To investigate the effect of donor unit length on the thermoelectric properties of D-A conjugated polymer,three D-A conjugated polymers(PDPP-DTP,PDPP-2DTP,PDPP-3DTP) based on dithieno[3,2-b:2′,3′-d]pyrrole (DTP) with different donor unit lengths were designed and synthesized.The influence of donor unit lengths on the energy levels of the polymers was studied by electrochemical characterization and density functional theory calculations.With ferric chloride as dopant,the polymer films were oxidation doped.Their optical and thermoelectric properties as well as the temperature dependent resistance were discussed.The results show that the HOMO energy levels of the polymers gradually increase with the extension of the length of the DTP-like donor unit,which makes them easier to be oxidatively doped.At the same dopant concentration,the doped polymers exhibit higher conductivity with the extension of the donor unit length.Among them,PDPP-3DTP shows the highest electrical conductivity of 302.3 S/cm,which is much higher than that of PDPP-2DTP(106.2 S/cm) and PDPP-DTP(64.7 S/cm).The charge transport energy barrier of the polymer films gradually decreases with the extension of the length of the donor unit,which is beneficial for the enhancement of electrical conductivity of doped films.However,the Seebeck coefficient of the doped polymer film decreases with the extension of the length of the donor unit,and the final polymer PDPP-2DTP is doped and optimized to have the highest thermoelectric power factor of 19.4 μW/(m·K2).
Two nonionic surfactants were synthesized using N-dodecylsuccinic anhydride, L-leucine, and polyether alcohol as materials. In order to study the aggregation morphology and properties of these two surfactants, their surface tension at different concentrations was tested and the critical micelle concentration (CMC) was determined based on the γ-lgc curve. The molecular dynamics simulation techniques was used to study the aggregation pattern of surfactants at the oil-water interface and the interaction with oil and water. The results showed that compared to surfactant 1,surfactant 2 had more nonionic hydrophilic components and thus reducing surface tension was more effective. The critical surface tensions (γCMC) of surfactant 1 and surfactant 2 were 25.54 and 24.46 mN/m. At low concentration, both of the two nonionic surfactants have high water precipitation rate and poor emulsification effect, but at high concentration, the emulsification effect is better, and the lotion prepared with two nonionic surfactants has certain stability. The electrostatic potential distribution of surfactant molecules affects their hydrophilic and oleophilic properties.
Cyclohexylbenzene (CHB) is an important chemical intermediate with special physicochemical properties.It can be used as electrolyte additive for lithium ion battery. A small amount can prevent overcharging and ensure battery cycle performance and life. CHB can generate another important organic chemical product, cyclohexanone, when used in the synthesis of phenol through peroxidation reaction. Introduced the catalysts used in three methods for synthesizing CHB. These three methods include Fouke alkylation of benzene with alkylation reagent, selective hydrogenation of biphenyl, and alkylation of benzene with hydrogen. It is pointed out that the development of zeolite molecular sieve catalysts with high acid content and high mesoporous volume is the key to the preparation of CHB by benzene hydroalkylation.
Compared with the commonly used gas-liquid bubble tower, the tubular gas-liquid contactor has the advantages of high gas content rate, low energy consumption and simple maintenance to strengthen the gas-liquid mass transfer process by generating a uniform bubble-like and highly dispersed system in the pipeline space.A micro-bubble type tubular gas-liquid contactor was developed independently which utilizes the high-speed shear crushing effect of a venturi jet bubble generator to generate micro bubbles.Based on computational fluid dynamics (CFD) numerical simulation and indoor experiments,the bubble formation mechanism and bubble size distribution of the micro bubble tubular gas-liquid contactor were investigated.The results show that the VOF multiphase flow model coupled with RNG k-ε turbulence model can simulate the jet impingement process and bubble formation characteristics. In the expansion section of the venturi jet bubble generator,large bubbles are sheared and broken into micro bubbles, and the bubbles are uniform and stable. The particle size of bubbles decreases with the increase of liquid volume, and the particle size of bubbles is the smallest (76.5 μm) when the liquid volume is 14.0 L/min, the gas volume is the maximum natural suction volume, and the length of the column is 800 mm. The bubble particle size increases with the increase of gas volume, and is the smallest (86.7 μm) when the gas volume is 1.5 L/min, the liquid volume is 8.0 L/min, and the length of the column is 800 mm.As the length of column increases, the bubble size first decreases and then remains basically unchanged. When the column length is greater than 800 mm, its impact on the bubble particle size is relatively small.
Estuary bar sandstone body is also one of the most important types of oil and gas reservoirs in China,and its internal interlayers control the distribution and movement of fluid inside the reservoir and affect the overall development effect of the reservoir. Taking the fault block reservoir of Sha-2（S2） member of L11 fault block in Shinan oilfield as an example, the rock and layer type of intercalation in estuary bar sandstone body are analyzed by means of logging, core, analysis and dynamic production data, the spatial distribution law of intercalation is described, and the influence of intercalation on remaining oil distribution is expounded.The results show that the main oil layer of L11 fault block consists of mud, physical and calc interlayers, which account for 68%,21% and 11% respectively.The calc interlayers are concentrated in the distribution area of physical interlayers,and the development degree of physical interlayers is relatively high in the northeast near the provenance and the peak of the interlayer, while the development degree of mud interlayers is relatively high in the southwest far from the provenance. In the near-source direction, the fifth-order configuration interface is relatively thin, and in the far-source direction, the thickness is relatively thick, ranging from 0.60 m to 29.00 m. In the fourth-order interface, the drilling rate of interlayer is above 60%, the thickness is between 0.35 m and 4.10 m, and the inclination is less than 2.0°. The level 3 interfacial interlayer is spread no more than 3 well spacing, the thickness is less than 1.50 m, and the dip angle is 2.7° on average. Level 4 and 5 interfaces control the distribution of remaining oil,level 3 interface has little influence on the distribution of remaining oil, low injection and high production mode development effect is relatively good,high injection and low production mode development effect is relatively poor,through the injection and production mode can improve the well group oil displacement efficiency and development effect.The above results and understanding have important guiding significance for the efficient development of estuary bar sandstone reservoir.
In order to extend the life cycle of super 13Cr stainless steel tubing in ultra-deep wells and reduce the stress corrosion caused by complex drilling and completion fluids and formation output fluids during the production process, a stress corrosion generation mechanism analysis has been carried out and a countermeasure strategy has been put forward.Based on the corrosion inhibition mechanism of polymerized film-forming corrosion inhibitor, a corrosion inhibitor has been developed. The stress corrosion of super 13Cr stainless steel has been evaluated in the acid fluids and the return fluids with/without the corrosion inhibitor in the simulated and standard conditions. The results show that the acid solution with corrosion inhibitor met the corrosion inhibition requirements. The macroscopic corrosion rate of super 13Cr stainless steel in the return fluids was larger. There was stress corrosion in the acid solution and the return fluids, and the stress corrosion of the return fluids was more serious.Under the experimental temperature of 140 ℃ and pressure of 10 MPa, the stress corrosion crack width of super 13Cr stainless steel in the return fluids after one week was 3~5 μm,test 72 h after the addition of corrosion inhibitor with a volume fraction of 1%, super 13Cr stainless steel test piece did not produce stress corrosion, which indicated that the corrosion inhibitor could restrain the stress corrosion cracking of super 13Cr stainless steel in the high temperature environment. The result of study is of great significance for the safe construction and safe production of ultra-deep well drilling and completion.
Powder electrocatalysts usually need adhesives for electrocatalytic performance testing,resulting in an increase in resistance,a decrease in catalyst load,and easy stripping of the catalyst under long-time testing.Ce-doped CoFe layered bimetallic hydroxides were uniformly grown on carbon cloth by one-step hydrothermal method,and the adhesive-free Ce-CoFe-P@CC self-supporting electrocatalyst was obtained by further phosphating treatment.It was characterized by XRD,SEM,TEM,N2 adsorption-desorption isotherm and XPS,and its electrocatalytic OER performance was tested.The results show that the synthesized electrode material has regular thin nanosheet morphology,and the length and thickness of the nanoflake are 2.50 μm and 0.05 μm, respectively.The doping of Ce and P optimizes the electronic structure of CoFe-LDH,promotes the charge transfer,increases the catalytically active site,and improves the durability of the electrode.The Ce-CoFe-P@CC only needs an overpotential of 187 mV at a current density of 10 mA/cm2,showing excellent OER catalytic performance.
In order to study the correlation between the mass transfer performance of fluid catalytic cracking (FCC) catalysts and their pore structure and acidity,three semi synthetic FCC catalyst samples(CAT1,CAT2,CAT3) with different pore structure and acidity were prepared.Naphthalene,phenanthrene and acridine were selected as probe molecules to test the adsorption penetration performance of the guest molecules on the catalysts and to investigate their mass transfer performance.The ability of acid center conversion on catalysts was visualized and analyzed using super-resolution imaging technology.The results show that effective discrimination of the differential adsorption behavior of FCC catalysts for macromolecules can be achieved by selecting suitable probe molecules.The mass transfer performance of macromolecules on FCC catalysts depends on the pore structure and surface acidity of the catalysts.The use of novel macroporous matrix materials optimizes the mass transfer performance of FCC catalysts and enhances the acid on Y molecular sieves in FCC catalysts centers in FCC catalysts.The work can provide an effective solution for studying the mass transfer structure-activity relationship of FCC catalysts,and also provide theoretical guidance for the design of efficient FCC catalysts.
The two-dimensional metal-organic framework nanosheets represent a novel class of two-dimensional materials, featuring a more exposed active site,rapid proton or electron transfer,and other advantages than bulk materials.It is a major challenge to prepare two-dimensional metal-organic framework crystalline materials that are easy to peel off into two-dimensional metal-organic nanosheets at present.In this paper,two novel nickel based two-dimensional metal organic framework crystalline materials Ni(C9H3O6)(C4H6N2)2·0.6(C2H5OH)(1) and Ni3(C9H3O6)3(C5H8N2)6·3.25(C2H5OH)(2),were prepared by a simple one-pot method using cheap and less toxic ethanol as the reaction medium,trimesic acid and N-imidazole as common ligands,and characterized and exfoliated.The reaction medium used in the experiment,ethanol,is less toxic, cheap, less polluting to the environment,and can be recycled,which meets the requirements of green chemistry.This shed light on the design and synthesis of crystalline peelable two-dimensional metal-organic framework crystal materials.
Heterogeneous Mn3O4/CuMnO2 catalyst CMO-A is prepared by a one-step hydrothermal method using cupric chloride dihydrate and manganese chloride tetrahydrate as raw materials.The composition of the samples prepared at different temperatures is analyzed by X-ray diffraction analysis.Using mercury lamp as light source and 50 mg/L Rhodamine B(RhB) solution as contaminant model,the photo-Fenton reaction performance of the prepared CMO-A sample is tested.The results show that CMO-150 has the best degradation effect on RhB solution when the reaction temperature is 150 ℃,and the degradation rate reaches 98.01% when the reaction time is 15 min.The optimal reaction conditions and cyclic stability of CMO-150 catalyst are investigated.The experimental results show that the optimal reaction conditions are 0.2 mol/L H2O2,50 mg CMO-150 catalyst,50 mg/L RhB solution and pH=3.0.After 5 cycles,the degradation rate only decreases by 22.24% at 15 min.The main active species in the reaction is hydroxyl radical (·OH) through the sacrificial agent experiment,and the reaction mechanism is explored by combining with the control experiment.
