By constructing a skeleton model of MCM?41 loaded with various functional groups, the adsorption and diffusion properties of water molecules in McM?41 pores with different hydrophilic and hydrophobic properties were calculated by GCMC and MD simulations. The results show that the water adsorption isotherms of MCM?41 materials are mainly Ⅱ type. Hydrophilic functional groups loaded on MCM?41 pore surface can form hydrogen bonds with water molecules, so the interaction force on water molecules is about 114.27% higher than that of hydrophobic functional groups. The diffusion capacity of water molecules in the hole of MCM?41 is positively correlated with the hydrophilicity of surface functional groups, and the diffusion coefficient of water molecules in the material with hydrophilic surface is about 58.82% higher than that of the hydrophobic surface. It was proved that MCM?41 material with hydrophilic surface can promote the adsorption and diffusion behavior of water molecules in pores in aqueous environment.
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 florisil was used as adsorbent for the removal of ammonia nitrogen from low concentration petrochemical wastewater. The florisil was characterized by BET, SEM and XRF, respectively. The effects of the ratio of agent to liquid, adsorption time, pH, adsorption temperature and initial mass concentration of ammonia nitrogen on the effect of adsorption and removal of ammonia nitrogen were investigated. The results show that when the initial concentration of ammonia nitrogen is 50.00 mg/L, the ratio of agent to liquid is 2 g/L, pH value is 7, the adsorption temperature is 293.15 K, and the adsorption time is 5 min, the adsorption effect of the florisil presented superior performance. When the petrochemical wastewater with low concentration of ammonia nitrogen is treated under these conditions, the ammonia nitrogen concentration decreased from 17.53 mg/L to 5.16 mg/L, and the removal rate reached 70.6%, meeting the emission standard of GB 31570-2015.
Using sludge from municipal sewage treatment plants as raw materials, sodium bicarbonate as green activator, and ammonium phosphate as nitrogen and phosphorus source, modified sludge biochar was prepared by vacuum pyrolysis. SEM and FT?IR were used to characterize and analyze the materials. The results show that the modified sludge biochar can significantly increase the specific surface area and porosity of the biochar, as well as the number of N-H and C-O. By changing the dosage of modified sludge biochar, pollutant mass concentration, reaction temperature and pH value and other conditions, the effect of modified sludge biochar on phenol adsorption was studied, and the adsorption process and mechanism were studied. The results show that the modified sludge biochar has a better adsorption effect on phenols, and the adsorption rate increases with the increase in the dosage of sludge biochar; when the pollutant mass concentration increases, the adsorption rate decreases; the higher the temperature, the better the adsorption effect; the acidic conditions are more suitable for the reaction. The adsorption process of modified sludge biochar for phenols conforms to quasi?second?order kinetics, and the adsorption mechanisms are monolayer adsorption and uneven surface adsorption. Modified sludge biochar has good recyclability and it can provide an effective way for the resource utilization of sludge and the treatment of phenols in wastewater.
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.
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.
In this work, the HTO (H4x/3Ti2-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.
Carbonate cementation is one of the key factors to search for oil and gas exploration Sweet spots in low porosity and low permeability or deep sandstone reservoirs. Summarizing the research results of scholars at home and abroad is of great significance for guiding the exploration of favorable zones and the potential of remaining oil. Firstly, the types and distribution characteristics of carbonate cements in oil?bearing basins in China were systematically summarized, and it is considered that their distribution is characterized by diverse basin types, large age spans, and sedimentary facies dominated by abundant delta facies. It is mainly composed of calcite and dolomite, and can be further subdivided into three types of iron?free, iron?bearing and iron?carbonate cements according to the content of iron ions. Then it is concluded that the source and flow of fluid in diagenesis play an important role in controlling the type, genetic mechanism and distribution of carbonate cement by analyzing and summarizing the formation stage, material source, ion migration and precipitation factors of carbonate cement. In the end, several viewpoints on the influence of carbonate cements on reservoir quality were summarized, and some suggestions on the evaluation of the influence of carbonate cements on reservoir quality and some difficult problems to be further studied were put forward.
Taking well group M of E+K block of YH condensate gas reservoir as a typical example, a numerical simulation model of a typical well group was established to study the main controlling factors and mechanism of EOR by gas injection. The effects of different factors including injection?production positions, injection medium, gas injection volume, injection?production ratio, gas injection timing and pressure recovery degree, on the production performance was simulated and the gas injection scheme of the well group was optimized. The results show that the development of retrograde condensate gas reservoir is optimized under the conditions of "up?down production", cyclic gas injection, gas injection volume（30.50～36.60）×104 m3/d （annual gas injection volume is 2.50%~3.00% of the original geological reserves） and maintain high formation pressure (depleted to no less than the dew point pressure). The research results can provide a basis for the policy formulation of EOR technology in the middle and late stage of gas injection development of YH retrograde condensate gas field and provide guidance for the development adjustment of the gas field in the middle and late stage.
With the wide application of clean energy, improving the transportation efficiency of gas pipeline has become a hot issue, among which, it is very important to reduce the friction resistance in the pipeline transportation process. In order to explore the application effect of triangular riblet in the drag reduction of gas pipeline, ANSYS?FLUENT software was used to numerically simulate the turbulent flow in smooth pipeline and riblet pipeline. The results show that: in the near wall area, the velocity profile of ribbed pipe and smooth pipe has a big difference, and the difference is small in the mainstream area. The drag reduction effect of riblet structure is mainly based on the near?wall surface. The riblet structure pushes the vortex away from the wall surface, filling the rib bottom with low?speed fluid, reducing momentum exchange near the wall surface and friction resistance. Compared with the smooth wall surface, the riblet structure with the size of s＝h＝0.516 5 mm has a drag reduction effect of 4.38%.
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.
Based on the discrete element method, this paper uses modeling software Solidworks and discrete element simulation software EDEM to simulate the transport movement of solid particles in a single?screw extruder. The research includes the influence of material parameters such as the shape and size of the particles, the screw speed, and structural parameters such as the number of screw edges and the inclination angle of the screw edges on the solid transport capacity, as well as the movement and filling of the particles inside the barrel. The results show that the single screw?barrel model has the best particle size and the best particle shape; the smaller the particle size, the better the filling effect; the maximum particle transport capacity is when the spiral angle is 105°.
The dry point of gasoline on the top of atmospheric tower is closely related to product quality, but it is difficult to measure the gasoline dry point online, and the soft sensor is a technical way to solve the estimation and control prediction of such variables. Due to the complexity of atmospheric and vacuum distillation process, the correlation between the variables increases. In this paper, sparse principal component analysis (SPCA) was introduced into kernel principal component analysis（KPCA） algorithm, and the input variables of the model were selected by sparse kernel principal component analysis（SKPCA） algorithm. The nonlinear dimensionality reduction between data was realized, the principal component structure was simplified, and the sparsity of principal component variables was increased. The selected sparse principal components were used as the input of the least squares support vector machine (LSSVM), and the soft sensor prediction model for the top dry point of atmospheric tower was established. The simulation results show that the SKPCA?LSSVM model has higher prediction accuracy and superior model performance compared with the traditional PCA?LSSVM and KPCA?LSSVM methods.
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.
With the high?quality development of state?owned enterprises in the new era, it is imperative to promote the transformation and upgrading of high?quality enterprises by realizing power conversion, promoting efficiency transformation, and improving innovation capacity. Taking a large state?owned refining and petrochemical engineering enterprise （hereinafter referred to as S enterprise） as an example, focusing on the personnel management of the general contracting project of refining and chemical engineering construction, a set of quota management system with industry leading and demonstration effect was built. Based on the overall sample range of the saturation sampling method, the correlation causes of labor and employment data were studied, and statistical theory and techniques were used to build a research model, and carried out correlation analysis and variable collinearity diagnosis, with assistance of the characteristics distribution scatter plot and significance test and other scientific index methods to optimize model parameter, comprehensively determining the labour requirement optimal scheme, so as to realize the quantitative load analysis and multi?dimensional monitoring analysis of enterprise labor employment, and labor management risk prevention and control.
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..
