1. Sin-China Nano Technology Center, Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 10029, China;
2. Nanomaterials Technology Pte. Ltd., Singapore

Homogeneous oxidation using an oil-soluble oxidant,tert-amyl hydroperoxide(TAHP),for ultra-deep desulfurization was performed under mild conditions in the presence of molybdenum oxide catalysts.Dibenzothio-phene(DBT),benzothiophene(BT) and 4,6-dimethyl-dibenzothiophene(DMDBT),which are the refractory sulfur compounds for hydrodesulfurization(HDS),were employed as model substrates for a simulated diesel fuel.Activity of molybdenum oxide supported on a macroporous weak acidic resin was investigated.The mass conversion of DBT reached near 100% at 90℃ and a TAHP/DBT molar ratio of 3 with 1% of molybdenum oxide supported on Amberlite IRC-748 resin for 1 h.It was further found that the activities of the model substrates decreased in the order of DMDBT>DBT>BT.In the flow oxidation using TAHP as the oxidant,mass conversion of DBT increased remarkably from 61.3% to 98.5% when dropping the weight hourly space velocity(WHSV) from 40 h^-1 to 10 h^-1.A series of experiments dealt with selectivity of this oxidation using TAHP revealed that the model unsaturated compounds,i.e.4,6,8-trimethyl-2-nonylene,and 2-methylnaphthalene did not affect the oxidation of DBT.Car-bazole had nearly no effect on the conversion of DBT using TAHP,but had some influence on the one using tert-butyl hydroperoxide(TBHP).The mass conversion of DBT decreased remarkably from 75.2% to 3.6% when the content of carbazole increased from 0 to 500 μg·g^-1.In the flow oxidation using TAHP as the oxidant,the concentration of DBT in model fuels was reduced from 500 μg·g^-1 to 7.2 μg·g^-1 at WHSV of 10 h^-1,and then reduced to 3.8 μg·g^-1 by adsorption of Al₂O₃.

The realuminated H-mordenite catalysts(HM1-4) treated with different concentrations of NaOH and NaAlO₂ aqueous solutions were prepared,and characterized by inductively coupled plasma(ICP),X-ray diffraction(XRD),Fourier transform-infrared spectroscopy(FT-IR) and temperature-programmed desorption of ammonia,They are of lower Si/Al ratio and higher acid amount while keeping a high relative crystallinity.Their catalytic per-formances were evaluated with the liquid-phase tert-butylation of toluene with tert-butyl alcohol in a 100 ml stainless steel batch reactor equipped with a stirrer.HM₂ zeolite catalyst,obtained by treating HM in 0.1 mol·L^-1 NaOH followed by 0.05 mol·L^-1 NaAlO₂ aqueous solution,shows a higher catalytic activity because of its highest acid amount.For HM₂ catalyst the influences of reaction conditions on catalytic performance were investigated.The conversion of toluene is 50.3% and the selectivity of p-tert-butyltoluene is 74.7% at a temperature of 180℃,2 of molar ratio of tert-butyl alcohol to toluene,4h of reaction time and 0.2 of M(catalyst)/M(toluene).

A series of tungsten-substituted molybdophosphoric acids(H₃PMo_12-nWnO₄₀·xH₂O) were synthesized and characterized by inductive coupled plasma atomic emission spectroscopy(ICPAES),thermal gravimetry and differential scanning calorimetry(TG-DSC),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and FTIR pyridine adsorption.The as-prepared heteropoly acids have a Keggin type structure.The synthesis of tetrahydrofuran by reactive distillation and cyclodehydration of 1,4-butanediol was studied using the tungsten-substituted molybdophosphoric acids as catalysts.The results of catalytic test indicated that the catalytic activity increased with the increase in the substitution number(n) of tungsten atom in H₃PMo_12-nWnO₄₀·xH₂O and was constant as the substitution number(n) was more than 8.The catalytic activity increased with the increase in the catalyst loading and the selectivity of tetrahydrofuran was nearly 100%.

A sulfonated poly(ether ether ketone)(SPEEK) membrane with a fairly high degree of sulfonation(DS) can swell excessively and even dissolve at high temperature.To solve these problems,insolvable functionalized silica powder with sulfonic acid groups(SiO_x-S) was added into the SPEEK matrix(DS=55.1%) to prepare SPEEK/SiO_x-S composite membranes.The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiO_x-S powder.Pure SPEEK membrane swelled 52.6% at 80℃,whereas the SPEEK/SiO_x-S(15%,by mass) membrane swelled only 27.3% at the same temperature.From room temperature to 80℃,all SPEEK/SPEEK/SiO_x-S composite membranes had methanol permeability of about o ne order of magnitude lower than that of Nafion 115.Compared with pure SPEEK membranes,the addition of the SiO_x-S powder not only leads to higher proton conductivity,but also increases the dimensional stability at higher temperatures,and greater proton conductivity can be achieved at higher temperature.The SPEEK/SiO_x-S(20%,by mass) membrane could withstand temperature up to 145℃,at which in 100% relative humidity(RH) its proton conductivity exceeded slightly that of Nafion 115 membrane and reached 0.17 S·cm^-1,while pure SPEEK membrane dissolved at 90℃.The SPEEK/SiO_x-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability,high proton conductivity,and low methanol permeability.

The process based on supercritical fluid extraction for reprocessing of the spent nuclear fuel has some remarkable advantages over the plutonium-uranium extraction(PUREX) process.Especially,it can minimize the generation of secondary waste.Dynamic reactive extraction of neodymium oxide(Nd₂O₃) in supercritical carbon dioxide(SC-CO₂) containing tri-n-butyl phosphate-nitric acid(TBP-HNO₃) complex was investigated.Temperature showed a positive effect on the extraction efficiency,while pressure showed a negative effect when the unsaturated TBP-HNO₃ complex was employed for the dynamic reactive extraction of Nd₂O₃ in SC-CO₂.Both temperature and pressure effects indicated that the kinetic process of the reactive extraction was controlled by the chemical reaction.A kinetic model was proposed to describe the extraction process.

The penetration and deposit of particles within the medium is thought to be one reason that the residual pressure drop of the rigid ceramic filter increase with cycle number.In this study,the change in the microstructure of a single layer ceramic filter candle during filtration-cleaning cycle was observed by scanning electron microscope(SEM) and the resistance property of the filter was monitored accordingly.The experimental results show that there exists a serious dust deposit within the filter medium,especially at the surface region.This should be responsible for the decrease of the filter permeability.The deposit law of dust in the filter medium during filtration-cleaning cycle was then studied by measuring the deposit depth,the deposit amount,the particles distribution within the medium,the size distribution of deposited particles,and so on.Particles migration and fine particles penetration were found to be the main reasons,for which dust deposit within the filter medium became aggravated with cycle number.Based on a differential form of Ergun equation,an expression for the pressure drop of a used ceramic filter was developed with a good agreement with experimental results.Then,the effect of dust deposit on the residual pressure drop was studied at the different face velocities and dust sizes.It was found that face velocity and dust size significantly influence dust deposit within filter medium,and then the operation performance of the filter.

Mixed integer linear programming(MILP) approach for simultaneous gross error detection and data reconciliation has been proved as an efficient way to adjust process data with material,energy,and other balance constrains.But the efficiency will decrease significantly when this method is applied in a large-scale problem because there are too many binary variables involved.In this article,an improved method is proposed in order to generate gross error candidates with reliability factors before data rectification.Candidates are used in the MILP objective function to improve the efficiency and accuracy by reducing the number of binary variables and giving accurate weights for suspected gross errors candidates.Performance of this improved method is compared and discussed by applying the algorithm in a widely used industrial example.

A new version of differential evolution(DE) algorithm,in which immune concepts and methods are applied to determine the parameter setting,named immune self-adaptive differential evolution(ISDE),is proposed to improve the performance of the DE algorithm.During the actual operation,ISDE seeks the optimal parameters arising from the evolutionary process,which enable ISDE to alter the algorithm for different optimization problems and improve the performance of ISDE by the control parameters' self-adaptation.The performance of the proposed method is studied with the use of nine benchmark problems and compared with original DE algorithm and other well-known self-adaptive DE algorithms.The experiments conducted show that the ISDE clearly outperforms the other DE algorithms in all benchmark functions.Furthermore,ISDE is applied to develop the kinetic model for homogeneous mercury(Hg) oxidation in flue gas,and satisfactory results are obtained.

In this article,an approach for economic performance assessment of model predictive control(MPC) system is presented.The method builds on steady-state economic optimization techniques and uses the linear quadratic Gaussian(LQG) benchmark other than conventional minimum variance control(MVC) to estimate the potential of reduction in variance.The LQG control is a more practical performance benchmark compared to MVC for performance assessment since it considers input variance and output variance,and it thus provides a desired basis for determining the theoretical maximum economic benefit potential arising from variability reduction.Combining the LQG benchmark directly with benefit potential of MPC control system,both the economic benefit and the optimal operation condition can be obtained by solving the economic optimization problem.The proposed algorithm is illustrated by simulated example as well as application to economic performance assessment of an industrial model predictive control system.

Emodin is a kind of anthraquiones with pharmaceutical activities.The solubilities of emodin in ethanol,1-octanol,and ethanol+1-octanol at different temperatures were measured using an analytical method.The solubility of emodin in these solvents increased with an increase in temperature.With the temperature deviating from room temperature,the dependence of the solubility of emodin on temperature became a lot more remarkable.The solubility of emodin in ethanol was more sensitive to temperature than that in 1-octanol.The solubility data of emodin in the same species of solvent at different temperatures was correlated with an empirical equation.The calculated results agreed with the experimental data well.

A new position group contribution model is proposed for the estimation of normal boiling data of organic compounds involving a carbon chain from C₂ to C₁₈.The characteristic of this method is the use of position distribution function.It could distinguish most of isomers that include cis-or trans-structure from organic compounds.Contributions for hydrocarbons and hydrocarbon derivatives containing oxygen,nitrogen,chlorine,bromine and sulfur,are given.Compared with the predictions,results made use of the most common existing group contribution methods,the overall average absolute difference of boiling point predictions of 417 organic compounds is 4.2 K;and the average absolute percent derivation is 1.0%,which is compared with 12.3 K and 3.2% with the method of Joback,12.1 K and 3.1% with the method of Constantinou-Gani.This new position contribution groups method is not only much more accurate but also has the advantages of simplicity and stability.

In this study,three semipredictive activity coefficient models:Wilson,non-random-two liquid model(NRTL),and universal quasi-chemical model(UNIQUAC),have been used for modeling vapor-liquid equilibrium properties of ternary mixtures that include substances found in alcoholic distillation processes of wine and musts.In particular,vapor-liquid equilibrium in ternary mixtures containing water+ethanol+congener has been modeled using parameters obtained from binary and ternary mixture data.The congeners are substances that although present in very low concentrations,of the order of part per million,are important enological parameters.The results given by these different models have been compared with literature data and conclusions about the accuracy of the models studied are drawn,recommending the best models for correlating and predicting phase equilibrium properties of this type of mixtures.

A fully flexible potential model for carbon dioxide has been developed to predict the vapor-liquid coexistence properties using the NVT-Gibbs ensemble Monte Carlo technique(GEMC).The average absolute deviation between our simulation and the literature experimental data for saturated liquid and vapor densities is 0.3% and 2.0%,respectively.Compared with the experimental data,our calculated results of critical properties(7.39 MPa,304.04 K,and 0.4679 g·cm^-3) are acceptable and are better than those from the rescaling the potential parameters of elementary physical model(EPM2).The agreement of our simulated densities of supercritical carbon dioxide with the experimental data is acceptable in a wide range of pressure and temperature.The radial distribution function estimated at the supercritical conditions suggests that the carbon dioxide is a nonlinear molecule with the C=O bond length of 0.117 nm and the O=C=O bond angle of 176.4°,which are consistent with Car-Parrinello molecular-dynamics(CPMD),whereas the EPM2 model shows large deviation at supercritical state.The predicted self-diffusion coefficients are in agreement with the experiments.

The main aim of this research was the experimental study at lab scale to check the absorption technology for the in situ removal of H₂S from biogas during anaerobic digestion process.The reagent FeCl₃ was used to check the removal efficiency of H₂S produced from dairy manure during anaerobic bioconversion process.The experiments were conducted under mesophilic conditions.The composition of biogas was analyzed by gas chromatography analyzer equipped with flame photometer and thermal conductivity detectors.Experimental results under the same conditions demonstrate that high concentration of H₂S in the form of FeS can be removed totally from the biogas using FeCl₃ dosing with in anaerobic batch digester.

A strain isolated from the fruiting body of a fungus parasitized on Elaphomyces was identified as Cordyceps ophioglossoides based on the morphological characteristics and the analysis of ITS-5.8s rDNA sequence.The optimal medium composition(g·L^-1),containing sucrose 66.0,yeast powder 10.0,silkworm chrysalises digest 30.0,MgSO₄·7H₂O 0.4,and KH₂PO₄ 0.4,was found using fractional factorial design and a central composite design,and the optimization of cultural conditions obtained a result of seed age 6 days,inoculum size 6%(by volume),initial pH 5.6,temperature 24℃,shaking speed 160 r·min^-1 by one-factor-at-a-time method.The maximum biomass reached about 20.2 g·L^-1 after 90 hours culture under the optimal conditions.Elementary pharmacological activities showed that mycelia of C.ophioglossoides L2 from submerged culture promoted uterus growth in estrogendepleted mice.In the 15-litre scale-up fermentation,the mycelial biomass was around 19.1 g·L^-1,indicating a promising prospect for this biotechnology and the potency to develop its medical value.

Based on use of multi-dimensional models,this investigation simulates the performance of a proton exchange membrane fuel cell by varying the channel pattern.In the one-dimensional model,the porosity of the gas diffusion layer is 0.3.The model reveals the water vapor distribution of the fuel cell and demonstrates that the amount of water vapor increases linearly with the reduction reaction adjacent to the gas channel and the gas diffusion layer.Secondly,four novel tapered gas channels are simulated by a two-dimensional model.The model considers the distributions of oxygen,the pressure drop,the amount of water vapor distribution and the polarization curves.The results indicate that as the channel depth decreases,the oxygen in the tapered gas channel can be accel-erated and forced into the gas diffusion layer to improve the cell performance.The three-dimensional model is employed to simulate the phenomenon associated with four novel tapered gas channels.The results also show that the best performance is realized in the least tapered gas channel.Finally,an experimentally determined mechanism is found to be consistent with the results of the simulation.

This study describes a novel micro proton exchange membrane fuel cell(PEMFC)(active area,2.5 cm²).The flow field plate is manufactured by applying micro-electromechanical systems(MEMS) technology to silicon substrates to etch flow channels without a gold-coating.Therefore,this investigation used MEMS technology for fabrication of a flow field plate and presents a novel fabrication procedure.Various operating parameters,such as fuel temperature and fuel stoichiometric flow rate,are tested to optimize micro PEMFC performance.A single micro PEMFC using MEMS technology reveals the ideal performance of the proposed fuel cell.The optimal power density approaches 232.75 mW·cm^-1 when the fuel cell is operated at ambient condition with humidified,heated fuel.

This article aims to investigate the transient behavior of a planar direct internal reforming solid oxide fuel cell(DIR-SOFC) comprehensively.A one-dimensional dynamic model of a planar DIR-SOFC is first developed based on mass and energy balances,and electrochemical principles.Further,a solution strategy is presented to solve the model,and the International Energy Agency(IEA) benchmark test is used to validate the model.Then,through model-based simulations,the steady-state performance of a co-flow planar DIR-SOFC under specified initial operating conditions and its dynamic response to introduced operating parameter disturbances are studied.The dynamic responses of important SOFC variables,such as cell temperature,current density,and cell voltage are all investigated when the SOFC is subjected to the step-changes in various operating parameters including both the load current and the inlet fuel and air flow rates.The results indicate that the rapid dynamics of the current density and the cell voltage are mainly influenced by the gas composition,particularly the H₂ molar fraction in anode gas channels,while their slow dynamics are both dominated by the SOLID(including the PEN and interconnects) temperature.As the load current increases,the SOLID temperature and the maximum SOLID temperature gradient both increase,and thereby,the cell breakdown is apt to occur because of excessive thermal stresses.Changing the inlet fuel flow rate might lead to the change in the anode gas composition and the consequent change in the current density distribution and cell voltage.The inlet air flow rate has a great impact on the cell temperature distribution along the cell,and thus,is a suitable manipulated variable to control the cell temperature.

The nanoparticles of the hydrophobic drug of danazol with narrow size distribution are facilely prepared by controlled high-gravity anti-solvent precipitation(HGAP) process.Intensified micromixing and uniform nucleation environment are created by the high-gravity equipment(rotating packed bed) in carrying out the anti-solvent precipitation process to produce nanoparticles.The average particle size decreases from 55 μm of the raw danazol to 190 nm of the nanoparticles.The Brunauer-Emmett-Teller(BET) surface area sharply increases from 0.66 m²·g^-1 to 15.08 m²·g^-1.Accordingly,the dissolution rate is greatly improved.The molecular state,chemical composition,and crystal form of the danazol nanoparticles remains unchanged after processing according to Fourier transform infrared(FTIR) and X-ray diffraction(XRD).The high recovery ratio and continuous production capacity are highly appreciated in industry.Therefore,the HGAP method might offer a general and facile platform for mass production of hydrophobic pharmaceutical danazol particles in nanometer range.

Polyethersulfone(PES) is widely used as biomaterials due to its thermal stability,mechanical strength,and chemical inertness.Nevertheless,their blood compatibility is still not adequate for hemodialysis and blood purification.In this study,the sulfonated polyethersulfone(SPES) was synthesized through an electrophilic substitution reaction,and PES/SPES blending membranes were prepared.The characterization of the SPES was studied by FTIR.The water adsorption and water contact angle experiments show that the hydrophilicity of PES/SPES blend membrane was improved as for the sulfonate group existing in the SPES.Moreover,PES/SPES blend membrane could effectively reduce bovine serum albumin adsorption and prolong the blood coagulation time compared with the PES membrane,thereby improving blood compatibility.

A laboratory-scale reaction-crystallization process of struvite synthesis from diluted water solution of Mg²⁺,NH₄⁺ and PO₄^3- ions was studied.The research covered the tests of two original constructions of continuous jet-pump Draft Tube Magma(DTM)-type crystallizers with internal circulation of suspension(upward/downward).Interactions between constructional,hydrodynamic and kinetic factors were established and discussed.Nucleation and linear growth rates of struvite crystals were calculated on the basis of population density distribution.Kinetic model of idealized Mixed Suspension Mixed Product Removal(MSMPR) crystallizer considering the size-dependent growth mechanism was applied(Rojkowski hyperbolic equation).For comparison purposes the kinetic data corresponded to a simpler,continuous draft tube-type crystallizer equipped with propeller agitator were analyzed.It was concluded that crystal product of larger size was withdrawn from the jet-pump DTM crystallizer of the descending flow of suspension in a mixing chamber.

An experimental study was carried out to understand the phenomena of the boiling flow of liquid nitrogen in inclined tubes with closed bottom by using the high speed digital camera.The tubes in the experiment are 0.018 m and 0.014 m in inner diameter and 1.0 m in length.The range of the inclination angles is 0-45° from the vertical.The statistical method is employed to analyze the experimental data.The experiment was focused on the effect of the inclination angle on the initial position distribution of Taylor bubbles.The formation criterion of Taylor bubbles was confirmed by analyzing the images of Taylor bubbles.The experimental results show that the initial position of Taylor bubble increased first,and then decreased with the increasing inclination angle,with the maximum at 30°.The standard deviation of the initial position of Taylor bubble in tubes was different with different inner diameters.The lognormal shape was fitted to the measured the initial position distributions of Taylor bubbles in the cryogenic tubes.

Based on the solubility in supercritical CO₂,two strategies in which CO₂ plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies.The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 μm can be made via solution enhanced dispersion by supercritical fluids(SEDS) process,in which CO₂ worked as turbulent anti-solvent;while for astaxanthin,micronized particles with mean particle size of 0.3-0.8 μm were also made successfully by rapid expansion supercritical solution(RESS) process.

Pretreatment of the corn stover powder by dilute sulphuric acid(solid-liquid ratio 1:20) at 130℃ for 30 min was carried out with 89.09% of the hemicellulose removed.After filtration,the xylose-rich corn stover pretreatment liquid,whose fermentable sugar was from hemicellulose hydrolysis only,consisting of 81.16% xylose and 15.27% glucose,was used to cultivate genetic recombinant Escherichia coli BL21 with human-like collagen(HLC) expression enhanced by 50.00% and 63.71% xylose consumption.

Macro and micromixing time represent two extreme mixing time scales,which governs the whole hydrodynamics characteristics of the surface aeration systems.With the help of experimental and numerical analysis,simulation equation governing those times scale has been presented in the present work.