental humidity at room temperature.

Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability.

A microencapsulated phase change material(PCM)was prepared by the in-situ polymerization method using low melting point paraffin and melamine-urea-formaldehyde prepolymer as core material and shell material respectively.Through optimization by orthogonal test, 94.15% paraffin was encapsulated and the microcapsule containing 61.78% paraffin was prepared successfully.Differential scanning calorimeter(DSC) was used to study the thermal properties of the microencapsulated PCM, and the results showed that the melt point and enthalpy were 12.53℃ and 137.16 J·g~ -1 , respectively.In addition,the hydrophilic-lipophilic properties of the microencapsulated phase change material was also investigated with the Washburn equation, and the result showed that the hydrophilicity of the PCM reduced with increasing content of paraffin in the PCM.

The maleic anhydride-styrene-vinyl acetate copolymer (MSV) was first prepared from maleic anhydride, styrene and vinyl acetate, then esterified by octadecanol and the maleic anhydride-styrene-vinyl acetate copolymer derivative (OMSV) was obtained. The OMSV was employed as pour point depressant (PPD) to improve the low-temperature fluidity of the 0# diesel fuel from Beijing Yanshan Petrochemical Company Limited. The result indicated that the solidification point (SP) and the cold filter plugging point (CFPP) were affected largely by OMSV, and when the mass fraction of OMSV in diesel fuel was 0.15%, the SP reduced by 31°C, the CFPP reduced by 11°C simultaneously.