Natural products of glycosides are the main forms of secondary metabolites in plants and have important biological activities. Glycosylation modification can change its water solubility and stability, and produce special biological activities and functions. Therefore, glycoside products are suitable for commercialization and have important medicinal and industrial values. Especially it is widely applied to anti-cancer drugs and daily chemical products, thus glycoside compounds have been concerned and studied. In recent years, the biosynthesis of glycoside products had made great progress. In this paper, the important glycoside compound quercetin is illustrated to introduce the biosynthesis of glycoside compounds, and the engineering strategy of high-yield glycoside compounds is described from the perspective of glycosyltransferase and precursor supply. It provides technological support for researchers to obtain the high-yield strains of plant glycosides by utilizing synthetic biology techniques.

Taking the hydrophilicity and hydrophobicity as the starting point, the research status and development trend of biotrickling filters (BTFs) for industrial waste gas containing multi-component volatile organic compounds (VOCs) are summarized. This paper focuses on antagonistic, synergistic, and mutual effects among multiple VOCs, which summarizes and analyzes the immanent cause leading to the interactions. Besides, the gas-liquid/solid two-phase mass transfer models and biodegradation kinetics models are used to elaborate the VOCs mass transfer and biotransformation processes and their mechanisms in BTFs. Furthermore, application prospect is prospected to satisfy to current market requirement through construction and strengthening of synergistic effect instead of antagonism. And the treatment systems of VOCs are constructed by strengthening theoretical cognition of co-metabolism and solubilization mechanisms, which would promote BTFs developments in two aspects of theory and application.

Isothermal vapor-liquid equilibrium (VLE) data for citral (1) +α-ionone (2), citral (1) +β-ionone (2) and α-ionone (1) +β-ionone (2) were measured at 333.15, 368.15 and 403.15 K using headspace gas chromatography method. Redlich-Kister area test method and van Ness point test method were used to check the thermodynamic consistency. Aspen plus V10.0 software and Britt-Luecke algorithm were used to return the NRTL and UNIQUAC activity coefficient model parameters. Furthermore，the excess Gibbs energy (G^E) for all systems were calculated using the NRTL model. The results showed all experimental p-T-x-y data satisfied the requirements of thermodynamic consistency. The maximum absolute average deviation (AAD) of vapor compositions between calculated and experimental data for citral (1) +α-ionone (2), citral (1) +β-ionone (2) and α-ionone (1) +β-ionone (2) systems at the measured temperatures were 0.0044,0.0060 and 0.0032, respectively. The maximum G^E for three systems were 0.4002, 0.2315 and–0.7143 kJ·mol^-1, respectively.

Ethylene glycol can selectively extract phenols from oils containing aromatic hydrocarbon components. To provide fundamental data to help developing new processes for extracting and separating phenols from coking phenolic oil by ethylene glycol, a simplified design method was adopted due to the complicated components of coking phenolic oil, that was o-cresol and m-xylene chosen as typical substances of phenolic compounds and aromatics based on existing phase equilibrium data, respectively. The ternary liquid-liquid equilibrium data of the o-cresol-m-xylene-ethylene glycol system were measured at 303.15, 313.15 and 323.15 K under atmospheric pressure. The reliability of the liquid-liquid equilibrium data at different temperatures was verified by Othmer-Tobias, Hand as well as Bachman equations. All of squares of correlation coefficients were greater than 0.99, which indicates the reliability of the measured experimental data was good. The experimental data were correlated by both NRTL and UNIQUAC models. The binary interaction energy parameters at different temperatures were obtained by data regression. As a result, the phase equilibrium data were calculated and compared with the experimental data. The root-mean-square deviations (RMSD) were less than 1.8%, indicating that NRTL and UNIQUAC models can successfully describe the phase equilibrium behavior of the system.

Using the density functional theory calculation of quantum chemistry, the reaction mechanism of p-type dopant Cp₂Mg in the metal organic chemical vapor deposition (MOCVD) gas phase process was proposed and studied. The possibility of each reaction proceeding at various temperatures was determined, respectively. It was found that Cp₂Mg mainly has two competing addition paths and hydrogenolysis paths. For adduct reaction path, complex Cp₂Mg∶NH₃ or Cp₂Mg∶(NH₃)₂ will be formed in the temperature range of 293—573 K. For the hydrogenolysis pathway, the H radical in the gas phase was a “double-edged sword”. On the one hand, H radical exerted a positive auxiliary effect on Cp₂Mg decomposition, significantly lowering the decomposition temperature of Cp₂Mg. On the other hand, due to passivation, Mg-H gas phase complexes will be formed, which affects the p-type doping effect.

To provide basic data for the process design and process simulation calculation of solvent extraction and separation of n-hexane-isopropanol mixture, experimental liquid-liquid equilibrium (LLE) data for separation of isopropanol from n-hexane were measured at 30℃ under atmospheric pressure by using dimethyl sulfoxide, 1,4-butanediol, 1,2-propanediol, acetonitrile, furfural and N,N-dimethylformamide as extractants, respectively. The extraction properties of these selected solvents were assessed by the separation factor based on the experimental LLE data. It was found that separation factor were all higher than 1 with above solvents, corroborating that it is feasible to extract isopropanol from n-hexane using the selected extractants. The consistency and reliability of the experimental data were appraised using the Hand equation, and the correlation coefficients of fitting equations were all above 0.98. Furthermore, the non-random two liquids (NRTL) activity coefficient model in Aspen Plus software was utilized to correlate the experimental tie-line compositions, in which the binary interaction parameters between the components were acquired. Subsequently, the corresponding values of phase equilibrium were calculated and compared with the experimental data. As a result, the root mean square deviation (RMSD) between the calculated and experimental compositions was below 1.0%, indicating that the NRTL model can accurately describe the liquid-liquid phase equilibrium of the ternary system.

The design, enlargement, and optimization of fluidized beds require a basic understanding of the watershed. However, the division of watersheds for gas-solid systems still has many controversies. In this paper, the state-of-the-art regime studies are summarized with the main disputes highlighted. Inconsistency is found on the demarcation of the fast fluidization. The steady-state EMMS (energy minimization multi-scale) drag model is thus integrated into two-fluid model (TFM) to simulate a circulating fluidized bed (CFB) with a variety of gas velocities and solids holdups. Particle refluxing and slugging are found in the simulation results, whereby bound the fast fluidization regime. A regime diagram is drawn, where the main features of the different regimes in CFBs are presented.

The external heat extractor is one of the key equipment to maintain the thermal balance of the catalytic cracking reaction system and keep the device running smoothly. It can process feed oils into products with higher value, such as gasoline, diesel, and olefins. The catalytic cracking reaction belongs to a parallel series reaction, and its desired products are the reaction intermediate. Meanwhile, a lot of heat is absorbed during reaction. The heat is mainly provided by coke-burning regeneration of the catalysts in regenerator. When processing heavy oils, the carbon amount on the catalysts will be increased, which can generate the extra heat during the catalysts coke-burning regeneration. A fluidized bed with external catalyst cooler can take the extra heat away to control the reaction temperature effectively and keep the heat balance between reaction and regeneration. The downflow external catalyst coolers have been widely used due to their high heat load and flexible adjustment. Both optimal design and effective control of downflow external coolers in industrial application require a deep understanding of gas-solid flow characteristics, heat transfer characteristics and their correlation. Therefore, a pilot scale cold mode experimental setup was built to investigate the effect of superficial gas velocity and solid mass flux on heat transfer, solid holdup and bubble frequency. The results showed that the instantaneous heat transfer coefficient presented the characteristics of low-frequency and high-amplitude as well as high-frequency and low-amplitude, and the former played a dominate role. The fluctuation periods of instantaneous heat transfer coefficient and instantaneous local solid holdup were both 25 s, which indicated that the heat transfer process between bed and heat transfer tube was directly related to the local solid holdup. Increasing superficial gas velocity can reduce local solid holdup, increase local bubble frequency, and enhance the heat transfer between bed and heat transfer surface. Moreover, local solid holdup and local bubble frequency were increased with solid mass flux. Heat transfer coefficient was decreased with solid mass flux at u_g=0.1 m/s, while increased with solid mass flux at u_g≥0.4 m/s. Influence of gas-solid flow characteristics on heat transfer characteristics was various under different flow patterns of fluidized beds. In bubbling bed flow pattern, local bubble frequency near the heat transfer tubes had a great influence on the heat transfer process, due to high local solid holdup impeded the renewal of particles on the heat exchange surface. In turbulent bed flow pattern, heat transfer coefficient was increased with local solid holdup and bubble frequency. Empirical correlations for predicting heat transfer coefficient at different flow patterns were built based on operation conditions and gas-solid flow characteristics. Their mean relative deviations between predicted value and experimental value were 6.9% and 1.3% respectively.

The heat exchanger is one of the main equipment in the field of petroleum, chemical industry, nuclear energy and other industrial applications. The development of an efficient heat exchanger can effectively improve the energy utilization rate, which is an important way to solve the energy and environmental problems. Shell and plate heat exchanger is a new type of heat exchanger; it combines the advantages of shell and tube heat exchanger and plate heat exchanger. It has high heat transfer efficiency, high temperature and pressure resistance, compact structure and light weight, and makes up for the uneven stress distribution of plate heat exchanger. At present, there are few literature reports on the flow pattern and pressure drop characteristics of gas-water two-phase flow in the shell and plate heat exchanger. In this paper, the flow pattern and pressure drop of the vertical upward gas-liquid two-phase flow in the shell and plate heat exchanger are experimentally studied. The macro distribution characteristics of the vertical upward gas-water two-phase flow interface in the shell and plate heat exchanger are obtained by high-speed camera technology. The flow pattern is divided into bubbly flow, slug flow, film flow and churn flow according to the morphological characteristics of the phase interface; at the same time, the relationship between flow pattern and pressure drop is analyzed, and it is found that the amplitude of pressure drop fluctuation in bubble flow is the smallest, followed by the slug flow and the film flow, and the amplitude of pressure drop fluctuation in the agitated flow is the largest; based on Lockhart-Martinelli theory, the prediction model of two-phase flow pressure drop in the shell and plate heat exchanger is established by analyzing the relationship between two-phase multiplier and Martinelli parameter, it is found that the value of Chisholm parameter C is close to the value of Chisholm's original laminar-laminar flow in smooth tube.

The existing approach of calculating cross-sectional area of the spiral channel of the helical baffle heat exchanger (HBHX) is according to the minimum cross section of the channel throttled by tube row, while the actual cross section of the spiral channel is composed of both the minimum cross section and the maximum cross section at inter tube space, and the spiral flow does not pass through the minimum cross section instantaneously. Thus the prediction has been in vain of the shell side Nusselt number and friction factor with universal correlations of the Reynolds number for helical baffle heat exchangers because of the incorrect value of Reynolds number. A novel model of mass center equivalent rectangle (MCER) is presented for more accurate calculation of the cross-sectional area of the helical flow channel of the HBHX. The verification of the MCER model is performed with satisfactory results for HBHXs by both the heat exchanger commercial design software HTRI and some experimental results in literatures. Under the same conditions, the error between the Nusselt number Nu_o calculated by the MCER model and the result calculated using the heat exchanger design software HTRI is in the range of -10% to 5%, and the errors with the experimental results of the two groups of literature are within the range of ± 18% and -5%—15%, but the error of the friction factor formula results compared with the results of the above sources is relatively large, and needs to be further improved.

Using deionized water as the experimental working medium, an experimental study of the frictional resistance characteristics of subcooled boiling in a narrow rectangular channel under single-sided heating visualization was carried out under low pressure and low flow rate natural circulation conditions. In the experiment study, the pressure drop data in the narrow rectangular test section was measured, high-speed camera was used as well to capture the two-phase flow images, calculation method that separates the two-phase frictional pressure drop in subcooled flow boiling was brought out. Based on the experimental data obtained, evaluation study of classical two-phase frictional pressure drop correlations from homogeneous flow and separated flow modes were carried out. The experimental results indicates that correlations that based on two-phase equivalent viscosity from homogeneous flow models significantly under estimate the friction pressure drop. Sun and Mishiba correlations and Tran correlations from separated flow models can predict the friction pressure drop pretty well with mean relative error under 15% error bands. Based on the experimental data obtained, empirically correlations for two-phase multiplier was obtained by considering the effect of liquid only Reynolds number, Martinelli parameter and Laplace number. The mean relative error of predicted result with the experimental data is within 10% error band.

To investigate the heterogeneous nucleation characteristics of supersaturated water vapor on the surface of fine particles, and accurately predict the nucleation parameters, a molecular kinetic model of heterogeneous nucleation of supersaturated water vapor on the surface of coal-fired fine particles was established based on the theory of molecular kinetic heterogeneous nucleation. The promotion effects and relative importance of two diffusion condensation mechanisms of water and vapor molecules to accelerate embryo growth and the influences of supersaturation and macroscopic contact angle on nucleation rate are systemically analyzed. Furthermore, the critical supersaturation for fine particles under different temperature and macroscopic contact angles are also predicted. The results show that when the radius of embryo is less than critical embryo radius, the ratio of diffusion condensation rate of water molecules absorbed on particle surface to direct vapor deposition condensation rate is always above 100, it indicates that the surface diffusion mechanism of absorbed water molecules plays a dominated role in embryo growth. The nucleation rate is remarkable increased with the increase of supersaturation or the decrease of macroscopic contact angle. Additionally, the nucleation rate increases exponentially with the increase of supersaturation. Increase the vapor temperature or decrease macroscopic contact angle can lead to a lower critical supersaturation. For fine particles with a particle size of less than 0.1 μm, as the fine particle size increases, the critical supersaturation of heterogeneous nucleation decreases significantly.

In this study, an internal heat exchanger organic flash cycle (IHE-OFC) system model was built, using 100—200℃ geothermal water as the heat source, and R600a, R600, R601a, R601, R236ea, R227ea, R245fa, R123 as circulating working fluid. Thermodynamic analysis of the IHE-OFC system is conducted, and the system is optimized with net power output as the optimization objective. The results show that when the heat source temperature is less than or equal to 160℃, the net power output of the R601 IHE-OFC system is maximal. When the heat source temperature is higher than or equal to 190℃，the net power output of the R601 traditional OFC system is maximal. When the heat source temperature is 170℃, the net power output of the R601a IHE-OFC system is maximal. When the heat source temperature is 180℃，the net power output of the R601a traditional OFC system is maximal. Moreover, there is a characteristic temperature for each working fluid, which is the sum of the temperature corresponding to 0.85P_cri and pinch point temperature difference of heater. Due to the influence of the characteristic temperature of the working fluid, the optimal flash pressure, IHE temperature rise on the low temperature side, and the system efficiency initially increases and then remains constant with increasing heat source temperature.

The isothermal lattice Boltzmann method two-phase flow model combined with the particle motion model was used to study the interaction between single particles and thin liquid film. The detailed process of liquid film rupture caused by a single spherical hydrophobic particle was visually shown through simulation. The whole process of the hydrophobic particles causing the rupture of the thin liquid film can be divided into two stages. Stage 1 is the stage in which the particle contacts the liquid film and moves to the inside of the liquid film under the action of the interfacial force until the particle just penetrates the liquid film. Stage 2 is the stage in which the upper and lower liquid surface are driven by the capillary force to move on the surface of the particle. It was found that hydrophobic particle with contact angle of 106.7° caused the shortest rupture time of liquid film. When the thickness of the liquid film is greater than the depth of the liquid immersed in the equilibrium of the particles at the vapor-liquid interface, the time of hydrophobic particle leading to the rupture of the liquid film will be greatly increased.

Hydrothermal pretreatment is one key process for efficient energy conversion of lignocellulose raw materials. However, the reaction path and reaction mechanism of hydrothermal pretreatment using wheat straw as raw materials are still insufficiently studied, limiting the optimization of the pretreatment process and the real-world application. In this paper, wheat straw was used as the research object, and the reaction kinetics of hydrothermal pretreatment of lignocellulose was experimentally studied. It was found that the degradation of hemicellulose to xylooligosaccharide, xylose, and furfural is the main degradation process in the hydrothermal pretreatment process. In addition, the concentration of xylooligosaccharide and xylose in the hydrolysate decreased with the increase of pretreatment temperature, while the concentration of furfural increased. The concentration of xylooligosaccharide and xylose in the hydrolysate first increased and then decreased with the incubation time, and the concentration of furfural tended to be stable with the incubation time. According to the experimental results, a new reaction path was proposed, and the kinetic rate constant and the activation energy of the reaction were obtained. The obtained kinetic model can well explain the changes in the concentration of the reactants, which was in a good agreement with the experimental data. This model can provide guidance for the design of wheat straw hydrolysis pretreatment system.

A series of Ba and Co doped MnO_x doping catalysts were prepared by citric acid complex method. The effects of Ba and Co doping on the performance of MnO_x low temperature NH₃-SCR were studied. The test results showed that the addition of Ba inhibited the catalytic performance of MnO_x. The Co addition promoted the catalytic performance of MnO_x. When Ba and Co are co-doped, the performance of the catalyst increased obviously. 3BaMnCoO_x showed the most excellent catalytic performance, and the catalytic activity was above 99% when the reaction temperature was higher than 180°C. It showed good water and sulfur resistance. The catalysts were characterized by XRD, SEM, NO-TPD, NH₃-TPD, H₂-TPR and NO adsorption in situ infrared spectroscopy. The results showed that MnCo₂O_4.5 solid solution was formed after Co doping, which guaranteed excellent redox performance. Ba doping provided a new NO adsorption site for the catalyst, which led to the formation of new active nitrate adsorption species. The NO adsorption performance of the catalyst was promoted. These characteristics make BaMnCoO_x low-temperature denitration catalysts show excellent denitration performance.

The kinetic parameters were obtained by adsorption isotherm, and the CFD model was established to simulate the adsorption process of hydrogen/nitrogen in the structured 5A molecular sieve adsorption bed. The effects of structural parameters such as the adsorbent sheet spacing and thickness and process parameters such as adsorption pressure and volume flow rate on the adsorption performance to the mixed gas were discussed. The results show that reducing sheet spacing and thickness are beneficial to the mass transfer coefficient and bed saturation degree. Increasing the adsorption pressure can improve the bed saturation degree, but will reduce the mass transfer coefficient. The effect of the flow rate on mass transfer coefficient is not obvious, but when the flow rate is high, both the adsorption capacity and the bed saturation degree decrease. The structured 5A molecular sieve adsorbent has good adsoption performance.

In order to solve the key technical problems such as similar boiling points of cyclohexanol distillation residues and the difficulty of separation by conventional separation methods, the 3-cyclohexylcyclohexene, 1-cyclohexylcyclohexene and dicyclohexylidene were reduced to cyclohexylcyclohexane by catalytic hydrogenation and the boiling point difference between the two components was enlarged. High purity cyclohexylcyclohexane and dicyclohexyl ether were obtained by vacuum distillation. Using Pd/C as catalyst, the optimum conditions for catalytic hydrogenation of 3-cyclohexylcyclohexene, 1-cyclohexylcyclohexene and dicyclohexylidene to cyclohexylcyclohexane in residual solution were obtained. The reaction temperature was 120℃, the reaction time was 4 h, the reaction pressure was 4 MPa, the stirring speed was 550 r/min, the amount of Pd/C catalyst was 0.4% of the mass of the material, the selectivity was more than 99.5% and the conversion rate of the materials was 98.7%. After vacuum distillation, the purity of cyclohexylcyclohexane and dicyclohexyl ether is more than 99.5%.

Coking heating furnace is the key plant in the delayed coking unit. Thermal efficiency is one of the most important key performance indications. In this work, the thermal efficiency dynamic model is established based on the first principles of heat transfer equations and heat balance conditions. A joint particle filtering method combined with Kalman filter and particle filter is proposed to correct the model prediction and the convergence of the proposed method has been analyzed. The application results confirmed the feasibility and effectiveness of the proposed method, and laid the foundation for the advanced control of the delayed coking unit.

To study the data mining theory method and experimental verification of the refrigerant leakage identification of the heat pump system, firstly establish an air source heat pump system refrigerant leakage test bench to test the experimental parameters of the heat pump system in normal working conditions, interference working conditions, and leakage working conditions. Then, principal component analysis (PCA) was used to process the experimental data, and support vector machine (SVM) was used to classify and identify the data. A leakage identification model based on PCA-SVM was established which verified in both two classification and multi classification model. The leakage rate and the influence of different fault conditions of the model was studied. RefliefF feature selection algorithm is used to screen the original feature parameters which simplify the feature parameters of the identification model. The results show that, for the air source heat pump water heater, the leakage identification model has a high identification of 100% in the leakage mode, and the slow leak diagnosis recognition performance of the weak in rapid leak, the same model in different fault diagnosis recognition performance is different, slight influence on the system s running fault diagnosis recognition performance is weaker than other malfunction. RefliefF feature selection method reduces the original 41 system characteristic parameters to 10 characteristic parameters. The identification accuracy of the leakage identification model after parameter screening and optimization is also maintained at a high level, the optimized leakage identification model is more conducive to practical application.

The components of microbial fermentation process are extremely complex. The physicochemical and biochemical reactions are mixed and overlapped. Many metabolic states cannot be measured directly. The hybrid cybernetic model combines the elementary mode analysis and the cybernetic model control. It not only involves both intracellular product information and metabolic behavior, but also introduces control variables to regulate the activity and synthesis of catalytic enzymes. Based on the kinetic equation of microbial metabolism, the real-time state monitoring of microbial metabolism could implement. In view of the fermentation process of poly-β-hydroxybutyrate, by means of the metabolic pathway analysis, the nonlinear dynamics of the existing hybrid cybernetic model is first linearized. Then the extended Kalman filter is used to estimate the metabolic state of fermentation process. Simulation results show that it has a good estimation effect on some important state variables in microbial metabolism.

Aiming at the non-linear and dynamic characteristics of intermittent process data, a process fault monitoring method based on recurrent autoencoder (RAE) is proposed. To establish monitoring model, an autoencoder is constructed by using long short-term memory (LSTM) recurrent neural network. Compared with the traditional autoencoder, the proposed method can effectively extract the dynamic correlation information between time series samples. Firstly, a three-step expansion method combining batch expansion and variable expansion are used to expand the batch process data into two dimensions, and input sequences for modeling is obtained by sliding window sampling. Then, LSTM is used to reconstruct the input sequences to train an autoencoder model. Moreover, the Squared prediction error (SPE) statistics are constructed based on reconstruction error to achieve on-line monitoring. Finally, the proposed method is applied to penicillin fermentation process for simulation experiment and recombinant Escherichia coli fermentation process monitoring. The results show that the method can detect faults in time and has better monitoring performance.

Because the process simulation model based on rare earth extraction mechanism does not consider the extraction efficiency of the extraction tank, it is difficult for the content of the components output by the model to meet the actual industrial conditions. Therefore, this paper combines the mechanism model with a data-driven method to establish the rare earth extraction process simulation which based on the correction of separation coefficient. Firstly, on the basis of the rare earth extraction process mechanism model with relative separation coefficient, the correction value of separation coefficient is introduced to expand the mechanism model of rare earth extraction. Secondly, the data-driven method and Fibonacci tree optimization algorithm(FTO) are used to optimize the correction value at all levels, and MATLAB GUI is used to develop the rare earth extraction process simulation system. Finally, according to the actual data of industrial field, the process of rare earth extraction is simulated and verified when the working condition is changed. The results show that the simulation of the process constructed in this paper conforms to the actual working conditions of the rare earth extraction process.

In the production of finished gasoline，octane number as the key indicators of quality of finished product gasoline and foundation of formula model，it is import to accurate measuring its content. However, due to the existing measurement technology and the constraints of complex conditions, it is difficult to obtain the component data effectively. Considering the problems of genetic algorithm (GA), particle swarm optimization (PSO), and optimizing back propagation (BP) network, a serial hybrid particle swarm genetic algorithm (serial hybrid PSO-GA, SHPSO-GA) is proposed to optimize the BP network, and it is used to predict and model the octane number. In this method, the output of PSO algorithm is divided into two populations according to the fitness value, and the bad ones are discarded and the good ones are retained. Then the optimized population was further optimized by GA crossover and mutation, the optimal population was applied to BP network parameter optimization. Finally, based on the method and the industrial historical data, a prediction model of octane number of hydrogenated gasoline was established. The simulation results showed that, compared with the traditional BP, GA-BP, PSO-BP, PSO-GA-BP and other methods, SHPSO-GA-BP had better prediction performance due to the deeper integration of PSO and GA, it could be used for octane number prediction.

Aiming at the control problem of nonlinear dynamic systems, a model predictive control (MPC) method based on adaptive fuzzy neural network (AFNN) was proposed. First, in the offline modeling phase, a rule automatic splitting technique is used to generate initial fuzzy rules, and an improved adaptive LM learning algorithm is adopted to optimize network parameters. Second, in the real-time control process, the network parameters of the AFNN are adjusted according to the error between the system output and the predicted output, so that providing an accurate prediction model for the MPC. Furthermore, the gradient descent optimization algorithm with adaptive learning rate is used to solve optimization problem and obtain the nonlinear control law online, which is applied to control the dynamic system. In addition, the convergence and stability analysis of the proposed AFNN-MPC are given to ensure its successful application in practical engineering. Finally, numerical simulation and two-CSTR process experiments are used to verify the effectiveness of AFNN-MPC algorithm. The results show that the proposed AFNN-MPC has superior control performance.

Using the density functional theory (DFT) of quantum chemistry, the adsorption and diffusion of the surface reaction precursor AlCH₃ (MMAl) on the AlN (0001) -Al surface covered with NH₂ and H during MOCVD growth of AlN were calculated and analyzed. By analyzing the surface adsorption energy, diffusion energy barrier, and Mulliken population, etc., the possible stable adsorption structure and diffusion path were determined.The study found that: on the AlN (0001) -Al surface covered with NH₂ and H, with the change of the coverage of NH₂ and H, MMA1 was stably adsorbed at the T4 and H3 positions with similar adsorption probability.As the proportion of NH₂ increases and the proportion of H decreases, MMAl transfers charges to the surface of AlN after adsorption, at the same time its adsorption becomes relatively easy, and diffusion becomes gradually difficult.Compared with before adsorption, the Al-C bond length in MMAl after adsorption is shortened, the bond energy is enhanced, and the detachment of CH₃ is not easy, resulting in a higher probability of introducing C impurities.It shows that MMA1 is not only one of the main reactive substances in growth, but also one of the main sources of introducing C impurities. If there is covering H on the AlN surface, the adsorbed MMA1 will cause the covered H atoms to tend to detach from the AlN surface, which is conducive to subsequent growth.

For aeroengine cylinder seals, the floating ring is often broken due to insufficient dynamic pressure, which causes the floating ring to rub against. Based on this, the Fluent software is used to simulate the flow field of two kinds of models, namely, the existing cylindrical grooved gas film and the spiral grooved gas film, and carry out with test verification. The results show that for the grooveless gas film model, increasing the eccentricity, rotation speed and pressure difference will increase the dynamic pressure effect of the seal. The increase of eccentricity and pressure difference will increase the leakage of the model, but the change of rotation speed has little effect on the leakage of the model; for spiral groove gas film seal, the increase of eccentricity, rotation speed and pressure difference will increase the buoyancy of the gas film. With the increase of eccentricity and pressure difference, the leakage of the model increases. Based on the above two conclusions, it can be concluded that the speed is the secondary factor affecting the leakage; the spiral groove model has better dynamic pressure effect and less leakage compared with the grooveless model, so it can reduce the friction of floating ring. Therefore, this study has important reference significance for the development of better cylindrical seal structure.

Boldenone, as an important anabolic androgenic steroid, has the function of improving muscle mass and endurance. The traditional synthesis method of boldenone is to synthesize from 1,4-androstenedione (ADD) by chemical method, but the process is complex and the pollution is serious. 17β-hydroxysteroid dehydrogenase (17β-HSD) can catalyze the redox reaction of C-17 site of steroids, and realize the conversion of ADD and boldenone. In this study, six different 17β-HSD genes were screened and heterologously expressed in E. coli. Using different recombinant strains to transform ADD to boldenone, the results showed that E. coli BL21/pET28a-HSDPy had the highest conversion rate of ADD, so BL21/pET28a-HSDPy was selected for further study. The enzymatic properties of the recombinant strain were identified and the whole cell transformation conditions were optimized. The results showed that under the condition of 36 g·L^-1 biomass and 5.40 g·L^-1 substrate concentration, 3.66 g·L^-1 boldenone was obtained after two batches of feeding, which was 4.1 times higher than before optimization. Moreover, no by-products were detected during biotransformation. This study provides the possibility for the biosynthesis of boldenone.

Cardboard, rubber, pine wood and nylon were selected as representatives of household wastes, and their pyrolysis characteristics were investigated through thermal gravimetric analysis under different heating rates (15, 40 and 200℃/min). Based on the characteristics of the weightlessness curve of each household garbage component, a finite parallel response model was established, and the corresponding dynamic parameters were calculated by particle swarm algorithm, and cross-validation was performed. The results indicated that the kinetic parameters obtained through PSO could not only accurately reproduce the complex peak distribution of the weight-loss curves, but also effectively predict the alteration of weight-loss characteristics under different heating rates.

Based on the Randles equivalent circuit, this paper studies the coupling relationship between operating temperature and humidity of proton exchange membrane fuel cell (PEMFC), establishes the direct current (DC) internal resistance and alternating current (AC) impedance characteristics of the stack, and studies the electrochemical impedance spectrum and U-I output characteristics under different operating conditions. The AC impedance method and the U-I characteristic method are combined to obtain the correspondence between the AC impedance and the DC internal resistance under different water management states, and the influence of the water management state on the output performance of the stack is analyzed. The simulation and experimental results show that the different water management states have consistent variation rules and corresponding quantitative relationships in the AC impedance spectrum and the U-I characteristic curve. The phenomenon of membrane dryness, flooding, etc. in the output performance of the stack is in the DC internal resistance. And the change of the AC impedance map has clear performance characteristics. By studying the impact of water management states on both, it is possible to optimize the operating conditions and optimize the output performance of the stack.

Accurate prediction of acid dew point(ADP) and acid condensation is the key to deeply reduce the flue gas temperature and to ensure the safe and efficient operation of the heat exchange equipment in coal-fired power plants. The ash particles in the flue gas have great influence on the occurrence of ADP and acid condensation droplets. The iterative calculation method of ADP and acid condensation considering the effect of fly ash particle radius on local condensation mass transfer were proposed for the first time in this paper. When the fine ash particles radiuses are smaller than the critical radius (r_ash<r₀), with the reduction of fine ash particle radius, the condensation rate around fine ash particles, especially acid condensation rate, is markedly increased at ADP. And the acid condensation is easier to occur with the smaller ash particle radius. However, when the supercooling degree exceeds 30℃, the effect of ultrafine ash particles on the acid condensation of heating surface can be ignored. The amount of acid solution condensed around fine fly ash particles, which can not be caught on the heating surface, is small, and the reduction effect of the fly ash particles on the acid vapor of flue gas can be negligible. The theoretical calculation method in this paper provides a theoretical basis for the analysis of acid-ash fouling layer on the field experiments, and useful guiding significance for the safe and efficient operation of the heat exchange equipment in the coal-fired boiler.

In order to make the duo-temperature R744 supermarket refrigeration system operate at maximum efficiency in any ambient temperature, a multi-ejector circuit (including gas-gas ejector and gas-liquid ejector) is added to the R744 parallel compression refrigeration system to ensure that the system can still operate at higher efficiency in high ambient temperature, and automatically switch between parallel compression refrigeration mode and boost refrigeration with multi-ejector mode with the change of ambient temperature. The thermodynamic model of the system is established. The calculation results show that when the ambient temperature is lower than 17.32℃, the parallel compression refrigeration system mode is adopted; when the ambient temperature is higher than 17.32℃, the transcritical boost refrigeration system with multi-ejector mode is adopted. When the ambient temperature changes from 21.1℃ to 36℃, the COP of the multi-ejector refrigeration system is 15.91%—32.61% higher than that of the parallel refrigeration system.

Cotton threads are employed as flow channels in thread-based microfluidic fuel cells, which eliminates external pumps and benefits for miniaturization, showing a promising power source for portable microfluidic devices. However, the cell performance is limited by the fuel transfer at the anode. To better understand the fuel transfer characteristics coupled with electrochemical reaction at the anode, lattice Boltzmann (LB) method was used for the cotton thread-based microfluidic fuel cell. A three-dimensional numerical model of the cotton thread flow channel was developed and the distributions of velocity and concentration of fuel were calculated. The effects of inlet fuel concentration and flow rate on performance and mass transfer characteristics of anode were also discussed. The results show that LB results agree well with experimental results of the anode polarization curve. The velocity of fuel inside the cotton thread is lower than that in the gaps among threads. The fuel concentration decreases along the flow direction under different anodic over potentials and larger decrement is found at higher anodic over potentials. An increasing average current density is obtained with an increase in the inlet fuel concentration, leading to a better anode performance. Moreover, with an increase in the inlet fuel flow rate, a greater difference in the fuel concentration is observed between the location where the cotton thread contacts with reaction interface and other regions. When the inlet flow is low, the difference in concentration is small and the concentration in the rear part of the flow channel is low.

Removal of organic dyes in water by adsorption-photocatalysis technology is one of the efficient and energy-saving methods. However, in the process of photocatalytic degradation of pollutants by carbon-based sorbents, gradual oxidation of carbon-based adsorbents occurs due to active oxygen attack. In this study, titanium dioxide/layered double hydroxide (TiO₂/LDH) non-carbon-based composites are synthesized using the urea hydrolysis hydrothermal method. They not only have high adsorption capacity for organic dyes in water, but also are capable to regenerate themselves by light irradiation. Their adsorption capacity for methyl orange is 527.5 mg/g, which regenerate percentage is up to 88.6% after 4 cycles. In addition, their adsorption capacity for methylene blue is 208.3 mg/g, which regenerate percentage is up to 94.7% after 4 cycles. During the adsorption-photocatalytic regeneration process, the LDH substrate itself has strong oxidation resistance and high adsorption capacity. Moreover, LDH improves light absorption efficiency of the loading agent TiO₂. It provides a feasible strategy for the removal of organic pollutants in water and optimization of adsorption-photocatalytic composite materials.

Agricultural straw usually contains high alkali metals, which can easily cause high temperature melting and sintering of the boiler during the combustion process and affect the normal operation of the boiler. In this work, the effect of a phosphate additive, Ca(H₂PO₄)·H₂O (calcium phosphate monobasic, CPM), on ash sintering characteristic of a typical agricultural biomass cornstalks was investigated by using standard ash fusion measurement and ash sintering test at 700—1000℃. Meanwhile, the reaction behavior and the possible reaction products from the calcination of calcium phosphate monobasic and potassium salts at elevated temperature were investigated. The results showed that, during the heat treatment at elevated temperatures, temperature and mixing ratios of CPM and potassium salts had significant influence on reaction products. Meanwhile, when the mixture of CPM is excessive, in addition to the two reactions, there is high temperature decomposition reaction of CPM and secondary reaction between the reaction products. The reaction of CPM and potassium salts started at 300℃, with mainly Ca₂P₂O₇, Ca(PO₃)₂, KCa(PO₃)₃ at 300—600℃ and mainly K₂CaP₂O₇ at 700—900℃. Thermal decomposition of CPM and secondary reactions between the resultant products occurred when the P/K molar ratio was larger than 1, in addition to the reaction between CPM and K salts. In addition, it was found that K₂CO₃ has a higher reactivity with CPM compared to KCl. The addition of CPM in cornstalk significantly increased the ash fusion temperature and reduced the sintering degree by forming high melting phosphates mainly Ca₉MgK(PO₄)₇ and CaKPO₄. These results can provide theoretical guidance for the application of phosphorus-based additives in alleviating ash fusion and sintering issues during agricultural biomass combustion.

Aiming at the surface characteristics and properties of quartz sand (OQS), surface morphology reconstruction and surface coating modification were performed. According to the coating modification difference, hydrophilic modified sand (IMS), hydrophobic modified sand (OMS), cationic modified sand (CMS) and amino modified sand (AMS) were prepared. The laboratory simulated secondary treatment effluent was taken as the research object, and the biological sand filtration process centering on 6 kinds of quartz sand [4 kinds of composite modified sand, surface reconstituted sand (control 1), and original sand (control 2)] was investigated. The reduction effect of carbon, nitrogen, phosphorus and sudden pharmacologically active substances (PhACs), the microbial population structure of each group of bio-sand filters was analyzed, and ecological risk assessment was performed. The results show that the removal rate of conventional pollutants by various processes is between 24.22%—90.35%, and the removal effect of CM-BSF on conventional pollutants is the best; 6 types of biological sand filtration processes remove 12 types in 5 categories of PhACs. The rate is between 7.9%—50.3%, and the removal effect of CM-BSF by modified sand filtration process is better. High-throughput testing shows that the microbial species in each group are highly similar, but the abundance is different. Generally speaking, it has PhACs degradation ability. The abundance of the functional bacteria in the composite modified quartz sand-covered biological samples is relatively high. According to the analysis of the ecological risk assessment method, the ecological risk of effluent from the CM-BSF process is the lowest.

Wax appearance temperature (WAT) is an important parameter of petroleum fluids. Obtaining accurate wax appearance temperature is a prerequisite for ensuring the safe transportation of waxy crude oil pipelines. New measurement methods were proposed in this study, including temperature scanning method using near infrared spectroscopy (NIRS) and refractive index (RI) method. Furthermore, wavelength scanning method using NIRS was improved in its testing and data analysis process. In addition, these methods were compared with two commonly used ones, polarizing microscopy (PM) and differential scanning calorimetry (DSC). The results showed that reliable WAT results could be obtained by NIRS and RI methods with high sensitivity and stability. The measurement results were less susceptible to the simple testing and analysis process, especially suitable for volatile samples. Moreover, the stirring in the testing process of NIRS methods effectively reduced the influence of supercooling degree, while it was still different from the flowing condition in real pipelines.

A ZSM-5 zeolite membrane was hydrothermally synthesized using a template-free method for bio-oil pervaporation dehydration. The ZSM-5 zeolite membrane showed both excellent chemical stability and selectivity in the highly acidic and multi-component bio-oil system. However, the membrane encountered serious membrane fouling in bio-oil during pervaporation, which resulted in a significant loss in the permeation flux. The membrane regeneration test showed that the permeation flux increased with increasing the regeneration temperature, and the value could be recovered to 88% of the original flux of the fresh ZMS-5 membrane after the membrane was regenerated at 220℃. The membrane regeneration mechanism showed that the intracrystalline pores of the ZSM-5 zeolite membrane were easily fouled in the bio-oil system, which was responsible for the rapid decrease of the permeation flux; while the intercrystalline pores with a relatively larger pore size were difficult to be completely blocked, thus the intercrystalline pores functioned as the main channels for water permeation through the fouled ZSM-5 zeolite membrane. The above results indicate that the bio-oil pervaporation, dehydration performance of a ZSM-5 zeolite membrane can be effectively improved by properly adjusting the number and size of intercrystalline pores of ZSM-5 zeolite membranes.

A new type of composite adsorbent based on activated alumina(AA) and CaCl₂ as a hygroscopic salt was developed. It can be used in thermochemical adsorption heat storage systems with water as the adsorbent, and its internal structure, adsorption performance and heat storage performance were studied. Samples with different salt contents were fabricated to store low-temperature thermal heat by impregnation methods. Morphologies records, sorption kinetics and thermal energy storage performance of AA/CaCl₂ composite sorbent were investigated. The maximum salt content of the solution leakage phenomenon was determined. Sorption kinetics and equilibrium sorption capacity under conditions of 30℃ and multi relative humidity were studied by utilizing constant temperature and humidity chamber. Influence of salt content and relative humidity on the sorption performance of AA/CaCl₂ composite sorbent was studied. Results showed sorption capacity of AA/CaCl₂ composite sorbent increased with increasing salt content and relative humidity. The specific surface area and pore volume were measured by automatic specific surface area and porosity analyzer. Energy storage density was measured by simultaneous thermal analyzer. The sample with highest salt content had the best energy storage performance with 0.51 kW·h/kg mass energy storage density and 610.2 kW·h/m³ volumetric energy storage density. As a consequence, AA/CaCl₂ composite sorbent is promising sorbent in field of chemisorption thermal energy storage.

To improve the melting performance of paraffin (PA) during the phase change energy storage process, a small amount of expanded graphite (EG) was added to the PA to prepare four kinds of paraffin/expanded graphite composite phase change materials (PA-EG). The PA-EG with suitable proportion was screened out by thermophysics analysis, with melting process of PA-EG and PA in the horizontal shell and tube latent heat thermal energy storage unit being experimentally studied. Based on the changes in the temperature field of the phase change material and the weighted melting fractions calculated, the melting performance between PA and PA-EG was compared. Also, the effect of the heating temperature on the melting performance was explored. The results indicated that the thermal conductivity of PA-EG3 was 7 times higher than that of PA, while the phase transition temperature and latent heat remained relatively identical. The natural convection effect of PA-EG3 during melting was weaker than that of PA. However, higher thermal conductivity resulted from added EG could significantly improve the melting of middle and lower parts in the latent heat thermal energy storage unit, making its overall melting rate higher than that of pure PA. When the heating temperature was 80℃, the melting process of PA-EG3 is 78.16% shorter than that of PA. In addition, reduced heating temperature can significantly increase the complete melting time of PA and PA-EG3, with smaller increment for PA-EG3 under the same condition.

The vaulted oil tank fails to explode after being roasted by external flames, which may cause serious casualties and huge economic losses. To warn the failure and explosion of vaulted oil tank under fire condition, through the high temperature material mechanical performance experiment platform, the weak connection structure of the vaulted oil tank is tested for destruction. The breaking force and stress values of weak connection structure failure under different fire temperature conditions are obtained. The results show that when the temperature is higher than 300℃, the values of pulling force and failure stress change significantly, of which 450℃ is the peak temperature. Furthermore, the failure pressure of 1 m³ vaulted oil tank under different temperature conditions was tested by establishing failure test platform for small-sized vaulted oil tank. The comparison between the calculated and experimental results shows the accuracy of the failure pressure of 1 m³ vaulted oil tank. On this basis, the failure pressure calculation model of vaulted oil tank was constructed, and the failure pressure of vaulted oil tank with different volume under different fire temperature was deduced. The results can be used as the criterion for the failure of vaulted oil tank to provide data support for the explosion warning for vaulted oil tank.

To study the influence of the initial fuel temperature of the transformer oil on the combustion characteristics, an oil pool fire combustion test platform was set up, and pool fire experiments with different initial fuel temperatures and different oil pool diameters were conducted. The whole burning process, burning rate and boiling layer thickness were measured and discussed with the variation of initial fuel temperature. The results show that the whole burning process can be divided into three stages: (1) initial development stage; (2) steady burning stage; (3) extinguishment. The burning rate shows an increasing trend with the increase of initial fuel temperature at the initial development stage. This is because the heat used to increase the fuel temperature will decrease with the increase of initial temperature. At the steady burning stage, although the burning rate will increase with the initial fuel temperature increasing, the increasing rate is slow and can be nearly neglected. In the experiments, the burning rate is increasing obviously with the increase of burning size. In addition, the boiling layer thickness is around 2.17 mm, independent of the initial fuel temperature at the steady burning, except the tests with a diameter of 20 cm. Therefore, it is necessary to improve the fire extinguishing efficiency to respond the initial fire development and build some barriers to avoid the leakage fuel spread.