Polystyrene can be fractionated with supercritical propane.The main advantage of supercritical fluid fractionation is that large polymer fractions with a narrow molecular mass distribution can be obtained without using hazardous organic solvent.Isothermal fractionation was performed using increasing pressure profiling that provided milligram-size fractions with M_w distribution of 1.0—2.0 as compared to parent polymer with polydispersity 4.225.At the same time,isobaric fractionation was performed using increasing temperature profiling that provided fractions with M_w distribution of 1.3—2.0 from the same parent polymer.The molecular mass of fraction increases with increasing operating pressure and temperature as the solvent power of SCF increases.The major benefit of SCF solvent relative to a liquid solvent is that the solvent power of SCF can be finely tuned by controlling operating conditions.It is recommended that pressure should be controlled to tune the solvent power of SCF effectively.With a SCF solvent, the solubility of a polymer drops to essentially zero if the pressure is reduced to near ambient condition,thus facilitating the recovery of a solvent-free polymer fraction.
A model relating the molecular mass of fraction to operating variables was deduced on the basis of the theory of polymer solution.The model parameters were estimated by using experimental data.The average relative deviation was below 18%.

The relationship of the stability period of supersaturated silica with temperature, alumina concentration, alkali concentration and supersaturation was obtained under the hydrolysis condition. Furthermore, according to the kinetics theory of crystallized nucleation, the equation to calculate the supersolubility of silica in sodium aluminate solution was deduced as well, which correlated the supersolubility of silica with the stability period of supersaturated solute in solution.The mechanism of nucleation was also investigated through classical nucleation theory. Under the hydrolysis condition in alumina production, the nucleation mechanism was mainly heterogeneous.

Based on the flow characteristics and a structural characteristics of a heat exchanger with longitudinal flow of shell-side(HELFS),simplified physical model of HELFS is presented.The mathematical model is set up on the basis of the governing equations of viscous hydromechanics.By adopting the operator splitting algorithms,the Galerkin finite element method is used to deduce the discrete equations.In order to verify the calculated fluid flow field of HELFS, the Laser Doppler Velocimetry (LDV) is used to measure the local fluid velocity values on seven sections of shell-side of HELFS.The calculation result is in good agreement with experimental data, with error of 7%—20%.It is feasible to do numerical simulation by separating HELFS into heat import section,cyclic development section and export section.The theory and procedure of numerical calculation are correct in number value.

In the present work, the process of steam-jet ejector was analyzed in detail.Three thermodynamic models for calculating entrainment ratio of steam-jet ejector:the ideal model, the momentum conservation model and the kinetic energy conservation model were deduced according to the change in thermodynamic state.The IAPWS-IF97 formulation was used to compute steam properties,and the effects of nozzle, mixing and diffuser efficiency on ejector performance were studied.Although there was some difference between the MC model and the ideal model when no imperfect factors were considered, however, it was found that the MC model represents the empirical curves better than the KEC model if reasonable efficiencies were used.

In this paper, the dynamic characteristics of a continuous adsorption refrigeration system driven by intermittent heat source are studied by means of experiments. The variation regulations of the operating parameters are obtained. Meanwhile the dynamic characteristics of the system with a heat accumulator are compared with that without a heat accumulator in the working condition with intermittent heat source. The influences of heat source cut-off time are analyzed and the role of heat accumulator during the heat source cut-off is discussed. From the results, a heat accumulator is found to be one of best devices to alleviate the bad influence of intermittent heat source on an adsorption refrigeration system.

The macro-scale pseudo-particle model(MaPPM)is an effective method used in high resolution simulation of particle-fluid systems, which can be implemented with an algorithm similar to molecular dynamics (MD) simulation.However, the wide application of MaPPM is only possible with the advent of high-performance parallel computers.The great size gap between solid particle and pseudo-particle makes MaPPM different from MD simulations during the parallelization process, which is the specialty and difficulty in this paper.The domain decomposition method is used in the parallel algorithm because of the great number of pseudo-particles in particle-fluid systems. The algorithm is also improved according to the specialty in MaPPM to reduce computation cost. The computation is conducted on COW (cluster of workstations) with different system sizes and various numbers of processors to test its performance. Computation results indicate that the new algorithm has high parallel efficiency and good scalability. The parallel implementation will help to make use of MaPPM in large-scale simulations of two-phase flow.

The effects of superficial gas velocity,filter media flow rate and dust content in gas on collection efficiency of the cross-flow moving granular bed filter were investigated experimentally and the effect of dust deposition in the granular bed was also discussed. The results showed that a lower superficial gas velocity and moving speed of pellets could improve collection efficiency. The deposition of dust in the granular bed could affect dust removal efficiency. Less dust deposit could improve the efficiency obviously,while such improvement could become insignificant due to reentrainment of the deposited particles. A mathematical model was established to simulate the effect of dust deposit on collecting efficiency and the non-uniform deposition of dust in the granular bed on the basis of the constricted-tube concept. The model test showed that the model prediction was in good agreement with the experimental data for operating gas velocity from 0.1 m•s^-1 to 0.3 m•s^-1.Based on the model, the analysis on the relationship of collection efficiency with the length of the granular bed and the distribution of dust deposit was conducted.

The influences of surfactant on the pressure drop in horizontal two-phase flow was investigated experimentally. Air/water and air/100 mg•kg^-1 sodium dodecyl sulphate (with 95% purity grade) aqueous solution were used as working fluids. The results presented a demonstration that the drag reductions depended on flow regimes. Drag reductions up to 83.3% for stratified flow, 83.2% for plug and slug flows and 31.2% for annular flow were observed in the experiment. The drag reduction was caused either by adding the surfactant itself or by the shift of flow regime due to the addition of surfactant.

Coalescence process of two fluid particles is very complicated. This paper tries to integrate the approaching process of two fluid particles and the draining process of the intervening liquid film between two particles, by using the assumption of plane film and taking into consideration the change of the radius of plane film and the interaction force between two fluid particles with time. Thus, an integrated model for the minimum thickness of the intervening liquid film between two contacting fluid particles is developed.The effects of size ratio, initial relative velocity, interface tension and viscosity of continuous phase on minimum film thickness are discussed based on the integrated model. The comparison between the model calculation and the data from Scheele and Leng shows that this model is reasonable.The Stefan-Reynolds equation is only fit for draining of plane film which has been formed already, so its time coordinate is not identical to that of the contact interaction plane film model.Accordingly a time difference should be allowed for in advance in this model.

Predispersed solvent extraction( PDSE ) is a new method for separating solutes from aqueous solution by solvent extraction showing promise for efficient and quick extraction from extremely dilute solution.The use of colloidal liquid aphrons in predispersed solvent extraction may ameliorate the problems such as emulsion formation, reduction of interfacial mass transfer and low interfacial mass transfer areas in solvent extraction process.In the present work, colloidal liquid aphrons were successfully generated by using kerosene as a solvent, tributyl phosphate(TBP) as an extractant, sodium dodecyl benzene sulphate(SDBS) as a surfactant in aqueous phase and Tween-80 in oil phase. Colloidal gas aphrons were generated by using hexadecyltrimethyl ammonium bromide(HTAB). Extraction of phenol from dilute solution was studied by using colloidal liquid aphrons and colloidal gas aphrons in a semi-batch extraction column.The effect of pH, surfactant concentration, phase volume ratio on the extraction efficiency of PDSE process was studied.Calculations of mass transfer coefficients of both CLA and conventional liquid droplets revealed that CLA has much higher mass transfer coefficient of the dispersed phase.The PDSE process has a great advantage over traditional single-stage extraction process in K_da.

This paper firstly introduces the structure and characteristics of B-spline-based neural network, and then presents a new approach to modeling and control of molecular mass distribution for polymerization. Utilizing the nonlinear mapping of B-spline functions and iterative minimum least square algorithm, the model of MWD in polymerization process has been built. Based on the MWD estimated by the neural network model and optimal performance index, the control sequences are synthesized in order to make MWD close to the target distribution. Taking a pilot scale rig, in which bulk polymerization of styrene takes place, as a simulated object, the modeling and control procedures are studied and implemented, and the feasibility of the approach is established.

Commercial polysulfone membrane with negative surface charge was modified by low temperature plasma to initiate graft polymerization of 2-[DK](dimethylamino)ethyl methacrylate (DMAEMA), introducing positive charge onto HT membrane surface.It was confirmed by the XPS results that the introducing of positive charge group.Surface charge of the membrane was determined by measuring electroosmotic flux across the membrane.The effects of operation parameters including treatment power, treatment time, and polymerization time on the modification process were examined.The results also showed that surface modification by low temperature plasma, as described in the present paper, effectively reduced the net negative charge of membrane surface, and moreover, the adsorption of lysozyme on the membrane surface.

The close interval pipe-to-soil potential survey(CIPS)and the galvanostatic transient response method were used to detect the coating quality of buried pipelines.An algorithm was presented based on the dyadic wavelet transform for detecting the pipeline coating damage point with the ON and instant OFF CIPS potential and the difference between them.A six-layer wavelet Kohonen neural network model was set up to diagnosis the quality of pipeline coating with the galvanostatic transient response.The first to fifith layers of the model were used to pick up the information, and the last layer of the model was capable of self-training.The coating quality could be diagnosed quickly after the galvanostatic transient response was input to the model. The detection result of pipeline between Dagang and Cangzhou of Tianjin Dagang oil field was satisfactory.

The highly active Ti/nano-TiO₂-Pt modified electrode was prepared by using the method of electrochemistry synthesis and electro-deposition. The cyclic voltammetry was adopted to study and compare the electrochemical properties of the TiO₂/nano membrane electrode, single Pt electrode, Ti/nano-TiO₂-Pt modified electrode in H₂SO₄ solution.The electro-catalysis properties of Ti/nano-TiO₂-Pt modified was also studied in the process of Mn²⁺ oxidized to Mn³⁺. Results showed that Ti/nano-Pt modified electrode had high catalystic activity to Mn²⁺ and oxidation beak potential of Mn²⁺ was 1.28 V(vs. SCE), which is 0.12 V of negative-transfering as compared with that of single Pt electrode.The oxygen-releasing potential was 1.4 V,about 0.08 V higher than that of single Pt electrode. The electro-catalysis properties of Ti/nano-TiO₂-Pt modified electrode were better than those of single Pt electrode and Ti/nano electrode, while the efficiency of non-homogenous electrolysis oxidation was over 90%. The Mn³⁺ propared by electrolysis could oxidize glycerol to glyceraldehyde,and the yield was 96%.

The Burkholderia cepecia 1003 screened by the authors’ laboratory, which contains hydantoinase and N-carbamoylase activities, was used to prepare D-phenylalanine on a large scale. The dynamic parameters of the whole bioconversion process were measured, and the results showed that k_r was 3.975×10^-3min^-1,K_m and r_m of hydantoinase and N-carbamoylase were 16.7894 mmol•L^-1, 0.82688 mmol•L^-1, 0.6127 mmol•L^-1•min^-1 and 4.828×10^-4mmol•L^-1•min^-1，respectively.Simulation was made including processes of dissolution, racemization, hydrolysis of D-BH and hydrolysis of N-carbamyl phenylalanine.The significance of parameters in this model was investigated and these parameters were optimized. The result showed that the reaction rate of D-BH hydrolysis was higher than that of N-carbamyl phenylalanine hydrolysis,the latter was the limiting step of the whole process. Promotion of N-carbamoylase activity was helpful to D-phenylalanine production. Another result was that the rate of L-BH racemization was the main factor, which influenced the conversion of racemic BH.

The experimental conditions, including temperature, pH, denatured protein concentration and urea concentration, in the renaturation process of recombinant human interferon-γ inclusion body by dilution were studied and at the same time pulse renaturation was tested. The optimum renaturation conditions were obtained. Results showed that urea could suppress the aggregation of protein during the renaturation process and the suitable urea concentration increased with the increase of denatured protein concentration. The activity and specific bioactivity was up to 2.39×10⁵ IU•ml^-1 and 2.21×10⁷ IU•mg^-1 respectively under 4 ℃, pH 8.0, 1.0 mol•L^-1 urea, 0.1 mg•ml^-1 protein and pulse renaturation operation mode.

In this work 168 samples of CWM were prepared from 14 kinds of Chinese coals and 12 dispersants, and the apparent viscosities of these CWM were measured by Haake RV 12 model Rheogeniometer at shear rate D=100 s^-1.Slurries formulated with different dispersants for the same coal or with the same dispersant for different kinds of coal showed obviously different results in the dispersibility and viscosity reduction. The relationship between relative apparent viscosity of CWM and volume fraction of coal in CWM was studied. The result showed that the experiential constant (k) in the Frankel equation was not only dependent on the geometrical distribution of particles but also on the coal properties, and an experimential relationship between constant (k) and coal properties was set up. Furthermore, the effect of interaction of complex coal particles on the apparent viscosity of CWM was discussed.

Testing samples of super fine pulverized coal and common pulverized coal were made from Heshan coal.Contrast test of combustion characteristics, NO_x and SO₂ emission property, air staging combustion of super fine pulverized coal and common pulverized coal were carried out in a tunnel furnace with a single parallel flow burner. Experimental investigation proved that super fine pulverized coal has many advantages over common pulverized coal during combustion process, such as lower ignition temperature, better combustion stability, higher combustion efficiency, lower NOx emission,efficient sulfur removal,etc.

Four strains with rapeseed oil degrading power were isolated from contaminated soil and screened.Experimental results indicated that these four strains had different degrading activities and Pseudomonas sp.Z1 showed higher rapeseed oil degrading activity.Optimum condition of growth of Z1:30 ℃,pH 7.0,inoculum amount 1%,and shaker rotary speed 210 r•min^-1.Biodegradation of oily smoke was investigated at superficial velocity of biofilter reactor 0.3—1.2 cm•s^-1,retention time 10—40s and the effects of such factors as smoke concentration,flow rate and humidity on oily smoke removal were studied.The biofilter reactor was effective in removing oily smoke and was able to handle a high smoke load.

In this work, a fully coupled fluid flow and heat transfer model was developed to analyze molten aluminum infiltration with transient solidification and remelting through a fibrous preform in a centrifugal force field. The pressure, temperature and velocity distribution in the preform and the solid volume fraction profiles were presented for different conditions. The results show that the fibrous volume fraction and the rotational speed of equipment were very influential on transient solidification and remelting in the centrifugal force field. The length of solidification zone and its solidification rate increased with the advance of infiltration interface.An increase of rotational speed and porosity resulted in an increase of composite temperature, and a decrease of the solid volume fraction, as well as the length of solidification zone during the centrifugal casting process.

The surface modification of industrial SiC powders was carried out by polyethyleneimine(PEI), and the effects of pH and adding content of PEI on flow characteristics of the powder before and after modified treatment were analyzed. The results were:when pH of PEI is 6.5 and the mass fraction of PEI is 3%, the modified SiC powder possessed better flow characteristics, more saturation adsorption on the powder surface, more dispersive and uniform particle size distribution and shape.

A static equilibrium apparatus was built for determining solid solubility in supercritical fluid. Solubilities of polystyrene in supercritical propane were determined by the static equilibrium method at temperature from 383.15 K to 408.15 K and pressure from 10.0 MPa to 35.0 MPa. The effects of temperature and pressure on the solubility of polystyrene were investigated. The results showed that the solubility of polystyrene in supercritical propane increased with the increase of temperature and pressure. It was also shown that retrograde area could not exist within the temperature and pressure range. Furthermore, the solubility data of polystyrene in supercritical propane were correlated with the fairly good accuracy by a solution model presented in literature. The average absolute relative deviation (AARD) was 4.93%.

The performance of sheet metal structured packing Mellapak 350Y in a pilot-scale high-pressure column(0.15 m I.D.) was investigated at 700—1900 kPa. The packing height was 2.0 m. Isobutane and n-butane was used as test mixture. The imperfect flow phenomena in column, such as maldistribution, wall flow, end effect and backmixing could be revealed by testing the composition profile along the packing. A concave or convex composition profile curve might be a result of maldistribution,and f_max, which was the maximum value of liquid maldistribution friction could be used to judge the sensitivity to maldistribution of a proposed packed bed. Through comparing the separation efficiency at the top section of packing with that at the bottom section would disclose the existence of wall flow and end effect in the column. Moreover, the extent of gas and liquid backmixing in packing could be estimated if the composition profile along the whole column could be obtained.

Anthraquinone working solutions used in hydrogen peroxide manufacture were selected as the test system to investigate the flow pattern transition behavior of foaming system in the trickle bed reactor (TBR) with the method of measurement and analysis of the instantaneous pressure drop fluctuations. The boundaries and the corresponding flow map for the foaming system were established for TBR packed with different size particles. It was found that the size of particles shows significant effect on the flow regime distributions. A theoretical model proposed by Cheng and Yuan and an empirical correlation by Bartelmus and Janecki were used to predict boundaries of the flow pattern transition for anthraquinone working solutions. Comparison between estimation and experimental results showed that the predicted boundaries of Cheng and Yuan theoretical model are consistent with the observations in the present work.

Kinetic energy efficiency of atomizing air,by C is the ratio of the effective energy required for atomization to the kinetic energy of the atomizing air.The present study analyzes the variation of C with the Reynolds number of atomazing air stream, Ohnesorge number and air to liquid mass ratio. Atomization of non-Newtonian fluids with viscosity up to 4.4Pa•s is carried out by using a specially designed prefilming airblast atomizer. Drop sizes are measured by using laser diffraction technique. For liquids with low viscosities, impingement of air stream on the liquid film dominates the atomization process and film thickness exercises only minor influence on C; while for liquids with high viscosities, disintegration of liquid film is made by the impingement of air stream on the liquid film and the wavy movement of film,and C is higher for thinner liquid film in the same operation conditions.The shear force on the surface of liquid film formed by swirling atomizing air plays an important role in the atomization of film in the conditions of low air velocities and low liquid viscosities and its influence on atomization gradually weakens with increasing atomizing air velocity and liquid viscosity.Eventually impinging on the liquid film dominates the atomization process.

The onset of Rayleigh-Benard convection in a fluid layer dispersed with phase-change-material particles was studied numerically by using the linear stability theory.The dimensionless fluctuation of specific heat Q with dimensionless temperature T was given as a form of sine-function Q=1+bsin(ψT).Two kinds of numerical methods were used separately in the calculation of critical Rayleigh number Ra_cr and wave number k_cr.One was the numerical integration method using Simpson 1/3 rule, and the other was the numerical difference method of Runge-Kutta with Newton-Raphson iteration. Both methods showed the same calculation results that the critical Rayleigh number Ra_cr decreased monotonically with increase in the amplitude b of the sine-function, however, the critical wave number kcr did not show much difference with the amplitude b of the sine-function while ψ=π/2, but exponentially increased while ψ=π.

Machine learning techniques are finding more and more applications in the field of load forecasting. A novel regression technique, called support vector machine (SVM), based on the statistical learning theory is applied in this paper for the prediction of natural gas demands. Least squares support vector machine (LS-SVM) is a kind of SVM that has different cost function with respect to SVM. SVM is based on the principle of structure risk minimization as opposed to the principle of empirical risk minimization supported by conventional regression techniques. The prediction result shows that the prediction accuracy of SVM is better than that of neural network. Thus, SVM appears to be a very promising prediction tool. The software package NGPSLF based on SVM prediction has been put into practical business application.

Effect of some solid polymer electrolyte membranes,Nafion,Gore and Fuma membrane,on the electro-generative hydrogenation behavior of the PEMFC reactor was studied.Nafion membrane has demonstrated much better performance for the electro-generative hydrogenation of organic acids and enols than Gore and Fuma membrane.For Nafion membrane,the thickness and strength both influence the hydrogenation of organic acids and enols.

A modified subcell approach was used to measure the current density distribution of proton exchange membrane fuel cell (PEMFC) with straight channels flow field. For PEMFC with parallel channels flow field, subcells in inlet channels presented higher performance than those in middle channels, but showed lower performance than those in outlet channels. The experimental results with parallel channels flow field demonstrated that the current density distribution over the whole electrode was heterogeneous and was consistent with the velocity distribution from the mathematic model. Gas flow rate was one of prime factors to influence the current distribution of PEMFC cathode. With the decrease of reactant flow rate, the flooding process began at the flow field outlet region of a cell, and then propagated to the inlet area.

The direct synthesis of methylchlorosilanes by reacting metallic silicon with methyl chloride in the presence of a copper catalyst yields low-boiling component, high-boiling component and methyltrichlorosilane as by-products. The proposed process for prepares monosilanes from the HBC fraction by reacting it with hydrogen chloride in the presence of an amine or amide catalyst. The conversion of disilanes into monosilanes is above 80% in general and the best is 86%.A method is also proposed for preparing dimethyldichlorosilane from methyltrichlorosilane, reacting simultaneously with the LBC components having a high content of methyl groups and with the HBC non-cleavable components, in the presence of a catalyst, in which the best conversion is 66.2%,and the best content of dimethyldichlorosilane in final products is 46.4%.

The conditions of crystallization of micaceous iron oxide (MIO) were studied through the synthesis of MIO from precursor Fe(OH)₃ formed during oxidization of FeSO₄•7H₂O with H₂O₂. The experimental results showed that the concentration of NaOH as a hydrothermal medium had a strong effect on the formation, morphology, color and luster of crystal. The red iron oxide, yellow iron oxide and MIO with various types of crystal could be produced in the range of 0.019—14 mol•L^-1 of NaOH concentration with the reaction temperature equating to 433 K or above. The color of MIO crystal produced varied from reddish brown, brown to steel grey with increasing NaOH concentration.The reaction temperature also affected the formation, morphology, color and luster of crystal. There was a great difference in conversion time from precursor Fe(OH)₃ to MIO because of the changes of both NaOH concentration and reaction temperature. It was an effective method to age the crystal for a certain length of time to get more thinner MIO. The preferred technology parameters for the crystallization of MIO were as follows:a reaction temperature of 443—453 K,a NaOH concentration 12—14 mol•L^-1 and a reaction time of 250min.

The anionic polymerization of octamethylcyclotetrasiloxane (D4) catalyzed by tetramethyl ammonium hydroxide (TMAH) in the presence of water under the conditions of high temperature and oxygen-off was investigated. The conversion of polymerization and the molecular mass of the polymer were examined by Gel Permeation Chromatography (GPC). Based on mechanism analysis, the calculation model of terminated hydroxy concentration (c_OH) was obtained. And the result of the increase of c_OH with conversion was observed by using the model. Then the influence of reaction conditions on the change of the value of cOH with conversion was investigated.The increase of the hydroxy terminated rate was greater than that of the polymerization rate with increasing temperature.The increase of the polymerization rate was greater than that of the hydroxy terminated rate with the concentration of catalyst increasing. With the concentration of water increasing, the polymerization rate decreased and the hydroxy terminated rate increased.