By using methyl methacrylate (MMA) as the harder monomer, butyl acrylate (BA) as the softer monomer, acrylic acid (AA) as the functional monomer, acetoacetoxyethyl methacrylate (AAEM) as the crosslinking monomer, tert⁃butyl peroxybenzoate as the initiator, propylene glycol butyl ether as the solvent for prepared self⁃crosslinking acrylate emulsion by free radical solution polymerization and phase inversion, and the emulsion could be self⁃crosslinked after baking at high temperature without additional crosslinking agent. This article mainly studied the influence of acrylic acid, acetoacetoxyethyl methacrylate and curing time on the performance of the polyacrylic resin dispersion and the film property. The results show that the optimized formula is as follows: The dosage of AA and AAEM are 3.5% and 5.0% of the total monomer mass, respectively, and the baking time is 1.0 h at a curing temperature of 180 ℃. FT⁃IR and GPC analysis showed that AAEM was successfully attached to the molecular chain of acrylic resin; SEM and particle size analyzer analysis showed that the TG of the film is latex particles were spherical and uniformly distributed; DSC analysis showed that after the synthesized resin dispersion is significantly increased after the synthesized resin dispersion is baked at high temperature for a period of time.

The Cu/Fe catalyst was prepared by displacement method and characterized by X⁃ray diffraction (XRD). The degradation effect of Orange II by persulfate (PS) catalyzed by Cu/Fe and its influence factors were investigated, and the mechanism of degradation was also investigated. The experimental results show that Cu/Fe can catalyze PS to degradate Orange II wastewater successfully, and its catalytic effect is better than that of zero⁃valent iron. When pH=3, the mass concentration of PS is 2.0 g/L, the quality of Cu/Fe catalyst at a concentration of 0.250 g/L, the degradation rate of Orange II is up to 99%. The t⁃butanol and methanol are used as radical scavengers to confirmed that the active radicals in the process of degradation are SO〖_4^-〗· and ·OH.

A mononuclear cobalt complex [Co(H2L)(phen)2(H2O)]·4H2O (H2L2-=4,5⁃dihydroxy⁃1,3⁃disulfonate ion, phen=1,10⁃phenanthroline) was synthesized by hydrothermal method. The composition and structure of the complex were characterized by X ray single crystal diffraction, elemental analysis and thermogravimetric analysis. Single crystal diffraction study shows that the cobalt ion is six⁃coordinated, which can coordinate with the four nitrogen atoms of two phen ligands and the oxygen atoms of water molecule and sulfonate group, forming the twisted octahedral configuration in the complex. Compared with the ligand, the fluorescence emission peak of the complex has a blue shift, and the maximum emission peak is at 380 nm.

As an excellent nucleophile, 1⁃hydroxytryptamine derivatives have been widely used in the synthesis in recent years. With the development of indole alkaloids, 1⁃hydroxytryptamine derivatives will play an important role in the future research. In this paper, 1⁃hydroxytryptamine derivatives were synthesized by tryptamine synthesis method with indole substituted by benzene ring as substrate, protection of nitrogen atom in side chain of tryptamine, reduction of indole ring and oxidation of nitrogen atom in indole ring. Finally, the synthesis of the 1⁃hydroxytryptamine derivative was completed in a medium or higher yield. By this method, we synthesized a series of 1⁃hydroxytryptamine derivatives, and confirmed the accuracy of the structure of the compounds by 1H⁃NMR and 13C⁃NMR.

A novel preparation method of smart responsive glass sphere based composite carriers was reported in this study. Firstly, random block copolymers were synthesized by free radical polymerization of N⁃isopropylacrylamide, hydroxypropyl methacrylate and 3⁃trimethoxysilypropyl methacrylate. Then, the copolymer solution was uniformly sprayed on the surfaces of glass spheres by means of a self⁃made bottom spray fluidized bed reactor, and the bonding between copolymers and glass spheres was fabricated by thermal annealing, so as to form the copolymer/glass sphere composite carriers. The coating effects of the smart copolymers on the surfaces of glass spheres were investigated, including characteristic functional groups, surface microstructure, biocompatibility and thermosensibility. The results show that the temperature⁃responsive copolymers can be linked to the surfaces of glass spheres by bottom⁃spray coating technology, and the copolymer layers with certain thickness can be formed on the sphere surfaces. The composite carriers have good biocompatibility, and can realize effective cell adhesion and spontaneous desorption by using its intelligent response characteristics.

The adsorption properties of carbonaceous adsorbents (such as, activated carbon, biochar, CNTs and carbon⁃silica composites) for VOCs were summarized in this paper. The influence of the structure of adsorbents, the characteristics of VOCs, the humidity and the adsorption temperature were analyzed respectively. The development prospect of carbonaceous adsorbents in the future VOCs adsorption process was proposed. While continuously increasing the adsorption capacity of carbonaceous adsorbented for VOCs, improving the performance of recycling, reducing the impact of high⁃temperature and humidity environments on the adsorption capacity in industrial production was a new trend in the research and development of carbonaceous adsorbents in the future.

During the shale gas drainage test stage, the wellhead pressure and temperature are very high, and the produced gas contains a large amount of saturated water, which affects the normal operation of process equipment and gas production pipeline in the test platform. Based on this, on⁃site sampling and test analysis of saturated water were conducted to explore the cause of the effusion in the test platform. Aiming at the reason of liquid accumulation, the scheme of installing partition wall heat exchanger in front of the corrugated plate separator is proposed to reduce the airflow temperature and saturated water content at the inlet of the corrugated plate separator, and Fluent software is used to change the airflow temperature inside the heat exchange tube The situation was simulated. The results show that the average temperature of the air flow in the heat exchange tube can be cooled from 60.34 ℃ at the inlet to 30.00 ℃ at the outlet. The saturated water content can be reduced to 0.731 g/m3 by formula calculation. At the same time, the proposal of installing a hydrophobic hook in the flow channel of the corrugated plate separator is also proposed, and the separation characteristics of the streamlined and hooked corrugated plate separator are analyzed by Fluent software. The results show that the hooked corrugated plate the separation efficiency of droplets can be increased from 28.90% to 76.50%. When the droplet size reaches above 35 μm, the separation efficiency can reach up to 90.00%. The research results have important guiding significance for solving the problem of shale gas test platform liquid accumulation.

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.

The settlement of thermal insulation materials for overhead heavy oil injection pipelines will have a significant impact on the assessment of pipeline heat loss and calculation of economic benefits. A heat transfer model of the heat⁃insulating material settlement steam injection pipeline was established, and the effects of environmental wind speed, pipeline diameter and soil radiation on pipeline heat loss were analyzed.The results show that increasing the outdoor environment wind speed leads to increased heat loss of the eccentric insulation pipe, and when the environmental wind speed increases by 120%, the heat loss outside the pipeline insulation increases by 5.9%. The larger the pipe diameter, the smaller the heat loss of the air interlayer. The average heat flux of the outer wall of the insulated eccentric insulation pipeline is reduced by 1 036 W/m2 compared with the soil radiation.

The spindle is the core part of the high speed milling machine, its dynamic characteristics directly affect the machining accuracy of the milling machine.Taking a German GMN high⁃speed milling machine electric spindle as an example, the finite element method was used to establish a finite element model of the spindle⁃bearing system, the natural vibration characteristics of the spindle were studied, and the influence of bearing stiffness on the natural vibration mode and critical speed of the spindle was analyzed.On this basis, the unbalanced response characteristics of the high⁃speed spindle were studied, and the influence of the unbalance amount and position on the vibration sensitivity of the spindle was analyzed. It was found that the unbalanced response at both ends of the spindle was sensitive, especially at the end where the tool was connected. The results could provide a certain reference for the dynamic design of the high⁃speed machine tool spindle system.

In addition to the light oil which is easy to be exploited, there are many heavy oil which can not be directly exploited in the underground oil reservoir. The heavy oil reservoir is usually exploited by means of steam injection and thermal recovery. Steam dryness is an important parameter to measure the quality of wet saturated steam in heavy oil thermal recovery process, which has an important impact on the efficiency of heavy oil thermal recovery. In this paper, a new method of measuring the dryness of wet saturated steam in steam injection pipeline matrix conductance method was proposed. Based on this method, combining the thermodynamic properties of water and steam, an algorithm model of matrix conductance method for measuring the dryness of wet saturated steam was established. The causes of measurement errors and the methods to reduce the errors were analyzed. The calculation of the edge area of the instantaneous cross⁃section water area under the matrix was interpolated. Finally, the absolute error of the algorithm model was less than ±3.0%. This study also provided a reliable method for real⁃time monitoring of steam dryness, which was of great significance for improving the efficiency of heavy oil thermal recovery.

In engineering design, special area of pressure vessels always needs opening nozzles in order to satisfy complexity of technologies. Only considering the single load condition of the pressure vessels, the calculation of opening⁃nozzles in GB 150—2011 does not involve additional external load on opening⁃nozzles in practical projects. The SolidWorks software was used to locally model the tangentially opened pressure vessel of the cylinder, and the finite element analysis method was used to apply two internal conditions of the internal pressure and the external load of the internal pressure to the three⁃dimensional solid model to obtain the structural stress. Distribution and strength evaluation were carried out, and the influence of the additional external load on the structure of the pressure vessel was studied.The results show that the stress value in nozzle⁃vessel junction area increases sharply and it changes symmetrical distribution of stress in the connection between the nozzle and the vessel because of the external load of the nozzles. The analyzing results can provide some reference in stress analysis of the opening⁃nozzles with the united static load.

For the multi⁃performance evaluation model in the complex coking production process, the evaluation index is single, and the evaluation index can only reflect the production one⁃sidedly.The process without considering the problem of global factors, use the Analytic Hierarchy Process (AHP) to comprehensively consider safety, stability and economic aspects, and establish a global performance evaluation model. In order to solve the problem that decision makers are more likely to assign uncertainties to multiple indicators, use the intuitionistic fuzzy set (IFS) to obtain the preference relationship including membership degree, non⁃membership degree and hesitation degree. Consider the irrationality of consistency threshold, introduce a new threshold, and use entropy and cross entropy to calculate the index weight, and finally obtain the performance state of the target system. Finally, two different operating states of the coking production process were evaluated to prove the effectiveness and feasibility of the IFAHP method.

In order to improve the realism of the simulated scene, weathering the objects of the image is an effective method. Using an image processing method to achieve the fine weathering effect of the objects surface in the image. First of all, use the radial basis function (RBF) method to calculate the weathering degree image. Even if the color of the surface of the object changed greatly, the algorithm could calculate the degree of weathering more accurately. Then, use the image segmentation algorithm to extract the most weathered region as the "weathering exemplar". Finally, the patchmatch image repair algorithm was used to complete the "weathering exemplar", so that the "weathering exemplar" could be propagated seamlessly in the weathering area of the image. The results show that the proposed method can generate various types of weathering effects. Using the method of exemplar propagation can better simulate the weathering image.

A new image encryption method based on rotation transformation and chaos theory was proposed, which used chaos function to generate random phase mask (chaotic random phase mask). In the proposed technique, the image was encrypted using gyrator transform and two chaotic random phase masks. In the proposed method, the image was encrypted by using rotation transform and two chaotic random phase masks, and the chaotic random phase mask was generated by using three chaotic functions: Logistic map, Tent map and Kaplan⁃Yorke map. The computer simulations were presented to verify the validity of the proposed technique. By calculating the mean square deviation, the robustness of the blind decryption algorithm based on the seed value of rotation angle and chaotic random phase was evaluated, and the optical implementation scheme of encryption and decryption technology was given.

Parabolic partial differential equations play an important role in the fields of engineering technology and natural science, especially in the fields of seepage, heat conduction and diffusion. This paper mainly studies the numerical solution of parabolic equations. On the basis of mesh segmentation. First, a differential format with parameters is given. The Taylor series expansion method and the undetermined coefficient method are used to make the truncation error of the difference format reach O(τ^3+h^5). The parameters are determined by the equations to obtain a two⁃layer high⁃precision difference format. Then the Fourier analysis method is used. Solve the condition that achieves stability under this precision, that is r≤(19+√(1 141))/60.The numerical solution is compared with the exact solution by numerical examples, which verifies that the new method is feasible and effective.

Due to its advantages of high energy density and low cost, lithium sulfur battery has become a potential choice for electric vehicles and new energy storage devices. Anode protection has become a hot topic in recent years. By optimizing the anode, lithium dendrites can effectively be alleviated which can solve the problem of battery cycle life decreasing. In this paper, the strategy of anode protection for lithium sulfur battery was introduced from the aspects of electrolyte additive and anode structure design, and the mechanism of action was briefly described. Finally, the strategy development of lithium sulfur battery anode protection was prospected.

 

A layered coordination polymer, [Ce(L)(H₂O)₄]_n (1), was synthesized by hydrothermal method by the reaction of 5⁃sulfoisophthalic acid monosodium salt (NaH₂L) with cerium nitrate hexahydrate. Its molecular structure and composition were measured by single crystal diffraction, elemental analysis and thermogravimetry. Each Ce³⁺ was nine coordinated with the coordination geometry of three⁃capped triangular prism. The central Ce³⁺ could be bridged by the carboxylate and sulfonate groups of the L^3- ligands, forming a two⁃dimensional layered structure. The interlayers were connected by the hydrogen bonds between the coordination water molecules and oxygen atoms of functional groups, increasing the stability of the structure. The fluorescence measurement results show that compound 1 exhibits the characteristic fluorescence emission peak of the ligand at 427 nm. It also has the second⁃order nonlinear optical property, and its intensity is 0.7 times of that of potassium dihydrogen phosphate (KDP).

A variety of novel chiral phosphoric acid catalysts were synthesized from R⁃binaphthol via hydroxyl protection, halogenation, coupling, deprotection, phosphorylation and hydrolysis. The chiral phosphoric acid catalysts synthesized were mainly chiral phosphoric acid catalysts with nitro substituents, because the addition of nitro substituents could increase the acidity of phosphoric acid and provide a catalyst for some reactions requiring a stronger acidic catalytic system. By our method, about 10 g of nitro⁃substituted chiral phosphoric acid catalyst could be synthesized in one time in a high yield, which provided great convenience for asymmetric catalytic reaction.

2⁃Phenylthioethanol was synthesized from thiophenol and ethylene carbonate using 1,5⁃diazabicyclo[4.3.0]non⁃5⁃ene (DBN) as a catalyst. The effects of catalyst type and amount, reaction time and temperature on the reaction were studied. The results showed that, the conversion of 2⁃phenylthioethanol can reach more than 90% when the reaction temperature is 50 ℃ and 100% conversion can be obtained when the reaction temperature is 90 ℃ using DBN as the catalyst, n(thiophenol)/n(DBN)=100, the reaction time 10 min. The selectivity of the catalyst of the synthetic route is 100% The paper discusses the reaction mechanism according to the theory of soft and hard acid and alkali.

Titanium alloy is widely used in military and civil fields because of its high strength, corrosion resistance and high specific strength. However, high temperature oxidation reaction will occur when it is used in a high temperature environment, which reduces its performance and limits its application range.Ceramic coatings are prepared in situ on the surface of titanium alloy by means of Micro⁃arc oxidation(MAO) technique. The combining capability of ceramic layer and metal substrate is very strong, has good wear resistance, corrosion resistance and resistance to high temperature and other characteristics, the technological process is simple and efficient, low cost and is friendly to the environment, can greatly improves the oxidation resistance of titanium alloy, prolong its service at high temperatures.This paper reviews the research status of micro⁃arc oxidation technology in the field of high temperature oxidation resistance of titanium alloys.The influences of reaction parameters, electrolyte, reaction time and power mode on the structure and high temperature oxidation resistance of micro⁃arc oxide ceramic coatings are summarized.

Widespread application of PLA is limited because of its slow crystallization rate and low heat deflection temperature. The poly (lactic acid) (PLA) with wood flour (WF) and a small amount of multi amide compound (MA) were successfully prepared by melt blending. The crystallization kinetics, heat resistance and mechanical properties of PLA composites were studied. When the addition of wood flour was 30.0% and multi amide compound was 0.3%, DSC results show that the crystallization rate of isothermal and non⁃isothermal improved dramatically, and correspondingly the Vicatsofting point of PLA composites increases to 146.5 ℃, higher than that of neat PLA 61.6 ℃, the heat resistance of PLA is improved dramatically. Moreover, mechanical properties of the PLA composties are studied. The tensile strength of the PLA/WF and PLA/WF/MA samples is increased slightly. It is concluded that the combination of wood flour and the multi amide compound have a synergistic effect on PLA crystallization behavior to producehigh heat resistance PLA composites.

MnFe2O4/TiO2 Fenton⁃like photocatalyst was successfully prepared by sol⁃gel method, the structure and morphology of the sample were characterized by XRD, SEM and UV⁃vis. MB was used as the target pollutant for degradation, and the photocatalytic properties of products with different doping amounts were investigated in visible light. The results show that: The degradation rate of TMF Fenton⁃like photocatalytic reaction to MB is up to 96.8%, under the optimum conditions, in the iodine⁃tungsten lamp with a light source of 300 W, the doping amount of MnFe2O4 to TiO2 is 2%, the mass of catalyst is 60 mg, pH=11, and the concentration of H2O2 is 8 mmol/L . Under the same conditions, compare with the undoped pure TiO2, the catalytic performance of MnFe2O4/TiO2 for MB under visible light is significantly improved.

In view of the problems of difficult establishment of effective displacement system and poor effect of water drive in Chang 8 reservoir of C335 area of JY oilfield, the reservoir development effect was evaluated comprehensively by reservoir pressure change, water drive law and effect characteristics. On this basis, combining with reservoir engineering and numerical simulation, this article formulated reasonable exploitation policy. The optimum injection⁃production ratio was 2.0, the flow pressure was 6.0 MPa, and the production rate was 0.7%. Finally, by comparing and forecasting the three schemes, the comprehensive scheme was the best.

Under natural conditions, natural gas hydrates are found in marine environments. Therefore, it is necessary to study the formation of hydrates under salt water conditions and their basic properties. The effect of low⁃concentration MgSO4 with sodium dodecyl sulfate (SDS), alkyl glycoside (APG), dodecyl trimethyl ammonium chloride (DTAC) and other surfactants on the formation of hydrates was studied. The changes of pressure and temperature with time during the formation of hydrate were measured under the conditions of 275.15 K and 6 MPa. The results show that when a certain concentration of SDS or APG is added to the solution, the hydrate formation is significantly promoted. When a certain amount of DTAC is added, substantially no hydrate is formed in the solution. Furthermore, low concentration of MgSO4 significantly enhanced the promoting effect of surfactants. It can be seen that low concentration of MgSO4 and appropriate concentration of surfactant will promote the formation of methane hydrate, and different types of surfactants have different effects on the formation of hydrate. Compared with the promotion effect of SDS and APG on hydrate formation, the promotion effect of DTAC on hydrate formation is not obvious.

Construction standardization and civilization are not only the minimum requirements of the construction site, but also the innovation of the construction field in the new era, which are related to the social and economic development and the process of national modernization.Based on the recruitment and bidding information of an oil depot and taking four different construction schemes as the basic data, a standardized construction management evaluation index system was firstly constructed. On this basis, the standardized construction scheme evaluation system was constructed by entropy weight method and comprehensive evaluation method. The results show that the degree of standardization and civilization of the four schemes is ranked as M3＞M4＞M1＞M2. The first⁃level index weight ranking is environment＞safety＞energy saving＞cost＞quality＞progress. Among them, the weight proportion of environment factor is the largest, about 0.193, and the weight proportion of project progress factor is the smallest, about 0.128. Therefore, during the construction of oil depot, the emphasis should be placed on construction environment and safety construction, and the road of green, standardized and sustainable development should be taken.

Aiming at the shortcomings of dynamic risk analysis in large gasification units, a method of dynamic Bayesian network based risk analysis of gasifier feed system was proposed. The fault tree model was established by using the relevant data of failure forms of each unit of gasifier feeding system, and the fault tree model was transformed into a Bayesian network model. The bayesian network model was optimized by K⁃2 algorithm, and the influence of common cause failure on the system was processed by β factor method. Considering the influence of maintenance factors on the failure rate of the system at each moment, the accuracy and feasibility of the proposed method were verified by using the Bayesian network analysis software GeNIe and Monte Carlo. The results show that the dynamic Bayesian network has the advantages of accurate dynamic risk analysis and the ability to identify the weak links in the gasifier feed system risk analysis. According to the analysis results, a reasonable reliability allocation strategy can be obtained.

T⁃shaped multi⁃branch pipeline is a kind of T⁃shaped pipeline with complex multi⁃branch structure, which is now widely used in the research of two⁃phase and multi⁃phase flow.In this article,the fluid simulation tool Fluent was used to simulate the oil and gas two⁃phase flow in the T⁃shaped pipeline at different times with obtained the oil and gas separation characteristics of each branch and the mass flow data of the inlet and outlet.The results indicate that, when the oil and gas two⁃phase mixed infusion flows through the T⁃shaped pipeline, the phase distribution of the oil and gas two⁃phase in the pipeline is uneven due to the effect of gravity.With the increase of time, the gas⁃outlet at the top is mostly gas, while the oil⁃outlet at the bottom is mostly liquid, thus achieving a initial separation of oil and gas. T⁃shaped pipeline with different branch pipe heights are selected for simulation, and the characteristics of oil⁃gas separation phenomena are analyzed. Then select different inlet velocity of T⁃shaped main pipe to observe the effect of inlet velocity on oil⁃gas separation.Finally, by analyzing the turbulent vortex structure and flow field characteristics in the pipeline, the turbulence coherent structure shows the characteristics of regularity and repeatability under the same structural parameters, and the influence of branch pipeline on flow pattern and turbulence vortex.

In view of the shortcomings of the existing accident causation models, such as simple listing and superposition of causative factors, not considering the coupling effect between factors, unable to make quantitative analysis and so on,a new nonlinear multi⁃factor coupling accident causation model was proposed and applied to the prevention of oil depot accidents. In the new model, the calculation formulas of the main influencing factors, the influence coefficient and the multi factor coupling rheological nonlinear damage were proposed. The most prominent feature of the model is that it can distinguish the dynamic influence of the rheology of the main influencing factors on the damage of the complex system under the coupling action of multiple factors. MATLAB software was used to simulate the changing state of the oil depot system after single factor rheology, main influencing factor rheology and non⁃main influencing factor rheology. The results show that the main factor affecting the safety of oil depot is the lack of safety consciousness,and the lack of safety consciousness of oil depot personnel has the greatest influence on other factors. For oil depot accident prevention, according to the nonlinear multi⁃factor coupling accident cause model proposed in this paper, it is necessary to take effective measures to control the main influencing factors and seize the main time nodes.

To solve the problem of distribution network fault line selection caused by too few frequency components and no high amplitude low frequency components in the characteristic frequency band of transient zero sequence current, an improved ensemble empirical mode decomposition (MEEMD) method is proposed. Firstly, the influence of distributed generation on line zero sequence current was considered; then, the zero sequence current after fault was decomposed into multiple frequency signals according to frequency by meemd, and the eigenmode function was obtained and the highest frequency component is extracted; finally, the line selection result was obtained by analyzing the signal waveform of the highest frequency. The basic signal was not needed in this process, so the characteristics of the obtained signal were closer to the original signal. The process of fault line selection based on meemd was described in detail, and the influence of multi scene distribution network considering distributed generation on fault line selection is discussed. The simulation results show that the method can effectively improve the accuracy of fault line selection.

The problem of H∞ output tracking control for switched time⁃delay systems is investigated by using mode⁃dependent average dwell time method. Using the multiple Lyapunov function method, the condition satisfied by the mode⁃dependent average dwell time was developed, such that the considered systems were exponentially stabilizable with H∞ output tracking performance, the switching controller combining state feedback and tracking error integral was also designed simultaneously. Different from the single average dwell time method, the mode⁃dependent average dwell time method allowed each subsystem of switched systems to possess its own average dwell time, thus it reduced the conservatism of the results. Finally, a numerical example was used to illustrate the effectiveness of the proposed theoretical results.

In order to solve the problem that different users have different expectations for search results in information retrieval, a personalized web search algorithm based on vector space model was proposed.In view of the different interests of users, user portraits could more comprehensively express the characteristics of user interests. The vector space model was used to establish user portraits to express user interests, combined with traditional web page ranking algorithms to obtain the final web page ranking results. Different web search results could be obtained for different users, and the number of web pages that meet user interests increases in the top ranking web pages. Through the analysis of the experimental results of simulated web search, it was proved that this algorithm was better than the traditional PageRank algorithm in personalized web search.

With the development of chemical industry, the discharge of industrial wastewater increase gradually, which has caused serious environmental pollution. Therefore, developing an efficient treatment technology to solve this problem is urgently needed. Photocatalysis is an efficient strategy to remove organic pollutants in aqueous condition. TiO2 is one of the most excellent photocatalytic material to be used in pollutant degradating, due to its higher chemical stability, photocatalytic activity and environmental friendliness. However, TiO2 particles are aggregated easily in aqueous media and difficult to be recycled, which hinders its practical applications. Dispersing TiO2 nanoparticles on the surface of mineral materials can reduce the aggregation of TiO2, increase the number of surface active sites, and improve its photocatalytic activity. This paper reviews new research progress of mineral supported TiO2 composites in photocatalytic degradation of organic pollutants.

Using Marie vacuum residue as raw material, the acetic acid⁃peroxyacetic acid oxidation system was used to pre⁃oxidize the vacuum residue, and N, N⁃dimethylformamide (DMF) was used to extract and remove sulfide in the residue. Under the conditions of m(residue)/m(solvent)=1 ∶ 1, Investigate the effects of oxidant dosage, reaction time and temperature on the removal of sulfur content in residue oil. X⁃ray photoelectron spectroscopy (XPS) and Fourier infrared spectrometer (FT⁃IR) The organic sulfur type distribution and functional groups of the residual oil before and after oxidation were detected. The results show that under the conditions of m(residue oil)/m(solvent)/m(acetic acid⁃peroxyacetic acid)=5 ∶ 5 ∶ 4, oxidation temperature 70 ℃, and oxidation time 50 minutes, the C-S stretching vibration absorption peak of the oxidized residue is obviously weakened. Thiophene type sulfur can be removed by extraction after being oxidized to sulfones. The sulfur content of the residue is reduced from 4.01% to 2.67%, the desulfurization rate reaches 33.37%, and the residue yield is 94.82%.

The composition of Fushun oil shale (OS) was analyzed by Fourier transform infrared spectroscopy (FTIR) and X⁃Ray Diffractomer(XRD).The effects of transition metal salt catalysts (shale ash as a carriers on NiCl ₂·6H ₂O, CuCl ₂·2H ₂O, ZnCl ₂) on the catalytic effect of pyrolysis of OS and precipitation of volatilization were investigated by TG⁃MS. Coats⁃Redfern model was used to analyze the effect of transition metal salt catalyst on the activation energy of OS pyrolysis. The results show that the minerals in OS are mainly composed of quartz, aluminosilicate and a small amount of carbonate, and the organic matter is mainly aliphatic compound. Three transition metal salt catalysts can all promote the pyrolysis of OS. The OS can be rapidly pyrolyzed at 390.1~581.8 ℃ when it is pyrolyzed alone, accounting for 76.19% of the total weight loss. According to the kinetic analysis, the activation energy required by OS pyrolysis can be reduced by the transition metal salt catalysts. NiCl ₂·6H ₂O has the highest capacity (18.7 kJ/mol) to reduce the activation energy of OS pyrolysis, which is 23.55% lower than that of OS pyrolysis alone. The catalytic activity of the transition metal salt catalysts are in a sequence of NiCl ₂·6H ₂O>CuCl ₂·2H ₂O>ZnCl ₂. In addition, the transition metal salt catalysts can also promote the cracking, aromatization and coking of volatiles in the pyrolysis of the OS, Thereby increasing the content of aliphatic hydrocarbons (represented by alkanes and alkenes) and aromatic hydrocarbons in volatiles.

Periconansons C⁃F is a natural product of cytochalasin. Its structure contains a six and six bicyclic skeleton. We think that we can complete the construction of this skeleton structure through one⁃step D⁃A reaction. We synthesized its key D⁃A reaction intermediate.KF is used as base and O2 is used as oxidant to oxidize the required hydroxyl group. After the intramolecular D⁃A reaction, it is possible to complete the total synthesis of four molecules, such as percoannosins C-F.

This paper described the emission situation of pollutants from coal combustion in China, and it was pointed out that the removal technology of fine particulate matter was an important goal to be solved urgently. The research progress of soot control technology for coal burning at home and abroad was reviewed, and the principle, characteristics and research progress of the smoke and dust control technology were introduced. The results show that low⁃low temperature electric dust removal technology, agglomeration technology and synergistic removal technology have become the hot spots of fine particulate emission control technology and have a good application prospect. In addition, the analysis points out the difficulties faced by each part and the development direction, and provides reference for the removal of fine particulate matter from smoke and dust to meet the requirement of ultra⁃low emission standard.