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Recently, the composite materials developed by the combination of polymer and inorganic nanomaterial have gained various attraction for researchers. In this paper, the negative charged silica nanoparticles (silica NPs) with hydroxyl groups on the surface were mixed with the amphiphilic polymer having positive charged hydrophobic groups to form a NP-polymer composite at the high temperature and high salinity condition. The thickening mechanism of silica NPs on amphiphilic polymers in high salinity condition was analyzed by measuring the viscosity and viscoelasticity of solution compared with HPAM. In order to clarify the function of the spatial network structure, the β-cyclodextrin (β-CD) was used to destroy the associated structure, and the microstructure was analyzed by scanning electron microscopy (SEM). Results revealed that the apparent viscosity and viscoelasticity of the polymer solution significantly increased only by involved silica NPs, and a viscous system also turned into an elastic one increasing. This study concludes that silica NPs collaborate with the hydrophobic association structure formed by the amphiphilic polymer due to electrical interaction and hydrogen bond. Thus, silica NPs can strengthen the spatial network structure. This kind of composite material provides a new way to increase the viscosity of the polymer at elevated temperature, and enhances its application in high salinity reservoirs.

Anaerobic granular sludge (AGS) is a promising technology for organic wastewater treatment and energy recovery. In this study, three different kinds of Fe and Fe oxides nanoparticles (Fe

A quantitative stability evaluation method of a profile control system based on fluorescence intensity of fluorescent polymer microsphere was constructed due to the inaccurate measurement of conventional method. One kind of fluorescent polymer microspheres were prepared in this research, and microstructure of them was characterized by FT-IR spectra, laser particle size analyzer, inverse fluorescence microscope and ESEM. The swelling behavior of polymer microspheres was evaluated by weighing method. The fluorescent intensity of polymer microspheres was measured by fluorescence spectrometer. The stability influence factors and the stability mechanism of florescent polymer microsphere profile control system(FPMPCS)were studied using Fluorescent Stability Index (FSI) which was proposed in this research. The results show that higher polymer or surfactant concentration can promote the stability of the system. There is great influence of temperature on the system stability during the high temperature range, and every kind of polymer microsphere has an optimum salinity from the aspect of stability. There is a limit to improve the system stability by reducing the average size of fluorescent polymer microspheres. To improve the stability of this kind of system, bulk viscosity, the space barrier and electrostatic repulsion among the particles should be considered.

Chemical demulsifiers were widely applied for demulsification of crude oil emulsions which were generally formed with natural stabilizers during the extraction. Based on our previous study of the light crude oil emulsions stability, the demulsification performance of four classes of nonionic poly(ethylene oxide) poly(propylene oxide) copolymer demulsifiers and sodium dodecyl sulfate (SDS) as well as their dynamic demulsification process on the W/O light crude oil emulsion were analyzed by the multiple light scattering method. The demulsification mechanism of these demulsifiers were illuminated by the measurement of dynamic interfacial tension (IFT), dynamic interfacial viscoelasticity, rupture rate and microscopic changes of oil film by single droplet method. The results have shown that demulsification performance doesn’t depend on IFT, though effective demulsifiers could have a lower IFT around 1 mN/m. Multiple light scattering data and dynamic IFT clarified the demulsification process of efficient demulsifiers, quick diffusion and adsorption of demulsifiers, palpable change in interfacial property, droplet coalescence and sedimentation. The capacities of demulsifiers to penetrate into the interface and to decrease the interfacial viscoelasticity were the dominating demulsification mechanisms. The quantitative interpretation of multiple light scattering data associated with the dynamic IFT and interfacial viscoelasticity illuminated the demulsification mechanism of different demulsifiers. The rupture rate and dynamic rupture process of the oil film between the aqueous phases also vividly showed the differences in demulsification process. The nonionic demulsifiers AR902 and PR929 with aromatic groups has the highest speed and best performance due to the similar aromatic groups with those in asphaltenes, which produced the least stable oil film. This study provides a valuable guideline for the selection of demulsifier for light crude oil emulsions and enhanced demulsification mechanism studies.

The low-temperature liquid nitriding of stainless steels can result in the formation of a surface zone of so-called expanded austenite (S-phase) by the dissolution of large amounts of nitrogen in the solid solution and formation of a precipitate-free layer supersaturated with high hardness. Erosion–corrosion measurements were performed on low-temperature nitrided and non-nitrided 316L stainless steels. The total erosion–corrosion, erosion-only, and corrosion-only wastages were measured directly. As expected, it was shown that low-temperature nitriding dramatically reduces the degree of erosion–corrosion in stainless steels, caused by the impingement of particles in a corrosive medium. The nitrided 316L stainless steels exhibited an improvement of almost 84% in the erosion–corrosion resistance compared to their non-nitrided counterparts. The erosion-only rates and synergistic levels showed a general decline after low-temperature nitriding. Low-temperature liquid nitriding can not only reduce the weight loss due to erosion but also significantly reduce the weight loss rate of interactions, so that the total loss of material decreased evidently. Therefore, 316L stainless steels displayed excellent erosion–corrosion behaviors as a consequence of their highly favorable corrosion resistances and superior wear properties.

Addition of ferric oxides into flocculent anaerobic sludge was reported to enhance methanogenesis due to accelerated direct interspecies electron transfer (DIET) between syntrophic microbial communities. However, it is generally hard to incorporate Fe oxides into already matured anaerobic granular sludge (AGS) due to its special aggregated structure. In this study, a novel method was attempted to fast incorporate Fe oxides into AGS through in-situ microbial formation and immobilization of biogenic Fe oxides. Factors influencing the formation of Fe oxides were investigated and effects of Fe oxides on the acidogenic and methanogenic performance of AGS were assessed. Results showed that AGS could form Fe oxides mainly in the form of magnetite and hematite through biological reduction of Fe(III) oxyhydroxide. A maximum loading amount of 83.9 mg Fe/g MLVSS was obtained at pH 7 after contacting with 60 mM Fe(III) oxyhydroxide. The efficiency of electron donors which supported Fe(III) reduction followed the order of pyruvate > propionate > glucose > acetate > lactate > formate. Addition of electron transfer mediators (ETMs) promoted the formation of Fe oxides and their performance followed the order of AQDS > AQC > humics > FMN > riboflavin. Presence of Fe oxides in AGS (134.6 Fe/g VSS) increased the production of volatile fatty acids (VFAs) and methane by 16.28% and 41.94% respectively, comparing to the control. The enhancement may be attributed to increased conductivity and stimulated growth of exoelectrogens (Clostridium and Anaerolinea) and methanogenic endoelectrogens Methanosaeta in granular sludge which may strengthen direct interspecies electron transfer between syntrophic microbial communities. Overall, this study provides an alternative strategy to improve the digestion performance of AGS through in-situ formation and immobilization of biogenic Fe oxides.

As an important part of terrestrial ecosystem and the most sensitive to environmental changes, mountainous areas are rich in biodiversity and high value of ecosystem productivity. However, due to the unsustainable exploitation of natural resources, most of the world’s mountain ecosystems are being subjected to soil erosion and biodiversity is rapidly being lost, so the establishment of mountain ecological reserves is of great importance. In view of this, this paper used the Qinling-Daba Mountain, Qinling Mountain and Daba Mountain of China as the research area. On the basis of various simulated ecosystem service from 2000 to 2015, the root mean square deviation analysis and ordered weighted averaged model were used to determine the spatial changes of ecosystem service on environmental gradients, the tradeoff between ecosystem services and the selection of optimal protection areas. Our results proved that ① net primary production, soil conservation and habitat quality were increase significantly with increasing altitude and vegetation cover fraction gradient, but were weaken water yield and grain production. ② The change in the trade-off between multiple pairs of ecosystem services in the Daba Mountain was stronger than in the Qinling-Daba Mountain and the Qinling Mountain, especially the trade-off relationship related to water yield. ③ Considering various scenarios and conservation efficiency, it was found that scenario 7 was the best solution. The net primary production, soil conservation, habitat quality, grain production, and water yield protection efficiency were 1.261, 4.845, 1.059, 1.333, and 1.390 respectively. Priority conservation areas were mainly distributed in mid-altitude, high-vegetation, and high-mean annual precipitation areas. In this study, the combination of ecosystem services and priority conservation areas can play an important role in the management of the Qinling-Daba Mountain, and provides a meaningful reference for the selection of nature reserves.

Low elastic polymer microsphere (L-EPM) had been a promising conformance control agent with the wide application of polymer microspheres. The filtration loss characteristics, core damage and selective conformance control performance of L-EPM conformance control system were studied. The results showed that L-EPM system had less damage to the matrix core and the influence of filtration loss on conformance control treatment could be neglected in indoor experiments. When the high permeability layer was fixed, the larger the permeability ratio, the better the profile improve ability. For the cores with same permeability, water plugging rate of L-EPM system was much higher than that of oil plugging rate. For heterogeneous reservoirs with interlayer channeling, the plugging position of L-EPM determined the conformance control performance and the following oil recovery. L-EPM with good deformation and shear resistance had good adaptability to the conformance control treatment in heterogeneous reservoirs with interlayer channeling.

Emulsions stabilized by the supramolecular systems with sodium polyacrylic acid and amphiphilic polymers with different hydrophobic monomer contents were investigated. Multiple-light scattering was used to characterize the stability of emulsions. Optical microscopy and particle size analyzer were utilized to determine the droplet size distributions. The glass-etching micro model and microscopy were used to observe the emulsion stability in the porous media. To explore the stability mechanisms of emulsions, the rheology of the external phase and the oil/water interface were determined with the Physica MCR301 Rheometer. Emulsions formed by the supramolecular systems exhibit a better stability than the individual amphiphilic polymer systems. Moreover, the stability of emulsions formed by the supramolecular systems increases with the hydrophobic monomer content of amphiphilic polymers. The results can be attributed to the large viscous effect of the external phase and the high strength of the oil/water interfacial film in the emulsions. The results provide a theoretical foundation for future studies of the oil displacement efficiency by amphiphilic polymer supramolecular systems in tertiary oil recovery.

Scale formation of oil and gas production is a serious problem as major causes of formation damage affecting recovery efficiency. Investigation the permeability reduction caused by scale formation of sandstone cores by mixing formation water and injection water with different ratio under various temperatures and differential pressure is conducted in this study. X-ray diffraction (XRD) technique is used to investigate to judge the types of inorganic scale by analyzing its crystalline composition. Scale prediction and beaker test results show that the inorganic scale produced by poor compatibility of formation water and injection water in XX oilfield is calcium carbonate. With the increase in the ratio of injection water to formation water, the scale of calcium carbonate scale first increases and then decreases. The scale of calcium carbonate is gradually increasing with the decrease of pressure and increase of temperature. The dynamic scale location monitoring method is proposed to predict the degree of oilfield blockage based on the pressure difference between multi-pressure measuring points of the core. Dynamic scale location monitor tests show that inorganic scale blockage occurs in the position range of 0–1/10 around injection well in the early stage of water flooding, and further increase of injection rate will result in migration leading the blockage occurs in the position range of 1/10–6/10 near the injection wells. The prediction results are consistent with the actual blockage in the oilfield, proving that this method guides significance of predicting blockage in water flooding. This method can be used in both onshore and offshore oilfields using water flooding as a secondary oil recovery.

Polyacrylamide microspheres have been successfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir produced fluid, fluorescent polyacrylamide microspheres P(AM-BA-AMCO), which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribution in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, Na2CO3, and dispersant. The bonding characteristics of microspheres were determined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultraviolet irradiation in the produced fluid, even though they had experienced extrusion and deformation in the sand pack.

The betaine-type amphiphilic polymer exhibits excellent salt-thickening properties due to the presence of betaine groups, but it also has some defects, such as poor water solubility at high betaine groups content, the viscosity-thickening ability is poor under the low betaine groups content. In order to solve the problem of poor viscosity-increasing ability of betaine-type amphiphilic polymers at low betaine group content, a cyclodextrin polymer was synthesized through free radical copolymerization. Characterization of the synthesized product was conducted by means of FT-IR and 1H_NMR. The two polymers were subjected to host-guest inclusion. Changes of viscosity, viscoelasticity, shear resistance and micro-morphology of the host-guest inclusion complex were measured by viscometer, rheometer, scanning electron microscope, and atomic force microscopy. The results showed that the optimal inclusion ratio for the complex was cyclodextrin polymer to betaine-type amphiphilic polymer ratio of 1:1. When the concentration of the host-guest inclusion complex reached 3000 mg/L, its viscosity increased twice compared to the betaine-type amphiphilic polymer with the same concentration. The host-guest inclusion complex was also more shear-resistant, which poses great potential application in chemical enhanced oil recovery.

Hydrophobically modified polyacrylamide (HMPAM) is widely used in petroleum development, whereas it still confronts challenges in high salinity reservoirs. In this work, a twin-tailed modified polyacrylamide was introduced and characterized by FT-IR, 1H NMR and TGA. The rheological properties and thickening mechanism were investigated by viscosimetry, rheology, macroscopic appearance, dynamic light scattering, fluorescence spectroscopy and β-cyclodextrin inclusion. The results revealed that by increasing NaCl from 0 to 50 g/L, the critical association concentration declined and solutions transformed from a transparent fluid of 115 mPa·s to viscoelastic fluid of 2040 mPa·s. Eventually, the viscosity decreased with white precipitation at 200 g/L NaCl. The salinity conduced to the aggregate of hydrophobic groups, while excessive aggregate decreased the hydrodynamic volume, which in turn caused a reduction of macroscopic viscosity. Higher polymer concentrations were conducive to better salt-thickening property. This copolymer showed great salt resistance and prospects for application in high salinity reservoirs.

Dynamic covalent bonds are widely used to construct nanosystems or self-healing materials with stimulus response. Here we developed a responsive wormlike micelles system based on pH-directed hydrophilic of hydrotrope, which was formed by mixing the cetyltrimethylammonium bromide (CTAB), 4-formylbenzoic acid (FA) and hexylamine (HA) at the molar ratio of 60:25:25 (CTAB/FA/HA). The rheological measurement, appearance observation, Cryo-TEM and 1H NMR were used to explore the characteristics of solution. With the pH increase from 6.01 to 12.07, the CTAB/FA/HA solution underwent transitions from a water-like fluid to viscoelastic fluid and finally converted to a gel-like solution, and the viscosity continuously increased from ~1.1 mPa·s to ~68,000 mPa·s. The drastic variation in rheological behaviour was attributed to the pH dependent combination of FA− and HA, which reduced the hydrophilicity of FA− and made hydrotrope transfer from the aqueous phase to the interior of the micelle. In contrast, the CTAB/p-phthalic acid/HA solution cannot achieve transition of hydrotrope due to the consistent hydrophilicity of disodium phthalate (p-DPA2−) and the viscoelasticity without any change by increasing pH. Besides, the viscoelasticity of CTAB/FA/HA solutions can be reversed over 3 cycles by adjusting the pH.

The amphiphilic polymer supramolecular system with high viscosity was constructed by electrostatic interaction between the cationic amphiphilic polymer and polyorganic acid, which expanded the thickening mode of amphiphilic polymer system. The optimum conditions for the construction of amphiphilic polymer supramolecular system and its thickening ability under reservoir conditions such as salinity, temperature and shear rate were explored by means of viscosity measurement. The intrinsic relationship between the macro-rheological properties of supramolecular system and the micro-morphology of solutions was also investigated by means of dynamic rheology, dynamic light scattering and SEM analysis. The results showed that the supramolecular system of cationic amphiphilic polymer PACD with 0.75 M ratio of polyacid could achieve ideal thickening effect at pH = 9. Moreover, the supramolecular system still maintained considerable viscosity at high temperature and high salinity. Amphiphilic polymer supramolecular systems had more compact microstructures and larger hydrodynamic volumes, which provided excellent thickening properties.

A novel pH-responsive wormlike micelle was formed by combining one kind of anionic surfactant (sodium dodecyl trioxyethylene sulphate (SDES)) with inorganic salt (sodium phosphate (Na3PO4)). The morphology transition of the system was represented by rheology, macroscopic appearance, dynamic light scattering and cryo-TEM images. Besides, conductivity and surface tension measurement were also used additionally to illustrate the transition mechanism. The results proved that the morphology transition of this system can be realized by the sodium ion release of phosphate adjusted by pH, and the aggregates transformed from spherical micelles to wormlike micelles with high viscosity by adding HCl. In addition, the viscosity increased slowly by further addition of inorganic base. The utilization of the ion release of inorganic salt expands the new ideas of pH-responsive wormlike micelle construction.

Inoculated with compost from methane oxidation habitats, the differences of methane oxidation capacity were compared and investigated after suspended-growth process and attached-growth process. The result showed that the ceramsite-compost matrix was formed in short time (3d) under the suspended growth condition and its methane oxidation capacity increased remarkably. The peak methane oxidation rate was 52.7 g CH 4 ·m -3 ·h -1 after suspended-growth process. However, the methane oxidation capacity of ceramsite was lower after attached-growth process with the peak methane oxidation rate of 13.5g CH 4 ·m -3 ·h -1 .

Angiogenesis is of great importance in bone tissue engineering, and has gained large attention in the recent 10 years. However, little research has been done on the effect of biodegradable materials, especially their degradation products on the angiogenesis process. Strontium-doped calcium polyphosphate (SCPP) has been proved to be able to promote osteoblasts growth in vitro before. In the present work, the interaction of endothelial cells (ECs) with the scaffold of SCPP was investigated to evaluate its potential influences on angiogenesis. The cell adhesion on SCPP scaffold as well as the angiogenic behaviors including proliferation, migration and tube-like structure (TLS) formation of ECs treated by its degradation products was tested. The results were compared with those of CPP group and physiological saline (negative control). As the results showed, the surface of SCPP could promote the adhesion and spreading of ECs. Ca 2+ and Pi as well as Sr 2+ were the main degradation products of SCPP. They did not inhibit but could promote the proliferation of ECs within 90 days. Moreover, they could induce the migration and TLS formation of ECs. Since SCPP bears the ability to improve the adhesion and angiogenic behaviors of endothelial cells, it might benefit angiogenesis and serve as a more promising scaffold for bone tissue engineering application. Besides, this work may provide a new method for in vitro evaluation of biodegradable materials’ potential effects on angiogenesis.

Nanosized silver particles were uniformly distributed on the surface of silicon particles by electroless deposition (ED) and high-energy mechanical milling (HEMM) methods, respectively. The HEMM-prepared Si/Ag composite with 10 wt.% silver exhibited a high first coulombic efficiency of 83.4% and a large capacity of ca. 800 mA h g − 1 over 30 cycles as a result of conductivity enhancement. It was suggested that electric contact between silicon particles played a significant role in improving the cyclability of silicon electrode.

Lithium nickel manganese oxide of LiNi 2 / 3 Mn 1 / 3 O 2 with α-NaFeO 2 type layered structure was prepared by a new process with layered double hydroxide NiMn-LDHs and LiOH·H 2 O as precursors in the temperature ranging from 450 to 950 °C. Among all the products, LiNi 2 / 3 Mn 1 / 3 O 2 prepared at 750 °C delivered an initial discharge capacity of 187 mAh/g in the potential region of 2.5–4.5 V vs. lithium, and remained as high as 160 mAh/g in the 10th cycle.

A new layered type lithium nickel manganese cobalt oxide with the composition of LiCo{sub 1/2}Mn{sub 1/3}Ni{sub 1/6}O{sub 2} was synthesized by using a layered double hydroxides (LDHs) as precursor and solid state reaction method. Phase-pure LiCo{sub 1/2}Mn{sub 1/3}Ni{sub 1/6}O{sub 2} was obtained when the mixed precursors of NiMnCo-LDHs and LiOH.H{sub 2}O were calcined at 750 deg. C for 12 h. It showed discharge capacity of 180 and 148 mAh/g in the first cycle, corresponding to the discharge voltage ranges of 2.5-4.5 and 2.5-4.2 V, respectively, and still delivered 173 and 140 mAh/g after 60 cycles at room temperature, which represented favorable capacity retention upon cycling. This material was expected as a potential alternative of cathode material to be used for Li-ion secondary battery because of its good electrochemical performance and lower synthesis cost.

This paper reported the hydrothermal synthesis and thermal behavior of a novel kind of dawsonite-type solid solution K 1− x (NH 4 ) x Al(OH) 2 CO 3 ( x = 0.2–0.93). The effects of NH 4 + /K + molar ratio in the starting reactants and the hydrothermal reaction time on the composition of K 1− x (NH 4 ) x Al(OH) 2 CO 3 were investigated. In addition, the influence of the composition on the thermal stability of the solid solution was studied by DTA/TG analyses. It was indicated that compound K 0.44 (NH 4 ) 0.56 Al(OH) 2 CO 3 ( x = 0.56) is the most thermally stable one among all the dawsonite type solid solutions. Furthermore, K-β-Al 2 O 3 , a solid state K + ion conductor was prepared by calcining K 0.19 (NH 4 ) 0.81 Al(OH) 2 CO 3 at 1250 °C.

Dawsonite-type compounds of formula MAl(OH)2CO3 (M=Na,K,NH4) were hydrothermally synthesized. The influences of the composition of starting materials, reaction temperature, acidity of the reaction medium on the formation, morphology and particle size of MAl(OH)2CO3 powders were systematically investigated. The experiment results show that increase in the amount of MHCO3 favors the formation of MAl(OH)2CO3 phase with more slender particle morphology. The higher the reaction temperature, the grosser the particle is. It was also demonstrated that the particle size of the MAl(OH)2CO3 phase are most uniform when the pH value of reaction system is 10.3 for sodium dawsonite and potassium dawsonite, but it is 9.79 for that of ammonium dawsonite. The thermodynamics of the formation of dawsonite-type compounds have also been analyzed in details.