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.

C ₉ petroleum resins was obtained by two-step synthesis from C ₉ fraction, which is the side product from enthylene production in the boiling range of 140～196 ℃. The processes of free radical polymerization and catalytic polymerization by Lewis acid were well investigated, and the effect of polymerization method, reaction time and reaction temperature on product quality was discussed. The results show that C ₉ petroleum resins can be obtained with light color and higher yield under the following conditions: the mass fraction of initiator 0.01%, the mass fraction of catalyst 1.50%, reaction time 4.5 h, free radical polymerization time 1.5 h, catalytic polymerization time 3.0 h and reaction temperature 55 ℃.

With the rapid development of human?computer interaction, electronic skin, wearable electronics and other emerging fields, flexible strain sensing materials as one of the core components have become the hot spot of the current research. The conductive polymer composites composed of conductive material and flexible polymer have the advantages of good flexibility, light weight, easy processing and forming, and the conductive property of the material changes under strain stimulus, so it can be used as flexible strain sensing material. This paper reviewed the classification and characteristics of flexible strain sensing materials based on conductive polymer composites, introduced the strain response mechanism of different sensing materials in detail, and summarized the factors that affect the strain sensing performance of conductive polymer composites.

In this paper, the heat treatment process of carburizing and quenching of 20CrMnTi steel gear was simulated by DEFORM?HT software, and the carbon mass fraction change from the surface layer to the core after carburization was obtained. The changes in the martensite structure after quenching were analyzed, the residual stress after quenching was analyzed, the appropriate quenching cooling medium was selected, and the metallographic structure and the Rockwell hardness from the surface to the core were measured through experiments. The results show that the metallographic structure and Rockwell hardness are in good agreement with the simulation results, which have certain guiding significance for production.

Titanium sulfate was used as a raw material, and a titanium oxide (TiO₂) was prepared by direct high?temperature calcination in a muffle furnace. FT?IR, XRD, UV?Vis, SEM were used to characterize the structure of the catalyst. The results show that the direct calcination method can prepare anatase titanium dioxide and apply it to the oxidative desulfurization of dibenzothiophene. Using acetonitrile as the extractant and titanium oxide as the catalyst, the oxidation method was used to remove dibenzothiophene from the simulated oil. The effects of catalyst dosage, reaction temperature, n(H₂O₂)/n(S), and different sulfur compounds on the desulfurization effect were investigated, and the recycling performance of the catalyst was also investigated. Under the optimal desulfurization conditions, the desulfurization rates of dibenzothiophene, 4,6?dimethyldibenzothiophene, benzothiophene, and mixed diesel are 99.5%, 35.6%, 65.0%, and 53.4%. After the catalyst was recycled five times, the catalytic desulfurization effect was still as high as 90.3%.

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.

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.

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.

Chiral oxazolines are a type of important chiral heterocycles compound, which are not only present in many biologically active natural products and drug small molecules with physiological activity, but also in chiral cofactors and chiral ligands often used in chiral synthesis. Currently, the asymmetric synthesis of chiral oxazolines still relies on the condensation between chiral amino alcohols and carboxylic acid derivatives. However, due to the limited availability of chiral amino alcohols and the tedious synthetic route, the development of highly efficient and straightforward methods for chiral oxazolines synthesis via asymmetric catalysis is of significant synthetic value. In this paper, we have summarized the recent advances in the asymmetric catalytic synthesis of chiral oxazoline derivatives through transition metal catalysis and organocatalysis, including asymmetric Aldol reactions, asymmetric clizations and others.

The geometric model of a certain oil and gas mixed transportation pipeline was established with OLGA software, and the transient flow law during the pipeline shutdown and restart process was studied. First, the distribution characteristics of temperature, pressure and liquid holdup along the pipeline during steady state operation were analyzed, and the location of the minimum temperature and the location of the maximum pressure along the pipeline were determined. The influence of environmental temperature and shutdown time on operating parameters were analyzed. The safe shutdown time when the minimum temperature temperature is higher than its freezing point was determined. In the actual operation process, the shutdown time should not exceed the safe shutdown time, otherwise problems such as pipeline condensation and excessive starting pressure will easily occur, which threaten the safety of the pipeline.

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.

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.

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.

Paraffin emulsion was prepared from liquid paraffin by the means of adding coemulsifier. The effects of the emulsifie species and their dosages, water dosage, emulsifying temperature, and emulsifying time on the paraffin emulsion properties were studied. The results showed that composite emulsifiers could provide better performance for the paraffin emulsion. The influencing factors can be arranged in order：water dosage>emulsifier dosage>emulsifying temperature>emulsifying time. Stable paraffin emulsion can be prepared under the optimum conditions：m(glycerol monostearate)/m(Tween80)=3∶4, emulsifier dosage 0.9％，emulsifying temperature 85 ℃，emulsifying time 50 min，water dosage 62.0％ and stirring speed 1 100 r/min. The experimental result indicated that the liquid paraffinemulsion had better stability density and dispersibility.

As the greenhouse effect becomes gradually significant, CO₂ capture and storage (CCS) has turned into a potential emission reduction measure, and the adsorption method of CO₂ capture is one of the most promising technologies. Porous solid adsorbents have attracted widespread attention due to their excellent CO₂ adsorption performance. This review focused on the research of CO₂ removal by adsorption. Five different adsorption materials were introduced, and the main factors affecting CO₂ adsorption were summarized, as well as the adsorption performance of modified materials. The results show that the changes of temperature, pressure, and pore structure can affect the physical adsorption properties of the materials; reduction, oxidation, and metal ion loading modification can improve the CO₂ adsorption performance by Changing the type or number of functional groups on the surface of the material.

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.

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.

As a new type of clean, carbon?free, sustainable and efficient energy source, hydrogen has great potential in the future energy mix. Hydrogen purification by pressure swing adsorption is the main separation technology for hydrogen production with high purity, low energy consumption and high degree of automation. In this paper the progress in research and application of pressure swing adsorption hydrogen production in theoretical simulation, process control optimization and adsorbent materials were critically reviewed, and the future development of pressure swing adsorption hydrogen production technology was prospected.

As an important semiconductor photocatalytic material, bismuth oxide (Bi₂O₃) is considered as a promising visible photocatalyst due to its special electronic structure and excellent visible light response performance. It displays a good application prospect in photocatalytic treatment of wastewater. However, the application of Bi₂O₃ is limited by its low photocatalytic performance, therefore, Bi₂O₃ pholocatalyst with superior performance is expected to be obtained by modifying methods by the researchers. In this review, a series of modification methods, such as surface morphology regulation, surface modification, metal ion modification and semiconductor combination, are summarized. Then, the future development of modified Bi₂O₃ photocatalytic materials is prospected.

In recent years, with the continuous development of nanotechnology and oilfield development technology, nanomaterials have been widely used in water shutoff and profile control agents and have achieved varying degrees of development. This article reviews the research progress and latest achievements of nanomaterials in water shutoff and profile control from four aspects: foam, polymer gel, emulsion, and superfine cement slurry, and analyzes the use of nanomaterials in water shutoff and profile control agents. The mechanism of action and its influence on the law. It is found that after adding nanomaterials to the system, it can interact with the water shutoff profile control agent by its physical and chemical properties such as small size and large surface area so that the stability, strength, and strength of the water shutoff agent can be improved. The temperature and salt resistance is significantly improved, thereby effectively improving the water shutoff rate and oilfield recovery rate. In addition, from the perspective of water shutoff agent research and development, various problems in current research in this area are pointed out, to provide a reference for the research and application of nanomaterials in water shutoff profile control agents.

For a long time, fabric defect detection has been completed by quality inspectors. Meanwhile, the process of defect discrimination is greatly affected by subjective factors and has the problems of low detection efficiency and high cost. With the close combination of computer vision technology and various fields, fabric defect detection system based on vision has gradually become an important solution to replace manual quality inspection. For the fabric defect detection based on vision, this paper reviews the aspects including industry development, general detection standards, overall structure of the system and key technologies in detection algorithms, introduces the existing fabric defect detection products based on vision in the market, analyzes the common defect detection standards and the basic structure of the detection system, and summarizes and compares the research status of image processing and deep learning technology in the field of fabric defect detection in recent years. Finally, the paper summarizes the key problems to be solved, and discusses the possible development direction in the future.

The ferrocene shows definite aromatic and redox properties, which can used as a switch model substance. In alcohol solution of lithium perchlorate, the redox reaction process of ferrocene is quasi-reversible, in which the electron transfer number determined is 1, and the diffusion coefficients of ferrocene ion (Fc+) and Fc are 2.24×10-3 cm2/s and 4.34×10-3 cm2/s, i.e. the diffusion velocity of Fc+ is faster than Fc. The standard rate constant tested is 2.79 cm/s.

In order to analyze the energy loss of a beam at crystal surfaces, a method was proposed to calculate the corresponding reflectivity and transmissivity. According to the electromagnetic boundary conditions and the phase matching conditions, reflection and refraction of a beam incident from a crystal upon an isotropic medium were studied, and the Fresnel formulas at the interface between the crystal and the isotropic medium were deduced. As the orientation of optical axis is arbitrary, the polarization states and the amplitudes of the o ray and e ray and the refracted ray were given, and the theoretical expressions of the reflectivity and the transmissivity representing energy relations between the rays were obtained, which provide a theoretical basis for developing and applying crystal devices. Numerical simulations show that the results are accordant with conservation of energy; electrical field or magnetic field of the ray refracted to the isotropic medium does not parallel to the electric field or the magnetic field of original incident ray; the direction of optical axis and the magnitude of incident angle have a great effect on the energy and the polarization direction of the refracted ray.

The adsorption competitive adsorption and conversion behaviors of thiophene and 1?hexene on Hβ molecular sieve have been studied by using the method of in?situ infrared spectroscopyThe roles of different acidic sites in the alkylation reaction of thiophene and olefin molecule were systematically discussed. The results show that 1?hexene is preferentially adsorbed on the B acid sites, and it s easy to dimerize through protonation activation. Thus,there is a significant competitive relationship between the adsorption of thiophene molecules and the protonation reaction process. Moreover, it can be confirmed that the adsorbed thiophene molecule on non?framework aluminum on zeolite are more likely to its alkylation with a protonation 1?hexene molecule near the center of the B acidThis results can provide basic theoretical guidance for the development of zeolite catalysts for alkylation desulfurization processes.

With the rapid development of industry, the negative impact of the use of fossil fuels on the ecological environment is becoming more and more prominent. Among them, CO2, as the main greenhouse gas, causes serious harm to global climate change. The selective hydrogenation of CO2 to methanol is one of the important ways to solve the greenhouse effect, develop green energy and realize sustainable economic development. Copper⁃based catalysts are widely employed for CO2 hydrogenation to methanol due to their excellent catalytic performance and low cost. The difference in reaction mechanism is due to the highly adjustable chemical and electronic properties of copper⁃based catalysts, resulting in the different catalytic performance. This article reviewed the representative reaction mechanism of selective hydrogenation of CO2 to methanol over copper⁃based catalysts was presented, aiming to provided a theoretical guidance for the design of efficient and stable copper⁃based catalysts.

High?nuclear silver clusters have recently received increasing attention owing to their interesting electronic structures and diverse geometric structures. According to Lewis acid?base theory and coordination chemistry theory, silver ions, as acidic centers that provide empty orbitals, often combine with organic ligands that carry lone pairs of electrons as basic centers to form stable coordination compounds. Alkynyl, thiol, and organic phosphine ligands have been widely used to coordinate with silver(I) ions to form silver clusters with various structures. This paper introduced the research progress of the silver chalcogenide clusters constructed by tert?butyl mercaptan ligand, as well as the synthesis methods and structures of silver chalcogenide clusters with different configurations, and explored its potential luminescence and electrochemical properties. The application prospects and development directions of silver chalcogenide clusters was prospected.

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.

The composite PCM was prepared by vacuum impregnation method. Natural bentonite and lauric acid (LA) were used as supporting material and PCM, respectively. The results show that the addition of flake graphite not only improves the thermal conductivity of the composite phase change material, but also prevents the phase change material from leaking out of the composite phase change. After 200 thermal⁃cold cycling treatment, the prepared form⁃stable composite PCM still shows a good performance of thermal reliability and has potential to be used in the thermal energy storage system.

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.

The study of ultrasonic variable amplitude rods is an important part of ultrasonic vibration system. The cosine half?period cylindrical composite horn was designed to realize the smooth transition between the cosine section and the cylindrical section. By theoretical calculation, its frequency equation and amplification coefficient equation were derived. The results show that the frequency equation of the new cosine cylindrical composite variable amplitude rod is simpler than that of the cylindrical conical composite variable amplitude rod and the stepped variable amplitude rod; the amplification coefficient equation of the new cosine cylindrical composite variable amplitude rod is similar to that of the stepped variable amplitude rod, which is more concise than that of the cylindrical conical composite variable amplitude rod. Using ABAQUS finite element analysis software, modal analysis of the designed cosine cylindrical composite variable amplitude rod was carried out to determine its inherent frequency and vibration type; harmonic response analysis was conducted to check the feasibility of the theoretical design. The results of the modal analysis and harmonic response analysis show that the performance of the ultrasonic composite variable amplitude rod is optimal when the length of the cosine section is 55 and 60 mm. The research results provide a reference for the design and application of ultrasonic composite amplitude rod.

A modified dicyandiamide?formaldehyde decolorizing flocculant was prepared using cyclohexylamine as modifier, and was used to simulate dye wastewater decolorization, flocculation and sedimentation experiments. The effect of reaction temperature, reaction time, material molar ratio and other factors on the decolorization performance of the modified flocculation was studied. The results show that reaction time is 3.5 h, reaction temperature is 85 ℃, material molar ratio of dicyandiamide to formaldehyde to ammonium chloride to cyclohexylamine is 1.00∶3.00∶0.50∶0.15, the decolorization rate 88.6% is achieved at a modified flocculant dosage of 100 mg/L. The decolorization and flocculation performance of the dicyandiamide?formaldehyde modified decolorizer is obviously better than that of the unmodified product.

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.

Pollution caused by petroleum?based plastic products has become a problem that is difficult for human beings to solve, and the existing treatment methods are both energy?consuming and easy to cause secondary pollution. The study found that the bacteria that degrade plastic in the intestines of Galleria mellonella (Lepidoptera: Pyralidae) larvae can effectively accelerate the degradation of plastics. This experiment uses polystyrene (PS) packaging boxes, which are common in life, as the only food source to feed the larvae of the large wax borer, enriching the PS?degrading bacteria in the intestines of the G. mellonella larvae. After dissection, culture, and isolation, four strains were obtained: PD?1, PD?2, PD?3 and PD?4. The degradation capacity of MSM culture medium with PS film as the only carbon source was inoculated with each strain, and the degradation rate of PD?1 on PS film was the highest, which was 1.8%. PD?1 was observed by strain morphology, physiological biochemical determination and phylogenetic tree construction, and it was identified as Enterobacter colebella (Klebsiella). Meanwhile, the method of UV and nitric acid pretreatment of PS film were used to improve the degradation rate of the strain, and the results showed that the weight loss rate of PD?1 degradation of nitric acid?treated PS film was improved, which was 2.5%, while the UV group was 0.8%, indicating that PS film was more easily degraded by PD?1 after nitric acid treatment.

In order to better deal with the oily sludge produced in the process of oil production, gathering and transportation as well as oil refining, and in line with the current development trend of environment⁃friendly chemicals in the petrochemical industry, it is very important to use environmentally friendly and low toxic and non⁃toxic chemical reagents in the neighborhood of sewage treatment. This paper introduces a new cleaning agent for oil sludge. Compared with the traditional cleaning agent, the new cleaning agent uses natural chemical derivatives (environmental friendly plant solvent is the main component), which has the characteristics of low toxicity, low pollution and high cleaning efficiency. The use temperature is 5~10 ℃ lower than the field use temperature, further reducing the use of energy. Under the synergism of composite cleaning agent, the residual oil rate in the cleaned sludge can be less than 2%, which has a wide and excellent application prospect.

he biomass conversion to small molecule by gasification through pyrolysis is an important driving force to realize the replacement of fossil energy with bioenergy. Gasification through microwave⁃assisted pyrolysis is a common route for conversion of biomass to desired bioenergy and bioproducts. The review describes the technology of microwave enhanced pyrolysis and microwave⁃assisted catalytic gasification. In addition, this review discusses both the challenges and opportunities of biomass pyrolysis using microwave heating and the milestones that are necessary to be obtained in the future

Collapsible loess is prone to self weight collapse after soaking. The strength of loess will be greatly reduced, and it will threaten the safe operation of buried pipelines along the way. In order to study the stability of buried pipelines in collapsible loess regions, the displacements, stresses and strains of different pipe outer diameters and wall thicknesses during collapsing were analyzed based on the finite element method. The limit length that the buried pipeline could withstand in the loess disaster under certain conditions was obtained by the eigenvalue buckling theory. The results show that: increasing the outer diameter and wall thickness of the pipeline and reducing the buried depth of the pipeline in the loess can effectively reduce the displacement of the pipeline in the collapsible loess; and increasing the outer diameter and wall thickness of the pipeline can also effectively avoid the phenomenon that the local stress of the pipeline is too high; the maximum stress and strain of the pipeline occur at the center of the collapsing zone and the fixed ends on both sides; according to the buckling eigenvalue theory, the ultimate length of the collapsible area of the pipeline is about 65 m when the soil mass has self weight collapsible, and increasing the outer diameter and wall thickness of the pipeline can enhance the buckling resistance of buried pipelines when self weight collapse after soaking.

Thiacalix[4]arene ligands have the advantages of high recognition, derivatization, excellent stability and other advantages. Lanthanide (Ln) ions can coordinate with thiacalix[4]arene ligands to form multi?functional coordination clusters, which received increasing attention due to their unique catalytic, magnetic, optical properties. Thiacalix[4]arene can sensitize Ln ions to luminescence by the coordination of phenol and S groups via the "Antenna effect". This paper reviewed recent advances in structures, luminescent properties, and applications of luminescent Ln?thiacalix[4]arene complexes.

Rigid body displacement method is one of the important methods of compliant mechanism design. Based on rigid body displacement method, choosing the proper space configuration, using the proper flexible joint to replace the rigid motion, then a compliant parallel mechanism micro platform was designed with three degrees of freedom by calculating the freedom of spatial parallel mechanisms based on Kutzbach Grubler theory. The displacement data of moving platform output node was obtained and the movement precision of the parallel mechanism with three degrees of freedom was validated to meet the design requirements by using the ANSYS Workbench through analyzing the stress and diaplacement of flexible side chain and micro platform. The parameters obtained from the analysis could provide a reference for the optimization of the compliant parallel mechanism with multiple degrees of freedom, and it also provided reference for the design of parallel mechanism with multiple degrees of freedom.

 

The classic hydrodesulfurization technology and nonhydrodesulfurization process such as adsorption desulfurization technology and alkylation desulfurization process have been analyzed and summarized at home and abroad. Catalytic hydrogenation desulfurization technology has been widely used in industry, while the non hydrogenation desulfurization process is receiving more and more people's attention.

Initial defects and working environment will cause different degrees of cracks on the shaft. In order to analyze the effect of cracks on the rotor system, the finite element models of the cracked rotor were established through Jeffcott rotor dynamics model and fracture mechanics theory. The simulation analysis of different crack depths, crack angles and different speeds was carried out, and then a mechanical comprehensive failure table was used to carry out experimental research on part of the cracked rotors. The results show that: the appearance of cracks causes high?order frequency doubling components such as 2X in the vibration response of the system, and the phenomenon of depressions or even ferrules appeared in the axis track, and the vibration amplitude increases accordingly. As the crack deepens, the instability of the system gradually increases. The change of the crack inclination angle also affects the vibration characteristics of the system, and the 45?degree crack has the greatest impact on the system. When the speed starts to increase, the influence of the cracks on the system gradually decreases, the time?domain waveform tends to be stable, and the axis trajectory gradually changes back to an ellipse. Finally, the experimental results were compared with the simulation data to verify the conclusions of simulation and modeling.

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.

The dust removal characteristics and working mechanism of the current four major types of dust collectors were reviewed. It mainly focused on electrostatic precipitator technology, introduced its research status at home and abroad in recent years, analyzed the influence of many different factors (equipment structure parameters, gas characteristics, dust properties) on the efficiency of electrostatic precipitator equipment, and summarized electrostatic precipitator. The current technical shortcomings of the collector: The selection of the discharge electrode, the optimization of the best parameters, the anti?corrosion and cleaning of the dust collecting plate. In the future, the following issues should be focued on: development of discharge electrode materials suitable for new forms of electrostatic precipitators, discharge characteristics and dust removal efficiency in complex atmospheres, reduced insulation performance at the dust collector, and corrosion protection.

The effect of soaking temperature and stirring rate on the corrosion behavior of Q235 and Q345 steel in simulated seawater environment (3.5%NaCl) was investigated by using soaking experiment. The surface morphology and chemical composition of corrosion products were analyzed by means of SEM and EDS. The results show that the corrosion rate of Q235 and Q345 steel has little difference and increase with increasing temperature in static seawater environment, reaching approximately 0.28 mm/a at 40 ℃. The stirring rate has a significant effect on the corrosion behavior of Q235 and Q345 steel and the corrosion rate accelerates with increasing stirring rate. When stirring rate is 300 r/min, the corrosion rate reaches 1 mm/a that is about 3.5 times as big as temperature effect. Uniform corrosion was observed on Q235 steel in simulated seawater. But the local corrosion morphology is found on Q345 steel and the main corrosion product is iron oxides. The application of Q345 material should be cautious compared with Q235 material in the same seawater environment.

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.

The pneumatic transmit experiments with the size of sand of 1.2 mm were carried out with compressed air as pumped in the T pipeline experimental bench. Numerical simulation analysis is carried out of the pneumatic transmit process under different condition of the transmission flow and pressure, whereas the change of pressure drop and gassolid two phase volume fraction in branch pipe was achieved. Numerical simulation results show that, pressure drop is proportional to the transmission flow and pressure in the lower part of the pipe, whereas particle volume fraction is inversely proportional to the transmission flow but proportional to transmission pressure. Gas volume fraction is proportional to flow, but it is inversely proportional to pressure. The simulation results are in good accordance with the experiment results. The study provides relevant basis for the further research of the pneumatic conveying.

Through the improvement of small excavator hydraulic system, by using AMESim software and establishing a simulation model of excavator boom hydraulic system, the influence of PID controller parameters on the system dynamic performance was analyzed. At the same time, its dynamic performance was simulated and analyzed. The results show that the global optimal solution of PID parameters improves the performance of excavator boom hydraulic system and obtains good effect, which offers references for the frequency response speed and stability of the system.

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.

Thirty indexes were chose from company profits quality. The nine factors were extracted by factor analysis method. Then the finance performance of the medicine listed industry was evaluated in China by cluster analysis. The results show that the enterprise asset utilization ability, main business profitability and the ability to collect cash were weak.