Li₂ZnTi₃O₈ anodes coated with N?doped carbon from dopamine hydrochloride were synthesized via a high?temperature solid?state method.Some Ti⁴⁺ ions were reduced to Ti³⁺ ions during synthesis,which enabled the co?modification of coating and doping.The modification method can enhance the ion diffusion coefficients and reduce the charge?transfer resistance.In the rate performance tests at 0.5,1.0,1.5,2.0,2.5,3.0 A/g,the specific capacities of N?doped carbon?coated Li₂ZnTi₃O₈(Li₂ZnTi₃O₈@C?N?2) are over 240.0，220.0，210.0，200.0，190.0，180.0 mA?h/g,respectively.In addition,the electrochemical performance of this material at a low temperature was also studied.The results show that the Li₂ZnTi₃O₈@C?N?2 sample has much higher discharge specific capacities than those of unmodified Li₂ZnTi₃O₈ anode material at 0 ℃.The initial discharge specific capacity is 262.5 mA?h/g at 0.2 A/g,and the discharge specific capacity of 241.7 mA?h/g is still obtained after 300 cycles.Even at 1.0 A/g,the discharge specific capacity is kept at 147.4 mA?h/g after 300 cycles.

Mg?Al?LDH was synthesized by the constant pH co?precipitation method,and the micro?structure and composition of the layered bimetallic hydroxides were characterized by X?ray diffraction (XRD),scanning electron microscopy (SEM),energy dispersive spectroscopy (EDS) and BET.The results show that LDHs were successfully prepared with a layered structure,a high degree of order,and mesopores.The toluene?n?heptane method was used to separate the asphaltenes in Tahe into heavy component A₁ and light component A₂.The elemental analysis indicates that A₁ had the highest polarity,followed by the Tahe asphaltenes and A₂.This paper further investigated the adsorption properties of Mg?Al?LDH for asphaltenes and their sub?components A₁ and A₂ in Tahe and found that the adsorption equilibrium can be reached within 2~3 h.The experimental data fitted well with the pseudo?second?order kinetics,and the adsorption isotherms followed the Langmuir model. The adsorption capacity of Mg?Al?LDH was 71.38,140.65 and 39.31 mg/g for asphaltenes in Tahe and their sub?components A₁ and A₂,respectively.

A combined chemical cleaning?thermal steam air floatation process was established to treat oil sludge,and the conditions of the combined process were investigated meticulously. Meanwhile, the self?synthesized WP?1 was taken as the main cleaning agent, and the cleaning effect of WP?1 was evaluated by the solid?phase oil content upon treatment. The results reveal that the optimal conditions for the combined process include a mud?to?water ratio of 1 : 3, a cleaning temperature of 80 ℃, an agitation rate of 200 r/min, cleaning time of 1.5 h, holding time of 15.0 min, and thermal steam air floatation of 1.0 h. Thermal steam air floatation solves the problem of suspending and sinking oil particles with large specific gravity in the cleaning process. Under optimal conditions, the solid?phase oil content decreases to 1.2%, meeting the oil sludge treatment standards stipulated in SY/T 7301-2016. The oil removal rate is as high as 92.08% when WP?1 is combined with 0.1 g of sodium silicate, which demonstrates a high price?performance ratio and is of good application value.

In order to investigate the oxidation and degradation effect of potassium on naphthalene,the main factors affecting the degradation rate of naphthalene were determined by single factor experiments,and the degradation conditions of naphthalene were optimized by response surface analysis.The results show that the best degradation condition of potassium ferrate for mass concentratoion of 5.0 mg/L naphthalene are as follows:the temperature is 25 ℃,the pH is 7.0, the dosage of potassium ferrate is 0.60 g/L,and the react time is 30 min.Under the optimum oxidation degradation condition,the rate of naphthalene is 75.60%.The results of single factor experiment show that pH(A),the initial mass concentration of naphthalene(B), and the potassium ferrate dosage(C) are the main factors affecting the degradation rate of naphthalene,and the degree of influence is from big to small C>B>A.The results of multifactor experiment show that the order of interfactors from big to small is AC>AB>BC.The model predicted the optimal degradation conditions of naphthalene by potassium perferrate:the temperature is 25 ℃,the initial mass concentration of naphthalene is 2.79 mg/L and the pH is 6.8,the mass concentration of potassium ferrate is 0.90 g/L,and the reaction time is 30 min.Under the optimum degradation conditions,the highest degradaton rate of naphthalene is 91.82%.

A nitrogen?doped carbon catalyst was prepared by the calcination of the CN _y precursor synthesized by the polymerization of paraformaldehyde,1,3,5?trimethylbenzene and p?phenylenediamine.This paper also investigated the effect of catalyst calcination temperature on the performance of acetylene hydrochlorination.The results indicate that CN _y ?700?1 catalyst has the best reaction activity.It has an acetylene conversion of up to 89.8% under the optimized conditions of acetylene?to?hydrogen chloride volume ratio of 1.0∶1.1,reaction temperature of 280 ℃ and GHSV(C₂H₂) of 90 h^-1.The catalyst characterization manifests that the activity of the catalyst is related to the specific surface area,pore volume,and pyrrole nitrogen content.The active site of the catalyst is the carbon atom bonding with the pyrrole nitrogen atom.Increasing the calcination temperature results in a larger specific surface area within a certain temperature range,and the pyridine nitrogen can also be converted to pyrrole nitrogen to a certain extent.The main cause of catalyst deactivation is carbon deposit.

Layered double hydroxides (LDHs),also known as hydrotalcite,can be widely employed in water pollution treatment because of their special layered structures,high physicochemical stability,and electronic properties.The application of LDH composites as catalysts for photocatalysis has received increasing attention.Therefore,the preparation and modification of LDH photocatalysts were reviewed,and the removal effect of pollutants from wastewater exerted by different LDHs was emphatically introduced.In addition, the mechanism and research status of LDH photocatalysts were briefly described.Finally,the development trend of LDH photocatalysts was prospected to provide a reference for the subsequent application of LDHs in water pollution treatment.

A ZnO nanoflower hybrid material loaded with NiO nanoparticles was presented,and then it was investigated in XRD, morphology and gas sensing properties.The results show that surface loaded NiO nanoparticles modulated the electric channel of ZnO nanoflowers.The response value of heterojunction gas sensing material with optimized NiO loading amount to xylene is increased by 3.3 times compared with that of pristine ZnO.In addition,the selectivity of the sensor is enhanced and response time decreases.From a broader perspective,the methods for functionalized gas sensors of high?performance semiconductor metal oxide (SMOX) are proposed by introducing surface heterostructure.

A new type of gelator with π?π stacking as weak interaction force was designed and synthesized. Pyromellitic acid esters were synthesized from pyromellitic dianhydride and alcohols of different carbon chain lengths to reduce hydrogen bonding sites.Then the gel capabilities were explored in common different organic solvents.The rheological test shows that the elastic modulus of the gel system is ten folds higher than the storage modulus,indicating that the gel has good mechanical properties and exhibits typical solid?like rheological behavior.Fourier transform infrared spectroscopy,nuclear magnetic resonance spectroscopy,scanning electron microscopy and DSC results show gelators formed fibrous self?assembled aggregates in gel under driving force from π?π stacking and the van der Waals force.The formed aggregates entangle with each other and finally form a three?dimensional network structure that hinders the flow of the solvent to form the gel.

Common wicker,the raw material of biochar,was treated by hexadecyltrimethylammonium chloride (CTMAC) for cationic surface activation,and then it was mixed with zero?valent iron and sodium alginate to prepare zero?valent iron/cationic surfactant/biochar (Fe⁰?MBC) gel microspheres, and their ability to adsorb Cr(VI) in water was discussed.The structure and properties of Fe⁰?MBC gel microspheres were studied by means of XRF,FTIR,XRD and Zeta potential.Upon the analysis of the effects of the reaction time,temperature and pH value on adsorption,the adsorption mechanism was preliminarily discussed on the basis of adsorption kinetics and the isotherm model.The results indicate that the adsorption effect of Fe⁰?MBC gel microspheres on Cr(VI) is highly fitted with that of pseudo?first?order kinetics and the Langmuir isothermal adsorption model. The removal rates of Cr(VI) by CTMAC?activated biochar loaded with 5% zero?valent iron and CTMAC?activated biochar loaded with 10% zero?valent iron can reach 89% and 97% (initial Cr concentration of 100 mg/L) at 2 h, respectively, and the maximum saturated adsorption capacities are 33.777 9 mg/g and 42.562 0 mg/g, respectively.The experimental results reveal that Fe⁰?MBC gel microspheres, as a low?cost and high?efficiency environmental functional material, have good application prospects for the removal of Cr(VI) in wastewater.

The strong stress sensitivity of low permeability oilfield reservoirs leads to serious permeability loss,larger starting pressure gradient,and higher seepage resistance,thereby reducing the water?flooding effects of oilfields.The existing prediction models for water breakthrough time do not consider the stress sensitivity and variable starting pressure gradient at the same time,which results in inconsistency between calculation results and actual situation of mines.Therefore,for the first time,this paper deduced the prediction models for the water breakthrough time of well pattern of five point method,four point method,and inverse nine point method in the condition of unequal row spacing and well spacing considering stress sensitivity and variable starting pressure gradient.The calculation results show that the error of the new model is relatively small,which is more in line with the field practice.The results can guide the adjustment of block measures and provide theoretical support for improving the development of water drive oilfields.

As an important method of reservoir parameter calculation and single well controlled reserves evaluation, production decline analysis has been widely used in conventional and unconventional reservoir evaluation and dynamic reserve calculation. However, researches on heavy oil reservoir production decline analysis model have rarely been reported. Therefore, based on the unsteady seepage theory, an unsteady mathematical model of radial composite reservoir with Newtonian and power law fluid is established to get NPI and Blasingame production decline characteristic curves. The results show that the characteristic curves can be divided into four flow stages, including Newtonian fluid radial flow stage, transition flow stage, power?law fluid radial flow stage and pseudo?steady?state flow stage. The NPI integral derivative curve of power?law fluid radial flow stage is a straight line with slope of (1-n)/(3-n). The higher the power?law index and mobility ratio indicates the larger value of power?law fluid flow phase curve. The accuracy of the model is verified by fitting the measured data from Liaohe Oilfield.

A high tide velocity makes it difficult for the riser to enter the borehole during its running after the riser section is drilled. A finite?element fluid?solid coupling model of fluid (seawater) and solid (casing) interaction is built with the finite?element analysis software ADINA. The following observations can be made from the analysis. A higher velocity results in a larger lateral offset in the final equilibrium state when the riser enters the borehole.Due to the flow blocking effect of the riser, seawater near the front end of the riser produces a strong detouring flow, while a local vortex is observed in the area near the back end of the riser.Under four working conditions of different tide velocities (0.60,0.70,0.80 and 0.90 m/s), both the Reynolds number and the equivalent flow resistance coefficient are in reasonable ranges.When the borehole diameter reaches 889.0 mm after borehole enlargement, a 508.0 mm riser is run in. No obstruction is encountered when the tide velocity is less than 0.59 m/s, whereas difficult borehole entering occurs when the tide velocity is higher than 0.83 m/s. It is suggested that the riser will be run in when the tide velocity reduces to below 0.59 m/s. The simulation analysis has a great guiding significance for the running of the riser during the drilling of offshore oil fields.