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.

In the multiphase flow pipeline transportation system， in the process of hydrate slurry flow， rugged terrain will be encountered. At this time， the use of inclined pipeline is particularly important. Therefore， the influence of the flow characteristics of gas hydrate slurry in the inclined pipe on the blocked pipeline was studied. The hydrate plugging experiment of oil + natural gas in oil?based system was carried out on the low?temperature and high?pressure visual hydrate experimental loop， and the effects of initial pressure， initial flow and other factors on the flow and plugging time of natural gas hydrate slurry were explored. At the same time， the micro changes of hydrate particles in the process of hydrate formation， flow and pipe plugging were analyzed by real?time online particle tester. The experimental results show that with the increase of initial pressure， the induction time， formation time and slurry flow time of natural gas hydrate are shortened， and the pipe plugging trend of natural gas hydrate increases. With the increase of initial flow rate， the induction time， formation time and slurry flow time of natural gas hydrate are prolonged， and the pipe plugging trend of natural gas hydrate is reduced. Finally， the process from hydrate formation to pipe plugging and the plugging mechanism were analyzed. The research results of gas hydrate plugging pipelines in oil?based systems show that the probability of gas hydrates blocking pipelines can be effectively reduced by reducing initial pressure and increasing initial flow rates in oil?based systems. The research results can provide theoretical reference and basis for maintaining and ensuring the safe flow of natural gas hydrate in pipelines.

With the development of artificial intelligence technology and big data Internet technology, the pipeline leak detection technology is developing in the direction of intelligence. Based on the classification of continuous pipeline leak detection technology and discontinuous pipeline leak detection technology, this paper introduced the principles of various leak detection methods, summarized and analyzed the research status of long?distance oil pipeline leak detection technology at home and abroad. The application of combined oil pipeline leak detection and location technology in long?distance oil pipeline detection was prospected.

Guaiacol (GUA) is extensively used as the model compound in catalytic studies of lignin, a most abundant renewable aromatic resource in nature. However, GUA is not easy to obtain good activity and selectivity in the hydrodeoxygenation reaction due to its complex structure with various reaction possibilities. So far, researchers have done great efforts to develop efficient catalysts and reaction processes for breakthroughs. This paper reviewed the research progress of transition metal catalysts and noble metal catalysts for hydrodeoxygenation of GUA, and discussed the reaction pathways and the factors which may affect the catalytic behavior, particularly focusing on their catalytic conversions of GUA to phenol or cyclohexanol through C_AR-O bond cleavages and aromatic ring saturation. A prospect regarding the future research directions on the catalyst improvement and reaction process optimization were also presented.

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.

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 proposes a model?free control protocol design method based on off?policy reinforcement learning for solving the optimal consensus problem of heterogeneous multi?agent systems with leaders. The dynamic expression of local neighborhood error is complicated for the heterogeneous multi?agent systems because of its different system state matrices. Compared with the existing solution of designing observer for distributed control of multi?agent system, the method of solving global neighborhood error state expression proposed in this paper reduces the complexity of calculation. Firstly, the dynamic expression of global neighborhood error of multi?agent system constructed from augmented variables is established. Secondly, the coupled Bellman equation and HJB equation are obtained through the value function of quadratic form. Then, the Nash equilibrium solution of the multi?agent optimal consensus is obtained by solving the optimal solution of the coupled HJB equation, and the Nash equilibrium proof is given. Thirdly, an off?policy Q?learning algorithm is proposed to learn the Nash equilibrium solution of the multi?agent optimal consensus. Then, the proposed algorithm is implemented by using the critic neural network structure and gradient descent method. Finally, a simulation example is given to verify the effectiveness of the proposed algorithm.

With the increasing complexity of networked power systems, traditional control schemes are difficult to meet the actual needs. Bandwidth constraints, network security and actuator saturation have become important factors affecting the stability of power systems. An improved event trigger mechanism was introduced to improve the utilization rate of bandwidth resources for the problem of bandwidth resource limitation, and a new mathematical model of power system under deception attack and actuator saturation was constructed. Based on this number model, the sufficient conditions for the asymptotic stability of the power system were obtained by Lyapunov theory, and the design scheme of the security controller was given by using linear matrix inequality technique. Finally, an example of power system was given to illustrate the effectiveness of the proposed scheme.

HP?MOF?74(Mg _x Ni_1-x ) (x=0.25, 0.50, 0.75) was synthesized by solvothermal method with Mg and Ni as central metals and sodium dodecylbenzene sulfonate (SDBS) as template. Using flue gas CO₂ and N₂ as adsorbents, the performance of HP?MOF?74(Mg _x Ni_1-x ) in adsorption and separation of CO₂/N₂ at 273 K and 298 K was investigated, the isotherms of CO₂ and N₂ on three different HP?MOF?74(Mg _x Ni_1-x ) materials were measured at 273 K and 298 K by static volumetric method, and the experimental data sets were fitted by Dual Site Langmuir Freundlich (DSLF) and Single Site Langmuir Freundlich (SSLF) models. The adsorption selectivity of CO₂/N₂ binary mixture was estimated according to the Ideal Adsorption Solution Theory (IAST). In addition, the isosteric heat of adsorption (Q_st) was calculated using the Clausius Clapeyron equation. The results show that the CO₂ adsorption capacity of HP?MOF?74(Mg_0.50Ni_0.50) sample is 4.864 mmol/g at 273 K and 100 kPa; the adsorption isotherms of CO₂ and N₂ on HP?MOF?74(Mg _x Ni_1-x ) are in good agreement with Dual Site Langmuir Freundlich (DSLF) and Single Site Langmuir Freundlich (SSLF) models respectively, indicating that the adsorption behavior of CO₂ is double sites adsorption, while the adsorption behavior of N₂ is single site adsorption; at 273 K and 100 kPa, the IAST adsorption selectivity of HP?MOF?74(Mg_0.25Ni_0.75) for CO₂ is 2 263, and the adsorption capacity and selectivity are better than those of traditional adsorbent MOF?74; the CO₂ isosteric heat of adsorption on HP?MOF?74(Mg _x Ni_1-x ) is higher than that of N₂, indicating that the surface free binding energy of CO₂ on HP?MOF?74(Mg _x Ni_1-x ) is higher.

Electrospinning is a fiber manufacturing process in which polymers are drawn and spun under the action of a high?voltage electrostatic field. This method has been widely used in material chemistry due to the simple preparation, low cost as well as easily available of micro?nano?scale fibers. In this paper, a polysulfur high?nucleus caged compound (Co₄₈) constructed by thiacalixarene was used as the loading material, and polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) blend (PAN/PMMA) was used as the spinning support, Co₉S₈ nanoparticles loaded carbon nanofibers (Co₉S₈@CNFs) were prepared by electrospinning technique. Composite nanofibers were prepared by spinning carriers with PAN and PMMA mass ratios of 10∶0, 7∶3 and 5∶5, respectively, and the carbon nanofiber composites obtained after heat treatment were used as electrode materials for the study of lithium?ion battery materials. The addition of PAN and PMMA has a positive effect on the electrochemistry of the final product compared to the calcined product of Co₄₈ crystals. The composites fabricated from PAN and PMMA presented high specific capacity，good cycling stability and rate capability.

The finite element model of the bolt flange washer was established, and the fastening experiment of the DN500 bolt flange connection system was carried out to verify the rationality of the finite element model. By controlling the width of the nut washer and the medium pressure of the pipeline, the effect of adding the nut washer on the stress distribution on the washer and bolt was compared and analyzed. It was found that adding a reasonable sized nut washer can not only increase the contact area between the nut and the flange surface and increase the compressive stress on the gasket, but also in the case of high bolt pre?tightening load and medium pressure. Prevent the bending deformation of the bolts and the pressure failure of the washers, increase the service life of the bolts, and improve the overall sealing performance of the bolt flange connection system.

Aiming at the problem that the existing online life prediction of lithium?ion batteries based on the correlation vector machine has a single consideration factor, which results in unsatisfactory prediction accuracy, a method based on principal component analysis (PCA) for weighted construction of characteristic factor variables was proposed. In this method, a variety of characteristic factor variables are taken as the research object to find the matrix of the score vector after the linear transformation. The feature coverage degree of different score vectors to the original variable data matrix is analyzed, and the corresponding feature vectors are constructed by weighted fusion. Using the vector as input, a prediction model is established by the relevance vector machine and the online prediction of lithium?ion battery life is performed, and the prediction results are finally obtained. International public battery data was used as the research object, and MATLAB experiments were used to verify that the method has the feasibility of multivariate prediction of battery life, and the prediction effect is better.

To investigate the structure?function relationship of novel extended surfactants and the mechanisms of reducing interfacial tensions (IFTs) at oil?water interface, the interfacial tension values of 13?P series 13?P（I?C₁₃（PO） _x S,x=5,10,15,20）with different concentrations of NaCl and n?hexane to n?tetradecane at fixed concentration were measured by rotary drop interfacial tension meter. The result indicates that at higher numbers of PO（x=15,20), the n_min values become higher with increasing concentration of NaCl. At lower numbers of PO（x=5,10), the n_min values become lower with increasing concentration of NaCl. It reflects two mechanisms on reducing IFTs: Hydrophilic lipophilic equilibrium effect and hydrophilic hydrophobic group in size matching effect, both of which work together, and the size matching plays a crucial role at lower numbers of PO and HLB dominates at higher numbers of PO.

Taking advantage of its high?speed and high?precision characteristics, cooperative robots can improve production efficiency by imitating human creative and complex actions. At present, the simulation of human action mainly comes from the long?term debugging of the deployment personnel, which is lack of general solutions and can′t be deployed quickly. Based on this, an anchor?free RepVGG network?based Siamese network collaborative robot target tracking algorithm was proposed. The algorithm consists of a siamese network module, a classification regression module and a robot execution module. The siamese network module used the improved RepVGG network instead of ResNet as the backbone network to extract image features, which can improve the running speed of the whole network without losing accuracy，reduce the hardware requirements and is more friendly to special deep learning chips; the classification and regression module introduced the centrality branch to improve the prediction accuracy of the center point of the tracking frame; the robot execution module uses scale penalty and aspect ratio penalty to smooth the tracking boxes and ensure the smooth operation of the collaborative robots. Experimental results show that the average rate is 14 FPS higher than that before replacing the backbone network, which realizes real?time object tracking.

The cold flow property of biodiesel can be effectively improved by pour point depressants (PPD). The terpolymer (AHM) was prepared by solution polymerization of hexadecyl methacrylate, hydroxyethyl methacrylate and maleic anhydride. The effect of AHM on pour point reduction of biodiesel was also investigated. The hexadecyl methacrylate and AHM were characterized by infrared spectroscopy. The optimal reaction conditions of AHM were determined by single factor experiment: n(hexadecyl methacrylate)/n(hydroxyethyl methacrylate)/n(maleic anhydride)=2∶1∶2, the initiator mass fraction is 3.0%, the solvent mass fraction is 65%, the reaction time is 3 h, and the reaction temperature is 85 ℃. When the mass fraction of AHM is 0.7%, the freezing point of biodiesel decreased by 12 ℃. The morphology of wax crystals precipitated from biodiesel at low temperature after adding pour point depressant was observed by polarizing microscope, and the morphology was more uniform and dense.

In view of the current situation that independent automobile brands are big but not strong in the domestic market, this paper took Chinese independent automobile brands as the research object, analyzed the consumption psychology of Chinese consumers, and discusseed the influence of brand cognition, customer experience, perceived novelty, perceived practicality and friends' recommendation on brand advocacy, and with customer purchase intention as the mediating variable, the structural equation theory was used to construct, test and revise the model, and the hypothesis test was carried out. The results show that customer experience, perceived novelty and friends' recommendation can directly promote customers' purchase intention and brand advocacy, while perceived practicality can indirectly promote brand advocacy, while brand cognition can only directly promote brand advocacy. Purchase intention plays a mediating role among customer experience, perceived novelty, perceived practicality, friends' recommendation and brand advocacy,but does not play an intermediary role between brand cognition and brand advocacy..

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.

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.

A novel distributed model predictive control (DMPC) approach based on immune algorithm (IA) to find out the optimal system decomposition structure is proposed. The IA is used to solve decomposition problems for input clustering decomposition (ICD) and input?output pairing decomposition (IOPD), which can minimize the impact of input?output coupling between systems, and then DMPC algorithm is used to control the decomposed system. This approach effectively reduces the coupling between subsystems, and reduces the communication load of the system. Finally, a heavy oil fractionation chemical process is simulated and compared with the centralized MPC simulation results to verify the effectiveness of the algorithm.

In this work, the inner and outer loop control strategy is adopted for the unmanned aerial vehicles (UAVs) formation system. Firstly, a sliding mode control method based on memory event?triggered mechanism (METM) is proposed for the position subsystem under delay and disturbance. The second?order model is established for each UAV, and the leader?follower framework is adopted to realize the desired flight formation. Secondly, an adaptive METM is proposed to alleviate the transmission burden, in which control input feedback is introduced. For the resulting communication delay of the control input in the proposed METM and the external disturbance to the system, a sliding mode controller is designed, which maintains desirable control performance and solves the influence of communication delay and bounded disturbance to a certain extent. Thirdly, the stability of the closed?loop system is proved by applying Lyapunov theory and H_∞ control theory, and a method that facilitates solving controller gain and triggering parameter through a series of linear matrix inequalities (LMIs) is proposed. Moreover, based on the obtained virtual control quantity, a tracking controller is designed for the attitude subsystem. Finally, a simulated example is exploited to verify the effectiveness of the proposed method.

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.

In order to improve the balance between invisibility and robustness of image watermarking, a color image watermarking algorithm is studied by using wavelet transform and Heisenberg array decomposition （HAD） singular value decomposition （SVD）. Firstly, the host image and watermark image are transformed through color space color space, then the host image is transformed by wavelet transform, then the low frequency coefficients are decomposed by HAD and SVD, and the watermark is embedded after SVD in the low frequency. The experimental results show that the proposed watermarking method has strong robustness against multiple watermarking attacks, which is reflected by the normalized correlation NC of the objective evaluation criteria of extracted watermarks. The host image has good invisibility after embedded watermark, which is reflected by objective evaluation standard peak signal?to?noise ratio （PSNR） and structural similarity of images （SSIM）. It can embed grayscale or color large watermark with strong ability of embedding information. It is concluded that that the watermarking method has a certain application value.

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.

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.

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.

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.

Ozone is a clean and strong oxidant, which has been widely used in the degrading of organic pollutants. However, the ozone oxidation process alone is not ideal for the treatment of difficult?to?degrade organic pollutants in water. Therefore, ozone catalytic oxidation technology came into being, and the selection of catalyst is the key factor to determine its degradation effect. Based on the various types of catalysts, the mechanism of metal oxides, carbon?based materials and supported composite catalysts for the catalytic oxidation treatment of water pollutants by ozone was reviewed. The existing problems and the main problems that need to be solved at present were analyzed to provide theoretical basis and reference for the research and development of suitable catalysts.

In this work, the HTO (H_4x/3Ti_2-x/3□ _x/3O₄·nH₂O) was used as the precursor raw material, and the nanoscale titanium oxide particles (ST01) were loaded on the surface of the HTO by water bath impregnation, and the TiO₂ homogeneous structure composite was topologically synthesized by calcination method. Using X?ray diffraction （XRD）, Raman spectroscopy (Raman) and other testing methods, the effect of calcination temperature on the phase transition process with titanium dioxide was studied in detail. The results indicate that the HTO can transfer to TiO₂（B）, anatase TiO₂ and rutile TiO₂ with increased temperatures, and the TiO₂ homophase composites are obtained with various structure and content of TiO₂. The degradation experiment was carried out with Rhodamine B （RhB） as the pollutant model. The photocatalytic activity of the sample at 600 ℃ is significantly higher than that of other samples, mainly because the separation efficiency of electrons and holes of the sample is the highest at this time, indicating that the structure and composition of homogeneous composite TiO₂ affect its photocatalytic activity. In addition, dye?sensitized solar cell （DSSCs） experiments show that the reason for the higher optoelectronic performance of the samples at 600 ℃ is that the two?dimensional sheet?like morphology facilitates the rapid migration of photogenerated carriers.

Nickel?based superalloys, as typical difficult?to?machine materials, are widely used in aerospace engines, chemicals, ships, and other fields. To meet the special working conditions requirements of the aero?engines, and further improve the surface machining quality and processing efficiency, relevant researchers have carried out many theoretical studies and process explorations. The development of nickel?based single crystal superalloys and polycrystalline superalloys, and their material properties were firstly reviewed. Then the main research results of domestic and overseas scholars on the grinding removal mechanism, grinding surface integrity, and process characteristics of nickel?based superalloys were summarized, and their development trends are prospected.

OA?ZnCl₂/SG supported catalyst was synthesized by sol?gel process using octanoic acid?zinc chloride deep eutectic solvents (OA?ZnCl₂ DESs) as additive. The structure of the catalyst was analyzed by infrared spectroscopy, X?ray diffraction, N₂ adsorption?desorption and scanning electron microscopy. The performance of oxidative desulfurization was studied by using OA?ZnCl₂/SG as adsorbent and catalyst, and hydrogen peroxide as oxidant. The loading dose of DESs, reaction temperature, n(H₂O₂)/n(S) ratio, the amount of catalyst and the effect of different sulfides on desulfurization rate were investigated. The results show that the desulfurization rate of the catalyst reaches 95.6% under the optimal conditions, and after 5 cycles, the desulfurization rate drops to 89.7%.

Chemical wax inhibitors are widely used in the field of waxy crude oil extraction and transportation, providing an important guarantee for the safe and efficient operation of the waxy crude oil extraction and transportation process. At present, many basic experimental studies and numerical simulation studies on chemical wax removal have been carried out to explore the types, mechanism of action and application scope of chemical wax inhibitors. Common chemical wax inhibitors mainly include fused?ring aromatic hydrocarbon type wax inhibitors, surfactant type wax inhibitors, high molecular polymer pour point depressant type wax inhibitors and new nano?particle wax inhibitors. They usually prevent the association and deposition of wax crystals by water film theory or wax crystal modification theory. Among them, fused?ring aromatic hydrocarbon wax inhibitors, surfactant wax inhibitors, and polymer pour point depressant wax inhibitors have disadvantages such as poor environmental friendliness, poor environmental adaptability or poor economy. The focus of future research should be to explore green, efficient and general?purpose chemical paraffin inhibitors, use nanoparticles to improve the performance of paraffin inhibitors, and continue to explore more environmentally friendly chemical paraffin inhibitors.

Oily sludge has been classified as hazardous waste because of its complex composition， high stability and difficult treatment. At present， the treatment technologies of oily sludge include landfill， solvent extraction， thermochemical cleaning， ultrasonic assisted treatment and biological treatment. Among them， the thermochemical cleaning technology has the advantages of easy operation and high reliability， and the key technology lies in the selection of cleaning agent. Different types of single cleaning agents are introduced， including inorganic sal cleaning agents， chemical surfactants and biological surfactants. This paper classifies and summarizes the compound of different types of single cleaning agents， and focuses on the mechanism of the compound of non?ion?anionic surfactant， non?ion?non?ionic surfactant， alkaline inorganic salt?surfactant and biological surfactant. Based on this， the development direction of thermochemical cleaning agent is prospected in order to improve the cleaning effect of oily sludge.

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.

In recent years, the rapid expansion of industries such as new energy has significantly heightened the demand for lithium resources. China boasts ample lithium reserves; however, 80% of these reserves are concentrated in salt lake brine, and the high magnesium?to?lithium ratio inherent in salt lakes poses challenges for lithium extraction. To ensure a stable supply of lithium resources in our country, it is imperative to develop cost?effective and highly efficient technologies for lithium extraction from salt lakes. Recent studies have demonstrated that the combination of emerging membrane separation technology with traditional processes holds great potential for achieving significant advancements in lithium extraction from salt lakes. This review aims to present the latest membrane technologies for extracting lithium from salt lake brine. It comprehensively discusses cutting?edge research findings from various perspectives, including the pore structure of membrane, precise design of the chemical environment within the pores, development of innovative membrane fabrication processes, and the integration of multiple membrane processes. By doing so, the review offers valuable insights and guidance for the design of new membrane materials. Furthermore, the review provides a comprehensive overview of the current bottlenecks faced by membrane separation technology in the process of lithium extraction from salt lakes. It also explores the potential prospects of biomimetic membrane materials.

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%.

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.

In the process of oil well operation, wireless communication technology can solve the problems such as high bit error rate and poor real?time performance in the down?hole parameter transmission. How to choose the characteristic frequency of sound wave and explore the attenuation degree of sound wave in the oil string have become the research hotspots in recent years. In this paper, the attenuation characteristics of acoustic signals transmitted along metal tube walls were studied, a communication model was established, and the attenuation law of acoustic signals was quantified on this basis. Combined with Comsol waveform simulation software, the correctness of communication theory model and characteristic frequency selection was verified. The results show that this method can effectively transmit acoustic signals and provide an optimal frequency selection scheme for oil well remote wireless communication technology.

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.

The wet gas gathering pipelines will produce natural gas hydrate with the condition of high pressure and low temperature, which may cause blockage of pipelines or failure of key control equipment. Adding alcohols Thermodynamic?Inhibitor(THI) is one of the feasible proposals to prevent hydrate formation. If the amount of THI is poured excessive, the costs of procurement, transportation, storage and water treatment will increase in large quantities. Therefore, it is significant to determine the minimum dosage of THI based on a reasonable safety margin. Calculation of THI injection dosage based on empirical formula method and phase equilibrium software, without considering the effect of flow. In this paper, a method coupling of phase equilibrium and flow was used to optimize the injection dosage of THI. Based on the OLGA component tracking model, the temperature, pressure and THI concentration along the line are tracked, and then the THI dosage was predicted more accurately. Taking the gas gathering pipeline of land and submarine as an example, different calculation methods were compared. The results show that the new method can reduce the THI consumption by more than 10%.

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%.

Due to the high storage capacity and multiple electron?transfer chemistry of sulfur (S), Li?S battery with virtues of high theoretical capacity/energy density, eco?friendliness and abundant supply has been considered as one of the most promising candidates for next?generation battery systems. The capacity of Li?S battery is much higher than that of traditional metal oxide cathode?based lithium?ion battery, which is regarded as the highest capacity of solid?state cathode?materials at current stage. As a vital component of Li?S battery, separator plays a profound role in resolving crucial issues (e.g., shuttling effect, volume expansion, poor conductivity and metal dendrites, etc.) of Li?S battery. So far, some pioneering works have been reported in the exploration of separators for Li?S battery. On this basis, covalent organic frameworks (COFs), possessing the advantages of low density, high porosity, well?defined structure, designable structure and functions, is a kind of potential materials for the functional modification of Li?S battery separators. This review will summarize the reported works about COFs in Li?S battery separators including their structural characteristics, preparation?methods, application forms and battery properties. It will also provide a brief perspective for the applications of COFs in Li?S battery separators and hope that it might give new insights for scientists in related fields.

Template agent is an essential part in the synthesis of molecular sieves, which has great influence on the physical properties and catalytic properties of molecular sieves. SAPO?34 molecular sieve was synthesized by hydrothermal method using stainless steel tube as crystallization vessel. The effect of PEG?800 addition on crystallinity, morphology and acidity of molecular sieve was investigated, and its MTO catalytic performance was evaluated. The results show that the molecular sieve samples synthesized with TEAOH & PEG?800 as the composite template agent are thin plate?like, the crystallinity and acidity are suitable, and the longest catalytic life is 340 min. When the methanol conversion is above 95%, the selectivity of diolefins is up to 84.0%. It is also found that the thinner the crystal thickness of the lamellar molecular sieve, the better the catalytic performance.

As the main weighting agent of oil?based drilling fluids, barite has many problems with high?density oil?based drilling fluids. In order to explore the applicability of micro?manganese mineral powder in oil?based drilling fluids. The particle size distribution and microscopic morphology of barite and micro?manganese ore powder were analyzed by laser particle size analyzer and scanning electron microscope. The differences in rheology, water loss and wall?building, lubricity, settlement stability, and reservoir protection performance between barytic petroleum?based drilling fluid system and micromanganese slag oil?based drilling fluid system were studied. The results show that under the condition of low density, the difference between the micromanganese ore powder system and the barite system is small; under high density conditions, the micro?manganese ore powder system has low viscosity and high cutting, the viscosity coefficient of the mud cake is less than 0.10, the sedimentation density difference is less than 0.03 g/cm³, and the permeability recovery rate after acid dissolution is higher than 95.00%. Its rheology, lubricity, sedimentation stability, and reservoir protection performance are better than the barite system, but compared with the barite system, the micro?manganese ore powder system has a large water loss and poor mud cake quality. It is recommended to compound the micro?manganese ore powder with a weight Spar to improve the water loss of the system. The research results fully reveal the difference in performance between the micro?manganese mineral powder oil?based drilling fluid system and the heavy crystal oil?based drilling fluid system, and provide support for the micro?manganese mineral powder to improve the performance of high?density oil?based drilling fluids, and also increase the weight of high?density oil?based drilling fluids. It also provides a new development direction for the application of ultra?high density oil?based drilling fluid weighting agents.

In order to improve the fastening effect of the bolt flange of pressure vessel, the structure of the hydraulic wrench and the holding sleeve was improved, and the holding sleeve was optimized, and a new type of fixed wrench was designed. The paper introduced and compared the joint use of hydraulic wrench and holding sleeve in bolt flange fastening operation, improved the structure of the holding sleeve, and analyzed the static structure of the new type fixed wrench by ANSYS. The results show that the structure optimization can effectively improve the fastening effect of flange bolts of pressure vessel.

Ferric nitrate was used to provide iron source, and Fe?C₃N₄ composite material was prepared by impregnation method. FT?IR was used to characterize and analyze the prepared materials. The results show that Fe doping does not change the skeleton structure of g?C₃N₄ and can increase the photocatalytic performance of g?C₃N₄ materials. Taking orange II as the target pollutant, Fe?C₃N₄ catalyzed the activation of persulfate to degrade azo dyes under visible light. The effects of persulfate dosage, Fe?C₃N₄ dosage, pollutant concentration and pH conditions on the degradation effect were examined, and the reaction kinetics was studied to analyze the stability of the prepared catalytic materials. The results show that when the Fe?C₃N₄ concentration is 2.0 g/L, the molar ratio of persulfate to pollutants is 1 200∶1, and pH=3, the degradation effect is best, and the degradation rate is 77.8%; Fe?C₃N₄/persulfate system is dual the degradation of nitrogen dyes satisfies the quasi?second?order kinetic equation; Fe?C₃N₄ material is reusable.

Sinopec Dalian Research Institute of Petroleum and Petrochemicals developed the "low temperature diesel absorption" VOCs treatment device for an aromatics and styrene tank farm. However, the waste gas volume sucked into the liquid ring compressor is always unstable. In this paper, a new automatic bleed gas volume control scheme of liquid ring compressor was adopted, the optimal control parameters were obtained by designing the bleed air control scheme for the compressor motor frequency and the opening of the return valve of the liquid ring compressor according to the pressure on the pipeline connected to the tank area. The results show that this technology can meet the requirements of energy saving and consumption reduction while ensuring that the exhaust gas is discharged up to the standard, and take into account the long?term stable operation of the equipment.

In order to explore the best extraction technology of flavonoids from Maoyanberry tea, the extraction conditions of flavonoids from Maoyanberry tea were optimized by using the method of single factor and response surface. The results showed that the optimal extraction conditions were as follows: Ethanol volume fraction 80%, liquid?solid ratio 25 mL/g, water bath temperature 85 ℃, water bath time 40 min. Under these conditions, the yield of flavonoids was 162.72 mg/g, which was close to the predicted value of the model, indicating that the optimized method was reasonable and feasible.

Based on the limitation of the eccentric twin screw extruder's own structure, a new type of eccentric three screw extruder was designed. Polyflow software was used to analyze the pressure field, shree velocity field, velocity vector field, mixing index, separation scale, average mixing efficiency, logarithmic stretching and other parameters. The flow and mixing mechanism of the eccentric tri?screw extruder were studied and compared with that of the eccentric twin?screw extruder. The results show that under the same conditions, the stretching and folding effect of the eccentric three?screw extruder is better, and the mixing efficiency is higher than that of the eccentric twin?screw extruder, which provides a theoretical basis for further exploring the chaotic mixing mechanism and optimizing the eccentric multi?screw extruder.

Due to the complex submarine environment, submarine pipeline steel often faces serious corrosion risk. Through potentiodynamic polarization technology and AC impedance technology, the effects of hydrostatic pressure, mass concentration of dissolved oxygen and growth days of sulfate reducing bacteria (SRB) on the electrochemical corrosion behavior of X70 pipeline steel in simulated solution in the South China Sea were investigated. Combined with electron microscope characterization technology, the corrosion morphology was analyzed, and the mechanism of the corrosion behavior of X70 steel under the coexistence of three environmental factors was clarified. The results show that the self corrosion current density of X70 pipeline steel in the experimental environment inoculated with SRB is twice that of sterile steel; under the pressure of 0~3.5 MPa, the corrosion degree first intensifies and then slows down; when SRB and dissolved oxygen coexist, the presence of oxygen inhibits the number of facultative anaerobic bacteria SRB, thus inhibiting corrosion.

The double resonance Raman (DRR) peaks of Janus MoSSe monolayer are important fingerprints of material characteristics. However, the origin of DRR peaks is still poorly understood and needs urgent clarification. Based on density functional theory, high?order quantum perturbation theory and group theory analysis, the DRR spectra of Janus MoSSe monolayer were studied theoretically and systematically. It is found that the inverse lattice wave vector of the electro?optical resonance coupling process of Janus MoSSe monolayer depends on the laser energy, and any wave vector may appear in the first Brillouin zone. Based on group theory analysis, the symmetry conditions for the generation of DRR activity were deduced, and the fundamental reason for the occurrence of a large number of DRR peaks in the Janus structural system was elucidated. This study provides theoretical guidance for understanding the DRR processes occurring in two?dimensional Janus structural system, and provides a rational theoretical means for clarifying the origin of the DRR peaks.