This paper summarized the separation effects of different electrodialysis systems on lithium in Salt Lake, including single selective electrodialysis, ionic liquid membrane and bipolar membrane, among which ionic liquid membrane with a broad development prospect possesses the characteristics of high recognition of Li⁺, long?term stability under electrolysis and low energy consumption. Furthermore, the advantages, disadvantages and tendency of prospective development of different electrodialysis systems in lithium extraction from Salt Lake were analyzed, and the industrialization research on the application of electrodialysis systems for lithium extraction from Salt Lake was analyzed.

Shale hydration and dispersion lead to instability of the borehole wall, which has always been a problem in oil and gas drilling engineering. Physically plugging pores and micro?cracks in shale through nano plugging agents is the best way to improve the stability of shale formations. In this work, the silane coupling agent KH560 was used to modify the high?concentration silica sol. The principle of soap?free emulsion polymerization was used in combination with solvothermal synthesis to graft acrylic acid (AA) and styrene (St) monomers on the surface of modified SiO₂ particles. Thus, a new type of elastic pressure?bearing plugging agent with polymer?encapsulated nanoparticles was successfully developed. Taking medium pressure filter loss as the evaluation index, the best synthesis conditions were obtained: The reaction temperature was 60 ℃, the reaction time was 3.0 h, the monomer ratio was 3∶2, the pre?emulsification time was 10.0 min, the total monomer mass was 6.67%, and the amount of initiator was 0.40%. In addition, Zeta potential, particle size analyzer and transmission electron microscope proved that the median particle size of the prepared STA?1 plugging agent was 45.3 nm. Finally, a core displacement experiment was used to simulate the shale layer to investigate the actual plugging effect of STA?1. The results revealed that 1.00% STA?1 showed good water plugging ability for sand filled pipes with permeability below 2 000 mD, and the plugging rate was higher than 85%.

Iridium (III) complexes have broad application prospects in luminescence detection of analyte due to advantages of large Stokes shift, high quantum yields, long luminescence lifetimes, flexible and adjustable emission spectra, and excellent optical and thermal stability. The novel iridium(III) complex Ir(ppyTPA)₃ was prepared by introducing triphenylamine substituent on 2?phenylpyridine, and the structure, luminescence and electrochemical properties of Ir(ppyTPA)₃ were characterized in detail. Then, the luminescence properties of Ir(ppyTPA)₃ were used to detect five common nitroaromatics and the detection mechanism was studied. The results show that Ir(ppyTPA)₃ has the highest detection efficiency to 3?nitrobenzoic acid with the detection efficiency constant K_SV of 19.78 L/mmol. And the detection limit is as low as 2.89×10^-3 mol/L. Spectral analysis and density functional theory calculations show that the detection mechanism of Ir(ppyTPA)₃ for the five nitroarenes was the charge transfer mechanism.

Solid oxide fuel cells (SOFC) as one of the energy conversion devices, have received widespread attention and importance from all walks of life because of its clean and efficient operation. Anode is an important part of SOFC. It is important to find anode materials with good fuel catalytic activity in SOFC field. In recent years, molybdat?based perovskite materials as SOFC anodes show excellent conductivity and electrochemical properties at low and medium temperatures, and have been extensively studied by many research groups. In this paper, the research progress of molybdate?base perovskite as SOFC anode is reviewed, and the effects of different doping conditions on the properties of materials are summarized from the theoretical and experimental results, so as to provide guidance for the future research of materials.

In this work, the rutile mesocrystals TiO₂ were synthesized by hydrothermal method using layered titanate HTO (H_4x/3Ti_2-x/3□ _x/3O₄?nH₂O) as the precursor. By means of X?ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and other testing methods, the effect of reaction temperature on the synthesis of rutile?type mesoscopic TiO₂ crystal material by means of topological structure transformation was studied. The results reveal that rutile TiO₂ can be obtained under the condition of pH 0.5 of the reaction system, and with the gradual increase of the reaction temperature, the rutile?type mesoscopic TiO₂ crystal material is formed at 120 ℃. Taking Rhodamine B (RhB) as the pollutant model for degradation experiments, the photocatalytic activity of rutile mesocrystals TiO₂ is significantly higher than that of other samples. Experiments on dye?sensitized solar cells (DSSCs) show that the mesocrystals structure formed at 120 ℃ is conducive to the rapid migration of photogenerated carriers, thus obtaining high cell characteristics.

As a universal low temperature gathering and transportation boundary condition,the wall sticking occurrence temperature (WSOT) has been widely promoted and applied in the oilfield in the late stage of high water cut development. When the oil gathering temperature is higher than the WSOT, the pipeline operates smoothly, otherwise the pressure drop of most pipelines increases significantly, but some of the pipeline pressure drop changes are not obvious. Through the field cooling experiment, it was found that in the process of the oil gathering temperature gradually decreasing to 6,8,10 ℃ and 12 ℃ below the gel point, the wellhead back pressure has experienced four stages of smooth operation, small fluctuation, low frequency large fluctuation and high frequency large fluctuation, and there are several "restart" processes in the pipeline when the gathering temperature is too low. At the same time, the gas injection experiment under different gas?oil ratio was further carried out, and the results show that when the gas?oil ratio is 40,80,160 m³/t, the pipeline can run stably at the gathering temperature 3,4 ℃ and 6 ℃ lower than the WSOT.

In the environment of CO₂ enhanced recovery (CCS?EOR), the corrosion cracking behavior and mechanism of X70 pipeline steel under different CO₂ pressures were studied. The on?site environment was simulated by using a high?pressure reactor and a simulated produced aqueous solution; the corrosion rate and corrosion mechanism of X70 pipeline steel in the CCS?EOR environment were investigated by electrochemical experiments; the corrosion cracking behavior of X70 pipeline steel under simulated environment was investigated by slow strain rate tensile experiments; finally, the corrosion cracking behavior of X70 pipeline steel under different CO₂ pressure was analyzed by scanning electron microscope. The results show that the corrosion rate of X70 pipeline steel increases with the increase of CO₂ pressure; the corrosion product film produced on the surface of X70 pipeline steel can not protect the metal matrix, and intensify the local corrosion; under the influence of the corrosion product film, the increase of CO₂ pressure makes X70 pipeline steel stress corrosion susceptibility increases; and the corrosion cracking of X70 pipeline steel is also affected by the metal surface cracks.

Energy shortage and environmental pollution have always been the focus of the world's attention. The use of oil, natural gas, and electricity to heat crude oil has high energy consumption and serious environmental pollution. Solar energy, as sustainable and clean energy, has become the focus of researchers from all over the world.Thus, a solar heating crude oil system was designed, and safe and easily available air was selected as the heat transfer fluid. The system consists of a solar receiver, a heat accumulator, a crude oil heat exchanger, and an electro?thermal furnace. The heat receiver receives solar radiation and the temperature rises. The air passes through the heat absorber to obtain high temperature, and the high temperature air enters the heat exchanger to heat the crude oil. A mathematical model for the analysis of the thermodynamic performance of the solar heating crude oil system was established, and the model was verified. Then, the Aspen Plus software was used to conduct thermodynamic analysis of the heatingprocess. The results show that the compressor and the preheater are the components with large exergy loss. When the pressure ratio of the compressor is 2.7, the system reaches its best state. At this situation, the thermal efficiency is 72.35%, the exergy efficiency is 73.89%, and the waste heat recovery efficiency is 72.33%.

The Al?15Si?xNb coating was used as the research object to explore the effect of Nb content on the microstructure and corrosion resistance of the coating. The microstructure of the coating was observed by metallographic microscope, the phase composition of the coating was analyzed by XRD, and the corrosion behavior of the coating in 3.5% NaCl solution was characterized and discussed by electrochemical experimental methods (including open circuit potential, impedance spectrum analysis and polarization curve analysis). The results show that the Al?15Si?xNb coating is mainly composed of α?Al, primary Si and eutectic Si. A small amount of NbAl₃ phase and Nb₅Si₃ phase are formed after Nb element is added to the coating; The addition of Nb promoted heterogeneous nucleation and significantly changed the microstructure distribution of the coating. The microstructure of Al?15Si?10Nb coating has a homogeneous distribution. Uniformly distributed α?Al, primary Si and eutectic Si will form many uniformly distributed corrosion micro?battery. It can promote Al anodic reaction and make the Al₂O₃ oxide film formed on the coating surface more continuous. The polarization curve of Al?15Si?xNb coating has passivation like characteristics. When 10% Nb is used, the self?corrosion potential and pitting potential of the coating are higher, the product film resistance is larger, and the dimensional passivation current density is lower. Therefore, Al?15Si?10Nb coating has better corrosion.

Screw geometry has an important influence on the mixing characteristics of single screw extruder. Three kinds of six rhombic thread elements, four rhombic thread elements and tooth thread elements with special configuration were selected to design three new combined screws of single screw extruder for different processing requirements, and the flow and mixing characteristics of polylactic acid in the three combined screws were studied. The results show that there is a large pressure gradient at the pressure junction of the combined screw, the diamond thread element can provide high tensile action for the material, the residence time of the fluid in its channel is short, and the mixing performance is relatively poor; the toothed screw element can not only provide high shear effect but also high tensile effect for materials, with long residence time and good mixing effect.

High?speed tensile tests of HC420/780DP dual?phase steel at strain rates of 0.001，0.100，1.000，10.000，100.000 s^－1 and 200.000 s^－1 were carried out. The dynamic mechanical behavior of the materials under different strain rates was studied. The true stress?strain curves of HC420/780DP at different strain rates were obtained, and the fracture elongation, tensile strength and flow stress were analyzed. The results show that the flow stress, yield strength and tensile strength of HC420/780DP dual?phase steel increased with the increasing strain rate. Based on the modified Johnson?Cook constitutive model, the dependent plastic deformation constitutive model versus HC420/780DP dynamic strain rate was established. The fitting results of the optimized constitutive equation are in consistent with the curves of experimental results.

The dry point of gasoline is difficult to be measured in real time. A large number of data samples need to be extracted to test the quality of each section of the oil. In order to solve this problem, predictive control was carried out by establishing a soft sensor model. The least squares support vector machine model is too sensitive to outliers, which is easy to affect the prediction accuracy. By establishing the weighted least squares support vector machine model (WLSSVM), the fitting error is weighted, which weakens the influence of outliers on the model and improves the anti?interference ability of the model. The improved WLSSVM was applied to the prediction of gasoline dry point. The results show that the maximum absolute error of the improved WLSSVM is 11.65% lower than that of the least squares support vector machine model, and its prediction performance and robustness have obvious advantages.

Aiming at the problem of temperature tracking and balance control of each branch pipe of the heating furnace, an improved genetic algorithm was proposed to optimize the multi?deviation control of the temperature tracking and balance of the branch pipe temperature of the heating furnace. The scheme used the temperature deviation of the raw materials of each branch pipe after mixing and the temperature deviation of each branch pipe. By adjusting the feed flow rate and fuel flow rate, it not only ensured that the flow rate of the main pipe is constant during the regulation process, but also realized the dual goal of temperature tracking and balance of each pass. Multi?passes are analyzed as a whole, so the temperature comparison of adjacent branch pipes was avoided repeatedly. At the same time, the improved genetic algorithm was used to optimize the controller parameters of the differences control technique, which overcomes the difficulty of controller parameter tuning. The simulation results show the feasibility and effectiveness of the improved genetic algorithm to optimize the differences control scheme.

For the MIMO nonlinear systems, a multivariable ORVFL neural network adaptive predictive control algorithm based on Improved Sparrow Search Algorithm was proposed in this paper. The algorithm uses the ORVFL network to approximate the nonlinear system model, and applies to the multi?step prediction of the system process. In order to improve the performance of the Sparrow Search Algorithm, the algorithm is used to optimize the system performance index online and solve the optimal control law of each sampling period. The results show that the algorithm has good control performance and good anti?model mismatch ability.

Gaussian mixture model (GMM) is easily affected by noise, and Markov random field (MRF) model can well describe the spatial characteristics. The combination of the two is suitable for image segmentation with noise, but MRF model is prone to over segmentation. To solve this problem, an improved image segmentation algorithm based on adaptive weight coefficient was proposed, which can segment cerebrospinal fluid, gray matter and white matter from magnetic resonance imaging (MRI). Firstly, the K?means algorithm was used to obtain the initial segmentation results, and the Expectation?Maximization (EM) algorithm was used to estimate the parameters of GMM, and then the joint probability energy function of the pixel gray level of the image was obtained. Then, the adaptive weight coefficient was obtained by using the gray value, posterior probability and Euclidean distance of the center pixel and the neighboring pixels of the MRF neighborhood system, and the prior probability energy function was obtained by MRF. Finally, the final image segmentation results were obtained by Bayesian criterion. Experimental results show that the algorithm has strong adaptability, can better overcome the impact of noise on image segmentation. Compared with similar algorithms, the proposed algorithm has higher segmentation accuracy for brain MR images with noise, and obtains better segmentation results.

The solidifying point of shale oil is high, and the wax content is high and the emulsification degree of shale oil is high. As a result, it is not easy to dehydrate shale oil emulations by using the traditional thermochemical method, which is difficult to meet the export standard. High frequency pulse dehydration technology is an effective method to dehydrate, but there are few studies on the optimization of treatment parameters of shale oil produced fluid. In this study, the effect of high frequency pulse dehydration technology on Dagang shale oil emulsion was studied, and the treatment parameters were optimized. The results show that high frequency pulse dehydration technology can achieve effective demulsification of shale oil produced liquid and significantly reduce the water content of shale oil. Through the comparison and selection of treatment parameters, it is found that the increase of electric field intensity and electric field frequency is conducive to improve the dehydration efficiency. Besides, there are electric field action time, operation temperature and demulsifier concentration parameters with the best dehydration efficiency. It is proposed that under the electric field strength of 200 kV/m, electric field frequency of 5 kHz, electric field action time of 60 min, operating temperature of 75 ℃, demulsifier mass fraction of 0.010%, the water content of shale oil after dehydration is 0.48%, and the comprehensive benefit is the best. The research results provide technical support for the optimization of shale oil produced fluid treatment parameters.

In order to realize the resource disposal of surplus sludge from sewage treatment plant, ordinary silicate cement was used to solidify it as a building material. The surplus sludge and cement were mixed evenly according to a certain ratio and placed in a standard curing box for 3~28 days. The unconfined compression strength (R_C) and total organic carbon (TOC) content of the sludge?cement consolidated body were used as evaluation indicators. It was found that the R_C of 28 days for surplus sludge?cement solidified block could reach about 6.9 MPa when mass ratio (R_m) of surplus sludge to ordinary silicate cement and mass ratio (R_l/s) of liquid to solid are 0.63 and 0.31. The R_C can't meet the minimum strength requirement of non?sintered brick, but meets the strength requirement for surplus sludge landfill. The total organic carbon value in leached solution (TOC_l) of surplus sludge?cement solidified block decreased by about 86% compared with the initial value (TOC₀) in consolidated block. It indicates ordinary silicate cement solidified surplus sludge can effectively solidify organics from surplus sludge in the solidified body, which can effectively inhibit the secondary pollution of surplus sludge for land in the landfill treatment process.

In this paper, the method of combining Grand Canonical Monte Carlo simulation and Ideal Adsorption Solution Theory was used to study the adsorption performance of CO₂ and CH₄ on NaX zeolite. By comparing the fitting results of simulation data under different adsorption theoretical models and calculating the adsorption heat, a description of the adsorption and separation process of CO₂ and CH₄ gas was obtained. The results show that the adsorption strength of CH₄ molecules is weaker than that of CO₂ molecules, and its adsorption is closer to the ideal adsorption. The adsorption selectivity of CO₂ molecules is decreases with the increase of its content in the air, and decreases with the increase of temperature under low pressure conditions. Therefore, low temperature and low pressure are more conducive to the separation of CO₂ molecules.

In this paper, the extraction process of flavonoids from Ligusticum was optimized by single factor test and response surface methodology, and the antioxidant experiment in vitro was carried out. The optimum extraction conditions were as follows: extraction time 2.5 h, extraction temperature 83 ℃, ethanol concentration 84%, liquid?solid ratio 35 L/g (the ratio of ethanol volume to Ligusticum jeholense powder sample mass). Under these conditions, the yield of flavonoids from Ligusticum was （22.64±0.18） mg/g. The results of antioxidant experiment in vitro showed that flavonoids from Ligusticum had certain antioxidant capacity. The clearing effect of ·DPPH is the best, the clearing effect of ·OH is the second, and the clearing effect of·O^2- is the worst. It also has the ability to restore Fe³⁺.

In this study, nano?TiO₂ was used as the additive phase, and B₂O₃ and H₃BO₃ were doped in a certain proportion, and then 4% nano?oxide particles reinforced Al matrix composites were prepared by high?energy ball milling and powder metallurgy. Finally, Al matrix composite rods were prepared with an extrusion ratio of 16∶1 at 723 K. The results show that the dispersion distribution of nano?oxides in Al matrix can be realized after 4 h ball milling. After vacuum hot pressing at 893 K, the addition phase reacts with the Al matrix in?situ and forms Al₂O₃ etc. When the molar ratio of Ti to B is 1.0∶1.5, the mechanical properties of the composites are the best. At the same time, when the chemical composition of the precursor of B element is different, the mechanical properties of the composites are significantly different; the tensile strength of TiO₂+H₃BO₃/Al at room temperature and 623 K is 507.7 MPa and 151.3 MPa, respectively, showing the highest room temperature mechanical properties; the tensile strength of TiO₂+B₂O₃/Al at room temperature and 623 K is 353.7 MPa and 167.1 MPa, respectively, manifesting the excellent high?temperature mechanical properties.

Proton conductive materials are an important part of sensors and fuel cells. In recent years, the research of crystalline proton conducting materials has mainly focused on metal organic framework material(MOF). Lanthanide metal organic framework (Ln?MOF) is an important member of the MOF family, and it is easy to form a stable and diverse framework owing to the strong coordination ability, Lewis acidity and complex functionality of lanthanide ions. At present, people are beginning to focus on its research in the field of proton conduction. This article reviews the research progress in proton conduction of Ln?MOF materials with different functional acid groups (carboxylate, phosphonate or sulfonate groups, etc.) introduced into the main frame. The challenges faced by Ln?MOF materials in the study of proton conduction were prospected.

Most of the oil fields in China have entered the middle and late stage of exploitation, and the well produced fluid has a high water content. FRP pipes are widely used in surface gathering system of oilfield because of their excellent corrosion resistance. At the same time, in order to save heating energy, low?temperature transportation process can be used to transport high water?cut crude oil, but the possible adhesion problem of crude oil is a serious threat to system safety.Therefore, it is important to investigate the interfacial properties of FRP pipe wall/crude oil to reveal the adhesion mechanism of low?temperature transportation of crude oil with high water?cut. The interfacial properties of crude oil on the FRP surface and stainless steel surface were investigated based on the contact angle apparatus. In the aqueous phase, the contact angle of oil droplet on the solid surface increased with decreasing temperature, and the contact angle of oil droplet on the FRP surface is larger than that on the stainless steel surface. The interfacial tension of oil droplet increased with decreasing temperature in the aqueous phase, and compared to the stainless steel surface, the adhesion work of oil droplet on the FRP surface is lower. And the cohesion work of oil droplet decreased with increasing temperature in the aqueous phase. Crude oil is not easy to adhere to the FRP pipe in the gathering system, FRP pipe is more conducive to the implementation of low?temperature transportation process.

Standalone screen sand control method is one of the most commonly used sand control method for oil and gas wells. With the deepening of oil and gas field development, the working environment and its own conditions of the independent screen sand control system have changed. Affected by high temperature and high pressure, external load, corrosion, fluid erosion and other factors, it is easy to cause sand control failure, which seriously affects the normal production of oil and gas wells. In this paper, long?term mine practice and theoretical analysis are taken to investigate the reasons for sand control failure. It is considered that the main causes of sand control failure are sand control packer failure, sealing mechanism failure and sand control screen tube failure, among which sand control screen tube failure is the most likely to occur. Screen erosion, screen corrosion, geological factors and special operations are the main factors leading to the failure of sand control screen. Through the in?depth analysis of the causes of sand control failure in oil and gas wells, it provides an important basis for taking preventive measures to avoid sand control failure and affecting production.

Aiming at the problem of wax deposition in gas well exploitation of offshore HPHT gas reservoir, the gas?liquid?solid and fluid phase equilibrium theory and method of throttling effect principle was used to reveal the wax deposition mechanism of the abnormal high temperature and high pressure gas well, and it was found that wax deposition in high temperature and high pressure gas wells mainly occurs at the position of the oil nozzle where the temperature drops sharply when the wing valve of the gas well is closed. According to the phase equilibrium theory, the phase state of the original formation fluid in HPHT gas well was recovered and characterized, and the phase state change characteristics of gas?liquid?solid three?phase fluid, wax precipitation mechanism and process were described accurately. Based on the phase equilibrium model, the wax location, fluid composition change and the influencing factors of wax deposition were analyzed. It was reasonable to explain that the mechanism of wax precipitation in HPHT gas well is the transient phase transition from gaseous to liquid and then to solid due to the rapid change of temperature and pressure, and the corresponding prevention and control strategies are put forward.

For the under?expansion jet generated after the failure leak of high?pressure pipeline, the Birch theory model was used to replace the actual pipeline leak hole with a pseudo?source. Under different conditions of Hydrogen Blend Ratio (HBR), leak hole size and pipeline running pressure, the concentration field distribution, explosion hazard boundary and explosion hazard range of hydrogen?doped natural gas pipelines after leakage and diffusion were studied. The results show that with the increase of HBR, the aggregation of HDNG after leak diffusion is reduced, the explosion hazard range is gradually decreased and the distal hazard is reduced. However, the increase of HBR shifts the position of explosion hazard boundary downward and increases the proximal hazard. With the increase of leak hole size and pipeline pressure, it will increase the influence area of HDNG after leak diffusion, which will move the explosion hazard boundary position upward and increase the explosion hazard range gradually and increase the distal hazard.

This paper proposed a method to improve the safety of shell and tube heat exchangers by adding a heat insulation layer at the inlet end of the heat exchange tube. Based on the SIMPLE algorithm, the transient change model of end temperature difference of three?dimensional shell and tube heat exchanger was established, and the effects of the changes of insulation thickness and insulation material on the safety of heat exchanger were compared. The results show that the temperature difference between the two sides of the heat exchange tube is significantly reduced when the pipe end insulation layer is installed, regardless of the material of the pipe end insulation layer; The greater the thickness of the insulation layer at the pipe end and the thermal conductivity of the insulation material, the greater the reduction of temperature difference, instantaneous thermal shock stress and temperature difference thermal stress on both sides of the heat exchange tube, and the higher the safety of the heat exchanger; When the thickness of the pipe end insulation layer is 247.5 mm and the thermal conductivity is 2.090 0 W/(m?K), the maximum instantaneous temperature difference on both sides of the heat exchange pipe can be reduced by 10.1%, the maximum temperature difference can be reduced by 12.5% during stable operation, and the instantaneous thermal shock stress and temperature difference thermal stress can be reduced by 10.1% and 12.5%.

The data acquisition and modeling of the depressed pipe were carried out using a 3D scanner, and the residual strength at the depressed pipe was evaluated; based on the modeling, the finite element analysis of the 3D modeled pipe containing the depression was carried out using ABAQUS software, and the stress?strain analysis was carried out using numerical simulation; the geometric deformation detection method was used to detect the depressed pipe, and the stress?strain at the depressed pipe was calculated and analyzed. The load?bearing capacity of the recessed pipe was evaluated; a comparative analysis was conducted for both cases of the pipe with/without internal pressure. The results show that the maximum Von Mises stress at the depression differs greatly between the two cases with/without internal pressure; in the case with internal pressure, the maximum Von Mises stress is located at the perimeter of the pipe depression rather than at the depression; in the case with internal pressure, the maximum equivalent force in the area near the depression is 22.6 MPa, while the maximum equivalent force in the case without internal pressure is 14.8 MPa. The maximum Von Mises stress applied to the pipe is distributed in the deepest part of the depression with a value of 710.3 MPa, and the maximum equivalent force becomes 8.99%, which is distributed in the inner part of the depressed pipe when the downward displacement constraint of 50 mm is set in the indenter. In engineering applications, the 3D scanning technology can be used to obtain the contour of the pipe depression more quickly, and the output data can be used to provide technical support for subsequent stress?strain analysis, pipe evaluation, and rehabilitation.

Aiming at the low efficiency of Apriori algorithm in scanning database and low dimensional frequent itemset, an efficient implementation method of Apriori algorithm was proposed, which is called EI_Apriori algorithm. This method utilizes the vector?based storage structure and pre?pruning to reduce the number of scanning databases and low?dimensional frequent itemsets and thus improves the efficiency of the Apriori algorithm. According to the actual situation of student achievement analysis, the constraints on the sequence relationship between courses are added in the association rule mining, and the constraints on the score level range are added in the association rules. The adjusted EI_Apriori algorithm was applied in score association analysis. The results show that the EI_Apriori algorithm can accurately find the association rules that meet the real needs, which proves the superiority of EI_Apriori algorithm.

Aero?engine usually contains a large number of pipes, the arrangement sequence of these pipes has a certain impact on the overall layout effect of the system. In order to reduce the degree of cross layout of multiple pipes, the evaluation method of pipe disassembly complexity was designed based on product assembly and disassembly, a Discrete Chicken Swarm Optimization (DCSO) algorithm was used to solve the pipe layout sequence planning. First, a calculation method of pipe disassembly complexity was proposed to evaluate the complexity of pipe system layout scheme. Next, the pipe was pre?planned by A* algorithm. Then, an obstacle avoidance algorithm was designed based on engineering rules to adjust the pipe. Finally, taking the pipe length and disassembly complexity as the optimization objectives, the pipe layout sequence was optimized based on DCSO, and the feasibility of the proposed method was verified by a layout example.

For a long time, researchers mostly analyze the transmission process of infected nodes in complex networks to get the target of forecasting and arresting the extend of the infectious diseases. In this article, the SEIR propagation dynamics model was extended to the undirected and powerless large small world network, and the weights between nodes were given as infection ability. Two initial node selection methods were selected to carry out multiple simulation experiments. Based on the traditional method of judging the impact of transmission by the number of infected people and infection threshold, the specific values of infection probability, peak value and inflection point time were added to analyze the impact of initial node selection on transmission process more comprehensively. The compared experimental results show that the initial node which the degree is larger and the betweenness is larger, the larger the propagation scale, the faster the propagation speed and the shorter the equilibrium time. This study provides some reference value for guard against and control of the extend of infectious diseases.

A waterborne polyacrylate colloid with hard core and soft shell structure was synthesized with methyl methacrylate (MMA), styrene (St), butyl acrylate (BA), methacrylic acid (MAA) as monomers, diacetone acrylamide (DAAM) as crosslinking monomer and adipic acid dihydrazide (ADH) as crosslinking agent. By adjusting the glass transition temperature (T_g), the emulsion can be self?forming film without adding film forming additive at room temperature. The influence of DAAM?ADH crosslinking system on the properties of latex films was investigated. DSC and TGA analysis showed that the T_g and thermal stability of crosslinked latex films are higher than those of uncrosslinked films. When the mass ratio of DAAM in core?shell is 1∶2, the comprehensive performance of latex films is better than that distributed in core or shell alone. With the increase of DAAM content, the water absorption decreased from 18.99% to 4.38%, and the Gel Fraction increased from 79.30% to 90.84%. When the molar ratio of ADH/DAAM is 1.25, the water absorption reaches the lowest and the Gel Fraction reaches the maximum.

This paper compared the variation trend of the output and consumption of diesel and the difference of the qualities of different sources diesel with the standard of Ⅵ diesel in China, and analyzed the composition, quality and problems of diesel pool in detail. It is considered that the most important problems in diesel quality upgrading process is how to reach the standard of diesel density and cetane number (including cetane index), rather than diesel sulfur content. Therefore, some countermeasures were put forward, such as identify the difference between cetane number and cetane index, optimizing crude oil processing, hydro?converting inferior diesel and adjusting the product structure of refinery.

Using corn straw as raw material of biochar and modified with chitosan and rare earth, chitosan?lanthanum chloride?biochar composites and chitosan?cerium chloride?biochar composites were prepared respectively. The structure and performance of CBC?La and CBC?Ce were analyzed by XRF, FT?IR and XRD. The adsorption properties of Cr(Ⅵ) in water under different adsorption conditions were investigated. The experimental results show that the Langmuir equation can simulate the isothermal adsorption behavior well, and the quasi?first?order kinetic equation has a higher fitting degree. The theoretical equilibrium adsorption capacity are 21.08 mg/g and 19.16 mg/g, which is close to the actual value. The desorption experiments show that CBC?La and CBC?Ce had the possibility of reuse. The adsorption mechanism mainly includes electrostatic adsorption, complexation and ion exchange. The experimental results show that the chitosan?rare earth?biochar composite material has a good application prospect in the removal of Cr(Ⅵ) from water.

The coking kerosene fraction was used as the raw material for the experiment. The linear α?olefins in the raw oil were enriched by complex extraction method, and the high viscosity poly α?olefin base oil (PAO) was synthesized by oligomerization. The effects of temperature, time and catalyst dosage on the properties of PAO were investigated. The kinematic viscosity, viscosity index and PAO yield rate at 100 ℃ were determined. Under the optimum process conditions of catalyst mass fraction of 6%, polymerization temperature of 25 °C, polymerization time of 8.0 h, addition polymerization temperature of 80 °C and addition polymerization time of 2.0 h, the reaction effect is the best: The kinematic viscosity of PAO at 100 ℃ is 43.54 mm²/s, the viscosit index is 163, the freezing point is -50 ℃, and the flash point is 291 ℃. The yield is 85.48%. Compared with the PAO40 standard, the obtained product is a high viscosity lube base oil.

Metal nanomaterials with high thermal conductivity are ideal promoters for enhanced gas hydrate formation, including metal?based nanoparticles, metal oxides, and metalloid oxides. In this paper, the effects of different kinds of metal nanomaterials on the formation of gas hydrates were reviewed, and the effects of parameters such as the induction time and gas consumption of enhanced hydrate formation were introduced from the three aspects of additive concentration, particle size and surface properties. The results show that the heat transfer effect of metal?based nanoparticles is better, and some metal oxides and metalloid oxides will exhibit an inhibitory effect; the appropriate addition concentration and particle size have an important impact on the formation of hydrates. In addition, the combination of metal nanomaterials and chemical reagents can significantly improve the dispersion stability of nanoparticles, thereby promoting the efficient generation of hydrates.

In this paper, a kind of composite phase change material (capric?lauric acid/expanded vermiculite) using expanded vermiculite as the matrix and capric?lauric acid binary eutectic as the adsorbent was fabricated by vacuum impregnation technology. The chemical compatibility, morphology, stability，thermal?physical properties and reliability of the prepared composite capric?lauric acid/expanded vermiculite were investigated by fourier transform infrared spectrum (FT?IR), scanning electronic microscope (SEM), thermal gravimetric analyzer (TGA), differential scanning calorimeter (DSC) and thermal cycling test. The melting and solidification phase transition temperatures of capric?lauric acid/expanded vermiculite are 18.42 ℃ and 17.51 ℃, respectively. The latent heat of melting and solidification phase transition are 66.9 J/g and 62.9 J/g, respectively. Besides, the encapsulation amount of capric?lauric acid in expanded vermiculite can reach 52.97%, and it has good thermal stability between working temperature. Moreover, the capric?lauric acid/expanded vermiculite was used to substitute for a certain proportion of fine sand to prepare thermal storage mortar, the mechanical and thermal performance of capric?lauric acid/expanded vermiculite?based mortar was evaluated. The test result shows that prepared capric?lauric acid/expanded vermiculite?based thermal storage mortar is a potential material for building heat regulation and energy saving.

The types of volcanic rock reservoir space, reservoir physical properties and the main controlling factors were systematically studied by the method of reservoir physical property experiment, core casting thin section observation and X?ray diffraction test. The results show that the Yingcheng formation volcanic rocks in the Dehui fault depression have strong alteration, and the reservoir space is dominated by dissolution pores and dissolution fractures. The average porosity of tuff and dacite are 12.40% and 7.47%, respectively, and the permeability is less than 1.000 mD, belonging to type Ⅲ reservoirs. Gas?bearing formations can be further identified based on acoustic and resistivity logging methods. Lithology and lithofacies are the main controlling factors for the development of reservoirs, and lithofacies models of extrusive facies, extrusive facies and explosive facies were established in combination with the characteristics of seismic reflections. It provides an important theoretical basis for clarifying the mechanism of volcanic rock formation and the distribution of reservoirs in the study area.